[Federal Register Volume 59, Number 189 (Friday, September 30, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-24251]


[[Page Unknown]]

[Federal Register: September 30, 1994]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 51

[FRL-4895-4]

 

Air Quality: Revision to Definition of Volatile Organic 
Compounds--Exclusion of Acetone

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The EPA is proposing to revise its definition of volatile 
organic compounds (VOC) for purposes of preparing State implementation 
plans (SIP's) to attain the national ambient air quality standards 
(NAAQS) for ozone under title I of the Clean Air Act (Act) and for the 
Federal implementation plan for the Chicago ozone nonattainment area. 
The proposed revision would add acetone to the list of compounds 
excluded from the definition of VOC on the basis that these compounds 
have negligible contribution to tropospheric ozone formation.

DATES: Comments on this proposal must be received by November 29, 1994.

ADDRESSES: Comments should be submitted in duplicate (if possible) to: 
Air and Radiation Docket and Information Center (6102), Attention: 
Docket No. A-94-26, U.S. Environmental Protection Agency, 401 M Street, 
SW., Washington, DC 20460. Comments should be strictly limited to the 
subject matter of this proposal, the scope of which is discussed below.
    Public Hearing: If anyone contacts EPA requesting a public hearing, 
it will be held at Research Triangle Park, North Carolina. Persons 
wishing to request a public hearing, wanting to attend the hearing or 
wishing to present oral testimony should notify Mr. William Johnson, 
Air Quality Management Division (MD-15), U.S. Environmental Protection 
Agency, Research Triangle Park, North Carolina 27711, telephone (919) 
541-5245. The EPA will publish notice of a hearing, if a hearing is 
requested, in the Federal Register. Any hearing will be strictly 
limited to the subject matter of the proposal, the scope of which is 
discussed below.
    This action is subject to the procedural requirements of section 
307(d)(1) (B), (J), and (U) of the Act, and 42 U.S.C. 7607(d)(1) (B), 
(J), and (U). Therefore, EPA has established a public docket for this 
action, A-94-26, which is available for public inspection and copying 
between 8 a.m. and 4 p.m., Monday through Friday, at EPA's Central 
Docket Section, room M-1500, 401 M Street, SW., Washington, DC 20460. A 
reasonable fee may be charged for copying.

FOR FURTHER INFORMATION CONTACT: William Johnson, Office of Air Quality 
Planning and Standards, Air Quality Management Division (MD-15), 
Research Triangle Park, NC 27711, phone (919) 541-5245.

SUPPLEMENTARY INFORMATION:

I. Background

    Three petitions have been received by the EPA asking that acetone 
be added to the list of negligibly-reactive compounds in the definition 
of VOC at 40 CFR 51.100(s). These petitions were submitted by Eastman 
Chemical Company and Hoechst Celanese Corporation on April 26, 1993, 
Hickory Springs Manufacturing Company on May 6, 1993, and the Chemical 
Manufacturers Association on May 14, 1993. Along with their petitions 
and in supplemental submissions, these organizations submitted a 
variety of scientific materials which support the assertion that 
acetone is of negligible photochemical reactivity. These materials have 
been added to the docket for this rulemaking.
    The petitioners based their request for the exclusion of acetone on 
a demonstration that the photochemical reactivity of acetone is not 
appreciably different from that of ethane, which is the most reactive 
compound on the current list of compounds which are named in the 
definition of VOC as being of negligible reactivity. Acetone's 
photochemical reactivity arises through two chemical pathways: through 
reaction with hydroxyl (OH) radicals (kOH reactivity) and through 
photolysis. Data on the reaction of OH radicals with various organic 
compounds are reported in a review article (Atkinson, R. (1990), 
``Gas--Phase Tropospheric Chemistry of Organic Compounds: A Review.'' 
Atmospheric Environment, 24 A:1-41) which gives the following rate 
constants for reactions of ethane and acetone with OH:

Ethane: 2.68 x 10-13 cc/molecule/sec.
Acetone: 2.26 x 10-13 cc/molecule/sec.

    Thus, if the kOH reactivities alone are considered, acetone is 
less reactive than ethane. Unlike ethane, however, acetone undergoes 
photodecomposition, or photolysis, in the atmosphere to form radicals, 
which tend to cause increased rates of ozone formation. Total 
reactivity of acetone, considering both kOH reactivity and 
photolysis, was the subject of a special study reported recently 
(Carter, W. P. L. et al., ``An Experimental and Modeling Study of the 
Photochemical Ozone Reactivity of Acetone,'' University of California/
Riverside, December 10, 1993).
    The Carter report describes a series of environmental chamber 
experiments and computer model simulations carried out to assess the 
tendency of acetone to promote ozone formation under atmospheric 
conditions, relative to that of ethane. This was done by calculating 
and comparing the ``incremental reactivities'' of acetone and ethane 
for a variety of atmospheric conditions representing ozone episodes in 
39 urban areas throughout the United States.
    ``Incremental reactivity'' is the most recently proposed 
quantitative measure of the degree to which a VOC contributes to ozone 
formation in a photochemical air pollution episode. It is defined as 
the amount of additional ozone formation resulting from the addition of 
a small amount of VOC to the urban emissions, divided by the amount of 
compound added. This measure of reactivity takes into account all of 
the factors by which a VOC affects ozone formation, including the 
effect of the environment where the VOC reacts. The latter is important 
because the amount of ozone formation caused by the reactions of a VOC 
depends significantly on the conditions within the polluted atmosphere, 
such as VOC to nitrogen oxide (NOX) ratio, VOC composition, and 
sunlight intensity. Figure 1 shows distribution plots of the reactivity 
of acetone relative to that of ethane for the 39 urban scenarios used, 
where reactivity is defined in terms of grams of ozone formed per gram 
of VOC emitted. (Use of the unit grams of ozone formed per gram of VOC 
emitted is significant. Another way of defining reactivity is in terms 
of grams of ozone formed per mole of VOC emitted, which would give 
different results. For practicality, the EPA has elected to adopt the 
grams ozone per gram VOC basis, since grams (or tons), rather than 
moles, is the mass unit used in regulations dealing with VOC 
emissions.) In Figure 1, acetone/ethane reactivity ratios less than 1.0 
indicate scenarios where acetone is less reactive than ethane. The 
acetone/ethane reactivity ratio, as reported by Carter, appears to have 
widely varying values among the 39 urban scenarios and to reflect, with 
a few exceptions, slightly lower reactivity for acetone. For one 
scenario, which represents unusually high NOX conditions, acetone 
was calculated to be over two times more reactive than ethane. This is 
due to the unusually low reactivity of ethane for that particular 
scenario, rather than to higher acetone reactivity. Figure 2 shows the 
variability of ethane reactivity relative to that of a ``typical'' 
urban VOC mix. Figure 2 also shows that the reactivity range of acetone 
falls entirely within the range for ethane.

BILLING CODE 6560-50-P

TP30SE94.002


TP30SE94.003


BILLING CODE 6560-50-C
    Although there are uncertainties in acetone's atmospheric photo-
oxidation mechanism and in the other aspects of ozone-related 
atmospheric photochemistry, one can reasonably deduce, based on the 
Carter report, that acetone and ethane probably have nearly the same 
reactivity for most sets of environmental conditions.
    Additional studies have been conducted on the relative reactivity 
of acetone in Europe. For example, R. G. Derwent and M. E. Jenkins 
(Hydrocarbons and the Long-range Transport of Ozone and PAN Across 
Europe, Atmospheric Environment, vol 24A, pp 1661-1678, 1991) used a 
chemical mechanism to calculate ozone impacts of acetone, ethane, and 
other VOC for three trajectories across Europe. The photochemical 
trajectory model the authors employed was developed at Harwell 
Laboratory (United Kingdom) and was used to calculate the photochemical 
ozone creation potential (POCP) values for 69 organic compounds, 
including acetone. The POCP values were assigned to VOC species 
according to a relative scale, with ethylene having a value of 100. Dr. 
Derwent reported in a letter (January 27, 1994) to EPA that: ``A 
comparison of POCP's for ethane and acetone in the work of my 
colleagues at Harwell Laboratory, which incidentally updates the 
acetone entries in the VOC Protocol Annex, gives 8.2  4.0 
and 9.2  2.0, respectively.'' The difference between these 
numbers is not considered to be statistically significant.
    If acetone is accepted as having negligible photochemical 
reactivity, exempting acetone from regulation as an ozone precursor 
could contribute to the achievement of several important environmental 
goals. For example, acetone can be used as a substitute for several 
compounds that are listed as hazardous air pollutants (HAP) under 
section 112 of the Act. Methylene chloride and methyl chloroform are 
HAP that are used for metal cleaning and for flexible polyurethane foam 
blowing. Other HAP, such as toluene, are often used as solvents in 
paints and coatings. Acetone can substitute for these substances in 
some circumstances.
    Acetone can also be used as a substitute for ozone depleting 
substances (ODS) which are active in depleting the stratospheric ozone 
layer. Under the London Amendments to the Montreal Protocol on 
substances that deplete the ozone layer (``Montreal Protocol''), the 
United States agreed to phase out production and consumption of certain 
chlorofluorocarbons (CFC) by the year 2000 and methyl chloroform by 
2005 (see 58 FR 15016 (March 18, 1993)). In 1990, Congress added title 
VI to the Act in part to provide for the implementation of this 
phaseout (see 42 U.S.C. 7671 et seq.). The 1990 Amendments specified an 
initial list of Class I and Class II ODS, authorizing EPA to add 
compounds to both lists depending on a given compound's potential to 
contribute to stratospheric ozone depletion, (Id. Sec. 7671a.) The 1990 
Amendments further required phaseout of the production and consumption 
of Class I ODS by 2000, methyl chloroform by 2002, and Class II ODS by 
2030 (see 42 U.S.C. 7671c, 7671d). At the fourth meeting, in 1992, of 
the parties to the Montreal Protocol in Copenhagen, Denmark, the 
parties adjusted the phaseout schedules for Class I substances under 
the Montreal Protocol to phase out Class I CFC and methyl chloroform by 
1996. In 1993, EPA proposed to accelerate the phaseout of Class I CFC 
and methyl chloroform in order to discontinue use of these compounds 
after January 1, 1996 (see 58 FR 15022).
    As a result of these phaseout deadlines, there is a need to develop 
substitutes for ODS. Allowing wider use of acetone will facilitate the 
transition away from ODS without adversely affecting efforts to control 
ground level ozone concentrations. For example, chlorofluorocarbon-11 
and methyl chloroform have been used as foam-blowing agents in the 
manufacture of polyurethane foam. These compounds are also used in 
metal cleaning in the aircraft manufacturing industry. Both CFC-11 and 
methyl chloroform are listed as Class I substances under title VI of 
the Act, i.e., as substances that have the highest stratospheric ozone- 
depleting potential. Acetone may be able to be used as a foam-blowing 
agent and cleaning agent in place of these chemicals.
    The EPA has already listed acetone as an acceptable ozone-depleting 
substance substitute under the program known as the ``Significant New 
Alternatives Policy'' (SNAP) program, (59 FR 13044, March 18, 1994). 
Within the context of the SNAP rule, substitutes are ``acceptable'' if 
they are technically feasible to be used as an alternative to an ODS 
for particular uses and give reduced overall risk to human health and 
the the environment compared to the ODS they replace. In the SNAP rule, 
EPA listed acetone as an acceptable substitute for flexible 
polyurethane foam blowing (59 FR 13132). The SNAP rule lists ketones 
(which include acetone) as an acceptable substitute for solvent 
cleaning in metal cleaning, electronics cleaning, and precision 
cleaning (59 FR 13134). Ketones are also listed in the SNAP rule as an 
acceptable substitute solvent for aerosols and for adhesives, coatings, 
and inks (59 FR 13145).
    In each of these areas of concern, toxic air emissions and 
depletion of stratospheric ozone, adding acetone to the list of 
negligibly-reactive VOC will support the EPA's pollution prevention 
efforts. By enacting the Pollution Prevention Act of 1990, Congress 
established as a national policy that ``pollution should be prevented 
or reduced at the source whenever feasible'' (42 U.S.C. 13). An 
important part of EPA's pollution prevention strategy is encouraging 
companies to use substitutes in their production processes that are 
more environmentally benign than the substances they currently use. For 
example, in its blueprint for a comprehensive national pollution 
prevention strategy, (56 FR 7849 (February 26, 1991)), the EPA 
recognized that the definition of pollution prevention includes a 
``switch to non-toxic or less toxic substitutes'' (Id. at 7854).
    National air emissions of acetone from industrial sources were 
estimated to be 80,000 tons per year in 1991. It should be noted that 
due to the high volatility of acetone, increased use of acetone for 
metal cleaning will most likely increase emissions of the compound to 
the air.

II. The EPA Response to the Petition

    Based on the scientific data presented in the material submitted by 
the petitioners, EPA accepts the conclusion that acetone is not 
appreciably different from ethane in terms of photochemical reactivity. 
The EPA is responding to the petitions by proposing in this notice to 
add acetone to the list of compounds appearing in 40 CFR 51.100(s) that 
are considered to be negligibly reactive and are thus excluded from the 
definition of VOC for ozone SIP and ozone control purposes. The revised 
definition will apply in the Chicago ozone nonattainment area pursuant 
to the 40 CFR 52.741(a)(3) definition of volatile organic material or 
volatile organic compound. States are not obligated to exclude from 
control as a VOC those compounds that EPA has found to be negligibly 
reactive. However, if this proposal is made final, EPA will not enforce 
measures controlling acetone as part of a federally-approved ozone SIP. 
In addition, once this proposal is made final, States should not 
include acetone in their VOC emissions inventories for determining 
reasonable further progress under the Act (e.g., section 182(b)(1)) and 
may not take credit for controlling acetone in their ozone control 
strategy. Further, after this proposal is made final, acetone may not 
be used for emissions netting (e.g., 40 CFR 51.166(b)(2)(c)), 
offsetting (40 CFR appendix S), or trading with reactive VOC (Emissions 
Trading Policy Statement, 51 FR 43814, December 4, 1986 and Economic 
Incentive Program Rules, 59 FR 16690, April 7, 1994).
    Since acetone will no longer be treated as a VOC, a State should 
revise its base year inventory and plans that rely on that inventory 
(e.g., the 15 percent plan) to remove acetone and the VOC emissions 
reduction credit taken from controlling acetone. To avoid unnecessary 
work, however, States may account for the fraction of the VOC inventory 
that acetone comprises or the amount of reduction claimed for 
controlling acetone. If the acetone fraction in the inventory or the 
amount of control claimed is not significant for a particular area, EPA 
would not expect a State to revise its emissions inventory or a plan 
based on that inventory to account for the revised VOC definition.
    In addition, corrections are made to the names of three compounds 
which have previously been exempted from the definition of VOC; 1,1,1-
trichloro-2,2,2-trifluoroethane (CFC-113) is changed to 1,1,2-
trichloro-1,2,2-trifluoroethane (CFC-113); chlorodifluoromethane (CFC-
22) is changed to chlorodifluoromethane (HCFC-22); and trifluoromethane 
(FC-23) is changed to trifluoromethane (HFC-23). These changes are 
corrections to nomenclature only and are not substantive.
    Pursuant to 5 U.S.C. 605(b), I hereby certify that this action will 
not have a significant economic impact on a substantial number of small 
entities because it relaxes current regulatory requirements rather than 
imposing new ones. The EPA has determined that this rule is not 
``significant'' under the terms of Executive Order 12866 and is, 
therefore, not subject to Office of Management and Budget (OMB) review. 
This action does not contain any information collection requirements 
subject to OMB review under the Paperwork Reduction Act of 1980 (44 
U.S.C. 3501 et seq.).
    Assuming this rulemaking is subject to section 317 of the Act, the 
Administrator concludes, weighing the Agency's limited resources and 
other duties, that it is not practicable to conduct an extensive 
economic impact assessment of today's action since this rule will relax 
current regulatory requirements. Accordingly, the Administrator simply 
notes that any costs of complying with today's action, any inflationary 
or recessionary effects of the regulation, and any impact on the 
competitive standing of small businesses, on consumer costs, or on 
energy use, will be less than or at least not more than the impact that 
existed before today's action.

List of Subjects in 40 CFR Part 51

    Administrative practice and procedure, Air pollution control, 
Carbon monoxide, Intergovernmental relations, Lead, Nitrogen dioxide, 
Ozone, Particulate matter, Reporting and recordkeeping requirements, 
Sulfur oxides, Volatile organic compounds.

    Dated: September 23, 1994.
Carol M. Browner,
Administrator.

    For reasons set forth in the preamble, part 51 of Chapter I of 
title 40 of the Code of Federal Regulations is proposed to be amended 
as follows:

PART 51--REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF 
IMPLEMENTATION PLANS

    1. The authority citation for part 51 continues to read as follows:

    Authority: 42 U.S.C. 7410(a)(2), 7475(e), 7502(a) and (b), 7503, 
7601(a)(1), and 7620.

    2. Section 51.100 is amended by revising paragraph (s)(1) 
introductory text to read as follows:


Sec. 51.100  Definitions.

* * * * *
    (s) * * *
    (1) This includes any such organic compound other than the 
following, which have been determined to have negligible photochemical 
reactivity: methane; ethane; methylene chloride (dichloromethane); 
1,1,1-trichloroethane (methyl chloroform); 1,1,2-trichloro-1,2,2-
trifluoroethane (CFC-113); trichlorofluoromethane (CFC-11); 
dichlorodifluoromethane (CFC-12); chlorodifluoromethane (HCFC-22); 
trifluoromethane (HFC-23); 1,2-dichloro 1,1,2,2-tetrafluoroethane (CFC-
114); chloropentafluoroethane (CFC-115); 1,1,1-trifluoro 2,2-
dichloroethane (HCFC-123); 1,1,1,2-tetrafluoroethane (HFC-134a); 1,1-
dichloro 1-fluoroethane (HCFC-141b); 1-chloro 1,1-difluoroethane (HCFC 
142b); 2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124); pentafluoroethane 
(HFC-125); 1,1,2,2-tetrafluoroethane (HFC-134); 1,1,1-trifluoroethane 
(HFC-143a); 1,1-difluoroethane (HFC-152a); acetone; and perfluorocarbon 
compounds which fall into these classes:
* * * * *
[FR Doc. 94-24251 Filed 9-29-94; 8:45 am]
BILLING CODE 6560-50-P