[Federal Register Volume 65, Number 78 (Friday, April 21, 2000)]
[Proposed Rules]
[Pages 21548-21574]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-9655]
[[Page 21547]]
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Part III
Environmental Protection Agency
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40 CFR Part 435
Effluent Limitations Guidelines for the Oil and Gas Extraction Point
Source Category; Proposed Rule
Federal Register / Vol. 65, No. 78 / Friday, April 21, 2000 /
Proposed Rules
[[Page 21548]]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 435
[FRL-6581-4]
Effluent Limitations Guidelines for the Oil and Gas Extraction
Point Source Category
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed Rule; Supplemental information and notice of meeting.
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SUMMARY: On February 3, 1999 (64 FR 5488), EPA proposed technology-
based effluent limitations guidelines and standards under the Clean
Water Act (CWA) for the discharge of pollutants from oil and gas
drilling operations associated with the use of synthetic-based drilling
fluids (SBFs) and other non-aqueous drilling fluids into waters of the
United States. This proposed rule would apply to certain existing and
new facilities in the offshore subcategory beyond three miles from
shore and offshore of Alaska, and the Cook Inlet, Alaska, portion of
the coastal subcategory of the oil and gas extraction point source
category.
This document presents a summary of all data received and collected
by EPA since publication of the proposal; an assessment of the
usefulness of the data in EPA's analyses; summary descriptions of
revised engineering and economic models; and updated modeling results
incorporating the new data. This notice also discusses ``best
management practices'' (BMPs) as potential alternative requirements to
reduce the discharges of toxic and hazardous pollutants.
DATES: Submit your comments by June 20, 2000. A public meeting will be
held on Tuesday, April 25, 2000, from 1:00 p.m. to 5:30 p.m. Central
Standard Time.
ADDRESSES: Submit comments by mail to Mr. Carey A. Johnston at the
following address: U.S. Environmental Protection Agency; Engineering
and Analysis Division (4303); 1200 Pennsylvania Avenue, NW; Washington,
DC 20460. Please submit any references cited in your comments. EPA
would appreciate an original and two copies of your comments and
enclosures (including references). Hand delivered comments may be
submitted at the EPA Headquarters Water Docket (address below).
Comments may also be filed electronically to
``[email protected].'' Electronic comments sent to the above e-
mail address will be treated like all other submitted comments.
The data and analyses being announced today are available for
review in the EPA Water Docket at EPA Headquarters at Waterside Mall,
Room EB-57, 401 M. St. SW, Washington, DC 20460. For access to the
docket materials, call (202) 260-3027 between 9:00 a.m. and 4:00 p.m.
for an appointment. A reasonable fee may be charged for copying.
The public meeting will be held at the Minerals Management Service
(MMS), Gulf of Mexico OCS Region Office, Room 111, 1201 Elmwood Park
Boulevard, New Orleans, LA, 70123-2394.
FOR FURTHER INFORMATION CONTACT: For additional technical information,
contact Mr. Carey A. Johnston at (202) 260-7186 or at the following e-
mail address: [email protected]. For additional economic
information contact Mr. James Covington at (202) 260-5132 or at the
following e-mail address: [email protected].
SUPPLEMENTARY INFORMATION: Visitors attending the New Orleans public
meeting (see Addresses) will need to sign in at the MMS guard booth and
obtain a visitors badge. If you wish to present formal comments at the
public meeting you should have a written copy for submittal. No meeting
materials will be distributed in advance of the public meeting; all
materials will be distributed at the meeting. Limited teleconferencing
capability will be available for the meeting. Persons wishing to
participate via telephone or who have special audio-visual needs should
contact Mr. Carey A. Johnston, (202) 260-7186.
The Agency invites all parties to coordinate their data collection
activities with EPA to facilitate mutually beneficial and cost-
effective data submissions. Please refer to the For Further Information
Contact for technical contacts at EPA.
To ensure that EPA can properly respond to comments, the Agency
prefers that commenters cite, where possible, the paragraph(s) or
sections in the notice or supporting documents to which each comment
refers. Please submit an original and two copies of your comments and
enclosures (including references).
Commenters who want EPA to acknowledge receipt of their comments
should enclose a self-addressed, stamped envelope. No facsimiles
(faxes) will be accepted. Comments and data will also be accepted on
disks in Wordperfect, ASCII, or Adobe Acrobat (*.pdf) format.
All comments will be organized by EPA's Engineering and Analysis
Division (EAD) and submitted by EAD to the record supporting this
rulemaking (Docket No. W-98-26) in the EPA Water Docket. Electronic
comments must be submitted as a Wordperfect, ASCII, or Adobe Acrobat
(*.pdf) format file avoiding the use of any form of encryption.
Electronic comments must be identified by the docket number W-98-26 and
may be filed online at many Federal Depository Libraries. No
confidential business information (CBI) should be sent via e-mail.
EPA's information technology services (e.g., e-mail, website) were
temporarily shut down, beginning Thursday, February 17, in order to
review and improve security measures. EPA's e-mail services are now
operational. However, EPA recommends that persons submitting comments
electronically call Mr. Carey A. Johnston, (202) 260-7186, to confirm
EPA receipt.
Contents of This Document
I. Purpose of this Notice
II. Overview of Proposal and Data Acquired Since the Proposal
III. Revised Models
IV. Revised Analyses
V. Best Management Practices (BMPs) Alternatives to Numeric
Limitations and Standards
I. Purpose of This Notice
On February 3, 1999 (64 FR 5488), EPA proposed technology-based
effluent limitations guidelines and standards under the Clean Water Act
(CWA) for the discharge of pollutants from oil and gas drilling
operations associated with the use of synthetic-based drilling fluids
(SBFs) and other non-aqueous drilling fluids into waters of the United
States. This proposed rule would apply to certain existing and new
facilities in the offshore subcategory (i.e., facilities seaward of the
inner territorial boundary) and the Cook Inlet, Alaska, portion of the
coastal subcategory of the oil and gas extraction point source
category.
In this notice, EPA is making new data submissions available for
comment. Additionally, EPA is providing descriptions of revised
economic and engineering models incorporating the new data. Summary
descriptions of updated modeling results are also given in this notice.
This notice also discusses ``best management practices'' (BMPs) as
potential alternative requirements to reduce the discharges of toxic
and hazardous pollutants. Finally, this notice announces that EPA has
submitted an Information Collection Request (ICR) to the Office of
Management and Budget (OMB) for these BMP alternatives to numeric
effluent limitations and standards. EPA solicits public comment on any
of the
[[Page 21549]]
issues or information presented in this notice of data availability and
in the administrative record supporting this notice.
II. Overview of Proposal and Data Acquired Since the Proposal
Since about 1990, the oil and gas extraction industry developed
SBFs with synthetic and non-synthetic oleaginous (oil-like) materials
as the base fluid to provide the drilling performance characteristics
of traditional oil-based fluids (OBFs) based on diesel and mineral oil,
but with lower environmental impact and greater worker safety through
lower toxicity, elimination of polynuclear aromatic hydrocarbons
(PAHs), faster biodegradability, lower bioaccumulation potential, and,
in some drilling situations, less drilling waste volume.
EPA's information to date, including limited seabed surveys in the
Gulf of Mexico, indicate that the effect zone of the discharge of
certain SBFs is within a few hundred meters of the discharge point.
These surveys also indicate that the sea floor may significantly
recover in one to two years. EPA believes that impacts are primarily
due to smothering by the drill cuttings, changes in sediment grain size
and composition (physical alteration of habitat), and anoxia (absence
of oxygen) caused by the decomposition of the base fluid. The benthic
smothering and changes in grain size and composition from the cuttings
are effects that are also associated with the discharge of water-based
drilling fluids (WBFs) and associated cuttings. Based on the record to
date, EPA finds that these impacts, which are believed to be of limited
duration, are less harmful to the environment than the non-water
quality environmental impacts associated with the option of prohibiting
the discharge of all SBF-wastes. Moreover, EPA prefers SBFs over OBFs
as there are operational accidents that lead to spills and loss of
drilling fluid to the environment.
The proposed rule, published on February 3, 1999 (64 FR 5488),
identified possible methods to control SBF discharges associated with
cuttings (SBF-cuttings) in a way that reflects the appropriate level of
technology. EPA proposed using stock limitations and standards on the
base fluids from which the drilling fluids are formulated. This would
ensure that substitution of synthetic and other oleaginous base fluids
for traditional mineral oil and diesel oil reflects the appropriate
level of technology. In other words, EPA wants to ensure that only the
SBFs formulated from the ``best'' base fluids are allowed for
discharge. Parameters that distinguish the various base fluids are the
PAH content, sediment toxicity, rate of biodegradation, and potential
for bioaccumulation.
EPA also proposed that SBF-cuttings should be controlled with
discharge limitations and standards, such as a limitation on the
toxicity of the SBF at the point of discharge, and a limitation on the
mass (as volume) or concentration of SBFs discharged. The latter type
of limitation would take advantage of the solids separation
efficiencies achievable with SBFs, and consequently minimize the
discharge of organic and toxic components. Additionally, EPA proposed
that SBF discharges not associated with cuttings (e.g., incidental
spills, accumulated solids, deck drainage) should meet zero discharge
requirements, as this is the current industry practice due to the value
of these drilling fluids.
Since proposal, EPA has obtained additional data and information
from the industry and the Agency's continued data collection
activities. The Agency has included these data, information, and the
preliminary results of EPA's evaluation in sections III.A through III.H
of the supporting record of this notice, available for review in the
Water Docket (see Addresses section at the beginning of this notice).
The industry data submittals are related to stock limitations and
standards on base fluid (e.g., PAH content, sediment toxicity,
biodegradation, bioaccumulation), discharge limitations and standards
(e.g., free oil, formation oil contamination, retention of SBF on
cuttings), technical performance of ester-based drilling fluids, subsea
pumping systems, cuttings microencapsulation systems, best management
practices (BMPs), and health and safety considerations. The specific
data, information, and comments provided to EPA are discussed below in
detail.
The Agency's collected data are related to stock limitations and
standards (e.g., sediment toxicity and biodegradation); non-water
quality environmental impacts (NWQI) including on-shore disposal
capacity of exploration and production wastes and monetization of air
emissions; economic costs related to deepwater projects; discharge
limitations and standards; and projected environmental outcomes such as
sediment pore water quality.
EPA will evaluate all analytical data in the rulemaking record to
set limitations and standards that represent the appropriate level of
technology using a combination of methods referenced below.
Specifically, for sediment toxicity and biodegradation limitations and
standards, EPA will evaluate each of the various sediment toxicity and
biodegradation method test data for the various synthetic base fluids
against known standards such as diesel. Moreover, EPA will use all
sediment toxicity and biodegradation data to assess the ability of each
sediment toxicity and biodegradation method identified below to
discriminate between different types of synthetic base fluids and
produce consistent results.
In addition, a list of SBF rulemaking stakeholder meetings and the
respective minutes can be found in section III.A.(c) of the rulemaking
record.
A. Industry Data Submissions Since Proposal Publication
1. Sediment Toxicity Test Results and Revised Methods
In the February 1999 proposal, EPA set the Best Available
Technology Economically Achievable (BAT) and New Source Performance
Standards (NSPS) stock limitation for sediment toxicity as: ``10-day
LC50 of stock base fluid minus 10-day LC50 of
C16-C18 internal olefin shall not be less than
zero.'' [The term ``LC50'' is used to identify how much of a
substance is needed to kill half of a group of experimental organisms
in a given time; a higher LC50 value means the material is
less toxic]. EPA also proposed a compliance method, American Society
for Testing and Material (ASTM) method E1367-92, and sediment
preparation procedures for this stock limitation (Appendix 3 to Subpart
A of Part 435).
In addition to sediment toxicity tests using ASTM method E1367-92,
industry has recently conducted several studies using alternative
sediment toxicity test methods including a method based on determining
toxicity to the mysid shrimp, Mysidopsis bahia, in a sediment-water
interface system. As a result of this effort, industry has supplied
information on the use of formulated sediments and the shortening of
the exposure period of synthetic base fluids to marine amphipods. EPA
proposes to use one of these methods (i.e., ASTM method E1367-92 or
alternative industry mysid shrimp sediment toxicity test method) for:
(1) the establishment of an appropriate sediment toxicity rate stock
limitation in the final rule; and (2) use as a compliance tool.
Several papers published by M-I Drilling Fuids, L.L.C. (MIDF)
provided data on the toxicity of the synthetic base fluid
C16-C18 internal olefin (IO) and
[[Page 21550]]
diesel in formulated sediments as well as data on the results of tests
conducted with a 96-hour exposure period as compared to the standard
10-day exposure as specified in ASTM E1367-92 (Rabke and Candler, 1998;
Rabke and Candler, 1999; Still, et al., 1999).
This work conducted by MIDF was done in an effort to increase the
discriminatory power of the test between the toxicity of synthetic base
fluids and diesel, as well as between the different synthetic base
fluids. MIDF believes that the longer exposure time reduces
discriminatory power because the test sediment toxicity becomes a
greater factor relative to the test base fluid toxicity over time.
Therefore, the test sediment's toxicity would tend to normalize and
obscure the differences in toxicities of the test base fluids as test
duration increases. Table II.A.1.1 summarizes the LC50
industry sediment toxicity data with various drilling fluids [i.e.,
diesel, internal olefin (IO), linear alpha olefin (LAO), poly alpha
olefin (PAO), and ester]. A more complete review of these procedures
and data can be found in section III.B.(b) of the rulemaking record.
Table II.A.1.1: Industry LC50 Sediment Toxicity Data for Various Drilling Base Fluids at Two Different Time
Periods
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95% Confidence
Drilling base fluid LC50 (mg/Kg) interval
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Baker Hughes INTEQ-Generated Data
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96-Hour Test................................. C14/16/18 IO................... 4020 2926-8219
C14/16/18/20 IO................ >5111 NA
C16/18 IO...................... 3515 2726-5215
C14/15/16/17/18 LAO/IO......... 1497 1299-1725
10-Day Test.................................. Diesel......................... 343 297-391
C14/16/18 IO................... 646 625-1250
C14/16/18/20 IO................ 1218 1070-1453
C16/18 IO...................... 1464 1172-1681
C14 LAO........................ 205 187-223
C16 LAO........................ 407 353-473
C14/15/16/17/18 LAO/IO......... 854 696-1018
C30+PAO........................ 2359 1478-5156
Enhanced Mineral Oil........... 79 37-117
Linear Paraffin................ 1047 846-1257
Paraffin....................... 111 101-122
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Baroid-Generated Data
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96-Hour Test................................. Diesel......................... 453 416-493
IO............................. 876 442-1663
LAO............................ 490 291-924
Ester.......................... >20000 NA
Ester (Low viscosity).......... >20000 NA
10-Day Test.................................. Diesel......................... 230 209-251
IO............................. 564 447-639
LAO............................ 338 294-378
Ester.......................... >10000 NA
Ester (Low viscosity).......... 2447 2197-2701
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MIDF Drilling-Generated Data
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96-Hour Test................................. Diesel......................... 566 510-629
IO............................. 3686 2890-4893
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Method Reference: EPA February 1999 Proposal (64 FR 5488).
Finally, one commenter on the February 1999 proposal, Baroid
Drilling Fluids, provided preliminary sediment toxicity data for two of
its ester-based drilling fluids. The data provided in the comments
indicate that both esters may have lower toxicities than other base
fluids (e.g., C16-C18 IO, paraffin, mineral oil,
diesel oil). However, EPA data presented in Table II.B.1.1 indicate
that the sediment toxicity of IO and ester are significantly better
than other alternative base fluids.
2. Biodegradation Test Results and Revised Methods
In the February 1999 proposal, EPA set the BAT and NSPS stock
limitation for biodegradation rate as: ``percent stock base fluid
degraded at 120 days minus percent C16-C18
internal olefin degraded at 120 days shall not be less than zero.'' EPA
also proposed a compliance method for this stock limitation (Appendix 4
to Subpart A of Part 435).
Industry stakeholders conducted a series of biodegradation tests
for determining biodegradation of SBFs and OBFs using the method
proposed by EPA (Appendix 4). Industry stakeholders also identified
alternative analytical biodegradation methods and used these
alternative methods to generate data. EPA solicits comment in this
notice on use of these alternative methods and corresponding data to
set biodegradation limitations and standards and compliance methods.
EPA proposes to use one of these methods for: (1) The establishment of
an appropriate biodegradation rate stock limitation in the final rule;
and (2) use as a compliance tool. The first analytical test method is
the solid-phase degradation test as EPA proposed in February 1999
(Appendix 4). This method consists of spiking ``clean'' marine or
estuarine sediment with a base fluid and placing these test samples in
exposure tanks filled with seawater. The concentration of base fluid is
measured at regular intervals during the test to monitor the
degradation of the base fluid.
[[Page 21551]]
Industry-supplied data using the solid phase test are summarized in
Table II.A.2.1.
Table II.A.2.1: Industry Solid Phase Biodegradation Test Results
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Percent loss relative to day 0
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Elapsed time of test Finagreen C16-C18 Neodene
Olive oil ester Diesel Internal 1518
(percent) (percent) (percent) olefin (percent)
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Day 10............................... 84 56 * * *
Day 20............................... 88 59 * * *
Day 45............................... 96 90 -2 39 2
Day 110.............................. 99 95 22 73 58
Day 186.............................. 99 99 55 93 83
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Method Reference: EPA February 1999 Proposal (64 FR 5488).
*Not tested.
The second biodegradation method evaluated by industry is the
marine anaerobic closed bottle test. This test procedure places a
mixture of SBFs or OBFs, marine sediment, and sea water into a tightly
capped clean serum bottle. The conditions within the closed bottle
result in the anaerobic degradation of SBFs or OBFs. The anaerobic
processes degrading the base fluids produce gas. This gas production is
monitored as a measure of the degradation process. Industry-supplied
data using the closed bottle test are summarized in Table II.A.2.2.
Table II.A.2.2: Industry Marine Anaerobic Closed Bottle Biodegradation Test Results
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Cumulative gas production over time (ml)
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C14-C16
Elapsed time of test C16-C18 linear Synthetic Blank
Olive oil internal alpha paraffin C30 control
olefin olefin
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Day 0............................. 0.00 0.00 0.00 0.00 0.00 0.00
Day 5............................. 9.29 2.77 3.67 3.32 3.32 3.88
Day 25............................ 50.00 8.59 10.00 7.05 6.62 5.99
Day 33............................ 103.50 12.50 15.00 10.00 8.00 8.30
Day 67............................ 150.41 18.38 22.15 13.67 10.45 11.12
Day 77............................ 152.50 22.21 26.46 15.83 12.42 12.28
Day 95............................ 160.61 24.60 32.74 18.16 12.18 12.98
Day 113........................... 162.88 29.71 42.91 21.14 12.80 13.30
Day 132........................... 164.78 39.74 55.50 23.17 13.38 14.01
Day 155........................... 169.18 59.00 88.16 27.19 15.42 16.07
Day 194........................... 167.74 92.36 114.50 25.82 13.97 14.57
Day 231........................... 171.57 104.50 138.22 29.49 17.47 17.63
Day 271........................... 175.58 119.88 151.20 33.33 21.63 22.11
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Method Reference: ISO 11734: ``Water quality--Evaluation of the `ultimate' anaerobic biodegradability of organic
compounds in digested sludge--Method by measurement of the biogas production'' (1995 edition).
The third biodegradation test method is the respirometry test. This
analytical method determines biodegradation by measuring the carbon
dioxide production and/or oxygen consumption due to microbial oxidation
of the test fluid in sediment. Industry-supplied data using the
respirometry test are summarized in Table II.A.2.3.
Table II.A.2.3: Industry Respirometry Biodegradation Test Results
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Cumulative oxygen consumption over time (mg)
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Elapsed time of test Rapeseed oil Amodrill 1000
Blank control control SBF
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Day 1........................................................... 3.38 4.57 4.46
Day 2........................................................... 6.26 8.26 6.62
Day 3........................................................... 6.52 9.03 10.49
Day 4........................................................... 12.68 22.29 14.13
Day 5........................................................... 16.42 34.29 18.43
Day 6........................................................... 18.50 41.33 21.02
Day 7........................................................... 21.40 50.02 24.67
Day 8........................................................... 24.02 58.42 27.96
Day 9........................................................... 26.66 66.12 31.19
Day 10.......................................................... 29.10 72.88 34.36
Day 11.......................................................... 31.48 78.86 37.25
Day 12.......................................................... 33.88 84.26 39.96
Day 13.......................................................... 36.27 89.00 42.67
Day 14.......................................................... 38.80 93.33 45.48
Day 15.......................................................... 41.28 97.26 48.24
Day 16.......................................................... 43.31 100.76 50.96
Day 17.......................................................... 45.19 103.86 53.47
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Day 19.......................................................... 49.29 110.34 58.86
Day 20.......................................................... 50.80 112.69 60.76
Day 21.......................................................... 52.53 115.34 62.78
Day 22.......................................................... 54.23 117.98 64.83
Day 23.......................................................... 55.73 120.38 66.57
Day 26.......................................................... 60.94 127.73 72.97
Day 27.......................................................... 62.32 129.64 74.76
Day 28.......................................................... 64.00 131.77 76.66
Day 29.......................................................... 65.60 133.81 78.81
Day 30.......................................................... 67.14 135.75 81.04
Day 31.......................................................... 68.59 137.53 82.97
Day 32.......................................................... 70.10 139.32 84.96
Day 33.......................................................... 71.66 141.13 86.98
Day 34.......................................................... 73.09 143.45 88.84
Day 35.......................................................... 74.82 144.51 91.08
Day 36.......................................................... 76.29 146.15 93.17
Day 37.......................................................... 77.47 147.59 94.68
Day 38.......................................................... 79.11 149.22 96.82
Day 39.......................................................... 80.64 150.80 98.87
Day 40.......................................................... 82.31 152.51 101.26
Day 41.......................................................... 83.44 153.83 102.68
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Note: data were not collected on Days 18, 24, and 25.
Method Reference: Modification of OPPTS 835.3110: ``Fate, Transport and Transformation Test Guidelines: Ready
Biodegradability,'' EPA 712-C-98-076, January 1998.
A more complete review of these procedures and data can be found in
section III.B.(b) of the rulemaking record.
Finally, one commenter on the February 1999 proposal, American
Petroleum Institute/National Ocean Industries Association (API/NOIA),
stated, without any supporting data, that esters biodegrade more
quickly than the alternative non-aqueous fluid systems. EPA agrees with
this statement based on recent EPA biodegradation test results (see
section II.B.2).
3. Formation Oil Contamination (Offshore and On-shore Tests)
In the February 1999 proposal, EPA proposed the BAT limitation and
NSPS for formation oil as zero discharge. EPA also proposed a screening
method [Reverse Phase Extraction (RPE) method given in Appendix 6 to
Subpart A of Part 435] and an assurance method [Gas Chromatograph/Mass
Spectrometer (GC/MS) method given in Appendix 5 to Subpart A of Part
435] for determining compliance. These methods continue to be EPA's
preferred option for the final rule.
Industry has sponsored research regarding both of these analytical
methods for determining formation oil contamination. The RPE procedure
is to be used offshore. It measures ultraviolet (UV) fluorescence to
detect the presence of aromatic compounds. Since proposal, refinements
have been made in the test to minimize interference from emulsifiers. A
more complete review of this procedure can be found in section
III.B.(b) of the rulemaking record.
The GC/MS method is expected to be performed in a land-based
laboratory. This procedure, which measures the area under GC peaks and
target aromatics, is a dependable laboratory technique proposed by EPA
to supplement the RPE test for verification purposes. A more complete
review of this procedure can be found in section III.B.(b) of the
rulemaking record.
4. SBF on Cuttings Retention Data
In this section, EPA summarizes the relationship of the industry
supplied data to EPA's proposal, the relationship of these data to
reductions in discharges to the environment, and the SBF on cuttings
data submitted by industry.
a. SBF on Cuttings Data in Relation to EPA's Proposal. In February
1999, EPA proposed a BAT limitation and NSPS for base fluid retained on
cuttings as a maximum value of 10.2 percent, not to be exceeded by the
weighted average for retention over the course of drilling a well. EPA
also proposed a method for demonstrating compliance with this discharge
limitation (Appendix 7 to Subpart A of Part 435). In today's notice
EPA, with input from industry, presents the proposed option along with
several alternatives utilizing Best Management Practices (BMPs). EPA is
considering three options for the final rule for the BAT limitation and
NSPS controlling SBF retained on discharged cuttings: (1) a single
numeric discharge limitation with an accompanying compliance test
method; (2) allowing operators to choose either a single numeric
discharge limitation with an accompanying compliance test method, or as
an alternative, a set of BMPs that employs limited cuttings monitoring;
or (3) allowing operators to choose either a single numeric discharge
limitation with an accompanying compliance test method or an
alternative set of BMPs that employ no cuttings monitoring.
Further EPA corrected technical errors in the proposed rule based
on the statistical analysis of the SBF on cuttings data obtained from
the Gulf of Mexico (GOM). The average percent SBF on cuttings was
corrected from 11.5 to 11.4 for current practice and from 7.11 to 7.09
for the BAT/NSPS technology. The proposed well averaged maximum
limitation and standard were corrected from 10.2 to 9.42. Cost and
loading calculations presented in the February 1999 SBF technical
support documents were not affected by these changes because these
calculations were based on the rounded values of 11 for current
practice and 7 for the BAT/NSPS technology. The technical errors
requiring these changes were related to EPA's calculation of drilling
intervals.
EPA calculates drilling intervals as the depth drilled since the
last measurement for retention on cuttings.
[[Page 21553]]
EPA uses this measurement in conjunction with pipe diameter to estimate
the volume of cuttings associated with a particular retention on
cuttings measurement. EPA then uses this volume in the weighted summary
statistics for the retention on cuttings data. Some data used at
proposal were submitted with drilling intervals already calculated and
other data were submitted with depth measurements calculated from the
ocean floor. In the proposed rule as published in the Federal Register,
EPA used both sets of measurements as if they all represented drilling
intervals. However, in the record for the proposed rule, EPA calculated
and used drilling intervals for those data submitted with depth
measurements calculated from the ocean floor. More information on these
errors and the corrections is given in section I.C(d)(59) of the
rulemaking record.
Several comments received on the February 1999 proposal related to
the use of cuttings retention data from the North Sea to set the GOM
numeric guidelines and standards for percent retention. As discussed
below, EPA has subsequently obtained sufficient data from the GOM to
set limitations and standards without use of the North Sea data.
b. Relationship of SBF on Cuttings Retention Data to Protection of
the Environment. Cuttings retention data measure the amount of residual
drilling fluid retained on cuttings. A higher cuttings retention value
indicates that more drilling fluid is adhering to the cuttings. EPA is
interested in the cuttings retention measurement not only as an
indicator of the amount drilling fluid discharged into the ocean but
also as an indicator of the ability of cuttings to biodegrade and
disperse and not form deleterious cuttings piles and mats. Moreover,
understanding the fate and transport of discharged cuttings is an
important step in modeling and monitoring potential environmental and
human health impacts.
SBFs are a subcategory of non-aqueous drilling fluids (NAFs) which
do not easily disperse in the water column. The effects of NAF-cuttings
on benthic fauna may be categorized as being caused by: (1) physical
smothering; (2) the presence of potential toxic and hazardous
pollutants and biodegradation by-products (e.g., heavy metals,
aromatics, hydrocarbons, sulfides); and (3) the organic enrichment of
sediment which may produce anoxic conditions (Limia and Peresich,
1992). Field studies indicate that the responses shown by benthic
communities to cuttings discharges are the result of a combination of
these effects. Numerous field studies show that the most harmful
benthic effects are generally within 500 meters of development drilling
operations and within 250 meters of single well sites (Davies et al.,
1989).
Reducing the amount of initial base fluid on cuttings is beneficial
in promoting biodegradation of SBFs in the benthic environment.
Literature data make clear that the biodegradation of SBFs in the
environment is not simply an exponential decay (Getliff et al., 1997).
The half-life of the base fluid decreases as the initial concentration
of base fluid on cuttings decreases. Therefore, it is vital to minimize
the initial concentration of base fluid on cuttings discharged to
maximize the rates of biodegradation and seabed recovery.
Reducing the amount of initial base fluid on cuttings is also
beneficial in preventing the build-up of deleterious cuttings piles and
mats. A decrease in benthic individuals within the zone of maximum
cuttings deposition (i.e., cuttings piles and mats) is a result of
physical smothering and organic enrichment which produces anoxic
conditions and toxic sulfide biodegradation by-products (Daan et al.,
1996; Limia, 1996). A reduction of benthic individuals beyond the
immediate area of physical impact may be indicative of a toxic effect
(Davies and Kingston, 1992). The build-up of these harmful cuttings
piles and mats is controlled by several factors including the
conditions of the receiving waters (e.g., currents, distance from
discharge to seabed) and the retention of SBF on cuttings. A study of
cuttings piles in the North Sea found that piles of cuttings are found
predominantly at particular sites in the central and northern North
Sea, where water depths are greater, and currents less than, the
southern North Sea (Bell et al., 1998).
Results from laboratory experiments modeling typical ocean
conditions show that high NAF content on cuttings (i.e., high cuttings
retention values) lead to ``lumps'' of material, rather than separate
particles, which rapidly settle out (i.e., have high fall velocities)
to the benthic environment (Delvigne, 1996). Moreover, field results
show that cuttings are dispersed during transit to the seabed and no
cuttings piles are formed when SBF concentrations on cuttings are held
below 5% (Getliff et al., 1997; Hanni et al., 1998). Additionally,
cuttings discharged from cuttings dryers (with SBF retention values
under 5%) in combination with a sea water flush, hydrate very quickly
and disperse like water-based cuttings (Hanni et al., 1998).
Overall, lowering the percentage of residual drilling fluid
retained on cuttings increases the recovery rate of the seabed
receiving the cuttings (Getliff et al., 1997; Vik et al., 1996).
Therefore, limiting the amount of NAF content in discharged cuttings
controls: (1) The amount of NAF discharged to the ocean; (2) the
biodegradation rate of discharged NAF; and (3) the potential for NAF-
cuttings to develop cuttings piles and mats which are detrimental to
the benthic environment.
c. SBF on Cuttings Data Submitted by Industry. Subsequent to
proposal, SBF on cuttings data from various formations within the GOM
have been submitted by an industry workgroup, individual operators, and
by equipment vendors. These data characterize performance for a variety
of cuttings treatment technologies, including existing shaker
technologies and add-on equipment. Several comments on the February
1999 proposal also provided cursory information and data related to the
performance of new and existing solids control equipment and drilling
fluids. For example, one comment by Derrick Equipment Company described
SBF cuttings retention values in the range of 8 to 9% by weight for a
GOM well using a new shale shaker design. A comment by Baroid Drilling
Fluids stated that the lower viscosity of its new ester-based drilling
fluid will lead to greater recovery of its ester-based fluid from
cuttings.
Based on these data and other GOM data presented at proposal, EPA
has modeled and analyzed the cuttings retention performance of several
technologies. A summary of the revised models is presented in section
III.D. A summary of the analyses developed by EPA, including the
development of numeric guidelines and standards, is presented in
section IV.D. Detailed descriptions of the statistical methods, summary
statistics, overall averages, and percentiles associated with each
technology can be found in section III.C.(a) of the rulemaking record.
5. Industry Seabed Survey
Permits authorizing the discharge of SBF-cuttings are required to
meet (a) technology-based requirements, and (b) CWA section 403(c)
Ocean Discharge Criteria, or, in State waters of Cook Inlet, Alaska,
State water quality criteria. The February 1999 proposal described the
CWA 403(c) requirements and the seabed surveys EPA thinks would be
occurring, based on information available at that time to satisfy these
permit requirements. Today's notice updates the description
[[Page 21554]]
of the seabed survey efforts that industry is currently planning.
EPA understands that the industry is planning a cooperative effort
to address the CWA section 403(c) requirements in the GOM. Industry
representatives have told EPA that their cooperative seafloor study
would include a review of historical data on SBF usage on the shelf and
slope, and these data would be analyzed to select a representative
series of platforms.
The overall objective of the study is to assess the fate and
effects (physical, chemical, and biological) of discharged SBF-cuttings
at continental shelf (40 m to 300 m water depth) and deepwater (>300 m
water depth) GOM sites. Specific sub-objectives include determining the
thickness and areal extent of cuttings accumulations, determining the
temporal behavior of SBF concentrations in sediments, documenting the
physical-chemical sediment conditions, and determining whether a zone
of biological effect exists.
The study will include four cruises: a scouting cruise, a screening
cruise, and two sampling cruises. The purpose of the scouting cruise,
which is intended to take place in late spring of 2000, is to conduct a
preliminary physical survey of ten continental shelf sites to: (1)
assess the extent of cuttings accumulations; (2) assess the suitability
of each site for further sampling; and (3) guide further sampling
operations. The results of this cruise will be used to select five
continental shelf sites where the subsequent screening cruise will be
conducted.
During the screening cruise, five continental shelf sites and three
deepwater sites will be surveyed. The purpose of this cruise is to: (1)
Assess SBF concentrations and other sediment physical-chemical
conditions (e.g., oxidation-reduction profile, grain size, mineralogy,
metals, total organic carbon) at all eight sites; (2) test and refine
the proposed field and laboratory methods; and (3) make preliminary
benthic infaunal and sediment toxicity assessments at the five
continental shelf sites. Based on data acquired during this cruise,
sampling strata will be designated and platform sites will be
designated as primary or secondary. The three deepwater sites and three
of the five continental shelf sites will be primary sites, and the
remaining two continental shelf platforms will be secondary sites.
The sampling cruise will be similar to the screening cruise in
terms of physical-chemical analyses, but will include an increased
number of samples. Infaunal and sediment toxicity analyses will be
included at the three primary continental shelf sites. Sampling at the
two secondary continental shelf sites will be similar to that at the
primary sites, but the suite of analyses will not be as extensive
(e.g., it will not include metals, infaunal, or sediment toxicity
analyses).
EPA plans on using the data from the first survey to identify any
negative environmental effects from SBF discharges. If this data
becomes available in time, EPA might use that information in its
assessment of a controlled discharge option as compared to the NWQIs of
a zero discharge option. The current work plan for the seabed survey
can be found in section III.F.(a) of the rulemaking record.
6. Bioaccumulation
Several comments related to bioaccumulation were submitted to EPA
in response to the February 1999 proposal. In particular, one industry
commenter stated, without supporting data, that there is currently
sufficient data available amongst the various companies to show that
synthetic base fluids are not believed to bioaccumulate; further, that
most members of the industry groups maintain operations in the European
sector where bioaccumulation testing of base fluids has already been
conducted in compliance with the Harmonized Offshore Chemical
Notification Format (HOCNF) requirements. However, another commenter
stated, also without supporting data, that marine organisms higher in
the food chain are at significant risk due to bioaccumulation of SBF.
EPA is again requesting any data related to the potential of SBF to
bioaccumulate and the related chronic or toxic effects on higher level
organisms.
7. Technical Performance of Ester-based Drilling Fluids
In the proposed rule, EPA proposed its sediment toxicity and
biodegradation BAT limitations and NSPS based on product substitution
with C16-C18 Internal Olefins. Several commenters
on the February 1999 proposal and other industry stakeholders offered
data related to the technical and environmental performance of SBFs
(e.g., Limia and Peresich, 1992). Specifically, three commenters
provided data on the dynamic or kinematic viscosity of several SBFs
(e.g., isomerized olefins, esters). Baroid Drilling Fluids provided
data on its ``new ester'' with a dynamic viscosity comparable to a
C16-C18 IO. This drilling fluid manufacturer
claims that the new ester allows formulation of fluids which have cold
water performance comparable to, if not better than, some IOs (e.g.,
C16-C18 IO). Moreover, Baroid Drilling Fluids
noted that the price of esters-based drilling fluids in the GOM have
been reduced in half since their introduction and use in the GOM. EPA
has also received information that indicates that esters still remain
40-90% more expensive than IOs (Johnston, 2000a). EPA has also received
information that original and new ester technology continues to exhibit
higher viscosity that could result in higher downhole losses of whole
drilling fluids and higher cutting retention values (Friedheim and
Conn, 1996; Johnston, 2000a). Finally, EPA has received information on
the technical limitations (e.g., stability, elastomer swelling,
sediment toxicity, lack of field experience) of original and new esters
(Daan et al., 1996; Johnston, 2000a; Patel, 1998; Schaanning et al.,
1996).
Due to the potential for better environmental performance of ester-
based drilling fluids, EPA is considering basing the sediment toxicity
and biodegradation stock limitations and standards on original esters
instead of the proposed C16-C18 IO. EPA is also
considering sub-categorizing the regulation, based on the use of
esters. The different sub-categorization options under consideration by
EPA include: (1) limiting SBF discharges by setting numeric limitations
and standards based on ester-based drilling fluids when water
temperatures are above the practical limitations of esters; and (2)
limiting SBF discharges by setting numeric limitations and standards
based on C16-C18 IOs, thus allowing the discharge
of SBFs other than ester-based drilling fluids, when water temperatures
are below the practical limitations of esters.
EPA solicits comment on this subcategory approach, and again is
requesting any information and data related to the cost, technical
performance, potential environmental impacts (e.g., sediment and
aquatic toxicity, biodegradation), and frequency of industry use of
ester-based drilling fluids.
8. Subsea Pumping Systems
In the February 1999 proposal (64 FR 5495), EPA outlined an
innovative technology, generally referred to as ``subsea pumping,''
that may potentially outperform conventional drilling techniques in
very deepwater conditions (generally greater than 3,000 feet of water).
Subsea pumping is claimed by the developer to contribute
[[Page 21555]]
to a number of environmental, technical, and economic benefits.
The technology involves pumping the drilling fluid up a separate
riser by means of pumps at or near the seafloor. Rotary drilling
methods in a system using subsea pumping are generally similar to
conventional drilling methods, with the exception that the drilling
fluid and small cuttings (i.e., one-quarter inch) are boosted by one
or more pumps near the seafloor. By boosting the drilling fluid, the
adverse effects on the wellbore caused by the drilling fluid pressure
from the seafloor to the surface are eliminated, thereby allowing wells
to be drilled with as much as 50 percent reduction in the number of
casing strings generally required to line the well wall. Wells are
drilled in less time, including less trouble time.
The developer of this technology claims that subsea pumping can
significantly improve drilling efficiencies and thereby reduce the
volume of drilling fluid discharged, as well as reduce the non-water
quality effects of fuel use and air emissions. Because fewer casing
strings are needed, the hole diameter in the upper sections of the well
can be smaller, which reduces the amount of cuttings produced. Also,
the well bore will require fewer casing strings of smaller diameter,
resulting in a reduction in steel consumption. An additional benefit of
subsea pumping systems is the potential to extend the use of ester-
based fluids in the cooler, deeper waters of the GOM. Finally, subsea
system drilling may double or triple the reach of horizontal or
directional deepwater delineation sidetrack wells. Accordingly, this
may reduce the number of delineation wells needed to characterize a oil
and gas formation.
To enable the pumping of drilling fluids and cuttings to the
surface, about half of the drill cuttings, comprising the cuttings
larger than approximately one-quarter inch, are separated from the
drilling fluid and discharged at the seafloor since these cuttings
cannot reliably be pumped to the surface. With a currently reported
design, the drill cuttings that are separated at the seafloor are
discharged through an eductor hose at the seafloor within a 150-foot
radius of the well site. The drilling fluid, which is boosted at the
seafloor and transports the remainder of the drill cuttings back to the
surface, is conventionally processed.
Since the February 1999 proposal, the subsea pumping system
developer has reviewed the technology with staff from Minerals
Management Service (MMS) GOM Office, EPA Region 6, and EPA
Headquarters. In a letter dated May 24, 1999, MMS provided conditional
approval to the developer for using its subsea system for exploratory
and development wells in Outer Continental Shelf (OCS) waters. In a
letter dated July 30, 1999, EPA Region 6 concluded that discharges from
the developers subsea system are generally authorized by the general
permit for the western GOM (Permit No. GMG290000) provided that the
subsea discharges are monitored.
EPA Headquarters staff met with the developers of the subsea
pumping system on January 18, 2000, to discuss the technical and
environmental performance of the new technology. As part of the
meeting, the technology developers submitted a technical basis for
supporting their improved environmental, technical, and economic
performance. The developers also discussed with EPA Headquarters staff
their current plans to field test their subsea pump system solids
removal equipment offshore under atmospheric, not subsea, conditions.
The tests are scheduled to begin in May 2000 with data becoming
available in July 2000. The developers are planning to collect SBF
retention data as well as other data to determine the fractions and
concentrations of SBF discharged subsea. Notes from the January 18,
2000, meeting (including the technology developer technical report),
anticipated subsea pumping field test plans, and the two previously
mentioned letters are given in section III.B.(b) of the rulemaking
record.
The subsea system developer commented on the February 1999 proposal
and suggested that a definition for ``subsea pumping'' and a
clarification of subsea pumping discharge sampling and monitoring
requirements be added to this notice. In the supporting documentation
for the proposed rule, Development Document for Proposed Effluent
Limitations Guidelines and Standards for Synthetic-Based Drilling
Fluids and other Non-Aqueous Drilling Fluids in the Oil and Gas
Extraction Point Source Category (EPA-821-B-98-021), EPA stated that
for purposes of monitoring, samples of the subsea discharge can be
transported to the surface for analysis.
Based on the potential for reducing discharges to the environment
and as previously stated in the SBF Development Document, EPA is
considering different technology options for this subsea discharge.
These options include limiting the type of drilling fluids available
for use in subsea pumping systems; different monitoring and sampling
requirements for subsea discharges; subsea cuttings discharge dispersal
techniques; and cuttings retention requirements that are different from
surface discharges. EPA is requesting comments on the most appropriate
limitations and combination of limitations for these subsea discharges.
EPA is also requesting more information about the anticipated
percentage of future deepwater drilling operations that will employ
subsea pumping systems.
9. Cuttings Micro-encapsulation Systems
EPA Headquarters staff met with the developers of a new cuttings
management system, silica micro-encapsulation, on September 23, 1999,
to discuss the technical and environmental performance of the new
technology. Silica micro-encapsulation is a process by which the NAF
attached to the cuttings is physically encapsulated in an insoluble
matrix of amorphous silicate. More information on this technology is
given in section III.B.(b) of the rulemaking record.
The technology developer claims that the encapsulated oils do not
leach and do not biodegrade. The stated benefit of the micro-
encapsulation process is the ability to convert non-aqueous fluid
cuttings into water wet particles. Consequently, the non-aqueous fluid
cuttings behave in the water column similarly to water-based fluid
cuttings. The developer claims that this allows for maximum dispersion
of non-aqueous fluid cuttings. Finally, the developer claims that the
dispersion of the cuttings into a much greater area substantially
reduces the potential for benthic smothering and other toxic and
chronic environmental effects.
One issue related to this technology is the incompatibility of the
micro-encapsulation technology with the February 1999 proposal method
for determining the amount of drilling fluid that adheres to drill
cuttings. This method, Appendix 7 to Subpart A of Part 435-API
Recommended Practice 13B-2 (64 FR 5547), is designed to measure the
relative weights of liquid and solid components in a sample of wet
drill cuttings. The method uses a known weight of wet cuttings that is
heated in a retort chamber to vaporize the liquids contained in the
sample. The high heat of the retort analysis (approximately 930 deg.F)
can break down the micro-encapsulation coating and release the
previously sequestered oil droplet. Therefore EPA's proposed
requirements for minimizing oil on cuttings and use of the retort
method may eliminate the incentive to use the micro-encapsulation
technology.
[[Page 21556]]
EPA may consider different technology options for these micro-
encapsulated cuttings discharges. These options include product
substitution of only certain types of drilling fluids available for use
in micro-encapsulating systems; different monitoring and sampling
requirements for micro-encapsulated discharges; different toxicity
tests; and different cuttings retention requirements. Specifically, EPA
is proposing that this technology may be more beneficial in combination
with other technologies (e.g., product substitution, add-on solids
removal equipment) to assist operators in meeting site specific CWA
section 403 NPDES permit requirements. As stated previously, switching
to less toxic and more biodegradable drilling fluids, reducing the oil
on cuttings, and increasing the dispersion of the cuttings is
instrumental in preventing build-up of cuttings piles and reducing
impacts to the benthic environment. Use of this micro-encapsulation
technology to promote cuttings dispersion and further sequester the oil
on cuttings, after use of new solids control equipment, may provide
addition environmental protection. EPA is requesting comments and
information related to the environmental, technical, and economic
performance of this and similar micro-encapsulation technologies and
the incentive/disincentive issue with respect to the proposed retention
limitation and standard using the retort method as the compliance test
method.
B. EPA Data Collection Since Proposal Publication
1. Sediment Toxicity Test Results
Because of the limited data available for the proposal on the
sediment toxicity of both the base fluids and whole drilling fluid
systems, EPA has begun a study using sediment toxicity test methods to:
(1) determine the toxicity of various base fluids and whole synthetic
fluid drilling systems on amphipods for purposes of selecting fluids
that represent the appropriate level of technology; and (2) evaluate
possible sediment toxicity compliance method options. The initial tests
conducted in December 1999 at the EPA Gulf Breeze Laboratory evaluated
the sediment toxicity of three synthetic base fluids compared to diesel
and have consisted of 96-hour and 10-day exposure tests with an IO, a
LAO, and an ester as the base fluids as compared to No. 2 diesel oil.
At the same time, EPA's contract laboratory, Battelle, also conducted
initial sediment toxicity tests on mineral oil and paraffin in addition
to the same three synthetic base fluids evaluated by the EPA Gulf
Breeze Laboratory.
EPA is currently conducting tests to determine influences of whole
fluid compositions and crude oil contamination on the sediment toxicity
of an internal olefin (IO), linear alpha olefin (LAO), and ester.
Current and previous sediment toxicity tests conducted by EPA have used
the ASTM E1367-92 sediment toxicity method supplemented with a sediment
preparation procedure (see 64 FR 5536: Appendix 3 to Subpart A of Part
435). Table II.B.1.1 summarizes the sediment toxicity data that EPA has
collected since proposal.
Table II.B.1.1: EPA-Collected LC50 Sediment Toxicity Data With Various Drilling Base Fluids for Two Different
Time Periods
----------------------------------------------------------------------------------------------------------------
95% Confidence
Drilling base fluid LC50 (mg/Kg) interval
----------------------------------------------------------------------------------------------------------------
EPA Gulf Breeze Laboratory--Generated Data
----------------------------------------------------------------------------------------------------------------
96-Hour Test................................. Internal Olefin................ ND NA
Linear Alpha Olefin............ 750 677-930
Ester.......................... 10812 9138-12793
Diesel......................... 463 426-505
10-Day Test.................................. Internal Olefin................ 660 423-1029
Linear Alpha Olefin............ 419 350-502
Ester.......................... ND NA
Diesel......................... 199 171-232
----------------------------------------------------------------------------------------------------------------
EPA Contract Laboratory (Battelle)--Generated Data
----------------------------------------------------------------------------------------------------------------
96-Hour Test................................. Internal Olefin................ >8000 NA
Linear Alpha Olefin............ 2921 2260--3775
Ester.......................... 7686 7158--8253
Mineral Oil.................... 436 485--391
Paraffin....................... 2263 1936--2644
10-Day Test.................................. Internal Olefin................ 2530 2225--2876
Linear Alpha Olefin............ 1208 1089--1339
Ester.......................... 4275 3921--4662
Mineral Oil.................... 176 163--190
Paraffin....................... 1151 1038--1276
----------------------------------------------------------------------------------------------------------------
Method Reference: EPA February 1999 Proposal (64 FR 5488).
ND--Not determined; NA--Not applicable.
In addition, EPA is assessing the toxicity potential for
degradation by-products. EPA has some information related to SBF by-
products (Candler et al., 1995; Getliff et al., 1997; Johnston, 2000a).
These data show that aerobic and anaerobic degradation mechanisms for
many SBFs (especially linear hydrocarbons) produce by-products that
include biodegradable alcohols and fatty acids. Some SBFs, such as
linear paraffins, are still the subject of some debate as to their
exact mode of biodegradation and associated by-products under anaerobic
conditions. In addition, ester-based drilling fluids by-products (e.g.,
alcohols) may exhibit toxic effects in the water column (Johnston,
2000a). EPA solicits comments and data on whether there are any known
persistent or toxic by-products created by the biodegradation of
synthetic base fluids. This information will allow EPA to assess the
[[Page 21557]]
overall environmental impact of using synthetic base fluids.
Finally, as originally stated in the February 1999 proposal (64 FR
5491), EPA may require additional or alternative controls as part of
the BAT/NSPS discharge options based on method development and data
gathering subsequent to today's notice: (1) Maximum sediment toxicity
of drilling fluid at point of discharge (minimum LC50, mL
drilling fluid/kg dry sediment by 10-day sediment toxicity test or
amended test); (2) maximum aqueous phase toxicity of drilling fluid at
point of discharge (minimum LC50 by Suspended Particulate
Phase (SPP) test (see Appendix 2 of Subpart A of Part 435) or amended
SPP test); and (3) maximum potential for bioaccumulation of stock base
fluid (maximum concentration in sediment-eating organisms). In
particular, EPA is interested in controlling the toxicity of SBFs in
the sediment and the water column and may require both a sediment
toxicity test and an aqueous phase toxicity test to assess overall
toxicity.
A more complete review of the sediment toxicity procedures and data
can be found in section III.B.(a) of the rulemaking record.
2. Biodegradation Test Results
Because of the limited data available for the proposal on the
biodegradation of SBFs, EPA has begun a study using the solid phase
biodegradation test, proposed in February 1999, to: (1) determine the
biodegradation of various synthetic base fluids for purposes of
selecting fluids that represent the appropriate level of technology;
and (2) evaluate possible biodegradation compliance options. This
project began in January 2000 and results are anticipated to be
finalized in March 2000. Table II.B.2.1 summarizes the data collected
to date. A more complete review of these procedures and data can be
found in section III.B.(a) of the rulemaking record.
Table II.B.2.1: EPA Solid Phase Biodegradation Test
----------------------------------------------------------------------------------------------------------------
Percent loss relative to day 0
-----------------------------------------------------------------------------
Poly Linear
Ester Paraffin (alpha) Mineral oil Internal alpha
(percent) (percent) olefin (percent) olefin olefin
(percent) (percent) (percent)
----------------------------------------------------------------------------------------------------------------
Day 0............................. 0 0 0 0 0 0
Day 14............................ 53 21 22 20 9 8
Day 28............................ 60 19 25 21 18 16
----------------------------------------------------------------------------------------------------------------
Method Reference: EPA February 1999 Proposal (64 FR 5488).
3. EPA Engineering Data Collection Activities
During the week of October 25, 1999, EPA staff traveled to Texas
and Louisiana to observe onshore and offshore equipment used for
treating and disposing of SBF and SBF-cuttings. Highlights of the
onshore portion of the field trip include visits to an operating
cuttings dryer unit, a fracture slurry injection facility, and a barge
facility on the GOM intercoastal waterway.
Offshore highlights included visits to two oil and gas drilling
operations to observe waste management and pollution prevention
practices. EPA staff also observed working solids control equipment
including cuttings dryers. These cuttings dryers are designed to
recover more SBF from cuttings generated by primary and secondary shale
shakers. This field trip also included an all day meeting with cuttings
dryer equipment vendor representatives and members of industry. Field
notes from the site visit and minutes of the all day meeting can be
found in section III.B.(a) of the rulemaking record.
EPA also obtained information from the industry primarily related
to the per-well aspects of drilling with SBF in three subject areas:
(1) Drilling operations; (2) solids control equipment and systems; and
(3) costs, in order to better understand current and emerging SBF and
SBF-waste management practices.
Finally, EPA collected information from MMS regarding accidental
spills of OBFs and SBFs. Spills can release small and large quantities
of drilling fluid. In particular, undetected leaking lines can release
several hundred barrels of drilling fluid while accidental riser
disconnects can release several thousand barrels of whole drilling
fluid into the environment. Specifically, EPA is interested in: (1) the
occurrences of accidents and events that can cause the release of OBF
and SBF whole drilling fluid (e.g., riser disconnects, blow-outs,
shallow water flow problems); (2) the number of these accidents and
events over the past five years for each MMS region (Alaska,
California, GOM); (3) the location of these events (i.e., shallow or
deepwater); and (4) the volumes associated with these accidents and
events. Preliminary information is that there have been several spills
of OBFs over the past five years, but most were small volumes. In
addition, MMS data identifies three events, including two riser
disconnects, that resulted in significant releases of SBFs into the
environment for the months of January and February 2000. Under the zero
discharge option EPA assumes that all operators requiring NAF will
switch to OBFs. As the toxicity of OBFs is greater than SBFs, EPA will
use this spill data as a factor in supporting the selection of a
controlled discharge option in the final rule.
A more complete review of the EPA collected engineering data can be
found in section III.B.(a) of the rulemaking record.
4. Non-Water Quality Environmental Impacts (NWQI)
The additional cuttings retention data submitted to EPA (see
section II.A.4) were used in the revision of the engineering models
that form the basis for all per-well numeric compliance analyses. Based
on changes in the engineering models described below in section III.A,
EPA revised the numeric NWQIs of fuel usage, air emissions, and solid
waste generation.
The U.S. Department of Energy (DOE) collected information about
currently operating onshore commercial disposal facilities that are
permitted to receive offshore drilling wastes. The Argonne National
Laboratory (DOE) contacted State officials in Louisiana, Texas,
California, and Alaska to obtain this information. EPA also identified
a list of Louisiana commercial non-hazardous oilfield wastes (NOW)
facilities from the Louisiana Department of Natural Resources.
EPA also contacted Alaska, Texas, and Louisiana regulatory agencies
to obtain current information concerning
[[Page 21558]]
management of offshore and coastal exploration and production wastes.
The Texas Natural Resource Conservation Commission (TNRCC) provided
permit information and waste disposal limitations for the Texas
fracture slurry injection facility visited by EPA staff (see section
II.B.3). The Alaska Oil and Gas Conservation Commission (AOGCC)
provided information related to Cook Inlet formation disposal of
drilling fluids and cuttings.
EPA also reviewed two papers that detail operations of a large
Louisiana onshore fracture slurry injection facility operated by
Chevron for Naturally Occurring Radioactive Materials/Non-Hazardous
Oilfield Wastes (NORM/NOW) (Baker et al., 1999a; Baker et al., 1999b).
Currently, this Chevron facility is limited by its permit to only
handle exploration and production wastes from Chevron GOM operations.
EPA also contacted Cook Inlet, Alaska, operators to identify the
current and projected use of SBF and the most current waste management
options for drill cuttings and fluids. Operators noted that few wells
were being drilled with SBF due to NPDES general permit prohibition of
SBF discharges. Furthermore, Cook Inlet operators noted that the only
drill cuttings and fluid management options available to them are land
disposal of cuttings or grinding and injection of the cuttings back
into the formation. Land disposal of OBF-and SBF-cuttings was
identified as cost prohibitive.
In considering all options for management of non-aqueous fluids
(NAF) and NAF-cuttings, EPA is also identifying possible scenarios for
cross-media contamination. In particular, EPA is trying to identify
former NOW treatment, storage, or disposal facilities that are now
CERCLA (or ``Superfund''), RCRA Corrective Action, or State lead
cleanup sites. An initial search by EPA identified several such sites
including several sites around Abbeville, Louisiana. Accordingly, EPA
is requesting additional information related to other sites (Superfund,
RCRA Corrective Action, or State lead) that have been contaminated with
NOW from offshore operations.
The findings of current onshore waste management options and former
NOW facilities that are now cleanup sites outlined in this section are
presented in section III.B.(a) of the rulemaking record.
Also subsequent to the proposal, EPA has monetized the human health
benefits associated with volatile organic compound (VOC), particulate
matter (PM), and sulfur dioxide (SO2) emission reductions
for the two controlled discharge options. The valuation methodology is
presented in section III. The results of these revisions are presented
in section IV below.
5. Economic Data (including Deep Water Model Wells)
EPA collected information from industry regarding model deepwater
project costs for the Gulf of Mexico, produced water treatment costs,
wellhead oil and gas prices, and drilling activity forecasts. A summary
of the data is provided in section III.G of the rulemaking record.
EPA is developing a methodology to examine the economic and
financial impacts of the SBF guidelines on both existing and new
deepwater oil and gas projects in response to comments from industry
that these projects are vastly different from the projects analyzed as
part of the Offshore Oil and Gas Effluent Guidelines economic analysis.
At proposal, EPA relied on the results of that latter analysis showing
Gulf of Mexico projects to be only minimally affected by even the most
stringent drilling waste option (the zero discharge option). Because of
the unique nature of deepwater projects and because of their greater
distance from shore, industry believes deepwater projects need to be
evaluated for economic impacts resulting from options considered for
the rule.
EPA is thus developing a computer model similar to the one used for
the Offshore rule, and also nearly identical to the one developed for
the Main Pass operations in the Gulf of Mexico investigated during the
Coastal Oil and Gas Effluent Guidelines rule. The general structure of
the model is based on the Main Pass Model with a few minor variations
[for example, severance tax is not an issue, so this line item is not
used (see Economic Impact Analysis of Final Effluent Limitations
Guidelines and Standards for the Coastal Subcategory of the Oil and Gas
Extraction Point Source Category, Appendices A and B, EPA-821-R-96-
022)].
The major differences of this model compared to the Main Pass model
are the inputs. EPA investigated a number of deepwater projects for use
as model projects. These projects included all currently operating
projects, as well as a number that should come on line shortly. Over 30
projects fit this description. From these initial projects, EPA
selected as many as possible to use in modeling deepwater projects.
Data availability was the primary criterion used in selecting the model
projects. EPA selected all deepwater projects for analysis that
operated in 1998 and that had original proved reserves data available
in public documents. The most recent publicly available documents on
proved reserves are those provided by MMS on its website and these
documents are current through December 31, 1996. Proved reserves are
used to distinguish the relative size of projects, since the indication
of the ultimate size of a project is reserves, not necessarily the
current production (new projects that have not completed the maximum
number of wells that would be productive at any one time would end up
classified as smaller than they will eventually become). Size of
project is important, since results will be reported over a group of
projects (i.e, results for small, medium, and large projects) rather
than project-by-project. Size of reserves also allows EPA to determine
how many wells might be drilled at a project over time.
Using the data availability criterion, EPA reduced the number of
projects that can be modeled to twenty. One project did not operate in
1998, and the others either have not yet started producing, or are so
new that original proved reserves had not been calculated for them in
December 1996. The twenty projects include four small projects
(original proved reserves of 10 million barrels of oil equivalent (BOE)
or less, eight medium-size projects (original proved reserves
approximately between 10 million and 100 million BOE), and eight large
projects (original proved reserves over 100 million BOE). BOE for each
project is the sum of the oil (42 gal. oil = 1 BOE) and natural gas
(1,000 scf = 0.178 BOE). To model new projects, however, five of the
twenty projects were dropped from the analysis as being too old or as
using construction technologies unlikely to be used in the future. The
remaining 15 projects generally had been producing less than 5 years in
1998.
Other information was obtained either from industry contacts or was
based on data developed by EPA and used either in analyzing the
economic impacts of the Offshore or Coastal Subcategory Oil and Gas
Effluent Guidelines. Section III.G of the rulemaking record provides
data on projects used to model deepwater projects as well as
assumptions and sources of data for the oil and gas financial model.
6. Environmental Assessment Data
a. Water and Sediment Quality Criteria. Subsequent to conducting
water quality analyses for the Environmental Assessment (EA) for the
proposed rule, EPA published its revised recommended water quality
criteria for arsenic (deletion of human
[[Page 21559]]
health criterion); copper (increased from 2.4 g/l to 4.8
g/l and 3.1 g/l for acute and chronic aquatic
community criteria, respectively); mercury (increased from 0.025
g/l to 0.94 g/l for chronic aquatic community
criterion), and phenol (deletion of human health criterion) in the
Federal Register (December 10, 1998; 63 FR 68354). In addition Alaska
promulgated new State water quality standards for toxic pollutants on
May 27, 1999 (see Alaska Administrative Code, Title 18, Chapter 70 or
section III.F.(a).2 of the rulemaking record). These deletions and
corrections are incorporated in revisions to the analyses of water
column, pore water, and sediment guidelines quality outlined in the
February 1999 Environmental Assessment Document (EPA-821-B-98-019).
b. Dilution Data. The same model used in the February 1999
proposal, Brandsma (1996), was used in this notice to estimate the
concentration of synthetic fluids within the water column for
assessment of attainment with recommended water quality criteria. These
revised dilution calculations are used for the water column water
quality analyses and for the calculations of exposure concentrations
for the health benefits analyses.
c. Review of the Seabed Surveys. In response to comments and new
data received, EPA revised the Seabed Survey portion of the
Environmental Assessment. All of the studies presented in the original
EA were re-analyzed to correct omissions and errors identified by
commenters. One additional study was submitted by a commenter, BP
Amoco, entitled Deepwater Sampling at a Synthetic Drilling Mud
Discharge Site on the Outer Continental Shelf, Northern Gulf of Mexico
(Fechhelm et al., 1999). EPA reviewed this study which investigated the
deepwater benthic effects of a SBF (90% linear-alpha olefins and 10%
esters) discharge and added relevant data to the EPA EA analyses.
EPA EA models use a mean of SBF sediment concentrations from
various seabed surveys found in the literature. EPA updated the mean
SBF sediment concentration (at 100m from the modeled discharge) from
13,892 mg/kg to 14,741 mg/kg to incorporate new data identified in the
BP Amoco benthic study.
d. Receipt of the United Kingdom Offshore Operators Association
(UKOOA) Research Reports. In June 1998, UKOOA, supported by the Oil
Industry International Exploration and Production Forum (E & P Forum)
and in co-operation with the Norwegian oil association (OLF), launched
an initiative to tackle the historical legacy of accumulated drill
cuttings beneath offshore installations in the North Sea. Many of these
North Sea cuttings piles were generated from the practice of
discharging cuttings from multiple wells into a single deposition
point. These drilling operations also used OBFs which contain a high
PAH content. The ultimate goal of the UKOOA research is to identify the
best environmental practice and the best techniques available for
managing these accumulations.
Immediately prior to publication of this notice, EPA acquired
several reports related to the UKOOA industry research activities in
the North Sea. These UKOOA reports are based on literature review and
field studies. Specifically, EPA received UKOOA reports related to
cuttings pile toxicity, faunal colonization of cuttings piles,
contaminant leaching from drill cuttings piles, and natural degradation
and estimated recovery time-scale.
EPA plans to incorporate the relevant major findings and
conclusions into the final EPA SBF Environmental Assessment document
and analyses. Specifically, EPA plans on using relevant North Sea data
in assessing its method alternatives for determining sediment toxicity,
biodegradation, and bioaccumulation. Moreover, EPA plans to incorporate
relevant data from North Sea field studies into assessing the various
discharge and zero discharge options for SBF-wastes. Section III.B.(a)
of the rulemaking record gives summary of the data collected to support
the EPA SBF Environmental Assessment.
III. Revised Models
A. Revised Engineering Models
1. Large Volume Discharges
Through discussions with stakeholders and the October 1999 site
visits to offshore drilling operations, EPA has obtained more
information about current and emerging solids control practices.
Regarding current practices, EPA has re-evaluated its model of the
``standard'' or ``baseline'' solids control system. The baseline model
presented in the February 1999 proposal consisted of a primary shale
shaker that discharges cuttings and a secondary shale shaker that
discharges fine-particle cuttings (referred to as ``fines'').
Since proposal, EPA learned that cuttings are discharged from both
primary and secondary shale shakers, and that fines are generated from
additional equipment such as high-speed shale shakers (called ``mud
cleaners'') and centrifuges whose purpose is to treat the drilling
fluid by removing undesirable fine solids. These fines were reported by
one industry commenter on the February 1999 proposal to have SBF
cuttings retention values as high as 20 percent by weight.
Therefore, the revised baseline model consists of primary and
secondary shale shakers, plus a ``fines removal unit'' that may be
either a mud cleaner or a centrifuge. Discharges from the baseline
model system consist of cuttings from the primary shale shaker,
cuttings from the secondary shale shaker, and fines from the fines
removal unit. Based on data provided in the spreadsheets submitted by
industry representatives, the baseline model volume fractions of the
three discharges, expressed as percentages of the total volume of all
cuttings discharged from the baseline model well, are 78.5% for the
primary shakers, 18.5% for the secondary shakers, and 3% for the fines
removal unit.
EPA received sufficient additional cuttings retention data from GOM
sources to re-evaluate the discharges of these three units and to
calculate a revised baseline long-term average retention value of 11.4%
by weight of SBF on cuttings. Despite the revision of the retention
data and the model baseline system, the revised long-term average
retention value is only slightly higher than the 11% originally
calculated for the proposal, providing further confidence in the
accuracy of the baseline model and associated data.
Since the February 1999 proposal, the GOM offshore drilling
industry has increased its use of ``add-on'' cuttings drying equipment,
``cuttings dryers,'' to reduce the amount of SBF adhering to the
cuttings prior to discharge. Specifically, over twenty GOM SBF well
projects utilized these cuttings dryers in the recent past to reduce
the amount of SBF discharged (Johnston, 2000a). Current data available
to EPA indicates that these cuttings dryers can operate consistently
and efficiently when properly installed and maintained. Specifically,
vendor supplied data associated with these cuttings dryer deployments
suggest that the overall cuttings dryer downtime (i.e., time when
cuttings dryer equipment is not operable) is approximately one percent
of the overall operating time (Johnston, 2000a).
At the time of the February 1999 proposal, EPA had obtained
retention data from only one such add-on technology, namely the Mud-10
vibrating centrifugal dryer. Since then, EPA has observed the operation
of another drying technology, generally
[[Page 21560]]
referred to as a vertical centrifuge dryer. The vertical centrifuge
dryer unit serves the same purpose and occupies the same location in
the treatment train as the Mud-10 unit. EPA generically refers to the
Mud-10 unit and the vertical centrifuge dryer as the ``cuttings
dryer.''
Immediately prior to publication of this notice, EPA also received
limited cuttings retention data from a third type of add-on equipment
referred to as a ``squeeze press'' mud recovery unit. When installed,
the squeeze press mud recovery unit occupies the same location as the
above-mentioned cuttings dryers and serves to reduce the amount of SBF
adhering to the cuttings prior to discharge. The specific data for the
squeeze press were received too late to include in the statistical
determination of retention values for today's notice. However, these
data are included in the public record for the rule and EPA solicits
comments on them (Johnston, 2000b). These data, along with additional
retention data received from other industry sources, will be evaluated
and included in the appropriate engineering and statistical analyses
used to support the cuttings retention limitation in the final rule.
Most cuttings dryer applications include a centrifuge or mud
cleaner in the treatment train, to serve the same purpose as the fines
removal unit in the baseline system (i.e., to remove undesirable fine
solids from the drilling fluid recovered by the cuttings dryer).
Therefore, EPA's revised model of BAT/NSPS-level solids control
includes primary and secondary shale shakers that send all their
cuttings to a cuttings dryer, followed by a fines removal unit. There
are two discharges from the BAT/NSPS-level model solids control system:
one from the cuttings dryer and one from the fines removal unit. The
BAT/NSPS-model volume fractions of the two discharges, expressed as
percentages of the total volume of all cuttings discharged from the
BAT/NSPS-model well, are 97% for the cuttings dryer and 3% from the
fines removal unit. EPA, however, solicits more volume fraction data to
further refine its baseline and BAT/NSPS discharge models.
For today's notice, EPA evaluated two different scenarios based on
the above BAT/NSPS-model solids control system. The first scenario
assumes that both the cuttings from the cuttings dryer and the fines
from the fines removal unit are discharged. This first BAT/NSPS-model
scenario is essentially unchanged from the BAT/NSPS-model presented at
the February 1999 proposal. The long-term average SBF cuttings
retention value for this first BAT/NSPS-model scenario is 2.68% by
weight. This new long-term average cuttings retention value is lower
than the February 1999 proposal BAT/NSPS-model long-term average
cuttings retention value of 7% by weight. The difference is
attributable to the replacement of the North Sea data with data from
recent GOM drilling projects. The second BAT/NSPS-model scenario
assumes that only the cuttings are discharged, and the fines, which
represent a comparably smaller volume of waste, are retained for zero
discharge via hauling to shore for land-based disposal. Therefore, the
long-term average cuttings retention value for this second BAT/NSPS-
model scenario is equal to the retention value for the cuttings dryer,
2.45% by weight.
At this time, EPA thinks that data from the GOM are adequate to
represent field conditions throughout the United States. These data
include variations in geological formations, drilling conditions, and
rates of penetration. However, EPA is still requesting cuttings
retention data from offshore and coastal drilling operations that use
SBFs. In particular, EPA is requesting SBF cuttings retention data from
United States offshore or coastal oil and gas exploration and
production facilities operating outside of the GOM. If EPA does not
receive additional non-GOM data, EPA is comfortable with applying the
GOM data to other offshore and coastal regions in the United States.
The analyses for compliance costs, pollutant loadings, and numeric
non-water quality environmental impacts are based on the volumes of
waste solids and adhering drilling fluid estimated to be discharged
from each of four model wells. The model wells are defined in terms of
four categories: deep water (i.e., 1000 ft) development,
deep water exploratory, shallow water (i.e., 1000 ft) development and
shallow water exploratory. While the model well sizes are unchanged,
the volumes of adhering drilling fluid were revised based on the
revised retention values. Based on further communication since the
February 1999 proposal with industry about current and future drilling
plans in the GOM, California, Alaska, and North Carolina, the numbers
of each type of model well drilled annually are also unchanged. EPA is,
however, requesting more data detailing the annual number of shallow
water and deep water SBF-wells. EPA is also requesting data on the
conditions and frequency when SBFs are chosen over water-based drilling
fluids, when both drilling fluids are technically acceptable for
drilling (i.e., some shallow water wells).
EPA also re-evaluated the zero-discharge option using the updated
baseline retention data. The only notable change in the approach to the
zero-discharge analysis is the distribution of wells using land-based
disposal versus wells using onsite injection. The original analysis
assumed that 80% of the affected wells would use land-based disposal
and 20% would use onsite injection. While this assumption remains
applicable to shallow water wells, EPA learned from industry sources
that onsite injection is currently less applicable to deep water wells,
due to limitations of mechanical equipment, geology, and well
placement. Therefore, the zero discharge analysis now assumes that all
deep water wells will haul cuttings to shore for land-based disposal.
As zero discharge remains a proposed management option, EPA is
requesting additional data and information related to what drilling
fluids and waste management practices operators will likely use and the
overall impact on the annual number of drilling projects if EPA selects
the zero discharge management option for SBFs.
The current engineering cost analysis also assigns the installation
and downtime costs to every well. However, EPA recognizes that it is
likely that multiple wells would be drilled from a single installation,
thereby reducing the effect of the installation cost on each well's
total compliance cost. It is also likely that some drilling rigs will
purchase and permanently install cuttings dryers and fines removal
units, further reducing the effect of installation costs on any one
well. The data EPA has gathered to date are limited in this regard.
Therefore, EPA requests additional information pertaining to the
average number of wells drilled annually with SBF per platform, and the
number of platforms capable of permanently installing cuttings dryers
and fines removal units.
Details of the revised engineering models are provided in a
technical support document in section III.C.(b) of the rulemaking
record.
2. Small Volume Discharges
In its study of current solids control practices, EPA learned that
SBF is controlled with zero discharge practices at the drill floor, in
the form of vacuums and sumps to retrieve spilled fluid. EPA also
learned that approximately 75 barrels of solids coated with SBF can
accumulate in the dead spaces of the mud pit, sand trap, and other
equipment in the drilling fluid circulation system. Current practice is
to either wash these solids out with water for overboard
[[Page 21561]]
discharge, or to retain the waste solids for disposal.
Since zero discharge practices at the drill floor during drilling
are the current practice, no additional costs were considered for
controlling spills of SBF at this location. However, EPA did
investigate options for controlling the discharges of accumulated
solids generated by equipment cleaning procedures at the end of a
drilling project. Assuming that every drilling project generates
approximately 75 barrels of these small-volume waste accumulated
solids, the costs vary only by: (1) geographic region; and (2) the
numbers of wells in each regulatory scenario. EPA used the line-item
costs developed for the zero discharge compliance cost analysis to
calculate per-well and total costs for existing and new sources to
dispose of accumulated solids via hauling to land based disposal
facilities. The industry-wide costs resulting from this analysis are
given below in section IV, Table IV.A.2.1.
B. Revised Economic Models
EPA plans to use the same methodologies in analyzing firm-level
impacts used at proposal, but will update information to include at a
minimum 1998 financial data as well as 1997 financial data. The year
1998 was not a good year for the oil and gas industry, whereas 1997 was
a good year, so these two years should provide some sense of the
volatility of the industry. EPA still expects that the impact on firms
will be minimal, even given the difficult year the industry had in
1998. Additionally, EPA will use the same methodology for the small
business analysis that was used at proposal. EPA does not expect the
analysis to change significantly from proposal because: (1) Costs have
not changed substantially; (2) only a few small operators are believed
to be using SBFs; and (3) very few wells are drilled by small operators
in a year.
Instead of relying on the Offshore Oil and Gas Effluent Guidelines
EIA to provide a sense of financial impact at the facility level,
however, EPA is changing the approach to allow deepwater projects to be
modeled financially, as discussed in section II.
At the time of this notice, EPA believes that economic impacts from
even the most stringent option (i.e., zero discharge of SBFs) will have
only minimal influence on most deepwater projects. However, as zero
discharge remains a proposed management option, EPA is requesting
additional data and information related to whether or not the selection
of the zero discharge management option for SBFs will affect the
overall annual number of drilling projects in deep and shallow waters
in the United States. Further technical details are presented in
supporting documentation in section III.G of the rulemaking record,
which discusses potential impacts on typical, or average, deepwater
projects.
However, because averages can obscure the effects at the most
vulnerable projects, EPA will be looking closely at the potential for
option costs to cause any measurable impacts at projects that do not
conform to the parameters of the average project using the financial
model. Although model outputs will be reported in the aggregate by
project size, each individual project will be represented in the model
inputs to allow EPA to identify impacts more precisely.
The projects likeliest to show some potential for impact are the
smallest projects (both existing and new, if the existing projects
continue to drill), the oldest existing projects (such as Lena and
Cognac, which have produced over 80 percent of their original proved
reserves as of 1996), or very marginal projects. Because any project
could be marginal when all the factors are accounted for, even the
relatively small cost of the SBF rule could have an impact on one or
more projects, although, at this time, EPA believes this possibility is
small.
C. Revised Environmental Assessment (EA) Models
Revisions to the regulatory options such as the revised retention
on cuttings values and the addition of another controlled discharge
option has resulted in changes in the SBF environmental assessment. The
retention on cuttings affects both the pollutant loadings and the
volume of waste discharged, thereby affecting the water quality,
sediment quality and human health impacts. EPA has therefore re-
iterated the various EA analyses and the results are presented in
section IV below. There are, however, no changes in the EA models as
outlined in the February 1999 proposal and the Environmental Assessment
Document (EPA-821-B-98-019).
The models developed to calculate the NWQIs of air emissions, fuel
usage, and solid waste generation have been revised parallel to the
revisions in the engineering models described in section III.A. The
revised waste volumes that resulted from new retention data required
adjustments of such NWQI model elements as numbers of boat trips,
cuttings boxes, and crane lifts. An additional NWQI model was developed
for the BAT/NSPS discharge scenario based on 2.45% retention on
cuttings. For both of the discharge scenarios, the energy requirements
for the cuttings dryer and fines removal units were revised to reflect
the newer technologies now accounted for in the engineering models.
Finally, the zero discharge model was changed according to the new
finding that deep water wells cannot readily utilize onsite injection
and, rather, haul cuttings to shore-based disposal facilities.
Also subsequent to the February 1999 proposal, EPA monetized the
human health benefits for the two controlled discharge options
associated with reducing volatile organic compound (VOC), particulate
matter (PM), and sulfur dioxide (SO2) emissions. The
valuation methodology used to conduct the monetized benefits analysis
is presented in Environmental Assessment of the Final Effluent
Limitations Guidelines and Standards for the Pharmaceutical
Manufacturing Industry (EPA-821-B-98-008). The results of these
revisions are presented in section IV below.
D. Revised Models for the Performance of Cuttings Treatment
Technologies
As stated in the February 1999 proposal, EPA is considering setting
limitations and standards for the percent retention of synthetic-based
drilling fluids on cuttings that may be discharged from the cuttings
dryer and fines removal technologies. EPA received cuttings retention
data after the February 1999 proposal (see section II.A.4). This
section of the notice outlines the revisions made to the statistical
models for the performance of cuttings treatment technologies. A
summary of the output of these revised models with new data is given in
section IV.D.
EPA analyzed cuttings treatment data presented at proposal using
well averages where each cuttings retention value is weighted by an
associated hole volume. Since publication of the proposed statistical
support document in February 1999, EPA incorporated four changes into
the statistical methods used to estimate summary statistics which
support the development of numeric limitations and standards for the
retention of synthetic-based drilling fluids on cuttings. These changes
are: (1) Imputation of volume-weighted factors for zero and negative
drilling intervals; (2) correction to the estimator for volume-weighted
variances; (3) the addition of uniformly-weighted summary statistics;
and (4) consideration of the 99th percentile rather than the 95th
percentile for the development of numeric limitations and standards for
the maximum well
[[Page 21562]]
averaged percent retention of SBF on cuttings.
EPA generally estimated the volume of cuttings using the drilling
interval and the pipe diameter immediately preceding a retention
measurement. However, at times, the drilling intervals are reported as
zero or negative. A negative drilling interval indicates that the drill
pipe has been pulled up to facilitate drilling in a new direction. EPA
excluded negative interval data from the proposal. In this report,
negative drilling intervals are treated in the same fashion as zero
drilling intervals.
At proposal, EPA estimated weighted variances as if the weights
could only take on a small number of possible values. However, those
weights are based on the volume of cuttings associated with a
particular drilling interval and that volume may take on infinitely
many values. In this report, EPA estimated weighted variances as if the
weights could only take on infinitely many values.
Under the assumption that the retention on cuttings increased with
the depth drilled, EPA proposed numeric guidelines and standards using
retention values weighted by the volume drilled. However, the graphics
showing percent retention versus depth drilled do not indicate that
this is true (EPA, 2000). Therefore, EPA has added the use of
uniformly-weighted summary statistics as part of EPA's statistical
models. With no apparent relationship between depth drilled and percent
retention, the uniformly-weighted summary statistics are more
appropriate. Basing numeric guidelines and standards on a single type
of measurement, as opposed to a combination of multiple types of
measurements, will reduce the measurement variability associated with
the guidelines and standards. Additional benefits of setting numeric
guidelines and standards based on uniformly-weighted summary statistics
include eliminating the need to: (1) Calculate the length of interval
drilled; (2) impute volumes where zero or negative intervals exist; and
(3) use unusual variance estimation procedures. EPA prefers to set
numeric guidelines and standards for percent retention based on
uniformly-weighted summary statistics as opposed to volume weighted
summary statistics.
EPA proposed numeric limitations and standards under the assumption
that, on a long-term average basis, good engineering practice would
allow appropriately designed and well operated solids control equipment
systems to perform at least as well as approximately 95% of the systems
whose data were used to develop the limitations and standards.
Operationally, cuttings retention values are averaged over the course
of drilling an individual well and EPA's candidate BAT limitation or
NSPS is the estimated 95th percentile for the available well averages.
The CWA confers considerable discretion in determining what
constitutes best available technology and best available demonstrated
technology. In exercising this discretion, the Agency has proposed and
promulgated limitations and standards that provide for the variability
observed in application of these technologies. This allowance provides
for variation in the performance of the recommended treatment
technologies and establishes a standard that EPA expects well operated
treatment systems to be capable of achieving at all times.
Given that there is less experience to date with the application of
the cuttings dryer technology than many other candidate BAT and NSPS
technologies generally, the Agency is also considering setting numeric
limitations and standards based on the 99th percentile. This would
provide a larger allowance for treatment variability than is provided
by the proposed limitations and standards based on the 95th percentile.
Detailed descriptions of the statistical methods, summary
statistics, overall averages, and percentiles associated with each
technology can be found in section III.C.(a) of the rulemaking record.
IV. Revised Analyses
A. Revised Compliance Costs Results
1. Large Volume Discharges
Based on the revised engineering models described in section III.A
above, EPA revised its calculations of baseline, compliance option, and
incremental compliance costs. The industry profile and the methodology
for estimating costs that were presented with the proposed rule have
not changed for today's notice. The results of the revised compliance
cost analyses are presented in Table IV.A.1.1 for existing sources and
in Table IV.A.1.2 for new sources.
Table IV.A.1.1: Summary Annual Cost/Savings, Existing Sources (1998$/year)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Costs (savings) in 1998$/year [wells/year]
---------------------------------------------------------------------------------------------------------------------
Technology basis Offshore California [wells/ Cook Inlet, Alaska [wells/
Gulf of Mexico [wells/yr] yr] yr] Total [wells/yr]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline/Current Practice
Technology Costs:
Discharge with 11.4% retention 20,032,850.................. NA a........................ NA a....................... 20,032,850
of SBF on cuttings. [94 wells/yr]............... [94 wells/yr]
Zero Discharge via land 3,494,062................... 2,287,281................... 214,237.................... 5,995,580
disposal or onsite injection [23 wells/yr]............... [12 wells/yr]............... [1 well/yr]................ [36 wells/yr]
(current OBF-drilled wells
only).
Total Baseline Costs per 23,526,912.................. 2,287,281................... 214,237.................... 26,028,430
Area. [117 wells/yr].............. [12 wells/yr]............... [1 well/yr]................ [130 wells/yr]
Technology Option Costs:
Discharge with 2.68% retention 20,257,350.................. 2,463,440................... 211,350.................... 22,932,140
of SBF on cuttings. [117 wells/yr].............. [12 wells/yr]............... [1 well/yr]................ [130 wells/yr]
Discharge with 2.45% retention 20,365,837.................. 2,472,517................... 214,672.................... 23,053,026
of SBF on cuttings. [117 wells/yr].............. [12 wells/yr]............... [1 well/yr]................ [130 wells/yr]
Zero Discharge of SBF-wastes 31,666,153b................. NA a........................ NA a....................... 31,666,153
via land disposal or onsite [94 wells/yr]............... [94 wells/yr]
injection.
Incremental Tech. Option Costs
(Savings):
Discharge with 2.68% retention (3,269,562)................. 176,159..................... (2,887).................... (3,096,290)
of SBF on cuttings. [117 wells/yr].............. [12 wells/yr]............... [1 well/yr]................ [130 wells/yr]
Discharge with 2.45% retention (3,161,075)................. 185,236..................... 435........................ (2,975,404)
of SBF on cuttings. [117 wells/yr].............. [12 wells/yr]............... [1 well/yr]................ [130 wells/yr]
[[Page 21563]]
Zero Discharge of SBF-wastes 11,633,303c................. NA a........................ NA a....................... 11,633,303
via land disposal or onsite [94 wells/yr]............... [94 wells/yr]
injection.
--------------------------------------------------------------------------------------------------------------------------------------------------------
a NA: Not applicable since currently there are no discharges of SBF-cuttings in these waters.
b This technology option cost estimates zero discharge costs associated with the 94 GOM wells that are currently allowed to discharge SBF.
c This incremental technology option cost only covers the 94 GOM wells that are currently allowed to discharge SBF and does not include baseline
compliance costs of zero discharge for the 23 GOM OBF wells (i.e., $3,494,062).
Table IV.A.1.2: Summary Annual Cost/Savings, New Sources (1998$/year)
------------------------------------------------------------------------
Technology basis Gulf of Mexico
------------------------------------------------------------------------
Baseline/Current Practice Technology Costs:
Discharge with 11.4% retention of SBF on cuttings. 2,306,325
Technology Option Costs:
Discharge with 2.68% retention of SBF on cuttings. 1,388,250
Discharge with 2.45% retention of SBF on cuttings. 1,395,913
Zero Discharge of SBF-wastes via land disposal or 4,581,838
onsite injection.................................
Incremental Technology Option Costs (Savings):
Discharge with 2.68% retention of SBF on cuttings. (918,075)
Discharge with 2.45% retention of SBF on cuttings. (910,412)
Zero Discharge of SBF-wastes via land disposal or 2,275,513
onsite injection.................................
------------------------------------------------------------------------
Note: All cost estimates in this table are based on an assumption of 19
new source wells per year.
Details of the revised compliance cost data and analyses are
available in a technical support document in section III.C.(b) of the
rulemaking record.
2. Small Volume Discharges
As stated in section III.A.2 of this notice, EPA learned that SBF
is controlled with zero discharge practices at the drill floor, in the
form of vacuums and sumps to retrieve spilled fluid. Industry estimated
that essentially all of the SBF that spills on the rig floor is
recovered using the controls described above. The amount of SBF spilled
on the rig floor that is not captured by current practices is estimated
at less than 1 gallon SBF per 100 feet drilled.
Industry representatives have stated that industry is split on the
practice of discharging accumulated solids with some discharging
accumulated solids provided permit limitations and standards are met
and others opting to haul this material to shore for disposal (see
section II.B.3). Approximately 75 barrels per well of fine solids and
barite, of which up to 25% is SBF, accumulate in the rig mud pits, sand
traps, and other equipment. Several hundred barrels (approximately 200
to 400 barrels) of water are used to wash out the mud pits. Industry
representatives also indicated to EPA that those oil and gas extraction
operations that discharge wash water and accumulated solids first
recover free SBF.
EPA used the line-item costs developed for the zero discharge
compliance cost analysis to calculate per-well and total costs for
existing and new sources to dispose of accumulated solids via hauling
to land based disposal facilities. Section III.A.2 outlines the
assumptions used to calculate the annual zero discharge costs for small
volume wastes given below in Table IV.A.2.1. Overall, the estimated
per-well costs (1998$) were $1,221 for GOM wells, $2,186 for Offshore
California wells, and $10,638 for Cook Inlet wells.
Table IV.A.2.1: Annual Zero Discharge Costs for Small-Volume SBF Wastes (1998$/year)
----------------------------------------------------------------------------------------------------------------
Technology Basis Gulf of Mexico California Cook Inlet, AK Total
----------------------------------------------------------------------------------------------------------------
Existing Sources:
Baseline and BAT/NSPS Discharge Scenarios a. $142,857 $26,235 $10,638 $179,730
Zero Discharge b............................ 114,774 d NA d NA 114,774
New Sources:
All Scenarios (Baseline, BAT/NSPS Discharge, 23,199 d NA d NA 23,199
and Zero Discharge) c......................
----------------------------------------------------------------------------------------------------------------
a Costs are the same for baseline and two discharge scenarios because each analysis is based on 117 wells.
b Zero discharge costs for existing sources are based on 94 wells.
c Costs are the same for all new-source scenarios because each analysis is based on 19 wells.
d NA: Not Applicable.
B. Revised Pollutant Loadings Results
EPA reviewed additional information regarding drilling fluid
additives provided by the industry representatives in response and
subsequent to the February 1999 proposal, and found no information
prompting changes to the concentrations or list of pollutants presented
at the time of proposal. EPA revised the pollutant loadings analysis
according to the changes in the engineering and statistical models
described in section III.A and III.D of this notice.
[[Page 21564]]
The loadings analysis depends on the estimated volumes of cuttings
and SBF discharged per model well for each discharge scenario. Other
than adjusting the loadings to the revised waste volumes and revised
discharge scenarios, the analysis remains unchanged from the February
1999 analyses. Tables IV.B.1 and IV.B.2 present the revised loadings
for existing and new sources, respectively. EPA assumes that operators
will switch from OBFs in the current baseline model to SBFs under both
SBF controlled discharge options. These tables present the loadings
associated with discharges of SBF and entrained fines [e.g., 5 microns
(10-6 meters)]. EPA also calculated the loadings associated
with SBF solids that can be removed by solids control equipment (e.g.,
>5 microns).
Table IV.B.1: Summary Annual SBF Pollutant Loadings for Existing Sources (lbs/year) a
--------------------------------------------------------------------------------------------------------------------------------------------------------
SBF pollutant loadings (reductions) in pounds/year a [wells/year]
Technology basis ---------------------------------------------------------------------------------------------------------------------
Gulf of Mexico Offshore California Cook Inlet, Alaska Total
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline/Current Practice Tech.
Loadings:
Discharge with 11.4% retention 34,364,661.................. b NA........................ b NA....................... 34,364,661
of SBF on cuttings. [94 wells/yr]............... [94 wells/yr]
Zero Discharge via land 0........................... 0........................... 0.......................... 0
disposal or onsite injection [23 wells/yr]............... [12 wells/yr]............... [1 well/yr]................ [36 wells/yr]
(current OBF-drilled wells
only).
Total Baseline Loadings 34,364,661.................. 0........................... 0.......................... 34,364,661
per Area. [117 wells/yr].............. [12 wells/yr]............... [1 well/yr]................ [130 wells/yr]
Technology Option Loadings:
Discharge with 2.68% retention 7,328,175................... 466,072..................... 26,413..................... 7,820,660
of base fluid on cuttings. [117 wells/yr].............. [12 wells/yr]............... [1 well/yr]................ [130 wells/yr]
Discharge with 2.45% retention 6,464,827................... 411,167..................... 23,302..................... 6,889,295
of base fluid on cuttings. [117 wells/yr].............. [12 wells/yr]............... [1 well/yr]................ [130 wells/yr]
Zero Discharge of SBF-wastes 0........................... b NA........................ b NA....................... 0
via land disposal or onsite [94 wells/yr]............... [94 wells/yr]
injection.
Increm. Tech. Opt. Loadings
(Reductions):
Discharge with 2.68% retention (27,036,486)................ 466,072..................... 26,413..................... (26,544,001)
of base fluid on cuttings. [117 wells/yr].............. [12 wells/yr]............... [1 well/yr]................ [130 wells/yr]
Discharge with 2.45% retention (27,899,834)................ 411,167..................... 23,302..................... (27,465,365)
of base fluid on cuttings. [117 wells/yr].............. [12 wells/yr]............... [1 well/yr]............... [130 wells/yr]
Zero Discharge of SBF-wastes (34,364,661)................ b NA........................ b NA....................... (34,364,661)
via land disposal or onsite [94 wells/yr]............... [94 wells/yr]
injection.
--------------------------------------------------------------------------------------------------------------------------------------------------------
a SBF pollutant loadings only includes loadings associated with discharges of SBF and entrained fines (e.g., 5 microns)
b NA Not Applicable
Table IV.B.2: Summary Annual Pollutant Loadings for New Sources (lbs/
year) a
------------------------------------------------------------------------
Technology basis Gulf of Mexico
------------------------------------------------------------------------
Baseline/Current Practice Technology Loadings:
Discharge with 11.4% retention of SBF on cuttings. 3,949,786
Technology Option Loadings:
Discharge with 2.68% retention of SBF on cuttings. 745,855
Discharge with 2.45% retention of SBF on cuttings. 657,981
Zero Discharge of SBF-wastes via land disposal or 0
onsite injection.................................
Incremental Technology Option Loadings (Reductions):
Discharge with 2.68% retention of SBF on cuttings. (3,203,931)
Discharge with 2.45% retention of SBF on cuttings. (3,291,805)
Zero Discharge of SBF-wastes via land disposal or (3,949,786)
onsite injection.................................
------------------------------------------------------------------------
Note: All loading (reduction) estimates in this table are based on an
assumption of 19 new source wells/yr.
a Only includes loadings associated with discharges of SBF and entrained
fines (e.g., 5 microns)
The zero discharge option also reduces the amount of SBF-solids
[i.e., solids that can be removed by solids control equipment (e.g., >5
microns)] from the current baseline. The estimated annual baseline
discharges of SBF-solids from existing sources is 126,321,650 lbs./
year. The estimated annual loadings (in lbs./year) of SBF-solids for
existing sources are: 152,240,270 (2.68% retention controlled discharge
option); 147,673,062 (2.45% retention controlled discharge option); and
0 (zero discharge option). The estimated annual baseline discharge of
SBF-solids from new sources is 14,519,050 lbs./year. The estimated
annual loadings (in lbs./year) of SBF-solids for new sources are:
14,519,050 (2.68% retention controlled discharge option); 14,083,488
(2.45% retention controlled discharge option); and 0 (zero discharge
option). Complete details of the loadings analysis are available in a
technical support document in the rulemaking record for this notice.
C. Revised Non-Water Quality Environmental Impacts (NWQI) Results
1. Air Emissions and Fuel Usage
EPA revised the analysis of the numeric NWQIs of air emissions and
fuel usage pursuant to the changes in the engineering models described
in section III.A of today's notice. Changes to the numeric NWQI
analysis derive from the revised waste volumes, as well as changes in
the BAT/NSPS discharge scenarios.
In both the first and second BAT/NSPS discharge scenarios,
additional air
[[Page 21565]]
emissions and fuel usage result from the addition of the fines removal
unit. Both scenarios also incorporate the average energy and fuel
requirements of the two types of cuttings dryer that EPA observed in
October 1999 (see section II.B.3). In the second BAT/NSPS discharge
scenario in which the fines waste stream is retained for shipping to
land-based disposal, additional air emissions and fuel usage are
incurred for a portion of the supply boat trip, and for trucks and
other equipment involved in the land disposal zero discharge scenario.
As described in section III.A, EPA learned from industry
representatives that onsite injection is not generally technologically
practicable for deep water drilling projects. Therefore, NWQIs
attributable to hauling and land disposing drilling wastes were
assigned to all deep water wells in the zero discharge analysis. Tables
IV.C.1 and IV.C.2 present the revised air emissions (tons/yr) and fuel
(BOE/yr) usage for existing and new sources, respectively.
Other than the specific changes described above, the methodology
for the numeric NWQI analysis is unchanged since the February 1999
proposal. Details of this analysis are available in a technical support
document located in the rulemaking record for this notice.
Table IV.C.1: Summary Annual Non-Water Quality Environmental Impacts, Existing Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
Non-water quality environmental impacts reductions (increases) [wells/year--wpr]
--------------------------------------------------------------------------------------------------------------------------
Gulf of Mexico Offshore California Cook Inlet, AK Total
Technology basis --------------------------------------------------------------------------------------------------------------------------
Air Air
Air emissions Fuel usage Air emissions Fuel usage emissions Fuel usage emissions Fuel usage
(tons/yr) (BOE/yr) (tons/yr) (BOE/yr) (tons/yr) (BOE/yr) (tons/yr) (BOE/yr)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline/Current Practice
NWQIs:
Discharge with 11.4% 42............ 4,512......... aNA........... aNA.......... aNA.......... aNA.......... 42........... 4,512
retention of base fluid [94 wpy]...... [94 wpy]...... [94 wpy]..... [94 wpy]
on cuttings.
Zero Discharge (current 65............ 4,811......... 47............ 2,940........ 2.5.......... 338.......... 115.......... 8,089
OBF-wells only). [23 wpy]...... [23 wpy]...... [12 wpy]...... [12 wpy]..... [1 wpy]...... [1 wpy]...... [36 wpy]..... [36 wpy]
Total Baseline NWQIs 107........... 9,323......... 47............ 2,940........ 2.5.......... 338.......... 157.......... 12,601
per Area. [117 wpy]..... [117 wpy]..... [12 wpy]...... [12 wpy]..... [1 wpy]...... [1 wpy]...... [130 wpy].... [36 wpy]
Technology Option NWQIs:
Discharge with 2.68% 127........... 10,422........ 7.6........... 673.......... 0.06......... 40........... 135.......... 11,135
retention of SBF on [117 wpy]..... [117 wpy]..... [12 wpy]...... [12 wpy]..... [1 wpy]...... [1 wpy]...... [130 wpy].... [130 wpy]
cuttings.
Discharge with 2.45% 191........... 15,685........ 52............ 853.......... 0.20......... 67........... 243.......... 16,605
retention of SBF on [117 wpy]..... [117 wpy]..... [12 wpy]...... [12 wpy]..... [1 wpy]...... [1 wpy]...... [130 wpy].... [130 wpy]
cuttings.
Zero Discharge of SBF- 561........... 39,702........ aNA........... aNA.......... aNA.......... aNA.......... 561.......... 39,702
wastes via land disposal [94 wpy]...... [94 wpy]...... [94 wpy]
or onsite injection.
Incr. Tech. Opt. NWQI Red.
(Incr.):
Discharge with 2.68% 20............ (1,099)....... 40............ 2,267........ 2.45......... 298.......... 22........... 1,466
retention of SBF on [117 wpy]..... [117 wpy]..... [12 wpy]...... [12 wpy]..... [1 wpy]...... [1 wpy]...... [130 wpy].... [130 wpy]
cuttings.
Discharge with 2.45% (84).......... (6,362)....... (4.8)......... 2,087........ 2.31......... 271.......... (87)......... (4,004)
retention of SBF on [117 wpy]..... [117 wpy]..... [12 wpy]...... [12 wpy]..... [1 wpy]...... [1 wpy]...... [130 wpy].... [130 wpy]
cuttings.
Zero Discharge of SBF- (519)......... (35,191)...... aNA........... aNA.......... aNA.......... aNA.......... (519)........ (35,191)
wastes via land disposal [94 wpy]...... [94 wpy]...... [94 wpy]..... [94 wpy]
or onsite injection.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: 1 ton = 2000 lbs; BOE = barrels of oil equivalent
a NA: Not Applicable
Table IV.C.2: Summary Annual Non-Water Quality Environmental Impacts,
New Sources
------------------------------------------------------------------------
Gulf of Mexico
-------------------------------
Technology basis Air emissions Fuel usage
(tons/yr) (BOE/yr)
------------------------------------------------------------------------
Baseline/Current Practice Technology
NWQIs:
Discharge with 11.4% retention of 4.8 515
SBF on cuttings....................
Technology Option NWQIs:
Discharge with 2.68% retention of 13 1,073
SBF on cuttings....................
Discharge with 2.45% retention of 23 1,923
SBF on cuttings....................
Zero Discharge of SBF-wastes via 68 4,784
land disposal or onsite injection..
Incremental Technology Option NWQIs
Reductions (Increases):
Discharge with 2.68% retention of (8.2) (558)
SBF on cuttings....................
Discharge with 2.45% retention of (18) (1,408)
SBF on cuttings....................
Zero Discharge of SBF-wastes via (63) (4,269)
land disposal or onsite injection..
------------------------------------------------------------------------
Note: All NWQI reductions (increases) in this table are based on an
assumption of 19 new source wells/yr
Note: 1 ton = 2000 lbs; BOE = barrels of oil equivalent
[[Page 21566]]
2. Solid Waste Generation and Management
EPA assumes that based on the relative cheaper cost of OBF
(approximately 5 times less expensive per barrel than SBFs), operators
will use OBFs rather than SBFs if EPA selects the zero discharge option
for all SBF-wastes. Consequently, operators will be land disposing or
injecting OBFs if EPA selects the zero discharge option for all SBF-
wastes.
As stated in the February 1999 proposal, the regulatory options
considered for this rule will not cause generation of additional
solids. However, EPA calculated the amount of waste cuttings that would
be land disposed and injected onsite in each regulatory scenario, and
determined that there would be a considerable reduction in the amount
of mineral-oil or diesel oil-contaminated cuttings land disposed and
injected with the implementation of either of the controlled discharge
options.
Applying the revised waste volumes and discharge scenarios
described above, the accounting of disposed waste is revised as
follows. In the baseline analysis, wells that currently drill using
OBFs generate 27 million (MM) pounds of waste cuttings that are land
disposed, and 6.8 MM pounds that are injected onsite, for a total of 34
MM pounds of waste cuttings disposed. This amount of disposed waste
would be reduced to zero under the BAT/NSPS options allowing discharge
at 2.68% retention, and would be reduced to 6.4 MM pounds under the
BAT/NSPS option allowing discharge at 2.45%. The 6.4 MM pounds disposed
in the second discharge scenario is the fine particle waste retained
for hauling to land based disposal. Under the zero discharge option,
the baseline amount of waste disposed is increased to 152 MM pounds.
3. Safety Issues
The impact of the effluent limitation guidelines (ELG) on safety is
one factor considered in the non-water quality environmental impact
analysis. EPA has identified two safety issues related to drilling
fluids: (1) deleterious vapors generated by organic materials in
drilling fluids; and (2) waste hauling activities that increase the
risk of injury to workers. EPA is requesting comments and data related
to these two safety issues as well as other safety issues related to
drilling fluid selection and waste management.
a. Vapors Generated by Organic Materials in Drilling Fluids. One of
the key concerns in exploration and production projects is the exposure
of wellsite personnel to vapors generated by organic materials in
drilling fluids (Candler et al., 1995). Areas on the drilling location
with the highest exposure potentials are sites near solids control and
open pits. These areas are often enclosed in rooms and ventilated to
prevent unhealthy levels of vapors from accumulating. If the total
volume of organic vapors can be reduced then any potential health
effects will also be reduced regardless of the nature of the vapors.
Generally speaking the aromatic fraction of the vapors is the most
toxic to the mammalian system. The high volatility and absorbability
through the lungs combined with their high lipid solubility serve to
increase their toxicity. OBFs have a high aromatic content and vapors
generated from using these drilling fluids include aromatics (e.g.,
alkybenzenes, naphthalenes, and alkyl-naphthalenes), alkanes (e.g.,
C7-C18 straight chained and branched), and
alkenes. Some minerals oils also generate vapors that contain the same
types of chemical compounds, but generally at lower concentrations, as
those found in the diesel vapors (e.g, aromatics, alkanes, cyclic
alkanes, and alkenes). Because SBF are manufactured from compounds with
specifically defined compositions, the subsequent compound can exclude
toxic aromatics. Consequently, toxic aromatics can be excluded from the
vapors generated by using SBFs.
In general, SBFs (e.g., esters, LAOs, PAOs, IOs) generate much
lower concentrations of vapors than do OBFs (Candler et al., 1995).
Moreover, the vapors generated by these SBFs are less toxic than
traditional OBFs because they do not contain aromatics.
b. Waste Hauling Activities. Industry has commented in previous
effluent guidelines, such as the Coastal Subcategory Oil and Gas
Extraction and Development ELG, that a zero discharge requirement would
increase the risk of injury to workers due to increased waste hauling
activities. These activities include vessel trips to and from the
drilling platform to haul waste, transfer of waste from the platform
onto a service vessel, and transfer in port onto a barge or dock.
EPA has identified and reviewed additional data sources to
determine the likelihood that imposition of a zero discharge limitation
on cuttings contaminated with SBF could increase risk of injury due to
additional waste hauling demands. The sources of safety data are the
U.S. Coast Guard (USCG), the Minerals Management Service (MMS), the
American Petroleum Institute (API), and the Offshore Marine Service
Association (OMSA). The following is a summary of the findings from
this review.
The data indicate that there are reported incidents that are
associated with the collection, hauling, and onshore disposal of wastes
from offshore. However, the data do not distinguish whether any of
these incidents can be attributed to specific waste management
activities.
Most offshore incidents are due to human error or equipment
failure. The rate at which these incidents occur will not be changed
significantly by increased waste management activities. However, if the
number of man hours and/or equipment hours are increased, there will be
more reportable incidents given an unchanged incident rate. These
potential increases may be offset by reduced incident rates through
increased training or equipment maintenance and inspection; but these
changes cannot be predicted. One indication that training and
maintenance can reduce incident rates is a 1998 API report entitled
``1997 Summary of U.S. Occupational Injuries, Illnesses, and Fatalities
in the Petroleum Industry,'' which established that injury incident
rates have been decreasing over the last 14 years. If this decrease
continues, there should be no increase in the number of safety
incidents due to a requirement to haul SBF-contaminated cuttings to
shore for disposal. The details of this analysis are available in a
technical support document in the rulemaking record for today's notice.
4. Monetized Health Benefits
EPA estimated emissions associated with each of the regulatory
options as part of the NWQI analyses. The pollutants considered in the
NWQI analyses are nitrogen oxides (NOX), volatile organic
carbon (VOC), particulate matter (PM), sulfur dioxide (SO2),
and carbon monoxide (CO). Of these pollutants, EPA has monetized the
human health benefits or impacts associated with VOC, PM, and
SO2 emissions using the methodology presented in the
Environmental Assessment of the Final Effluent Limitations Guidelines
and Standards for the Pharmaceutical Manufacturing Industry (EPA-821-B-
98-008). Each of these pollutants have human health impacts and
reducing these emissions can reduce these impacts.
Several VOCs exhibit carcinogenic and systemic effects and VOCs, in
general, are precursors to ground-level ozone, which negatively affects
human health and the environment. PM impacts include aggravation of
[[Page 21567]]
respiratory and cardiovascular disease and altered respiratory tract
defense mechanisms. SO2 impacts include nasal irritation and
breathing difficulties in humans and acid deposition in aquatic and
terrestrial ecosystems.
The unit values (in 1990 dollars) are $489 to $2,212 per megagram
(Mg) of VOC; $10,823 per Mg of PM; and $3,516 to $4,194 per Mg of
SO2. Using the Engineering News Record Construction Cost
Index (see www.enr.com/cost/costcci.asp) these conversion factors are
scaled up using the ratio of 5920:4732 (1998$:1990$). EPA currently
does not have unit values for CO and NOX and is soliciting
information regarding their valuation. Following is a summary of the
monetized benefits for each of the regulatory options for both existing
and new sources.
Table IV.C.3: Summary of Monetized Human Health Benefits or Impacts Associated With VOC, PM, and SO2 Emissions,
Existing Sources (1998$/yr)
----------------------------------------------------------------------------------------------------------------
Criteria air pollutant
---------------------------------------------------------------------------
VOC PM SO2
----------------------------------------------------------------------------------------------------------------
Baseline/Current Practice Air
Emissions, Mg/yr:
Discharge with 11.4% retention 2.15.................... 1.87................... 1.74
of SBF on cuttings.
Zero Discharge (current OBF 9.57.................... 1.93................... 1.68
wells only).
Total Baseline Air 11.72................... 3.80................... 3.42
Emissions, Mg/yr.
Compliance Air Emissions, Mg/yr:
(1) Discharge with 2.68% 6.90.................... 5.98................... 5.57
retention of SBF on cuttings.
(2) Discharge with 2.45% 25.68................... 9.65................... 8.45
retention of SBF on cuttings.
(3) Zero Discharge a............ 113.84.................. 20.96.................. 18.42
Incremental Compliance Emission
Reductions (Increases), Mg/yr:
(1) Discharge with 2.68% 4.82.................... (2.18)................. (2.15)
retention of SBF on cuttings.
(2) Discharge with 2.45% (13.96)................. (5.85)................. (5.03)
retention of SBF on cuttings.
(3) Zero Discharge a............ (11.69)................. (19.09)................ (16.68)
Unit Value of Poll. Reductions, 489 to 2,212............ 10,823................. 3,516 to 4,194
1990$/Mg: b.
Unit Value of Poll. Reductions, 612 to 2,767............ 13, 540................ 4,399 to 5,247
1998$/Mg: c.
Incremental Compliance Benefits
(Costs), 1998$/yr:
(1) Discharge with 2.68% 2,950 to 13,337......... (29,517)............... (9,458) to (11,281)
retention of SBF on cuttings.
(2) Discharge with 2.45% (8,544) to (38,627)..... (79,209)............... (22,127) to (26,392)
retention of SBF on cuttings.
(3) Zero Discharge a............ (68,354) to (309,046)... (258,479).............. 73,375) to (87,520)
----------------------------------------------------------------------------------------------------------------
a Via land disposal or on-site offshore injection
b Conversion factors from Environmental Assessment of the Final Effluent Limitations Guidelines and Standards
for the Pharmaceutical Manufacturing Industry cents (EPA-821-B-98-008).
c Scaled from 1990$ using the Engineering News Record Construction Cost Index.
Table IV.C.4: Summary of Monetized Human Health Benefits or Impacts Associated with VOC, PM, and SO2 Emissions,
New Sources (1998$/yr)
----------------------------------------------------------------------------------------------------------------
Criteria air pollutant
---------------------------------------------------------------------------
VOC PM SO2
----------------------------------------------------------------------------------------------------------------
Baseline/Current Industry Practice
Air Emissions, Mg/yr:
Discharge with 11.4% retention 0.25.................... 0.21................... 0.20
of SBF on cuttings..
Compliance Air Emissions, Mg/yr:
(1) Discharge with 2.68% 0.66.................... 0.57................... 0.53
retention of SBF on cuttings.
(2) Discharge with 2.45% 2.73.................... 0.91................... 0.88
retention of SBF on cuttings.
(3) Zero Discharge a............ 14.62................... 2.67................... 2.32
Incremental Compliance Emission
Reductions (Increases), Mg/yr:
(1) Discharge with 2.68% (0.41).................. (0.36)................. (0.33)
retention of SBF on cuttings.
(2) Discharge with 2.45% (2.48).................. (0.70)................. (0.68)
retention of SBF on cuttings.
(3) Zero Discharge a............ (14.37)................. (2.45)................. (2.13)
Unit Value of Poll. Reductions, 489 to 2,212............ 10,823................. 3,516 to 4,194
1990$/Mg: b.
Unit Value of Poll. Reductions, 612 to 2,767............ 13,540................. 4,399 to 5,247
1998$/Mg: c.
Incremental Compliance Benefits
(Costs), 1998$/yr:
(1) Discharge with 2.68% (251) to (1,134) (4,874)................ (1,452) to (1,731)
retention of SBF on cuttings.
(2) Discharge with 2.45% (1,518) to (6,862) (9,478)................ (2,991) to (3,568)
retention of SBF on cuttings.
(3) Zero Discharge a............ (8,794) to (39,762) (33,173)............... (9,370) to (11,176)
----------------------------------------------------------------------------------------------------------------
\a\ Via land disposal or on-site offshore injection.
[[Page 21568]]
\b\ Conversion factors from Environmental Assessment of the Final Effluent Limitations Guidelines and Standards
for the Pharmaceutical Manufacturing Industry (EPA-821-B-98-008).
\c\ Scaled from 1990$ using the Engineering News Record Construction Cost Index.
D. Revised Cuttings Retention Limitations and Standards
As stated in the February 1999 proposal, EPA is considering setting
limitations and standards for the percent retention of synthetic-based
drilling fluids on cuttings that may be discharged from the cuttings
dryer and fines removal technologies. EPA received cuttings retention
data after the February 1999 proposal (see section II.A.4) and revised
its statistical models (see section III.D).
As demonstrated by oil drilling operations in various geologic
formations within the Gulf of Mexico (see section II.A.4), the average
of the individual well averages for percent SBF retention on cuttings
from the cuttings dryer is 2.45, the estimated 95th percentile is 3.11,
and the estimated 99th percentile is 3.38. The observed individual well
averaged SBF cuttings retention values are all less than the 95th
percentile. For fines removal equipment, the average of the individual
well averages for percent SBF retention on cuttings is 10.0, the
estimated 95th percentile is 13.1, and the estimated 99th percentile is
14.4. Only one of the observed individual well SBF cuttings retention
values for fines removal equipment exceeds the 95th percentile and none
exceed the 99th percentile.
Based on these summary statistics, EPA has revised the proposed
limitations and standards for percent retention of drilling fluids on
cuttings. Assuming that: (a) 97% of the volume of cuttings discharged
come from the cuttings dryer and 3% from fines removal; and (b) the
limit will be based on a 95th percentile; the new discharge limitation
of base fluid retained on cuttings is 3.41% [i.e., (0.97)(3.11%) +
(0.03)(13.1%) = 3.41%]. Assuming that: (a) 97% of the volume of
cuttings discharged come from the cuttings dryer and 3% from fines
removal; and (b) the limit will be based on a 99th percentile; the new
discharge limitation of base fluid retained on cuttings is 3.71% [i.e.,
(0.97)(3.38%) + (0.03)(14.4%) = 3.71%].
EPA is also considering basing percent retention limitations and
standards on the cuttings dryer alone, in conjunction with zero
discharge for all other cuttings. In that case, the discharge
limitation of base fluid retained on cuttings would be 3.11% when using
the 95th percentile or 3.38% when established using the 99th
percentile.
If EPA selects numeric maximum well averaged cuttings retention
discharge limitations and standards as the only method for controlling
SBF discharges associated with cuttings in the final rule, then all
operators would be expected to either: (1) meet the numeric maximum
well averaged cuttings retention limitations and standards; or (2)
dispose of their waste through on-site formation injection or ship
their cuttings to shore for land disposal. In addition, EPA may elect
in the final rule to allow operators the flexibility of choosing either
numeric limitations and standards or BMPs to control SBF discharges
associated with cuttings (see section V). A detailed description of the
statistical analyses used to develop the proposed limitations and
standards for percent retention of drilling fluids on cuttings is given
in section III.C.(a) of the rulemaking record.
E. Revised Environmental Assessment Results
The complete results of the revised EA analyses are given in
section III.F.(b) of the rulemaking record.
1. Water Column Water Quality Analyses
In the February 1999 proposal EA analyses, there were no
exceedances of water quality criteria in the water column. Based on the
revised EA analyses using updated dilution values and Federal water
quality criteria, there are still no water quality criteria exceedances
in the water column for any of the regulatory options being considered.
2. Pore Water Quality Analyses
The revised EA analyses estimate that baseline-model (or BPT) pore
water pollutant concentrations at 100 m from the discharge exceed
water-quality criteria for: (1) three pollutants (Cr, Pb, Ni) for the
deep water exploratory well; (2) one pollutant (Cr) for the shallow
exploratory well; and one pollutant (Cr) for the deepwater development
well. Barite is used as a weighting agent in the drilling fluid and is
also the primary source of heavy metals (e.g., Cr, Pb, Ni) in SBF.
Therefore, the baseline-model pore water exceedances are not due to the
synthetic material in the SBF but rather the SBF weighting agents.
The revised EA analyses estimate that both BAT/NSPS-model
controlled discharge options result in no pore water pollutant
concentrations that exceed water-quality criterion.
3. Sediment Guidelines Analyses
In the February 1999 proposal, the BAT/NSPS-model controlled
discharge option resulted in sediment guidelines exceedances for the
deep water and shallow water exploratory wells. EPA proposed sediment
guidelines can be found in section I.D.(a).13 of the rulemaking record.
The revised EA sediment guidelines analyses, based on updated water
quality criteria, loadings, and dilution data, result in exceedances
under the baseline model (or BPT) scenario only. There are no sediment
guidelines exceedances for any of the BAT/NSPS-models.
V. Best Management Practices (BMPs) Alternatives to Numeric
Limitations and Standards
A. General
EPA is considering three options for the final rule for the BAT
limitation and NSPS controlling SBF retained on discharged cuttings:
(1) a single numeric discharge limitation with an accompanying
compliance test method; (2) allowing operators to choose either a
single numeric discharge limitation with an accompanying compliance
test method, or as an alternative, a set of BMPs that employs limited
cuttings monitoring; or (3) allowing operators to choose either a
single numeric discharge limitation with an accompanying compliance
test method or an alternative set of BMPs that employ no cuttings
monitoring. Additionally, EPA is considering two options in the final
rule for BAT limitation and NSPS for controlling SBFs not associated
with SBF drill cuttings: (1) zero discharge; or (2) allowing operators
to choose either zero discharge or an alternative set of BMPs with an
accompanying compliance method.
EPA has initial data on the effectiveness of BMPs for controlling
SBF-discharges (Farmer, 2000; Hanni et al, 1998). The initial data on
BMP effectiveness was generated from over 12 deepwater projects in the
North Sea and 11 deepwater projects in the GOM. Data from Farmer (2000)
was received by EPA just before publication of this notice and was
unable to be fully analyzed. This data set represented North Sea and
GOM wells that did not employ a cuttings dryer, however, certain
drilling projects in the data set did use an extra technician (``mud
cop'') to assist in improving the efficiency of the existing solids
control equipment through use of BMPs.
[[Page 21569]]
EPA is requesting additional data on the use of BMPs to reduce or
prevent SBF-discharges. In particular, EPA would like to see BMP
documentation associated with cuttings retention spreadsheets similar
to those submitted to support the development of the numeric guidelines
and standards for the retention of SBF on cuttings. EPA will be using
these data sets to determine the effectiveness of BMPs and their use as
alternatives to numeric limitations and standards. EPA may select any
of these BMP alternative options or any combination of these BMP
alternative options in the final rule.
Sections 304(e), 308(a), 402(a), and 501(a) of the Clean Water Act
authorize the Administrator to prescribe BMPs as part of effluent
limitations guidelines and standards or as part of a permit. EPA's BMP
regulations are found at 40 CFR 122.44(k). Section 304(e) of the CWA
authorizes EPA to include BMPs in effluent limitation guidelines for
certain toxic or hazardous pollutants for the purpose of controlling
``plant site runoff, spillage or leaks, sludge or waste disposal, and
drainage from raw material storage.'' Section 402(a)(1) and NPDES
regulations [40 CFR 122.44(k)] also provide for best management
practices to control or abate the discharge of pollutants when numeric
limitations and standards are infeasible. In addition, section
402(a)(2), read in concert with section 501(a), authorizes EPA to
prescribe as wide a range of permit conditions as the Administrator
deems appropriate in order to ensure compliance with applicable
effluent limitations and standards and such other requirements as the
Administrator deems appropriate.
SBFs adhered to discharged cuttings may contain barite (used as a
weighting agent in the drilling fluid system), and can also be
contaminated with formation crude oil. Barite is a mineral principally
composed of barium sulfate, however, barite ore is generally known to
have trace contaminants of several heavy metals such as mercury,
cadmium, arsenic, chromium, copper, lead, nickel, and zinc. Formation
oil is an ``indicator'' pollutant for the many toxic and hazardous
pollutant components present in the formation (crude) oil, such as
aromatic and polynuclear aromatic hydrocarbons. These formation oil
pollutants include benzene, toluene, ethylbenzene, naphthalene,
phenanthrene, and phenol. For a complete listing of pollutants
associated with SBF readers should turn to Table VII-1 in the EPA
February 1999 proposal SBF Development Document (EPA-821-B-98-021).
Many of these SBF pollutants are designated as hazardous pollutants
under CWA section 307(a)(1), see 40 CFR. 410.15, and oil is a hazardous
substance under section 311 of the CWA.
It should also be noted that many of these same pollutants can also
be found in SBF discharges not associated with cuttings (e.g.,
incidental spills, accumulated solids, deck drainage). Also, the
drilling fluid (SBF based) can contain barite and trace contaminants of
several heavy metals. Incidental spills of SBF can release these toxic
and hazardous pollutants into the environment. In addition,
approximately 75 barrels per well of solids, of which up to 25% is SBF,
accumulate in the rig mud pits, sand traps, and other equipment. These
accumulated solids may be discharged during equipment cleaning
operations.
SBF discharges such as spills and leaks and accumulated solids may
also be co-mingled with deck drainage which may also contain other
toxic and hazardous pollutants. Deck drainage includes all water
resulting from spills, platform washings, deck washings, tank cleaning
operations and run-off from curbs, gutters, and drains including drip
pans and work areas. Lists of pollutants and pollutant concentrations,
including toxic and hazardous pollutants, in untreated deck drainage
are contained in Tables X-17, X-18, and X-19 of the Final Offshore
Development Document (EPA-821-R-93-003).
Therefore, the BMP alternatives to numeric limitations and
standards in this notice are directed, among other things, at
preventing or otherwise controlling leaks, spills, and discharges of
toxic and hazardous pollutants in SBF cuttings and non-cuttings wastes.
B. BMP Alternatives for SBF Discharges Associated with Cuttings
As previously stated, EPA is considering three options for the
final rule for the BAT limitation and NSPS controlling SBF retained on
discharged cuttings: (1) A single numeric discharge limitation with an
accompanying compliance test method; (2) allowing operators to choose
either a single numeric discharge limitation with an accompanying
compliance test method, or as an alternative, a set of BMPs that
employs limited cuttings monitoring; or (3) allowing operators to
choose either a single numeric discharge limitation with an
accompanying compliance test method or an alternative set of BMPs that
employ no cuttings monitoring. The BMP alternatives were developed with
input from EPA Regional permit writers and industry. Under the third
alternative cuttings discharge, BMPs option (i.e., cuttings not
monitored), EPA is also considering whether to require as a BMP the use
of a cuttings dryer discussed above as representative of BAT/NSPS or to
make the use of a cuttings dryer optional.
Some industry representatives have expressed an interest in using
BMPs that are not demonstrated through limited cuttings monitoring as
equivalent to a numeric cuttings retention limit to control discharges
of SBF associated with cuttings. Two issues were identified by the
industry representatives as a basis for their support of using BMPs as
an alternative discharge limitation: (1) Low gravity solids (or
``fines'') build-up in an active mud system; and (2) engineering
limitations in the installation of cuttings dryers and supporting
equipment on certain rigs. If operators are correct in their assertion
that setting a numeric cuttings retention limit is infeasible, EPA may
use BMPs to control SBF-wastes.
As discussed in the Development Document for the February 1999
Proposal (EPA-821-B-98-021), solids control equipment generally
increases the mechanical degradation of drill solids (i.e., larger
particles are broken into smaller particles). An undesirable increase
in drilling fluid weight and viscosity can occur when drill solids
degrade into fines that cannot be removed by solids control equipment
[i.e., generally classified as 5 microns (10-\6\ meters) in length].
An unacceptable high fines content (i.e., generally > 5% of total
drilling fluid weight) may consequently lead to drilling problems
(e.g., undesirable rheological properties, stuck pipe). Therefore, it
is possible that the increased recovery of SBF from cuttings for re-use
in the active mud system, often achieved through use of the cuttings
dryer in solids control systems, may lead to a build-up in fines for
certain formation characteristics (e.g., high reactivity of formation
cuttings, limited loss of drilling fluid into the formation).
In order to meet EPA's proposed numeric cuttings retention value
where there are unfavorable formation characteristics, operators may be
limited to: (1) Diluting the fines in the active mud system through the
addition of ``fresh'' SBF; and/or (2) capturing a portion of the fines
in a container and sending the fines to shore for disposal. One SBF
manufacturer stated in a verbal conversation with EPA that over the
course of the past year (1999), a Canadian operator generated 12,000
barrels of SBF which had a fines content
[[Page 21570]]
that rendered it unusable and untreatable for future drilling
applications.
Currently, however, EPA does not have documentation that the build-
up of fines in SBF drilling is a widespread problem in the United
States or one that cannot be handled by operators in the United States.
The absence of documented fines build-up problems in the GOM may be due
to a sufficient loss of SBF drilling fluid with fines down-hole. This
loss of fluid into the formation would require the addition of fresh
SBF drilling fluid and minimize the build-up of fines. In addition,
drilling rigs are now being designed and constructed to incorporate
cuttings dryer and fines removal equipment into the solids control
system. EPA is requesting data and comments on the expected frequency
and conditions where operators are not able to meet EPA's new proposed
SBF numeric cuttings retention numbers (see section IV.C.5) based on
fines build-up in the active mud system.
Some industry representatives have also suggested that some rigs
are incapable of installing the equipment needed to meet EPA's proposed
numeric cuttings retention limit (e.g., cuttings dryers, fines removal
equipment). EPA staff visited two offshore GOM rigs where cuttings
dryer and fines removal equipment was and was not able to be installed
successfully into the existing solids control equipment system. The
cuttings dryer that was able to be installed into the existing solids
control system was smaller than the other cuttings dryer system on the
other visited rig. Moreover, the successful installation also relied on
an auger transport system for moving cuttings from the existing solids
control system to the new cuttings dryer and fines removal equipment.
The key cuttings dryer and fines removal equipment installation
limitations appear to be whether rigs can install cuttings dryers and
fines removal equipment near the existing solids control units and
whether an auger cuttings transport system can be used to move cuttings
from the existing solids control units to the new equipment. EPA's site
visit and statements by industry representatives give differing
viewpoints on how many rigs cannot incorporate new equipment to meet
EPA's proposed cuttings retention number. Therefore, EPA requests
further information and data to identify the name and number of rigs
that cannot incorporate new equipment to meet EPA's cuttings retention
number.
C. BMP Alternatives for SBF Discharges Not Associated with Cuttings
As previously stated, EPA is considering two options in the final
rule for BAT limitation and NSPS for controlling SBFs not associated
with SBF drill cuttings: (1) zero discharge; or (2) allowing operators
to choose either zero discharge or an alternative set of BMPs with an
accompanying compliance method. The follow sections describe several
types of SBF discharges not associated with cuttings that can be
controlled through either zero discharge or a set of BMPs. At this
time, EPA's preferred option for these SBF non-cuttings wastes is to
give operators the choice of selecting either zero discharge or using a
set of BMPs to control these discharges (Option 2 identified above).
This approach would give operators the flexibility of selecting a
single numeric effluent limitation or a set of BMPs designed for their
respective facility.
1. Accumulated Solids
Accumulated solids is one example of a non-cuttings SBF discharge.
Industry representatives have stated that industry is split on the
practice of discharging accumulated solids with some discharging
accumulated solids provided permit limitations and standards are met
and others opting to haul this material to shore for disposal (see
section II.B.3). Approximately 75 barrels per well of fine solids and
barite, of which up to 25% is SBF, accumulate in the rig mud pits, sand
traps, and other equipment. Several hundred barrels (approximately 200
to 400 barrels) of water are used to wash out the mud pits. Industry
representatives also indicated that those oil and gas extraction
operations that discharge wash water and accumulated solids first
recover free SBF.
Industry has submitted to EPA Region 6 and EPA Headquarters a list
of BMPs that can minimize these discharges. Accordingly, Industry may
wish to select BMPs as the method for controlling these discharges
instead of zero discharge.
2. SBF Spills During Drilling Operations
Industry also noted that BMPs are already in place on most rigs to
prevent spills during connections and disconnections of the drill
string. Typical waste minimizing techniques include slugging the pipe
(a small volume of heavy mud is pumped into the drill pipe to create a
hydrostatic differential inside the drill pipe) with heavy mud. Rubber
wipers may also be used on the inside and outside of the drill pipe to
remove any residual mud before racking the pipe in the derrick (i.e.,
storing the pipe on the rig). In some cases, the mud is captured with
mud buckets and returned to the active mud system. Any spills on the
rig floor can also be squeegeed back through the rotary into the mud
system. A mud vacuum is also sometimes used. Pipe racks and the rig
floor may also be designed with drip pans underneath to capture any
remaining spillage. Captured fluid may go to the rig's oil/water sump
for treatment and possible recovery. Industry estimated that
essentially all of the SBF that spills on the rig floor is recovered
using the controls described above. The amount of SBF spilled on the
rig floor that is not captured by current practices is estimated by
industry to be less than 1 gallon SBF per 100 feet drilled.
Industry may wish to select BMPs as the method for controlling
these discharges instead of zero discharge.
D. Implementation of BMP Alternative (the BMP Plan)
BMPs are inherently pollution prevention practices. BMPs may
include the universe of pollution prevention encompassing production
modifications, operational changes, material substitution, materials
and water conservation, and other such measures. BMPs include methods
to prevent toxic and hazardous pollutants from reaching receiving
waters. Because BMPs are most effective when organized into a
comprehensive facility BMP Plan, EPA solicits comments on a BMP Plan
requirement as a component of BMPs as an alternative to a numeric
limitation or standard.
A BMP Plan would not be required if operators did not use BMPs to
control SBF discharges. Moreover, EPA is proposing that operators be
allowed to choose whether one or both of the two SBF wastestream (i.e.,
SBF discharges associated with cuttings, SBF discharges not associated
with cuttings) be managed through the BMP alternatives.
Accordingly, EPA is also proposing that operators only be required
to develop and implement a BMP Plan for those SBF wastestreams it
elects to manage through the BMP alternatives. Moreover, EPA is
proposing that operators only be required to develop one BMP Plan if it
elects to manage both SBF wastestreams (e.g., discharges associated
with cuttings and SBF discharges not associated with cuttings) through
use of the BMP alternatives. As there are common elements in BMP Plans
that cover both SBF wastestreams, EPA has grouped common elements
together and identified specific elements for specific SBF wastestreams
[[Page 21571]]
in separate sections. Table V.D.1 is a guide on what BMP Plan elements
are required for the different BMP alternatives.
The SBF BMP common elements were compiled from several Regional
permits, an EPA guidance document [i.e., Guidance Document for
Developing Best Management Practices (BMP)'' (EPA 833-B-93-004, U.S.
EPA, 1993)], and draft industry BMPs. EPA feels that these common
elements represent the appropriate mix of broad directions needed to
complete a BMP Plan along with specific tasks common to all drilling
operations.
Table V.D.1: BMP Plan Elements Required for the Different BMP Alternatives to SBF Numeric Effluent Limitations
Guidelines and Standards
----------------------------------------------------------------------------------------------------------------
SBF wastestreams operator elects to manage with BMP
alternatives
----------------------------------------------------------- BMP plan elements e
BMP plan alternatives a SBF discharges SBF discharges (listed by section of
SBF discharges not associated with associated with this notice)
associated with cuttings (no cuttings
cuttings b monitoring) c (monitoring) d
----------------------------------------------------------------------------------------------------------------
1............................. X .................. ................. Sec. V.D.1 to 5,6.
2............................. X X ................. Sec. V.D.1 to 5,6,7.
3............................. X .................. X Sec. V.D.1 to 5,6,8.
4............................. .................. X ................. Sec. V.D.1 to 5,7.
5............................. .................. .................. X Sec. V.D.1 to 5,8.
----------------------------------------------------------------------------------------------------------------
a Operators that elect to meet numeric limitations and standards are not required to develop BMPs or a BMP Plan.
b This includes incidental SBF spills, accumulated solids, and deck drainage (see section V.C).
c This includes SBF discharges associated with cuttings with no equivalency determination through monitoring
(see section V.B).
d This includes SBF discharges associated with cuttings with an equivalency determination through monitoring
(see section V.B).
e Operators are only required to develop one BMP Plan if the operator elects to manage both SBF wastestreams
(e.g., discharges associated with cuttings and SBF discharges not associated with cuttings) through use of the
BMP alternatives.
1. SBF BMP Plan Purpose and Objectives
The BMP Plan must be designed to prevent or minimize the generation
and the potential for the discharge of SBF from the facility to the
waters of the United States through normal operations and ancillary
activities. The Permittee must establish specific objectives for the
control of SBF by conducting the following evaluations:
a. The Permittee should identify which SBF wastestreams (i.e.,
cuttings related or non-cuttings related) are to be controlled through
use of the BMP alternatives and which SBF wastestreams are to be
controlled through use of numeric effluent limitation guidelines and
standards.
b. Each facility component or system controlled through use of BMP
alternatives must be examined for its SBF-waste minimization
opportunities and its potential for causing a discharge of SBF to
waters of the United States due to equipment failure, improper
operation, natural phenomena (e.g., rain, snowfall).
c. For each SBF wastestream controlled through BMP alternatives
where experience indicates a reasonable potential for equipment failure
(e.g., a tank overflow or leakage), natural condition (e.g.,
precipitation), or other circumstances to result in SBF reaching
surface waters, the BMP Plan should include a prediction of the
direction, rate of flow and total quantity of SBF which could be
discharged from the facility as a result of each condition or
circumstance.
2. Requirements
The BMP Plan must be consistent with the objectives in section
V.D.1. The BMP Plan may reflect requirements within spill response
plans required by the Minerals Management Service (see 30 CFR 254) or
other Federal or State requirements and incorporate any part of such
plans into the BMP Plan by reference.
The Permittee must certify that its BMP Plan is complete, on-site,
and available upon request to EPA or the NPDES Permit controlling
authority. This certification should identify the NPDES permit number
and be signed by an authorized representative of the Permittee. For new
exploratory operations, the certification should be submitted no later
than the written notice of intent to commence discharge. For existing
dischargers, the certification should be submitted within one year of
permit issuance. The BMP Plan must:
a. Be documented in narrative form, and must include any necessary
plot plans, drawings or maps, and must be developed in accordance with
good engineering practices. At a minimum, the BMP Plan must contain the
planning, development and implementation, and evaluation/reevaluation
components. Examples of these components are contained in ``Guidance
Document for Developing Best Management Practices (BMP)'' (EPA 833-B-
93-004, U.S. EPA, 1993).
b. Include the following provisions concerning BMP Plan review:
(i) Be reviewed by plant engineering staff and the plant manager as
warranted by changes in the operation or at the facility which are
covered by the BMP.
(ii) Be reviewed and endorsed by the individuals responsible for
development and implementation of the BMP Plan. Such review and
endorsement may be performed by the establishment of a program of
documented initial and annual refresher training of drilling equipment
operators, maintenance personnel, and other technical and supervisory
personnel who have responsibility for operating, maintaining, or
supervising the operation and maintenance of drilling equipment.
(iii) Include a statement that the above reviews have been
completed and that the BMP Plan fulfills the requirements set forth in
this section of the notice. The statement must be certified by the
dated signatures of the individuals responsible for development and
implementation of the BMP Plan.
c. Establish specific best management practices to meet the
objectives identified in section V.D.1, addressing each component or
system capable of generating or causing a release of significant
amounts of SBF, and identifying specific preventative or remedial
measures to be implemented.
3. Documentation
The Permittee must maintain a copy of the BMP Plan and related
documentation (e.g., training certifications, summary of the monitoring
results, records of SBF-equipment spills, repairs, and maintenance) at
the facility and must make the BMP Plan and related
[[Page 21572]]
documentation available to EPA or the NPDES Permit controlling
authority upon request. Submission of the BMP Plan and related
documentation shall be at the frequency established by the NPDES permit
control authority (i.e., Permit monitoring reports), but in no case
less than once per five years.
4. BMP Plan Modification
For those SBF wastestreams controlled through BMP alternatives, the
Permittee must amend the BMP Plan whenever there is a change in the
facility or in the operation of the facility which materially increases
the generation of those SBF-wastes or their release or potential
release to the receiving waters. At a minimum the BMP Plan must be
reviewed once every five years and amended within three months if
warranted. Any such changes to the BMP Plan must be consistent with the
objectives and specific requirements listed above. All changes in the
BMP Plan must be reviewed by the plant engineering staff and plant
manager.
5. Modification for Ineffectiveness
At any time, if the BMP Plan proves to be ineffective in achieving
the general objective of preventing and minimizing the generation of
SBF-wastes and their release and potential release to the receiving
waters and/or the specific requirements above, the permit and/or the
BMP Plan must be subject to modification to incorporate revised BMP
requirements.
6. Specific Pollution Prevention Activities for SBF Discharges Not
Associated With Cuttings
An approved BMP Plan may include the following examples of specific
pollution prevention activities for controlling SBF discharges not
associated with cuttings.
a. Establishing programs for identifying, documenting, and
repairing leaking SBF equipment, tracking SBF equipment repairs, and
training personnel to report and evaluate SBF spills, as detailed in
section V.E.2.c and V.E.2.d below.
b. Establishing programs for identifying, documenting, and
repairing malfunctioning SBF equipment, tracking SBF equipment repairs,
and training personnel to report and evaluate malfunctioning SBF
equipment.
c. Recovering and returning to the process or an appropriate
storage container to the maximum extent practicable spilled or leaked
drilling fluids to prevent their discharge.
d. Immediately recovering spills of drilling fluid on the drill
floor using a vacuum, grated trough, or comparable system.
e. Providing adequate containment for SBF spills on the drill deck
to minimize potential spills.
f. Establishing mud pit and equipment cleaning methods in such a
way as to minimize the potential for drilling fluids discharges,
including but not limited to the following:
(i) Ensuring proper operation and efficiency of mud pit agitation
equipment.
(ii) Using mud gun lines during mixing to provide agitation in dead
spaces to minimize solids accumulation.
(iii) Pumping drilling fluids off for use, recycle, or disposal
before using wash water to dislodge solids.
(iv) Limiting the volume of wash water used to the minimum needed
to dislodge and slurry solids for overboard discharge.
(v) Using water-minimizing techniques (e.g., steam or compressed
air) where possible to clean the sides of the mud pit.
g. The Permittee must also include the number and dates of non-
cuttings SBF-discharges managed by BMPs in their NPDES permit reports.
The description of these discharges must also include estimated volume
of SBF discharged and any corrective actions taken to respond to such
non-cuttings SBF-discharges.
7. Specific Pollution Prevention Activities for SBF Discharges
Associated With Cuttings (No-Verification Cuttings Monitoring)
The following specific pollution prevention activities are required
in a BMP Plan when operators elect to control SBF discharges associated
with cuttings by a set of BMPs where no equivalency determination is
made through limited cuttings monitoring.
a. Establishing programs for identifying, documenting, and
repairing malfunctioning SBF equipment, tracking SBF equipment repairs,
and training personnel to report and evaluate malfunctioning SBF
equipment.
b. Establishing operating and maintenance procedures for each
component in the solids control system in a manner consistent with the
manufacturer's design criteria for flow, fluid type, density, and
rheological properties, which may include, but are not limited to, the
following:
(i) Maintaining shale shakers such that units have adequate
capacity for circulating the active drilling fluid volume, have screens
of such mesh size that no more than 75% of screen area is wet, and
maintain the manufacturer's design screen tension, maximum ``G'' force,
maximum positive screen deck angle, and maximum vibrator assembly angle
to screen deck;
(ii) Maintaining centrifuges such that units have sufficient
capacity for active drilling fluid volume (note: for most situations
where 8.5" or larger hole sizes are drilled, multiple units may be
required), have bowl revolutions per minute (RPM) adjusted as high as
practical to maximize ``G'' force, have bowl/conveyor RPM differential
minimized to subject cuttings to ``G'' Force for the maximum time
period before leaving the unit, have feed tube adjusted to introduce
cuttings to the maximum bowl diameter as they enter the unit, and have
processing rates closely monitored to maximize cuttings discharge with
minimum SBF retention.
c. Using gel pills or other applicable measures in order to
minimize contamination of drilling fluids when changing from water-
based to non-aqueous based drilling fluids and vice versa.
d. Sending interface muds through the mud recovery system prior to
discharge or disposal.
8. Specific Pollution Prevention Activities for SBF Discharges
Associated With Cuttings (Verification Cuttings Monitoring)
The following specific pollution prevention activities are required
in a BMP Plan when operators elect to control SBF discharges associated
with cuttings by a set of BMPs that are demonstrated, through limited
cuttings monitoring, to meet the same level of control as the BAT/NSPS
cuttings retention limit.
a. All the specific pollution prevention activities in section
V.D.7
b. A daily retort analysis must be performed (in accordance with
Appendix 7 to Subpart A of Part 435) during the first 0.33 X days where
X is the anticipated total time (in days) to drill that particular
well. The retorts analyses will be documented in the well retort log.
(i) When the arithmetic average of the cuttings retort analyses is
less than the numeric cuttings retention limitation and standard,
monitoring of cuttings may cease for that individual well.
(ii) When the arithmetic average of the cuttings retort analyses is
greater than the numeric cuttings retention limitation and standard,
monitoring will continue for the second 0.33X days where X is the
anticipated total time (in days) to drill that particular well. If
after the second 0.33X, the arithmetic average of the cuttings retort
analyses is still greater than numeric cuttings retention
[[Page 21573]]
limitation and standard then monitoring will continue for the remainder
of the well operation. Moreover, this incident will be reported within
one week to EPA or the NPDES Permit controlling authority for review
and recommendations.
c. The Permittee must also include the cuttings monitoring data and
dates of monitored and non-monitored SBF-cuttings discharges managed by
BMPs in their NPDES permit reports.
E. Paperwork Reduction Act Requirements Related to BMPs Alternatives
The information collection requirements related to the BMP
alternatives in this notice have been submitted for approval to the
Office of Management and Budget (OMB) under the Paperwork Reduction
Act, 44 U.S.C. 3501 et seq. An Information Collection Request (ICR)
document has been prepared by EPA (ICR No. 1953.01) and a copy may be
obtained from Sandy Farmer by mail at Collection Strategies Division,
U.S. Environmental Protection Agency (2822), 1200 Pennsylvania Ave.,
NW, Washington, DC 20460; by e-mail at [email protected], or by
calling (202) 260-2740. A copy may be downloaded from the Internet at
http://www.epa.gov/icr.
The BMP alternatives identified in this notice include information
collection requirements that are intended to control the discharges of
SBF in place of numeric effluent limitations and standards. These
information collection requirements include, for example: (1) Training
personnel; (2) analyzing spills that occur; (3) identifying equipment
items that might need to be maintained, upgraded, or repaired; (4)
identifying procedures for waste minimization; (4) performing
monitoring (including the operation of monitoring systems) to establish
equivalence with a numeric cuttings retention limitation and to detect
leaks, spills, and intentional diversion; and (5) generally to
periodically evaluate the effectiveness of the BMP alternatives.
The BMP alternatives also require operators to develop and, when
appropriate, amend plans specifying how operators will implement the
specified BMP alternatives, and to certify to the permitting authority
that they have done so in accordance with good engineering practices
and the requirements of the regulation. The purpose of those provisions
is, respectively, to facilitate the implementation of BMP alternatives
on a site-specific basis and to help the regulating authorities to
ensure compliance without requiring the submission of actual BMP Plans.
Finally, the recordkeeping provisions are intended to facilitate
training, to signal the need for different or more vigorously
implemented BMP alternatives, and to facilitate compliance assessment.
EPA has structured the BMP alternatives to provide maximum
flexibility to the regulated community and to minimize administrative
burdens on National Pollutant Discharge Elimination System (NPDES)
permit authorities that regulate oil and gas extraction facilities.
Although EPA does not anticipate that operators will be required to
submit any confidential business information or trade secrets as part
of this ICR, all data claimed as confidential business information will
be handled by EPA pursuant to 40 CFR Part 2.
For the five SBF BMP alternatives (see Table V.D.1), the public
reporting burdens range from an estimated 515 hours per respondent per
year [i.e., (12,500 initial hours/3 years + 21,604 annual hours/year)/
50 SBF well operators] to 1,363 hours per respondent per year [i.e.,
(17,500 initial hours/3 years + 62,334 annual hours/year)/50 SBF well
operators]. EPA also estimated the annual burden for EPA Regions, the
NPDES permit controlling authorities, to review BMPs and ensure
compliance. EPA estimates that essentially all of the SBF discharges
will occur in Federal offshore waters or in Cook Inlet, Alaska, where
EPA Region X retains NPDES permit controlling authority. The EPA
Regional burden for reviewing BMP Plans is estimated at 5.7 hours per
year [i.e., (8 initial hours/3 years + 3 annual hours/year)/50 SBF well
operators].
For new exploratory operations, the certification of BMP Plan
completion should be submitted to the permit control authority no later
than the written notice of intent to commence discharge. For existing
dischargers, the certification should be submitted within one year of
permit issuance. In addition, a copy of the completed BMP Plan may be
requested by the NPDES permit control authority at any time. Submission
of records to the permit control authority demonstrating periodic
review of the BMP Plan are due at a minimum once every five years.
Monitoring reports demonstrating compliance with the BMP Plan are due
to the permit control authority at the frequency set by the permit
control authority (e.g., monthly or annually) and may be requested by
the permit control authority on demand. Re-fresher training
certifications demonstrating compliance with the BMP Plan are due to
the permit control authority at the frequency set by the permit control
authority (e.g., semi-annually) and may be requested by the permit
control authority on demand.
For the five SBF BMP alternatives (see Table V.D.1), the public
reporting costs range from approximately $18,600 per respondent per
year [i.e., ($921,875 initial costs/3 years + $623,625 annual costs/
year)/50 SBF well operators] to $38,000 hours per respondent per year
[i.e., ($1,290,625 initial costs/3 years + $1,465,100 annual costs/
year)/50 SBF well operators]. The EPA Regional costs for reviewing BMP
Plans is estimated at approximately $180 per year [i.e., ($12,800
initial costs/3 years + $4,800 annual costs/year) / 50 SBF well
operators].
[[Page 21574]]
Burden means the total time, effort, or financial resources
expended by persons to generate, maintain, retain, or disclose or
provide information to or for a Federal agency. This includes time
needed to: review instructions; develop, acquire, install, and utilize
technology and systems for the purposes of collecting, validating, and
verifying information, processing and maintaining information and
disclosing and providing information; adjust the existing ways to
comply with previously applicable instructions and requirements; train
personnel to be able to respond to the collection of information;
search data sources; complete and review the collection of information;
and transmit or otherwise disclose the information.
An agency may not conduct or sponsor, and a person is not required
to respond to, a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for EPA's
regulations are listed in 40 CFR Part 9 and 48 CFR Chapter 15.
Comments are requested on the Agency's need for this information,
the accuracy of the provided burden estimates, and any suggested
methods for minimizing respondent burden, including through the use of
automated collection techniques. Send comments on the ICR to the
Director, Collection Strategies Division; U.S. Environmental Protection
Agency (2822); 1200 Pennsylvania Ave., NW, Washington, DC 20460; and to
the Office of Information and Regulatory Affairs, Office of Management
and Budget, 725 17th St., NW, Washington, DC 20503, marked ``Attention:
Desk Officer for EPA.'' Include the ICR number in any correspondence.
Since OMB is required to make a decision concerning the ICR between 30
and 60 days after April 21, 2000, a comment to OMB is best assured of
having its full effect if OMB receives it by May 22, 2000. The final
rule will respond to any OMB or public comments on the information
collection requirements contained in this notice.
Dated: April 12, 2000.
J. Charles Fox,
Assistant Administrator for Water.
[FR Doc. 00-9655 Filed 4-20-00; 8:45 am]
BILLING CODE 6560-50-P