[Federal Register Volume 72, Number 103 (Wednesday, May 30, 2007)]
[Rules and Regulations]
[Pages 30142-30167]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-9707]
[[Page 30141]]
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Part III
Environmental Protection Agency
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40 CFR Part 82
Protection of Stratospheric Ozone: Listing of Substitutes for Ozone-
Depleting Substances-n-Propyl Bromide in Solvent Cleaning; Protection
of Stratospheric Ozone: Listing of Substitutes for Ozone-
DepletingSubstances-n-Propyl Bromide in Adhesives, Coatings, and
Aerosols; Final Rule and Proposed Rule
Federal Register / Vol. 72, No. 103 / Wednesday, May 30, 2007 / Rules
and Regulations
[[Page 30142]]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 82
[EPA-HQ-OAR-2002-0064; FRL-8316-8]
RIN 2060-AO10
Protection of Stratospheric Ozone: Listing of Substitutes for
Ozone-Depleting Substances-n-Propyl Bromide in Solvent Cleaning
AGENCY: Environmental Protection Agency.
ACTION: Final Rule.
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SUMMARY: The Environmental Protection Agency (EPA) determines that n-
propyl bromide (nPB) is an acceptable substitute for methyl chloroform
and chlorofluorocarbon (CFC)-113 in the solvent cleaning sector under
the Significant New Alternatives Policy (SNAP) program under section
612 of the Clean Air Act. The SNAP program reviews alternatives to
Class I and Class II ozone depleting substances and approves use of
alternatives which do not present a substantially greater risk to
public health and the environment than the substance they replace or
than other available substitutes.
DATES: This final rule is effective on July 30, 2007.
ADDRESSES: EPA has established a docket for this action under Docket ID
No. EPA-HQ-OAR-2002-0064. All documents in the docket are listed on the
http://www.regulations.gov Web site. Although listed in the index, some
information is not publicly available, i.e., Confidential Business
Information (CBI) or other information whose disclosure is restricted
by statute. Certain other material, such as copyrighted material, is
not placed on the Internet and will be publicly available only in hard
copy form. Publicly available docket materials are available either
electronically in http://www.regulations.gov or in hard copy at the Air
and Radiation Docket, EPA/DC, EPA West, Room 3334, 1301 Constitution
Ave., NW., Washington, DC. This docket facility is open from 8:30 a.m.
to 4:30 p.m., Monday through Friday, excluding legal holidays. The
telephone number for the Public Reading Room is (202) 566-1744, and the
telephone number for the Air and Radiation Docket is (202) 566-1742.
FOR FURTHER INFORMATION CONTACT: Margaret Sheppard, Stratospheric
Protection Division, Office of Atmospheric Programs, Mail Code 6205J,
Environmental Protection Agency, 1200 Pennsylvania Ave., NW.,
Washington, DC 20460; telephone number (202) 343-9163; fax number (202)
343-2362, e-mail address: [email protected]. Notices and
rulemakings under the SNAP program are available on EPA's Stratospheric
Ozone World Wide Web site at http://www.epa.gov/ozone/snap/regs.
SUPPLEMENTARY INFORMATION: Table of Contents: This action is divided
into eight sections:
I. General Information
A. Does this action apply to me?
B. What is n-propyl bromide?
C. What acronyms and abbreviations are used in the preamble?
II. How does the Significant New Alternatives Policy (SNAP) Program
work?
A. What are the statutory requirements and authority for the
SNAP Program?
B. How do the regulations for the SNAP Program work?
C. How does the SNAP Program list our decisions?
D. Where can I get additional information about the SNAP
Program?
III. What is EPA's final listing decision on nPB in solvent
cleaning?
IV. What criteria did EPA use in making this Final Decision?
A. Availability of alternatives to ozone-depleting substances
B. Impacts on the Atmosphere and Local Air Quality
C. Ecosystem and Other Environmental Impacts
D. Flammability and Fire Safety
E. Impact on Human Health
V. How is EPA responding to comments on the June 2003 Notice of
Proposed Rulemaking?
A. EPA's Acceptability Decision
B. Toxicity
C. Ozone Depletion Potential
D. Other Environmental Impacts
E. Flammability
F. Legal Authority to Set Exposure Limits
VI. How can I use nPB as safely as possible?
VII. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review
B. Paperwork Reduction Act
C. Regulatory Flexibility Act
D. Unfunded Mandates Reform Act
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination with
Indian Tribal Governments
G. Executive Order 13045: Protection of Children from
Environmental Health and Safety Risks
H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
I. National Technology Transfer and Advancement Act
J. Congressional Review Act
VIII. References
I. General Information
A. Does this action apply to me?
This final rule lists n-propyl bromide (nPB) as an acceptable
substitute when used as a solvent in industrial equipment for metals
cleaning, electronics cleaning, or precision cleaning. General metals,
precision, and electronics cleaning includes cleaning with industrial
cleaning equipment such as vapor degreasers, in-line cleaning systems,
or automated equipment used for cleaning below the boiling point. We
understand that nPB is used primarily for cleaning in vapor degreasers.
Manual cleaning, such as pail-and-brush, hand wipe, recirculating over-
spray (``sink-on-a-drum'') parts washers, immersion cleaning into dip
tanks with manual parts handling, and use of squirt bottles, is not
currently regulated under the SNAP program. EPA also does not regulate
the use of solvents as carriers for flame retardants, dry cleaning, or
paint stripping under the SNAP program.
This final action does not address the use of n-propyl bromide as
an aerosol solvent or as a carrier solvent in adhesives or coatings. We
are issuing a proposed rule addressing these end uses in a separate
Federal Register action. Neither this final nor the proposed rule issue
a decision on other end uses in which nPB was submitted as an ozone-
depleting substance (ODS) substitute, such as fire suppression or foam
blowing, because of insufficient information.
Affected users under this final rule could include:
Businesses that clean metal parts, such as automotive
manufacturers, machine shops, machinery manufacturers, and
electroplaters.
Businesses that manufacture electronics or computer
equipment.
Businesses that require a high level of cleanliness in
removing oil, grease, or wax, such as for aerospace applications or for
manufacture of optical equipment.
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Table 1.--Potentially Regulated Entities, by North American Industrial
Classification System (NAICS) Code or Subsector
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NAICS code
Category or Description of regulated
subsector entities
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Industry......................... 331 Primary Metal
Manufacturing.
Industry......................... 332 Fabricated Metal Product
Manufacturing.
Industry......................... 333 Machinery Manufacturing.
Industry......................... 334 Computer and Electronic
Product Manufacturing.
Industry......................... 335 Equipment Appliance, and
Component
Manufacturing.
Industry......................... 336 Transportation Equipment
Manufacturing.
Industry......................... 337 Furniture and Related
Product Manufacturing.
Industry......................... 339 Miscellaneous
Manufacturing.
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This table is not intended to be exhaustive, but rather a guide
regarding entities likely to be regulated by this action. If you have
any questions about whether this action applies to a particular entity,
consult the person listed in the preceding section, FOR FURTHER
INFORMATION CONTACT.
B. What is n-propyl bromide?
n-propyl bromide (nPB), also called 1-bromopropane, is a non-
flammable organic solvent with a strong odor. Its chemical formula is
C3H7Br. Its identification number in Chemical
Abstracts Service's registry (CAS Reg. No.) is 106-94-5. nPB is used to
remove wax, oil, and grease from electronics, metal, and other
materials. It also is used as a carrier solvent in adhesives. Some
brand names of products using nPB are: Abzol[supreg], EnSolv[supreg],
and Solvon[supreg] cleaners; Pow-R-Wash[supreg] NR Contact Cleaner,
Superkleen Flux Remover 2311 and LPS NoFlash NU Electro Contact Cleaner
aerosols; and Whisper Spray and Fire Retardant Soft Seam 6460
adhesives.
C. What acronyms and abbreviations are used in the preamble?
Below is a list of acronyms and abbreviations used in this
document.
8-hr--eight hour
ACGIH--American Conference of Governmental Industrial Hygienists
AEL--acceptable exposure limit
ASTM--American Society for Testing and Materials
BMD--benchmark dose
BMDL--benchmark dose lowerbound, the lower 95%-confidence level
bound on the dose/exposure associated with the benchmark response
BSOC--Brominated Solvents Consortium
CAA--Clean Air Act
CAS Reg. No.--Chemical Abstracts Service Registry Identification
Number
CBI--Confidential Business Information
CEG--community exposure guideline
CERHR--Center for the Evaluation of Risks to Human Reproduction
CFC-113--the ozone-depleting chemical 1,1,2-trifluoro-1,2,2-
trichloroethane, C2Cl3F3, CAS Reg.
No. 76-13-1
CFC--chlorofluorocarbon
cfm--cubic feet per minute
CFR--Code of Federal Regulations
CNS--central nervous system
DNA--deoxyribonucleic acid
EDSTAC--The Endocrine Disruptor Screening and Testing Advisory
Committee
EPA--the United States Environmental Protection Agency
FR--Federal Register
GWP--global warming potential
HCFC-123--the ozone-depleting chemical 1,2-dichloro-1,1,2-
trifluoroethane, CAS Reg. No. 306-83-2
HCFC-141b--the ozone-depleting chemical 1,1-dichloro-1-fluoroethane,
CAS Reg. No. 1717-00-6
HCFC-225ca/cb--the commercial mixture of the two ozone-depleting
chemicals 3,3-dichloro-1,1,1,2,2-pentafluoropropane, CAS Reg. No.
422-56-0 and 1,3-dichloro-1,1,2,2,3-pentafluoropropane, CAS Reg. No.
507-55-1
HCFC--hydrochlorofluorocarbon
HEC--human equivalent concentration
HFC-245fa--the chemical 1,1,3,3,3-pentafluoropropane, CAS Reg. No.
460-73-1
HFC-365mfc--the chemical 1,1,1,3,3-pentafluorobutane, CAS Reg. No.
405-58-6
HFC-4310mee--the chemical 1,1,1,2,3,4,4,5,5,5-decafluoropentane, CAS
Reg. No. 138495-42-8
HFC--hydrofluorocarbon
HFE--hydrofluoroether
HHE--health hazard evaluation
ICF--ICF Consulting
ICR--Information Collection Request
iPB--isopropyl bromide, C3H7Br, CAS Reg. No.
75-26-3, an isomer of n-propyl bromide; also called 2-bromopropane
or 2-BP
Koc--organic carbon partition coefficient, for
determining the tendency of a chemical to bind to organic carbon in
soil
LC50--the concentration at which 50% of test animals die
LOAEL--Lowest Observed Adverse Effect Level
Log Kow--logarithm of the octanol-water partition
coefficient, for determining the tendency of a chemical to
accumulate in lipids or fats instead of remaining dissolved in water
mg/l--milligrams per liter
MSDS--Material Safety Data Sheet
NAICS--North American Industrial Classification System
NESHAP--National Emission Standard for Hazardous Air Pollutants
NIOSH--National Institute for Occupational Safety and Health
NOAEL--No Observed Adverse Effect Level
NOEL--No Observed Effect Level
nPB-n-propyl bromide, C3H7Br, CAS Reg. No.
106-94-5; also called 1-bromopropane or 1-BP
NPRM--Notice of Proposed Rulemaking
NTP--National Toxicology Program
NTTAA--National Technology Transfer and Advancement Act
ODP--ozone depletion potential
ODS--ozone-depleting substance
OEHHA--Office of Environmental Health Hazard Assessment of the
California Environmental Protection Agency
OMB--U.S. Office of Management and Budget
OSHA--the United States Occupational Safety and Health
Administration
PCBTF--parachlorobenzotrifluoride, CAS Reg. No. 98-56-6
PEL--Permissible Exposure Limit
ppm--parts per million
RCRA--Resource Conservation and Recovery Act
RFA--Regulatory Flexibility Act
RfC--reference concentration
SIP--state implementation plan
SNAP--Significant New Alternatives Policy
STEL--Short term exposure limit
TCA--the ozone-depleting chemical 1,1,1-trichloroethane, CAS Reg.
No. 71-55-6; also called methyl chloroform, MCF, or 1,1,1
TCE--the chemical 1,1,2-trichloroethene, CAS Reg. No. 79-01-6,
C2Cl3H; also call trichloroethylene
TERA--Toxicological Excellence for Risk Assessment
TLV--Threshold Limit Value\TM\
TSCA--Toxic Substances Control Act
TWA--time-weighted average
UMRA--Unfunded Mandates Reform Act
U.S.C.--United States Code
VMSs--volatile methyl siloxanes
VOC--volatile organic compound
WEL--workplace exposure limit
II. How does the Significant New Alternatives Policy (SNAP) program
work?
A. What are the statutory requirements and authority for the SNAP
program?
Section 612 of the Clean Air Act (CAA) authorizes EPA to develop a
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program for evaluating alternatives to ozone-depleting substances,
referred to as the Significant New Alternatives Policy (SNAP) program.
The major provisions of section 612 are:
Rulemaking--Section 612(c) requires EPA to promulgate
rules making it unlawful to replace any class I (chlorofluorocarbon,
halon, carbon tetrachloride, methyl chloroform, and
hydrobromofluorocarbon) or class II (hydrochlorofluorocarbon) substance
with any substitute that the Administrator determines may present
adverse effects to human health or the environment where the
Administrator has identified an alternative that (1) reduces the
overall risk to human health and the environment, and (2) is currently
or potentially available.
Listing of Unacceptable/Acceptable Substitutes--Section
612(c) also requires EPA to publish a list of the substitutes
unacceptable for specific uses. We must publish a corresponding list of
acceptable alternatives for specific uses.
Petition Process--Section 612(d) grants the right to any
person to petition EPA to add a substitute to or delete a substitute
from the lists published in accordance with section 612(c). EPA has 90
days to grant or deny a petition. Where the Agency grants the petition,
we must publish the revised lists within an additional six months.
90-day Notification--Section 612(e) requires EPA to
require any person who produces a chemical substitute for a class I
substance to notify the Agency not less than 90 days before new or
existing chemicals are introduced into interstate commerce for
significant new uses as substitutes for a class I substance. The
producer must also provide the Agency with the producer's health and
safety studies on such substitutes.
Outreach--Section 612(b)(1) states that the Administrator
shall seek to maximize the use of federal research facilities and
resources to assist users of class I and II substances in identifying
and developing alternatives to the use of such substances in key
commercial applications.
Clearinghouse--Section 612(b)(4) requires the Agency to
set up a public clearinghouse of alternative chemicals, product
substitutes, and alternative manufacturing processes that are available
for products and manufacturing processes which use class I and II
substances.
B. How do the regulations for the SNAP program work?
On March 18, 1994, EPA published the original rulemaking (59 FR
13044) that described the process for administering the SNAP program
and issued the first acceptability lists for substitutes in the major
industrial use sectors. These sectors include: Refrigeration and air
conditioning; foam blowing; solvents cleaning; fire suppression and
explosion protection; sterilants; aerosols; adhesives, coatings and
inks; and tobacco expansion. These sectors comprise the principal
industrial sectors that historically consumed large volumes of ozone-
depleting substances.
Anyone who plans to market or produce a substitute for an ODS in
one of the eight major industrial use sectors must provide the Agency
with health and safety studies on the substitute at least 90 days
before introducing it into interstate commerce for significant new use
as an alternative. This requirement applies to the person planning to
introduce the substitute into interstate commerce, typically chemical
manufacturers, but may also include importers, formulators or end-users
when they are responsible for introducing a substitute into commerce.
C. How does the SNAP program list our decisions?
The Agency has identified four possible decision categories for
substitutes: Acceptable; acceptable subject to use conditions;
acceptable subject to narrowed use limits; and unacceptable. Use
conditions and narrowed use limits are both considered ``use
restrictions'' and are explained below. Substitutes that are deemed
acceptable with no use restrictions (no use conditions or narrowed use
limits) can be used for all applications within the relevant sector
end-use. Substitutes that are acceptable subject to use restrictions
may be used only in accordance with those restrictions. It is illegal
to replace an ODS with a substitute listed as unacceptable.
After reviewing a substitute, the Agency may make a determination
that a substitute is acceptable only if certain conditions of use are
met to minimize risks to human health and the environment. We describe
such substitutes as ``acceptable subject to use conditions.'' If you
use these substitutes without meeting the associated use conditions,
you use these substitutes in an unacceptable manner and you could be
subject to enforcement for violation of section 612 of the Clean Air
Act.
For some substitutes, the Agency may permit a narrowed range of use
within a sector. For example, we may limit the use of a substitute to
certain end-uses or specific applications within an industry sector or
may require a user to demonstrate that no other acceptable end uses are
available for their specific application. We describe these substitutes
as ``acceptable subject to narrowed use limits.'' If you use a
substitute that is acceptable subject to narrowed use limits, but use
it in applications and end-uses which are not consistent with the
narrowed use limit, you are using these substitutes in an unacceptable
manner and you could be subject to enforcement for violation of section
612 of the Clean Air Act.
The Agency publishes its SNAP program decisions in the Federal
Register. For those substitutes that are deemed acceptable subject to
use restrictions (use conditions and/or narrowed use limits), or for
substitutes deemed unacceptable, we first publish these decisions as
proposals to allow the public opportunity to comment, and we publish
final decisions as final rulemakings. In contrast, we publish
substitutes that are deemed acceptable with no restrictions in
``notices of acceptability,'' rather than as proposed and final rules.
As described in the rule implementing the SNAP program (59 FR 13044),
we do not believe that rulemaking procedures are necessary to list
alternatives that are acceptable without restrictions because such
listings neither impose any sanction nor prevent anyone from using a
substitute.
Many SNAP listings include ``comments'' or ``further information.''
These statements provide additional information on substitutes that we
determine are either unacceptable, acceptable subject to narrowed use
limits, or acceptable subject to use conditions. Since this additional
information is not part of the regulatory decision, these statements
are not binding for use of the substitute under the SNAP program.
However, regulatory requirements listed in this column are binding
under other programs. The further information does not necessarily
include all other legal obligations pertaining to the use of the
substitute. However, we encourage users of substitutes to apply all
statements in the FURTHER INFORMATION column in their use of these
substitutes. In many instances, the information simply refers to sound
operating practices that have already been identified in existing
industry and/or building-code standards. Thus, many of the comments, if
adopted, would not require the affected industry to make significant
changes in existing operating practices.
D. Where can I get additional information about the SNAP program?
For copies of the comprehensive SNAP lists of substitutes or
additional information on SNAP, look at EPA's
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Ozone Depletion World Wide Web site at http://www.epa.gov/ozone/snap/lists/index.html. For more information on the Agency's process for
administering the SNAP program or criteria for evaluation of
substitutes, refer to the SNAP final rulemaking published in the
Federal Register on March 18, 1994 (59 FR 13044), codified at Code of
Federal Regulations at 40 CFR part 82, subpart G. You can find a
complete chronology of SNAP decisions and the appropriate Federal
Register citations at http://www.epa.gov/ozone/snap/chron.html.
III. What is EPA's final listing decision on nPB in solvent cleaning?
The Agency is listing nPB as an acceptable substitute in metals,
precision and electronics cleaning end uses. Based on the available
information, we find that nPB can be used with no substantial increase
in overall risks to human health and the environment, compared to other
available or potentially available substitutes for ozone-depleting
substances in these end uses.
EPA is issuing today's listing in the form of a final rule, rather
than in a notice of acceptability, in order to respond to the public
comments received on a Notice of Proposed Rulemaking (NPRM) that we
issued on June 3, 2003 (68 FR 33284). In that rule, we proposed listing
n-propyl bromide (nPB) as an acceptable substitute for use in metals,
precision, and electronics cleaning, and in aerosols and adhesives end-
uses, subject to the use condition that nPB used in these applications
contains no more than 0.05% by weight of isopropyl bromide. In
addition, in that proposed rule, EPA indicated that we also would
recommend that users adhere to a voluntary acceptable exposure limit
(AEL) of 25 parts per million averaged over an eight-hour time-weighted
average (TWA). Based on new information received after the close of the
comment period on the June 2003 NPRM relevant to our proposed
determinations for adhesive and aerosol solvent end uses in that same
proposal, the Agency is issuing a new proposal for those end uses in a
separate Federal Register action. The Agency is not including a
recommended AEL in this final rule.
Table 2 contains the text pertaining to nPB use in solvent cleaning
end-uses that will be added to EPA's list of acceptable substitutes
located on the SNAP Web site at http://www.epa.gov/ozone/snap/lists/index.html. This and other listings for substitutes that are acceptable
without restriction are not included in the Code of Federal Regulations
because they are not regulatory requirements. The information contained
in the ``Further Information'' column of those tables are non-binding
recommendations on the safe use of substitutes.
Table 2.--Solvent Cleaning Acceptable Substitute
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End use Substitute Decision Further information
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Metals cleaning, electronics n-propyl bromide (nPB) Acceptable............ EPA recommends the use of
cleaning, and precision cleaning. as a substitute for personal protective
CFC-113 and methyl equipment, including
chloroform. chemical goggles, flexible
laminate protective gloves
and chemical-resistant
clothing.
EPA expects that all users
of nPB would comply with
any final Permissible
Exposure Limit that the
Occupational Safety and
Health Administration
issues in the future under
42 U.S.C. 7610(a).
nPB, also known as 1-
bromopropane, is Number
106-94-5 in the Chemical
Abstracts Service (CAS)
Registry.
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IV. What criteria did EPA consider in making this final determination?
In the original rule implementing the SNAP program (March 18, 1994;
59 FR 13044, at 40 CFR 82.180(a)(7)), the Agency identified the
criteria we use in determining whether a substitute is acceptable or
unacceptable as a replacement for class I or II compounds:
(i) Atmospheric effects and related health and environmental
impacts; [e.g., ozone depletion potential]
(ii) General population risks from ambient exposure to compounds
with direct toxicity and to increased ground-level ozone;
(iii) Ecosystem risks [e.g., bioaccumulation, impacts on surface
and groundwater];
(iv) Occupational risks;
(v) Consumer risks;
(vi) Flammability; and
(vii) Cost and availability of the substitute.
In this review, EPA considered all the criteria above. However, n-
propyl bromide is used in industrial applications such as electronics
cleaning. In those consumer products made using nPB, such as a
computer, the nPB would have evaporated long before a consumer would
purchase the item. Therefore, we believe there is no consumer exposure
risk in the end uses we evaluated for this rule.
Section 612(c) of the Clean Air Act directs EPA to publish a list
of replacement substances (``substitutes'') for class I and class II
ozone depleting substances based on whether the Administrator
determines they are safe (when compared with other currently or
potentially available substitutes) for specific uses or are to be
prohibited for specific uses. EPA must compare the risks to human
health and the environment of a substitute to the risks associated with
other substitutes that are currently or potentially available. In
addition, EPA also considers whether the substitute for class I and
class II ODSs ``reduces the overall risk to human health and the
environment'' compared to the ODSs being replaced. Our evaluation is
based on the end use; for example, we compared nPB as a metal cleaning
solvent against other available or potentially available metal cleaning
alternatives.
Although EPA does not judge the effectiveness of an alternative for
purposes of determining whether it is acceptable, we consider
effectiveness when determining whether alternatives that pose less risk
are available in a particular application within an end use. There are
a wide variety of acceptable alternatives listed for solvent cleaning,
but not all are appropriate for a specific application because of
differences in soils, materials compatibility, degree of cleanliness
required, local environmental requirements, and other factors. For
example, aqueous cleaners are effective cleaners in many situations and
are the substitute of choice for many in the metal cleaning end use.
However, in some specific precision cleaning applications that require
a high degree of cleanliness and that have narrow
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spaces that may trap water used in rinsing, aqueous cleaners may not be
appropriate and thus are not available in those specific applications.
EPA evaluated each of the criteria separately and then considered
overall risk to human health and the environment in comparison to other
available or potentially available alternatives. We concluded that
overall, while there are a number of alternatives that reduce the risks
from ozone depletion or from smog production \1\ slightly more than nPB
when used in industrial solvent cleaning equipment, we found no single
alternative that could work in all applications that clearly would
reduce overall risks to human health and the environment in metals
cleaning, electronics cleaning, and precision cleaning. Balancing the
different criteria discussed below, nPB used in solvent cleaning end-
uses does not pose a significantly greater risk than other substitutes
or than the ODS it is replacing in these end uses. Thus, we are listing
nPB as acceptable in metals cleaning, electronics cleaning, and
precision cleaning.
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\1\ Smog, also known as ground-level ozone, is produced from
emissions of volatile organic compounds that react under certain
conditions of temperature and light.
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A. Availability of Alternatives to Ozone-Depleting Substances
Other alternatives to methyl chloroform and CFC-113 are available
for metals, electronics, and precision cleaning that have already been
found acceptable or acceptable subject to use conditions under the SNAP
program including: Aqueous cleaners, semi-aqueous cleaners, alcohols,
ketones, esters, ethers, terpenes, HCFC-225ca/cb, hydrofluoroethers
(HFEs), hydrofluorocarbon (HFC)-4310mee, HFC-365mfc,
heptafluorocyclopentane, hydrocarbons, volatile methyl siloxanes
(VMSs), trans-1,2-dichloroethylene, methylene chloride,
trichloroethylene \2\ (TCE), perchloroethylene,\3\
parachlorobenzotrifluoride (PCBTF), and alternative technologies like
supercritical fluids, plasma cleaning, and ultraviolet/ozone cleaning.
Some alternatives are unlikely to be used in particular end uses
because of constraints such as cleaning performance, materials
compatibility, cost, workplace exposure requirements, or flammability.
For example, no-clean technology is used in electronics cleaning and
not in precision cleaning because of the need for a high degree of
cleanliness in precision cleaning. Of the available substitutes,
aqueous cleaners or solvents for vapor degreasing such as TCE, blends
of alcohols or trans-1,2-dichloroethylene and HFCs or HFEs, and HCFC-
225ca/cb are most likely to be used in the same applications as nPB.
nPB is already commercially available in solvent cleaning, and is used
mostly for vapor degreasing in the electronics and precision cleaning
end uses (IBSA, 2002).
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\2\ Also called trichlorethene or TCE,
C2Cl3H, CAS Reg. No. 79-01-6.
\3\ Also called PERC, tetrachloroethylene, or tetrachloroethene,
C2Cl4, CAS Reg. No. 172-18-4.
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B. Impacts on the Atmosphere and Local Air Quality
As discussed in the June 2003 proposal, nPB emissions from the
continental United States are estimated to have an ozone depletion
potential (ODP) of approximately 0.013-0.018, (Wuebbles, 2002) \4\,
lower than that of the ozone depletion potential of the substances that
nPB would replace--CFC-113 (ODP=1.0), and methyl chloroform and HCFC-
141b (ODPs = 0.12) (WMO, 2002). Some other acceptable alternatives for
these ODSs also have low ODPs. For example, HCFC-225ca/cb has an ODP of
0.02-0.03 (WMO, 2002) and is acceptable in metals cleaning and aerosol
solvents, and acceptable subject to use conditions in precision
cleaning and electronics cleaning. HCFC-123 has an ODP of 0.02 (WMO,
2002), and is an acceptable substitute in precision cleaning. There are
other acceptable cleaners that essentially have no ODP--aqueous
cleaners, HFEs, HFC-4310mee, HFC-365mfc, HFC-245fa, hydrocarbons, VMSs,
methylene chloride, TCE, perchloroethylene, and PCBTF.
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\4\ nPB emissions in the tropics have an ODP of 0.071 to 0.100;
the portions of the U.S. outside the continental U.S., such as
Alaska, Hawaii, Guam, and the U.S. Virgin Islands, contain less than
1 percent of the U.S.'s businesses in industries that could use nPB.
Thus, their potential impact on the ozone layer must be
significantly less than that of the already low impact from nPB
emissions in the continental U.S. (U.S. Economic Census, 2002a
through f).
---------------------------------------------------------------------------
The global warming potential (GWP) index is a means of quantifying
the potential integrated climate forcing of various greenhouse gases
relative to carbon dioxide. Earlier data found a direct 100-year
integrated GWP (100yr GWP) for nPB of 0.31 (Atmospheric and
Environmental Research, Inc., 1995). More recent analysis that
considers both the direct and the indirect GWP of nPB found a 100-yr
GWP of 1.57 (ICF, 2003a; ICF, 2006a). In either case, the GWP for nPB
is comparable to or below that of previously approved substitutes in
these end uses.
Use of nPB may be controlled as a volatile organic compound (VOC)
under state implementation plans (SIPs) developed to attain the
National Ambient Air Quality Standards for ground-level ozone, which is
a respiratory irritant. Users located in ozone non-attainment areas may
need to consider using a substitute for cleaning that is not a VOC or
if they choose to use a substitute that is a VOC, they may need to
control emissions in accordance with the SIP. Companies have petitioned
EPA, requesting that we exempt nPB from regulation as a VOC. However,
unless and until EPA issues a final rulemaking exempting a compound
from the definition of VOC and states change their SIPs to exclude such
a compound from regulation, that compound is still regulated as a VOC.
Other acceptable ODS-substitute solvents that are VOCs for state air
quality planning purposes include most oxygenated solvents such as
alcohols, ketones, esters, and ethers; hydrocarbons and terpenes;
trichloroethylene; trans-1,2-dichloroethylene; monochlorotoluenes; and
benzotrifluoride. Some VOC-exempt solvents that are acceptable ODS
substitutes include HFC-245fa for aerosol solvents; HCFC-225ca/cb, HFC-
365mfc and HFC-4310mee for metals electronics, and precision cleaning
and aerosol solvents; and methylene chloride, perchloroethylene, HFE-
7100, HFE-7200, PCBTF, acetone, and methyl acetate for metals,
electronics, and precision cleaning, aerosol solvents, adhesives, and
coatings.
C. Ecosystem and Other Environmental Impacts
EPA considered the possible impacts of nPB if it were to pollute
soil or water as a waste and compared these impacts to screening
criteria developed by the Endocrine Disruptor Screening and Testing
Advisory Committee (EDSTAC, 1998) (see Table 3). Available data on the
organic carbon partition coefficient (Koc), the breakdown
processes in water and hydrolysis half-life, and the volatilization
half-life indicate that nPB is less persistent in the environment than
many solvents and would be of low to moderate concern for movement in
soil. Based on the LC50, the acute concentration at which
50% of tested animals die, nPB's toxicity to aquatic life is moderate,
being less than that for some acceptable cleaners (for example,
trichloroethylene, hexane, d-limonene, and possibly some aqueous
cleaners) and greater than that for some others (methylene chloride,
acetone, isopropyl alcohol, and some other aqueous cleaners). The
LC50 for nPB is 67 mg/l, which is greater than 10 mg/l.
Based on EPA's criteria for listing under the Toxics Release Inventory
(U.S. EPA,
[[Page 30147]]
1992), we believe that nPB would not be sufficiently toxic to aquatic
life to warrant listing under the Toxics Release Inventory. Based on
its relatively low bioconcentration factor and log Kow
value, nPB is not prone to bioaccumulation. Table 3 summarizes
information on environmental impacts of nPB; trans-1,2-
dichloroethylene, a commonly-used solvent in blends for aerosol
solvents, precision cleaning, and electronics cleaning;
trichloroethylene, a solvent used for metals, electronics, and
precision cleaning; and methyl chloroform, an ODS that nPB would
replace.
Table 3.--Ecosystem and Other Environmental Properties of nPB and Other Solvents
--------------------------------------------------------------------------------------------------------------------------------------------------------
Description of Value for trans-1,2- Value for Value for methyl
Property environmental property Value for nPB dichloro-ethylene trichloroethylene chloroform
--------------------------------------------------------------------------------------------------------------------------------------------------------
Koc, organic-carbon partition Degree to which a 330 (Source: ICF, 32 to 49 (Source: 106 to 460 (Source: 152 (Source: U.S.
coefficient. substance tends to stick 2004a). ATSDR, 1996). ATSDR, 1997). EPA, 1994a).
to soil or move in soil.
Lower values (< 300)*
indicate great soil
mobility; values of 300
to 500 indicate moderate
mobility in soil.
Break down in water............... Mechanism and speed with Hydrolysis is Photolytic Volatilization and Volatilization most
which a compound breaks significant. decomposition, biodegradation most significant;
down in the environment. Hydrolysis half- dechlorination and significant, with biodegradation and
(Hydrolysis half-life life of 26 days biodegradation are hydrolysis relatively hydrolysis also
values > 25 weeks* are of (Source: ICF, significant; insignificant. occur (Source:
concern.) 2004a). hydrolysis not Hydrolysis half-life ATSDR, 2004).
significant of 10.7 to 30 months
(Source: ATSDR, (Source: ATSDR, 1997).
1996).
Volatilization half-life from Tendency to volatilize and 3.4 hours-4.4 days 3 to 6.2 hours 3.4 hours to 18 days Hours to weeks
surface waters. pass from water into the (Source: ICF, (Source: ATSDR, (Source: ATSDR, 1997). (Source: U.S. EPA,
air. 2004a). 1996). 1994a).
LC50 (96 hours) for fathead Concentration at which 50% 67 mg/L (Source: 108 mg/L (Source: 40.7 to 66.8 mg/L 52.8 to 105 mg/L
minnows. of animals die from Geiger, 1988). U.S. EPA, 1980). (Source: NPS, 1997). (Source: U.S. EPA,
toxicity after exposure 1994a).
for 4 days.
log Kow........................... Logarithm of the octanol/ 2.10 (Source: ICF, -0.48 (Source: 2.38 (Source: LaGrega 2.50 (Source:
water partition 2004a). LaGrega et al., et al., 2001, p. LaGrega et al.,
coefficient, a measure of 2001, p. 1119). 1127). 2001, p. 1127).
tendency to accumulate in
fat. Log Kow values >3*
indicate high tendency to
accumulate.
Bioconcentration factor........... High factors (>1000)* 23 (Source: HSDB, 5 to 23 (Source: 10 to 100 (Source: <9 (Source: U.S.
indicate strong tendency 2004). ATSDR, 1996). ATSDR, 1997). EPA, 1994a).
for fish to absorb the
chemical from water into
body tissues.
--------------------------------------------------------------------------------------------------------------------------------------------------------
*Criteria from EDSTAC, 1998.
nPB is not currently regulated as a hazardous air pollutant and is
not listed as a hazardous waste under the Resource Conservation and
Recovery Act (RCRA). nPB is not required to be reported as part of the
Toxic Release Inventory under Title III of the Superfund Amendments and
Reauthorization Act. Despite this, large amounts of nPB might be
harmful if disposed of in water. We recommend that users dispose of nPB
as they would dispose of any spent halogenated solvent (F001 waste
under RCRA). Users should not dump nPB into water, and should dispose
of it by incineration.
D. Flammability and Fire Safety
A number of commenters on the June 2003 proposal provided
additional information on the flammability of nPB using standard test
methods for determining flash point, such as the American Society for
Testing and Materials (ASTM) D 92 open cup, ASTM D56 Tag closed cup,
and ASTM D93 Pensky-Martens closed cup methods (BSOC, 2000; Miller,
2003; Morford, 2003a, b and c; Shubkin, 2003; Weiss Cohen, 2003). We
agree with the commenters that by these standard test methods, nPB
displayed no flash point. Thus under standard test conditions, nPB is
not flammable, and it should not be flammable under normal use
conditions. With its low potential for flammability, nPB is comparable
to chlorinated solvents, HCFCs, HFEs, HFC-245fa, HFC-4310mee, and
aqueous cleaners, and is less flammable than many acceptable
substitutes, such as ketones, alcohols, terpenes, and hydrocarbons. nPB
exhibits lower and upper flammability limits of approximately 3% to 8%
(BSOC, 2000). A number of other solvents that are typically considered
to be non-flammable also have flammability limits (for example,
methylene chloride, HCFC-141b, and methyl chloroform). If the
concentration of vapor of such a solvent falls between the upper and
lower flammability limits, it could catch fire in presence of a flame.
Such a situation is unusual, but users should take appropriate
precautions in cases where the concentration of vapor could fall
between the flammability limits.
E. Impact on Human Health
In evaluating potential human health impacts of nPB, EPA considered
impacts on both exposed workers and on the general population because
we identified these groups of people as the ones likely to be exposed
to nPB when it is used as a substitute for ozone-depleting substances.
EPA evaluated the available toxicity data using EPA guidelines to
develop health-based criteria to characterize human health risks (U.S.
EPA, 1994b. RfC Guidelines; U.S. EPA, 1991. Guidelines for
Developmental Toxicity Risk Assessment; U.S. EPA, 1995b. Benchmark Dose
guidelines; U.S. EPA, 1996. Guidelines for Reproductive Toxicity Risk
Assessment).
[[Page 30148]]
In the June 2003 NPRM, EPA proposed that an exposure limit of 25
ppm would be protective of a range of effects observed in animal and
human studies, including reproductive and developmental toxicity,
neurotoxicity, and hepatotoxicity. Reduction of sperm motility in rats,
noted across multiple studies at relatively low exposures, was
determined to be the most sensitive effect. The Agency derived an
exposure limit of 18 ppm from a dose response relationship in male rat
offspring (``F1 generation'') whose parents were exposed to nPB from
prior to mating through birth and weaning of the litters (WIL Research
Laboratories, 2001). We then proposed to adjust this value upwards to
25 ppm based on principles of risk management consistent with one of
the original ``Guiding Principles'' of the SNAP program (59 FR 13046,
March 18, 1994). As we discussed in the June 2003 NPRM, EPA noted that
adhesives users should be able to achieve an AEL of 25 ppm and that 25
ppm was between the level based on the most sensitive endpoint (sperm
motility in the F1 offspring generation) and the second most sensitive
endpoint (sperm motility in the F0 parental generation). Following SNAP
program principles, we noted that ``a slight adjustment of the AEL may
be warranted after applying judgment based on the available data and
after considering alternative derivations'' (69 FR 33295). We stated
further that ``18 ppm is a reasonable but possibly conservative
starting point, and that exposure to 25 ppm would not pose
substantially greater risks, while still falling below an upper bound
on the occupation[al] exposure limit.''
As part of this final rulemaking, the Agency has reviewed both
information available at the time of the 2003 NPRM related to the
health risks associated with nPB use, as well as more recent case
studies of nPB exposures and effects in the workplace, newly published
toxicological studies, comments to the NPRM, new risk assessments on
nPB, and a new threshold limit value (TLV) issued by the American
Council of Government and Industrial Hygienists (ACGIH). The new
information is reviewed in greater detail in EPA's proposal specific to
the use of nPB in aerosol solvents, adhesives, and coatings.
Some general conclusions we draw from the new studies include:
New data from toxicological studies on nervous system
effects remain inconsistent and equivocal concerning the level at which
nervous system effects occur (Fueta et al., 2002; Fueta et al., 2004;
Honma et al., 2003; Ishidao et al., 2002, NTP, 2003; Sohn et al. 2002,
Wang et al., 2003).
Case reports of nPB exposure in the workplace indicate
that severe, possibly irreversible, neurological effects may occur at
sustained concentrations of approximately 100 ppm or greater (Beck and
Caravati, 2003; Majersik et al., 2004; Majersik et al., 2005; Ichihara
et al., 2002; Miller, 2005; Raymond and Ford, 2005). In other cases,
similar or higher concentrations up to 170 ppm caused less severe
nervous system effects (Nemhauser, 2005; NIOSH, 2003a; Ichihara,
2004a). Some neurological effects occurred in workers at levels of less
than 50 ppm (Ichihara et al., 2004b). Because of design and
methodological limitations, such as small numbers of subjects and
limited exposure information, these studies do not provide a sufficient
quantitative basis to derive an acceptable exposure limit.
Data on female rats indicate that nPB affects the
maturation of ovarian follicles and the ovarian cycle (Yamada et al.,
2003), consistent with previously reviewed data (WIL, 2001; Sekiguchi
et al., 2002).
Some data on occupation exposure suggest that workers
exposed to nPB may have experienced menstrual disorders (Ichihara et
al., 2002; Ichihara et al., 2004b). However, the data are not
statistically significant and are not sufficient to conclude that nPB
exposure caused these female reproductive effects.
Data on DNA damage in workers exposed to nPB was not
statistically significant (Toraason et al., 2006).
Metabolic data on mice and rats indicate some species
differences. Metabolism of nPB appears to be primarily through
cytochrome P450 enzymes, particularly in mice; glutathione conjugation
also plays a role, and a bigger role for rats than for mice (RTI,
2005).
These more recent studies do not cause us to change our acceptability
determination for solvent cleaning.
In addition, we considered new evaluations of the toxicity of nPB
from Stelljes and Wood (2004), Toxicological Excellence in Risk
Assessment (TERA, 2004), ICF (2004a, 2006a), and the TLV documentation
from the ACGIH (ACGIH, 2005).
Stelljes and Wood (2004) is similar in its results to SLR
International (2001), a study by the same authors. EPA previously
reviewed SLR International, 2001 in developing the June 2003 NPRM. Both
these studies concluded with a recommended AEL of 156 ppm, based on
male reproductive effects and uncertainty factors of 1 in driving the
AEL. These documents assigned uncertainty factors in a manner
inconsistent with EPA's guidance. This would result in a higher AEL
than we would determine following the approach EPA has used on other
chemicals, as well as an AEL that in our view would not sufficiently
protect human health from nPB's effects because of multiple sources of
uncertainty in available data (i.e., variability within the working
population and differences between animals and humans in how nPB
affects the reproductive system).
TERA (2004) reviews other AEL derivations for nPB,
performs a benchmark dose (BMD) analysis, and recommends an AEL of 20
ppm based on live litter size. This document is consistent with EPA
guidance for BMD modeling and for assigning uncertainty factors. A
review of this document is available in the public docket (ICF, 2004b).
ICF (2004c, 2006b) derived an AEL for nPB based upon
female reproductive effects. ICF (2004c, 2006b) discussed the relevant
literature (Ichihara et al., 1999, 2002, 2004a, 2004b; Sekiguchi, 2002;
Yamada et al., 2003; WIL, 2001) and calculated mean estrous cycle
length and the mean number of estrous cycles occurring during a three-
week period at different exposure levels in the WIL, 2001 2-generation
study. ICF (2004c, 2006a) found statistically significant reductions in
the number of estrous cycles in a three-week period, both including and
excluding females that had stopped their estrous cycles, at 250, 500,
and 750 ppm in the F0 parental generation and at 500 and 750 ppm in the
F1 generation. ICF (2004c, 2006a) conducted BMD modeling and calculated
benchmark dose lowerbound (BMDL) values of the number of estrous cycles
in a three-week period that varied from 102 to 208 ppm, depending upon
the model used and the benchmark criteria selected. All data were
calculated based on the mean reductions in estrous cycle number
calculated from the WIL, 2001 study. Values were calculated for the F0
generation; the number of data for the F1 generation was too small for
statistical analysis. The BMDLs that ICF calculated for the number of
estrous cycles in a three-week period were 162 ppm and 208 ppm,
depending on the benchmark response criteria (10% change in response
vs. one standard deviation) and using a linear-heterogeneous model.
The ACGIH issued a recommended TLV of 10 ppm (time-
weighted average) for nPB (ACGIH, 2005). ACGIH summarized numerous
studies showing
[[Page 30149]]
different effects of nPB and identified no observed effect levels
(NOELs) of 200 ppm for hepatotoxicity (ClinTrials, 1997b) and less than
100 ppm for developmental toxicity, as evidenced by decreased fetal
weight (Huntingdon Life Sciences, 2001).
The Occupational Safety and Health Administration (OSHA) has not
developed a permissible exposure limit (PEL) for nPB that EPA could use
to evaluate toxicity risks \5\ from workplace exposure. In prior SNAP
reviews, EPA has used ACGIH TLVs where available in assessing a
chemical's risks and determining its acceptability if OSHA has not set
a PEL. ACGIH is recognized as an independent, scientifically
knowledgeable organization with expertise in issues of toxicity and
industrial hygiene. However, in this case, EPA believes that ACGIH's
TLV for nPB of 10 ppm has significant limitations as a reliable basis
for an acceptable exposure limit, especially given the availability of
other, more comprehensive analyses described in this preamble. First,
according to the authors of the Huntingdon Life Sciences study, the
decrease in fetal weight was an artifact of sampling procedure that
biased the data (test animals were only sacrificed at the end of the
day rather than at random). The Center for the Evaluation of Risks to
Human Reproduction (CERHR) expert panel excluded ``aberrantly low''
fetal weights from one litter in this study and calculated a BMDL
greater than 300 ppm for this endpoint after removing those outlier
data (CERHR, 2002a, 2003a, and 2004a). TERA calculated a BMDL similar
to that of the CERHR expert panel when analyzing the same data set
(TERA, 2004). Further, the reference list in the documentation on the
TLV indicates that ACGIH did not review and evaluate all the studies
available prior to the development of the recommended exposure limit.
For example, key supporting articles that reported disruption of
estrous cycles (Yamada et al., 2003 and Sekiguchi et al., 2002) were
not discussed in the TLV documentation. Further, ACGIH did not provide
sufficient reasoning for the selection of the chosen endpoint over
others (e.g., reproductive toxicity and/or neurotoxicity). The lack of
discussion of applied uncertainty factors also prevents a determination
of how ACGIH arrived at a TLV of 10 ppm. In summary, EPA is not basing
its proposed acceptability determination for nPB on the ACGIH TLV
because: (1) Other scientists evaluating the database for nPB did not
find the reduced pup weight to be the most sensitive endpoint; (2) BMD
analysis of the reduced pup weight data (CERHR, 2002a; TERA, 2004)
results in a higher BMDL (roughly 300 ppm) than those for sperm effects
and estrous cycle changes; and (3) ACGIH may not have reviewed the
complete body of literature as several studies discussing neurotoxicity
and female reproductive effects were omitted from the list of
references. A number of reviews of this document are available in the
public docket (ICF, 2004d; O'Malley, 2004). Despite some flaws in its
derivation, the TLV of 10 ppm is less than two-fold lower than the low
end of the range of acceptable exposure levels based on the most
sensitive reproductive endpoints (see below). This small difference is
well within the uncertainty we see when extrapolating a benchmark dose
from an experimental study in rats to an occupational exposure limit in
humans.
---------------------------------------------------------------------------
\5\ Vendors of nPB-based products have recommended a wide range
of exposure limits, from 5 ppm to 100 ppm (Albemarle, 2003;
Chemtura, 2006; Docket A-2001-07, item II-D-19; Enviro Tech
International, 2006; Farr, 2003; Great Lakes Chemical Company,
2001).
---------------------------------------------------------------------------
We summarize the data for a number of end points found in these
analyses in Table 4 below. We examined these data to assess the
acceptability of nPB use in the metals, electronics, and precision
cleaning end uses reviewed in this final rule. These data indicate
that, once uncertainty factors are applied consistent with EPA
guidelines, the lowest levels for acceptable exposures would be derived
for reproductive effects.\6\ The data also indicate that a level
sufficient to protect against male reproductive effects (e.g., reduced
sperm motility) would be in a range from 18 to 30 ppm, in the range of
17 to 22 ppm to protect against female reproductive effects (e.g.,
estrous cycle length), and at approximately 20 ppm for effects related
to reproductive success (live litter size).
---------------------------------------------------------------------------
\6\ By EPA guidelines, we would apply an uncertainty factor of
[radic]10, or approximately 3, for differences between species for
all health effects. We would also apply an uncertainty factor of
[radic]10 (3) for variability within the working population for
reproductive and developmental effects, because, among other
reasons, these conditions would not necessarily screen out an
individual from being able to work, unlike for liver or nervous
system effects. Therefore, for reproductive and developmental
effects, we use a composite uncertainty factor of 10. See further
discussion of uncertainty factors in section V.B.3 below.
Table 4.--Summary of Endpoints Using Benchmark Response Modeling
----------------------------------------------------------------------------------------------------------------
Human
equivalent
Endpoint \a\ Study BMDL\b\ concentration
(ppm) (HEC)\c\
(ppm)
----------------------------------------------------------------------------------------------------------------
Liver Effects \d\
----------------------------------------------------------------------------------------------------------------
Liver vacuolation in males (F1 offspring WIL, 2001 as analyzed in ICF, 2002... 110 116
generation).
Liver vacuolation in males (F0 parent WIL, 2001 as analyzed in ICF, 2002... 143 150
generation).
Liver vacuolation............................ ClinTrials, 1997b as analyzed in ICF, 226 170
2002 and Stelljes & Wood, 2004.
----------------------------------------------------------------------------------------------------------------
Reproductive Effects--Male
----------------------------------------------------------------------------------------------------------------
Sperm motility (F1 offspring generation)..... WIL, 2001 as analyzed in ICF, 2002... 169 177
WIL, 2001 as analyzed in Stelljes & 156 164
Wood, 2004.
Sperm motility (F0 parent generation)........ WIL, 2001 as analyzed in ICF, 2002... 282 296
WIL, 2001 as analyzed in Stelljes & 263 276
Wood, 2004.
Prostate weight (F0 parent generation)....... WIL, 2001 as analyzed in TERA, 2004.. 190 200
Sperm count.................................. Ichihara et al., 2000b as analyzed in 232 325
Stelljes & Wood, 2004.
[[Page 30150]]
Sperm deformities (F0 parent generation)..... WIL, 2001 as analyzed in Stelljes & 296 311
Wood, 2004.
----------------------------------------------------------------------------------------------------------------
Reproductive Effects--Female
----------------------------------------------------------------------------------------------------------------
Number of estrus cycles during a 3 week WIL, 2001 as analyzed in ICF, 2006a.. 162 170
period (F0 parent generation).
WIL, 2001 as analyzed in ICF, 2006a.. 208 218
Estrous cycle length (F1 offspring WIL, 2001 as analyzed in TERA, 2004.. 400 420
generation) \d\.
Estrous cycle length (F0 parent generation) WIL, 2001 as analyzed in TERA, 2004.. 210 220
\e\.
No estrous cycle incidence (F1 offspring WIL, 2001 as analyzed in TERA, 2004.. 180 189
generation).
No estrous cycle incidence (F0 parent WIL, 2001 as analyzed in TERA, 2004.. 480 504
generation).
----------------------------------------------------------------------------------------------------------------
Reproductive Effects--Reproductive Success
----------------------------------------------------------------------------------------------------------------
Decreased live litter size (F1 offspring WIL, 2001 as analyzed in TERA, 2004.. 190 200
generation).
Decreased live litter size (F2 offspring WIL, 2001 as analyzed in TERA, 2004.. 170 179
generation).
Pup weight gain, post-natal days 21 to 28 (F1 WIL, 2001 as analyzed in TERA, 2004.. 180 189
offspring generation).
----------------------------------------------------------------------------------------------------------------
Developmental Effects
----------------------------------------------------------------------------------------------------------------
Fetal body weight............................ WIL, 2001 as analyzed in TERA, 2004.. 310 326
Fetal body weight............................ WIL, 2001 as analyzed in CERHR, 2002a 305 320
----------------------------------------------------------------------------------------------------------------
Nervous System Effects
----------------------------------------------------------------------------------------------------------------
Hindlimb strength............................ Ichihara et. al., 2000a as analyzed 214 300
in Stelljes and Wood, 2004.
----------------------------------------------------------------------------------------------------------------
\a\ Unless explicitly stated, data are from a parental generation. Of the studies analyzed, only the WIL, 2001
study has multiple generations to be analyzed.
\b\ The benchmark response value represents a specified level of excess risk above a control response.
\c\ When considering workplace exposures, the human equivalent concentration is the BMDL, adjusted to apply to a
40-hour work week in which workers are exposed for 8 hours a day for five days per week. Animals in the WIL,
2001 study were exposed for 6 hours a day, 7 days a week. Animals in the Ichihara, 2000a and 2000b studies
were exposed for 8 hours a day, 7 days a week. Animals in the ClinTrials, 1997b study were exposed for 6 hours
a day, 5 days a week.
\d\ After applying an uncertainty factor of 3 for animal to human extrapolation, acceptable levels of exposure
to protect against liver effects would be in the range of 39 to 57 ppm.
\e\ Omits data from those animals that have stopped estrous cycling altogether (TERA, 2004).
These more recent evaluations do not change EPA's acceptability
determination for solvent cleaning. As discussed below, users of
solvent cleaning equipment are reliably able to achieve exposure levels
well below our proposed AEL of 25 ppm in the June 2003 NPRM and
therefore we expect nPB users in the metals, electronics, and precision
cleaning end uses to be able to achieve acceptable exposure levels.
Concentrations of nPB emitted from industrial solvent cleaning
equipment were found to be below 25 ppm in roughly 88% of 500 samples
on an 8-hr time-weighted average, below 18 ppm in 81% of these samples,
and below 10 ppm in roughly 70% of these samples (U.S. EPA, 2003).
Based on review of the previously available information and
information submitted in comments to the NPRM, the Agency believes that
its derivation of 18 ppm as a starting point in the development of a
recommended acceptable exposure level is still valid. For purposes of
assessing the acceptability of nPB use in solvent cleaning
applications, the Agency evaluated whether exposure levels expected to
result from solvent cleaning would approach either the 2003 proposed
recommended AEL of 25 ppm, or the more conservative starting point of
18 ppm which was derived from the Agency's original risk analysis. We
also evaluated any potential risks to the general population associated
with nPB use as a solvent.
1. Workplace Risks
EPA believes that the great majority of users of nPB in metals
cleaning, electronics cleaning, and precision cleaning have been able
to attain exposure levels of well below 25 ppm, the proposed AEL in the
2003 NPRM, with their existing equipment. Recently measured exposure
levels for nPB are much lower than historic exposure data from the
1970s and 1980s for metals cleaning and electronics cleaning (ICF,
2006a); this reflects both improvements in industrial hygiene practices
and improvements in cleaning equipment since 1994 spurred by the
National Emission Standard for Hazardous Air Pollutants for Halogenated
Solvent Cleaning (59 FR 61801). Concentrations
[[Page 30151]]
of nPB emitted from industrial solvent cleaning equipment were found to
be below 25 ppm in roughly 88% of 500 samples on an 8-hr time-weighted
average, below 18 ppm in 81% of these samples, and below 10 ppm in
roughly 70% of these samples (U.S. EPA, 2003).
One nPB supplier provided evidence that on the few occasions when
nPB concentrations from vapor degreasers were higher than the company's
recommended AEL of 25 ppm, users were able to reduce exposure easily
and inexpensively by changing work practices, such as reducing drafts
near the cleaning equipment (Kassem, 2003). The ability to meet the
workplace exposure limit depends on: (1) The features of the cleaning
equipment used, such as the presence of secondary cooling coils; and
(2) the work practices, such as avoiding drafts near cleaning equipment
and lifting cleaned pieces out slowly from the cleaning equipment.
Workplace controls could include, but are not limited to, the use of
the following: Covers on cold-cleaning and vapor degreasing equipment
when not in use; devices to limit air movement over the degreaser; and/
or a lip-vent exhaust system to capture vapors and vent them out of the
room. Training workers in industrial hygiene practices and in the
proper use of cold cleaning and vapor degreasing equipment, as well as
warning workers of the symptoms that may occur from over-exposure to
nPB, will also help reduce exposure. Therefore, we expect that users of
nPB in the solvent cleaning sector following typical industry practices
and using typical equipment for vapor degreasing will continue to meet
acceptable exposure levels and to use nPB safely without regulatory
requirements. This is the approach the SNAP program has taken with many
other solvents where users are readily able to meet workplace exposure
limit that will protect human health and there is no enforceable OSHA
PEL (e.g., HFC-365mfc, HFC-245fa, heptafluorocyclopentane, ketones,
alcohols, esters, hydrocarbons, etc.). Based on the available exposure
data and current industry practices, EPA believes that users of nPB as
an industrial solvent for metals cleaning, electronics cleaning, and
precision cleaning are likely to be exposed to concentrations of nPB
well below the proposed AEL of 25 ppm from the 2003 NPRM.
2. General Population Risks
In the 2003 NPRM, the Agency provided analyses demonstrating that
people living in the immediate vicinity of a facility using nPB in
spray adhesives would have exposures below the community exposure
guideline of 1 ppm (68 FR 33300-33301). The community exposure
guideline was derived considering both sperm motility and liver effects
in the WIL (2001) 2-generation study using EPA's reference
concentrations (RfC) guidelines (U.S. EPA, 1994b). Since the general
population would not be exposed in excess of the community exposure
guideline from a highly emissive application, the less emissive uses
such as metals, electronics, and precision cleaning would create
insignificant exposures (well below 1 ppm). Thus, we believe that
proper use of nPB in solvent cleaning would not pose measurable risks
to the general population.
V. How is EPA responding to comments on the June 2003 NPRM?
In this section, EPA responds to comments on the major issues in
the June 2003 NPRM. A complete response to comments is in docket EPA-
HQ-OAR-2002-0064.
A. EPA's Acceptability Decision
There was no consensus among commenters about whether EPA should
find nPB acceptable, acceptable subject to use conditions, or
unacceptable in the various end uses listed in the proposal. Some
commenters raised concerns about specific end uses, particularly
aerosols and adhesives. Others supported finding nPB acceptable in
solvents cleaning and in adhesives. We are not taking final action in
this rule with respect to nPB as a substitute in aerosols or adhesives.
We will respond to any comments regarding those end uses at the time we
take final action for aerosols and adhesives.
Comment: Several commenters supported EPA's proposed approval of
nPB under the SNAP program in various end uses. In contrast, two
commenters opposed EPA's proposed acceptability determination in all
end uses, including solvent cleaning, citing concerns about exposure
and the toxicity of nPB. Another commenter stated that applications
cited in the proposal (e.g., electronics and metals cleaning, label
removal and spray cleaning) are not suitable for use of nPB. This
commenter reasoned that if nPB provides unique performance
characteristics, its uses should be limited to non-emissive and low-
volume applications. A commenter from a company that markets nPB as a
chemical intermediate but not as a solvent, noted that his company
recognizes the health concerns associated with nPB, and thus his
company continues to prohibit the sale of nPB to customers with
dispersive uses. Another commenter stated that nPB is dangerous to the
ozone layer and workers and urged EPA to find a safe substitute.
Response: EPA believes nPB may be found acceptable under the SNAP
program only in those end uses where it has been shown to be used
safely, as compared with other substitutes that are currently or
potentially available. We find this to be the case for metals cleaning,
electronics cleaning, and precision cleaning.
Comment: Several commenters agreed with EPA's proposed approval for
nPB in metal cleaning, electronics cleaning, and precision cleaning end
uses. One specifically reported that his company's industrial hygiene
program for nPB-based solvents in metal and electronics cleaning has
conducted extensive air sampling, and that the majority of the samples
have shown values well below 25 ppm. This commenter also noted that, in
those few workplaces where higher levels were found, adoption of
recommended workplace ventilation and handling practices produced
acceptable subsequent sample values. Thus, this commenter believes that
exposures can be controlled to protective levels.
One commenter expressed concerns over the approval of nPB as
acceptable for use in solvent cleaning, maintaining that toxicity data
is insufficient to be convincing that long-term effects will not be a
concern. Two other commenters did not support EPA's proposal to find
nPB acceptable. One of the commenters concurred with EPA that exposures
from manual wipe cleaning will not be acceptable and that nPB should
not be used in such operations. Another commenter opposed EPA's
proposed acceptability determination for solvent cleaning, stating that
use of nPB in applications such as electronics and metals cleaning,
label removal, and spray cleaning is not appropriate.
Response: EPA agrees with those commenters who said nPB should be
acceptable for use in metal cleaning, electronics cleaning, and
precision cleaning. By our definition of the solvent cleaning sector,
such users are cleaning using industrial cleaning equipment. For an
organic solvent, this means a vapor degreaser or an automated cold
cleaning machine. Emissions from vapor degreasers can be controlled
both through improving equipment (increasing the freeboard, adding
cooling coils, or adding a lift that raises cleaned pieces slowly) and
through improved work practices (leaving the vicinity of the vapor
degreaser when done with work, tipping
[[Page 30152]]
work-pieces so they do not catch solvent, or lifting cleaned pieces out
slowly).
In solvent cleaning equipment, exposure data show that nPB can meet
an exposure level well below 25 ppm, even at levels of 5 ppm or less,
the majority of the time (U.S. EPA 2003; ICF, 2006a). Concentrations of
nPB emitted from industrial solvent cleaning equipment were measure to
be below 25 ppm in roughly 88% of more than 500 samples, below 18 ppm
in 81% of these samples, and at or below 5 ppm in 56% of these samples
(U.S. EPA, 2003). In cases where exposure levels are higher, there are
simple, cost-effective changes that can be made to reduce emissions
(Kassem, 2003). We agree that manual cleaning using nPB is
inappropriate, because of the difficulty of controlling emissions, but
manual cleaning is currently beyond the scope of the SNAP Program. EPA
plans to address spray cleaning using aerosols in a new proposal.
B. Toxicity
1. Health Endpoints
Comment: A number of commenters on the June 2003 NPRM suggested
that EPA should consider neurotoxicity as the endpoint in deriving the
AEL for nPB (Linnell, 2003; Werner, 2003; Rusch and Bernhard, 2003;
Rusch, 2003). In particular, they requested that EPA consider the study
conducted by Wang (2003) and epidemiological data on neurotoxic effects
of nPB.
Response: Recent data collected from occupational settings indicate
that severe, possibly irreversible, neurological effects may occur at
sustained concentrations of approximately 100 ppm or greater (Beck and
Caravati, 2003; Majersik, 2004; Majersik, 2005), with variability in
effects observed in different studies, although in most cases exposures
may have been much higher. Other studies with human data are discussed
above in section IV.E. Because of design and methodological
limitations, such as small numbers of subjects and limited exposure
information, none of the recent studies individually provides a
sufficient quantitative basis to derive an AEL.
In the study on rats by Wang et al. (2003), measurements found a
decrease in enzymes in the spinal cord and brain at 200, 400, and 800
ppm, but the animals displayed no physical or behavioral changes.
Because of the lack of physical symptoms or behavioral changes, EPA
does not believe that the decrease in enzyme levels in the central
nervous system are toxicologically relevant. Other studies examining
neurological effects of nPB showed those effects to be transient and
reversible at and above 200 ppm (Ichihara et al., 2000a). Exposures of
200 ppm and above for three weeks had no effect on memory, learning
function, or coordination of limbs (Honma, 2003); the effect of
spontaneous locomotor activity seen in this study at 50 ppm and above
was not considered adverse by the authors. In other studies,
neurological effects were absent after extended periods of exposure--
after 28 days of exposure at concentrations > 400 ppm (ClinTrials,
1997a) and after 90 days of exposure at concentrations up to 600 ppm
(ClinTrials, 1997b). Thus, although neurological effects have been
associated with nPB exposure, the data are currently insufficient to
quantify and set an AEL based on this endpoint. More recent data does
not change EPA's acceptability determination for solvent cleaning.
Comment: One commenter on the June 2003 NPRM requested that EPA
evaluate a study by Yamada et al (2003), a study published just prior
to the June 2003 NPRM.
Response: EPA reexamined Yamada et al., 2003 and re-evaluated the
literature (Ichihara et al., 1999, 2002, 2004a,b; Sekiguchi, 2002,
Yamada et al., 2003; WIL, 2001). Multiple benchmark analyses found a
statistically significant decrease in the number of estrous cycles and
increase in estrous cycle length associated with nPB exposure,
consistent with other reproductive endpoints, namely reductions in
sperm motility, decreased live litter size, and change in prostate
weight (ICF, 2002a; ICF, 2006a; Stelljes and Wood, 2004; TERA, 2004).
These more recent evaluations, which could lead to an HEC of 170 ppm
and an AEL of 17 ppm, do not change EPA's acceptability determination
for solvent cleaning, since the evidence supports the ability of users
in this end use to consistently meet such a level.
Comment: Some commenters stated that data from the F1 generation is
inappropriate for calculating occupational exposure, citing statements
from some toxicologists that use of effects on adult F1 generation
animals is inappropriate. They also stated that EPA has not required
this for other chemicals and that the resulting value is more
conservative than what is normal and appropriate for industrial
toxicology (Morford, 2003d and e; Ruckriegel, 2003). One commenter
claims that because EPA's review of nPB differed from EPA's review of
other SNAP alternatives, the process violates equal protection
(Morford, 2003d and e). Others stated that sperm motility effects on
the F1 generation are appropriate to consider (Risotto, 2003; Farr,
2003), particularly because of the potential for in utero effects and
because of the consistent presence of these reproductive effects in
both generations and at multiple levels.
Response: EPA is not finalizing a specific AEL for the purposes of
this final rule. EPA acknowledges that using data from the F1 offspring
generation may be conservative because the pups in the F1generation
were exposed to nPB between weaning and sexual maturity (WIL, 2001).
During occupational exposure, this period of exposure would not occur
because children under age 16 are not allowed to work in industrial
settings. However, EPA believes that because of the potential for in
utero effects that would only be seen in the offspring generation,
looking only at the F0 parental generation could underestimate the
adverse health impacts of a chemical. Therefore, it was appropriate for
us to consider effects seen in both the F0 parental generation and the
F1 offspring generation. Further, effects on sperm motility in the
parental and offspring generations are seen at levels generally
consistent with multiple reproductive effects seen in both generations
and both sexes exposed to nPB, such as estrous cycle length, lack of
estrous cycling, the number of estrous cycles in a given period of
time, fertility indices, and the number of live pup births (TERA, 2004;
ICF, 2006a; SLR International, 2001).
We also note that different substances have different toxicological
effects and those effects must be considered based on the best
scientific information and methodologies available. It is incorrect to
claim that such reviews, which focus on the effects of different
substances, resulted in disparate treatment of nPB \7\.
---------------------------------------------------------------------------
\7\ We interpret the commenter's use of the term ``equal
protection'' to mean that the commenter beleives that EPA has
performend a harsher review of nPB than it has for other substitutes
and not a claim that EPA has violated the 14\th\ Amendment of the
Constitution, which applies only to the states and not the Federal
Government.
---------------------------------------------------------------------------
2. Adjustments to Acceptable Exposure Level Based on Risk Management
Principles
In the 2003 NPRM, EPA derived 18 ppm as the starting point for an
acceptable exposure level based on reduced sperm motility in the
offspring generation of animals exposed to nPB (WIL, 2001). Following a
SNAP program principle that alternatives should be restricted only
where it is ``clearly more harmful to human health and the
[[Page 30153]]
environment than other alternatives,'' we noted that ``a slight
adjustment of the AEL may be warranted after applying judgment based on
the available data and after considering alternative derivations''(69
FR 33294, 33295). The Agency proposed an upward adjustment of the AEL
to 25 ppm based on principles of risk management, and based, among
other things, on a determination that 25 ppm was between the level
based on the most sensitive endpoint (sperm motility in the F1
offspring generation) and the second most sensitive endpoint (sperm
motility in the F0 parental generation). We stated further that ``18
ppm is a reasonable but possibly conservative starting point, and that
exposure to 25 ppm would not pose substantially greater risks, while
still falling below an upper bound on the occupation[al] exposure
limit.''
Comment: Commenters responded that: (1) The SNAP program does not
create a presumption in favor of substances that are already available
on the market, especially where other alternatives exist (Linnell,
2003; Werner, 2003); (2) EPA's AEL derivation of 18 ppm is not
conservative enough (Werner, 2003; Risotto, 2003) and further
adjustment upward further reduces protection; (3) the data do not
support adjusting the AEL upward (EPA-HQ-OAR-2002-0064-0003); (4) EPA
should first use the same methodology in establishing an AEL as for
other chemicals to ensure that the program's guiding principle in
comparing risks is not compromised (Werner, 2003); and (5) EPA should
reconsider whether industrial exposures consistently occur or can be
controlled at 25 ppm (Werner, 2003). No commenters specifically
supported adjusting the AEL upward.
Response: EPA is not finalizing a specific AEL for the purposes of
this final rule. In a separate proposed rulemaking for the aerosol,
adhesive and coatings end uses, we will be providing the public an
opportunity to comment on a range of exposure level values that are
comparable to the levels discussed in the June 2003 proposal (69 FR
33295) that the Agency would consider to be acceptable. Because we have
concluded that end users in the solvent sector are routinely able to
meet even the lowest exposure level we considered recommending (U.S.
EPA, 2003), we do not need to make a final determination as to the
appropriate level for purposes of this rulemaking.
3. Uncertainty Factors
According to EPA risk assessment guidance for RfC (EPA 1994a),
uncertainty factors of up to 10 may be applied to the ``human
equivalent concentrations (which accounts for worker exposure patterns
of 8 hours per day for 5 days a week), for each of the following
conditions:
(1) Data from animal studies are used to estimate effects on
humans;
(2) Data on healthy people or animals are adjusted to account for
variations in sensitivity among members of the human population (inter-
individual variability);
(3) Data from subchronic studies are used to provide estimates for
chronic exposure;
(4) Studies that only provide a LOAEL rather than a NOAEL or BMD;
or
(5) An incomplete database of toxicity information exists for the
chemical.
Comment: Some commenters on the June 2003 NPRM stated that EPA
should use an uncertainty factor of 1 or 2 to extrapolate from animals
to humans (Weiss Cohen, 2003), while others suggested uncertainty
factors of 2 or 3 for pharmacokinetics, or an overall uncertainty
factor of 10 for rat to human extrapolation because of a lack of
information on the metabolism and mode of action of nPB and because the
rat is an insensitive model for effects on male reproduction in humans
(Werner, 2003; Rusch and Bernhardt, 2003).
Response: EPA believes that two uncertainty factors are appropriate
for this database to account for (1) physiological differences between
humans and rats; and (2) variability within the working population. EPA
RfC guidelines state that an uncertainty factor of 10 may be used for
potential differences between study animals and humans. This factor of
10 consists in turn of two uncertainty factors of 3--the first to
account for differences in pharmacodynamics\8\ and the second to
account for differences in pharmacokinetics\9\ between the study animal
and humans. (The value of three is the square root of 10 rounded to one
digit, with 10 representing an order of magnitude [EPA,1994a, pp. 1-6,
4-73]. In practice, EPA uses the square root of 10 when there are two
or four uncertainty factors of 3, yielding a total uncertainty factor
of 10 or 100, and we use a value of 3 when multiplying by other
uncertainty factors.) In general, EPA's RfC guidelines state that for
the uncertainty factor extrapolating from animal to human data, ``Use
of a 3 is recommended with default dosimetric adjustments.'' (U.S. EPA,
1994b, p. 4-73). By EPA RfC guidelines (US EPA, 1994b), no adjustment
for differences in pharmacokinetics is necessary in this instance
because the blood/air partition coefficient \10\ for nPB in the human
(7.1) is less than in the rat (11.7), indicating that the delivered
dose of nPB into the bloodstream in rats is slightly higher than in
humans. EPA has seen no data to indicate that (1) the toxicity is not
directly related to the inhaled parent compound in the arterial blood,
or that (2) the critical metabolic pathways do not scale across
species, with respect to body weight, in the same way as the
ventilation rate. Consistent with Appendix J of EPA's RfC guidelines
for an inhaled compound that exerts its effects through the
bloodstream, EPA applies an uncertainty factor of 1 for
pharmacokinetics and an uncertainty factor of 3 for differences between
animals and humans.
---------------------------------------------------------------------------
\8\ Pharmacodynamics refers to the biochemical and physiological
effects of chemicals in the body and the mechanism of their actions.
\9\ Pharmacokinetics refers to the activity or fate of chemicals
in the body, including the processes of absorption, distribution,
localization in tissues, biotransformation, and excretion.
\10\ The blood/air partition coefficient is the ratio of a
chemical's concentration between blood and air when at equilibrium.
---------------------------------------------------------------------------
Recent studies provide additional data regarding metabolism of nPB
in rats and mice (RTI, 2005), but data on human metabolism are still
lacking. One analysis of these metabolic data suggested that mice are
less sensitive to the effects of nPB than rats and hypothesized that
humans would also be less sensitive than rats (Stelljes, 2005). This
analysis makes numerous assumptions about toxic nPB metabolites and
metabolic activation pathways that have not been confirmed by
experimental data. A review of this analysis is available in the public
docket (ICF, 2006c). Despite the difference in metabolic pathways for
nPB in mice and rats (RTI, 2005), EPA finds no significant species-
specific differences in toxicity exist between rats and mice at inhaled
concentrations <500 ppm for 13 weeks (NTP, 2003; ICF, 2006c). However,
these metabolic and subchronic inhalation studies conducted under the
National Toxicology Program did not specifically examine for
reproductive toxicity or nPB metabolism in target organs that control
reproductive function. In summary, there is little available data about
the metabolic activation or reactive metabolites responsible for
reproductive toxicity in rodents. Similarly, for nPB, there is little
information available about differences and similarities between
rodents and humans. Given this circumstance, EPA assumes, in the
absence of evidence to the contrary, that nPB toxicity is directly
related to the inhaled parent
[[Page 30154]]
compound in the arterial blood and that the critical metabolic pathways
scale across species in a manner similar to the ventilation rate (U.S.
EPA, 1994b). Therefore, the Agency applied an uncertainty factor of 1
to account for interspecies differences in pharmacokinetics.
Given the available data on the blood/air partition coefficient and
EPA RfC guidance in the absence of other information, EPA is applying
the same rationale used for other compounds reviewed under EPA's SNAP
program with a comparable amount of data where an uncertainty factor of
1 for pharmacokinetics was applied. To account for uncertainty in
pharmacodynamics of nPB, EPA is applying the default uncertainty factor
of 3. This follows the procedures in EPA's RfC guidelines for
situations where there are no data to compare pharmacodynamics in rats
versus humans (U.S. EPA, 1994b). Recently published data on humans and
rodents do not decrease the uncertainty regarding the pharmacodynamics
of nPB; therefore, modification of the uncertainty factor of 3 for
differences between species was not justified.
Comment: One commenter stated that EPA did not cite any data that
describes the size, condition, or existence of a subpopulation of men
especially sensitive to the effects of nPB. In addition, this commenter
asserted that sensitive populations are not traditionally considered
when deriving an OEL, and that EPA has never mentioned a concern with
sensitive subpopulations in previous SNAP reviews. Another commenter
said that there is no evidence to support the assertion that nPB
exposure below a 100 ppm average will further reduce sperm count or
that the removal of nPB exposure will improve sperm count.
Response: EPA disagrees with the comments. There are preexisting
reproductive conditions as well as significant variability in fertility
among otherwise healthy adults in the workplace. Both male and female
reproduction have been shown to be adversely affected by aging, with
effects on the ovarian cycle and on sperm motility as major factors
changing with increasing age for women and men, respectively (Dunson et
al., 2002). Adding damage from other factors, such as smoking or
occupational exposure to chemicals such as nPB, therefore, can
potentially harm an individual's ability to reproduce further (Dunson,
et al. 2002). EPA did not issue a proposal based on sperm count, so
that comment is not relevant to this rule. In addition, we note that
EPA has used uncertainty factors in the past to protect sensitive
subpopulations on other chemicals reviewed under the SNAP program
(e.g., trifluoroiodomethane at 60 FR 31092, 61 FR 25585 and
IoGasTM Sterilant Blends at 69 FR 58903). For deriving AELs
from health endpoints such as liver effects and neurotoxicity, the SNAP
program typically has assigned an uncertainty factor of 1 for sensitive
subpopulations because we assume that individuals who are especially
susceptible to these effects will have greater difficulty working than
most people. However, there is no connection between the ability to
reproduce and the ability to work in the industrial sectors discussed
in this rule. Thus, we find it appropriate to require an uncertainty
factor greater than 1 for reproductive effects for variability within
the working population.
Comment: Some commenters said that an uncertainty factor of 1 is
appropriate for variability within the working population because
sensitive subpopulations will not be present in the working population
(Stelljes, 2003, Morford, 2003e). Other commenters stated that there
will be very little difference in variability between the worker
population and the general population and that it is unclear why EPA
selected an uncertainty factor of 3 instead of 10 (Werner, 2003).
Commenters suggested uncertainty factors for variability in the working
population of 1, 2, and 5 (Stelljes, 2003, Weiss Cohen, 2003, Werner,
2003).
Response: EPA disagrees with the commenters. EPA's RfC guidelines
recommend an uncertainty factor of 10 to account for intraspecies
variability within the general population. However, in developing an
AEL, EPA's focus is on worker exposure, which excludes some
particularly vulnerable populations, such as children, most
adolescents, and the elderly. Thus, we believe that a full uncertainty
factor of 10, as for the general population, may be higher than
necessary to protect workers. Certain individuals in the general
population but not in the working population that might be particularly
vulnerable would include children and adolescents under age 16 and
individuals with immune deficiency disorders. However, because of
variability in reproductive function due to factors present among
workers, such as aging, smoking, and sexually transmitted disease
(Dunson et al., 2002), and because there is no screening of workers
that would make workers more likely to have healthy reproductive
systems than non-workers of the same age, we believe than an
uncertainty factor of 1 is not sufficiently protective. Under EPA
guidelines, 3 is a default value for an uncertainty factor where there
is indication that a value less than an order of magnitude (10) but
greater than one is appropriate, and where the available data are not
sufficiently quantified to select a specific value.
4. Other Analyses of nPB's Toxicity
Comment: One commenter stated that documents by Drs. Doull, Rozman,
Stelljes, Murray, Rodricks, and the KS Crump Group were not
acknowledged (Morford, 2003d,e, and f). Another commenter requested
that EPA take into account the scientific presentations presented by
Drs. Doull, Rozman and Stelljes and mentions a review by Dr. Rodricks
(Weiss Cohen, 2003).
Response: EPA specifically mentioned and responded to the
occupational exposure limit recommendations from Drs. Rozman, Doull,
and Stelljes in the preamble to the June 2003 NPRM at 68 FR 33298-
33299. In addition, EPA included more detailed written responses to
these derivations and the evaluation by Dr. Rodricks in the online
docket prior to proposal (EPA-HQ-OAR-2002-0064-0017, -0018, and -0019).
Here are abbreviated responses to the various documents cited by the
commenter:
Drs. Doull and Rozman's letter dated August 24, 2001,
stating that a two-generational reproductive study is not appropriate
(Docket A-2001-07, item II-D-26)--Drs. Doull and Rozman do not provide
a rationale for their statement. Their statement is in conflict with
their AEL derivation, in which they consider use of the F1 generation
of the WIL Laboratories two-generation study. As discussed above in
section V.B.1, EPA believes that data from a two-generation
reproductive study are appropriate in developing a guideline for the
workplace in order to assure that workers and their children are
protected from any adverse health effects of workplace exposure,
including exposure in utero. We acknowledge that this value may be more
conservative than considering data only from the parental generation.
Drs. Doull and Rozman's critique of ICF's AEL derivation
(II-D-41b)--Drs. Doull and Rozman's primary stated reason for rejecting
ICF Consulting's evaluation is that it does not reflect their own AEL
derivation. They reiterate that they find neurotoxicity to be the
appropriate basis for an AEL without addressing the reasons that ICF's
derivation provides for finding reproductive toxicity to be of greater
concern than neurotoxicity. We disagree with Doull and Rozman's
conclusion that neurotoxicity is the more
[[Page 30155]]
appropriate endpoint for several reasons: (1) The human data are
insufficient to draw conclusions because of a small number of subjects,
limited exposure information, and lack of statistical significance; (2)
the animal data on neurotoxicity are inconsistent and equivocal
concerning the level at which nervous system effects occur, and they
indicate that neurotoxic effects may be reversible; and (3)
neurotoxicity is a less sensitive endpoint than reproductive effects.
However, if we had used neurotoxicity as the endpoint for an AEL, we
would have reached the same acceptability determination for solvent
cleaning.
The basis of EPA's June 2003 NPRM is different from either one of
these documents because it uses a different endpoint from Doull and
Rozman's derivation (2001) and an uncertainty factor of 3 instead of 2
to 3 for variability within the working population (Doull and Rozman,
2001; ICF, 2002a). According to EPA guidance on establishing
uncertainty factors, if a uncertainty factor is between 1 and 10 and
the data are not sufficient to quantify the uncertainty between those
values, the default uncertainty factor to be used is 3 (U.S. EPA,
1994b).
Drs. Rozman and Doull's derivation of an AEL (II-D-63)--
EPA discussed our evaluation of this document at length in the preamble
of the June 2003 NPRM at 68 FR 33298. In particular, we disagree with
Rozman and Doull's selection of the most sensitive endpoint. Rozman and
Doull concluded that reproductive toxicity should not be considered the
most sensitive endpoint, stating that a National Institute for
Occupational Safety and Health (NIOSH) evaluation found that no human
beings at a facility using nPB-based adhesives experienced reproductive
health effects from the nPB. However, the NIOSH study in fact concluded
that the survey questions would not be sufficient to determine if there
were reproductive health effects, which is significantly different from
saying that there was no health effect. The expert panel for the CERHR
looked at the NIOSH report and a wide range of human and animal studies
on nPB; in contrast to Rozman and Doull, the expert panel concluded
that there was insufficient information on reproductive effects of nPB
on humans and that the results of tests on animals were considered
appropriate for evaluating potential reproductive health effects on
humans.
Further, EPA disagrees with the specific AEL value of 60 to 90 ppm
that Rozman and Doull derived. They used data on headaches from a draft
NIOSH survey, selecting an endpoint of 190 ppm. However, the data in
the final survey were not sufficient to detect any dose-response with
any statistical significance (Custom Products HHE, II-A-49). Further,
more recent studies on human exposure to nPB have found neurotoxic
effects occurring at levels at least as low as 86 ppm, and possibly
lower than 60 ppm (Ichihara 2004a, Beck and Caravati 2003). These data
would indicate that an AEL of 60 to 90 ppm is not sufficiently
protective against neurotoxic effects. Drs. Rozman and Doull themselves
now suggest that an AEL of 25 ppm may be more appropriate for
protecting against neurotoxic effects (Rozman and Doull, 2005).
Dr. Rodricks' AEL derivation and comments on ICF's
derivation (II-D-65)--EPA reviewed Rodricks (2002) in developing its
June 2003 NPRM, although the study was not explicitly mentioned in that
preamble. Rodricks (2002) suggests an AEL of 60 to 88 ppm for nPB,
based on male reproductive effects. Dr. Rodricks says that the most
sensitive endpoint that is relevant for occupational exposure is data
from the parent generation of the two-generation reproductive study.
Dr. Rodricks suggests that an uncertainty factor of only 1 to 2 is
necessary for animal to human extrapolation because one should consider
animals and workers of average sensitivity; although such an argument
presumably could be made for any chemical used in the workplace, EPA
has not seen other AEL derivations that use this approach. Dr. Rodricks
appears to agree with ICF that an uncertainty factor for variability in
reproductive function in the human population is reasonable, although
he suggests a factor of 2 instead of the range of 2 to 3 in ICF's
derivation. Dr. Rodricks and colleagues previously recommended an AEL
for nPB of less than 10 ppm, and at that time suggested an uncertainty
factor of 10 for variability in reproductive function in the human
population (A-91-42, X-B-53). We discussed above the use of data from
both the F0 and F1 generations and the use of an uncertainty factor of
3 for variability within the working population.
Dr. Stelljes's critique of ICF's AEL derivation (II-D-
41a)--Dr. Stelljes states that ICF should have used data from the
parent generation rather than from the offspring generation because
``data from F1 animals is not directly applicable to a workplace
exposure setting because both parents would not be exposed to nPB on a
daily basis over the reproductive cycle, and also have their offspring
exposed daily from weaning.'' EPA disagrees in part with Dr. Stelljes's
reasoning. Data from F0 animals may not be sufficiently protective
because effects on the F0 animals will not reflect effects of in utero
exposure. However, we agree that exposure during weaning is not
reflective of workplace exposure, and thus, data from F1 animals may be
conservative. EPA proposed 25 ppm instead of 18 ppm in part to take
this conservatism into account.
Dr. Stelljes's (SLR International's) AEL derivation (II-D-
13)--EPA discussed this AEL derivation at length in the preamble to the
proposed rule at 68 FR 33298. We agreed with Dr. Stelljes's BMD
modeling and his selection of reduced sperm motility in the F1
offspring generation of the WIL Laboratories study as the most
sensitive endpoint. However, we disagree with Dr. Stelljes's selection
of uncertainty factors. There is no information showing that human sex
cells are less sensitive to nPB than rat sex cells, and there is
considerable evidence that human males have less reproductive capacity
than male rats (U.S. EPA, 1996). Therefore, it is appropriate to add an
uncertainty factor of at least 3 to account for differences between
rats and humans. Further, Stelljes dismisses the use of an uncertainty
factor for differences within the human population. Although we agree
that children and the elderly would not be present in the workplace as
sensitive subpopulations, there certainly is variability in the
reproductive abilities of different working-age people that would have
no impact on the individual's ability to be hired or to work;
therefore, EPA expects there is some variability in the susceptibility
of working individuals to the effects of reproductive toxicants. EPA
believes that male reproductive capacity is very susceptible to
chemical insult (U.S. EPA, 1996).
Dr. Murray's opinion on parent and offspring generations
(II-D-58)--Dr. Murray says that because the offspring generation will
not yet have developed sperm while in utero, it is more appropriate to
use data from the parent generation of the two-generation study.
However, Dr. Murray does not address the possibility that nPB exposure
during pregnancy could influence the production of hormones that
eventually would result in sperm production. Further, Dr. Murray's
response does not address potential effects on ova, which would be
present while a fetus is still in its mother's womb.
Report on uncertainty factors used by ACGIH from K.S.
Crump Group (IV-D-26/OAR-2002-0064-0047 and -48)--This report concluded
that EPA's
[[Page 30156]]
approach to selecting uncertainty factors for use in risk assessment
was more transparent, with justification for each value selected, and
was more consistent than the values apparently used by the ACGIH in
deriving TLVs. EPA agrees with these conclusions.
Comment: A commenter states that ``an uncertainty factor of 10 is
NOT `generally' used to derive occupational exposure limits and that in
fact, uncertainty factors of 3 or less or more commonly used,'' citing
the K. S. Crump Group's report.
Response: In the case of the TLV that ACGIH established for nPB,
ACGIH appears to set an AEL that is a factor of 10 lower than the
endpoint cited as lowest (100 ppm for effects on pup weight) (ACGIH,
2005). Thus, ACGIH has used an approach for nPB consistent with the
total uncertainty factor of 10 assigned by EPA.
5. Overall Stringency of the Acceptable Exposure Limit
Comment: Some commenters supported the proposed AEL of 25 ppm,
stating that it was derived using appropriate conservative and cautious
scientific processes. Other commenters said that the proposed AEL of 25
ppm was too high, citing uncertainties in the data, the
inappropriateness of adjusting the AEL upward from 18 ppm, reports of
health effects on humans, and a need for higher uncertainty factors.
Other commenters said that the proposed AEL of 25 ppm was too low,
citing higher AELs derived by Drs. Stelljes, Doull, Rozman, and
Rodricks, NIOSH studies, and a need for lower uncertainty factors.
Commenters suggested alternate AEL values ranging from 1 ppm to 156
ppm.
Response: In this final rule, EPA is not recommending an acceptable
exposure limit. We have based our determination of acceptability by
comparing measured exposure levels from workers using nPB in solvent
cleaning to exposure levels discussed by EPA in the proposal (see
section IV.E). At the levels discussed in the NRPM or higher, we find
nPB acceptable for solvent cleaning. After considering the available
scientific studies on toxicity, exposure data, and alternative
derivations of the acceptable exposure limit, we find that the exposure
levels discussed in 2003 provide sufficient protection for human health
and are consistent with EPA's derivations of AELs for other chemicals
reviewed under the SNAP program and EPA guidance for risk assessment.
6. Skin Absorption
In the June 2003 NPRM, EPA discussed listing nPB with a skin
notation, and proposed that this was not necessary (68 FR 33295).
Comment: Several commenters on the June 2003 proposal stated that a
skin notation for nPB is appropriate, while another commenter agreed
with EPA's proposal that no skin notation was necessary (Smith, 2003;
HESIS, 2003; Werner, 2003, Weiss Cohen, 2003). One commenter said that
EPA should require manufacturers, distributors, and marketers of nPB-
containing products to communicate such information on the Material
Safety Data Sheets (MSDS) and the product label.
Response: We agree with the commenter that said a skin notation is
not necessary. However, today's decision includes a recommendation for
users to wear protective clothing and flexible laminate gloves when
using nPB to address the concerns about dermal exposure.
Rat studies indicate that dermal exposure to nPB results in neither
appreciable absorption through the skin (RTI, 2005) nor systemic
toxicity (Elf Atochem, 1995). Unlike methyl chloride and dichlorvos,
which are absorbed through the skin and could contribute to systemic
toxicity (ACGIH, 1991), EPA is not including a skin notation for nPB in
the information provided to users associated with this rulemaking
because of the relatively low level of absorption. The ACGIH provides
no skin notation in its TLV documentation for several solvents,
including nPB (ACGIH, 2005), methylene chloride, and perchloroethylene,
and there is no evidence that absorption through the skin is greater
for nPB than for the other halogenated compounds. The TLV documentation
for nPB states, ``There is no basis for a skin notation because the
dermal LD50 of 1-BP was >2 g/kg.'' Further, including a statement
giving advice about how to reduce skin exposure in the ``Further
Information'' column of listings is likely to be more informative to
workers than a skin notation.
Given the possibility that some nPB can be absorbed through the
skin in humans, and that the solvent can irritate the skin, EPA
encourages users to wear protective clothing and flexible laminate
gloves when using nPB and encourages manufacturers, distributors, and
marketers of nPB-containing products to include such precautions in
their MSDSs. EPA believes that our regulatory authority for the SNAP
program is over the substitution (use) of ozone-depleting substances,
and thus, we do not believe we have sufficient authority to regulate
the manufacturers, distributors and marketers of nPB.
7. Iso-Propyl Bromide Limit
In the June 2003 proposed rule, we proposed as a use condition that
nPB formulations contain no more than 0.05% isopropyl bromide (iPB)
\11\ by weight because of potential health effects associated with this
isomer (68 FR 33301-33302).
---------------------------------------------------------------------------
\11\ iPB is also referred to as 2-bromopropane, 2-propyl
bromide, or 2-BP. Its CAS registry number is 75-26-3.
---------------------------------------------------------------------------
Comment: Two commenters said that 0.05% iPB is an appropriate and
achievable limit. (Smith, 2003; Weiss Cohen, 2003). One of these
commenters stated that industry test studies showed that lower limits
were neither toxicologically justified nor economical. Another
commenter opposed the implementation of the proposed use restriction,
stating that it places an undue legal burden on end users, rather than
the manufacturers of raw materials, and would not benefit worker
safety. This commenter also stated that this is the only instance that
SNAP has regulated residual contaminants. This commenter also suggested
that EPA defer to an AEL of 1 ppm for iPB established by the government
of Korea and the Japan Society for Occupational Health. Moreover, this
commenter said that the difference between the acceptable iPB exposure
determined by EPA and that determined by ASTM-D6368-00 is very small
and, thus, EPA's proposed regulation does not add any value to existing
standards. Finally, this commenter noted that epidemiological data
found no adverse effect on human workers exposed to 110 ppm of iPB
(Ichihara, specific study not identified by the commenter). (Morford,
2003g and h).
Response: We agree that industry has achieved this contamination
limit for several years without regulation. We also agree that the
concentration of iPB likely to be breathed in by workers would be below
1 ppm even if workers were exposed to concentrations of nPB at 100 ppm
or more, provided that the iPB content meets the ASTM-D6368-00 standard
for nPB used in vapor degreasing. Further, even if iPB were present in
nPB formulations in concentrations as high as 1%, if industry meets the
AEL for nPB proposed in 2003 of 25 ppm, or lower, exposures still would
be at most 0.25 ppm. This is below the level of 1 ppm established by
the Korean government and by the Japan Society for Occupational Health
(Morford, 2003h). Therefore, we are not adopting a use condition for
iPB for the solvent cleaning end uses.
[[Page 30157]]
8. Short-Term Exposure Limit (STEL)
In the June 2003 NPRM, EPA recommended a short-term exposure limit
of 75 ppm (three times the AEL).
Comment: One commenter noted that there was no indication in the
various applications as to how the exposures from those operations
compared to the EPA recommendation for a STEL at 75 ppm. This commenter
asserted that the potential for exceeding the STEL in solvent cleaning
applications appears high and should, therefore, be investigated by
EPA. This commenter also stated that, depending on the results of this
investigation, EPA may choose to find nPB unacceptable in metals
cleaning or restrict its use to where ventilation is employed and/or
personal protective equipment is worn.
Response: EPA disagrees that it is necessary to use a short-term
exposure limit in determining the acceptability of nPB in solvent
cleaning. Acute, short-term exposures of nPB are not of significant
health concern, so long as long-term exposures are below the 8-hour TWA
limit (ERG, 2004). EPA provided the STEL recommendation in the June
2003 proposal to give guidance to the user community, consistent with
the following recommendation of the American Conference of Governmental
Industrial Hygienists (ACGIH): ``Excursions in worker exposure levels
may exceed 3 times the [threshold limit value] TLV-TWA for no more than
a total of 30 minutes during a workday'' (ACGIH 1999). We note that
when the ACGIH developed a TLV for nPB, they said there were no data to
support a short-term exposure limit (ACGIH, 2005).
C. Ozone Depletion Potential
We proposed that, since the ODP of nPB in the continental U.S. is
only 0.013 to 0.018 relative to an ODP of 0.8 for CFC-113, 0.1 for
methyl chloroform, and 0.1 for HCFC-141b, nPB should not be found
unacceptable because of its ODP (68 FR 33303). The Agency recognized
that nPB's ODP could be much higher in tropical regions, as high as
0.071 to 0.100, but since EPA is regulating nPB used in the U.S., we
made our decision based on the ODP in the continental U.S.
Comment: One commenter on the June 2003 NPRM provided information
(Wuebbles, 2002) and stated that ``even if the entire amount of nPB
produced in 2002 was emitted across North American, European and Asian
latitudes, the resulting effects on ozone depletion would be too small
to measure.'' The same commenter said that the effects on ozone would
only be larger if all emissions were to occur in the equatorial region.
(Morford, 2003f).
Response: EPA agrees that, based on the current usage of nPB and
its ODP in the U.S., there is not a significant impact on the ozone
layer.
Comment: Comments on the June 2003 NPRM expressed concern that
other countries, particularly those in equatorial regions, might assume
that nPB does not pose a danger to the stratospheric ozone layer if the
U.S. EPA's SNAP program finds nPB acceptable (Linnell, 2003;
Steminiski, 2003).
Response: Because the ODP for nPB is higher when used in the
tropics (see footnote 3 above in section IV.2), we recognize the
concerns raised by these commenters. However, EPA is regulating use in
the U.S. and cannot dictate actions taken by other countries. For
example, other countries could choose to continue to use nPB even if
EPA were to find it unacceptable in the U.S. We believe the more
appropriate forum to address this concern is through the Parties to the
Montreal Protocol.
At the most recent Meeting of the Parties to the Montreal Protocol,
the Parties made the following decision with regard to n-propyl
bromide, in order to ``allow Parties to consider further steps
regarding n-propyl bromide, in the light of available alternatives''
(Decision XVIII/11):
1. To request the Scientific Assessment Panel to update existing
information on the ozone depletion potential of n-propyl bromide,
including ozone depleting potential depending on the location of the
emissions and the season in the hemisphere at that location;
2. To request the Technology and Economic Assessment Panel to
continue its assessment of global emissions of n-propyl bromide, * * *
paying particular attention to:
(a) Obtaining more complete data on production and uses of n-propyl
bromide as well as emissions of n-propyl bromide from those sources;
(b) Providing further information on the technological and
economical availability of alternatives for the different use
categories of n-propyl bromide and information on the toxicity of and
regulations on the substitutes for n-propyl bromide;
(c) Presenting information on the ozone depletion potential of the
substances for which n-propyl bromide is used as a replacement;
3. To request that the Technology and Economic Assessment Panel
prepare a report on the assessment referred to in paragraph 1 in time
for the twenty-seventh meeting of the Open-ended Working Group for the
consideration of the Nineteenth Meeting of the Parties. (MOP 18, 2006)
D. Other Environmental Impacts
With respect to environmental effects other than ozone depletion
potential, we stated in the June 2003 NPRM that users should observe
existing Federal, state, and local regulations such as those under the
Resource Conservation and Recovery Act or those for compliance with the
National Ambient Air Quality Standards (68 FR 33304).
Comment: Commenters stated that, until the safety of nPB has been
demonstrated conclusively, more stringent controls are necessary to
protect the public and the environment. In particular, these commenters
said that the potential for cross-media impacts was not given adequate
consideration in the proposed rule. They also stated that EPA did not
address the potential for nPB to bioaccumulate in the environment or
its impact on sensitive species. One commenter said that he thought it
was appropriate to ensure that nPB be kept out of wastewater, and an
independent contractor also mentioned concerns about water pollution.
Another commenter said that nPB hydrolyzes more quickly than the
chlorinated solvents, and so would have less impact on water quality.
Currently, the representative's company recommends that spent solvents
be incinerated, and offers free pickup and disposal of spent solvent to
its customers.
Response: EPA agrees that it should not be standard practice to
dispose of spent nPB in water, and that nPB should be kept out of
wastewater to the extent possible. This may be achieved by recycling or
through incineration. These also are good practices with other spent
halogenated solvents, whether or not they are specifically listed as
hazardous wastes.
EPA's PBT (persistence/bioaccumulation/toxicity) profiler tool
suggested that, based on its structure, nPB would not be considered
persistent in water or soil and that nPB would have a low tendency to
bioaccumulate (8.3, where 1000 is considered bioaccumulative and
greater than 5000 is considered very bioaccumulative). Further, the
calculated bioconcentration factor for nPB is only in the range of 18
to 23 (HSDB, 2004; ICF, 2004a). Under EPA's criteria for listing
chemicals on the Toxics Release Inventory, this would not be a level of
concern (ICF 2004a, EPA 1992). Therefore, we conclude further testing
for bioaccumulation of this chemical is not needed before rendering a
decision for
[[Page 30158]]
use of nPB in the solvent cleaning sector.
Currently, the estimated amount of nPB used in the U.S. in SNAP
sectors is on the order of 10 to 12 million pounds per year, which
corresponds to roughly 1% of the organic solvent cleaning market, a
relatively small amount. It is unlikely that very large amounts of nPB
will enter and remain in the nation's water supply, because:
nPB tends to evaporate quickly, with a calculated half-
life of 3.4 hours in a river or 4.4 days in a lake due to
volatilization.
nPB hydrolyzes readily, with a measured hydrolysis half-
life of 26 days at 25[deg] C and pH 7.
If released to the atmosphere, nPB will exist solely in
the vapor phase based on its vapor pressure of 110.8 mm Hg. Thus, it is
unlikely to be redeposited in rainwater in significant amounts. (PBT
Profiler, 2007; ICF, 2004a)
Further, because nPB is short-lived compared to ODS and many ODS
substitutes, it is unlikely that nPB will create a substantially
greater impact than other acceptable cleaning solvents and than the ODS
it replaces. EPA is required by the Clean Air Act to consider whether a
replacement for an ODS is more harmful, overall, to human health and
the environment than other available or potentially available
substitutes. The available information shows that nPB will not be more
hazardous than other available, acceptable solvents if it pollutes
water or soil.
E. Flammability
In the June 2003 NPRM, we proposed that nPB should not be
restricted or found unacceptable because of flammability (68 FR 33303).
EPA specifically requested data concerning the flashpoint of pure nPB,
including the test method used to provide the data.
Comment: Several manufacturers of nPB and nPB-based solvents and an
independent contractor stated that nPB has no flash point under a
number of accepted consensus standards for flash point. In support of
these statements, the manufacturers of nPB and nPB-based solvents
provided flash point test data from a number of different test methods
(ASTM D 92 open cup, ASTM D56 Tag closed cup, and ASTM D93 Pensky-
Martens closed cup).
Response: EPA agrees. The test results provided by the commenters
indicates that nPB has no flash point using a number of standard test
methods, including ASTM D 92 open cup, ASTM D56 Tag closed cup, and
ASTM D93 Pensky-Martens closed cup. Based on these data, we find that
nPB is not flammable under standard test conditions. EPA concludes that
nPB should not be considered unacceptable on the basis of flammability
risks.
F. Legal Authority to Set Exposure Limits
Comment: Two commenters stated that EPA has no jurisdiction to
develop any AEL designed to be applicable to a workplace environment,
and that this right belongs to OSHA.
Response: As an initial matter, EPA notes that it has not
established an AEL applicable to the workplace in this rule. Rather,
EPA reviewed the available information to determine what a safe
workplace exposure might be in order to determine whether use of nPB in
the solvent cleaning sector poses substantially more risk than use of
other available substitutes. The analysis performed by EPA imposes no
binding obligation on anyone, particularly in this case where EPA
determined that nPB is acceptable for use in the solvent cleaning
sector.
Although the Occupational Safety and Health Act (OSH Act) gives the
Occupational Safety and Health Administration (OSHA) authority to issue
a rule setting or revising an occupational safety or health standard
(29 U.S.C. 655(b)), it does not prohibit other Federal agencies from
reviewing the safe level of exposure under other statutes that require
consideration of the human health and environmental effects of a
substance. Conversely, although section 4(b)(1) of the OSH Act
prohibits OSHA from regulating a working condition addressed by another
federal agency's regulations affecting occupational safety or health,
this provision is overridden with respect to EPA's exercise of
authority under the Clean Air Act by 42 U.S.C. 7610. That provision
states: ``(a) Except as provided in subsection (b) of this section,
this chapter shall not be construed as superseding or limiting the
authorities and responsibilities, under any other provision of law, of
the Administrator or any other Federal officer, department, or
agency.''
Section 612 of the Clean Air Act expressly recognizes that some
substitutes for ODS may pose more risk to human health and the
environment than others and expressly requires EPA to prohibit use of
substitutes that pose more risk than other substitutes that are
currently or potentially available. Thus, in evaluating whether a
substitute should be found acceptable, we must compare the risks to
human health and the environment of that substitute to the risks
associated with other substitutes that are currently or potentially
available.
Our long-standing interpretation is that worker safety is a factor
we consider in determining whether a substitute poses significantly
greater risk than other available substitutes. In the original SNAP
rule, we promulgated the criteria we would review for purposes of
determining whether a substitute posed more risk than other available
substitutes. Specifically, 40 CFR 82.178(a) specifies the information
we require as part of a SNAP application and 40 CFR 82.180(a)(7)
identifies the criteria for review. Notably, we require submitters to
provide information regarding the exposure data (40 CFR 82.178(a)(10))
and we identify ``occupational risks'' as one of the criteria for
review (40 CFR 82.180(a)(7)(iv)). In the preamble of the original SNAP
rule, we said that we would use any available OSHA PELs, EPA inhalation
reference concentrations, or EPA cancer slope factor data for a
substitute together with exposure data to explore possible concerns
with toxicity (March 18, 1994; 59 FR 13066). We have reviewed
substitutes based on existing OSHA PELs, where available, and, where
not available, based on our own assessment of what level is safe for
workers. (See e.g., March 18, 1994, 59 FR 13044; Sept. 5, 1996, 61 FR
47012; June 8, 1999, 64 FR 30410; June 19, 2000, 65 FR 37900; December
18, 2000, 65 FR 78977; March 22, 2002, 67 FR 13272; August 21, 2003, 68
FR 50533). In making our own assessment, we review any existing
recommended exposure guidelines and available scientific studies and
use EPA's risk assessment guidelines (e.g., U.S. EPA, 1994b).
In the case of EPA's evaluation of nPB, there is no final OSHA PEL
for EPA to use in evaluating workplace exposure risks. There is a wide
variability in the workplace exposure guidelines recommended by
manufacturers of nPB-based products, ranging from 5 ppm to 100 ppm,
thus providing no definitive value for evaluating the human health
risks of workplace exposure. The ACGIH has recently established a TLV
for nPB of 10 ppm; however, as discussed above in section IV.E, EPA has
concerns about the scientific basis for this TLV. As provided in the
original SNAP rule, in the absence of a definitive workplace exposure
limit set by OSHA, we evaluated the available information to establish
our own health-based criteria for evaluating nPB's human health risks
to workers.
[[Page 30159]]
Comment: A commenter said that EPA's authority for the SNAP program
is under section 615 of the Clean Air Act and that the SNAP program
only has authority to take action based on effects on the stratosphere.
Specifically, the commenter claims section 615 of the CAA limits EPA's
authority under title VI to regulating for purposes of protecting the
stratospheric ozone layer. Citing section 618, the commenter also
contends that section 618 identified SNAP requirements as
``requirements for the control and abatement of air pollution'' and
cites the CAA and EPA policy documents as identifying ambient air as
air external to buildings. The commenter also notes that title VI was
intended to implement the Montreal Protocol and that it replaced former
Part B. The commenter cites legislative history from the enactment of
Part B that indicated EPA's authority under Part B was not intended to
pre-empt authority of other agencies to take action with respect to
hazards in their areas of jurisdiction and that EPA's authority under
Part B was only to fill regulatory gaps and not to supersede existing
authority of other agencies. With respect to the legislative history of
the 1990 Amendments, the commenter argues that there is no suggestion
that ``EPA has authority to set workplace worker-exposure standards.''
The commenter also cites legislative history from the Toxic Substances
Control Act in which Congress indicated EPA's authority under that
statute does not extend to setting workplace standards.
Response: While many provisions in title VI address the regulation
of substances that deplete the stratospheric ozone layer, section 612
which governs the SNAP program is broader. The purpose of Section 612
is to review substitutes for ODS and Section 612 of the Clean Air Act
clearly requires EPA to consider both the environmental effects as well
as human health, which includes both the health of the general
population and workers. EPA believes there is no doubt that the
statutory language requires EPA to consider effects beyond those on the
stratospheric ozone layer. In addition, the legislative history makes
clear that this language is to be interpreted broadly. Specifically,
the report of House Debate on the Clean Air Act Amendments provides
``the Administrator shall base risk estimates on the total
environmental risk (toxicity, flammability, atmospheric, etc.) that is
perceived to exist, not just the risk as it relates to ozone
depletion.'' House Debate on the Clean Air Act Amendments of 1990
Conference Report, S-Prt 103-38 at 1337. The legislative history cited
by the commenter is not pertinent. The legislative history for Part B
of Title I of the Act is not relevant because that section was repealed
in 1990. Public Law 101-549, section 601. Nor is the legislative
history for other statutes, such as TSCA, relevant for determining what
authority Congress granted to EPA under the CAA.
The commenter incorrectly states that sections 615 and 618 of the
CAA place limits on EPA's authority under section 612 of the Act. These
provisions expand, rather than restrict, the Administrator's authority.
Section 615 is a separate provision of the statute and provides general
authority for the Administrator to regulate for purposes of addressing
adverse effects to the stratosphere. This provision does not explicitly
or implicitly purport to limit the Administrator's authority under
other provisions of the Act. Rather, it is a general provision
authorizing the Administrator to regulate for protecting against
adverse effects to the stratospheric ozone layer.
With respect to section 618, we first note that the commenter
appears to equate the stratospheric ozone layer with ``ambient air.''
In fact, they are two different things. Ambient air is defined as
``that portion of the atmosphere, external to buildings, to which the
general public has access.'' 40 CFR 50.1(e). The stratospheric level
generally extends from 10 to 50 kilometers above the earth and is not
considered air to which the public has access. [See http://www.epa.gov/ozone/defns.html]. The definition of ``air pollutant'' under the CAA is
defined in terms of substances emitted to the ``ambient air.'' The
purpose of section 618 is to make clear that for purposes of sections
116 (retention of state authority) and 118 (control of pollution from
federal facilities), the provisions in Title VI governing protection of
the stratospheric ozone layer shall be treated the same as if they were
for the purpose of controlling and abating ``air pollution'' (i.e.,
pollution to the ambient air). Again, this is not for the purpose of
restricting the Administrator's authority under any provision of the
Act. Rather, it is for the purpose of extending the protections of
Title VI to programs that otherwise only address air pollution (i.e.,
ambient air, which does not include the stratospheric ozone layer).
Comment: A commenter stated that EPA's claim to authority conflicts
with the Department of Labor's administrative ``whistleblower'' case
law. These cases hold that a whistleblower action may proceed under the
CAA only when the complaint concerned substances emitted to the ambient
air. Claims regarding air quality within the workplace are brought
under the whistleblower provisions of the OSH Act.
Response: The commenter overstates the import of the decisions
issued by the Administrative Review Board. In each of the cited
decisions, the Board examined the specific circumstances before it to
determine which statutory whistleblower provision provided the basis
for the claimed action. While making general pronouncements that the
CAA regulates ambient air and OSHA regulates air within the workplace,
none of these opinions specifically addressed the scope of EPA's
authority under section 612, the SNAP provisions of the Act.
Comment: A commenter stated that even if ventilation or other
measures could reduce exposures to below 25 ppm, there is nothing to
ensure that companies will take such measures. This commenter also
stated that he is aware of nPB formulators that have already announced
they will not adhere to this voluntary standard. Three commenters, all
representing local environmental regulators, stated that a
recommendation that worker exposure be limited to 25 ppm will not carry
the enforcement powers of an OSHA standard, and that this lack of
control will encourage the use of nPB in applications beyond those
envisioned by EPA. Another commenter asserted that the proposed
exposure limits (both the AEL and the STEL) should be established as
use conditions, citing Section 612 as the basis for EPA's authority to
do so. This commenter stated that a precedent has already been set for
EPA to accept an alternative chemical subject to use conditions--
including that observance of workplace concentration limits--in the
adhesives, aerosols, and solvent cleaning sectors (e.g., HCFC-225 ca/
cb, HFC-4310mee, monochlorotoluenes, benzotrifluorides; 40 CFR part 82,
subpart G, appendices A, B, and D).
Response: EPA agrees that a recommended AEL from EPA does not
provide the same level of protection as an enforceable standard from
OSHA. We also agree that EPA has the authority under section 612 to
require use conditions in those circumstances where use of a
potentially promising substitute would otherwise be unacceptable unless
those use conditions are met and there are significant concerns about
the ability of industry to meet a safe level for use. In the preamble
to the original SNAP rule,
[[Page 30160]]
we recognized that there may be cases where OSHA has not regulated
worker exposure to a substitute. We went on to say that ``EPA
anticipates applying use conditions only in the rare instances where
clear regulatory gaps exist, and where an unreasonable risk would exist
in the absence of any conditions.'' For the solvent cleaning end use,
we do not believe that there is an unreasonable risk in the absence of
a use condition. Available exposure data show that roughly 88% of
samples from nPB users in solvent cleaning met an exposure level of 25
ppm, 81% met an exposure level of 18 ppm, and 70% met an exposure level
of 10 ppm (U.S. EPA, 2003). One nPB supplier provided evidence that on
the few occasions when nPB concentrations from vapor degreasers were
higher than the company's recommended AEL of 25 ppm, users were able to
reduce exposure easily and inexpensively by changing work practices,
such as reducing drafts near the cleaning equipment (Kassem, 2003).
Therefore, we expect that users of nPB in the solvent cleaning sector
following typical industry practices and using typical equipment for
vapor degreasing will continue to use nPB at levels considered safe for
workers. As noted above, this is the approach we indicated we would
follow at the time of the original SNAP rule and we have taken this
same approach for many other solvents where users are readily able to
meet a workplace exposure limit that will protect human health and
there is no enforceable OSHA PEL (e.g., HFC-365mfc and
heptafluorocyclopentane at 65 FR 78977, ketones, alcohols, esters, and
hydrocarbons at 59 FR 13044).
Comment: One commenter claims that section 6 of the Occupational
Safety and Health Act requires OSHA to make certain legal findings
before promulgating a standard and that therefore EPA has no authority
to develop any AEL applicable to a workplace environment. Furthermore,
since OSHA is the only agency that can make standards applicable in the
workplace, any level developed by EPA is misleading. The same commenter
said that EPA offers no reasoning as to why a different methodology for
setting an AEL (from that of OSHA) is necessary or advisable.
Therefore, this commenter believes that the Agency's process violates
equal protection unless EPA is publishing a new standard for chemical
review under SNAP.
Response: In this rulemaking, EPA has not developed an AEL that is
applicable in any workplace. Rather, EPA looked at a range of possible
AELs for purposes of determining whether nPB will pose significantly
greater risk than other substitutes that are available in the same end
use. The range of levels EPA used for its analysis is not binding.
Moreover, as explained above in section V.B.2, EPA has concluded that
for purposes of finding nPB acceptable in the solvent cleaning end use,
it is not necessary to provide a non-binding recommended workplace
exposure limit because these users in the solvent cleaning sector are
regularly able to comply with even the lowest level EPA considered in
performing its evaluation.
For standards covering hazardous chemicals in the workplace, the
OSH Act requires OSHA to set standards that, to the extent feasible,
ensure that workers do not suffer material impairments of health.
Standards established by OSHA under their statute have not typically
prohibited the use of the chemical in any particular application, but
instead establish performance goals for the use and handling of
hazardous chemicals that reduce such risks to the extent feasible. The
available information on health effects of nPB on workers is not
sufficiently well-characterized to develop a standard based on avoiding
material impairments of health in workers. Most manufacturers and
organizations that set workplace exposure limits such as ACGIH and the
American Industrial Hygiene Association use an approach similar to
EPA's and do not base exposure limits on avoiding material impairments
of health in workers. Because of the need for large amounts of well-
characterized data from the workplace on exposures and associated
health effects to prepare an AEL to prevent material impairment, if EPA
were to develop AELs for nPB and other chemicals based on the approach
required by section 6 of the OSH Act, EPA would effectively be unable
to assess the human health effects of ODS alternatives in time to
assist industry in transitioning away from ODS. In order to provide for
a more timely assessment of human health effects, as well as one that
is consistent with federal guidelines of the National Academies of
Science (NAS, 1983), we have considered exposure levels following EPA
guidance (U.S. EPA, 1994b). Different substances have different
toxicological effects and those effects must be considered based on the
best scientific information and methodologies available. It is
incorrect to claim that such reviews, which focus on the effects of
different substances, resulted in disparate treatment of nPB.
VI. How can I use nPB as safely as possible?
Below are actions that will help nPB users minimize exposure
levels:
All End Uses
All users of nPB should wear appropriate personal
protective equipment, including chemical goggles, flexible laminate
protective gloves (e.g., Viton, Silvershield) and chemical-resistant
clothing. Special care should be taken to avoid contact with the skin
since nPB, like many halogenated solvents, can be absorbed through the
skin. Refer to OSHA's standard for the selection and use of Personal
Protective Equipment, 29 CFR 1910.132.
Limit worker exposure to solvents to minimize any
potential adverse health effects. Workers should avoid staying for long
periods of time in areas near where they have been using the solvent.
Where possible, shorten the period during each day when a worker is
exposed. Where respiratory protection is necessary to limit worker
exposures, respirators must be selected and used in accordance with
OSHA's Respiratory Protection standard, 29 CFR 1910.134.
Use less solvent, or use a different solvent, either alone
or in a mixture with nPB.
Follow all recommended safety precautions specified in the
manufacturer's MSDS.
Workers should receive safety training and education that
includes potential health effects of exposure to nPB, covering
information included on the appropriate MSDSs, as required by OSHA's
Hazard Communication Standard (29 CFR 1910.1200).
Request a confidential consultation from your State
government on all aspects of occupational safety and health. You can
contact the appropriate state agency that participates in OSHA's
consultation program. These contacts are on OSHA's Web site at http://www.osha.gov/oshdir/consult.html. For further information on OSHA's
confidential consultancy program, visit OSHA's web page at http://www.osha.gov/html/consultation.html.
Use the employee exposure monitoring programs and product
stewardship programs where offered by manufacturers and formulators of
nPB-based products.
If the manufacturer or formulator of your nPB-based
product does not have an exposure monitoring program, we recommend that
you start your own exposure monitoring program, and/or request a
confidential consultation from your State government. A medical
monitoring program should be
[[Page 30161]]
established for the early detection and prevention of acute and chronic
effects of exposure to nPB. The workers' physician(s) should be given
information about the adverse health effects of exposure to nPB and the
workers' potential for exposure.
For non-aerosol solvent cleaning, follow guidelines in the
National Emissions Standards for Hazardous Air Pollutant (NESHAP) for
halogenated solvents cleaning if you are using nPB. The equipment and
procedural changes described in the halogenated solvents NESHAP can
reduce emissions, reduce solvent losses and lower the cost of cleaning
with organic solvents. For more information on the halogenated solvents
NESHAP, visit http://www.epa.gov/ttn/atw/eparules.html and http://www.epa.gov/ttn/atw/degrea/halopg.html. We note that these steps are
useful for reducing exposure to any industrial solvent, and not just
nPB.
VII. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review
Under Executive Order (EO) 12866 (58 FR 51735, October 4, 1993),
this action is a ``significant regulatory action.'' It raises novel
legal or policy issues arising out of legal mandates, the President's
priorities, or the principles set forth in the Executive Order.
Accordingly, EPA submitted this action to the Office of Management and
Budget (OMB) for review under EO 12866 and any changes made in response
to OMB recommendations have been documented in the docket for this
action.
In addition, EPA prepared an analysis of the potential costs and
benefits associated with this action. This analysis is contained in the
document ``Analysis of Economic Impacts of nPB Rulemaking.'' A copy of
the analysis is available in the docket for this action (Ref. EPA-HQ-
OAR-2002-0064) and the analysis is briefly summarized here.
In our analysis, we assumed that capital costs are annualized over
15 years or less using a discount rate for determining net present
value of 7.0%. The acceptability determination for solvents cleaning
imposes no requirements and thus creates no additional cost to users.
EPA also considered potential costs end users could incur to meet
acceptable exposure levels if they are not already achieving it. EPA
found that those users using nPB-based solvents in a vapor degreaser
would save money by reducing solvent losses, and that the savings would
recover the costs of emissions controls (e.g., secondary cooling coils,
automated lifts or hoists) within a year of installation. Based on
evidence from solvent suppliers, EPA believes that some of those users
would have chosen to use nPB in order to avoid meeting requirements of
the national emission standard for halogenated solvents cleaning and
that they would only become aware of the potential savings due to
reduced solvent usage as a result of this proposal (Ultronix, 2001;
Kassem, 2003; Tattersall, 2004). Based on available exposure data for
each sector, we assumed that 81% of nPB users in the non-aerosol
solvent cleaning sector already achieve exposure levels at the lowest
level that we considered, i.e., 18 ppm (U.S. EPA, 2003). Of those nPB
solvent users with exposure levels above that, we examined the cost
associated with reducing emissions on average by 60%.
If all nPB users in solvent cleaning reduced exposures to 18 ppm,
EPA estimates that users would save up to $2 million dollars per year,
overall (U.S. EPA, 2007). The value will depend on the number of users
that attempt to meet an acceptable exposure level which is already
being achieved with existing equipment, the initial exposure level of
cleaning solvent users, the price of nPB, and the amount of emission
control equipment installed.
B. Paperwork Reduction Act
There are no new requirements for reporting or recordkeeping or
information collection associated with this final rule. The final rule
merely allows the use of substitutes for ozone-depleting substances,
without requiring the collection, keeping, or reporting of information.
OMB has previously approved the information collection requirements
contained in the existing regulations in subpart G of 40 CFR part 82
under the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et
seq. and has assigned OMB control number 2060-0226 (EPA ICR No.
1596.06). This ICR included five types of respondent reporting and
record-keeping activities pursuant to SNAP regulations: submission of a
SNAP petition, filing a SNAP//Toxic Substance Control Act (TSCA)
Addendum, notification for test marketing activity, record-keeping for
substitutes acceptable subject to use restrictions, and record-keeping
for small volume uses. A copy of the OMB approved Information
Collection Request (ICR) may be obtained from Susan Auby, Collection
Strategies Division; U.S. Environmental Protection Agency (2822T); 1200
Pennsylvania Ave., NW., Washington, DC 20460 or by calling (202) 566-
1672.
Burden means the total time, effort, or financial resources
expended by persons to generate, maintain, retain, or disclose or
provide information to or for a Federal agency. This includes the time
needed to review instructions; develop, acquire, install, and utilize
technology and systems for the purposes of collecting, validating, and
verifying information, processing and maintaining information, and
disclosing and providing information; adjust the existing ways to
comply with any previously applicable instructions and requirements;
train personnel to be able to respond to a collection of information;
search data sources; complete and review the collection of information;
and transmit or otherwise disclose the information.
An agency may not conduct or sponsor, and a person is not required
to respond to a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for EPA's
regulations in 40 CFR are listed in 40 CFR part 9.
C. Regulatory Flexibility Act
The Regulatory Flexibility Act (RFA) generally requires an agency
to prepare a regulatory flexibility analysis of any rule subject to
notice and comment rulemaking requirements under the Administrative
Procedure Act or any other statute unless the agency certifies that the
rule will not have a significant economic impact on a substantial
number of small entities. Small entities include small businesses,
small organizations, and small governmental jurisdictions. The RFA
provides default definitions for each type of small entity. Small
entities are defined as: (1) A small business as defined by the Small
Business Administration's (SBA) regulations at 13 CFR 121.201; (2) a
small governmental jurisdiction that is a government of a city, county,
town, school district or special district with a population of less
than 50,000; and (3) a small organization that is any not-for-profit
enterprise which is independently owned and operated and is not
dominant in its field. However, the RFA also authorizes an agency to
use alternate definitions for each category of small entity, ``which
are appropriate to the activities of the agency'' after proposing the
alternate definition(s) in the Federal Register and taking comment. 5
U.S.C. 601(3)--(5). In addition, to establish an alternate small
business definition, agencies must consult with SBA's Office of
Advocacy.
For purposes of assessing the impacts of EPA's June 2003 proposed
rule on
[[Page 30162]]
small entities, EPA proposed to define ``small business'' as a small
business with less than 500 employees, rather than use the individual
SBA size standards for the numerous NAICS subsectors and codes to
simplify the economic analysis. We solicited comments on the use of
this alternate definition for this analysis in the June 2003 NPRM and
received no public comments. EPA also consulted with the SBA's Office
of Advocacy on the use of an alternate small business definition of 500
employees. The Office of Advocacy concurred with EPA's use of this
alternate definition to analysis the economic impacts on small
businesses from the use of n-propyl bromide as an acceptable substitute
for use in metals, precision, and electronics cleaning, and in aerosols
and adhesives end-uses. Therefore, EPA used this alternate definition
for this final rule. We believe that no small governments or small
organizations are affected by this rule. This approach slightly reduced
the number of small businesses included in our analysis and slightly
increased the percentage of small businesses for whom the analysis
indicated the use of nPB in metals, precision, and electronics cleaning
may have an economically significant impact. The number and types of
small businesses that are subject to this rule have not changed
significantly since the June 2003 proposal. EPA intends to use this
alternate definition of ``small business'' for regulatory flexibility
analyses under the RFA for any other rule related to the use of nPB as
a chemical alternative to ozone-depleting substances (ODS) for the same
end uses in the June 2003 NPRM (e.g., adhesives and aerosol solvents).
After considering the economic impacts of this rule on small
entities, I certify that this action will not have a significant
economic impact on a substantial number of small entities. EPA
estimates that approximately 1470 users of nPB industrial cleaning
solvents (e.g., cleaning with vapor degreasers) would be subject to
this rule. This rule lists nPB as an acceptable substitute for ODS.
This rule itself does not impose any binding requirements on users of
nPB, and therefore will not have a significant economic impact on a
substantial number of small entities. EPA did however analyze the
potential economic impacts on small businesses that use nPB for
cleaning solvents for metals cleaning, electronics cleaning, or
precision cleaning. The details of EPA's analysis are described in the
supporting materials for this rulemaking (U.S. EPA, 2007). Based on its
analysis, EPA believes businesses using nPB-based cleaning solvents for
metals cleaning, electronics cleaning, or precision cleaning would
experience significant cost benefits by reducing spending on solvent.
D. Unfunded Mandates Reform Act
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public
Law 104-4, establishes requirements for Federal agencies to assess the
effects of their regulatory actions on State, local, and tribal
governments and the private sector. Under section 202 of the UMRA, EPA
generally must prepare a written statement, including a cost-benefit
analysis, for proposed and final rules with ``Federal mandates'' that
may result in expenditures to State, local, and tribal governments, in
the aggregate, or to the private sector, of $100 million or more in any
one year. Before promulgating an EPA rule for which a written statement
is needed, section 205 of the UMRA generally requires EPA to identify
and consider a reasonable number of regulatory alternatives and adopt
the least costly, most cost-effective or least burdensome alternative
that achieves the objectives of the rule. The provisions of section 205
do not apply when they are inconsistent with applicable law. Moreover,
section 205 allows EPA to adopt an alternative other than the least
costly, most cost-effective or least burdensome alternative if the
Administrator publishes with the final rule an explanation why that
alternative was not adopted. Before EPA establishes any regulatory
requirements that may significantly or uniquely affect small
governments, including tribal governments, it must have developed under
section 203 of the UMRA a small government agency plan. The plan must
provide for notifying potentially affected small governments, enabling
officials of affected small governments to have meaningful and timely
input in the development of EPA regulatory proposals with significant
Federal intergovernmental mandates, and informing, educating, and
advising small governments on compliance with the regulatory
requirements. EPA has determined that this rule does not contain a
Federal mandate that may result in expenditures of $100 million or more
for State, local, and tribal governments, in the aggregate, or the
private sector in any one year. This final rule does not affect State,
local, or tribal governments. This rule contains no enforceable
requirements. The impact of users meeting the AEL range discussed in
the preamble is from a savings of $2 million per year to a cost of $0
million per year. Therefore, the impact of this rule on the private
sector is less than $100 million per year. Thus, this rule is not
subject to the requirements of sections 202 and 205 of the UMRA. EPA
has determined that this rule contains no regulatory requirements that
might significantly or uniquely affect small governments. This
regulation applies directly to facilities that use these substances and
not to governmental entities.
E. Executive Order 13132: 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.''
This final rule does not have federalism implications. It will not
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,
as specified in Executive Order 13132. This regulation applies directly
to facilities that use these substances and not to governmental
entities. Thus, Executive Order 13132 does not apply to this rule.
F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
Executive Order 13175, entitled ``Consultation and Coordination
with Indian Tribal Governments'' (65 FR 67249, November 6, 2000),
requires EPA to develop an accountable process to ensure ``meaningful
and timely input by tribal officials in the development of regulatory
policies that have tribal implications.'' ``Policies that have tribal
implications'' is defined in the Executive Order to include regulations
that have ``substantial direct effects on one or more Indian tribes, on
the relationship between the Federal government and the Indian tribes,
or on the distribution of power and responsibilities between the
Federal government and Indian tribes.''
This final rule does not have tribal implications. It will not have
substantial direct effects on tribal governments, on the relationship
between the Federal government and Indian tribes, or on the
[[Page 30163]]
distribution of power and responsibilities between the Federal
government and Indian tribes, as specified in Executive Order 13175.
This final rule would not significantly or uniquely affect the
communities of Indian tribal governments, because this regulation
applies directly to facilities that use these substances and not to
governmental entities. Thus, Executive Order 13175 does not apply to
this final rule.
G. Executive Order 13045: Protection of Children From Environmental
Health and Safety Risks
Executive Order 13045: ``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 Executive Order 12866, and (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.
This final rule is not subject to the Executive Order because it is
not economically significant as defined in Executive Order 12866, and
because the Agency does not have reason to believe the environmental
health or safety risks addressed by this action present a
disproportionate risk to children. The exposure limits and
acceptability listings in this final rule apply to the workplace. These
are areas where we expect adults are more likely to be present than
children, and thus, the agents do not put children at risk
disproportionately.
H. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use
This rule is not a ``significant energy action'' as defined in
Executive Order 13211, ``Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use'' (66 FR 28355
(May 22, 2001)) because it is not likely to have a significant adverse
effect on the supply, distribution, or use of energy. This action would
impact manufacturing of various metal, electronic, medical, and optical
products cleaned with solvents containing nPB and products made with
adhesives containing nPB. Further, we have concluded that this rule is
not likely to have any adverse energy effects.
I. National Technology Transfer and Advancement Act
Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (``NTTAA''), Public Law 104-113, section 12(d) (15 U.S.C.
272 note) directs EPA to use voluntary consensus standards in its
regulatory activities unless to do so would be inconsistent with
applicable law or otherwise impractical. Voluntary consensus standards
are technical standards (e.g., materials specifications, test methods,
sampling procedures, and business practices) that are developed or
adopted by voluntary consensus standards bodies. The NTTAA directs EPA
to provide Congress, through OMB, explanations when the Agency decides
not to use available and applicable voluntary consensus standards.
This action does not involve technical standards. Therefore, EPA
did not consider the use of any voluntary consensus standards.
J. Congressional Review Act
The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the agency promulgating
the rule must submit a rule report, which includes a copy of the rule,
to each House of the Congress and to the Comptroller General of the
United States. EPA will submit a report containing this rule and other
required information to the U.S. Senate, the U.S. House of
Representatives, and the Comptroller General of the United States prior
to publication of the rule in the Federal Register. A major rule cannot
take effect until 60 days after it is published in the Federal
Register. This action is not a ``major rule'' as defined by 5 U.S.C.
804(2). This rule will be effective July 30, 2007.
VIII. References
The documents below are referenced in the preamble. All documents
are located in the Air Docket at the address listed in section I.B.1 at
the beginning of this document. Unless specified otherwise, all
documents are available electronically through the Federal Docket
Management System, Docket EPA-HQ-OAR-2002-0064. Some specific
items are available only in hard copy in dockets A-2001-07 or A-92-42
(legacy docket numbers for SNAP nPB rule and for SNAP program and
submissions). Numbers listed after the reference indicate the docket
and item numbers.
Availability
IBSA, 2002. Record of September 5, 2002 Meeting with the
International Brominated Solvents Association Inc. (A-2001-07, II-D-
60)
Ozone-Depletion Potential and Other Environmental Impacts
ATSDR, 1994. Toxicological Profile For Acetone. Agency for Toxic
Substances and Disease Registry. May, 1994. Available at http://www.atsdr.cdc.gov/toxprofiles/tp21-c5.pdf (EPA-HQ-OAR-2002-0064-
0118)
ATSDR, 1996. Toxicological Profile For 1,2-Dichloroethene. Agency
for Toxic Substances and Disease Registry. August, 1996. Available
at http://www.atsdr.cdc.gov/toxprofiles/tp87-c5.pdf (EPA-HQ-OAR-
2002-0064-0113)
ATSDR, 1997. Toxicological Profile For Trichloroethylene. Agency for
Toxic Substances and Disease Registry. September, 1997. Available at
http://www.atsdr.cdc.gov/toxprofiles/tp19-c5.pdf (EPA-HQ-OAR-2002-
0064-0123)
ATSDR, 2004. Draft Toxicological Profile For 1,1,1-Trichloroethane.
Agency for Toxic Substances and Disease Registry. September, 2004.
Updated draft for comment. Available at http://www.atsdr.cdc.gov/toxprofiles/tp70-c6.pdf (EPA-HQ-OAR-2002-0064-0132)
EDSTAC, 1998. Final Report of the Endocrine Disruptor Screening and
Testing Advisory Committee. August, 1998. (EPA-HQ-OAR-2002-0064-
0136)
Geiger et al., 1998. Geiger, D.L., Call, D.J., and Brooke, L.T.
1988. Acute Toxicities of Organic Chemicals to Fathead Minnows
(Pimephales promelas), Vol. 4. In: Center for Lake Superior
Environmental Stud., Univ. of Wisconsin-Superior, Superior, WI
I:355. (Summarized in ICF, 2004a)
HSDB, 2004. Hazardous Substances Databank File for 1-Bromopropane.
Accessed 1/2004 from the World Wide Web at http://
toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~dLwM9e:1 (Summarized
in ICF, 2004a)
ICF, 2004a. ICF Consulting. Memo to E. Birgfeld, EPA, re: nPB
Aquatic Toxicity. January 19, 2004. (EPA-HQ-OAR-2002-0064-0193)
LaGrega, M., Buckingham, P., Evans, J., and Environmental Resources
Management, 2001. Hazardous Waste Management. Second Edition.
McGraw-Hill, New York, NY. 2001. (EPA-HQ-OAR-2002-0064-0112)
Linnell, 2003. Comments from the Electronics Industry Alliance.
(EPA-HQ-OAR-2002-0064 items -0043, -0044, and -0045)
NPS, 1997. Irwin, R.J., M. VanMouwerik, L. Stevens, M.S. Seese, and
W. Basham. 1997. Environmental Contaminants Encyclopedia. National
Park Service, Water Resources Division, Fort Collins, Colorado.
(EPA-HQ-OAR-2002-0064-0086)
[[Page 30164]]
Steminiski, 2003. July 27, 2003 Comment from J. Steminiski, PhD.
(EPA-HQ-OAR-2002-0064-0035 and -0043)
U.S. Economic Census, 2002a. General Summary: 2002. Subject Series.
Report No. EC02-31SG-1, October, 2005. U.S. Census Bureau. (EPA-HQ-
OAR-2002-0064-0133)
U.S. Economic Census, 2002b. U.S. Economic Census for Island Areas,
2002. Report for Northern Marianas Islands, Rpt. No. IA02-00A-NMI,
May, 2004. U.S. Census Bureau. (EPA-HQ-OAR-2002-0064-0091)
U.S. Economic Census, 2002c. U.S. Economic Census for Island Areas,
2002. Report for Guam, Rpt. No. IA02-00A-GUAM, March, 2005. U.S.
Census Bureau. (EPA-HQ-OAR-2002-0064-0102)
U.S. Economic Census, 2002d. U.S. Economic Census for Island Areas,
2002. Report for Virgin Islands, Rpt. No. IA02-00A-VI , April, 2005.
U.S. Census Bureau. (EPA-HQ-OAR-2002-0064-0131)
U.S. Economic Census, 2002e. U.S. Economic Census for Island Areas,
2002. Report for American Samoa, Rpt. No. IA02-00A-AS, April, 2005.
U.S. Census Bureau. (EPA-HQ-OAR-2002-0064-0103)
U.S. Economic Census, 2002f. U.S. Economic Census for Island Areas,
2002. Report for Puerto Rico: Manufacturing, Rpt. No. IA02-00I-PRM,
October, 2005. U.S. Census Bureau. (EPA-HQ-OAR-2002-0064-0107)
U.S. EPA, 1980. Ambient Water Quality Criteria for
Dichloroethylenes. EPA 440/5-80-041 October, 1980. Available at
http://www.epa.gov/waterscience/pc/ambientwqc/dichloroethylenes80.pdf
U.S. EPA, 1992. Hazard Assessment Guidelines for Listing Chemicals
on the Toxic Release Inventory, Revised Draft. Washington, DC:
Office of Pollution, Prevention and Toxics. As referenced in ICF,
2004a.
U.S. EPA, 1994a. Chemical Summary for Methyl Chloroform, prepared by
Office of Pollution Prevention and Toxics, August, 1994. (EPA-HQ-
OAR-2002-0064-0121)
WMO, 2002: Scientific Assessment of Ozone Depletion: 2002, Global
Ozone Research and Monitoring Project--Report No. 47, Geneva, 2003
Full report available online at http://esrl.noaa.gov/csd/assessments/ (A-2001-07, II-A-20)
Wuebbles, Donald J. 2002. ``The Effect of Short Atmospheric
Lifetimes on Stratospheric Ozone.'' Written for Enviro Tech
International, Inc. Department of Atmospheric Sciences, University
of Illinois-Urbana. (EPA-HQ-OAR-2002-0064-0114)
Flammability and Fire Safety
BSOC, 2000. February 1, 2000 Tabulation of Flammability Studies on
n-Propyl Bromide from the Brominated Solvents Committee, and other
information on flammability of n-propyl bromide. (A-2001-07, II-D-
45)
Miller, 2003. Albemarle Corporation comments-Flash Point Data for n-
Propyl Bromide. (EPA-HQ-OAR-2002-0064-0040)
Morford, 2003a, b. Enviro Tech International Comment re Section IV D
Flammability with Exhibits (7/25/03) (EPA-HQ-OAR-2002-0064-0030 and
EPA-HQ-OAR-2002-0064-0031)
Morford, 2003c. Enviro Tech Int. Flammability of nPB & Comparison
With Methylene Chloride-Additional Comments on Flammability (7/29/
03) (EPA-HQ-OAR-2002-0064-0036)
Shubkin, 2003. R. Shubkin, Poly Systems, EPA received 7/23/03 Re:
Comment on Flammability of n-Propyl Bromide as Discussed in Proposed
Rule Published in Federal Register (EPA-HQ-OAR-2002-0064-0025)
Weiss Cohen, 2003. T. Weiss Cohen, Dead Sea Bromine Group, 7/31/2003
Comment to Federal Register Proposed Rules of June 3, 2003, on
Protection of Stratospheric Ozone: Listing of Substitutes for Ozone-
Depleting Substances--n-Propyl Bromide (EPA-HQ-OAR-2002-0064-0053)
Human Health
ACGIH, 1991. Skin Notation Documentation for Methyl Chloride.
Available online at http://www.acgih.org.
ACGIH, 2005. Documentation for Threshold Limit Value for 1-
Bromopropane. 2005. Available online at http://www.acgih.org.
Albemarle, 2003. Product Description for Abzol([supreg]) Cleaners.
2003. (EPA-HQ-OAR-2002-0064-0148)
Beck and Caravati, 2003. Neurotoxicity associated with 1-
bromopropane exposure. Utah Poison Control Center, University of
Utah, Salt Lake City, UT. J Toxicology Clinical Toxicology
41(5):729. (Abstract from conference). 2003. (EPA-HQ-OAR-2002-0064-
0111)
CERHR, 2002a. NTP-Center for the Evaluation of Risks to Human
Reproduction Expert Panel Report on the Reproductive and
Developmental Toxicity of 1-Bromopropane [nPB]. March 2002. (EPA-HQ-
OAR-2002-0064-0096)
ClinTrials, 1997a. A 28-Day Inhalation Study of a VaporFormulation
of ALBTA1 in the Albino Rat. Report No. 91189. Prepared by
ClinTrials BioResearch Laboratories, Ltd., Senneville, Quebec,
Canada. May 15, 1997. Sponsored by Albemarle Corporation, Baton
Rouge, LA. (A-91-42, X-A-4)
ClinTrials, 1997b. ALBTA1: A 13-Week Inhalation Study of a Vapor
Formulation of ALBTA1 in the Albino Rat. Report No. 91190. Prepared
by ClinTrials BioResearch Laboratories, Ltd., Senneville, Quebec,
Canada. February 28, 1997. Sponsored by Albemarle Corporation, Baton
Rouge, LA. (A-91-42, X-A-5)
Dunson et al, 2002. Dunson, D., Colombo, and B., Baird, D. Changes
with age in the level and duration of fertility in the menstrual
cycle. Human Reproduction, Vol. 17, No. 5, pp. 1399-1403, 2002.
(EPA-HQ-OAR-2002-0064-0120)
Fueta et al., 2002. Y. Fueta, K. Fukunaga, T. Ishidao, H. Hori.
Hyperexcitability and changes in activities of Ca2+/calmodulin-
dependent kinase II and mitogen-activated protein kinase in the
hippocampus of rats exposed to 1-bromopropane. 2002. Life Sciences
72 (2002) 521-529. (EPA-HQ-OAR-2002-0064-0115)
Fueta et al., 2004. Y. Fueta, T. Fukuda, T. Ishidao, H. Hori.
Electrophysiology and immunohistochemistry in the hippocampal CA1
and the Dentate Gyrus of Rats Chronically exposed to 1-Bromopropane,
a Substitute for Specific Chlorofluorocarbons. Neuroscience 124
(2004) 593-603. (EPA-HQ-OAR-2002-0064-0142)
Honma et al., 2003. Honma, T, Suda M, Miyagawa M. ``Inhalation of 1-
bromopropane causes excitation in the central nervous system of male
F344 rats.'' Neurotoxicology. 2003 Aug; 24 (4-5):563-75. (EPA-HQ-
OAR-2002-0064-0138)
ICF, 2002. Risk Screen for Use of N-Propyl Bromide. ICF Consulting.
Prepared for U.S. EPA, May, 2002. (EPA-HQ-OAR-2002-0064-0006 through
-0012)
ICF, 2004b. ICF Consulting. ICF Consulting Review of the TERA
Report. December 13, 2004
ICF, 2004c. ICF Consulting. External Expert Review Panel on n-Propyl
Bromide. December 13, 2004
ICF, 2004d. ICF Consulting. Review of ACGIH's Proposed Threshold
Limit Value for 1-Bromopropane. April 26, 2004
ICF, 2006a. ICF Consulting. Risk Screen on Substitutes for Ozone-
Depleting Substances for Adhesive, Aerosol Solvent, and Solvent
Cleaning Applications. Proposed Substitute: n-Propyl Bromide. April
18, 2006. Attachments: A, Determination of an AEL; B, Derivation of
an RfC; C, Evaluation of the Global Warming Potential; D,
Occupational Exposure Analysis for Adhesive Applications; E,
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ICF, 2006b. ICF Consulting. Revised Memorandum regarding RTI
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[[Page 30165]]
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5
O'Malley, 2004. Letter from Nancy O'Malley, Toxicology Advisor,
Albemarle Corporation to The Science Group of the American
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July 30, 2004. (EPA-HQ-OAR-2002-0064-0128)
Raymond and Ford, 2005. ``Clinical Case Presentations from a Foam
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Risotto, 2003. Comments of the Halogenated Solvents Industry
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Rodricks, 2002. October 21, 2002 remarks from Dr. J. Rodricks,
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Rozman and Doull, 2002. ``Derivation of an Occupational Exposure
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Stelljes and Wood, 2004. Stelljes, M., Wood, R. Development of an
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U.S. EPA, 1995b. The Use of the Benchmark Dose Approach in Health
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Wang et al., 2003. H. Wang, G. Ichihara, H. Ito, K. Kato, J. Kitoh,
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Werner, 2003. Comments from 3M on nPB proposed rule. (EPA-HQ-OAR-
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WIL, 2001. WIL Research Laboratories. ``An inhalation two-generation
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0097)
How Is EPA Responding to Comments?
ACGIH, 1991. Full citation above in ``Human Health'' section.
ACGIH, 2004. TLVs and BEIs: Threshold Limit Values for Chemical
Substances and Physical Agents, Biological Exposure Indices.
American Conference of Governmental Industrial Hygienists.
[[Page 30166]]
Cincinnati, OH. Available online at http://www.acgih.org.
ACGIH, 2005. Full citation above in ``Human Health'' section.
Beck and Caravati, 2003. Full citation above in ``Human Health''
section.
Chemtura, 2006. Material Safety Data Sheet for n-propyl bromide.
April, 2006. (EPA-HQ-OAR-2002-0064-0151)
ClinTrials, 1997a. Full citation above in ``Human Health'' section.
ClinTrials, 1997b. Full citation above in ``Human Health'' section.
Doull and Rozman, 2001. Doull and Rozman, 2001. Derivation of an
Occupational Exposure Limit for n-Propyl Bromide, prepared by John
Doull, Ph.D., M.D., and Karl K. Rozman, Ph.D., D.A.B.T. submitted by
Envirotech International, Inc. (A-2001-07, II-D-14)
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section.
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Intraperitoneal Route in Mice. n-Propyl Bromide. Study No. 12122
MAS. Study Director, Brigitte Molinier. Study performed by Centre
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ERG, 2004. Analysis of Health and Environmental Impacts of ODS
Substitutes--Evaluating the need to set a short-term exposure or
ceiling limit for n-propyl bromide. ERG. June 8, 2004.
Farr, 2003. Comment on proposed rule on n-propyl bromide from Craig
Farr, Atofina. July 31, 2003. (EPA-HQ-OAR-2002-0064-0060)
HDSB, 2004. Full citation above in ``Ozone-Depletion Potential and
Other Environmental Impacts'' section.
HESIS, 2003. California Department of Health Services--HESIS 1-
Bromopropane (n-Propyl Bromide) Health Hazard Alert. (EPA-HQ-OAR-
2002-0064-0039)
Honma, 2003. Full citation above in ``Human Health'' section.
ICF, 2002a. Full citation above in ``Human Health'' section.
ICF, 2004a. Full citation above in ``Ozone-Depletion Potential and
Other Environmental Impacts'' section.
ICF, 2006a. Full citation above in ``Human Health'' section.
ICF, 2006b. Full citation above in ``Human Health'' section.
ICF, 2006c. ICF Consulting. Evaluation of Memorandum from Dr. M.
Stelljes. May, 2006.
Ichihara, 1999. Full citation above in ``Human Health'' section.
Ichihara, 2000a. Full citation above in ``Human Health'' section.
Ichihara, 2002. Full citation above in ``Human Health'' section.
Ichihara, 2004a. Full citation above in ``Human Health'' section.
Ichihara, 2004b. Full citation above in ``Human Health'' section.
Kassem, 2003. January 10, 2003 Letter from O.M. Kassem, Albemarle
Corporation to K. Bromberg, Small Business Administration Re: n
propyl bromide SNAP. (A-2001-07, II-D-78)
Linnell, 2003. Full citation above in ``Ozone-Depletion Potential
and Other Environmental Impacts'' section.
Majersik, 2004. Full citation above in ``Human Health'' section.
Majersik, 2005. Full citation above in ``Human Health'' section.
MOP 18, 2006. Report of the Eighteenth Meeting of the Parties to the
Montreal Protocol on Substances that Deplete the Ozone Layer.
November 16, 2006. (EPA-HQ-OAR-2002-0064-0163)
Morford, 2003a. Full citation above in ``Flammability'' section.
Morford, 2003b. Full citation above in ``Flammability'' section.
Morford, 2003c. Full citation above in ``Flammability'' section.
Morford, 2003d. Support for EPA Proposal to Approve n propyl bromide
and Comments Pursuant to Section D. Flammability of Protection of
Stratospheric Ozone: Listing of Substitutes for Ozone Depleting
Substances--n-Propyl Bromide: Proposed Rule Federal Register Vol. 68
No. 106, June 3, 2003. Enviro Tech International, Inc. Comments
Regarding Proposed Rule & Exhibit A Richard Morford, Enviro Tech
International. August 3, 2003. (EPA-HQ-OAR-2002-0064-0047)
Morford, 2003e. Enviro Tech International, Inc. Combined Exhibits to
Comment 0047/Morford, 2003e on Proposed Rule Richard Morford, Enviro
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Morford, 2003f. Initial Comments to Protection of Stratospheric
Ozone: Listing of Substitutes for Ozone Depleting Substances--n-
Propyl bromide: Proposed Rule Federal Register Vol. 68 No. 106, June
3, 2003. Richard Morford, Enviro Tech International. June 26, 2003.
(EPA-HQ-OAR-2002-0064-0002)
Morford, 2003g. Comment regarding proposed restriction on isopropyl
bromide Richard Morford, Enviro Tech International. August 3, 2003.
(EPA-HQ-OAR-2002-0064-0042)
Morford, 2003h. Enviro Tech International Inc Comment Regarding iPB
Content Restriction Exhibit A 04-Aug-2003 (EPA-HQ-OAR-2002-0064-
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Morford, 2003i. White Paper: ``EPA Is Unlawfully Regulating
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2003-0064-0049)
NTP, 2003. Full citation above in ``Human Health'' section.
PBT Profiler, 2007. Results from the PBT Profiler Tool for 1-
bromopropane, CAS No. 106-94-5. Downloaded on February 9, 2007 from
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Risotto, 2003. Full citation above in ``Human Health'' section.
Rodricks, 2002. Full citation above in ``Human Health'' section.
Rozman and Doull, 2005. Rozman and Doull, 2005. Presentation by Drs.
Rozman and Doull at the North American Congress of Clinical
Toxicologists. September 14, 2005. (EPA-HQ-OAR-2002-0064-0126)
RTI, 2005. Full citation above in ``Human Health'' section.
Ruckriegel, 2003. Comment on n-Propyl Bromide Recommended Workplace
Exposure Level in Proposed Rule Published in Federal Register Vol.
68, No. 106, June 3, 2003. August 2, 2003 (EPA-HQ-OAR-2002-0064-
0055)
Rusch and Bernhard, 2003. Comments on proposed regulation of n-
propyl bromide from Steven Bernhardt and George Rusch, Honeywell.
August 1, 2003. (EPA-HQ-OAR-2002-0064-0059)
Rusch, 2003. Late comments on proposed regulation of n-propyl
bromide from George Rusch, Honeywell. (EPA-HQ-OAR-2002-0064-0068)
Sekiguchi, 2002. Full citation above in ``Human Health'' section.
SLR International, 2001. Full citation above in ``Human Health''
section.
Smith, 2003. Comments on Protection of Stratospheric Ozone: Listing
of Substitutes for Ozone-Depleting Substances--n-Propyl Bromide, FR
Vol. 68, No. 106, June 3, 2003. R.L. Smith, Albemarle Corporation.
July 23, 2003. (EPA-HQ-OAR-2002-0064-0067)
Stelljes, 2003. Comments from Dr. Marc Stelljes, SLR International,
on proposed rule on n-propyl bromide. (HQ-EPA-OAR-2002-0064-0022)
Stelljes and Wood, 2004. Full citation above in ``Human Health''
section.
Stelljes, 2005. Full citation above in ``Human Health'' section.
TERA, 2004. Full citation above in ``Human Health'' section.
U.S. EPA, 1994b. Full citation above in ``Human Health'' section.
U.S. EPA, 1996. Full citation above in ``Human Health'' section.
U.S. EPA, 2003. Summary of Data on Workplace Exposure to n-Propyl
Bromide, May 21, 2003. EPA's summary of exposure data from nPB
suppliers and NIOSH. (EPA-HQ-OAR-2002-0064-0015 and -0016)
Weiss Cohen, 2003. Comments from Tammi Weiss Cohen, Dead Sea Bromine
Group. Comments To Federal Register Proposed Rules Of June 3, 2003,
On Protection Of Stratospheric Ozone: Listing Of Substitutes For
Ozone-Depleting Substances--N Propyl Bromide. (EPA-HQ-OAR-2002-0064-
0038)
Werner, 2003. Full citation above in ``Human Health'' section.
WIL, 2001. Full citation above in ``Human Health'' section.
Yamada et al., 2003. Full citation above in ``Human Health''
section.
Executive Orders and Statutes
Kassem, 2003. Full citation above for ``Decisions for Each Sector
and End Use'' section.
Ultronix, 2001. Response to questionnaire from EPA by C. Wolf,
Ultronix, 2001. (A-2001-07, II-D-76)
Tattersall, 2004. Conversation between M. Sheppard, EPA, and Tom
Tattersall, MicroCare Corporation. (EPA-HQ-OAR-2002-0064-0171)
[[Page 30167]]
U.S. EPA, 2003. Full citation above for ``Human Health'' section.
U.S. EPA, 2007. Analysis of Economic Impacts of Final nPB Rulemaking
for Cleaning Solvent Sector. 2007.
List of Subjects in 40 CFR Part 82
Environmental protection, Administrative practice and procedure,
Air pollution control, Reporting and recordkeeping requirements.
Dated: May 15, 2007.
Stephen L. Johnson,
Administrator.
Appendix A: Summary of Decision
Solvent Cleaning Acceptable Substitute
----------------------------------------------------------------------------------------------------------------
End uses Substitute Decision Further information
----------------------------------------------------------------------------------------------------------------
Metals cleaning, electronics n-propyl bromide (nPB) Acceptable............ EPA recommends the use of
cleaning, and precision cleaning. as a substitute for personal protective
CFC-113 and methyl equipment, including
chloroform. chemical goggles, flexible
laminate protective gloves
and chemical-resistant
clothing.
EPA expects that all users
of nPB would comply with
any final Permissible
Exposure Limit that the
Occupational Safety and
Health Administration
issues in the future under
42 U.S.C. 7610(a).
nPB, also known as 1-
bromopropane, is Number
106-94-5 in the Chemical
Abstracts Service (CAS)
Registry.
----------------------------------------------------------------------------------------------------------------
[FR Doc. E7-9707 Filed 5-29-07; 8:45 am]
BILLING CODE 6560-50-P