[Federal Register Volume 71, Number 159 (Thursday, August 17, 2006)]
[Proposed Rules]
[Pages 47670-47690]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-6927]



[[Page 47669]]

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Part V





Environmental Protection Agency





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40 CFR Part 63



 National Emission Standards for Hazardous Air Pollutants: Halogenated 
Solvent Cleaning; Proposed Rule

  Federal Register / Vol. 71, No. 159 / Thursday, August 17, 2006 / 
Proposed Rules  

[[Page 47670]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2002-0009, FRL-8210-3]
RIN 2060-AK22


National Emission Standards for Hazardous Air Pollutants: 
Halogenated Solvent Cleaning

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The EPA is proposing revised standards to limit emissions of 
methylene chloride (MC), perchloroethylene (PCE), and trichloroethylene 
(TCE) from existing and new halogenated solvent cleaning machines. In 
1994, EPA promulgated technology-based emission standards to control 
emissions of methylene chloride (MC), perchloroethylene (PCE), 
trichloroethylene (TCE), 1,1,1,-trichloroethane (TCA), carbon 
tetrachloride (CT), and chloroform from halogenated solvent cleaning 
machines. Pursuant to the Clean Air Act (CAA) section 112(f), EPA has 
evaluated the remaining risk to public health and the environment 
following implementation of the technology-based rule and is proposing 
more stringent standards in order to protect public health with an 
ample margin of safety. The proposed standards are expected to provide 
further reductions of MC, PCE, and TCE beyond the 1994 national 
emission standards for hazardous air pollutants (NESHAP), through 
application of a facility-wide total MC, PCE, and TCE emission 
standard. In addition, EPA has reviewed the standards as required by 
section 112(d)(6) of the CAA and has determined that, taking into 
account developments in practices, processes, and control technologies, 
no further action is necessary at this time to revise the national 
emission standards. The term ``facility-wide'' applies to facilities 
with emissions associated with halogenated solvent cleaning activities 
only.

DATES: Comments. Comments must be received on or before October 2, 
2006.
    Public Hearing. If anyone contacts EPA requesting to speak at a 
public hearing by August 28, 2006, a public hearing will be held 
approximately 15 days following publication of this notice in the 
Federal Register.

ADDRESSES: Comments. Submit your comments, identified by Docket ID No. 
EPA-HQ-OAR-2002-0009, by one of the following methods:
     http://www.regulations.gov. Follow the on-line 
instructions for submitting comments.
     E-mail: [email protected].
     Fax: (202) 566-1741.
     Mail: Air and Radiation Docket, EPA, Mailcode: 6102T, 1200 
Pennsylvania Ave., NW., Washington, DC 20460. Please include a 
duplicate copy, if possible. We request that a separate copy of each 
public comment also be sent to the contact person listed below (see FOR 
FURTHER INFORMATION CONTACT).
    Hand Delivery: Air and Radiation Docket, EPA, Room B-102, 1301 
Constitution Ave., NW., Washington, DC 20004. Such deliveries are only 
accepted during the Docket's normal hours of operation and special 
arrangements should be made for deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2002-0009. The EPA's policy is that all comments received will be 
included in the public docket without change and may be made available 
online at http://www.regulations.gov, including any personal 
information provided, unless the comment includes information claimed 
to be confidential business information (CBI) or other information 
whose disclosure is restricted by statute. Do not submit information 
that you consider to be CBI or otherwise protected through http://www.regulations.gov, or e-mail. The http://www.regulations.gov Web site 
is an ``anonymous access'' system, which means EPA will not know your 
identity or contact information unless you provide it in the body of 
your comment. If you send an e-mail comment directly to EPA without 
going through http://www.regulations.gov, your e-mail address will be 
automatically captured and included as part of the comment that is 
placed in the public docket and made available on the Internet. If you 
submit an electronic comment, EPA recommends that you include your name 
and other contact information in the body of your comment and with any 
disk or CD-ROM you submit. If EPA cannot read your comment due to 
technical difficulties and cannot contact you for clarification, EPA 
may not be able to consider your comment. Electronic files should avoid 
the use of special characters, any form of encryption, and be free of 
any defects or viruses.
    Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
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 B-102, 1301 Constitution Ave., NW., 
Washington, DC. The Public Reading Room 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.
    Public Hearing: If a public hearing is held, it will be held at 10 
a.m. at EPA's Environmental Research Center Auditorium, Research 
Triangle Park, NC, or at an alternate site nearby.

FOR FURTHER INFORMATION CONTACT: Mr. H. Lynn Dail, Natural Resources 
and Commerce Group (E143-03), Sector Policies and Programs Division, 
EPA, Research Triangle Park, NC 27711; telephone number (919) 541-2363; 
fax number (919) 541-3470, e-mail address: [email protected]. For 
questions on the residual risk analysis, contact Mr. Dennis Pagano, 
Sector Based Assessment Group (C539-02), Health and Environmental 
Impacts Division, EPA, Research Triangle Park, NC 27711; telephone 
(919) 541-0502; fax number (919) 541-0840, e-mail address: 
[email protected].

SUPPLEMENTARY INFORMATION:
    Regulated Entities. The categories and entities potentially 
regulated by the proposed rule include:

[[Page 47671]]



------------------------------------------------------------------------
                                                         Examples of
          Category               NAICS \1\ code          potentially
                                                     regulated entities
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Industry....................  Any of numerous       Operations at
                               industries using      sources that are
                               halogenated solvent   engaged in solvent
                               cleaning, primary     cleaning using MC,
                               affected industries   PCE, or TCE.
                               include those in
                               NAICS Codes
                               beginning with: 331
                               (primary metal
                               man.), 332
                               (fabricated metal
                               man.), 333
                               (machinery man.),
                               334 (computer and
                               electronic product
                               man.), 335
                               (electrical
                               equipment,
                               appliance, and
                               component man.);
                               336 (transportation
                               equipment man.);
                               337 (furniture and
                               related products
                               man.); and 339
                               (misc. man.).
Federal, State, local, and    ....................  Operations at
 tribal government.                                  sources that are
                                                     engaged in solvent
                                                     cleaning using MC,
                                                     PCE, or TCE.
------------------------------------------------------------------------
\1\ North American Industry Classification System.

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be affected by the 
proposed rule. This proposal directs an owner or operator of 
halogenated solvent cleaning facilities to determine if whether the 
applicability criteria in 40 CFR 63.460 of subpart T (1994 national 
emission standards for Halogenated Solvent Cleaning) remains or whether 
these proposed standards require the facility to operate under the 
emission caps set forth. If you have any questions regarding the 
applicability of the proposed standards to a particular entity, consult 
the person listed in the preceding FOR FURTHER INFORMATION CONTACT 
section.
    Submitting CBI. Do not submit this information to EPA through 
http://www.regulations.gov or e-mail. Clearly mark the part or all of 
the information that you claim to be CBI. For CBI information on a disk 
or CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM 
as CBI and then identify electronically within the disk or CD-ROM the 
specific information that is claimed as CBI. In addition to one 
complete version of the comment that includes information claimed as 
CBI, a copy of the comment that does not contain the information 
claimed as CBI must be submitted for inclusion in the public docket. 
Information so marked will not be disclosed except in accordance with 
procedures set forth in 40 CFR part 2.
    Public Hearing. Persons interested in presenting oral testimony or 
inquiring as to whether a public hearing is to be held should contact 
Ms. Dorothy Apple, Natural Resources and Commerce Group (E143-03), 
Sector Policies and Programs Division, EPA, Research Triangle Park, NC 
27711, telephone number: (919) 541-4487, e-mail address: 
[email protected] , at least 2 days in advance of the potential 
date of the public hearing. Persons interested in attending the public 
hearing also must call Ms. Apple to verify the time, date, and location 
of the hearing. A public hearing will provide interested parties the 
opportunity to present data, views, or arguments concerning the 
proposed standards.
    Worldwide Web (WWW). In addition to being available in the docket, 
an electronic copy of the proposed rule is also available on the WWW 
through the Technology Transfer Network (TTN). Following signature, a 
copy of the proposed rule will be posted on the TTN's policy and 
guidance page for newly proposed or promulgated rules at http://www.epa.gov/ttn/oarpg. The TTN provides information and technology 
exchange in various areas of air pollution control.
    Outline. The information presented in this preamble is organized as 
follows:

I. Background
    A. What is the statutory authority for regulating hazardous air 
pollutants (HAP)?
    B. What is halogenated solvent cleaning?
    C. What are the health effects of halogenated solvents?
    D. What does the 1994 halogenated solvent cleaning NESHAP 
require?
II. Summary of Proposed Requirements for New and Existing Major and 
Area Sources
III. Rationale for the Proposed Rule
    A. What is our approach for developing residual risk standards?
    B. How did we estimate residual risk?
    1. How did we estimate the emission and stack parameters for 
these sources?
    2. How did we estimate the atmospheric dispersion of the emitted 
pollutants?
    3. How were cancer and non-cancer risks estimated?
    4. What factors are considered in the risk assessment?
    C. What are the results of the baseline risk assessment?
    D. What is our proposed decision on acceptable risk?
    E. What is our proposed decision on ample margin of safety?
    1. What risk reduction alternatives did EPA evaluate?
    2. What are the costs of the proposed alternatives?
    3. What regulatory options is EPA proposing?
    4. Rationale for Option 1
    5. Rationale for Option 2
    6. Comparison of Option 1 and 2
    F. What is EPA proposing pursuant to CAA Section 112(d)(6)?
    G. What is the rationale for the proposed compliance schedule?
IV. Solicitation of Public Comments
    A. Introduction and General Solicitation
V. 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 Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act

I. Background

A. What is the statutory authority for regulating hazardous air 
pollutants (HAP)?

    Section 112 of the CAA establishes a two-stage regulatory process 
to address emissions of hazardous air pollutants (HAP) from stationary 
sources. In the first stage, CAA section 112(d) calls for us to 
promulgate national technology-based emission standards for categories 
of sources that emit or have the potential to emit any single HAP at a 
rate of 10 tons or more per year or any combination of HAP at a rate of 
25 tons or more per year (known as ``major sources''), as well as for 
certain ``area sources'' emitting less than those amounts. For major 
sources, these technology-based standards must reflect the maximum 
reductions of HAP achievable (after considering cost, energy 
requirements, and non-air health and environmental impacts) and are 
commonly referred to as maximum achievable control technology (MACT) 
standards.
    For area sources, CAA section 112(d)(5) provides that the standards

[[Page 47672]]

may reflect generally available control technology or management 
practices in lieu of MACT, and are commonly referred to as generally 
available control technology (GACT) standards.
    CAA section 112(d)(6) then requires EPA to review these technology-
based standards and to revise them ``as necessary, taking into account 
developments in practices, processes and control technologies,'' no 
less frequently than every 8 years.
    The second stage in standard-setting is described in section 112(f) 
of the CAA. EPA prepared a Report to Congress discussing (among other 
things) methods of calculating risk posed (or potentially posed) by 
sources after implementation of the MACT standards, the public health 
significance of those risks, the means and costs of controlling them, 
actual health effects to persons in proximity to emitting sources, and 
recommendations as to legislation regarding such remaining risk. The 
EPA prepared and submitted this report (``Residual Risk Report to 
Congress,'' EPA-453/R-99-001) in March 1999. The Congress did not act 
on any of the recommendations in the report; thereby, triggering the 
second stage of the standard-setting process, the residual risk phase.
    CAA section 112(f)(2) requires us to determine for each CAA section 
112(d) source category whether the MACT standards protect public health 
with an ample margin of safety. If the MACT standards for HAP 
``classified as a known, probable, or possible human carcinogen do not 
reduce lifetime excess cancer risks to the individual most exposed to 
emissions from a source in the category or subcategory to less than 1-
in-a-million,'' EPA must promulgate residual risk standards for the 
source category (or subcategory) as necessary to provide an ample 
margin of safety. The EPA must also adopt more stringent standards to 
prevent an adverse environmental effect (defined in CAA section 
112(a)(7) as ``any significant and widespread adverse effect * * * to 
wildlife, aquatic life, or natural resources * * *.''), but must 
consider cost, energy, safety, and other relevant factors in doing so.

B. What is halogenated solvent cleaning?

    Halogenated solvent cleaning machines use halogenated solvents 
(methylene chloride, perchloroethylene, trichloroethylene, 1,1,1,-
trichloroethane, carbon tetrachloride, and chloroform), halogenated 
solvent blends, or their vapors to remove soils such as grease, oils, 
waxes, carbon deposits, fluxes, and tars from metal, plastic, 
fiberglass, printed circuit boards, and other surfaces. Halogenated 
solvent cleaning is typically performed prior to processes such as 
painting, plating, inspection, repair, assembly, heat treatment, and 
machining. Types of solvent cleaning machines include, but are not 
limited to, batch vapor, in-line vapor, in-line cold, and batch cold 
solvent cleaning machines. Buckets, pails, and beakers with capacities 
of 7.6 liters (2 gallons) or less are not considered solvent cleaning 
machines.
    Halogenated solvent cleaning does not constitute a distinct 
industrial category, but is an integral part of many major industries. 
The five 3-digit NAICS Code that use the largest quantities of 
halogenated solvents for cleaning are NAICS 337 (furniture and related 
products manufacturing), NAICS 332 (fabricated metal manufacturing), 
NAICS 335 (electrical equipment, appliance, and component 
manufacturing), NAICS 336 (transportation equipment manufacturing), and 
NAICS 339 (miscellaneous manufacturing). Additional industries that use 
halogenated solvents for cleaning include NAICS 331 (primary metals), 
NAICS 333 (machinery), and NAICS 334 (electronic equipment 
manufacturing). Non-manufacturing industries such as railroad (NAICS 
482), bus (NAICS 485), aircraft (NAICS 481), and truck (NAICS 484) 
maintenance facilities; automotive and electric tool repair shops 
(NAICS 811); and automobile dealers (NAICS 411) also use halogenated 
solvent cleaning machines. We estimated that there were approximately 
16,400 batch vapor, 8,100 in-line, and perhaps as many as 100,000 batch 
cold cleaning machines in the U.S. prior to promulgation of the MACT 
standards. More recent information shows that the current number of 
cleaning machines is much lower than these pre-MACT estimates. We 
currently estimate the number of sources in this source category to be 
about 3,800 cleaning machines located at 1,900 facilities in the U.S. 
This estimate is based on information we collected in 1998, a year 
after compliance with the MACT occurred, and should reflect the 
decreases in HAP emissions and demand that were expected due to 
implementation of MACT control technologies and work practice 
standards. Recent evidence on solvent usage suggests that the number of 
sources in the source category may have declined further in the post-
MACT implementation years. An analysis of market data for halogenated 
solvents showed that the demand for degreasing solvents declined 
substantially in the 5 years following the implementation of MACT. From 
1998 to 2003, the demand for PCE, TCE, MC, and TCA for degreasing 
decreased by 39 percent, 35 percent, 23 percent, and 15 percent, 
respectively. The halogenated solvents carbon tetrachloride and 
chloroform are no longer used in this source category. The Montreal 
Protocol, a treaty signed on September 16, 1987, phased-out the 
production and consumption of these chlorofluorocarbons by January 1, 
1996. The Protocol also phased out TCA. TCA has not been manufactured 
for domestic use in the United States since January 1, 2002. Facilities 
with essential products or activities are allowed to continue their use 
of TCA, but for facilities with non-essential activities or products, 
they were allowed to use remaining TCA stockpiles until depleted.
    There are two basic types of solvent cleaning machines: Batch 
cleaners and in-line cleaners. Both cleaner types can be designed to 
use either solvent at room temperature (cold cleaners) or solvent vapor 
(vapor cleaners). The vast majority of halogenated solvent use is in 
vapor cleaning, both batch and in-line. The most common type of batch 
cleaner that uses halogenated solvent is the open-top vapor cleaner 
(OTVC).
    Batch cleaning machines, which are the most common type, are 
defined as a solvent cleaning machine in which individual parts or sets 
of parts move through the entire cleaning cycle before new parts are 
introduced. Batch cleaning machines include cold and vapor machines. In 
batch cold cleaning machines, the material being cleaned (i.e., the 
workload) is immersed, flushed, or sprayed with liquid solvent at room 
temperature. Most batch cold cleaners are small maintenance cleaners 
(e.g., carburetor cleaners) or parts washers that often use non-HAP 
solvent mixtures for cleaning. Batch cold cleaning equipment sometimes 
includes agitation to improve cleaning efficiency.
    In batch vapor cleaning machines, parts are lowered into an area of 
dense vapor solvent for cleaning. The most common type of batch vapor 
cleaner is the open-top vapor cleaner. Heating elements at the bottom 
of the cleaner heat the liquid solvent to above its boiling point. 
Solvent vapor rises in the machine to the height of chilled condensing 
coils on the inside walls of the cleaner. The condensing coils cool the 
vapor causing it to condense and return to the bottom of the cleaner. 
Cleaning occurs in the vapor zone above the liquid solvent and below 
the condensing coils, as the hot vapor solvent condenses on the cooler

[[Page 47673]]

workload surface. The workload or a parts basket is lowered into the 
heated vapor zone with a mechanical hoist.
    Batch vapor cleaning machines vary greatly in size and design to 
suit applications in many industries. Batch vapor cleaner sizes are 
defined by the area of the solvent/air interface.
    Emissions from batch cold cleaning machines result from evaporation 
of solvent from the solvent/air interface ``carry out'' of excess 
solvent on cleaned parts, and other evaporative losses such as those 
that occur during filling and draining. Evaporative emissions from the 
solvent/air interface are continual whether or not the machine is in 
use. These evaporative losses can be reduced by limiting air movement 
over the solvent/air interface (e.g., with a machine cover or by 
reducing external drafts) or by limiting the area of solvent air 
interface (e.g., with a floating water layer). Emissions related to 
solvent carry out occur only when the cleaning machine is in use. Carry 
out emissions may be substantial, especially if excess solvent is not 
allowed to drain back into the machine. Carry out includes solvent film 
remaining on flat workload surfaces and liquid pooled in cavities. 
Factors affecting the amount of carry out loss include the speed of 
parts movement, workload shapes and materials, and work practices 
(e.g., turning over parts to drain cavities).
    The closed-loop cleaning system is a type of batch cleaner with a 
closed system capable of reusing solvent. Parts are placed inside a 
vacuum chamber. Vapor or liquid solvent is pumped in the chamber to 
clean the parts. Once cleaned, the parts are dried under vacuum and 
removed; the solvent is removed and recycled. Because these systems are 
constructed to maintain a vacuum, they have the potential to reduce 
emissions up to 97 percent.
    Cold and vapor in-line (i.e., conveyorized) cleaning machines, 
which include continuous web cleaners, employ automated parts loading 
and are used in applications where there is a constant stream of parts 
to be cleaned. In-line cleaners usually are used in large-scale 
industrial operations (e.g., auto manufacturing) and are custom-
designed for specific workload and production characteristics (e.g., 
workload size, shape, and production rate). In-line cleaners clean 
parts using the same general techniques used in batch cleaners: cold 
in-line cleaners spray or immerse parts in solvent, and vapor in-line 
cleaners clean parts in a zone of dense vapor solvent.
    Emissions from cold and vapor in-line cleaning machines result from 
the same mechanisms (e.g., evaporation, diffusion, carryout) that cause 
emissions from cold and vapor batch cleaning machines. However, the 
emission points for in-line cleaners are different from those for batch 
cleaners because of differences in machine configurations. In-line 
cleaning machines are semi-enclosed above the solvent/air interface to 
control solvent losses. In most cases, the only openings are the parts 
entry and exit ports. These openings are the only emissions points for 
downtime and idling modes. Carryout emissions add to emissions during 
the working mode. Idling and working mode emissions from the in-line 
cleaner are significantly less than emissions from an equally-sized 
batch vapor cleaner. However, in-line cleaners tend to be much larger 
than batch vapor cleaners. Some in-line cleaners have exhaust systems 
that pump air from inside the cleaning machine to an outside vent. 
Exhaust systems for in-line cleaners reduce indoor emissions from the 
cleaning machine but increase solvent consumption.
    Continuous cleaners are a subset of in-line cleaners and are used 
to clean products such as films, sheet metal, and wire in rolls or 
coils. The workload is uncoiled and conveyorized throughout the 
cleaning machine at speeds in excess of 11 feet per minute and recoiled 
or cut as it exits the machine. Emission points from continuous 
cleaners are similar to emission points from other inline cleaners. 
Continuous cleaners are semi-enclosed, with emission points where the 
workload enters and exits the machine. Squeegee rollers reduce carry 
out emissions by removing excess solvent from the exiting workload. 
Some continuous machines have exhaust systems similar to those used 
with some other in-line cleaners.

C. What are the health effects of halogenated solvents?

    Methylene chloride, perchloroethylene, 1,1,1,-trichloroethylene 
(TCA), and trichloroethylene are the primary halogenated solvents used 
for solvent cleaning. Carbon tetrachloride and chloroform are no longer 
used as degreasing solvents. Therefore, their health effects are not 
discussed in this section. The four solvents still in use are described 
below. All four produce acute and/or chronic non-cancer health effects 
at sufficient concentrations; three of the four have been classified as 
probable or possible human carcinogens by either EPA or other 
governmental or international agencies.
    Methylene chloride is predominantly used as a solvent. The acute 
effects of methylene chloride inhalation in humans consist mainly of 
central nervous system effects including decreased visual, auditory, 
and motor functions that may occur at or above 1-hour exposures of 690 
mg/m\3\, but these effects are reversible once exposure ceases. The 
effects of chronic exposure to methylene chloride suggest that the 
central nervous system is a potential target in humans and animals. 
ATSDR estimates that no adverse noncancer effects are likely in human 
populations chronically exposed at or below 1 mg/m3. Human 
studies are inadequate regarding methylene chloride and cancer. 
However, animal studies have shown significant increases in liver and 
lung cancer and benign mammary gland tumors following the inhalation of 
methylene chloride. On this basis, EPA classified methylene chloride as 
a Group B2, probable human carcinogen, with a cancer unit risk estimate 
(URE) of 4.7 x 10-7 ([mu]g/m\3\)-1, when assessed 
under the previous 1986 Cancer Guidelines. EPA is currently reassessing 
its potential toxicity and carcinogenicity. All activities related to 
this chemical reassessment are expected to be complete in late 2007.
    Perchloroethylene (PCE or tetrachloroethylene) is widely used for 
dry-cleaning fabrics and metal degreasing operations. The main effects 
of PCE in humans are neurological, liver, and kidney damage following 
acute (short-term) and chronic (long-term) inhalation exposure. The 
results of epidemiological studies evaluating the relative risk of 
cancer associated with PCE exposure have been mixed; some studies 
reported an increased incidence of a variety of tumors, while other 
studies did not report any carcinogenic effects. Animal studies have 
reported an increased incidence of liver cancer in mice, via inhalation 
and gavage (experimentally placing the chemical in the stomach), and 
kidney and mononuclear cell leukemia in rats.
    Although PCE has not yet been reassessed under the Agency's 
recently revised Guidelines for Cancer Risk assessment, it was 
considered in one review by the EPA's Science Advisory Board to be 
intermediate between a ``probable'' and ``possible'' human carcinogen 
(Group B/C) when assessed under the previous 1986 Guidelines. Since 
that time, the U.S. Department of Health and Human Services has 
concluded that PCE is ``reasonably anticipated to be a human 
carcinogen,'' and the International Agency for Research on Cancer has 
concluded that PCE is ``probably carcinogenic to humans.''

[[Page 47674]]

    Effects other than cancer associated with long-term inhalation of 
PCE in worker or animal studies include neurotoxicity, liver and kidney 
damage, and, at higher levels, developmental effects. To characterize 
noncancer hazard in lieu of the completed Integrated Risk Information 
System (IRIS) assessment, which is being revised, we used the Agency 
for Toxic Substances and Disease Registry's (ATSDR) Minimum Risk Level 
(MRL). This value is based on a study of neurological effects in 
workers in dry cleaning shops, and is derived in a manner similar to 
EPA's method for derivation of reference concentrations, including 
scientific and public review. Based on these effects, EPA estimates 
that no adverse noncancer effects are likely in human populations 
chronically exposed at or below 0.27 mg/m\3\.
    The Agency's IRIS chemical assessment for PCE is currently being 
revised. The current schedule indicates that a final IRIS determination 
on PCE is not expected until 2008 at the earliest. Because EPA has not 
yet issued a final IRIS document for PCE, to estimate cancer risk, we 
used the California EPA (CalEPA) unit risk estimate (URE) of 5.9 x 
10-6 (ug/m\3\)-1, as well as a URE value 
developed by the EPA's Office of Prevention, Pesticides and Toxic 
Substances (OPPTS) of 7.1 x 10-7 (ug/m\3\)-1. The 
final IRIS reassessment may result in a URE that is different from 
these two values. Among the available Acute Reference Levels (ARL), the 
one-hour California Reference Exposure Level (a REL value of 240 mg/
m\3\) was considered the most appropriate to use in the assessment 
because it may be used to characterize acute risk for exposure with an 
exposure duration of one hour.
    Most of the trichloroethylene (TCE) used in the United States is 
released into the atmosphere from industrial degreasing operations. 
Acute and chronic inhalation exposure to trichloroethylene can affect 
the human central nervous system, with symptoms such as dizziness, 
headaches, confusion, euphoria, facial numbness, and weakness. Liver, 
kidney, immunological, endocrine, and developmental effects have also 
been reported in humans. Acute effects may occur at or above 1-hour 
exposures of 700 mg/m\3\. CalEPA estimates that no adverse noncancer 
effects are likely in human populations chronically exposed at or below 
0.6 mg/m\3\. Animal studies have reported statistically significant 
increases in kidney, lung, liver, and testicular tumors. EPA classified 
trichloroethylene in Group B2/C, an intermediate between a probable and 
possible human carcinogen, when assessed under the previous 1986 Cancer 
Guidelines, but this classification has been withdrawn. CalEPA has 
derived a cancer URE of 2.0 x 10-6 (ug/m\3\)-1 
for TCE, which we used for our cancer risk assessment. EPA is currently 
reassessing the cancer classification of trichloroethylene.
    In 1999, TCA was used as a solvent for degreasing up until it was 
phased out in 2002. CalEPA estimates that no adverse noncancer effects 
are likely in human populations chronically exposed to TCA at or below 
1 mg/m\3\. EPA classified TCA in Group D, not classifiable as to human 
carcinogenicity, when assessed under the previous 1986 Cancer 
Guidelines. EPA is currently reassessing its potential toxicity 
(related to chronic and less-than-lifetime exposures). All activities 
related to chemical reassessment are expected to be complete in 2007. 
Although production and use of TCA has been phased-out since 1998, a 
declining quantity of TCA continued to be used until 2002, when all 
production of TCA ceased, and eventually, facilities used TCA stock-
piles until depleted. However, an exemption to the phase-out allows a 
few specialized facilities with essential activities or products to 
continue its use of TCA. TCA was profiled in the noncancer chronic risk 
assessment.
    The OPPTS toxicity profile for perchloroethylene (PCE) is published 
in an EPA publication entitled, Cleaner technologies substitutes 
assessment: professional fabricare processes. U.S. EPA Office of 
Pollution Prevention and Toxics, Washington DC. EPA 744-B-98-001; June 
1998. Complete toxicity profiles for the four HAPs may be obtained from 
the following Web sites: EPA's OPPTS Web site for perchloroethylene at 
http://www.epa.gov/dfe/pubs/garment/ctsa/fabricare.pdf; California 
EPA's Web site at http://www.oehha.ca.gov/air/hot_spots/index.html; 
and the Agency for Toxic Substances and Disease Registry's Web site at 
http://www.atsdr.cdc.gov/toxpro2.html. Status reports for IRIS chemical 
reassessments are available at http://cfpub.epa.gov/iristrac/index.cfm.

D. What does the 1994 halogenated solvent cleaning NESHAP require?

    We promulgated national emission standards for halogenated solvent 
cleaning (59 FR 61805, December 2, 1994) and required existing sources 
to comply with the national emission standards by December 2, 1996. The 
halogenated solvent cleaner NESHAP requires batch vapor solvent 
cleaning machines and in-line solvent cleaning machines to meet 
emission standards reflecting the application of the maximum achievable 
control technology for major and area sources; area source batch cold 
cleaning machines are required to achieve generally available control 
technology. The rule regulates the emissions of the following 
halogenated HAP solvents: MC, PCE, TCE, TCA, CT, and chloroform. In 
1999, MC, PCE, TCE and TCA were the primary halogenated solvents used 
for solvent cleaning. Although production and use of TCA has been 
phased-out since 1998, a declining quantity of TCA continued to be used 
until 2002, with either facilities depleting existing stockpiles past 
2002 or facilities with essential products or activities continuing use 
of TCA. CT and chloroform are no longer used as degreasing solvents.
    The promulgated standard includes multiple alternatives to allow 
owners or operators maximum compliance flexibility. These alternatives 
include:
     Control equipment standards--As many as 10 combinations of 
emission control equipment, such as freeboard refrigeration devices and 
working-mode covers may be installed.
     Idling-mode emissions standards--Compliance may be 
demonstrated by maintaining monthly emission rates during the idling 
mode below specified standards.
     Overall emission standards--Solvent use and disposal 
records may be used to calculate average monthly emissions, which must 
remain below specified numerical limits.
    If an owner or operator of a batch vapor or in-line cleaning 
machine elects to comply with the equipment standard, they must install 
one of the control combinations listed in the regulation, use an 
automated parts handling system to process all parts, and follow 
multiple work practices. As an alternative to selecting one of the 
equipment control combinations listed in the regulation, an owner or 
operator may demonstrate that the batch vapor or in-line cleaning 
machine can meet the idling mode emission limit specified in the 
standards. In addition to maintaining this idling mode emission limit, 
the owner or operator of a batch vapor or in-line solvent cleaning 
machine must use an automated parts handling system to process all 
parts and comply with the work practice standards. A third alternative 
for complying with these standards is to comply with the overall 
solvent emissions limit. An owner or operator complying with the 
overall solvent emissions limit is required to ensure that the 
emissions from each

[[Page 47675]]

solvent cleaning machine are less than or equal to the solvent emission 
levels specified in the standard. Under this alternative standard, an 
owner or operator is not required to use an automated parts handling 
system or to comply with the work practice standards.
    The batch cold cleaning machine standard is an equipment standard. 
However, those owners or operators choosing the equipment options 
without the water layer must also comply with work practice 
requirements. There is no idling standard or overall solvent emissions 
standard for batch cold cleaning machines. Batch cold cleaning machines 
located at non-major sources are exempt from Title V permit 
requirements.
    The halogenated solvent cleaning NESHAP was estimated to reduce 
nationwide emissions of hazardous air pollutants (HAP) from halogenated 
solvent cleaning machines by 77,400 Mg/yr (85,300 tons per year) or 63 
percent by 1997 compared to the emissions that would result in the 
absence of the standards.

II. Summary of the Proposed Requirements for New and Existing Major and 
Area Sources

    Under the proposed standards, the requirements for all new and 
existing, major and area sources are the same. In addition to the MACT 
standard, the proposed revisions would require each facility to comply 
with a facility-wide solvent emission limit. As defined by this 
proposed rule, ``facility-wide solvent emissions'' are the combined 
emissions of PCE, TCE, and MC from all of a facility's solvent cleaning 
machines that are subject to the 1994 MACT standards (40 CFR Part 63, 
subpart T). Under CAA section 112(f), EPA has the discretion to impose 
residual risk standards on area sources regulated under generally 
available control technologies (GACT). The area sources subject to GACT 
in the halogenated solvent cleaning source category would not be 
subject to today's proposed standards. These sources are cold batch 
cleaners.
    The proposed rule would require the owner or operator of each 
facility to ensure that their facility-wide solvent emissions from all 
halogenated solvent cleaning activities are less than or equal to the 
solvent emission limits specified in the proposed options and 
summarized in Table 1 of this preamble. This approach gives the owner 
or operator of the facility the flexibility to choose any means of 
reducing the facility-wide emissions of PCE, TCE, and MC to comply with 
facility-wide emission limit. The proposed options are in addition to 
the existing NESHAP requirements and, therefore, all requirements of 
the existing NESHAP remain in place.
    Table 1 shows two sets of facility-wide emission limits--option 1 
and option 2. We are co-proposing both of these options and are 
soliciting comment on which of these two options is most appropriate. 
As can be seen in Table 1 of this preamble, each halogenated solvent 
has an associated facility-wide emission limit. These limits are for 
facilities that emit only a single halogenated solvent. If more than 
one halogenated solvent is used, the owner or operator of the facility 
must calculate the facility's weighted halogenated solvent cleaning 
emissions using equation 1 and comply with the limit in the last row of 
Table 1 of this preamble. Note that, depending on whether the CalEPA 
URE or the OPPTS URE for PCE is used to derive the PCE limit, that 
limit may be lower or higher. We request comment on the use of the 
CalEPA URE, the OPPTS URE, or some other value in deriving the PCE 
emission limit for the final rule.

 Table 1.--Summary of the Proposed Facility-Wide Annual Emission Limits
------------------------------------------------------------------------
                                  Proposed facility-  Proposed facility-
                                      wide annual         wide annual
        Solvents emitted          emission limits in  emission limits in
                                     kg--option 1        kg--option 2
------------------------------------------------------------------------
PCE only........................       \a\ 3,200 \b\       \a\ 2,000 \b\
                                            (26,700)            (16,700)
TCE only........................              10,000               6,250
MC only.........................              40,000              25,000
Multiple solvents--Calculate the              40,000             25,000
 MC-weighted emissions using
 equation 1.....................
------------------------------------------------------------------------
\a\ PCE emission limit calculated using CalEPA URE.
\b\ PCE emission limit calculated using OPPTS URE.

Equation 1:

    (kgs of PCE emissions x A) + (kgs of TCE emissions x B) + (kgs of 
MC emissions) = Weighted Emissions in kgs

    We developed a method for facilities using multiple HAP solvents to 
determine their emission limit by calculating their MC-equivalent 
emissions using the toxicity-weighted equation above. In the equation, 
the facility emissions of PCE and TCE are weighted according to their 
carcinogenic potency relative to that of MC. Thus, ``A'' in the 
equation is the ratio of the URE for PCE to the URE for MC, and the 
``B'' in the equation is the ratio of the URE for TCE to the URE for 
MC. The value of ``A'' is either 1.5 or 12.5, depending on whether we 
use the OPPTS URE or the CalEPA URE for PCE. The value for ``B'' is 
4.25. We believe there may be other approaches to arriving at emissions 
alternatives for multiple HAP use and we request comment on the use of 
the MC-equivalency method, or other possible calculation methods that 
we should consider, when establishing emission limits for facilities 
using more than one of the listed HAP solvents. We also request comment 
on whether the OPPTS URE, the CalEPA URE or some other value should be 
used in the implementation of the emission cap chosen for the final 
rule.
    Compliance with the emission limit is demonstrated by determining 
the annual PCE, TCE, and MC emissions for all cleaning machines at the 
facility. There is no additional equipment monitoring or work practice 
requirements associated with the facility-wide annual emissions limit. 
Annual emissions of these HAP are determined based on records of the 
amounts and dates of the solvents added to cleaning machines during the 
year, the amounts and dates of solvents removed from cleaning machines 
during the year, and the amounts and dates of the solvents removed from 
cleaning machines in solid waste. Records of the calculation sheets 
showing how the annual emissions were determined must be maintained. A 
facility will determine compliance with the standards by

[[Page 47676]]

comparing their annual MC-equivalent emissions versus the level in the 
final rule.
    We believe owners and operators currently have information 
available to immediately determine if they would be in compliance with 
today's proposed emissions limits. Current recordkeeping requirements 
in 40 CFR subpart T section 63.467 require each owner and operator of 
solvent cleaning machines to maintain, for 5 years, estimates of 
solvent content and annual solvent consumption for each solvent 
cleaning machine and any calculations showing how monthly emissions or 
3-month rolling average emissions were calculated. Moreover, current 
reporting requirements in 40 CFR subpart T Section 63.468 include an 
initial notification report, an initial statement of compliance report, 
annual compliance reports, and an exceedance report (required only when 
an exceedance occurs). In the initial notification report, owners and 
operators disclose an estimate of the annual halogenated HAP solvent 
consumption for each solvent cleaning machine. Furthermore, owners and 
operator submit annual reports that contain estimates of their solvent 
consumption for each solvent cleaning machine used during the period.
    We believe that there are multiple ways in which facilities could 
comply with the proposed rule. Our analysis also shows that some 
affected facilities can easily reduce emissions and risks through 
solvent switching. Solvent switching, in this case, is switching from a 
high risk solvent to one with lower health risks. Facilities can also 
reduce emissions by reducing solvent use, and by using careful work 
practices and traditionally available control options to further reduce 
emissions. Increased diligence in controlling lids, installing 
freeboard chillers, increased drying times, installing closed loop 
systems, and increasing the freeboard ratio would allow the higher 
emitting higher risk facilities to achieve compliance with this 
proposed standard. The available information indicates that solvent 
switching, vapor capture, maintenance, reduced solvent use and limiting 
cleaning runs would be the primary components of any small decrease in 
costs.
    In summary, we are proposing two options that cap facility-wide 
emissions at 40,000 and 25,000 kg/yr calculated as MC-equivalents.

III. Rationale for the Proposed Rule

A. What is our approach for developing residual risk standards?

    Section 112(f)(2)(A) of the CAA states that if the MACT standards 
for a source emitting a:

    ``* * * known, probable, or possible human carcinogen do not 
reduce lifetime excess cancer risks to the individual most exposed 
to emissions from a source in the category * * * to less than 1-in-
a-million, the Administrator shall promulgate [residual risk] 
standards * * * for such source category.''

    Halogenated solvent cleaning facilities subject to the proposed 
amendments emit known, probable, and possible human carcinogens. The 
docket for today's proposed rule contains documentation of the EPA's 
determination that the risk to the individual most exposed to emissions 
from halogenated solvent cleaning is expected to exceed 1-in-a-million. 
Even if we were to quantitatively consider the uncertainty and 
variability in the exposure and modeling assumptions used to derive our 
estimate of the risk to the individual most exposed, such an analysis 
is unlikely to change any decisions that would be made based on that 
level of risk.
    Following our initial determination that the individual most 
exposed to emissions from the source category considered exceeds a 1-
in-a-million individual cancer risk, our approach to developing 
residual risk standards is based on a two-step determination of 
acceptable risk and ample margin of safety. We followed the Benzene 
NESHAP approach in making CAA section 112(f) residual risk 
determinations.\1\ Our approach for this source category is the same 
approach outlined in the National Emission Standards for the Benzene 
NESHP Final Rule, (54 FR 38044, September 14, 1989.
---------------------------------------------------------------------------

    \1\ This is confirmed by the Legislative History to CAA Section 
112(f); see, e.g., ``A Legislative History of the Clean Air Act 
Amendments of 1990,'' vol. 1, page 877 (Senate Debate on Conference 
Report) ``stating that: * * * the managers intend that the 
Administrator shall interpret this requirement [to establish 
standards reflecting an ample margin of safety] in a manner no less 
protective of the most exposed individual than the policy set forth 
in the ``Residual Risk Report to Congress, March 1999. EPA-453/R-99-
001, p. ES-11)''.
---------------------------------------------------------------------------

B. How did we estimate residual risk?

    The EPA's ``Residual Risk Report to Congress'' (EPA-453/R-99-011) 
provides the general framework for conducting risk assessments to 
support decisions made under the residual risk program. The approach 
used to assess the risks associated with our halogenated solvent 
cleaning facilities is consistent with the technical approach and 
policies described in the Residual Risk Report to Congress. Details of 
the risk assessment performed in support of this proposal are presented 
below and provided in the risk document in the rulemaking docket.
1. How did we estimate the emission and stack parameters for these 
sources?
    Three sources of data were used to characterize the source category 
for the residual risk assessment: EPA's 1999 National Emissions 
Inventory (NEI) database; a sample of MACT compliance reports obtained 
from states and EPA regions; and information compiled from Clean Air 
Act Title V permits. Together, these sources provided data for 2,672 
unique cleaning machines at 1,167 unique facilities. The 1,167 
facilities represent approximately 61 percent of the 1,900 total 
facilities estimated to be in the source category.
    The majority of the data, approximately 90 percent, were obtained 
from the 1999 NEI database, (i.e., the NEI provided data on 1,093 
facilities). The types of data obtained from the NEI database include 
machine type (from SCC codes and unit descriptions), HAP emissions 
data, and stack characteristics. The compliance reports collected for 
the residual risk assessment provided information for 195 cleaning 
machines at 96 facilities. The types of data obtained from the 
compliance report include machine types, machines sizes, solvent 
consumption rates, HAP emissions data, compliance options, and control 
equipment choices. We gathered machine-specific data for continuous web 
cleaning machines from Title V permits and other sources. These data, 
which included 74 cleaning machines at seven facilities, were added to 
the cleaning machine data obtained from compliance reports.
    Halogenated solvent cleaning machines are co-located with many and 
diverse types of industries. An analysis of MACT source category codes 
in the 1999 NEI data found that approximately 74 percent of the 1,093 
halogenated solvent cleaning sources in our database are co-located 
with at least one other source category. Approximately 80 percent of 
the halogenated solvent emissions from solvent cleaning machines 
occurred at facilities where other source categories appeared to be co-
located. However, because of the diversity of co-located source 
categories, this risk assessment evaluated the emissions coming from 
the degreasing operations only and did not consider emissions of HAPs 
that were identified

[[Page 47677]]

for co-located, non-degreasing operations.
    The residual risk assessment used HAP emissions data from the 
assessment database described above, (i.e., the 1,167 facilities). 
These data were used to estimate the baseline residual risks for the 
facilities in the category and to evaluate regulatory options developed 
to look at further HAP emission reductions. Nearly all of the data 
reflects actual emissions (details of how EPA estimated emissions are 
discussed in the Risk Assessment for Halogenated Solvent Cleaning 
Source Category {Risk Assessment Support Document{time}  located in the 
docket for this proposed rulemaking). In the few instances where we had 
the data to estimate the MACT allowable emissions and to compare those 
estimates with the emissions reported in NEI, the allowable emissions 
were, on average, a factor of 2 higher.
    Compliance with the 1994 MACT is accomplished using one of three 
compliance options. Only two of the compliance options are based on a 
numerical limit and would allow estimates of MACT allowable emissions 
to be calculated if information on machine size were available. For 
these compliance options, allowable emission rates may exceed actual 
emissions. For the control equipment compliance option which does not 
include a numerical emission limit, allowable emissions cannot be 
estimated but could be considered equivalent to actual emissions. 
Approximately 58 percent of the facilities in our assessment (i.e., 
those using the control equipment compliance option) would fall into 
this category.
    Data obtained from MACT compliance reports required processing to 
prepare emissions rates for use in the residual risk assessment. The 
types of data and level of detail in the compliance reports varied 
depending upon which of the three MACT compliance options were chosen, 
the specific report type available (e.g., initial notification report, 
annual compliance reports) available, and the report format. To use as 
much of the available information as possible, emission rate estimation 
methods were developed for various combinations of available data (see 
Appendix A in the Risk Assessment Support Document for details). These 
methods were used to estimate actual emissions rates for each cleaning 
machine. If more than one machine existed at a facility, the machine-
level emission estimates were added together to yield facility-level 
totals.
    NEI provides emission data for each HAP and emission point at a 
source and are reported in kilograms per year. For the residual risk 
assessment, NEI emission rates were used as obtained from NEI. No 
further processing of the data (e.g., to standardized units) was 
needed. However, total facility-level emissions were calculated for 
each HAP when sources had multiple degreasing emission points (i.e., 
multiple degreasing machines).
    To fully represent the national coverage of these sources, we 
scaled results from the 1,167 facilities identified in our assessment 
database to the 1,900 facilities currently estimated to be in the 
source category. When this was done, the total estimated HAP emissions 
from the source category were approximately 16,000 tons per year. These 
emissions consist of 38 percent TCA, 35 percent TCE, 15 percent PCE, 
and 12 percent MC. The total estimated carcinogenic HAP emissions (MC, 
TCE and PCE) from the source category are approximately 9,700 tons/
year.
    MC emissions in 1999 were just over 1,300 tons from about 218 
facilities, while in 2002, about 400 tons were emitted from 194 
facilities, representing about a 70 percent decrease in emissions. 
About 11 percent of facilities using MC in 1999 ceased using MC or 
ceased degreasing operations altogether.
    In 1999, TCE emissions were 3,000 tons from about 320 facilities. 
In 2002, TCE emissions had decreased 24 percent to 2,300 tons; however, 
the number of facilities using TCE increased 10 percent to 357.
    In 1999, PCE emissions were estimated at about 1,300 tons from 
about 200 facilities, however by 2002, PCE emissions had increased 
approximately 73 percent to about 2,200 tons. There was a 10 percent 
drop in the number of facilities using PCE in 2002.
    In 1999, about 3,700 tons of TCA were emitted from about 565 
facilities. In 2002, TCA emissions were about 2,300 tons from 473 
facilities, representing a 38 percent decrease in emissions and a 16 
percent decrease in facilities using TCA.
    In 1991, TCA dominated use with 62 percent of the halogenated 
solvent degreasing demand. By 1998, the demand for TCA had decreased by 
87 percent. In a critical period between 1991 and 2002, TCA was being 
phased out while remaining stock-piles at facilities with non-essential 
activities were being used until depleted. In the 2002 NEI, there were 
decreases in emissions of TCA, MC and TCE (by about 1,400 tons, 900 
tons, and 700 tons, respectively) compared to 1999 NEI). From 1999 to 
2002, emissions of PCE increased 73 percent (by about 900 tons). 
Overall emissions data for the total of all four HAP from 1999 to 2002 
indicated a 23 percent reduction in total emissions and an 8 percent 
decrease in the number of facilities.
    Therefore, although it appears that between 1999 and 2002, 
decreases in use of TCA, MC and TCE were partially offset by increases 
in PCE use. This was due to switching HAP solvents, switching to other 
non-HAP cleaning technologies, and elimination of solvent cleaning 
altogether.
2. How did we estimate the atmospheric dispersion of emitted 
pollutants?
    A nationwide, multi-facility version of EPA's Human Exposure Model, 
HEM-Screen, was used to assess chronic exposure and risk. HEM-Screen 
contains an atmospheric dispersion model with meteorological data and 
year 2000 population data at the census block level from the U.S. 
Bureau of Census. HEM-Screen includes meteorological data for 348 
stations across the U.S. The model selects the meteorological data for 
the station closest to each facility and uses this to estimate long-
term (i.e., annual average or greater) ambient concentrations of 
pollutant air emissions for nodes on a radial grid surrounding each 
facility. HEM-Screen then estimates concentrations at individual census 
block centroid locations within this grid from the modeled 
concentration results for grid nodes.
    For assessment of risk and hazard from chronic exposures, it was 
assumed that the total annual emissions derived for each facility were 
evenly distributed over the course of a year (i.e., a constant emission 
rate).
    Although the HEM-Screen model can accommodate source-specific 
release parameters, the same values were used for stack height, stack 
diameter, exit gas velocity, and exit gas temperature for all sources. 
The release parameters used for the risk assessment were derived from 
data obtained from the 1999 NEI. All emissions in the analysis were 
modeled as point source releases emitted from vertical stacks. The 1999 
NEI includes release parameters for approximately 611 (out of the 
1,093) facilities. The arithmetic mean values for each parameter were 
used in this analysis as representative values for stack height, stack 
diameter, exit gas velocity, and exit gas temperature. A maximum 
modeling radius of 20 km around each facility was used, and flat 
terrain was assumed for all facilities (e.g., no complex terrain was 
included in the modeling).

[[Page 47678]]

    No adjustments were made to the estimated ambient concentrations 
for reactivity of the HAPs being assessed. The exposures of most 
interest for this chronic assessment (i.e., exposures that occur at the 
point of maximum impact and other exposures that result in appreciable 
cancer risks) occur in the immediate vicinity of the source and within 
a short time period of release (i.e., minutes). Therefore, the impact 
of reactivity of the HAPs is relatively insignificant in the context of 
this exposure scenario.
3. How were cancer and noncancer risks estimated?
    The residual risk analysis addresses halogenated solvent cleaning 
machines subject to the 1994 MACT standards (40 CFR Part 63, subpart T) 
and estimates potential risks due to HAP emissions from sources that 
emit one or more of the regulated HAPs that are still used (i.e., MC, 
PCE, TCE and TCA). The risk assessment did not include the HAPs carbon 
tetrachloride and chloroform because their use was phased out in 1996.
    The assessment only considered the inhalation pathway as the 
primary route of exposure for humans because all of the four remaining 
HAPs are highly volatile compounds. In addition, multimedia fugacity 
modeling results indicate that the majority (over 99 percent) of each 
of these four source category HAP partitions preferentially to air 
rather than water, soil, or sediment (Risk Assessment Support 
Document). Some persistent and bioaccumulative (PB) substances can also 
pose human health risks via exposure pathways other than inhalation. 
EPA has developed a list of PB HAPs based on information developed 
under the Pollution Prevention Program, the Great Waters program, and 
the Toxics Release Inventory and additional analysis conducted by 
OAQPS. None of the four HAPs found in halogenated solvent cleaning 
machine vapors are included on this list. Consequently, exposures to 
these four HAPs via non-inhalation pathways were assumed to be minimal 
for this source category, and a quantitative risk characterization for 
multi-pathway exposures to humans was not carried out as a part of the 
residual risk assessment.
    We evaluated the potential for these HAPs to pose risks to the 
environment by conducting a screening-level ecological risk assessment 
for the baseline scenario. This assessment was intended to determine if 
HAPs emitted from these facilities pose a risk to ecological receptors 
including threatened and endangered species. The scope of the 
ecological screen was based on the fact that the HAPs emitted are all 
volatile and were shown to preferentially partition to air rather than 
soil or water, (i.e., the majority of the HAPs emitted (over 99 
percent) will remain in the atmosphere rather than deposit onto soil, 
plants, or aqueous environments. A more detailed explanation of this 
screening assessment may be found in the Residual Risk support 
document.
    The analysis estimated the potential for emissions from this source 
category to result in increased cancer risk and chronic and acute 
(i.e., one-hour) non-cancer hazard. Table 2 of this preamble outlines 
the cancer and chronic non-cancer dose-response values we used on the 
analysis.

                          Table 2.--Cancer and Chronic Non-Cancer Dose-Response Values
----------------------------------------------------------------------------------------------------------------
                                                                  Chronic reference      Cancer Unit Risk  (URE)
                                                               concentration or (RfC)    Estimate ([mu]g/m\3\)-1
                             HAP                               similar value (mg/m\3\) -------------------------
                                                             --------------------------
                                                                 Value        Source       Value        Source
----------------------------------------------------------------------------------------------------------------
Methylene Chloride..........................................          1.0        ATSDR      4.7E-07         IRIS
Perchloroethylene...........................................         0.27        ATSDR      5.9E-06      CAL and
                                                                                            7.1E-07        OPPTS
Trichloroethylene...........................................          0.6          CAL      2.0E-06          CAL
1,1,1,-Trichloroethane......................................          1.0          CAL            -           -
----------------------------------------------------------------------------------------------------------------
Notes:
Source: EPA's air toxics Web site at http://www.epa.gov/ttn/atw/toxsource/summary.html, table 1 (values for
  assessing long-term inhalation risks) dated February 28, 2005. Specific source abbreviations: IRIS = EPA's
  Integrated Risk Information System; ATSDR = Agency for Toxic Substances and Disease Registry: CAL = California
  Environmental Protection Agency; OPPTS = Office of Prevention, Pesticides and Toxic Substances. The dash (-)
  for 1,1,1,-trichloroethane indicates that there are no data available at this time to indicate that this HAP
  is a carcinogen: the current EPA weight-of-evidence for carcinogenicity for this HAP is ``D'' (not
  classifiable). This HAP was not considered in the risk analysis for carcinogenic effects.

    Estimates of maximum individual cancer risk and chronic noncancer 
hazard index (HI) were calculated for each census block around each 
source by multiplying the long-term concentrations at each block by the 
appropriate cancer URE and summing or by dividing those concentrations 
by the appropriate reference concentration (RfC) and summing, 
respectively. The total number of people exposed at various risk and 
chronic HI levels were compiled to provide a distribution of population 
risks.
    Acute (short-term) exposures to HAPs were estimated using EPA's 
SCREEN3 model. SCREEN3 is a single source Gaussian plume model which 
predicts the off-site maximum, short-term (one-hour) ambient 
concentrations of emitted HAPs at any distance from the source 
irrespective of population locations. To estimate maximum short-term 
emission rates, annual emission rates were adjusted using an assumed 
operating schedule of 8 hours/day, 260 days/year. The receptor location 
evaluated for the acute exposure analysis assumed that individuals may 
spend brief amounts of time at any location around a facility even 
though they may not reside in those locations. The maximum one-hour 
ambient concentrations were compared to acute non-cancer dose-response 
values to obtain an estimate of the potential for acute non-cancer 
hazard.
4. What factors are considered in the risk assessment?
    The risk assessment was designed to generate a series of risk 
metrics that would provide information for a regulatory decision. The 
metrics include both the maximum individual risk (MIR) and the 
population distribution of risk, the latter providing perspective on 
the potential public health impact by addressing each of the following 
questions:

[[Page 47679]]

     How many people living around the halogenated solvent 
cleaning facilities have potential risks greater than 1-in-a-million 
and other risk levels?
     What is the estimated cancer incidence in the population 
due to emissions from these facilities?
    Background exposures from other local or long-distance sources were 
not considered in the determination of incremental residual risk. To 
estimate the maximum individual risk (MIR), we assumed that people were 
continuously exposed for a lifetime of 70 years to the model-predicted 
ambient concentration at a census block around that facility. To better 
estimate the distribution of exposures and risks across the population, 
we developed an approach using a Monte Carlo simulation method (see 
Appendix F of the Risk Assessment Support Document for details) which 
accounts for variations in residency time.

C. What are the results of the baseline risk assessment?

    The baseline residual risk assessment for the halogenated solvent 
cleaning source category used HAP emissions data from an assessment 
database that included 1,167 sources. This assessment database 
represents approximately 61 percent of the 1,900 facilities in the 
source category. Estimates of maximum individual cancer risk and 
chronic non-cancer hazard as well as distributions of cancer risks and 
noncancer hazards across the exposed populations were calculated for 
each facility. Results presented in this section have been scaled-up 
proportionally to reflect results for the 1,900 facilities in the 
source category. In addition, the risk results for the population risk 
distributions are estimated to reflect varying exposure durations due 
to the variability in residency times.
    Table 3 of this preamble summarizes the estimated lifetime cancer 
risk results for the baseline level of emissions. The table shows the 
number of people in the exposed population and the number of 
halogenated solvent cleaning facilities that are associated with 
various levels of lifetime cancer risk. Depending on which cancer 
potency value is used for PCE, the highest risk to an individual living 
in the vicinity of any of the halogenated solvent cleaning facilities 
(the MIR) is between 90-in-a-million and about 200-in-a-million. For 
the exposed population within 20 kilometers to the facilities, the 
number of people with risks greater than or equal to 1-in-a-million is 
as high as 5,900,000 people (using the CalEPA URE for PCE), with 
between zero and 90 of these exposed to risks greater or equal to 100-
in-a-million. The annual cancer incidence is estimated to be between 
0.2 and 0.4 cases per year. The numbers of facilities in the source 
category which pose various levels of maximum individual lifetime 
cancer risks are presented in Table 3 of this preamble (using the 
CalEPA potency for PCE). These results show that source category 
emissions from 539 facilities (approximately 28 percent of the sources 
in the source category) were estimated to pose a maximum incremental 
increase in lifetime cancer risk at or above 1-in-a-million. Of the 539 
facilities, 124 were found to pose a maximum cancer risk greater than 
or equal to 10-in-a-million and seven of these facilities were 
estimated to pose a maximum cancer risk of 100-in-a-million or more. 
Six-hundred ninety facilities emit only the non-carcinogen TCA and, 
therefore, pose no cancer risk. The estimated numbers of facilities 
above each risk level will decrease using the OPPTS URE for PCE.

   Table 3.--Population Risk Distribution and Number of Facilities at
  Various Levels of Risk--Baseline (Scaled to National Level)\1\--Uses
                    CalEPA Cancer Potency for PCE \6\
------------------------------------------------------------------------
                                                             Number of
                                                           facilities in
                                                            the source
                                          National-scale   category with
  Estimated lifetime cancer risk (in-a-   population \2\      maximum
                million)                        \3\       estimated risk
                                                              at the
                                                             Specified
                                                             level \4\
------------------------------------------------------------------------
>=100...................................              86               7
>=10 to < 100...........................          42,000             117
>=1 to < 10.............................       5,900,000             415
<1 or no cancer risk (i.e., emit non-        200,000,000      \5\ 1,361
 carcinogen only).......................
------------------------------------------------------------------------
\1\ Represents the estimated numbers of people residing in census blocks
  with concentrations associated with risks at the designated risk
  level.
\2\ National-scale population estimated for this source category by
  multiplying the populations at the specified cancer risk level by
  1,900/1,167. Population counts have been rounded.
\3\ These population numbers are estimated to reflect residency time
  (exposure duration) variations.
\4\ Estimated by multiplying the number of sources at the specified
  cancer risk level (in Table B-1 of the Risk Assessment Support
  Document) by 1,900/1,167.
\5\ Calculated as 671 (sources at < 1 in-a-million risk) plus 690
  (sources that emit the non-carcinogen TCA only).
\6\Use of OPPTS URE for PCE will lower risk impacts.

    We also evaluated the potential for adverse health effects other 
than cancer. Calculated chronic noncancer HIs were below 1 for all 
1,167 facilities included in the risk assessment. The highest HI was 
estimated to be 0.2. Given these results, it is expected that chronic 
non-cancer HIs would be below one for all 1,900 facilities in the 
source category.
    An ecological screening assessment to assess the inhalation risk to 
potential terrestrial receptors was conducted to determine if there 
were any potentially significant ecological effects that warranted a 
more refined level of analysis. Maximum long-term air concentrations of 
HAPs at the most exposed census block centroid were used as the 
exposure concentrations, and estimated exposure concentrations were 
compared to health protective ecological toxicity screening values. 
Calculated hazard quotients associated with terrestrial ecological 
receptors were well below one for all HAPs at all facilities. Because 
of the health-protective assumptions used in this assessment, and the 
fact that these HAPs are not persistent, bioaccumulative, or likely to 
deposit on soil, plants, or water, it is believed that the ecological 
screening values developed would also be protective of ecological 
receptors that are threatened or endangered.
    We acknowledge that there are uncertainties, as well as 
conservatism in various aspects of risk assessment due to the use of 
some modeling and exposure assumptions. Specific possible

[[Page 47680]]

uncertainties in the risk assessment include: The size of the source 
category, use of actual versus allowable emissions, lack of source 
specific data on peak emissions, and modeling uncertainties (e.g., 
meteorology, emission point locations, release parameters, urban versus 
rural dispersion, population size and exposure, co-location issues, and 
dose response values). A detailed analysis of each of the possible 
sources of uncertainty in the risk analysis is contained in the Risk 
Assessment Support Document, available in the docket for this 
rulemaking.

D. What is our proposed decision on acceptable risk?

    In the 1989 Benzene NESHAP (54 FR 38044, September 14, 1989), the 
first step of the ample margin of safety framework is the determination 
of acceptability (i.e., are the estimated risks due to emissions from 
these facilities ``acceptable''). This determination is based on health 
considerations only. The determination of what represents an 
``acceptable'' risk is based on a judgment of ``what risks are 
acceptable in the world in which we live'' (54 FR 38045, September 14, 
1989), quoting the Vinyl Chloride decision, recognizing that our world 
is not risk-free.
    In the 1989 Benzene NESHAP (54 FR 38044, September 14, 1989), we 
determined that a maximum individual risk of approximately 100-in-a-
million should ordinarily be the upper end of the range of acceptable 
risks associated with an individual source of emissions. We defined the 
maximum individual risk as the estimated risk that a person living near 
a plant would have if he or she were exposed to the maximum pollutant 
concentrations for 70 years. We explained that this measure of risk is 
an estimate of the upper bound of risk based on health protective 
assumptions, such as continuous exposure for 24 hours per day for 70 
years. We acknowledge that maximum individual risk ``does not 
necessarily reflect the true risk, but displays a conservative risk 
level which is an upper bound that is unlikely to be exceeded.''
    Understanding that there are both benefits and limitations to using 
maximum individual risk as a metric for determining acceptability, the 
Agency acknowledged in the 1989 Benzene NESHAP (54 FR 38044, September 
14, 1989), that ``consideration of maximum individual risk * * * must 
take into account the strengths and weaknesses of this measure of 
risk.'' Consequently, the presumptive risk level of 100-in-a-million 
provides a benchmark for judging the acceptability of maximum 
individual risk, but does not constitute a rigid line for making that 
determination. In establishing a presumption for the acceptability of 
maximum individual risk, rather than a rigid line for acceptability, we 
explained in the Benzene NESHAP that risk levels should also be weighed 
with a series of other health measures and factors, discussed below.
    We estimate that the maximum individual lifetime cancer risk 
(discussed below) associated with the 1994 national emission standards 
for halogenated solvent cleaning is between 90 and 200-in-a-million. In 
making the decision on the acceptability of the MIR risk level seen in 
this assessment, the Benzene NESHAP explains that additional factors 
may be considered along with the MIR. These factors can include the 
number of people exposed within each individual lifetime risk range, 
associated incidence of cancer, the policy assumptions and 
uncertainties, the weight of the scientific evidence for human health 
effects and other quantified or unquantified health effects. The 
principal reasons that lead us to believe that the MIR is acceptable 
are the following: the maximum risk could be as high as 90 to 200 in-a-
million, just above the presumptive acceptable level; at least 95 
percent of the exposed population have risks below 1-in-a-million; at 
most, only about 90 people in the exposed population near only 7 of the 
1,900 facilities are estimated to be exposed at risk levels above 100 
in-a-million; and the annual incidence of cancer resulting from the 
limits in the 1994 national emission standards is between 0.2 and 0.40 
cases per year. In addition, no significant noncancer health effects or 
adverse ecological impacts are anticipated at this level of emissions.
    Therefore, we have decided that the risks associated with the 
limits in the 1994 national emission standards are acceptable.

E. What is our proposed decision on ample margin of safety?

    In the second step of the ample margin of safety framework we 
considered setting standards at a level which may be equal to or lower 
than the acceptable risk level and which protects public health with an 
ample margin of safety. In making this determination, we considered the 
estimate of health risk and other health information along with 
additional factors relating to the appropriate level of control, 
including costs and economic impacts of controls, technological 
feasibility, uncertainties, and other relevant factors.
1. What risk reduction alternatives did EPA evaluate?
    Six emission levels were developed to evaluate reductions in 
residual risk if post-MACT emissions (i.e., baseline emissions) were 
controlled further. The emission levels are not based on specific 
emission control technologies or practices. The alternatives are a 
range of maximum facility-wide emissions levels (emission limits or 
``caps''). The emission levels would apply to the total emissions from 
all of a facility's solvent cleaning machines that are subject to the 
1994 MACT standards (40 CRF Part 63, subpart T). We believe that 
solvent-switching and traditional technologies and practices, 
implemented for further post-MACT control of HAP emissions, could 
achieve these emissions levels.
    Emission levels for the proposed regulatory options were derived 
based on the risk assessment results for the baseline level. To develop 
the proposed risk-based alternatives, all emissions rates in the 
assessment database were first converted to MC-equivalents based on the 
relative cancer potency of the HAPs emitted. The cancer potency-
weighted MC-equivalent emissions rate was calculated as the estimated 
emissions for the HAP in kg/yr or lb/yr times the unit risk estimate 
(URE) for the HAP divided by the URE for MC.
    For the purpose of calculating MC-equivalent emissions as well as 
the risk impacts of the various control scenarios, we have used the 
upper end of the URE range (CalEPA) for PCE. We also describe how the 
risk impacts might change if the OPPTS URE is used. For purposes of 
implementing any control option in the final rule, we take comment on 
the use of the OPPTS URE, the CalEPA URE, or some other value in 
implementing the final rule.
    The six levels are summarized below:
     100,000 level--Sources would reduce MC-equivalent 
emissions to no more than 100,000 kg/yr (220,000 lbs/yr).
     60,000 level--Sources would reduce MC-equivalent emissions 
to no more than 60,000 kg/yr (132,000 lbs/yr).
     40,000 level--Sources would reduce MC-equivalent emissions 
to no more than 40,000 kg/yr (88,000 lbs/yr).
     25,000 level--Sources would reduce MC-equivalent emissions 
to no more than the 25,000 kg/yr (55,000 lbs/yr).
     15,000 level--Sources would reduce MC-equivalent emissions 
to no more than 15,000 kg/yr (33,000 lbs/yr).

[[Page 47681]]

     6,000 level--Sources would reduce MC-equivalent emissions 
to no more than 6,000 kg/yr (13,200 lbs/yr).
    Table 4 of this preamble shows that the decrease in MIR ranges from 
75 percent with a 100,000 kg/yr emission level (i.e., from 200-in-a-
million baseline to 50-in-a-million) to 99 percent with an emission 
level of 6,000 kg/yr (i.e., from 200-in-a-million baseline to 3-in-a-
million). The corresponding annual incidence estimates decrease over 
the range from 35 percent for the 100,000 kg/yr emission level to 90 
percent for the 6,000 kg/yr level. Likewise, there are large shifts in 
the number of people with risks greater than or equal to one-in-a-
million to below one-in-a-million. The reduction in population with 
risks greater than or equal to one-in-a-million ranges from 66 percent 
for the 100,000 kg/yr emission level to over 99 percent for the 6,000 
kg/yr level.
    Table 5 of this preamble presents the number of facilities at 
estimated cancer risk levels for the emission levels. Baseline results 
are provided for comparison. Numbers represent national-scale estimates 
(i.e., the numbers of facilities were scaled by a factor of 
approximately 1.6) and the higher-end of the cancer potency range 
(CalEPA) for PCE was used.

                                               Table 4.--Cancer Risk Results--Baseline vs. Emission Levels
                                                               [Scaled to National Level]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Baseline              Emission Levels (max MC-equivalent emissions in kg/yr)
                                                              ------------------------------------------------------------------------------------------
                     Cancer risk results                                                                Proposed     Proposed
                                                                   (no        100,000       60,000      option 1     option 2      15,000       6,000
                                                                 control)                                40,000       25,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Individual Risk (in-a-million).......................          200           50           30           20           10            8            3
Annual Incidence.............................................         0.40         0.26         0.21         0.17         0.13         0.09         0.04
Estimated Lifetime Cancer Risk (in-a-million)................                            Estimated National Population \1\ \2\
>= 1 to < 10.................................................    5,900,000    2,000,000    1,200,000      630,000      200,000      200,000        8,200
>= 10 to < 100...............................................       42,000        5,100        1,400          700           67            0            0
>= 100.......................................................           86            0            0            0            0            0            0
                                                              ------------------------------------------------------------------------------------------
Total Population at >= 1.....................................    5,942,086    2,005,100    1,201,400      630,700      200,067      200,000       8,200
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ National population estimated for this source category by multiplying the populations at the specified cancer risk level by 1,900/1,167. Population
  counts for the individual risk bins have been rounded to two significant figures.
\2\ These population numbers reflect residency time (exposure duration) variations.


                                 Table 5.--Number of Facilities at Various Levels of Risk--Baseline vs. Emission Levels
                                                               [Scaled to National Level]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Number of Facilities in the Source Category at the Estimated Risk Level \1\
                                                              ------------------------------------------------------------------------------------------
                                                                 Baseline              Emission Levels  (max MC-equivalent emissions in kg/yr)
        Estimated Lifetime Cancer Risk  (in-a-million)        ------------------------------------------------------------------------------------------
                                                                                                        Proposed     Proposed
                                                                    (no       100,000       60,000      Option 1     Option 2      15,000       6,000
                                                                control)                                 40,000       25,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
>= 100.......................................................            7            0            0            0            0            0            0
>= 10 to < 100...............................................          117           85           57           29            7            0            0
>= 1 to < 10.................................................          415          453          477          501          492          461          239
< 1 or no cancer risk (i.e., facilities emit non-carcinogen          1,361        1,362        1,366        1,369        1,402        1,439       1,660
 only) \2\...................................................
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Estimated by multiplying the number of facilities at the specified cancer risk level by 1,900/1,167.
\2\ Calculated as facilities at < 1-in-a-million risk plus 690 (facilities that emit the non-carcinogenic TCA only).

    We have not at this time estimated population risks for these 
scenarios using the lower end of the cancer potency range (OPPTS) for 
PCE. However, if we had, the following would be observed:
     Baseline MIR for the source category will drop to 90, but 
MIR values for each of the control scenarios will remain roughly the 
same--this is due to the fact that, with a toxicity-equivalent emission 
cap, MIR becomes directly proportional to MC-equivalent emissions (see 
Table 4 of this preamble).
     Baseline cancer incidence will drop by about half, as will 
that for each of the control scenarios.
     Population numbers above 1-in-a-million will drop, but we 
cannot say how much.
     The numbers of facilities affected by each control 
scenario will drop, as some PCE emitters will already fall below the 
emissions cap at baseline.
    For the two proposed options, we will calculate refined population 
and facility risk estimates using the OPPTS URE values for PCE in the 
final rule.
2. What are the costs of the proposed alternatives?
    The second step in the residual risk decision framework is the 
determination of standards with corresponding risk levels that are 
equal to or lower than the acceptable risk level and that protect 
public health with an ample margin of safety. In the ample margin 
decision, the Agency considers all of the health risk and other health 
information considered in the first step. Beyond that information, EPA 
considers additional factors relating to the appropriate level

[[Page 47682]]

of control, including costs and economic impacts of controls, 
technological feasibility, uncertainties, and any other relevant 
factors. As indicated above in Tables 4 and 5 of this preamble, we 
developed a range of emission levels and assessed their corresponding 
risk to determine the public health significance of possible further 
control. Before selecting our two proposed options, we considered the 
costs of each of the six alternative emission levels in providing 
various degrees of emission reduction. Table 6 of this preamble 
summarizes the costs, emission reductions, and the incremental costs 
for the control alternatives. When estimating the cost impacts for the 
various alternatives, the CalEPA URE for PCE was used to calculate MC-
equivalents. Use of the OPPTS value will reduce capital costs and 
solvent saving for each of the alternatives.

                                   Table 6.--Costs for Emission Level Options
----------------------------------------------------------------------------------------------------------------
                                                          Total                             Total
                                                        Annualized               Total      Annual
                                              Total    Capital and  Total HAP    Annual    Emission  Incremental
 Emission Limit Alternative MC-equivalent    Capital    Operation    Emission   Solvent    Control     Cost per
                   kg/yr                    Costs  ($      and      Reduction  (Savings)   Costs or   Ton of HAP
                                             million)  Maintenance    (tons/       ($     (Savings)    ($/ton)
                                                         Cost  ($      yr)      million)      ($
                                                         million)                          million)
----------------------------------------------------------------------------------------------------------------
1,000,000.................................       21.7         2.1       4,031      (7.4)      (5.2)     (1,292)
60,000....................................       31.5         3.0       4,903      (9.1)      (5.9)       (826)
40,000....................................       50.9        $4.9       5,911     (11.1)      (5.9)          16
25,000....................................       79.8         7.6       6,778     (12.8)      (4.9)       1,156
15,000....................................      120.7        11.5       7,674    ($14.6)      (2.8)       2,400
6,000.....................................      192.9        18.3       8,595     (16.4)        2.4       5,549
----------------------------------------------------------------------------------------------------------------

    To develop our cost estimates we identified a suite of traditional 
control alternatives that would both reduce emissions beyond the MACT 
and lower the cancer risk associated with the emissions. Two of the 
controls are retrofit controls that can be added to existing cleaning 
machines, three controls are solvent switching scenarios that reduce 
cancer risk through use of a less toxic solvent, and one control 
requires the replacement of existing equipment with a new vacuum-to-
vacuum cleaning machine.
    The development of the cost estimates for the solvent switching 
scenarios considered changes in the cost of the solvent, changes in 
solvent consumption rates, changes in energy requirements, costs for 
equipment modifications, and changes in productivity. Capital costs 
were scaled to 2004 dollars and were annualized assuming a 15-year 
equipment lifetime and a 7 percent interest rate. The solvent switching 
scenarios, their costs, and impacts are fully discussed in a separate 
memorandum titled ``Evaluation of the Feasibility, Costs, and Impacts 
of Switching from a Halogenated Solvent with a High Cancer Unit Risk 
Value to a Halogenated Solvent with a Lower Cancer Unit Risk Value'' 
(National Cost Impacts Memorandum), which is in the docket for this 
rulemaking.
    Costs for the vacuum-to-vacuum cleaning machines are based on 
vendor estimates obtained in 2005. The vacuum-to-vacuum cleaning 
machine capital costs were based on the replacement of a solvent 
cleaning machine with a solvent-air interface area of 2.5 m\2\, which 
is the average size of the solvent cleaning machines for which we have 
size data. Since vacuum-to-vacuum cleaning machines do not have a 
solvent-air interface, it was necessary to correlate the solvent-air 
interface area of the old machine to the cleaning capacity of the new 
vacuum-to-vacuum cleaning machine. The cost determination methods are 
contained in the National Cost Impacts Memorandum, located in the 
docket. Capital costs were annualized based on a 20-year equipment 
lifetime and a 7 percent interest rate. The 20-year equipment lifetime 
was determined based on information from equipment manufacturers. It 
was determined that a 97 percent reduction in emissions would result 
from switching from an existing solvent cleaning machine to a vacuum-
to-vacuum cleaning machine.
    The costs for the retrofit controls were based on vendor estimates 
obtained in 2005 (Table A-1 and Table A-2 in the National Cost Impacts 
Memorandum). The capital costs were based on equipment for a solvent 
cleaning machine with a solvent-air interface area of 2.5 m\2\, which 
is the average size of the solvent cleaning machines in the database 
for which size data are available. The annualized capital costs were 
based on a 15-year equipment lifetime and a 7 percent interest rate. A 
50 percent emission reduction is expected to result from the addition 
of a 1.0 Freeboard Ratio (FBR), Working Mode Cover (WC), and Freeboard 
Refrigeration Device (FRD) control combination. A 30 percent emission 
reduction is expected to result from the addition of a 1.5 FBR. These 
percent emission reductions were calculated using emissions reduction 
estimates and estimation procedures that were developed for the NESHAP.
    For each control alternative, the affected facilities (i.e., the 
facilities that must reduce emissions) were identified from the 
degreasing database based on whether the combined emissions of PCE, 
TCE, and MC exceeded the emission limit alternative being evaluated. If 
multiple solvents were emitted from a facility the emissions of each 
pollutant were weighted and totaled using equation 1.
    Once the necessary percent reduction was known for each facility, 
the compliance methods such as solvent switching, control equipment 
retrofits and machine replacement were applied to each unit in order to 
bring each facility into compliance with the appropriate limits. We 
recalculated the required percent reduction after the application of 
each control. For facilities with multiple units, several different 
combinations of controls across the units often had to be tried before 
a level of control that met the limits was achieved. To aid in the 
assigning of controls to specific units, a control decision matrix was 
developed to provide initial guidelines on what type of control to 
assign. This matrix is further outlined in the National Cost Impacts 
Memorandum, available in the docket. The controls that are available 
vary depending on the cleaning machine type, the solvent, and the 
percent control that is required. In cases

[[Page 47683]]

where more than one control is available, we made a rough starting 
assumption regarding the distribution of units. For example, for vapor 
cleaning units using PCE, there are two control options available when 
the required reduction is between 78 percent to 99 percent--PCE to MC 
and a vacuum cleaning machine. In this case, we initially assumed that 
approximately 25 percent of the units would choose the PCE to MC option 
and that approximately 75 percent of the units would choose the vacuum 
cleaning machine option. We assumed that more would choose the vacuum 
cleaning machine option because it is more universally applicable. The 
solvent switching option will be limited relative to the other options 
because TCE and MC will not meet the cleaning requirements for all 
cleaning applications. The costs and emission reductions for all units 
at all facilities with emissions above the control option limits were 
totaled to yield the total national costs and emission reductions.
    Table 6 of this preamble show that control costs increase and 
solvent savings increase as the emission limit is set lower. The lower 
the limit is established, the greater the number of units that must be 
controlled to achieve the limit. Emission reductions are greater when a 
lower limit is established, therefore, the solvent savings are greater. 
Total annual emission control costs range from a savings of 
approximately $6 million/year for the 40,000 kg and the 60,000 kg/year 
MC equivalent control options to a cost of $2 million/year for the 
6,000 kg/year MC-equivalent control alternative. Capital costs for the 
six control alternatives range from approximately $22 million for the 
100,000 kg/year MC-equivalent alternative to $193 million for the 6,000 
kg/year MC-equivalent alternative. Annualized capital costs range from 
$2 million/year for the 100,000 kg/year MC-equivalent control 
alternative to $18 million/year for the 6,000 kg/year MC-equivalent 
control alternative.
    Incremental costs are negative for the 100,000 kg and the 60,000 
kg/year MC-equivalent alternatives at ($1,292)/ton and ($826)/ton, 
respectively. Incremental costs for the remaining four alternatives are 
positive and range from $16/ton for the 40,000 kg/year MC-equivalent 
alternative to $5,549 ton for the 6,000 kg/year MC-equivalent 
alternative.
3. What regulatory options is EPA proposing?
    We are proposing two options that achieve an ample margin of 
safety. The co-proposed options set facility-wide emission limits that 
are specific to reducing MC, TCE, and PCE emissions from halogenated 
solvent cleaning facilities and provide an ample margin of safety. 
Option 1 limits facility-wide emissions of PCE, TCE and MC to 40,000 
kg/yr MC-equivalent. Option 2 limits facility-wide emissions of PCE, 
TCE and MC to 25,000 kg/yr MC-equivalent. Our review of the data shows 
that these limits can be achieved if facilities improve emission 
control through solvent switching (switching from a high risk solvent 
to one of lower health risks), reducing solvent use, and investigating 
traditionally available options to further reduce emissions. Increased 
diligence in controlling lids, installing freeboard chillers, 
increasing drying times, installing closed loop systems, and increasing 
the freeboard ratio would allow the higher emitting higher risk 
facilities to achieve compliance with the proposed standard. The 
available information indicates that solvent switching, vapor capture, 
maintenance, reduced solvent use, and limiting cleaning runs would be 
the primary components of any credits that would offset costs due to 
reduced solvent use.
    In selecting these two options, we first determined that adding a 
MC-equivalent based emission limit would provide an opportunity for 
additional risk reduction. We also determined that these two options 
were preferred over the 100,000 and 60,000 kg/yr options because they 
reduce the cancer incidence by over one half, they reduce the 
population exposed to cancer risks greater than one-in-a-million by 
over 5 million people, and both result in net annual cost savings to 
the industry.
    We also examined the impacts to small businesses associated with 
the alternative emissions limits. Our analysis showed that an emission 
limit of 15,000 kg/yr or lower could have an impact on a significant 
number of small businesses. To avoid adverse impacts to small 
businesses, we concluded that we would not propose an emission limit 
option of 15,000 kg/yr or lower.
    Option 1 capital costs are $51 million and total annualized cost 
savings of about $6 million. The net annualized cost per unit of 
emission reduction is a cost savings of $1,000 per ton of HAP solvent 
emissions avoided. Option 2 capital costs are nearly $80 million and 
considering solvent savings result in total annualized cost savings of 
nearly $5 million. As shown in the cost analysis summarized in Table 6 
of this preamble, the net annualized cost of per unit of emission 
reduction is a savings of $724 per ton of HAP solvent emissions 
avoided.
    In the final rule, we expect to select one of these options, with 
appropriate modifications in response to public comments. The emissions 
limit would subject the highest emitting facilities to control 
requirements that may require switching to a HAP solvent that has a 
lower URE, switching to a non-HAP solvent cleaning process, retrofit of 
freeboards, addition of vacuum-to-vacuum machines or use of emission 
control technology. A description of the two options we are proposing 
follows. When estimating the impacts for each of these options, the 
CalEPA URE for PCE was used, except where noted. Use of the OPPTS URE 
for PCE will change the estimated impacts.
4. Rationale for Option 1
    Under the authority of Section 112(f), we are co-proposing an 
emission limit of 40,000 kg/yr (88,000 lbs/yr) MC-equivalent to be 
applicable to facilities whose emission of MC, TCE and PCE exceed this 
emission cap. Under CalEPA, Option 1 would reduce total HAP emissions 
by as much as 5,800 tons/year. Thirty-two percent of those HAP 
emissions, about 1,860 tons/year would be PCE, 54 percent, about 3,130 
tons/year would be TCE and the remaining 14 percent, about 810 tons/
year would be MC.
    Under this proposed option, we estimate that approximately 90 
percent of the people living within 20 km of the halogenated solvent 
cleaning facility, about 5.4 million people of the original 6 million 
people, would no longer be exposed at risk levels higher than 1-in-a-
million, and the MIR would be reduced from the baseline of between 90 
and 200-in-a-million (depending on URE for PCE) to about 20-in-a-
million, representing an 80 to 90 percent reduction in the MIR. The 
cancer incidence would be reduced from the baseline of between 0.20 and 
0.40 cases per year (depending on URE for PCE) down between 0.08 to 
0.17 cases per year, a reduction of about 60 percent.
    We anticipate that as many as 25 percent of the halogenated solvent 
cleaning facilities will be affected by a 40,000 kg/year MC-equivalent 
emission limit. These facilities emit approximately 87 percent of the 
total MC-equivalent source category carcinogenic emissions.
    We estimate that nearly 380 halogenated solvent cleaning machines 
may become subject to this option. Facilities would reduce their 
emissions by selecting a suitable control option that might include one 
or more of the following: (1) Solvent switching from

[[Page 47684]]

PCE to MC, PCE to TCE or TCE to MC; (2) installation of vacuum to 
vacuum cleaning machines; (3) retrofitting a 1.5 freeboard ratio (FBR); 
or, (4) retrofitting of 1.5 FBR, working mode cover (WC), and freeboard 
refrigeration device (FRD) control combination. To achieve the emission 
limit of 40,000 kg/yr MC-equivalent, nearly 31 percent of the affected 
facilities may need to select vacuum to vacuum cleaning machines to 
achieve necessary emission reductions. We estimate the annualized 
capital costs plus the operation and maintenance (O&M) costs at nearly 
$4.4 million for these machines, yet with a solvent savings of nearly 
$8.9 million, the total annualized control costs would ultimately save 
the industry nearly $4.5 million for this emission control.
    Nearly thirty-eight percent of the affected facilities may select 
either of the two retrofitting options for their cleaning machines. We 
estimate the annualized capital cost plus the O&M cost at nearly $520 
thousand for retrofitting, yet with solvent savings of nearly $1.16 
million, the total annualized control costs would ultimately save the 
industry nearly $640 thousand for this emission control.
    The remaining 30 percent may select a solvent switching option, 
however, it is expected that only 6 percent of facilities may be able 
to switch from using PCE to using MC, yet, 17 percent of the facilities 
can switch from TCE to MC. We estimate the annualized capital cost plus 
O&M costs for solvent switching at nearly $320 thousand for solvent 
switching, yet with solvent savings of nearly $1.02 million, the total 
annualized control costs would ultimately save the industry nearly $700 
thousand for this emission control.
5. Rationale for Option 2
    Under the authority of Section 112(f), we are co-proposing an 
emission limit of 25,000 kg/yr (55,000 lbs/yr) MC-equivalent to be 
applicable to facilities whose emission of MC, TCE and PCE exceed this 
emission cap. Under Option 2, total HAP emissions would be reduced by 
6,700 tons/year. Thirty percent, 2,010 tons/year of the HAP emissions 
reduced would be PCE, 56 percent, 3,750 tons/year TCE and the remaining 
14 percent 940 tons/year would be MC.
    Under this proposed option, we estimate that approximately 97 
percent of the people living within 20 km of the halogenated solvent 
cleaning facility, about 5.8 million of the original 6 million people, 
would no longer be exposed at risk levels higher than 1-in-a-million, 
and the MIR would be reduced from the baseline of between 90 and 200-
in-a-million (depending on URE for PCE) to about 10-in-a-million, 
representing a 90 to 95 percent reduction in the MIR. The cancer 
incidence would be reduced from the baseline of between 0.20 and 0.40 
cases per year (depending on URE for PCE) down to between 0.06 and 0.13 
cases per year, a reduction of 70 percent.
    We anticipate that as many as 30 percent of the halogenated solvent 
cleaning facilities will be affected by a 25,000 kg/year MC-equivalent 
emission limit. These facilities emit approximately 92 percent of the 
total MC-equivalent source category carcinogenic emissions.
    We estimate that nearly 500 halogenated solvent cleaning machines 
may become subject to this option. Facilities would reduce their 
emissions by selecting a suitable control option that might include one 
or more of the following: (1) Solvent switching from PCE to MC, PCE to 
TCE or TCE to MC; (2) installation of vacuum to vacuum cleaning 
machines; (3) retrofitting a 1.5 FBR; or, (4) retrofitting of 1.5 FBR, 
WC and FRD control combination.
    To achieve the emission limit of 25,000 kg/yr MC-equivalent, nearly 
39 percent of the affected facilities may need to select vacuum to 
vacuum cleaning machines to achieve necessary emission reductions. We 
estimate the annualized capital costs plus O&M costs at nearly $7.1 
million for these machines, yet with a solvent savings of nearly $10.6 
million, the total annualized control costs would ultimately save the 
industry nearly $34.5 million for using the vacuum cleaning machines.
    Nearly 31 percent of the affected facilities may select either of 
the two retrofitting options for their cleaning machines. We estimate 
the annualized capital cost plus O&M costs at nearly $520 thousand for 
retrofitting, yet with solvent savings of nearly $960 thousand, the 
total annualized control costs would ultimately save the industry 
nearly $430 thousand for this emission control.
    The remaining 31 percent may select a solvent switching options, 
however, it is expected that only 6 percent of facilities may be able 
to switch from using PCE to using MC and 7 percent may switch from 
using PCE to TCE, yet, 17 percent of the facilities can switch from TCE 
to MC. We estimate the annualized capital cost plus O&M costs at nearly 
$320 thousand for solvent switching, yet with solvent savings of nearly 
$1.3 million, the total annualized control costs would ultimately save 
the industry nearly $980 thousand for this emission control.
6. Comparison of Option 1 and 2
    The Agency would conclude under this proposal that Option 1 would 
be the most effective in reducing risk and maximizing the cost savings 
associated with reducing emissions from these operations. This option 
would achieve an ample margin of safety by reducing MIR to 20-in-a-
million and reducing cancer incidence to between 0.08 and 0.17 cases 
per year. Proposed Option 2 would reduce MIR to 10-in-a-million and 
reduce incremental cancer incidence by between 0.02 and 0.04 cancer 
cases per year (or 1 to 2 cancer cases every 50 years) at an additional 
cost of roughly one million dollars per year and also requires higher 
capital investment of almost $29 million dollars over Option 1. Given 
the uncertainties associated with these risk estimates and the 
relatively small incremental changes in the distribution of risk under 
Option 2, we are proposing under Option 1 that it is not necessary to 
impose the additional control required by Option 2 to provide an ample 
margin of safety to protect public health. The agency seeks comment on 
whether to base the final rule on Option 1 or Option 2.

F. What is EPA proposing pursuant to CAA section 112(d)(6)?

    CAA section 112(d)(6) requires EPA to review and revise, as 
necessary (taking into account developments in practices, processes, 
and control technologies), emission standards promulgated under CAA 
section 112 no less often than 8 years. We reviewed available 
information about the industry and talked with industry representatives 
to investigate available emission control technologies and the 
potential for additional emission reductions. Based on our review, we 
believe that it is not necessary to revise the GACT standards for cold 
batch area sources in this rulemaking. We did not identify any 
additional control technologies beyond those that are already in 
widespread use within the source category (e.g., freeboard 
refrigeration devices, extended freeboards, working mode and downtime 
covers). Vacuum-to-vacuum machines, which were undemonstrated at the 
time of the development of the NESHAP, are now offered by several 
equipment vendors. The use of vacuum-to-vacuum cleaners has increased 
as the costs for them have declined. However, due to their batch 
design, relatively high cost, and typically small cleaning capacity, 
vacuum-to-vacuum cleaning machines are not appropriate for all 
applications. Therefore, our investigation did not identify any 
significant developments in practices,

[[Page 47685]]

processes, or control technologies for halogenated solvent cleaning 
since promulgation of the original standards in 1994. Under both 
options, we are proposing that these changes to the current halogenated 
solvent cleaning NESHAP also satisfy the requirements under our CAA 
section 112(d)(6) authority.

G. What is the rationale for the proposed compliance schedule?

    We are also proposing compliance dates for sources subject to the 
proposed revised standards pursuant to section 112(i) of the CAA. When 
Congress amended the CAA in 1990, it established a new, comprehensive 
set of provisions regarding compliance deadlines for sources subject to 
emissions standards and work practice requirements that EPA promulgates 
under CAA section 112. However, as discussed later in this section of 
this preamble, Congress also left in place other provisions in CAA 
section 112(f))4) that in certain respects are redundant or conflict 
with the new compliance deadline provisions. These provisions also fail 
to accommodate the new State-administered air operating permit program 
added in Title V of the amended CAA.
    For new sources, CAA section 112(i)(1) requires that after the 
effective date of ``any emission standard, limitation, or regulation 
under subsection (d), (f) or (h), no person may construct any new major 
source or reconstruct any existing major source subject to such 
emission standard, regulation or limitation unless the Administrator 
(or State with a permit program approved under Title V) determines that 
such source, if properly constructed, reconstructed and operated, will 
comply with the standard, regulation or limitation.'' CAA section 
112(a)(4) defines a ``new source'' as ``a stationary source the 
construction or reconstruction of which is commenced after the 
Administrator first proposes regulations under this section 
establishing an emission standard applicable to such sources.'' Under 
CAA sections 112(e)(10) and 112(f)(3), any CAA section 112(d)(6) 
emission standards and any residual risk emission standards shall 
become effective upon promulgation. This means generally that a new 
source that is constructed or reconstructed after this proposed rule is 
published must comply with the final standard, when promulgated, 
immediately upon the rule's effective date or upon the source's start-
up date, whichever is later.
    There are some exceptions to this general rule. First, CAA section 
112(i)(7) provides that a source for which construction or 
reconstruction is commenced after the date an emission standard is 
proposed pursuant to subsection (d) but before the date a revised 
emission standard is proposed under subsection (f) shall not be 
required to comply with the revised standard until 10 years after the 
date construction or reconstruction commenced. This provision ensures 
that new sources that are built in compliance with MACT will not be 
forced to undergo modifications to comply with a residual risk rule 
unreasonably early.
    In addition, CAA sections 112(i)(2)(A) and (B) provide that a new 
source which commences construction or reconstruction after a standard 
is proposed, and before the standard is promulgated, shall not be 
required to comply with the promulgated standard until 3 years after 
the rule's effective date, if the promulgated standard is more 
stringent than the proposed standard and the source complies with the 
proposed standard during the three-year period immediately after 
promulgation. This provision essentially treats such new sources as if 
they are existing sources in giving them a consistent amount of time to 
convert their operations to comply with the more stringent final rule 
after having already been designed and built according to the proposed 
rule.
    For existing sources, CAA section 112(i)(3)(A) provides that after 
the effective date of ``any emission standard, limitation or regulation 
promulgated under this section and applicable to a source, no person 
may operate such source in violation of such standard, limitation or 
regulation except, in the case of an existing source, the Administrator 
shall establish a compliance date or dates which shall provide for 
compliance as expeditiously as practicable, but in no event later than 
3 years after the effective date of such standard.'' This potential 
three year compliance period for existing sources under CAA section 
112(i)(3) matches the 3-year compliance period provided for new sources 
subject to CAA section 112(d), (f), or (h) standards that are 
promulgated to be more stringent than they were proposed, as provided 
in CAA sections 112(i)(1) and (2).
    As for new sources, there are exceptions to the general rule for 
existing sources under CAA section 112(i)(3), the most relevant being 
CAA section 112(i)(3)(B) allowance that EPA or a State Title V 
permitting authority may issue a permit granting a source an additional 
one year to comply with standards ``under subsection (d)'' if such 
additional period is necessary for the installation of controls. As 
explained below, EPA now believes that this reference to only 
subsection 112(d), rather than to CAA section 112 in general, was 
accidental on Congress' part and presents a conflict with the rest of 
the statutory scheme Congress enacted in 1990 to govern compliance 
deadlines under the amended CAA section 112.
    Even though, in 1990, Congress amended CAA section 112 to include 
the comprehensive provisions in subsection 112(i) regarding compliance 
deadlines, the enacted CAA also included provisions in CAA section 
112(f), leftover from the previous version of the Act, that apply 
compliance deadlines for sources subject to residual risk rules. These 
deadlines differ in some ways from the provisions of CAA section 
112(i). First, CAA section 112(f)(4) provides that no air pollutant to 
which a standard ``under this subsection applies may be emitted from 
any stationary source in violation of such standard * * *'' For new 
sources, this is a redundant provision, since the new provisions added 
by Congress in CAA sections 112(i)(1), (2), (3), and (7)--which 
explicitly reach standards established under CAA section 112(f)--
already impose this prohibition with respect to new sources and provide 
for the allowable exceptions to it. In contrast, for new sources, the 
prohibition in CAA section 112(f)(4) provides for no exception for a 
new source built shortly before a residual risk standard is proposed, 
makes no reference to the new Title V program as an implementation 
mechanism, and, where promulgated standards are more stringent than 
their proposed versions, makes no effort to align compliance deadlines 
for new sources with those that apply for existing sources. From the 
plain language of CAA section 112(i), it is clear that Congress 
intended in the 1990 amendments to comprehensively address the 
compliance deadlines for new sources subject to any standard under 
either subsections 112(d), (f), or (h), and to do so in a way that 
accommodates both the new Title V program added in 1990 and the fact 
that where circumstances justify treating a new source as if it were an 
existing source, a substantially longer compliance period than would 
otherwise apply is necessary and appropriate. It is equally clear that 
the language in CAA section 112(f)(4) fails on all these fronts for new 
sources.
    In addition, for existing sources, CAA section 112(f)(4)(A) 
provides that a residual risk standard and the prohibition against 
emitting HAP in

[[Page 47686]]

violation thereof ``shall not apply until 90 days after its effective 
date.'' However, CAA section 112(f)(4)(B) states that EPA ``may grant a 
waiver permitting such source a period up to 2 years after the 
effective date of a standard to comply with the standard if the 
Administrator finds that such period is necessary for the installation 
of controls and that steps will be taken during the period of the 
waiver to assure that the health of persons will be protected from 
imminent endangerment.'' These provisions are at odds with the rest of 
the statutory scheme governing compliance deadlines for CAA section 112 
rules in several respects. First, the 90-day compliance deadline for 
existing sources in CAA section 112(f)(4)(A) directly conflicts with 
the up-to-3-year deadline in CAA section 112(i)(3)(A) allowed for 
existing sources subject to ``any'' rule under CAA section 112. Second, 
the CAA section 112(f)(4)(A) deadline results in providing a shorter 
deadline for ordinary existing sources to comply with residual risk 
standards than would apply under CAA section 112(i)(2) to new sources 
that are built after a residual risk standard is proposed but a more 
stringent version is promulgated. Third, while both CAA section 
112(i)(1), for new sources subject to any CAA section 112(d), (f), or 
(h) standard, and CAA section 112(i)(3), for existing sources subject 
to any CAA section 112(d) standard, refer to and rely upon the new 
Title V permit program added in 1990 and explicitly provide for State 
permitting authorities to make relevant decisions regarding compliance 
and the need for any compliance extensions, CAA section 112(f)(4)(B) 
still reflects the pre-1990 statutory scheme in which only the 
Administrator is referred to as a decision-making entity, 
notwithstanding the fact that even residual risk standards under CAA 
section 112(f) are likely to be delegated to States for their 
implementation, and will be reflected in sources' Title V permits and 
need to rely upon the Title V permit process for memorializing any 
compliance extensions for those standards.
    While we appreciate the fact that CAA section 112(i)(3)(B) refers 
specifically only to standards under subsection 112(d), which some 
might argue means that subsection 112(i)(3), in general, applies only 
to existing sources subject to CAA section 112(d) standards, we believe 
that Congress inadvertently limited its scope and created a statutory 
conflict in need of our resolution. Notwithstanding the language of 
subparagraph (B), CAA section 112(i)(3)(A) by its terms applies to 
``any'' standard promulgated under CAA section 112, which includes 
those under CAA section 112(f), in allowing up to a three year 
compliance period for existing sources. Moreover, Congress clearly 
intended that the CAA section 112(i) provisions, applicable to new 
sources to govern compliance deadlines under CAA section 112(f) rules, 
notwithstanding the language of CAA section 112(f)(4). This is because 
CAA sections 112(i)(1) and (2) explicitly reaches the standards under 
CAA section 112(f). To read CAA section 112(i)(3)(B) literally as 
reaching only CAA section 112(d) standards, with CAA section 
112(f)(4)(B) reaching CAA section 112(f) standards, leaves the question 
as to whether there can be compliance extensions for CAA section 112(h) 
standards completely unaddressed by the statute, even though it may in 
fact be necessary in complying with a CAA section 112(h) work practice 
standard to install equipment or controls. A narrow reading of the 
scope of CAA section 112(i)(3) also ignores the fact that in many 
cases, including that of this proposed rule, the governing statutory 
authority will be both CAA section 112(f)(2) and CAA section 
112(d)(6)--the only reasonable way to avoid a conflict in provisions 
controlling compliance deadlines for existing sources in these 
situations is to read the more specific and comprehensive set of 
provisions, those of CAA section 112(i), as governing both aspects of 
the regulation.
    Nothing in the legislative history suggests that Congress knowingly 
intended to enact separate schemes for compliance deadlines for 
residual risk standards and all other standards adopted under CAA 
section 112. Rather, comparing the competing Senate and House Bills 
shows that each bill contained its own general and/or specific versions 
of compliance deadline provisions, and that when the bills were 
reconciled in conference the two schemes were both accidentally 
enacted, without fully modifying the various compliance deadline 
provisions in accord with the modifications otherwise made to the CAA 
section 112 amendments in conference.
    Nevertheless, we are proposing a compliance deadline of 2 years for 
existing sources of halogenated emissions from halogenated solvent 
cleaning machines. We believe this proposed compliance deadline is both 
reasonable and realistic for any affected facility that has to plan 
their control strategy, purchase and install the control device(s), and 
bring the control device online.

IV. Solicitation of Public Comments

A. Introduction and General Solicitation

    We request comments on all aspects of the proposed amendments. All 
significant comments received during the public comment period will be 
considered in the development and selection of the final rulemaking.

V. 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.'' An economic impact 
analysis was performed to estimate changes in price and output for 
affected halogenated solvent cleaning sources using the annual 
compliance costs estimated for proposed Options 1 and 2. Analysis for 
options 1 and 2 indicate an annual cost savings due to the reduction in 
solvent demand. Option 2 would result in higher cost savings of the 
options presented. For more information, refer to the economic impact 
analysis report that is in the public docket for this rule.
    Pursuant to the terms of EO 12866, this proposed rule has been 
determined to be a ``significant regulatory action'' because it raises 
novel legal and policy issues. Accordingly, EPA has submitted this 
action to OMB for review under EO 12866 and any changes made in 
response to OMB recommendations have been documented in the docket for 
this action.

B. Paperwork Reduction Act

    This action does not impose any new information collection burden. 
We are proposing no additional requirements in this action to direct 
owners and operators to generate, maintain, or disclose or provide 
information to or for a Federal agency. However, the Office of 
Management and Budget (OMB) has previously approved the information 
collection requirements contained in the existing regulations 40 CFR 
Part 63, Subpart T (1994 national emission standards for Halogenated 
Solvent Cleaning) under the provisions of the Paperwork Reduction Act, 
44 U.S.C. 3501 et seq. and has assigned OMB control number (2060-0273), 
EPA ICR number 1652.05. 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.

[[Page 47687]]

    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 part 63 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.
    For purposes of assessing the impact of the proposed action on 
small entities, small entity is 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.
    For Option 1, we estimate that 66 percent of the affected parent 
companies are small (186 out of 281) according to the SBA size 
standards. Of these small companies none of these is expected to have 
annualized compliance costs of more than 1 percent of sales.
    For Option 2, we estimate that 66 percent of the affected parent 
companies are small (186 out of 281) according to the SBA size 
standards. Of these small companies, 3 of these are expected to have 
annualized compliance costs of more than 1 percent of sales. Of these 
3, one is expected to have annualized compliance costs of more than 3 
percent of sales.
    After considering the economic impact of this proposed action on 
small entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. Neither of 
these proposed options impose a significant impact on a substantial 
number of small entities. This proposed action requests public comments 
on the residual risk and technology review. We continue to be 
interested in the potential impact of the proposed action on small 
entities and welcome comments on issues related to such impact.

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 
effect 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, CAA section 205 of the UMRA generally requires EPA to 
identify and consider a reasonable number of regulatory alternatives 
and adopts 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 of 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.
    The proposed rule contains no Federal mandates (under the 
regulatory provisions of Title II of the UMRA) for State, local, or 
tribal governments or the private sector. We have determined that the 
proposed 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 to the private sector in any one 
year. The total capital costs for this proposed rule are approximately 
$49 million for Option 2 and $31 million for Option 1 and the total 
annual costs are actually savings of approximately $3.0 and $3.6 
million. Thus, the proposed rule is not subject to the requirements of 
sections 202 and 205 of the UMRA.
    The EPA has determined that the proposed action 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 to the 
private sector in any 1 year. Thus, this proposed action is not subject 
to the requirements of sections 202 and 205 of the UMRA. In addition, 
EPA has determined that the proposed action contains no regulatory 
requirements that might significantly or uniquely affect small 
governments.

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'' are 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 proposed action does not have Federalism implications. It will 
not have substantial direct effect 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. None of the affected halogenated 
solvent cleaning facilities are owned or operated by State governments. 
Thus, Executive Order 13132 does not apply to the proposed action.
    In the spirit of Executive Order 13132, and consistent with EPA 
policy to

[[Page 47688]]

promote communications between EPA and State and local governments, EPA 
specifically solicits comment on the proposed action from State and 
local officials.

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 9, 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.'' The proposed action does not 
have tribal implications as specified in Executive Order 13175. It will 
not have substantial direct effect on tribal governments, on the 
relationship between the Federal government and Indian tribes, or on 
the distribution of power and responsibilities between the Federal 
government and Indian tribes, as specified in Executive Order 13175. 
Thus, Executive Order 13175 does not apply to this proposed action.

G. Executive Order 13045: Protection of Children From Environmental 
Health & Safety Risks

    Executive Order 13045 (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, EPA must evaluate the environmental health or safety 
effect of the planned rule on children, and explain why the planned 
regulation is preferable to other potentially effective and reasonably 
feasible alternatives considered by EPA.
    The proposed action is not subject to the Executive Order because 
it is not economically significant as defined in Executive Order 12866, 
and because EPA does not have reason to believe the environmental 
health or safety risks addressed by this action present a 
disproportionate risk to children. This conclusion is based on our 
assessment of the information on the effects on human health and 
exposures associated with halogenated solvent cleaning facilities.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    The proposed action 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. Further, 
we have concluded that this rule is not likely to have any adverse 
energy effects.

I. National Technology Transfer Advancement Act

    Under 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) directs EPA to use voluntary consensus standards (VCS) in 
its regulatory activities, unless to do so would be inconsistent with 
applicable law or otherwise impractical. The VCS are technical 
standards (e.g., materials specifications, test methods, sampling 
procedures, and business practices) that are developed or adopted VCS 
bodies. The NTTAA directs EPA to provide Congress, through OMB, 
explanations when the Agency does not use available and applicable VCS.
    The proposed action does not involve technical standards. 
Therefore, EPA is not considering the use of any voluntary consensus 
standards. The EPA welcomes comments on this aspect of the proposed 
rulemaking and, specifically, invites the public to identify 
potentially applicable VCS and to explain why such standards should be 
used in the proposed action.

List of Subjects in 40 CFR Part 63

    Environmental protection, Air pollution control, Hazardous 
substances, Reporting and recordkeeping requirements.

    Dated: August 9, 2006.
Stephen L. Johnson,
Administrator.

    For the reasons stated in the preamble, Title 40, chapter I of the 
Code of Federal Regulations is proposed to be amended as follows:

PART 63--[AMENDED]

    1. The authority citation for part 63 continues to read as follows:

    Authority: 42 U.S.C. 7401, et seq.

Subpart T--[Amended]

    2. Section 63.460 is amended by revising paragraphs (c), (d), and 
(g) and adding paragraph (i) to read as follows:


Sec.  63.460  [Amended]

* * * * *
    (c) Except as provided in paragraph (g) and (i) of this section, 
each solvent cleaning machine subject to this subpart that commenced 
construction or reconstruction after November 29, 1993 shall achieve 
compliance with the provisions of this subpart, except for Sec.  
63.471, immediately upon start-up or by December 2, 1994, whichever is 
later.
    (d) Except as provided in paragraph (g) and (i) of this section, 
each solvent cleaning machine subject to this subpart that commenced 
construction or reconstruction on or before November 29, 1993 shall 
achieve compliance with the provisions of this subpart, except for 
Sec.  63.471, no later than December 2, 1997.
* * * * *
    (g) Except as provided in paragraph (i), each continuous web 
cleaning machine subject to this subpart shall achieve compliance with 
the provisions of this subpart, except for Sec.  63.471, no later than 
December 2, 1999.
* * * * *
    (i) The compliance date for the requirements in Sec.  63.471 
depends on the date that construction or reconstruction commences.
    (1) Each facility with solvent cleaning machines that were 
constructed or reconstructed before [Date proposal is published in the 
Federal Register], shall be in compliance with the provisions of this 
subpart [2 years after date final rule is published in the Federal 
Register] or immediately upon startup, whichever is later.
    (2) Each facility with solvent cleaning machines that were 
constructed or reconstructed on or after [Date proposed rule is 
published in the Federal Register] and before [Date final rule is 
published in the Federal Register], shall be in compliance with the 
provisions of this subpart on [Date final rule is published in the 
Federal Register] or immediately upon startup, whichever is later.
    (3) Each facility with solvent cleaning machines that were 
constructed or reconstructed on or after [Date final rule is published 
in the Federal Register], shall be in compliance with the provisions of 
this subpart immediately upon startup.
* * * * *
    3. Section 63.471 is added to subpart T to read as follows:


Sec.  63.471  Facility-Wide Standards.

    (a) Each owner or operator of a solvent cleaning machine, except 
cold batch area source cleaning machines, shall comply with the 
requirements specified in paragraphs (1) and (2) of this section.
    (1) Maintain a log of solvent additions and deletions for each 
solvent cleaning machine.

[[Page 47689]]

    (2) Ensure that the total emissions for all solvent cleaning 
machines at the facility are equal to or less than the facility-wide 
12-month rolling total emission limit presented in Table 6 of this 
preamble as determined using the procedures in Sec.  63.471(b).

   Table 6.--Facility-Wide Emission Limits for Facilities With Solvent
                            Cleaning Machines
------------------------------------------------------------------------
                                  Proposed facility-  Proposed facility-
                                      wide annual         wide annual
        Solvents emitted          emission limits in  emission limits in
                                     kg--option 1        kg--option 2
------------------------------------------------------------------------
PCE only........................       \a\ 3,200 \b\       \a\ 2,000 \b\
                                            (26,700)            (16,700)
TCE only........................              10,000               6,250
MC only.........................              40,000              25,000
Multiple solvents--Calculate the              40,000              25,000
 MC-weighted emissions using
 equation 1.
------------------------------------------------------------------------
\a\ PCE emission limit calculated using CalEPA URE.
\b\ PCE emission limit calculated using OPPTS URE.


    Note: In the equation, the facility emissions of PCE and TCE are 
weighted according to their carcinogenic potency relative to that of 
MC. The value of A is either 1.5 or 12.5, depending on whether we 
use the OPPTS URE or the CalEPA URE for PCE. The value for B is 
4.25.


[GRAPHIC] [TIFF OMITTED] TP17AU06.003

Where:

WE = Weighted 12-month rolling total emissions in kg (lbs).
PCE = 12-month rolling total PCE emissions from all solvent cleaning 
machines at the facility in kg (lbs).
TCE = 12-month rolling total TCE emission from all solvent cleaning 
machines at the facility in kg (lbs).
MC = 12-month rolling total MC emissions from all solvent cleaning 
machines at the facility in kg (lbs).

    (b) Each owner or operator of solvent cleaning machines shall on 
the first operating day of every month, demonstrate compliance with the 
facility-wide emission limit on a 12-month rolling total basis using 
the procedures in paragraphs (1) through (5) of this section. (1) Each 
owner or operator of a solvent cleaning machine shall, on the first 
operating day of every month, ensure that the solvent cleaning machine 
system contains only clean liquid solvent. This includes, but is not 
limited to, fresh unused solvent, recycled solvent, and used solvent 
that has been cleaned of soils. A fill line must be indicated during 
the first month the measurements are made. The solvent level within the 
machine must be returned to the same fill-line each month, immediately 
prior to calculating monthly emissions as specified in paragraphs (2) 
and (3) of this section. The solvent cleaning machine does not have to 
be emptied and filled with fresh unused solvent prior to the 
calculations.
    (2) Each owner or operator of a solvent cleaning machine shall, on 
the first operating day of the month, using the records of all solvent 
additions and deletions for the previous month, determine solvent 
emissions (Eunit) from each solvent cleaning machine using 
equation 10:
[GRAPHIC] [TIFF OMITTED] TP17AU06.004

Where:

Eunit = the total halogenated HAP solvent emissions from the 
solvent cleaning machine during the most recent month i, (kilograms of 
solvent per month).
SAi = the total amount of halogenated HAP liquid solvent 
added to the solvent cleaning machine during the most recent month i, 
(kilograms of solvent per month).
LSRi = the total amount of halogenated HAP liquid solvent 
removed from the solvent cleaning machine during the most recent month 
i, (kilograms of solvent per month).
SSRi = the total amount of halogenated HAP solvent removed 
from the solvent cleaning machine in solid waste, obtained as described 
in paragraph (b)(3) of this section, during the most recent month i, 
(kilograms of solvent per month).

    (3) Each owner or operator of a solvent cleaning machine shall, on 
the first operating day of the month, determine SSRi using 
the method specified in paragraph (b)(3)(i) or (b)(3)(ii) of this 
section.
    (i) From tests conducted using EPA reference method 25d.
    (ii) By engineering calculations included in the compliance report.
    (4) Each owner or operator of a solvent cleaning machine shall on 
the first operating day of the month, after 12 months of emissions data 
are available, determine the 12 month rolling total emissions, 
ETunit, for the 12-month period ending with the most recent 
month using equation 11:
[GRAPHIC] [TIFF OMITTED] TP17AU06.005

Where:

ETunit = the total halogenated HAP solvent emissions over 
the preceding 12 months, (kilograms of solvent emissions per 12-month 
period).
Eunit = halogenated HAP solvent emissions for each month (j) 
for the most recent 12 months (kilograms of solvent per month).

    (5) Each owner or operator of a solvent cleaning machine shall on 
the first operating day of the month, after 12 months of emissions data 
are available, determine the 12-month rolling total emissions, 
ETfacility, for the 12-month period ending with the most 
recent month using equation 12:
[GRAPHIC] [TIFF OMITTED] TP17AU06.006

Where:

ETfacility = the total halogenated HAP solvent emissions 
over the preceding 12 months for all cleaning machines at the facility, 
(kilograms of solvent emissions per 12-month period).
ETunit = the total halogenated HAP solvent emissions over 
the preceding 12 months for each unit j, where i equals the total 
number of units at the facility (kilograms of

[[Page 47690]]

solvent emissions per 12-month period).

    (c) If the facility-wide emission limit is not met, an exceedance 
has occurred. All exceedances shall be reported as required in Sec.  
63.468(h).
    (d) Each owner or operator of a solvent cleaning machine shall 
maintain records specified in paragraphs (d)(1) through (3) of this 
section either in electronic or written form for a period of 5 years.
    (1) The dates and amounts of solvent that are added to the solvent 
cleaning machine.
    (2) The solvent composition of wastes removed from cleaning 
machines as determined using the procedure described in paragraph 
(b)(3) of this section.
    (3) Calculation sheets showing how monthly emissions and the 12-
month rolling total emissions from the solvent cleaning machine were 
determined, and the results of all calculations.
    (e) Each owner or operator of a solvent cleaning machine shall 
submit an initial notification report to the Administrator no later 
than [DATE]. This report shall include the information specified in 
paragraphs (e)(1) through (5).
    (1) The name and address of the owner or operator.
    (2) The address (i.e., physical location) of the solvent cleaning 
machine(s).
    (3) A brief description of each solvent cleaning machine including 
machine type (batch vapor, batch cold, vapor in-line or cold in-line), 
solvent/air interface area, and existing controls.
    (4) The date of installation for each solvent cleaning machine.
    (5) An estimate of annual halogenated HAP solvent consumption for 
each solvent cleaning machine.
    (f) Each owner or operator of a solvent cleaning machine shall 
submit to the Administrator an initial statement of compliance on or 
before [Date]. The statement shall include the information specified in 
paragraphs (f)(1) through (f)(3) of this section.
    (1) The name and address of the solvent cleaning machine owner or 
operator.
    (2) The address of the solvent cleaning machine(s).
    (3) The results of the first 12-month rolling total emissions 
calculation.
    (g) Each owner or operator of a solvent cleaning machine shall 
submit a solvent emission report every year. This solvent emission 
report shall contain the requirements specified in paragraphs (g)(1) 
through (g)(3) of this section.
    (1) The average monthly solvent consumption for the solvent 
cleaning machine in kilograms per month.
    (2) The 12-month rolling total solvent emission estimates 
calculated each month using the method as described in paragraph (b) of 
this section.
    (3) This report can be combined with the annual report required in 
Sec.  63.468 (f) and (g) into a single report for each facility.

[FR Doc. 06-6927 Filed 8-16-06; 8:45 am]
BILLING CODE 6560-50-P