United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park, NC 27711
EPA 450/3-91 -020b
September 1993
Air
Dry Cleaning Facilities -    Final
Background  Information    EIS
for Promulgated Standards

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                             CONTENTS
Section

  LIST OF TABLES,
  1.0
  2.0
SUMMARY	
1.1  SUMMARY OF CHANGES SINCE'PROPOSAL  '.''-'
1.2  SUMMARY OF IMPACTS OF PROMULGATED  ACTION.
     1.2.1     Alternatives to Promulgated
               Action,
               Environmental Impacts of Promulgated
               Action.  ....  	
               Energy and Economic Impacts of
               Promulgated Action. ......
SUMMARY OF PUBLIC COMMENTS ....
            1.2.2
            1.2.3'
       2.1
       2.2
       2.3
      2.4
      2.5
      2.6
      2.7
      SELECTION OF POLLUTANTS	
      SELECTION OF AFFECTED FACILITY  .
      2.2.1    Collocation .......
      2.2.2    Applicability Criteria.
      2.2.3    Exempting Coin-Operated
               Facilities	
      EMISSION CONTROL TECHNOLOGY.
             2,
             2,
          1
          2
             2,
             2.
             2.
          3
          4
          5
             2.3.6
         Refrigerated Condensers	
         Additional  Requirements for Hamper
         Enclosures  and Room Enclosures.  .  .
         Transfer Machine  System Emissions
         Fugitive Emissions	
         Occupational Safety and Health
         Administration Permissible
         Exposure Limit. ., .  .  .  .  .,
         Diversitron Solvation®  System .  .*  !
MODIFICATION AND RECONSTRUCTION.  .  .
ECONOMIC IMPACTS 	
2.5.1    Public Health 	  ......
2.5.2    Control Costs .	]
2.5.3    Economic Considerations  .  .
ENVIRONMENTAL IMPACTS.. ., .. .  ..,
SELECTION OF MAXIMUM ACHIEVABLE CONTROL*
TECHNOLOGY AND GENERALLY AVAILABLE
CONTROL TECHNOLOGY 	
                                       Page

                                       iv

                                       1-1
                                       1-1
                                       1-4

                                       1-4

                                       1-4

                                       1-5
                                       2-1
                                       2-10
                                       2-12
                                       2-12
                                       2-14

                                       2-15
                                       2-16
                                       2-16

                                       2-18
                                       2-19
                                       2-19
                                                     2-20
                                                     2-20
                                                     2-24
                                                     2-27
                                                     2-27
                                                     2-27
                                                     2-28
                                                     2-29
            2,
            2,

            2.
            2.
            2.
        7,
        7,

        7,
        7.
        7,
    1
    2

    3
    4
    5
Regulatory Considerations	
Determining Threshold of Threat
of Adverse Effects	
Indoor Air Pollution	
Small Consumption Facilities.  .
Banning of Transfer Machine
Systems . .=.. ... ..... ., . .... .
.  2-31
.  2-31

.  2-37
.  2-38
.  2-41

,. 2-43.

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                         CONTENTS  (CONCLUDED)
  Section
              2.14 .2
              2.14.3
as a volatile Organic'compound!    ?
Carcinogen Risk Assessment
Classification of
Perchloroethylene .
Public Health Impact. * •-••-•  •  •




2. .8
2.9
2.10




2.11
2.12




2..13:
2.14

2.7.6 Reclaimers .
2.7.7 Room Enclosures . .
2.7.8 Hamper and Room Enclosures
* • / . 9 Additional Controls for
Dry-to-Dry Machines . . .
SlON^O^MI^s- '
EMISSIONS LIMITS AND PERFORMANCE TEST]

2.10.1 Operator Training Course
2.10.2 Enf orceability .
l'\l'l Sa?°n Adsorbe* Requirements
2.10.4 Refrigerated Condenser
Requirements. . .
2.10.5 Purchase Orders
2.10.6 Saturated Lint and Cartridge*
2.10.7 Compliance Timetable. .
TEST METHODS AND MONITORING. . * "
WORDING OF THE REGULATION *
2.12.1 References to Other Subparts
2.12.2 Clarifications. . uoparrs-
2.12.3 English Units . * '
2.12.4 Definitions . 	
2.12.5 Applicability ...
2.12.6 Standards . * "
EQUIVALENCY. * " 	 " *'
MISCELLANEOUS. . 	
2.14.1 Classification nf n«».<,ui 	 ^-

	 2-49
	 2-49
	 2-51

...... 2-57
	 2-62
CNG . . . 2-67
CCE
- - . . 2-71
.... 2-71
.... 2-73
• ... 2-76

«... 2-80
-... 2-83
«... 2-85
.... 2-11

• • • . 2-87
..... 2-88
• 	 2-89
• • • .. .. 2-90-
.... 2-90
«... 2-97
2-97
2-98
2-101
gep.007
                               iii

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                             LIST OF TABLES

                                                               2-2
gep.007
                                XV.

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                           1.0  SUMMARY

      On December 9,  1991,  the Environmental Protection Agency
 (EPA)  proposed national emission standards for hazardous air
 pollutants for perchloroethylene (PCE)  emissions from dry
 cleaning facilities  (56 FR 64382)  under authority of section 112
 of  the Clean Air Act.   Public comments  were requested on the  '
 proposal in the Federal Register.   There were 34 commenters
 composed mainly of States,  environmental groups,  industry trade
 associations,  and dry  cleaning equipment vendors.
      Public comments were  also requested in a notice of
 availability of new  information on control of PCE emissions
 during clothing transfer at dry cleaning facilities  that use
 transfer dry cleaning  machines.  This notice was published, on
 October 1,  1992 (57  FR 45363).   Eight comment letters were
 received.
     All of the comments that were submitted,  along  with
 responses  to these comments, are summarized in this  document.
 The summary of  comments  and responses serves as the  basis  for the
 revisions  made  to  the  standards between  proposal and
 promulgation.
 1.1  SUMMARY OF CHANGES  SINCE PROPOSAL
     Since  proposal, several important changes  have  been made to
 the regulation.  The changes affect new  and  existing dry cleaning
 machines located at major and area sources.  At proposal,  owners
 or operators,of new; dry-to-dry machines  located;at major or area
 sources were given a choice of installing carbon adsorbers  or
 refrigerated condensers as process vent control.  At
promulgation, all new dry cleaning machines located  at major or
area sources are required to install refrigerated condensers.
     The owner or operator of a new dry-to-dry machine located at
a major source is also required to install a carbon adsorber to
                               l-l

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 control the PCE emissions remaining in the dry cleaning machine
 drum at the end of the dry cleaning cycle.
      At proposal,  new transfer machine systems were allowed and
 control requirements for these systems were specified.   At
 promulgation,  new transfer machine systems are prohibited, through
 a regulatory requirement prohibiting PCE emissions from clothing
 transfer between the washer and the dryer.  This requirement
 cannot be met by new transfer machine systems even if these
 systems are enclosed in room enclosures.
      At proposal,  existing uncontrolled dry-to-dry machines
 located at major or area sources were given a choice of
 installing carbon adsorbers or refrigerated condensers  as  process
 vent control.   Existing uncontrolled transfer machine systems
 located at area sources were required to  install carbon
 adsorbers.   At promulgation,  existing uncontrolled dry-to-dry
 machines and transfer machine systems are required to install
 refrigerated condensers.   Existing controlled machines  that
 already have a carbon adsorber,  however,  are not required  to
 install a refrigerated condenser for process vent control.
     At proposal,  existing uncontrolled transfer machine systems
 located at  major  sources  were required to install carbon
 adsorbers.   At promulgation,  existing uncontrolled transfer
 machine systems located at major sources  are required to install
 refrigerated condensers as process vent control.   Existing
 controlled transfer machine^ systems  at- major sources  that  already
 have a  carbon  adsorber, however,  are  not  required to  install a
 refrigerated condenser  for process vent control.   For control of
 fugitive  emissions, all existing transfer machine  systems  located
 at major  sources,must be enclosed within a; room  enclosure  that
 exhausts  to- a  carbon adsorber.
     At proposal, the low  solvent consumption exemption for
process vent control at area sources was 220 gallons of PCE per
year for a dry-to-dry machine and 300 gallons of PCE per year for
a transfer machine system.  At promulgation, the low solvent
consumption exemption for process vent control has been lowered
and now applies to the total, PCE, solvent consumption of; all

                               1-2:

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  machines at the dry cleaning facility rather than on a per
  machine basis.  At promulgation, the low solvent consumption
  exemption for process vent control is 140 gallons of PCE per year
  for a dry cleaning facility with only dry-to-dry machines or both
  dry-to-dry machines and transfer machine systems, and 200 gallons
  of PCE per year for a dry cleaning facility with only transfer
  machines systems.
       The level of  PCE consumption distinguishing major from area
  sources is the same as at proposal;  however,  this now applies to
  the total PCE  consumption of  all machines  at  the facility rather
  than on a per  machine basis.  The level  of PCE  consumption
  distinguishing a major source from an area source is
  2,100  gallons  of PCE  per  year for a  source with only dry-to-dry
  machines,  and  1,800 gallons of PCE per year for a source with
  only transfer  machine  systems or both dry-to-dry machines  and
  transfer machine systems.
      At proposal, pollution prevention practices  (such as  leak
 detection and repair) were required only for those dry cleaning
 machines above the low solvent consumption exemption for process
 vent control.  At promulgation,  all PCE dry cleaning facilities
 must implement pollution prevention practices and operate their
 dry cleaning equipment according to the manufacturer's
 specifications.
      There were no  monitoring  requirements  included at proposal
 The> promulgated standards  now  require periodic monitoring of
 process vent control equipment.   When operating  a refrigerated
 condenser on a  dry-to-dry  machine,  a  transfer  machine  system
 dryer,  or a reclaimer,  the temperature on the  outlet side  of the
 refngerated condenser must be measured and recorded, once per
 weak.....  When  operating- a refrigerated  condenser on; a, transfer
 machine system  washer, the difference between the inlet and
 outlet  temperatures of the exhaust from the washer as it passes
 through the refrigerated condenser must be measured and recorded
 once per week.
     When operating an existing carbon adsorber to control
process vent emissions, a colorimetric indicator tube must be

                               1-3

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 used to measure and record the PCE level in the carbon adsorber
 exhaust once per week.  Periodic desorption for carbon adsorbers
 is no longer specifically required.  Instead, the owner or
 operator must follow the manufacturer's specifications for the
 proper operation of a carbon adsorber.
 1.2  SUMMARY OF IMPACTS OF PROMULGATED ACTION
 1-2.1  Alternatives to Promulgation Action^
      The regulatory alternatives are discussed in chapter 6.0 of
 the background information document (BID)  for the proposed
 standards (EPA 450/3-91-020a).  Included with these regulatory
 alternatives are estimates of the level of emission control which
 would be achieved if that alternative were selected as the basis
 for standards.
      At proposal,  the estimated reduction in PCE emissions
 achieved using a carbon adsorber was assumed to be equal to or
 greater than that achieved by refrigerated condensers based on
 measurements under optimal testing situations.   Subsequent to
 proposal,  information on solvent mileage became available from
 the results  of  a survey conducted by the California Air Resources
 Board.   This information (which included data from over 2,000 dry
 cleaning facilities)  clearly indicates  that the performance of
 carbon  adsorbers in actual practice achieves lower emission
 reduction  than  refrigerated condensers.
      The estimates  of  control efficiency associated with
 refrigerated condensers, however, have  not  changed since proposal
 and are  included in the  proposal  BID.   As discussed above,  the
 promulgated  regulation requires the use of  refrigerated
 condensers and,  as  a result,  the  estimates  of the  levels  of
 emission, control achieved  by the  promulgated standards remain:
.essentially  the  same as  that  associated with the proposed
 standards.
 1-2-2  Environmental Impacts  of Promulgated Action
     The environmental impacts are discussed in chapter 7.0 of
 the BID of the proposed  standards.  The emission reduction
 expected to  occur as a result of the control devices required by
 the promulgated standards is  6, 600 megagrams per year (Mg/yr)

                               1-4

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 [7,300 tons per year  (tpy)], an increase of 1,200 Mg/yr
 (1,300 tpy) compared to proposal due to lowering the low solvent
 consumption exemption for process vent control.  The emission
 reduction expected to occur as a result of leak detection and
 repair required by the promulgated standards is 25,800 Mg/yr
 (28,400 tpy).
      Because all existing, uncontrolled dry cleaning machines are
 required to install refrigerated condensers instead of carbon
 adsorbers under the final standards, there will be a reduction in
 water pollution and solid waste impacts from those impacts
 projected at proposal.  Note that the impacts for new dry
 cleaning machines do not change between proposal and promulgation
 because these impacts were based at proposal on the assumption
 that all new machines would be dry-to-dry machines controlled by
 refrigerated condensers.
      Carbon adsorbers produce more wastewater and solid waste
 than refrigerated condensers  due to their use of steam for
 desorption and periodic  replacement of the carbon bed.   The
 additional water pollution impacts expected to occur as. a result
 of the promulgated standards  are 0.2 Mg/yr (0.2 tpy),  a decrease
 of O.l Mg/yr (0.1 tpy) compared to proposal.   The additional
 solid waste impacts expected  to occur as  a result of the
 promulgated standards  are  2 Mg/yr  (2  tpy),  a decrease of 2  Mg/yr
 (2 tpy) compared to proposal.
      With  the  changes  noted in  this  section, the  analysis of
 environmental  impact in the proposal BID now becomes the Final
 Environmental  Impact Statement  for the promulgated standards.
 1>2*3   Energy  and  Economic Impacts of Promulgated Action
      The energy  impacts are,discussed, in chapter 7.0  of the
 Background Information Document of the proposed standards.  The
 additional energy  requirements expected to occur as a result of
 operating the  control devices to meet the promulgated standards
are 430,700 British thermal units per year  (Btu/yr)  [3 gigawatts
per year (GW/yr)], an increase of 72,000 Btu/yr (l Gw/yr)
compared to proposal.  This increase is due to lowering the low
solvent, consumption exemption for process vent control.

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      The economic impacts are discussed in the proposal document
 "Economic Impact of Regulatory Controls in the Dry Cleaning
 Industry."  The economic impact assessment includes a market
 component and a financial component.  The market component
 focuses on the adjustment of market prices and quantity of dry
 cleaning as a result of complying with the standards.  The
 financial component focuses on the ability of firms to obtain the
 money to buy the control equipment.
      The upward market price adjustment due to the promulgated
 standards is projected to range between 0.25 and 2.5 percent in
 various markets,  with the largest increases being found in small
 rural markets.   The downward adjustment in total dry cleaning is
 projected to be about 0.5 percent,  an increase of 0.3 percent
 since proposal.   If the whole quantity adjustment were translated
 into closures rather than reduction in output at many cleaners,
 the  net closures  would be projected to be  just under 300,  an
 increase of  about 270 since  proposal.   This  increase is due to
 lowering the low  solvent consumption exemption for process vent
 control.
      The financial analysis  indicates  that firms  in  below-average
 financial condition may face difficulty in obtaining the required
 funds to purchase control equipment  from traditional  loan  sources
 such as  banks.  The analysis of the  promulgated standards
 projects between 0 and  1,300 firms will be in this category.
 These firms will either obtain other financing  (vendor-aided,
 relatives, personal assets,  etc.), close, or sell their firm!
 The analysis of the proposed standards projected between 0 and
 670 firms would be in this category.  The increase is due to
 lowering the low solvent consumption exemption for process vent
control.

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                 2.0  SUMMARY OF PUBLIC COMMENTS

     A total of 42 letters commenting on the proposed standards,
the notice of availability of new information, and the background
information document  (BID) for the proposed standards were
received.  Because no one requested a public hearing on the
proposed standards, no public hearing was held.  A list of
commenters, their affiliations, and the EPA docket number
assigned to their correspondence is given in Table 2-1.
     For the purpose of orderly presentation, the comments have
been categorized under the following topics:
          Selection of Pollutants;
 1,
 2.
 3.
 4.
 5.
 6.
 7.
 8.
 9.
10.
          Selection of Affected Facility;
          Emission Control Technology;
          Modification and Reconstruction;
          Economic Impacts;
          Environmental Impacts;
          Selection of MACT and GACT;
          Selection of Format for Standards;
          Emission Limits and Performance Testing;
          Selection of Equipment and Work Practice
          Specifications;
     11.   Test Methods  and Monitoring;-
     12.   Wording of  the Regulation;
     13.   Equivalency;  and
     14.   Miscellaneous.
                              2-1

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        TABLE 2-1.
LIST OF COMMENTERS ON PROPOSED NATIONAL
 EMISSION STANDARDS FOR HAZARDOUS AIR
  POLLUTANTS FOR  SOURCE  CATEGORIES:
   PERCHLOROETHYLENE EMISSIONS FROM
        DRY CLEANING FACILITIES
 Docket item number*
                                Commenter and affiliation
 D-l
 D-2
 D-3
D-4
D-5
D-6
     Mr.  John D'Aloia,  Jr.
     Senior Associate
     Deuel & Associates,  Incorporated
     Environmental Science  and Engineering
     311  West Alma Street
     St.  Marys,  Kansas   66536

     Mr.  Jeff Johnson
     Equipment Sales  Manager
     PROS
     420  North 5th Street
     Suite 480
     Minneapolis,  Minnesota  55401

     Mr.  Michaeij. R. Lake
     Chief,  Engineering Division
     Air  Pollution Control  District
     County of San Diego
     9150  Chesapeake  Drive
     San  Diego, California  92123-1096

    Mr. Kenneth W. Holt
     Special Programs Group
    Department of Health and Human Services
    Centers for Disease Control
    Atlanta, Georgia  30333

    Ms. Lorna S. McBarnette
    Executive Deputy Commissioner
    New York State Department of Health
    Corning Tower
    The Governor Nelson A.  Rockefeller
      Empire State Plaza
    Albany, New?York: 12237

    Mr.,, Peter D... Venturini, Chief
    Stationary Source Division
    State of California
    Air Resources Board
    1102  Q Street
    Sacramento,  California   95812
                               2-2

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        TABLE 2-1.
 Docket item number3
LIST OF COMMENTERS ON PROPOSED NATIONAL
 EMISSION STANDARDS FOR HAZARDOUS AIR
  POLLUTANTS  FOR  SOURCE  CATEGORIES:
   PERCHLOROETHYLENE EMISSIONS FROM
        DRY CLEANING FACILITIES
              (CONTINUED)
              =====       	
            Commenter and affiliation
 D-7
 D-8
 D-9
D-10
D-ll
D-12
     Mr.  Michael R.  Lake '
     Chief,  Engineering Division
     Air  Pollution Control District
     County  of San Diego
     9150 Chesapeake Drive
     San  Diego,  California  92123-1096

     Mr.  Kenneth Eng,  Chief.
     Air  Compliance  Branch
     U. S. Environmental Protection Agency
     Region  II                     '      J
     Jacob K.  Javitz Federal Building
     26 Federal  Plaza
     New  York, New York   10278

     Mr.  Jack  Lauber
     New  York  State  Department of
      Environmental Conservation
     50 Wolf Road
     Albany, New York  12233-3254

     Mr. R. Darryl Banks
     Deputy Commissioner
     New York State  Department of
      Environmental Conservation
     50 Wolf Road
    Albany,  New York  12233-3254

    Ms. Helen G. Goldberger
    Ms. E.  Gail Suchman
    Assistant Attorneys General
    State of New York
    Department of Law
    120 Broadway
    New York,  New York  10271

    Mr. Robert G.  Smith
    President
    Kleen-Rite
    4444  Gustine Avenue
    St. Louis, Missouri  63116
                               2-3

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        TABLE 2-1.
LIST OF COMMENTERS ON PROPOSED NATIONAL
 EMISSION STANDARDS FOR HAZARDOUS AIR
  POLLUTANTS  FOR SOURCE  CATEGORIES:
   PERCHLOROETHYLENE EMISSIONS FROM
        DRY CLEANING FACILITIES
              (CONTINUED)
 Docket item number3
                                Commenter and affiliation
 D-13
 D-14
 D-15
D-16
D-17
D-18
     Mr.  Frank C.  Torres
     Keller and Heckman
     1001 G Street,  N.W.
     Suite 500 West
     Washington, D.C.    20001

     Mr.  Timothy A.  Vanderver,  Jr.  et al
     Patton,  Boggs,  &  Blow
     2550 M Street,  N.W.
     Washington, D.C.   20037-1350

     Mr.  Samuel A. Bleicher
     Miles &  Stockbridge
     Metropolitan  Square
     1450 G Street,  N.W.
     Suite 445
     Washington, D.C.   20005

     Ms.  Nancy  Kim
     Director
     Division of Environmental Health
      Assessment
     State  of New York  Department of Health
     Center for Environmental Health
     2 University Place
    Albany,, New York   12203-3399

    Mr. Albert F.  Appleton
    Commi s s ioner
    New York City
    Department of Environmental Protection
    59-17 Junction Boulevard
    Elmhurst, New York: 113731-5107

    Mr., Eric c. Mather
    Petro Environmental, Incorporated
    9267 Cincinnati-Dayton Road
    West Chester,  Ohio  45069
                               2-4

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        TABLE 2-1.
 Docket item numbera
 D-19
LIST OF COMMENTERS ON PROPOSED NATIONAL
 EMISSION STANDARDS FOR HAZARDOUS AIR
  POLLUTANTS FOR  SOURCE CATEGORIES:
   PERCHLOROETHYLENE EMISSIONS FROM
        DRY CLEANING FACILITIES
              (CONTINUED)

             ========        	
            Commenter and affiliation
 D-20
D-21
D-22
D-23
     Ms.  Connie L.  Deford
     Environmental  Affairs
     Chemicals & Metals
     Dow  U.S.A.
     2020 Dow Center
     Midland,  Michigan  48674

     Ms.  Katy Wolf
     Executive Director
     Institute for  Research and Technical
      Assistance
     3727 West 6th  Street, Suite 505
     Los  Angeles, California  90020

     Mr.  W. Caffey  Norman, III
     Patton, Boggs,  &  Blow
     2550  M Street, N.W.
     Washington,  D.C.   20037

    Mr. William  Juris
     Engineering  Section
    Division of Air Pollution Control
    State of Ohio Environmental Protection
      Agency
    1800 Watermark Drive
    Columbus, Ohio  43266-0149

    Mr.  John Gove
    Principal Air Pollution Control Engineer
    Bureau of Air Management
    State of Connecticut Department of
      Environmental Protection
    165  Capitol Avenue
    Hartford,  Connecticut  06106
                               2-S-

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        TABLE 2-1.
LIST OF COMMENTERS ON PROPOSED NATIONAL
 EMISSION STANDARDS FOR HAZARDOUS AIR
  POLLUTANTS  FOR SOURCE  CATEGORIES:
   PERCHLOROETHYLENE EMISSIONS FROM
        DRY CLEANING FACILITIES
              (CONTINUED)
 Docket item number?
                                Commenter and affiliation
 D-24
 D-25
D-26
D-27
D-28
D-29
     Ms.  Margaret M.  Round
     Program Analyst
     Northeast States for Coordinated
       Air Use Management
     85 Merrimac Street
     Boston,  Massachusetts  02114

     Ms.  Deborah A.  Sheiman
     Resource Specialist
     Natural  Resources Defense Council
     1350 New York Avenue,  N.W.
     Washington,  D.C.   20005

     Mr.  Richard A. Valentinetti
     Director
     Vermont  Air Pollution Control  Division
     Agency of Natural Resources
     103  South Main Street,  Building  3  South
     Waterbury,  Vermont  05671-0402

     Mr.  William L. Weissler
     President
     Diversitron  Corporation
     61-37  Fresh  Meadow Lane
     Fresh  Meadows, New York  11365

    Mr. Marvin Rosenstein.
     Chief
    Pesticides and Toxic Substance Branch
    U. S.  Environmental Protection Agency
    Region I
    J. -F. Kennedy Federal Building
    Boston",, Massachusetts;   02203-2211.

    Ms. Margaret M.  Round
    Program Analyst
    Northeast States for Coordinated
      Air Use Management
    85 Merrimac Street
    Boston, Massachusetts  02114
                               2-6-

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         TABLE 2-1.
                          °F C°MMENTERS ON PROPOSED NATIONAI
                                                            L
                                            E CATEGORIES:
                        PERCHLOROETHYLENE EMISSIONS FROM
                              DRY CLEANING FACILITIES
                                   (CONTINUED)
                                 Commenter and affiliation
Docket item number3
^—«—P^«™.


D-30
 D-31
 D-32
 D-33
D-34
L-l
                        Mr. James D. Boyd
                        Executive Officer
                        Air Resources Board
                        1102 Q Street
                        Sacramento, California  95812

                        Mr: William E.  Fisher
                                      Fabricare Institute
                        Silver Spring,  Maryland  20904

                        Mr.  Peter D.  Robertson
                        Patton,  Boggs,  &  Blow
                        2550 M Street,  N.W.
                        Washington, D.c.   20037-1350

                        Mr.  James  D.  Boyd
                        Executive  Officer
                        Air  Resources Board
                        1102 Q Street
                        Sacramento, California  95812

                       Ms. Nancy Kim
                       Director
                       Division of Environmental Health
                         Assessment
                       State- of New York Department: of Health
                       Center for Environmental Health Heaith
                       2 University Place
                       Albany,  New York  12203-3399

                       Mr. Rob Raney
                       Division Engineer
                       Division of. Pollution  Control
                       Metropolitan Government of
                        Nashville and  Davidson County
                       3ii-23rd Avenue, North
                       Nashville,  Tennessee  37203
                              2-7

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        TABLE 2-1.
LIST OF COMMENTERS ON PROPOSED NATIONAL
 EMISSION STANDARDS FOR HAZARDOUS AIR
   POLLUTANTS  FOR SOURCE  CATEGORIES:
   PERCHLOROETHYLENE EMISSIONS FROM
        DRY CLEANING  FACILITIES
              (CONTINUED)
 Docket item number3
            Commenter and affiliation
 L-2
L-3
L-4
     Mr.  Edward O. Sullivan
     Deputy Commissioner
     New York State Department of
       Environmental Conservation
     50 Wolf Road
     Albany, New York  12233

     Mr.  Peter D.  Robertson
     Patton, Boggs,  & Blow
     2550 M Street,  N.W.
     Washington,  D.C.  20037-1350

     Mr.  Michael  A.  Nash
     Senior Counsel
     Minnesota Mining and Manufacturing Co
     Post Office  Box 33428
     St.  Paul,  Minnesota  55133-3428
L-5
L-6-
L-7
    Ms. Barbara Warren
    Project Coordinator
    NY Toxics Project
    Consumer Policy Institute
    101 Truman Avenue
    Yonkers, New York  10703-1057

    Mrv, Robert-D.. Fletcher, Chief
    Toxic Air Contaminant Control Branch
    Stationary Source Division
    State of California
    Air Resources Board
    2020 L Street
    Sacramento,  California  95812

    Ms., Katy Wolf
    Executive Director
    Institute for Research and Technical
      Assistance
    2800 Olympic Blvd.,  Suite 101
    Santa Monica,  California  90404
                               2-8

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        TABLE 2-1.
                         QT™OMMENTERS °N PROPOSED NATIONAL
                     EMISSION STANDARDS FOR HAZARDOUS AIR
                      POLLUTANTS FOR SOURCE CATEGORIES:
                       PERCHLOROETHYLENE EMISSIONS FROM
                            DRY CLEANING FACILITIES
                                  (CONCLUDED)

                                               	
                                Coinmenter and  affiliation
L-8
                        Mr. Frank Kean
                        Kean's The Cleaner
                        9323 Mammoth Avenue
                        Baton Rouge/ Louisiana
70814
aThe docket number for this proiect is A-SS-Ii
 on file at EPA Headquarters^^WashJngton? D*c.
                              2-9

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    2.1   SELECTION OP POLLUTANTS


 stratosphere ozone depletion      0
 sale these chemicals and     '         ""
 these chemicals.
                                                    offeri"9
  using these   lvents
                                 *
                               e to purchass
     This cbmmenter recognized that
authority under the clea! iir AcT*A
reconditioned CPC-113 unconvertible
                                                          °* ""'"


                                                           •••
 authority to do so.            "achxnes,  if the  EEA has the
                                             that
 Pointed out that   e         ce
 standards that vill control e^ions      l.





regulation =ou!d have, the:                          "  " """
stratospheric
                              2-10,

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 inconsistent with section 604(c) of the Act, which provides for a
 scheduled phasing out in the production and consumption of
 Class I ozone depleters.
      Response;  There are several reasons for not regulating
 CFC-113.   It is used less commonly than PCE because it is a less
 aggressive cleaning solvent than PCE and it is more expensive.
 As reported in a 1989 dry cleaning survey,  only 6 percent of the
 plants responding to the survey had CFC-113 machines.   They used
 them for  special cleaning purposes, such as to clean leather.
 Although  CFC-113 may be well suited for cleaning special items,
 in general,  it may not clean other types of clothing as
 efficiently as PCE.   Moreover,  the use of CFC-113 has  been
 declining in recent years.
      As the commenter mentioned,  because CFC-113 is not listed as
 one of the 189 HAP's in section 112(b)  of the Act,  the EPA does
 not have  the authority under the dry cleaning NESHAP to regulate
 the use of CFC-113 or equipment associated  with its use.
 However,  as  the commenter pointed out,- the  use of CFC-113  is
 being regulated elsewhere in the Act.   Under Title VI,  CFC-113 is
 scheduled to be phased out  by the year 2002 because of its
 contribution to stratospheric ozone depletion.
      There are several reasons  for not regulating 1,1,1-TCA dry
 cleaners.  As discussed in  the  proposal preamble,  there are. only
 about 50  dry cleaning facilities  in the United States  that are
 known to  use 1,.1,1-TCA,. and all of  these facilities, use equipment
 to  control the emissions- from these machines.   The  higher  cost of
 1,1,1-TCA (about  $15  per gallon compared to about  $3 per gallon
 for PCE in 1989)  gives  owners or  operators  an  incentive to extend
 their, solvent mileage through, the use of- emission control  to
 recover and  reuse 1,1,1-TCA.  As  a  result,  the  national emissions
 of  1,1,1-TCA from: dry cleaners  are  low  (380 Mg/yr or less),
 representing only about  0.1 percent  of the  total annual 1,1,I-TCA
 emissions of  336,000  Mg.,
     Similar  to CFC-113, the  chemical 1,1,1-TCA is also being
phased out by the year 1996 due to its contributions to
 stratospheric, ozone depletion.  It also has aggressive  properties

                              2-11

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 making it an unsuitable solvent for most dry cleaning purposes.
 For these reasons, 1,1,1-TCA is unlikely to be the solvent of
 choice for dry cleaning owners or operators purchasing new
 machines.
 2.2  SELECTION OF AFFECTED FACILITY
 2.2.1  Collocation
      Comment;   Four commenters (IV-D-22, IV-D-25,  IV-D-26,
 IV-D-28)  recommended that the criteria for determining a major
 source be based on the entire dry cleaning facility instead of
 each dry cleaning machine.  One commenter (IV-D-28)  stated that
 the definition of source used in the proposed NESHAP refers only
 to the consumption of PCE for an individual machine.   This
 commenter  pointed out that by using this proposed  definition of
 source only certain machines would be considered major sources.
 This commenter believed that the collective consumption of  PCE
 should be  considered from all machines located within a
 contiguous area under common control.
      One commenter (IV-D-22)  noted that the exemption criteria
 given in paragraphs (b)  and (c)  of section 63.320  of  the proposal
 regulation are stated in terms of the amount of PCE  consumed per
 year by machine,  but the exemption was established based on
 annual receipts by facility.   The commenter pointed out that
 because a  facility can have more  than one  machine, the exemption
 criteria should be stated on a facility basis.
      Three' commenters (IV-D-25, IV-D-26, IV-D-28)  pointed out
 that a potential  problem could arise with  the proposed definition
 of  source  when a  dry cleaning facility has more  than  one  machine
 located in the same  building.  The  commenters emphasized  that
 each, machine individually may not be a major source;  however,
when combined,- the machines could consume  enough PCE  to be
considered  a major source..  Using the  proposed definition of
source, these  commenters explained that  (in this particular case)
each machine would be required to meet  only generally  available
control technology  (GACT) instead of maximum achievable control
technology  (MACT).  One commenter  (IV-D-26) asked what would
happen  if a dry cleaning operation has 4 dry-to-dry machines",

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  each  consuming  1,000  gallons  of PCE per year.  The  commenter
  pointed  out that  such a  facility under the proposed rule would
  not have to apply MACT to these units, only the less stringent
  GACT, even though total  PCE consumption by the facility as a
  whole would exceed the cutoff for a major source.
      One commenter (IV-D-24) requested that special permit
  conditions be given to facilities that operate each machine at
  levels less than  the  applicability thresholds, but which have the
  potential to exceed such thresholds in total.
      Response;  The final rule has been revised to base the
  applicability of  the  standard on the average aggregate annual PCE
  consumption of all machines located at a dry cleaning facility
 calculated on a monthly basis.  The definition of a major source
  in the Act includes sources "located within a common area and
 under common control."  Because multiple units located at a
 single dry cleaning facility would be under common control,  the
 applicability of this NESHAP for major sources has been revised
 to be consistent with the language of the Act.  The final NESHAP
 has also  been revised to define an area source on a facility-wide
 basis rather than a machine basis when determining solvent
 consumption levels.   This approach was selected to ensure
 consistency and  to simplify the rule.
      No special  permit requirements would  be  necessary  for
.facilities  with  multiple  machines.  All sources with only
 dry-to-dry  machines: using more: than 2,100  gallons  of PCE  per year
 would  be  required  to meet MACT whether one machine or several
 machines  are located at that source.   All  other sources using
 more than 1,800  gallons of PCE per year would  also be required to
 meet MACT,  regardless  of  the number of machines located at that
 source..   In,addition,  all. sources must maintain monthly records
 of their  consumption and;  calculate their: average annual PCE
 consumption on a monthly  basis.
     In the proposed NESHAP, the applicability of  the standard
 was based on the annual PCE consumption of an individual dry
 cleaning  machine.  Few dry cleaners, however,  have more than one
 machine per facility,   and the majority of facilities with more

                               2-13

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  than one machine are the larger commercial and industrial sized
  dry cleaners.  Few, if any/ of these larger facilities are
  affected by revising the definition of applicability because each
  machine used at these larger facilities would consume more PCE
  than the low consumption exemption.
       It is possible that a dry cleaning facility with two
  machines that would have been subject to GACT under the proposed
  rule may now be subject to MACT,  considering their total PCE
  consumption.   it is also possible that a dry cleaning facility
  with a  large  machine that is subject to MACT might also contain a
  small dry cleaning  machine  that would now be subject to MACT
  However,  these situations are uncommon and the overall  impact  of
  this  revision is minimal.
  2-2.2  Applicability Criteria
      Comment:   One  commenter (IV-D-25)  argued  that the
  applicability  criteria given in the proposal NESHAP for small
  existing area  source dry cleaners are illegal.  This commenter
  cited the legislative history from the Congressional »„„«.
              aU    ±t  h                * in the final
                                                       1"
      disapprove of EPA's
      measures  otherwise required.    •Lffl-LT:ai:ions °r control

 Based on  this  guidance,  the  commenter stated  that the EPA must
 apply its control  standards  to  all  existing area  source  dry
 cleaning  machines, regardless, of: solvent consumption: levels
      Response:  The Act  clearly states, that all major sources  are
 to be regulated under MACT standards.  Area sources,  however,  may

 *" rTatSd "^ GACT  ^ thS  f inal rUle USeS GACT< rathir- than
MACT, to regulate area sources.  The Act provides the
Administrator some discretion in regulating area sources under
GACT.  For example, the Act does not state that every area source
                              2.-14:

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 within an area source category must be regulated.  In determining
 GACT for area sources, the low solvent consumption exemptions
 were established on the basis of cost versus benefits and
 economic impacts.  The smallest sources were exempt from
 regulation because, in the .-judgment of the Administrator, the
 balance between the costs and benefits of regulation, along with
 the economic impacts in terms of business closures and financial
 failures were considered unreasonable.
 2.2.3  Exempting Coin-Operated Facilities
      Comment:  Two commenters (IV-D-23, IV-D-25) stressed that
 coin-operated (coin-op)  facilities should not be exempted from
 the NESHAP.   one commenter (IV-D-23)  believed,  however,  that
 these facilities should be given special requirements.   This
 commenter pointed out that the State of Michigan specifies
 minimum requirements for supervision,  ventilation,  operation,  and
 maintenance  of coin-op facilities.
      The other commenter (IV-D-25)  pointed out  that,  by  not
 choosing to  "list"  coin-op machines,  the EPA proposed to exempt
 whole classes of dry cleaning machines.   This commenter  added
 that public  exposure is  especially  high from these  types of dry
 cleaners, which are typically found in laundromat settings.  This
 commenter added that people,  often  accompanied  by young  children,
 may spend several hours  a  week in these  settings.   This  commenter
 explained that  laundry workers, and their children, may  be
 present  for many hours each day, particularly at. family-owned
 cleaners.  This commenter  added that these facilities may be
 located  in shopping centers with stores,  restaurants, and offices
 nearby.
     This commenter cited  the criterion in section  112(c)(3):
     The, Administrator shall list under this: subsection each
     category or subcategory of area sources which the
     Administrator  finds presents a threat of adverse
     effects to human health or the environment  (by such
     sources.• individually or in the aggregate) warranting
     regulation under this section.
The commenter explained that coin-op machines satisfy this
criterion and must be regulated.   The commenter argued that the
                               2-15

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 EPA cannot rely on future trends to address a current public
 health concern.  The commenter stated that since 47 percent of
 coin-op machines are currently controlled, the EPA must establish
 MACT-based emissions control achieved by the best 12 percent of
 existing sources in this subcategory.
      Response;  Considering aggregate PCE emissions of coin-op
 dry cleaning facilities from a national perspective, these dry
 cleaning facilities do not present a threat of adverse effects to
 human health or the environment.  The PCE emissions from these
 facilities, on a national level, are 900 Mg/yr.   Compared to the
 overall PCE emissions of 84,600 Mg/yr from the PCE dry cleaning
 category as a whole,  coin-op facilities represent about 1 percent
 of nationwide emissions.  Because the PCE emissions from these
 facilities are so low,  they do not warrant regulation under this
 NESHAP.   If,  however,  local authorities feel that coin-op dry
 cleaning facilities present problems in certain  situations,  then
 nothing in the NESHAP prevents these authorities from adopting
 local  ordinances  to address these problems.
 2.3  EMISSION CONTROL TECHNOLOGY
 2.3.1   Refrigerated Condensers
     Comment;   One  commenter (IV-D-02)  stated that the  standards,
 as currently  written/ do not allow  industrial dry-to-dry machines
 to use refrigerated condenser vapor recovery devices.  This
 commenter  asserted  that  a PROS refrigerated condenser
 manufactured  by his. company,  if properly sized, would; be able to
 cope with  these large machines and  should, therefore, be included
 as an  option  for vapor recovery.
     Response;  The proposed NESHAP did not prevent industrial
 dry-to-dry, machines at. major sources from using refrigerated
 condensers.  Previous information from dry cleaning machine and
 control equipment manufacturers indicated that there were no
refrigerated condensers being used to, control PCE emissions from
 industrial dry cleaning machines.  Information provided by the
commenter and an industrial dry cleaner trade association
following proposal indicates that there are industrial sized
refrigerated condensers; in operation at dry cleaning facilities.

                               2-re

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      In addition,  information available since proposal  from  a
 data base compiled from a survey of approximately 2,000 dry
 cleaners conducted by the California Air Resources Board  (CARB)
 reveals that the solvent mileage achieved in actual practice by a
 refrigerated condenser is greater than that achieved by a carbon
 adsorber.  Solvent mileage is the ratio of clothes cleaned to the
 amount of solvent  consumed.  Although air emissions are only one
 of several factors that determine solvent mileage, significantly
 better solvent mileage is indicative of lower air emissions.
 Consequently, this new information lends the EPA to conclude that
 refrigerated condensers achieve significantly lower air emissions
 in actual practice than carbon adsorbers.   Because a refrigerated
 condenser results in lower air emissions,  all new and
 uncontrolled major source dry cleaning machines are required by
 the final standards to install refrigerated condensers.
      Comment:  One commenter (IV-D-27)  believed that the cost of
 a  refrigerated water chiller should be included in the cost of
 operating a  refrigerated condenser.   The commenter noted that
 cooling water for a refrigerated condenser must be below 75  OF to
 keep the  condenser operating properly.   He added that plants  that
 use recirculating water  towers to comply with  local  ordinances  or
 to conserve  water to  minimize-sewer  costs,  and  that  are  located
 in areas that are hot and humid, will not  have  inlet  water below
 75 OF.  The  commenter explained  that they  would  be forced to
 operate- with, a refrigerated water chiller.
     Response;  The range in  the costs of  refrigerated condensers
 used in the  cost  analysis is  quite broad and one reason  for this
 is that this range  reflects the  costs associated with
 refrigerated condensers without water chillers,  as well  as
 refrigerated condensers with-water chillers.  The capital costs
 estimates of a refrigerated condenser range from $6,300  to
 $10,800, and the annual operating costs range from $1,670 to
 $2,800.  The standards, .however,  do-not require  the use  of a
water cooled refrigerated condenser, and the condenser could be
water or air cooled.
                               2-17

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      Comment;  One commenter (IV-D-27) submitted data to support
 his claim that refrigerated condensers achieve less than
 95 percent reduction in PCE emissions when applied to a
 dry-to-dry machine and less than 85 percent reduction in PCE
 emissions when applied to a transfer machine system.
      Response;  As with any piece of equipment, a refrigerated
 condenser may be poorly operated.  For example, if the owner or
 operator does not operate the refrigerated condenser to achieve
 maximum performance (such as cooling to 45 °F)  then it is very
 likely it would not achieve high control  efficiency.   The
 NESHAP,  however,  requires the owner or operator of a dry cleaning
 system to operate and maintain the dry cleaning system,  as well
 as its emission control equipment,  according to the
 manufacturer's specifications and recommendations.   Such
 operation will ensure that refrigerated condensers achieve the
 high emission control efficiencies they are capable of achieving.
 2'3'2 Additional Requirements  for Hamper Enclosures and Room
       Enclosures
      Comment;   One commenter (IV-L-02)  felt that additional
 requirements  for  hamper enclosures  and room enclosures should be
 given in the  final regulation.   The commenter suggested  the
 following:  exhaust velocities,  typical local exhaust  volumes to
 properly ventilate the  room,  and exhausting the enclosures  to an
 air  pollution  control device that achieves  5  parts  per million
 (ppm)  or less.
      Response;  The unique  circumstances  of each  dry cleaner,
 such as  the size  of the room, size  and  location of  dry cleaning
machine(s), as well as the  type  of  dry  cleaning system(s),
 including the ancillary and.emission control  equipment used will
determine design  and operating-parameters,  such as;  exhaust
velocities.  It is-not possible, to  include  specific  and detailed
design and operating requirements,  such as those mentioned by the
commenter, in standards, which would apply to all dry cleaners
under all circumstances without exception.
                              2-18

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 2.3.3  Transfer Machine System Emissions
      Comment:  One commenter (IV-L-03) disagreed with EPA's
 estimate that nearly one third of all PCE emissions from transfer
 machine systems occur during the clothing transfer step between
 the washer and the dryer.  This commenter stated that they are
 currently gathering data to measure the PCE loss during transfer;
 however, this work has not been completed.  The commenter stated
 that once completed,  the data would be shared with EPA.   One
 commenter (IV-L-07)  stated that the worker exposure levels and
 the PCE emissions are higher for transfer machine systems than
 for dry-to-dry machines.
      Response;  Due to the wide variation in operating
 circumstances, there is substantial uncertainty in the emissions
 estimates from transfer machine systems,  and variation both above
 and below the estimates used for an average transfer machine
 system can be expected.   It is  estimated  that an uncontrolled
 transfer machine system on average emits  a total of 9.0  Ib of PCE
 per 100 Ib of articles cleaned.   The emissions from the  clothing
 transfer step are estimated to  be 2.5 Ib  of PCE per 100. Ib of
 articles cleaned.  Based on these estimates,  approximately
 one-fourth (25 percent)  of the  PCE emissions from transfer
 machine systems occur  during the  clothing transfer step  between
 the washer and the dryer.
     The EPA  agrees that the PCE  emissions  from uncontrolled
 transfer machine  systems are greater than; the  PCE  emissions from
 uncontrolled  dry-to-dry  machines.   In addition,  the EPA  agrees
 that the  clothing  transfer  emissions from a  transfer machine
 system  contribute  to worker exposure levels.
 2.3.4   Fugitive Emissions
     Comment:  One commenter  (IV-D-26) contended that because
 about half of the  PCE emissions at a dry cleaning facility are
 fugitive emissions, the NESHAP should control emissions from all  '
processes at a facility rather than only those from a particular
piece of equipment.
     Response;  There are two types of PCE emissions at dry
cleaning facilities:   process vent emissions and fugitive

                              2-19

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 emissions.  Process vent  emissions will be reduced  by
 requirements for process  vent control devices.  Fugitive
 emissions will be reduced by requirements to implement pollution
 prevention practices, such as leak detection and repair, the
 proper handling of cartridge filters, and storing all PCE and
 wastes that contain PCE in solvent tanks or containers with no
 perceptible leaks.
 2*3*5  Occupational Safety and Health Administration's
        Permissible Exposure
      Comment;  One commenter (IV-D-27) refuted the EPA's
 statement that transfer machine systems could not meet the
 Occupational Safety and Health Administration's (OSHA's)
 permissible exposure level (PEL) of 25 ppm and submitted data to
 support his claim.  This commenter also cited data showing
 operator exposure from unvented dry-to-dry machines at 200 to
 300 ppm during unloading and asserted that these types of
 machines will have difficulty meeting the prescribed OSHA levels.
      Response;   As the commenter stated,  it is possible for
 transfer machine systems to achieve the OSHA PEL if the owners
 tighten work practices and increase room ventilation.   in fact,
 claims  have been made that as many as 40  percent of existing
 transfer machine systems are currently meeting this requirement.
      As the commenter mentioned,  it is also possible that some
 dry-to-dry, machines, may have difficulty meeting, the prescribed
 OSHA  levels.. Nothing in the, NESHAP,  however,  affects, the ability
 of  a  dry cleaner or any dry cleaning  machine to  meet the  OSHA
 PEL.
 2 • 3 • 6   Diversitron Solvafc-in^® System
     Comment;.  One, commenter  (IV-D-27) submitted, data to support
his claim that the Diversitron Sol vat ion® System is capable of
achieving greater than 99 percent reduction in PCE: emissions.  He
added that the capital cost of. a Solvation® System can be as low
as $6,000.
     This commenter listed several advantages of the Solvation®
System over carbon adsorbers, explaining that steam for carbon
                              2-20

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 adsorber regeneration requires a minimum of 227 gallons of water
 whereas a Solvation® System uses about 20 gallons.  The commenter
 stated that each time a carbon adsorber is desorbed, between
 4 and 8 gallons of contaminated separator water are generated.
 The commenter added that, in some localities,  this contaminated
 water cannot be routed to a sewer and must be picked up by a
 hazardous waste disposal company at a considerable cost.  The
 commenter claimed that the Solvation® System generated far less
 contaminated water.
      The commenter further explained that carbon adsorbers
 require a fan motor to be run throughout the day.   The commenter
 explained that Solvation® System motors run only during the
 deodorize/aeration and open door cycles,  after which the motor is
 turned off.   The commenter noted that this results in no
 additional electricity cost.
      The commenter also claimed that plants that have replaced
 carbon adsorbers with Solvation® Systems  report an increase in
 solvent mileage ranging between 30  and 60 percent,  and a
 commensurate reduction in PCE purchased.
      The commenter added that the size, weight,  and design of  the
 Solvation® System would eliminate rigging costs  ($300  to $700);
 eliminate large,  custom ductwork costs ($300 to  $1,000);  and
 reduce floor space requirements to  2.5 square  feet.  The
 commenter also  stated that electrical  or  self-contained  plants
 without  the  boiler capacity required for- a  carbon adsorber
 (3.5  to  4.5  horsepower)  could be  controlled with a  Solvation®
 System,  which requires only fractional boiler  capacity.
      Response;  As  discussed in the volume I background
 information  document  (BID),, data  show  that a carbon adsorber is
 capable  of achieving  emission control  efficiencies well  in excess
 of 95 percent under optimal testing conditions.  It is not
 surprising, therefore, that some data  is available showing, a
 control efficiency of 99 percent for the Diversitron Solvation®
 System with an integral carbon adsorber under certain conditions.
The central question, however, is not what level of performance
this emission control equipment is, capable of achieving under

                               2-21

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 some short-term .idealized period of operation, but what level of
 performance this equipment is capable of achieving under normal
 operating conditions over the long term.
      The data submitted by the commenter suggests only that if a
 Diversitron Solvation® System is equipped with a small integral
 carbon adsorber it may be capable of achieving levels of
 performance equivalent to those achieved under optimal testing
 conditions by a large carbon adsorber alone.  However, there
 remain questions whether the Diversitron Solvation® System, as
 currently sold,  includes a carbon adsorber or not and, if so,
 exactly how this carbon adsorber is operated.  Questions also
 remain concerning whether or not the Diversitron Solvation®
 System with its  small integral carbon adsorber can consistently
 achieve high levels of emission reduction over the long term or
 whether these levels can be achieved only under optimal,  test
 conditions.
      This question of long term performance is very important.
 Although carbon  adsorbers have been demonstrated as capable of
 achieving high levels of emission reduction under controlled,
 optimal testing  conditions,  it has  been  shown that such levels  of
 control are  difficult to duplicate  in  actual field practice over.
 extended periods  of time.   Data available from a survey by  GARB
 (representing approximately 2,000 dry  cleaners),  which was
 undertaken following proposal  of the NESHAP,  shows  that the
 solvent mileage, achieved in. actual, practice by a  refrigerated,
 condenser is much greater  (i.e., twice as much) than that
 achieved by a  carbon adsorber.  Although  air emissions are  only
 one of  several factors that determine solvent mileage,
 significantly better solvent mileage is indicative of  lower air
 emissions.
     This, commenter, however,- or any other manufacturer with a
technology capable of achieving levels of emission reduction
equal to MACT for major sources or GACT for area sources can
petition the Administrator for a determination of equivalency.
For an emission control system to be considered equivalent to the
emission control, systems required in the NESHAP, the petitioner

                               2-22

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  must provide, data adequate to demonstrate  that  the  technology is
  equivalent  in terms  of  long-term emission  control performance and
  does not have greater multi-media effects  than  the  use  of  a
  refrigerated  condenser.
       Comment;  One commenter  (IV-D-27) pointed  out  that the
  concentration of  PCE in the vent exhaust from a refrigerated
  condenser is  1,000 times greater than what the  Diversitron
  Solvation® System emits to  the atmosphere  and 200 times greater
  than what carbon  adsorbers  emit.  The commenter argued that
  allowing these high  levels  of PCE emissions negates the purpose
  of the regulation.
      Response:  Emissions from a vented dry-to-dry machine
 controlled with a refrigerated condenser occur  only when the
 machine door is opened at the conclusion of the dry cleaning
 cycle.  A fan is used to draw fresh air from the room through the
 machine door opening, venting the PCE remaining in the machine
 drum vapor space to the atmosphere in a matter of seconds.
 Consequently,  although the concentration of PCE in these vapors
 may be much higher than those from a carbon adsorber or a
 Diversitron Solvation® System, the volume of vapor is small and
 the quantity or amount of  PCE emitted to the atmosphere is  very
 small.
      As stated in  the previous response,  results from a  survey of
 dry cleaners conducted by  GARB indicated  that, in  actual
 practice, a refrigerated condenser achieves: much greater solvent
 mileage (twice as  much) than a carbon adsorber.  Although air
 emissions are  only one of several factors that determine solvent
 mileage, significantly better  solvent mileage is indicative of
 lower  air emissions.
     Without information about the flow rate and. the duration  of.
 the venting interval, in addition to  the PCE concentration if.  is
 not possible to determine the performance of the Diversitron
 Solvation® System  and compare it  to a refrigerated condenser or a
 carbon adsorber.
     Comment:  One commenter (IV-D-10) stated that, according to
the manufacturer of the Diversitron Solvation® Solvent Recovery

                               2-23

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  system,  a carbon adsorber is supplied as  an integral  part of that
  Solvation® System.   The commenter also related  that Diversitron
  has  not  manufactured the Solvation®  System  without a  carbon
  adsorber for over a  decade.   The  commenter  believed that  the data
  about the Diversitron Solvation®  System used in developing the
  NESHAP were outdated and requested that the EPA reevaluate the
  appropriateness  of considering this  technology  as MACT.
      Response;   if,  as  the commenter stated, an existing
  Diversitron Solvation®  Solvent Recovery System  is operated in
  conjunction with  an  existing carbon  adsorber that is  integral to
  its system  on an  existing major source  dry  cleaning machine, and
  if the existing carbon adsorber is properly maintained and
 desorbed according to the manufacturer's specifications, then the
 Diversitron Solvation® System may be equivalent to MACT for
 existing sources.  (Existing machines that already have carbon
 adsorbers are not required to replace these adsorbers with
 refrigerated condensers under the final rule).
      The information submitted by the commenter, however,  does
 not clearly show whether or not existing Diversitron  Solvation®
 Systems  always  operate with a carbon  adsorber.   At this time, it
 is uncertain whether an existing Diversitron Solvation® System
 installed on an existing dry cleaning machine would be equivalent
 to the requirements  of the NESHAP.  As mentioned earlier,
 questions remain about whether a Diversitron Solvation® system
 with  a_ small integral carbon  adsorber can  consistently achieve
 high  levels of  emission  reduction  over the long  term.   The
 commenter can petition the Administrator for a determination of
 equivalency with  the  requirements  of  the NESHAP; however,  the
 petitioner must provide  data adequate to demonstrate that  the
 technology is equivalent  in terms of  long-term emission control
 performance  and does  not have greater multi-media effects  than
 the use of a refrigerated condenser.
 2.4  MODIFICATION AND RECONSTRUCTION
     Comment:  One commenter (IV-D-28) noted that under the
proposal if  a source with a dry-to-dry machine consumes more than
220 gallons per. year of PCE or a source with; a transfer machine

                            •   2-24

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 system consumes more than 300 gallons per year of PCE, then that
 machine must comply with the requirements of the regulation
 within 90 days.                           f
      The commenter pointed out that the proposed regulation would
 allow the following situation:  A previously uncontrolled machine
 that increases productivity after the regulation is promulgated
 would be required to install a control device within 3 months,
 whereas an uncontrolled machine that becomes subject to the
 regulation once it is promulgated, would be allowed 36 months to
 install a control device.
      The commenter suggested that this situation could be avoided
 by introducing a definition for modification in section 63.321 of
 the proposal regulation.  The commenter recommended that
 section 63.325(d)(2)  of the proposal regulation be rewritten to
 read:

      Each owner or operator who commences modification such that
      ™durfn9 any year the existing source consumes more than
      830  liters per year (220 gallons per year)  of
      perchloroethylene  for a dry-to-dry machine or 1,100 liters
      per  year (300 gallons per year)  of perchloroethylene for a
      transfer machine after (date of publication of the final
      rule),  then the  source owner or operator shall comply with
      the  requirements of section 63.322(a)  or section 63.322(b)
      within  X months  or by the compliance date specified in
      section 63.322(e),  whichever is later.
 The  commenter added that the  X months  should be  a  reasonable
 amount of time  for the  source to  install  controls.
     Response;   The EPA agrees that  an  inequity  existed under  the
 proposed NESHAP  since a  facility  previously  subject  to  the  low
 consumption  exemption would be allowed only  3 months to comply
 with the regulation, where other  facilities were given  up to
 3 6 months..  As suggested, by the, commenter, the standards have-
 been revised to require that existing facilities that are not
 required to  install control equipment initially, but may later
 expand their business sufficiently to become subject to the
requirements, are given more time to comply with the NESHAP.  The
final rule requires that they achieve compliance either within
180 days of the date that they determine that they are exceeding

                               2-25

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  the consumption levels or 36 months after the date of
  promulgation in the Federal  i^l^r,  whichever date  is  later
  The 36-month time  period for initial compliance is given to ail
  sources to allow for the increased  demand for control devices
  Sources exceeding  the consumption levels  after the initial 36-
  month time period  given for  all sources to comply  will be
  monitoring their PCE consumption levels and the demand for
  control devices  will be much lower  as  during  the initial 36-month
  compliance period.
      comment;  One  commenter (IV-D-14) noted  that part of the
  following phrase in the proposal preamble  is  incorrect:
                       be made at these Cdry cleaning]
       o  TO «        may be deemed Construction under
      40 CFR 63.5.  For example, replacement of either the
      washer or dryer would be considered a reconstruction.
 The commenter estimated that a typical transfer machine washer
 costs $12,000 and a dryer costs $6,000, for a total transfer
 machine system cost of $18,000.  The commenter pointed out that
 although it is true that replacement of a washer will exceed
 50 percent of the fixed capital cost required to construct a new
 source,  replacement of the dryer would not and,  therefore, would
 not be considered a reconstruction.   The  commenter added that
 without this clarification,  replacement of a transfer dryer alone
 would result in the required installation of a dry-to-dry
 machine.
      Response:   The intent of the reconstruction provision in the
 proposed standard was  to ensure that  any  facility that replaces
 either the washer or the dryer  unit in  a  transfer machine system
 would be considered a  new  source and  would  be  required to comply
 with  the applicable; MACT: or GACT requirements, for new  sources,,
 Therefore, replacement of either the  washer or dryer would be
 deemed reconstruction.  Under the final NESHAP, no emissions are
 allowed  for new sources between washing and drying,  in effect
this means that when either the washer or dryer needs to be
replaced, the owner or operator must purchase a new dry-to-dry
                              2-26

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 machine.  The purpose  is to avoid prolonging the use  of existing
 transfer machine systems.
      Comment:  one cpmmenter  (IV-D-14) recommended that the EPA
 make it clear that a machine below the low solvent consumption
 exemption level is not affected by reconstruction.  The commenter
 argued that dry-to-dry or transfer machine systems should retain
 their exemption status as long as their PCE consumption levels
 remain below the low solvent consumption exemption level.
      Response;  During the regulatory development process, the
 EPA concluded that an exemption from installing process vent
 control devices for facilities with very low solvent consumption
 was warranted for existing sources,  but that no exemption was
 warranted for new sources.   Because the dry cleaning standard has
 no low solvent consumption exemption levels for new sources,  a
 source of any size (including one below the low consumption
 exemption for existing sources)  that undergoes reconstruction
 would be subject to the standards for new sources.
 2.5  ECONOMIC IMPACTS

      Comment;   Two  commenters  (IV-D-16,  IV-D-24)  expressed
 concern that the economic impacts discussed in the  proposal omit
 estimates  of the increased cost  of health care for  persons
 adversely  affected  by PCE emissions  from  dry cleaners.  These
 commenters requested  that the  costs  of adverse  health  affects  be
 included in  the  economic analysis.
     Response;  The benefits of  emission  reduction  associated
 with a regulation,  if addressed, are discussed  in a benefit
 analysis as part of a regulatory impact analysis performed to
 comply with Executive Order 12291 for major regulations.  This
 proposal,, however, is. not; a major regulation, and no benefit
 analysis was undertaken.
 2.5.2  Control Costg
     Comment;  Two commenters  (IV-L-01, IV-L-05) disagreed with
the incremental cost of control for a dry-to-dry machine over a
transfer machine system given in the notice of availability of
new information on control of PCE emissions during clothing
                               2-27

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 transfer at dry cleaning facilities that use transfer dry
 cleaning machines.  One commenter  (IV-L-01) disagreed with the
 EPA's method for determining the incremental cost effectiveness
 of control for a dry-to-dry machine over a transfer machine
 system.  The other commenter (IV-L-05) stated that an assessment
 of the health risks associated with transfer machine systems was
 needed to put the control costs into perspective.
      Response;  The approach used by the first commenter to
 calculate incremental cost effectiveness underestimates annual
 control costs because several important cost factors were
 excluded..  The commenter excluded the amortization of capital
 costs,  indirect operating costs (e.g., insurance costs)  and
 solvent costs.  All of these factors were included in the EPA's
 determination of the net annualized costs.
      A NESHAP promulgated under section 112(d)  of the Act is
 based on MACT or GACT (i.e.,  demonstrated emission control
 technology)  and not on risk assessment.   Nevertheless,  the higher
 emissions from a transfer machine system were considered in
 examining the incremental cost  effectiveness of a dry-to-dry
 machine over a transfer machine system.
 2.5.3  Economic Considerations
      Comment:   One  commenter  (IV-L-07)  stated that reconditioned
 dry-to-dry equipment is available at a much reduced cost and
 suggested the  EPA use  those costs in its  calculations.
      Response;   The commenter suggested developing cost  estimates
 for replacement of  transfer machine systems with  dry-to-dry
machines  using  the  cost of reconditioned rather than new
dry-to-dry machines.   At this time, the cost of a reconditioned
dry-to-dry machine,  may: be lower than the,cost of  a new machine;
however,  it is  highly  questionable whether there  are a sufficient
number of reconditioned machines to meet the demand created by
replacing, transfer machine systems.  If demand increases, it is
likely that the price  of a reconditioned dry-to-dry machine would
increase and approach  the price of a new dry-to-dry machine.  For
this reason, it is more appropriate to base cost estimates on new
rather than reconditioned dry-to-dry machines.

                              2-28

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2.6  ENVIRONMENTAL IMPACTS
     Cosjment:  TWO commenters  (IV-D-Ol, iv-D-
concern about the wastewater impacts of the
                                                    expressed
                                                            One
                                                         ,

                                        The coxtnnenter
            system are not insignificant.

  thTZT ^ ^ ^ rSeValUate          -ntation costs of
  the dry cleaning NESHAP, taking into consideration the costs of
  transferring PCE fro, air emissions to wastewater
       One commenter (IV-D-10)  reported that it is the

               the regulation.                    Practice be

      ResEonse:  As stated in the preamble to the
 and^th.commenters, noted, the, total amount of ast
 effluent from refrigerated condenser or carbon adsorber




 typical, existing, dry-to-dry machine with a carbon adsorber
                                         O.S5
                               	***  waouewctcer generate
             condenser  is very small.   A.typical  existing
         . machine with a refrigerated  condenser  <
process vent generates  about 0.03 kg  (0.07 lb) of
wastewater per year.

                               2-29

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  dry cleanxng machines  however,  will be required to install
  refrigerated condensers.   Therefore                 install

          owner may dispose of PCE contaminated wastewa    at an
 approved hazardous waste faciXity consistent witn aPPLable
condenser.  Moreover, whether the smaW anount of
           1  routed to
               One counter (IV-D-18)  requested  clarification


-------
      This commenter questioned whether cartridge filters from the
 dry cleaning industry may be thrown into the trash once they have
 been drained or dried for 24 hours.  He also questioned whether
 these filters are considered an F-002 waste or other similar
 waste under 40 CFR 261.31.
      Response:  As stated in the preamble to the proposal NESHAP,
 all PCE containing waste generated at a dry cleaning facility
 subject to the Resource Conservation and Recovery Act (RCRA) must
 be treated as a hazardous waste as specified under RCRA.  Note
 that PCE containing waste generated at a dry cleaning facility
 includes spent carbon,  used cartridge filters,  PCE containing
 lint,  etc.
      Nothing in the regulation permits PCE containing waste
 generated by dry cleaners,  including drained cartridge filters,
 to be thrown into the trash.   Oftentimes,  however,  a dry cleaner
 may qualify as a conditionally exempt small quantity generator if
 the dry cleaner generates no  more than 100 kilograms of hazardous
 waste  per month and may be subject to less stringent requirements
 under  RCRA.
 2.7  SELECTION OF MAXIMUM ACHIEVABLE CONTROL TECHNOLOGY AND
     GENERALLY AVAILABLE CONTROL  TECHNOLOGY
 2.7.1   Regulatory Considerations
     Comment:   Five  commenters  (IV-D-10, IV-D-14, IV-D-24,
 IV-D-25,  and  IV-D-26) remarked on the use  of MACT versus GACT  for
 regulating dry  cleaners.  Four of these commenters  (iv-b-io,
 IV-D-24,  IV-D-25,  and IV-D-26) believed that MACT should be  used
 to  regulate all dry  cleaners, and one commenter  (IV-D-14)
 believed  that GACT was the appropriate method for regulation.
     One  commenter  (IV-D-25) believed that given the high public
 exposure  to air toxics caused,by dry cleaners, regulation of all
 categories, of dry cleaners under MACT is necessary.  This
 commenter maintained that MACT standards offer greater protection
 of public health, now, and in the future, and should be adopted
for all categories of dry cleaners.  This commenter quoted the
Congressional Record to illustrate that the regulation of certain
                              2.-31

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 categories and subcategories as area sources is optional under
 the amended Act:

      The Administrator can also list an area source category
      }ust as he would a major source category and require
      installation of maximum achievable control technology.
      Two commenters (IV-D-24, IV-D-26)  believed that there is
 sufficient and compelling health effects information regarding
 PCE to warrant application of MACT to all dry cleaning machines
 regardless of type or size.
      One commenter (IV-D-10)  acknowledged that section 112(k)  of
 the Act outlines a comprehensive strategy to reduce HAP's from
 area sources.  However,  this commenter  believed that such a
 strategy would not reduce PCE emissions sufficiently from area
 source dry cleaning facilities.   The commenter believed small  .
 existing dry cleaning facilities that have less than
 state-of-the-art controls will adversely impact human health and
 the environment.   For this reason,  the  commenter believed that
 section 112(c)(3),  (i.e.,  a threat  to human health and the
 environment  by sources individually,  or in the  aggregate)
 warrants the application  of MACT controls  for all  area source  dry
 cleaners.
     Two commenters  (IV-D-25,  IV-D-26)  asserted that residual
 risk review  should be  required for  all  dry cleaners  to ensure
 that public  health is  adequately protected.   One commenter
 (IV-D-26) argued  that  it  is, bad, public:  policy to define, the vast-
 majority of  dry cleaning  facilities as  area  sources  and apply
 GACT to  them, thus precluding a residual risk assessment at a
 later date.  Based on the knowledge gained in the Northeast
 States, on public  exposure to PCE from dry cleaning facilities,
 this commenter maintained that it is absolutely necessary that
 such a risk assessment be conducted for this source category.
     One commenter (IV-D-14) stated that GACT instead of MACT  is
the appropriate control level, of PCE emissions from area sources.
This commenter referred to the citations from the Senate
Committee Report given in the preamble and also cited additional
legislative history to support: his, point.  This commenter stated

                               2-32J

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 that each of the three Senators (Senator Symms, senator McClure,
 and Senator Moynihan) who spoke on the Act amendments mentioned
 dry cleaners as one of the groups for which GACT was appropriate.
      Response;  As stated in the proposal, the EPA has concluded
 that area source dry cleaners present a threat of adverse effects
 to health or the environment.  For this reason, commercial dry
 cleaning facilities that are area sources were added to the list
 of source categories under section 112(c)(3)  to be regulated
 under the Act.  Listing an area source category under
 section 112(0(3),  however,  does not require that regulations
 developed for this  source category must be based on MACT.   These
 regulations may be  based on MACT or they may be based on GACT.
      The EPA does not agree with the commenters who believe the
 health effects information regarding PCE is so compelling that  it
 warrants application of MACT to all small area source dry
 cleaners.   As stated by the  Science Advisory Board,  "[t]he
 available scientific evidence confirms that perchloroethylene •
 should be considered as an animal  carcinogen  ...  [however]  we
 do not consider the evidence strong enough to classify this
 compound as a probable human carcinogen .  .  .  .»
      During development of the regulation,  the EPA  concluded  that
 many  small  area source dry cleaning facilities may  experience
 adverse economic impacts  as  a result of  imposing a  regulation
 based  on MACT.   For this  reason, the GACT  approach was selected
 as  the  basis  for regulating  small  area source  dry cleaning
 facilities.
     Although a residual  risk analysis is required for sources
 regulated under MACT, those  sources  regulated under GACT may  also
 receive  a residual risk analysis.  Section 112(f) (5) of, the Act
 merely  states that residual risk analysis is not required  for
 area sources regulated with GACT;  it does not preclude area
 sources  from a  residual risk analysis.
     In  addition, as mentioned by one of the commenters,
 section  112(k)  of the Act directs the EPA to develop a strategy
to control HAP  emissions from area sources in urban areas.  The
strategy, among other things, must achieve area source emissions

                               2-33

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 reductions from the 30 HAP's that pose the greatest threat to
 public health and achieve at least a 75 percent reduction in
 cancer incidence from all stationary sources.  Consequently, the
 need for emission controls beyond GACT at dry cleaners will be
 reconsidered in the context of the overall urban air strategy and
 the relative contribution of PCE emissions from dry cleaning
 facilities to urban exposures.
      Finally, as pointed out by one commenter, much evidence
 exists in the Senate Committee report and the legislative history
 of the 1990 Clean Air Act amendments, that dry cleaning was
 considered an example of an area source category for which
 regulations based on GACT were appropriate.
      Comment:  One commenter (IV-D-24)  disagreed with the
 conclusion given in the proposal preamble that,  for economic
 reasons,  it is unreasonable to apply MACT to all sources.  The
 commenter stressed that existing State  requirements have been
 successfully implemented on the dry cleaners that the EPA
 proposes  to exempt.   The commenter added that the reduction in
 solvent usage (in some cases,  a 50 percent reduction has been
 reported)  and associated savings have a net  pay  back period of
 2  to  3  years.
      Response;   The  economic analysis conducted  prior to proposal
 serves  as  the basis  for the conclusion  that  it is  unreasonable to
 impose  MACT on area  source dry  cleaners.   Unlike the. MACT
 approach: for major sources, which: specifies  a regulatory floor
 (i.e.,  minimum regulatory requirements),  the  GACT  approach for
 regulating area  sources  specifies  no  regulatory  floor.
 Development of  any GACT  requirement,  therefore,  takes  into
 consideration the costs: and economic; impacts  as well as..-other-
 potential  impacts associated with  its requirements.  For  this
 reason, GACT  for area sources, represents, a balance between
 economic,   energy, and environmental impacts.  This consideration
 is particularly important when regulating area source dry
cleaners because the majority of these facilities are small,
family-owned businesses that could be severely impacted by
regulatory requirements.

                               2-34;

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   current «tT                          e      -ntation of
   current state  requirements are not available;  however   as
   discussed  in the proposal preamble, analysis of the  Impacts
   associated with implementation of the standards with T^
   solvent consumption exemption levels estimates a potential
   20 percent closure rate for small dry cleaning facilitie"
   impacts  of this magnitude are considered unreasonable
       Analyse of the solvent savings associated with controlling
   emissions from the small machines exempted by the low solvent

                        level  show  toat solvent              "
                 Four commenters (IV-D-lo, lv-D-24  IV-D
  IV-0-26)  believed, that Regulatory Alternative   i,  Ihe
  ctt?^ rS9Ulat°ry alt-"ati- ^iven in the proposal
  controlling process vents, should be selected to control
  tTans'feTJT "" eXiSt±n9 ^ "" ^^-^ -"
  transfer machine systems.
      gesponse;  At proposal,  Regulatory  Alters i™, TT
                                           "

tnsr
transfer
               ar
               area source transfer machine systems and carbon
                  ol tprocess vent smiss-ions fL -      r
                  systems,  was selected as the basis
=
                                                 r:r
.,.              »                              ;; -:::.
flcilitiesT / r*^  °£ aPPr°XiMte^ 2'°°° *y cleaning
facilities conducted by  CARS.  This information reveals that
solvent mileage achieved., in actual practice by
                              2-35

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  condenser is much greater than that achieved by a carbon
  adsorber.  Although air emissions are only one of several factors
  that determine solvent mileage,  significantly better solvent
  mileage is indicative of lower air emissions.   The new
  information leads the EPA to conclude that refrigerated
  condensers achieve significantly lower air emissions in actual
  practice than carbon adsorbers.
       The final NESHAP,  therefore,  requires existing uncontrolled
  transfer machine  systems at  area sources  to install and operate
  refrigerated condensers.   The Administrator considers  the
  additional costs  of  replacing existing carbon adsorbers with
  refrigerated condensers,  however,  to  be unreasonable.   As a
  result,  existing  transfer machine  systems  already controlled by
  carbon adsorbers  are not  required  to  replace their  carbon
  adsorbers with refrigerated condensers.
      Comment;  One commenter  (IV-D-24)  stated that the proposal
 NESHAP does not consider using the authority of section  112(a)(1)
 of the amended Act to consider dry cleaners that emit less than
 10 tpy to be major sources based on the potency of the HAP,
 persistence, potential for bioaccumulation, or "other
 characteristics of the air pollutant,  or other relevant factors "
 This commenter realized that the EPA has not established
 guidelines yet for determining lesser quantity emission rates
 (LQER's).  However,  this commenter believed that PCE satisfied
 the criteria, for establishing a LQER,  particularly with regard  to
 the inherent toxicity of PCE,  its high potential for
 bioaccumulation, and  the extensive public  exposure to PCE that
 has been  documented in the vicinity of dry cleaning  facilities
 The commenter cited these factors to support applying MACT to all
 sizes; of  dry cleaning;machines.
     Responses Section  112(a)(1) of the Act is  a discretionary
provision.   The EPA has  the authority  to develop LQER's  for some
hazardous, air pollutants  "on the  basis of the potency of  the air
pollutant, persistence, potential for bioaccumulation, other
characteristics of the pollutant, or other relevant factors •'
The methodology for evaluating the need for and the approach for

                               2-36

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 establishing LQER's  is  still under  development.   If  an LQER
 ultimately  is adopted for  PCE,  then the  dry cleaning NESHAP will
 be  reviewed and  revised, as appropriate.
 2.7.2  Determining Threshold of Threat of Adverse Effects
     Comment;  One commenter  (IV-D-24) responded  to  the EPA's
 request  for comments on the appropriate  threshold for  determining
 whether  a particular source category or  subcategory  presents a
 threat of adverse effects  to health or the environment sufficient
 to  warrant  regulation.  This commenter argued that although the
 EPA stated  that  this finding is required in the absence of  an
 area source strategy, the  following direction exists (according
 to  the commenter) in the amended Act:
     This study  was  not intended to replace or diminish
     regulation  of area sources, particularly in  the case of
     dry cleaners
 and
     provides  that the  requirements to develop area  source
     strategy  shall  not be interpreted to preclude or  delay
     implementation  of  action with  respect to area sources
     of  HAP's  under  consideration pursuant to the  Clean Air
     Act that  may be promulgated before  the strategy is
     proposed.
 Based on this  citation, this commenter stressed that Congress did
 not intend  for the urban area source strategy to be  the sole
 vehicle  for regulating  area sources.  This commenter further
 stated that economic impact analysis alone or national  impacts of
 emissions reductions  do not permit  the appropriate evaluation of
whether  an area  source presents an  adverse threat to human  health
 or the environment.   This  commenter argued that in determining
 the, health impacts of area sources,  the inherent toxicity of the
HAP and  the exposure potential of the population living in  the
vicinity of the  source must be considered.   This commenter
concluded by saying that exposure conditions must include a
characterization of the fate and transport of the HAP once  it is
released from the source and activity patterns of the exposed
population.
                               2-37'

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      Response;  The EPA agrees with the commenter that the urban
 area source strategy was not intended to be the sole vehicle for
 regulating area sources.  The EPA is proposing to regulate PCE
 dry cleaners,  most of which are area sources,  prior to the
 completion of  the urban area source strategy.
      In order  to regulate a category of area sources under
 section 112(d),  a finding must be made that the category presents
 a threat of adverse effects to human health or the environment
 sufficient to  warrant regulation.   Therefore,  a finding of a
 threat of adverse effects was presented in the proposed rule for
 PCE dry cleaners.
      The fate  and transport of PCE emissions were not
 specifically addressed in this finding.   However,  the EPA
 believes that  available health effects information is sufficient
 to establish a finding of a threat of adverse  effects for the
 purpose of regulation under section 112(d).  Furthermore,  the EPA
 believes standards under section 112(d)  are  the appropriate first
 step and that  further controls (considering  fate and transport)
 may be appropriate after completion of the national  area source
 strategy required  by section 112(1)  of the Act.
 2.7.3   Indoor  Air  Pollution
      Comment:  Twelve commenters (IV-D-05, IV-D-08,  IV-D-10,
 IV-D-11,  IV-D-14,  IV-D-16,  IV-D-17,  IV-D-21, IV-D-23,  IV-D-24,
 IV-D-25,  IV-D-26)  had remarks  on indoor  air  pollution.   Ten
 commenters  (IV-D-05,  IV-D-08,  IV-D-10, IV-D-ll,  IV-D-16,  IV-D-17,
 IV-D-23,  IV-D-24,  IV-D-25,  IV-D-26)  expressed concern  about
 indoor  air pollution  from neighborhood dry cleaners  and  thought
 that the  standards did not  adequately  address this problem.   Five
 commenters, (IV-D-10,  IV-D-11,,  IV-D-16, IV-D-24,  IV-D-25) referred
 to a New  York  State study which  found high levels of PCE in
 residences located above dry cleaning  establishments.  These
 commenters urged the EPA to review this study.  The commenters
 believed this  study clearly indicates that the risk to public
health in such situations is significant and should be targeted
 for regulation.
                               2-38'

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      One commenter  (IV-D-05)  stated that the proposed NESHAP  does
 not reduce this  indoor air pollution problem and requested  that
 the standards be modified to  prevent these problems from
 occurring.  Another commenter (IV-D-11) mentioned that although
 the Act does not specifically address indoor air pollution,
 indoor air emissions eventually become ambient air emissions.
      One commenter (IV-D-14)  disagreed with the concern that the
 standards would  not adequately control air pollution by stating
 that the purpose of the Act is to address ambient air quality
 rather than indoor air quality.
      Response;  The EPA was unaware of the New York study and its
 findings of elevated PCE levels in residences located above dry
 cleaning facilities prior to proposal.   Many States and
 environmental groups,  however, referred to this study in their
 public comments on the proposed NESHAP,  and several commenters
 submitted copies of the report attached to their public comments.
 Subsequent discussions with the authors of the  report indicate
 that  the dry cleaning  trade associations are familiar with it.
 Nevertheless,  copies of the report were forwarded to these
 associations  to  ensure they were aware  of  it.   As a result,  the
 EPA believes  that most people  concerned  with PCE emissions from
 dry cleaning  facilities are  familiar with the study and, as  such,
 the study can  be  considered  common knowledge.
     The New York study indicates  that PCE emissions can
 accumulate  in  residences  located above dry cleaning  facilities,
 leading to  increased public exposure to PCE.  It  should be noted
 that PCE accumulation  in  buildings would not be  limited to
 residences located above  dry cleaning facilities.  In fact,  the
 New York study can be viewed as demonstrating that PCE emissions
 can accumulate in any building that includes a dry cleaning
 facility.
     While not definitive, in  EPA's opinion, several observations
 included in the New York study suggest that fugitive PCE
 emissions—not process vent emissions—may be the major
contributor to the elevated PCE levels in the apartments located
above the dry; cleaning facilities..  For example, process vent

                               2-39

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 emissions were generally released to  the  atmosphere at a point
 outside the dry cleaning facility,  yet  the  elevated PCE levels
 observed in the apartments were  essentially the  same whether the
 windows of  the apartments were open or  closed  during the study.
 This tends  to  discount  the contribution of  process  vent emissions
 to the  elevated PCE  levels.
     On the other hand,  observed PCE  levels in the  apartments
 located above  dry cleaning facilities with  transfer machine
 systems were significantly higher than  PCE  levels observed in
 apartments  above dry cleaning  facilities  with  dry-to-dry
 machines.   This tends to highlight the  contribution of fugitive
 emissions to the elevated PCE  levels, since fugitive emissions
 from transfer  machines  systems are much higher than those from
 dry-to-dry  machines  due to clothing transfer between the washer
 and the dryer  at transfer machine systems.   Also, equipment  leaks
 and generally  poor operation were observed  at  many  of the dry
 cleaning facilities, and these are  major  contributors to fugitive
 emissions.
     As a result, EPA reevaluated the costs and  benefits of
 extending those, provisions of  the proposed  standards  which
 focused on  fugitive  emission control  (i.e.,  the  pollution
 prevention  requirements)  to dry  cleaning  facilities below the  low
 solvent consumption exemption levels.  Such pollution prevention
 requirements include leak detection and repair,  and good
 housekeeping practices  such as keeping solvent tanks  and
 containers  covered while  not in  use,  and minimizing the  time that
 the doors on the dry cleaning machines remain open.   These costs
 were determined to be reasonable  based on the additional  emission
 reduction., achieved..  Thus:, in  the final., rule, all PCE  dry
 cleaning facilities  are required to implement pollution
prevention practices.  Such practices would help address the
 indoor  air problems  indicated by the New York study-
     Additional remedies to control indoor air emissions from PCE
dry cleaning facilities may also be necessary and appropriate.
Such remedies could be adopted on the Federal,  State, or local
 level..  At this time,, however,  the EPA is unsure of; what these

                               2-40

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 additional remedies might be.  Consequently, the EPA will
 continue to assess the problem highlighted by the New York study,
 try to identify additional remedies, and decide how best to
 proceed.
 2.7.4  Small Consumption Facilities
      Commenti   Six commenters (IV-D-10,  IV-D-ll, IV-D-16,
 IV-D-17, IV-D-23,  IV-D-25)  believed that the proposed low solvent
 consumption exemption levels would exempt existing area source
 dry cleaning operations that endanger human health.   One of these
 commenters (IV-D-ll)  stated that it is the small.volume area
 source facility that poses  the largest threat to individuals
 because many existing area  source dry cleaners are located in
 residential areas.   Another commenter (IV-D-25)  argued that,
 because of their location in proximity to human populations,  more
 people are exposed  to air toxics from small existing area source
 dry cleaners than from large industrial  complexes,  such as
 chemical plants, which are  not usually located in the midst of
 population centers.   Another commenter (IV-D-16)  believed that
 virtually all  small existing area source dry cleaners
 contributing to this  problem would be sources exempted under  the
 proposed NESHAP.
      Three commenters (IV-D-10,  IV-D-ll,  IV-D-23)  requested that
 the EPA reevaluate  the low  solvent consumption exemption levels
 to  ensure that  small  existing area source dry cleaning facilities
 located in or near  residences are  subject to  the  standards..
      One  commenter  (IV-D-17)  recognized,  that  although  the
 economic  impact of regulating the  small  existing area  source  dry
 cleaners  can be significant,  the process  and  fugitive  emissions
 from  these  sources can endanger human health.  This commenter
requested that, prior to promulgating the NESHAP, the  EPA examine
 low cost control technology and operating procedure alternatives
to reduce PCE emissions from  small existing area source dry
cleaners.
     Two commenters (IV-D-14, IV-D-22) recommended that small
existing area source dry cleaning machines exempted from the
                              2-41

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 regulation not be exempted from certain inspection and repair
 provisions.
      Response:  The Act provides the Administrator with a
 considerable amount of flexibility in regulating small area
 sources.  For the small area source dry cleaning category, GACT
 was selected as the vehicle for regulation consistent with the
 Senate Committee report on the Act, which cited dry cleaning as
 an example of a source for which GACT was the most appropriate
 vehicle for regulation.
      Standards developed under GACT represent the Administrator's
 judgment of a reasonable balance between the cost,  energy, and
 environmental impacts of alternative control technologies.  The
 objective of GACT is to achieve the greatest degree of emission
 reduction without imposing unreasonable impacts.   Because very
 small dry cleaners may suffer economic hardship if stringent
^regulation is imposed on them,  the cost,  economic and other
 impacts on these  sources were carefully evaluated.
      There are no low solvent consumption exemption levels
 included in the NESHAP for new area sources.   The final NESHAP
 requires all new  area source  dry cleaning machines  to control
 process vents,  clothing transfer emissions,  and fugitive
 emissions.
      Ml existing area source dry cleaning machines are required
 to control  fugitive  emissions.   Existing  area  sources  are  also
 required to  control  process, vents; except where the economic,
 energy,  and  environmental  impacts were  judged  to  be unreasonable.
At proposal these  impacts  were  judged to be unreasonable for area
 sources  consuming  less than 200 and 300 gallons of PCE per year
 for dry-to-dry machines and transfer machine systems,
respectively  (corresponding to annual receipts of $100,000).
      In response to comments, the EPA reconsidered the low
solvent consumption exemption levels for process vent control and
decided to lower them to 140 and 200 gallons per year,
respectively.  The cost effectiveness of process vent control at
these very small area sources ranges from $1,600 to $3,600 per
ton of PCE.  As many as 165 additional financial, failures  are

                              2-42;

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portion prevention pactices


     Additional remedies  to  control

Two commenters  (IV-D-20   iv-n


                       '
                                    -

the EPA.i.pose, a, ban on 4 th* sale of n'

systems in the futm-.    n   "
 JT   m=> J.H "cne ruture.   One commenter
                                               *
                                                 —onunended that


                                                tr*nsfe^
                             2^43

-------
        This commenter believed
                                       i.

                         -.
  recondxtxoned machine can be purchased for between Sis
                                     -
better capital  investment  ,or the dry cleaner      '      """ "
     Two counters  (IV-D-14 and IV-L-03) urged the EPA  to



appropriate to retire the purchase or dry-to-drTr^i^rat d


                              2-44,

-------
   to the   ™ted  the EPA to ban the  sale
  of both new and  used transfer machine systems,  adding that  both
  new and used transfer  machine systems are still  being offered for
                       *° Pr°P°Sa1'
that no new
 transr-                   '             -ed that no
 transfer machine systems were being sold or had been sold in
 Hel^H LearS.dUe ^ ^ adOPti0" °f ^ °^ P^ional Safety and
 Health Administration (OSHA, permissible exposure level (pL,  of
 25 parts per million (ppm)  for PCE (January 19,  1989)
 pcE tm rduoe worker exposure ievais-   Bas- « ^
 PCE emitted during the transfer step,  transfer machine  systems
 « blli   daS     PaWa °f meSting *"• °SHA PEL-   B«-~ ^e
 EPA believed no new transfer machine systems were being sold  it
 was not considered  necessary to develop  regulations  that    '
 eeel   **"***  " ^^^ «» "" * "- transfer machine
      Following proposal, however, the Eleventh circuit Appeals
 court remanded the PEL to OSHA.  This action could certainly slow
 the transition from transfer machine, systems, to dry-to-dry
 machines.                                                y

 ooeraf "" /1S° lMrned f°^°«^ proposal that many o^ers or
 operators of transfer machine systems, were meeting the OSHA PEL
 by increasing ventilation or rotating the placement of their
workers.  Moreover,  it was learned that  petroleum transfer
machine systems,  which are still being manufactured for use  with
                              2-45

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                                   „

                                                            new
                no  less
        source.  A  new transfer maohlne
enclosure represents the best control
However, M&CT may be more stringent if
the balance between the ^^^
env.ronmenta! impacts of a more stringent required is

                             2-46

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  uncontrolled transfer machine system.  The annualiZed costs  for
  such control would be a net savings  ($300) because overall PCE
  consumption is lower with a dry-to-dry machine.  This lower  cost
  x« due to the increased amount of PCE that is recovered and
  recycled within the machine.
       The EPA believes it is reasonable to require new transfer
  machine systems located at major sources to meet the same level
  of emission control achieved by new dry-to-dry machines.   Thus,
  the final NESHAP prohibits any emissions between the washing and
  dryxng step of the dry cleaning cycle for new transfer machine
  systems located at major sources.
       For new area source transfer  machine systems,  the NESHAP is
  based on GACT.   The GACT is  a balance between environmental
  economic,  and  energy  impacts the Administrator considers
  reasonable.  The  incremental cost  effectiveness  of requiring  a
  new dry-to-dry machine over a new  transfer machine system at  a
  typical new area  source  is approximately '$3,600 per ton.  The EPA
  does not believe  that the additional costs of purchasing a new
  dry-to-dry machine over purchasing a new transfer machine system
 would deter entry  (or expansion) into the dry cleaning market
 If a new business venture is viable and attractive with a new*
 transfer machine system,  the EPA believes that the business
 venture would be equally viable and attractive with a new
 dry-to-dry machine.  Consequently,  the impacts of requiring
 transfer machine systems, to eliminate all. clothing transfer
 emissions (i.e.,  purchase a new  dry-to-dry machine)  is considered
 reasonable.
        Commgni:   one commenter  (IV-D-25)  stated that  at one point
 durxng the  regulatory  development process,  the EPA was
 considering immediate  or  gradual replacement of  existing transfer
 machine  systems with new dry-to-dry machines.  This commenter
 noted that there was no mention of  existing transfer machine
 system phaseout in the proposed NESHAP.  The commenter stressed  -
that the EPA cannot rely Qn QSHA ^^ ^ accomplish &      t
phaseout of existing transfer machine systems.   The commenter
noted that OSHA's final rule contemplated an extension of the
                              2-47

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 deadline by which engineering controls would be required, if a
 trade association requests it.
      This commenter believed that the NESHAP should provide a
 schedule for the accelerated replacement of existing transfer
 machine systems with well-controlled dry-to-dry machines, and not
 simply rely on trends in the industry.
      Two commenters (IV-L-05,  and IV-L-06)  believed that all
 existing transfer machine systems should be phased out of use.
 One commenter (IV-L-05)  felt they should be phased out rapidly.
 One commenter (IV-L-06)  also recommended phasing out existing
 transfer machine systems "and believed that  MACT for all existing
 transfer machine systems is replacement with dry-to-dry machines.
      Response;   The requirement  for  existing transfer machine
 systems to be replaced with new  dry-to-dry  machines was a control
 option considered by the EPA prior to proposal  of the NESHAP.
 From a cost-effectiveness viewpoint,  there  is little difference
 in  the impacts  of requiring immediate replacement of existing
 transfer machine systems or gradual,  phased-in  replacement,   in
 both cases,  the capital  cost of  the  existing transfer machine
 system is a  "sunk"  cost  that has been incurred  and is not a
 factor in the analysis.
      This viewpoint makes  the  analysis  of replacing or phasing
 out  existing transfer machine  systems quite  different from that
 of banning or prohibiting  new  transfer  machine  systems.   For
 existing-transfer machine  systems, the  costs  of replacing or
 phasing  out  the  existing system  are the full  costs  of  a new
 dry-to-dry machine.  For a new transfer machine system, the costs
 of banning or prohibiting the  new system is the difference in
 costs  between,the new transfer machine  system and the, new
 dry-to-dry machine.  Consequently, the costs are much  higher in
 the analysis of replacing or phasing out; existing transfer  •
machine systems, than they are  in the analysis of banning  or
prohibiting new transfer machine systems..  The incremental cost
effectiveness for replacing or phasing out a typical area source
existing transfer machine system with a dry-to-dry machine is
approximately $41,800 per ton of PCE reduced.  The incremental

                               2-48

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 cost effectiveness for replacing or phasing out a typical major
 source existing transfer machine system with a dry-to-dry machine
 is approximately $12,200 per ton of PCE reduced.
      The high costs of either immediate or gradual replacement of
 existing transfer machine systems is considered unreasonable for
 both area and major sources.  No additional information has been
 presented to alter this conclusion.  Consequently, the NESHAP
 does not require replacement of existing transfer machine systems
 with dry-to-dry machines.
 2.7.6  Reclaimers
      Comment;  Five commenters (IV-L-02,  IV-L-03,  IV-L-05,
 IV-L-06,  IV-L-07)  agreed with EPA that use of a reclaimer with a
 dry-to-dry machine would make them a transfer machine system.
 One commenter (IV-L-07)  also wanted to ban the sale of new or
 used reclaimers.
      Response;   The NESHAP has been revised to define a
 dry-to-dry machine used  with a reclaimer  as a transfer machine
 system.   The NESHAP does not allow emissions to occur between  the
 wash and  dry cycles for  a new dry  cleaning machine.   This
 requirement effectively  bans or prohibits  new transfer machine
 systems.   It also  effectively bans  or  prohibits the use of new
 reclaimers  with new or existing dry-to-dry machines,  because
 adding a  reclaimer  to a  new  or  existing dry-to-dry machine
 creates a new transfer machine  system.
 2.7.7  Room Enclosures
     Comment;  One  commenter (IV-D-25) suggested that,  until
 transfer  machine systems are phased out, total vapor  containment
 (i.e., room enclosures) should be the control required  for all
 transfer machine systems.  The: commenter requested that transfer
machine systems be enclosed  to capture fugitive emissions and
 channel them to control devices.
     Two commenters (IV-D-10 and IV-D-24)  suggested that the EPA
evaluate a new type of total vapor containment exhaust and
control system (i.e., room enclosure) that has been retrofitted
to an existing transfer machine in New York State.   The commenter
                              2-49

-------
  stated that this control system should be considered MACT for
  transfer machine systems.
       Response:   As indicated in the previous  response,  the final
  NESHAP effectively bans  new transfer machine  systems.   At the
  commenters'  suggestion,  the EPA reconsidered  requiring  room
  enclosures  on existing transfer machine systems.  Room  enclosures
  capture and vent the fugitive PCE emissions to a carbon adsorber.
  Because clothing transfer emissions  are a  significant portion of
  overall transfer machine system emissions, control of these
  through a room enclosure would  achieve  additional emission
  reductions.
      The only type of control device that could effectively
  control PCE emissions on a room enclosure is a carbon adsorber.
 As stated previously, however, new information emerged following
 proposal indicating that in actual practice within the dry
 cleaning industry, carbon adsorbers achieve a much.lower level of
 emission reduction than originally thought.
      Assuming,  for the sake of discussion,  a carbon  adsorber
 achieves a 95 percent reduction in PCE  emissions,  the incremental
 cost effectiveness of requiring room enclosures with carbon
 adsorbers on existing major source transfer machine  systems would
 be as low as $300 per ton of PCE.  In fact,  even  if  the  control
 efficiency of the carbon  adsorber was as low as 10 percent,  the
 incremental  cost  effectiveness of requiring room enclosures on
 major source transfer machine systems would be about $3,600 per
 ton.
      Although the EPA does not believe the  control efficiency  of
 carbon  adsorbers  within the  dry  cleaning industry is  as  low as
 10 percent, making such;an assumption for the purpose of
 calculations; effectively indicates-that, even at low control
 efficiencies, the: use of room enclosures: at major source transfer
machine  systems is reasonable.  Consequently, the final NESHAP
requires the use  of room enclosures with carbon adsorbers at
existing major source transfer machine systems.
     Requiring existing major source transfer machine system dry
cleaners to use room enclosures is not estimated to result in any

                              2.-50

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additional financial failures or- ^
limited number of vendors of V  Cl°SUreS'  **tlally, due to the
          with                  * enclosure^  the EPA was
              250
 enclosures were r
         systems
         s
 requirement on only the
 receipts over $100
      enclosures,
area sources.

2'7*8  Hampe
                                                only for the
                                               r iiures
                                               *r«n such a
                                       transfer machine system
                           2-51

-------
 with the room enclosure during the transfer step and an exhaust
 ventilation rate (such as 100 linear feet per minute inward air
 velocity)  should also be required.
      Response;   The use of both a hamper enclosure and a room
 enclosure together is not estimated to reduce PCE emissions from
 the clothing transfer step by any more than a room enclosure
 alone.   Little  additional PCE reduction is estimated because the
 hamper  enclosure would be located inside the room enclosure.
      Comment;   One commenter (IV-L-05)  believed that the use of
 hamper  and room enclosures should not be limited to new machines
 because loans and leasing arrangements are made available by
 major equipment manufacturers for small businesses.
      Response;   The availability of loans Or leasing arrangements
 was not an issue in determining the reasonableness of requiring
 hamper  or  room  enclosures.   Rather,  the concern was  the price of
 such control devices in a monopolistic market created by
 regulation when there is only one supplier (with a patent)  of the
 devices.   This  situation could cause the price of such control
 devices to increase significantly if the widespread  use of these
 controls were mandated by the NESHAP.
      Comment;   One  commenter (IV-L-03)  believed that transfer
 enclosures (e.g., hamper and room enclosures)  would  not be
 economically feasible for existing area sources.   This commenter
 added that with a great demand for hamper enclosures,  their price
 could increase  substantially-above the  current price of $3,000.
 The  commenter added that the same would occur  with room
 enclosures,  as  they would also likely be sold  in  a monopolistic
 market.  Two commenters (IV-L-02,  IV-L-05), however,  stated that
 economic concerns about the  creation of  a monopolistic market
 were  overstated..
      Response;   Initial  concerns  about  the-emission-reduction
 achievable, costs,  and  availability of hamper  enclosures and room
 enclosures made  them unreasonable  for area source  dry  cleaning
machines.  In response  to the  comments, however, the EPA
reconsidered requiring room enclosures on existing major sources.
As discussed elsewhere, the. final NESHAP requires room  enclosures,

                               2-52

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  on existing major source transfer machine systems-those located
  in a dry cleaning facility with an annual PCE consumption of. more
  than 1,800 gallons).  By limiting this requirement to major
  sources, the demand for room enclosures is relatively small and
  is unlikely to lead to excessive price increases.
       Although two commenters believed the economic concerns
  associated with requiring hamper enclosures or room enclosures
  may be overstated,  these commenters offer no reasoning or logic
  to explain why they believe that to be the case.
  2*7'9  Additional Controls for
       Comment:   TWO  commenters  (IV-D-25,  IV-D-27)  stated  that
 additional controls should have been considered for dry-to-dry
 machines.  One  commenter  (IV-D-25) mentioned a new German
 machine, the Permac Consorba®, that uses a carbon adsorber in
 conjunction with a  refrigerated condenser for vent control   The
 commenter pointed out that this machine was mentioned in the
 background document as achieving 98 to 99 percent control, but
 was not evaluated further.  The commenter stated that it made
 sense that a dual control system would achieve better control
 than a machine with one control device.  The commenter felt that
 this control was not evaluated sufficiently and quoted the
 Congressional
                      ^
      assure that he has - collected data oS 5! o
            ~P   Ofming sources within each category
                  dat*t
     Another commenter  (IV-D-27) stated that emissions to  the
atmosphere from dry-to-dry; machines, with refrigerated: condensers
are Hmxted to the opening and closing of the loading door.  This
commenter pointed out that some States, such as New Jersey
determined that emissions from dry-to-dry refrigerated condenser
controlled machines would exceed the levels prescribed in their
rule.  These machines have installed mini-carbon adsorbers to
reduce PCE emissions for a capital cost of about $3,000.   The
                              2-53;

-------
 commenter suggested that the EPA should evaluate the use of such
 devices and consider requiring them.

      One commenter (IV-D-25) discussed the "floor" as described
 in section 112(d)(3)  of the amended Act:

      Emission standards...shall not be less stringent, and
      may be more stringent than the average emission
      limitation achieved by the best performing 12 percent
      of the existing sources...(emphasis added by commenter)

 The commenter quoted an explanation by the author of this
 section,  which appeared in the Congressional Record;

      Subsection(d)  specifically authorizes the Administrator
      to go beyond  the floor if he determines that a more
      stringent standard is achievable.   Indeed, the
      Administrator is authorized and expected to set the
      standard beyond  the level achieved by any source in the
      past if he determines that such a  standard will be
      achievable by the deadline for compliance.  The
      fundamental test is not whether the standard is at or
      above the average for the best performing 12 percent of
      the  sources in the category,  but whether the standard
      reflects the  maximum  degree in reduction of emissions
      that can be achieved  by sources in the category.

 This  commenter argued that MACT for existing dry-to-dry machines
 should  consider  the use of supplemental control systems,  such  as

 carbon  adsorber  add-ons to a refrigerated condenser machine.   The
 commenter stated that this approach should be evaluated to

 determine if  it  can achieve better  levels of  control for existing
 sources.

      Response;   In  the simplest sense,  a  Permac Consorba®. may  be
 described as  a dry-to-dry machine equipped with two  control

 devices in series—a  refrigerated condenser followed by  a carbon
 adsorber.  The reported advantage of this  system over a

 conventional  dry-to-dry machine, equipped with only a refrigerated
 condenser  is:  that the  Permac Consorba® reduces  the PCE

 concentration in the air remaining  in the machine once the dry
 cleaning cycle is complete;

     With a conventional dry-to-dry machine equipped with a
refrigerated condenser, the air is saturated with PCE at the end

of the dry cleaning cycle.   With the Permac Consorba®, because
                              2,-54

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 air  in  the machine  is  lower   an'      °°ncentrat^» °f PCE  in  the
     Tha Pennac Consorba«^s^lL theBsaturati°" concentration.
 m other words, when the door L opM'T^ ^"'^ ^™-
dry cleaning cycle, no fan turns on t  „       <*»***•**» of tha
dry cleaning machine and »ven^ the Ich
conventional dry-to-
  a vent.  Consequently
  ary-to-dry
  releases all the PCE
  the

                                                        through
                                  «*"9«ated condenser
                                                             to
                                                            ;;
refrigerated condenser
                               -*-*«
                                             equipped vlth
 opened,  the Permac Consor    has
 than a conventional dry-to-
                                              ***
- release of the
machine at the conclusion of the dry"  le
is opened.                       "^ Oleanin9
                                           =y=le when the door
                           2-55

-------
       These emissions can be controlled by drawing the air
  remaining in the machine through a small carbon adsorber either
  before the door to the machine is opened (similar to the Permac
  Consorba ) or venting the air through a carbon adsorber when the
  door is opened,  indeed, several vented dry-to-dry machines
  equxpped with refrigerated condensers currently operate in this
  manner (i.e.,  the air remaining in the machine is vented to a
  carbon adsorber).   There is no difference in PCE emissions
  between a Permac Consorba* and a vented dry-to-dry machine
  equipped with  a refrigerated condenser and  a small carbon
  adsorber on the vent.   Similarly,  there would be no difference  in
  emissions between  a Permac  Consorba-  and a  conventional  no-vent
  dry-to-dry machine equipped with a refrigerated  condenser that
  passed the air  remaining in the machine at the end  of the dry
  cleaning  cycle  through a carbon adsorber before  the  door to the
  machine was opened.
      Under the Act, MACT for new major sources must  be no less
  stringent than the best-controlled similar source.  AS a result
 the final NESHAP requires that new major source dry-to-dry
 machines be equipped with a refrigerated condenser and that the
 air remaining in the machine at the end of the dry cleaning cycle
 be passed through a carbon adsorber prior to opening the machine
 door or that  the air remaining in the  machine be passed through  a
 carbon absorber as  soon as  the door to the machine is opened.
 Thus,  the level of  control  required, for major new source  dry
 cleaning  facilities is  equivalent to that achieved by the Permac
 Consorba®  technology.
     The MACT is also required  for existing dry-to-dry machines
 located at major sources.  Under the Act, MACT for existing
 souroe...»ust be, no, less stringent than,the level  of control
 achieved by the best 12 percent'of existing sources.  Less than
 12 percent of existing major source dry-to-dry machines are using
 a refrigerated condenser in combination with a carbon adsorber to
 control PCE process vent emissions.   However, MACT can be more
stringent if the Administrator determines that the balance of
                              2-56

-------
   effectiveness of the
                                                  cost
  condenser to also  install
  of ar               ii
                                            with * refrigerated
          XMey $per
   major source dry-to-dry machine located « a

  effectiveness vould    even             "^ ™ts> ' *h« «•*
  of Control is o^ite high
  reduction benefit achiLd  tn  ~
  of control reasonable  f« ant^L  d"
  at a major source           ««*mg dry-to-dry fflachine located
                                                   °f

 over the use of a
 per ton of PCS ir
 -control ef^ici
 is achieving a lower
 i^ental cost
result,  the EPA does not consider this
                                                    adsorber
                                                      518,500
                                                 ••
                                                carbon adsorber
                                                      «-
                                                    "* "
     ^offiffierit:  TWO commenters (lv-D-23  TV n ,«,
vapor barriers be required to nr-    !          }  requested that
          --=»>"
                            2-57

-------
   all floors, walls, and ceiliner« *•«
   -» .,..,_    '            ceilings to separate the dry cleaning

   facility from other areas in the building
                                                         *or .dry
               of
               of a. vapor barrier  in  a  30  by so  by 20  foot dry

  clearing facility would cost approxl                      **
                Four counters (IV-D-10, iv-D-23, IV-D-24
                                               ,
     one connenter  (1V-D-10) requested that specific  local


general exhaust or ventilation reo.ire.ents aL
                               2-58

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                  the NKPA
             (199° edition) •
          —
                     .» ...„.,
or
                  rr =- -
    s that prevent or control fugitive
    r -irr=.— • -


installlng        -
        2-59

-------
  requirements.  Moreover,  where local  authorities  consider
  ventilation systems necessary,  the NESHAP does not prevent  or
  hinder local agencies in  any way from requiring additional
  measures such as ventilation systems.
       As mentioned earlier, the NESHAP requires the implementation
  of a leak detection and repair program, as well as other
  additional pollution prevention measures, to control fugitive PCE
  emissions at all dry cleaning facilities.  These measures will
  achieve a substantial reduction in fugitive emissions at dry
  cleaning facilities.
       Comment:   One commenter (IV-L-01) referred to guidance for
  nonattainment  areas in 1979 that suggested  carbon  adsorbers be
  installed on all  dry  cleaning  facilities, regardless  of their
  size.   This commenter  stated that because this  level  of control
  was considered reasonably  available control technology  (RACT)  he
  questioned how anything  less stringent could be considered MACT.
      MsEonse:  The guidance concerning reasonably available
  control technology  (RACT)  issued in 1979 was just  that-guidance
  to States concerning the emission control performance and  costs
  associated with the use of carbon adsorbers as a means of
 reducing PCE emissions from dry cleaning facilities.  The basic
 objective was to provide States a source of information for use
 « developing state Implementation Plans (siP's).   The guidance
 was not a rule  or a regulation,   states did  not have to adopt
 regulations as  part of their SIP^ based, solely; on this  guidance
 tht !! °ne .I™1*  6XPeCt'  ^ regUlations  *d°Pted  in response to
 this the guidance  vary from State to State.
     On the other  hand, a NESHAP is a uniform national rule.   The
 factors considered in developing a NESHAP  are somewhat different
 from: those considered in  developing; guidance.  As a result,  it is
 not surprising that the NESHAP differs,  to  some- extent  from  the
 guidance, just as the rules developed by states differ from the
 guidance.

the rff^f  T° °°menters <™-°-2«.  IV-D-25, requested that
the regulation include appropriate restrictions on selling Used
dry cleaning machines to ensure that these machines are subject
                              2-60

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  to MACT or GACT requirements,  one commenter (IV-D-25)  thought
  that the EPA should prohibit the sale of old machines.
       Response:   The NESHAP does not exempt used dry cleaning
  machines.   The  NESHAP applies MACT or GACT to a dry cleaning
  machine depending on whether the source is a major source or an
  area source.  All major sources (whether they use  original or
  used equipment)  must meet MACT,  and all area sources (whether
  they use original or used equipment)  must meet GACT.
       Prohibiting the sale of old machines just because they are
  old  is  unreasonable,  with proper operation and maintenance,  old
  machines can operate as well,  in terms  of PCE emissions,  as new
  machines of the  same type and will  be required  to meet the  same
  emission control  requirements.   No  basis  exists, therefore,  to
  restrict the sale of  used equipment.
      Comment;  One commenter  (IV-D-25)  identified one pollution
 prevention option for industrial dry cleaners that he believed
 the EPA did not consider:  water wash and detergent.  The
 commenter asserted that this alternative, which can eliminate
 emissions altogether, should have been considered as MACT.
      Response;   Water wash and detergent is a poor substitute for
 PCE in many instances.  Water may be an effective alternative to
 cleaning certain types of clothes; however, there are many
 fabrics—notably wools and silks—that can not be cleaned
 effectively in water.  Other solvents,  such as PCE,  must  be used
 in  the Design for the Environment Program, the EPA  is evaluating
 the economic feasibility and performance of a potential
 alternative wet  cleaning process,  which  does not use PCE.
      For the most part,  water is  not a substitutable alternative
 for PCE.  in some cases,  as noted in the background,information
 document,for the  proposed  NESHAP,  industrial, sized machines  are
 switching over to  water wash  because water can be used
 effectively to clean  linens and uniforms.   However, this is  only
 one small portion  of the dry  cleaning industry and this situation
has limited applicability.
     Comment;;  One commenter  (IV-D-27) thought that no-vent
dry-to-dry machines should not be allowed as a control option in

                               2-61

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   an inward draft of
                                           *""
                                                          to

                                                             20° to
          regulations.
          oo,
               :  The NESHAP does not
           and



comnenter
                                                     one
consumed.
     This commenter added
                                     than the amount of PCE
                                          ,

                             2-62

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  whether affected  facilities  qualify for this  exemption/  they haye
  to keep records of the pounds of  clothes cleaned.   The counter
  stated that since most facilities usually weigh and record  the
  amount of .clothes loaded into their machines  to avoid
  overloading, this additional recordkeeping for exempted
  facilities would  not be burdensome.
       Three commenters (IV-D-24, IV-D-25, iv-D-26)  stated that
  they do not support the low solvent consumption exemption levels
  -the proposed NESHAP because there is no adequate documentation
  given to explain how these exemption levels were selected
       One commenter (IV-D-24)  asserted that PCE consumption rates
  alone are  not  a valid surrogate for determining PCE emissions
  from  dry cleaning  machines.   This  commenter pointed out that PCE
  x. released during the dry  cleaning process  from uncontrolled
  vents and  exhaust  pipes, auxiliary equipment that  is used to

  !ndT dl* diSt111 *"" PCE' eVaP°ration  d-in* Clothing transfer
  and handling, and  equipment leaks  during solvent transfer and
  from  stored solid  waste.  The commenter  stated that  relatively
  small, improperly  operated machines  have  the potential to  emit
 more PCE than well-controlled, industrial dry  cleaning machines
 and,  for this reason, PCE consumption rates should not be used as
 a surrogate for PCE emissions when determining which dry cleaners
 are major sources.                                         -«.««aners

 0-  p'^f22^1   AnnUal PCE ^^P^on is a reasonable indicator
 of, PCE emissions,   it: is, considered a better indicator of  PCE
 emissions than  the  amount  of clothes cleaned at a facility
 because it  is a  more  direct  measure of PCE emissions

 emitt'd ^/^  Cleanin9 Pr°CeSS' a11 °f  thS  S°1Vent c"* i-
 emitted either as process vent emissions,  fugitive  air emissions
 or contained in  solid; or liquid wastes.   Air- emissions of  PCE   '
 (process plus fugitive) represent, from  65  to  75 percent of PCE
 consumption; the remaining 25 to 35 percent of  PCE  is lost
 through PCE  contained in wastes.  Therefore, a  reasonably  direct
wLahTT "^ betWeen PCE ~a™**» «" ™ emissions.
Weighing the amount of clothes cleaned would not give as accurate
an indication of the resulting" PCE emissions or how well the
                              2-63

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cleaning facilities may weich ea!h ^  !      Although some dry
«... ~«. „ „„. r.«t ;"„':" "'"°- ••--' «

=

          „.
                    „

                    2-64

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  sentence of section 63.320(d) of the proposed NESHAP  is not
  necessary and should be deleted.
       BesEonse:  The low solvent consumption levels in the NESHAP
  are based solely on the amount of PCE consumed at a facility and
  have no relation whatsoever to the size of the dry cleaning
  machine.  Therefore,  to avoid any confusion that may occur from
  sectxon 63.320(d)  of the proposal regulation,  which refers to
  machine size,  this provision was deleted in the final rule
       As discussed in the preceding comment, PCE emissions  front a
  dry cleanmg machine  are most directly related to PCE
  consumption.   Machine  size is not an accurate  predictor of PCE
  consumption  or emissions.
       comment:  TWO  commenters (IV-D-13  and  IV-D-15) requested
  clear guidance on the  EPA's  interpretation  of  "potential to emit"
  because  it would impact the  major source or area  source
  distinction for future section 112 standards.
       These commenters argued that a source's "potential to emit"
  should be based on actual historical emission data and not on
 theoretically projected emissions assuming continuous operations
 One commenter (IV-D-13) urged the EPA to clarify that all
 controls used to reduce emissions would be considered in
 determining a source's "potential to emit."
      Both commenters cited statutory language,  the legislative
 history  of the  Clean Air Act as amended,  and recent court
 decisions to  support: the interpretation that a  source's
 "potential to emit"  is  based on actual  historical  operating
 conditions and  after application  of  installed controls.
      First, the commenters  quoted the definition of  "major
 source" from  section 112 (a) (i).  of the Act to include sources
  that  emit or has, the, potential to emit, considering controls "
     Second, the commenters turned to: the legislative history

and P^r fT ^ RSPOrt °f ^ S6nate C0mmittee °n
and Public Works on S. 1630 (1989) to further support their
interpretation that potential to emit should reflect actual
operating conditions of the particular source
                              2.-6S

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      Third, the commenters

 seventh circuit Court o
                                      <-
 operating practices  to
     (7th

                                                       '°tUaI
                                         asSesSment of a source -s


                                                        893 "• 2d
court had earlier

                                                     '  S'
                      -

operating constraints as well  s r     ^       *°* PhySl°al
limits.                          Federally enforceable permit
                            2-66

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  dry cleaning NESHAP,  only in how interpretation  of  the Act would
  affect future MACT  standards that may be developed  for their
  industries .
       The EPA believes that it would be unwise and inappropriate
  to resolve these complex  issues  solely in the context of the POE
  dry cleaning HESHAP.  Resolving  these issues here in the dry
  cleans, NESHAP and then applying the result to all other source

  nUMbrT'00"1* °reatS nU"erOUS Unf<™" *"*!— and impose a
  number of inequities on other sources for which NESHAP's are
  developed in the future.

  „, „,""? iSSUeS ^ beSt conside«<* »d resolved in the context
  of the General  Provisions, which will apply to all NESHAP 's.  The
  General Provisions are currently under development and are

  the^rf9  *""" iSSUM M We" M  -«• °thSr 1SSUeS  in  "*t  of
  the broad range  of sources for which NESHAP «s  will be  developed.
  lair!"1 PrOViSi0"S Wi" atte»^  *° «-ol« these issues  I  a
  manner that is reasonable  and equitable with regard  to all
  sources.
      Consistent with the Act,  the statutory definition of a  major
  source xs Deluded in the PCE  dry cleaning NESHAP to distinguish
 ma.or sources froxn area sources,  in light of the severe and
 unreasonable impacts that would be ixnposed on the dry cleaning
 industry by requiring each dry cleaner to perform a test  to
 determine  if emissions exceed 10 tons per year, the NESHAP uses
 annual  PCS, consumption (in gallons)  as a, surrogate for
 determining  sources that are likely to emit  10  tons per year or
 2.9   EMISSION LIMITS AND PERFORMANCE  TESTING
      Comment:   six  commenters  stated  that the NESHAP  should
 contaxn some  type- of, emission  limits, and performance:  testing
 Three commenters  (iv-D-24, IV-D-26,, and IV-D-27) believed tLre
 should be requirements for both refrigerated condensers and
 carbon adsorbers.  The other three commenters (IV-D-io, iv-D-22

at nled'T T^* ^^ ^ ^ ^f— Bandar  '
are needed only when using carbon adsorbers.
                              2-67

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     Three comment ers (IV-D-24
NESHaP should include emission
standards.  one colter
include a 5
                                       .,
                                              '
                                  re     "*
                                  recomende'S «»t the NESHAP

  uuction.  Thls commenter aroued th*<- ^>,
 control emissions and have .^T^LTT' "*
 enforoe an emission limit thrlu^   S*andard ls to establish and
 counter ventured that ^       P«forman=e testing.  The
'                             r.~ = -
                          2-68

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                       "  " "^ reqUeSted ttat the
               organic emission detectors mentioned in the propose,
  regulation  should  be further evaluated and required
  freaueT C0™enter (IV-D-22)  «""*- that although a desorption
  frequency requirement in  a standard is an important means to
  avoid breakthrough of the carbon adsorber, establishing an
  aTs7bPtable-r °UtlSt °°ncentr"ion' -<* « 100 pp.,  should
  also be considered.   This concentration level could  indicate
  problems with the  carbon adsorber,  such as reduced bed capacity
  or improper steam  stripping.                              pooi^y
   .    EMEOMS:  AS discussed in the proposal  preamble,  the cost
  of requiring an owner or operator to undertake a fulllfiedged
  balTr:: '"* t0 ^^^ «•*"«« .«* emission limits
  based on the use of refrigerated condensers or existing  carbon
  adsorbers would be  expensive  (S3,000 to $5,ooo,,  especially

       r
                              •                               ,
              The additional  cost of such a performance test

 thecchld CrSata a Si9nlfi°ant ***«* ^ 1*»t doublin,
 the cost that the standard would impose.

 that ma" e°°n°^C a"alySiS C°ndU°ted Pri« *» P-POsal indicated
 that many operators would likely experience difficulty in
 obtaining capital to purchase emission control equipment.  To
 preclude, unreasonable economic impacts,  the HESHAP does not
 require vent controls on existing sources with annual PCE
 d-dm                                             .
 dry to-dry machines or 200 gallons per year for sources with

 a full flirf E T"3-   ImP°Sing a*'lti°-1 ~f * requiring
 sianii    ?!   Perf°raan0e tast to Determine compliance would ad!
 Significantly to the economic  impact of the NESHAP  and  would
 resuit in  raising these- low solvent consumption  exemption levels
 for  existing sources and decrease  the  emission reductions
 achieved by  the NESHAP.  Consequently,  imposing  such a
 requirement  on dry cleaning facilities was considered
 unreasonable.
     The concerns of the commenter regarding poor operation and
maintenance of equipment, however,  are well founded.  There is?
                              2-69

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 recovered PCE. This
           —-
                  result
                                          °f
     or oerato    !T     addlt""' the NESHaP requires the
     NESHAP. „ the
temperature of the exhaust
                                  Chines, the
=•===—=

                                ,
                   2-70

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desorption, and the date and PCE concentrations measured using
colorimetric detector tubes.
     Finally, the NESHAP requires that copies of the equipment
manufacturer's specifications be retained on site.  All of the
above requirements will ensure proper operation and maintenance
of equipment and will also ensure this equipment achieves the
emission control performance it is capable of achieving.
     One commenter suggested that a State enforcement agency
could purchase an instrument to measure the emissions (such as a
portable photoionization instrument, which the commenter
estimated would cost about $5,000) and undertake a performance
test on behalf of the dry cleaner.  The costs would be recovered
through a permit fee imposed on the dry cleaner.  Presumably, the'
State would not attempt to make a profit from this service, but
would recover the full costs of this service from the permit fee.
Also, presumably the State would employ professionally trained
personnel to undertake this test as well as impose the same
quality assurance or quality control procedures as a reputable
emission testing contractor employs to ensure the results' of the
testing are accurate.
     In such a situation, the only difference in costs"to the dry
cleaning facility, whether the State performed the testing or a
contractor performed the testing, would be the profit factored
into the-contractor's service.  Although this might lower the
costs of testing by some degree, the cost imposed on the dry
cleaner would still be substantial and, in the Administrator's
judgment, unreasonable.  On the other hand, if a State wishes to
require performance testing the NESHAP does not preclude this
approach;
2.10  SELECTION OF EQUIPMENT AND WORK PRACTICE SPECIFICATIONS
2.10.1  operator Training Course
     Comment:  Four commenters (IV-D-10, IV-D-25, IV-D-27,
IV-D-28) stated that there is a need to specify and require dry
cleaning operator training and certification.  One commenter
(IV-D-10) pointed out that many dry cleaning facility operators
are not properly trained to operate and maintain control

                               2-71

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 equipment,  often resulting in excessive process and fugitive PCE
 emissions.
      One commenter (IV-D-28)  remarked that several States have
 found that,  even with adequate control devices, many dry cleaners
 are still out of compliance with their regulations because of
 poor work practice procedures.  This commenter suggested that an
 operator training course be developed by the EPA and then
 implemented through the State permit programs.  This commenter
 added that the State permit fees collected under Title V could be
 used to help subsidize the cost of the operator training or
 certification.  This commenter believed that such a training
 program would significantly improve work practice procedures.
      One commenter (IV-D-27)  noted that to reduce PCE emissions
 attributable to leaks from dry cleaning equipment due to improper
 maintenance  and repair,  the proposed NESHAP requirements for
 self-inspection and good housekeeping procedures might have a
 chance of success if certification or a training program were
 started to upgrade the performance level and knowledge of both
.plant owner  or operator and repair mechanics.   The commenter
 suggested that a training or  certification program be conducted
 through the  various existing  dry cleaner associations at minimal
 costs to the participants.
      The commenter argued that unless the operator is
 periodically tested, to maintain, certification,  there is a good
 chance that  equipment will not be properly maintained.   As an
 illustration,  the commenter cited the case of  a no-vent
 refrigerated condenser controlled dry-to-dry machine where
 exhaust levels at the loading door exceeded 800 ppm,  and the
 refrigerated condenser was  found, to; be not,operating properly.
      Another commenter (IV-D-25)  suggested, that vendors of dry
 cleaning equipment could be required to train  dry cleaners in
 their correct operation.   This  commenter added that  multi-lingual
 instruction  should be provided  where necessary.   The commenter
 recommended  that new  equipment  could be sold with service
 contracts to ensure that machines  are properly maintained.
                               2-72

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      Response;   Operator training is provided by vendors and
 distributors.   All provide training manuals with their equipment.
 In addition,  all of the distributors provide some type of on-site
 operator training and are in close contact with owners during the
 first weeks after installation of their equipment.   Some also
 offer follow-up or "refresher" training courses,  and all provide
 telephone numbers for owners to contact them with questions or
 problems.   Operator training,  therefore,  is already provided by
 both vendors  and distributors of dry cleaning equipment,  and it
 would be inappropriate and unnecessary to require additional
 training.
      Once an  owner or operator has been trained in the proper
 operation of  the dry cleaning equipment,  it is in his or her best
 interest to train the employees and ensure they are also
 operating the equipment properly.   Proper operation has an
 immediate payback in terms of the cost savings gained through
 solvent  recovery.
 2.10.2   Enforceability
      Comment;   Two commenters  (IV-D-22,  IV^D-28)  questioned the
 wording  of section 63.322(h)  of the proposal,  which gave
 requirements for the period of time in which repair parts needed
 to be-installed after their receipt.   One commenter (IV-D-28)
 stated that section 63.322(h)  of the proposal NESHAP would be
 difficult, to enforce because of the: wording, "within a-reasonable
 period of  time  after receipt."   This commenter suggested  that it
 would be helpful to the agency responsible for enforcement and to
 the dry cleaner if the  regulation  specified what  is  expected  for
 a reasonable amount of  time.   This  commenter recommended  that the
 section be  written to specify, a. specific  time allowed for
 repairs.
      The other  commenter  (IV-D-22)  stated  that  section  63.322(h)
 requires the. immediate  repair of, a  leak,  the  purchase of  repair
parts within 3 working  days, and the installation of  repair parts
within a reasonable period of time.  If the  EPA believes  the
 facility should  be  allowed to operate while repair equipment  is
on order, the commenter suggested that a  "delay of repair"

                               2-73

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 provision be included along with appropriate recordkeeping and
 possibly reporting of the "delay of repair."
      Response;   The EPA agrees with the commenter that the NESHAP
 needs to be specific and not ambiguous.   In addition,  adding
 specific time periods into, the regulation will make it easier for
 dry cleaning owners or operators to achieve compliance with the
 standards as well as for States and the EPA to enforce the
 standards.   For these reasons,  the phrase in section 63.322(h)  of
 the proposal NESHAP,  which reads "within a reasonable period of
 time after receipt," has been changed in the final rule to read
 "within  5 working days after receipt."  This amount of time
 should be sufficient for a dry cleaning owner or  operator  to
 install  a replacement part that has arrived for the machine.
      During development of the standard,  consideration was given
 to  a requirement that a dry cleaning machine be completely shut
 down until  repairs are completed.   However,  this  approach  was
 rejected in favor of specifying a limited period  of time in which
 repairs  must be made.   Emissions from individual,  specific leaks
 are likely  to be small.   In comparison,  the lost  revenues  of  not
 permitting  the  dry cleaner to clean clothes in the interim until
 the repair  is made would be large,  and is considered
 unreasonable.
      Comment:   One commenter (IV-D-28) expressed  concern that
 section  63.322(i)  of  the proposal  regulation, would be  difficult
 to  enforce  because of  the wording  "which  are  impervious to the
 solvent  and chemical reaction of the  perchloroethylene."   The
 commenter suggested that the regulation specify which  materials
 are  impervious  to  the  solvent and  chemical  reaction  of PCE so
 that  both the enforcer  and the-dry  cleaner  know what; is
 acceptable.  The commenter also  recommended changing the phrase
 "tightly sealed containers"  to "containers  that allow  no vapor
 loss," because  it would be easier to  enforce.
     Response;  As  the  commenter pointed  out,  it is  important to
clarify the requirements  of  the proposal  regulation  so that it
will be easier to enforce.   It is also important to  clarify the
requirements of the regulation so that it will be easier for  dry

                               2-74

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 cleaning  owners  and operators  to  understand.   The  commenter
 suggested including a  list  in  the regulation  of  all  of  the
 materials that are  impervious  to  the  solvent  and chemical
 reaction  of perchloroethylene; however,  such  a list  would be
 cumbersome and might be  overly restrictive.   Instead, the phrase
 that reads "which are  impervious  to the  solvent  and  chemical
 reaction  of perchloroethylene" has been  changed  in the  final rule
 to read as follows:
     All  perchloroethylene  and wastes that contain
     perchloroethylene shall be stored in solvent  tanks or
     solvent containers  with no perceptible leaks.
     Comment;  One  commenter (IV-D-28) noted  that
 section 63.322 (j) of .the proposal regulation,  which  gave
 requirements for the period of time that the  door  of the dry
 cleaning  machine remains open, would  be  hard  to  enforce because
 of the wording:  "minimize  the time the  door  of  the  dry cleaning
 machine remains open."   The commenter recommended  rewording this
 provision to be more specific:  "the  door shall  be shut
 immediately after transferring clothes and shall remain closed at
 all other times."
                       ,j
     Response;  The  EPA  agrees that this provision as proposed
 would be  difficult to  enforce.  Therefore, as.the  commenter
 suggested, the wording of the regulation which reads, "minimize
 the time  the door of the dry cleaning machine  remains open" is
 being changed in the final  rule to read as follows:
     The  door of each dry cleaning machine shall be  closed,
     immediately after transferring articles to  or from the
     machine,  and shall  remain closed at all other times.
     Comment;   One commenter (IV-D-28) noted that
 section 63.322(k) of the proposal regulation would be hard to
 enforce because, of the wording "clean lint traps frequently."
The commenter stated.that the word "frequently"  should  be
replaced with a more specific time.  The commenter suggested that
the regulation should specify that the owner or operator shall be
 in compliance with the manufacturers'  specifications regarding
the cleaning of lint traps.

                               2-75

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      Response;   In an effort to  make  the  final  rule more
 effective  and easier to  follow,  the EPA is  combining several  of
 the  equipment operating  requirements  previously listed in
 section  63.322  of  the proposal regulation into  a single
 requirement:                              r-_ .
      Each  dry cleaning system shall be  operated and maintained
      according  to  the manufacturer's  specifications and
      recommendations.
      This  requirement would  also apply  to the operation and
 maintenance of  the refrigerated  condensers  and  carbon adsorbers
 because  they are listed  as part  of the  ancillary equipment of the
 dry  cleaning system.   By doing this,  the  list of individual
 requirements given in the regulation  will be greatly reduced.
 Further, the requirement given in section 63.322(k)  of the
 proposal specifying how  frequently lint traps must  be cleaned is
 no longer  needed because the frequency  of this  activity will be
 determined by the  manufacturer's specifications  and
 recommendations.
      Comment:  One commenter (IV-D-25)  stated that  the EPA's
 definition of no "perceptible leaks"  needs  to be  tightened.  This
 commenter  thought  that a visual  inspection  is not sufficient to
 detect leaking components.   The  commenter requested that the EPA
 require  the use  of monitoring devices for periodic  emissions
 testing.
     Response;   Leaks  can be detected by  visual,  olfactory,
 tactile, or monitoring instrument methods.  Due to  the high cost
 associated with monitoring equipment,  the EPA feels  that  it is
unreasonable to require  the  use  of monitoring instruments to
detect leaks.
 2.10.3  Carbon Adsorber Requirements
     Comment;  Two  commenters (IV-D-10,  IV-D-14,  IV-D-22)
questioned the desorption requirements given in the proposed
regulation.
     One commenter  (IV-D-10)  agreed with the desorption pressure
specifications for  carbon adsorbers required in
section 63.322(c)(l) and (2)  of the proposal NESHAP, if the

                              2-76

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 carbon adsorbers are full size.  However, this commenter believed
 that smaller carbon adsorbers could be steam stripped at a lower
 pressure such as 5 pounds per square inch (psi)  instead of the
 required 170 kilopascals (Kpa)  (or 25 psi).
      The second commenter (IV-D-14)  noted that the steam pressure
 proposed in section 63.322(c)(2)  of the proposal is approximately
 double the pressure recommended by current manufacturers of
 carbon adsorbers.   The commenter argued that this proposed
 pressure level is  not appropriate and may exceed certification
 levels for the adsorber as a pressure vessel.   The commenter
 further argued that this proposed level would produce twice the
 amount of separator water,  which would need  to be sent to POTW's,
 than is generated  if operating at a pressure of 85 Kpa.
      The third commenter (IV-D-22)  questioned whether the
 desorption frequency given in section 63.322(c)(l)  of the
 proposal applies only to carbon adsorbers on dry-to-dry machines
 but not to carbon  adsorbers on transfer machines.   The commenter
 added that the basis for the given desorption frequency is not
.clearly defined in the background documents.   This commenter
 stated that the basis for the desorption frequency appears in
 EPA-340/1-80-007.
      This commenter suggested that any desorption frequency
 standards be stated as an equation or mathematical expression,
 such, as • the- maximum- number of  dryer  cycles  (N)  before: desorption
 should equal the weight  of adsorber  carbon,  in pounds (W),  times
 3.3  and divided by the dryer capacity,  in pounds (C),  or
 N = 3.3 W/C.
      Response;   In the final rule, new and uncontrolled dry
 cleaning machines  will be required to install  refrigerated
 condensers.   Therefore,  only existing dry cleaning machines with
 existing carbon adsorbers will  be allowed to use carbon adsorbers
 to  meet the requirements of the final rule.
      The EPA agrees with the commenter that exceeding
 certification levels for an existing carbon adsorber  as a
 pressure vessel is not desired, and  the regulation  does not
 intend for the  dry cleaner  to operate an existing  carbon adsorber

                               2-77

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in such a manner.  In drafting the carbon adsorber operational
requirements that appeared in the proposal, information at that
time indicated that one basic size and type of carbon adsorber
was being used by dry cleaning owners and operators to control
PCE emissions.  The operating requirements given in the proposal
were appropriate for operating this specific type of carbon
adsorber.  However, since that time, it has become apparent that
other types of carbon adsorbers have been sold for use on dry
cleaning machines.  Some of these carbon adsorbers have their own
specific operational requirements so that the requirements set
out in the proposal may not be applicable.  Operation manuals,
operational specifications, and desorption schedules are provided
by the manufacturer or vendor which specify the appropriate
desorption steam pressure requirements for operating an
individual carbon adsorber.  Because this information is readily
available, the owner or operator of an existing carbon adsorber
must obtain and follow these specifications in operating the
carbon adsorber.
     The final NESHAP deletes all specific operational
requirements and instead requires that each existing carbon
adsorber be operated and maintained according to the
manufacturer's specifications and recommendations.  in addition,
the dry cleaner must measure and record the concentration of PCE
in the exhaust from an existing carbon, absorber on a weekly
basis.  This information will aid the dry cleaner in determining
if breakthrough has occurred.  The manufacturer's specifications
as well as the log containing PCE concentration measurements must
be retained on site for 5 years.
     Comment:.  One„commenter (IV.-D-10V suggested that
specifications be included in;the regulation regarding proper
maintenance of carbon adsorber prefilters.  The commenter
explained that if this prefilter is not properly maintained, and
the polyurethane foam filter type is replaced with an inferior
filter media, then the adsorption efficiency of the carbon
adsorber would be adversely affected by lint accumulation.
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      Response;   As discussed above,  manufacturers and vendors
 provide specifications for effective operation of existing .carbon
 adsorbers,  including requirements for proper maintenance of
 carbon adsorber prefilters.   For this reason,  the final NESHAP
 requires that each dry cleaning system including ancillary
 equipment shall be operated and maintained according to the
 manufacturers'  specifications and recommendations.
      Comment;   One commenter (IV-D-14)  thought that,  in some
 cases,  the interval required in section 63.322(c)  of the proposal
 regulation for  desorbing a.carbon adsorber could be  too long,  and
 the  carbon bed,  therefore,  could become saturated before
 desorption occurs.
      The commenter noted that this situation could occur from
 either greater  than normal  amounts of PCE  vapor flowing to the
 adsorber during the drying  cycle or  from reduction of adsorber
 capacity with age.   The commenter suggested  that an  optimal
 desorption  interval be determined based on individual adsorber
 performance for a  given machine.
      The commenter recommended that  the first  desorption after a
 permit  is granted  could use  the 3  kilogram (kg)  clothes per  kg of
 carbon  guidance  as  outlined  in the proposed  regulation.   However,
 if this desorption frequency returns more  PCE  than 90 percent  of
 the rated PCE capacity of the adsorber,  the  commenter suggested
 that  the dry cleaner desorb  more  frequently  until  a desorption
 return  is reached  that is less than  90  percent of the rated
 capacity of the  adsorber.
      The commenter  explained that  the period between  this  optimal
 desorption  frequency could then be correlated  with the  amount  of
 clothes: cleaned.  In this way,  the dry  cleaner could; adhere  to
 the desorption schedule  by monitoring the  amount of clothes
 cleaned.  The commenter  also  suggested  that  a  periodic  test
 should  be conducted  to confirm that  the  selected desorption
 interval  is still appropriate.  The  commenter  suggested amending
the recordkeeping requirement  in section 63.325(a)(3) of the
proposal to require  that ar record be made of the amount of PCE
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 returned from each desorption so that adherence to the optimal
 desorption schedule can be verified.
      Response;   As stated elsewhere,  only existing dry cleaning
 machines with existing carbon adsorbers will be allowed to use
 carbon adsorbers to meet the requirements of the final NESHAP.
 To control PCE emissions,  existing carbon adsorbers must be
 properly operated,  particularly in terms of desorption frequency.
 By following the manufacturers'  specifications and
 recommendations for a dry cleaning system and ancillary
 equipment,  the  dry cleaner owner or operator should be able to
 operate the existing carbon adsorber  effectively.   Because there
 are several different types of carbon adsorbers being used to
 control PCE emissions from dry cleaning machines and each one has
 its own specific operational characteristics,  the final NESHAP
 requires that each  existing carbon adsorber shall be operated and
 maintained  according to the manufacturer's specifications and
 recommendations.  In addition, the dry cleaner must measure and
 record the  concentration of PCE  in the exhaust from the carbon
 absorber on a weekly basis.   This  information  would aid the dry
 cleaner in  determining if  breakthrough has occurred and the
 carbon adsorber  needs to be desorbed.
     Comment;  One  commenter (IV-D-10)  requested that  the
 regulation  specify  that all exhaust from the washer, the dryer,
 the; filter  and purification-system, the holding  tanks,  and,the
 attendant piping  and valves must be routed through  the  carbon
 adsorber or  a solvent reclamation  tank.
     Response;  The  EPA agrees with the  commenter that  the  term
 "entire exhaust," which is  required to  be  routed through a  carbon
 adsorber, refrigerated  condenser,  or equally effective  control
 device, in section  63.322(b) of the proposal may be confusing.
The term "entire exhaust" has been  deleted  from the NESHAP.  The
emissions from ancillary equipment  are considered "equipment
leaks" which are addressed elsewhere in the final regulation.
2.10.4  Refrigerated Condenser Requirements
     Comment;  One commenter  (IV-D-12) requested a clarification
in section E of the preamble that reads, "these operating

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 specifications  include maintaining  the  temperature  of  the  outlet
 side  of  the refrigerated  condenser  at less  than  or  equal to
 4.4 °C  (40 °F)."  The commenter  stated  that the  word
 "maintaining" does  not describe  the actual  refrigerated condenser
 air temperature cycle.
   .   The commenter  thought that  the preamble description needed
 to be restated  to include an outlet temperature  level  of 40 °F at
 the end  of the  drying or  cool down  cycle.   The commenter stressed
 that  the 95 percent efficiency for  dry-to-dry vented machines
 depends  upon maintaining  the refrigerated condenser outlet
 temperature below 40 °F at the end  of the drvina or cool down
 cycle.   The commenter attached a report with test data to support
 this  claim.
      Another commenter (IV-D-14) recommended that the  beginning
 of section 63.322(d)(l) of the proposal be  revised  to  read:
      (1) No exhaust gases shall  be  vented to the atmosphere
      or  the door opened on a refrigerated machine until the
      air-vapor  stream temperature.  . .  .
 The cqmmenter stated that the proposed  wording could have been
 read  literally  to prevent the drying cycle  on a  dry-to-dry
 refrigerated machine from ever beginning because gases could not
 be "circulating through a ventless  machine" until the  proper
 temperature was reached.   The commenter's suggested wording would
 prevent  the door from being opened  on a dry-to-dry refrigerated
machine  until the proper temperature is reached.
     Response;  The EPA agrees that the word "maintaining," which
was used in the proposal preamble, could be misinterpreted to
 inaccurately describe the actual refrigerated condenser air-vapor
 stream temperature..cycle.   In addition,  the EPA  agrees that
 section  63.322(d)(2) as proposed would have prevented air from
circulating through a dry-to-dry machine when the air-vapor
stream temperature was not cooled sufficiently.   This was not the
 intent of the regulation.   Therefore, the final regulation
requires the owner or operator to.measure the temperature on the
outlet side of the refrigerated condenser.   For refrigerated
condensers used with transfer machine system washers,  the

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 temperature difference between the inlet and outlet
 air-perchloroethylene gas-vapor stream must be measured.  For
 refrigerated condensers used with transfer machine system dryers
 or reclaimers, or dry-to-dry machines, the temperature of the
 exhaust gas stream must be measured.  Measurements should be
 taken before the door on the dry cleaning machine is opened.  The
 temperature shall be less than or equal to 7.2 °c (45 OF).
      The temperature requirement of 4.4 °C (40 °F) included in
 the proposed NESHAP was an error.   This requirement was intended
 to be 7.2 oc (45 °F).   Consequently,  the temperature requirement
 is 7.2 oc (45 OF)  in the final rule.   The measured temperature
 must be recorded on a weekly basis in a log to be maintained on
 site for five years.
      In addition,  the final NESHAP contains two other
 requirements for ensuring the proper operation of refrigerated
 condensers.   The first requirement is that the dry cleaning
 system (including ancillary equipment such as  the refrigerated
 condenser)  shall be operated and maintained according to the
 manufacturer's specifications and  recommendations.   The second
 requirement  is that there shall be no venting  of  the
 air-perchloroethylene  gas-vapor stream to  the  atmosphere during
 any  time the dry cleaning machine  drum is  rotating.   These three
 requirements help  ensure  that the  dry cleaning machine  and the
 refrigerated condenser are being operated  so as,to minimize  PCE
 emissions.
     Comment;   One  commenter  (IV-D-12)  objected to the  wording of
 section  63.322(a) of the proposal.  This commenter submitted a
 sketch of a  dry-to-dry machine retrofitted with a refrigerated
 vapor condenser  to  illustrate that an  air tight diverter valve
 must be mounted  externally between the refrigerated; condenser  and
 the dry-to-dry machine.
     The commenter explained that during the drying or  cool down
portion of the machine cycle, the diverter valve is sealed to the
atmosphere, directing PCE-laden vapor to the refrigerated
condenser.  The commenter explained that when the drying cycle  is
completed and the vented dry-to-dry door is opened, the diverter

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valve damper  automatically  opens to the  atmosphere  and,  at  the
same instant,  seals  off the vapor  condenser  freezing  coil.   This
event allows  the  air to flow  from  the room into the dry  cleaning
machine over  the  cleaned clothes and directly  into  the
atmosphere.
     The commenter stated that  if  warmer, unsaturated room  air  is
exhausted through the refrigerated condenser as allowed  in  the
proposed rule, the air flow would  pass over  the frozen PCE/water
laden coils of the refrigerated condenser and  would result  in
uncontrolled  PCE  emissions.
    , Response;  The  EPA agrees  with the  commenter that drawing
unsaturated room  air over the coils of a refrigerated condenser
would lower the control efficiency of the refrigerated condenser.
For this reason,  the final  rule requires that  a diverter valve  be
installed and operated on each  dry-to-dry machine,  transfer
dryer, or reclaimer  that draws  room air  into the machine when the
door is opened.   As  the commenter  pointed out, the  diverter valve
prevents room air from being drawn over  the refrigerated
condenser coils.  Refrigerated  condensers installed on transfer
system•washers, however, are configured  to be  single  pass rather
than multiple pass.  In this instance, room air is  drawn in
through the machine  door and routed directly over the
refrigerated coil and vented out.  The use of  a diverter valve
could not be used with this equipment configuration.  Therefore,
use of a diverter valve is not  required  on transfer machine
system washers.
2.10.5  Purchase Orders
     Comment;  One commenter (IV-D-14) reported that  dry
cleaners,  particularly smaller  dry cleaners',  frequently do  not
use written purchase orders when ordering replacement parts.  The
commenter noted that, instead,  they typically telephone an  order
to their distributors.   For this reason,  the commenter
recommended that written purchase orders not be required in the
repair provisions of section 63.322(h) or the recordkeeping
provisions of section 63.325(a)(2)  of the proposal.   The
commenter suggested that the word "purchase"  be deleted from

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 sections 63.322(h)  and 63.325(a)  and the words "verbal or
 written" be inserted in section 63.322(h)  of the proposal.
      Response;   The EPA agrees with commenter that the owner or
 operator of a dry cleaning facility may not always use written
 purchase orders  when obtaining replacement parts for a dry
 cleaning machine.   For this reason,  it  would be inappropriate to
 require  that dry cleaning owners or operators always use written
 purchase orders.   The commenter noted that dry cleaning owners or
 operators typically telephone in orders for parts to their
 distributors.  The EPA agrees that,  if  this is the case,  a
 written  record of their telephone conversation would suffice
 instead  of  a purchase order.   The wording of this provision has
 been  revised as  follows in  the final NESHAP:
      If  repair parts must be ordered, either a written or
      verbal order for those parts shall be initiated within
      2 working days of detecting such a leak.
 2-10.6   Saturated Lint and  Cartridge Filter
      Comment•  one  commenter (IV-D-14)  recommended that
 "saturated  lint  from the lint basket" be deleted from
 section  63.322(g)(10)  of the proposal because it is not a
 component of  a dry  cleaning machine.
      Response;  The"EPA agrees with  the commenter that the
 saturated lint from the lint basket  is  not a  component of a dry
 cleaning  machine.   Therefore,  this item has been deleted  from the
 list  of dry cleaning system components  that must be inspected for
 perceptible leaks.
      Commenti  One  commenter  (IV-D-14)  suggested that
 section 63.322(g)(11)  of  the  proposal be revised to read
 "cartridge  filter housings," because  a cartridge  filter is not a
 component of a dry  cleaning machine.,
     Response;  The  EPA agrees with  the  commenter that the
 cartridge filter housing  is the component  of the dry cleaning
machine that could be  a potential source of leaks rather  than the
cartridge filter.  For  this reason,  the component listed  in
section 63.322(g)(11)  of  the proposal has  been changed to
cartridge filter housings in the final NESHAP.

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 2.10.7  Compliance Timetable
      Comment!   One commenter (IV-D-25)  requested that the EPA
 accelerate the compliance timetable to 18 months for all sources.
 The commenter  cited a trade association as saying they can comply
 more quickly.   The commenter added that a year ago,  the EPA had
 stated that dry cleaners would be given 18 months to comply
 because vendors had reported that they could supply  the necessary
 equipment within 1 year.
      Response:   As the commenter pointed out,  at proposal vendors
 did say that they could supply the necessary control equipment
 within 1 year.   Since proposal,  however,  the low solvent
 consumption exemption levels have been lowered to include a
 greater number of dry cleaning facilities that must  comply with
 the final rule.   In addition,  all new  and existing uncontrolled
 dry cleaning machines are required to  install  refrigerated
 condensers,  rather than given the option of refrigerated
 condensers or  carbon adsorbers.   Based  on the  increased demand
 anticipated for  refrigerated condensers,  vendors may no longer be
 able to supply, control devices to all  facilities requesting them
 within 18  months.   For this  reason,  the compliance date for all
 existing facilities has been shifted to 36  months.
 2.11  TEST METHODS AND MONITORING
      Commentt  One commenter (IV-D-28)  stated  that
 section 63.322(f)  of. the  proposal NESHAP  should  be more specific
 by  specifying that the owner or  operator  shall be  in compliance
with the manufacturer's specifications  regarding how frequently
to  drain or  dispose of cartridge  filters.
      Response:   The EPA believes  that 24 hours is  a  reasonable
time  to require for draining, cartridge,  filters.  For, this reason,
the  proposed draining  time has been retained in  the  final rule.
      Comment;  One  commenter  (IV-D-28)  noted that  section 63.324
of the proposal does not  specify  at what reading a portable
halogenated-hydrocarbon detector  triggers compliance.  The
commenter recommended  that the NESHAP specify a  specific
concentration increment above the background level that would
represent a significant leak.  The commenter further  suggested

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 that section 63.322 of the proposal require dry cleaners to use a
 portable detector at some specific time frequency (such as every
 3 months or every 6 months)  to detect those leaks that are not
 visually apparent.
      Response;   Leaks on dry cleaning machines can be detected
 through-visual  or olfactory inspection.   The use of a portable
 halogenated detector is not required and,  therefore,  there is no
 reason to establish a specific leak detection level or a
 frequency requirement.
       Comment:   One commenter (IV-D-14)  urged that the definition
 of perceptible  leak be revised to specifically state that use of
 a halogenated hydrocarbon detector is permitted but not required.
 The commenter thought that the definition  of perceptible leak
 read together with  the inspection and repair requirements in
 paragraphs (g)  and  (h)  of section 63.322 of the proposal seemed
 to nullify the  option of inspecting leaks  either visually or with
 a detector.
      Response;   Visual  and olfactory detection are very effective
 for locating leaks,  therefore,  the use of  a halogenated
 hydrocarbon detector was not required in the proposal.   Thus,
 reference to a  halogenated hydrocarbon detector in the  definition
 of perceptible  leak  has been deleted.
 2.12  WORDING OF THE REGULATION
 2.12.1  References to Other  Subparts
      Comment:   One commenter (IV-D-28) stated that
 section 63.322(1) of the proposal  regulation refers to
 63.9(b)(2)(vi),  which is located  in  Subpart A.   The commenter
 suggested that  this  section  be  reworded  to  read "63.9(b)(2)(vi)
 of  Subpart A" to make it clearer that  this: section is not  located
 in  Subpart M.   The commenter suggested the  same rewording  be
 added in  section 63.325(c) of the  proposal  regulation to clarify
 that  63.9(h), is  found in Subpart A.
     Response;   The  EPA  agrees with the  commenter  that
 referencing  section  numbers  that are found  in other subparts
without mentioning that  these sections are  found in other
 subparts may be  confusing, especially  for dry cleaning owners or

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 operators  that may not be familiar with the organization of the
 Code  of  Federal Regulations.   For this reason,  every time a
 citation from another subpart is given,  the NESHAP now notes what
 subpart  contains that citation.
 2.12.2   Clarifications
      Comment;   One commenter  (IV-D-28)  pointed  out that
 section  63.325(d)(2)  of the proposal,  which refers to "830 liters
 per year (200  gallons per year)  perchloroethylene" should read
 (220  gallons per year)  perchloroethylene.
      Response;   The conversion from liters  to gallons should have
 read  220 gallons per  year.
      Comment;   Two commenters (IV-D-14,  IV-D-28)  noted that
 section  63.325(c)  in  the proposal,  which refers to "the
 compliance  dates given in section 63.322(c)" should read "the
 compliance  dates given in section 63.322(e)."
      Response;   The citation  to  compliance  dates  has been
 corrected in the final NESHAP.
 2.12.3   English Units
      Commenti   Two commenters (IV-D-10,  IV-D-14)  requested that
 English  units,  which  are more familiar to dry cleaners,  be
 included in the NESHAP for units  of pressure and  air flow.   One
 commenter (IV-D-10) noted that 170  Kpa equals approximately
 25 pounds per  square  inch (psi) and the  air flow  capacity of
 0.3 cubic meters per  second equals  approximately  630  cubic feet
per minute  (cfm).
     Response;  The EPA  agrees with the  commenter  that  owners  and
operators of dry cleaning facilities would be more familiar  with
•English units than with  metric units because these are  the common
types of measurements  that dry cleaners  use.  Because  it  is
 important that  the NESHAP be understandable and easy to read  for
dry cleaner owners or  operators,  both English and  metric  units
have been included.
     Comment;  One commenter  (IV-D-12)  questioned  the English
conversion of 0.3 cubic meters per  second (m3/sec)  (0.1 cubic
foot per second  [ft3/secs]) air flow through the carbon adsorber.
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      Response;   The English conversion for an air flow of
 0.3 m3/sec through the carbon adsorber should be lb ft3/sec.
 2.12.4  Definitions
      comment;   one commenter (IV-D-14)  recommended several
 changes be made in the definition section of the NESHAP.   The
 commenter suggested the following revised definitions to  five
 terms to remove any implication that filter elements can  be
 regenerated:
      Cartridge  filter means a discrete solvent filter unit,
      inserted in a multi-unit housing,  which must be replaced
      periodically.
      Muck cooker means a device for  heating diatomaceous
      earth filter material  to drive  off perchloroethylene
      vapors for reclaiming.
      Stills are defined as  devices used to volatilize and
      recover perchloroethylene from  contaminated solvent.
      Wet waste  material means the filter  muck from a
      diatomaceous earth filter or the residue from a still.
 The  commenter suggested replacing the definition for "regenerable
 filter material"  with the following:
      Filter muck  means the  residue from a filter using loose
      diatomaceous earth which must be replaced periodically.
      Response:  In  general, the EPA  agrees  with  the  commenter's
 suggested changes to  the definitions and  has  incorporated  them
 into  the final -NESHAP,  except for the reference  to "multi-unit
housing"  in the recommended definition  of cartridge  filter.
Because  some dry  cleaners may not place their  cartridge filter in
a "multi-unit housing,"  this  portion of the recommended
definition,has not  been  incorporated into, the  final.  NESHAP.
      Comment:  One  commenter  (IV-D-14)  suggested  inserting the
word  "system" after the word  "transfer  machine"  in the definition
of dry cleaning system to make the use  of the phrase  "transfer
machine system" consistent throughout the NESHAP.
     Response;   The EPA agrees with the commenter that it would
be clearer  if the phrase transfer machine system  is-used
throughout the NESHAP to describe both the transfer washer and

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 the transfer dryer.  For this reason,  the word "system" has been
 inserted after the word "transfer machine" in the definition  of
 dry cleaning system to make the use of the phrase "transfer
 machine system" consistent throughout the final NESHAP.
      Comment;   One commenter (IV-D-22)  requested that the word
 "existing"  be defined to clarify which equipment is affected.
 The commenter noted that this term is  used in paragraphs (b)
 and (c)  of  section 63.320 and paragraphs (b)(2)  and (e) of
 section 63.322 of the proposal NESHAP.
      Response;  The term "existing" means any dry cleaning
 machine that was built prior to the date of proposal.   To clarify
 the meaning of this term,  a specific definition fpr "existing"
 has been included in the definition section of the final NESHAP.
      Comment;   One commenter (IV-D-22)  requested that definitions
 be  given in the NESHAP to distinguish  between three terms used in
 section 63.322 of the proposal:  "ventless machine," "vented
 machine," and  "no-vent machine."
      Response;   Although different descriptions  (ventless,
 vented,  and no-vent)  may have been used to describe the types  of
 dry-to-dry  machines in the proposed NESHAP, these descriptions
 are not  necessary.   Because requirements set  out in the NESHAP
 are the  same for all dry-to-dry machines regardless of  whether
 they are vented or not,  there is  no need to differentiate between
 these terms.   There are no common definitions  of these  terms
 throughout  the  dry cleaning industry.   They mean something
 slightly different to different dry cleaners.  Therefore, using
 the  terms in the  rule would be confusing to dry  cleaners.   For
 this  reason, all  mention of these  terms  was deleted from  the
 final NESHAP.
 2.12.5  Applicability
      Comment;   one  commenter  (IV-D-10)   suggested revising
 section  63.320(a)  of  the proposal  to delete "dry cleaning
dryers," because  dryers  are a part of a transfer machine  system,
and to replace  the word  "facilities" with the word  "plants."
     Response;  The EPA  agrees with the commenter that  it is
redundant to include the phrase "dry cleaning dryers" in

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 section 63.320(a)  of the proposal because a transfer machine
 system as defined in section 63.321 includes both a transfer
 washer and a transfer dryer.   Therefore,  the phrase "dry cleaning
 dryers" has been deleted from section 63.320 in the final NESHAP.
      The term "facility" was selected over the term "plant"  in
 drafting the NESHAP because the word "plant" connotes a larger,
 industrial sized dry cleaning establishment.  Because the
 majority of  dry  cleaning establishments are small,  family
 operated businesses,  it  is  more appropriate to call them
 facilities.
 2.12.6  Standards
      Comment;  One commenter  (IV-D-14) suggested that the word
 "liquid"  be  inserted in  front of the word "perchloroethylene"
 each  time it appears in  paragraphs  (i) and (k)  of section 63.322
 of the proposal.   The commenter believed  that this  addition  would
 make  the  storage and lint-cleaning  requirements more precise by
 specifying that  liquid PCE  and waste containing liquid PCE are to
 be stored in tightly sealed containers.   The commenter observed
 that,  otherwise, dry lint containing only trace elements  of  PCE
 would also have  to be so stored,  which would be unnecessary  and
 burdensome.
      Response;   Disposal of hazardous wastes must be conducted in
 accordance with  the Resource  Conservation and Recovery Act
 (RCRA).   If  the  total wastes  generated during the dry cleaning
 process,  including lint  and filter muck,  contain PCE in a
 sufficient quantity to qualify as a  hazardous waste  under  RCRA,
 then  that  waste must  be  stored in a  container that does not  leak.
 Because the  requirements of section  63.322 apply to  liquid PCE
 wastes as well as  to  solid waste containing, PCE,  it  is  not
 appropriate  to incorporate  the  commenter's suggestion  into the
 final NESHAP.
 2.13  EQUIVALENCY
     Comment;  Three  commenters  (IV-D-24,  IV-D-26, IV-D-30)
 expressed concern that- States were not delegated authority in  the
proposal to  implement and enforce equivalent  or more protective
 State requirements.  One commenter (IV-D-24)  stated that the EPA

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 should recognize that 22 States currently regulate PCE emissions
 from dry cleaning facilities and that these facilities will be
 required,  at a minimum,  to comply with these State regulations
 even after a NESHAP for  PCE is promulgated.   Two commenters
 (TV-D-24,  IV-D-30)  emphasized that States must retain the right
 to take appropriate actions to implement effective emission
 control strategies to protect public health within their
 jurisdictions.
      All of these commenters strongly opposed section 63.326 of
 the proposal that limits the authority for approving alternative
 control equipment and procedures proposed by individual dry
 cleaning sources to the  EPA alone.   One commenter (IV-D-24)
 believed that the EPA's  retention of this delegation of authority
 would also negatively impact the operating permit process.
      One commenter (IV-D-30)  insisted that States be allowed to
 enforce a  State standard that is different from the Federal
 standard if it  is of equivalent or greater stringency.   This
 commenter  cited section  112(1)(1)  of the amended Act,  which
 allows  the EPA  to approve a State program that  provides for
 "partial or complete"  delegation of the Administrator's
 authority.   This commenter also cited section 112(d)(7)  which
 reads:
      No  emission standard or  other  requirement  promulgated
      under this  section  shall be interpreted. construed,  or
      applied to  diminish or replace the requirements  of a
      more  stringent  emission  limitation or other applicable
      requirement established pursuant to  ...  this Act or  a
      standard issued under  State authority.   (emphasis  added
      by  commenter)
      This,  commenter  argued:that if, a  State were.not allowed to
 implement  its own standard  instead  of  the EPA's  (and  both
 standards  had.to be  implemented  simultaneously), then two
 significant problems would  occur:   (1)  it may be; physically
 impossible for sources to comply with  both standards; arid (2) it
 likely would increase the administrative and financial  burden on
sources and regulatory agencies, with  no additional public health
benefit.  The commenter mentioned that dual regulation  could
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 result in undue financial and administrative burdens on small
 businesses.   The commenter added that if a source is forced to
 comply with  two sets of incompatible requirements,  the source may
 not be able  to operate at all in a particular State.
      The commenter specifically suggested adding a  new section to
 the proposed NESHAP.   This commenter explained that this new
 section would explicitly allow a State to seek approval to
 implement and enforce 40 CFR Part 63,  Subpart M by  implementing
 and enforcing an alternative emission standard adopted by the
 State.   The  commenter explained that to receive approval from the
 Administrator,  a State would have to demonstrate that the
 alternative  emission standard would provide the same  public
 health benefit as,  or a greater benefit than,  the standard
 promulgated  pursuant to section 112(d)  of the Act.  The commenter
 added that the demonstration should include an analysis of the
 overall emission and risk reductions associated with  each
 standard,  specific  to sources in the State.
      The commenter  also suggested modifying the first sentence in
 section 63.323(a) of  the proposal to read:
      Upon written application from any person or Statef  the
      Administrator  may approve the individual  or Statewide
      use of  equipment or procedures that  have  been
      demonstrated to  his satisfaction  to  be equivalent in
      terms of reducing perchloroethylene  emissions  to the
      atmosphere,  to those prescribed for  compliance within a
      specified paragraph of  this  subpart.
      Response;   The EPA agrees with the commenters  that  States
should  be  allowed to  implement  effective  emission strategies to
protect  public health within  their  jurisdictions.   In some  cases,
States may feel  it  is  necessary to  implement more protective air:
pollution control measures than those adopted  in national
standards to control  local problems.
      In  addition, the  SPA also agrees with the commenters  that if
different types  of  specific controls were required by the dry
cleaning NESHAP  and a  State's standard, then it might be
physically impossible  to comply with both standards.  For this
reason, the NESHAP  includes provisions for determining
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equivalency that allow sources to use any means of controlling
emissions that result in an equal or greater level of emissions
reduction as that achieved through the use of the controls
required in the NESHAP.  These provisions will permit sources to
achieve compliance with both State standards and the NESHAP.  In
fact, this type of approach fosters advances in control
technology development and source reduction and other pollution
prevention alternatives as a means for achieving compliance.
     Finally, the EPA also agrees with the commenters that
provisions limiting the authority to the EPA alone for making
judgments regarding the equivalency of different equipment to
control PCE emissions with the same or better performance than
the control equipment required by the NESHAP is not warranted
because section 112(1) of the Act would allow a State to request
approval of a State's program that permits a source to seek
permission to use an alterative means of emission limitation
under section 112(h)(3), provided that the State demonstrated
that is program would be no less stringent and that certain
conditions were met.  Section 112(1) authorizes States to submit
programs to the Administrator for approval for implementing and
enforcing emission standards.  Section 112(1) also goes on to
state that such programs may provide for partial, as well as
complete, delegation of the EPA's authorities and
responsibilities.  The approval and delegation process is,
addressed in detail in the EPA's notice of proposed rulemaking:
"Approval of State Programs and Delegation of Federal
Authorities; Proposed Rules," published on May 19, 1993,
(58 FR 29296).
     As a result, the. provision limiting the authority; to judge
the equivalency of different equipment to the EPA,has been
deleted from the final standards.  Doing so, however, does not
mean that these provisions will be "automatically" delegated to
States upon application.  In addition, delegating these
provisions will not preclude the EPA from considering petitions
submitted by various equipment suppliers or vendors and making
equivalency determinations on a national level.

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      Comment:   One commenter (IV-D-14)  offered a suggestion for
 section 63.323  of the proposal,  which allows alternative
 technologies to be used in lieu  of the specified control devices.
 The commenter stated that a properly operating carbon adsorber
 exhausts approximately 25 parts  per million (ppm)  of PCE at
 600 cubic feet  per minute (cfm).   The commenter included
 calculations to show that this exhaust is  equivalent to
 3.1 pounds of PCE emissions per  day,  assuming the adsorber
 operates 8 hours per day.
      The commenter suggested that  the EPA  could specify in the
 equivalency provision that one possible method for demonstrating
 an  alternative  technology would  be to show that emissions from a
 given control device would result  in no more than 3.1 pounds  of
 PCE emissions per day.   The commenter pointed out that this
 approach would  achieve similar emissions reductions without tying
 the alternative control to a particular PCE concentration,
 exhaust  flow rate,  or total exhaust time.   The commenter believed
 that this approach could simplify  the task of those considering
 or  engaged in the manufacture of alternative control devices.
 The commenter believed that this equivalency approach could lead
 to  the design and construction of  simpler  and less  expensive
 alternative  control  technologies for  controlling  PCE emissions.
      Response:  As stated  elsewhere,  new and uncontrolled
 existing  dry cleaning machines are  required  to  install
 refrigerated condensers  to comply with  the requirements  of  the
 final NESHAP.   Existing  dry cleaning  machines with  existing
 carbon adsorbers  built prior  to promulgation will not be  required
 to replace their  carbon  adsorbers with  refrigerated  condensers,
 but; new carbon;adsorbers are  not allowed for process vent
 control..  Therefore,  potential alternative: technologies will be
 evaluated based on equivalent performance to a refrigerated
 condenser rather than a  carbon adsorber.
     With regard to carbon adsorbers, however, the EPA does not
agree with the commenter that 25 ppm  is the normal exhaust
concentration when the dry cleaning machine  is not venting to the
carbon adsorber and,  in EPA's opinion, the assumption that a

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 properly operated carbon adsorber  exhausts  at  a  constant  25  ppm
 has  not  been verified.   In any event,  because  the  performance  of
 carbon adsorbers  in  actual practice  has  been shown to  be  inferior
 to refrigerated condensers and because a refrigerated  condenser
 is configured differently from a carbon  adsorber,  the  approach
 suggested by the  commenter is  not  appropriate  for  determining
 equivalency  with  the performance of  a  refrigerated condenser.
     Requiring the same  approach for demonstrating the
 equivalency  of an alternative  technology may not be appropriate
 for  all  types of  new control technologies introduced to the
 market.   For this reason,  specific methods  for demonstrating
 equivalency  are left to  the requestor  seeking  equivalency, based
 on the specific characteristics of the control technology.
     Comment:  One commenter (IV-D-19) expected  to be  requesting
 an equivalency determination for a new control technology in the
 near future.  For this reason,  the commenter requested guidance
 in seeking equivalency under section 63.323 of the proposal.
     First,  the commenter asked what type of information should
 be included  about the control  technology.  The commenter thought
 that pertinent information would include:  a general description
 of the equipment;  a  schematic  of the equipment denoting its  size;
 cost of  the  equipment (both when added to a new  machine and  when
 a machine was retrofitted); and energy requirements of the
 system.
     Second, the  commenter asked what  was needed concerning
process  or fugitive  emission data.   The  commenter  asked what type
of data must be collected  and  over what  time period.  The
commenter wanted  to  know  if the applicant is responsible for
collecting baseline  data on the: particular- piece of equipment
prior to the control being added.  The commenter wondered if the
EPA would require monitoring data to be collected  from more than
one machine.  The commenter also questioned whether the EPA would
require the piece of equipment being used in the testing to
already be used on a commercial basis.  The commenter asked
whether the EPA or its contractor would collect  emissions data  in
addition to the data being collected by the applicant.

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     Third, the coramenter inquired about efficiency
determination.  The commenter asked how the EPA would calculate
the efficiency of the particular control technology being
considered.  The commenter also questioned that if a system
reduces both process and fugitive emissions, would the EPA
consider both reductions in its determination.
     Fourth, the commenter asked about the overall approval
process.  The commenter requested an outline of the steps and an
estimate of the time needed to undergo the equivalency approval
process.
     Response:  In answer to the commenters1 questions, it is
difficult to specify what information must be submitted without
knowing some details of the emission control technology or system
for which a determination of equivalency is requested.  In
addition, a description of this information must be broad and
general in nature to accommodate all possibilities.  It is
possible, however,  to be more specific, and the final NESHAP
specifies that the following information must be submitted:
     •    Diagrams,  as appropriate,  illustrating the emission
          control technology,  its operation and integration into
          or function with dry-to-dry machine(s)  or transfer
          machine system(s)  during each portion of the normal dry
          cleaning cycle;
     •    Information quantifying vented PCE.emissions from the
          dry-to-dry machine(s)  or transfer machine systems(s)
          during each portion of the dry cleaning cycle with and
          without the use of the candidate emission control
          technology;
     •    Information on solvent mileage achieved with and
          without the candidate emission control  technology.
          Solvent, mileage- is the, average weight of, articles
          cleaned per volume of PCE  used;
     •    Identification of  maintenance requirements and
          parameters to monitor to ensure proper  operation and
          maintenance;
     •    Explanation of why this information is  considered
          accurate and representative of both the short-term and
          long-term  performance of the candidate  emission control
          technology on the  specific dry cleaning system
          examined;
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     •    Explanation of why this information can be extrapolated
          to dry cleaning systems other than the specific
          system(s) examined;
     •    Information on the cross-media impacts (to water and
          solid waste) of the candidate emission control
          technology and demonstration that the cross-media
          impacts are less than or equal to the cross-media
          impacts of a refrigerated condenser.
2.14  MISCELLANEOUS
2.14.1  Classification of Perchloroethvlene as a Volatile Organic
        Compound
     Comment;  One commenter (IV-D-03) agreed that PCE needs to
be controlled as an air toxic.  However, the commenter believed
that including PCE as a volatile organic compound (VOC) has
created a problem.  The commenter pointed out that the EPA
published a Federal Register notice on October 24, 1983,
(48 FR 49097) proposing to add PCE to the list of exempt VOC
compounds.  The commenter stated that a final action on the PCE
photochemical reactivity issue is being withheld until the PCE
toxicity issue is resolved.
     The commenter stated that, pursuant to the definition of VOC
(which includes PCE), and the EPA and State guidelines, his air
pollution control district was required to issue emission
reduction credits (ERC's) for substantial reductions in PCE
emissions at a single source (107 tons per year).  The commenter
explained that, under the existing VOC definition, these ERC's
must be used to offset emission increases from new sources of VOC
whose photochemical reactivity is not negligible, resulting in a
net increase in ozone precursors.  The commenter argued that the
use- of: PCE, ERC's- as: offsets, exacerbates- the severe, ozone
nonattainment problem in his area because the emission increases
in reactive compounds would not be truly offset.
     The commenter recommended that the EPA finalize its proposal
to list PCE as an exempt VOC compound, concurrent with final
action to control PCE dry cleaners.
     Response;  The EPA recently proposed adding PCE to the list
of compounds exempt as a VOC on the basis that it has negligible
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photochemical  reactivity and thus  does  not  contribute  to
tropospheric ozone formation.   A proposed rulemaking describing
the addition of  PCE to  the VOC  exempt list  has  been  published in
the Federal Register (57 FR  48490,  October  26,  1992).   The
outcome of that  rulemaking will have no impacts on the dry
cleaning NESHAP.
2.14.2  Carcinogen Risk Assessment Classification of
        Perchloroethylene
     Comment;  Two commenters  (IV-D-14,  IV-D-21) expressed views
on carcinogenic  risk.   One commenter (IV-D-14)  urged the EPA  to
recognize in the preamble to the final  NESHAP the recommendations
of its own Science Advisory  Board  (SAB)  regarding revisions in
the Guidelines for Carcinogen Risk Assessment pertaining to the
classification of  PCE.   The  commenter quoted an excerpt from  the
document, Health Effects Assessment of  Perchloroethvlene.
EPA-SAB-EHC-91-013,  which stated that there is  "no compelling
evidence of human  cancer risk"  from exposure to PCE.   The
commenter recognized that, at this  time, it cannot be
conclusively stated whether  or  not  PCE  is a potential  carcinogen
and, therefore,  concurred with  the  SAB  that further  research  be
pursued to study the health  risks of PCE.
     Another commenter  (IV-D-21) submitted a paper and scientific
articles to support that no  adverse health effects would be
expected at environmental or even workplace levels of  PCE
exposure.
     Response;   In its evaluation of PCE, the SAB recognized  the
difficulty of placing PCE into  one  of the categories designated
in the current Guidelines for Carcinogen Risk Assessment.
Therefore,., in: the-Health Effects Assessment of  Perchloroethvlene.
the SAB recommended that, "when the Guidelines  are revised,  their
flexibility should be endorsed and  strengthened, and that
exceptions to a strict categorization are a practical necessity"
(EPA-SAB-EHC-91-013; page 7).
     The EPA is currently revising the guidelines.   This effort
is not intended to be a solution to the uncertainty about the
carcinogenicity of PCE or any other specific agent.   Revisions

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 are being considered to ensure that the guidelines reflect
 current knowledge about carcinogenic risk.
      At this time,  it is premature to discuss whether the
 revisions to the guidelines may affect earlier classifications of
 chemicals,  and the EPA does not believe it  pertinent to
 speculate.
      Comment;   Two commenters (IV-D-24,  IV-D-25)  cited evidence
 to support that perchloroethylene should be considered a probable
 human carcinogen.   One commenter (IV-D-24)  objected to the
 Science Advisory Board position presented in the  proposal NESHAP
 which stated that "in the spirit of flexibility encouraged by the
 Guidelines,  our best judgment places this compound on a continuum
 between these two categories."  This commenter asserted that  the
 qualitative assessment of the carcinogenicity of  PCE (as
 presented in the NESCAUM Health Evaluation  Document for PCE,
 1986)  concludes that sufficient animal evidence would constitute
 consideration  of PCE as a probable human carcinogen.   This
 commenter further argued that evidence for  carcinogenicity based
 on qualitative indicators of  possible cancer risk to humans
 includes  corroboration of carcinogenicity by more than one
 investigator;  multiple routes of  exposure (oral,  gavage,  and
 inhalation); multiple species;  diversity of  primary tumor
 locations and  types;  evidence of  genotoxicity and structure
 activity relations with, other carcinogens.   Based on findings  of
 this evaluation, this  commenter concluded that  PCE is  a  probable
 human carcinogen and may present  both an  occupational  and public
 health risk to  exposed populations, particularly  to people living
 near the dry cleaning  facility.
     The other  commenter (IV-D-25) pointed out  that, althouglr
 there is some debate about the  carcinogenic classification  of
 PCE, experts agree that  exposure  increases cancer  risk and  should
 be limited.  This commenter cited two  studies by the National
Toxicology program, which recommended:
     the overall carcinogenic evidence for
     tetrachloroethylene would be elevated to Group B2
     meaning that tetrachloroethylene should be considered a
     "probable human carcinogen."
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 This commenter stated that the International Agency for Research
 on Cancer (IARC)  also classifies perchloroethylene as a B2
 carcinogen.

      This commenter cited a letter from the SAB to the
 Administrator:

      As  perchloroethylene illustrates,  the distinction
      between the  B2 and C categories can be an arbitrary
      distinction  on a continuum of weight of evidence .  .  .
      From a  scientific point of view,  it seems inappropriate
      for EPA and  other agencies to regulate substances that
      are classified B2 and not to consider regulation of
      compounds  classified as c,  regardless of the level of
      human exposure ...  A substance classified as c
      (limited evidence in animals)  for which human exposure
      is  high may  represent a much greater potential threat
      to  human health.

      EPA and other  agencies (including those in state
      governments) may,  therefore,  wish to take steps to
      reduce  high  exposures to substances in the C category
      whenever there appears to be a potentially significant
      threat  to  human health .  .  .  Indoor exposure to
      perchloroethylene,  such as  might  be found in dry
      cleaning establishments not using the equivalent of
      good industrial hygiene practices,  could merit actions
      under this criterion.

      Response;  The EPA uses the Guidelines for Carcinogen Risk
Assessmentf  published in the Federal Register on September 24,

1986, to  determine  the  appropriate  weight-of-evidence
classification  for  a chemical.   At  the  present time,  with  the

current guidelines,  the EPA has  not determined whether PCE would
be classified more  appropriately as a B2  or as a C  carcinogen.

Under the  current guidelines,  and with  the present  data, PCE

could be viewed as  a B2  carcinogen,  or  probable human carcinogen.

This  is-,, however-,, only; one; view  in  a range of  views, which,  cover
the C to B2 range.   The  EPA Science Advisory Board  (SAB) presents

the position that,  "in the  spirit of flexibility encouraged by
the Guidelines, our  best judgment places  this  compound on  a

continuum between these  two  categories.H   Uncertainty in the PCE
data base  leads the  SAB  to recommend its  being  classified  on a

continuum between B2 and C.  The EPA has  not adopted any

position, but is considering all views on  the  classification of
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 PCE while also promoting research to reduce uncertainty in the
 data base for PCE.
      The SAB also states that Ma substance classified as c
 (limited evidence in animals)  for which human exposure is high
 may represent a much greater threat to human health" than a
 substance classified as B2.   The EPA agrees that,  since cancer
 risk is likely to increase as exposure to the cancer-causing
 agent increases,  exposure to the agent should be limited.   In
 evaluating the cancer risk posed by a chemical,  the EPA takes
 into account the potency,  weight-of-evidence classification,
 potential for exposure to the chemical,  and other  factors
 relating to behavior of the agent in the environment or in the
 exposed individual.   The high potential for exposure to PCE gives
 support to its being regulated.
 2.14.3   Public Health Impact
      Comment:   One commenter (IV-D-24)  thought that the public
 health  impact of  the proposal  NESHAP was not evaluated
 sufficiently.   This  commenter  stated that the EPA  presented a
 public  health impact analysis  based on a qualitative
 toxicological assessment of  PCE  but neglected to evaluate  other
 criteria  for  determining public  health impacts from PCE exposure,
 such  as the location of emission points  and the  potential  for
 exposure,  fate and transport of  the emissions  (half-life,
 deposition characteristics,  etc.) or the activity  patterns  of
 potentially exposed  populations.
      This  commenter  asserted that the population model  the  EPA
 used  to project national  impacts  was  not appropriate for
 assessing  the  localized public health impact from  area  sources.
 The commenter  believed  that  this  type•-. of  analysis  dilutes•-the-
 actual public health  impacts resulting from exposure to high
 concentrations of fugitive PCE emissions  from dry  cleaners.
     Response;  The  level of detail recommended by the commenter
 for the evaluation of public health  impacts is more extensive
 than necessary for this particular rulemaking.  A population
model that projects national impacts was not used to assess the
 localized public health impact of emissions from area sources for

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this rulemaking.  Estimated national emissions reductions are
discussed in the proposed standard, but impacts on public health
were considered in a qualitative assessment, as noted by the
commenter.
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