EPA-453-R-03-004
        United States
        Agency
  NATIONAL EMISSION STANDARDS FOR
  HAZARDOUS  AIR  POLLUTANTS
  (NESHAP) FOR THE HYDROCHLORIC
  ACID  PRODUCTION INDUSTRY:
  Summary  of  Public  Comments  and
  Responses

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                                                   EPA 453/R-03-004
                                                       January 2003
National Emission Standards for Hazardous  Air Pollutants  (NESHAP]
          for the Hydrochloric Acid Production Industry:
             Summary of  Public Comments and Responses
                                By:
                         EC/R Incorporated
                      Durham, North Carolina
                           Prepared for:
                          William Maxwell
                    Emission Standards Division
                     Contract No.  68-D-01-055
                     Work Assignment No.  1-13
               U.S.  Environmental  Protection Agency
           Office of Air Quality Planning and Standards
                    Emission Standards Division
                         Combustion Group
              Research Triangle Park,  North Carolina


                             U S Environmental Protection Agency
                             Region 5, Library (PL-12J)
                             77 West Jackson Boulevard, 12tn Moor
                             Chicago, II 60604-3590

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                            Disclaimer

     This report is issued by the Office of Air Quality Planning
and Standards, U.S. Environmental Protection Agency.  Mention of
trade names and/or commercial products is not intended to
constitute endorsement or recommendation for use.  Copies of this
report are available free of charge to Federal employees, current
contractors and grantees, and nonprofit organizations-as supplies
permit-from the Library Services Office (C267-01), U.S.
Environmental Protection Agency, Research Triangle Park,  NC
27711, (919-541-2777)  or, for a nominal fee, from the National
Technical Information Service,  5285 Port Royal Road, Springfield,
Virginia 22161,  (703-487-4650).
                               IV

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                 ENVIRONMENTAL PROTECTION AGENCY

 National Emission  Standards for  Hazardous  Air Pollutants for the
             Hydrochloric Acid Production Industry -
         Background Information for Promulgated Standards

                           Prepared by:
Robert Wayland                                     (Date)
Group Leader, Combustion Group
Emission Standards Division
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711

1.   The final National Emission Standards for Hazardous Air
     Pollutants (NESHAP) will regulate emissions of hazardous air
     pollutants from hydrochloric acid production operations.
     Only those operations that are part of major sources under
     section 112(d)  of the Clean Air Act as amended in 1990 will
     be regulated.

2 .   Copies of this document have been sent to the following
     Federal Departments: Labor, Health and Human Services,
     Defense,. Transportation, Agriculture,  Commerce,  Interior,
     and Energy; the National Science Foundation; and the Council
     on Environmental Quality; members of the State and
     Territorial Air Pollution Program administrators; the
     Association of Local Air Pollution Control Officials; EPA
     Regional Administrators; and other interested parties.

3.   For additional information contact:

     Mr.  William Maxwell
     Combustion Group  (C439-01)
     U.S.  Environmental Protection Agency
     Research Triangle Park,  NC 27711
     Telephone:  (919)541-5430

4.   Paper copies  of this document may be obtained from:

     National Technical Information Services (NTIS)
     5285  Port Royal Road
     Springfield,  VA 22161
     Telephone:  (703)487-4650
                               VI

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     U.S.  EPA Library Services Office (C267-01)
     U.S.  Environmental Protection Agency
     Research Triangle Park,  NC 27711

5 .    Electronic  copies of  this document  may be obtained from the
     EPA's OAR Technology  Transfer Network website (TTNWeb).

     The TTNWeb  is  a collection of related Web sites  containing
     information about many areas  of  air pollution science,
     technology,  regulation,  measurement,  and prevention.   The
     TTNWeb is directly accessible from  the Internet  via the
     World Wide  Web at the following  address:

     http://www.epa.gov/ttn
                               vn

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                         TABLE  OF CONTENTS








1 . 0  SUMMARY	1-1





2.0
SUMT'
2.1
2 .2
2.3
2 .4
2 .5
2 . 6
2 .7
2 .8
IARY OF PUBLIC COMMENTS AND RESPONSES 	
APPLICABILITY 	
2.1.1 HC1 Production Facility 	
212 Affected Sources 	
2.1.3 Facilitv-Wide Exemptions 	
2.1.4 Exemptions for Specific Ecmipment . . .
2.1.5 Once In, Always In 	
COMPLIANCE DATES .... 	
2.2.1 Conflict with Electronic Compliance . .
2.2.2 Specific Compliance Extension 	
DEFINITIONS ... 	
2.3.1 Hydrochloric Acid Process Vent ....
2.3.2 HC1/C1, Service 	
2 3.3 Caustic Scrubber 	
2.3.4 Deviation 	
2.3.5 Water Scrubber/Absorber 	
2.3.6 Transfer Operations 	
2 3.7 Storage Tanks .... . ...
2 3.8 Equipment . . . ...
MACT DETERMINATIONS 	 ....
2.4.1 Basis for MACT Standard 	
2.4.2 Determination of MACT Floor 	
2.4.3 Re-Evaluation of MACT Floor 	
2.4.4 Concentration Emission Limitations . .
2.4.5 Transfer Operations 	
2.4.6 Equipment Leaks 	
2.4.7 Wastewater Treatment Operations ....
COMPLIANCE ISSUES 	
2.5.1 Performance Testing 	
2.5.2 Operating Parameters 	
2.5.3 Monitorincr Alternatives 	
2.5.4 Site-Specific Monitoring Plans ....
2.5.5 Other Comments Regarding Monitoring .
2.5.6 Compliance During SSM Events 	
NOTIFICATIONS, REPORTS, AND RECORDS 	
2.6.1 Submission Dates 	
2.6.2 SSM Reports 	 ....
2.6.3 Unnecessary/Burdensome Reporting and
Recordkeeping Requirements 	
2.6.4 Inconsistencies in Proposed Rule . . .
2.6.5 Electronic Recordkeeping 	
2.6.6 Report Addressee 	
EMISSION ESTIMATES 	
COST IMPACTS 	
2.8.1 Assumption of Common Scrubber 	
. 2-1
. 2-1
. 2-1
2-6
. 2-8
2-18
2-23
2-23
2-23
2-24
2-25
2-25
2-26
2-27
2-28
2-29
2-30
2-31
2-31
2-32
2-32
2-37
2-38
2-44
2-49
2-50
2-52
2-53
2-53
2-58
2-60
2-62
2-67
2-68
2-69
2-69
2-70
2-7Q
2-73
2-74
2-74
2-75
2-75
2-76
                                VI11

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          2.8.2     Cost Not Justifiable	2-77
     2.9  MISCELLANEOUS	2-78
          2.9.1     ASTM Method Changes	2-78
          2.9.2     Word Changes	2-79
          2.9.3     Typographical Errors  	   2-80
          2.9.4     Subpart A Comments	2-81
                          LIST  OF  TABLES

Table 1-1.  List of Commenters on the Proposed NESHAP for
     Hydrochloric Acid (HC1)  Production,  40 CFR 63, Subpart
     NNNNN	1-2
Table 2-1.  Process Vent HCl Controls	2-41
Table 2-2.  Process Vent Chlorine Controls	2-42
Table 2-3.  Storage Tank HCl Controls	2-43
Table 2-4.  Transfer Operations HCl Controls	2-43
Table 2-5.  Corrected ASTM Test Method Names	2-79
                                IX

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1.0  SUMMARY

     The United States Environmental Protection Agency  (EPA)
proposed national emission standards for hazardous air pollutants
(NESHAP) for hydrochloric acid (HCl) production on September  18,
2001 (66 FR 48174) under Section 112(d) of the Clean Air Act
(CAA).

     Public comments were requested on the proposed standards and
a total of 19 comment letters were received.   In response to
written requests by commenters (IV-D-02,  IV-D-03),  the comment
period for the proposed rule was extended to December 19, 2001
(66 FR 57917).  The commenters represent hydrochloric acid
producers,  industrial trade organizations,  public,  and other
related organizations.  Table 1-1 presents a list of all persons
that submitted written comments,  their affiliation,  and their
docket  item number.   A public hearing was not requested.

     This document presents a summary of the public comments
received along with responses developed by EPA.   This summary of
comments and responses serves as the basis for revisions made to
the standards between proposal and promulgation.
                               1-1

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  Table 1-1.   List of Cozranenters on the Proposed NESHAP  for
Hydrochloric  Acid (HCl)  Production, 40 CFR 63, Subpart NNNNN.
Docket A-
99-41 Item
Number
IV-D-01
IV-D-02
IV-D-03
IV-D-04
IV-D-05
IV-D-06
IV-D-07
IV-D-08
IV-D-09
IV-D-10
IV-D-11
IV-D-12
IV-D-13
IV-D-14
IV-D-15
IV-D-16
IV-D-17
Commenter and Affiliation
J. Bardi , Administrative Assistant, American
Society for Testing and Materials (ASTM)
A. Dungan, Vice President, Safety, Health,
and Environment, The Chlorine Institute
K. Batt, Dow Chemical Company
L. Tanner, Environmental Engineering
Specialist, 3M Environmental Technology
M. Lopez, et al . , Undergraduate Students,
Florida International University
P. Jann, Senior Regulatory Consultant,
Environmental Section, DuPont Engineering
R. Kelley, Vice President, Environment,
Health, Safety, and Communications, Formosa
Plastics Corporation
D. Foerter, Deputy Director, Institute of
Clean Air Companies (ICAC)
J. Evans, Manager, Environmental Affairs,
Lyondell Chemical Company
A. Till, Ph.D., Pharmaceutical Research and
Manufacturers of America (PhRMA)
M. Collins, Environmental Manager, Cabot
Corporation
N. Morrow, ExxonMobil Chemical Company
J. Mayhew, Vice President, Regulatory and
Technical Affairs, American Chemistry Council
R. Raiders, Lead Environmental Manager,
Atofina Chemicals
R. Smerko, President, The Chlorine Institute
S. Capone, Manager, Air Programs, GE Plastics
C. Schlitter, Environmental Projects Manager,
Kerr-McGee Chemical, LLC
Date of
Document
09-18-01
10-16-01
10-25-01
11-13-01
11-14-01
11-16-01
11-16-01
11-16-01
11-16-01
11-16-01
11-19-01
12-17-01
12-19-01
12-19-01
12-19-01
12-19-01
12-19-01
                             1-2

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  Table 1-1.  List of Commenters on the Proposed NESHAP for
Hydrochloric Acid (HC1) Production, 40 CFR 63, Subpart NNNNN.
Docket A-
99-41 Item
Number
IV-D-18
IV-D-19
IV-D-20
IV-D-21
IV-D-22
Comment er and Affiliation
K. Fay, Global Director, Environment, PPG
Industries, Incorporated
K. Batt, P.E., Regulatory Management
Expertise Center, Dow Chemical Company (Union
Carbide Corporation)
E. Linak, Director Chemical Economics
Handbook, SRI Consulting
G. Brouillette, Environmental Health and
Safety Manager, Borden Chemicals and Plastics
R. Huffman, Environmental Specialist, Bayer
Corporation
Date of
Document
12-19-01
12-19-01
01-02-02
11-12-01
12-19-01
                             1-3

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 2.0  SUMMARY OF PUBLIC COMMENTS AND RESPONSES

 2.1  APPLICABILITY

 2.1.1     HCl Production Facility

     Comment:  Several commenters (IV-D-07, IV-D-12, IV-D-13,  IV-
 D-16, IV-D-17,  IV-D-22) requested that the EPA clarify the
 definition of an HCl production facility to confirm their
 interpretation tha.t a facility must produce,  store, AND transfer
 HCl in order to be considered an HCl production facility.  The
 commenters described many specific configurations of equipment  at
 their facilities and requested confirmation of their assumptions
 regarding whether the collections of equipment would be subject
 to the proposed rule.  Several commenters noted that section
 II.A. of the proposal preamble seems to contradict the definition
 of HCl production facility in proposed §63.8985(a)(1)  because it
 seems to indicate that production of HCl is the only required
 element for a  collection of equipment to be considered an HCl
 production facility.   One commenter (IV-D-16)  suggested that the
 definition of  an HCl production facility be clarified to state
 that it includes an HCl absorber and associated apparatus used  to
 produce and handle liquid HCl product.

     Response:  As noted by several  commenters,  the language in
 the  proposed rule and the description in the preamble were not
 entirely consistent.   This led to the common misinterpretation
 that to be subject to the rule,  an  HCl  production facility had  to
produce,  store,  AND transfer liquid HCl product.   In fact, the
 revised language by commenter IV-D-16 conveys our intent,  which
was  clearly stated in the preamble.   That is,  an HCl production
 facility is one that PRODUCES liquid HCl product,  and,  if
present,  equipment used to store and transfer liquid HCl product
 is included in  the facility.   Therefore,  the final rule contains
 language similar to that suggested  by the commenter to clarify
our  intent.

     Comment: Many commenters (IV-D-06,  IV-D-13,  IV-D-14,  IV-D-
 15,  IV-D-16,  IV-D-17,  IV-D-18,  IV-D-19,  IV-D-20,  IV-D-22)
requested that  the EPA raise the minimum HCl  concentration for  an
HCl  production  facility from.10  weight  percent to a more
appropriate level that accurately represents  commercial
production of HCl.  The commenters 'stated that liquid HCl is
 commonly produced for commerce at 20° to 22°  Baume (Be) acid
 strength (31.45 to 35.2 weight percent).   One commenter (IV-D-13)
corrected mis-information that the  EPA  cited in the proposal
preamble (66 FR 48178)  indicating that  the Hargreaves process
produces HCl at a concentration of  10 weight percent.   The
 commenter clarified that this process produces a byproduct of
hydrogen chloride gas that is 5  to  12 percent by volume,  not

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 weight; the liquid HCl produced by the process is 22° Be.  One
 commenter  (IV-D-19) stated that his company, which is the largest
 manufacturer of HCl in the United States, predominantly produces
 30 to 36 weight percent HCl, although approximately 3 percent of
 the liquid HCl they produce per year is at a concentration of
 less than 20 weight percent.  One commenter  (IV-D-13) added that
 companies do not dilute HCl before shipping it, nor do they
 produce weak HCl and then concentrate it before shipping it.

     Several commenters suggested that the EPA use 30 or 31.45
 weight percent as the minimum HCl concentration,  which would
 still cover producers of commercial grade HCl but would exclude
 incidental production of HCl, while one commenter (IV-D-06)
 recommended a minimum of 20 to 25 weight percent.  According to
 the commenters, the cost of shipping 10 weight percent acid is
 higher than the price of the product,  so distributors of weak HCl
 solutions  (e.g.,  10 weight percent)  typically buy concentrated
 acid in bulk and then dilute it to meet their customer's needs.
 Additionally,  the commenters noted that HCl emissions are a.
 function of vapor pressure which is a function of HCl
 concentration and that,  for a 10 weight percent HCl solution,  the
 vapor concentration of HCl gas in equilibrium with the HCl is
 lower than the proposed emission standard (10.7 parts per million
 by volume  [ppmv]  at 25°C).   One commenter (IV-D-18)  additionally
 noted that the Hazardous Organic NESHAP (HON)  (§63.119)  does not
 require emission controls on storage tanks with HAP vapor
 pressures less than 5.2 kPa,  whereas the vapor pressure of HCl at
 20° Be is 2.41 kPa.   The commenters concluded that the burden
 associated with installing control equipment and conducting
 monitoring, reporting,  and recordkeeping activities is too high
 given that storage tanks containing 10 weight percent HCl would
 already meet the emission limit in the proposed rule.  One
 commenter (IV-D-16)  calculated the annualized control cost for a
 storage tank containing 30 weight percent HCl to be in excess of
 $100,000 per ton of HAP reduced,  and the cost for a tank
 containing 10  weight percent HCl to be in excess of $200 million
per ton of HAP reduced.

     Response:  As discussed in the proposal preamble, our intent
 in establishing a minimum grade/HCl concentration was to separate
 commercial HCl production (which we want the rule to cover)  and
 incidental HCl production (which we do not want the rule to
 cover).   At proposal,  we selected a 10 percent by weight cutoff,
 and specifically requested comments and additional information
 regarding this issue.   We carefully considered all the
 information provided by the commenters,  and agree that the
proposed 10 percent is not an appropriate level to define a
 "commercial" HCl production facility.   Based on the information
provided in these public comments,  we concluded that 30 percent
by weight is the optimum choice.   We believe that this will

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 include the most commonly produced commercial grades (20° to 22°
 Be), while excluding incidental production.   The final rule
 states that an HCl production facility that  produces liquid HC1
 product at a concentration of 30 weight percent of greater is
 subject to the rule.  This means that this unit is subject at all
 times, even those times when a liquid HCl product of a lower
 concentration is being produced.  Therefore,  the final rule will
 cover facilities like the one pointed out by the commenter that
 occasionally produce liquid HCl product at concentrations less
 than 30 percent, even when those lower concentration products are
 being produced.

     However,  we wanted to ensure that facilities that primarily
 produce lower-concentration liquid HCL product not be subject to
 the final rule.   Therefore,  we added a statement in §63.8985 (a)
 that the rule does not cover HCL production  facilities that only
 occasionally produce liquid HCL product at a concentration of 30
 percent by weight or greater. We did not,  however,  include a
 specific definition of what constitutes "occasional production."
 If a facility produces liquid HCL with a concentration of
 30 percent or greater during its normal operations,  this would
 not be considered occasional production.

     Comment:  One commenter  (IV-D-18)  suggested that facilities
 be required to calculate the concentration of HCl they produce as
 an "average concentration,"  defined as in the HON (§63.111)  to be
 a flow-weighted annual average concentration,  because customer
 requirements cause variations in the concentration of HCl
produced by a facility.

     Response:  We recognize that customer requirements can
 change,  resulting in varying concentrations  in HCl products.  In
general,  we believe that a plant that produces 30 weight percent
HCl is not likely to be an "incidental" producer of HCl.   We do
not wish to impose the burden of tracking the concentration of
every bit of product produced and then calculating an annual
 average concentration to determine compliance.  Therefore, we did
not base the applicability on an annual average HCl concentration
 in the final rule.

     Comment:  One commenter  (IV-D-19)  affirmed the EPA's use of
HCl concentration by weight percent to define an HCl production
 facility.   The commenter stated that this measure is easy to
determine and document and is widely used in the industry.  The
commenter further informed the EPA that liquid HCl concentration
 is determined after the acid solution cools  to near ambient
 temperature through either mass balance (using a flow meter) or
 as the ratio of amount of water to anhydrous HCl feed,  and can be
measured manually using ASTM method E224,  or some other method,
 or continuously using a nuclear densitometer.

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     Response: First, we believe  that an owner or operator who
 acknowledges  that their process is  subject  to the rule should not
 be required to measure the HCl concentration.  The only situation
 where measurement of the HCl  concentration  would be necessary is
 demonstrating that a facility is  not subject to the rule.  We do
 believe it would be beneficial to specify methods to use  for
 determining the HCl concentration in liquid products, to  avoid
 confusion regarding applicability determinations.  Therefore, we
 have added provisions to the  rule specifying that ASTM Method
 E224 be used to determine the HCl concentration in liquid
 products,  in instances where  that is necessary.

     Comment: Many commenters (IV-D-06, IV-D-09, IV-D-11, IV-D-
 13, IV-D-15, IV-D-16, IV-D-17, IV-D-19, IV-D-22) requested that
 the EPA clearly delineate where the HCl production facility ends
 and HCl consumption begins so as  not to include equipment
 unrelated to the production of HCl.  Commenter IV-D-11 pointed
 out that the preamble stated  that the HCl production facility
 begins at the point where the HCl-containing stream enters the
 absorber,  but that the rule itself makes no such statement.   This
 commenter suggested that the  rule language  be made consistent
 with preamble language.   Another  commenter  (IV-D-19)  noted his
 agreement with the definition of  the beginning of the HCl
 production facility as the absorber that receives an anhydrous
 HCl stream.

     These commenters stated  that many plants store and transfer
 HCl that was purchased rather than produced on-site,  or store HCl
 produced on-site for use in wastewater treatment,  and that such
 activities should not be covered  by the proposed rule just
 because they are on the same  plant site as  an HCl production
 facility.   One commenter (IV-D-06) suggested that the HCl
 production facility should end with the first HCl storage tank,
 and the first transfer rack,   if applicable,  after the HCl
 production unit (i.e.,  absorber).   The commenter noted that this
 definition would be consistent with the HON's definition  of a
 chemical processing unit (CPU).    Another commenter (IV-D-16)
 described the equipment configurations at three of the company's
 facilities and suggested that the HCl production facility should
 end at the HCl storage tanks  directly connected to the HCl
 absorber (production unit)  and at transfer  racks downstream of
 the storage tanks or absorber.

     One commenter (IV-D-09)   noted that the control cost per  ton
 of HAP removed for storage tanks  that are not located near the
HCl production process is very high because they must have
dedicated control devices and suggested that the HCl production
 facility include only the absorber,  primary HCl storage tanks,
and loading areas associated  with the HCl production unit, so as
 to align the rule applicability with the assumption used  in the

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 cost  impacts analysis that facilities could control all emission
 points with one control device.

      Response: We agree with the commenters that the proposed
 rule  could be improved by clarifying where an HC1 production
 facility begins and ends.  As mentioned by the commenters, the
 preamble was clear regarding our intent of where the facility
 begins.  On page 48178 of the proposed preamble, we indicated
 that  the starting point for an HC1 production facility is where
 an HCl-containing gaseous stream enters the absorber in which the
 liquid HCl is produced.  The final rule is clear in this regard.
 In the final rule, the definition of an HCl production facility
 in §63.8985(a)(1) states that the "HCl production facility begins
 at the point when a gaseous stream containing HCl enters the HCl
 production unit,  ..."  In addition,  the following definition of
 HCl production unit is included in §63.9075:

     HCl production unit means an absorber or other vessel
     in which a liquid HCl product is manufactured by
     absorbing gaseous HCl into either water or an aqueous
     HCl solution.

     Defining the "end" of an HCl production facility is not
 quite so straightforward.  Our intent was certainly that only
 storage tanks and transfer operations that are storing and
 transferring HCl produced at the site be included in the
 facility.  We do recognize,  however,  that the proposed rule could
have been interpreted to be applicable to transfer racks and
 storage tanks that unload and store purchased HCl,  along with any
 other HCl-containing storage tanks co-located at a site with an
HCl production facility that is subject to this rule.   Therefore,
we have made rule changes to clarify our intent.

     In addition to clarifying where the HCl production facility
begins, paragraph §63. 8985(a) (1)  of the final rule also specifies
what is included in the HCl production facility and where it
ends.   Specifically,  it states that the HCl production facility
 includes all storage tanks that contain liquid HCl product that
 is produced in the HCl production unit,  along with all transfer
operations that load HCl product produced in the HCl production
unit into a tank truck,  rail car,  ship,  or barge.  It also
 includes the piping and other equipment used to transfer liquid
HCl product from the HCl production unit to the storage tanks
and/or transfer operations.   The rule clarifies that the HCl
production facility ends at the point that the liquid HCl product
produced in the HCl production unit either leaves the plant site
via a tank truck, rail car,  ship,  barge, or pipeline,  or enters
 another process on the plant site.  We have added a definition of
 "plant site" to the final rule.
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     Comment: Two  commenters  (IV-D-15, IV-D-18) supported  the
 EPA's decision  to  limit  the source category to sources  that
 produce  liquid  HCl,  as opposed to gaseous HC1.  Several
 commenters  (IV-D-12,  IV-D-13, IV-D-14) requested clarification  of
 the  terms  "produce"  and  "HCl production" to ensure that certain
 activities are  excluded.  The commenters requested that the HCl
 production facility  definition include the following language:
 "produced by the scrubbing of a gaseous stream containing  HCl"  so
 as to exclude operations that produce HCl by other means.  The
 commenters requested further clarification that liquid  streams
 produced by the caustic  scrubbing of a stream containing HCl are
 not  "liquid HCl product" because they contain sodium chloride not
 hydrogen chloride.

     Response: We  have clarified this point in accordance  with
 the  commenters' suggestion.  We believe that it is appropriate  to
 clarify this point because the information available to us
 indicates that all processes that produce liquid HCl product do
 so through the scrubbing of gaseous streams containing HCl.
 Specifically, we have added a definition of HCl production unit
 (provided above) and we have stated that an HCl production
 facility begins at the point where a gaseous stream containing
 HCl  enters the HCl production unit.   We agree that the caustic
 scrubbing of streams containing HCl should not be covered by the
 rule, but do not believe that it is necessary to specifically
 exempt such processes because, as pointed out by the commenter,
 they produce sodium  chloride,  not hydrogen chloride.

 2.1.2     Affected Sources

     Comment: Several commenters (IV-D-12,  IV-D-13,  IV-D-16)
 requested that the EPA re-define the "affected source" to  include
 all of the individual "HCl production facilities" located at one
plant site.  The commenters noted that this change would be
consistent with the proposed revisions to §63.2 of the General
 Provisions.  One commenter (IV-D-12)  pointed out that defining
 each HCl production  facility at a plant site as its own affected
 source could create problems with compliance schedules and result
 in duplicate testing, reporting,  and recordkeeping if,  for
example,  a storage tank is shared by a new affected source and  an
existing affected source.  One commenter (IV-D-16)  recommended
 resolving such a problem by assigning shared equipment to  the
affected source with the highest annual production of liquid HCl
product.   Two of the commenters (IV-D-12,  IV-D-13)  suggested the
 following language for including all HCl production facilities  in
one affected source:  "The affected source is one or more HCl
production facilities at a plant site,  which contain the
collection of emissions streams listed..."   Another commenter
 (IV-D-16)  also suggested that the following statement be added  to
the definition of HCl production facility in §63.8985(a) (1) :

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 "Each HCl absorber used to produce liquid HCl product, along with
 its associated equipment,  constitutes a separate HCl production
 facility."

     Response -.  At a single plant site,  there can be multiple HCl
 production facilities that are independent and originate from
 totally different types of processes.  At proposal, we assumed
 that it would be simpler and "cleaner"  for owners and operators
 to treat each independent HCl production facility as a separate
 affected source.  However, these comments raised concerns with
 this approach.   We prefer the approach of combining all HCl
 production facilities in one affected source to that of creating
 complicated provisions to assign shared HCl storage tanks to a
 specific HCl production unit.  Therefore,  we have incorporated
 the language suggested by Commenters IV-D-12 and IV-D-13 in the
 definition of the affected source in the final rule.  We do not
 feel that it is necessary, in the definition of HCl production
 facility,  to specify that each absorber and associated equipment
 is a separate production facility,  especially in light of the
 change to the scope of the affected source.

     Comment:  One commenter  (IV-D-19) requested that the EPA
provide a method for facilities to determine whether multiple-
 service storage tanks are part of the HCl production affected
 source.   The commenter suggested that the EPA use language
 similar to that used in the HON (§63.100 (g))  for determining
whether a storage tank is part of the source to which the rule
 applies.

     Response:  We believe that the changes made to the HCl
production facility definition in §63.8985(a)  largely eliminate
 the need for provisions to assign storage tanks to specific
process units.   In addition,  we have specifically stated in
 §63.8985(a)(2)  of the final rule that storage tanks that are
dedicated feedstock tanks for another process are not part of the
HCl production  facility.   Therefore,  we did not add HON-like
 language in the final rule.

     Comment:  One commenter  (IV-D-14) requested that the rule
include specific provisions for emission points that vent
combined emission streams from a process subject to the proposed
rule and one or more other processes subject to other NESHAP.
The commenter requested that the EPA promulgate a procedure for
distinguishing  between the individual emission streams in a
combined emission stream in order to ensure that a facility is in
compliance with all applicable standards.   If the EPA decides
 that such a procedure would not be feasible,  the commenter
 suggested that  the proposed rule be revised to allow facilities
 to meet a performance based standard (e.g.,  control efficiency)
and that the EPA allow the combined emission streams to comply

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 with any applicable MACT  that is promulgated before the
 compliance date of the proposed rule instead of complying with
 the proposed rule.

     Response: As discussed in section 2.4.4, the final rule
 contains an alternative emission limitation in the form of a
 control efficiency.  This should provide a mechanism for
 compliance for combined emission streams.  Owners or operators  of
 HCl production affected sources will be required to demonstrate
 compliance with this rule, although we have also added provisions
 to the final rule to allow results of previous tests to be used
 to demonstrate compliance with this rule (see section 2.5.1) .

     Comment:  Two commenters  (IV-D-12,  IV-D-13) requested that
 the EPA clarify that the emission limitations and work practice
 standards apply only to affected sources.  The commenters stated
 that,  as written,  §63.9000 and Table 1 could be interpreted to
 mean that the requirements apply to emission streams that are not
 part of an affected source.  The commenters suggested the
 following language to add to §63.9000(a)  and (b)  and Table 1:
 "for each emission stream or leak listed in §63.8990(b) that is
 part of an affected source..."

     Response:  We agree that changes in this section of the rule
 could improve the clarity.  However, we have revised it in a
 different manner than suggested by the commenters.  The language
 used in the final rule is as follows: "you must meet the
 applicable emission limit and work practice standard in Table 1
 to this subpart for each emission stream listed under
 §63.8990(b)(1)  - (4)  that is part of your affected source."

     Comment:  Two commenters  (IV-D-09,  IV-D-12) supported the
 EPA's  decision to include wastewater treatment operations in the
 affected source,  even though no emission limitations apply to
 them.   One commenter (IV-D-12) stated that including wastewater
 treatment operations in the affected source was appropriate
because it would alleviate the burden associated with dealing
with such sources on a case-by-case basis in the future.

     Response:  This provision has been retained in the final
 rule .

 2.1.3      Facility-Wide Exemptions

     Comment:  Several commenters (IV-D-04,  IV-D-06,  IV-D-07, IV-
D-13,  IV-D-14,  IV-D-16,  IV-D-17,  IV-D-18, IV-D-22) requested that
 the EPA exempt from the proposed rule HCl production facilities
 that produce less than a certain amount of liquid HCl per year
 ("small quantity generators").  The commenters stated that this
would eliminate burdensome compliance requirements for a facility

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 that emits very little HC1.  Several commenters  (IV-D-13, IV-D-
 14, IV-D-17) stated that some facilities produce less than 0.4
 gigagrams of liquid HC1 per year, often incidentally, and
 suggested that the EPA exempt facilities that produce less than  1
 gigagra'm  (1,000 Mg) of 100 percent liquid HCl per year,  as
 consistent with the SOCMI NSPS  (§60.660(c) (5) ,  §60.700(c) (3) ) .
 Another commenter  (IV-D-16) suggested that the EPA use 1 Mg/yr of
 liquid HCl as the minimum production level.   Another commenter
 (IV-D-18) cited the Benzene Waste Operations NESHAP  (40 CFR  Part
 61 Subpart FF)  as an example of a rule that used 10 Mg/yr as  the
 minimum production level.

     Response:  As stated above,  our intent is that this rule  not
 cover incidental production of HCl.  We believe that the 30
 weight percent cutoff in the final rule will help to ensure  that
 such incidental producers are not made subject,  so we have not
 included a production-based exemption in the final rule.

     Comment:  Several commenters (IV-D-06,  IV-D-13,  IV-D-14,  IV-
 D-17,  IV-D-18,  IV-D-22)  requested that the EPA exempt from the
 proposed rule HCl production facilities that emit less than  a
 certain de minimis level of HAP per year.   The commenters stated
 that such an exemption would eliminate burdensome compliance
 costs while insignificantly reducing the environmental benefit.
 Two commenters  (IV-D-15,  IV-D-18)  reinforced this statement by
 affirming the EPA's exclusion of HCl  production facilities that
 are not part of major sources.   One commenter (IV-D-13)  stated
 that it was unlawful for the EPA to subject to the proposed rule
HCl production  facilities that emit small  amounts of HCl and are
not by themselves major sources (e.g.,  don't emit more than  10
 tons per year of any one HAP or more  than 25 tons per year of
 total HAP) but  are co-located with major sources.  Another
commenter cited the Marine Tank Vessel Loading Operations NESHAP
as an example of a rule that exempted operations that emit less
 than major source thresholds even if  the operations  are co-
 located at a major source.

     Several commenters provided suggestions for a de minimis
cutoff level.   One commenter (IV-D-06)  noted that other rules
 (e.g.,  Benzene  Waste Operations NESHAP,  Pharmaceutical NESHAP)
have used 10,000 pounds (5 tons) of HAP emissions per year as the
de minimis threshold value.  One commenter (IV-D-17)  suggested
that the EPA use 10 Mg (11.0 tons)  of 100  percent HCl emissions
per year as the de minimis threshold.   Another commenter  (IV-D-
 18) suggested that the EPA exclude HCl production facilities  that
have a potential to emit less than or equal to 1 Mg  (1.1 tons) of
HAP per year.   Another commenter (IV-D-14)  cited the Pesticide
Active Ingredient NESHAP (§63.1362(b)(3)(i))  which has a de
minimis threshold of 6.8 Mg (7.5 tons)  per year of combined  HCl
and C12  emissions  from all  process  vents.  One commenter (IV-D-

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 22) suggested  that  the proposed  rule  follow the example set  forth
 in RCRA standards  (40 CFR 264.343) and require no further
 controls for facilities that emit  less than 1.8 kilograms of HC1
 per hour.

     Response: For  this rule, we do not believe that an exemption
 based on emissions  is practical.   If  such an exemption were
 established, we believe that a standardized method for measuring
 these emissions would need to be included in the rule, and
 sources producing HCl would need to monitor and keep records to
 demonstrate that their emissions were below the cutoff.  As noted
 above, we have incorporated a cutoff based on HCl concentration
 (30 weight percent) into the final applicability requirements.
 We believe that such a cutoff is much more practical and less
 burdensome for HCl producers that  are not subject to the rule.

     Comment:  Several commenters (IV-D-07, IV-D-12,  IV-D-13, IV-
 D-14,  IV-D-16,  IV-D-19) requested  that the EPA explicitly state
 that certain types of HCl production are exempt from the proposed
 rule.   Following are the specific  exemptions requested, along
 with our response to each.

     Comment:  One commenter (IV-D-07)  requested that the EPA
 revise the definition of HCl production facilities to exempt
 facilities for which HCl is not the primary product.   The
 commenter referred the HON (§63.101)  for definitions of
 "product," "by-product," and "chemical manufacturing processing
 unit"  that limit the applicability to facilities that produce a
 specific listed chemical as their primary product.

     Response:  The primary product concept is not relevant to
 this rule,  as the only processes that are subject to the final
 rule are those that intentionally manufacture liquid HCl product.
 There  are a variety of types of processes that generate HC1-
 containing gas streams that provide the feed to the HCl
 production unit.   The rule is "blind"  to the type of process
 generating this HCl-containing stream, and the HCl production
process starts when this gaseous stream enters the absorber where
 the liquid product is made.   We were very clear on this point in
 the proposed preamble (66FR 48178).  We continue to believe that
 if a commercial-level liquid HCl product  (see comments and
 responses  above related to 30 weight percent as the defining
 characteristic of a "commercial-level" HCl product)  is produced
 from any HCl-containing gaseous stream,  whether this stream is a
by-product,  co-product,  waste stream,  etc.,  the unit producing
 the liquid HCl product should be in the source category.

     Comment:  Two commenters (IV-D-12, IV-D-13) listed the
 following specific liquid streams  that should be exempted from
 the definition of HCl production: process byproduct streams

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containing metal chlorides, process byproduct streams containing
HCl not produced through water scrubbing,  boiler feed water bed
regeneration wash water, and catalyst bed wash water.

     Response:  We believe that other changes made to the final
rule make specific exemptions for these processes unnecessary.
For example, §63.8985(a)(1) and the definition of HCl production
unit clarify that processes that absorb gaseous HCl into water or
an aqueous HCl solution are the only HCl production processes
covered.  Also, the 30 weight percent cutoff should ensure that
wash water processes are not subject.  Therefore,  specific
exemptions for these processes are not included in the final
rule .

     Comment:  Several commenters (IV-D-06,  IV-D-14,  IV-D-16, IV-
D-17)  requested that the EPA explicitly exempt HCl production
that results from the proper operation of  air pollution control
devices (APCD)  that are required to be installed in order to meet
applicable requirements, such as water scrubbers that have HCl as
either an input or an unwanted output.  The commenters asserted
that HCl produced in this way should not be considered "HCl
production" because the scrubber liquid,  which contains HCl, is
considered a waste stream and is neutralized by the addition of
caustic to the scrubber or at the point of  disposal of the
liquid.  The commenters noted that such APCDs are already
permitted and subject to emission standards and monitoring,
reporting, and recordkeeping requirements.

     Response:  We agree with the commenters that HCl produced
from the proper operation of air pollution  control devices should
not be subject  to the rule.  However, we did not add such an
exemption in the final rule because we believe that the 30 weight
percent cutoff  will effectively eliminate  such processes from
applicability to this rule.  In turn, if 30 weight percent HCl is
produced from the proper operation of a control device or any
other  source,  we do not believe it is unreasonable for the
process to be subject to this rule.

     Comment:  Two commenters (IV-D-14) requested confirmation and
clarification that facilities that make HCl incidentally and
dispose of it because it is not intended for sale should be
exempted from the proposed rule.   One commenter (IV-D-16)
requested that  the EPA clarify that consumption of HCl, whether
it was purchased or produced on-site, is not covered by the
proposed rule.   One commenter (IV-D-19)  requested that the EPA
clarify that dilution of a concentrated HCl stream is not  "HCl
production."  The commenter explained that  dilution is performed
by adding de-mineralized water to an aqueous HCl solution and
does not result in significant emissions.   The commenter further
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 added  that  dilute HCl solutions have very low vapor pressures
 and, therefore, very low emissions.

     Response: As discussed in response to several previous
 comments, we have made several changes to ensure that
 incidentally-produced HCl is not  subject to the rule.  We also
 believe  that changes in §63.8985(a)(1) related to the HCl
 production  facility definition, along with the addition of a
 definition  of HCl production unit, make it clear that dilution  of
 a concentrated HCl product would  not be covered by the final
 rule.  Therefore, we did not add  a specific exemption for either
 of these situations in the final  rule.

     Comment: Several commenters  (IV-D-12, IV-D-13, IV-D-16, IV-
 D-22) requested that scrubbers that operate as HCl production
 units for fewer than 300 hours per year be exempted from the
 proposed rule.  The commenters cited the HON (§63.160(a),
 §63.162(e)) as an example of a rule with such an exemption.  The
 commenters  stated that a scrubber that is designed for occasional
 use does not generate significant HCl emissions.  One commenter
 (IV-D-16) described a scrubber at his company's facility that is
 only active for HCl production during times when the HCl
 production process is shut down.   The vent from the scrubber is
 controlled by a water scrubber that was installed to meet State
 permitting requirements but might not meet the proposed HCl
 standards and would be difficult  to test because the HCl
 production process would have to be shut down.

     Response: We believe that the 30 weight percent HCl
 criterion reasonably distinguishes commercial level production of
 HCl.   Therefore,  we have not added an exemption for sources that
 operate less than 300 hours per year.

     Comment: Several commenters  (IV-D-04, IV-D-12, IV-D-13, IV-
 D-22)  requested that the EPA add an exemption to the rule for
 research and development (R&D)  facilities.  The commenters stated
 that R&D facilities produce and emit very small amounts of HCl
but can be located at major source sites and,  therefore,  subject
 to the proposed rule.   The commenters noted that the CAA directed
 the EPA to establish a separate source category for R&D
 facilities and that,  accordingly,  the EPA has included an R&D
 exemption in virtually all recently-promulgated NESHAP.   The
 commenters stated that R&D facilities were not considered during
 the rule development process and concluded that it did not appear
as though the EPA intended for R&D facilities to be subject to
 the proposed rule.   One commenter (IV-D-04)  further requested
 that the proposed rule include a definition of  "research and
development activities."
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     Response: We think that the 30 weight percent criteria
 exemption should ensure that R&D facilities not be subject to
 this rule.  However, the commenter is correct in that we have
 included an exemption for R&D in most part 63 NESHAP.  Therefore,
 we have added a definition of R&D facility, along with an
 exemption.

     Comment:  Several commenters (IV-D-06, IV-D-07, IV-D-09, IV-
 D-13, IV-D-15, IV-D-18,  IV-D-22) supported the EPA's decision  to
 exempt from the proposed rule HCl production facilities that are
 already subject to certain other NESHAP, but requested that the
 EPA broaden the exemption to include facilities subject to any
 other NESHAP,  whether it is already promulgated or yet to be
 promulgated.  One commenter (IV-D-13)  further suggested that the
 final HCl rule allow facilities that become subject to another
 NESHAP subsequent to the promulgation of the HCl rule be allowed
 to choose which rule to comply with,  without delaying the
 affected source's compliance date beyond that specified in the
 final HCl rule.

     Three commenters (IV-D-13,  IV-D-15, IV-D-18)  also requested
 that facilities that already have a federally enforceable air
 permit that requires 95  percent (suggested by IV-D-13) or
 99 percent (suggested by IV-D-15 and IV-D-18)  removal efficiency
 be exempted from the proposed rule.   The commenters noted that a
 facility that  is already in full compliance with a NESHAP or
 other federally enforceable requirement should not have to assume
 additional and burdensome testing,  monitoring,  reporting,  and
 recordkeeping  requirements.

     Several commenters  (IV-D-12,  IV-D-13, IV-D-19, IV-D-21,  IV-
 D-22)  requested that the EPA clarify and/or expand exemptions  in
 the proposed rule for facilities subject to other rules.   Two
 commenters  (IV-D-12,  IV-D-13)  requested that the exemption in
proposed §63 . 8985(c) (1)  for facilities subject to §63.113(c)  of
 the HON be clarified to  also exempt facilities that comply with
 the referenced section of the HON because they are required by
another rule to do so.   The commenters also requested that
 facilities  that are complying with §63.994 of Subpart SS (the
 "standard standards"),  which is equivalent to §63.113(c)  of the
HON,  be specifically exempted from the proposed rule, regardless
 of which subpart referred the facility to §63.994.

     One commenter (IV-D-10)  requested that the proposed rule
explicitly exempt facilities that are  subject to the
 Pharmaceutical MACT (40  CFR Part 63,  Subpart GGG).   In the
proposal preamble,  the EPA acknowledged that the Pharmaceutical
MACT also regulates HCl  streams, but did not specifically exempt
 these facilities because it did not believe they produced HCl  in
 sufficient  concentrations to be subjected to the proposed rule.

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 The commenter stated  that  every HCl  recovery process at  a
 pharmaceutical manufacturing  facility  is covered by the
 Pharmaceutical MACT and  that  subjecting those operations to  the
 proposed HCl rule would  discourage facilities from recycling HCl.

     One commenter  (IV-D-19)  requested that the specific
 exemptions for operations  that produce liquid HCl following  the
 incineration of chlorinated waste gas  be expanded to include
 operations that produce  liquid HCl following an incinerator
 subject to RCRA interim  standards  (40  CFR Part 265 Subpart O)  or
 permit requirements  (40  CFR Part 264 Subpart 0).   The commenter
 noted that exemptions in the  HON referenced the RCRA provisions
 (§63.116(b)(5),  §63.138(h)(1)).

     Response:  Just like the  commenters,  we are interested in
 avoiding overlapping situations where  a process that produces HCl
 might be subject to more than one federal regulation.  At
 proposal,  we exempted processes that were subject to several
 specific standards,  and  asked for comments on other potential
 overlaps.   Based on the  comments received,  we have added
 exemptions for processes subject to  the Pharmaceutical MACT  (40
 CFR 63 subpart GGG), and §63.994 of  subpart SS.  We have also
 expanded the exemption to  include any  process required by another
 rule to comply with §63.113 (c) of the  HON.   In addition,
 according to our proposed  decision not to regulate C12  and  HCl
 emissions from chlorine production (67 FR 44713;  July 3, 2002),
 we consider direct synthesis HCl production units that are
 directly associated with chlor-alkali  facilities  to be part  of
 the chlor-alkali facilities.   Therefore,  an exemption has been
 added in the final rule  to exempt direct synthesis HCl production
 processes  that are part of chlor-alkali facilities.

     We believe that the exemption in  the proposed rule for
processes  subject to 40 CFR 264.343(b), which has been retained
 in the final  rule,  adequately addresses the concerns of Commenter
 IV-D-19.

     We exempted the specific situations raised by commenters.
However,  we cannot include a generic exemption for "any other
NESHAP" or any federally enforceable permit.   We  will consider
 such situations  on a case by case basis under a request for  an
alternative non-opacity emission standard submitted in accordance
with §63.6(g).

     Comment:  One commenter (IV-D-9)  described the configuration
at their plant,  where the emissions from their HCl production
 facility were commingled with streams  from other  processes and
 routed to  a liquid hazardous waste incinerator subject to 40  CFR
 63, subpart EEE,  which does include emission limitations for
chlorine and HCl.   The commenter points out that  this situation

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 is  not  covered  by  the  exemption  in  the proposed rule because  the
 "operations  that produce the HCl" are not  subject to subpart  EEE,
 only  the  incinerator to which the emissions are routed.   The
 commenter suggested that the rule specify  that processes  are  not
 subject to the  rule if the process  vent emissions are routed  to
 an  incinerator  regulated under 40 CFR 63,  subpart EEE.

      Response:  While this commenter raised this issue in  regard
 to  exempting entire HCl production  facilities, it is actually an
 issue of  exempting specific emission streams that are routed  to  a
 shared control  device.  We feel  that it is necessary to
 demonstrate compliance with the  provisions of this rule in
 situations where emissions from  an  affected source are routed to
 a shared  control device.  Therefore, we have not added the
 specific  exemption requested.  We would point out that we have
 made  several changes to reduce the burden  in these situations,
 such  as establishing a percent reduction emission limitation  and
 allowing  the use of previous test results  to demonstrate
 compliance.

      Comment: Another commenter  (IV-D-21)   described the
 configuration of equipment at his facility and requested  two
 specific  clarifications of the exemptions  for operations  that
 produce liquid  HCl following the incineration of waste gas
 streams:  (1)  clarify whether the intent was to exempt only the
 production equipment (e.g.,  absorber)  or to also exempt the
 equipment  that  supports the production unit (e.g.,  storage tanks,
 transfer  operations);  and (2)  whether incineration of liquid
 and/or solid waste was intended  to be exempted or only
 incineration of gaseous material.

      Response:  Our intent is to  exempt storage tanks,  transfer
 operations, and all other equipment associated with an HCl
 production unit following the incineration of a waste gas stream.
 We agree with the commenter that this intent was not clear in  the
 proposed rule.  Therefore,  we have clarified this point by
 specifically exempting HCl production facilities (which are
 defined to include tanks,  transfer operations,  etc.)  following
 the incineration of waste gas streams,  and not just the
 "operations that produce liquid HCl."

     We also have made changes in response to the commenter's
 second point.   Specifically,  we have revised the language to
 include the incineration of "chlorinated waste gas streams, waste
 liquids,  or solid wastes."

     Comment: One commenter (IV-D-22)  requested that the
 following  statement made in the proposal preamble be changed
because it creates confusion regarding overlap between HCl
production facilities and HON facilities:   "While the HCl

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production process would be part of the HON affected source,  the
HCl emissions from these operations are not covered by the HON."
The commenter stated that the sentence appears to make certain
HCl production processes part of HON facilities, while at the
same time subjecting them to the proposed HCl rule, seemingly
creating the regulatory overlap that the EPA was trying to avoid.

     Response:  Unfortunately, the situation does exist where  the
same emission stream could be subject to both the HON and the HCl
production MACT.   Consider a chemical manufacturing process unit
that produces ethylene dichloride (EDC) with an anhydrous HCl by-
product.  If the stream is routed to an absorber where 30 weight
percent HCl liquid product is produced, the vent from that
absorber would be subject to this HCl production NESHAP.
However, the owner or operator would also need to calculate the
total resource effectiveness (TRE)  index value of the stream  to
determine if the organic HAP would require control under the  HON.

     An alternative that would eliminate this overlap would be to
revise the HON to require control of HCl,  in addition to the
control of organic HAP.  We believe that the potential regulatory
overlap for a few plants with the current approach would be less
burdensome than a major revision to the HON.

     Comment:  Several commenters (IV-D-06,  IV-D-13, IV-D-14,   IV-
D-16,  IV-D-18,  IV-D-19) supported the proposed exemption for
facilities that recycle all HCl production emissions streams  or
route them to another process,  but requested that the exemption
be clarified and expanded.   One of the commenters (IV-D-06)
recommended that legitimate on-site reuse of HCl should be
exempted from the rule, because it is a beneficial activity that
avoids the need to purchase new raw material.   The commenter
stated that the proposed rule seems to penalize beneficial reuse
of HCl by imposing emission limitations on facilities that
capture HCl in an absorber and reuse it while not imposing
emission limitations on facilities that discard HCl from a
process stream and purchase new HCl for on-site use rather than
reclaiming it.   The commenter stated that his company has a
process that recycles the emissions from an absorber vent and
sends the liquid HCl product directly to another process,  but the
process has a surge control vessel for balancing the production
and consumption rates.   The commenter stated that such a process
should be exempted from the proposed rule even though the surge
control tank does vent minimal emissions through a conservation
vent.

     Another of the commenters (IV-D-13)  requested that the EPA
exempt facilities that produce HCl as an intermediate product and
consume it in another on-site production process.  The commenter
noted that some such facilities could be exempted under the

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 exemption in proposed §63.8985(d) for streams that are recycled
 or routed to another process before being discharged to the
 atmosphere,  but wanted explicit exemption of all such facilities.

     Response: We certainly support the recycling and re-use of
 potential waste materials, including HC1.   Further,  we are aware
 that much of the HCl produced is used by other processes on the
 plant site.   However, we do not see a distinction between these
 processes and processes where the HCl product is truly "sold."
 We believe an exemption like the one cited by the commenter would
 unfairly favor large integrated facilities.   Consider two similar
 HCl processes with similar equipment,  similar production
 capacities,  and similar emissions potential.  We do not believe
 that distinguishing between these processes  based on "where" the
 HCl is consumed is warranted.   We did,  however,  retain in the
 final rule the exemption for processes that  have no discharges to
 the atmosphere from process vents,  storage tanks,  or transfer
 operations.

     As we have consistently stated,  our intent is to cover HCl
production processes that produce commercial-level concentrations
and quantities of liquid HCl product.   We  believe that the
30 weight percent HCl criterion reasonably distinguishes
commercial level production of HCl.

     Comment:  One commenter (IV-D-16)  requested a specific
exemption for recycling HCl that is  used at  a catalyst.   The
commenter described the process at  his facility as follows:
anhydrous HCl is input to a process  as a catalyst,  the outlet
stream from  the process contains HCl,  water, product and
unreacted raw material;  gaseous water and  HCl are separated from
the outlet stream and sent to  condensers and absorbers for
recapture of the aqueous HCl which  is converted to anhydrous HCl
for reuse in the process.   The commenter stated that the capture
of HCl for reuse does not constitute "production"  and should not
be covered under the proposed  rule.

     Response:  As discussed at proposal and  in response to
numerous comments in this document,  our approach for the
applicability for this rule was to  separate  the production of an
HCl product  from incidental production of  HCl using a
concentration cutoff, which is 30 percent  by weight in the final
rule.   It is not feasible to base the applicability on the
processes generating the anhydrous  HCl or  the processes using the
liquid HCl product.   Therefore,  for  the commenter's process, if
the liquid product from the absorbers used to "recapture" the
aqueous HCl  is 30 weight percent HCl or greater, we would
consider it  to be an HCl production facility and it would be
subject to the rule.
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2.1.4     Exemptions for Specific Equipment

     Comment: Several commenters  (IV-D-13, IV-D-14, IV-D-19)
requested that the proposed rule exempt individual emission
streams that are recycled or routed to other processes, rather
than requiring all of the emission streams to be recycled or
routed to other processes in order to be exempted.  The
commenters stated that this revised exemption would serve to
encourage pollution prevention in the case where a process vent
stream is recycled but the liquid HCl product is sent to storage
tanks and transfer operations that would be affected,  whereas the
existing exemption discourages recycling in this case.  One
commenter (IV-D-13) further stated that there is no need to
impose emissions limitations on equipment that does not emit HAP
because the outlet is recycled or routed to another process.  One
commenter (IV-D-19) pointed out that the proposal preamble states
that an absorber whose outlet stream is recycled or routed to
another process is "no longer part of the HCl production facility
affected source" and requested that the rule text include such a
clarification.  The commenter specifically requested that gaseous
streams from HCl production facilities that are routed to a
powerhouse or process heater for use or reuse as fuel be exempted
from the rule, as per the HON (§63.107).

     Response: We agree with the commenters that specific streams
recycled or routed to other processes should not be subject to
the rule,  in addition to the facility-wide exemption where all
emission streams are recycled or routed to other processes.
However,  we do not feel that the most effective manner of
handling this is by exempting these emission streams,  primarily
because they are not "emission"  streams if they are not emitted.
Therefore,  we addressed this issue by defining an "emission
stream" as a gaseous stream that is discharged to the atmosphere.
If the stream is recycled or routed to another process,  it would
not be an emission stream and therefore,  would not be subject to
the final rule.   Following is the specific definition of
"emission stream" in the final rule:

          Emission stream means  a gaseous stream
          originating from an HCl process vent,  an HCl
          storage tank,  an HCl transfer operation,,
          leaking equipment in HCl service,  or HCl
          wastewater operations  that is discharged to
          the atmosphere.   Gaseous streams that are
          routed to another process or recycled for
          reaction or other use  of the HCl and/or
          chlorine (i.e.,  for pH control)  are not
          emission streams.   Gaseous streams from HCl
          transfer operations that are vapor balanced
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          to an HCl storage tank subject to this
          subpart are not emission streams.

     With regard to the requested exemption for streams routed  to
 a powerhouse or process heater, we would point out very
 significant differences between this rule and the HON.  The HON
 regulates emission of organic HAP,  which have a fuel value and
 are destroyed in a combustion device.  Neither of these facts are
 true for HCl and chlorine, which are covered by this rule.
 Therefore, we do not believe that such an exemption is
 appropriate for this rule.

     Comment:  Several commenters (IV-D-09,- IV-D-13)  requested
 that individual vent streams from HCl production facilities that
 are routed through a control device that is installed to comply
 with another NESHAP also be exempted from the proposed rule.  Two
 commenters (IV-D-13,  IV-D-15)  requested that individual emission
 points be exempted if they already have control equipment and are
 subject to any federally enforceable emission standard that
 requires at least 95 percent removal efficiency for HCl and
 chlorine, as is done in the HON (§63.113(c)(ii))  for
 "grandfathered" equipment.

     Response:  We did not make any changes in the final rule in
 response to these comments.   First,  we feel that it is necessary
 to demonstrate compliance with the provisions of this rule, even
 for shared control devices.   General exemptions of the type
 suggested by the commenter would not ensure that the emission
 limitations required for the HCl production industry would be
met.   In fact,  a 95 percent emission limitation is considerably
 less stringent than the emission limitations in the final rule.
 Exempting such facilities would create inequities within the
 industry.  We would point out that we have made several changes
 to reduce the burden in these situations,  such as establishing  a
percent reduction emission limitation and allowing the use of
previous test results to demonstrate compliance.

     Comment:  One commenter (IV-D-13)  requested that the EPA
 explicitly state that storage tanks and transfer racks that are
used to store and transfer HCl that was purchased rather than
produced on-site are not covered by the proposed rule, whether  or
 not the plant site contains an HCl production facility.

     Response:  Storage tanks and transfer racks used to store and
 transfer purchased HCl should not be subject to the HCl
production MACT.  The changes we have made to the definition of
HCl production facility make this clear.  Specifically, final
 §63.8985(a)(1)  states that an HCl production facility subject to
 the rule includes tanks that store product produced in the HCl
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 production  unit  and  transfer  operations  that  load  HCl product
 produced in the  HCl  production  unit.

      Comment: One  commenter  (IV-D-16)  requested  clarification
 that  process vents that are not  associated with  the production of
 HCl are  not covered  by the proposed  rule.  The commenter  stated
 that  the definition  of a  "hydrochloric acid process vent"  ("a
 process  vent through which an emission stream containing  HCl is
 vented to the atmosphere") does  not  make  this clear because it
 does  not define  "process vent"  in  the  context of the definition.

      Response: The commenter  is  correct  in that we only intend to
 cover process vents  associated with  the production of HCl.  We
 have  made this clear in the final  rule in the definition  of HCl
 process  vent, which  states that  an HCl process vent is a  point of
 discharge originating from an HCl  production  unit.

      Comment: Several commenters  (IV-D-14, IV-D-15, IV-D-18, IV-
 D-22) requested  that the EPA  exclude from the affected source
 storage  tanks that are used to store HCl  for  wastewater treatment
 (e.g., pH control of wastewater).  One commenter inquired as to
 whether  a storage tank that receives HCl directly  from an HCl
 production  unit  and  is used solely for wastewater  treatment would
 be included in the affected source.

      Response:  We agree that  storage tanks storing HCl for pH
 control  of  wastewater should  not be  subject to this rule,  because
 this  rule is designed to cover emission sources from the
 production  of HCl, not the use of  HCl.  Therefore, we have
 specified in §63.8985(a)(2)  that HCl storage  tanks dedicated for
 use in wastewater treatment are not  considered to be part of an
 HCl production facility,  and  therefore, not subject to the
 provisions  of the final rule.

      Comment: One commenter (IV-D-09)  requested clarification
 that  the  affected source does not  include equipment that  is
 connected to an HCl  production unit but is owned by another
 company.   The commenter suggested  that "located or co-located  at
 a major  source" be added to the definition of an HCl production
 facility  to indicate that only equipment located at the major
 source that produces HCl is covered by the proposed rule.

      Response:  Our intent is  that  the  rule only cover equipment
 used  to produce,  store,  and transfer liquid HCl product at a
plant site where the HCl production unit is located.  However,   we
 do not believe that  the commenter's  suggestion is the best
 approach  to clarify  this point.   In  the final rule, we have
 specified that the HCl production  facility ends at the point
where the HCl product leaves  the plant site via pipeline.   We
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believe that this makes it clear that "off-site" equipment is not
subject to the provisions of this rule.

     Comment:  Two commenters (IV-D-13, IV-D-14) requested that
relief vents,  sampling vents,  and rupture disks be specifically
exempted from the proposed rule.  The commenters referred to the
HON for an example of a definition of a relief valve  (§63.111)
and relief valve exemption (§63.107(h)(1)).

     Response:  We have exempted these types of equipment from the
final rule.

     Comment:  Two commenters (IV-D-13, IV-D-16) requested that
the proposed rule exempt transfer operations that perform vapor
balancing during all loading operations.  The commenters
explained that  vapor balancing means that vapors that are
displaced while a mobile vessel (e.g., tank truck,  railcar,  ship,
barge)  is being loaded are returned via  a vapor return line to
the tank from which the vessel is being  filled, thereby resulting
in the prevention of emissions.   The commenters cited the HON
(§63.100(f) (10))  as an example of a rule that provides such an
exemption.   Another commenter  (IV-D-22)  requested an exemption
for HC1 distribution performed by mobile transporters (e.g.,  tank
trucks,  railcars)  because such operations are generally vapor
balanced.

     Response:  In the final rule,  we have incorporated an
exemption for  transfer operations that are  vapor balanced,
provided that  they are vapor balanced to a  storage tank subject
to the rule.   This will ensure that the  emissions are controlled
because they are routed directly to a storage tank with emissions
controls.   This exemption is accomplished via the definition of
emission stream,  which states  that gaseous  streams from transfer
operations  that are vapor balanced to a  storage tank subject to
the rule are not emission streams,  and,  therefore,  not subject to
the emission limitations in the rule. We have also added a
definition  of  "vapor balanced,"  which is consistent with the
definition  in  the HON.

     However,  we do not believe it is necessary to exempt mobile
transporters,  as we have specified that  the HCl production
facility ends  at the point that the HCl  produced is loaded into a
tank truck, rail car,  ship,  or barge.

     Comment:  Several commenters (IV-D-09,  IV-D-12, IV-D-13,  IV-
D-14,  IV-D-15,  IV-D-17,  IV-D-18,  IV-D-19,  IV-D-22)  requested that
the EPA exempt  from the proposed rule storage tanks that are
smaller than a  certain capacity.   The commenters pointed out that
the potential  emissions from small storage tanks are low while
the control costs are very high.

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     One conunenter  (IV-D-09)  suggested a minimum capacity  of
 15,000 gallons  for  storage  tanks  subject to the proposed rule.
 Several commenters  (IV-D-12,  IV-D-15, IV-D-18) requested that
 storage tanks smaller  than  20,000 gallons capacity be exempted
 from the proposed rule.  One  comrnenter further requested an
 exemption for all portable  storage containers  (e.g., drums, tank
 trucks, railcars) .  Another commenter (IV-D-13) referred to
 several other rules  (40 CFR Subpart G, Table 5; 40 CFR  60.110(b))
 which exempt storage tanks  with a capacity less than 75 cubic
 meters (19,817  gallons) and all portable storage containers.
 Several commenters  (IV-D-14,  IV-D-17, IV-D-22) reiterated  a
 minimum capacity of 75 cubic  meters.  One commenter  (IV-D-19)
 suggested that  tank capacity  and HCl vapor pressure be  used
 together to determine which storage tanks should be exempt.

     Response:  We understand  the commenters' concern about the
 cost of controlling emissions from small storage tanks.  However,
 we believe that small storage tanks are not likely to be covered
 by the final rule given the other changes that we have made based
 on comments received.  We have exempted storage tanks that never
 store liquid HCl product with a concentration of 30 weight
 percent or greater  (see the next  comment in this section).  We
 have also defined the HCl production facility such that storage
 tanks that store HCl for use  in wastewater treatment or as
 feedstock for another process are not part of the HCl production
 facility (see section 2.1.2) .   Therefore, we have not added an
 exemption for small storage tanks.

     Comment:  Several commenters  (IV-D-12,  IV-D-13, IV-D-15, IV-
 D-18)  requested that the proposed rule exempt equipment (e.g.,
 absorbers,  storage tanks,  transfer operations) that contains HCl
 below the minimum concentration specified in the HCl production
 facility definition (see comments in section 2.1.1 regarding
 raising the minimum concentration).   The commenters noted that
 HCl solutions at low concentrations have low vapor pressures and,
 consequently,  low emissions.

     Response:  As discussed above in section 2.1.1, we have
 revised the applicability criteria to only include HCl production-
 facilities that produce liquid HCl product with a concentration
 of 30 percent by weight or  greater.   And we have specified that
 only storage tanks that contain,  and transfer operations that
 load,  this HCl product produced onsite in the HCl production unit
 are included in the HCl production facility.  In addition,  we
have added exemptions  [in §63.9000(c)] for storage tanks that
never contain liquid HCl product with a concentration of
 30 percent by weight or greater and transfer operations that
never load HCl product at that concentration.
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     Comment: Several commenters (IV-D-09, IV-D-13, IV-D-14,  IV-
D-15, IV-D-16, IV-D-22) requested that the proposed rule exempt
individual emission points  (e.g., absorbers,  storage tanks,
transfer operations) that emit less than a certain amount of  HAP
per year because they are costly to control and controlling them
contributes little environmental benefit.  One commenter
suggested that the proposed rule limit uncontrolled emissions
from the entire affected source to 1 Mg  (1.1  tons) per year.
Another commenter  (IV-D-13)  suggested that the proposed rule
exempt emissions points that emit less than 10 Mg  (11 tons) of
HAP per year.  Several commenters (IV-D-13, IV-D-14,  IV-D-15, IV-
D-16, IV-D-22 )suggested that the proposed rule follow the
example used in the HON (§63.113(c)) and exempt emission points
that emit less than 0.45 kilograms of HAP per hour.

     Response: We have changed the applicability criteria and
added exemptions to reduce the burden associated with requiring
controls on emission points  that have little  emission potential.
We do not believe an additional exemption based on emissions  is
practical,  as the burden to  demonstrate and document the emission
levels for these exempted points could approach or exceed the
costs of installing controls.   Therefore, no  such exemptions were
added to the final rule.

2.1.5     Once In, Always In

     Comment: Two commenters (IV-D-13,  IV-D-14)  requested that
the EPA reconsider its policy that,  once a facility is subject to
a MACT standard,  the applicability of that and any other relevant
MACT standards,  promulgated  presently or in the future,  cannot be
revoked.   The commenters requested that language be added to  the
applicability section of the proposed rule, or to the General
Provisions (40 CFR Part 63 Subpart A),  to allow facilities to
petition for removal of MACT applicability if a facility reduces
its potential-to-emit below  major source thresholds through
measures not required by any applicable standard  (e.g.,  process
modifications,  pollution prevention activities,  material
substitution,  or process refinements).   The commenters further
requested that the proposed  rule include language stating that
the major source status of a facility will be evaluated as of the
final promulgation date of the standard.

     Response: This is an issue that is much broader than this
rule.  It is being considered as part of the  General Provisions
rulemaking.   Therefore, it will not be addressed in this
rulemaking.
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 2.2   COMPLIANCE DATES

 2.2.1    Conflict with Electronic  Compliance

      Comment: Two commenters  (IV-D-12,  IV-D-13) stated  that  they
 will  not be able to meet  the  reporting  and  recordkeeping
 deadlines in the proposed HC1 rule  if the proposed  "Establishment
 of Electronic Reporting:  Electronic Records" rule  (proposed  at  66
 FR 46162) is promulgated.  The commenters estimated that  it  would
 take  them at least 10 years to develop  and  deploy computer
 systems capable of maintaining the  records  required under the
 proposed electronic records rule.   The  commenters therefore
 requested that, if the electronic records rule is promulgated,
 the final HCl production  rule extend the dates for submitting
 applications, notifications, and reports by at least 10 years.

      Response:  If the proposed electronic reporting and
 recordkeeping rule is promulgated,  electronic reporting and
 recordkeeping will remain "purely voluntary."  The proposal
 preamble for the electronic records rule further states that the
 proposed electronic records rule would  not  amend any existing
 compliance requirements or affect whether documents need to  be
 created, submitted,  or retained under existing rules in Title 40
 of the CFR.   Facilities that wish to convert to electronic
 reporting and recordkeeping can continue to retain and submit
 records and reports in paper format until they develop adequate
 computer systems.   Therefore,  we have not changed the compliance
 dates in the final HCl rule, because the proposed electronic
 records rule does not provide a valid reason for suspending
 compliance requirements until facilities can develop appropriate
 computer systems capable of retaining and submitting electronic
 records and reports .

 2.2.2     Specific Compliance Extension

     Comment: One commenter (IV-D-11) asked for verification that
 the six-year compliance extension granted to one of his company's
 facilities would apply to the HCl production rule.  The facility
was granted the extension for participating in the Early
Reduction Program (40 CFR Subpart D).   The  commenter assumed that
 the facility would not have to perform  the  initial performance
 test or submit  any notifications, other than the Initial
Notification,  until nine years after the promulgation date of
this rule (the  6-year extension plus the three years between
promulgation and the compliance date as specified in the rule).

     Response:  According to section  112(i)(5)  of the Clean Air
Act,  an existing source that achieves a HAP emission reduction of
90 percent or more for gaseous HAP  or 95 percent or more for
particulate  HAP before an applicable standard is proposed shall

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 be  issued  a permit allowing the source to meet an alternative
 emission limitation for a period of six years from the compliance
 date  for the otherwise applicable standard.  The alternative
 limits and other terms and conditions must be put in a Title V
 permit as  specified in 40 CFR subpart D.  Sections 63.6(i) (2)
 (General Provisions) and 63.72  (Subpart D) implement this
 compliance extension for the Early Reduction Program.  Assuming
 the commenter achieved the reduction before the HCl production
 MACT  rule  was proposed and they have been granted a 6-year
 extension  in a Title V permit, the commenter's assumption appears
 to be consistent with the Clean Air Act provisions.   However, a
 site-specific decision for the commenter's facility with respect
 to this rule will need to be made by the Administrator,  or the
 delegated  authority, after this rule is promulgated.  In
 addition,  the facility's compliance obligations under this rule
 will  need  to be included in the facility's Title V permit in
 accordance with Title V and 40 CFR Parts 70 or 71,  as
 appropriate.

 2.3   DEFINITIONS

 2.3.1     Hydrochloric Acid Process Vent

      Comment:  Several commenters (IV-D-12,  IV-D-13,  IV-D-16)
 requested  that the definition of "hydrochloric acid process vent"
 be clarified to indicate which vents are subject to the proposed
 rule because the proposed definition does  not specify the
 equipment or process(es)  from which such a vent originates.  They
 also  requested that a definition of "process vent"  be added to
 the rule because the term is used in the "hydrochloric acid
process vent"  definition but not defined.   The commenters
provided suggested rule language both clarifying what a
hydrochloric acid process vent is (e.g.,  a gas stream exiting a
water scrubber/absorber)  and defining what a process vent is
 (e.g., point of discharge to the atmosphere of a gas stream) and
 is not (e.g. ,  relief valve discharge,  etc.) .

     Response:  First,  we have changed the  term from "hydrochloric
acid process vent"  to "HCl process vent" in the final rule to be
consistent with the language in the affected source definition in
 §63.8990.  We agree with the commenters that the definition of
 "hydrochloric acid process vent" could be  more specific to
 indicate the parts of the process or unit  operations from which
 an HCl process vent originates.   Based on  the available
 information,  all of the hydrochloric acid  process vents originate
 from an HCl absorber in which the liquid HCl product is produced
 (the  "HCl production unit").   Therefore,  in the final rule, we
have  specified that a HCl  process vent originates from an "HCl
production unit," which we have defined in the final rule  (see
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 response  to  comment  in  section  2.1.1 regarding  the  definition of
 "HCl production  facility").

     While we  agree  with the concepts  in  the  definition  of
 process vent cited by the commenters,  we  decided  to incorporate
 these general  concepts  into the definition of HCl process vent,
 rather than having a separate definition.  Therefore,  the
 definition of  HCl process vent  indicates  that it  is a  point  of
 discharge to the atmosphere or  the point  of entry into a control
 device of a gas  stream  and listing several things that are not
 process vents.

     Following is the definition of "HCl  process vent" in the
 final rule:

          HCl process vent means the point of discharge  to
          the  atmosphere, or point of  entry into a  control
          device, of a  gaseous stream  that originates  from
          an HCl production unit.  The following points  of
          discharge  are not HCl process vents:
          (1)  A leak from equipment in HCl service
          subject to this subpart.
          (2)  An exit  from a control device used to comply
          with this  subpart.
          (3)  An HCl storage tank vent or HCl  transfer
          operation  vent subject to this  subpart.
          (4)  A HCl wastewater operation vent  subject to
          this subpart.
          (5)  A point  of discharge from  a relief
          valve.
          (6)  A point  of discharge from  an analyzer.

2.3.2     HC1/C1; Service

     Comment: Several commenters (IV-D-07, IV-D-12,   IV-D-13,  IV-
D-19)  requested that the definition of "in HC1/C12 service"  be
revised so that only equipment containing a certain minimum
amount of HCl or C12  is  included.   The  commenters noted that, as
written,  the definition of "in HC1/C12  service," which is used to
indicate which equipment must be included in a  leak detection and
repair (LDAR) plan,   seems to include any  equipment  that  contains
even trace amounts of HCl and chlorine, which could greatly
increase the burden  for sources to inspect this equipment and
keep records of the  inspections with minimal emission  reduction.
The commenters suggested several minimum  levels including: one
percent,  because this is the minimum HCl  or C12  concentration
reported on Material Safety Data Sheets (MSDS);  10  percent;  and
31.45 percent,  based on comments (see section 2.1.1) that this
should be the minimum HCl concentration for an  HCl  production
facility.

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     One coiraienter  (IV-D-19) suggested that the EPA separate  the
 existing definition into one definition for "in chlorine service"
 and one definition for "in HCl service."  For the definition  of
 "in chlorine service," the commenter suggested that the EPA adopt
 the concept used in the HON to define "in organic HAP service"
 (§63.161), which sets a lower limit of five percent by weight.
 For the definition of "in HCl service," the commenter suggested
 that 22 percent by weight be used as the lower limit because
 liquid HCl at a concentration of less than 22 percent by weight
 has a vapor pressure lower than 500 ppmv,  which is the value  used
 in other NESHAP to define the minimum concentration for equipment
 to be considered "leaking."  The commenter reasoned that
 equipment containing less than 22 percent HCl by weight does  not
 have the potential to be "leaking equipment" and should,
 therefore, not be included in the LDAR plan.

     Response:  First,  as a result of other comments related to
 how the term "equipment" was used,  the term "in HC1/C12  service"
 has been replaced with "Equipment in HCl service" (see section
 2.3.8) .

     We agree with the commenters that a minimum HCl level should
 be specified for equipment "in HC1/C12  service."   In  considering
 the suggestion to separate the HCl  service and C12  service
 definitions,  we concluded that only a definition of "in HCl
 service" is needed.   A definition of "in C12 service"  is
 unnecessary because any equipment at an HCl production facility
 that contains C12 would  also  contain HCl.

     We have decided to establish separate minimum levels for
 liquid and gaseous HCl because leaking equipment containing
gaseous HCl will leak gaseous HCl at the same concentration as
 that of the gas in the equipment, whereas  equipment containing
 liquid HCl will leak gaseous HCl at the concentration of the  gas
 in equilibrium with the liquid HCl.  In the final rule,  we define
 the minimum liquid HCl level as 30  percent by weight,  to be
consistent with the minimum liquid  HCl  concentration that defines
an "HCl production facility" (see response to comment in section
2.1.1 regarding the minimum HCl concentration).   We considered
defining the minimum gaseous HCl level  as  the percent by weight
of gaseous HCl  in equilibrium with  liquid HCl at 30 percent by
weight,  which is approximately 3.4  percent by weight at 30°C.   We
chose to define the minimum gaseous HCl level as 5 percent by
weight to approximate the concentration in equilibrium with 30
percent liquid HCl by weight and to be consistent with the HON
and other rules.  The revised definition also reflects the fact
 that equipment  is considered to be  "in HCl service" if it ever
contains greater than or equal to 30 percent liquid HCl by weight
or 5 percent gaseous HCl by weight.
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 2.3.3      Caustic  Scrubber

     Comment:  Several  commenters  (IV-D-12,  IV-D-13,  IV-D-16)
 requested  that the definition  of  "caustic scrubber"  be  modified
 to  reflect  the fact  that  sodium hydroxide,  not  lime  or  limestone,
 is  the most common caustic  substance  used.  One commenter  (IV-D-
 12) recommended that "sodium hydroxide" be  added  to  the
 parenthetical  list of  caustic  solutions in  the  definition.
 Another commenter  (IV-D-13) stated  that the inclusion of specific
 examples of caustic  substances is unnecessary;  the commenter  also
 stated that caustic  scrubbers  are most often employed to control
 chlorine emissions.

     Response:  We  agree with the commenters' suggestions and  have
 removed the reference  to  specific caustic substances.   We have
 also added a reference to the  control of chlorine.   Finally,  to
 be  consistent  with our response to  the comment  in section 2.3.5
 regarding the  definition  of water scrubber/absorber, we have
 changed the term to  "caustic scrubber control device."  Following
 is  the definition  of "caustic  scrubber control device"  in the
 final rule:

          Caustic  scrubber control  device means any
          add-on device that mixes  an aqueous stream or
          slurry containing a  caustic substance with
          the  exhaust gases from an HCl  process vent,
          HCl  storage tank,  or  HCl  transfer operation
          to control emissions  of HCl and/or chlorine.

 2.3.4     Deviation

     Comment:  The proposed rule defines a "deviation" as any
 instance in which  an affected  source fails to meet any  (1)
 requirement established by this subpart,  (2) term or condition
 included in the operating permit to implement any requirement in
 this subpart,  or (3)  emission  limitation in this subpart during a
 startup,  shutdown,  and malfunction  (SSM)  event.   Two commenters
 (IV-D-12,  IV-D-13)  requested that the EPA delete item (2) from
 the definition.  The commenters argued that including this
provision appears to extend the definition of deviation, and
 consequently the reporting requirements for deviations,  to
 requirements imposed under Title V of the Clean Air Act  (e.g.,
 specified in a source's Title V permit).   The commenters noted
 that Title III of the Clean Air Act, which authorizes the
proposed rule,  does not provide the EPA with the authority to
 enforce compliance with requirements specifically established
under Title V.

     One commenter (IV-D-12) further requested that the term
 "excursion" be used instead of  "deviation" in the proposed rule

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 because  "deviation" already has a specific connotation under
 Title V.

     Response: We reject the commenters' request to delete  item
 (2) from the proposed definition of the term "deviation."   Item
 (2) is necessary to ensure that failures to comply with terms  and
 conditions of Title V operating permits which implement the
 applicable requirements of this subpart are reported as
 deviations under this subpart.   Title V and EPA's implementing
 regulations codified at 40 C.F.R. Part 70 require every major
 source  (and certain other sources) to obtain an operating permit
 that assures compliance with each applicable standard, regulation
 or requirement (commonly known as "applicable requirements")
 under the CAA (CAA §§502 (b) (5) (A) , 504 (a) ;  40 CFR §70 . 6 (a) (1) ) .
 For sources subject to this subpart,  the requirements of this
 subpart will be "applicable requirements"  for purposes of Title V
 (40 CFR §70.2 defines "applicable requirement" to include any
 standard or other requirement under CAA §112).    Accordingly,
 those sources' Title V operating permits must assure compliance
with the requirements of this subpart.  It  follows that this
subpart must define deviations  to include  failures to meet
operating permit terms and conditions that  are adopted to assure
compliance with this subpart.

     This subpart does not change sources'  reporting obligations
or EPA's enforcement .authority under Title  V.   However,  this
subpart does allow sources to coordinate the submittal of the
deviation reports required under this subpart with the semiannual
monitoring reports required under Title V.   Section 63.9050(b)(5)
provides that where a Title V permitting authority has
established dates for submitting semiannual monitoring reports
required under 40 CFR §§70.6(a) (3) (iii) (A)  or 71.6(a)  (3) (iii) (A) ,
affected sources that are subject to Title  V permitting may
submit the compliance reports required under this subpart
according to the dates established by the  permitting authority
instead of the dates established in this subpart.

     We also reject the request that the term "excursion" be used
instead of the term "deviation."   Use of the broader term
"deviation" is consistent with  other CAA requirements such as
Title V reporting requirements  and must be  consistent to-
facilitate coordinated implementation, such as coordinated
deviation reporting.   Any excursion from an emission limitation
or work practice standard is  a  deviation,  regardless of whether
such excursion is specifically  excused or  occurs when the
emission limitation or work practice standard does not apply,
such as during periods of startup,  shutdown,  or malfunction.   To
clarify the meaning of the term "deviation," however,  we are
adding a reference to any "work practice standard" in order to
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make clear  that  the  term applies  to the site-specific LDAR
program  requirements of this subpart.

2.3.5     Water  Scrubber/Absorber

     Comment: Several commenters  (IV-D-13, IV-D-16) requested
that the definition  of "water scrubber/absorber" be revised  to
reflect  the  fact that water scrubbers do not neutralize HCl  and
that, in the context of the proposed rule, they are used to
control  emissions and not to absorb HCl.

     Response: We agree that the definition of "water
scrubber/absorber" should be modified to clarify that they do not
neutralize HCl, because they do not use caustic substances.  In
response to  the comment that water scrubber/absorbers are not
used to absorb HCl, we note that the devices used to produce HCl
through absorption into water or dilute hydrochloric acid are
very similar (even identical)  to the devices that are sometimes
used to control emissions from HCl production facility emission
points.  In  the final rule,  we have changed the term "water
scrubber/absorber" to "water scrubber control device" which
specifies that it is used to control emissions from an HCl
process vent, HCl storage tank,  or HCl transfer operation.
Additionally, we have added a definition of "HCl production unit"
which specifies that water absorbers are used to produce HCl
through absorption into water or dilute HCl (see response to
comment in section 2.1.1 regarding the HCl production facility
definition).  Following is the definition of "water scrubber
control device" in the final rule:

          Water scrubber control device means any add-
          on device that mixes an aqueous stream not
          containing a caustic substance with the
          exhaust gases from an HCl process vent,  HCl
          storage tank,  or HCl transfer operation to
          control emissions of HCl and/or chlorine.

2.3.6     Transfer Operations

     Comment: Two commenters (IV-D-13,  IV-D-19)  requested that
the definitions of "transfer (or loading)  rack"  and "transfer
operation"  be amended to clarify that only operations
transferring HCl above the minimum HCl concentration specified
for an HCl  production facility are affected.

     Response:  First, we have changed the term from "transfer
operation"  to "HCl transfer operation"  in the final rule to be
consistent  with the language in the affected source definition in
§63.8990.  We agree with the commenters' point that transfer
operations  transferring liquid HCl that is more  dilute than  the

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 minimum  concentration in the applicability criteria should not  be
 subject  to  the rule.  Therefore, §63.9000(c) (3) exempts HCl
 transfer operations that never load liquid HCl product with  a
 concentration of 30 percent by weight or greater.  Furthermore,
 we have  added a clarification to the "HCl transfer operation"
 definition  that only those transfer operations for which HCl is
 the predominant use are considered "HCl transfer operations."
 Predominant use is defined within the "HCl transfer operation"
 definition  as the material that is loaded by the transfer rack  in
 the greatest amount.

 2.3.7     Storage Tanks

     Comment:  Two commenters (IV-D-13,  IV-D-16) requested that
 the EPA  add a definition of "HCl storage tank" to the proposed
 rule in  order to clarify which storage tanks are affected.  The
 commenters  suggested that the def-inition include: a minimum size
 (10,000  gallons,  75 cubic meters),  a minimum concentration of HCl
 stored in the tank (10 percent),  and a list of things that are
 not storage tanks (e.g.,  vessels permanently attached to mobile
 vehicles, bottoms receiver tanks,  surge control vessels, and
 wastewater  storage tanks).

     Response:  We agree with the commenters and have added a
 definition of "HCl storage tank" to the rule.  The definition
 specifies that vessels permanently attached to vehicles and
 wastewater storage tanks are not HCl storage tanks.  We have
 chosen to include bottoms receiver tanks and surge control
 vessels  as HCl storage tanks because the control requirements do
 not necessitate a distinction between storage tanks and bottoms
 receiver tanks and surge control vessels.

     We  believe that tanks that only store dilute HCl product
produced in the HCl production unit should be considered part of
 the HCl  production facility and the affected source,  but should
not be subject to the emission limitations.   An exemption for
 such storage tanks is provided in §63.9000 (c) of the final rule.
We also believe that small storage tanks that store liquid HCl
product produced on-site in the HCl production unit should be
considered part of the affected source.   However, we believe that
most small storage tanks are unlikely to be subject t.o the rule
because  of the exemptions for wastewater tanks, feedstock tanks,
 tanks attached to vehicles,  and tanks storing dilute HCl.
Therefore,  the definition does not include a minimum size.

 2.3.8     Equipment

     Comment:  One commenter (IV-D-16)  stated that the word
 "equipment" seems be used to mean several things in the proposal
preamble and proposed rule.   The commenter stated that the

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 meanings of the word  in proposed  §63.8985(a)(1) and
 §63.8990(b)(4) are confusing.  The commenter suggested that  the
 EPA include a definition of  "equipment"  in  the proposed rule and
 make it clear when the use of this meaning  is intended.

     Response: We agree with the  commenter  that using the  term
 "equipment" in different contexts could  cause confusion.   We have
 added a definition of "equipment  in HCl  service" to the rule to
 apply specifically to the "equipment" mentioned in proposed
 §63.8990(b)(4) that is to be covered  by  the equipment leak plan.
 Also,  see the response related to the proposed definition  of "In
 HC1/C12  service"  in section  2.3.2.

     To clarify the meaning of "equipment"  in the definition of
 an HCl production facility in proposed §63.8985(a) (1) ,  we  have
 revised the definition of "HCl production facility" to include
 "unit operations and associated equipment"  instead of "equipment"
 (see response to comments in section  2.1.1) .

 2.4  MACT DETERMINATIONS

 2.4.1     Basis for MACT Standard

     Comment:  Many commenters (IV-D-09,  IV-D-13, IV-D-14,   IV-D-
 15,  IV-D-16, IV-D-17,  IV-D-18,  IV-D-22)  stated that the EPA  did
 not use data that was truly representative of the sources  in the
 source category when determining the  MACT emission limitations.
 The commenters believed that the database used to prepare  the
 proposed rule contained facilities that would not be subject to
 the proposed rule and did not contain many facilities that would
 be subject to the proposed rule.   One commenter (IV-D-17)   stated
 that the universe of sources subject  to  the proposed rule  is
 likely to be around 200 to 300,  rather than the 64 facilities
 that the EPA identified as potentially subject.  A trade
 organization  (IV-D-13) stated that the universe of sources
 subject to the proposed rule is likely to be much greater  than
 the 64 sources that the EPA identified as potentially subject.
Many companies that are members of the commenter's organization
 operate HCl production facilities which were not included  in the
 EPA's  list of 64 potentially subject  sources or in the database
 of 31  facilities that the EPA used to establish the MACT floor.
 Some commenters provided specific examples of this
 inclusion/exclusion.   Commenter IV-D-16 noted that the company
 operates HCl production units at three major source plant  sites
which  were not appropriately represented in the database.   One of
 these  sites was listed as potentially subject facility, along
with another site owned by the company that is not a major source
 site.   Information for one HCl production unit  (associated with
 fumed  silica production)  at the major source site was included in
 the MACT database.   Therefore,  two major source sites were not

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 included in the list of 64 potentially subject facilities.
 Further, there are four HC1 production units at these two sites,
 and two additional units at the site where fumed silica is
 produced, that were not represented in the MACT database.
 Therefore,  this commenter points out that the EPA's MACT floor
 database did not contain information regarding six of the
 commenter's company's seven HC1 production units.   Commenter IV-
 D-06 noted two instances of plants listed as owned by their
 company that should be removed from the list (the company no
 longer owned a plant at one location listed and another one had
 been dismantled).   Another commenter (IV-D-18)  stated that many
 of the facilities included in the database are currently
 regulated,  or will be regulated,  by other MACT standards and are,
 therefore,  not part of the HC1 production source category.
 Commenter IV-D-09 also pointed out several detailed errors
 related to a facility owned by the commenter's company in the
 EPA's database.

     Commenter IV-D-15 maintained that this lack of
 representativeness of the source category resulted in proposed
 emission limitations that were not adequately justified for the
 HCl production source category.  Another commenter believed that
 the use of  more representative data could change the MACT
 determination  (IV-D-13).   Commenter IV-D-14 believed that the EPA
 should withdraw the proposed rule and re-propose it after
 properly surveying the industry and re-calculating the MACT floor
 based on accurate data.

     Two of the commenters (IV-D-14,  IV-D-18)  specifically
 requested that EPA gather data, including control  device
 characterization and stack test data,  from a more  representative
 group of potentially affected facilities using its authority
 under §114  of the Clean Air Act and use the data to re-calculate
 the MACT floor.  Several of the commenters offered to provide
 additional  information.

     Commenter IV-D-18 expressed the belief that accurate data
would show that a MACT standard is not necessary for this source
 category because the small emission reduction is not worth the
 large associated cost.

     In addition to comments related to how well the EPA database
 represents  the HCl production source category,  one commenter (IV-
 D-15)  questioned the use of information from "hollow" Title V
 permit applications.

     Response: First, we will review the process used to obtain
 the information for the HCl production source category,  followed
 by responses to the specific issues raised by the commenters.
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      In  creating  our  list  of  sources  in  the HCl production source
 category, we  consulted  the Chemical Economics Handbook1  (CEH),  a
 very  reliable and well-respected  source  of information  on the
 chemical  industry.  We  recognized the  special difficulty in
 identifying all HCl production  facilities, since HCl  is often
 produced  from by-product streams  only  for internal uses,  and
 considered that this  CEH list may not  be a comprehensive list  of
 facilities that could be subject  to the  proposed rule.
 Therefore, during a February  28,  2001  meeting with the  American
 Chemistry Council (Commenter  IV-D-13)  and member company
 representatives,  we specifically  requested assistance in
 improving our list of facilities  created from the CEH.2  However,
 no additional information  resulted from  this request  for
 assistance.

      The  CEH  listed 86  plant  sites where HCl is produced.   As
 pointed out by commenters,  it is  possible that HAP emissions from
 HCl production facilities  could be covered by another MACT
 standard, and we  attempted to identify such sources in  the CEH
 list  and  remove them  from  our list of  facilities in the source
 category.3  Specifically,  we removed facilities  that  we believed
 could be  subject  to NESHAP  for the following source categories:
 chlorine  production,  steel  pickling -  HCl process,  primary
 magnesium, and pesticide active ingredient.  We also removed
 facilities that were noted to produce  HCl via the combustion of
 chlorinated organic compounds.  This left 61 plant sites.   We
 then added three  more plant sites  that we were made aware  of
 through contacts  with State agencies,  for a total of 64  sites.

     The  applicability  provisions  of the proposed HCl production
NESHAP,  especially those aspects  related to potential overlaps
with other NESHAP, are  quite difficult to apply without
considerable  information about each facility.   The complexity  is
 further increased by the fact that several of the NESHAP with
potential overlaps have yet to be proposed.  Actual site-specific
applicability determinations will need to be made by each
     1   Byth,  W.A.,  Leder,  A.,  and Takei,  N.   CEH Marketing
Research Report: Hydrochloric Acid.  SRI International.  December
1998.

     2   Memorandum.   Friedman,  B.,  EC/R Incorporated,  to Maxwell,
B., EPA/CG.  Summary of Meeting with American Chemistry Council.
March 8, 2001.  (Docket Item II-E-2}

     1   Memorandum.   Maxwell,  B.,  EPA/OAQPS/ESD,  to  Hydrochloric
Acid Production NESHAP Docket.  List of Facilities in the
Hydrochloric Acid Production Source Category.  March 21, 2001.
{Docket Item II-B-7}

                               2-34

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owner/operator and the appropriate regulatory agency after these
NESHAP are finalized.

     While commenters claim that there could be potentially two
or three times more facilities subject to the HCl production
NESHAP than we originally estimated,  there was little substantial
information provided to support this  claim.   There were two sites
on the list that Commenter IV-D-06 said should be removed.
Commenter IV-D-18 reported that all of the HCl production
processes located at one site would be subject to other MACT
standards,  and should not be included in the HCl production
source category.  Commenter IV-D-16 alluded to the fact that one
plant site listed for their company was an area source,  and that
two additional sites that are major sources where HCl is produced
did not appear on the list.  One of these missing sites was on
the original CEH list but was removed because HCl production was
identified as being associated with a chlor-alkali plant.  Since
the commenter did not provide the location of the final facility,
we were unable to add it to the list  of potentially subject
facilities.  Therefore,  there were no HCl production plant sites
specifically mentioned (i.e.,  a plant name/site location
provided) by commenters that were not on the list of 64
potentially subject facilities.

     We removed the three facilities  from the list noted by
Commenters IV-D-06 and IV-D-18.  In addition, we realized that
four additional facilities that were  identified as HCl producers
through contacts with State agencies  prior to proposal were
inadvertently left off the list.   Therefore,  the updated list of
potentially subject facilities contains 65 plant sites.

     As was documented in several items in the docket,  our
information gathering approach for this source category was to
obtain available information from State/Local agencies in States
where HCl production facilities are located.   Specifically, we
obtained information during a visit to the Louisiana Department
of Environmental Quality offices for  12 plant sites in Louisiana,
and we requested information from every other State agency where
four or more HCl production facilities are located (based on the
CEH list prior to the removal of facilities).4   This  resulted in
data for 24 HCl production units at 19 plant sites in 5 States .
In addition,  we had information from site visits to 6 additional
HCl production units at 5 more plant  sites,  meaning that the MACT
database contained information representing 30 HCl production
     4   Memorandum.   Seaman,  J.  and Norwood,  P.   EC/R
Incorporated, to Wood,  J.,  EPA/OAQPS/ESD/MICG.   Request to State
Agencies for Title V Permit Applications.  November  16, 1999.
{Docket Item II-B-1}

                               2-35

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 units at 24 plant sites in 9 States.  We believe that this was  a
 reasonable approach to obtain information for this industry.

     Some commenters requested that we distribute a questionnaire
 under our section 114 authority to "accurately reflect the source
 category."  However, the commenters did not provide a list of
 plants to whom this questionnaire should be sent to ensure that
 the data were more representative than the data set we obtained
 from State agency files.  Some commenters, however,  did offer to
 provide additional information for their HCl production units,
 which could have resulted in data for a few additional processes.
 However, we concluded that the original data set was adequate to
 determine MACT and did not feel it was necessary to burden the
 industry with a data collection request.

     One commenter objected to the use of data from "hollow"
 Title V permit applications.   These applications contained
 process information, control device information,  and emissions
 information that we believe was adequate to use in determining
 MACT.  Further,  unless proven otherwise, we will continue to
 operate under the assumption that data provided by companies and
 certified by their responsible officials in Title V permit
 applications are truthful,  accurate and complete representations
 of the emissions and controls and that such data are appropriate
 to consider in determining MACT.

     Commenters also complained that many of the plants
 considered in the MACT floor analysis were actually plants that
 are not in the source category.   These commenters are correct,  in
part,  in that we did utilize data from two plants that we have
 removed from the CEH list because we presumed that these HCl
production processes were,  or would be,  subject to another MACT
 standard.   To eliminate this inconsistency,  we have removed these
 two facilities from the MACT analysis.  As noted above,  Commenter
 IV-D-18 provided information that indicated that all HCl
production processes at one of their facilities were,  or would
be, subject to other MACT standards.   This facility,  which was
one that was included in the MACT floor determination at
proposal,  was also removed from the MACT floor analysis.  Two
commenters (IV-D-09 and IV-D-18)  pointed out that the data used
 in the floor analysis for two facilities were for related
processes at the site that would not be subject to the rule.
These were also removed from the analysis.  Finally,  we
recognized that one of the facilities appeared twice in the
database,  once based on information that was obtained during a
site visit (it was listed as  a CBI facility in the MACT floor
analysis prior to proposal),  and once based on information that
was provided by a State agency.   Since the State data were more
complete,  we removed the other occurrence from the database.
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 Therefore, the revised MACT floor analysis is based on facilities
 that, to  the best of our knowledge, are in the source category.

     While we did not agree with the commenters regarding the
 representativeness and adequacy of our MACT database, and we did
 not undertake an additional data gathering effort after proposal,
 we did revise our MACT analysis to address many of the other
 issues raised by commenters regarding the determination of the
 emission  limitations.  Specifically,  we would point out changes
 in the methods for determining the MACT floor, alternative
 emission  limitations (including the determination of the
 alternative concentration limitation),  and the assumptions
 regarding common control devices in the impacts analysis.  These
 are discussed in the following sections.

 2.4.2     Determination of MACT Floor

     Comment:  One commenter (IV-D-13)  challenged the EPA's
 application of the requirement in §112 (d) (3)  of the Clean Air Act
 to set the MACT floor based on the average emission limitation
 already being achieved by the best-performing 12 percent of the
 existing sources (or the best-performing 5 sources for categories
 or subcategories with fewer than 30 sources).   The commenter
 stated that the EPA should have based the floor calculation on
 the top 12 percent of the sources rather than on the top 5
 sources because it used data for 31 sources and estimated that  -
 there are 64 sources in the source category.   Additionally,  the
 commenter stated that the EPA should have calculated the floor
 using the average of the top facilities rather than the median.

     Response:  As noted above,  we currently estimate that there
 are 65 sources in the source category.   Therefore,  if data were
 available for all sources,  the MACT floor would be based on the
 best-performing 12 percent,  or 8 sources.   In our re-analysis of
 the MACT floor,  we considered the control achieved by the best-
performing 8 sources in our database,  which contains information
 on 20 facilities.

     We disagree with the commenter's  opinion regarding use of
 the average rather than the median.   As was stated in the
preamble for the proposed rule (66 FR 48180),  we have determined
 that "average"  means any measure of central tendency, whether it
be the arithmetic mean,  median, or mode, or some other measure
based on the central tendency of a data set.   We continue to
believe that this determination,  which  we originally published
 over eight years ago (June 6,  1994,  59  FR 29196),  is sound.   For
 the MACT determination for this source  category,  which was in the
 format of a percent emission reduction,  we determined that
 selection of the median value was most  appropriate.  This ensured
 that a control efficiency actually being achieved was selected,

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 rather than  the mean  of values, which would not likely have
 represented  the actual performance of an actual control device.

     Comment: Two commenters  (IV-D-13, IV-D-14) disagreed with
 how control  efficiencies reported as >99 percent were used in the
 MACT analysis.  Specifically, they stated that the EPA
 established  the MACT  floor for transfer operations using
 reasoning that was inconsistent with that used to establish  the
 MACT floor for process vents and storage tanks.  The commenters
 pointed out  that the  EPA disregarded data points listed as
 "greater than 99 percent removal efficiency" when establishing
 the MACT floor for process vents and storage tanks, but included
 such values  for transfer operations.  The commenters stated  that,
 using reasoning consistent with that used for process vents  and
 storage tanks, the MACT floor for transfer operations should be
 zero percent removal  efficiency because the only data point  that
 the EPA has  for transfer operations other than two "greater  than
 99 percent" values was zero percent.  One commenter (IV-D-13)
 requested that the EPA either set the MACT floor at zero percent,
 or at 66 percent,  which would be the mean of the three data
 points.   The other commenter  (IV-D-14) requested that the EPA set
 the MACT floor at zero percent and eliminate all of the testing,
 monitoring,  reporting, and recordkeeping requirements for
 transfer operations.

     Commenter IV-D-13 further stated that,  when the EPA
 disregarded data from top facilities because their control
 efficiencies were listed as greater than 99 percent rather than
 as specific numerical control efficiencies,  the EPA should have
 supplemented the data set of "top facilities" using the next best
 performing sources.   For example,  if the EPA had used the top 5
 process  vents, not including those listed as greater than 99
 percent,  the median would have been 99 percent rather than 99.4
 per.cent.

     Response: These commenters are correct in that we were
 inconsistent in how we considered facilities that reported
 control  efficiencies as >99 percent.  In evaluating this issue,
we determined that it was inappropriate to have not considered
 some of  the most effective controls in the source category for
process  vents and storage tanks simply because their efficiencies
were reported as "greater than" a particular number.   Therefore,
 in our re-analysis of the MACT floor,  we assigned a numerical
value of 99 percent emission reduction to each control device
 that reported an efficiency of > 99 percent or >. 99 percent.  The
data points reported as > 99 percent or >. 99 percent were
obtained from permit applications and we had no data that
 indicated more specific control efficiencies in these cases.   We
believe  that rounding these data points down to 99 percent
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 represents the closest actual control efficiency that we are  sure
 these sources could consistently meet.

 2.4.3     Re-Evaluation of MA.CT Floor

     As discussed above,  commenters had several issues with both
 the data considered in the MACT floor analysis and aspects of  the
 MACT determination approach.  As pointed out above in our
 responses to these issues,  we addressed many of these comments,
 which resulted in the need to re-evaluate the MACT floor.
 Following is a summary of the updated MACT floor analysis based
 on the revised data set and modified approach.  As a reminder,
 the MACT floor addressed HC1 emissions from process vents,
 storage tanks,  and transfer operations,  and chlorine emissions
 from process vents.   Further,  the format of the MACT floor for
 all emission sources is a percent reduction.  For process vents,
 Table 2-1 shows the control efficiencies for HC1 emissions and
 Table 2-2 shows them for chlorine emissions.  The control
 efficiencies for storage tanks and transfer operations are shown
 in Tables 2-3 and 2-4,  respectively.

     In our re-evaluation,  we determined the MACT floor for
 existing sources as the median value of the top eight facilities
 in the data set for each type of emission source.   For HCl
 emissions from process vents,  the highest 8 control efficiencies
 are 99.4 percent,  99.4 percent,  >99 percent, >99 percent,
 99 percent,  99  percent,  99  percent,  and 99 percent.  For the
values reported as >99 percent,  we simply assumed 99 percent.
 The median of these 8,  which is the MACT floor for existing
 sources,  is 99  percent.

     For chlorine emissions from process vents,  the highest 8
 control efficiencies are 99.8 percent, 99.4 percent,
 >99 percent,  >99 percent,  >99 percent, 99 percent,  99 percent,
and 99 percent.   Assigning  99 for those facilities reporting
>99 percent,  the MACT floor for existing sources is 99 percent.

     For HCl emissions from storage tanks,  the highest 8 control
efficiencies are 99.9 percent, 99.85 percent,  >99 percent,
 99 percent,  98  percent,  95  percent,  90 percent,  and 90 percent.
The median value,  then,  is  98.5 percent.

     There are only 2 control efficiencies for HCl emissions  from
 transfer operations,  both reported as >99 percent.   Assigning  99
 for these plants,  the MACT  floor for existing sources is 99
percent.

     Therefore,  the revised MACT floors for existing sources  are
 99 percent emission reduction for HCl emissions from process
vents and transfer operations, 99 percent for chlorine emissions

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from process vents,  and 98.5 percent for HC1 emissions from
storage tanks.  For consistency, we believe it is appropriate to
round the storage tank value to 99 percent.

     The revised MACT floors for new sources are 99.4 percent
emission reduction for HC1 emissions from process vents,  99.8
percent emission reduction for C12  emissions  from process  vents,
99.9 percent emission reduction for HCl emissions from storage
tanks,  and 99 percent emission reduction for HCl emissions from
transfer operations.   These new source MACT floors  are based on
the level of control  achieved by the best controlled source in
the category.
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Table 2-1.   Process Vent HCl Controls,
Company
Dow Chemical Co .
CBI Facility C
Louisiana Pigment
Co.
Formosa Plastics
Corp.
Bayer Corp .
Georgia Gulf
E.I. DuPont de
Nemours
DuPont Co .
Degussa Corp.
Allied Signal
Dow Chemical
DuPont Dow
Elastomers
CBI Facility E
CBI Facility A
Shell Oil Co.
CBI Facility B
Location
Plaquemine, LA

Westlake, LA
Pt. Comfort, TX
New
Martinsville , WV
Plaquemine, LA
Parkersburg, WV
LaPlace, LA
Waterford, NY
Baton Rouge, LA
Plaquemine, LA
LaPlace, LA


Norco, LA

Control
Device (s)
Gas scrubber
2 Caustic
scrubbers
Gas scrubber
Caustic
scrubber
Water
scrubber
Wet scrubber
Wet scrubber
Wet scrubber
Wet scrubber
Venturi
scrubber
Wet scrubber
Wet scrubber
Caustic
scrubber
none
Scrubber
Caustic
scrubber
Control
Efficiency
(percent)
99 .4
99 .4
>99
>99
99
99
99
99
99
99
>95
95
83 .3
0
not given
not given
                 2-41

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Table 2-2.  Process Vent Chlorine Controls.
Company
CBI Facility E
Dow Chemical
Louisiana Pigment
Co.
Formosa Plastics
CBI Facility B
Allied Signal
Degussa Corp.
DuPont Co .
Dow Chemical Co .
DuPont Dow
Elastomers
CBI Facility A
Shell Oil Co.
CBI Facility C
Location

Plaquemine, LA
Westlake, LA
Pt. Comfort, TX

Baton Rouge, LA
Waterford, NY
LaPlace, LA
Plaquemine, LA
LaPlace, LA

Norco, LA

Control
Device (s)
Caustic
scrubber
Gas scrubber
Gas scrubber
Water scrubber
& caustic
absorber
Caustic
scrubber
Venturi
scrubber
Wet scrubber
Wet scrubber
Wet scrubber
Wet scrubber
none
Scrubber
2 Caustic
scrubbers
Control
Efficiency
(Percent)
99.8
99.4
>99
>99
>99
99
99
99
>95
95
0
not given
not given
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    Table 2-3.   Storage  Tank HCl  Controls.
Company
Dow Chemical
DuPont
DuPont
PPG Industries
Allied Signal
DuPont Dow
Elastomers
DuPont
CBI Facility B
Vista Chemical
CBI Facility C
LaRoche Industries
Dow Chemical
CBI Facility A
Location
Plaquemine, LA
Parkersburg, WV
Louisville, KY
Natrium, WV
Baton Rouge, LA
LaPlace, LA
Parkersburg, WV

Lake Charles,
LA

Baton Rouge, LA
Plaquemine, LA

Control
Device (s)
Gas Scrubber
Scrubber
Scrubber
Scrubber
Wet scrubber
Wet scrubber
Scrubber
Scrubber
Floating roof
Scrubber
None
None
None
Control
Efficiency
(percent)
99.9
99 .85
>99
99
98
95
90
90
86.2
not given
0
0
0
Table 2-4.  Transfer Operations HCl Controls.
Company
DuPont
Formosa Plastics
Corp
Dow Chemical
Shell Oil Co.
Location
Louisville, KY
Pt . Comfort,
TX
Plaquemine, LA
Norco, LA
Control
Device
Scrubber
Caustic
scrubber
Gas Scrubber
None
Control
Efficiency
(percent)
>99
>99
not given
0
                     2-43

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 2.4.4     Concentration Emission Limitations

     Comment:  Several commenters (IV-D-06,  IV-D-13,  IV-D-14,  IV-
 D-15,  IV-D-16,  IV-D-18) disagreed with the  basis  for the  proposed
 outlet concentration limits.  They  stated that  the EPA
 established the concentration equivalents to  the  MACT floor based
 on  data that do not accurately  reflect the  variability  of sources
 in  the source  category.  Commenter  IV-D-13  noted  that a recent
 court decision (National Lime Association v.  EPA, 233 F.  2d 625
 [B.C. Cir. 2001]) reiterated the EPA's duty to  consider the
 variability that best-performing sources experience.

     As outlined in the supporting  documentation,5 these  limits
 were developed by applying the  MACT floor percent reduction
 efficiencies to the highest uncontrolled concentrations in the
 data set.  These uncontrolled concentrations  were 2,044 ppmv  for
 HCl and 9,650  ppmv for chlorine.  Commenters  (IV-D-06,  IV-D-13,
 IV-D-14,  IV-D-15, and IV-D-16)  noted that facilities  in the
 source category often have emission points  (with  only one
 exception, all examples raised  by the  commenters  were for storage
 tanks and transfer operations)  that emit much higher
 concentrations of HCl and C12  or emit at much higher  air  flow
 rates than the facilities included  in  the EPA's database.  The
 commenters stated that emission points  with high  concentrations
 would need removal efficiencies  greater than  the  MACT floor
 levels in order to meet the proposed concentration limits, which
 the EPA proposed as being equivalent to the MACT  floor  percent
 removal efficiencies.   Therefore, the  commenters  maintained that
 the proposed emission limits were far  beyond  the  MACT floor and
 not justified.

     These commenters provided  examples to  support their
 position.   One commenter (IV-D-14)  cited an example of  a  transfer
 operation that emits 126,000 ppmv HCl.  After control in  a
 scrubber system with a removal  efficiency of  greater  than 99
percent,  the outlet concentration is 131 ppmv.  The commenter
 cited another example of a storage  tank that  emits greater than
 7,500 ppmv HCl before control.   Another commenter (IV-D-06)
 stated that his facility has a high  air flow  multi-stage  scrubber
 system (approximately 25,000 acfm)  that removes several
pollutants with high control efficiencies,  but could  not  meet the
proposed concentration limits.   The  system would  have to  be
 retrofitted at a cost of $1 million  in  order  to meet  the
 concentration limits.   Commenter  IV-D-13 cited storage  tanks
       Memorandum.  Hartmann,  A.  and Norwood,  P.,  EC/R
Incorporated,  to Maxwell,  B.,  EPA/OAQPS/ESD.  Determination of
Concentration Equivalents  to MACT Floor for the Hydrochloric Acid
Production Source Category.   March 21, 2001. {Docket Item II-B-6}

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containing 21 and 32 weight percent HCl that are controlled by a
scrubber guaranteed by the manufacturer to achieve a control
efficiency of over 99 percent that cannot achieve the proposed
emission limits.  Commenter IV-D-16 also gave an example of a
storage tank that could not meet the proposed concentration
limit, even though the MACT floor emission reduction percentage
is being achieved.  Commenter IV-D-14 noted that the uncontrolled
chlorine concentration from the company's process vents can
exceed 35,000 ppmv.

     Alternatively,  one commenter (IV-D-08)  stated that the
proposed emission limits are not as stringent as they should be.
The commenter stated that the MACT floor control efficiencies are
appropriate,  but that they were inappropriately converted to
equivalent concentration limits.  The commenter stated that the
EPA chose as  equivalent to the MACT floor control efficiency the
highest concentration (e.g.,  12 ppmv HCl)  from the range of
concentrations that  are already being achieved (e.g.,  0.03 - 12.3
ppmv HCl)  and noted  that recent court decisions reiterate that
the EPA must  set the MACT floor at the average already being
achieved by the best performing 12 percent of the sources, not at
a level at which all sources can easily meet.  The commenter
urged the EPA to establish emission limits that are appropriately
stringent based on the MACT floor control efficiencies.

     Commenters offered three basic suggestions on how to deal
with this perceived  problem.   Several commenters (IV-D-13, IV-D-
14,  IV-D-15,  and IV-D-18)  requested that the EPA collect and
examine inlet concentration data from a variety of additional
process vents,  storage tanks,  and transfer operations,  and
develop emission limits that are more appropriate to the actual
inlet concentrations observed in the source category.

     In the absence  of more data,  commenters (IV-D-13,  IV-D-14,
IV-D-15)  encouraged  the EPA to establish a tiered control
efficiency based on  flow rate.  This would avoid the situation in
which already-well-controlled scrubbers with high air flow rates
incur a high  additional cost to achieve the proposed
concentration limit.   Commenters IV-D-13 and IV-D-14 recommended
a 99.4 percent removal efficiency for scrubbers with flow rates
less than 1,000 dry  standard cubic feet per minute (dscfm),  and
95-96 percent removal efficiency for scrubbers with flow rates
greater than  1,000 dscfm.   This suggestion was based on a review
of the data used to  establish the concentration equivalents to
the MACT floor.  The commenters pointed out that the only two
scrubbers in  the EPA's database that achieved a 99.4 percent
removal efficiency have flow rates less than 1,000 dscfm.  Based
on the stack  tests from the industry as well as the EPA's
database,  the commenter stated that a control efficiency of 95 to
96 percent is more accurate for high air flow scrubbers.

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     The  final  suggestion by several commenters  (IV-D-06,  IV-D-
 13,  IV-D-14,  IV-D-15, IV-D-16,  IV-D-18) was that the EPA allow
 compliance with either a control efficiency or an emission limit,
 whichever is  less stringent.  The commenters stated that such an
 alternative would relieve the situation where control devices
 have high removal efficiencies  but cannot meet the proposed
 concentration limits because they have high inlet concentrations.
 Commenter IV-D-14 stated that the alternative compliance options
 are necessary because, given the EPA's small data set and  the
 variability of  inlet concentrations found in the source category,
 the EPA did not have adequate grounds for establishing one HCl
 concentration limit for all process vents, storage tanks,  and
 transfer operations.  The commenter stated that allowing
 alternative compliance options  would eliminate the burden  for
 sources to control trivial amounts of emissions  (e.g., from
 already-well-controlled sources that do not meet the proposed
 concentration limits).  This commenter also countered the  EPA's
 argument that it would be difficult to determine how and where to
 measure a control efficiency (versus the relative ease of
 measuring a concentration)  by stating that,  for most units  in the
 source category, the HCl production unit  (e.g.,  absorber)  is
 easily distinguishable from the control device (e.g.,  scrubber
 system) ,  which would make it relatively easy to measure a  control
 efficiency over the control device.   These commenters cited
 several part 63 NESHAP that contained such alternative emission
 limits.

     Response: First,  we reject the commenters'  opinion that
 additional data are needed to establish these concentration
 equivalents.  As discussed in detail in section 2.4.1,  we  believe
 that our data gathering approach was sound and are not convinced
 that additional data gathering would necessarily result in  data
 that better characterizes the industry.

     However,  we recognize that none of the data used to
 establish the concentration equivalents were from storage  tanks
 or transfer operations.   We agree that uncontrolled
 concentrations from storage tanks and transfer operations  are
 likely to be much higher than those for the process vents  in our
 data set because HCl remains in storage tanks and transfer
 operations for a long enough time for the concentration in  the
vapor to reach equilibrium with the concentration in the liquid,
whereas HCl passes through HCl production units quickly.   We
would expect that,  in many cases,  the vapor space in storage
 tanks and transfer operations will be saturated.   As discussed in
 section 2.1,  we have revised the source category definition to
 include production of  liquid HCl at a concentration of 30  percent
 (by weight)  or greater.   At saturation,  the HCl vapor
 concentration above a 30 percent HCl liquid would be around
 12,000 ppmv.   Applying the  existing source MACT floor reduction

                              2-46

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 efficiencies  (99 percent for storage tanks and for transfer
 operations) to  this concentration results in an outlet
 concentration of 120 ppmv. Applying the new source MACT floor
 reduction efficiencies  (99.9 percent for storage tanks and 99
 percent for transfer operations) to this concentration results  in
 an outlet concentration of 12 ppmv for storage tanks and 120 ppmv
 for transfer operations.  These are the emission limitations for
 storage tanks and transfer operations in the final rule.

     With one exception, the comments did not indicate that the
 uncontrolled concentrations used to determination the emission
 limitations for process vents (2,044 ppmv for HC1 and 9,650 ppmv
 for chlorine)  were inappropriate.  Therefore,  we applied the
 revised existing source MACT floor control efficiencies
 (99 percent for both HCl and chlorine emissions from process
 vents) to these concentrations to obtain 20 ppmv HCl and
 approximately 100 ppmv chlorine.  Applying the new source MACT
 floor reduction efficiencies (99.4 percent for HCl emissions from
 process vents and 99.8 percent for C12  emissions  from process
 vents) to this concentration results in outlet concentrations of
 12 ppmv HCl and 20 ppmv C12  (rounded  up from 19 ppmv) .   These  are
 the emission limitations for process vents in the final rule.   We
 believe instances cited by one commenter (IV-D-14)  regarding
 inlet chlorine concentrations in process vents would be addressed
 by the alternative format in the final rule,  which is discussed
 below.

     We disagree with the commenter who believed that the
 emission limitations were not as stringent as  they should be.
 The percent reduction limits represent the "average" control
 level of the best controlled sources,  in accordance with section
 112(d)(3)  of the CAA.   The alternative concentration limits were
 determined using the appropriate percent reduction limits (which,
 again, were based on the average of the best controlled sources)
 and the available data on control device inlet concentrations.
 In determining the concentration limits,  we made assumptions
 about these inlet concentrations for each type of emission source
 (for example,  we chose the highest concentration)  to consider the
variability that will be encountered by the best-performing
 sources.   We strongly disagree that all sources can easily meet
 these limits and we believe that significant control measures
will be required for facilities to meet the limits.

     Regarding the suggestion to establish a tiered control
 efficiency based on flow rate,  we do not agree with the
 commenters that our available data leads to this conclusion.  As
was shown above in Tables 2-1 through 2-4,  27 of the 38 control
 efficiencies reported were 99 percent or greater.  We believe
 that establishing an emission limitation based on an efficiency
 less than 99 percent would not reflect the level of control

                               2-47

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 mandated  by  section  112  of  the  Clean Air Act.  We would point  out
 that  the  efficiencies  less  than 99 percent are represented  in
 Tables  2-1 through 2-4,  they  just are not among the best
 controlled sources.  Therefore,  the use of these data was not  to
 establish the MACT floor but  to generate an array of
 concentration levels to  characterize the potential uncontrolled
 concentrations  from process vents.

      We do recognize,  nevertheless, that the data may not
 completely characterize  the industry and that sources could
 achieve the  MACT floor reduction efficiency but fail to meet the
 applicable outlet concentration emission limitations.  Further,
 the commenters  alleviated our concerns at proposal regarding this
 form  of emission standard.  We  were concerned that it would be
 difficult to determine how and  where to measure a control
 efficiency but  commenters alleviated this concern by stating that
 the HCl production unit  is distinguishable from the control
 device, which makes it clear where to measure the control device
 inlet and outlet in order to calculate a control efficiency over
 the control  device.

      Therefore,  we have  incorporated the third suggestion of the
 commenters (compliance with either a control efficiency or  a
 concentration limit)  into the final rule.   Owners or operators
 will  have the option of  complying with a percent reduction
 efficiency instead of  the outlet concentration limitation.  For
 storage tanks and transfer operations,  the percent reduction and
 concentration limit are  equivalent assuming that a 30 weight
 percent liquid HCl product is stored in the tanks or used in the
 transfer operations.    For process vents,  the percent reduction
 and concentration limits are equivalent assuming process vent
 outlet concentrations  of approximately 2,000 ppmv HCl and 10,000
 ppmv C12 .  These outlet concentrations were  assumed  in  order to
 take  into account the variability of outlet concentrations  from
 HCl process vents.   The percent  reduction will be measured  across
 the control device,  or series of control devices,  that follow  the
 HCl production unit,  storage tank,  or transfer rack.   We have
 added definitions of "HCl production unit"  and "control device"
 to ensure that there is no confusion regarding where the percent
 reduction must be measured.

     Comment: Regarding the format of the standards,  one
 commenter (IV-D-22)  supported the use of the concentration  limit
 format for the standard because  it does not require two sets of
measurements, as would be the case for a control efficiency
 format.  Another (IV-D-18)  suggested that the compliance options
be either a control efficiency  or a mass emission limit,  such  as
 is used in the HON ( §63 . 113 (c) )  .
                               2-4!

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     Response:  We understand .the commenter's points regarding  the
 advantages of a concentration limit format,  and have retained
 this format in the final rule.  However, as discussed above, we
 were compelled to also provide the option of complying with a
 percent reduction emission limitation to ensure that the rule
 provides flexibility to deal with the variability of the
 industry.   We do not feel that a mass emission limit would
 provide this flexibility, as it could lead to restrictions in
 production, which we do not believe are warranted in this
 situation.   Therefore,  the final rule does not contain emission
 limitations in the format of a mass emission limit.

     Comment:  Two commenters (IV-D-15, IV-D-18)  recommended that
 the EPA establish separate emission limitations for control
 equipment  that  was installed on emission points at HC1 production
 facilities  prior to the date of the proposed rule (September 18,
 2001).   The commenters  cited §63.113 (c) (1) (ii)  of the HON as an
 example of  such a "grandfather" provision.

     One commenter (IV-D-15)  recommended that the EPA use the
 same 95 percent control efficiency requirement for grandfathered
 control devices that was used in the HON.

     One commenter (IV-D-18)  suggested that  the EPA require
 facilities  to reduce emissions from grandfathered control
 equipment  by a  certain  percent reduction or  to a specified mass
 emission rate,  whichever is less stringent.   The commenter
 further suggested that  the specific limits  be based on an
 evaluation  of accurate  data on existing control devices.

     Response:  While the HON does  contain the provisions referred
 to by the  commenter,  it has not been our policy in subsequent
part 63 NESHAP  to allow existing control devices to be
 "grandfathered" in this manner.   Given the  high levels of control
present in  this industry at the baseline, we do not believe it is
warranted  to allow such exemptions for facilities with
 substandard controls.

2.4.5    Transfer Operations

     Comment:  One commenter (IV-D-19)  requested that the EPA
reconsider  the  need to  set emission limitations for transfer
operations.  The commenter noted that emissions from transfer
operations  contribute less than one percent  of the total
emissions  from  HC1 production facilities, according to the EPA's
dataset.   The commenter further stated that  most transfer
operations  at HCl production facilities are  already controlled
and that further control would contribute little additional
environmental benefit.
                               2-49

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     Response: The available information is consistent with  the
 commenter's statement  that  "most transfer operations are  already
 controlled."  Indeed,  the MACT floor for transfer operations was
 determined to be 99 percent control efficiency because most
 transfer operations are already controlled  (three of the  four  in
 our dataset).  Section 112(d) of the CAA requires that we  set
 emission limitations at least as stringent as the MACT floor,
 which we are required  to establish for existing sources based  on
 the average emission limitation achieved by the best-performing
 existing sources, regardless of the percentage of total emissions
 attributable to the specific equipment or process.  For new
 sources, we are required to establish the MACT floor at a  level
 not less stringent than the emission control that is achieved  in
 practice by the best controlled similar source.   Sources  that  are
 subject to the proposed rule and are already controlled to the
 level of the proposed standard would not need to install any
 further controls beyond those that are already installed.  We
 have not deleted or changed the emission limitation for transfer
 operations in the final rule.

 2.4.6     Equipment Leaks

     Comment:  Many commenters (IV-D-06,  IV-D-09,  IV-D-12,  IV-D-
 13, IV-D-14,  IV-D-15,  IV-D-16,  IV-D-17,  IV-D-18,  IV-D-22)
 submitted comments regarding the proposed LDAR plan.  Several
 commenters (IV-D-14,  IV-D-16,  IV-D-17)  argued that the EPA should
 eliminate any and all references to an LDAR plan from the
proposed rule.  One commenter (IV-D-09)  agreed that monitoring
 for leaks using instruments is unnecessary,  and stated that an
LDAR plan based on visual observation is consistent with his
company's operating practices.   The commenter asked for
clarification of the flexibility allowed for components that
cannot be visually inspected,  such as underground transfer lines.
Some commenters stated that formal LDAR requirements are not
necessary because HC1 leaks are easily identified (humans can
smell HCl leaks at less than 10 ppm and can easily see the
corrosion that results from leaking HCl)  and facilities typically
identify and repair leaking equipment as part of their routine
maintenance activities due to the health and safety concerns
associated with leaking HCl.  One commenter (IV-D-22)  added that
there is no analytical instrument or monitor with which
facilities can detect HCl leaks.    The commenters argued that
formalizing existing leak detection and repair activities with
labor-intensive monitoring,  inspection,  reporting,  and
recordkeeping activities does not provide any additional
environmental  benefit.

     Most of the commenters requested that the EPA eliminate the
requirement to submit the LDAR plan to a permitting authority  for
review and approval.   Several commenters (IV-D-09,  IV-D-18)

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 stated that they are not aware of any NESHAP that requires LDAR
 plans to be submitted for approval,  and noted that the HON does
 not have such a requirement.  One commenter  (IV-D-14) claimed
 that requiring facilities to submit LDAR plans for approval
 constitutes a "beyond the floor" requirement.  The commenters
 stated that requiring these plans to be submitted for approval
 effectively makes them part of a facility's Title V operating
 permit and, consequently, implementation of the initial plan and
 any changes to the plan would require a formal permit amendment,
 which is a time-consuming (6-18 months)  and unnecessary burden.
 Several commenters (IV-D-09, IV-D-12,  IV-D-13)  noted that the
 proposed rule does not address how the plan is to be approved,
 and requested that,  if the requirement to submit the plan is not
 eliminated, the EPA provide criteria for permitting authorities
 to use in reviewing LDAR plans.   The commenters asserted that
 eliminating the requirement to submit LDAR plans alleviates the
 burdens associated with Title V permits and also allows informal
 or routine maintenance programs to constitute the LDAR plan.  Two
 commenters (IV-D-12,  IV-D-13)  suggested that the LDAR plan be
 included as an addition to a facility's SSM plan.   This would
 ensure that the plan is generated,  maintained,  and available for
 inspection on-site,  while eliminating the difficulties associated
 with Title V permits.   The plan itself would not be part of the
 Title V permit,  only the requirement to keep the plan on-site.

     One commenter (IV-D-18) proposed that the EPA require only
 the following LDAR activities:   (1)  if you see,  smell,  or hear a
 leak,  make the first attempt to repair within 5 days, and repair
within 15 days,  and (2)  maintain records of leaks and when they
were repaired.

     Response: In developing the proposed rule,  we determined
 that the MACT floor for leaking equipment is a general plan to
detect and repair leaks of HCl because most HC1 production
 facilities are already performing leak detection and repair
activities.  Again,  we are required to establish the MACT floor
based on the average emission limitation achieved by the best-
performing existing sources.  We cannot eliminate "any and all
references" to requirements to detect and repair leaks.  We also
believe it is important that LDAR plans be submitted to the
Administrator to facilitate enforcement of this rule and public
access to non-confidential plan requirements, and this rule
 retains the proposed requirement for submittal.   However,  in
response to the commenters'  concerns,  we have eliminated the
proposed requirement that LDAR plans be affirmatively approved.
 Instead,  we have clarified that any deficiencies in LDAR plans
must be promptly corrected upon request by the Administrator, in
order to allow the Administrator to review and approve LDAR plans
 if she so chooses.
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     Moreover, we  do  not  intend that  the  contents of a LDAR  plan
 itself must be included in  a  facility's Title V permit.    Rather,
 like other requirements of  this final  rule,  the requirements to
 develop,  implement, and submit  a LDAR  plan  to control emissions
 from equipment leaks  - but  not  the  contents  of the plan  -  are
 applicable requirements under Title V  and must be reflected  in a
 facility's Title V operating  permit.   We  have clarified  that you
 may incorporate by reference  into your LDAR  plan existing  manuals
 that describe LDAR activities required under other federally
 enforceable rules, provided that copies of all manuals that  are
 incorporated by reference are submitted to the  Administrator.
 We are also requiring that  a  current copy of the plan be
 maintained on-site, and that  previous  versions be maintained on-
 site for  a period  of  5 years  after  any revision of the plan.

 2.4.7     Wastewater Treatment  Operations

     Comment: Several commenters (IV-D-09, IV-D-12,  IV-D-13,  IV-
 D-16,  IV-D-19) supported the  EPA's  decision  not to set any
 emission  limitations or work  practice  standards for wastewater
 treatment operations.  One  commenter  (IV-D-09)  stated that HCl  is
 used in the wastewater treatment operations  to neutralize
 wastewater and added that the facility might use an alternative
 acid for  that purpose if the  operations were subject to emission
 limitations solely because  there was an HCl  production facility
 on-site.  The commenter further  stated that  it would be
 inequitable to require emission  controls  on wastewater treatment
 operations at a facility that produces HCl and uses it for
 wastewater neutralization while  not requiring controls for an
 identical operation at a facility that purchases HCl for
 wastewater neutralization.  Two  commenters  (IV-D-12,  IV-D-19)
 noted that HCl-containing wastewater contains HCl in diluted
 concentrations,  which have very  low vapor pressures (e.g., 11
 ppmv for a 10 weight percent  HCl  solution at 25°C)  and,
 therefore, very low emissions, making  control unnecessary.
 Several commenters (IV-D-13,  IV-D-16,   IV-D-19)  concurred that  HCl
 emissions from wastewater treatment operations are very low.

     Response:  We would point out  that,  as with storage tanks
 and transfer operations,  we selected the MACT floor as MACT  for
wastewater treatment operations,  rather than more stringent
 controls.   However, unlike for storage tanks and transfer
 operations,  the data we had indicated  that none of the facilities
use add-on controls to reduce emissions from wastewater treatment
 operations.   The data also indicated that no process changes or
 other  pollution-prevention type  measures  to reduce HCl emissions
 from wastewater treatment operations are currently used.    The
MACT floor,  consequently,  was no  emission reduction for new and
 existing sources.   In the final  rule,   we have kept wastewater
 treatment operations in the affected source without any emission

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 limitations or work practice standards.  As discussed in the
 preamble to the proposed rule,  we believe that all of the
 operations within the definition of "affected source" are
 sufficiently interrelated that it would be problematic for
 owners, operators and regulators to create separate affected
 sources for different types of emission sources.   We also believe
 that including wastewater treatment operations in the affected
 source even without requiring emission limits or work practice
 standards will facilitate consideration of wastewater treatment
 operations in future site-specific MACT determinations or
 rulemakings.

     Comment:  One commenter (IV-D-19)  requested clarification
 that wastewater collection equipment (e.g.,  sumps,  individual
 drain systems,  oil-water separators,  surface impoundments,
 containers)  is not subject to any of the proposed emission
 limitations or work practice standards.

     Response:  We agree that equipment associated with wastewater
 treatment operations should not be subject to any emission
 limitations or work practice standards.  We have revised the rule
 language in §63.8990(b)(5)  to state that there are no emission
 limitations or other requirements for  equipment used for HC1
wastewater operations.

 2.5  COMPLIANCE ISSUES

 2.5.1     Performance Testing

     Comment:  Many commenters (IV-D-06, IV-D-11,  IV-D-12,  IV-D-
 13, IV-D-14,  IV-D-15,  IV-D-16,  IV-D-18, IV-D-21)  stated that
annual performance testing of scrubbers is unnecessary and
requested that the requirements for annual performance testing be
deleted from the proposed rule.   Two commenters (IV-D-13,  IV-D-
 16) suggested that States be allowed to set performance testing
 frequencies in facilities'  operating permits.   The commenters
stated that the initial performance test is sufficient to
demonstrate initial compliance  and establish operating parameter
ranges and that monitoring of those parameters is sufficient to
demonstrate continuous  compliance because scrubbers operate very
consistently and reliably,  as long as  they are operated within
 the operating parameter ranges.   The commenters further stated
 that performance tests  are expensive and provide no additional
environmental benefit,  and that the cost of annual performance
 tests was not accounted for in  the cost impact analysis.  Two
commenters (IV-D-06, IV-D-14)  stated that the cost of an annual
performance test is $10,000 per scrubber,  and that there are
usually at. least several scrubbers at  an HCl production facility.
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     The commenters  stated  that other NESHAP  (e.g., Cellulose
 Products Manufacturing NESHAP) only require periodic parameter
 monitoring after the initial performance test.  One commenter
 (IV-D-11) pointed out that  the EPA's authority, under  §63.7(a)(3)
 of the General Provisions,  to require a facility  to conduct a
 performance test at  any time for the reasons  stated in  section
 114 of the Clean Air Act makes annual performance  testing
 requirements unnecessary.   Several commenters  (IV-D-14,  IV-D-15,
 IV-D-21) suggested that repeat performance tests  only be required
 after a modification that requires a permit change and/or affects
 emissions has been made to  the affected source.   One commenter
 (IV-D-15) further suggested that alternate means  of compliance
 (e.g., engineering assessments, design evaluations,
 representative testing of similar vent systems, past performance
 test results) be allowed for demonstrating compliance after a
 modification.

     Response: We agree with the commenters that  it is  reasonable
 to perform subsequent performance tests less  frequently than
 annually and have decided to change the requirement for
 subsequent performance testing from annually  to every 5 years or
 each time a facility's Title V permit is renewed, whichever is
 more frequent.  Additionally,  as discussed in response  to
 comments below,  we have decided to allow facilities to  use
 alternate means of demonstrating both initial and  subsequent
 compliance for storage tanks and transfer operations.

     Comment: Several commenters (IV-D-12,  IV-D-13, IV-D-16, IV-
 D-22)  stated that the time  period allowed for facilities to
 conduct subsequent annual performance tests should be changed.
 The commenters stated that  the two-month window allowed for the
 first subsequent annual performance test (10  to 12 months after
 the initial performance test)  is insufficient because  (1) it
 takes time to submit a notice to the permitting authority,  meet
with them to review the test plan,  and receive approval of the
 test plan,  and (2)  facilities may not be operating at
 "representative" operating  conditions during  that window and
would need to change to other,  non-income-generating process
 conditions in order to perform the test under representative
conditions.   The commenters suggested that a  six-month  window be
provided for subsequent annual performance tests;  two of the
commenters (IV-D-12,  IV-D-13)  further suggested that the specific
bounds of this window be established by agreement with  the
permitting authority when the initial performance  test  plan is
reviewed.  One commenter (IV-D-22)  suggested  that  subsequent
performance tests be performed on or after the date of  the
 initial test but no more than 14 months after the  initial test.

     Response:  In response  to the previous comment, we  have
changed the requirement for subsequent performance testing from

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 annually to every 5 years or each time a facility's permit  is
 renewed, whichever is more frequent.  Therefore, this comment  is
 no longer relevant.

     Comment: Several commenters (IV-D-09,  IV-D-13, IV-D-14, IV-
 D-15, IV-D-16, IV-D-19,  IV-D-22) stated that the performance test
 requirements in the proposed rule are not appropriate for storage
 tanks and transfer operations.  Several commenters  (IV-D-09, IV-
 D-19, IV-D-22) stated that storage tanks and transfer operations
 are batch operations which often do not operate for long enough
 time periods to conduct three one-hour sampling runs.  One
 commenter (IV-D-09)  gave the example of a 12,000 gallon tank
 located at his facility's wastewater treatment plant which  is
 occasionally filled with liquid HC1 at a rate of 50 gallons per
 minute and stated that the 240 minutes that it would take to
 completely fill the tank,  if it were empty,  is insufficient for
 performing three one-hour sampling runs and the associated
 activities (e.g.,  determining the volumetric flow rate,
 calculating the sampling flow rate to achieve isokinetic
 conditions,  and cleaning the sample train between test runs).
 The commenter noted that,  if a sampling contractor needed to
 visit the facility on two or more separate occasions in order  to
 complete three sampling runs,  the performance testing cost would
 be higher than estimated for a single test.   This commenter (IV-
 D-09) additionally noted that the scrubber vent on a storage tank
 like the example he  cited would have a very low volumetric  flow
 rate (e.g.,  6.7 acfm),  and usually a curved vent pipe (a "goose
 neck")  that would have to be modified in order to measure vent
 gas velocity using traditional methods.    Another commenter (IV-
 D-16) also stated that some control devices (e.g.,  water eductor
 on a storage tank)  are not designed with locations for measuring
parameters or HAP concentration.  Another commenter (IV-D-13)
noted that performance tests should not be required for small
 storage tanks because they have very low emissions which could
not reasonably be expected to cause adverse human health effects.

     Several commenters suggested alternate means of
demonstrating compliance for storage tanks and transfer
operations.   One commenter (IV-D-14)  requested that all testing
 requirements for storage tanks and transfer operations be removed
 from the proposed rule because the EPA has published established
methods (e.g.,  AP-42,  TANKS software) for calculating emissions
 from storage tanks and transfer operations.   One commenter  (IV-D-
 15)  suggested alternative means including:  engineering
 assessments,  design  evaluations, representative testing of
 similar vent systems,  and past performance test results.  The
 commenter stated that performance tests are unnecessary for
 storage tanks and transfer operations because they are designed
with ample margins of safety based on their maximum filling
 rates.   One commenter (IV-D-16) requested that facilities be

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 allowed  to demonstrate compliance using a design evaluation,  as
 per the  RON  (§63.120(d)). One  commenter  (IV-D-19) suggested  that
 design evaluations be allowed  as a means of compliance
 demonstration for control devices on storage tanks and transfer
 operations, as per the HON  (§63.138 (j)) and the Polyether Polyols
 MACT  (§63 . 1426(f)) .  One commenter  (IV-D-22) recommended that  the
 EPA shorten the  required sampling periods for performance tests
 for storage tanks and transfer  operations.  One commenter  (IV-D-
 09) recommended  that the performance testing frequency be changed
 to five  years,  instead of one year, and cited the Standards  of
 Performance for New Stationary  Sources for Commercial and
 Industrial Solid Waste Incineration Units as an example of a
 recent rule that allowed for a  lower testing frequency.

     Response:  We appreciate the comments and have decided to
 allow design evaluations as an  alternate means of demonstrating
 both initial and subsequent compliance for storage tanks and
 transfer operations that are independently controlled  (e.g., not
 routed to a control device that also controls HCl process vent
 emissions or any other continuous vent stream).   The final rule
 requires that the design evaluation include documentation
 demonstrating that the control  technique being used achieves  the
 required control efficiency when a liquid HCl product with a
 concentration of 30 weight percent or greater is being loaded
 into the storage tank,  or a tank truck, rail car, ship, or barge.

     Comment: Several commenters (IV-D-14,  IV-D-15,  IV-D-18, IV-
 D-22)  disagreed with the proposed requirement that all affected
 HCl production facilities must  conduct performance tests for
 chlorine from process vents.

     One commenter {IV-D-18) stated that chlorine is only present
 in process vent emission streams at facilities that burn chlorine
 to produce HCl,  not at facilities that produce HCl as a by-
product,  and requested that the testing requirements for chlorine
 only be applied to facilities that burn chlorine to produce  HCl.
One commenter (IV-D-22)  stated  that the EPA did not provide  any
 supporting references for its claim that chlorine gas is emitted
 from HCl production processes and noted that,  while HCl and
chlorine can form an equilibrium,  the temperature required to
 shift the equilibrium to form measurable amounts of chlorine is
much higher than typical process conditions.  One commenter  (IV-
D-14)  requested that facilities be allowed to demonstrate through
 the use of design parameters, process knowledge,  and/or previous
performance test results that chlorine (or HCl)  is not likely to
be present in a process vent emission stream and, therefore, be
exempted from the requirement to conduct a test  for chlorine  (or
HCl).   The commenter asserted that the Notice of Compliance
 Status is the appropriate medium for facilities  to report to EPA
which emission  points are appropriate to be tested for which HAP.

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 The commenter suggested language similar to that used in the HON
 (§63.145(a) (6)) be used in the rule.  Another commenter  (IV-D-15)
 suggested  that facilities be required to demonstrate the presence
 or absence of chlorine in the process vent emission stream
 through an initial performance test or documentation of process
 knowledge and then be exempted from further testing for chlorine
 if it is demonstrated to be absent.  The commenter also cited the
 HON (§63.145(a) (6) ) .

     Response: First, the docket for the proposed rulemaking does
 include numerous supporting references for our assertion that
 chlorine can be emitted from HCl production process vents.   Of
 the 21 facilities for which we had emissions data for HCl
 production process vents,  16 reported emissions of chlorine.  In
 fact,  15 of these 16  facilities do not produce HCl in a direct
 synthesis process (e.g.,  from "burning chlorine").   However, we
 acknowledge that there are a variety of processes that produce
 HCl,  not all of which have the potential to emit chlorine.
 Therefore,  we have added a provision to the final rule allowing
 facilities to use process knowledge and previous performance test
 results to demonstrate that chlorine is not likely to be present
 in a process vent emission stream.   This provision allows
 facilities to be exempted from the requirement to test process
 vents for chlorine provided that the appropriate documentation is
 submitted with the site-specific test plan.

     Comment: Two commenters (IV-D-13,  IV-D-16)  requested that
 facilities be allowed to use existing performance test data to
 demonstrate initial compliance in lieu of conducting an initial
performance test.   One commenter (IV-D-13)  suggested that
 language similar to that used in the Hazardous Waste Combustors
NESHAP (§63.1206(b)(7))  be incorporated into the proposed rule.
 One commenter (IV-D-16)  stated that many facilities have already
 conducted testing of  affected emission streams to demonstrate
compliance with other Federal or State standards and continue to
operate in the same manner as when the testing was conducted.

     Response: We concur with the commenter's request and have
added a provision to  the final rule allowing facilities to use
existing performance  test data to demonstrate initial compliance
 for the emission point on which the test was conducted if (1) the
performance test was  conducted within the previous 5-year period,
 (2)  the performance test was conducted using the same test
methods required by this rule,  and (3)  no modifications have been
made to the process or emission point since the previous
performance test was  conducted or the owner or operator can
 demonstrate that the  results of the performance test, with or
without adjustments,  reliably demonstrate compliance despite
process changes.
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      Comment:  Two  commenters  (IV-D-12,  IV-D-13)  requested that
 the  requirements in  §63.7 (c)  of the General  Provisions  to have
 site-specific  test plans reviewed and approved  should be  waived
 for  all  but the initial  performance test.  The  commenters noted
 that §63.7(b)(1) provides  the EPA with  adequate  time and
 authority  to request  and review a test  plan  if  necessary  due  to
 deviations from the  initial test plan.

      Response: In  response to another comment received, we have
 changed  the frequency for  subsequent performance  tests  from
 annually to every  5 years  or  each time  a facility's Title V
 operating permit is renewed, whichever  is more  frequent.   We
 believe  that it is necessary  to develop a site-specific test  plan
 for  each of these  subsequent performance tests because process
 conditions and testing procedures could change during the time
 between  performance tests.  However, the requirement in
 §63.7(c)(2)(i) regarding submission of  site-specific test plans
 for  approval specifies that they are to be submitted "if
 requested by the Administrator," not necessarily  each time a
 performance test is conducted.  Therefore,  we believe that the
 proposed requirements relating to the site-specific test  plan are
 appropriate and we have not changed the requirements in the final
 rule.

     Comment: Two  commenters  (IV-D-13,  IV-D-16) requested that
 representative testing of similar sources (e.g.,  storage  tanks in
 a tank farm that all have identical scrubbers) be allowed.  The
 commenters suggested  that facilities be required  to make  an
 adequate demonstration of the acceptability of representative
 testing  in their site-specific test plan in order to gain
 approval.

     Response: In response to other comments received,  we have
 added a provision to  the final rule allowing facilities to use
 design evaluations in lieu of performance testing for any and all
 of their storage tanks and transfer operations.   Since a  design
 evaluation could be used to show that a performance test
 conducted for one storage tank is sufficient -to demonstrate
 compliance of a similar storage tank,  we have not added a
provision to the final rule explicitly allowing representative
 testing of similar sources.

 2.5.2     Operating Parameters

     Comment:  One commenter (IV-D-12)  requested that the  EPA
 allow facilities to supplement performance test data on operating
parameter ranges with engineering analysis in order to adjust  the
parameter ranges to be consistent with the range of operations  at
 a facility.
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     Response: Since the operating limits that are established
 for an HC1 production facility will be used to demonstrate
 continuous compliance with the emission limitations in the rule,
 we believe that it is important that compliance with the emission
 limitations be initially demonstrated at the actual operating
 limits that are established.   This initial demonstration is
 accomplished by conducting a performance test.  Therefore,  we
 have not changed the requirement that operating limits be
 established based on parameter values measured during a
 performance test.  However,  an owner or operator may establish
 the operating limits based on more than one performance test,
 including tests that were conducted within the past five years on
 the same emission point using the same test methods.

     Comment:  One commenter (IV-D-14)  stated that the proposed
 rule did not clearly define the relationship between performance
 testing and operating limits.   The commenter requested that
 facilities be allowed to delay a performance test for 60 days
 after approval of their site-specific test plan in order to
 ensure that process conditions are such that the operating limits
measured during the performance test will fall within a
 reasonable range.  The commenter stated that this time would
 allow facilities to adjust processes and process controls,  and
 train operators,  in order to ensure compliance with the rule.

     Response: We agree with the commenter that the proposed rule
did not adequately address the relationship between performance
 testing and operating limits.   In response to this comment and
others, we have changed the final rule to clearly state the
procedures for establishing operating limits using performance
 test data,  as well as other information,  if desired.

     However,  we have not added any explicit provisions allowing
facilities 60 days after approval of site-specific test to adjust
processes before conducting the performance test.  The
Notification of Intent to Conduct a Performance Test must be
submitted at least 60 days before the performance test is
scheduled to begin,  but may be submitted more than 60 days before
the test is scheduled to begin if the owner/operator thinks more
time is needed between submission of the notice and performance
of the test.   Facilities are allowed to reschedule performance
tests under §63.7(b)(2)  of the General Provisions.  Under the
final rule,  facilities have until the compliance date to conduct
a performance test.   We believe that these requirements and
provisions allow ample time for the activities mentioned by the
commenter.

     Comment:  Two commenters  (IV-D-12, IV-D-13) stated that the
requirement to verify or report changes in operating limits in
each annual performance test report should not apply to

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parameters that are already specified in the facility's  Title  V
permit.  The commenters noted that it would be illegal to make a
change in operating limits that are specified in the Title V
permit without officially amending the permit.  One commenter
 (IV-D-12) further stated that the requirement to establish
operating limits during a performance test should also exclude
parameters for which a facility already has limits established in
their Title V permit because establishing new limits would be
illegal v/ithout amending the permit.

     Response:  If changes in process conditions,  control device
performance,  or any other situation that results in the  operating
parameters in the Title V permit no longer being appropriate to
demonstrate compliance with the emission limit occurs,  we believe
that the operating limits should be amended.   However,  in
response to other comments received, we have changed the
frequency of subsequent performance tests from annually  to every
5 years or each time a facility's Title V permit is renewed,
whichever is more frequent.  As facilities will have the
opportunity to modify operating limits in their Title V permits
in conjunction with each performance test,  we have not removed
the requirement to verify or report changes in operating limits
in each performance test report.

     Comment:  Two commenters (IV-D-13,  IV-D-16)  stated that the
term "inlet liquid flow rate" is unclear when applied to
recirculating scrubbers.   The commenters requested that  the term
be modified to "inlet liquid or recirculating liquid flow rate,
as appropriate" everywhere that it is mentioned in the proposed
rule.

     Response:  We agree with the commenters and have made the
requested change throughout the rule.

2.5.3      Monitoring- Alternatives

     Comment:  Several commenters (IV-D-06,  IV-D-14,  IV-D-15, IV-
D-16,  IV-D-22)  stated that the operating parameters specified  in
the proposed rule,  especially scrubber effluent pH,  are not
appropriate in  all cases.   One commenter (IV-D-06)  stated that,
for a  water scrubber with any HCl in the effluent,  the pH of the
scrubber effluent will be too low to determine any relationship
to the concentration of HCl in the effluent and,  for a caustic
scrubber,  the pH of the effluent will only indicate whether
caustic is present in excess of the acid being scrubbed.   The
commenter stated that monitoring the pH is only appropriate for
the inlet stream of a caustic scrubber because it would
demonstrate whether the alkalinity is sufficient  for absorption
of HCl.   Two  commenters (IV-D-14,  IV-D-16)  stated that measuring
the pH of a caustic scrubber is not an appropriate way to ensure

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 a sufficient caustic concentration for adequate emission control
 because the pH will always be greater than 14.   Instead,
 commenter IV-D-16's company analyzes grab samples from the
 scrubber once per shift to measure the caustic concentration.
 One commenter  (IV-D-16) gave an additional example of a once-
 through water scrubber which operates very consistently and  for
 which pH monitoring is not necessary because the water flow  rate
 is sufficient to demonstrate continuous compliance,  unless the
 loading to the scrubber changes.  The commenter further stated
 that his company does not typically monitor the flow rate on a
 once-through water scrubber but ratner sets the flow rate at an
 appropriate level or uses a design analysis to be assured that
 the scrubber is operating properly.

     The commenters requested that EPA allow monitoring of
 alternate parameters when pH and the other specified parameters
 are not appropriate.  One commenter (IV-D-06)  pointed out that,
 while the proposed rule has provisions for alternate monitoring
 parameters for control devices other than scrubbers,  it does not
 have explicit provisions for alternate monitoring parameters for
 scrubbers.  One commenter (IV-D-06) stated that some facilities
 may already be monitoring a different parameter than those
 specified for a particular control device or may be using
 different but equivalent monitoring and recordkeeping procedures
 and requested that the EPA add provisions to the proposed rule
 that allow flexibility and accommodate existing monitoring
practices, such as provisions used in the Polymers & Resins  I
MACT (§63 . 506 (f) , (g) , (h) ) .   One commenter (IV-D-16)  requested
 that facilities be allowed to use non-continuous monitoring
methods,  such as grab samples,  when continuous  methods are
 infeasible.   One commenter (IV-D-06)  suggested that appropriate
parameters to monitor to demonstrate continuous compliance using
 a scrubber (water or caustic)  are liquid flowrate or pressure
drop,  or temperature or ionic conductance for a process that
operates at a very consistent steady-state.   One commenter (IV-D-
 15)  suggested that some alternatives to pH monitoring include
 caustic feed rate,  water flow rate, and temperature and requested
 that facilities be allowed to use process knowledge to select the
most appropriate monitoring parameter(s)  for demonstrating
 continuous compliance.

     Response:  Section 63.8(f)  of the General Provisions allows
 facilities to apply for approval to use alternative monitoring
procedures,  and Table 7 in the proposed rule indicates that  these
provisions apply to Subpart NNNNN.   So,  the proposed rule allowed
 for monitoring of alternate parameters.   However,  in order to
 clarify in the rule text that facilities can apply to use
 alternate monitoring parameters, we have added rule language to
 that effect.
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      Comment:  One  commenter  (IV-D-11)  stated  that  his  facility
 uses  a  continuous  emission monitor  (CEM)  to monitor HC1  and
 chlorine  emissions  from an HC1 production facility emission
 point.  The  commenter noted  that  this  requirement  is in  the
 facility's Title V  permit as part of the  early  reduction program.
 The commenter  requested that facilities with  existing  CEM be
 allowed to used data from the CEM to demonstrate continuous
 compliance.

      Response: We encourage  facilities to use monitoring devices
 that  directly  measure pollutant concentrations  to  demonstrate
 continuous compliance with this rule if they  so choose.  The
 commenter is welcome to request approval,  in  accordance  with
 §63.8(f)  of  the General Provisions, to monitor HCl and chlorine
 emissions as an alternative  to the continuous compliance
 procedures specified in the  rule; a performance test would still
 need  to be conducted in order to  demonstrate  initial compliance.
 Such  a  request should include detailed technical specifications
 along with procedures for initial installation, initial
 calibration, initial validation,  quality  assurance, and  quality
 control.  We have often approved  such requests  for MACT  rules.

      Comment:  Two commenters (IV-D-13,  IV-D-16) noted  that the
 requirements for monitoring using a control device other than  a
 scrubber  listed in  §63.9025(d)  conflict with  the requirements
 listed  in Table 5,   item #2.   Paragraphs b, d, and  e of item #2 in
 Table 5 refer  to a  scrubber,  while §63.9025(d) seems to  allow  for
 control devices other than scrubbers.  The commenters  requested
 that paragraphs b,   c, d,  and e for item #2 of Table 5 be deleted
 and a new paragraph  (b) be inserted that  instructs facilities
 using control devices other than  scrubbers to conduct monitoring
 according to their monitoring plan.

     Response: We agree with the  commenter and have changed Table
 5, item #2 to reflect final §63. 9025 (e) (proposed  §63.9025(d) ) ,
which allows facilities using control devices other than
 scrubbers to determine their own monitoring parameters.

2.5.4     Site-Specific Monitoring Plans

     Comment: Several commenters  (IV-D-11, IV-D-12, IV-D-13)
disagreed with the  requirement to submit  the  site-specific
monitoring plan for approval.  One commenter  (IV-D-11)  cited the
absence of a site-specific monitoring plan in general MACT
regulations along with the lack of details in the proposed rule
regarding plan submittal and recommended  that all  requirements
 for the plan be removed from the proposed rule.  Two commenters
 (IV-D-12,  IV-D-13)   stated that requiring  submission of the plan
would result in the details of the plan being included in a
 facility's Title V permit and would cause a delay  in

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 implementation and modification of the plan because of  the
 lengthy  time period typical for approval of elements of a Title V
 permit.  The commenters suggested that the site-specific
 monitoring plan be treated the same way as an SSM plan  (e.g.,
 Title V  permit would require a facility to have the plan but  the
 details  of the plan would not be part of the permit) , thereby
 providing flexibility for facilities to modify the plans while
 ensuring that the plans are available for inspection.

     Response:  It was never our intent that all of the
 substantive provisions of a site-specific monitoring plan
 necessarily would become part of a facility's Title V operating
 permit.  We have changed the final rule to require the site-
 specific monitoring plan to be developed,  implemented,  and
 submitted to the Administrator,  but not subject to the
 Administrator's approval.  We also have clarified that any
 deficiencies in site-specific monitoring plans must be promptly
 corrected upon request of the Administrator,  in order to allow
 the Administrator to review and approve site-specific monitoring
 plans if she chooses to do so.   We expect that the Title V permit
 would contain the requirement to develop and implement the plan
 but not  incorporate the plan itself,  even if the Administrator
 requests the plan to be submitted.  We have also added a
 requirement that a current copy of the plan be maintained on-
 site,  and that  previous versions be maintained on-site for a
 period of 5 years after the revision of the plan.

     Comment:  One commenter (IV-D-12)  stated that the detailed
 requirements in proposed §63.9025(b)  & (c)  for operation,
 inspection,  and maintenance of pH and liquid flow monitoring
 devices are unnecessary because proposed §63.9005(e) and (f)
 require  facilities to develop their own site-specific monitoring
plans with operation,  inspection,  and maintenance procedures.
The commenter requested that proposed §63.9025(b)  & (c)  be
deleted.

     Response:  We included the detailed operation,  inspection,
and maintenance requirements for monitoring devices in the
proposed rule because no Performance Specification had yet been
promulgated for pH or liquid flow monitoring devices.   However,
we are currently developing Performance Specifications for
continuous monitoring systems that must be followed by owners and
operators of all sources subject to standards under 40 CFR part
 63.  Therefore,  we have decided to removed the detailed
 requirements in §63. 9025(b)  & (c)  from this rule and wait for the
 rulemaking that will propose performance specifications for all
 of 40 CFR part  63.   We decided it would be premature to
promulgate performance specifications for this rule when the
 specifications  that would ultimately be promulgated for all of 40
CFR part 63 may be significantly different as a result of

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 possible public  comments  received on  that  rulemaking.   We did add
 language in  the  final  rule  to  require that "all monitoring
 equipment  shall  be  installed,  calibrated,  maintained,  and
 operated according  to  manufacturer's  specifications  or other
 written procedures'that provide  adequate assurance that the
 equipment  would  reasonably  be  expected to  monitor accurately."
 Therefore, owners and  operators  will  be required by  the final
 rule to follow written performance specifications, but not
 necessarily  the  ones that we proposed.  In addition,  the
 requirement  to develop a  site-specific monitoring plan,  which
 must include performance  specifications, is retained in the  final
 rule, as the mechanism for  formalizing the performance
 specifications.

     Until the Performance  Specifications  are promulgated for pH
 and liquid flow  rate,  facilities  can  design their own  operation,
 inspection, and  monitoring  procedures  for  incorporation into
 their site-specific monitoring plans.   Once we promulgate the
 Performance Specifications  for pH and liquid flow monitoring
 devices, facilities that  monitor  pH and liquid flow  rate can
 simply cite these requirements;  facilities  that monitor other
 parameters not covered by promulgated Performance Specifications
 can continue using their  own procedures.

     Comment: Several  commenters  (IV-D-06,   IV-D-11,   IV-D-12,  IV-
 D-13, IV-D-14, IV-D-15, IV-D-16,  IV-D-18,   IV-D-22) stated that
 the inspection and maintenance requirements for monitoring
 equipment are unnecessarily burdensome  and requested that
 facilities be allowed  to  develop  their  own site-specific
 procedures for inspection and maintenance  of monitoring equipment
 instead.

     The commenters (IV-D-06, IV-D-11,  IV-D-12, IV-D-13,  IV-D-14,
•IV-D-15, IV-D-16) stated  that the  requirement to inspect all
 components and electrical and mechanical connections of  the
 monitoring devices monthly  is burdensome since it would result  in
 long periods of  downtime  because  the process and monitoring
 equipment would  need to be  shut down  during inspections.   Several
 commenters (IV-D-12, IV-D-13, IV-D-16)  stated the scope  of "all
 electrical connections" could be  interpreted to be very broad,
 which would mean the inspection requirement would be very
 burdensome.  One commenter  (IV-D-12)  noted that the  inspection
 requirements would also increase  the  recordkeeping burden
 associated with  the additional startups and shutdowns,
malfunctions, and emissions exceedances.   The commenter  added
 that the burden  associated  with the specific detailed
 requirements has not been included in  the  regulatory impact
 analysis and could significantly  increase  the burden such that
 the proposed rule becomes a major  rulemaking.  Several  commenters
 (IV-D-12,  IV-D-13,  IV-D-14)  stated that the monthly  inspections

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would lead to increased HAP emissions because of the additional
startups and shutdowns and because electrical failures would be
more likely after the connections are frequently disturbed.  The
commenters stressed the fact that opening monitoring systems
regularly and disturbing the wires and connections would cause
the systems to fail sooner than if more appropriate inspection
procedures were employed.  One commenter"(IV-D-16)  noted that it
does not make sense to disconnect a functioning system to check
its continuity.   Two commenters (IV-D-11, IV-D-16)  added that any
failure of a monitoring device component would be immediately
apparent because the system readout would default to either the
minimum or maximum of the scale.

     One commenter (IV-D-18)  agreed with the need to conduct
monthly inspections of monitoring devices in order to ensure that
they remain in good working order, but requested clarification of
what types of inspection are required.  The commenter questioned
the meaning of "all electrical connections for continuity."

     Several commenters (IV-D-06,  IV-D-11,  IV-D-13,  IV-D-14, IV-
D-16,  IV-D-22)  stated that the proposed calibration requirements
for pH and liquid flow rate monitoring devices are inappropriate
and should instead depend on the manufacturer's recommendations
and the service  requirements of the specific application.  The
commenters specifically noted that the requirement to calibrate
the pH monitor every 8 hours is unnecessary and would yield three
hours  worth of invalid data per day as well as cause facilities
to incur high maintenance costs.   The commenters stated based on
their  experience that pH monitors are very reliable and weekly or
bi-weekly calibration,  which would result in a 98 to 99 percent
availability of  the monitor,  is sufficient for continuous pH
monitors.   One commenter's (IV-D-11)  facility instead uses two
online pH monitors,  one to control pH and one to monitor pH,
which  are calibrated every two weeks;  additionally,  an alarm is
set to sound when the difference between the two monitors is 0.2
pH units or greater.   The pH is then checked by an independent pH
monitor, and the incorrect unit is recalibrated.  One commenter
(IV-D-14)  noted  that the EPA's Test Method 150.2 allows
facilities to either directly calibrate each pH probe or evaluate
pH measurement accuracy with a "laboratory-type pH meter" and
stated that the  proposed rule contravenes this method.   The
commenter also noted problems inherent in measuring the pH of
particular streams:  (1)  fluorine-containing streams etch pH
probes,  and (2)  sulfur-containing streams plug the pH probe
elements.

     Several commenters (IV-D-06,  IV-D-13,  IV-D-14)  suggested
that the EPA allow facilities to design their own inspection and
maintenance procedures for monitoring equipment and include them
in the facility's SSM plan.  This would ensure that a plan is

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 subject  to agency review on demand while not making  it part  of  a
 facility's Title V permit, thereby avoiding a  6  to 18 month  delay
 when  a change is made to a plan.  One  commenter  (IV-D-14)  cited
 the Polyether Polyols NESHAP  (Subpart  PPP; §63.1438  & 1439)  as  an
 example  of a rule that provides a structure for  facilities to
 describe their site-specific monitoring plans  in their
 Precompliance Report, which is subject to  the  45-day review
 program  and requested that such a program  be included in  the
 proposed rule.  The commenter recognized that  the proposed rule
 does  allow facilities to petition for  alternative monitoring
 plans but found several problems with  this option: (1) permitting
 authorities do not have enough resources to review the large
 number of requests which would likely be generated by this rule,
 and (2)  the review process would not allow facilities adequate
 time  to  design their monitoring plans and be in  compliance by the
 compliance date.

      Response: As stated above, we have removed  all  of the
 specific operation,  inspection, and maintenance  requirements for
 monitoring devices from the final rule because we are planning  to
 propose  similar requirements that will be applicable to all  40
 CFR part 63 sources.   An opportunity will be provided to  comment
 on that  rulemaking after it is proposed.

      In  response to the suggestion that facilities design  their
 own inspection and maintenance procedures  for monitoring
 equipment and include them in a plan, we would point out  that the
 proposed rule included a requirement to develop  a site-specific
 monitoring plan,  which would include such information as
 inspection and maintenance procedures for monitoring equipment.

     Comment:  Two commenters (IV-D-12, IV-D-13)  stated that  the
 requirement to ensure,  and certify annually under Title V, that a
 pH monitor sample is properly mixed and representative is
 impossible to meet.   The commenters requested that the
 requirement be changed to require the monitor installation to be
 designed to provide a well-mixed and representative  sample,
because a design requirement can at least be demonstrated.   The
 commenters also noted,  that the requirement is redundant because
 it is  already covered under §63.8(c)(2) of the General
 Provisions.

     Response:  Section 63.8 (c) (2)  of the General Provisions
 requires continuous  monitoring systems (CMS)  to  be installed such
 that representative measurements of parameters are obtained.   As
 stated above,  the requirement to ensure that a pH CMS sample is
properly mixed and representative,  along with other monitoring
 operation, inspection,  and maintenance requirements,  has been
removed from the final rule.
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 2.5.5     Other Comments Regarding Monitoring

     Comment: Two commenters  (IV-D-09, IV-D-19) requested  that
 the proposed rule be revised  to state that continuous parameter
 monitoring is only required while the HC1 production process
 equipment is operating.  One  commenter suggested that periods of
 stoppage for maintenance and  repairs should be covered under a
 facility's SSM plan.

     Response:  The proposed rule stated,  in both §63.9025(a)(1)
 and §63.9035(d), that continuous parameter monitoring is only
 required while the affected source is operating.  The proposed
 rule further stated in §63.9035(d)  that continuous parameter
 monitoring is required during "periods of startup,  shutdown, or
 malfunction when the affected source is operating," but not
 during periods of "monitor malfunctions,  associated repairs, and
 require quality assurance or control activities (including, as
 applicable,  calibration checks and required zero and span
 adjustments)."   Therefore,  we believe that the rule already
 addressed the commenter's request and these provisions remain in
 the final rule.

     Comment: One commenter (IV-D-12) requested that only one
 valid data point per minute be required to be used to calculate
 the hourly average when data are available more often than that.
 The commenter noted that modern computers collect many data
 points per second,  but the data are often not retained long
 enough to be used to calculate an hourly average.   The commenter
 cited the HON,  the Standard Standards (Subpart SS) ,  and the SOCMI
 Consolidated Air Rule as examples of rules that have such a
 requirement.

     Response:  We agree with the commenter and have changed the
 final rule to state that,  for data collected using an automated
 CMS,  you must use at least one measured value per minute to
 calculate hourly average values if values are measured more than
 once per minute.

     Comment: One commenter (IV-D-16) requested that monitoring
 data not be required to be collected during periods of
maintenance and calibration.   The commenter suggested that the
 requirement to  have valid data for 75 percent of the hours in a
 24-hour period  specifically exempt hours during which maintenance
 and calibration are performed.

     Response:  The proposed rule does not require facilities to
 collect monitoring data during periods of "monitor malfunctions,
 associated repairs,  and required quality assurance or control
 activities (including,  as applicable, calibration checks and
 required zero and span adjustments)" [proposed §63.9035(d)] .  We

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 believe  that  25  percent  of operating hours  is  a  sufficient amount
 of  time  to perform  calibration and maintenance activities,  and
 that valid data  can reasonably be expected  to  be obtained during
 the other 75  percent of  the operating hours.   Therefore,  we
 disagree with the commenter's request to exempt  periods  of
 calibration and  maintenance from the requirement to have valid
 data for 75 percent of the hours in a 24-hour  period.  However,
 we have  clarified that valid data are required for 75 percent  of
 the "operating hours"  (e.g., the hours during  which the  affected
 source is operating)  in  a 24-hour period.

 2.5.6     Compliance During SSM Events

     Comment: One commenter (IV-D-07) stated that it could
 sometimes be  difficult to comply with the section of the General
 Provisions which states  that owners or operators must minimize
 emissions at  an  affected source "at least to the  levels  required
 by all relevant  standards," even during periods  of startup,
 shutdown, and malfunction (§63.6(e)(1)(i)).  The commenter gave
 an example of a  situation in which an air pollution control
 device malfunctions  and cannot meet an emission  limitation (e.g.,
 12 ppm HC1 and/or 20 ppm C12  in the proposed rule) .   The
 commenter suggested that the EPA allow affected  sources  to take
 measures to prevent  or minimize excess emissions to the  extent
 practical,  rather that to the level of the  standard,  during
 periods of startup,   shutdown,  and malfunction.

     Response: This  comment addresses the General Provisions
 rather than the  proposed HCl Production rule,  so we cannot
 consider any  rule changes based on this comment.   However,  we
 note that we proposed to revise this language  in the General
 Provisions (66 FR 16318)  to state that owners  or operators  shall,
 "at all times, including periods of startup, shutdown,  and
 malfunction,"  minimize emissions "to the levels required by the
 relevant standards,   i.e., meet the emission standard or  comply
 with the startup, shutdown,  and malfunction plan."

     Comment:  One commenter (IV-D-14)  requested that the EPA
 address the issue of monitoring requirements during SSM  events
 that are addressed  in the SSM plan.   The commenter suggested that
 a provision be added to the proposed rule similar to §63.1420(h),
which states  that facilities do not have to collect monitoring
data during an SSM  event if the owner/operator has provided
 justification in the Precompliance Report for  shutting down the
monitoring device during the specific SSM event and received
approval from the Administrator.

     Response: The proposed rule did address the issue of
monitoring requirements during SSM events in §63.9035(d),  which
 requires facilities   to collect monitoring data during periods  of

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SSM when the affected source is operating.  We do not believe
that a provision exempting facilities from collecting monitoring
data during SSM events,  under certain circumstances, is
necessary.  The commenter did not provide any technical basis for
why such a provision would be necessary for this specific
industry.

2.6  NOTIFICATIONS, REPORTS,  AND RECORDS

2.6.1     Submission Dates

     Comment:  One commenter (IV-D-06) stated that there are
inconsistencies between the General Provisions and the proposed
rule regarding dates for testing and reports.   The commenter
stated that the proposed rule appears to require performance
testing and submission of the Notice of Compliance Status  (NOCS)
before the compliance date,  whereas the General Provisions set
deadlines for these activities after the compliance date.

     Response:  We acknowledge the referenced inconsistency
between the proposed rule and the General Provisions and have
changed the final rule to conform with the General Provisions.
The final rule requires  the performance test to be completed
within 180 days after the compliance date.  The final rule does
not change the requirement to submit the NOCS within 60 days
after completion of the performance test,  because this
requirement was already consistent with the General Provisions.

     Comment:  Several commenters (IV-D-07, IV-D-12,  IV-D-13)
requested that owners or operators be allowed to submit
semiannual compliance reports 60 days after the end of each
semiannual reporting period,  rather than the 30 days that is
specified in the proposed rule.   Two commenters (IV-D-12, IV-D-
13) stated that,  since there are similar schedules for Title V
and State reports,  a minimum of  60 days would be necessary for
facilities to  review and compile all of their monitoring data for
all of their semiannual  compliance reports.   One commenter  (IV-D-
07) stated that this change would be consistent with other
NESHAP,  such as the Oil  and Natural Gas NESHAP and the HON.

     Response:  We believe that 30 days is sufficient time to
prepare and submit semiannual compliance reports.   An owner or
operator is not required to include all monitoring data from the
reporting period in the semiannual compliance report, but rather
to report information regarding each deviation from an emission
limitation and each SSM event.   If no deviations or SSM events
have occurred during the reporting period, relatively little time
should be required to prepare a report stating so.  If deviations
or SSM events  have occurred during the reporting period, the
owner or operator should be documenting the information required

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 for each event as soon as  it occurs, rather than waiting  until
 the end of the reporting period to document all of the deviations
 and SSM events.  Furthermore,  the proposed rule allows a  facility
 whose permitting authority has already established dates  for
 submitting semiannual compliance reports pursuant to 40 CFR
 70.6(a)(3)(iii)(A) or 71.6(a)(3)(iii)(A) to submit reports for
 this subpart according to  those dates.   Therefore, we have not
 changed the requirements for the submission of semiannual
 compliance reports in the  final rule.

 2.6.2     SSM Reports

     Comment: Several commenters (IV-D-07,  IV-D-12, IV-D-13)
 requested that the EPA allow reports of startups,  shutdowns,  and
 malfunction events to be submitted with the semiannual compliance
 report rather than as individual immediate reports following  each
 event.  Both commenters stated that this change would be
 consistent with other NESHAP,  including the HON.

     Two of the commenters (IV-D-12, IV-D-13)  stated that most
 deviations from the SSM plan involve paperwork variances with no
 impact on emissions.   Further,  the commenter stated that,  for
 events that do have a potential impact on emissions or require
 community response,  facilities are required to submit reports
 within 15 minutes to one hour of the event under CERCLA,  SARA,
 and State requirements.   The commenter concluded that no purpose
 is served in submitting reports to the EPA or delegated authority
 2 days and one week after an SSM event.

     Response:  Immediate SSM reports are only required when an
 SSM event is inconsistent with a facility's SSM plan.   So, the
more thorough a facility's SSM plan is,  the fewer events will
 trigger this immediate reporting requirement.   The requirement to
 submit immediate  SSM reports 2  days and 7 days after an SSM event
 that is inconsistent with a facility's  SSM plan is based on
 §63.10(d)(5)(ii)  of the General Provisions.  We believe that  this
requirement is  necessary in order to ensure that the proper
authorities are made aware of such events.   Therefore,  we have
retained the requirement for immediate  SSM reports in the final
rule.

2.6.3      Unnecessary/Burdensome Reporting and Recordkeeping
          Requirements

     Comment:  One commenter (IV-D-15)  questioned the need for
semiannual compliance reporting and recommended that,  as an
alternative,  facilities  be required to  keep records on-site for
review by compliance personnel.
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     Response:  The General Provisions require facilities subject
 to part 63 NESHAP to semiannually report excess emissions and
 monitoring system performance.  The semiannual compliance report
 required by the proposed rule is consistent with the mechanism
 used by other part 63 NESHAP to submit the required information.
 We believe that it is necessary to submit this information,
 rather than simply keep records on-site for review by compliance
 personnel, because it provides better compliance assurance.
 Therefore, the final rule retains the requirement to submit
 semiannual compliance reports .

     Comment:  Two commenters (IV-D-15, IV-D-18)  requested that
 the EPA eliminate the requirement to calculate and keep records
 of daily,  hourly,  and annualized CMS data.   The commenters
 recommended that facilities record and,  perhaps,  periodically
 report the occasions when their emission control devices are
 malfunctioning or operating at less than their known efficiency.
 The commenters suggested that these reporting and recordkeeping
 requirements be established in a facility's SSM plan rather than
 in the rule.

     Response:  The proposed rule required owners or operators to
 collect parameter monitoring data and calculate hourly and daily
 averages,  as well as keep records of the collected and calculated
values.  We believe that these requirements are reasonable,
 especially given the computer technology that is readily
available to record data and perform calculations.   Further, we
believe that these records are necessary in order to demonstrate
compliance,  and that merely keeping records of non-compliance
events would not be sufficient to demonstrate compliance.

     Comment:  Two commenters (IV-D-12, IV-D-13)  commented on the
requirement to include information about CMS downtime in
semiannual compliance reports.   The commenters requested that the
requirement to report the date and time that each CMS was
inoperative and the requirement to report the total duration of
CMPS downtime both explicitly exclude times when the CMS is
inoperative for pH calibration checks and other inspection and
maintenance activities required by the proposed rule.  The
commenters stated that the required calibration and inspection
and maintenance (I/M) requirements will result in a high amount
of downtime which will overshadow the effect of downtime due to
true problems.

     Response:  We understand the commenter's concern regarding
including downtime for required I/M activities in the reported
total downtime for CMS.  However, the requirement to report total
CMS downtime is based on a similar requirement in the General
Provisions  (§63.10(e)(3)(vi)(J)), so we have not removed it from
 the final rule.  The owner or operator may, however, report a

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 breakdown  of  the  total CMS downtime into periods due  to
 calibration and I/M  activities, monitoring malfunctions,  and
 other  applicable  causes.

     Comment: Two commenters  (IV-D-12, IV-D-13) requested that
 the requirement to include a brief description of the process
 units  in each semiannual compliance report be deleted.  The
 commenters stated that a description of an HCl production process
 unit is already given in the rulemaking package and that
 repeating  the description every six months is an unnecessary
 burden.

     Response: First, the requirement to include a brief
 description of the process units in each semiannual compliance
 report is  intended to be more than merely repeating the generic
 process description  included in the rulemaking package.   The
 intent of  the requirement is for an owner or operator to  give
 their permitting  authority a more detailed description of  the
 specific equipment at their facility that is subject to this
 subpart.   Once these process descriptions have been written  for a
 facility,  we do not believe it is a burden to simply copy  them
 into subsequent semiannual compliance reports.  Furthermore, it
 is helpful to the permitting authority reviewing the compliance
 report to have that  information in each report.  Therefore,  the
 final rule retains the requirement to include a brief description
 of each process unit in each semiannual compliance report.

     Comment: Two commenters (IV-D-12, IV-D-13) requested  that
 the EPA delete the requirement to include in the semiannual
 compliance report a description of any changes in CMS, processes,
 or controls since the last reporting period.   The commenters
 stated that these changes require a Title V permit change, making
 the reporting of  them in the semiannual compliance report
 unnecessary.

     Response: The requirement to include in semiannual
 compliance reports a description of any changes in CMS,
processes,  or controls is not intended to replace a facility's
 obligation to modify its Title V permit when such a change
 occurs.  Rather,   it is meant to be helpful to the permitting
authority to have this information included in the semiannual
compliance report.  We do not believe that it is a significant
burden to report  this information on those occasions when  changes
have been made.

     Comment:  Two commenters (IV-D-12, IV-D-13) stated that  the
entries in Table  7 referring to §63.1(b)(3)  and §63.10(b)(3) of
 the General Provisions imply that every major source in the
United States must keep records stating that their facility  is
not an HCl production facility.   The commenters requested  that

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 the entry in the "Applies to Subpart NNNNN" column be changed
 from "yes" to "no" for the specified sections of the General
 Provisions in order to avoid imposing unnecessary recordkeeping
 requirements on a very large number of sources.

     Response:  We believe that the commenters'  interpretation of
 the requirement to keep records indicating that a facility is not
 subject to this subpart is incorrect.  It is not necessary that
 every facility in the country keep records stating that they are
 not subject to every published standard that does not apply to
 them.   Rather,  an owner or operator should apply a
 "reasonableness test" to determine whether to keep such records
 (e.g.,  a dry cleaning facility does not need to keep records
 indicating it is not subject to the Steel Pickling NESHAP).
 Furthermore,  the proposed revisions to the referenced sections of
 the General Provisions indicate that only sources in a particular
 source category need to keep records indicating that they are not
 subject to the relevant standards for that source category.

     The final rule for this source category,  in particular,
 includes complicated applicability provisions.   In many cases, it
will not be immediately obvious to an inspector or enforcement
official whether a particular facility is subject to this
subpart.  Therefore,  if an owner or operator determines that his
 facility,  which produces HCl,  is not subject to this subpart, it
is in his best interest to keep records indicating that the
facility is not subject.

     Comment:  Two commenters (IV-D-12,  IV-D-13)  requested that
the EPA delete the requirement to maintain a log detailing the
operation and maintenance of process and control equipment
between the compliance date and the time when CMS are installed
and validated and operating limits are established.   The
commenters stated that the requirement is too general and unclear
and serves no environmental purpose while exposing facilities to
an unknown compliance liability.  The commenters further stated
that keeping operating records that good practices are being
employed and compliance is being achieved has always been
adequate during that short time period and requested that the
requirement to keep a log be deleted.

     Response:  We agree with the commenters that the referenced
requirement is  not entirely clear as to what should be recorded
and what the associated liabilities are.  We have,  therefore,
decided to remove this requirement from the final rule.
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 2.6.4      Inconsistencies  in  Proposed Rule

     Comment:  One  commenter  (IV-D-06)  noted that  §63.9045(a)  is
 not  consistent with  Table  7,  particularly with  respect  to  section
 63.9(f)  of the General  Provisions.

     Response: Proposed §63.9045(a)  stated  that owners  or
 operators  must submit all  of  the  notifications  in, among others,
 §  63.9(b)  through  (h) of the  General  Provisions that  apply to
 them.  As  noted  in Table 7 of  the proposed  rule,  §63.9 (f)  does
 not  apply  to this  subpart  because it  pertains only to opacity and
 visible  emissions  standards,  which  are not  included in  the
 proposed rule.   We do not  consider  this  to  be an  inconsistency
 because  §63.9045(a)  clearly states  that  the owner or  operator
 only has to comply with those  sections that apply to  them,  and
 Table 7  specifies  which sections  of  the  General Provisions
 specifically apply to this subpart.

 2.6.5      Electronic Recordkeeping

     Comment:  Two  commenters  (IV-D-12,  IV-D-13) requested
 clarification  of the requirement  to maintain records  on-site  for
 at least two years following  the  date  of each report/event.   The
 commenters stated  that  many records are  now kept  in electronic
 format,  so the requirement should be  clarified  to indicate that
 records  must be  accessible from on-site  for at  least  two years.
 The  commenters cited the HON  (§63 . 103 (c) (1) ) as an example of a
 rule with  such a clarification.

     Response: We  agree with  the  commenters that  records required
 to be kept on-site may  be kept on-site in electronic  format
 (e.g.,  computer  files).  The  final rule has been  changed to
 reflect  this clarification.

 2.6.6     Report Addressee

     Comment:  One  commenter (IV-D-07)  asked to  whom the required
 reports  should be  addressed.  The commenter was unsure whether
 the EPA  or a State agency was  the appropriate recipient of  the
 reports.

     Response:  The appropriate recipient of  the reports required
under this subpart is either your permitting authority  (State,
 local,  or tribal agency, S/L/T) or,  if the  Administrator has  not
delegated authority to your S/L/T, the EPA.  As stated in
 §63.9070(a) of the proposed rule, an owner  or operator should
contact his EPA Regional Office to find out whether this subpart
has been delegated to his permitting authority.  An owner  or
operator  can determine which is the appropriate EPA Regional
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 Office  to contact by viewing the following webpage:
 http://www.epa.qov/epahome/locate2.htm.

 2.7   EMISSION ESTIMATES

      Comment: One commenter  (IV-D-09) stated that the EPA
 overestimated both the baseline emissions and the projected
 emission reductions.  The commenter stated that the EPA's
 misinterpretation of the data it collected regarding the
 commenters' facility contributed to the overestimated emission
 estimates.

      Response: We calculated the baseline emissions using HC1
 emission data from the Toxic Release Inventory,  primarily for the
 year  1998.  In the memorandum6  in  the docket  documenting our
 calculation of the baseline emissions, we stated that our
 estimate of the baseline emissions was possibly an overestimate
 because we used TRI data which did not indicate whether all of
 the HC1 emissions from a plant site came from the HCl production
 processes.   Because we used these baseline emissions to calculate
 the projected emission reductions from the proposed rule, the
 projected emission reductions could also be slightly
 overestimated.   However,  because the MACT floor regulatory
 alternative (which is the minimum level of stringency allowed by
 the Clean Air Act and is entirely technology-based) was selected,
 the estimate of projected emission reductions did not directly
 impact the decision.

     Therefore,  in the final rule,  we have not changed the
 assumptions and methodology used to calculate the baseline
 emissions and the projected emission reductions.  We have,
however, made specific changes to our emission estimates based on
 the details the commenter provided regarding the facility owned
by his company,  as documented in a memorandum in the docket.7   We
would point out that the commenter's situation is somewhat unique
as ownership of the facility has changed several times between
 the time represented by the permit data and the present, and the
processes that were previously all owned by the same corporation
are now divided among several companies.
     6 Memorandum.  Hartmann, A., and Norwood,  P.,  EC/R
Incorporated,  to Maxwell,  B.,  EPA/CG.   Baseline Conditions for
Hydrochloric Acid Production.   March 21,  2001. (Docket Item II-B-
5}

     7 Memorandum.  Deering, A., and Norwood,  P.,"  EC/R
Incorporated,  to Maxwell,  B.,  EPA/CG.   Baseline Conditions and
MACT Floor Impacts for the Final Hydrochloric Acid Production
NESHAP.  October 4, 2002 (Docket Item IV-B-4}

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2.8  COST IMPACTS

2.8.1     Assumption of Common Scrubber

     Comment: Several commenters  (IV-D-13, IV-D-14, IV-D-15, IV-
D-16, IV-D-18) stated that a key assumption that the EPA used in
calculating the cost impacts is invalid.  The EPA assumed that
facilities could control multiple emission streams using a single
control device,  thereby reducing control and monitoring costs.
The commenters stated that it is not feasible for most facilities
to use a common control device for all of their HCl production
emission streams because of the physical layouts of their
facilities and because of the long distances between emission
points.   Additionally,  the commenters noted that storage tanks
and transfer operations tend to emit higher concentrations of HCl
and be controlled with simpler control devices than process
vents, which would make combining these emissions streams
impractical.  The commenters also noted that safety concerns
often preclude the combination of multiple emission streams into
a single control device.  The commenters asserted that the EPA
grossly underestimated the cost impacts of the proposed rule
because each facility would need to install many control devices
and,  consequently,  many parameter monitoring systems.   The
commenters requested that the EPA gather more accurate data
concerning the number of control devices that each facility would
need to install  and then re-calculate the cost impacts.

     However, another commenter (IV-D-08) stated that routing all
of these emission points to a common control device is feasible
because the efficiency of the control device can be maximized by
matching it with the emission stream that has the highest
pollutant loading and the least variability (e.g.,  process vent
if included in common control device).   The commenter stated
that, for HCl production facilities,  the process vents typically
have the highest pollutant loading with the least variability,
storage tanks have typically have the lowest pollutant loading
with the most variability,  and transfer operations fall in
between.

     Response:  In response to another comment we received (see
section 2.1.1),  we have clarified that the final rule applies
only to HCl storage tanks that are directly related to the HCl
production unit.   This should mean that the distance between an
HCl process vent and associated storage tanks and transfer
operations is shorter than it would be were all HCl storage tanks
on-site to be included in the HCl production affected source,
making it more feasible to use a common control device.   In
response to the  comment that it would be difficult to combine
emission streams with different concentrations,  we point out
commenter IV-D-08's assertion that it is feasible to combine

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 emission  streams of varying concentrations if the control device
 is matched  to  the emission stream with the highest pollutant
 loading.  We acknowledge the comment that safety concerns are an
 issue  in  combining emission streams into one control device.

     We don't  agree entirely with all of the points raised by the
 commenters  and we continue to believe that there are situations
 in which  a  common control device would be possible and is, in
 fact,  used.  However, to be most conservative in estimating the
 potential impacts of this rule,  we have revised our estimate of
 the control costs for the final rule using the assumption that
 each emission  point that would need to be controlled would have
 its own dedicated control device installed.   This resulted in a
 total  estimated capital cost of $12.4 million and a total
 estimated annual cost of $5.9 million (total annualized control
 and monitoring capital cost of $1.4 million;  total annual
 equipment operation and maintenance cost of  $380,000; and total
 reporting and  recordkeeping cost of $4.2 million).   This
 represents an  increase of around $245,000 from the total annual
 cost estimated at proposal (see section IV.C.  of the proposal
 preamble).8

 2.8.2     Cost Not Justifiable

     Comment:  One commenter (IV-D-06)  stated that the true cost
 impacts of the proposed rule are too high given the small
 environmental benefit that would be achieved.   The commenter
 asserted that the cost impacts estimated by  the EPA are too low
 and estimated the total annual compliance cost for the proposed
 rule to be in excess of $1 million for the commenters'  company,
which owns several potentially subject facilities.   Since several
 of the facilities owned by the commenters'  company emit less than
 5 tons of  HCl  per year,  the commenter concluded that it does not
make sense to impose $250,000 worth of compliance costs (per
 facility)  to reduce only a few tons of emissions per year.

     However,  another commenter  (IV-D-05)  noted their support for
 the EPA's  decision to regulate HCl production facilities and
 stated that the cost to the industry is  justifiable considering
     lSNote that we revised our estimate of the cost for
individual control devices because we changed the emission
limitations in responses to comments received.  The control
efficiency required by the final rule is lower than the control
efficiency that was equivalent to the concentration emission
limitations proposed.   Therefore,  the cost for each control
device is lower in the final calculation of cost impacts than it
was in the proposed calculation of cost impacts.

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 the protection of human health  that would be  provided  if  the
 proposed  rule were implemented.

     Response: In accordance with  section 112(d)(3)  of  the  Clean
 Air Act,  we are required to establish emission  limitations  at
 least as  stringent as the MACT  floor.  The  emission  limitations
 in the proposed rule represent  the MACT  floor and we,  therefore,
 must impose limits at least as  stringent as this floor  level,
 without regard to the associated cost impacts.  In the
 consideration of alternatives more stringent  than this  floor
 level, we do consider the relative costs and  other impacts.
 Additionally, HCl production facilities  that  are located  at major
 source plant sites cannot be exempted from  the  rule, even if it
 is a low-emitting HCl production facility.

     The  commenter did not provide information  on their estimate
 of annual costs "in excess of $1 million,"  nor  did they provide
 detailed  comments on aspects of our cost impacts estimate.
 Therefore, we were not able to  address the  claim that our
 estimated impacts were too low.

     We have, however,  made several changes to  the final  rule
 that should serve to reduce the cost impacts  of the MACT  floor
 emission  limitations for low-emitting facilities and emission
 points.   For example,  in response to a comment  in section 2.1.1,
 we have revised the applicability to include  only those
 facilities that produce greater than or equal to 30 percent
 liquid HCl by weight,  thus eliminating the  possibility that
 producers of dilute HCl with little emission  potential are
 subject.  Also,  in response to  a comment we received (see section
 2.1.1),  we have clarified that  the final rule applies only to HCl
 storage tanks that are directly related to  the HCl production
 unit,  which means that small,  remote tanks would not be subject
 to control requirements.   Further,  in response  to another comment
 (see section 2.1.3),  we have added a size cutoff for storage
 tanks based on the cost-effectiveness of control.  In response to
 another comment received (see section 2.5.1),  we have eliminated
 the annual performance test requirement.   These measures  should
 reduce the number of emission points needing  control devices and
 the frequency of performance testing,  thereby reducing the cost
 impacts  of the final rule.   Since the commenter did not provide
 specific details as to which portions of the  cost impact  analysis
were underestimated,  we have not made any specific changes to the
 cost impact analysis in response to this comment.
                               2-78

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 2 .9  MISCELLANEOUS

 2.9.1     ASTM Method Changes

     Comment: One commenter  (IV-D-01) informed the EPA that the
 ASTM test methods cited in the proposal preamble do not have the
 most current dates listed.  The commenter provided the correct
 method names and dates.  These corrections are presented in Table
 2-5 .

          Table 2-5.  Corrected ASTM Test Method Names.
Method Name Listed
in FR Notice
D3154-91
D3796-90 (1996)
E337-84 (1996)
D3464-96
Corrected Method
Names
D3154-00
D3796-90(1998)
same
D3464-96(2001)
The commenter explained that methods D 3796,  E 337,  and D 3464
have been reapproved without changes, but method D 3154 has
changed.  If requested, the commenter stated that they would
provide the EPA with a copy of the current version of the
recently-revised Method D 3154 with the rationale for the
changes.

     Response:  These methods were cited in section VI.H of the
proposal preamble as voluntary consensus standards potentially
applicable to the proposed rule.   All four of the methods
mentioned by the commenter were determined to be impractical
alternatives to EPA test methods for the purposes of the proposed
rule.   We have,  however, changed the method names in the final
preamble to reflect the most current version of the ASTM methods
cited.
2.9.2
Word Changes
     Comment:  Two commenters (IV-D-13, IV-D-16)  requested that
the word "scrubber" in the right-hand column of Table 3, item #1
be changed to "control device,  if any."  The commenters stated
that this change would address situations in which an alternate
control device is used or no control device is needed to meet the
standard.
     Response:  We have made the requested change in the final
rule.
                               2-79

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     Comment: Two commenters  (IV-D-13, IV-D-16) requested  that
 the term  "major alternatives" be changed to  "major changes"  in
 §63.9070  of the proposed rule.  The commenters stated that  this
 change would be consistent with the language in §63.90.

     Response:  We have made the requested change in the  final
 rule.

     Comment: Two commenters  (IV-D-13, IV-D-16) stated that  the
 word "immediate" in §63.9050 (f) is unnecessary and should be
 deleted.  The commenters noted that paragraphs (1) and  (2)  of
 that section detail the timing for submission of the reports,
 making the word "immediate" inappropriate.

     Response:  The term "immediate startup, shutdown,  and
 malfunction report" is used in §63.10(d)(5) of the General
 Provisions to distinguish it from a "periodic startup, shutdown,
 and malfunction report."  An immediate SSM report is submitted
 within the specified time period after an SSM event for which  the
 procedures in the SSM plan were not followed.  A periodic SSM
 report is submitted semiannually for SSM events for which the  SSM
 plan was  followed.   Therefore, in order to be consistent with  the
 General Provisions and retain this distinction, we have not
 removed the word "immediate" from the final rule.

 2.9.3      Typographical Errors

     Comment:  Commenters provided the following comments
 regarding typographical errors in the proposed rule.

     One commenter (IV-D-16) noted that the reference to
 "paragraphs (f)(l)  through  (3) of this section" in §63.9005(e)
 appears erroneous.   The commenter suggested that the reference
 should be to paragraphs (e)(1) through (3)  of that section,  which
 appear to be more germane than paragraphs (f) (1)  through (3) .

     Two commenters (IV-D-13,  IV-D-16) noted that §63.9005(f)
 refers to "paragraphs (g)(1) through  (3)  of this section," which
do not exist.   The commenters suggested that the EPA intended  to
refer  to paragraphs (f)(1)  through (3) of that section.

     One commenter (IV-D-13) noted that §63.9025 (e)  referred to
in §63.9035 (c)  does not exist.  The commenter stated that the
reference should be to §63.9025(d)  instead.

    Two commenters (IV-D-13,  IV-D-16) noted that the word
 "following" in  the heading of the right-hand column of Table 4
appears to be out of place and should be  deleted.
                               2-80

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     Three commenters  (IV-D-13, IV-D-16,  IV-D-22) noted that  the
word "austic" in the left-hand column of Table 4, item #1 should
be corrected to "caustic."

     Two commenters  (IV-D-13, IV-D-16) noted an inconsistency
between Table 1 and Tables 4 and 5.  Items #1 and 2 of Table  4
and items #la and 2a of Table 5 read "is less than the
concentration limit specified in Table 1 . . , " while Table 1 reads
"...concentration shall not exceed..."  The commenters requested
that the EPA add the words "equal to or" before "less than" in
the specified sections of Tables 4 and 5.

     One commenter (IV-D-16)  noted that the entry for item #3 in
the right-hand column of Table 4 should begin with the word
"you. "

     Response:  We have made all of the corrections in the final
rule.

     Comment:  Two commenters (IV-D-13, IV-D-16)  noted that the
reference in §63.9005 (f) (1)  to §63.9030 appears erroneous.  The
reference in §63.9005 (f) (1)  says "Ongoing  operation and
maintenance procedures in accordance with  ... 63.9030."  However,
§63.9030 presents initial compliance requirements.

     Response:  We have changed §63.9005(f) (1) to reference
§63.9025 instead of §63.9030.

2.9.4      Subpart A Comments

     Comment:  One commenter  (IV-D-19)  submitted a copy of his
comments regarding the proposed revisions  to the General
Provisions in Subpart A.  The commenter requested that these
comments be considered in this rulemaking  because the proposed
HC1 production NESHAP relies heavily on the General Provisions.
The commenter highlighted two of his comments regarding the
proposed General Provisions:  (1)  EPA should delete the sections
from which  MACT standards have been consistently exempted,  and
(2)  some of the compliance requirements (e.g.,  immediate
reporting of SSM events, CMS downtime calculations,  and
submission of SSM plan revisions)  are beyond what is necessary to
demonstrate compliance.  The commenter encouraged the EPA to
promulgate the revised General Provisions  in order to allow
industry to determine the interaction between the proposed rule
and the revised General Provisions.

     Response:  We appreciate the additional comments.  These
comments are being considered under the General Provisions
rulemaking.
                               2-81

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                                     TECHNICAL REPORT DATA
                                (Please read Instructioitf on reverse hcforc < oinpl
  l REPORT NO
    EPA-453/R-03-004
                                                                     RI c'ii'ii:NT'.s \cc rssioN NO
  4 TITLI, AND SUBTITEI
  National Emission Standards for Hazardous Air Pollutants
  (NESHAP) for the Hydrochloric Acid Production Industry:
  Summary of Public Comments and Responses
                  * RI I'ORT D'\T1
                  January 2003
                   I'l RI ORMINCi OR(i.\M7.\T1ON C (11)1
  1 AUTHOR(S)
                                                                     PLKI()KMIN(iOR(,.\NI/'\TION REPORT NO
  ') PERFORMING ORGANIZATION NAME AND ADDRESS
    Emission Standards Division
    Office of Air Quality Planning and Standards
    U.S. Environmental Protection Agency
    Research Triangle Park, NC 2771 1
                                                                    10 PROGRAM ELEMENT NO
                  I I  CONTRACT/GRANT NO

                    68-D-01-055
  12 SPONSORINC; AGENCY NAME AND ADDRESS
    Director
    Office of Air Quality Planning and Standards
    Office of Air and Radiation
    U.S. Environmental Protection Agency
    Research Triangle Park, NC 2771 1	
                                                                    M TYPE ()l RI-PORT AND PFKIODCOV! RFD
                  U SPONSORING AGI'NCY CODI
                  EPA/200/04
    SUPPLEMENTARY NOTES
  This document contains a summary of public comments received on the NESHAP for Hydrochloric-
  Acid Production (40 CFR 63. subpart  NNNNN). which was proposed on September  18. 2001 (66 FR
  48174). This document also provides the EPA's response to each comment, and outlines the changes
  made to the regulation in response  to public comments.
                                       KEY WORDS AND DOCUMENT ANALYSIS
                    DESCRIPTORS
                                                  h IDLNT1IILRS/OPEN ENDED TERMS
                                                                                      L COSAT1 1'iekl/GuHlp
 Air pollution
 Hazardous air pollutants
 Emission reduction
 Hydrochloric acid production
Air Pollution control
 IS DISTRIBUTION STATEMENT

   Release Unlimited
!') SECURITY C LASS (Hci»nii
  Unclassified
21 NO OI PAGES
       94
                                                  20 SI ( I'RITY ( I -\SS !/'
                                                    Unclassified
Kl'\ l-(.rni222(l-l (Ki'%.4-77)    PR1 VIOL'S I DITION IS OHSOLETI

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