[Federal Register Volume 65, Number 58 (Friday, March 24, 2000)]
[Proposed Rules]
[Pages 16094-16109]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-7323]
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Part VII
Environmental Protection Agency
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40 CFR Part 755
Methyl Tertiary Butyl Ether (MTBE); Advance Notice of Intent To
Initiate Rulemaking Under the Toxic Substances Control Act To Eliminate
or Limit the Use of MTBE as a Fuel Additive in Gasoline; Advance Notice
of Proposed Rulemaking
Federal Register / Vol. 65, No. 58 / Friday, March 24, 2000 /
Proposed Rules
[[Page 16094]]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 755
[OPPT-62164; FRL-6496-1]
Methyl Tertiary Butyl Ether (MTBE); Advance Notice of Intent to
Initiate Rulemaking Under the Toxic Substances Control Act to Eliminate
or Limit the Use of MTBE as a Fuel Additive in Gasoline
AGENCY: Environmental Protection Agency (EPA).
ACTION: Advance Notice of Proposed Rulemaking.
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SUMMARY: Methyl Tertiary Butyl Ether (MTBE) is a chemical compound that
is used as a fuel additive in gasoline. Refiners have primarily added
MTBE to gasoline to meet the Clean Air Act (CAA) requirement that areas
with severe problems in attaining the National Ambient Air Quality
Standard (NAAQS) for ozone use Reformulated Gasoline (RFG) containing
2% oxygen by weight. Many States have also voluntarily chosen to use
RFG as a means of addressing marginal, moderate, or serious ozone
nonattainment, and some refiners use MTBE to boost the octane of
gasoline. In addition to the RFG program, the CAA also required the
establishment of a Wintertime Oxygenated Fuel (Wintertime Oxyfuel)
program. Under this program, gasoline must contain 2.7% oxygen by
weight during the wintertime in areas that are not in attainment for
the NAAQS for carbon monoxide (CO). In some cases this requirement is
met through the use of MTBE. While the use of MTBE as a fuel additive
in gasoline has helped to reduce harmful air emissions, it has also
caused widespread and serious contamination of the nation's drinking
water supplies. Unlike other components of gasoline, MTBE dissolves and
spreads readily in the groundwater underlying a spill site, resists
biodegradation, and is difficult and costly to remove from groundwater.
Low levels of MTBE can render drinking water supplies unpotable due to
its offensive taste and odor. At higher levels, it may also pose a risk
to human health. The United States Geological Survey (USGS) has found
that the occurrence of MTBE in groundwater is strongly related to its
use as a fuel additive in the area, finding detections of MTBE in 21%
of ambient groundwater tested in areas where MTBE is used in RFG
compared with 2% of ambient groundwater in areas using conventional
gasoline. EPA is today providing an advance notice of its intent to
initiate a rulemaking pursuant to section 6 of the Toxic Substances
Control Act (TSCA) to eliminate or limit the use of MTBE as a fuel
additive. EPA seeks public comment on a number of aspects of this
anticipated regulatory action, including whether the Agency should take
action to address any fuel additives other than MTBE.
DATES: Comments, identified by docket control number OPPTS-62164, must
be received on or before May 8, 2000.
ADDRESSES: Comments may be submitted by mail, electronically, or in
person. Please follow the detailed instructions for each method as
provided in Unit I. of the SUPPLEMENTARY INFORMATION. To ensure proper
receipt by EPA, it is imperative that you identify docket control
number OPPTS-62164 on the first page of your response.
FOR FURTHER INFORMATION CONTACT: For general information contact:
Barbara Cunningham, Director, Office of Program Management and
Evaluation, Office of Pollution Prevention and Toxics (7401),
Environmental Protection Agency, Ariel Rios Bldg., 1200 Pennsylvania
Ave., NW., Washington, DC 20460; telephone number: (202) 554-1404; e-
mail address: [email protected].
For technical information contact: Karen Smith, Office of
Transportation and Air Quality, Fuels and Energy Division (6406J),
Environmental Protection Agency, Ariel Rios Bldg., 1200 Pennsylvania
Ave., NW., Washington, DC 20460; telephone number: (202) 564-9674; e-
mail address: [email protected].
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does this Action Apply to Me?
Entities potentially regulated by a limit or ban on the use of MTBE
as a fuel additive in gasoline are those entities that refine, import,
or blend gasoline with additives, or that transport, store, or sell
gasoline, or otherwise introduce gasoline into commerce. Potentially
regulated categories include:
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Examples of
Categories NAICS SIC codes regulated
codes entities
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Industry 324110 2911 Petroleum
refiners,
blenders, and
importers
Industry 422710 5171 Gasoline
422720 5172 marketers and
distributors
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This listing is not intended to be exhaustive, but rather provides
a guide for readers regarding entities likely to be regulated by an
action resulting from this ANPRM. Other types of entities not listed in
this table could also be directly affected, particularly if future
action includes limits directed at gasoline release prevention or water
remediation, rather than the MTBE content of gasoline. The North
American Industrial Classification System (NAICS) and Standard
Industrial Classification (SIC) codes have been provided to assist you
and others in determining whether or not this action applies to certain
entities. To determine whether you or your business is affected by this
action, you should carefully examine this ANPRM. If you have any
questions regarding the applicability of this action to a particular
entity, consult the technical person listed under FOR FURTHER
INFORMATION CONTACT.
B. How Can I Get Additional Information, Including Copies of this
Document or Other Related Documents?
1. Electronically. You may obtain electronic copies of this
document, and certain other related documents that might be available
electronically, from the EPA Internet Home Page at http://www.epa.gov/.
To access this document, on the Home Page select ``Laws and
Regulations'' and then look up the entry for this document under the
``Federal Register--Environmental Documents.'' You can also go directly
to the Federal Register listings at http://www.epa.gov/fedrgstr/.
2. In person. The Agency has established an official record for
this action under docket control number OPPTS-62164. The official
record consists of the documents specifically referenced in this ANPRM,
any public comments received during an applicable comment period, and
other information related to this action, including any information
claimed as Confidential
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Business Information (CBI). This official record includes the documents
that are physically located in the docket, as well as the documents
that are referenced in those documents and in this ANPRM. The public
version of the official record does not include any information claimed
as CBI. The public version of the official record, which includes
printed, paper versions of any electronic comments submitted during an
applicable comment period, is available for inspection in the TSCA
Nonconfidential Information Center, North East Mall, Rm. B-607,
Waterside Mall, 401 M St., SW., Washington, DC. The Center is open from
noon to 4 p.m., Monday through Friday, excluding legal holidays. The
telephone number for the Center is (202) 260-7099. For additional
information related to this ANPRM, see the Office of Air and Radiation
(OAR) Docket, A-99-01, The Blue Ribbon Panel to Review the Use of
Oxygenates in Gasoline. The index for OAR docket A-99-01 can be found
at http://www.epa.gov/oms/consumer/fuels/oxypanel/blueribb.htm.
3. Fax-on-Demand. Using a faxphone call (202) 401-0527 and select
item 4005 for an index of items in this category.
C. How and to Whom Do I Submit Comments?
You may submit comments through the mail, in person, or
electronically. To ensure proper receipt by EPA, it is imperative that
you identify docket control number OPPTS-62164 on the first page of
your response. Commenters should be aware that their comments may be
placed on an Internet docket web site. This information may include the
commenters name and address.
1. By mail. Submit your comments to: Document Control Office
(7407), Office of Pollution Prevention and Toxics (OPPT), Environmental
Protection Agency, Ariel Rios Bldg., 1200 Pennsylvania Ave., NW.,
Washington, DC 20460.
2. In person or by courier. Deliver your comments to: OPPT Document
Control Office (DCO) in East Tower Rm. G-099, Waterside Mall, 401 M
St., SW., Washington, DC. The DCO is open from 8 a.m. to 4 p.m., Monday
through Friday, excluding legal holidays. The telephone number for the
DCO is (202) 260-7093. If your comments are received after 3 p.m., they
will be dated as received the next business day.
3. Electronically. You may submit your comments electronically by
e-mail to: ``[email protected],'' or mail your computer disk to the
address identified above. Do not submit any information electronically
that you consider to be CBI. Electronic comments must be submitted as
an ASCII file avoiding the use of special characters and any form of
encryption. Comments and data will also be accepted on standard disks
in WordPerfect 6.1/8.0 or ASCII file format. All comments in electronic
form must be identified by docket control number OPPTS-62164.
Electronic comments may also be filed online at many Federal Depository
Libraries.
D. How Should I Handle CBI Information That I Want to Submit to the
Agency?
Do not submit any information electronically that you consider to
be CBI. You may claim information that you submit to EPA in response to
this document as CBI by marking any part or all of that information as
CBI. Information so marked will not be disclosed except in accordance
with procedures set forth in 40 CFR part 2. In addition to one complete
version of the comment that includes any information claimed as CBI, a
copy of the comment that does not contain the information claimed as
CBI must be submitted for inclusion in the public version of the
official record. Information not marked confidential will be included
in the public version of the official record without prior notice. If
you have any questions about CBI or the procedures for claiming CBI,
please consult the technical person identified under FOR FURTHER
INFORMATION CONTACT.
E. What Should I Consider as I Prepare My Comments for EPA?
EPA invites you to provide your views on any issue relevant to this
ANPRM. EPA has identified particular subjects in Unit VI. regarding
which comment would be particularly appreciated. You may find the
following suggestions helpful for preparing your comments:
1. Explain your views as clearly as possible.
2. Describe any assumptions that you used.
3. Provide copies of any technical information and/or data you used
that support your views.
4. If you estimate potential burden or costs, explain how you
arrived at the estimate that you provide.
5. Provide specific examples to illustrate your concerns.
6. Offer alternative ways to address the concerns identified by
EPA.
7. Make sure to submit your comments by the deadline in this ANPRM.
8. To ensure proper receipt by EPA, be sure to identify the docket
control number assigned to this action on the first page of your
response. You may also provide the name, date, and Federal Register
citation.
II. Introduction
This ANPRM initiates an Agency rulemaking to address the threat to
the nation's drinking water resources from contamination by MTBE, a
widely used additive in gasoline. This rulemaking will be conducted
under TSCA section 6, 15 U.S.C. 2605. It is EPA's intent to conduct
this rulemaking as quickly as reasonably practicable. EPA's review of
existing information on contamination of drinking water resources by
MTBE indicates substantial evidence of a significant risk to the
nation's drinking water supply. A comprehensive approach to such risk
must include consideration of either reducing or eliminating the use of
MTBE as a gasoline additive. As a result, EPA is initiating this
process pursuant to the unreasonable risk provision under TSCA section
6 to eliminate or greatly reduce the use of MTBE as a gasoline
additive. EPA is interested in comments on both the risk and these
possible responses to it.
MTBE is a common and widely used additive in gasoline. It is an
oxygenate, meaning it increases the oxygen content of the gasoline. It
is also a source of octane in gasoline. It is widely used in those
parts of the country where oxygenated gasoline is required, either by
Federal or State law. For example, the 1990 amendments to the CAA
require that Federal RFG meet a 2.0% oxygen content requirement by
weight. MTBE is the primary oxygenate used by refiners to meet this
requirement, which applies to over 30% of the country's gasoline. When
MTBE is used to meet this requirement, the gasoline is blended so it
contains about 11% MTBE by volume. In other parts of the country, MTBE
is sometimes used in conventional or non-RFG as a source of octane.
Significantly more MTBE is used in RFG and other oxygenated gasoline
programs than is used in conventional gasoline.
Current data on MTBE levels in ground and surface waters indicate
widespread and numerous detections at low levels of MTBE, with a more
limited number of detections at higher levels. Given MTBE's widespread
use as a gasoline additive and the large volumes of gasoline that are
stored, transported, and used in all areas of the country, releases of
MTBE to the nation's ground and surface waters occur in a number of
ways. Leakage from the gasoline storage and distribution system is a
major source of contamination, but the
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contamination can also come from spills, emissions from marine engines
into lakes and reservoirs, and to some extent from air deposition. MTBE
is highly soluble in water, resists biodegradation, and moves rapidly
with groundwater. It may end up in drinking water supplies even when
there are no indications of other gasoline components. MTBE is detected
in water much more often and at higher concentrations in areas of the
country where Federal RFG is sold, given its dominant use by refiners
as an oxygenate to meet the statutory RFG oxygen content requirement.
The USGS has found detections of MTBE in 21% of ambient groundwater
tested in areas where MTBE is used in RFG as compared with 2% of
ambient groundwater in areas using conventional gasoline. (Ref. 1)
The presence of MTBE in drinking water sources presents two major
problems. The first concern is that MTBE contamination may render water
supplies unuseable as drinking water. MTBE has an offensive taste and
odor which can be detected in water even at low levels. Because of the
taste and odor problem, MTBE contamination has resulted in the loss of
certain drinking water sources. For example, high levels of MTBE found
in groundwater wells that supply Santa Monica's drinking water led that
city to close its wells, forcing it to purchase drinking water from
another public water supplier. In addition, MTBE detections found in
groundwater wells that supply South Lake Tahoe forced the South Tahoe
Public Utility District to close 8 of its 34 wells despite detections
below EPA's advisory levels. An additional four wells were closed as a
precautionary measure due to their proximity to the existing MTBE
plumes.
The second major concern involves uncertainty regarding the level
of risk to public health from the chronic exposure of large numbers of
people to low levels of MTBE in drinking water. While inhalation of
MTBE in high concentrations has been shown to cause cancer in
laboratory animals, the Agency concluded in 1997 that there is little
likelihood that MTBE in drinking water would cause adverse health
effects at levels that cause taste and odor problems. (Ref. 2) There is
still much uncertainty about the extent of the health risks associated
with chronic, low-level exposures to MTBE in drinking water. The Agency
is continuing to review and update its analysis of the potential health
risks posed by MTBE.
Once MTBE contaminates a drinking water source, its chemical nature
makes it difficult, expensive, and time-consuming to remediate. For
example, it is much harder and more expensive to remove MTBE from
drinking water than it is to remove other organic components of
gasoline. Furthermore, MTBE does not biodegrade as readily as other
components of gasoline. Given the numerous and diverse sources of
potential release into the environment and the problems associated with
cleaning it up once it is released, EPA believes a comprehensive
approach to such risk must include consideration of either reducing or
eliminating the use of MTBE as a gasoline additive.
As discussed earlier, in ground water MTBE is more soluble, does
not adsorb as readily to soil particles, biodegrades less rapidly and
moves more quickly than other components of gasoline. By comparison,
unless frozen, MTBE in surface water will volatalize and find its way
into the atmosphere. This accounts for the less frequent and generally
lower concentrations of MTBE found in surface water.
Since the available information shows that there are numerous and
widespread instances of groundwater contamination, EPA is considering
the substitutes that would likely be used to replace MTBE. In
oxygenated gasoline programs such as Federal RFG, the most likely
substitute based on current usage is ethanol. Other ether compounds are
currently used as oxygenates in relatively small quantities. MTBE does
not occupy as dominant a position as an octane enhancer for
conventional gasoline as it does as an oxygenate in RFG. Ethanol,
alkylates, and aromatics are all widely-used as octane enhancers in
conventional gasoline. Although EPA is seeking more information on
alternatives to MTBE, EPA does not expect the use of ethanol,
alkylates, or aromatics as fuel additives to present the same magnitude
of risk to drinking water supplies as MTBE. Ethanol biodegrades more
quickly than MTBE, and therefore seems less likely to contaminate
drinking water as often as MTBE, or at the concentrations of MTBE.
First order degradation constants for MTBE in ambient ground water have
been reported by Schirmer and others (1998) and Borden and others
(1997). The rate constants, k, from these studies are 0.0012 day(-1)
(Schirmer and others, 1998) and 0.0010 +- 0.0007 day(-1) (Borden and
others, 1997). (Refs. 3,4) These reaction rates for MTBE correspond to
a half-life of about 1.6 and 1.9 years, respectively. By comparison, in
a December 1999 report to the California Environmental Policy Council
the authors report that under aerobic conditions, the reported half-
lives of ethanol in surface waters are short. Half-lives span 6.5 to 26
hours for ethanol. Anaerobic biodegradation in oxygen-limited
environments is also expected to proceed at rapid rates. Reported half-
lives for ethanol biodegradation under anaerobic conditions range from
1 to 4.3 days. (Ref. 5) Unlike MTBE, alkylates and aromatics are
expected to behave in soil and water more like other components
typically found in gasoline; as a result, they too would be unlikely to
contaminate drinking water as often as MTBE or at the concentrations of
MTBE. Ethers other than MTBE, and alcohols other than ethanol, are not
currently used widely as oxygenates; the Agency does not have much data
to characterize the risks they might pose to drinking water supplies.
However, the other ethers are chemically similar or related to MTBE,
and they may well move through soil and water in ways and amounts
similar to MTBE. EPA will closely evaluate whether compounds not
currently used in significant quantities as oxygenates in RFG might be
widely used as alternatives to MTBE, if MTBE use in gasoline is banned
or limited, whether additional information on these compounds is
necessary, and whether other measures are appropriate to assure that an
elimination or limitation of MTBE in gasoline does not result in the
use of alternatives that might cause a similar or greater level of
risk.
The remainder of this ANPRM outlines the major elements of the
problem and its potential solution. EPA invites comment from all
interested parties on these and any other matters relevant to
addressing the risk of MTBE to the nation's drinking water resources.
III. Background
A. What is MTBE and Why is it Used as a Fuel Additive?
MTBE is an ether compound made by combining methanol and
isobutylene. The methanol is typically derived from natural gas;
isobutylene can be derived as a byproduct of the petroleum refinery
process. Since the 1970's, MTBE has been used in the United States as
an octane-enhancing replacement for lead, primarily in mid- and high-
grade gasoline at concentrations as high as 7% (by volume). Now,
however, MTBE is mainly used as a fuel oxygenate at higher
concentrations (11% to 15% by volume) as part of the Federal RFG and
Wintertime Oxyfuel programs. These programs were initiated by EPA in
1995 and 1992, respectively.
The CAA mandates that RFG be sold in the 10 largest metropolitan
areas with
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the most severe summertime ozone levels, including Baltimore, Chicago,
Hartford, Houston, Los Angeles, Milwaukee, New York, Philadelphia,
Sacramento, and San Diego. The CAA also allows any other area
classified as a marginal, moderate, or serious ozone nonattainment area
to opt into the RFG program. Currently, 17 States and the District of
Columbia voluntarily participate in the RFG program. These areas are
located in California, Connecticut, Delaware, District of Columbia,
Illinois, Indiana, Kentucky, Maryland, Massachusetts, Missouri, New
Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Texas,
Virginia, and Wisconsin. The total number of areas participating in the
RFG program may change from year to year, depending on potential opt-
ins.
EPA regulations adopted pursuant to the CAA require that RFG
achieve reductions in mass emissions of volatile organic compounds
(VOCs) and toxic air emissions of at least 15% during Phase I of the
RFG program (1995 through 1999), and reductions in such emissions of
27% and 22%, respectively, during Phase II of the RFG program (2000 and
on). Phase II RFG also requires a 6.8% reduction in oxides of nitrogen
(NOX). RFG must also meet certain mandatory content
standards, including limitations on benzene and a restriction of heavy
metal content. To address its unique air pollution challenges,
California has adopted similar, but more stringent requirements for
California RFG.
The CAA specifies that RFG must contain 2% oxygen by weight.
Although a number of oxygenates could be used to meet this requirement,
in practice over 87% of RFG contains MTBE as the primary oxygenate;
approximately 12% of RFG contains ethanol. Two percent oxygen by weight
is equivalent to approximately 11% MTBE by volume. When ethanol is used
as an oxygenate, it is usually blended at 10% by volume, which is
equivalent to 3.5% oxygen by weight. A small percentage of refiners use
tertiary amyl methyl ether (TAME) as the primary oxygenate in RFG; more
frequently TAME is present in RFG as a secondary oxygenate together
with MTBE. Other oxygenates are available to refiners, such as ethyl
tertiary butyl ether (ETBE), tertiary butyl alcohol (TBA), and
diisopropyl ether (DIPE), but are not being used in significant
quantities (or at all) at this time.
Reformulated gasoline represents over 30% of the total retail
gasoline sold in the United States. According to the Department of
Energy (DOE), over 126 billion gallons of gasoline were supplied for
U.S. markets in 1998, with 41.5 billion gallons of that volume being
reformulated gasoline. (Ref. 6) In addition to the RFG program, certain
areas in California and elsewhere in the nation that have not attained
the NAAQS for CO are required under the CAA to implement the Wintertime
Oxyfuel program. The CAA requires Wintertime Oxyfuel to contain no less
than 2.7% oxygen (by weight) during the winter, when CO levels are
highest. There are 17 areas across the country that currently implement
the Wintertime Oxyfuel program. Ethanol is the primary oxygenate used
to meet this oxygen requirement. Currently, Los Angeles is the only
area implementing the Wintertime Oxyfuel program with MTBE. When MTBE
is used to meet the Wintertime Oxyfuel requirements, it is added to
gasoline at a concentration of approximately 15% by volume.
MTBE is also used in conventional gasoline to boost the octane of
gasoline. Octane is a measure of a fuel's resistance to uncontrolled
combustion (engine knock). The DOE estimates that approximately 12,000
barrels of MTBE are used per day as an octane enhancer in conventional
gasoline. (Ref. 7) This is less than 5% of the total MTBE use in
gasoline. MTBE is typically present in gasoline as an octane enhancer
at 3-7% by volume. Alternative octane enhancers are also used,
including ethanol, alkylates, and aromatic compounds.
A number of States have taken actions designed to limit the use of
MTBE in gasoline. In March 1999, Governor Gray Davis of California
issued an executive order requiring the California Air Resources Board
to develop a timetable for the removal of MTBE from gasoline sold in
California as soon as possible, but by no later than December 31, 2002.
Maine opted out of the RFG program in March 1999. In July of 1999, New
Hampshire enacted a law directed at reducing the use of MTBE in
gasoline, including a requirement that the State request a waiver from
EPA of RFG oxygen content requirements until 2002. Five other States
have initiated proposed limited use, bans or phase-outs of MTBE,
including Arizona, Kansas, Missouri, New York, and South Dakota.
B. What Risks Does MTBE Pose to Drinking Water Supplies?
1. Chemical properties. In comparison to other components of
concern in gasoline, including benzene, toluene, ethylbenzene, and
xylenes (collectively referred to as ``BTEX''), the available
information shows MTBE may pose additional problems when it escapes
into the environment through gasoline releases. MTBE is capable of
traveling through soil rapidly, is very soluble in water (much more so
than BTEX), and is highly resistant to biodegradation (much more so
than BTEX). MTBE that enters groundwater moves at nearly the same
velocity as the groundwater itself. As a result, it often travels
farther than other gasoline constituents, making it more likely to
impact public and private drinking water wells. Due to its affinity for
water and its tendency to form large contamination plumes in
groundwater, and because MTBE is highly resistant to biodegradation and
remediation, gasoline releases with MTBE can be substantially more
difficult and costly to remediate than gasoline releases that do not
contain MTBE (Unit III.E.). This is a substantial concern in the United
States, where approximately 40-46% of the population uses groundwater
as a source of drinking water.
2. Taste and odor. MTBE has a very unpleasant turpentine-like taste
and odor that at low levels of contamination can render drinking water
unacceptable for consumption. A number of studies have been conducted
on the concentrations of MTBE in drinking water at which individuals
can detect the taste and odor of the chemical. (Refs. 8,9,10) Human
sensitivity to taste and odor varies widely. In controlled studies,
some individuals were able to detect very low concentrations of MTBE,
while others do not taste or smell the chemical even at much higher
concentrations. In controlled studies individuals have detected odor
and taste at concentrations of MTBE as low as 2.5 parts per billion
(ppb) for odor and 2 ppb for taste.\1\
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\1\ Throughout this ANPRM, various studies are cited which may
refer to the presence of MTBE in water in either micrograms per
liter (g/L) or ppb. These units are approximately
interchangeable assuming the density of the water is constant. In
reality, to the extent that the water density may vary from study to
study, equivalence of these units may not be exact.
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In December 1997, EPA's Office of Water released a non-regulatory
advisory for MTBE in drinking water. The EPA advisory is not a
mandatory standard for action and is not Federally enforceable, but
provides guidance for communities that may be exposed to drinking water
contaminated with MTBE. According to the advisory, keeping MTBE
concentrations in the range of 20-40 g/L or below would likely
avert unpleasant taste and odor effects, recognizing that some people
may detect the chemical below this concentration range.
The State of California has chosen to establish a secondary
drinking water standard of 5 g/L to ensure the potability of
drinking water for more
[[Page 16098]]
sensitive individuals. EPA is planning to upgrade its MTBE advisory to
a national secondary drinking water standard and will review its 1997
advisory levels at that time. Secondary drinking water standards
address the aesthetic qualities that relate to public acceptance of
drinking water and are provided as non-enforceable guidance to the
States.
3. Human health effects. The majority of the human health-related
research conducted to date on MTBE has focused on adverse effects that
may result through inhalation of the chemical. At high doses by the
inhalation route, MTBE has caused non-cancer health effects as well as
tumors in two strains of rat and one strain of mouse in a variety of
organs. However, there have been no human or animal health effects
studies concerning the ingestion of MTBE in drinking water. In one
study, animals were given a daily (all at once) dose of MTBE in olive
oil. There were carcinogenic effects at a high level of exposure.
Because the animals were not exposed through drinking water,
uncertainties remain concerning the degree of risk associated with
typical human exposure.
EPA classified MTBE as a ``possible'' human carcinogen under its
1986 cancer risk assessment guidelines on the basis of results of
inhalation cancer tests and has suggested that it be regarded as posing
a potential carcinogenic hazard and risk to humans, although no
quantitative estimate of the cancer potency of MTBE has been
established by EPA because of limitations in the available data. (Refs.
11,12) While MTBE has been characterized as an animal carcinogen, both
the International Agency for Research on Cancer and the Department of
Health and Human Services have indicated that there are not enough data
to classify MTBE with regard to human carcinogenicity under their
classification schemes. (Refs. 13,14) It should be noted that
conclusions in the Office of Science and Technology Policy's 1997
Interagency Assessment of Oxygenated Fuels and in a 1996 report by the
Health Effects Institute generally support EPA's view on potential
carcinogenic hazard. (Ref. 15) The Interagency Assessment stated, in
regard to inhalation risks, that ``it is not known whether the cancer
risk of oxygenated gasoline containing MTBE is significantly different
from the cancer risk of conventional gasoline.'' The estimated upper
bound cancer units risks of MTBE are similar to or slightly lower than
those of fully vaporized conventional gasoline, which has been listed
by EPA as a probable human carcinogen based on animal carcinogenicity
data. However, because of lack of health data on the nonoxygenated
gasoline vapors to which humans are actually exposed, it is not
possible to have a reasonably good estimate of population cancer risk
to conventional gasoline.
As a result of substantial scientific uncertainties, a review
committee of the National Academy of Sciences (NAS) recommended that
additional studies be conducted on MTBE and that questions about the
bolus dosing study be resolved before the study is used for risk
assessment purposes. (Ref. 16) A number of ongoing studies by EPA, the
Chemical Industry Institute of Toxicology (CIIT) and other
organizations should provide EPA with information to assess health
risks via different routes of MTBE exposure. These studies should allow
for extrapolation from the inhalation studies to an assessment of risks
associated with ingestion of drinking water. In addition, further study
of potential health effects of MTBE and other fuel additives are
underway by the petroleum industry as required under CAA section 211.
EPA reviewed available health effects information on MTBE in its
1997 drinking water advisory guidance and determined that there was
insufficient information available on MTBE health effects and exposure
to allow EPA to establish a national primary drinking water regulation.
The drinking water advisory document indicated there is little
likelihood that MTBE concentrations between 20 and 40 g/L
would cause adverse health effects. Nevertheless, California and New
Hampshire have proposed health-based primary drinking water standards
of 13 g/L for MTBE.
C. How Widespread is the MTBE Contamination?
Each year approximately 9 million gallons of gasoline (the
equivalent of a full supertanker) are released to the environment in
the United States from leaks and spills, according to an estimate by
the Alliance for Proper Gasoline Handling. (Ref. 17) MTBE may be
present in a substantial portion of these releases. Because of MTBE's
solubility in water and resistance to degradation, it is being detected
with increasing frequency in both groundwater and surface water. The
potential for harm posed by MTBE releases can perhaps best be
understood by reviewing some well-documented case studies. The releases
of MTBE that occurred in these situations could have occurred, and
could be repeated, virtually anywhere in the United States. Larger-
scale studies document the widespread detection of MTBE in the nation's
water supplies.
1. Examples of MTBE contamination. The City of Santa Monica,
California, has historically relied on seven wells from the Arcadia and
Charnock well fields to provide approximately 50% of the drinking water
to the town's 87,000 residents. In August of 1995, the City found MTBE
in water derived from the Charnock Wellfield. By April of 1996, MTBE
levels had risen dramatically in all wells, with concentrations
reaching up to 610 ppb. All five of the city's Charnock wells were shut
down in 1996. The Southern California Water Company (SCWC), which had
withdrawn drinking water from the Charnock well field, also closed its
two production wells to avoid drawing contamination into the wells. The
SCWC Charnock wells had provided a portion of the drinking water for
10,000 residences in Culver City, California. After completion of
screening level investigations at 28 underground storage tanks (USTs)
locations and two gasoline product pipelines, the EPA and the Los
Angeles Regional Water Quality Control Board (RWQCB) identified 25 USTs
as contributing contamination to the Charnock Sub-Basin, the
groundwater basin which supplies water to the Charnock Wellfields. From
1997-1999, three companies potentially responsible for the
contamination voluntarily conducted testing of wellhead drinking water
treatment technologies, performed regional groundwater investigation
activities, and reimbursed the City of Santa Monica and Southern
California Water Company for water replacement costs. These companies
claim to have spent over $50 million on response activities to date.
Since 1996, the city and SCWC have met their municipal water demand by
utilizing water purchased from the Metropolitan Water District, at a
cost of over $3 million per year. Together with the Agencies' oversight
cost and the costs of investigation and cleanup at all the UST
locations and gasoline product pipelines, it is estimated that over $60
million in response costs have been expended in addressing the Charnock
Wellfield problem to date. In September 1999, EPA and RWQCB issued
orders to potentially responsible parties that require them to pay for
replacement water for the affected homeowners from January 2000 until
January 2005. A final cleanup is expected to cost more than $160
million.
Contamination of the Arcadia field was traced to a single gas
station. The gas station was demolished,
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underground tanks and lines were removed, and approximately 2,000 cubic
yards of gasoline-containing soils were excavated. Cleanup crews are
now working to control and remove additional sources of contamination
from the area. In addition, a shallow groundwater pump and treat system
was installed in October 1997 to control further migration of the
contaminated groundwater. The extracted water is filtered through three
carbon beds to remove the bulk of MTBE before the water is discharged
into the sanitary sewer. Actions are currently underway to begin
additional treatment of water from the Arcadia wells with carbon and
eventually obtain a permit to serve the water as drinking water.
In Glennville, California, residential drinking wells were
contaminated with MTBE at levels up to 20,000 ppb. The likely source of
the contamination was an UST and associated piping at the town's only
gas station. The town was forced to start using an alternative drinking
water source in 1997, and still relies on alternative sources of water.
In Whitefield, Maine, an automobile gasoline leak of 20 gallons or
less contaminated a bedrock drinking water well for an elementary
school with MTBE to a level of 900 g/L. According to a report
by the the Northeast States for Coordinated Air Use Management
(NESCAUM), the State of Maine traced the source of the spill to an area
about 120 feet from the well where cars were parked on the grass. (Ref.
18)
In December 1997, a car accident in Standish, Maine, led to the
release of 8 to 10 gallons of gasoline that contaminated 24 nearby
private wells. Eleven wells were contaminated with MTBE to a level
above 35 g/L; two were contaminated at over 1,000 g/
L; and the well nearest the accident site contained the highest
concentration of 6,500 g/L. When the State discovered the
contaminated wells in May 1998, it removed 79 cubic yards of
contaminated soil. The contamination extended to the top of the
underlying bedrock at a depth of 9 feet below the surface. (Ref. 19)
In the town of Windham, Maine, two public water supply wells 900 to
1,100 feet from underground gasoline tanks were contaminated to levels
of 1 to 6 g/L MTBE. According to a NESCAUM report, the tanks
were state-of-the-art technology, double walled and only 10 months old
when the MTBE contamination was discovered. (Ref. 20) Extensive testing
showed that the tanks did not leak directly to the ground, nor were any
vapor leaks found after extensive testing. NESCAUM stated that the only
plausible cause of the contamination was gasoline overfills. The amount
spilled was estimated to be 10 to 40 gallons.
MTBE has also been detected in surface waters of lakes and
reservoirs. A University of California, Davis, study was conducted at
Donner Lake, California. (Ref. 21) The lake is a source of drinking
water for lakeside residents and contributes to the drinking water
supply of downstream communities, such as Reno, Nevada. MTBE levels
were low during winter months, at just above the 0.1 g/L level
of detection. Levels increased dramatically during the summer boating
season to a high of 12.1 g/L. Following Labor Day, boat use
declined dramatically, as did MTBE levels. Volatilization between the
air/water interface appeared to be the major avenue for loss of MTBE.
In Shasta Lake, a large recreational-use reservoir in northern
California, MTBE concentrations were reported to range from 9-88
g/L over the Labor Day 1996 weekend. Maximum values were
associated with large boats entering a docking area or with engine
exhaust from those boats. MTBE was also measured in a temporary lake
constructed in southern California for a jetski event in the summer of
1996. After the 3-day event, concentrations reportedly ranged from 50-
60 g/L.
On January 28, 2000, a tanker truck rolled over on Route 110 in
Lowell, Massachusetts, releasing approximately 11,000 gallons of
gasoline. Most of the gasoline entered the Merrimack River. The cities
of Tewksbury, Methuen, and Lawrence each have drinking water intakes on
the River downstream of the spill site. Although contaminants were not
detected at the drinking water treatment plants the night of the spill,
later samples indicated elevated levels of MTBE. The cities of
Tewksbury and Lawrence temporarily closed their drinking water
treatment facilities and purchased water from alternative sources; the
treatment facility in Methuen remained open. MTBE levels dropped
significantly after a few days, and the facilities were advised that
they could safely use their intakes.
2. Large-scale studies. Although scattered incidents of localized
water contamination by MTBE have been reported since the early 1980s,
the first report to suggest that MTBE contamination of water might be
occurring on a widespread basis came as a result of the sampling of
ambient groundwater conducted by the USGS National Water Quality
Assessment Program (NAWQA). Ambient groundwater is groundwater where
there are no known point sources of contamination prior to sampling in
drinking water and non-drinking water wells. In an initial report of
sampling conducted in shallow groundwater in 1993 and 1994, USGS
reported that of 210 sampled wells and springs in 8 urban areas, 56
(27%) contained MTBE at a minimum reporting level of 0.2
g/L, and 3% of the wells and springs had MTBE
concentrations exceeding 20 g/L. (Ref. 22) The maximum
concentration of MTBE detected in these urban areas was over 100
g/L.
The USGS collected data in 1995 from additional wells in urban
areas and combined them with data from 1993-1994 to provide specific
information on drinking water aquifers. This analysis showed MTBE
detections in 12 (14%) of 83 shallow urban wells located in aquifers
supplying drinking water and in 19 (2%) of 949 rural wells in aquifers
used for drinking water, with a median concentration of approximately
0.50 g/L. (Ref. 23)
Finally, in a 1999 publication in the Proceedings of the 1999 Water
Resources Conference of the American Water Works Association, USGS
assembled its early ambient groundwater data with additional data from
urban and rural wells. (Ref. 24) For urban areas, the frequency of
detection of MTBE in groundwater in areas of substantial MTBE use was
about 27% (49 of 184 wells), whereas frequency of detection in non-
substantial use areas was about 5%. In rural areas, the frequency of
detection of MTBE in areas of substantial MTBE use was about 17% (50 of
298 wells), whereas the frequency of detection in non-substantial use
areas was about 2%. Overall, USGS found detections of MTBE in 21% of
ambient groundwater tested in areas where MTBE is used in RFG compared
with 2% of ambient groundwater in areas using conventional gasoline. In
contrast, BTEX was found in only 4% of areas where RFG or winter
oxyfuels were used. (Ref. 25)
Preliminary results from a joint USGS/EPA study of 12 northeastern
States (with a detection limit of 1.0 g/L) show that MTBE was
detected in 7% of drinking water supplies, with 0.8% of these
detections above 20 g/L. (Ref. 26) The study also concluded
that MTBE is detected five times more frequently in drinking water from
community water systems in RFG or Winter Oxyfuel areas than in non-RFG
or non-Winter Oxyfuel areas. The study showed BTEX detections in 8.3%
of the systems analyzed (2,097 systems). Although collectively BTEX was
found at approximately the same frequency as MTBE, there is very little
co-occurrence of the BTEX compounds with MTBE (less than 1% of the
systems). This may indicate that MTBE separated from the
[[Page 16100]]
rest of the contaminants in the original gasoline plumes, but it also
indicates that the increased use of MTBE since 1995 may have created a
new universe of contaminated water supplies.
In 1998, the State of Maine reported on sampling conducted on 951
household drinking water wells and 793 public water supplies. (Ref. 27)
The study was designed to be statistically representative of the entire
State. MTBE was detected in 150 (15.8%) of the sampled household wells
at a minimum reporting level of 0.1 g/L, and 1.1% of the wells
contained MTBE levels exceeding 35 g/L. The Maine report
projected that approximately 1,400-5,200 private wells across the State
could be contaminated at levels exceeding 35 g/L. For public
water systems sampled, 125 (16%) showed detectable levels of MTBE, 48
(6.1%) between 1 g/L and 35 g/L, and no samples above
35 g/L.
In another study reported in 1998, the American Water Works Service
Company collected data from drinking water wells in 16 States. (Ref.
28) Forty-four (2%) of 2,120 samples from 17 (4%) of 450 wells tested
positive for MTBE at a minimum reporting level of 0.2 g/L,
with the highest concentration at 8 g/L.
In a 1998 industry study of 700 service stations known to have
released gasoline, MTBE was detected at 83% of the sites, with about
43% of the sites having MTBE concentrations greater than 1,000
g/L. (Ref. 29) A large percentage (76%) of station sites
sampled in Florida showed MTBE contamination, even though Florida does
not participate in the RFG or winter oxyfuel programs. It is assumed
that MTBE was used as an octane enhancer in gasoline released from
Florida service stations.
An EPA-supported survey of the 50 States and District of Columbia
in 1998 found that, of the 34 States that acquire MTBE data from
leaking underground storage tank (LUST) sites, 27 (79%) indicated that
MTBE was present at more than 20% of their sites, and 10 (29%) reported
MTBE at more than 80% of their sites. (Ref. 30) The survey also asked
about contamination of drinking water wells. Of the 40 State programs
that responded, 25 (51%) had received reports of private wells
contaminated with MTBE. In addition, 19 (39%) of the programs reported
public drinking water wells contaminated with MTBE. Five of the States
responding to the survey reported that MTBE was detected in groundwater
at LUST sites where the product released was not gasoline. MTBE
concentrations of greater than 20 g/L in groundwater had
occurred as the result of releases of diesel fuel, jet fuel, heating
oil, aviation fuel, and waste oil. Apparently, MTBE cross-contaminated
other petroleum products during transport and distribution. A study of
fuel releases in Connecticut (Ref. 31) provides further evidence of
MTBE contamination of heating oil. In this study, 27 heating oil
release sites resulted in MTBE contamination of groundwater with
concentrations ranging from 1 to 4,100 g/L. At the site with
the highest concentration of MTBE in groundwater, MTBE was measured in
the heating oil at a concentration of 14 milligram/Liter (mg/L).
Individual case studies suggest that, depending on the hydrogeology
of the site, significant MTBE contamination of water supplies could
occur and is costly and time-consuming to remedy. The large-scale
studies indicate that MTBE releases have occurred in many places, with
documented detections in public and private drinking water sources.
D. What are the Major Sources of MTBE Contamination and How are They
Currently Regulated?
As a large industrialized nation, the United States produces,
distributes, and consumes extensive quantities of gasoline, and much of
that gasoline contains MTBE. The DOE estimates that in 1998, over 126
billion gallons of gasoline were sold in the United States (Ref. 32)
RFG represented 41.5 billion gallons of that total, with the vast
majority containing MTBE as the primary oxygenate. After production in
the United States or import, gasoline may travel through thousands of
miles of pipelines, or be transported by truck, to any of roughly
10,000 terminals and bulk stations. From there it may be distributed to
one of 180,000 retail outlets and fleet storage facilities, or to any
of hundreds of thousands of above-ground or underground tanks at farms,
industrial facilities, businesses, and homes. Finally, gasoline is
removed from bulk storage into individualized storage units associated
with such products as cars, trucks, boats, planes, lawn mowers, brush
cutters, and chain saws. Residual gasoline in transport conduits may
contaminate different types of fuels (e.g., home heating oil) that is
transported through the same conduits at different times. Although this
does not normally cause problems, it may explain why MTBE has been
found in releases of home heating oil and other fuels. There are
opportunities for leaks wherever gasoline (or a product containing
gasoline) is stored, and there are opportunities for spills whenever
fuel is transported or transferred from one container to another.
Although many Federal and State programs have been developed to
minimize the potential for leaks and spills from the vast array of
units and individuals handling gasoline, no system involving so much
product and so many individual handlers can be foolproof. Gasoline is
released to the environment every day; these releases can be expected
to continue and MTBE, being more soluble and less biodegradable than
BTEX, will move more quickly and at higher concentrations than the
other components of gasoline, making its way to surface water and
groundwater resources. This unit describes the major sources of
gasoline leaks, and summarizes regulatory programs applicable to them.
1. Underground storage tanks. There are an estimated 760,000 USTs
currently in use for petroleum storage in the United States that are
subject to regulation under Subtitle I of the Resource Conservation and
Recovery Act (RCRA), 42 U.S.C . 6991a-i. These tanks have a storage
capacity of approximately 6 billion gallons. In addition, there are
approximately 3 to 4 million USTs storing fuel that are exempt from
RCRA Subtitle I regulation including:
a. Farm and residential tanks of 1,100 gallons or less capacity
holding motor fuel for noncommercial purposes.
b. Tanks storing heating oil used on the premises where it is
stored.
c. Tanks on or above the floor of underground areas, such as
basements or tunnels.
d. Septic tanks and systems for collecting storm water and
wastewater.
e. Flow-through process tanks.
f. Tanks of 110 gallons or less capacity.
g. Emergency spill and overfill tanks.
Leaking USTs have been identified as the likely sources of a number
of the more problematic releases of MTBE to the environment, including
releases that have closed water supplies in Santa Monica and
Glennville, California. In California alone, the minimum number of MTBE
point sources from leaking UST sites is estimated at greater than
10,000.
In 1988, EPA issued regulations setting minimum standards for RCRA
Subtitle I-regulated UST systems. Existing UST systems, those installed
on or before December 22, 1988, had until December 22, 1998, to upgrade
with spill, overfill, and corrosion protection, properly close, or meet
new tank performance standards. Any UST system installed after December
22, 1988, had to meet new tank performance standards for spill,
overfill,
[[Page 16101]]
and corrosion protection at the time of installation. Based on reports
received as of the end of September 1999, EPA estimates that
approximately 85% of the RCRA-regulated universe of UST systems
currently meet EPA's upgrade or new tank requirements. By the end of
2000, EPA expects that approximately 90% of RCRA-regulated USTs will be
in compliance, leaving approximately 70,000 substandard USTs.
The Federal regulations also require that UST systems have release
detection equipment to identify releases to the environment. The
regulations required that all owners and operators install and properly
operate a method of release detection no later than 1993 based on the
age of the UST system. While virtually all UST systems are equipped
with leak detection equipment, they are not necessarily installed or
operated properly. Largely as a result of problems with proper
operation of leak detection equipment, EPA estimates that approximately
60% of UST systems are in compliance with the leak detection
requirements. By the end of 2005, EPA expects compliance with the leak
detection requirements will be 90%.
EPA provides funding (through the Leaking Underground Storage Tank
Trust Fund) to States to oversee the cleanup of releases from USTs.
Since the UST program began, approximately 400,000 releases from USTs
have been confirmed; of that number, approximately 230,000 cleanups
have been completed. While not every State is testing for MTBE at UST
release sites, those that do have found MTBE at most, if not all,
release sites. In response to a recommendation by the Blue Ribbon Panel
(the Panel), EPA recently sent a memo to all State UST programs
recommending that they monitor for and report MTBE in groundwater at
all leaking UST sites.
Those facilities that have a total underground oil storage capacity
of more than 42,000 gallons, and which are located such that they could
reasonably be expected to discharge oil into navigable waters or
adjoining shorelines, are subject to EPA requirements for the
development of Spill Prevention, Control and Countermeasure (SPCC)
Plans pursuant to Clean Water Act (CWA) section 311(j)(1)(C). An SPCC
plan is a detailed, facility-specific description of how the facility
will comply with EPA regulatory requirements for secondary containment,
facility drainage, dikes or barriers, sump and collection systems,
retention ponds, curbing, tank corrosion protection systems, and liquid
level devices (40 CFR 112.1-112.7). To avoid duplicative regulation
under the RCRA and CWA section 311 programs, EPA proposed in 1991 to
exempt from SPCC requirements those completely buried tanks that are
subject to RCRA Subtitle I requirements. EPA expects to issue a final
rule dealing with this and other modifications to the SPCC program
later in 2000.
It is important to understand that even after USTs are in full
compliance with the RCRA and CWA section 311 requirements, some
releases are expected to occur as a result of improper installation or
upgrading, improper operation and maintenance, and accidents.
2. Above-ground storage tanks. EPA regulates under the CWA section
311 SPCC program approximately 440,000 facilities with above-ground
storage tanks (ASTs) that are located so as to be reasonably expected
to discharge oil to surface waters or adjoining shorelines. A facility
is regulated if it has an AST with a capacity of more than 660 gallons,
or multiple ASTs with a combined capacity of more than 1,320 gallons.
ASTs are also subject to EPA's more general requirements for the
reporting of oil spills to navigable waters, 40 CFR part 110, and EPA's
prohibition on the discharge to navigable waters of oil in quantities
that will:
a. Violate applicable water quality standards.
b. Cause a sheen on the waters.
c. Cause a sludge or emulsion to be deposited beneath the surface
of the water or adjoining shoreline (40 CFR 110.3).
Despite EPA's regulatory programs, almost 20,000 oil spills to
navigable water (from all sources, including tank trucks, barges, etc.)
are reported each year. About half, or 10,000 spills, occur annually to
the inland zone over which EPA has jurisdiction, while the other half
occurs in the coastal zone over which the Coast Guard exercises
jurisdiction.
3. Pipelines. Excluding intrastate pipelines and small gathering
lines associated with crude oil production fields, there are
approximately 160,000 miles of liquids pipelines in the United States.
These pipelines transport approximately 525 billion gallons of crude
oil and refined products annually. The Department of Transportation
(DOT) estimates that, over a recent 5-year period (1994-1998), an
average of 29 gasoline spills occurred annually from pipelines, with
the total volume of gasoline released from pipelines averaging 1.03
million gallons per year. While there are little or no data on the
extent of MTBE releases from pipelines, MTBE is expected to be present
in some portion of the refined product in the pipelines.
In California, pipeline release data are currently being compiled
by the Office of the State Fire Marshal, which regulates approximately
8,500 miles of pipelines. Since 1981, there have been approximately 300
pipeline releases within the State Fire Marshal's Jurisdiction. (Ref.
33)
Pipelines are regulated by the DOT, Research and Special Programs
Administration (RSPA). Under authority of the Pipeline Safety Act of
1992, 49 U.S.C. 60101 et seq., DOT has established minimum safety
standards for pipelines carrying hazardous liquids, including petroleum
and petroleum products (49 CFR part 195). Under authority of CWA
section 311, DOT also requires response planning for pipelines that,
because of their location, could reasonably be expected to cause
substantial harm to the environment by discharging oil into or on the
navigable water, adjoining shorelines, or the exclusive economic zones
(49 CFR part 194).
4. Other releases. Releases from automobile accidents, tank truck
spills, consumer disposal of ``old'' gasoline, and spills during
fueling operations have been identified as sources of contamination of
drinking water wells. The incidents in Maine, described in Unit
III.C.1. are examples of how relatively small spills can result in
contamination of nearby drinking water supplies. Home heating oil
storage tanks have also been identified as potential sources of MTBE
contamination, as MTBE might be present from mixing the heating oil
with small volumes of gasoline in the bulk fuel distribution or tank
truck delivery systems. Other data on releases of this type are not
available, and EPA is not aware of any efforts currently underway to
further characterize these sources of MTBE contamination.
EPA regulatory programs do not address small episodic releases of
gasoline unless they result in a discharge to surface waters. For those
releases, the spill must be reported, and the responsible party may be
penalized for any violation of EPA's oil discharge prohibition. In the
many cases involving accidental spills, however, these requirements are
not effective in preventing releases.
5. Watercraft. Gasoline-powered watercraft have contributed to the
contamination of lakes and reservoirs with MTBE. The two-stroke engines
commonly used for certain watercraft can discharge up to 30% of each
gallon of gasoline as unburned hydrocarbons. (EPA issued a final rule
to reduce the
[[Page 16102]]
amount of air emissions from new gasoline-powered watercraft and
outboard motors which will be phased-in beginning in 1998, and
completed in the 2006 model year. This rule is also expected to reduce
the release of unburned hydrocarbons from new engines into surface
waters. This rulemaking published in the Federal Register of October 4,
1996 (61 FR 52088) (FRL-5548-8), which applies only to new engines,
will reduce hydrocarbon emissions by 75%. The State of California
requires that EPA's new standards be fully implemented by 2001). As
described in Unit III.C.1., concentrations of MTBE in lakes with
significant recreational boating tend to peak in the boating season at
levels that can be a concern for taste and odor, and possibly human
health, and decrease fairly rapidly after the boating season has ended.
Volatilization at the air/water surface is considered the dominant
mechanism for this removal process.
Although most discharges of pollutants from point sources (e.g.,
pipes and other discrete conveyances) to surface waters must be
authorized under CWA section 402 by a National Pollutant Discharge
Elimination System (NPDES) permit, discharges from properly functioning
marine engines are currently subject to a regulatory exemption from
this requirement (40 CFR 122.3 (a)).
6.Storm water runoff. Storm water runoff becomes contaminated with
MTBE from the dissolution of residual MTBE from parking lots and
roadways, as well as from atmospheric washout during precipitation
events. The USGS has characterized MTBE concentrations in runoff in
many areas and has found such contamination typically to be lower than
2 ppb. (Ref. 34) The National Science and Technology Council's 1997
Interagency Assessment of Oxygenated Fuels Report describes storm water
runoff as exhibiting concentrations of 0.2-8.7 ppb in 7% of the samples
tested in 16 cities from 1991 to 1995. (Ref. 35) Most detections in
this study were in the Denver area, where implementation of the
Wintertime Oxyfuel program began in 1988. Based on predictive modeling,
concentrations in rainwater (in g/L) are expected to be
equivalent to the surrounding air concentrations (in ppb, volume). MTBE
air concentrations tend to be less than 1 ppb in urban areas, leading
to predicted rainwater levels of 1 g/L or less. However,
rainwater around localized areas of high MTBE air concentrations (e.g.,
parking garages) could contain correspondingly higher levels of MTBE.
Storm water may be discharged to surface water or percolate to
groundwater, and thus serves as a continuing source of low-level MTBE
contamination of these potential drinking water sources.
Clean Water Act NPDES permit requirements apply to certain
discharges of storm water which may contain MTBE. Though many
discharges of storm water are not subject to permit requirements, NPDES
permits are required for industrial storm water discharges, discharges
from municipal separate storm sewer systems, and storm water discharges
specifically designated by EPA or authorized NPDES States. Although
MTBE is not typically targeted in these permits, the best management
practices and planning requirements usually specified are likely to
reduce MTBE discharges through storm water.
As this summary demonstrates, there are a number of programs in
place to minimize or mitigate the effects of gasoline releases.
However, in light of the volume of gasoline used and the myriad
opportunities for leaks, spills, and accidents, substantial releases of
gasoline are likely to continue to occur in the future.
E. How Practical is it to Cleanup Drinking Water Supplies to Remove
MTBE?
Because spills of conventional gasoline typically move slowly
through groundwater, and are biodegraded over time, many are left in
place to undergo bioremediation at no cost other than temporarily
replacing the water supply. However, MTBE moves rapidly with
groundwater, is not readily degraded in the groundwater environment,
and can render groundwater unpotable at low levels. Therefore, spills
involving MTBE require much more aggressive management and remediation
than do spills of conventional gasoline.
MTBE's chemical properties also make it difficult or costly to
remediate using conventional ``active'' processes. Two common treatment
techniques are air stripping and use of granular activated carbon
(GAC). In air stripping, contaminated groundwater is passed through an
aeration tower that effectively removes the chemicals from the water
and releases it into the air. Where necessary, the chemical is then
removed from the air into a solid medium that can be disposed of. MTBE
does not readily partition from water to the vapor phase. Air stripping
of MTBE is most effective when higher air to water ratios, or higher
temperatures are used than would be required for other more volatile
compounds. In a GAC system, water is passed through one or more beds of
carbon; contaminants in the water are sorbed onto the carbon, which can
either be disposed of or ``refreshed'' by driving out the contaminants
(usually by heating). However, the relatively low sorption of MTBE to
solid particles means that the GAC must be used in greater quantities,
driving up treatment costs. As a practical matter, therefore, MTBE-
contaminated groundwater is difficult and costly to remediate.
F. What Action did EPA's Blue Ribbon Panel Recommend?
In November 1998, EPA established a the Panel to investigate air
quality benefits and water quality concerns associated with the use of
oxygenates, including MTBE, in gasoline. The Panel was established
under EPA's Clean Air Act Advisory Committee, a policy committee
established to advise EPA on issues related to implementing the CAA
Amendments of 1990.
The Panel members consisted of leading experts from the public
health, environmental and scientific communities, automotive and fuels
industry, water utilities, and local and State governments. The Panel
met six times from January to June 1999, with the charge to:
1. Examine the role of oxygenates in meeting the nation's goal of
clean air.
2. Evaluate each product's efficiency in providing clean air
benefits and the existence of alternatives.
3. Assess the behavior of oxygenates in the environment.
4. Review any known health effects.
5. Compare the cost of production and use and each product's
availability--both at present and in the future.
Further, the Panel studied the causes of groundwater and drinking
water contamination from motor vehicle fuels, and explored prevention
and cleanup technologies for water and soil. In September 1999, the
Panel released its report, entitled Achieving Clean Air and Clean
Water, The Report of the Blue Ribbon Panel on Oxygenates in Gasoline.
The Report is available in the docket to this ANPRM, and is also
available on http://www.epa.gov/oms/consumer/fuels/oxypanel.blueribb.htm.
The Panel recommended a package of reforms to ensure that water
supplies are better protected while the substantial reductions in air
pollution that have resulted from RFG are maintained. The Panel
enumerated 16 suggestions for Federal, State, and Congressional action,
including the following:
Recommended a comprehensive set of improvements to the
nation's water protection programs, including over 20 specific actions
to enhance UST, safe
[[Page 16103]]
drinking water, and private-well protection programs.
Agreed broadly that use of MTBE should be reduced
substantially (with some members supporting its complete phase out),
and recommended action by Congress to clarify Federal and State
authority to regulate and/or eliminate the use of MTBE and other
gasoline additives that threaten drinking water supplies.
Recommended that Congress act to remove the current CAA
requirement that 2% of RFG, by weight, consist of oxygen, to ensure
that adequate fuel supplies can be blended in a cost-effective manner
while quickly reducing usage of MTBE.
Recommended that EPA take action to ensure that there is
no loss of current air quality benefits associated with the use of
MTBE.
While the Panel indicated that its recommendations should be
implemented as a complete package, it also stated that ``the majority
of these recommendations could be implemented by Federal and State
environmental agencies without further legislative action, and we would
urge their rapid implementation.''
Although the Panel agreed broadly on its recommendations, two
members, while in general agreement with the Panel, had concerns with
specific provisions: The MTBE industry representative disagreed with
the recommendation to limit the use of MTBE, and the ethanol industry
representative disagreed with the recommendation that the CAA
requirement that oxygenates be used in RFG be eliminated. Some Panel
members believed that MTBE use should be banned altogether.
EPA agrees with the concerns raised in the report of the Panel
regarding the continued use of MTBE as a fuel additive, and will
consider its recommendations further as it proceeds through a TSCA
section 6 rulemaking to limit or ban MTBE's use in gasoline.
IV. Section 6 of the Toxic Substances Control Act
A. What is the Scope of TSCA Section 6 Authority?
Section 6 of TSCA, 15 U.S.C. 2605, provides EPA with broad
authority to issue rules to regulate the manufacture, processing,
distribution in commerce, use, and/or disposal of chemical substances
in the United States where such regulation is necessary to prevent
unreasonable risks to health or the environment. The Agency and courts
have interpreted the ``unreasonable risk'' standard to be a risk-
benefit standard, allowing regulation where risks to health or the
environment posed by a particular activity or activities involving a
chemical outweigh the benefits associated with such activity or
activities. TSCA section 6 lists a number of possible forms that such
regulation may take, including:
1. Regulating the manufacturing, processing, or distribution in
commerce of a chemical substance, including a complete ban of any such
activity or limiting the amounts of the chemical substances that may be
manufactured, processed, or distributed in commerce.
2. Regulating the manufacturing, processing, or distribution in
commerce of a chemical substance for a particular use or uses,
including banning any such activity for a particular use or uses of the
chemical substance; limiting the concentration of the chemical
substance that may be used in any such activity; or limiting the
amounts of the chemical substance that may be manufactured, processed,
or distributed in commerce for such particular use or uses.
3. Requiring that the chemical substance be accompanied by such
warning statements and/or instructions for use with respect to its use,
distribution in commerce, and/or disposal as the Administrator finds
necessary.
4. Requiring manufacturers and/or processors of a chemical
substance to make and retain such records of the manufacturing process
as the Administrator finds necessary and/or to monitor or conduct tests
which are reasonable and necessary to assure compliance with a rule
under TSCA section 6.
5. Prohibiting or regulating any manner or method of commercial use
of a chemical substance.
6. Prohibiting or regulating the disposal of a chemical substance.
7. Requiring manufacturers or processors of a chemical substance to
provide warnings to distributors or users of the substance and to
replace or repurchase such substance.
TSCA section 6(a) directs the Agency to apply the least burdensome
of the identified regulatory options to the extent necessary to
mitigate the unreasonable risk. The statute also makes clear that the
Agency may select a combination of the options, and may limit the
geographic application of a rule under TSCA section 6(a).
In promulgating any rule under TSCA section 6(a), TSCA section 6(c)
requires the Agency to publish a statement addressing:
1. The effect of the chemical substance being regulated on health
and the magnitude of exposure of humans to the substance.
2. The effects of such substance on the environment and the
magnitude of exposure of the environment to the substance.
3. The benefits of such substance for various uses and the
availability of substitutes for such uses.
4. The reasonably ascertainable economic consequences of the rule,
after consideration of the effect on the national economy, small
business, technological innovation, the environment, and public health.
TSCA section 6(c) also provides that if the Administrator
determines that the risk of injury to health or the environment could
be eliminated or reduced to a sufficient extent through actions taken
under another statute administered by EPA, she may not promulgate a
rule under TSCA section 6 unless the Administrator finds, in her
discretion, that it is in the public interest to protect against such
risk under TSCA. In making this finding, the Administrator must
consider all relevant aspects of the risk; a comparison of the
estimated costs of complying with actions taken under TSCA and any
other statute that adequately addresses the risk; and the relative
efficiency of actions under TSCA and such other statute to address the
risk.
Any rulemaking under TSCA section 6 includes the opportunity for
any interested person to request an informal hearing. Such hearings
could be limited to the right to present an oral statement, or could
include the right to present and cross-examine witnesses if the
Administrator determines that there are disputed issues of material
fact necessary to be resolved and that cross-examination of witnesses
is both appropriate and required for full and true disclosure with
respect to such issues.
B. How Would EPA Apply TSCA Section 6 to Risks Associated with MTBE?
As discussed earlier, the use of MTBE as an additive in gasoline
has resulted, and if unchanged is likely to continue to result, in the
widespread release of MTBE into the environment; MTBE is difficult to
contain and prevent from reaching sources of drinking water once it is
released into the environment; and it has the potential to render
drinking water unpotable at low levels and unsafe at higher levels.
EPA's review of existing information on contamination of drinking water
resources by MTBE indicates substantial evidence of a significant risk
to the nation's drinking water supply. A comprehensive
[[Page 16104]]
approach to such risk must include consideration of either reducing or
eliminating the use of MTBE as a gasoline additive. As a result, EPA is
initiating this process pursuant to the unreasonable risk provision
under TSCA section 6 to eliminate or greatly reduce the use of MTBE as
a gasoline additive. EPA is interested in comments on both the risk and
these possible responses to it. In accordance with the requirements of
TSCA section 6, EPA will consider whether there are other appropriate
mechanisms to address the problems presented by the use of MTBE as a
gasoline additive. Thus, the outcome of this rulemaking could be a
total ban on the use of MTBE as a gasoline additive. Consistent with
TSCA section 6, EPA will carefully consider regulatory alternatives to
a ban. These could include limiting the amount of MTBE that could be
used in gasoline, limiting use of MTBE in particular geographic areas
or during particular times of year; limiting the types of facilities in
which MTBE can be stored; limiting the manner in which MTBE is
transported; etc. Any final outcome must, however, provide adequate
protection against any unreasonable risk associated with MTBE.
As part of a rulemaking under TSCA section 6, the Agency must also
consider whether action under another statute administered by EPA, such
as the CAA, RCRA, CWA, or SDWA, could effectively address the risks
posed by MTBE and, if so, whether it is in the public interest to
regulate the risk under TSCA instead of such other statute. It is worth
noting in this regard that although a number of Agency programs could
address some of the risks posed by MTBE (such as, for example, the
regulation of USTs under RCRA), TSCA appears to provide the best tool
for assessing and addressing the risks posed by MTBE.
As part of the consideration of other programs and identification
of the least burdensome mechanism to provide adequate protection
against the risks of MTBE, the Agency expects to consider a number of
possible strategies for mitigating those risks, including preventing
MTBE in gasoline from getting into groundwater, cleaning up water
contaminated with MTBE, and removing MTBE from gasoline in whole or in
part. While the Agency's assessment in this regard is preliminary at
this point, the available evidence suggests that dealing with the
problem before MTBE is added to gasoline may be the best solution for
mitigating any unreasonable risks associated with MTBE. Given the large
quantities of gasoline that are used and transported in the United
States, and the number of different possible avenues for release into
the environment (including leaks from storage tanks and pipelines;
spills resulting from loading/unloading gasoline at tanks, gasoline
pumps, or pipelines; spills resulting from transportation accidents;
un-combusted gasoline from boat engines; emissions from automobile
exhaust), it may not be practicable to prevent significant quantities
of MTBE from getting into surface water or groundwater once the
chemical is added to gasoline. Similarly, given the importance of
groundwater as a drinking water source in the United States and the
large number of wells and groundwater sources that have been and could
be contaminated with MTBE and the costs and difficulties of cleaning
contaminated drinking water sources, a risk-mitigation strategy
centering on cleaning up water may not be the preferred strategy under
TSCA section 6 for mitigating any unreasonable risks associated with
MTBE. Consequently, EPA believes that a comprehensive approach must
include consideration of either reducing or eliminating the use of MTBE
as a gasoline additive.
In conducting this rulemaking under TSCA section 6, the Agency will
also consider the costs and impacts of alternatives to MTBE. In
oxygenated gasoline programs like Federal RFG, the most likely
substitute based on current usage is ethanol. Other ether compounds are
currently used as oxygenates in small quantities. MTBE does not occupy
as dominant a position as an octane enhancer for conventional gasoline
as it does as an oxygenate in RFG. Ethanol, alkylates, and aromatics
are alternative octane enhancers in conventional gasoline. Although EPA
is seeking more information on alternatives to MTBE, EPA does not
expect ethanol, alkylates, or aromatics to present the same magnitude
of risk to drinking water supplies as MTBE. Ethanol biodegrades more
quickly than MTBE, and therefore is less likely to contaminate drinking
water as often as MTBE, or at the levels of MTBE. Alkylates and
aromatics are expected to behave in soil and water more like other
components typically found in gasoline than MTBE; they too would be
unlikely to contaminate drinking water as often as MTBE or at the
levels of MTBE. Other ether compounds are not currently used widely as
oxygenates, and the Agency does not have much data to characterize the
risks they might pose to drinking water supplies. However, they are
chemically similar to MTBE, and they may well move through soil and
water in ways and amounts similar to MTBE. EPA will closely evaluate
the likelihood that compounds not currently used in significant
quantities as oxygenates in RFG might be widely used as alternatives to
MTBE, whether additional information on these compounds is necessary,
and whether other measures are appropriate to assure that an
elimination or limitation of MTBE in gasoline does not result in the
use of alternatives that might cause similar risks to drinking water.
It appears that eliminating or limiting the use of MTBE as a fuel
additive will result in increased costs in producing gasoline of
approximately $1.9 billion per year if the oxygen mandate remains in
place.
V. Alternative Gasoline Additives to MTBE
In conducting a rulemaking under TSCA section 6, EPA must consider
the alternatives to MTBE. If the use of MTBE as a fuel additive is
limited or banned by EPA, refiners will have to look to other chemicals
as substitutes. To meet the oxygenate requirements of RFG, ethanol and
other ethers are the most likely alternatives, while ethanol,
alkylates, and aromatics will most likely replace MTBE as an octane
enhancer. This unit assesses these chemicals and their potential to
replace MTBE in gasoline.
A. What Oxygenates Other Than MTBE Could be Used to Meet RFG
Requirements?
If the use of MTBE is limited or banned and the CAA oxygenate
requirement remains in place, refiners will have to use a substitute
oxygenate to meet the RFG requirements. Ethanol and other ethers are
the most likely oxygenate alternatives.
1. Ethanol. Ethanol is an oxygenate that is produced from
agricultural products such as corn. Ethanol and MTBE have been the
primary oxygenates used to meet the RFG oxygen content requirements
because of their availability, blendability, and ability to deliver air
quality benefits. Ethanol is currently the primary oxygenate in about
12.5% of RFG, and it is the main oxygenate in the Midwest RFG areas.
Despite its current use in RFG, ethanol is not yet manufactured in
sufficient volume to meet total current national oxygenate demands.
Current U.S. ethanol production capacity is estimated at 120,000 b/d
(barrels per day), which is equivalent in oxygen content to
approximately 230,000 b/d of MTBE. In order for ethanol alone to
fulfill the nationwide oxygen requirement in all RFG and oxygenated
[[Page 16105]]
fuels areas, the Panel estimated that at least an additional 67,000 b/d
of ethanol would be needed. Because of the higher oxygen content of
ethanol, a smaller volume of ethanol (5.7%) needs to be added to a
gallon of RFG to satisfy the CAA oxygen content requirement than MTBE
(11% by volume).
This shortfall in ethanol supply could be fulfilled by a
combination of increasing production capacity at existing facilities
and by building new facilities. The ethanol industry estimates that the
current expansion of existing ethanol-from-corn production facilities
may increase production capacity by as much as 40,000 b/d. (Ref. 36)
Additionally, the industry estimates that new ethanol production
facilities currently being planned could provide another 25,000 b/d.
Ethanol production from biomass processing is currently approximately
4,000 b/d. Thus, while there is an insufficient supply of ethanol to
meet current oxygenate demand, the ethanol industry projects that
future ethanol production should be able to adequately meet the
oxygenate demand and replace MTBE given appropriate time. The
Department of Agriculture (USDA) has concluded that ethanol can fully
meet all oxygenate requirements within 4 years. (Ref. 37)
Refiners that currently use MTBE in meeting the oxygenate
requirement would need to modify their operations to produce an
appropriate blendstock to which ethanol can be added. Terminals,
responsible for actually adding the ethanol to the gasoline, would also
have to modify their facilities. For example, terminals would have to
add storage facilities for ethanol. Due to these initial logistical
concerns, refiners have stated that an immediate ban on MTBE could have
a negative impact on the nation's fuel supply.
In addition to initial capital costs, use of ethanol as a
replacement for MTBE would have several long term impacts on the price
of gasoline. When added to gasoline, ethanol increases the Reid Vapor
Pressure (RVP) of the gasoline by about 1.0 pound per square inch. RVP
is a measure of the gasoline's volatility. An RVP increase results in
an increase in emissions of VOCs from motor vehicles. To compensate for
this increase, and to reduce the risk of VOCs evaporating into the air,
refiners must blend ethanol gasoline with a low-RVP blendstock. This
low-RVP blendstock is more expensive to produce or purchase.
In order to make RFG with MTBE, refiners blend MTBE into gasoline.
After mixture, the RFG is transported to distribution terminals by
pipeline. Since ethanol is soluble in water, which is commonly found in
pipelines, and will separate from gasoline, ethanol is usually blended
at the distribution terminal. Because ethanol is produced primarily in
the Midwest, though, it must be transported to terminals by either an
ethanol-only pipeline, rail, marine or truck shipping or some
combination of these options. It is possible that greater
transportation connections between ethanol producers and terminals will
have to be developed. The USDA study indicates that given a 3 to 5 year
transition period, there does not appear to be a transportation
impediment to the use of ethanol as a substitute for MTBE. (Ref. 38)
Economic impacts are not likely to be shared equally among
petroleum refiners/marketers. Each refinery processes different types
of crude, supplies different mixes of products (e.g., some refineries
do not manufacture any RFG), and use widely varying technologies. Areas
of the country that rely heavily on MTBE as an oxygenate will
experience a more pronounced economic effect in the event of an
oxygenate replacement or removal (e.g., Texas, California, and
Northeast RFG markets use MTBE, whereas the Chicago and Milwaukee RFG
markets use ethanol). In addition, markets farthest from the Midwest
may experience a greater effect due to increased transportation costs.
The economic impact of using ethanol as an alternative to MTBE will
be reflected primarily in the price of gasoline. A 1999 study by the
DOE concluded that a phased elimination of MTBE as an additive for
oxygenation in RFG in 4 years would result in an increase in the price
of RFG of between 2.4 cents per gallon and 3.9 cents per gallon. (Ref.
39) A California Energy Commission (CEC) study estimated that the price
of gasoline in California would increase anywhere from 1.9 cents per
gallon to 2.5 cents per gallon in the long term (6 years) if ethanol
was substituted for MTBE. (Ref. 40) A Chevron/Tosco analysis estimated
that gasoline prices in California would increase 1.9 cents per gallon
in the long term (6 years) if ethanol was substituted for MTBE. (Ref.
41)
Pure ethanol is highly soluble in water, and hypothetically should
travel in groundwater at about the same rate as MTBE. Ethanol is not
expected to persist in groundwater, though, because it biodegrades
easily. Thus, ethanol itself does not appear to pose as great a danger
to groundwater supplies as MTBE.
Ethanol's ability to biodegrade does present another potential
issue of concern. Laboratory data and hypothetical modeling indicate
that based on physical, chemical, and biological properties, ethanol
will likely preferentially biodegrade in groundwater compared with
other gasoline components. As a result, the levels of BTEX in water may
decline more slowly, and BTEX plumes may extend further than they would
without ethanol present. However, BTEX does not migrate as quickly as
MTBE. Thus, even with the presence of ethanol, BTEX plumes would not be
expected to travel as far as MTBE plumes. Although there are limited
data regarding the movement of ethanol and BTEX, a recent USGS report
cites several examples of MTBE plumes migrating further than BTEX
plumes. (Ref. 42) At some sites, MTBE has migrated much further than
other common gasoline components and those long travel distances
increase the probability that MTBE will be detected in a drinking water
well and that treatment may be required.
The health effects of ingested ethanol have been extensively
investigated. Given that ethanol is formed naturally in the body at low
levels, inhalation exposure to ethanol at the low levels that human are
likely to be exposed are generally not expected to result in adverse
health effects. (Ref. 43) Ingestion of ethanol in relatively large
quantities, increases the risks for several forms of human cancer.
(Ref. 44) However, it is highly unlikely that the public will be
exposed to large quantities of ethanol from drinking water
contamination.
When used as an oxygenate, ethanol blends of RFG achieve all Phase
I goals of the RFG program. Ethanol is the primary oxygenate in Chicago
and Milwaukee, and those areas have easily exceeded all Phase I
performance requirements for VOCs, NOX and air toxics. Thus,
use of ethanol as an oxygenate nationwide would not appear to
compromise compliance with air quality requirements; refiners seem able
to produce RFG using ethanol that complies with RFG emissions
standards. The Panel did note, however, that Chicago and Milwaukee,
while exceeding the Phase I requirements, do not appear to achieve as
great a reduction in air toxics as do other RFG areas. It is unclear
whether MTBE is responsible for this greater reduction in air toxics or
other aspects of the formulation. Starting in the year 2000, all RFG
areas will be subject to more stringent standards for VOC,
NOX and toxics reductions, regardless of which oxygenate is
used.
2. Other ethers. A variety of other ethers (ETBE, DIPE, TAME) are
[[Page 16106]]
currently used in gasoline, though in limited quantities; these ethers
provide approximately 5% of the oxygenate used in RFG. These other
ethers have found only limited use because they are more expensive than
MTBE. For example, greater volumes of ETBE and TAME are necessary to
achieve the 2.0% weight standard compared to MTBE. Use of ETBE also
requires large quantities of ethanol as feedstock. Production supplies
of other ethers are also limited. The current production capacity in
this country of TAME is approximately 23,000 b/d. Increasing ETBE
production would require refitting MTBE plants, primarily in the Gulf
South. Transportation issues could be similar to those involving
increased use of ethanol. CEC estimates that gasoline prices will
increase 2.4 cents per gallon if ETBE is used to replace MTBE. (Ref.
45) This estimate is specific to California.
Given their similarity to MTBE, other ethers are likely to display
similar chemical properties--high solubility in groundwater, poor
sorption in soil, and slower biodegradation compared to BTEX. MTBE has
become a concern in large part because of its chemical properties. MTBE
can travel farther than other gasoline constituents and can create
larger contamination plumes, making it more likely to impact drinking
water supplies. Other ethers are likely to demonstrate the same
properties and thus could well raise similar water contamination
concerns as MTBE. No studies have been reported on the carcinogenicity
of ETBE, TAME, or TBA.
B. What Compounds Other Than MTBE Could be Added to Gasoline to Boost
Octane?
In addition to its use as an oxygenate, MTBE is also used as an
octane enhancer in conventional gasoline. However, while MTBE is the
dominant oxygenate additive in RFG, it is not the predominant octane
enhancing additive in conventional gasoline. More conventional gasoline
contains ethanol as an octane enhancer than contains MTBE for that
purpose. In 1997, approximately 12,000 b/d of MTBE were used for octane
enhancement purposes. If MTBE is banned or its use as an octane
enhancer is limited, refineries will have to look to other alternatives
to replace this source of octane. There are a limited number of octane-
rich components that refiners can choose to produce needed octane.
Ethanol, alkylates, and aromatics are the three most likely available
alternatives to MTBE for use as an octane enhancer in conventional
gasoline. Ethanol as an additive is discussed in Unit V.A.1.
1. Alkylates. Alkylates are a mix of high octane, low vapor
pressure compounds that are produced from crude oil through a catalytic
cracking process. Because of their desirable properties, alkylates are
popular components for use in gasoline.
In order for a refiner to use alkylates as an octane enhancer, the
refiner must possess an alkylation unit. According to an industry
estimate, an alkylation unit can cost up to $80 million for a refinery
that produces 10,000 b/d of alkylate. (Ref. 46) Refiners that do not
currently use alkylates would have to make a substantial initial
capital investment in order to do so. In addition, refiners would need
to adjust other component streams to accommodate the change in vapor
pressure characteristics associated with a fuel containing high
alkylate content.
Supply of alkylates could be a key economic consideration. There
are currently not enough domestic alkylates available to make up for
the loss in MTBE volume. While increasing alkylate production is
possible, it appears that refiners in California have limited
possibilities for such an increase. Alkylate production on the East
Coast and Gulf Coast also appears to be close to capacity. Given this
situation, it may take refiners some number of years to modify
facilities to produce enough alkylates to replace the octane
enhancement currently provided by MTBE.
It is unclear, however, how much alkylate is needed to replace MTBE
as an octane enhancer. Only 12,000 b/d of MTBE are currently used for
octane enhancement in conventional gasoline. MTBE has a higher octane
value than alkylates, and a simple linear comparison of these values
would conclude that 14,350 b/d of alkylates would be necessary to
replace MTBE. This linear comparison would not take into account
several factors important in determining the amount of alkylates used,
such as the blend of gasoline. Refineries can be expected to react in
different ways to these factors to maximize production and economic
feasibility and to meet performance standards.
Alkylates are less soluble in water, and they will not likely pose
the same degree of risks to water resources as MTBE. Alkylates would be
expected to behave more like other components of gasoline (BTEX) than
like MTBE if released into the environment. Alkylates thus do not
appear to pose a significant threat to drinking water resources.
According to NESCAUM, increased use of alkylates in gasoline blends
will not increase toxic emissions. (Ref. 47) However, the available
human and aquatic toxicity data on alkylates are limited.
2. Aromatics. Aromatics are hydrocarbons which can include benzene,
toluene, and xylene. Toluene is the primary aromatic used for octane
enhancing. NESCAUM estimates that current toluene production capacity
may be sufficient to produce enough toluene to replace MTBE by volume.
(Ref. 48) The aromatics are significantly less likely to end up in
drinking water sources in significant quantities after release to the
environment than is MTBE.
Aromatics contain compounds that are known to have a range of
potential human health effects. Benzene is a known human carcinogen,
and xylene is a major contributor to smog. Toluene is associated with
some toxic by-products, though it is less toxic than benzene.
VI. Specific Requests for Comment, Data, and Information
Interested persons are invited to comment on any issue raised in
this ANPRM. The Agency is particularly interested in receiving
additional information and/or comments addressing the following issues:
A. EPA Action
As explained in this ANPRM, EPA is initiating this process pursuant
to TSCA section 6 to consider eliminating or limiting the use of MTBE
in gasoline. EPA requests comment (including comments addressing the
health, environmental, and/or cost implications) on:
1. Whether some use of MTBE as a gasoline additive should be
allowed to continue and, if so, the level or type of use that should be
allowed to continue?
2. How much lead time, if any, would be necessary to enable
refiners to eliminate MTBE from RFG while continuing to meet the
current levels of compliance with RFG standards for VOC,
NOX, and toxic emissions without unacceptable impacts on the
price or supply of fuel?
3. How much lead time, if any, would be necessary to enable
refiners to eliminate MTBE as an octane enhancer in conventional
gasoline without unacceptable impacts on the price or supply of fuel?
4. Whether EPA should obtain additional information on, or reduce,
eliminate, or cap the use of any other gasoline additives in addition
to MTBE?
5. Whether MTBE presents significantly greater risk to public
health
[[Page 16107]]
and/or water quality than alternative gasoline additives.
B. Releases of Gasoline Containing MTBE, Contamination of Water
Resource by MTBE, and Remediation Technologies
1. As explained in this ANPRM, the Agency identified numerous and
widespread instances of MTBE contamination of groundwater. In order to
ensure that EPA has the most recent and accurate data available, EPA
requests information regarding incidents of both releases of gasoline
containing MTBE and the detection of MTBE in groundwater, surface
waters, or drinking water supplies. Comments should include, to the
extent possible, the amounts, locations, sources, and types of MTBE
releases, and the levels and sources of water resource contamination
from MTBE.
2. EPA is interested in additional information concerning the
toxicity of MTBE, the levels at which its taste or odor can be detected
in water, the levels at which its taste or odor makes water
unacceptable to consumers, and any other properties of MTBE that may be
relevant to a rulemaking under TSCA section 6.
3. EPA's summary of current MTBE contamination problems suggests
that there is significant risk of additional future contamination of
water resources by MTBE from gasoline. In order to more comprehensively
characterize this risk EPA is requesting comment regarding the likely
future occurrence of MTBE contamination in groundwater, surface water,
and/or drinking water.
4. EPA is requesting information regarding the relative
contribution of different sources (such as USTs, spills, storm water
runoff, air deposition, and marine engines) to present and future MTBE
contamination of groundwater, surface water, and drinking water.
5. EPA is requesting information regarding the cost and efficacy of
technologies for remediating soil and drinking water sources that have
been contaminated with MTBE. EPA is particularly interested in examples
of remediation efforts that have addressed MTBE contamination, and cost
and efficacy comparisons with remediation efforts for other components
of gasoline (such as BTEX).
C. Alternatives to MTBE
1. EPA is requesting information on potential substitutes,
including those not identified in this ANPRM, that might replace MTBE
either as an oxygenate in RFG or an octane enhancer in conventional
gasoline. In addition to identifying a potential substitute, any
information addressing the following would be helpful:
a. The basis for the belief that the substitute might replace MTBE
in significant quantities.
b. The behavior of the substitute in soil and water, with an
emphasis on the quantities of the substitute that might find their way
into drinking water sources if the substitute is added to gasoline.
c. Toxicity, taste or odor properties, current exposure levels, or
any other properties or considerations of the substitute that may be
relevant to a rulemaking under TSCA section 6.
2. EPA is interested in information based on actual releases of
oxygenates and other gasoline additives other than MTBE to the
environment; including degree of contamination, the spread of any
contaminant plumes, and the cost and efficacy of the technologies
available to remediate such contamination. Comments should include, to
the extent possible, the amounts, locations, sources and types of
releases, and the levels and sources of water resource contamination
from these oxygenates and additives, as well as from other gasoline
constitutents.
3. EPA is interested in information regarding any possible impacts
on health or the environment that might result from the elimination or
limitation of use of MTBE as a gasoline additive and the use of
alternative compounds in MTBE's place, including not only whether
alternative additives may have a greater or lesser impact than MTBE on
drinking water sources, but also whether increased use of such
alternatives might have other beneficial or negative consequences on
human health or the environment (such as air quality or water quality
impacts).
D. Economic Considerations
1. EPA is requesting comment on the cost impacts of an elimination
or limitation of MTBE in gasoline, in the absence of a change in the
RFG requirements. EPA is particularly interested in comments that
address:
a. The cost implications of an immediate elimination of MTBE from
gasoline nationwide.
b. The cost implications of an immediate nationwide limit on MTBE
content in gasoline to pre-RFG levels or levels generally associated
with the use of MTBE for purposes of octane enhancement.
c. The cost implications of a phase out of MTBE from gasoline
nationwide, resulting in complete elimination in a period of 3 to 4
years or 5 to 6 years.
d. The cost implications of a nationwide phase down of MTBE content
in gasoline, over 3 to 4 years, resulting in a limit on MTBE content
equivalent to pre-RFG levels or levels generally associated with the
use of MTBE for purposes of octane enhancement.
2. EPA is requesting comment regarding any information that was not
considered by the Blue Ribbon Panel on the availability of alternative
oxygenates and octane enhancers, the time it would take for production
of alternatives to meet national demand, and the potential impacts on
fuel supply and price.
VII. References
1. Moran, Michael J., Zogorski, John S., and Squillance, Paul J.
USGS. MTBE in Ground Water of the United States--Occurrence, Potential
Sources, and Long Range Transport. Published in Proceedings of the 1999
Water Resources Conference. American Water Works Association.
2. USEPA, Office of Water. Drinking Water Advisory: Consumer
Acceptability Advice and Health Effects Analysis on Methyl Tertiary-
Butyl Ether (MTBE). December 1997.
3. Schirmer, Barker, J.F., Butler, B.J., Church, C.D., and
Schirmer, K., 1998, Natural Attenuation of MTBE at the Bordon field
site: in Wickramanayake, G.B., and Hinchee, R.E., Eds. Natural
Attenuation: Chlorinated and Recalcitrant Compounds: The First
International Conference on Remediation of Chlorinated and Recalcitrant
Compounds. Monterey, California. May 18-21, Battelle Press. Columbus,
OH. pp. 327-331.
4. Borden, R.C., Daniel, R.A., LeBrun, L.E. IV, and Davis, C.W.
Intrinsic biodegradation of MTBE and BTEX in a gasoline-contaminated
aquifer: Water Resources Research. Vol. 33. No. 5. pp. 1105-1115. 1997.
5. Alvarez, Pedro, et al. Health and Environmental Assessment of
the Use of Ethanol as a Fuel Oxygenate. Potential Ground and Surface
Water Impacts, The Effect of Ethanol on BTEX Biodegradation and Natural
Attentuation. Vol. 4. pp. 3-12. December 1999.
6. U.S. Energy Information Administration. Petroleum Supply Annual
1998. Vol. 1. Table S4. p. 17. June 1999.
7. U.S. Energy Information Administration (T. Litterdale and A.
Bohn). Demand and Price Outlook for Phase 2 Reformulated Gasoline,
2000. pp. 7-8. April 1999.
8. Prah, J.D., et al. Sensory, Symptomatic, Inflammatory, and
Ocular Responses to and the Metabolism of Methyl Tertiary Butyl Ether
in a Controlled Human Exposure
[[Page 16108]]
Experiment. Inhalation Toxicology. 6:521-528.
9. API. Odor Threshold Studies Performed with Gasoline and Gasoline
combined with MTBE, ETBE, and TAME. Washington DC. API #4592. 1993.
10. Oxygenated Fuels Association. Technical Memorandum: Taste and
Odor Properties of Methyl Tertiary Butyl Ether and Implications for
Setting a Secondary Maximum Contaminant Level. Prepared by Malcolm
Pirnie. 1998.
11. CENR. 1997 Interagency Assessment of Oxygenated Fuels.
Committee on the Environment and Natural Resources (CENR), Office of
Science and Technology Policy (OSTP), National Science and Technology
Center, (NSTC). June 1997.
12. USEPA, Office of Research and Development. 1994 Health Risk
Perspectives on Fuel Oxygenates. Report EPA/600R-94/217.
13. International Agency for Research on Cancer
Monographs.Evaluation of Methyl Tertiary Butyl Ether. Vol. 73. p. 339.
1999
14. National Institute of Environmental Health Sciences, National
Toxicology Program. Summary of RG1, RG2, and NTP Board Subcommittee
Recommendations for the Report on Carcinogens. Ninth Edition.1998.
15. Office of Science and Technology Policy, National Science and
Technology Council. Interagency Assessment of Oxygenated Fuels. June
1997.
16. National Research Council (NRC). Toxicological and Performance
Aspects of Oxygenated Motor Vehicle Fuels. June 1996.
17. The Alliance for Proper Gasoline Handling. http://www.gas-care.org. New Alliance Launches Consumer ``Gas Care'' Campaign to
Prevent Small Gasoline Spills. Press Release dated, July 27, 1999.
18. Hunter, B., et al. Impact of Small Gasoline Spills on
Groundwater, preliminary report abstract presented at the Maine Water
Conference Meeting, April 1999, and NESCAUM, RFG/MTBE Findings and
Recommendations. Boston, MA. August 1999.
19. NESCAUM, RFG/MTBE Findings and Recommendations. Boston, MA. p.
4. August 1999.
20. NESCAUM, RFG/MTBE Findings and Recommendations. Boston, MA.
August 1999.
21. Reuter, J. E., et al. Concentrations, Sources and Fate of the
Gasoline Oxygenate Methyl Ter-Butyl Ether (MTBE) in a Multiple-Use
Lake. Environmental Science and Technology. 32, 3666-3672. 1998.
22. Squillance, Paul, et al. A Preliminary Assessment of the
Occurrence and Possible Sources of MTBE in Ground Water of the United
States, 1993-1994. Environmental Science and Technology. Vol. 30. No.
5. pp. 1721-1730. 1996.
23. Zogorski, John, et al. MTBE Summary of Findings and Research by
the U.S. Geological Survey. Proceedings of the 1998 Annual Conference
of the American Water Works Association.
24. Moran, Michael J., Zogorski, John S., and Squillance, Paul J.
USGS. MTBE in Ground Water of the United States--Occurrence, Potential
Sources, and Long Range Transport. Published in Proceedings of the 1999
Water Resources Conference. American Water Works Association.
25. Squillace, Paul, USGS. MTBE in the Nation's Ground Water,
National Water--Quality Assessment (NAWQA) Program Results,
Presentation Before the Blue Ribbon Panel on Oxygenates in Gasoline.
April 29, 1999.
26. USGS/USEPA Joint Study. Preliminary Findings of the 12-State
MTBE Drinking Water Retrospective.
27. State of Maine Bureau of Health, Department of Human Services,
Bureau of Waste Management & Remediation, Department of Environmental
Protection, Maine Geological Survey, and the Department of
Conservation. Maine MTBE Drinking Water Study, The Presence of MTBE and
other Gasoline Compounds in Maine's Drinking Water--Preliminary Report.
1998.
28. Siddiqui, Mohamed, et al. Occurrence of Perchlorate and Methyl
Tertiary Butyl Ether (MTBE) in Ground Water of the American Water
System. American Water Works Service Company Inc. September 30, 1998.
29. Buscheck, T. E., Gallagher, D. J., Kuehne, D. L., Zuspan, C. R.
Occurrence and Behavior of MTBE in Groundwater. Presented at:
Underground Storage Tank Conference: '98 & Beyond. Los Angeles, CA.
Sacramento, CA. State of California Water Resources Control Board.
April 1998.
30. Hitzig, Robert, et al. Study Reports LUST Programs Are Feeling
Effects of MTBE Releases. Soil and Ground Water Clean-Up. pp. 15-19.
August-September 1998.
31. Robbins, G.A., Henebry, B.J., Schmitt, B.M., Bartolomeo, F.B.,
Green, A., and Zack, P. Evidence for MTBE in Heating Oil. Groundwater
Monitoring and Remediation. Vol. 19. No.2. pp.65-69. 1999.
32. U.S. Energy Information Administration. Petroleum Supply Annual
1998. Vol. 1. Table S4. p. 17. June 1999.
33. The Report of the Blue Ribbon Panel on Oxygenates in Gasoline.
Achieving Clean Air and Clean Water.
34. Delzer, G.C., Zogorski, J.S., Lopes, T.J., and Bosshart, R.L.
Occurrence of Gasoline Oxygenate MTBE and BTEX Compounds in Urban
Stormwater in the United States, 1991-1995. USGS Water-Resources
Investigations Report. 96-4145. 1996.
35. Office of Science and Technology Policy, National Science and
Technology Council. Interagency Assessment of Oxygenated Fuels. June
1997.
36. Huggins, Jack. Submitted written comments on behalf of the
Renewable Fuels Association at the April 1999 Meeting of the Blue
Ribbon Panel on Oxygenates in Gasoline.
37. Letter from Agriculture Secretary Dan Glickman to Senator Tom
Harkin, dated November 15, 1999. Attached Analysis entitled ``Economic
Analysis of Replacing MTBE with Ethanol in the United States.''
38. USDA. Economic Analysis of Replacing MTBE with Ethanol in the
United States. November 1999.
39. DOE. Estimating the Refining Impacts of Revised Oxygenate
Requirements for Gasoline: Follow-up Findings. May 1999.
40. California Energy Commission. Supply and Cost Alternatives to
MTBE in Gasoline. October 1998.
41. MathPro. Potential Economic Benefits of the Feinstein-Bilbray
Bill. March 18, 1999.
42. Moran, Michael J., Zogorski, John S., and Squillance, Paul J.
USGS. MTBE in Ground Water of the United States Occurrence, Potential
Sources, and Long Range Transport, Published in Proceedings of the 1999
Water Resources Conference. American Water Works Association.
43. Blue Ribbon Panel. Achieving Clean Air and Clean Water. The
Report of the Blue Ribbon Panel on Oxygenates in Gasoline. p. 85.
September 1999.
44. Office of Science and Technology Policy, National Science and
Technology Council. Interagency Assessment of Oxygenated Fuels. June
1997.
45. California Energy Commission. Supply and Cost Alternatives to
MTBE in Gasoline. October 1998.
46. Estimate provided by industry representative via personal
communication Sheldon Thompson, Senior Vice President and Chief
Administrative Officer, Sunoco, Inc. via telephone communication and
inquiry. February 2000.
[[Page 16109]]
47. NESCAUM, RFG/MTBE Findings and Recommendations. Boston, MA.
August 1999.
48. NESCAUM, RFG/MTBE Findings and Recommendations. Boston, MA.
August 1999.
VIII. Regulatory Assessment Requirements
A. Executive Order 12866
Under Executive Order 12866 (58 FR 51735, October 4, 1993), the EPA
must determine whether a regulatory action is ``significant'' and
therefore subject to Office of Management and Budget (OMB) review and
the requirements of the Executive Order. The Executive Order defines
``significant regulatory action'' as one that is likely to result in a
rule that may:
1. Have an annual effect on the economy of $100 million or more, or
adversely affects in a material way the economy, a sector of the
economy, productivity, competition, jobs, the environment, public
health or safety, or State, local, or tribal governments or
communities;
2. Creates a serious inconsistency or otherwise interferes with an
action taken or planned by another agency;
3. Materially alters the budgetary impact of entitlements, grants,
user fees, or loan programs or the rights and obligations of recipients
thereof; or
4. Raises novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in
the Executive Order.
A draft of this ANPRM was reviewed by OMB prior to publication, as
required by E.O. 12866. Any changes made in response to OMB suggestions
or recommendations will be documented in the public record.
B. Federalism
Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August
10, 1999), requires EPA to develop an accountable process to ensure
``meaningful and timely input by State and local officials in the
development of regulatory policies that have federalism implications.''
``Policies that have federalism implications'' is defined in the
Executive Order to include regulations that have ``substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government.'' Under
Executive Order 13132, EPA may not issue a regulation that has
federalism implications, that imposes substantial direct compliance
costs, and that is not required by statute, unless the Federal
government provides the funds necessary to pay the direct compliance
costs incurred by State and local governments, or EPA consults with
State and local officials early in the process of developing the
proposed regulation. The EPA also may not issue a regulation that has
federalism implications and that preempts State law unless the EPA
consults with State and local officials early in the process of
developing the proposed regulation.
If EPA complies by consulting, Executive Order 13132 requires EPA
to provide to OMB, in a separately identified unit of the preamble to
the rule, a federalism summary impact statement. The federalism summary
impact statement must include a description of the extent of EPA's
prior consultation with State and local officials, a summary of the
nature of their concerns and the EPA's position supporting the need to
issue the regulation, and a statement of the extent to which the
concerns of State and local officials have been met. Also, when EPA
transmits a draft final rule with federalism implications to OMB for
review pursuant to Executive Order 12866, EPA must include a
certification from the agency's Federalism Official stating that EPA
has met the requirements of Executive Order 13132 in a meaningful and
timely manner.
EPA has determined that the requirements of Executive Order 13132
do not apply to this ANPRM, and therefore the Executive Order does not
apply to this ANPRM.
C. Small Business Concerns
Section 603 of the Regulatory Flexibility Act (RFA), 5 U.S.C. 601
et seq., as amended by the Small Business Regulatory Enforcement
Fairness Act (SBREFA) of 1996, Public Law 104-121, requires the
Administrator to assess the economic impact of proposed rules on small
entities, including small businesses. The Agency accordingly requests
comment on the potential economic impact on small business of the
limitation or elimination of MTBE as an oxygenate or octane enhancer in
gasoline. EPA does not anticipate, at this point, that the potential
action discussed in this ANPRM will have a significant economic impact
on small business. Comments on the potential economic impact of such an
action on small businesses will help the Agency meet its obligations
under the RFA, as amended by SBREFA, and will provide information to
assist the Agency in its efforts to minimize any significant economic
impact of such an action for potentially affected small businesses.
D. Children's Health Protection
Executive Order 13045, entitled ``Protection of Children from
Environmental Health Risks and Safety Risks'' (62 FR 19885, April 23,
1997) applies to any rule that:
1. Is determined to be ``economically significant'' as defined
under E.O. 12866.
2. Concerns an environmental health or safety risk that EPA has
reason to believe may have a disproportionate effect on children.
If the regulatory action meets both criteria, the Agency must
evaluate the environmental health or safety effects of the planned rule
on children, and explain why the planned regulation is preferable to
other potentially effective and reasonably feasible alternatives
considered by the Agency.
While E.O. 13045 does not require EPA to evaluate the health or
safety risks of actions discussed in an ANPRM, the Agency is,
nonetheless, soliciting comment on such risks. The potential action
discussed in this ANPRM might involve issues related to health or
safety risks. To the extent that this is the case, the potential action
would be intended to minimize or eliminate any such risks for all
people who utilize groundwater resources, including children. We
request comment on whether there are health or safety considerations
related to the potential action discussed in this ANPRM that may
disproportionately affect children.
List of Subjects in 40 CFR Part 755
Environmental protection, Air pollution, Fuel additives, Hazardous
substances, Water resources.
Dated: March 20, 2000.
Carol M. Browner,
Administrator.
[FR Doc. 00-7323 Filed 3-21-00; 2:11 pm]
BILLING CODE 6560-50-F