47670 Federal Register / Vol. 71, No. 159 / Thursday, August 17, 2006 / Proposed Rules 

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. 

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: a-and-r-docket@epa.gov. 

• 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: 

dail.lynn@epa.gov. 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: 

pagano.dennis@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Regulated Entities. The categories and 

entities potentially regulated by the 

proposed rule include: 


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Category NAICS1 code Examples of potentially regulated entities 

Industry ................................ Any of numerous industries using halogenated solvent 

cleaning, primary affected industries 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.).

Operations at sources that are engaged in solvent 

cleaning using MC, PCE, or TCE. 

Federal, State, local, and 

tribal government.

.......................................................................................... Operations at 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: 

apple.dorothy@epa.gov , 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 technologybased 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 


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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 


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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 customdesigned 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 semienclosed 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 equallysized batch vapor cleaner. However, inline 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/m3, 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 × 10¥7 (μg/m3)¥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 (longterm) 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.’’


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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/m3. 

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 × 10¥6 (ug/m3)¥1, as well as a URE 

value developed by the EPA’s Office of 

Prevention, Pesticides and Toxic 

Substances (OPPTS) of 7.1 × 10¥7 (ug/ 

m3)¥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 onehour California Reference Exposure 

Level (a REL value of 240 mg/m3) 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/m3. CalEPA estimates that no 

adverse noncancer effects are likely in 

human populations chronically exposed 

at or below 0.6 mg/m3. 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 × 10¥6 (ug/m3)¥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/m3. 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 inline 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 


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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 facilitywide 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

Solvents emitted 

Proposed facilitywide annual emission limits in kg— 

option 1 

Proposed facilitywide annual emission limits in kg— 

option 2 

PCE only .................................................................................................................................................. a 3,200 b (26,700) a 2,000 b (16,700) 

TCE only .................................................................................................................................................. 10,000 6,250 

MC only .................................................................................................................................................... 40,000 25,000 

Multiple solvents—Calculate the MC-weighted emissions using equation 1 .......................................... 40,000 25,000 

aPCE emission limit calculated using CalEPA URE. 

bPCE emission limit calculated using OPPTS URE. 

Equation 1: 

(kgs of PCE emissions × A) + (kgs of 

TCE emissions × 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 MCequivalency 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 


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1This 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)’’. 

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. 

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 


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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} 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, HEMScreen, 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). 


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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) noncancer hazard. Table 2 of this preamble 

outlines the cancer and chronic noncancer dose-response values we used on 

the analysis. 

TABLE 2.—CANCER AND CHRONIC NON-CANCER DOSE-RESPONSE VALUES

HAP 

Chronic reference 

concentration or (RfC) 

similar value 

(mg/m3) 

Cancer Unit Risk 

(URE) 

Estimate 

(μg/m3)¥1

Value Source Value Source 

Methylene Chloride .......................................................................................................... 1.0 ATSDR 4.7E–07 IRIS 

Perchloroethylene ............................................................................................................ 0.27 ATSDR 5.9E–06 

7.1E–07 

CAL and 

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 (onehour) 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: 


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• How many people living around the 

halogenated solvent cleaning facilities 

have potential risks greater than 1-in-amillion 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 noncancer 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-amillion 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

Estimated lifetime cancer risk 

(in-a-million) 

National-scale 

population 2 3

Number of facilities in the 

source category with 

maximum 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-carcinogen only) ............................................................................................. 200,000,000 5 1,361 

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. 3These population numbers are estimated to reflect residency time (exposure duration) variations. 

4Estimated 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). 

6Use 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 noncancer 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 healthprotective 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 


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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-amillion 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-amillion; 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-amillion; 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 solventswitching 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 potencyweighted 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 MCequivalent 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). 


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• 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 onein-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] 

Cancer risk results 

Baseline Emission Levels (max MC-equivalent emissions in kg/yr) 

(no control) 100,000 60,000 

Proposed 

option 1 

40,000 

Proposed 

option 2 

25,000 

15,000 6,000 

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. 2These 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] 

Estimated Lifetime Cancer Risk 

(in-a-million) 

Number of Facilities in the Source Category at the Estimated Risk Level 1

Baseline Emission Levels 

(max MC-equivalent emissions in kg/yr) 

(no control) 100,000 60,000 

Proposed 

Option 1 

40,000 

Proposed 

Option 2 

25,000 

15,000 6,000 

≥ 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 only) 2 .......................... 1,361 1,362 1,366 1,369 1,402 1,439 1,660 

Notes: 

1Estimated 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-amillion 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 


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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

Emission Limit Alternative MC-equivalent kg/yr 

Total 

Capital 

Costs 

($ million) 

Total 

Annualized 

Capital 

and Operation and 

Maintenance 

Cost 

($ million) 

Total 

HAP 

Emission 

Reduction 

(tons/yr) 

Total Annual Solvent 

(Savings) 

($ million) 

Total Annual 

Emission 

Control 

Costs or 

(Savings) 

($ million) 

Incremental 

Cost per 

Ton of 

HAP 

($/ton) 

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-tovacuum 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 m2, which is the average size 

of the solvent cleaning machines for 

which we have size data. Since vacuumto-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-tovacuum 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 m2, 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 


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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 MCequivalent 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 MCequivalent 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 MCequivalent 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 MCequivalent. 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-tovacuum 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) MCequivalent 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-ina-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 


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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 MCequivalent, 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) MCequivalent 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-ina-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 vacuumto-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, 


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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 threeyear 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 


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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. 


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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-forprofit 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 


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47688 Federal Register / Vol. 71, No. 159 / Thursday, August 17, 2006 / Proposed Rules 

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: 

§ 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 

§ 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 

§ 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 § 63.471, no 

later than December 2, 1999. 

* * * * * 

(i) The compliance date for the 

requirements in § 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: 

§ 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. 


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(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 § 63.471(b). 

TABLE 6.—FACILITY-WIDE EMISSION LIMITS FOR FACILITIES WITH SOLVENT CLEANING MACHINES

Solvents emitted 

Proposed facilitywide annual emission limits in kg—

option 1 

Proposed facilitywide annual emission limits in kg—

option 2 

PCE only .................................................................................................................................................. a 3,200 b (26,700) a 2,000 b (16,700) 

TCE only .................................................................................................................................................. 10,000 6,250 

MC only .................................................................................................................................................... 40,000 25,000 

Multiple solvents—Calculate the MC-weighted emissions using equation 1. 40,000 25,000 

aPCE emission limit calculated using CalEPA URE. 

bPCE 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. 

WE PCE TCE B MC = × ( ) A 9 + × ( ) + ( ) ()

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: 

E SA LSR SSR unit i i i =− − ( ) 10

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: 

ET E unit unit

j

= 



 



 ( ) =

∑1

12

11

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: 

ET ET facility unit

j

i

= 



 



 ( ) =

∑1

12

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 


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47690 Federal Register / Vol. 71, No. 159 / Thursday, August 17, 2006 / Proposed Rules 

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 § 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 inline 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 § 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 


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