United States Office of Air Quality EPA-453/R-98-011

Environmental Protection Planning and Standards May 1999

Agency Research Triangle Park, NC 27711

Air

NATIONAL EMISSION STANDARDS FOR

HAZARDOUS AIR POLLUTANTS (NESHAP)

FOR PESTICIDE ACTIVE INGREDIENT

PRODUCTION:

SUMMARY OF PUBLIC COMMENTS AND

RESPONSES

EPA-453/R-98-011

National Emission Standards for Hazardous Air Pollutants 

(NESHAP) For Pesticide Active Ingredient Production

Background Information for Promulgated Standards--

Summary of Public Comments and Responses

Emission Standards Division

U. S. Environmental Protection Agency

Office of Air and Radiation

Office of Air Quality Planning and Standards

Research Triangle Park, North Carolina 27711

May 1999
ii

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 non-profit

organizations--as supplies permit--from the Library Services Office (MD-35), U. S.

Environmental Protection Agency, Research Triangle Park, North Carolina 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).
iii

ENVIRONMENTAL PROTECTION AGENCY

National Emission Standards for Hazardous Air Pollutants for

Pesticide Active Ingredient Production--

Summary of Public Comments and Responses

1. The final National Emission Standards for Hazardous Air Pollutants

(NESHAP) will regulate emissions of hazardous air pollutants from

pesticide active ingredient production. 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. For additional information contact:

Mr. Lalit C. Banker

Organic Chemicals Group (MD-13)

U. S. Environmental Protection Agency

Research Triangle Park, NC 27711

Telephone: (919) 541-5420

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

National Technical Information Service (NTIS)

5285 Port Royal Road

Springfield, VA 22161

Telephone: (703) 487-4650

U. S. EPA Library Services Office (MD-35)

U. S. Environmental Protection Agency

Research Triangle Park, NC 27711

Telephone: (919) 541-2777

4. Electronic copies of this document may be obtained from the EPA

Technology Transfer Network (TTN) over the internet by going to either

of the following addresses:

http://www.epa.gov/ttn/oarpg/t3bid.html

http://www.epa.gov/ttn/uatw/pest/pestpg.html
iv
v

TABLE OF CONTENTS

Page

LIST OF ACRONYMS AND ABBREVIATIONS FOR UNITS OF MEASURE ..... xi

1.0 SUMMARY ...................................................... 1-1

1.1 SUMMARY OF CHANGES SINCE PROPOSAL ................... 1-1

1.2 SUMMARY OF IMPACTS OF PROMULGATED REGULATIONS .... 1-4

2.0 OVERVIEW OF PUBLIC COMMENTS ............................... 2-1

2.1 ORGANIZATION OF COMMENT SUMMARIES .................. 2-1

3.0 APPLICABILITY .................................................. 3-1

3.1 SELECTION OF SOURCE CATEGORY .......................... 3-1

3.2 DEFINITION OF AFFECTED SOURCE .......................... 3-9

3.3 APPLICABILITY TO PRODUCTION OF INTERMEDIATES ......... 3-18

3.4 RECOVERY DEVICES ........................................ 3-20

3.5 EXEMPTIONS FROM THE RULE .............................. 3-21

3.6 NEW AFFECTED SOURCE .................................... 3-25

3.7 STARTUP, SHUTDOWN, AND MALFUNCTION .................. 3-27

3.8 OVERLAP WITH OTHER REGULATIONS ....................... 3-29

3.9 STORAGE TANK ASSIGNMENT ............................... 3-30

4.0 COMPLIANCE DATES ............................................. 4-1

4.1 EXISTING SOURCES ......................................... 4-1

4.2 NEW SOURCES ............................................. 4-1

5.0 DEFINITIONS .................................................... 5-1

5.1 NEW TERMS DEFINED IN THE FINAL RULE .................... 5-1

5.2 REVISED DEFINITIONS THAT DIFFER FROM COMMENTERS 

SUGGESTIONS .............................................. 5-2

5.3 REVISED DEFINITIONS CONSISTENT WITH COMMENTERS 

SUGGESTIONS .............................................. 5-9

5.4 DEFINITIONS UNCHANGED SINCE PROPOSAL ................. 5-11

6.0 STANDARDS-GENERAL ........................................... 6-1

6.1 HEAT EXCHANGERS ........................................ 6-1

6.2 OUTLET CONCENTRATION STANDARDS ...................... 6-2

6.3 COMPLIANCE OPTIONS ..................................... 6-4

6.4 ROUTINE MAINTENANCE ................................... 6-5

6.5 MACT AND MACT FLOOR ................................... 6-6

6.6 CLARIFICATION ............................................ 6-8
TABLE OF CONTENTS (continued)

Page

vi

7.0 STANDARDS-PROCESS VENTS .................................... 7-1

7.1 MACT AND MACT FLOOR ................................... 7-1

7.2 APPLICABILITY CUTOFFS ................................... 7-4

7.3 HCL STANDARDS ........................................... 7-7

7.4 COMPLIANCE AVERAGING PERIOD .......................... 7-9

7.5 OVERLAP WITH OTHER STANDARDS ......................... 7-10

7.6 CLARIFICATIONS ........................................... 7-10

7.7 REQUIREMENTS FOR SURGE CONTROL VESSELS AND 

BOTTOMS RECEIVERS ...................................... 7-11

8.0 STANDARDS-STORAGE TANKS ................................... 8-1

8.1 STORAGE TANK MACT FLOOR ............................... 8-1

8.2 STORAGE TANK STANDARD ................................. 8-3

8.2.1 Applicability Cutoffs .................................... 8-3

8.2.2 Control Level of the Standard ............................. 8-4

8.2.3 Format of the Standard ................................... 8-5

8.3 COMPLIANCE AVERAGING PERIOD .......................... 8-5

8.4 STORAGE TANK DEFINITION ................................ 8-6

8.5 OVERLAP WITH OTHER STANDARDS ......................... 8-7

8.6 CLARIFICATIONS ........................................... 8-7

9.0 STANDARDS FOR EQUIPMENT LEAKS ............................. 9-1

9.1 LEVEL OF THE STANDARD .................................. 9-1

9.2 CROSS-REFERENCING THE CONSOLIDATED AIR RULE ......... 9-8

10.0 STANDARDS FOR WASTEWATER .................................. 10-1

10.1 GENERAL .................................................. 10-1

10.2 AFFECTED WASTEWATER ................................... 10-1

10.3 TREATMENT OPTIONS ...................................... 10-5

10.4 STANDARDS FOR NEW SOURCES ............................ 10-6

10.5 OVERLAP WITH OTHER REGULATIONS ....................... 10-8

10.6 CLARIFICATION OF CROSS-REFERENCES ..................... 10-9

11.0 STANDARDS FOR BAG DUMPS AND PRODUCT DRYERS ............. 11-1

11.1 JUSTIFICATION FOR THE STANDARDS ........................ 11-1

11.2 LEVEL OF THE STANDARD .................................. 11-3
TABLE OF CONTENTS (continued)

Page

vii

12.0 POLLUTION PREVENTION STANDARD ............................. 12-1

12.1 FORMAT OF THE STANDARD ................................ 12-1

12.2 POLLUTION PREVENTION FOR REACTANTS AND 

GENERATED HAP ........................................... 12-4

12.3 COMPLIANCE PROCEDURES ................................. 12-6

12.4 RECORDKEEPING ........................................... 12-7

12.5 BASELINE YEAR ............................................ 12-7

13.0 EMISSION AVERAGING ........................................... 13-1

13.1 COMPLEXITY OF METHODOLOGY ........................... 13-1

13.2 RESTRICTIONS ON EMISSIONS AVERAGING ................... 13-1

14.0 TESTING PROVISIONS ............................................ 14-1

14.1 TESTING CONDITIONS ...................................... 14-1

14.2 TEST PLAN ................................................. 14-6

14.3 EMISSION PROFILE ......................................... 14-6

14.4 TEST DURATION ............................................ 14-7

14.5 CLARIFICATIONS ........................................... 14-7

15.0 INITIAL COMPLIANCE DEMONSTRATIONS ......................... 15-1

15.1 GENERAL .................................................. 15-1

15.2 INITIAL COMPLIANCE WITH PROCESS VENT STANDARDS ..... 15-6

15.2.1 Emission Estimation Calculations .......................... 15-6

15.2.2 Compliance with Outlet TOC Limit ......................... 15-10

15.2.3 Exemption from Performance Testing ....................... 15-11

15.2.4 Provisions for Flares ..................................... 15-14

15.2.5 Provisions for Condensers ................................ 15-14

15.2.6 Clarifications .......................................... 15-16

15.3 INITIAL COMPLIANCE WITH STORAGE TANK STANDARDS ..... 15-17

15.4 INITIAL COMPLIANCE WITH WASTEWATER STANDARDS ...... 15-19

15.5 PLANNED ROUTINE MAINTENANCE .......................... 15-19
TABLE OF CONTENTS (continued)

Page

viii

16.0 MONITORING .................................................... 16-1

16.1 IMPACT OF MONITORING REQUIREMENTS ON CONTROL 

LEVELS .................................................... 16-1

16.2 ESTABLISHING PARAMETER LEVELS ......................... 16-3

16.3 MONITORING FOR SPECIFIC CONTROL DEVICES .............. 16-7

16.3.1 Bag Dumps and Product Dryers ............................ 16-7

16.3.2 Flares ................................................ 16-9

16.4 MONITORING FREQUENCY .................................. 16-10

16.5 QUALITY CONTROL PROGRAM AND PERFORMANCE 

EVALUATIONS OF CONTINUOUS MONITORING SYSTEMS ...... 16-11

16.6 MONITORING DURING STARTUP, SHUTDOWN, AND 

MALFUNCTION ............................................. 16-12

16.7 MONITORING FOR STORAGE VESSEL CONTROLS .............. 16-13

16.8 DATA AVAILABILITY REQUIREMENTS ....................... 16-15

16.9 VIOLATIONS ............................................... 16-15

16.10 MISCELLANEOUS ........................................... 16-19

16.11 EDITORIAL CLARIFICATIONS ................................ 16-21

17.0 RECORDKEEPING ................................................ 17-1

17.1 RECORDKEEPING BURDEN .................................. 17-1

17.2 RECORDS OF GROUP 1 DETERMINATIONS .................... 17-2

17.3 RECORDS OF TURNOVERS .................................. 17-3

17.4 RECORDS OF PROCESS VENT EMISSIONS ..................... 17-3

17.5 RECORDS OF WASTEWATER CHARACTERISTICS .............. 17-4

17.6 RECORDS OF BAG LEAK DETECTION ALARMS ................ 17-5

17.7 LOCATION OF RECORDS .................................... 17-5

17.8 OVERLAP WITH RCRA RECORDKEEPING REQUIREMENTS ..... 17-6

17.9 CLARIFICATIONS ........................................... 17-6

18.0 REPORTING ..................................................... 18-1

18.1 PRECOMPLIANCE REPORT .................................. 18-1

18.2 PERIODIC REPORTS ......................................... 18-2

18.3 NOTIFICATION OF COMPLIANCE STATUS REPORT ............. 18-3

18.4 STARTUP, SHUTDOWN, AND MALFUNCTION REPORTS ........ 18-3

18.5 NOTIFICATION OF PROCESS CHANGE ........................ 18-4

18.6 EQUIPMENT LEAK REPORTS ................................. 18-5

18.7 RECORDS OF REPORTS ...................................... 18-5

18.8 OVERLAP WITH RCRA REPORTING REQUIREMENTS ........... 18-6
TABLE OF CONTENTS (continued)

Page

ix

19.0 IMPACTS 19-1

19.1 ENVIRONMENTAL IMPACTS ................................. 19-1

19.2 COST IMPACTS ............................................. 19-1

19.3 ECONOMIC IMPACTS ....................................... 19-3

20.0 MISCELLANEOUS ................................................ 20-1

20.1 STANDARDS FOR ENDOCRINE DISRUPTORS .................. 20-1

20.2 RISK-BASED STANDARD FOR HCl ............................ 20-1

20.3 RELATIONSHIP BETWEEN THIS RULE AND OTHER RULES ...... 20-2

20.4 RELATIONSHIP BETWEEN THE NOTIFICATION OF 

COMPLIANCE STATUS REPORT AND TITLE V PERMITS ........ 20-4

20.5 OMB REVIEW .............................................. 20-4

20.6 EDITORIAL CLARIFICATIONS ................................ 20-4

20.7 COMMENT PERIOD ......................................... 20-5

20.8 SUPPORTIVE COMMENTS ................................... 20-5

LIST OF TABLES

2-1. LIST OF COMMENTERS ON THE PROPOSED NESHAP 

FOR THE PAI INDUSTRY .......................................... 2-2

20-1. EDITORIAL COMMENTS AND RESPONSES .......................... 20-6
x
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LIST OF ACRONYMS AND ABBREVIATIONS FOR UNITS OF MEASURE

ACRONYMS

ACPA American Crop Protection Association

Act Clean Air Act

ACT Alternative Control Techniques

Administrator EPA Administrator

Agency EPA

ALR average leak rate

ANSI American National Standards Institute

APCD air pollution control device(s)

BACT best available control technology

BIF boilers and industrial furnaces

CAA Clean Air Act

CAM compliance assurance monitoring

CAR Consolidated Air Rule

CEM continuous emissions monitor

CEMS continuous emissions monitoring system(s)

CFR Code of Federal Regulations

Cl2 chlorine

CMPU chemical manufacturing process unit

CMS continuous monitoring systems

CO2 carbon dioxide

CTG Control Techniques Guideline

CWA Clean Water Act

EG emission guidelines

EPA U. S. Environmental Protection Agency

FBCA fixed-bed carbon adsorber

FDA Food and Drug Administration

FID Flame Ionization Detector

FIFRA Federal Insecticide Fungicide and Rodenticide Act

Frfraction removed

FR Federal Register

GMP Good Manufacturing Practice

H2 hydrogen

HAP hazardous air pollutant(s)
xii

HCl hydrogen chloride

HCN hydrogen cyanide

HON Hazardous Organic NESHAP

IFR internal floating roof

LDAR leak detection and repair

MACT maximum available control technology

MON Miscellaneous Organic NESHAP

N2 nitrogen

NAAQS National Ambient Air Quality Standards

NAICS North American Industrial Classification System

NESHAP national emission standards for hazardous air pollutants

NO2 nitrogen dioxide

NOCS notification of compliance status

NO nitrogen oxides x

NPDES National Pollutant Discharge Elimination System

NSM new source MACT

NSPS new source performance standards

NSR new source review

O2 oxygen

OAQPS Office of Air Quality Planning and Standards

OECA Office of Enforcement and Compliance Asurance

OMB Office of Management and Budget

OSHA Occupational Safety and Health Administration

OVA Organic Vapor Analyzer

P&R Polymers and Resins

P2 pollution prevention

PAI pesticide active ingredient

PEC purchased equipment costs

PhRMA Pharmaceutical Research and Manufacturers of America

PM particulate matter

PMPV Pharmaceutical Manufacturing Process Unit

POD point of determination

POTW Publicly - Owned Treatment Works

PSD prevention of significant deterioration

QA/QC quality assurance/quality control

QIP Quality Improvement Program
xiii

R&D research and development

RACT Reasonably Available Control Technology

RCRA Resource Conservation and Recovery Act

SARA/TRI Superfund Amendments and Reauthorization Act/Toxic Release Inventory

SIC Standard Industrial Classification

SO2sulfur dioxide

SOCMI Synthetic Organic Chemical Manufacturing Industry

SO sulfur oxides x

TOC total organic compounds

TRE total resource effectiveness

TRI toxic release inventory

TSCA Toxic Substances Control Act

USDA United States Department of Agriculture

VOC volatile organic compounds
xiv

ABBREVIATIONS FOR UNITS OF MEASURE

Btu = British thermal unit

CE = degrees Celsius

dscf = dry standard cubic foot (@ 14.7 psia, 68EF)

dscfm = dry standard cubic foot per minute (@ 14.7 psia, 68EF)

dscm = dry standard cubic meter (@ 14.7 psia, 68EF)

EF = degrees Fahrenheit

ft = cubic feet 3

gal = gallon

gr = grains

hr = hour

K = degrees Kelvin

kg/yr = kilograms per year

km = kilometer

Kpa = kilopascals

L = liter

L/yr = liter per year

lb = pound

m = cubic meter 3

min = minute

mg = milligrams (10 grams) -3

Mg = megagram (10 grams) 6

MMm = million cubic meters 3

MW = megawatt

MW-hr/yr = megawatt-hours per year

ng = nanogram (10 grams) -9

ppm = parts per million

ppmdv = parts per million by dry volume

ppmv = parts per million by volume

ppmw = parts per million by weight

psia = pounds per square inch actual

scmm = standard cubic meters per minute

ton/yr = ton per year

μg = microgram (10 grams) -6

μm = microns

wk = week

yr = year
1-1

1.0 SUMMARY

On November 10, 1997, the U. S. Environmental Protection Agency (EPA) proposed

national emission standards for hazardous air pollutants (NESHAP) for pesticide active

ingredient (PAI) production (63 FR 60565) under authority of Section 112 of the Clean Air Act

(Act). Public comments were received from 34 sources consisting mainly of PAI manufacturers,

trade associations, and other interested parties. 

All of the comments that were submitted and the responses to these comments are

summarized in this document. This summary is the basis for the revisions made to the standards

between proposal and promulgation. 

1.1 SUMMARY OF CHANGES SINCE PROPOSAL

Applicability

Eliminated applicability of inorganic PAI’s.

Introduced concept of “process units” and “PAI process units” analogous to the

definitions in other regulations.

Introduced concept of “process unit groups” and “primary product determinations” for

defining applicability of PAI process units that are constructed from nondedicated equipment that

are also used to produce non-PAI products.

Added provisions regarding overlap with other standards.

Process vent standards

Added 20 parts per million by volume (ppmv) option for HCl/Cl halide emissions. 2

Changed control requirement for HCl/Cl at new sources from 99.9 percent to 99 percent. 2
1-2

Added an alternative standard that requires control to 20 ppmv as TOC and 20 ppmv as

HCl/Cl , and compliance is demonstrated using CEM’s. 2

Storage vessel standards

Changed MACT floor and MACT cutoff from pounds per year (lb/yr) format to vapor

pressure cutoff.

New source cutoff changed from 1 lb/yr and 7,000 gallons (gal) to 16.5 kilopascals (kPa)

and 10,000 gal, and control requirement changed from 98 to 95 percent.

Clarified that allowance for planned routine maintenance of control devices applies only

to control devices used for storage vessels.

Final rule allows owner or operator to designate storage vessels as Group 1 storage

vessels.

Added alternative standard option like the one for process vents.

Wastewater standards

Changed definition of wastewater to exclude maintenance wastewater streams with low

emission potential.

Added exception to the cross-referenced provisions in the Hazardous Organic NESHAP

(HON) to allow compliance only with outlet total organic compounds (TOC), not both outlet

TOC and total organic hazardous air pollutant(s) (HAP).

Equipment leaks

Changed requirements to be consistent with provisions in the proposed Consolidated Air

Rule (CAR) instead of subpart H; the provisions have been included in the final rule.

Pollution prevention

Changed basis for baseline factor from 1 year of data to 3 years.

Added equation to calculate required reduction in volatile organic compounds (VOC)

factor.
1-3

Added requirement to submit a demonstration summary describing methods to be used to

measure and record consumption and production.

Test methods and initial compliance

Revised requirement to correct outlet concentrations to 3 percent oxygen only when using

a combustion device and supplemental gases are combined with the vent stream. Also added

requirement to correct outlet concentrations when supplemental gases are combined with vent

streams that are controlled in non-combustion devices.

Deleted option to demonstrate compliance for a condenser based on test results; final rule

requires compliance based on temperature measurement and calculation of the emissions. As a

result, also deleted peak-case conditions based on maximum heat removal capacity.

Deleted option to test under representative peak-case conditions.

Expanded definition of peak-case conditions to include most challenging conditions other

than maximum HAP load. Also expanded definition of the emissions profile to include

equipment limitations as well as actual emissions.

Added optional equations to calculate emissions from heating and depressurization.

Changed the cutoff for calculating incremental values for emissions from heating from

50 degrees Kelvin (K) below the boiling point of the material in the vessel to 10 K below the

boiling point.

Added equations for calculating emissions from gas evolution and air drying.

Added equations for calculating controlled emissions from condensers when uncontrolled

emissions are generated from one of the seven types of emission episodes for which equations

are specified in the rule.

Added provisions for demonstrating initial compliance when using a flare.

Monitoring

Added monitoring parameters for catalytic incinerators.
1-4

Changed monitoring provisions for bag leak detectors by allowing adjustments after

initial settings under certain conditions and deleting the requirement to develop a Quality

Improvement Program (QIP).

Clarified that averaging periods for batch unit operations may be over a “block” period

not to exceed the duration of the operation or series of operations as well as over 24 hours.

Reporting

Changed submittal date of Precompliance report from 12 months to 6 months before the

compliance date.

Added procedures for submitting notification when the owner or operator wants to

change anything that was (or would have been) submitted for approval in the Precompliance

report.

Miscellaneous

Numerous editorial changes and changes in definitions to improve readability and clarify

intent, especially in the monitoring, recordkeeping, and reporting sections. 

1.2 SUMMARY OF IMPACTS OF PROMULGATED REGULATIONS

The final standards will reduce nationwide emissions of HAP from the production of

PAI’s by 2,500 megagrams per year (Mg/yr) (2,800 tons per year [ton/yr]), or 65 percent

compared to baseline emissions that would result in the absence of the standards. Wastewater

generated from water scrubbers used to control hydrogen chloride (HCl) emissions is expected to

increase by an estimated 10.8 million liters per year. No increase in solid waste is expected. 

Energy usage is expected to increase by an estimated 4,880 x 10 British thermal units (Btu) per 9

year. The total annual costs for control at existing and new sources are estimated to be

approximately $37.5 million and $5.16 million, respectively (June 1995 dollars). The economic

impact analysis shows that the market price will increase by less than 3 percent, and market

output will decrease by less than 3 percent. No plant closures are expected from compliance with

the final standards.
2-1

2.0 OVERVIEW OF PUBLIC COMMENTS

The public comment period following the November 10, 1997 Federal Register notice

(proposed rule) lasted from November 10, 1997 to January 9, 1998. However, a number of

commenters requested that the comment period be extended, and EPA did grant an extension of

the comment period until February 9, 1998. Late comments received after February 9, 1998 were

also accepted. A total of 34 letters commenting on the proposed rule were submitted and these

comments have been placed in the docket for this rulemaking (Docket A-95-20) under

categories IV-D (received on or before February 9, 1998) and IV-G (received after February 9,

1998). Table 2-1 presents a listing of all persons submitting written comments on the proposed

rule, their affiliations, and the recorded docket item number assigned to their correspondence. 

In some instances, commenters supported their comments by referencing comments

submitted by other comments. This was particularly true of the comments submitted by the

American Crop Protection Association (ACPA) which were referenced several times by their

member companies. Commenters IV-D-20, IV-D-22, IV-D-25, and IV-D-29 incorporated the

comments of the ACPA (comment letter IV-D-16) by reference.

2.1 ORGANIZATION OF COMMENT SUMMARIES

Chapters 3.0 through 20.0 present a summary of the comments on the proposed rule along

with EPA responses. The comments are grouped by subject areas, and the organization of topics

is similar to the organization of the preamble to the final rule.
2-2

TABLE 2-1. LIST OF COMMENTERS ON THE PROPOSED NESHAP 

FOR THE PAI INDUSTRY

Item No. Commenter and Affiliation

IV-D-01 D.Gustafson, The Dow Chemical Company

IV-D-02 L. Hott, Novartis Crop Protection, Inc.

IV-D-03 W. Dickerson, BASF

IV-D-04 T. Gilding, American Crop Protection Association

IV-D-05 A. Stungys, Tomen Agro, Inc.

IV-D-06 A. Deshmukh, Occidental Chemical Corporation

IV-D-07 V. Jones Clorox Company

IV-D-08 T. Gilding, American Crop Protection Association

IV-D-09 J. Cooper, AlliedSignal, Inc.

IV-D-10 B. Higgins, STAPPA/ALAPCO

IV-D-11 R. Godbole, Phelps Dodge Corp.

IV-D-12 D. Ailor, Coke and Coal Chemicals Institute

IV-D-13 W. Adams, Kennecott Utah Copper Corp.

IV-D-14 R. Phelps, Eastman Chemical Company

IV-D-15 A. Stungys, TomenAgro, Inc.

IV-D-16 T. Gilding, American Crop Protection Association

IV-D-17 M. Wax, Institute of Clean Air Companies

IV-D-18 D. McKinnon, Manufacturers of Emission Controls Association

IV-D-19 K. Parameswaran, ASARCO, Inc.

IV-D-20 R. DiMenna Rohm and Haas, Co.

IV-D-21 J. Dumelow, DuPont Agricultural Products

IV-D-22 B. Raff, Novartis Crop Protection, Inc.

IV-D-23 C. Wysong, Engelhard Corp. 

IV-D-24 R. Pauline, Chemical Specialties Manufacturers Association

IV-D-25 C. Keffer, Monsanto Company

IV-D-26 S. Tirey, Chemical Manufacturers Association

IV-D-27 A. Dawson, American Cyanamid Co.

IV-D-28 L. Swaim, The Dow Chemical Company

IV-D-29 J. Dege, Dupont SHE Excellence Center

IV-G-01 D. Powers, Merck & Co., In.c

IV-G-02 R. Smerko, The Chlorine Institute

IV-G-03 N. Carlson, Elf Atochem

IV-G-04 A. Deshmukh, Occidental Chemical Corporation

IV-G-05 R. Randolph, Missouri Department of Natural Resources

IV-G-06 C. Wysong, Engelhard Corporation
3-1

3.0 APPLICABILITY

3.1 SELECTION OF SOURCE CATEGORY

Status at proposal: Under the proposed rule, the source category consisted of the

production of all pesticide active ingredients that are used to produce an insecticide, herbicide, or

fungicide pesticide end-use product. The preamble to the proposed rule explained how the

source category was developed, and requested comment on the scope of the source category. The

procedure used to develop the source category is summarized in the remainder of this

introduction.

The initial list of categories of major and area sources included 10 source categories in

the agricultural chemicals industry group. In June 1996, butadiene furfural cotrimer was moved

from the polymers and resins industry group to the agricultural chemicals industry group (61 FR

28197). In the notice of proposed rulemaking, EPA made the following additional changes: 

(1) all manufacturers of active ingredients within the meaning of FIFRA section 2(a) that are

used in herbicide, insecticide, or fungicide pesticide end-use products were added to the

agricultural chemicals industry group; (2) the individual initial and new source categories in the

agricultural chemicals industry group were combined into a single source category; and (3) the

new source category was named “pesticide active ingredient production.”

Comment: Thirteen commenters addressed the issue of the source category definition. 

Four commenters discussed the scope of the source category in general terms:

commenters IV-D-09 and IV-D-12 opposed the expansion, commenter IV-D-28 could not tell

from the available information whether or not it was appropriate, and commenter IV-D-20

supports the scope of the applicability and the definition of PAI. Eight commenters (IV-D-07,

IV-D-11, IV-D-13, IV-D-19, IV-D-23, IV-D-24, IV-G-02, and IV-G-04) requested exemptions
3-2

for specific processes or classes of processes that would be subject to the proposed rule; the

primary concern of these commenters was that the proposed rule would apply to inorganic PAI

production processes, many of which, the commenters contend, are significantly different than

organic PAI production processes. One commenter (IV-D-15) stated that the Captan process

(one of the original source categories) should not be combined with other PAI processes because

it is significantly different from other PAI processes. Details of the comments are described in

the remainder of this section.

Commenters IV-D-09 and IV-D-12 opposed the expansion of the source category because

(1) the processes subject to the proposed rule are dissimilar in that some are from naturally

occurring materials, but others are synthetically produced and (2) many of the processes produce

compounds that are not primarily used in insecticide, herbicide, or fungicide products. 

Commenter IV-D-09 is also concerned that the change has been largely undetected or

misunderstood by the regulated community because the proposal did not identify either the

number of processes that would be covered or examples of the processes. Without reviewing the

processes to ensure that process operation, emission characteristics, control device applicability,

and costs are similar, the commenters contend that the proposed regulation is arbitrary and

capricious, is inconsistent with the Act and EPA’s procedures for developing maximum available

control technology (MACT) standards, and defeats the purpose for creating industry categories. 

Both commenters suggested that EPA change the definition of PAI to mean any synthetically

produced material because the Basis and Purpose document only describes processes to

synthetically produce chemicals. Commenter IV-D-09 noted that this approach would be

consistent with the definition of intermediate, which is a compound produced in a chemical

reaction and that is further processed in one or more additional chemical reactions to produce a

PAI. Both commenters also indicated that previous rulemakings recognize this distinction (e.g.,

the HON, the new source performance standards (NSPS) for equipment leaks, and the Effluent

Guidelines for Pesticide Chemicals all focus on processes to synthetically produce compounds;

whereas the Effluent Guidelines for Gum and Wood Chemicals target production of compounds

from natural sources). Commenter IV-D-12 also noted that the Effluent Guidelines are explicit

and unambiguous in that each process subject to the guidelines is specified.
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One commenter (IV-D-28) stated that the Federal Register notice itself did not contain

enough information about the similarities and differences of the processes that would be covered;

therefore, the commenter could not determine whether it is appropriate to combine the source

categories. However, this commenter stated that, for this rulemaking, EPA should not further

expand the source category beyond the processes covered by the proposed rule because owners

and operators of other processes may not have read the preamble closely enough to determine

that EPA is thinking about adding other processes. Also, this commenter contended that the

necessary data to evaluate such processes could not be provided in the comment period. This

commenter also specifically supported the exclusion of antimicrobials, rodenticides, and biocides

from the definition of PAI.

Commenter IV-D-24 believes the proposed rule is too broad because it does not

distinguish between antimicrobial PAI’s and other types of PAI’s. The commenter requested that

EPA exempt formulators of antimicrobial PAI’s for the following reasons: (1) production,

pollution prevention, and treatment practices for antimicrobial PAI processes are different from

other PAI processes; (2) the antimicrobial PAI’s have low toxicity, biodegrade rapidly, and have

undergone extensive safety testing; (3) EPA recognized the unique nature of sodium hypochlorite

and similar chemicals by excluding them from the Effluent Guidelines for Formulating,

Packaging, and Repackaging Facilities in the Pesticide Chemical Category; and (4) formulators

of antimicrobial products have no air emissions.

Commenter IV-G-02 requested that EPA exempt chlorine and sodium hypochlorite

production and packaging plants from the rule because chlorine is already highly regulated. The

commenter cited Occupational Safety and Health Administration (OSHA) regulations, Superfund

Amendments and Reauthorization Act/Toxic Release Inventory (SARA/TRI) reporting

requirements, EPA’s pending risk management program requirements for facilities with more

than 2,500 pounds (lb) of chlorine onsite, and the pending MACT standards for chlor-alkali

production. Another commenter (IV-D-07) also requested that EPA exempt sodium hypochlorite

production because the product: (1) does not present an unreasonable risk to the environment;

(2) is not emitted to the air in the manufacturing process; (3) ionizes, dissolves rapidly in water,

rapidly degrades, and does not volatilize; (4) the production, pollution prevention, and treatment
3-4

practices differ from these practices for other PAI’s, which EPA recognized by excluding it from

the Effluent Guidelines for the Pesticide Chemicals Category.

Commenter IV-D-23 requested that EPA exempt kaolin (aluminum silicate) production

because: (1) the process, which consists primarily of mechanical action and treatment with

inorganic chemicals, is very different from the flow diagram in the Basis and Purpose document;

(2) the commenter’s production facility is not a major source of HAP emissions; (3) kaolin is not

a typical pesticide in that it repels pests rather than killing them; and (4) kaolin is nontoxic (i.e., it

has an unlimited tolerance level).

Commenters IV-D-11, IV-D-13, and IV-D-19 believe sulfuric acid production should be

exempt from the rule. All of the commenters operate copper smelters and produce sulfuric acid

from the sulfur dioxide in the smelter offgas. These processes would be subject to the proposed

rule because the sulfuric acid is registered as a herbicide, but only small amounts of it are sold for

this use. (The commenters noted that other sulfuric acid producers also would be subject to the

proposed rule, although their sulfur dioxide feedgas is produced by burning sulfur.) 

Commenter IV-D-13 explained that the smelter offgas contains various metals and metal

compounds, some of which are HAP. These HAP are removed by particulate controls prior to

the catalytic oxidation of the sulfur dioxide to sulfur trioxide. The commenter cited EPA’s final

summary report for the primary copper smelters NESHAP, which stated that the particulate

controls result in HAP metal control efficiencies of greater than 99.9 percent, and, in most cases,

the combined emissions of all HAP metals in acid plant tail gases are less than 0.1 ton/yr. 

Commenter IV-D-13 also cited the following reasons to support an exemption: (1) the process

does not use or generate organic HAP or HCl, which are the major HAP according to the

preamble to the proposed rule; (2) sulfuric acid plants are an effective control for metal HAP

emissions from smelters; (3) regulating the process would provide no environmental benefit but

would impose a significant burden (e.g., to demonstrate that equipment does not emit HAP);

(4) EPA lacks authority under section 112(c) of the Act to apply NESHAP to sulfuric acid plants

because the plants are not major sources and the de minimis emissions would not present a threat

of adverse effects warranting regulation of area sources; (5) most sulfuric acid manufacturers do

not think of the process as a PAI process, which may lead to noncompliance due to ignorance;
3-5

and (6) the production process, emissions, and controls differ from the original 11 processes. 

Commenter IV-D-19 provided similar reasons: (1) the preamble to the proposed rule indicates

the rule is designed for organics and HCl, but no mention is made of other commodity

inorganics; (2) no information in the docket supports a PAI NESHAP for sulfuric acid plants;

and (3) the final NESHAP for copper and lead smelter furnaces will indicate that sulfuric acid

plants are MACT. Furthermore, both commenter IV-D-13 and commenter IV-D-19 indicated

that sulfuric acid plants are not included on the list of source categories, and commenter IV-D-13

believes that if it were listed at all, it logically would be listed among the categories of inorganic

chemicals, not with agricultural chemicals. Commenter IV-D-11 concurred with the comments

submitted by commenter IV-D-13.

Commenter IV-D-11 requested that copper sulfate production be exempted from the rule. 

The commenter explained that copper sulfate is a byproduct from liquors used at copper

refineries and rod mills, and it is registered as a herbicide. To support the request for an

exemption, the commenter used arguments similar to those used to support the request for an

exemption of sulfuric acid production: (1) the process is not a major source of HAP (but it may

be co-located at a site that is a major source); (2) the process emits no more than trace amounts of

organic HAP and HCl, the major HAP emitted from the source category according to the

preamble to the proposed rule; (3) the rule would not achieve an environmental benefit but would

impose a significant compliance burden on owners and operators to show they are below cutoffs;

(4) owners and operators do not think of their processes primarily as PAI processes, which is

likely to lead to noncompliance due to ignorance; and (5) this process and organic PAI processes

do not have similar process operations, emission characteristics, control device applicability and

cost, and opportunities for pollution prevention. As an alternative to adding an exemption for

this process, the commenter suggested that EPA could limit the applicability of the rule to the

manufacturing of organic PAI’s.

Commenter IV-D-15 believes the Captan process (one of the initial source categories)

should not be combined with other PAI processes because it has properties and process

requirements that make it different from other PAI processes. The commenter contends that the

impacts of combining the processes in one source category were not considered when drafting
3-6

the proposed rule, and the commenter suggested that EPA study the impact of grouping these

processes. According to the commenter, some of the differences are: (1) the process vent flow

rate for production of the intermediate is much lower than the process vent flow rate for the

active ingredient production, which leads to differences in the complexity and cost of the control

devices; (2) the Captan process has both volatile organic HAP and particulate HAP emissions;

(3) the cost to control carbon disulfide emissions from the active ingredient production would be

much higher than the modeled costs (see section 19.2 for additional discussion of the cost

impacts).

Commenter IV-G-04 stated that EPA should exempt chromic acid and sodium

bichromate processes from the rule because these processes were part of the Chrome Chemicals

source category, which EPA delisted.

Commenter IV-G-05 supports the addition of PAI’s such as organochlorides and

organophosphates because these compounds are bioaccumulative, persistent, and acutely toxic.

Response: In response to the comments, EPA reexamined the scope of the source

category and determined that the proposed rule included some processes that are not similar to

the others. For the final rule, changes were made to narrow the scope of the source category; in

addition, for processes that remain in the source category, changes have been made to exempt

some processes and to clarify requirements for others. These changes are: (1) a statement has

been added to specify that the provisions of the rule apply only to PAI process units that

“process, use, or produce HAP;” (2) the definition of PAI has been changed to mean any organic

material that is an active ingredient within the meaning of FIFRA section 2(a); and (3) a

statement has been added to specify that the rule does not apply to the production of ethylene

(processes subject to the HON are also exempted, as they were in the proposed rule).. Finally,

EPA decided not to limit the source category only to production of compounds by chemical

synthesis. Each of these decisions is discussed in more detail later in this response. However,

this discussion first summarizes EPA’s rationale for expanding the source category list to include

PAI’s other than those on the initial source category list, and for aggregating them all together in

a single source category; this rationale was presented in the preamble to the proposed rule.
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From a survey of a subset of the industry, EPA determined that: (1) production of

compounds on the initial source category list as well as many other compounds have a number of

similarities, including process equipment, emission characteristics, control applicability, and

control costs; (2) many of the additional compounds also are produced at facilities that are major

sources; and (3) the initial compounds and the additional compounds are PAI’s that are used in

herbicides, insecticides, and fungicides. Because common control techniques can be applied,

EPA concluded that developing separate standards for each PAI is not warranted and that it is

technically feasible to regulate emissions from a variety of PAI processes by a single set of

emission standards. Variability in the quantity of HAP produced by different processes was

addressed by incorporating applicability thresholds in the standards (section VI.D describes

changes that have been made to the thresholds for storage vessels in the final rule). At the

facilities that produce more than one PAI, often in the same equipment or same “pool” of

equipment, compliance would be facilitated by having only a single set of emission standards. 

Finally, it would be more efficient and less costly for EPA to develop only a single set of

emission standards, and compliance and enforcement activities by regulatory authorities would

be more efficient and less costly.

The provision that the rule applies only to PAI process units that “process, use, or

produce HAP” has been added to the final rule because EPA did not intend for owners and

operators to demonstrate compliance for processes that do not meet this condition. Note,

however, that this provision does not automatically exempt process units that do not emit HAP;

for emission points in such process units, an owner or operator must demonstrate that emissions

are less than the applicability thresholds.

The EPA decided to exclude production of inorganic compounds from the source

category because (1) inorganic PAI’s comprise only a small percentage of the total PAI

production, (2) many of the inorganic PAI production processes do not use or emit HAP, (3) data

are unavailable on the use, emissions, and control of HAP compounds other than organics and

HCl, (4) some of the inorganic PAI’s are included in other active or delisted source categories,

and (5) most of the inorganic PAI’s are used primarily for non pesticidal purposes. In this

context, “organic” means any compound that contains carbon and hydrogen with or without other
3-8

elements. Based on a review of pesticide registration data in 1996, less than 10 percent of the

PAI’s in pesticide products that are registered as insecticides, herbicides, or fungicides are

inorganic compounds. Inorganic compounds comprise a similar percentage by weight; based on

1993 consumption data, the top 25 compounds account for nearly half of the total PAI

production, and the two inorganic compounds in the group (sulfur and copper hydroxide) account

for less than 10 percent of the total.

Of the inorganic PAI processes, only those producing HCl, chlorine, and compounds

containing arsenic and chromium are known to use and emit HAP. Both HCl and chlorine

production processes have been specifically exempted from the final rule because they are the

subject of other MACT standards that are under development. Chromium-based compounds are

part of the delisted chrome chemicals source category and thus, EPA agrees with the commenter

that they should not also be part of the PAI source category. Data on the existing control levels

for arsenic-based compounds are unavailable. In the absence of such data, EPA has decided that

production of such compounds should not be part of the PAI source category, but they may be

investigated at a later date.

The commenters cited examples of some inorganic compounds that are primarily used for

nonpesticidal purposes. The EPA believes there are other inorganic compounds that could be

added to this list of compounds used only in minor amounts as pesticides. Conversely, most of

the organic compounds are specifically designed as PAI’s. Exceptions include ethylene, which

has been specifically exempted in the final rule because it is the subject of a MACT standard that

is under development, and several compounds covered by the HON such as acrolein, ethylene

oxide, napthalene, and propylene glycol.

Production of organic PAI compounds that are derived from natural materials is retained

in the source category. Natural materials used as PAI’s fall into one of two categories. One

category includes herbs, tobacco dust, dried blood, chitin, putrescent whole egg solids, pyrethrum

flowers, cinnamon, sawdust, and ground sesame plant. These compounds are simply harvested

or collected and the only processing involves mechanical action. None of these compounds is a

HAP. As a result, these processes are not subject to the final rule because the production

processes do not process, use, or produce HAP. The second category includes compounds like
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turpentine that are extracted from natural materials. Extraction processes are not exempted from

the final rule because they tend to use large amounts of solvent and have a high potential for

emissions. Emissions from extraction processes tend to be more concentrated than emissions

from many of the operations in chemical synthesis processes, and they tend to be larger scale

operations than extraction operations that are part of a chemical synthesis process. These

characteristics make control of extraction processes more cost effective than control of many

chemical synthesis processes. However, because the final rule includes a primary use criterion

for determining applicability (see the response to comment 2 in section 3.2), extraction processes

are only subject to the final rule if the product is primarily used as a PAI.

The EPA disagrees with the assertion by one commenter that the Captan® process (and

the associated intermediate process) should be considered separately from other PAI processes. 

The intermediate appears to be an integral intermediate and thus, would be subject to the rule as a

separate process. Although the flow rates of the intermediate and Captan® process vent streams

differ, the flow rates and other process vent stream characteristics for both processes are well

within the range of characteristics for process vent streams at other surveyed PAI facilities. 

These differences were accounted for in EPA’s impact analysis by using different models to

represent the two processes.

In addition, the particulate emissions from product dryerss also are considered to be a

separate type of emission point like process vents or storage vessels. The fact that this plant is

the only one of the MACT floor facilities to have HAP emissions from product dryers is not

considered a significantly unique characteristic. It is analogous to the fact that some of the other

plants have HAP storage tank emissions or wastewater discharges and are subject to the specific

standards for these emission points, where other plants are not.

Finally, EPA believes the cost analysis is correct. Carbon disulfide can be controlled with

many of the same control devices that are used to control other organic HAP. If incinerated, the

resulting sulfur oxides (SO2) emissions can be controlled using scrubbers comparable to those

used to control HCl emissions. A detailed discussion of the cost analysis is presented in section

19.2. Therefore, EPA believes the Captan process is not sufficiently different from other PAI

processes to warrant development of a subcategory or a separate source category.
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3.2 DEFINITION OF AFFECTED SOURCE

Status at proposal: Section 63.1360(a) of the proposed rule defines the affected source as

the facility-wide collection of process vents, storage tanks, waste management units, heat

exchange systems, cooling towers, equipment identified in § 63.149, and equipment components

(pumps, compressors, agitators, pressure release devices, sampling connection systems, openended valves or lines, valves, connectors, and instrumentation systems) in PAI manufacturing

operations at a major source of HAP emissions. The EPA received several comments on the

affected source. The comments focused on the following issues: (1) limiting applicability to

processes where the primary product is a PAI, (2) limiting applicability to processes where the

product is primarily used as a PAI, and (3) clarifying the definition of affected source. 

Clarification of the definition of the affected source is addressed in responses to comments in this

section; changes to the definitions of terms used in the definition of the affected source are

discussed in chapter 5.

Comment 1: Commenter IV-G-03 requested clarification of the definition of the affected

source to ensure that only those processes and equipment associated with the processes that

produce a PAI are affected. The commenter believes the clarification is necessary because the

phrase “facility-wide” in the definition could be interpreted to mean that all emission points,

whether or not they are associated with a PAI process, are subject to the rule.

Response: Although the definition of the affected source in the proposed rule was

described in a very long sentence, the EPA believes that it clearly indicated that “facility-wide”

applied specifically to process equipment that are used to produce PAI’s. However, to improve

clarity and reduce redundancy, the affected source in the final rule is defined to be the “PAI

process units” that process, use, or produce HAP, and that are located at a plant site that is a

major source. The final rule also indicates that an affected source includes waste management

units, heat exchange systems, and cooling towers that are associated with the PAI process units. 

As noted in the response to comment 4 in this section, most of the language in the proposed

definition of the affected source has been shifted to the definition of the new term “PAI process

unit” in the final rule.
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Comment 2: Two commenters (IV-D-14 and IV-D-28) urged EPA to specify, as in other

MACT standards, that a process or process unit is subject to the rule only if its primary product is

a PAI. Commenter IV-D-14 defined primary product as the one with the greatest annual design

capacity on a mass basis. According to this commenter, a primary product determination is

needed because much process equipment that is only occasionally used for PAI production could

be subject to the proposed rule, and the exemption for equipment operating in HAP service for

less than 300 hours per year (hr/yr) is likely too low to exempt many processes. Commenter

IV-D-28 stated that in cases where a single process unit makes more than one product, the

concept of “primary product” helps the manufacturer determine which rules apply. This

commenter cited three situations where a primary product determination is important. The first is

in contract manufacturing, where the process unit is reconfigured as needed to switch from one

product to another (the frequency of reconfiguration may be variable--months, a year, or even

longer). If a PAI is produced for only a short time during the year, the commenter believes it

would not be appropriate for the process unit to be subject to the PAI rule. The commenter also

noted that a simple way to define applicability is to specify that if a process unit stops making a

PAI, the PAI rule no longer applies. The second situation involves processes that make two or

more products at the same time (one is the main reason the process was built; the others are

incidental, beneficial by-products). By identifying the primary product, the process unit would

be regulated together with other process units that produce that product under a specific,

appropriate MACT standard. The third situation is when a facility makes a change in the process

unit that is intended to be permanent. The commenter could not find any provision in the

proposed rule that would allow such a process unit to be exempt from the rule if they stop

making a PAI.

Another commenter interpreted the proposed rule to mean that the rule would apply

whenever a PAI is produced. If a facility uses non-dedicated equipment, the commenter realized

that this could mean that other rules would apply when the equipment was reconfigured to

produce a different product (e.g., the proposed pharmaceuticals rule used the same language). 

The commenter believes that complying with two standards for the same equipment would be

confusing. Therefore, the commenter suggested that the PAI rule apply only when 50 percent or

more of the annual production from the equipment is a PAI, or that EPA allow a facility to
3-12

comply only with the most stringent rule that would apply to the equipment, regardless of the

configuration or the product being produced.

Response: In response to the comments EPA evaluated several options for including a

primary product determination. The analysis considered two types of situations. The first

situation consists of processing equipment that produces only one PAI, produces different PAI’s

at different times, or simultaneously produces coproducts (one of which is a PAI). In each of

these, PAI is produced to some degree with each operation of the equipment. The second

situation involves processing equipment that produces different products periodically, and some

of the products are not PAI’s.

For the first situation EPA determined that a primary product determination is not needed. 

This conclusion is obvious for equipment that only produces PAI’s because no other rule could

apply, provided that compounds subject to the HON are exempted from this regulation. The

analysis is more complicated if a PAI is produced as a byproduct or is produced in minor

quantities relative to some other product of the process. The EPA is not aware of any such

situations. However, if such processes exist, they may already be subject to the HON, in which

case they are exempted under § 63.1360(d) of the final rule. The only other standard that might

apply to such a process in the future is the Miscellaneous Organic NESHAP (MON). The MON

will cover a wide variety of compounds in many different industries. Thus, EPA believes that a

process unit producing a PAI, even if the PAI is not the primary product, has more in common

with other PAI process units than with process units that will be subject to the MON. Therefore,

EPA also believes it is more appropriate to regulate all such process units under the PAI rule

rather than the MON.

The EPA considered four options for defining the applicability of the rule to equipment

periodically used to produce chemicals other than PAI’s. The first option is no change from

proposal (i.e., no primary product determination). The second option is to include all equipment

used to produce different products in a “process unit group,” and always comply with the

regulation that applies to the primary product for the group, regardless of what product is being

produced. The third option is to define the applicability of the rule based on the primary product

of the process unit. The fourth option is similar to the second option, except that the applicable
3-13

rule for the process unit could, under certain circumstances, be a rule other than the one for the

primary product of the group.

Under option 1, there is no primary product determination, and the standards apply to

each PAI process unit. Equipment used to produce multiple products is part of a PAI process

unit whenever it is producing a PAI. This option was rejected because, as the commenters noted,

it has the undesirable effect of requiring an owner or operator to comply with a different

regulation each time the feedstock changes or the equipment is reconfigured to make a different

type of product.

The second option is to lump all nondedicated equipment into one or more “process unit

groups” and require the owner or operator to comply with the rule that applies to the primary

product within the group. A variation on this option would be to require compliance at all times

with the most stringent regulation that would apply to any of the individual process units within

the group. This option was rejected because the promulgated pharmaceuticals standard does not

include a provision that would allow an owner or operator to elect to comply with the final PAI

rule when a pharmaceutical is produced in a process unit group that has a PAI for the primary

product. The variation also was rejected because it would be difficult to implement; the most

stringent regulation would vary depending on the mix of different types of emission points at a

given facility and could require mixing and matching different requirements from different rules

that apply to the various emission points.

The third option would specify that the rule apply only if the primary product of the

process unit is a PAI. This option was rejected because it does not solve the problem of

equipment being subject to multiple regulations. A process unit is defined only by the product it

makes. If the raw materials are changed or the equipment is reconfigured to make a different

product, the result is a different process unit. An exemption for a process unit when it no longer

produces a PAI would be meaningless because, by definition, a change in product creates a

different process unit. In other words, it is not possible to make a permanent change in the

primary product of a process unit because the change creates a different process unit. The

process unit is based on the product being produced, not a specific collection of equipment.
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The fourth option, like the second option, includes the concept of process unit groups. 

Under this option, the owner or operator may elect to comply with another existing MACT

standard for any PAI process unit(s) if the primary product of the process unit group is subject to

the other standard on the promulgation date of the PAI rule or the date of startup of the process

unit group, whichever is later. Thus, PAI process units within a group, even if the PAI is not the

primary product for the group, are subject to this standard unless and until the process unit group

is subject to another MACT standard that covers the primary product of the group. This option

also allows the owner or operator to elect to comply with the pharmaceuticals standard for any

PAI process unit(s) if any of the products produced in the process unit group are subject to the

pharmaceuticals standard. Thus, pharmaceutical manufacturing process units within a group that

are covered by the pharmaceuticals MACT may comply with those standards even if a PAI is the

primary product of the group. This provision is included because the pharmaceuticals rule does

not have a provision that would allow an owner or operator to comply with the PAI rule while

producing a pharmaceutical product when the primary product of the group is a PAI. However,

two provisions in the pharmaceuticals rule are not applicable when producing a PAI. First, the

process vent emission limit of 0.15 Mg/yr in the PAI rule applies instead of the 2,000 lb/yr limit

in the pharmaceuticals rule because the 2,000 lb/yr cutoff would not be consistent with the

MACT floor for PAI process vents. Second, the owner or operator of a new source that will

produce PAI’s as well as pharmaceuticals must comply with all of the requirements regarding

application for approval of construction or reconstruction in § 63.5 of the General Provisions; the

exclusions in § 63.1259(a)(5) of the pharmaceuticals rule do not apply. Again, EPA believes this

change is necessary to avoid disparate treatment of PAI producers.

Under option 4, the primary product of a group is defined as the product (e.g., a PAI,

pharmaceutical, HON chemical, or currently unregulated chemical) with the highest estimated

operating time or total production rate for the 5 years after the compliance date for the PAI rule

or after startup of the process unit group, whichever is later. The owner or operator proposes the

number of groups and the boundaries of each group based on site-specific operation, but a group

may only include equipment that is or may be used with equipment that is used to produce a PAI

(i.e., some equipment must overlap between the PAI process unit and some other process unit for

all equipment in both process units to be part of the same group). This option was selected
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because it simplifies compliance by allowing an owner or operator to comply with only one

regulation for a process unit group. It accomplishes this goal without sacrificing emission

reductions because the requirements of the rules are similar. It also does not require that an

existing regulation be amended.

Clarification of the 300 hour exemption that one of the commenter’s cited is also needed. 

This exemption does not apply to process units; it applies to pumps, valves, and other

“equipment” that are subject to the equipment leak provisions in subpart H. This provision has

been clarified in the final rule.

Comment 3: Commenter IV-D-09 found the definition of the affected source to be

confusing and ambiguous regarding substances that are only occasionally produced for PAI use

or are not normally used as PAI’s. For example, many chemicals that are registered active

ingredients also have many other uses. According to the commenter, the rule should clarify that

production of a chemical exclusively for nonpesticidal purposes is not subject to the rule. The

commenter also noted that for some chemicals that are registered PAI’s only a small percentage

of the total quantity produced is sold for use as a PAI. Therefore, the commenter stated that the

rule should be clarified to restrict applicability to production of chemicals that are primarily

intended to be used as PAI’s. Another commenter (IV-D-12) also believes the rule should not

apply to processes producing compounds that are not primarily used as PAI’s.

Response: Since proposal, EPA has evaluated four options for determining applicability

of process units that produce a product for use both as a PAI and other purposes. Option 1 is to

require no primary use determination (i.e., no change from proposal). Option 2 is to list in the

rule compounds that are registered as PAI’s but that would not be subject to the rule based on

determinations that their primary use nationwide is not as a PAI. Option 3 is to require sitespecific determinations of primary use. Option 4 is to list in the rule all PAI’s that are subject to

the rule.

Option 1 would encompass the most process units and would therefore achieve the

greatest environmental benefit. The EPA rejected this option, however, because it could result in

inequitable regulatory treatment of a given type of process unit. For example, one facility might

produce a compound for multiple purposes, including a small amount for use as a PAI, but other
3-16

facilities produce the same compound exclusively for other purposes. Under this option, only the

facility producing a small amount of the compound for use as a PAI would be subject to the rule

even though otherwise identical to the other facility.

Under option 4, a list of PAI’s subject to the regulation would be included in the

regulation. Compounds for which the primary use is the collective non-PAI purposes would be

excluded from the list. This option was rejected because it would not accommodate changes in

the industry. This is a dynamic industry with new compounds being developed and registered as

PAI’s every year. Between 1984 and 1995, the industry added an average of 14 new compounds

per year (although not all of these new compounds would meet the definition of organic PAI

subject to regulation under this rule). As a result, updating the list every year would be

impractical. Another disadvantage to this option is that EPA’s pesticide reregistration process is

not yet complete. Presumably compounds with incomplete evaluations would be included on the

list. The list then would have to be amended periodically to delete compounds whose

registrations are canceled.

Option 2 was rejected because, like option 4, it would not automatically accommodate

changes in the industry; the rule might have to be amended periodically to exempt new

compounds that are primarily used for non-PAI purposes. Another concern with option 2 is that

it would be difficult to ensure that the list is accurate and complete.

The final rule adopts option 3, which requires site-specific determinations of primary use. 

This option was selected for several reasons. First, this approach is likely to result in a given

process being subject to only one, most appropriate regulation because EPA is not aware of any

compounds for which the primary use is as a PAI for one facility but not others. Furthermore,

EPA does not expect the primary use at a given facility to vary. However, if the primary use

changes to non-PAI purposes, the PAI final rule will still apply to the process unit (based on

EPA’s “once-in, always-in” policy); if the primary use changes to a PAI, the PAI final rule will

apply only if the process unit is not already subject to the HON. A second advantage of this

option is that it automatically accommodates new compounds that are developed in the future,

and existing compounds that are found to have a pesticidal application. A third advantage is that

minimal additional recordkeeping and reporting is required. Manufacturers are required under
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FIFRA to record and report the annual production of each PAI that they produce; today’s final

rule requires that they also record and report the total production to demonstrate that the

compound is produced primarily for non-PAI purposes. Finally, the pharmaceuticals rule

provides a recent precedent for including a primary use provision.

The final rule incorporates the primary use concept in the definition of PAI process unit. 

Specifically, a process unit is considered to be a PAI process unit if more than 50 percent of the

material produced is used as a PAI or integral intermediate. The primary use is determined based

on the projected annual production from the process unit in the three years after the effective date

of this rule or startup, whichever is later.

Comment 4: Commenter IV-D-28 believes the definition of affected source needs to be

revised to include not only the emission points, but also the process unit and emission control

technologies. The commenter recognizes that the definition in the proposed rule is similar to the

definitions in other MACT standards, but the commenter has recently realized that it is too

narrow. For example, in determining whether changes constitute “reconstruction,” the changes

must cost more than half as much as building a new similar affected source. However, under the

proposed rule, the affected source includes only process vents, not the reactors, distillation units,

or other process equipment of which the vent is a part. Similarly, it includes valves and

connectors on process piping, but not the piping itself. The commenter also contended that the

cost of installing emission controls is a legitimate part of the cost of building a new affected

source, but to consider that cost in the reconstruction analysis, emission control technologies

must be included in the definition of the affected source.

Response: Reconstruction, as defined in the General Provisions, includes: “the

replacement of components of an affected . . . source to such an extent that . . . the fixed capital

cost of the new components exceeds 50 percent of the fixed capital cost that would be required to

construct a comparable new source . . .”

The EPA agrees with the commenter that the equipment and piping within a process are

components of an affected source that should be considered in the fixed capital cost analysis for

determining whether changes constitute reconstruction. For this and other reasons, the final rule

includes the term “PAI process unit,” which is defined as the process, any associated storage
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tanks, equipment identified in § 63.149, piping and ducts, and components such as pumps,

compressors, agitators, pressure relief devices, sampling connection systems, open-ended valves

or lines, valves, connectors, and instrumentation systems that are used in the production of a PAI

or integral intermediate.

The EPA disagrees with the commenter’s assertion that control devices should be a

component of an affected source for the purposes of determining reconstruction costs. The

preamble to the General Provisions cites EPA’s policy on this issue, which was originally stated

in the preamble to a December 16, 1975 regulation that deals with modification, notification, and

reconstruction requirements under 40 Code of Federal Regulations (CFR) part 60. That

preamble states: “Costs associated with the purchase and installation of air pollution control

equipment (e.g., baghouses, electrostatic precipitators, scrubbers, etc.) are not considered in

estimating the fixed capital cost of a comparable entirely new facility unless that control

equipment is required as part of the process (e.g., product recovery).”

Comment 5: Commenter IV-D-28 supports the statement on page 60571 of the preamble

that the rule only applies to facilities that use, produce, or emit HAP.

Response: The EPA does not know where the commenter found this statement; it is not

on page 60571, nor is it anywhere else in the preamble to the proposed rule. However, EPA

agrees with the commenter that the rule should not apply to facilities, or process units within

facilities, that do not use or produce HAP. Process units that use or produce HAP but do not

emit it are not automatically excluded because EPA believes a facility must demonstrate that the

HAP is not emitted or that the emissions are below the appropriate applicability cutoffs. 

Therefore, the applicability section of the final rule has been revised to specify that the rule

applies to PAI process units that process, use, or produce HAP.

Comment 6: Commenter IV-D-24 expressed concern that the proposed 25,000 pound

production threshold could lead to unequal treatment of companies with one large facility as

opposed to several small facilities.

Response: The Clean Air Act requires that EPA develop standards for major sources

(i.e., stationary source located within a contiguous area and under common control that emits or

has the potential to emit considering controls, in the aggregate, 10 tons/yr or more of any HAP or
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25 tons/yr or more of any combination of HAP). The EPA interprets this definition to mean that

all emissions from the plant site are to be included when determining whether a source is a major

source. Small facilities (i.e., area sources) are to be regulated only if the emissions from those

facilities are determined to pose a threat of adverse effects to human health or the environment or

if otherwise listed under section 112(c).

3.3 APPLICABILITY TO PRODUCTION OF INTERMEDIATES

Status at proposal: Under § 63.1360(a) of the proposed rule, PAI manufacturing

operations would include manufacturing of any intermediate that is integral to a PAI production

process and for which more than 50 percent of the annual production of the intermediate is used

in the onsite production of PAI’s. An integral intermediate process was defined as a process

manufacturing an intermediate that is used in the onsite production of PAI’s and is not removed

to storage before being used to produce the PAI(s). An intermediate was defined as a compound

produced in a chemical reaction that is further processed or modified in one or more additional

chemical reactions to produce a PAI. Section 63.1360(h) of the proposed rule also would allow

an owner or operator to elect to include other intermediate processes in the affected source. The

other intermediates included (1) integral intermediates for which less than 50 percent of the

intermediate is used in the onsite production of PAI’s, and (2) isolated intermediates (i.e.,

intermediates that are removed to storage before being used in the onsite production of PAI’s).

Comment: Two commenters (IV-D-16 and IV-D-25) addressed the issue of including the

production of intermediates in the affected source. Commenter IV-D-25 supported the provision

that would allow an owner or operator the option of including production of isolated

intermediates under the PAI rule because the commenter produces intermediates that would be

subject to the Miscellaneous Organic NESHAP, but with this option the commenter may avoid

the complexity of complying with two NESHAP. Commenter IV-D-16 recommended

clarifications to §§ 63.1360(a) and (h) of the proposed rule. To improve the clarity of

§ 63.1360(a), the commenter recommended replacing the phrase “that is integral to a PAI

production process” with “that meets the definition of integral intermediate process.” The

commenter also recommended replacing the word “and” in § 63.1360(h) with “or” to clarify that

either or both of the two listed types of intermediates manufacturing operations may be included;
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according to the commenter, the language in the proposed rule could be interpreted to mean that

the option may be used only if both types are included. Another commenter (IV-D-28) stated

that the term “isolated intermediate” should not be used because it has a different meaning under

Toxic Substances Control Act (TSCA), and different definitions for a single term will cause

confusion. Another commenter (IV-D-15) stated that the rule needs to include a definition for

“storage” to clarify which intermediate processes are integral.

Response: The intent of the proposed rule was to consider each integral intermediate

process to be a separate process within the affected source, and to allow the owner or operator to

elect to include any other intermediate process in the affected source. To improve the clarity of

these provisions, EPA made several changes in the final rule. The first change was to include the

production of integral intermediates in the definition of the new term “PAI process unit,” as

described in section 3.2 of this chapter. This change clarifies that production of each integral

intermediate is a separate process unit. The second change was to delete the term “isolated

intermediate” to eliminate possible confusion with the term as it is defined under TSCA. The

impact of this change was minimal because the term was only used in the proposed rule to

describe intermediates that are not integral intermediates. The third change was to replace the

term “integral intermediate process” with the term “integral intermediate” and change the

definition to mean an intermediate for which 50 percent or more of the annual production is used

in the on-site production of one or more PAI’s and is not stored before being used in the

production of another integral intermediate or the PAI(s). For the purposes of this definition, an

intermediate is stored if it is discharged to a storage vessel and at least one of the following

conditions is met: (1) the processing equipment that discharges to the vessel is shutdown before

the processing equipment that withdraws from the vessel is started up; (2) on average, the

material is stored in the vessel for at least 30 days before being used to make a PAI; or (3) the

processing equipment that discharges to the vessel is located in a separate building or processing

area of the plant than the processing equipment that uses material from the vessel as a feedstock,

and control equipment is not shared by the two processing areas. Processes that satisfy any of

these conditions are considered to be significantly distinct and separate. The fourth change was

to clarify the provisions allowing the owner or operator to elect to include any intermediate

process in the affected source. The final rule specifies that an owner or operator may elect to
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designate production of any intermediate that does not meet the definition of integral

intermediate (and is not otherwise exempted) as a PAI process unit in the affected source. See

chapter 7 for a discussion of integral intermediates in the development of the MACT floor.

3.4 RECOVERY DEVICES

Comment : Commenter IV-G-03 requested that EPA clarify the applicability of

equipment that is used for multiple processes when the recovered material from a PAI process is

used in a non-PAI process. The commenter noted that § 63.1360(f)(5) provides some guidance

for storage tanks, but this guidance needs to be expanded to cover other pieces of equipment.

Response: The term recovery device in the proposed rule had the same meaning as in the

HON, but it should have been used only in conjunction with the wastewater provisions. The

MACT floor for process vents is based on the concept that certain condensers are part of the

process (i.e., process condensers) and any other add-on devices are considered to be control

devices; the concept of recovery devices as in the HON does not apply to process vents. For the

final rule, the term recovery device has been revised to include only devices used with water

streams, and to specify that equipment based on gravity separation may be a recovery device only

if all of the inlet streams are two-phase liquid streams. The material recovered in a recovery

device may be used in any process, including non-PAI processes.

3.5 EXEMPTIONS FROM THE RULE

Status at proposal: The proposed rule exempted research and development facilities,

emission points subject to the HON, emission points subject to other MACT standards, a variety

of water discharges, and equipment (i.e., flanges, valves, etc.) in organic HAP service for less

than 300 hr/yr.

Comment 1: Two commenters requested additional exemptions in § 63.1360(d) for

emission streams with certain characteristics. Commenter IV-D-27 suggested the following

should be excluded from the rule: processes where the sum of uncontrolled organic HAP

emissions is <10,000 lb/yr; process vents with concentrations <50 ppmv total organic HAP

concentration or <0.005 standard cubic meters per minute (scmm) flow; and storage tanks with

uncontrolled organic HAP emissions <500 lb/yr. Commenter IV-G-03 requested an overall
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exemption for PAI processes where the total organic HAP emissions are less than 500 lb/yr. 

Commenter IV-G-03 stated that the justification for the exemption is that it meets the intent of

the CAA in that (1) it is protective of human health and the environment, and (2) all PAI

processes achieve a level of control already being achieved by the better controlled and lower

emitting processes. The commenter believes that this overall exemption would be consistent

with the intent of allowing exemptions for individual types of emission points associated with

production of a given product, and the sum of these individual exemptions could conceivably

even exceed the suggested overall cutoff of 500 lb/yr. The commenter also believes an overall

exemption would give potentially affected facilities flexibility to reduce emissions in the most

cost effective way.

Response: The EPA decided not to exempt processes and storage tanks based on

emission stream characteristics. However, based on similar comments regarding the MACT

floor, the applicability cutoffs for storage vessels were revised for the final rule; see section 8.2

for a discussion of the changes. In addition, the definition of process vent was revised to exclude

streams that are undiluted, uncontrolled, and contain less than 20 ppmv of HAP; see the

responses to comment 8 in section 5.2 and comment 1 in section 7.2 for additional information.

An overall cutoff was not included in the proposed rule, and also is not included in the

final rule because it is either inconsistent with the MACT floor or would require a restructuring

of the MACT floor with no clear benefit. Moreover, EPA believes the emissions averaging and

pollution prevention provisions in the rule provide comparable flexibility. It is not clear whether

the commenter wants the exemption to replace the cutoffs for individual types of emission points

(i.e., “individual cutoffs”) or to be in addition to them. If the overall cutoff were to be in addition

to the individual cutoffs it would be inconsistent with the MACT floor because a facility would

only take advantage of it if it were less stringent than the sum of the individual cutoffs, which are

based on the floor. An overall cutoff could not simply replace the individual cutoffs because the

MACT floor consists of individual cutoffs plus control efficiencies for emission points that

exceed the cutoff. Thus, the entire MACT floor would have to be reevaluated to determine an

overall control efficiency to go with it.
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However, the EPA agrees with the commenter that flexibility in compliance is important. 

This is the reason emissions averaging and pollution prevention provisions were included in the

proposed rule, and are retained in the final rule. The emissions averaging provisions allow an

owner or operator to determine the total required emission reduction for a group of emission

points, excluding equipment leak emissions, and to control these emission points in any way that

achieves the total required reduction. The pollution prevention provisions allow an owner or

operator to take credit for substantial reductions in HAP consumption as an alternative to using

add-on control devices to achieve the specified emission reductions.

Comment 2: Commenter IV-D-28 requested an exemption for equipment that does not

handle process fluids (e.g., heat exchange or refrigeration systems). The commenter noted that

previous MACT standards have distinguished production equipment, which handle process

fluids, and other equipment. The commenter suggested the following language based on

§ 63.160(e) of the HON: “Except as provided in this subpart, lines and equipment not containing

process fluids are not subject to the provisions of this subpart. Utilities and other nonprocess

lines, such as heating and cooling systems which do not combine their materials with those in the

processes they serve, are not considered to be part of a process unit.”

Response: The final rule contains requirements for heat exchange systems, which can 

include equipment that does not handle process fluids. The EPA has required some type of

monitoring of noncontact cooling water because heat exchangers are known to leak in the

industry, and could contribute to significant emissions if left uncorrected. For this reason, the

final rule, as well as many other MACT standards, including the HON, and the pharmaceuticals

NESHAP, contain requirements for monitoring of cooling towers under the heat exchange

systems requirements. Regarding the referenced language from subpart H of part 63, EPA

agrees with the commenter that, unless otherwise stated in any subpart that references subpart H, 

lines and equipment not containing process fluids are not subject to the provisions of subpart H,

as the language in § 63.160(e) states. The language of subpart H, however, was meant to exclude

only components in lines that do not contain process fluids from the Leak Detection and Repair

Provisions of subpart H. The proposed rule, by referencing the provisions of subpart H,

including § 63.160(e), also contained this provision.
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Comment 3: Section 63.1360(d)(2) of the proposed rule states that the provisions of the

PAI rule would not apply to emission points in PAI manufacturing operations that meet the

applicability requirements under subparts F, G, H, and I of the 40 CFR part 63. 

Commenter IV-D-28 supports the concept that one rule takes precedence, but believes there are

two deficiencies with the proposed statement. First, the commenter interprets the statement to

mean that, in order to be exempt from the PAI rule, an emission point would have to be subject

to all four subparts at the same time. However, the commenter contends that few, if any,

emission points would meet this condition. Second, the commenter believes it is not useful to

have an exemption that applies only to specific “emission points” within a process unit because

the PAI rule and the four specified subparts deal with different subsets of HAP. As a result, the

commenter believes it is possible that, within a process unit that is subject to one or more of the

specified subparts, the PAI rule may apply to some emission points that are not, individually,

subject to the other subparts. This would mean that two different regulations would apply within

the same process unit, which the commenter contends would be too complex.

To make the exemption achievable and useful, the commenter suggested two changes. 

First, revise § 63.1360(d)(2) to state that emission points in PAI manufacturing operations that

meet the requirements under subparts F, G, and H are not subject to any provisions of the PAI

rule, and emission points that meet the applicability requirements under subparts H and I are not

subject the the requirements in the PAI rule that are related to equipment leaks. Second, add

language similar in concept to that in § 63.160(c) of the HON that would allow a facility to elect

to comply with either another applicable MACT standard (e.g., the HON) or the PAI rule for all

relevant emission points associated with a process unit.

Response: The EPA agrees with the commenter that clarification of the proposed

provision is needed. The EPA did not mean that all four subparts must be applicable

simultaneously for the exemption to be allowed. Further, EPA agrees with the commenter that

all of the emission points in a given process unit should be part of only one source category for

the purposes of applying MACT standards. Therefore, this provision was revised in the final rule

to specify that emission points within a process unit that is subject to subpart F are not subject to

the final rule. References to subparts G and H were deleted because these subparts are cross-
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referenced from subpart F. The proposed exemption for emission points subject to subpart I was

replaced with a provision that allows the owner or operator the option of continuing to comply

with the provisions of subpart I or switching to compliance with the equipment leak provisions in

the final rule (see section 3.8 for more information). These changes are consistent with the

commenter’s first suggestion.

Although some of the compounds subject to the HON are registered as PAI’s, and others

are intermediates in the production of PAI’s, EPA believes the HON should take precedence for

any process that is subject to the HON because such a process is likely to be used predominantly

to produce chemicals in bulk for various uses. Even if the production at a particular facility is

captively used only to produce PAI’s, the HON should take precedence because the process is the

same as that at other facilities that are producing the same chemical for other uses. Therefore,

EPA disagrees with the commenter’s suggestion that a facility be allowed to elect whether to

comply with the HON or the PAI final rule. Overlap with other MACT standards may occur for

some intermediates and nondedicated equipment; the applicability in these situations is discussed

in sections 3.2 and 3.3 of this document.

Comment 4: Section 63.1360(d)(3) of the proposed rule would exempt emission points

in PAI manufacturing operations that meet the applicability criteria under any other existing

MACT standard. Commenter IV-G-01 suggested expanding this exemption to allow a facility to

comply with a more stringent rule in lieu of the PAI rule. For example, the commenter described

a situation in which nondedicated equipment may be used to manufacture pharmaceuticals part of

the year and a PAI for the remainder of the year. Under the proposed rules for the PAI and

pharmaceuticals source categories, the equipment would be subject to the PAI rule when making

a PAI and to the pharmaceuticals rule when making pharmaceutical products. The commenter

believes complying with two standards for the same equipment train would be confusing. As an

alternative to broadening the exemption, the commenter suggested that the rule apply only when

50 percent or more of the annual production from the equipment is a PAI (see comment No. 1 in

section 3.2 of this document).

Response: The EPA decided to delete this provision because: (1) it is redundant with the

provision described in comment 3 above for processes subject to the HON; (2) other than the
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HON, there are no existing MACT standards that would apply to PAI production; (3) inorganic

compounds that may be registered as PAI’s (e.g., sodium dichromate, chromic acid, hydrogen

chloride [HCl], chlorine [Cl2], hydrogen cyanide [HCN]) are part of source categories that have

been deleted or for which standards have not yet been promulgated, and production of inorganic

compounds has been deleted from the PAI source category); and (4) changes to the applicability

of intermediates in the final rule mean it would be unnecessary for production of intermediates

(see section 3.3). The commenter’s concern about nondedicated equipment being subject to

multiple rules is addressed in the response to comment 1 in section 3.2.

Comment 5: Commenter IV-D-28 suggested editorial clarifications to the language used

in §§ 63.1360(d)(2) and (3). Specifically, the commenter suggested using the phrase “within an

affected source subject to” instead of the phrases “that meet the applicability requirements” and

“that meet the applicability criteria.”

Response: In an effort to improve clarity, the final rule uses language similar to that

suggested by the commenter.

3.6 NEW AFFECTED SOURCE

Status at proposal: Section 63.1360(g)(2) of the proposed rule states that an addition of

PAI manufacturing operations at an existing plant site would be subject to the requirements for a

new source if the addition has the potential to emit 10 tons/yr or more of any HAP or 25 tons/yr

or more of any combination of HAP, unless the Administrator establishes a lesser quantity at a

plant that currently is an affected source. New source requirements also would apply to a new

plant site on which construction started after November 10, 1997 or a reconstructed source for

which reconstruction started after November 10, 1997.

Comment 1: Commenter IV-G-03 suggested that § 63.1360(g)(2) be reworded by

inclusion of the phrase “by regulation” after the word “Administrator” so that it does not

arbitrarily extend the Administrator’s decisions of establishing lesser quantities without specific

guidance or regulations.
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Response: The phrase “unless the Administrator establishes a lesser quantity” is

redundant with section 112(a)(1) of the Act. Because of this redundancy it is not included in the

final rule.

Comment 2: Commenters IV-D-21 and IV-D-29 requested confirmation of their

interpretation of § 63.1360(g)(2) to mean that a source with minor actual emissions but major

potential to emit could elect to accept a Federally enforceable “synthetic minor” operating permit

with an emission limit below the 10 and 25 tons/yr cutoffs, and thereby avoid the new source

requirements for process vents, storage tanks, and wastewater. Another commenter (IV-D-28)

supports the approach whereby an addition is subject to new source standards only if it meets the

10 or 25 tons/yr emission level by itself.

Response: The new affected source provisions have been revised for the final rule. As

noted in the responses to comment 1 in section 3.2 and comment 1 in this section, the term “PAI

manufacturing operations” and the phrase “unless the Administrator establishes a lesser quantity”

are not used in the final rule. The EPA also is concerned that the term “addition” may be

ambiguous. The intent was that the requirements apply only to additions consisting of 

equipment dedicated to the production of a single PAI. Therefore, the final rule specifies that

new source requirements apply to an affected source for which construction or reconstruction

commenced after November 10, 1997, or to any single PAI process unit that meets the following

conditions: (1) it is not part of a process unit group, (2) construction commenced after

November 10, 1997, and (3) it has the potential to emit 10 tons/yr of any one HAP or 25 tons/yr

of combined HAP. Under this definition, if an owner or operator elects to accept Federally

enforceable conditions that limit the potential to emit for a single PAI process unit that is added

to an existing facility to levels below these thresholds, the PAI process unit would be subject to

existing source standards, not new source standards.

3.7 STARTUP, SHUTDOWN, AND MALFUNCTION

Status at proposal: For batch processes, § 63.1360(e) of the proposed rule would require

an owner or operator to comply with the provisions in the rule during periods of startup and

shutdown, and periods of malfunction would be regulated according to § 63.6 of the General

Provisions. For continuous processes, § 63.1360(e) of the proposed rule specifies that only
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§ 63.6 of the General Provisions would apply during periods of startup, shutdown, and

malfunction.

Comment: Three commenters addressed the startup, shutdown, and malfunction

provisions in § 63.1360(e) of the proposed rule. Commenter IV-D-28 agrees that routine startups

and shutdowns between batches should be covered by the rule, but stated that it should not apply

during other startups and shutdowns because normal emission control techniques may be

inappropriate or ineffective during those times. According to the commenter, some of the other

situations include (1) initial startup of a process unit, (2) startup after a malfunction or an

extended period of nonoperation, and (3) shutdowns due to a malfunction. The commenter

explained that during initial startup, control devices and monitoring systems need to undergo

“shakedown” and debugging, and may need time to reach their full efficiency. After an extended

downtime, process equipment also will need time to get back to normal operating conditions, and

control devices will need to reach operating temperatures or equilibrium. Although the

commenter understands that the proposed rule would not apply during malfunctions, the

requirements during a shutdown associated with the malfunction were not clear.

Commenter IV-D-28 also stated that the final PAI MACT standards should not

incorporate § 63.6(e) of the General Provisions for four reasons. First, the requirement in

§ 63.6(e)(3)(i)(A) to minimize emissions “at least to the levels required by all relevant standards”

is ambiguous. Second, the General Provisions do not address shutdowns of compliance

equipment such as control devices. Third, the General Provisions do not address startups,

shutdowns, and malfunctions that affect only a portion of the process. Fourth, the General

Provisions do not say how to deal with periods of nonoperation. To address these concerns, the

commenter suggested revising §§ 63.1360(e)(1) and (2) to refer to a new § 63.1360(e)(3) in the

rule instead of § 63.6 of the General Provisions. For the new § 63.1360(e)(3), the commenter

recommended using language similar to that in the HON. The commenter also noted that the

discussion of § 63.6 in Table 1 (the General Provisions applicability table) would need to change

as in the HON.

Commenter IV-D-29 recommended that EPA consider revising § 63.1360(e)(1) of the

proposed rule to allow batch processes with air pollution control equipment to comply with the
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startup, shutdown, and malfunction requirements in 40 CFR 63.6(e). The commenter explained

that operating practices for controls used with batch processes are the same as those for controls

used with continuous processes; for both types of processes, operators verify that all control

equipment is on-line and functioning properly to minimize emissions at all times (consistent with

§ 63.6(e)(1)(i) of the General Provisions). Furthermore, the commenter stated that maintenance

and corrective actions after a malfunction of a control device are the same for both batch and

continuous processes. Therefore, the commenter recommended that EPA consider revising the

rule to include the following language: “For batch processes with air pollution control

equipment, startup, shutdown, and malfunction shall be regulated according to section 63.6 of

subpart A of this part. For batch processes without air pollution control equipment, the

provisions of this subpart shall apply during startup and shutdown, and periods of malfunction

shall be regulated according to § 63.6 of subpart A of this part.”

Response: The EPA has reconsidered the applicability of the rule during periods of

startup and shutdown and determined that the requirements of the rule should not be applied

under certain situations for batch processes as well as for continuous processes. For batch

processes, these situations include initial startups of new or reconstructed processes, and

shutdowns that are not part of intended operation (e.g., for maintenance, replacement of

equipment, or other repair as a result of a malfunction). These are times when the operators may

be unfamiliar with the equipment operation or it may not be possible to follow standard operating

procedures. However, setting the equipment in operation after maintenance (including

maintenance to correct a malfunction), after switching to a product that has been produced in the

past, or for each batch during a campaign are all routine, normal operating conditions that should

result in the same emissions profile. Similarly, the cessation of operation at the end of a

campaign, between batches, or for planned, preventive maintenance are all normal operations

with the same emissions profile. Conversely, for continuous processes, startup and shutdown for

any reason results in operation under conditions different from the normal steady-state operation. 

To account for these differences between batch and continuous processes, the final rule provides

definitions for startup and shutdown that differ from the definitions in the General Provisions. 

Specifically, the following definitions have been added to the rule:
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Startup means the setting in operation of a continuous PAI process unit for any purpose,

the first time a new or reconstructed batch PAI process unit begins production, or, for new

equipment added to any PAI process unit, including equipment used to comply with this subpart,

the first time the equipment is put into operation. For batch process units, startup does not apply

to the first time the equipment is put into operation at the start of a campaign to produce a

product that has been produced in the past, after a shutdown, or when the equipment is put into

operation as part of a batch within a campaign. As used in § 63.1363, startup means the setting

in operation of a piece of equipment or a control device that is subject to this subpart.

Shutdown means the cessation of operation of a continuous PAI process unit or any

equipment within the PAI process unit, including equipment required or used to comply with this

subpart, for any purpose. Shutdown also means the cessation of a batch PAI process unit, any

equipment within the PAI process unit, or any individual piece of equipment required or used to

comply with this part or for emptying and degassing storage vesselsas the result of a

malfunction. Shutdown does not apply to cessation of a batch PAI process unit at the end of a

campaign, for routine maintenance, for rinsing or washing of equipment between batches, or

other routine operations.

The EPA has also clarified in the final rule that the provisions can apply to processing

equipment, as well as control, monitoring, and recordkeeping equipment. Additionally, in

response to the commenter’s concerns regarding ambiguity of the general provisions, EPA has

replaced the reference to the general provisions with language from the HON that specifically

clarifies applicability of provisions during startup, shutdown, and malfunction events.

3.8 OVERLAP WITH OTHER REGULATIONS

Comment: Three commenters stated that, in addition to the exemptions in § 63.1360(d)

of the proposed rule, the rule must also address overlaps with other regulations. 

Commenter IV-D-28 identified overlaps with NSPS under part 60, NESHAP under part 61, and

RCRA equipment leaks requirements that are not addressed. Commenters IV-D-21 and IV-D-29

went a step further and identified specific NSPS and NESHAP with overlapping provisions for

Group 1 PAI vents (i.e., NSPS subparts Kb, III, NNN, and RRR; and NESHAP subparts BB, FF,

and G). All three commenters suggested revising the rule to include language similar to that in
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§ 63.110 of the HON for provisions dealing with process vents, storage tanks, and wastewater. 

Commenter IV-D-28 also suggested borrowing language from §§ 63.160(b) through (d) to

address overlapping provisions that deal with equipment leaks.

Response: The EPA agrees with the commenters that the rule must address overlap with

other regulations. The final rule includes language similar to that in § 63.110 of the HON for

overlap with NSPS requirements for storage vessels in subpart Kb of 40 CFR part 60 and RCRA

requirements in 40 CFR parts 260 through 272. The EPA also added a provision specifying that

an owner or operator subject to both this rule and the equipment leak requirements in subpart I of

40 CFR part 63 may elect to comply with the requirements of either rule.

The requirements in NSPS subparts III, NNN, and RRR apply to individual vents,

whereas the process vent standards in the final rule apply to the sum of all process vents within a

process. As a result, a facility generally must comply with both the final rule and any applicable

NSPS. One exception is provided in the final rule. If an owner or operator elects to reduce

emissions from a process vent by 98 percent (or implement an equivalent control option), then

the owner or operator is required to comply only with the provisions of the final rule.

The final rule does not address overlap with NESHAP in 40 CFR part 61. Subparts BB

and FF regulate emissions from benzene production, which, because it is subject to the HON, is

not subject to the PAI rule. Subpart G is reserved and also is not covered in § 63.110 of the

HON.

3.9 STORAGE TANK ASSIGNMENT

Status at proposal: Section 63.1360(f) of the proposed rule specifies procedures to

determine if storage tanks, including storage tanks in a tank farm, are part of the affected source. 

Under the proposed rule, a storage tank would be part of the affected source if the majority of its

throughput is associated with PAI processes. If the use varies from year to year, the

determination would be based on the utilization that occurred during the year preceding

publication of the proposed rule (i.e., November 10, 1997). A storage tank in a tank farm would

not be part of the affected source if all of its throughput went through intervening tanks between

it and the applicable processes. The proposed rule also specifies that if there is a significant
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change in the use of the storage tank that the owner or operator would be required to reevaluate

the applicability of the rule for that tank.

Comment: Commenter IV-D-28 addressed two aspects of the storage tank applicability

determinations. First, the commenter stated that for storage tanks in a tank farm, the provisions

in § 63.1360(f)(3)(ii) of the proposed rule do not indicate whether material from or to intervening

tanks should be excluded or included in the “predominant use” calculation. The commenter

recommended that the language from § 63.100(g)(3) of the HON be used without modification

because those provisions are clear and complete; it would also make the PAI rule more consistent

with the HON. Second, the commenter stated that a facility should not be required to reevaluate

the applicability every time the predominant use may have changed. The commenter believes

that frequently changing storage tank assignments would make the compliance program difficult

to administer, and that the reevaluation is unwarranted because changes in usage between process

units are accounted for in the initial assignment determination.

Response: The EPA agrees with the commenter that the rule must indicate how material

from or to intervening tanks is to be used in the predominant use calculation. Language from

§ 63.100(g)(3) of the HON was not copied verbatim into the proposed rule because a storage tank

was only assigned to the PAI manufacturing operations in general; it was not necessary to assign

it to a specific PAI process unit. However, because the concept of process units was added to the

final rule for other reasons, the language from § 63.100(g)(3) was also added to the final rule. 

The final rule retains the requirement to reevaluate the applicability assignment if the storage

vessel begins receiving material from (or sending material to) another process unit because these

are significant changes that are not accounted for in the initial evaluation. For example, if a tank

is no longer associated with a given process, it should no longer be assigned to the process unit

for that process.
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4.0 COMPLIANCE DATES

4.1 EXISTING SOURCES

Comment: Four commenters addressed the issue of the compliance date for existing

sources. Commenter IV-D-15 stated that EPA should delay implementation of the rule to allow

facilities to comply with the HON and then reassess their potential to emit. 

Commenters IV-D-16 and IV-D-28 supported the proposed compliance date of 3 years after

promulgation. Commenter IV-D-17 urged EPA to seek expeditious promulgation,

implementation, and enforcement of the proposed limits; this commenter believes a compliance

date sooner than the statutory maximum of 3 years after promulgation might be appropriate and

is certainly achievable.

Response: The compliance date cannot be more than 3 years after promulgation because,

as one commenter noted, 3 years is the maximum time allowed under the Act. However,

section 112(i)(3)(B) of the Act and § 63.6(i) of the General Provisions allow an owner or

operator to request an extension of compliance of up to 1 additional year if the additional period

is necessary for the installation of controls. To make this provision more visible, it also has been

stated in the final rule. The EPA does not believe commenter IV-D-17 presented a compelling

argument for a compliance date sooner than 3 years after promulgation. Thus, EPA continues to

believe that 3 years is a reasonable time period, and appreciates the support of two of the

commenters in this regard.

4.2 NEW SOURCES
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Comment 1: Commenter IV-D-28 believes the proposed provision that would require

new sources to be in compliance upon startup should be revised to require compliance by initial

startup or the promulgation date of the rule, whichever is later.

Response: A provision requiring that new sources be in compliance by initial startup or

the promulgation date, whichever is later, is consistent with other MACT standards and has been

added to the final rule.

Comment 2: Commenters IV-D-21 and IV-D-29 suggested adding a provision that would

extend the compliance date for new sources that commence construction after proposal but

before promulgation if the final standard is different from the proposed standard and the owner or

operator complies with the standard as proposed during the 3-year period immediately after the

effective date.

Response: The language suggested by the commenter is similar to the provisions in

sections 112(i)(2) of the Act and § 63.6(b)(3) of the General Provisions (except these provisions

refer to final standards that are “more stringent,” as opposed to merely “different,” than the

proposed standards). The EPA assumes the commenters are relying on these authorities for their

requests. Because the final rule is not more stringent than the proposed standards, there is no

need to include this provision in the final rule.

Comment 3: Commenters IV-D-21 and IV-D-29 believe EPA should either allow new

sources a period of up to 6 months to complete any required testing after startup, or change the

definition of startup to stipulate that startup is not complete until all required performance testing

is complete and that this testing must be completed no later than 6 months after steady state

production for continuous processes or until 6 months after a successful batch production run has

been completed.

Response: The EPA does not believe that the compliance date needs to be changed to

accommodate required emissions testing. Under the proposed rule, an owner or operator would

be required to submit the Notification of Compliance Status report no later than 150 days after

the compliance date (i.e., startup for a new source). This requirement is consistent with other

MACT standards (e.g., the HON, Polymers and Resins [P&R] I, and P&R IV), and it is nearly

the requested 6 months after the compliance date. Furthermore, much of the work (e.g., the
4-3

emissions profile) may be completed before the compliance date. The amount of time needed to

reach steady state production or to complete a successful batch production run should not be

greater in this industry than in other chemical production industries. Therefore, the final rule

retains the provision to submit the Notification of Compliance Status report no later than

150 days after the compliance date.
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5.0 DEFINITIONS

5.1 NEW TERMS DEFINED IN THE FINAL RULE

Comment 1: Commenter IV-D-28 requested that EPA provide a definition for Flame

Ionization Detector (FID).

Response: In the final rule, FID is defined to mean “a device in which the measured

change in conductivity of a standard flame (usually hydrogen) due to the insertion of another gas

or vapor is used to detect the gas or vapor.”

Comment 2: Commenters IV-D-28 and IV-G-03 requested that EPA provide a definition

for TOC.

Response: In the final rule, TOC is defined to mean “those compounds measured

according to the procedures of Method 18 or Method 25A of 40 CFR part 60, appendix A.”

Comment 3: Commenter IV-D-28 requested that EPA add definitions for startup and

shutdown consistent with the HON.

Response: Definitions for these terms in the final rule are presented in the response to

comments on startup, shutdown, and malfunctions in section 3.7 of this document.

Comment 4: A number of commenters (IV-D-14, IV-D-21, IV-D-28, IV-D-29, and

IV-G-03) requested that the rule define both process wastewater and maintenance wastewater.

Response: The final rule includes definitions for both of these terms that are consistent

with the definitions in the HON. The terms were added because the requirements in the final rule

for maintenance wastewater differ from the requirements for process wastewater. See

section 10.2 for a discussion of the changes to the maintenance wastewater provisions.
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Comment 5: Commenters IV-D-14, IV-D16, and IV-D-28 requested that the final

regulation include a definition of “bag dumps.” 

Response: The final rule defines bag dumps to be equipment into which bags or other

containers containing a powdered, granular, or other solid feedstock material are emptied. To be

complete, the final rule also defines product dryer as equipment that is used to remove moisture

or other liquid from granular, powdered, or other solid PAI or integral intermediate products

prior to storage, formulation, shipment, or other uses.

Comment 6: Commenter IV-D-15 stated that the rule needs to include a definition for

“storage” to clarify which intermediate process are integral or non-integral.

Response: The definition of “storage” as it relates to intermediates is described in the

response to comments in section 3.3 of this document.

Comment 7: Commenter IV-D-28 requested that EPA define “organic HAP” by listing

covered compounds because compounds like phosgene and cyanide compounds do not have

universal interpretations.

Response: The final rule defines organic HAP as “those HAP listed in section 112(b) of

the Act that are measured according to the procedures of Method 18 or Method 25A, 40 CFR

part 60, appendix A, and exist in the vapor phase at ambient conditions.”

5.2 REVISED DEFINITIONS THAT DIFFER FROM COMMENTERS SUGGESTIONS

Comment 1: Commenter IV-D-28 requested that EPA change the definition of “Group 1

storage tank” to match the HON because control of 240 lb/yr or 1 lb/yr is unlikely to be cost

effective, and consistency with the HON reduces regulatory burden.

Response: The responses to comments in sections 8.1 and 8.2 of this document describe

changes to the MACT floor and standard for storage vessels. As a result of these changes to the

floor, the definition of “Group 1 storage vessel” for the final rule has been changed to be

consistent with the HON, except that the vapor pressure cutoffs differ. For existing sources, the

vapor pressure cutoff is 3.45 kPa for storage vessels with a capacity greater than or equal to 75

cubic meters (m ). For new sources, the cutoff is 16.5 kPa for storage vessels with a capacity 3
5-3

greater than or equal to 38 m and less than 75 m , and 3.45 kPa for storage vessels with a 3 3

capacity greater than or equal to 75 m .

3

Comment 2: Commenters IV-D-21 and IV-D-29 stated that the final rule should include

a definition of impurity because one of the exemptions is for “vessels and equipment storing

and/or handling material that contain no organic HAP and/or organic HAP as an impurity only.” 

The commenters suggested the following wording: “A substance that is produced coincidentally

with the primary product, or is contained in the final product as a contaminant serving no useful

purpose, or is present in a raw material. An impurity does not serve a useful purpose in the

production or use of the primary product and is not isolated.”

Response: The EPA agrees with the commenter that a definition of the term “impurity” is

needed to clarify the use of this term in the definition of storage vessel. The final rule defines

impurity as “a substance that is produced coincidentally with the product(s), or is present in a raw

material. An impurity does not serve a useful purpose in the production or use of the product(s)

and is not isolated.” The exemption cited by the commenter also has been revised in the final

rule by deleting the words “and equipment” and the words “and/or handling.” Removing these

words clarifies the original intent of the statement, which was to exempt certain storage vessels.

Comment 3: Commenter IV-G-03 stated that the definition of “wastewater” needs

clarification with regard to the second criterion, which is that it must be water that “is discarded

from PAI manufacturing operations at a major source.” The commenter stated that this implies

that the “source” in question that must meet the definition of “major” is the vessel, tank, process

equipment.

Response: In the final rule this criterion has been changed to be water that “is discarded

from a PAI process unit that is at an affected source.” The term “PAI manufacturing operations”

was replaced with the term “PAI process unit” to clarify that the wastewater is discarded from

process equipment or storage vessels and because, as discussed in the responses to comment 7 in

this section and to comments 1 and 2 in section 3.3, the term “PAI manufacturing operations” has

been deleted from the final rule. The phrase “at a major source” was replaced with the phrase

“that is at an affected source” to clarify that the discharge is only classified as wastewater if it is

from a PAI process unit that processes, uses, or produces HAP and is located at a major source. 
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The definition of wastewater was also changed in other ways as part of the changes in the

provisions for maintenance wastewater; these changes are described in section 10.2 of this

document.

Comment 4: The proposed rule states that to be a process condenser, the primary

purpose of the condenser must be to recover material as an integral part of a unit operation, and

the condenser must support a vapor to liquid phase change for periods of source equipment

operation that are above the boiling or bubble point of substances. Several examples of process

condensers were also provided. Commenter IV-G-01 recommended changing the proposed

definition because the requirement that source operation be above the boiling or bubble point

temperature means that a given condenser will sometimes be a process condenser, and sometimes

it will be an air pollution control device. The commenter believes this will cause confusion for

the facility, and tracking the changes from one classification to the other will be burdensome. 

Therefore, the commenter recommended that the definition be changed to mean “a condenser

whose primary purpose is to recover material as an integral part of the unit operation, or is

essential to effectively run the process.” Furthermore, the commenter believes the facility, which

is more familiar with the process than anyone else, is in the best position to determine whether it

should be considered a process condenser or an air pollution control device.

Commenter IV-D-28 requested that the definition of “process condenser” be clarified

because the term “integral” is not defined, the term “unit operation” is used incorrectly (see 

comment 7 in section 5.4), it is not clear what the term “support” means, it is not clear what the

difference is between the boiling and bubble point, the term “substance” should be limited to

HAP, and the examples are circular because they use the term “process condenser.”

Response: The EPA agrees with the commenter that a given condenser may be classified

as a process condenser at some times and as an air pollution control device at other times. 

However, EPA believes the conditions for both types of situations are clearly defined in the final

rule and that this approach is preferable over potentially arbitrary classifications based on its

typical use over all uses. Because one of the formats of the process vent standard requires that a

reduction from uncontrolled emissions be applied across all vents within a process, EPA is

concerned about the opportunity for crediting reductions achieved by condensing boiling streams
5-5

on other sources in the process (i.e., overestimating the control by calling the condenser an air

pollution control device for all inlet streams).

Although the basic concept of the definition is unchanged in the final rule, a number of

editorial changes were made to clarify the meaning. For the final rule, process condenser is

defined to mean “a condenser whose primary purpose is to recover material and is an integral

part of a unit operation. The condenser also must cause a vapor-to-liquid phase change for

periods during which the temperature of liquid in the process equipment is at or above its boiling

or bubble point. Examples of process condensers include distillation condensers, reflux

condensers, and condensers used in stripping or flashing operations. In a series of condensers, all

condensers up to and including the first condenser with an exit gas temperature below the boiling

or bubble point of the liquid are considered to be process condensers. All condensers in line

prior to the vacuum source are included in this definition.” The definition retains the term

“bubble point” because a liquid mixture does not boil at only a single temperature. For a mixture

of two or more components, the bubble point is the temperature at which the first bubbles of

vapor form in the liquid. In the examples, the process condenser is considered “an integral part

of the unit operation” because process could not be operated without the condenser.

Comment 5: Commenter IV-G-01 recommended that the definition of “pesticide active

ingredient manufacturing operations” should not include waste management units. The

commenter stated that in other standards the waste management units are not part of the

applicable process units and thus are not subject to the standard but are instead used to comply

with the standard. The commenter also concluded that the proposed definition could be

interpreted to require compliance with the new source standards at an existing waste management

unit simply because a new and major PAI manufacturing operation has been built that will

contribute wastewater to the unit.

Response: As discussed in the response to comments in section 3.2 of this document, the

term “PAI manufacturing operations” has been deleted from the final rule. The definition of the

affected source has also been revised, and a new term, “PAI process unit,” has been added. The

PAI process unit is comparable to the chemical manufacturing process unit (CMPU) in the HON,

and it does not include the waste management units. However, waste management units are part
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of the affected source, as in the HON and other standards. Finally, the commenter’s conclusion

regarding the application of new source requirements is correct. If a new PAI process unit that

meets the requirements for new source applicability (see section 3.6 of this document for a

discussion of changes in these requirements), then the waste management units associated with

that new PAI process unit would have to meet the requirements for new sources. The practical

impact of this requirement, however, is expected to be minimal because the requirements for new

sources and existing sources are identical except when the HAP load to the waste management

unit exceeds 2,100 Mg/yr. Based on survey data from the industry, no single existing PAI

process unit discharges wastewater with such a high load (and only one facility discharges

wastewater containing that much HAP).

Comment 6: Commenter IV-D-09 stated that the definition of “pesticide active

ingredient” must be revised to be consistent with the basis and purpose document. The

commenter asserted that PAI’s derived from naturally occurring substances are not “synthetically

manufactured” or “produced in a chemical reaction” and should not be regulated by the proposed

NESHAP. 

Response: Processes that derive PAI’s from naturally occurring substances most likely

will be subject to the rule if they are extracted with HAP solvents. Such extraction is comparable

to extraction used in production of synthetic organic PAI’s. Thus, the production of PAI’s

derived from naturally occurring substances has not been deleted from the definition of PAI in

the final rule. Only sources that use a HAP are regulated; therefore, many producers of PAI’s

from naturally occurring compounds are not regulated. However, as noted in the response to

comments in sections 3.1 and 3.2 of this document, production of inorganic compounds has been

deleted from the affected source, and production of compounds that are primarily used for nonpesticidal purposes is not subject to the final rule.

Comment 7: Commenter IV-D-28 believes EPA should replace the term “process” with

the term “process unit,” and then add a new term called “PAI process unit.” The commenter

finds the proposed definition of “process” unclear for several reasons. First, it forces a subtle,

non-obvious departure from common usage for the term; by defining it as equipment that is used

to produce PAI’s, it means equipment used to produce other products cannot be called a process. 
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Second, it does not require a process to consist of more than one unit operation; the commenter

noted that the HON was amended to clarify that a CMPU consists of two or more unit operations

(the commenter also objected to changing the definition of unit operation from the definition in

the HON; see comment 7 in section 5.4 of this chapter). Third, inconsistencies among

regulations are likely to lead to problems in establishing and implementing compliance programs

at facilities with processes subject to different regulations. To resolve some of these concerns,

the commenter believes a generic term, “process unit,” should be added with a definition that

encompasses all of the different types of process units in other MACT standards. The

commenter also would add the new term “PAI process unit” to define a specific type of process

unit that is subject to the PAI MACT standard. The commenter supports the exclusion of

formulation from the definition of “process” (or “PAI process unit”).

Response: Many of the changes suggested by the commenter have been incorporated in

the definitions in the final rule. The term “process” has been retained, but the definition has been

changed to refer to the production of any product, not just PAI’s. The generic term “process

unit” has been added to parallel the term CMPU in the HON, and the term “PAI process unit” has

been added and defined as a process unit that is used to produce a PAI or integral intermediate. 

The definition also describes other features of a PAI process unit based on language in the

proposed definition of “process,” but it does not specify that a PAI process unit must consist of at

least two unit operations. See the response to comments in section 3.2 of this document for more

information about the changes in these definitions as they relate to the definition of the affected

source. 

Comment 8: In the proposed rule, a process vent was defined as “a vent from a unit

operation through which a HAP-containing gas stream is, or has the potential to be, released to

the atmosphere.” Examples of process vents and emission points that would not be process vents

were also included in the definition. The proposed rule defined a product dryer vent as “a vent

from an atmospheric dryer through which a gas stream containing gaseous organic HAP,

particulate matter HAP, or both is, or has the potential to be, released to the atmosphere. 

Commenter IV-D-28 requested that EPA modify these definitions to include a de minimis HAP

concentration cutoff (because the proposed definition would apply even to controlled sources),
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specify which HAP are covered (the commenter understands the rule to mean organic HAP and

HCl), exclude streams that are routed to a fuel gas system, and delete the phrase “has the

potential to be.”

In the proposed rule, a Group 1 process vent was defined as a “process vent from a

process at an existing or new affected source for which the uncontrolled emissions from the sum

of all process vents are greater than or equal to 150 kilograms per year (kg/yr) (330 lb/yr).” 

Three commenters (IV-D-21, IV-D-28, and IV-D-29) requested that EPA change this definition

to match the HON. Commenters IV-D-21 and IV-D-29 suggested the following language:

“. . . Group 1 process vent means any process vent from a continuous process at an existing or

new affected source for which the flow is greater than or equal to 0.005 cubic feet per minute

(scfm), the total organic HAP concentration is great than or equal to 50 ppmv, and the total

resource effectiveness index value, calculated according to § 63.115 of subpart G, is less than or

equal to 1.0.” The commenters suggested the following for batch process vents: “Group 1

process vent means any process vent at an existing or new affected source with uncontrolled

emissions greater than 330 lb/yr.”

Response: The definition of “process vent” in the final rule incorporates several of the

suggested changes. Specifically, the definition excludes streams with low HAP concentrations

(20 ppmv was selected instead of the suggested 50 ppmv), the phrase “has the potential to be”

has been deleted, and the type of HAP has been identified. Although concentration data are not

available from the surveyed plant, streams with concentrations below 20 ppmv are likely to be

uncontrolled because that level is considered to be the practical limit of control. Furthermore,

such streams are likely to have low annual emissions, and thus have little impact on the

applicability determination for a process. The exemption for fuel gas systems has not been

included for reasons discussed in the response to comments in section 6.3 of this document. In

the final rule, a process vent is defined as:

a point of emission from processing equipment to the atmosphere or a control device. 

The vent may be the release point for an emission stream associated with an individual unit

operation, or it may be the release point for emission streams from multiple unit operations that

have been manifolded together into a common header. Examples of process vents include, but

are not limited to, vents on condensers used for product recovery, bottom receivers, surge control

vessels, reactors, filters, centrifuges, process tanks, and product dryers. A vent is not considered
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to be a process vent if the undiluted and uncontrolled emission stream that is released through the

vent contains less than 20 ppmv HAP, as determined (1) through process knowledge that no HAP

are present in the emission stream; (2) using an engineering assessment as discussed in

§ 63.1365(b)(2)(ii); (3) from test data collected using Method 1818 of 40 CFR part 60,

appendix A; or (4) from test data collected using any other test method that has been validated

according to the procedures in Method 301 of appendix A of this part. Process vents do not

include vents on storage vessels regulated under § 63.1362(c), vents on wastewater emission

sources regulated under § 63.1362(d), or pieces of equipment regulated under § 63.1363.

The other suggested changes to the definition of Group 1 process vent have not been

included in the final rule because they would be inconsistent with the MACT floor for process

vents. The MACT floor was developed by evaluating all PAI processes in one group, and

considering the emissions from the sum of the process vents within each process. However, as

noted above, EPA did change the definition of “process vent” to exclude emission streams with

HAP concentrations less than 20 ppmv; this change also affects Group 1 process vents.

The definition of a product dryer vent was changed to indicate that it is a process vent. 

Thus, the 20 ppmv cutoff also applies to product dryer vents. However, even if the organic HAP

and HCl/Cl2 concentrations are below 20 ppmv, the product dryer vent is still subject to the

0.01 gr/dscf standard for particulate matter emissions.

Comment 9: Commenter IV-D-28 supports the definitions of recapture device and

recovery device. 

Response: These terms were mistakenly used in several places in the proposed rule;

except for the concept of recovery from water streams, they are not used in the final rule. These

terms are not used in the process vent provisions in the final rule because they conflict with the

terms “process condenser” and “air pollution control device.” An EPA survey of the industry

specified that respondents distinguish between process condensers and air pollution control

devices, and the MACT floor was based on this information. This approach is simpler than the

three-term approach used in the HON, and it draws a clearer distinction between equipment that

is essential to the operation of the process and equipment that is used primarily to control

emissions. There may be incidental recovery of compounds that are collected in some absorbers
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and carbon adsorbers, but the intended purpose of such equipment is likely to be as an air

pollution control device.

The HON specifies that water is not wastewater until after it exits the last recovery

device. Because the final rule, like the proposed rule, continues to cross-reference the

wastewater provisions in the HON, the concept of recovery also is retained in the wastewater

provisions in the final rule.

5.3 REVISED DEFINITIONS CONSISTENT WITH COMMENTERS SUGGESTIONS

Comment 1: A number of commenters (IV-D-16, IV-D-20, IV-D-21, IV-D-28, and

IV-D-29) requested that the definition of “cover” be made consistent with the definition in the

HON by deleting the requirement that covers be sealed.

Response: The requirement that covers be sealed has been deleted from the definition in

the final rule to be consistent with the definitions in previous rules.

Comment 2: Commenters IV-D-21 and IV-D-29 stated that EPA has not explained or

justified the reason why hoses should be considered containers in the PAI industry, but not in the

SOCMI. The commenters recommend that EPA remove hoses from the definition of containers

in this rule.

Response: Hoses have been deleted from the definition of containers in the final rule

because they are not used as containers and were mistakenly included in the proposed rule.

Comment 3: Commenter IV-D-28 stated that EPA should not use the term “isolated

intermediate” because this term has a different meaning under TSCA, which will cause

confusion.

Response: The EPA agrees with the commenter’s concern. The term “isolated

intermediate” has been deleted from the final rule to avoid confusion.

Comment 4: Commenter IV-D-28 requested that the definition of “hard-piping” be

revised to mean pipe as well as tubing, which would be consistent with the HON.

Response: The EPA agrees that the definition should be consistent with the HON. The

definition of “hard-piping” has been changed in the final rule to mean pipe as well as tubing.
5-11

Comment 5: Commenter IV-D-28 stated that the definition of Publicly-Ownted

Treatment Works (POTW) is too wordy and only needs to state “as defined at 40 CFR part

403.3(O)”. The commenter stated that the rest of the existing definition serves no purpose and

can do harm if, for example, one regulation or the other is amended in a nonuniform way.

Response: The EPA agrees that the definitions should be identical and avoid potential

discrepancies that might result from amendments to the Clean Water Act regulations. The final

rule states that POTW is defined in 40 CFR part 403.3(O).

Comment 6: Commenter IV-D-28 stated that contrary to the definition, a “continuous

process” is not “typically steady state;” it typically “approaches” steady state, which is an ideal

condition that does not exist most of the time.

 Response: The commenter is correct; the word “approaches” has been added to the

definition of “continuous process” in the final rule.

Comment 7: Commenters IV-D-21 and IV-D-29 stated that although the basic definition

of point of determination (POD) is a paraphrase of the HON, the NOTE attached to the POD

definition has a reference to TABLE 8 compounds in addition to TABLE 9 compounds. The

commenters stated that TABLE 8 is not mentioned anywhere else in the proposed rule and the

commenters believe this was a transcription error and should be deleted; TABLE 9 is the only list

needed for both new and existing PAI manufacturing operations. Commenter IV-D-28 stated

that the proposed definition of POD is unclear, primarily because it uses the term “process,”

which is also unclear. The commenter stated that the definition of POD should be changed to

match the HON.

Response: For the final rule, the definition of POD has been changed to mean “each

point where a wastewater stream exits the PAI process unit.” This definition is consistent with

the definition in the HON. All references to Table 8 compounds in the proposed rule were

inadvertent and have been deleted from the final rule.

Comment 8: Commenter IV-D-16 requested that nonwastewater “waste” tanks under the

definition of “storage tank” be exempt since this type of tank was not included in the storage tank

database. Commenter IV-D-27 stated that EPA should include the following exclusions to the
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definition of storage tank: tanks regulated under 40 CFR 260-270 RCRA provisions; and other

waste (nonwastewater) tanks. 

Response: For the final rule, the definition of storage vessels states that nonwastewater

waste tanks are not considered to be storage vessels. Tanks regulated under 40 CFR parts

260 through 270 are a subset of all nonwastewater waste tanks.

5.4 DEFINITIONS UNCHANGED SINCE PROPOSAL

Comment 1: Commenter IV-D-28 requested that the definition of “internal floating

roof” should use the term “fixed roof,” not “permanently affixed roof.”

Response: The suggested change would not change the meaning of the definition. To be

consistent with other regulations, the definition has not been changed in the final rule.

Comment 2: Commenter IV-D-28 stated that the definition of liquid-mounted seal must

be incorrect because there should never be any liquid between the wall of the storage tank and the

floating roof.

Response: The definition states that the seal must be “mounted in contact with liquid

between the wall of the storage vessel or waste management unit and the floating roof.” This

means the base of the seal, which is between the wall and the roof, is also in contact with liquid. 

Therefore, the definition of liquid-mounted seal has not been changed for the final rule.

Comment 3: Commenter IV-D-16 requested that the definition of “Group 1 wastewater

stream” be revised to mean either process wastewater meeting the criteria in § 63.132(c) of the

HON or the criteria in the proposed pharmaceuticals regulation, not just the HON criteria. The

commenter recommended this change as a way to exclude streams with low emission potential

from control requirements. In addition, the commenter believes that not having definitions for

“partially soluble HAP” and “soluble HAP” (i.e., terms used in the pharmaceuticals regulation)

could result in confusion and misapplications during implementation by State authorities. 

Therefore, the commenter requested that EPA define these terms by listing the compounds in

each category.

Response: Applying only the criteria from the proposed pharmaceuticals regulation

would result in a different group of streams being subject to treatment requirements. Allowing
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both sets of criteria would result in fewer streams being treated, and less emissions reduction

would be achieved. Because the standard as proposed was determined to be cost effective, the

EPA decided not to change the definition of Group 1 wastewater stream. The EPA also did not

add definitions for partially soluble HAP and soluble HAP because these terms are not used in

the rule.

Comment 4: Three commenters (IV-D-16, IV-D-22, and IV-D-27) stated that EPA needs

to supply a definition for “particulate HAP” or specifically identify which of the HAP listed

under CAA Section 112(b) are particulates covered under the bag dump and product dryer

standard. The commenters suggested that the definition of “particulate HAP” should be as

follows: “any air pollutant listed in or pursuant to section 112(b) of the Act which is a solid

material at ambient conditions and which exists as discrete particles over a wide range of sizes.”

Response: As described in section 11.1 of this document, the standards for bag dumps

and product dryers in the final rule have been changed to be for particulate matter rather than

particulate HAP. Therefore, a definition of particulate HAP is not needed.

Comment 5: Commenter IV-D-28 requested that EPA provide a definition for the term

“planned, routine maintenance.”

Response: The final rule states that in the Notification of Compliance Status report and

each Periodic report, the owner or operator must describe the maintenance that is anticipated for

the storage vessel control device during the next 6 months. The EPA believes that this provision

is clear, and that a definition of planned routine maintenance is not necessary.

Comment 6: Commenter IV-D-28 requested that the definitions of “batch process” and

“continuous process” be deleted because it is the unit operations that comprise a process that are

either batch or continuous, and both types may exist within a process.

Response: The final rule retains definitions for batch and continuous processes because

the terms are used in certain provisions. For example, the pollution prevention provisions

require the owner or operator to calculate HAP and VOC factors every 30 days for continuous

processes and every 10 batches for batch processes. However, to address the situation of a

process that consists of both batch and continuous unit operations, the final rule specifies that
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such a process is considered to be a continuous process for the purposes of the pollution

prevention provisions.

Other instances where the term “batch process” was used in the proposed rule have been

changed to focus on unit operations within the process. For example, the block averaging period

for monitoring in the proposed rule was defined as equal to, at a maximum, the period from the

beginning to the end of a batch process. For the final rule, this provision has been changed to

specify that the block averaging period is equal to the time, at a maximum, from the beginning of

the first batch unit operation to the end of the last batch unit operation in a process.

Similarly, the recordkeeping provisions in the proposed rule would require the owner or

operator to keep a record of the number of batches produced during a year. For the final rule, this

provision was changed to specify that the owner or operator must keep records of the number of

batches for batch processes, the number of operating hours for continuous processes, and both

the number of batches for batch unit operations and the operating hours for the continuous unit

operations within a process that contains both types of unit operations.

Comment 7: Commenter IV-D-28 found the definition of “unit operation” in the

proposed rule to be confusing and requested that EPA change it to match the definition in the

HON. The commenter considers the definition in the HON to be clear because it refers to

equipment, and it specifies that a unit operation makes a single physical or chemical change to a

stream. The proposed rule defined a unit operation as a processing step, and did not refer to

physical or chemical changes in the stream. The commenter also explained that the term

“distillation column” was replaced with the term “distillation unit” in the HON because two

columns may be designed to work together to make a single change to a stream, in which case

both columns, together, are within the same unit operation. In addition, each distillation column

has a reflux condenser, which is part of the “unit.”

Response: A unit operation is an activity, not a piece of equipment. For example, unit

operations include filling, mixing, absorption, reaction, extraction, heating, distillation, washing,

decanting, filtering, and drying. The term “unit operation” is used in the definitions of “batch

emission episode,” “process condenser,” and “process vent” to characterize the type of activity

that causes emissions. It is the activity, not the equipment, that changes the characteristic (or
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possibly multiple characteristics) of the stream and that may result in an emissions episode. 

Furthermore, multiple activities with different emission levels may occur in a given piece of

equipment (e.g., filling followed by pressurization, reaction, and depressurization). Because

compliance demonstrations are based on determination of the emissions from each emissions

episode (which are then summed as appropriate for a given process vent), EPA believes it is

reasonable to link the unit operation with the activity that causes the emission rather than the

equipment from which the emission occurs. The term “distillation column” has been replaced

with “distillation unit.”

Comment 8: Commenter IV-D-28 requested that EPA add a definition of control device

consistent with the HON.

Response: The definition in the HON refers to combustion, recovery, and recapture

devices, and for process vents, recovery devices are not considered to be control devices. As

described above, the final rule considers add-on devices to be either control devices or process

condensers. Otherwise, the definition in the final rule is comparable to the definition in the

HON.
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6.0 STANDARDS-GENERAL

6.1 HEAT EXCHANGER SYSTEMS

Comment: Commenter IV-D-16 stated that the requirements for heat exchanger systems

should be deleted. The commenter stated that the EPA has not justified the high costs of

sampling that would be required by the proposed rule; however, if sampling is required, the

proposed reference to subpart F is the most reasonable available. Commenter IV-D-28 supports

the decision to use the HON requirements for heat exchangers, but believes the rule should

simply cross-reference the HON, not modify and spread out the requirements among the

standards, compliance, monitoring, recordkeeping, and reporting sections of this rule. If the final

rule is not revised to cross-reference subpart F, Commenter IV-D-28 requested that EPA correct

the last sentence in § 63.1362(g)(3) to be consistent with the HON. Specifically, the commenter

stated that the word “and” should be deleted from the phrase “ion specific electrode monitoring,

pH, and conductivity or other representative indicators” because only one surrogate indicator is

needed, not all of them.

Response: The EPA disagrees with the commenter’s assertion that the heat exchanger

system provisions impose a high cost for sampling. The rule allows considerable flexibility in

the type of sampling or other monitoring that an owner or operator may perform, and the amount

of required sampling or monitoring is minimal. The owner or operator may elect to sample for

one or more HAP or other substances whose presence in the cooling water indicates a leak. 

Alternatively, the owner or operator may elect to monitor for any surrogate indicator that reliably

identifies the presence of a leak. If the owner or operator elects to comply by monitoring for a

surrogate indicator, the owner or operator must develop a plan that specifies what parameter or

condition will be monitored, the level that constitutes a leak, and an explanation of how the
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selected parameter or condition will reliably identify a leak. In the first year, sampling or

monitoring is required eight times; in subsequent years, sampling or monitoring is required only

four times per year. If the heat exchangers are all part of a single system, only one set of inlet

and outlet samples are required. These requirements also are not considered burdensome

because many facilities in the chemical processing industry, and presumably the PAI production

industry as well, conduct such sampling or monitoring as a common maintenance practice. 

Furthermore, sampling for the detection of heat exchanger system leaks is a general requirement

of some State permits (e.g., Texas Natural Resources Conservation Commission). 

The Agency agrees with the comment that cross referencing the heat exchanger

provisions in subpart F of the HON would simplify the rule. Therefore, as noted in the response

to the first comment in section 20.3 of this document, the final rule cross-references all of the

heat exchanger system provisions in subpart F rather than incorporating some of the provisions in

the rule and cross-referencing others. However, the heat exchanger system provisions are

contained in more than one section in the PAI rule because this rule is structured differently from

the HON. In the HON, all of the requirements for a specific type of emission point were

presented in a single section or in consecutive sections. In the PAI rule, the standards for all

types of emission points are presented in one section, the initial compliance provisions for all

types of emission points are presented in the next section, and so on. Therefore, each section in

the final rule cross-references the appropriate heat exchanger system provisions from subpart F. 

This change also corrects the editorial error that one commenter identified.

6.2 OUTLET CONCENTRATION STANDARDS

Comment 1: Commenters IV-D-16 and IV-D-27 requested that the 20 ppmv outlet

concentration standards be the same for all existing and new source process, storage tank, and

wastewater vents and that they be based on both TOC and total organic HAP. The commenters

requested this clarification because § 63.1364(d)(5) of the proposed rule only used organic HAP,

and § 63.1364(c)(1)(viii) only used TOC. The commenters also asked for clarification that TOC

excludes methane and ethane. Commenter IV-D-27 requested that the 20 ppmv concentration

apply to both uncontrolled and controlled vents.
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Response: The Agency agrees with the commenters that the 20 ppmv compliance option

should be the same for all emission streams at both new and existing sources. In the final rule,

the control device (or last control device in series) must achieve an outlet, undiluted TOC

concentration of 20 ppmv or less, as calibrated on methane or the predominant HAP. The

reference to organic HAP in § 63.1364(d)(5) of the proposed rule was an error. The intent at

proposal was that the standards would be based on TOC for all emission points; in addition, for

wastewater emissions, the standard included total organic HAP as well as TOC because the

wastewater provisions were based on the HON. To make the standards consistent for all

emission points, the final rule states that when the phrase “TOC concentration or total organic

HAP concentration” is used in §§ 63.139 and 63.145, the phrase “TOC concentration” applies for

the purposes of the final rule.

The final rule also includes the option to subtract out methane and ethane from the TOC

concentration. Though sources have this option, EPA believes the use of a continuous TOC

analyzer, such as a FID, will be complicated by having to subtract out methane and/or ethane. 

Because the inclusion of methane and ethane, which should only be significant for combustion

devices, will only yield a higher TOC value, the simplification of the method to use a continuous

FID without such a correction is allowed for all devices.

Lastly, the final rule also specifies that uncontrolled emission streams containing less than

20 ppmv HAP are not considered to be process vents subject to the control requirements in the

rule. This provision is incorporated in a revised definition of “process vent,” as described in the

response to comment 8 in section 5.2.

Comment 2: Commenter IV-G-03 contends that the standards are arbitrary and

capricious because smaller producers will be forced to comply with the 98 percent reduction

requirement, whereas larger producers are more likely to be able to comply with the “volume

limitation,” which the commenter believes is less stringent. Commenter IV-D-17 stated that the

limits proposed in the rule are readily achievable using proven, commercially available

technologies.

Response: The EPA does not understand what the commenter means by the volume

limitation, or why small producers are at a disadvantage to large producers. The process vent
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standards require either 98 percent reduction or control to an outlet concentration of 20 ppmv for

individual vents that meet certain flow rate and HAP load thresholds. New source standards also

specify either 98 percent reduction or control to an outlet concentration of 20 ppmv. Possibly the

commenter believes the 20 ppmv outlet concentration option is less stringent than the 98 percent

reduction requirement. This is true if the uncontrolled concentration is less than 1,000 ppmv. 

However, the uncontrolled concentration is a function of the individual production process,

which may be operated by either a small producer or a large producer. Furthermore, the rule

prohibits intentional dilution as a means of achieving this outlet concentration standard. Finally,

the 20 ppmv limit is not intended to be a less stringent option; it is simply a recognition that

20 ppmv is the practical limit of control for control devices.

6.3 COMPLIANCE OPTIONS

Comment 1: Commenter IV-D-28 requested that the final regulation allow owners and

operators to comply by routing emissions to a fuel gas system or to a process, as in the HON. 

Commenters IV-D-21 and IV-D-29 requested that EPA exempt from regulation all gaseous

streams routed to fuel gas systems by changing the definition of process vent to match the HON. 

Response: The EPA has not changed the final rule to allow compliance by routing

streams to fuel gas systems. Under the HON, a fuel gas system is defined as a combustion

device. One common type of combustion device is a boiler. The final rule already contains

requirements for boilers as control devices. Therefore, to avoid the confusion of whether the

owner or operator should comply with requirements for boilers or fuel gas systems, the final rule

contains provisions only for boilers. However, for large boilers (>44 megawatts [MW]), there

are no performance testing or monitoring requirements, which is the same outcome as allowing

compliance via fuel gas systems.

The HON allows emissions from storage vessels to be routed to a process. Specifically,

the owner or operator must conduct a design evaluation to demonstrate that such emissions

predominately meet one or more of the following ends: recycled and/or consumed in the same

manner as a material that fulfills the same function in that process, transformed by chemical

reaction into a material that is not a HAP, incorporated into a product, or recovered. The EPA

agrees that routing emissions from a storage vessel to a process is also acceptable for storage
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vessels in the PAI source category, and the final rule has been revised accordingly. However, the

provisions in the PAI final rule differ from the HON in two ways. First, the recovery option is

not included because, as noted in the response to the comment in section 3.4, the concept of

recovery as used in the HON is not used in the PAI final rule. Second, the design evaluation

must demonstrate that less than 5 percent of the HAP routed to the process are ultimately

emitted; otherwise, routing to a process is less stringent than routing to a control device.

Comment 2: Commenter IV-D-28 stated that if emission streams from different types of

vents (i.e., process vents, storage vessels, and wastewater) are all manifolded to a common

device, the rule should specify which requirements take precedence. For example, the

commenter stated that under the HON, the owner or operator may comply with the first

applicable set of requirements from the following hierarchy: process vents, transfer racks,

storage vessels, waste management units, and in-process equipment subject to § 63.149.

Response: For situations in which different streams are manifolded into the same control

device, the owner or operator would have to demonstrate that the device meets the most stringent

control efficiency applicable to the emission sources. In the HON, the control level required for

process vents and transfer racks was highest, at 98 percent, followed by 95 percent control for

storage and wastewater emission sources. Therefore, in a situation where all types of emission

streams would be manifolded to a device, the “hierarchy” would be according to process vents

and transfer racks, followed by storage and wastewater, because process vents and transfer racks

require higher control efficiencies.

6.4 ROUTINE MAINTENANCE

Comment: Several commenters (IV-D-16, IV-D-21, IV-D-27, IV-D-28, and IV-D-29)

requested either an extension in the 240 hr/yr allowance for routine maintenance or greater

flexibility in its application. Commenter IV-D-27 suggested that EPA allow up to a 30-day

extension for control devices (like RCRA incinerators) that require more than 10 days of

maintenance per year, or allow a facility to compensate for longer downtime by overcontrolling

at other times (this would also require a change in the compliance averaging period–see

comments in section 7.5 of this document). In addition, commenters IV-D-21 and IV-D-29

recommended that the 240 hr/yr be allowed for each PAI process unit because maintenance may
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be required prior to each campaign. Alternatively, commenter IV-D-29 suggested that, based on

standard maintenance work practices, the startup, shutdown, and malfunction requirements in

subpart A of part 63 should be allowed in lieu of the proposed 240 hr/yr time period. 

Commenter IV-D-29 explained that the standard work practice for many companies is to isolate

all equipment upstream of control devices where planned maintenance will occur to eliminate all

safety hazards to personnel and minimize any impact to the environment. Commenter IV-D-28

supported the provision, but suggested it be expanded to cover controls for waste management

units, controls used on equipment leaks, and recovery devices (if applicable).

Response: The proposed 240 hr/yr for planned routine maintenance was mistakenly

applied to all control devices in the proposed rule; it should only have been applied to storage

vessels. The startup, shutdown, and malfunction provisions prohibit the shutdown of control

devices during operation; however, EPA recognizes that for storage vessels, it is impossible to

“not operate” (i.e., not have breathing losses) during a period of time in which an add-on control

device would be undergoing planned maintenance. Therefore, EPA has in the final rule allowed

an amount of time (240 hr/yr) in which the control devices for storage vessels only can be nonoperational due to planned routine maintenance. All other situations (i.e., those that require

unplanned, emergency maintenance) should be addressed through the startup, shutdown, and

malfunction provisions. This change makes the final rule consistent with other MACT standards. 

The rationale for the 240 hr/yr allowanceis that EPA determined that routine maintenance for

certain control devices may take as much as 10 days to complete, and that this time frame is

consistent with State permitting activities (see 59 FR 19441 for a more detailed discussion of the

time allowance).

6.5 MACT AND MACT FLOOR

Comment: Commenter IV-D-28 stated that the 20 surveyed plants represent only

26 percent of the estimated number of affected sources; thus, it is possible that EPA may not

have collected data representing the best controlled source, the best controlled 12 percent of

existing sources, and the impacts of going beyond the floor for each of the initial source

categories and the combined source category. The commenter suggested that it is possible that

EPA has no data at all on many of the source categories that were combined in the proposed rule. 
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Commenter IV-D-28 also stated that the applicability thresholds for process vents and storage

vessels are tiny. The commenter had not determined whether the thresholds were for the floor or

options more stringent than the floor, but either was a concern. For example, if they are for the

floor, the commenter believes it is likely that they are from facilities that are not major sources

due to PAI operations alone and if so, the floor should not be based on them. Alternatively, if

they are for options more stringent than the floor, the commenter believes the resulting cost

effectiveness values must be in a range that has been considered unacceptable for other

standards.

Response: Some of the above comments imply that the database that was used to

determine the MACT floor is not representative of the industry. The EPA acknowledges that

data are not available for every process included in the source category, nor for every affected

source. However, EPA believes the processes at the surveyed plants are representative of all

processes in the source category, that the surveyed plants include the best controlled plants in the

source category, and that using the data from the surveyed plants to develop the MACT floor is

appropriate. 

The response to the comment in section 3.1 describes a few changes that have been made

since proposal to exclude from the source category some processes that are not representative of

those that were surveyed. Because the remaining processes are believed to have similar product

use, process unit operations, types of HAP emitted, emission rates, and controls, they were

combined in a single source category. As a result, separate evaluations of each process (or each

initial source category) are unwarranted. 

Although only a subset of the estimated total number of affected facilities in the entire

source category were surveyed, the MACT floor was based on actual data obtained from a

number of facilities, nine, that is equal to 12 percent of the total number of affected facilities in

the source category. Even if data from the entire source category had been collected, the MACT

floor dataset would still consist of nine facilities. In addition, because EPA strived to identify

and survey the best controlled sources, as described in the Basis and Purpose document, EPA

believes that the surveyed facilities include both the best controlled source and the best

performing 12 percent of existing sources. The EPA also rejects the notion that facilities whose
6-8

PAI processes alone do not exceed the major thresholds should not be part of the MACT floor. 

The EPA’s implementation of the definition of major source, which requires the aggregation of

all HAP emissions within a plant site, was affirmed in a July 21, 1995 D.C. Circuit Court

decision (National Mining Association vs. U.S. Environmental Protection Agency), where NMA

had challenged EPA’s definition of a major source. Thus, EPA believes the MACT floor

developed from the survey data is representative of the source category.

Finally, the standard was based on regulatory alternatives more stringent than the MACT

floor only when the cost was determined to be reasonable. For storage vessels, the standard is

based on the MACT floor because no alternative was determined to be cost effective. For

process vents at existing sources, the standard is more stringent than the floor for certain large

vents for which control at 98 percent was determined to be cost effective. The standard for all

other process vents at existing sources and at new sources is based on the MACT floor.

6.6 CLARIFICATION

Comment: Commenter IV-D-28 noted that § 63.1362(a) of the proposed rule

requires control of HAP emissions to the level specified in Table 2 and paragraphs (b) through

(g). The commenter stated that because these are not different sets of requirements, it would be

better to require control of HAP emissions “to the levels specified in paragraphs (b) through (g),

as summarized in Table 2.

Response: The EPA agrees with the commenter, and has made the suggested change in

the final rule.
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7.0 STANDARDS-PROCESS VENTS

7.1 MACT AND MACT FLOOR

Comment 1: Three commenters (IV-D-26, IV-D-20, and IV-D-27) requested that sources

be able to use vents meeting the criteria for 98 percent control in determining 90 percent overall

process control requirements. Commenters stated that EPA determined that the MACT floor was

90 percent on a process wide basis. Commenter IV-D-16 also indicated that vents required to be

controlled to 98 percent should be used in establishing the overall 90 percent reduction for the

process because the data analysis supporting the MACT floor for existing sources (90 percent

reduction requirement for process vents) is based on control achieved on all process vents by the

best controlled 12 percent of all processes. According to commenter IV-D-27, excluding these

vents increases the stringency of the floor.

Response: The MACT floor was determined to be 90 percent control for process vents at

existing sources. In addition to the MACT floor, the EPA is required to develop regulatory

alternatives beyond the floor and to select MACT based on the cost effectiveness of these

alternatives. For specific process vents, Regulatory Alternative 1 would require 98 percent

control efficiency, i.e., those vents that meet the flow and annual uncontrolled emissions criteria 

described in § 63.1362(b)(2)(iii) of the final rule, and would require 90 percent control efficiency

for the sum of emissions from all other vents within the process. The cost of Regulatory

Alternative 1 was judged to be acceptable, and this alternative was selected as MACT. The EPA

agrees that this requirement is more stringent than the floor. If a vent that must be controlled to

98 percent is included in determining 90 percent control for all process vents within the process,

the owner or operator would only be complying with the MACT floor, not the more stringent

regulatory alternative. Thus, the final rule does not allow an owner or operator to use process
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vents that are subject to the 98 percent control requirement in determining compliance with the

90 percent overall control level for the sum of other process vents in the process.

Comment 2: Commenters IV-D-21 and IV-D-29 stated that the data used to set the

98 percent level of performance was obtained during off-line tests during which liquids (for the

most part hazardous waste surrogates) were burning during continuous injection. Furthermore,

the commenters stated that there were no data for the efficiency of combustion of dilute

concentrations of gaseous HAP streams emitted from batch processes in a discontinuous fashion. 

The commenters believe that EPA has insufficient data to support the establishment of a PAI

batch process combustion control equipment MACT floor. Commenters suggested that EPA

should reexamine this control requirement, and determine a true MACT floor based on testing

that is conducted on actual batch processes, over the typical 1-hour batch cycle times, with

gaseous vent line concentrations ranging from 100 percent HAP down to 1 lb/yr HAP.

Response: Some of the surveyed PAI manufacturing facilities reported control

efficiencies for RCRA incinerators that were based on performance tests conducted for liquid

burning, and these facilities all reported control efficiencies that exceeded 98 percent. Although

these data were not from tests conducted when only gaseous streams were incinerated, a

considerable amount of performance testing for thermal incinerators has been conducted over the

years. Based on these tests, EPA has concluded that incinerators that operate above certain

temperatures and with certain residence times consistently achieve 98 percent emission reduction

or, if inlet concentrations are low, to an outlet concentration of no more than 20 ppmv. Typical

operating temperatures for the RCRA incinerators in the PAI data base are at least 1800EF and

residence times are in the range of 1 to 3 seconds. Because these temperatures and residence

times are higher than would be expected for a typical thermal incinerator, it is expected that these

RCRA incinerators also achieve at least 98 percent for process vent streams. Therefore, EPA

believes the 98 percent control efficiency assigned to RCRA incinerators in the MACT floor

analysis are reasonable.

Comment 3: Commenters IV-D-16 and IV-D-27 noted an inconsistency that should be

resolved. The commenters pointed out that in the proposed standards, integral intermediate

processes are combined with PAI processes to define a single “process,” but they were evaluated
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separately in the MACT floor analysis. Commenter IV-D-27 further noted that this change

would result in an increase in the applicability cutoff of the MACT floor because part of the

emissions from intermediate process No. 36 should be combined with the emissions from active

ingredient process No. 35 that had the lowest uncontrolled emissions and was used to establish

the applicability cutoff of 0.15 Mg/yr.

Response: The response to the comment in section 3.3 describes changes in the final rule

to clarify the definitions of “integral intermediate” and “process.” That response explains that

the intent in the proposed rule was to consider production of integral intermediates to be separate

processes. As the commenters noted, this is also the approach used to develop the MACT floor.

As a result, EPA has not changed the basic approach used to develop the MACT floor. However,

in re-examining this approach since proposal, EPA realized that some of the active ingredient

processes at the surveyed facilities included production of intermediates; in addition, some of the

reported intermediate processes may satisfy one of the criteria for storage and thus not be integral

intermediates. If all of the intermediates are integral intermediates, the floor would increase to

92 percent. If none of the intermediates are integral intermediates, the floor would decrease to

88 percent. Thus, EPA considers the proposed floor of 90 percent control to still be appropriate. 

The applicability cutoff also is unchanged because the active ingredient production and

intermediate production are not combined into a single PAI process unit.

Comment 4: Commenter IV-D-15 stated that the control technologies at their facility

were “taken out of context” and inappropriately used in the MACT floor calculation. The

commenter stated that their intermediate process is not representative of other processes within

the PAI industry; in addition, it may not be an “integral intermediate,” depending on what

“storage” means (the intermediate could be stored from several hours to several days prior to the

active ingredient process). The commenter stated that the regulation would require burdensome

administrative requirements that do not result in emission reductions, and the equipment required

for control of volatile organic HAP is prohibitively expensive ($48,500/ton of HAP removed). 

Response: While the commenter indicates that their intermediate and active ingredient

processes are not “representative,” these processes are located at a MACT floor facility (i.e., the

top 12 percent of sources). The commenter’s basic concern for the active ingredient process is
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that both gaseous HAP and particulate HAP are emitted from the process, and particulate HAP is

well controlled. Good control of particulate HAP at this plant provides a high overall control

efficiency and is the factor that makes it a MACT floor plant. While the control efficiency for

particulate HAP is high, it is not included in the MACT floor calculation for process vents for

organic HAP. It is also important to remember that the presence of multiple planks for a process

(i.e., process vents, storage tanks, equipment leaks, wastewater, and product dryers) varies

throughout the industry from process to process. For example, some processes emit HAP from

process vents and wastewater but not from the other three planks. In addition, use of product

dryers in the PAI industry is common. At the commenter’s facility, the product dried is a HAP

compound, and HAP is emitted from the process and controlled; these uncontrolled and

controlled emissions would be included in the overall HAP emission calculation at the facility

just like any other plank. At other facilities, however, the product dried was not a HAP and there

were no HAP emissions from this process step. See chapter 6.5 for additional discussion. 

The commenter’s concerns regarding the intermediate process are related to the fact that

it is a single vent with low flow that is controlled with a flare. While this may not be

representative of all processes in the industry, it is important to remember that this intermediate

process in and of itself is not the basis for the MACT floor for existing source process vents, but

was included in the average control efficiency calculation along with other processes at the

MACT floor facilities. The commenter expressed concern regarding the control costs not being

representative either (i.e., a flare is a less expensive control device than some other devices and is

not technically feasible for all processes). However, flare costs were not estimated for control of

process vents, and the cost to control this particular process vent was not determined directly

anyway. Model streams were developed based on “average” streams in the industry that are

subject to the standard, and the cost to control these model or average streams was estimated for

thermal oxidizers and condensers. See chapter 19 for additional discussion of costs and impacts.

7.2 APPLICABILITY CUTOFFS

Comment 1: Commenters IV-D-16, IV-D-20, and IV-D-27 requested that an

uncontrolled emission concentration cutoff of 50 ppmv be established for existing and new

sources (to be demonstrated on either a HAP or a TOC basis). According to
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commenter IV-D-27, this could be done by revising the definition of Group 1 process vent or by

creating an exemption in § 63.1360(d)(4). According to commenter IV-D-16, this would be a

powerful incentive for some sources to fully implement pollution prevention practices to achieve

compliance. Commenters IV-D-16 and IV-D-27 indicated the cutoff (or Group 1 process vent

definition) should also include a cutoff of 0.005 standard cubic meters per minute (scmm).

Commenters IV-D-21, IV-D-27, and IV-D-29 stated that to be consistent with the HON,

EPA should set an applicability cutoff based on “total resource effectiveness” that would provide

incentives for sources to implement pollution prevention practices (such as product recovery

devices) in order to avoid triggering process vent standards. Commenters IV-D-21 and IV-D-29

recommended that the flow rate and concentration cutoffs from the HON process vent definition

be used.

Response: Under the proposed rule, the applicability cutoff of 0.15 Mg/yr of HAP per

process was contained in the definition of Group 1 process vent. For the final rule, the definition

of “process vent” was revised to exclude streams containing less than 20 ppmv HAP, and the

definition of “Group 1 process vent” was revised to include a mass cutoff of 6.8 Mg/yr for total

hydrogen chloride and chlorine emissions as well as the 0.15 Mg/yr cutoff for organic HAP

emissions. The rationale for changes to these definitions is provided in the response to

comment 8 in section 5.2.

It is not clear that the higher cutoffs suggested by the commenters would lead to increased

implementation of pollution prevention practices (and it certainly would not result in increased

compliance with the pollution prevention alternative in the rule). However, higher cutoffs would

result in lower overall control efficiencies, which would be inconsistent with the MACT floor. 

Finally, as noted in the response to the comment in section 3.4, the concept of recovery devices,

as used in the HON, was not intended to be in the proposed rule and is not in the final rule.

Comment 2: Commenter IV-D-15 suggested a higher threshold level (greater than or

equal to 0.15 Mg/yr) needs to be developed either for a process as a whole or for the individual

process entities that make up the commenter’s Captan process. Commenters IV-D-16 and

IV-D-20 stated that the process mass emissions cutoff should be set at 2,000 lb/yr and be

applicable to both controlled and uncontrolled emissions. The commenters stated that to account
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for the limited nature of the PAI data base, EPA should use 2,000 lb/yr process cutoff that was

established for the proposed Pharmaceutical MACT standards. In addition, the commenters

stated that a 330 lb/yr cutoff is far lower than the 10,000 lb/yr cutoff that was determined to be

the cost effective cutoff in the Batch Processes Alternative Control Techniques (ACT) document. 

Commenter IV-D-27 stated that the applicability cutoff for process vents should be set at

10,000 lb/yr (or higher) as was done in the Batch Processes ACT document; this is the minimum

value for which 90 percent control was determined to be cost effective. The commenter noted

that in many cases, controls on processes with small HAP emissions were added for odor control

or VOC’s. The commenter disagreed with EPA’s assertion during Partnership group meetings

that the CAA does not allow the Agency to consider the reason controls were added. 

Specifically, the commenter states that there is no statutory limitation on how EPA defines the

“affected source”; for example, EPA has already provided exclusions in § 63.1360(d), and a

higher applicability cutoff could be another. Commenters IV-D-16 and IV-D-28 claim that the

lack of meaningful cutoffs for existing and new source process vents will discourage pollution

prevention (because if pollution prevention doesn’t reduce emissions below cutoffs, it will be

become more difficult to meet the required percent reduction from the lower starting point) and

result in disproportionate impact on process vents with extremely small emissions; other MACT

standards exclude low flow and low HAP to mitigate this concern.

Response: The EPA attempted to collect information on the best controlled facilities in

the PAI industry; EPA believes that the best controlled facilities are contained in its PAI data

base and that the processes contained in the data base are representative of the industry. Based

on the PAI data base, many processes with uncontrolled emissions that were significantly less

than the cutoffs mentioned by the commenters were controlled to levels of 90 percent or greater. 

Because the emission cutoffs mentioned by the commenters were not supported by the process

vent data, these cutoffs would not have been defensible because they would have been less

stringent than the cutoff prescribed by the MACT floor.

The commenters indicate that the cutoff determined at proposal is not cost effective and

suggested other cutoffs that have been demonstrated as cost effective. However, there is no

provision in the amended CAA for consideration of cost effectiveness in setting the MACT floor. 
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Therefore, it is conceivable that the standards, which are set based on the practices of the

industry, will require a level of control that is greater than what was determined to be cost

effective for other CAA programs. For example, the 10,000 lb/yr cutoff contained in the draft

Batch Processes ACT that was referenced by the commenters was intended to simplify

applicability of presumptive Reasonably Available Control Technology (RACT) control

measures, which are applied to the reduction of criteria pollutants (in this case, VOC’s), and can

include the consideration of cost effectiveness. 

Finally, the amended CAA also contains no provisions for considering reasons why

certain processes are controlled and others are not in assembling the group of sources that will

make up the best 12 percent of the source category. Therefore, the issue of facilities controlling

HAP’s for odor control or other purposes is not a consideration in setting the floors. 

Comment 3: Commenter IV-D-28 also noted that, unlike other regulations, many of the

process vent provisions apply to a collection of vents rather than to individual vents. The

commenter is unsure whether the collective approach will work and stated that the rule should

also include an option that allows for the determination of Group status for each individual vent

and control of emissions on a vent-by-vent basis.

Response: The Group 1 process vent emissions cutoff (i.e., 0.15 Mg/yr) was determined

based on the uncontrolled HAP emission level from the collective or entire process, not on an

individual vent basis. The rule allows an applicability determination for an individual process

vent based on a concentration cutoff; emission streams containing less than 20 ppmv HAP are

not considered process vents. 

Comment 4: Commenter IV-G-01 asserted that the applicability equation found in

§ 63.1362(b)(2)(iii)(A) used to determine which vents must be controlled to 98 percent is

inappropriately applied to batch operations. The commenter explained that the flow rate used in

the computer model to develop the 98 percent applicability regulatory alternative (Batch

Processes ACT) is a constant flow rate, which is inconsistent with batch processing.

Response: In the Batch Processes ACT, EPA developed costs for an incinerator to

estimate the cost effectiveness of controlling emissions from batch process vents. Although flow

rates from batch processes vary, the control device must be capable of handling the maximum
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flow rate possible. Therefore, the incinerator was sized and costed for the maximum flow rate

that occurs from the process, even though venting from batch processes will include periods of

lower flow rates.

7.3 HCl STANDARDS

Comment 1: Commenters IV-D-21 and IV-D-29 are concerned that EPA’s approach to

determining the MACT floor for the HCl emission limit criteria (e.g., the 6.8 Mg/yr cutoff) in

§ 63.1362(b)(3) of the proposed rule considers only a limited number of process vents emitting

HCl which may not be representative of the entire source category. The commenters recommend

that EPA consider setting the HCl cutoff for existing sources at least as high as the average of the

two lowest HCl emission rates from controlled processes at the MACT floor facilities (i.e.,

(6.8 Mg/yr + 11.0 Mg/yr)/2 = 9.0 Mg/yr), or that the control device for the process vent emitting

HCl meet a minimum 90 percent efficiency if installed and in operation before November 7,

1997. (Note: EPA assumes the commenter means the proposal date of November 10, 1997.) 

The commenters believe these changes will improve incentives for pollution prevention, and

allowing 90 percent control would reduce the cost burden on existing facilities because

retrofitting to achieve an incremental improvement in control is very expensive.

Response: The EPA disagrees with the commenter that the proposed cutoff for HCl

emissions is inappropriate. As described in the Basis and Purpose document and summarized

below, EPA believes the cutoff of 6.8 Mg/yr is a very clear and obvious breakpoint. Also, even

though the MACT floor plants have fewer processes with HCl emissions than organic HAP

emissions, this is representative of the industry as a whole. Thus, one would expect that the HCl

floor would be based on less data than the floor for organic HAP emissions. The EPA also notes

that if the floor were determined by evaluating the best controlled processes throughout the

industry rather than the processes at the best performing 12 percent of existing facilities that the

applicability cutoff might be lower than 6.8 Mg/yr. It certainly would not be higher.

To develop the MACT floor for the proposed rule, all of the processes at the nine MACT

floor facilities were ranked by uncontrolled HCl emissions. All processes with uncontrolled

emissions below 6.8 Mg/yr were uncontrolled, and processes with higher emissions were
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controlled to various levels. Therefore, the MACT floor was determined to be no control for

processes below this threshold, and 94 percent for processes above it.

The EPA believes there is no basis for setting a cutoff at 9.0 Mg/yr or for setting a control

level of 90 percent for control devices installed before November 10, 1997. Because the MACT

floor consists of both a control efficiency and a cutoff, the cutoff cannot be changed

independently of the control efficiency. A cutoff of 9.0 Mg/yr would be inappropriate because it

is not associated with the determined MACT floor control efficiencies. Furthermore, it would

not make sense to include one controlled process (i.e., the process with emissions of 6.8 Mg/yr)

in the group with all of the uncontrolled processes; this is a very clear and natural cutoff. If the

standard were based on an alternative more stringent than the floor, the rule might allow

emission points that are already controlled to the level of the MACT floor to comply with that

level (as was done for organic emissions from process vents). However, there is no basis for a

90 percent control level, regardless of the installation date, because the 94 percent control level

for HCl is the MACT floor. Finally, the EPA recognizes that the incremental cost effectiveness

will be high for a facility with control just below the required level. However, this would be true

no matter where the level was set. 

Comment 2: Commenters IV-D-16 and IV-D-27 stated that the HCl standards for new

sources should be set at 99 percent removal for consistency with the HON requirements. 

Commenter IV-D-27 stated that since there is no actual test data from the pesticide

manufacturing industry demonstrating a 99.9 percent removal of HCl; a change to 99 percent

would provide consistency with HON rule requirements.

Response: The EPA agrees with the commenters. The proposed control level was based

on a value reported by a surveyed facility. This value was not supported by test data or other

documentation. However, a control level of at least 99 percent is likely for this scrubber because

HCl control levels of 99 percent are widely accepted as achievable by scrubbers, and several

other facilities reported this level. Therefore, for the final rule, the required control level for new

sources has been changed to 99 percent. Although being consistent with the HON is not a

priority, this change, as one commenter observed, does make the two rules consistent.

7.4 COMPLIANCE AVERAGING PERIOD
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Comment: Commenter IV-D-27 stated that the process vent standards should be based

on “annual average” removals to reflect the data used in developing the standards. The

commenter stated that these data were annual values that mask variability in uncontrolled

emissions (especially for batch processes) and control device operating parameters, thus, it is

unreasonable to expect that the annual efficiency can be met on a daily basis.

Response: The EPA believes that the data used to develop the MACT floor are consistent

with compliance determinations over 24-hour periods (or, as allowed in the final rule, the

duration of a batch process). One consideration is that emission stream conditions from batch to

batch should be essentially the same. Even if temperatures, reaction times, purge flows, or other

operating characteristics varied slightly from one batch to the next, EPA assumes that the

reported annual uncontrolled emissions for the MACT floor facilities were calculated, quite

logically, assuming identical emissions for each batch of a given process. A second

consideration is the reported control efficiencies for most of the control devices were values that

likely are consistent from day-to-day. For example, many of the processes are controlled with

combustion devices, which operate with a consistent reduction efficiency. For other devices

(e.g., a condenser), it is likely that the efficiency varies for different episodes, but if emissions for

a given episode are consistent from one batch to the next (as described above), the control

efficiency for that episode should also be consistent, assuming the control device operating

parameters are consistent. There may be a few situations where control parameters vary for a

given emission episode over the course of a year (e.g., if a control device is used only part time

or if the vents manifolded to the control device change as the mix of processes change). At the

MACT floor plants, several processes are known to be subject to part-time control, but EPA has

no evidence of changes in control settings for different combinations of manifolded vents. 

Processes subject to part-time control that have average control efficiencies below the level of

the standard are no different from processes with a consistent control level below the level of the

standard; both must implement additional control. The response to the comment in section 16.1

presents rationale for monitoring on a daily or block basis.

7.5 OVERLAP WITH OTHER STANDARDS
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Comment: Commenter IV-D-27 requested that EPA specifically state that regulated

emissions from pesticide manufacturing process vents that are routed to Resource Conservation

and Recovery Act (RCRA) incinerators are deemed to comply with the standards of this rule with

no additional performance testing, monitoring, recordkeeping, or reporting requirements.

Response: The proposed rule exempted an owner or operator from performance test

requirements for RCRA control devices, and this provision has been retained in the final rule. In

addition, the final rule exempts the owner or operator from monitoring, recordkeeping, and

reporting provisions when emissions are routed to a RCRA control device.

7.6 CLARIFICATIONS

Comment 1: Commenter IV-D-28 asserted that § 63.1362(b)(2)(iii)(B) of the proposed

rule allows an owner or operator to demonstrate that a control device was “designed” to reduce

organic HAP emissions by between 90 and 98 percent; however, the commenter suggests that the

focus should be on the reduction the device is capable of achieving instead of its design. The

commenter has a similar concern on § 63.1362(c)(1)(ii) of the proposed rule. 

Response: The Agency agrees with the commenter regarding the term “design” of a

control device. This subparagraph in both § 63.1362(b) for process vents and (c) for storage

tanks has been revised to include “If the owner or operator can demonstrate that a control device

installed on a process vent subject to the requirements . . . on or before November 10, 1997

reduces inlet emissions of total organic HAP by greater than or equal to 90 percent but less than

98 percent . . . ”

Comment 2: Commenter IV-D-16 stated that the flowrate equation in

subparagraph 63.1362(b)(2)(iii)(A) of the proposed rule should be revised to contain a “less than

or equal to” sign rather than an “equal to” sign to agree with the regulatory text.

Response: The equation in § 63.1362(b)(2)(iii)(A) of the proposed rule for the flow rate

is correct. For the 98 percent requirement to apply, the actual weighted average flow rate for the

vent must be less than or equal to the flow rate calculated using this equation. In the final rule,

an additional equation for determining the weighted average flow rate for the vent has been

added.
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7.7 REQUIREMENTS FOR SURGE CONTROL VESSELS AND BOTTOMS RECEIVERS

Status at proposal. Under the proposed rule, emissions from surge control vessels and

bottoms receivers would be regulated as process vents. This approach differs from the HON,

which regulated these emissions under subpart H. Because the equipment leak standards in the

proposed rule also cross-referenced subpart H, the proposed rule specified that the provisions for

surge control vessels and bottoms receivers in subpart H would not apply.

Comment: Commenter IV-D-28 opposes the proposed requirement to regulate surge

control vessels and bottoms receivers as process vents because it introduces a third way to

regulate such emissions under the MACT standards. The commenter would prefer that these

emissions be regulated as equipment leaks, as under the HON. If that is not acceptable, the

commenter’s second choice is to regulate the emissions as storage vessels, as under P&R IV. 

The commenter believes that additional inconsistency is confusing and likely to lead to

inadvertent compliance mistakes.

Response: The EPA notes that there is essentially no difference between regulating

emissions from these equipment as “equipment leaks” (as in subpart H) versus as “storage tanks”

(as in subpart G). Both the applicability and control requirements for these sources in the HON

are identical. The reason EPA departed from this rationale in the proposed rule, is that surge

control vessels and bottoms receivers typify the processing equipment, in capacity and function,

found in these industries. Especially in the case of batch processing (where the HON does not

regulate process vents), the characteristics of emission streams from these equipment are not

significantly different than any other equipment. Emission streams from bottoms receivers and

surge control vessels result from the displacement of saturated gases from incoming materials. 

Displacement emissions are very common in both the pharmaceuticals and this industry. 

Therefore, EPA decided to regulate them in a manner consistent with the remainder of processing

equipment found in these industries.

In response to the commenter’s concern about possible confusion from the inconsistent

application of requirements across different source categories, EPA believes that the consistent

treatment described above will actually eliminate a great deal of confusion in the implementation

of the rule, because all equipment associated with a process will be treated in the same manner,
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and the control requirements, which are process based, can be evaluated over all equipment in the

process. Additionally, because of the similarities of these equipment with other process vessels,

the confusion related to defining a surge control vessel or bottoms receiver from another process

vessel will also be averted.
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8.0 STANDARDS-STORAGE VESSELS

8.1 STORAGE VESSEL MACT FLOOR

Status at proposal: Under the proposed rule, the MACT floor for storage vessels

consisted of applicability cutoffs and a control efficiency for vessels that exceeded the cutoffs. 

To develop the floor, the storage vessels at the best performing 12 percent of facilities were

ranked by decreasing uncontrolled emissions. The vessels were divided into two groups based

on an uncontrolled emissions cutoff below which the median control efficiency was no control. 

This cutoff was 108 kg/yr, and the median control above the cutoff was 41 percent. A vessel size

cutoff was established at 38 m based on the smallest vessel with uncontrolled emissions greater 3

than 108 kg/yr that was controlled at least to 41 percent. For new sources, the smallest vessel

with the best level of control was determined. The floor for new sources was determined to be

98 percent control efficiency for storage vessels 26 m or greater with uncontrolled emissions of 3

at least 0.45 kg/yr.

Comment: Commenter IV-D-27 stated that the control levels originally provided by the

commenter for Tank Nos. 10 and 15 are inaccurate due to incorrect coolant temperatures used by

the commenter. The commenter stated that the impact of this change is that the existing source

MACT floor based on the median control level for vessels with greater than 240 lb/yr of

uncontrolled emissions becomes 21 percent (now based on Tank No. 10 instead of Tank No. 15),

instead of 41 percent. Commenter IV-D-14 stated that the new source MACT floor should be

revised to include consideration of vapor pressure of the stored HAP to be a primary parameter.

Response: The EPA has corrected the control efficiencies for each of the storage vessels

mentioned by the commenter. The EPA also reexamined the data base since proposal and

removed several vessels that should not have been included because they do not meet the
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definition of storage vessel. Changes to the storage vessel data base, and changes to the MACT

floor and the final standard that are summarized in the remainder of this response and in the

responses to comments in section 8.2, are discussed in the memorandum “Explanation of Options

for Re-evaluating the Storage Tank MACT Floor for the Production of Pesticide Active

Ingredients NESHAP,” (Docket A-95-20, Docket Item No. IV-B-2).

The proposed approach to developing the MACT floor for storage vessels was

significantly different than the approach used to develop the floor for other rules (e.g., the HON,

polymers & resins, and pharmaceuticals). Since proposal, EPA has reevaluated the revised data

base and determined that an approach consistent with that used for the other rules is feasible and

appropriate for this rule. One of the commenters also recommended that the floor include vapor

pressure cutoffs as in other rules. As a result, EPA decided to revise the MACT floor. The

revised approach established vapor pressure cutoffs at the same storage vessel capacity cutoffs

and control efficiency cutoffs as were used in the previous rules. Specifically, the approach

examined storage vessel cutoffs at 38 cubic meters (m ), 75 m , and 151 m . (In English units, 3 3 3

these capacities correspond with 10,000 gallons [gal], 20,000 gal, and 40,000 gal, respectively,

and the data base includes at least one storage vessel at each of these sizes.) Within these size

ranges, the vapor pressure cutoff at which the majority of storage vessels were controlled to

95 percent or more was determined; the 95 percent level is consistent with the efficiency of

floating roofs, which are the most cost-effective controls.

Under the revised approach, at liquid vapor pressures of 3.45 kPa and higher, the median

control efficiency was found to be at least 95 percent in both the 75 m and larger range and the 3

151 m and larger range; at all vapor pressures, the majority of storage vessels with capacities 3

smaller than 75 m were found to be uncontrolled. The vapor pressure of 3.45 kPa is the vapor 3

pressure of toluene, which is the predominant HAP in the industry and the most common organic

HAP stored in storage vessels. Therefore, the revised MACT floor for storage vessels at existing

sources was determined to be 95 percent control for storage vessels with a capacity greater than

or equal to 75 m that store material with a vapor pressure greater than or equal to 3.45 kPa. In 3

addition, the MACT floor was determined to be no control for all storage vessels with a capacity

less than 75 m .

3
8-3

The MACT floor for storage vessels at new sources is based on the best controlled

storage vessel. As discussed above, the best level of control for storage vessels is considered to

be 95 percent. The capacity of the smallest vessel controlled to 95 percent was determined to be

40 m , and the vapor pressure of the compound stored in this vessel was 16.5 kPa. The MACT 3

floor for new sources must be at least as stringent as the floor for existing sources. Therefore, the

MACT floor for new sources is 95 percent control for storage vessels with (1) a capacity of 40

m or greater that store material with a vapor pressure of 16.5 kPa or greater and (2) a capacity of 3

75 m or greater that store material with a vapor pressure of 3.45 kPa or greater. 3

8.2 STORAGE VESSEL STANDARD

Status at proposal: Under the proposed rule, one regulatory alternative more stringent

than the floor was developed. The regulatory alternative would require 95 percent control of

storage vessels with capacity of 75 m or greater that have uncontrolled emissions of 108 kg/yr or 3

greater. Storage vessels smaller than 75 m (and greater than 38 m ) that have uncontrolled 3 3

emissions of 108 kg/yr or greater would require control to the floor level (41 percent). This

regulatory alternative was determined to be cost effective. Therefore, the proposed standard for

storage vessels at existing sources was established at 95 percent control for vessels with a

capacity greater than or equal to 75 m that have uncontrolled emissions greater than or equal to 3

108 kg/yr.

No regulatory alternatives more stringent than the MACT floor were developed for

storage vessels at new sources. Therefore, the proposed standard for storage vessels at new

sources was determined to be 98 percent control efficiency for storage vessels with a capacity of

26 m or greater with uncontrolled emissions of at least 0.45 kg/yr. 3

8.2.1 Applicability Cutoffs

Comment 1: Several commenters (IV-D-16, IV-D-21, IV-D-22, IV-D-27, and IV-D-29)

requested that EPA increase the lower emission cutoff for existing and new storage vessels. 

Most of the commenters recommended increasing it to at least 500 lb/yr; this level corresponds to

the level in the Batch Processes ACT document for which manifolding to an existing control

device was shown to be cost effective. Commenter IV-D-27 suggested adding an exemption in

§ 63.1360(d)(4) for such vessels. Several of the commenters also noted that combustion would
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be the only feasible means of controlling HAP emissions of only 0.45 kg/yr, and that secondary

emissions would increase significantly as a result.

Response: The Agency has determined that including the higher cutoff suggested by the

commenter would have been less stringent than the cutoff prescribed by the MACT floor. The

emission cutoffs mentioned by the commenters are not supported by the storage vessel data base. 

As discussed in the response to the comment in section 8.1, EPA has revised the MACT

floor since proposal. This revised MACT floor uses storage vessel capacity and the vapor

pressure of stored material as the parameters for determining applicability for storage vessels,

and no uncontrolled emissions cutoff is included in the floor. The Agency expects that

implementing standards based on this format will be considerably easier than implementing the

proposed standards, because no ongoing emission tracking will be required to demonstrate

compliance with a cutoff for the standard. Use of these parameters is consistent with

requirements for storage vessels in other rules.

Comment 2: Commenters IV-D-16 and IV-D-27 stated that the minimum applicability

size cutoff for existing Group 1 storage vessels should be changed to correlate with the NSPS

subpart Kb size cutoff to simplify compliance. The commenters stated that the cutoff for storage

vessels at existing sources would change from 38 m to 40 m . In addition, the commenters 3 3

pointed out that the 38 m cutoff is below the smallest controlled to the median control 3

efficiency in the study (i.e., 39 m ). 3

Response: For the final rule, EPA based the standards for new and existing sources on

the MACT floor because the cost to go beyond the floor was determined to be unreasonable. As

a result of the changes to the database discussed in the response to the comment in section 8.1,

the capacity cutoffs in the final rule are higher than the cutoffs suggested by the commenters. For

existing sources, the cutoff is 75 m instead of the 40 m suggested by the commenters. For new 3 3

sources, the cutoff is 40 m instead of the 39 m suggested by the commenters. 3 3

8.2.2 Control Level of the Standard

Comment: Commenter IV-D-27 requested that EPA keep the existing source standard for

storage vessels with capacities greater than 75 m the same as that for smaller storage vessels, 3
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unless floating roof technology is already in-place. The commenter asserted that the EPA’s

“beyond the floor” standard of 95 percent organic HAP control for existing “large” storage

vessels is not justified for storage vessels that were not already equipped with floating roof

technology. The commenter stated that EPA’s assumption that any existing vessel larger than

75 m can be cost-effectively retrofitted with a floating roof is unrealistic. 3

Response: For the proposed rule, the MACT floor was based on a control efficiency of

41 percent. As discussed in the response to the comment in section 8.1, the revised MACT floor

is based on 95 percent control. The final standards also are based on a control of 95 percent

because the cost to control to a higher level was determined to be unreasonable. Now that both

the MACT floor and the standard are based on the same control efficiency, the commenter’s

concern about going beyond the floor is no longer relevant. However, EPA wishes to emphasize

that the costs for the proposed standard were determined to be reasonable. The costs estimated at

proposal reflect the costs for retrofitting an existing fixed roof vessel with an internal floating

roof (IFR). These costs were based on equations developed from vendor information on the cost

of installing a new aluminum, noncontact IFR with a vapor-mounted primary seal and a

secondary seal; this cost estimate included retrofit costs for modifying the vessel, including any

corrections to vessel shell deformations or obstructions, any special structural modifications, and

cutting vents or openings if necessary. The estimated costs also included the costs to empty,

clean, and degas the vessel prior to retrofit.

8.2.3 Format of the Standard

Comment: Commenters IV-D-21, IV-D-28, and IV-D-29 stated that EPA should allow

floating roofs as a control option for storage vessels at new sources. Commenters IV-D-21 and

IV-D-29 stated that it is possible to reduce emissions of some HAP by 98 percent using a floating

roof, with the efficiency calculated using TANKS3.

Response: As discussed above, the control level for storage vessels at new sources is 95

percent under the final rule. Floating roof technology is allowed to meet this limit, just as it is for

existing sources. 
8-6

8.3 COMPLIANCE AVERAGING PERIOD

Comment: Commenter IV-D-27 requested that the storage vessel standards be on an

annual average basis to reflect the data used in developing the standards (the commenter included

data for the median controlled vessel, which is controlled with a condenser; the data show the

variation in emissions and control efficiency throughout the year for this vessel).

Response: The EPA does not agree with the commenter’s assertion that the data used to

develop the MACT floor reflect only an annual compliance period. All of the storage vessels in

the revised MACT floor analysis (see section 8.1) that are controlled to at least 95 percent are

controlled with technologies (i.e., combustion devices) that achieve their control efficiency at all

times (i.e., as averaged over a period as short as the 3-hour period of a performance test). The

storage vessel that is controlled with a condenser is not part of the majority controlled to at least

95 percent in the revised MACT floor analysis. Therefore, the final rule retains the requirement

to demonstrate compliance with the percent reduction or outlet concentration limit for an add-on

control device on a daily basis. Alternatively, the owner or operator may install a floating roof,

which must be inspected annually and as otherwise specified in § 63.120 of the HON.

8.4 STORAGE VESSEL DEFINITION

Comment 1: Commenters IV-D-21 and IV-D-29 recommended that EPA adopt the

complete SOCMI MACT storage vessel definition set in the PAI NESHAP. 

Response: The definition for storage vessels for the PAI industry is similar to the

definition used in the HON. Additional language contained in the HON definition for storage

vessels includes a vessel “. . . that has been assigned . . . to a chemical manufacturing process

unit that is subject to this subpart.” This language regarding the assignment of storage vessels to

the source category or a PAI process unit that is subject to subpart MMM has been added to the

definition in the final rule. The only remaining difference between the two definitions is that the

HON excludes only bottoms receivers and surge control vessels, and the PAI draft rule excludes

all process vessels. Under the PAI rule, bottoms receivers and surge control vessels are process

vessels. Thus, they are not regulated as storage vessels under either rule. The exclusion of

process vessels has been retained in the definition for storage vessels. The response to comments
8-7

in section 7.7 of this document provides rationale for regulating bottoms receivers and surge

control vessels as process vessels.

Comment 2: One commenter (IV-D-27) suggested that EPA add two exclusions to the

storage vessel definition: (1) vessels regulated under 40 CFR 260 through 270 RCRA

provisions, and (2) other waste vessels (nonwastewater). Because EPA’s data base only contains

vessels used for storing raw materials and products, other types of vessels should be excluded.

Response: Storage vessels containing waste materials were not intended to be included

under the storage vessel definition. The PAI data base includes only those storage vessels that

contain raw materials, solvent, or product. Therefore, an exclusion for nonwastewater waste

vessels has been added to the definition of storage vessels in the final rule. This exclusion

includes vessels subject to 40 CFR parts 260 through 270.

8.5 OVERLAP WITH OTHER STANDARDS

Comment: Commenter IV-D-27 requested that EPA specifically state that regulated

emissions from pesticide manufacturing storage vessels that are routed to RCRA incinerators are

deemed to comply with the standards of this rule with no additional performance testing,

monitoring, recordkeeping or reporting requirements.

Response: The proposed rule exempted an owner or operator from performance test

requirements for RCRA control devices, and this provision was retained in the final rule. In

addition, the final rule exempts the owner or operator from monitoring, recordkeeping, and

reporting provisions when emissions are routed to a RCRA control device because these RCRA

provisions also are at least as stringent as the provisions in the final rule.

8.6 CLARIFICATIONS

Comment 1: Commenter IV-D-28 suggested that EPA change every use of “control

device” to “control device(s).” The commenter stated that the proposed rule appears to require

that only a single control device be used to control emissions from a storage vessel, however,

combinations of control devices should be allowed, as appears to be the case for other streams.

Response: The Agency agrees with the comment regarding the use of multiple control

devices on a single process; it was not EPA’s intention to limit the control scenario implemented
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by a facility. Either a single control device or a series of control devices is acceptable as long as

the overall control efficiency specified by the regulation is achieved. The term “control

device(s)” has been added to the pesticide regulation in place of “control device” to make it clear

that use of multiple control devices is acceptable.

Comment 2: Commenters IV-D-21 and IV-D-29 point out that § 63.1362(c)(1)(ii) refers

to control devices “designed to reduce emissions of organic HAP by greater than 41 percent but

less than 95 percent.” The commenters assert that including the words “95 percent” is not

necessary and makes this statement confusing. The commenters recommend that the words “but

less than 95 percent” be removed to help clarify this section.

Response: This provision in the proposed rule referred to storage vessels that are already

controlled at least to the level of the floor, but do not exceed the level of the standard. Because

the standard in the final rule is equivalent to the floor, this provision is no longer needed and has

been deleted.

Comment 3: One commenter (IV-D-16) pointed out that in both the definitions of

Group 1 Storage Vessel (§ 63.1361) and the standard (§ 63.1362), the conversion from metric

units to English units are rounded off. The commenter requests that EPA provide a more precise

conversion to English units.

Response: In an effort to reduce confusion over the conversion from English to metric

units (or vice versa), only metric units have been included in the final rule. This is consistent

with the approach used in the HON.
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9.0 STANDARDS FOR EQUIPMENT LEAKS

9.1 LEVEL OF THE STANDARD

Comment: The MACT floor for equipment leaks was determined to be no control, and

the proposed standard was based on a more stringent regulatory alternative that consisted of

implementation of the leak detection and repair (LDAR) program from the HON. Six

commenters (IV-D-14, IV-D-16, IV-D-20, IV-D-21, IV-D-27, and IV-D-29) stated that the

standard should not be based on the LDAR program from the HON because their analyses show

it is not cost effective. Several commenters provided data contradicting both the emission rates

and costs used in EPA’s cost analysis.

All six commenters asserted that initial equipment leak frequencies and thus the actual

emissions rates are lower than EPA estimated using the SOCMI average emission factors. 

According to commenter IV-D-16, recent screening data obtained to demonstrate compliance

with the HON, P&R IV, and State programs (from 7 companies and 21 processes, not necessarily

PAI) show current industry maintenance, design, and materials selection result in far lower leak

rates and emissions than EPA assumed; commenter IV-D-21 made a similar summary statement. 

Commenter IV-D-16 provided a tabular summary of leak rates for more than 100,000 connectors,

64,000 valves, and 1,400 pumps. Estimated emissions based on these data are approximately

6 percent of the level used in the EPA analysis. Commenter IV-D-27 also stated that leak rates

are typically less than 5 percent of the value obtained using the SOCMI average emission factors. 

Commenter IV-D-16 noted that this level is comparable to the controlled level estimated by EPA,

and concluded that any additional reductions achieved by implementing the standard would be

extremely small. Commenters IV-D-16 and IV-D-27 believe EPA’s assumption that the fluid in
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contact with each component is 100 percent HAP is overly conservative; commenter IV-D-27

suggested 50 percent would be a better value.

Commenters IV-D-14, IV-D-16, and IV-D-27 asserted that the costs used in the EPA

analysis were underestimated. Commenter IV-D-27 provided the following specific examples

based on a quote the commenter obtained from Team Industrial Services to conduct an LDAR

program: (1) initial and annual monitoring costs should be at least $4.50/component and

$2.95/component, respectively, instead of $2.50/component and $2.00/component; and (2) labor

costs to repair components should be at least $30.00/hour, not $22.50/hour. Commenter IV-D-27

also noted that the lower emissions estimated by the commenters results in a smaller product

recovery credit than EPA estimated.

Based on the available information, commenters IV-D-14, IV-D-16, and IV-D-27

estimated cost-effectiveness values that are much higher than EPA’s estimate. Based on

unspecified data and assumptions, commenter IV-D-14 estimated the cost effectiveness to be

more than $35,000/Mg for a facility with 215 pumps, 4,460 valves, and more than

16,000 connectors. Commenter IV-D-27 estimated the cost effectiveness for the nationwide

population of components in EPA’s analysis to be more than $64,000/Mg; this estimate was

based on the revised monitoring and labor costs described above, assuming fluid in contact with

the components contains 50 percent HAP, and assuming that the LDAR program would achieve

the same percentage emission reductions that were used in the EPA analysis. 

Commenter IV-D-16 calculated a cost effectiveness of $78,000/Mg for the nationwide

population of components in EPA’s analysis; this estimate was based on the costs from EPA’s

analysis, assuming the LDAR program would achieve a 10 percent reduction in emissions from

the lower baseline described above.

Commenters IV-D-16 and IV-D-20 recommended that EPA consider setting a standard

based on a sensory (visual, olfactory, audible) LDAR program or other alternatives that are under

consideration for other rules (i.e., for formulation processes covered by the MON or the draft

Generic MACT standards, part 63 subparts TT and UU).

Response: In recent regulatory development efforts involving similar industries, the EPA

has generally found equipment leaks to be a significant source of emissions. The EPA’s
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approach has been to require industries to identify leaks and fix them as soon as possible. The

EPA is sensitive to the recordkeeping burden associated with an LDAR program for this industry

and has strived to minimize the number of activities that have to be conducted and documented

while still requiring sources to identify and eliminate equipment leaks. Relative to earlier rules,

the Agency developed the HON to focus most of the recordkeeping and reporting burden on

those processes and types of equipment that have the most significant leaks, in terms of HAP

emissions. Since the development of the HON, the Agency has proposed the consolidated air

rule (CAR) that is designed to minimize the reporting and recordkeeping burden even further

(see 63 FR 57748). The EPA believes that, in addition to consolidating many LDAR programs,

the CAR addresses many concerns regarding the burden placed on industry to implement LDAR

programs with little environmental benefit. The proposed CAR is specifically focused on

identifying and fixing leaking components, and leaves out many of the recordkeeping

requirements that are focused on nonleakers. For example, the proposed CAR includes options

for identifying groups of equipment, such as valves, that are located within an area or length of

pipe without individually listing each component. The proposed CAR also allows much less

frequent monitoring of components, depending on leak rates identified during an initial survey. 

If less than 0.25 percent of connectors are found to be leaking, monitoring is only required every

8 years (however, at least 50 percent of the connectors must be monitored during the first 4 years,

and the remainder must be monitored within the next 4 years). For valves, the required

monitoring frequency can be as low as every 2 years, if the percentage of leakers for a given

group is less than 0.25 percent.

In general, commenters contend that EPA has overstated the reductions achieved by the

LDAR program and understated the costs in estimating cost effectiveness. In response to

commenter concerns, EPA reviewed the original analysis and also calculated the cost

effectiveness of a revised LDAR program based on the requirements of the proposed CAR. The

revised analysis used the data supplied by the commenters; the EPA also combined recently

obtained initial leak rate data for components in pharmaceutical processes with the data provided

by commenters. The EPA does not consider the emission estimates in the original analysis to be

invalid. However, for the revised analysis, EPA used the leak rate data provided by the

commenters and other recently obtained data to determine a lower bound on the baseline
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emissions (and a corresponding upper bound on cost effectiveness for a given set of assumptions

regarding subsequent leak frequencies and the number of monitoring instruments that are

needed). The remainder of this response summarizes the procedures and results of the revised

analysis. This summary includes a description of models used in the analysis, procedures to

calculate emissions, specific aspects of the costing methodology, and the estimated cost

effectiveness. Details of the analysis are documented in reference number 1 (Docket

No. A-95-20, Docket Item No. IV-B-3). As a result of this analysis, the standards for equipment

leaks have been changed since proposal; the requirements in the final rule are consistent with the

proposed CAR requirements rather than the subpart H requirements.

Models. Batch and continuous model processes were developed for the original analysis

and these models were also used in the revised analysis. The batch process consisted of 65 gas

valves, 340 liquid valves, 14 pumps, and 1,100 connectors. The continuous process consisted of

240 gas valves, 1,100 liquid valves, 33 pumps, and 1,500 connectors. For this analysis, all

valves were considered to be liquid valves because the commenters provided leak rate data only

for “valves.” Components in the batch process were assumed to be in service for 2,800 hr/yr, and

components in the continuous process were assumed to be in service for 5,000 hr/yr.

Emissions Estimates. Uncontrolled emissions for the model processes were estimated

based on initial leak rate data. The EPA started with the initial leak rate data provided by the

commenters. Most of these data were from facilities in the SOCMI or polymers and resins

industry. The EPA also combined recently obtained initial leak rate data for components in

pharmaceuticals processes with the data provided by the commenters. These data were combined

because EPA believes pharmaceuticals processes are at least as representative of PAI processes

as are SOCMI or polymers and resins processes due to the prevalence of batch processing,

similar process equipment, and similar HAP in the pharmaceutical and PAI industries. 

Combining the two data sets approximately doubled the amount of available data to 200,000

connectors, 87,000 valves, and 2,600 pumps. All of the leak rates for a particular type of

component in the data base were summed. To estimate average leak rates, each of these overall

leak rates was divided by the total number of that type of component in the data base. 
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Uncontrolled annual emissions for the two model processes were estimated by multiplying these

average leak rates by both the number of components and the operating hours for the models.

Controlled emissions for the two model processes were based on several assumptions

about subsequent leak rates because leak rate data are not available. For valves and connectors,

the leak frequency occurrence rates after implementation of LDAR were assumed to be equal to

the performance levels required in the proposed CAR (i.e., 0.25 percent). The EPA also assumed

that repairs are 100 percent effective, and that there are no recurrences of leaks. These

assumptions are similar to those in the HON, except that the occurrence levels are lower than

those assumed in the HON analysis. These appear to be reasonable assumptions given the fact

that the initial leak frequencies for valves and connectors were in some cases lower than the

specified performance level. For pumps, the CAR does not specify a performance level. 

Therefore, it was assumed that the leak occurrence rate after implementation of the LDAR

program is equal to 50 percent of the initial leak frequency. This assumption appears reasonable

based on the leak frequency reductions that have been achieved by other LDAR programs. The

initial leak frequency for pumps was estimated to be 7.44 percent by using the estimated

uncontrolled average leak rate for pumps (as estimated above) in the average leak rate (ALR)

equation for a leak definition of 1,000 ppmv. (The ALR equations are presented on page 5-46 of

the EPA document entitled “Protocol for Equipment Leak Emission Estimates,”

EPA-453/R-95-017, November 1995.) The occurrence rate for pumps, therefore, was assumed to

be 3.72 percent. Controlled average leak rates were estimated using one-half of the occurrence

rates in the appropriate ALR equations (i.e., equations for leak definitions of 500 ppmv for

valves and connectors, and 1,000 ppmv for pumps). One-half of the occurrence rate is assumed

to be the average leak frequency over the monitoring cycle. Controlled annual emissions for the

two model processes were estimated by multiplying these average leak rates by both the number

of components and the operating hours for the models.

Unlike the original analysis, the revised analysis does not depend on the assumption that

components are in 100 percent HAP service. The leak-rate methodology used in the revised

analysis estimates the amount of organic compounds (VOC or HAP) emitted. Thus, the analysis

will overstate the HAP emissions if the leak includes non-HAP VOC. In these situations,
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however, the program will still control the remaining non-HAP VOC, and the cost effectiveness

will reflect the control of both HAP and VOC.

Costing Methodology. In general, the LDAR costs are based on procedures and unit costs

that were used in the analysis for the HON. The approach identifies both initial costs to establish

the monitoring program, recurrent annual costs to monitor and repair leaks, and a credit for

product recovered by reducing leaks. Initial LDAR monitoring and repair costs and the cost of a

monitoring instrument are annualized using a capital recovery factor. Monitoring and repair

costs are assumed to be the same every year. The total annual cost of the LDAR program is the

sum of the annualized initial costs plus the annual monitoring and repair costs minus product

recovery credits.

A review of the costing methodology indicated that costs for the monitoring instrument

needed to be updated, but no changes are warranted in other elements of the methodology. The

original analysis was based on costs for a monitor that is no longer available. Capital costs for a

currently available monitor that is widely used are higher than the capital costs for the original

monitor, but maintenance costs are lower. See reference number 2 (Docket No. A-95-20, Docket

Item Numbers IV-B-6 and IV-B-7). As a result, total annual costs for the new monitoring

instrument are lower. A discussion of other costs in the analysis is provided below.

One commenter stated that initial and annual monitoring costs should be at least

$4.50/component and $2.95/component, respectively, instead of $2.50/component and

$2.00/component. The commenter indicated that the higher values were based on costs typically

charged by contractors who monitor equipment for leaks as a service. Unit monitoring costs in

the EPA analysis are lower because they include only labor costs. When a monitoring contractor

is hired, the cost per component must consider annualized costs of implementing the overall

program, including overhead costs and the costs of purchasing and maintaining a monitoring

instrument. Adding 40 percent to account for overhead costs increases the unit monitoring costs

used by EPA to $3.50/component and $2.80/component. The annual maintenance charge plus

the annualized purchase cost of the monitoring instrument adds another $2.00/component to both

values; this value is likely higher than the cost to a monitoring contractor because it assumes the

monitoring instrument is only fully utilized in the first year (this was not an issue in the original
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analysis because all components were assumed to be monitored the same number of times each

year). The resulting costs of $5.50/component and $4.80/component are higher than the values

quoted by the commenter. Therefore, EPA did not change the monitoring costs for this analysis.

One commenter stated that labor costs to repair components should be at least $30.00/hr,

not $22.50/hr. The actual cost in the EPA analysis is $22.50/hr, multiplied by a factor of 1.4 to

add another 40 percent for administrative and support costs, which yields a value of $31.50/hr. 

Again, this value is comparable to the value quoted by the commenter. Therefore, EPA did not

change the labor cost for this analysis.

The total annual costs (TAC), after accounting for product recovery, were estimated to be

$2,066/yr for the batch model process and $5,226/yr for the continuous model process. The total

capital investment (TCI) is $7,914 for the batch model process and $15,277 for the continuous

model process. The TCI includes both the cost of the monitoring instrument and the cost for the

initial round of monitoring and repair.

Impacts. Nationwide emissions were estimated by scaling the emissions for the model

processes based on the number of batch and continuous processes in the PAI industry. 

Nationwide, there are an estimated 146 batch processes and 43 continuous processes. The

nationwide uncontrolled emissions for equipment components in the PAI industry are estimated

to be 503 Mg/yr, and the nationwide controlled emissions following implementation of the

LDAR program in the CAR are estimated to be 117 Mg/yr; the nationwide emission reduction is

estimated to be 386 Mg/yr.

Nationwide costs to implement an LDAR program for the PAI industry consistent with

the program in the CAR were estimated using two approaches. In the first approach, the

monitoring instrument capital cost and annual maintenance cost were prorated based on the ratio

of the nationwide number of components as characterized by the two model processes to the

number of components that a fully utilized instrument could be used to monitor (i.e., about

9,000 components). The second approach, a more conservative one, assumes one instrument is

needed for every 9,000 components (or fraction thereof) at each facility. Under second approach,

a total of 80 monitoring instruments would be needed (58 for the 58 modeled facilities, and 22
9-8

for the 20 surveyed facilities (some of the surveyed facilities needed two instruments because

they had more than 9,000 components in PAI processes).

The nationwide costs under both approaches were estimated by scaling the unit costs for

the model processes based on the number of batch and continuous processes in the PAI industry. 

As a result, the estimated nationwide TCI and TAC using the first approach are $1.81 million and

$526,000/yr, respectively. Using the second approach, the TCI and TAC increase to

$2.26 million and $692,000/yr, respectively.

Cost Effectiveness. The cost effectiveness associated with implementation of an LDAR

program consistent with the requirements of the proposed CAR using the first costing approach

is estimated to be $1,400/Mg at existing sources ($526,000/386 Mg). The cost effectiveness at

existing sources using the second approach is estimated to be $1,800/Mg ($692,000/386 Mg). 

Both of these values are considered to be reasonable.

9.2 CROSS-REFERENCING THE CONSOLIDATED AIR RULE

Comment: The preamble to the proposed rule states that EPA will consider

cross-referencing the CAR if the CAR is complete before this rule is promulgated. 

Commenter IV-D-28 strongly opposes cross-referencing requirements in the CAR (unless the

CAR requirements are only one option) because the CAR has become more and more

complicated, still contains flaws, and has not been promulgated.

Response: The EPA has decided to incorporate requirements consistent with those of the

proposed CAR into this final rule, as opposed to cross-referencing them. The EPA intends, with

this action, to minimize confusion and reduce the potential for errors and inconsistencies that

could be created by cross referencing.

9.3 REFERENCES

5. Memorandum from B. Shine and K. Schmidtke, MRI, to Project File. October 21, 1998. 

LDAR program cost effectiveness.

6. Memorandum from K. Barnett, EPA:ESD, to Equipment Leaks Costing Project File. 

October 18, 1998. Equipment leaks costing.
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10.0 STANDARDS FOR WASTEWATER

10.1 GENERAL

Comment: Commenter IV-D-20 believes the wastewater provisions should be based on

the proposed pharmaceuticals rule, not the HON, because: (1) both the pharmaceuticals and PAI

manufacturing industries produce biologically active materials and are relatively small in scale

compared to SOCMI facilities (the commenter noted that the surveyed facilities are larger than

the typical manufacturing processes within the PAI industry), (2) the evaluation for the proposed

pharmaceuticals rule was based on more recent emission models and a more thorough assessment

of emissions and control costs, and (3) the HON wastewater requirements are extremely complex

and difficult to understand. Other commenters requested that only specific provisions from the

proposed pharmaceuticals rule be included in this rule, as noted in the comments below.

Response: The EPA disagrees with the commenter’s claim that the proposed

pharmaceuticals wastewater provisions are more appropriate than the provisions in the HON for

the PAI source category. First, although the scale of PAI operations typically is closer to

pharmaceuticals than to SOCMI, the applicability cutoffs in both the HON and pharmaceuticals

regulations are comparable. Second, the analysis for the pharmaceuticals proposed standard was

not better, it was just different. For example, the pharmaceuticals analysis was based on the use

of methanol as a model compound because of the prevalence of that compound in the

pharmaceuticals industry, but the HON analysis modeled each HAP. Comparisons of specific

aspects of the provisions in the two rules are discussed in many of the responses in the remainder

of this chapter.

10.2 AFFECTED WASTEWATER
10-2

Comment 1: Several commenters (IV-D-14, IV-D-21, IV-D-28, and IV-D-29) stated that

maintenance wastewater streams should either be excluded from the regulation or subject to the

same requirements as in § 63.105(b)(2) of the HON. All of the commenters cited the variability

and unpredictable nature of maintenance wastewater streams (which makes it difficult to

determine whether a stream is Group 1 or Group 2) and the low potential for substantial

emissions (because such streams are typically due to rinsing or flushing equipment) as reasons to

regulate maintenance wastewater streams differently. Commenter IV-D-28 added that

maintenance wastewater streams cannot be controlled like process wastewater streams. For

example, the commenter explained that trying to pump the small amount of water generated

when bleed lines or pumps are drained would cause equipment problems if there was not enough

flow to keep material running through the pump itself. Commenter IV-D-28 also stated that the

cost to comply with conveyance requirements would be enormous, especially if an enclosed

system has to be installed for every piece of equipment because someday a maintenance

wastewater stream might be generated there.

Response: The EPA considered the above comments and is persuaded by the

commenters’ arguments that the variability of maintenance activities makes characterization of

these wastewaters difficult, and that there is fairly low potential for substantial emissions for

most of these wastewater streams. However, EPA has no data on typical quantities of

maintenance wastewater streams generated, or the characteristics of these wastewater streams. 

Therefore, EPA’s approach, in resolving this issue, was to specify characteristics of maintenance

wastewater streams that have significant emission potential. The EPA also sought to minimize

the burden of characterization of all maintenance wastewater streams. Based on this approach,

EPA evaluated three possible options for regulating maintenance wastewater streams. The first

option was to adopt the same requirements as in § 63.105 of the HON, which is the option

suggested by the commenters. The EPA believes that maintenance wastewater streams may

warrant a different treatment in this industry than what was done under the HON because the PAI

industry is expected to generate process wastewater streams in discrete batches, due to the batch

nature of the industry. These process wastewater streams are expected to have properties similar

to those for maintenance wastewater streams in terms of the quantities generated, the frequency

of generation, and the options for management, suppression and treatment. Therefore, for
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streams with significant emissions potential, whether generated because of maintenance activities

or by the process operations, EPA believes that proper management and treatment is warranted. 

The second option evaluated was to require the same management and treatment for both

maintenance and process wastewater streams, as in the proposed rule. Under this option, the

applicability thresholds are the same as in the HON for both types of streams. However, because

information on maintenance wastewater streams is unavailable, it is not clear how many such

streams would be subject to management and treatment requirements. For example, one extreme

is that industry would be required to characterize numerous maintenance wastewater streams

with no environmental benefit. Conversely, it is possible that many streams with low flow rates

and low emission potential would meet the Group 1 applicability thresholds of 10,000 ppmw at

any flow rate. Another concern with this option is the extent of dedicated maintenance

wastewater conveyance systems that will need to meet emission suppression requirements on the

chance that a Group 1 maintenance wastewater stream might be discharged in the processing area

served by that part of the conveyance system.

Finally, the third option considered and incorporated into the final rule is a modification

of option 2 that does not require characterization, suppression, and treatment of small

maintenance wastewater streams with low emission potential. The HON includes two thresholds

for triggering Group 1 applicability: the first, which has already been discussed, captures any

streams with greater than 10,000 ppmw HAP load and does not consider emissions potential; the

second applicability threshold, however, considers emission potential by adding a quantity

(greater than 10 liters per minute [L/min]) in addition to the HAP concentration (1,000 ppmw

HAP). When converted to HAP load, the second applicability threshold is equivalent to

approximately 5.3 Mg of HAP. This load was used as the applicability threshold in the definition

of maintenance wastewater in the final rule. The final rule also specifies that the maintenance

wastewater definition applies to individual discharge events, not the sum of all events occurring

from a single POD over the course of a year. By defining maintenance wastewater streams in

this manner, only the largest, most significant maintenance wastewater streams would be subject

to suppression and treatment. These large streams should be easier to identify and may occur

only at certain POD’s. The definition of Group 1 wastewater streams also includes maintenance
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wastewater streams with this same load; thus, there are no Group 2 maintenance wastewater

streams, and there is no burden to characterize and track any maintenance wastewater streams

other than Group 1 streams. 

It is conceivable that there are no maintenance wastewater streams with characteristics

approaching this definition in the industry. However, because EPA has no data on the quantities

or characteristics of these maintenance wastewater streams, EPA believes the best approach is to

define a threshold of concern rather than to exempt from suppression and treatment all

maintenance wastewater streams.

The EPA considered the example brought up by the commenters of needing to drain

maintenance wastewater streams onto diked floor areas and sumps prior to sending to enclosed

drains. The commenters argue that it would be unreasonable to build enclosed conveyance

systems for all maintenance wastewater streams that require control. However, EPA believes

that those few maintenance wastewater streams that could trigger Group 1 applicability would be

routed to a process or chemical sewer to begin with, regardless of whether they were considered

affected streams for purposes of this MACT standard, and believes that most facilities are

capable of routing wastewaters through temporary flexible hoses to a conveyance system that

would serve a chemical or process sewer especially for these situations.

Comment 2: Because the MACT floor for wastewater at existing sources is no control,

commenter IV-D-16 recommended that EPA exclude from control requirements those streams

that have low emission potential. Therefore, the commenter recommended that EPA establish an

alternative Group 1 threshold for soluble HAP with low vapor pressures, similar to the threshold

in the proposed pharmaceuticals rule. Another commenter (IV-D-27) also requested that EPA

add alternative Group 1 thresholds based on differences in the volatility of HAP compounds, like

those for partially soluble and soluble HAP compounds in the proposed pharmaceuticals rule. A

third commenter (IV-D-28) supports the proposed approach to classify process wastewater (but,

as noted above, not maintenance wastewater streams) as Group 1 or Group 2, and require control

only for wastewater classified as Group 1.

Response: Under the proposed rule, streams with low emission potential were excluded

by the 1,000 ppmw and 10 L/min cutoffs. In addition, a facility would not be required to control
10-5

any wastewater streams if the total load of Table 9 compounds in Group 1 wastewater (untreated

or treated to levels less than required by the standards) from the “total source” (for the final rule,

this term is defined to mean the affected source) is less than 1 Mg/yr. The EPA determined that,

on average, treatment of streams with concentrations and flows that exceed the cutoffs was cost

effective. If a stream contains compounds with low Henry’s law constants, the “low potential”

for emissions is accounted for by requiring less stringent control based on low Fr values. This

approach also is consistent with the HON, which should facilitate compliance for many facilities,

and is consistent with one commenter’s request that provisions be like the HON wherever

possible. Thus, the final rule does not include alternative Group 1 thresholds.

10.3 TREATMENT OPTIONS FOR DISCHARGES TO POTW’s

Comment 1: Three commenters (IV-D-16, IV-D-20, and IV-D-27) requested that the

enhanced biological treatment option in the proposed pharmaceuticals MACT standard be

included in this rule (i.e., for wastewater that contains soluble HAP and less than 50 ppmw of

partially soluble HAP) for discharges to a POTW. According to commenter IV-D-20, the HON

provisions essentially preclude discharge to POTW’s because POTW’s could not reasonably be

expected to understand, implement, and certify compliance with this regulation. Furthermore,

the commenter stated that the detailed analysis performed for the proposed pharmaceuticals rule

indicated that air emissions for certain wastewater streams would be negligible; thus, there is no

need to essentially ban discharge to POTW’s.

Response: Except for minor differences in applicability cutoffs, one of the treatment

options in the HON (and thus in the proposed rule) is similar to the enhanced biotreatment option

under the proposed pharmaceuticals rule. Both the HON and the proposed pharmaceuticals rule

regulate two groups of HAP compounds in wastewater. For the HON, the groups are called “list

1” and “list 2” compounds. For the proposed pharmaceuticals standard, they are called “partially

soluble HAP” and “soluble HAP.” All 52 of the compounds on list 2 are also classified as

partially soluble HAP. List 1 contains all 14 soluble HAP as well as the 10 remaining partially

soluble HAP. (Note that for the final pharmaceuticals rule, epichlorohydrin has been moved

from the solubles list to the partially solubles list.) Under the HON, an owner or operator is

exempt from the performance test requirement if (1) wastewater is treated in an enhanced
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biological treatment process and (2) compounds on list 1 comprise at least 99 percent by weight

of the HAP compounds (list 1 plus list 2) in the wastewater. Under the proposed

pharmaceuticals standard, an owner or operator would be exempt from the performance test

requirement if wastewater containing soluble HAP and less than 50 ppmw of partially soluble

HAP is treated in an enhanced biological treatment unit, and the owner or operator demonstrates

that less than 5 percent of the soluble HAP is emitted from the municipal sewer system. The

definition of an enhanced biotreatment unit is also the same under both rules, and waste

treatment units that qualify as enhanced biotreatment units are subject to the same compliance

requirements under both rules. Therefore, EPA disagrees with the commenter’s assertion that the

treatment provisions in the proposed rule reduce the burden on POTW’s, and EPA has not

revised the treatment provisions for today’s final rule.

Comment 2: Commenter IV-D-16 cited the results of a study conducted by

Pharmaceutical Research and Manufacturers of America (PhRMA) (and discussed in detail in

PhRMA’s comments on the proposed pharmaceuticals rule) showing that streams discharged to

POTW’s have the potential for significant emissions only from “totally open” collection and

municipal sewer systems. Therefore, if the collection and municipal sewer system is totally

open, the commenter recommended adding a provision that would allow an owner or operator to

use the enhanced biotreatment option only if the owner or operator demonstrates that less than 5

percent of the soluble HAP is emitted from the system (and would not impose this requirement if

the system is not “totally open”).

Response: Under the proposed rule, an offsite facility that treats wastewater would be

required to comply with the same requirements as an affected source, including the emission

suppression requirements from the collection system. The EPA has reexamined municipal sewer

systems and determined that the primary potential for emissions from the collection system is

from the headworks at the POTW. Thus, the final rule specifies that either the waste

management units up to the activated sludge unit must be covered, or the owner or operator must

demonstrate that less than 5 percent of the total list 1 HAP is emitted from these units.

10.4 STANDARDS FOR NEW SOURCES
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Comment: Several commenters (IV-D-16, IV-D-21, IV-D-27, IV-D-28, and IV-D-29)

consider the proposed wastewater standards for new sources with HAP loading greater than

2,100 Mg/yr to be too restrictive. Commenter IV-D-27 believes only Group 1 wastewater, not all

wastewater, should be subject to the standards. The commenter claims that requiring control of

all wastewater will result in negligible additional environmental benefits, but would likely cause

greater secondary air and resource impacts (e.g., from fuel usage and emissions of combustion

products).

All five commenters requested that additional treatment options be allowed. 

Commenter IV-D-28 requested that EPA add a treatment option that allows an owner or operator

to reduce the mass flow rate by the Fr values; the commenter stated that a 99 percent reduction

might be achievable for an individual facility with a certain combination of HAP, but it would

not be achievable by all facilities. Commenters IV-D-16, IV-D-21, IV-D-27, and IV-D-29

recommended adding at least an enhanced biotreatment option. Commenter IV-D-27 believes all

of the treatment options for existing sources should be allowed for new sources. 

Commenters IV-D-16, IV-D-21, IV-D-27, and IV-D-29 requested the additional options because

they believe that limiting treatment options significantly impacts compliance flexibility with

little, or no, environmental benefit. For example, commenter IV-D-27 realizes that a steam

stripper would not meet the standard for compounds that have Fr values less than 0.99, but

believes that because the remaining HAP in the treated streams are less volatile, they would have

negligible air impacts. Several commenters (IV-D-16, IV-D-21, and IV-D-29) stated that EPA

had agreed during the development of revised wastewater provisions for the HON that the

various treatment options under the HON are equivalent from an air emissions standpoint (e.g.,

95 percent reduction in a biological treatment unit is equivalent to 99 percent reduction in a

non-biological treatment unit).

Response: According to the Act, the MACT floor for new sources is to be based on the

emission control that is achieved by the best controlled similar source. In the PAI production

industry, the best controlled source is achieving 99 percent control. This source also is treating

all of its wastewater from PAI processes, the HAP load in this wastewater is 2,100 Mg/yr, and

this wastewater contains a mixture of compounds with a range of Henry’s law constants. Thus,
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the proposed MACT floor for new sources with a HAP load exceeding 2,100 Mg/yr consisted of

the requirements to treat all wastewater and to achieve a 99 percent reduction in the HAP content

in the wastewater; for new sources with lower HAP loadings, the MACT floor is no control, as

for existing sources. The EPA continues to stress that the proposed MACT floor is consistent

with the Act, and it is retained in the final rule. 

If a facility has a HAP load that exceeds the cutoff, the enhanced biotreatment option

(i.e., the option that exempts an owner or operator from initial compliance demonstrations) is not

allowed because the EPA does not have information showing that enhanced biotreatment units

achieve 99 percent removal for mixtures of compounds with low Fr values. Otherwise, the final

rule allows any treatment option (including enhanced biotreatment) for such affected sources,

provided the owner or operator demonstrates that it achieves 99 percent removal of all HAP in

the wastewater. The EPA also points out that the requirement to achieve 99 percent removals

applies only to facilities that have extremely high HAP loads and thus, high potential for

emissions. Few new sources are likely to exceed the applicability cutoffs for the MACT floor

because 2,100 Mg/yr was more than three times higher than the load at any other surveyed

facility.

Finally, the commenter’s statement about the equivalence of treatment options needs

clarification. Under the HON, the 95 percent option for biological treatment units requires that

the reduction be achieved from all wastewater sent to the treatment unit, not just the Group 1

wastewater. The 95 percent reduction also applies to all Table 9 compounds (in subpart G) in the

wastewater, not just compounds with high Fr values. Thus, on average, this option is considered

equivalent to other treatment options in the HON. This option is not considered equivalent to the

99 percent option for new sources described above because the 99 percent reduction is required

for all wastewater and all compounds.

10.5 OVERLAP WITH OTHER REGULATIONS

Comment 1: Commenter IV-D-27 believes the rule should state that routing regulated

wastewater (and associated emissions and residuals) to a RCRA incinerator constitutes

compliance with the standards, and no additional performance testing, monitoring,

recordkeeping, or reporting is required.
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Response: The proposed rule cross-referenced § 63.138(h) of the HON, which specifies

that RCRA units used to treat wastewater streams and residuals are exempt from design

evaluation or performance test requirements, monitoring requirements, and associated

recordkeeping and reporting requirements. This cross-reference is retained in the final rule.

Comment 2: Commenter IV-D-28 suggested adding a paragraph to § 63.1362(d) to avoid

an overlap between this rule and subpart DD (Off-Site Waste and Recovery Operations). The

commenter noted that all organic HAP-containing wastes that are sent to an offsite facility for

treatment become subject to subpart DD, unless stated otherwise in subpart DD. Subpart DD

contains an exemption for wastewater from a HON facility. However, it does not contain an

exemption for wastewater from other facilities subject to MACT standards, even those, like the

proposed rule, that require compliance with the wastewater provisions in the HON. Therefore,

the additional provision recommended by the commenter would stipulate that an offsite facility is

not subject to the requirements of subpart DD for wastewater streams and residuals received

from an affected source.

Response: The PAI rule cannot include a provision that modifies the requirements of

another rule. However, EPA will consider amending subpart DD at a later date.

10.6 CLARIFICATION OF CROSS-REFERENCES

Comment: Commenter IV-D-28 believes § 63.1362(d) of the proposed rule should crossreference only §§ 63.131 through 63.147 because §§ 63.148 and 63.149 are not wastewater

provisions. Commenter IV-D-28 also requested clarification of how to deal with provisions for

Table 8 compounds in the cross-referenced sections. Similarly, other commenters (IV-D-16 and

IV-D-27) believe EPA should clarify that references to Table 8 compounds are not applicable to

this rule.

Response: The EPA agrees with the commenters, and these changes have been

incorporated in the final rule. However, cross-references to § 63.148 from §§ 63.131 through

63.147 are still applicable, and the provisions in § 63.149 have been incorporated directly into

the final rule.
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11.0 STANDARDS FOR BAG DUMPS AND PRODUCT DRYERS

11.1 JUSTIFICATION FOR THE STANDARDS

Comment: Four commenters (IV-D-16, IV-D-21, IV-D-22, and IV-D-29) stated that EPA

should not issue regulations for bag dumps and product dryers because: (1) data are available for

only one source, which is not (commenter IV-D-21 said “may not be”) representative of the

source category; (2) the terms particulate HAP and bag dump are not defined; and (3) no test data

are available to verify estimates. Commenters IV-D-16, IV-D-21, and IV-D-29 also quoted the

following statement from the ruling in Portland Cement Association v. Ruckleshaus, 486 F. 2d

375, 396 (D.C. Cir. 1973): “[A] significant difference between techniques used by the Agency in

arriving at standards, and requirements presently prescribed for determining compliance with

standards, raises serious questions about the validity of the standard.” As a result, the three

commenters noted that the Court remanded the rule, and the commenters concluded that the test

method used for compliance must be closely linked to the test method used as the basis for the

standard. Commenters IV-D-21 and IV-D-29 also recommended that EPA repeal the proposed

provisions for bag dumps and product dryers because they believe the MACT floor was not

established properly per EPA protocol.

Other commenters (IV-D-14, IV-D-20, and IV-D-27) stated that bag dumps should not be

regulated. Commenter IV-D-14 stated that it was inappropriate to include bag dumps in this

standard when no bag dump data were used to determine the MACT floor. According to

commenter IV-D-27, basing a standard for bag dumps on the data from a single product dryer is

inappropriate because the two types of emission points are not comparable. The commenter

explained that a dryer vent is typically a point source that can be easily vented to a control

device, but a bag dump typically is a fugitive emission source that is often difficult to capture and
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route to a control device. According to commenter IV-D-20, EPA should not regulate bag dumps

unless they are a found to be a significant source of emissions; the commenter noted that there

was no data on bag dumps in the PAI data base, and therefore no basis on which to regulate such

emissions. This commenter also cited the following reasons why regulating bag dumps would be

difficult and would not result in any meaningful emission reduction: (1) use of bag dumps is

avoided or minimized to the greatest extent practicable for ergonomic and worker exposure

reasons; (2) any particulate emissions are small and would be controlled to reduce workplace

exposure; (3) if dusting and workplace exposure are not a concern for a particular material, there

may be no process vent associated with the bag dumping operation; and (4) PM10 regulations are

generally applied to larger sources with actual vents. Another commenter (IV-D-16) also stated

that bag dumps should not be regulated as part of this rule because they are a source of fugitive

emissions.

Response: Standards for product dryers and bag dumps were included in the proposed

rule because these emission points can be a source of HAP emissions, specifically particulate

matter HAP emissions. The MACT floor for these emission points was developed for equipment

that emits particulate matter HAP; this equipment was limited to product dryers and bag dumps

because these are the only known sources of particulate matter HAP emissions at PAI facilities. 

The MACT floor also was based on the level of control for these emission points at the MACT

floor facilities (i.e., the nine facilities with the best overall control of PAI process units). One of

the MACT floor facilities dried a PAI that is also a HAP. Emissions from this product dryer

were controlled with a fabric filter, and emissions tests showed the outlet PM concentration was

less than 0.01 grains per dry standard cubic foot (gr/dscf). The floor for particulate matter HAP

emission sources was based on this value because both product dryers and bag dumps are

controlled with fabric filters, and 0.01 gr/dscf is a typical level for fabric filters.

The EPA is not persuaded by the commenter’s argument that bag dumps should not be

regulated because they are (or may be) sources of fugitive emissions and are thus not comparable

to product dryers. The EPA knows of two bag dumps where a HAP raw material is added to a

PAI process, and both are controlled with fabric filters. At a minimum, a hood or partial

enclosure can be placed above or around a bag dump to capture the emissions and route them to
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the control device. Furthermore, one of the commenters also stated that particulate emissions

from bag dumps would be controlled to reduce workplace exposure.

Uncontrolled emissions (i.e., the pre-control emissions) from one of the two known bag

dumps exceed 1.6 Mg/yr. The EPA considers this to be a significant source, and the required

emission reduction to be meaningful. The fact that some facilities may have found more

desirable alternatives to the use of bag dumps does not justify exempting facilities that still use

them from regulation.

As a result, EPA maintains that standards are appropriate for bag dumps and product

dryers that emit HAP, that the MACT floor is valid, and that the standard should be based on the

MACT floor. However, EPA has decided to make one change for the final rule. At proposal, the

standard was for “particulate matter HAP.” For the final rule, the standard is for “particulate

matter” because the material captured in the fabric filters is essentially all HAP, and test methods

are for “particulate matter,” not “particulate matter HAP.” (The EPA assumes this is why the

commenters mentioned linking the test method used as the basis of the standard with the method

used to demonstrate compliance.) The final rule also specifies that the particulate matter

standards are for product dryers that dry a PAI or integral intermediate that is a HAP and for bag

dumps that introduce a HAP to a PAI process unit. See section 5.1 for definitions of “product

dryer” and “bag dump,” and see section 16.3 for a discussion of changes in the monitoring

provisions for these types of emission points.

11.2 LEVEL OF THE STANDARD

Comment: Commenters IV-D-22 and IV-D-27 believe the rule should include an

applicability cutoff. Commenter IV-D-22 stated the cutoff level should be derived from data. 

Commenter IV-D-27 stated that it should be set at the lowest uncontrolled emissions level for a

source that has MACT controls (i.e., the uncontrolled emissions from the single product dryer

used to establish the MACT floor control level) because EPA has no data to support the

0.01 gr/dscf standard on sources with lower emissions. Another commenter (IV-D-14) stated

that the 0.01 gr/dscf standard is not readily achievable using commercially available equipment

and that this level is not typical of fabric filter control. The commenter stated that a typical

vendor guarantee is an outlet particulate concentration of 0.02 gr/dscf for particles above
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2 microns (μm) in diameter, with no guarantee for smaller particles. Consequently, the

commenter recommended that EPA consult with manufacturers of particulate control devices to

ensure that the emission standard is set at a level consistent with vendor guarantees for readily

available equipment.

Response: No mass emission rate cutoff was established because all known bag dumps

that introduce a HAP raw material to a PAI process unit, and all product dryers that dry a product

that is a HAP, are controlled with fabric filters, and EPA believes 0.01 gr/dscf is a reasonable

level for all fabric filters in such applications. An emissions test for the fabric filter used to

control the product dryer at the MACT floor facility provides evidence that this concentration is

achievable. The outlet concentration was less than 0.01 gr/dscf for each of the 12 runs in the test. 

The EPA expects that the existing fabric filters were designed to meet this outlet concentration,

but the standard and associated monitoring requirements are included in the rule to provide

assurance that they will continue to perform at this level. As a result, EPA did not change the

level of the standard, or add an applicability cutoff, for the final rule.
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12.0 POLLUTION PREVENTION STANDARD

Status at proposal. The proposed rule contained a pollution prevention alternative

standard that would allow owners and operators the opportunity to comply with the standards by

demonstrating reductions in the amount of HAP used per unit of product for a given process. 

The pollution prevention alternative standard consisted of two options. Under the first option,

the owner or operator would be required to demonstrate an 85 percent reduction in the

consumption of HAP. The second option would allow a 50 percent reduction in consumption

combined with traditional emission controls to achieve an overall reduction equivalent to the

85 percent reduction specified under option 1. By demonstrating compliance with either of the

pollution prevention options, an owner or operator would satisfy the requirements for all process

vents, storage vessels, wastewater, equipment leaks, and heat exchanger systems associated with

a PAI process unit.

12.1 FORMAT OF THE STANDARD

Comment 1: Two commenters, IV-D-16 and 20, asserted that the 85 percent reduction in

HAP consumption factor should be changed to 75 percent for both pollution prevention options

to be consistent with the Pharmaceutical MACT proposal.

Response: The 85 percent reduction was not changed in the final rule to be consistent

with the value specified in the Pharmaceutical MACT standard because both values were

developed using industry-specific data. The basis for the 85 percent reduction target is the

overall nationwide reduction from uncontrolled emissions that is estimated as a result of the

implementation of the standards in this industry. Although the required reduction “target” was

calculated using the same methodology as that in the Pharmaceuticals MACT standard, the

difference in numerical value is simply due to differences in the impact of the two rules on each
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respective industry. For the PAI production industry, the standards achieve slightly greater

reductions relative to the uncontrolled baseline, which is carried forward to the reduction target

for the P2 alternative.

Comment 2: Commenter IV-G-03 stated that the mechanism to realize pollution

prevention reductions must be maintained in a system that can be managed and provide data that

regulated entities and EPA can use. The commenter asserted that States may not be prepared to

support this regulation with the training requirements of their already overworked staffs.

Response: The Agency agrees with the commenter that the information necessary to

demonstrate compliance with the pollution prevention alternative should be identified, collected,

and managed in a way that minimizes burdens on both the industry and the regulatory agencies

charged with enforcement. Therefore, the final rule requires sources seeking to comply with the

P2 alternative to submit, as part of the Precompliance plan, a P2 demonstration summary that

describes how the P2 alternative will be applied at the facilities, and what tracking mechanisms

will be used to demonstrate compliance with the alternatives. This summary should include

descriptions of how the facility will measure and record HAP consumption and production on a

daily, monthly, and annual basis. The summary should also include appropriate documentation

of how consumption will be tracked such as, but not limited to, operator log sheets, daily,

monthly, and annual inventories of materials and products, and shipment and purchasing records. 

The P2 demonstration summary report allows the owner or operator some flexibility in deciding

the most reasonable and efficient way to demonstrate compliance, while incorporating the

regulatory agency’s review and approval prerogative. Regarding the agency burden, the Agency

believes that compliance with the P2 alternative may actually reduce much of the burden on the

enforcement agency, in that the monitoring, reporting and recordkeeping burden will be reduced

to a material tracking effort, potentially minimizing the amount of data needed to demonstrate

continuous compliance (e.g., monitoring data) for an entire process.

Comment 3: Commenter IV-G-03 requested that EPA strengthen and encourage

pollution prevention alternatives in lieu of command and control regulations. Several

commenters, IV-D-01, IV-D-27, and IV-D-28, recommended allowing any combination of P2
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and end-of-pipe controls to meet the required 85 percent reduction (or lower value, as noted in

comment 1 above) for P2 because:

1. The requirements of option 2 would be impossible to achieve if less than 70 percent of

the remaining HAP after P2 is in the air stream (even if it were all controlled). Also, if more than

90 percent control is needed, there is no incentive to use P2.

2. Implementing P2 practices that achieve less than 50 percent of required reductions in

conjunction with add-on controls would bring overall removals to levels equal to or greater than

that required by the standard.

3. Option 2 places unnecessary constraints on the type of control device that can be used

to obtain required reductions, beyond that achieved by P2.

4. Proposed P2 is only viable if a fundamental change has occurred; sources should be

allowed to take credit towards the conventional standards for more limited P2 activities.

5. If P2 achieves reduction of 65 to 85 percent, it would be impossible to achieve the

additional requirement for 35 percent reduction from add-on controls.

6. Option 2 provides incentives for unsound environmental practices (destruction of

recovered material instead of reuse).

Commenter IV-D-27 suggested allowing sources to comply with 90 percent of any

applicable standard if at least 50 percent of the reductions are the result of P2, as an alternative to

the above comment.

Response:. In response to the comments, EPA stresses that the P2 alternative is an

alternative to the standards in the rule. As such, the Agency has flexibility in developing

requirements that may provide alternative approaches for compliance, but is charged with

preserving the reductions that would have been achieved through compliance with the standards

themselves. Under Option 2, EPA required that a significant portion (50 percent) of the

reductions be achieved using P2 techniques, not add-on controls. Without such a restriction,

owners and operators could attempt to use add-on controls entirely in meeting the P2 target

reductions, which might result in reductions that are less than those required by the standards. 
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For example, the process vent standard requires a 90 percent reduction in the HAP emissions

from affected processes, not an 85 percent reduction.

In an effort to ensure the emission reductions from the P2 alternative are at least

equivalent to the emission reductions achieved by the standards, the reduction target for the P2

consumption factor was linked to the predicted reductions from the nationwide uncontrolled

emissions through implementation of the standards. It was always the Agency’s intent that these

reductions would be achieved primarily through P2 techniques. In recognition of the difficulties

associated with achieving such high consumption reduction targets (85 percent), however, the

Agency developed Option 2 to allow some of the reductions to be achieved using add-on

controls. For these reasons, the Agency disagrees, in general, with the comments suggesting

lesser reductions in both the overall target of 85 percent and the requirement that at least

50 percent of the reduction be attributed to the P2 alternative. However, the Agency agrees with

the comments that option 2 as proposed is unworkable if the reduction achieved by P2 exceeds

50 percent of the required amount. For the final rule, option 2 was revised to require that at least

50 percent of the reduction be achieved using P2 and that the remainder of the 85 percent,

however much is needed, to be achieved using conventional controls.

Secondly, the Agency stresses that the restrictions on the types of add-on controls allowed

to be considered in addition to the P2 reductions in meeting the overall target are in place to

guard against double-counting of emission reductions; for example, control via a technique that

recycles HAP material back to the process is an environmentally beneficial technique and is

encouraged. However, the recycling effect will also reduce the consumption of HAP; therefore,

the recycling is already considered. To further reduce the consumption factor by the control

achieved by the condenser would result in double counting of emissions.

12.2 POLLUTION PREVENTION FOR REACTANTS AND GENERATED HAP

Comment: Commenter IV-D-27 stated that P2 should be allowed for HAP generated in a

process. Commenter IV-D-28 indicated that the rule was not clear on how to comply when the

HAP generated in the process is the same as that introduced. Commenter IV-D-15 noted that

these exclusions would prevent them from using P2 and suggested that the rule include TRE

calculations like in the HON as a way to provide more cost-effective alternatives for processes
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that are prohibitively expensive to control (i.e., that would exclude such processes from the

requirements of the conventional standards).

Response: The Agency reviewed the language contained in the proposed standard and

has revised it to capture the Agency’s intent in restricting the use of the alternative in situations

where HAP’s are generated, without prohibiting its use altogether. The Agency’s concern, in

adding the restriction to the proposed standard, was that HAP generated in a process would not

be addressed through the pollution prevention alternative because it requires only a reduction in

the consumption of HAP that are actually brought into the process. Therefore, a situation could

exist in which a process could be exempted from control because the production-indexed

consumption factors were reduced by adequate amounts (85 percent), while a potentially

significant amount of HAP, which happened to be generated in the process, could still be

emitted. The EPA agrees with the commenter that sources that generate HAP should be eligible

for the P2 standard, provided the HAP generated by the source are included in the analysis. 

Therefore, the final rule allows owners and operators to use the P2 alternative for processes that

generate HAP that are not part of the production-indexed consumption factor (e.g., the HAP

generated are different from the HAP brought into the process), provided the following

conditions are met: (1) emissions of generated HAP are controlled to the levels required by the

applicable provisions for storage vessels, process vents, wastewater, and equipment leaks; and

(2) the P2 requirements are applied to the HAP that are added to the process. For the final rule,

the definition of consumption has been revised to consider quantities of HAP that are generated

by the process as well as those that are brought into the process, provided the HAP generated in

the process is the same as one (or more) of the HAP added to the process.

A related issue is the tracking of the VOC consumption-indexed production factor and the

proposed rule’s requirement that this factor should not be increased as a result of pollution

prevention. Although this issue was not specifically commented on, EPA also revised the

language of the final rule regarding the production-indexed VOC consumption factor. In

developing the pollution prevention alternative, EPA’s intention was to recognize those

processes that have reduced or will reduce the amount of HAP solvents used in the manufacture

of PAI’s as viable alternatives to add-on controls. By preventing affected sources from
12-6

increasing the production-indexed VOC consumption factor, EPA intended to prevent solvent

substitutions that merely replaced HAP with VOC. After reviewing the proposed pollution

prevention standard, EPA realized that the proposed standard gave an unfair advantage to

affected sources that use VOC-HAP solvents as opposed to non-VOC-HAP solvents. As

proposed, the rule did not allow affected sources using non-VOC-HAP solvents to switch to lowVOC solvents and still qualify under the pollution prevention alternative because such a switch

would increase the production-indexed VOC consumption factor. However, affected sources that

use VOC-HAP solvents could switch to low-VOC solvents as long as the production-indexed

VOC consumption factor did not increase. The EPA’s intention in the final rule is that pollution

prevention be accomplished through reductions in solvent usage as opposed to solvent

substitution. After consideration, EPA changed the final rule to require an equivalent reduction

in the production-indexed VOC consumption factor, if the reduction in the production-indexed

HAP consumption factor is achieved by reducing a HAP that is also a VOC. If the reduction in

the production-indexed HAP consumption factor is achieved by reducing HAP that is not VOC,

the consumption-indexed VOC factor may not be increased. In making these changes to the final

rule, EPA essentially eliminated the possibility of receiving credit, through the pollution

prevention alternative, for substituting VOC for HAP.

12.3 COMPLIANCE PROCEDURES

Comment: Commenter IV-D-28 stated that the P2 requirements have insufficient

safeguards against cheating. As examples, the commenter suggested that a facility could: 

(1) claim a reduction for shutting down one process unit, (2) calculate current usage using

detailed information while inflating baseline emissions by using conservative assumptions in the

calculation, or (3) falsely assigning an inflated proportion of a site’s historic emissions to a PAI

process without detailed supporting data. Commenter IV-D-28 also asserted that toxic release

inventory (TRI) data are not accurate enough to use for compliance determinations.

Response: As stated previously, the final rule requires owners and operators electing to

use the P2 alternative standard to submit a plan for demonstrating compliance with the

alternative. This plan must be reviewed and approved by the reviewing agency prior to the

implementation of the standard. Claiming a reduction for shutting down a process would be
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rejected because a facility must show either consumption reductions or emission reductions for a

given process; consumption reductions on one process cannot be used to demonstrate compliance

for a different process. Also, the Agency believes that TRI data can be used to set the baseline

consumption factor if it can be linked to the process. The data contained in the TRI reports

essentially provide a mass balance of TRI chemicals brought onsite or produced, and their

environmental fates (air emissions, discharges to water, onsite or offsite destruction, etc.).

However, because TRI data are reported from the facility as a whole, it may not be feasible to

link data to individual processes, negating this approach for many facilities. The EPA also notes

that TRI data have been allowed to demonstrate applicability with respect to synthetic minor

status for other rules such as the HON. In any case, the regulatory agency will be charged with

assessing the adequacy of the compliance method prior to approval.

12.4 RECORDKEEPING

Comment: Commenter IV-D-28 suggested that the rule allow at least a couple of weeks

from the end of each 30-day period before the owner or operator has to complete the rolling

average calculation.

Response: The EPA believes that it is important to determine if a violation has occurred

as soon as possible. For the P2 alternative, compliance is determined by calculating the

production-indexed consumption factors for operation over every 30 days for continuous

processes and every 10 batches for batch processes. These calculated factors must be reported in

the semiannual periodic reports, and each periodic report is due 60 days after the end of the

applicable reporting period. The consumption and production data must be collected for each

applicable 30-day or 10-batch period, but the calculations may be performed at any time prior to

submission of the periodic report. However, a violation will be charged to all days in which the

P2 factor was exceeded. Therefore, it is in the operator’s best interest to discover an exceedance

and correct the problem as soon as possible to minimize the number of days that are included in

the period of violation.
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12.5 BASELINE YEAR

Comment: Commenter IV-D-28 stated that the compliance options appear to reward

“laggards” while penalizing companies that implemented pollution prevention early. A company

that has not paid as much attention to pollution prevention may be able to comply by

implementing only pollution prevention, whereas a company that implemented pollution

prevention changes early may not have room for further improvement by pollution prevention

and thus be forced to install expensive emission control equipment to comply with the standard. 

Response: During the development of the standard, EPA considered 1987 to be the

earliest year to set the baseline factor. The final rule has been revised to comprise a 3-year

average beginning no earlier than 1987, or the first year the process was operating, if 3 years of

data are not available, to account for sensitivity in data quality. The Agency notes that the P2

standard actually rewards people for making a noticeable improvement over time. For

companies that have been proactive in minimizing wastes, including air emissions, from periods

of time prior to 1987, and, as a result, may not be able to take advantage of the P2 alternative, the

Agency believes that the rule also provides relief in the form of the cutoff based on controlled

emissions that is contained in the final rule for process vents. The Agency also notes that the

compliance date for the standard, in 2002, is approximately 15 years later than the 1987 baseline

and should provide an adequate window for demonstrating reductions.
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13.0 EMISSION AVERAGING

13.1 COMPLEXITY OF METHODOLOGY

Comment: Commenter IV-D-28 supported the concept of emissions averaging, but noted

that the provisions are so complex and burdensome that many owners and operators may be

deterred from using this option. 

Response: The emissions averaging provisions provided in the proposed rule are

identical to those included in the HON. Further, the requirements are necessarily complex

because of the increased flexibility of the compliance approach provided by the provisions. As

stated in the HON promulgation preamble discussion, the EPA’s goal in crafting the emissions

averaging provisions was to make emissions averaging available to sources faced with

controlling emission points that are particularly difficult or costly to control, while maintaining

the ability to demonstrate compliance with the standard.

13.2 RESTRICTIONS ON EMISSIONS AVERAGING

Comment 1: Commenters IV-D-16 and IV-D-27 suggested that EPA set a nominal

control efficiency for combustion devices used for air emission control for storage tanks and/or

wastewater at 98 percent. Commenter IV-D-27 asserted that EPA’s wording in § 63.1362(k)(2)

of the proposed rule inappropriately restricts sources equipped with controls listed in that section

from generating emissions averaging credits.

Response: The Agency believes that the commenters would like to equate 98 percent

control to the performance specifications provided in the proposed rule for combustion devices

used for air emission control for storage tanks and/or wastewater sources. The Agency does not

agree that a nominal 98 percent should be assigned to these devices. Although EPA did establish
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these performance specifications, EPA maintains that testing is important to ensure that a control

device can achieve the reported efficiency. For these reasons, EPA has required performance

testing on combustion devices that control greater than 9.1 Mg/yr of HAP. Therefore, EPA will

not allow credits based on a control efficiency that has not been demonstrated. Secondly, the

provisions of § 63.1362(k)(2) incorrectly referred to the 98 percent and 95 percent control levels

as “nominal” control efficiencies. These efficiencies must be demonstrated via performance

testing and therefore should not be restricted from obtaining credits in emissions averaging. The

final rule corrects this oversight. 

Comment 2: Commenters IV-D-16 and IV-D-27 believe EPA should delete the

restrictions that prohibit a source from calculating emission averaging credits for emission

reductions achieved prior to November 15, 1990 or with equipment installed to comply with

other State/Federal rules. The commenters believe these restrictions (1) are arbitrary, (2) are not

dictated by the Act, (3) unfairly limit economic incentives and thus impose unreasonable costs,

(4) penalize progressive companies, and (5) are inconsistent with procedures to develop the floor

(i.e., emission points that would be excluded from emissions averaging are used in setting the

standard). In addition, commenter IV-D-27 believes EPA’s response to comments in the April

22, 1994 Federal Register notice on the HON are inadequate to justify the restriction.

Response: The Agency’s policy on not allowing averaging of emission reductions for

controls in place prior to the passage of the 1990 CAA amendments was explained in the

April 22, 1994 Federal Register notice for the promulgated HON (59 FR 19426), and this

rationale is still applicable. In general, the emissions averaging provisions are designed to

provide an owner or operator with flexibility in designing a compliance strategy that optimizes

the use of existing controls, rather than replacing them. However, the final rule does not allow

credit for emissions reductions achieved by control devices installed before November 15, 1990

because EPA policy is that regulations must achieve additional reductions beyond what would

have occurred in the absence of the amended Act. Emission reductions achieved by controls that

were in place prior to November 15, 1990 would have occurred regardless of whether or not the

CAA was amended. If the rule allowed a source to take credit for these preexisting emission

reductions, the source could increase its emissions above the 1990 baseline levels. Regarding the
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commenter’s view that the restrictions penalize progressive companies, the Agency notes that, at

least for process vents that meet the applicability criteria for 98 percent control, owners and

operators who can demonstrate that controls achieving the MACT floor level of control

(90 percent) were in place prior to the proposal date of these standards, are not required to

achieve the higher efficiency requirement of 98 percent. In this manner, companies who have

taken proactive measures to control emissions are actually rewarded. Additionally, the pollution

prevention alternative standard also rewards facilities who have demonstrated significant

reductions in their production-indexed consumption factors. Finally, these provisions have been

included in numerous regulations beginning with the HON, and they have been reviewed and

approved by OMB.

Comment 3: Commenters IV-D-16 and IV-D-27 objected to restrictions on emissions

averaging for “new sources.” The commenters disagreed with EPA’s rationale in the preamble

that this approach holds new sources to a stricter standard and that flexibility is unnecessary for

new sources. The commenters argued that using emissions averaging is the more stringent

approach because of the 10 percent discount factor that is applied to credits. Furthermore, the

commenters stated that new sources also need flexibility to comply with the standard in the most

economical and efficient manner; for example, if a new source is added to an existing facility

there may be opportunities to route emissions from the new source to existing controls, or to

overcontrol certain existing or new emission points to provide equal or greater environmental

benefit at lower cost. Also, commenters believe this restriction unfairly limits economic

incentives and imposes unreasonable costs.

Response: The EPA’s policy on not allowing averaging of emission reductions for new

sources was explained in the April 22, 1994 Federal Register notice for the promulgated HON

(59 FR 19427), and this rationale is still applicable. As noted above, EPA designed emissions

averaging provisions to provide existing sources with flexibility in achieving compliance. 

Instead of requiring the replacement of all existing controls that do not meet the level of the

standard, the emissions averaging provisions allow an existing source to optimize the use of

existing controls in the most economical and technically feasible fashion. The EPA maintains

that this concern does not apply to new sources because the owner or operator of a new source
13-4

would be able to integrate state-of-the-art controls into the design of the new source. However,

nothing in the rule prevents an owner or operator from routing emissions from a new PAI process

unit to an existing control that meets the required control levels. Finally, as noted in the previous

response, these provisions have been included in numerous regulations beginning with the HON,

and they have been reviewed and approved by OMB.

Even if emissions averaging were allowed for new sources, certain other factors may limit

its feasibility for new sources. For example, new sources are subject to PSD/NSR review that

may require levels of control similar to those in the rule for new sources. In addition, because the

level of stringency in the new source standards is high (98 percent), achieving credit above and

beyond the 98 percent levels is probably unrealistic in most situations.
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14.0 TESTING PROVISIONS

14.1 TESTING CONDITIONS

Status at Proposal: Under the proposed rule, inlet and/or outlet emissions testing on a

control device would be required if the HAP load to the control device from all sources exceeded

10 tons/yr. This testing would be required under absolute, representative, or hypothetical peakcase conditions. Any device could be tested under absolute or hypothetical peak-case conditions;

testing under representative conditions would be limited to thermal incinerators, wet scrubbers,

and carbon adsorbers.

Absolute peak-case conditions were defined by any of three conditions: (1) the period in

which the inlet to the control device contains at least 50 percent of the maximum HAP load

capable of being vented to the control device over any 8-hour period, (2) a 1-hour period in

which the inlet to the control device contains the highest HAP mass loading capable of being

vented to the control device, or (3) for a condenser as the control device, the 1-hour period of

time in which the gas stream capable of being vented to the condenser would require the

maximum heat removal capacity to cool the stream sufficiently, based on calculations, to achieve

the required removal efficiency. Hypothetical peak-case conditions would be simulated test

conditions that contain the highest hourly HAP load predicted to be vented to the control device. 

For both absolute and hypothetical peak-case, the owner or operator would be required to

develop an emissions profile to identify the appropriate time period, and the profile would be

based on all streams vented to the control device, not just streams from PAI processes. The

owner or operator would develop the emissions profile based on process knowledge, engineering

analyses, or test data. Existing test data could be used, provided the data characterize current

process vent stream conditions.
14-2

Representative peak-case conditions would be based on the 1-hour period that contains

the highest HAP mass loading rate from a single process, or for a condenser, the 1-hour period in

which the vent from a single process requires the maximum heat removal to cool the stream

sufficiently to achieve the required removal efficiency. In both cases, testing would be

conducted while that single process is venting, with or without simultaneous vents from other

processes.

 Compliance would be demonstrated based on the results of a single run for runs that

exceed 1 hour, and three runs would be required if the duration of a run was less than 1 hour. 

The owner or operator would not be required to conduct test runs exceeding 8 hours, even if the

duration of emissions from a process vent exceeded 8 hours.

Comment 1: Three commenters (IV-D-16, IV-D-20, and IV-D-27) requested that EPA

simplify the performance testing requirements. Commenter IV-D-20 stated that the performance

testing requirements for process vents must be simplified and aligned with the annual average

survey data on which the standards are based. Commenters IV-D-16 and IV-D-27 found the

“absolute,” “representative,” and “hypothetical” peak-case testing conditions in

§ 63.1364(b)(11)(ii) of the proposed rule to be extremely confusing. They suggested simplifying

the provisions; commenter IV-D-27 provided the following language, and commenter IV-D-16

provided a slight variation:

Testing shall be performed under actual or simulated conditions (based on an emissions

profile) that includes any of the following at a minimum:

(1) at least the 1-hour time period with the highest mass loading rate (or maximum heat

removal requirement for condensers) of regulated pollutant to the control device, or 

(2) the time period that contains at least 50 percent or the maximum mass loading rate (or

maximum heat removal for condensers) of regulated pollutant vented to the control device over

any 8-hour period.

Response: The Agency agrees that the wording in this portion of the proposed rule is

confusing. Therefore, in the final rule, EPA has made several changes to the testing language

that generally cover the commenter’s suggested revisions, but also allow more flexibility in

defining the peak-case. These changes include the elimination of the option to test under

representative peak-case conditions and the elimination of testing requirements for condensers. 

Additionally, EPA has expanded the testing language to cover factors other than the highest HAP
14-3

load that also impair control efficiencies (i.e., the most challenging conditions for the control

device). These other factors that limit control efficiencies relate to characteristics of components

and the operating principles of the control devices. For example, the solubility of an emission

stream component in scrubbing media, or the affinity of an emission stream component for

carbon can also define the most challenging conditions for a particular control device. These

changes are described in more detail in the responses to comments 2 and 3 in this section and to

the response to comment 1 in section 14.5. The EPA is not sure what the commenter means by

aligning the performance testing with annual average survey data; however, as discussed in

responses to comments in sections 7.5 and 16.1, EPA does not believe the survey data are

applicable only on an annual basis.

Comment 2: Commenter IV-D-28 believes the requirement to test under peak-case

conditions should be deleted from the rule and replaced with a provision that allows testing under

representative conditions. The commenter cited the following reasons: (1) the peak-case

conditions might mistakenly be interpreted to mean they apply during startup, shutdown, and

malfunction; (2) the validity of a performance test depends more on the operating conditions of

the control device than on the operating conditions of the process; (3) other regulations have

allowed testing under representative conditions; (4) planned production schedules may not

produce the peak-case conditions before the deadline to demonstrate compliance, which would

mean operating for a test at higher or lower production rates than demand would dictate; and

(5) typically, the organic HAP reduction efficiency of a control device is fairly stable across a

wide range of HAP concentrations. Alternatively, if the peak-case concept is retained in the final

rule, the commenter recommends adding three provisions limiting the timing of testing. 

Specifically, the commenter seeks assurances that a facility would not be required to operate

(1) at a rate, or in a manner, that could reasonably be expected to damage the process, control

device, or monitoring system; (2) in a manner that would produce unmarketable product (i.e.,

does not meet customer specifications); or (3) at a rate that would produce product in excess of

demand.

Response: The intent of compliance testing under peak-case conditions is to document

the reduction efficiency of the control device under the most challenging conditions. This
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documentation is necessary to assure compliance in cases where the process operations yield

emission stream characteristics that may vary significantly over time, and where conditions

approaching absolute peak-case may occur. Subsequent to the initial compliance test, continuous

monitoring of operating parameters established during the test is a reasonable measure of

continuous compliance with the efficiency requirement under all conditions. Presumably, the

control device should function as well or better under conditions that are not as challenging. 

Although EPA is sensitive to unnecessarily increasing the burden associated with testing

of control devices for little benefit, the Agency still has concern that testing under

“representative” conditions (where “representative” is defined either as in the proposed rule for

representative peak-case or as a more general concept suggested by the commenter) may not be

sufficient to demonstrate that the control device will achieve required efficiencies under all

conditions. This is especially important as it relates to the continuous compliance demonstration

provision. Therefore, the option to test under representative peak-case conditions has been

eliminated for the final rule, and testing under representative conditions has not been added.

The final rule, however, does allow more flexibility in defining absolute and hypothetical

peak-case conditions. The definition of absolute peak-case load in the final rule incorporates the

possibility that conditions other than the highest HAP loading constitute the most challenging

conditions for the device. These conditions include, but are not limited to, periods when the

emissions to the device may contain the highest combined VOC and HAP load, periods when the

streams contain HAP constituents that approach limits of solubility for scrubbers, or periods

when the streams contain HAP that approach limits of adsorptivity for carbon systems.

The hypothetical peak-case conditions have also been expanded. In addition to

establishing hypothetical peak-case testing conditions based on a calculation of maximum actual

emissions, the final rule allows hypothetical peak-case conditions to be defined based on

equipment design features that limit the maximum hourly emissions that can be routed to the

control device. For example, a fan may limit the flowrate, and the concentration may be limited

to a certain percentage of the lower explosive limit before a bypass valve opens.

The Agency does not believe that the testing provisions in the final rule require operation

in a manner that could damage equipment, because the testing is only required for conditions that
14-5

have some reasonable likelihood of occurring. Thus, the design of the system should have

considered the possibility of operating under these conditions.

Regarding the comment that the testing provisions should not require operation in a

manner that produces excess or unmarketable product, or in a manner that will not occur within

the time frame allotted prior to the compliance date, the Agency concedes that some

inconvenience to the source may occur, but believes that in most situations, facilities will be able

to work within the confines of the definitions to arrive at a set of testing conditions that minimize

production disruptions. The EPA notes that the requirement for submittal of the site-specific test

plan is also an opportunity for the facility to present site-specific information that may influence

the selection of testing conditions. The EPA encourages owners and operators to work with the

permitting agencies to arrive at solutions that meet the intent of this regulation. 

Comment 3: Two commenters (IV-D-16 and IV-D-27) believe testing under

representative peak-case should not be limited to only thermal incinerators, carbon adsorbers, and

wet scrubbers.

Response: As discussed above, EPA has not allowed representative peak-case testing

under any circumstances because the Agency believes that the initial compliance demonstration,

which is used, in part, to set conditions for the continuous compliance demonstration, must be

conducted at the most challenging conditions. Therefore, testing is required under absolute peakcase conditions or under simulated hypothetical peak-case conditions.

Comment 4: According to commenter IV-G-03, peak-case conditions that are not

relevant to an 8-hour or 1-hour condition need to be addressed.

Response: As described above, the final rule requires that control devices used to control

emissions from batch operations must be conducted under either absolute or hypothetical peakcase conditions. These peak-case conditions are identified based on the results of an emissions

profile. All sources of emissions to the control device, including scheduling restrictions, are

considered in the emissions profile; alternatively, limitations of the equipment are identified. 

From the emissions profile, the 1-hour or 8-hour period that defines the peak-case conditions is

determined. Thus, by definition, peak-case conditions are relevant to 1-hour or 8-hour periods. 
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If the most challenging conditions are not based on the highest load, the emissions profile and the

peak-case conditions are still determined over hourly periods.

14.2 TEST PLAN

Comment: Commenter IV-D-28 believes that preparation of a site-specific test plan is

unduly burdensome, produces no discernible benefit, and should not be required. Therefore,

Table 1 also should indicate that § 63.7(c) of the General Provisions is not applicable.

Response: All section 112 MACT standards require the owner or operator to develop a

site-specific test plan in accordance with § 63.7(c) of the General Provisions. In the PAI rule

EPA requires that this site-specific plan be submitted. The test plan is needed because of the

complexity of identifying the most challenging conditions for testing.

14.3 EMISSION PROFILE

Comment 1: Section 63.1364(b)(11)(iii) of the proposed rule specified how to develop

an emission profile. One sentence in that section was the following: “Previous test results may

be used provided the results are still relevant to the current process vent stream conditions.” 

Commenter IV-D-28 requested that the phrase “with or without adjustment” be added to the end

of that sentence.

Response: Generally, the Agency’s position regarding the requirement of testing under

the most challenging conditions will not allow the use of data that have been collected under test

conditions that do not meet those specified in the final rule. However, if the conditions under

which the testing was originally conducted represent more challenging conditions than the

current operation, the rule provides a mechanism for owners and operators to extrapolate the

results of the initial test down to current operations, provided the methodology is presented in the

Precompliance plan and approved.

Comment 2: According to two commenters (IV-D-16 and IV-D-27), the rule should state

that development of an emission profile is not required if testing will be performed over the

duration of a complete batch cycle.

Response: An emission profile is needed to identify the period of time that constitutes

the most challenging conditions for the control device. The content of the emission profile will
14-7

vary depending on the circumstances. The most straightforward control scenario is one in which

a control device is dedicated to vent streams from a single process, and a test run can encompass

all of the emission events that are vented to the control device. For this situation, an acceptable

emission profile would describe the situation and explain how it meets at least one of the criteria

that define the absolute peak-case conditions. This simplified approach would not be acceptable

if streams from multiple processes are routed to the control device, even if the test were to be

conducted over the duration of the batch.

14.4 TEST DURATION

Comment: Several commenters (IV-D-16, IV-D-27, and IV-D-28) requested clarification

of the test duration requirements in §§ 63.1364(b)(11)(iv) and (v) of the proposed rule. 

Commenters IV-D-16 and IV-D-27 stated that for continuous process vents, sources should be

allowed to test for longer than 1 hour per run, and commenter IV-D-28 asked for clarification of

this provision because it sounds as if three runs must be conducted in the same period of 1 hour

or less. These two commenters also stated that for batch process vents, sources should be

allowed to test for the entire length of a batch, even if it is longer than 8 hours. Similarly,

commenter IV-D-28 requested that EPA revise the language of the provision for batch process

vents to indicate that sources are not required to test for more than 8 hours per run, but that they

are not prohibited from conducting longer tests. Commenter IV-D-28 requested clarification that

the 8 hours of testing applies only to vents from batch processes, not continuous processes. 

Commenter IV-D-28 also requested that EPA edit the phrase “. . . process vents of duration . . .”

because it is the emission episode, not the vent, that has a duration.

Response: The final rule requires that three test runs with a minimum duration of 1-hour

each be conducted during the initial compliance demonstration. For consistency, each run must

be conducted over the same set of conditions. 

14.5 CLARIFICATIONS

Comment 1: Commenters IV-D-16 and IV-D-27 requested clarification of the ways to

characterize the various peak conditions for condensers. They noted that in

§§ 63.1364(b)(11)(ii)(A) and (B) of the proposed rule absolute and representative peak-case

conditions for condensers are based on the maximum heat load, rather than the HAP load, that is
14-8

used to define these conditions for other types of control devices. However, in

§ 63.1364(b)(11)(ii)(C) of the proposed rule, hypothetical peak-case for all control devices is

only based on the HAP load. The commenters believe maximum heat load should be used to

characterize hypothetical peak-case for condensers.

Response: The commenters identified an oversight in the proposed rule. However, rather

than implement the change the commenters requested, EPA has decided, for other reasons, to

delete the requirement to identify the period of maximum heat removal in an emissions profile

for absolute peak-case conditions (and as noted above, the final rule does not allow testing under

representative peak-case conditions). See the response to the comment in section 15.2.5 for a

discussion of the initial compliance procedures specified in the final rule for condensers.

Comment 2: Commenters IV-D-16 and IV-D-27 requested that EPA modify the language

in the testing conditions section of the rule to clarify that use of the terms “HAP load” and “HAP

concentration” means the specific class of HAP (either organic HAP or HCl/Cl2) for which the

performance test is conducted.

Response: Section 63.1365(b)(11) in the final rule includes a statement specifying that

the term “HAP mass loading,” as used in that section, refers to the class of HAP that the control

device is intended to control. As a result of the revisions to the provisions for condensers (see

section 15.2.5), the term “HAP concentration” is not used in § 63.1365(b)(11) of the final rule.

Comment 3: Commenter IV-D-28 requested clarification of the phrase “capable of being

vented” in the description of maximum HAP loads for absolute peak-case in

§§ 63.1364(b)(11)(ii)(A)(2) and (3) of the proposed rule. The commenter speculated that it could

mean legal limits, maximum production, abnormal venting during a malfunction, hypothetical

scenarios, or control device capacity.

Response: The intent of the phrase “capable of being vented” is that the absolute peakcase conditions are to be based on the most challenging conditions for the control device. The

emissions profile is to be used to determine and document these conditions, and in developing

the emissions profile the owner or operator may consider factors such as legal limits, maximum

production rates, hypothetical scenarios, and/or control device capacity. All of these factors are

related to production scheduling. Therefore, the final rule clarifies the description of absolute
14-9

peak-case by specifying that the emission profile for absolute peak-case is to consider production

scheduling. The most challenging conditions for absolute peak-case conditions are not based on

“abnormal venting during a malfunction” because the emission limitations do not apply during

periods of malfunction. In § 63.1365(b)(11)(i) of the final rule, the phrase “capable of being

vented” has been changed to “that may be vented.”

Comment 4: Commenter IV-D-28 believes the testing requirements are covered so

completely in § 63.1364 of the proposed rule that there seems to be no need to say § 63.7(e)(3) of

the General Provisions is also applicable. If anything from § 63.7(e)(3) not yet in § 63.1364 is

needed, the commenter suggests that the rule more precisely identify it.

Response: Section 63.7(e)(3) of the General Provisions contains additional requirements

for test data reduction that are not completely covered in § 63.1364 of the regulation. The

Agency commonly references various portions of the General Provisions without re-writing the

contents of each reference verbatim in the regulation. Therefore, the final rule retains a reference

to the applicable portions of the General Provisions.

Comment 5: Section 63.134(b) of the proposed rule would require that Methods 2, 2A,

2C, 2D, 3, and 4 be performed twice during each test period. Commenter IV-D-28 asked why

this provision is necessary.

Response: For the final rule this provision was deleted to be consistent with the sampling

times in Appendix A of 40 CFR Part 60.

Comment 6: Commenter IV-D-28 requested that the rule not require the use of specific

units except when necessary. For example, in § 63.1364(b)(11), the commenter indicated that

there is no reason to require that maximum heat removal, mass loading rates, and duration be

expressed only in kilowatts, kg/hr, and hours, respectively.

Response: The Agency agrees with the commenter that many of the quantities that an

owner or operator is required to calculate (such as mass loading rate) do not need to be expressed

in only one set of units. The Agency has modified the final rule where appropriate to allow

owners or operators the option to choose the specific units that they want to use, and that are

acceptable to the implementing agency.
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15.0 INITIAL COMPLIANCE DEMONSTRATIONS

15.1 GENERAL

Comment 1: Commenter IV-D-28 believes that an owner or operator should be allowed

to deem a stream to be a Group 1 stream, and that for such streams there should be no

requirement to calculate, estimate, or otherwise determine Group status.

Response: Since proposal, EPA re-examined the procedures for determining Group 1

process vents, storage vessels, and wastewater streams. The proposed rule would allow owners

or operators to designate a wastewater stream to be a Group 1 stream, and this provision is

retained in the final rule. As a result of the review, EPA changed the final rule to allow owners

and operators the option to designate any storage vessel as a Group 1 storage vessel, but

determined there is no reason to designate Group 1 process vents. Rationale for the decisions

regarding storage vessels and process vents are described in the remainder of this response.

For storage vessels, Group status is required for determining applicability of the standard,

and it is used in emissions averaging. As noted in chapter 8, the applicability cutoffs for the

storage vessel standard have been changed from both the annual mass emissions and tank size

under the proposed rule to both the maximum true vapor pressure and tank size under the final

rule. These characteristics are also used to determine Group status. Designating that a storage

vessel stores material with a maximum true vapor pressure above the applicability cutoff (or

below the size cutoff) is acceptable because it results in control that is equal to or more stringent

than the standard and has no impact on emissions averaging calculations. Thus, the final rule

allows an owner or operator to designate a storage vessel as a Group 1 storage vessel, but the

owner or operator may still need to determine the maximum true vapor pressure for a compliance

demonstration. For example, if the owner or operator conducts a design evaluation or controls
15-2

emissions from the storage vessel with a condenser, the owner or operator may elect to use the

maximum true vapor pressure in emissions calculations.

Determining Group status for process vents is needed only to identify Group 1 process

vents for which debits must be calculated; it is not needed to comply with the regular standard. 

To determine Group status, the owner or operator must calculate the uncontrolled emissions from

all process vents within a process. Because this same information is needed to calculate debits

for emissions averaging, designating process vents does not reduce the burden to comply with the

emissions averaging provisions. However, there are situations for which the owner or operator

would not be required to calculate uncontrolled emissions as part of the compliance procedures. 

For example, uncontrolled emissions are not needed if the owner or operator complies with the

alternative standard; thus, this compliance procedure has the same effect as designating the vents

as Group 1 process vents.

Comment 2: Commenter IV-D-18 believes the regulation should include compliance

procedures for catalytic incinerators. The commenter indicated that the design evaluation would

include a minimum temperature requirement for the destruction efficiency, the stream’s flow

rate, and a minimum residence time.

Response: Catalytic incineration is a viable control option for the PAI production

industry, just as it is for the synthetic organic chemicals, pharmaceuticals, and other industries. 

The rules that apply to these other industries include design evaluation criteria (and monitoring

criteria) for catalytic incinerators. To be consistent, these criteria have also been added to the

final PAI rule,

Comment 3: Commenters IV-D-18 and IV-D-28 addressed the provision in

§ 63.1364(c)(3)(ii)(B) of the proposed rule that requires an owner or operator to correct the outlet

TOC emissions to 3 percent oxygen. Commenter IV-D-18 disagrees with this provision because

many thermal and catalytic incinerators properly operate with higher oxygen levels in the exhaust

stream. Therefore, this commenter believes that the measured outlet concentration of TOC

should be corrected to the design oxygen content in the outlet stream. Commenter IV-D-28

stated that § 63.1364(c)(3)(ii)(B) should require concentration corrections to 3 percent oxygen

only for combustion devices. 
15-3

Response: The general provisions prohibit the use of dilution as a means of achieving

compliance with a standard (see 40 CFR 63.4(b), Circumvention). However, EPA also

recognizes that there are valid reasons for introducing air or inert gases into manifolds for safety

or design considerations. For example, supplemental combustion air may be required for proper

operation of an incinerator. The intent of the proposed requirement for correction to 3 percent

oxygen was to allow an owner or operator to add supplemental combustion air, but only take

credit for the amount that is needed for proper operation. As one commenter noted, this

correction was not intended to apply to other types of control devices.

The correction to 3 percent oxygen concentrations was drawn from the HON and the

earlier SOCMI NSPS. Under these rules, this correction is required for purposes of

demonstrating compliance with a 20 ppmv outlet concentration standard. The value of 3 percent

originates from good engineering practices. For oxygen deficient streams, if the proper amount

of supplemental combustion air is added, the outlet stream would contain approximately 3

percent oxygen. Typically, SOCMI facilities have low oxygen, high VOC/HAP concentration

streams that generally require supplemental combustion air when they are combusted. Therefore,

a correction to prevent dilution was needed in rules for the SOCMI industry.

A similar requirement to correct the outlet concentration was included in the Polymer

Manufacturing NSPS. Commenters on the proposed NSPS asserted that an oxygen correction

may be appropriate for oxygen deficient streams to which supplemental combustion air is added

to ensure combustion of the emissions, but it is not appropriate for high oxygen, low VOC

concentration streams. The commenters on the proposed NSPS further stated that requiring an

oxygen correction for processes with inherently high oxygen concentrations would prevent

facilities from being able to use the 20 ppmv outlet concentration compliance option. Because at

some point the combination of low VOC/HAP concentration and technology limitations of

control devices makes it impossible to achieve a high percentage reduction (98 percent in the

case of the Polymers NSPS), the 20 ppmv outlet concentration may be the only compliance

option for some streams. As a result of considering these comments, the final rule for the

Polymer NSPS was changed to require a correction to 3 percent oxygen only if supplemental air

was used to combust emissions.
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Other available information indicates that for some pharmaceuticals processes, dilution is

needed for safety or design considerations other than for use as supplemental combustion air. 

Typically, this dilution occurs in manifolds conveying emission streams from unit operations that

already have high oxygen concentrations, and it occurs for control devices other than

incinerators. Although EPA does not have similar information for the PAI production industry,

the information from the surveyed plants supports the commenters contention that there are

process vent streams with high oxygen concentrations. It is also possible that some of these

streams are diluted for reasons other than to supply supplemental combustion air.

It is not EPA’s intent to prohibit the introduction of dilution air or other gases, only to

ensure that outlet concentrations are corrected for such dilution. As a result, EPA made a

number of changes in the requirement to correct outlet concentrations to prevent dilution. First, a

definition of “supplemental gases” has been added to the final rule; this term includes any

nonaffected streams that contain less than 20 ppmv TOC and less than 20 ppmv HCl/Cl2 that are

combined with affected streams. Second, the final rule clarifies that the correction to 3 percent

oxygen applies only for incinerators, and only if supplemental gases are added. Third, the final

rule explicitly describes procedures to correct for dilution in noncombustion devices.

Comment 4: Three commenters addressed the issue of compliance procedures when the

control device is in compliance with RCRA provisions. Commenter IV-D-27 believes the rule

should specifically state that test methods and compliance provisions under RCRA can be

followed instead of the corresponding provisions in this rule for air emissions and/or wastewater

routed to RCRA incinerators covered under 40 CFR part 264, subpart O or 40 CFR part 265,

subpart O (40 CFR 264/265 subpart O). Commenter IV-D-16 echoed this position for

wastewater and associated residuals and air emissions. According to commenter IV-D-27, this

change would avoid overlapping or contradictory requirements. Commenter IV-D-16 requested

the change because the cross-referenced sections of the HON provide exemptions from

performance testing for other types of units (e.g., BIFs), but do not mention RCRA incinerators. 

Commenter IV-G-05 asked if an affected source that conducts a trial burn to demonstrate

compliance with RCRA regulations can use this same demonstration to comply with the

performance testing requirements of the PAI NESHAP.
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Response: Under the proposed rule, the owner or operator would be exempt from the

requirement to conduct performance tests to demonstrate compliance with the process vent and

storage tank standards if the emission streams are vented to a RCRA control device. 

Specifically, the exemption would apply for hazardous waste incinerators subject to subpart O

and boilers and process heaters subject to subpart H. The cross-referenced wastewater provisions

in § 63.138(h) of the HON would exempt an owner or operator from design evaluation and

performance test requirements (as well as monitoring requirements, and associated recordkeeping

and reporting requirements) for wastewater and residuals treated in RCRA incinerators, boilers,

process heaters, and underground injection wells. In addition, cross-referenced provisions for

wastewater vent streams in § 63.139(d)(4) of the HON are identical to the provisions described

above for process vents and storage tanks, except that they exempt the owner or operator from

design evaluations as well as the performance test requirements.

All of the provisions in the proposed rule have been retained in the final rule. In addition,

to be consistent with other standards, the final rule exempts an owner or operator from all initial

compliance requirements (i.e., emission calculations and design evaluations as well as

performance tests) for process vents and storage tank vents controlled by a RCRA unit. After

making this change, EPA believes that the initial compliance provisions in the final rule are

consistent with the concepts requested by the commenters. Similar comments for monitoring,

recordkeeping, and reporting provisions are discussed in sections 16.10, 17.8, and 18.8,

respectively.

Comment 5: If a facility is using a combustion control device that is capable of burning

liquids, commenters IV-D-21 and IV-D-29 recommended that EPA allow initial compliance

demonstrations based on a metered liquid performance test. According to the commenters, this

approach would be more consistent with the data provided by the industry in response to the

section 114 information request and used to develop the MACT floor. They also note that it

would be a way to streamline the compliance process at lower cost to the facilities.

Response: The EPA rejects the commenters suggestion. The final rule requires that

testing be conducted under the most challenging conditions for the control device, which are

intended to be either the highest hourly HAP load (in vapor phase), or, if the most challenging
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condition is not defined by load, other challenging conditions (such as component solubility for

liquid scrubbers or affinity for carbon). Unless the owner or operator can demonstrate that a test

conducted under conditions in which liquid waste is metered represents the most challenging

conditions for a control device, it may not be used for a compliance determination.

A metered liquid test would not be consistent with the MACT floor determination. As

for many standards, the MACT floor was determined based on reported control efficiencies from

surveyed facilities in the industry. The surveyed facilities based reported control efficiencies on

a variety of information. At most, the reported process vent control efficiencies for only two

processes at one facility were based on the results of a metered liquid test. These reported values

were comparable with those for hazardous waste destruction efficiencies in a RCRA incinerator. 

However, for the MACT floor analysis, EPA considered the efficiencies to be only 98 percent. 

Based on historical data, this is a typical value for a well designed and operated

combustion-based control device. Even if this value is still high, it would be only slightly high,

and the difference would not affect the MACT floor determination.

15.2 INITIAL COMPLIANCE WITH PROCESS VENT STANDARDS

15.2.1 Emission Estimation Calculations

Status at Proposal: The proposed rule included equations for calculating emissions from

five types of emissions episodes: vapor displacement, purging, heating, depressurization, and

vacuum systems. Alternatively, if the owner or operator could demonstrate that the proposed

methods were inappropriate, the proposed rule specified that an owner or operator conduct an

engineering assessment to estimate emissions. The proposed rule stated that the specified

equations would be considered inappropriate if either of two criteria are met: (1) if available test

data and the estimated value differ by more than 20 percent, or (2) the owner or operator

developed any other means to show the equations are not appropriate for a given batch emissions

episode. 

Comment 1: One commenter (IV-D-14) believes facilities should be allowed to calculate

emissions based on all available information, including, but not limited to, the equations in the

proposed rule, and they should not have to demonstrate that the equations in the rule are

inappropriate. According to the commenter, it is not logical to require facilities that produce a
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variety of products, only a small portion of which are PAI’s, to modify their calculation

methodology; nor is it logical to require recalculation on a large scale when the existing

emissions estimates are based on fundamentally sound principles. The commenter also noted

that facilities may already have invested significant resources to develop methodologies for

calculating emissions.

Another commenter (IV-D-28) had several comments on the provisions for estimating

emissions if the emission estimation equations are inappropriate. First, the commenter requests

clarification of the statement that specifies the emission estimation equations shall be considered

inappropriate if certain criteria are met because it could have several interpretations. For

example, the commenter suggested it could mean “not applicable for any one equation,” “not met

for any equation at all,” or “not met for every equation at the same time.” Second, the

commenter supports the provision that allows any method of demonstrating the emission

estimation equations are inappropriate. Finally, the commenter noted that the concept that the

emissions estimation equations are inappropriate if there is a greater than 20 percent discrepancy

between a test value and the calculated value was also used in the P&R I and P&R IV rules,

which are in litigation. If the litigation results in changes to this concept, the commenter believes

EPA should take comment on incorporating the same changes into this rule.

Response: For the final rule EPA did not change the requirement to use equations to

estimate emissions when the emission episodes fit the descriptions provided in the rule. The

EPA believes that the equations in the rule are the most appropriate methods to estimate

emissions from seven specific types of emission episodes. The requirement to use the equations,

when appropriate, also is important in standardizing compliance procedures for the industry and

in providing replicable procedures which the regulated community and EPA can follow to assure

compliance. However, the rule also allows owners or operators to request approval to use

alternatives for estimating emissions. The EPA believes it is important that the owner or

operator be able to make a case for any alternative approach. Finally, as noted in the response to

comment 1 in section 15.1, there are situations where uncontrolled emissions do not have to be

estimated.
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To clarify when an engineering assessment must be conducted and when it may be

conducted, § 63.1365(c)(2)(ii) of the final rule has been changed to read as follows:

(ii) Engineering assessments. The owner or operator shall conduct an engineering

assessment to determine uncontrolled HAP emissions for each emission episode that is not due to

vapor displacement, purging, heating, depressurization, vacuum operations, gas evolution, or air

drying. For a given emission episode caused by any one of these seven types of activities, the

owner or operator also may request approval to determine uncontrolled HAP emissions based on

an engineering assessment. All data, assumptions, and procedures used in an engineering

assessment shall be documented in the Precompliance plan in accordance with § 63.1367(b). An

engineering assessment includes, but is not limited to, the information and procedures described

in paragraphs (c)(2)(ii)(A) through (D) of this section.

(A) Test results, provided the tests are representative of current operating practices at the

process unit. If test data show a greater than 20 percent discrepancy between the test value and

the estimated value, the owner or operator may estimate emissions based on the test data; the

results of the engineering assessment shall be included in the Notification of Compliance Status

report, not the Precompliance plan.

The information and procedures in subparagraphs (B) through (D) are the same as in the

proposed rule. (Note that equations for gas evolution and air drying have been added since

proposal. Also, the second criterion from the proposed rule has been deleted from the final rule

because it is redundant. Note that nothing in the rule prohibits an owner or operator from

requesting approval for any alternative method, but only the 20 percent discrepancy criterion is

“preapproved.”) Following a decision concerning the litigation on other rules that contain the

concept that test data may be used if there is more than a 20 percent discrepancy between a test

value and a calculated value, EPA will determine if any changes to the final rule are necessary

and determine the procedure for implementing any such changes.

Comment 2: Commenter IV-D-28 requested clarification of the requirements for

calculating emissions from vacuum systems. The proposed rule states that emissions from

vacuum systems “may be calculated if the air leakage rate is known or can be approximated,

using Equation 11.” According to the commenter, this could be interpreted to mean that

emissions from vacuum systems do not have to be calculated, but if that is true, it is not clear

what would be required. The commenter also asked what an owner or operator is supposed to do

if the air leakage rate is not known or cannot be approximated.
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Response: For the final rule this provision has been simplified to state that “emissions

from vacuum systems shall be calculated using Equation 24.” The revised statement is more

consistent with the statements associated with equations for the other types of emission episodes.

The owner or operator is responsible for determining how to estimate the value for this variable,

just as the owner or operator is responsible for determining the temperature or volume to use in

other equations.

Comment 3: For purge streams with flow rates greater than 100 scfm,

commenter IV-D-28 believes an owner or operator should not be required to assume the mole

fraction is 25 percent of the saturated value if they have data or have conducted an engineering

assessment to support another value. The commenter also recommended that EPA consider

adding an assumed value (and allow the use of test data or engineering assessments) for

situations where the purge is beneath the liquid level; below the contact area of a scrubber,

absorber, or distillation column; or another location with sufficient liquid/vapor contact.

Response: The proposed and final rules acknowledge that emission episodes may arise

that are not covered by the equations provided in the rule or where the assumptions used to

develop the equations do not apply. Under these circumstances the rule allows the owner or

operator to calculate uncontrolled emissions by conducting an engineering assessment. For

example, if an owner or operator has information to support a different mole fraction than the

default of 25 percent, the owner or operator may submit an engineering assessment in the

Precompliance plan requesting approval to use the alternative value. The Agency decided not to

include an equation for the sparging situations described by the commenter because these are

likely to be site-specific events that do not easily lend themselves to a generalized equation. 

Comment 4: Commenter IV-D-28 believes EPA needs to clarify the procedures for

demonstrating compliance when PAI and non-PAI emissions are combined prior to control. If

the PAI contribution to the combined emission streams entering a control device is small, the

commenter wants to know how to demonstrate that the control device achieves the required

reduction for the HAP from the PAI process, not the other process(es). To address this issue, the

commenter suggested adding provisions similar to those in the distillation NSPS (subpart NNN). 

As a related point, the commenter stated that the rule should specify how to determine the
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uncontrolled emissions if PAI and non-PAI emissions are combined prior to the final recovery

device.

Response: The distillation NSPS specifies procedures for establishing sampling sites and

determining outlet emissions when both nondistillation and distillation vent streams are

combined before a recovery device. There are two inlet sampling sites–one in the distillation

vent stream prior to the combination and the second in the combined stream. The concentration

at the second site is used with the outlet concentration to determine the efficiency of the recovery

device. This value is applied to the concentration from the sampling site in the distillation vent

stream to determine the outlet emissions associated with that specific stream.

Under the proposed rule, the owner or operator would demonstrate compliance with the

percent reduction format of the standard by first using the specified equations or an engineering

assessment to determine the uncontrolled emissions from each emission episode. These values

are equivalent to the emissions based on testing at the sampling site in the distillation vent stream

under subpart NNN. For large control devices, the owner or operator would then determine the

efficiency based on testing at the inlet and outlet of the control device. The “inlet” in this case

would be after all streams to be controlled are combined. Thus, if streams are mixed before a

control device, the performance of the device is evaluated over the mixture. The resulting

efficiency, which is based on the most challenging conditions, regardless of whether they are due

to the PAI vent stream or other vent streams, would then be applied to the uncontrolled emissions

from individual emission episodes to determine the outlet emissions associated with those

episodes. Although the language in the proposed rule differed from subpart NNN, EPA believes

the effect is the same. Therefore, the procedures in the proposed rule have been retained in the

final rule.

The concept of recovery devices for process vent streams has been deleted from the final

rule; the reasons for this change are described in responses to the comment in section 3.4 and the

response to comment 4 in section 5.2. As a result, estimating uncontrolled emissions prior to a

recovery device is not an issue under the final rule. The final rule does retain the concept of

process condensers. However, by definition, a process condenser is an integral part of a process,

which means it would not receive combined streams from multiple processes.
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15.2.2 Compliance with Outlet TOC Limit

Comment 1: Three commenters (IV-D-16, IV-D-27, and IV-D-28) believe EPA should

justify why a performance test to demonstrate compliance with the outlet TOC concentration

under § 63.1364(c)(1)(viii) of the proposed rule must be conducted only under absolute

peak-case conditions. Commenters IV-D-27 and IV-D-28 also believe this section unnecessarily

restricts the choice of test methods that may be used to demonstrate compliance with the outlet

TOC concentration. Both commenters requested that this section be modified to allow

combinations of test methods to measure TOC, consistent with § 63.1364(b)(6). 

Commenter IV-D-27 also requested that this section be modified to allow measurement of total

organic HAP using Method 18.

Response: The final rule has been modified to include two options for demonstrating

compliance with the outlet TOC concentration: (1) continuously monitor outlet concentration

using an FID or other device; or(2) perform an initial performance test at absolute or hypothetical

peak-case conditions and continuously monitor operating parameter levels to demonstrate

continuous compliance with outlet TOC concentration. Initial testing at the absolute or

hypothetical peak-case conditions is not necessary for Option 1 because continuous compliance

is determined through the use of an FID or other device that continuously monitors outlet

concentration (however, if the monitor is to be calibrated on the predominant HAP, it may be

necessary to perform an initial test to identify the HAP). Conversely, EPA believes testing under

the absolute or hypothetical peak-case conditions is necessary for the second option to ensure that

operating parameter levels are established that will ensure compliance under all operating

conditions. The monitoring requirements for Option 2 are the same as the monitoring

requirements for complying with the percentage reduction format of the standard. Therefore,

EPA believes the initial testing that is used to establish the monitoring parameters should also be

the same in both cases.

Finally, EPA has modified the final rule so as not to restrict the choice of methods that

the owner or operator may use to determine TOC (i.e., Method 18 is allowed for speciation). 

However, EPA emphasizes that the concentration limit is based only on TOC, not total organic

HAP.
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15.2.3 Exemption from Performance Testing

Comment 1: The provisions in §§ 63.1364(c)(5)(i) and (d)(5)(iii) of the proposed rule

would exempt a facility from the requirement to conduct a performance test if a previous test was

conducted using the same procedures. Three commenters (IV-D-21, IV-D-28, and IV-D-29)

believe these provisions are useless because it is unlikely that a previous performance test would

have been conducted using the same procedures and under the same peak-case conditions. 

Commenter IV-D-28 believes that any test conducted on the subject control device to

demonstrate compliance under any EPA-supervised program (e.g., NSPS, NESHAP, RCRA, new

source review) should be sufficient to demonstrate compliance with this regulation. 

Furthermore, this commenter stated that a shared control device should not be subject to multiple

compliance demonstrations; one should be sufficient to show compliance with all standards. 

Commenter IV-D-29 suggested adding another option in § 63.1364(b)(11)(ii) which provides for

an alternative site-specific test and/or design evaluation plan developed by the company for the

following situations: (1) when batch process units share common abatement with continuous

process units (because batch emissions cannot be separated from continuous emissions), (2) for

batch processes which campaign different products with different HAP that use the same

equipment (perhaps even with years between production runs), or (3) for batch processes which

have unique circumstances where the prescribed methods in § 63.1364(b)(11)(ii)(A) through (C)

are not feasible.

Response: The Agency maintains that performance testing under peak-case conditions is

necessary to ensure compliance over a range of conditions, especially when variability in

emission stream characteristics cannot be predetermined. If a test was not conducted under the

specified peak-case conditions, it does not provide assurance that the required level of control

can be met under such situations.

The EPA also is not convinced that there are circumstances under which it would be

necessary to allow an alternative to testing under peak-case conditions. As noted in section 14.1

of this document, the final rule allows testing under absolute or hypothetical peak-case

conditions, and these conditions are established based on an emissions profile. The final rule

also provides several options for developing the emissions profile. The goal is to identify the
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most challenging conditions that the control device will encounter, regardless of the emissions

source. Thus, manifolding batch and continuous process vents is acceptable; the batch emissions

do not have to be evaluated separately. Also, the approach can accommodate different batch

processes operating at different times with different HAP. Even if the owner or operator

determines that the most challenging conditions only occur for a process that is run infrequently

and at a time that is not convenient for testing, the owner or operator may simulate conditions for

the test that are similar to (or more challenging than) the actual most challenging conditions (i.e.,

test under hypothetical peak-case conditions). Thus, the final rule was not changed to

incorporate the commenters suggestions.

Comment 2: Commenter IV-D-28 supports the provision that allows initial compliance

demonstrations for small control devices to be based on design evaluations, but three

commenters (IV-D-14, IV-D-16, and IV-D-27) requested changes in the cutoff that defines the

minimum size of a control device for which a performance test must be conducted to

demonstrate compliance. Commenters IV-D-16 and IV-D-27 recommended that the cutoff be

changed from “greater than 10 ton/yr of HAP” to “greater than 10 ton/yr of any individual HAP

or greater than 25 ton/yr of aggregated HAP” because this would be consistent with rationale in

the Basis and Purpose document, which is that this criterion is based on the application of the

major source cutoffs. These two commenters also believe the rule should be clarified to indicate

that the cutoffs are for the class of pollutant for which the performance test is being conducted

(i.e., organic HAP or HCl/Cl2); this clarification is needed to avoid the situation where a

performance test would be required to demonstrate control of a negligible amount of organic

HAP simply because the quantity of HCl present is above the cutoff. Commenter IV-D-14

believes the proposed cutoff should apply only to HAP emissions from PAI processes if the

control device is used to control emissions from both PAI processes and other types of processes.

Response: The EPA continues to believe that the testing cutoff for control devices is

proper. In developing the regulation, EPA could have required testing for all control devices. 

However, EPA proposed the testing cutoff to decrease the testing burden on the industry. For

devices handling lesser loads, EPA believes that the design evaluation will be adequate to

demonstrate compliance.
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The applicability cutoff for performance testing applies to the inlet stream to the control

device, regardless of the amount from PAI manufacturing contributing to the total emissions or

the type of HAP (i.e., organic HAP or HCl/Cl ) . The intent of the cutoff is to identify larger 2

emissions sources where PAI and other emission occur, not only what is emitted from the source

category. However, if both organic HAP and HCl/Cl emissions are vented to a control device, 2

the owner or operator is only required to conduct a performance test for the class of pollutant that

the control device is being used to control. To clarify this point, the final rule states that the

owner or operator may assume the control efficiency of HCl/Cl to be zero percent if the control 2

device is intended to reduce only organic emissions and vice versa.

15.2.4 Provisions for Flares

Comment: Section 63.1364(c)(4)(v) of the proposed rule would exempt an owner or

operator from an initial compliance test for a flare that complies with the criteria in § 63.11(b) of

the General Provisions. Commenter IV-D-28 questioned whether this provision requires an

initial compliance demonstration when the control device is a flare. According to the

commenter, this provision could be interpreted to mean that if the flare ever fails to meet the

criteria in § 63.11(b) that a performance test would have been required for initial compliance,

which would not be appropriate for flares anytime, and also would be an unfair retroactive

violation. The commenter notes that this provision also refers to the performance criteria for a

flare in the General Provisions. However, the commenter believes the General Provisions do not

require a compliance demonstration; therefore, that requirement needs to be stated in this

regulation. If it is required, the commenter recommends adding a new paragraph to the

section on testing provisions in the rule instead of revising paragraph (c)(4)(v) because a flare

could be used to control more than process vents. It should require an owner or operator to

demonstrate compliance by passing a visible emissions test and determining the exit velocity and

net heating value using the appropriate procedures from § 63.11(b).

Response: The Agency agrees with the commenter that § 63.11(b) is not clear on whether

an initial compliance demonstration is required. In response, the Agency has revised the final

rule to clearly state that Test Method 22 in appendix A of 40 CFR part 60 shall be used to
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determine opacity, Test Method 18 in appendix A of 40 CFR part 60 shall be used to ensure the

proper heating value of the gas being combusted, and Method 2, 2A, 2C, or 2D of appendix A of

40 CFR part 60 shall be used to determine exit velocity. The EPA also agrees with the

commenter that the provisions should not be limited to flares used for process vent emissions. 

As a result, paragraph (c)(4)(v) in the proposed rule has been replaced with revised provisions in

an introductory paragraph in § 63.1365 so that they are applicable to all flares.

15.2.5 Provisions for Condensers

Comment: Commenter IV-D-28 believes the rule should allow an owner or operator the

option to demonstrate compliance for a condenser using either the temperature measurement

option or a performance test. According to the commenter, the temperature measurement option

is beneficial because it may reduce the compliance burden in some cases, but the traditional

testing method is also needed because the temperature measurement method may result in false

determination of noncompliance and is not necessarily always less burdensome.

Response: Under the proposed rule, EPA included three options for sources to determine

emissions and control efficiencies for condensers: (1) performance testing including

measurement of HAP concentration and flowrate under peak-case conditions, (2) direct

measurement of temperature of the outlet gas under peak-case conditions, or (3) emission

estimation. Since proposal, EPA identified the following problems with the proposed options: 

(1) direct measurement of temperature is a procedure to demonstrate ongoing compliance, not

initial compliance; (2) for condensers, determining the control efficiency during the peak-case

conditions does not ensure that the same or higher control efficiencies will be achieved under

other conditions; (3) options 2 and 3 are not independent because the outlet temperature is

needed to estimate emissions from a condenser; and (4) performance testing is not a replicable

procedure for batch processing operations and is unnecessary for establishing the control

efficiency. To address these concerns, the final rule was revised to include only one procedure

for demonstrating initial compliance when using a condenser. This procedure requires

calculation of the outlet temperature that is needed to achieve the required control efficiency for

an emission episode (or group of episodes).
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Determining the control efficiency for condensers under the peak-case conditions does

not ensure that the control efficiency under other conditions will be the same or higher. Under

the proposed rule, the peak-case conditions were defined based on the stream from which the

maximum amount of heat must be removed over a specified time period to achieve the required

emissions reduction. However, to achieve the required control efficiency for another emission

stream with a different pollutant and/or temperature may require a significantly lower outlet

temperature, even though less heat is removed. Basing the monitoring on the temperature for the

stream with the maximum heat removal requirement would not ensure that the lower outlet

temperature could be achieved for the other stream.

The revised procedure for the final rule is a replicable protocol in that for identical inlet

conditions, every source will estimate the same controlled emissions and control efficiency when

using the same outlet temperature. Performance testing for batch processing operations, on the

other hand, can be difficult and can lead to considerable variability in results. In addition to

concerns about replicable results, the performance testing provisions in the proposed rule were

not structured to properly account for control efficiency of condensers under all conditions. 

Under the performance testing option in the proposed rule, the control efficiency would be

determined for the peak-case conditions. Then, using the heat removal rate that occurred during

the test, the outlet temperatures, and thus control efficiencies, could be calculated for other inlet

conditions. However, a performance test is not needed because these temperatures can be

calculated based on the properties of the emission streams. For these reasons, the final rule does

not specifically require testing of condensers (e.g., measurement of flowrate and concentration to

generate a mass rate) as a means of compliance with the standards. However, as with other

practices, owners and operators can propose alternative means of demonstrating compliance with

the standards for approval on a case-by-case basis. 15.2.6 Provisions for Thermal Incinerators

Comment: Commenters IV-D-16 and IV-D-27 requested that EPA justify the provision

that restricts the maximum allowable flowrate into a thermal incinerator to design values if

testing is conducted under representative peak conditions. Commenter IV-D-28 believes this

provision is meaningless for control devices that are designed with excess capacity, which is

what the commenter typically does.
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Response: The final rule specifies that performance testing shall be conducted under

peak-case conditions for all control devices. As discussed in the responses to comments in

section 14.1, the language allowing for testing of incinerators under representative peak-case

conditions has been deleted because of Agency concerns regarding operation at levels higher than

the levels under which the compliance demonstration occurred. Therefore, the requirement to

restrict maximum allowable flowrate into the incinerator is no longer necessary and has been

deleted from the final rule.

15.2.7 Clarifications

Comment: Commenter IV-D-28 requested each of the following editorial clarifications in

§ 63.1364(c) of the proposed rule. The first sentence in paragraph (c)(1) should cross-reference

the exemptions in paragraph (c)(5) as well as those in paragraph (c)(4). The second sentence in

paragraph (c)(1)(ii) should mention the 94 and 99.9 percent reduction requirement for HCl as

well as the corresponding emission limit cutoffs of 6.8 and 191 Mg/yr. 

Paragraphs (c)(2)(i)(A)(3) through (5) should be revised to state that the owner or operator is to

determine HAP partial pressures in accordance with one of the following subparagraphs; as

written it sounds like all three must be used simultaneously. In the variables list for Equation 3,

the definitions of T1 and T2 should refer to the temperature of the material in the vessel, not to

the temperature of the vessel itself. Paragraph (c)(3)(ii) describes control devices that “meet” an

outlet concentration of 20 ppmv, but it should say “are intended to meet.” Paragraph (c)(3)(ii)(B)

requires sampling for oxygen and TOC at the same time; however, it would be better to require

the sampling at “substantially” the same time because there will always be slight differences

between the starting (or ending) times of the two samples, which should not be considered

violations. Paragraphs (c)(3)(iii)(B), (C), and (D) indicate that an owner or operator may “also”

choose to test over representative peak-case conditions, but this suggests that two tests would be

conducted; these paragraphs should say testing under representative peak-case conditions is an

alternative to testing under absolute or hypothetical peak-case conditions. 

Response: The percent reduction requirements for HCl were specified in

paragraph (c)(1)(iv) of the proposed rule. However, the Agency agrees that this provision and

most of the other provisions identified by the commenter need to be clarified. Some of the
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suggested changes have been incorporated verbatim into the final rule. In other cases, more

substantial changes to provisions make it impossible to incorporate the suggested changes

verbatim. For example, as noted elsewhere in this document, the final rule does not allow testing

under representative peak-case conditions. However, for the provisions that have been retained

in the final rule, the intent of each suggested change has been incorporated. The final rule has

not been changed to specify that sampling for oxygen and TOC is to be conducted at

“substantially” the same time because other rules do not use this qualifier. Also, slight

differences in sampling time are to be expected, and are not considered violations.

15.3 INITIAL COMPLIANCE WITH STORAGE TANK STANDARDS

Comment 1: If an owner or operator uses a floating roof to comply with the storage tank

standards, paragraph (d)(4) in § 63.1364 of the proposed rule would require the owner or

operator to demonstrate initial compliance by complying with various provisions in §§ 63.119

and 63.120 of the HON. Commenter IV-D-28 believes a sentence should be added to the end of

§ 63.1364(d)(4) to indicate that compliance with the provisions of this section (i.e., the

cross-reference to floating roof provisions in the HON) shall be deemed to constitute compliance

with the percentage HAP emission requirements of this subpart.

Response: The EPA disagrees with the commenter’s suggestion. The standard is to

install either a floating roof or a closed vent system with a control device. Thus, installing a

floating roof in accordance with provisions in the regulation demonstrates compliance with the

standard; it is not a means of demonstrating compliance with the percent reduction standard.

Comment 2: Paragraphs (d)(2)(iii) and (iv) in § 63.1364 of the proposed rule would

exempt sources from performance test requirements for storage vessel control devices if either: 

(1) the control device is also used to control process vent emissions and the owner or operator

demonstrates initial compliance with the process vent standard, or (2) the control device is a

RCRA unit or a boiler or process heater that meets certain criteria. Commenter IV-D-28 believes

the following sentence should be added to the end of both paragraphs: “This constitutes

compliance for the purposes of this subpart.”

Response: The Agency believes the sentence the commenter wants to add to the rule is

either unnecessary or incorrect, depending on the meaning the commenter intended. For
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example, the commenter may want to clarify that compliance with either of the subject

provisions constitutes initial compliance. However, EPA believes the additional sentence is

unnecessary for this purpose because an introductory sentence in the section that contains these

provisions clearly states that the owner or operator demonstrates initial compliance by fulfilling

the requirements of either of the subject paragraphs. Alternatively, the commenter may want

EPA to specify that compliance with the subject paragraphs constitutes compliance with all

provisions of the subpart. The EPA believes this would be confusing because § 63.1365 deals

only with initial compliance provisions, and it would be incorrect because other regulatory

requirements still apply to the control devices (although not specifically to the control of

emissions from the storage vessels). The commenter may believe the statement is needed to

ensure that an owner or operator is not subject to duplicative monitoring, recordkeeping, and

reporting requirements for multi-use control devices. However, the monitoring, recordkeeping,

and reporting provisions in §§ 63.1366 through 63.1368 focus on individual control devices, not

the type(s) of emission points venting to the device, and § 63.1362(l) of the final rule exempts

RCRA incinerators and boilers from the initial compliance, monitoring, and recordkeeping

requirements of the final rule. In addition, monitoring is not required for the subject boilers and

process heaters. Finally, the commenter may be concerned that the subject paragraphs exempt

the owner or operator from only performance tests, but not design evaluations. For the final rule,

a number of changes have been made in § 63.1365, one of which was to clarify that the

exemptions apply to all initial compliance demonstrations for affected storage vessels (i.e., to

design evaluations as well as performance tests). Therefore, EPA did not add the sentence that

the commenter suggested.

Comment 3: Commenters IV-D-21 and IV-D-29 found the compliance procedures for

new Group 1 storage tanks to be unnecessarily convoluted. The commenters requested

confirmation of their interpretation that the provisions mean a design evaluation may be used to

demonstrate compliance.

Response: The commenters are correct; initial compliance with the standards for storage

tanks at new sources may be demonstrated using either a design evaluation or a performance test. 

For the final rule, § 63.1365 has been reorganized and edited to clarify numerous provisions,

including the one cited by the commenter.
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15.4 INITIAL COMPLIANCE WITH WASTEWATER STANDARDS

Comment: Commenter IV-D-28 stated that section 63.1364(e) of the proposed rule is

unclear because it says to “demonstrate compliance” with the wastewater requirements by

“complying” with the wastewater requirements. The commenter suggested that this

section should say compliance should be demonstrated by complying with the applicable

provisions of § 63.145.

Response: The Agency agrees with the commenter that the language in § 63.1364(e) of

the proposed rule is unclear; therefore, the suggested change has been incorporated into the final

rule.

15.5 PLANNED ROUTINE MAINTENANCE

Comment: The proposed rule specified that an owner or operator would demonstrate

compliance with the planned routine maintenance provisions by including the periods of planned

routine maintenance in each Periodic report. Commenter IV-D-28 requested clarification of

whether facilities are to report anticipated (planned) numbers, actual (as happened) numbers, or

both.

Response: As noted in the response to the comment in section 6.4, the planned routine

maintenance provisions in the final rule only apply to storage tanks. Section 63.1365(d)(7) of the

final rule specifies that an owner or operator demonstrates initial compliance with these

provisions by reporting in the NOCS report the anticipated periods of planned routine

maintenance for the first reporting period (i.e., the 6 months after the NOCS report is due). 

Ongoing compliance is demonstrated by including both the actual hours for the previous

reporting period and anticipated hours for the next period in each Periodic report. The sum of the

actual hours in the previous 12 months must be less than 240 hours for the facility to be in

compliance. The reports also must describe the type of maintenance to be performed and that

was performed. These provisions are similar to the provisions in §§ 63.120(d)(4) and

63.122(g)(1) of the HON.
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16.0 MONITORING

16.1 IMPACT OF MONITORING REQUIREMENTS ON CONTROL LEVELS

Comment: Several commenters (IV-D-16, IV-D-20, and IV-D-27) believe that the

requirement to set compliance parameter levels based on performance testing at peak conditions

for batch processes will result in significant over control during most of the operation. 

Commenters IV-D-16 and IV-D-20 indicated that the following requirements also increase the

stringency: (1) using the average of three test runs for setting parameter limits, and

(2) determining compliance on a daily basis. Commenters IV-D-16 and IV-D-27 suggested that

the impact could be minimized by not restricting the length of the test runs and by calculating

compliance on an annual basis rather than daily. The commenters suggested an annual basis

because they believe the data provided in response to the section 114 information request were

based on annual averages. Commenter IV-D-27 suggested daily calculations of rolling annual

averages, and commenter IV-D-16 suggested monthly calculations of rolling annual averages. 

Another commenter (IV-D-28) supports the proposed provisions to base compliance on the daily

average of parameter values, not each individual monitored data point.

Response: As noted in the responses in sections 7.4 and 8.3, EPA believes the data

provided in response to the survey are as valid on a daily basis as on an annual basis. Testing for

initial compliance determinations may be as short as three 1-hour runs. In such cases, the

regulation could require that continued compliance be demonstrated using hourly average

monitoring parameter levels to be consistent with the data from the initial compliance

determination. The proposed rule would require a less stringent approach of averaging over an

operating day because EPA believes this minimizes the impact of momentary disruptions and

variability, yet also gives a reasonable assurance of continued compliance with the standard. 
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Therefore, the final rule retains the requirement to demonstrate continued compliance with the

standard on a daily basis.

In the final rule, EPA requires that testing be conducted under absolute or hypothetical

peak-case conditions for all control devices because EPA firmly believes that if the conditions

under which the device will be operatedcannot be predetermined, the device must be

demonstrated to achieve the required efficiency over peak-case conditions. If inlet stream

conditions can be predetermined, the owner or operator has the option of setting multiple

monitoring levels for different operating conditions. This option was provided in the proposed

rule and has been retained in the final rule. Therefore, EPA does not believe the requirement

results in over control. Also, as noted in section 14.4, the final rule has been changed to remove

the provision restricting test runs to no more than 8 hours.

Regarding averaging periods, EPA has modified the compliance period of the standard to

allow averaging on either a 24-hour basis or a “block” basis, where the block may be any length

of time less than the time from the beginning to the end of a batch process. For batch operations,

an annual compliance period was determined by EPA to be too difficult to implement and

therefore not practical. The annual compliance period implies that owners and operators could

control a process to varying degrees during the course of a year, as long as the yearly percent

reduction target would be met. Although this format would offer flexibility to owners and

operators who want to change control strategies to accommodate production scheduling and

operational changes, EPA believes that the demonstration of compliance over such an extended

time period would result in delayed determination of exceedances and the possibility for

extended periods of violations. The EPA notes that the final rule offers numerous compliance

options to provide flexibility for owners and operators to address variability within their

processes. 

Regarding the setting of parameter levels, the purpose of monitoring operating parameters

is to provide evidence of continued compliance with the rule. Monitoring parameters are set

based on test data, calculations, or information from the evaluation of the control device design.

The final rule requires sources to establish maximum or minimum operating parameter levels

based on the average of the average parameter values for each of the three test runs (i.e., average
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values are to be determined for each of the three test runs, and the monitoring parameter level is

to be based on the average of those three values). The Agency believes that setting monitoring

levels based on the average of three test runs is necessary because the control efficiency is also

based on the average from the three test runs. Basing the monitoring parameter on the results of

only one of the test runs would be inconsistent with the average control level.

16.2 ESTABLISHING PARAMETER LEVELS

Comment 1: Commenter IV-D-28 found it difficult to determine when parameter limits

are to be determined based on performance tests and when other methods may be used. For

example, the commenter believes § 63.1365(a) of the proposed rule could be interpreted to mean

every parameter limit has to be based on a performance test, even though a test may not have

been conducted to demonstrate initial compliance. The commenter urged EPA to clarify these

provisions using language similar to that in previous MACT standards (e.g., the Group I and

Group IV P&R rules).

Response: One sentence in § 63.1365(a) of the proposed rule stated that “test data,

calculations, or information from evaluation of the control device design shall be used to

establish the operating parameter.” Another sentence specified how to establish the parameter

level if performance testing has been required. The intent of these statements was to indicate that

monitoring parameter levels are to be established during the initial compliance demonstration. If

the initial compliance demonstration is a performance test, the parameter levels are based on the

operation during the test (although, as noted in another response in this chapter, some levels may

also be based on extrapolation of data obtained during a test). If the initial compliance

demonstration is a design evaluation, the parameter levels are to be based on the design

evaluation. To clarify this requirement, the final rule specifies that monitoring parameter levels

are to be established based on test data, calculations, or other information from the initial

compliance demonstration.

Comment 2: Three commenters (IV-D-16, IV-D-20, and IV-D-28) questioned and

expressed concern about setting monitoring parameter levels based on the average of the values

from three test runs rather than the least stringent value. Commenter IV-D-16 stated that using

the average value to establish the limit is problematic because affected sources would have no
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opportunity to compensate for potential process deviations that occur with the use of multipurpose equipment and other factors that would influence compliance with the measured

parametric levels. Thus, commenter IV-D-16 believes that a source should be able to establish

parameter ranges other than those measured during a performance test. Commenter IV-D-20

believes there is no basis for using the average value because performance testing will always be

biased to indicate a parameter value more than sufficient to achieve compliance.

Response: The EPA disagrees with the commenters. The least stringent monitoring

parameter value is not necessarily indicative of conditions needed to demonstrate continued

compliance with the standard, just as demonstrating initial compliance using results from a

performance test with only a single run would not be considered acceptable. This is especially

true under certain situations. For example, to demonstrate compliance with the 90 percent

reduction standard for process vents, a test might yield control efficiencies of 88, 89, and

93 percent. Perhaps the least stringent monitoring parameter level would be associated with the

run that produced the 88 percent control efficiency. Using this least stringent level would not be

consistent with the conditions that were needed to achieve a 90 percent reduction. Furthermore,

if an owner or operator believes the control device will achieve an efficiency well above that

needed to demonstrate compliance, nothing in the rule prohibits the owner or operator from

conducting a test under less than optimum conditions in an effort to minimize the stringency of

the operating parameter level.

The proposed rule also included an error that has been corrected in the final rule. The

proposed rule states that a minimum is to be based on the average of the minimum values from

each of the three test runs, and that a maximum is to be based on the average of the maximum

values from each of the three test runs. The statements should have specified that the minimum

(or maximum) is to be based on the average of the values from each of the three runs (i.e., the

average of the averages for the three runs). This change has been made in the final rule.

Comment 3: Commenter IV-D-16 requested that additional control device parameter

monitoring options be added to the rule (e.g., pH for scrubbers and coolant temperature for

condensers) because the few parameters mandated by the proposed rule would be very expensive

and inappropriate for many sources.
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Response: As suggested by the commenter, pH as a parameter for acid gas scrubbers was

added to the rule. In addition, parameters for catalytic incinerators were added. If an owner or

operator believes it would be appropriate to monitor parameters other than those specified in the

rule, the owner or operator may request approval to monitor other parameters in accordance with

the General Provisions or by using the Precompliance plan. Monitoring the coolant temperature

for condensers was not included in the rule because coolant temperature is not a direct indicator

of condenser efficiency. The EPA believes that, while monitoring coolant flow to ensure

compliance with the standard may be a reasonable alternative for some systems, sources must

demonstrate that the measurement of coolant temperature for each condenser system will achieve

the required outlet gas temperature. This demonstration most likely would involve appropriate

heat transfer calculations and verified condenser (heat exchange) system specifications (i.e., heat

transfer coefficients and heat transfer area) in addition to providing actual temperature

measurements verifying the relationship between coolant temperatures and gas temperatures.

Comment 4: Commenters IV-D-16 and IV-D-27 support the provisions that allow

owners and operators the opportunity to request approval to monitor parameters other than those

specified in the rule (i.e., by following the procedures in § 63.8(f) of the General Provisions or by

using the Precompliance plan). However, commenter IV-D-16 believes that all facilities will use

the Precompliance plan because the procedures in § 63.8(f) are too narrow and restrictive. To

accommodate future changes, commenter IV-D-16 also requested that the rule state that

alternative monitoring parameters can be implemented via amendments to the Precompliance

plan.

Response: The final rule specifies how to request approval to change parameters or

procedures that were submitted for approval in the Precompliance plan, or that would have been

included in the Precompliance plan if the change had been implemented prior to the compliance

date. The new provision requires an owner or operator to submit a notification 60 days before

the scheduled implementation date. The notification must contain the same information that

would have been included in the Precompliance plan.

Comment 5: Commenter IV-D-29 urged EPA to exclude batch processes that vent to a

combustion device or share a common combustion device with continuous processes from
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§ 63.1365(b)(2) of the proposed rule. The commenter explained that this section of the proposed

rule, which specifies the procedures to establish a parameter level, is meaningless for a control

device such as a flare because the monitoring parameter would be the presence of a pilot flame,

which is not related to the characteristics of the vent stream from a single emission episode.

Response: The EPA agrees with the commenter that procedures to establish a parameter

level for flares is not needed because only the presence of a pilot flame is required. The final rule

clarifies this point. However, it is not clear why the commenter requested the elimination of

procedures for monitoring combustion devices that are used to control emissions from batch

processes. Monitoring is as feasible for these devices as for those that control vents from

continuous vents. 

Comment 6: Commenter IV-D-28 requested clarification of the provision in

§ 63.1365(b)(2)(iv) of the proposed rule that monitoring levels be established at the conditions of

the test when the performance test is conducted at “routine” conditions.

Response: Section 63.1365(b)(2)(iv) is an artifact of a draft approach and should not

have been included in the proposed rule. It is not included in the final rule.

Comment 7: The EPA solicited comment on the use of alternative parameters without

the requirement of prior notification in the Precompliance plan. The preamble to the proposed

rule also requested comment on the adequacy of the following alternative parameters: (1) for

condensers, coolant temperature and flow (only with emissions testing); (2) for scrubbers,

pressure drop, scrubber fluid composition or pH; and (3) for carbon adsorbers, adsorption cycle

and regeneration frequency, bed temperature, regeneration stream flow, periodic test for bed

poisoning, and periodic vent testing and/or predetermined scheduled replacement. 

Commenter IV-G-05 believes the suggested alternative parameters are adequate to demonstrate

continuous compliance with the rule. However, the commenter wondered why EPA solicited

comments on the use of alternative parameters without prior notification in the Precompliance

plan when the proposed rule also clearly would require the owner or operator to determine the

most appropriate method of verification and propose this method for approval in the

Precompliance plan.
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Response: The alternatives for scrubbers and carbon adsorbers have been included in the

final rule. However, the alternative for condensers has not been included because, as noted in

section 15.2.5 of this document, EPA has decided that the most appropriate method for

estimating outlet emissions and the percent reduction is to use the results of temperature

measurements, not emissions tests.

Under the proposed rule, the requirement to conduct a periodic verification to

demonstrate that the control device is operating as designed applied only to small control devices

(i.e., those with inlet HAP emissions less than 0.91 Mg/yr). For larger control devices, the

proposed rule specified default parameters to be monitored. If an owner or operator elected to

monitor these parameters, no approval would be necessary. However, an owner or operator

would have to request approval to monitor different parameters, either by including the request in

the Precompliance plan or by following the procedures in § 63.8(f) of the General Provisions. 

This concept is also included in the final rule.

16.3 MONITORING FOR SPECIFIC CONTROL DEVICES

16.3.1 Bag Dumps and Product Dryers

Comment 1: Commenters IV-D-16 and IV-D-28 believe the requirement to initiate

corrective action within 1 hour of a bag dump alarm is unnecessarily rigid and will not always be

necessary. Commenter IV-D-28 believes it is too stringent because: (1) an alarm is

conservatively set so it does not always mean emissions are occurring; (2) there may be times

(especially in batch operations) when an alarm trips even though the system is not currently in

use; (3) there may be other things happening in the process unit that justifiably require priority

attention (e.g., a serious overpressure in the reactor area); and (4) depending on what EPA means

by “initiate,” some corrective actions cannot be initiated within 1 hour (e.g., if a problem occurs

after normal business hours that requires a replacement part that is not on hand at the site). 

Commenter IV-D-16 suggested changing the 1-hour time period to 3 hours.

Response: When an alarm on a bag leak detection system is triggered, the proposed PAI

rule would require owners or operators to inspect the control device to determine the cause of the

deviation and initiate corrective actions specified in the corrective action plan that is submitted

with the Notification of Compliance Status report. The definition of initiate is to be specified by
16-8

the owner or operator in the plan. To clarify this point, the final rule specifies that the owner or

operator is to initiate procedures to identify the cause of the alarm and take correction action as

specified in the corrective action plan. The final rule does not specify the time when these

actions are to be initiated or implemented; the owner or operator should specify that information

as part of the procedures for responses to different types of events that trigger the alarm. The

final rule also specifies that the corrective action plan is to be submitted with the Precompliance

plan, which includes other procedures that must be approved by the implementing agency.

Comment 2: Commenter IV-D-28 believes the rule should allow either visual or audible

bag dump alarms, not just audible alarms.

Response: The Agency believes that both a visual and audible alarm are necessary

because staff may not be in a control room or other areas where visual alarms can be seen. In

addition, this requirement is consistent with other NESHAP requiring leak detection systems; no

changes have been made in the final rule.

Comment 3: Commenter IV-D-28 believes two of the monitoring provisions for bag

dumps and product dryers are unlawful. First, the commenter believes the requirement in

§ 63.1365(a)(7)(iv) of the proposed rule to install, operate, calibrate, and maintain the bag leak

detection system according to either available guidance from EPA or the manufacturer’s written

specifications and instructions is unlawful because EPA cannot impose a legally binding

requirement to follow unspecified “guidance,” and EPA cannot empower manufacturers to make

law. Therefore, the commenter suggested adding a third option to allow the owner or operator to

“follow other written procedures that provide reasonable assurance that the bag leak detection

system will function appropriately.” Second, the commenter believes the requirement in

§ 63.1365(a)(7)(viii) of the proposed rule to develop a QIP consistent with the draft approach to

compliance assurance monitoring is unlawful because EPA cannot require compliance with a

draft document. The commenter believes EPA should either publish a supplemental proposal

specifying the features of an acceptable QIP and make it part of the rule or delete the

requirement.

Response: The EPA has completed guidance entitled “Fabric Filter Bag Leak Detection

Guidance.” This document provides guidance on the use of triboelectric monitors as fabric filter
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leak detection systems. Where this document is not applicable, EPA has allowed for the use of

manufacturer’s written specifications and instructions. Proper setup and operation of a bag leak

detector can vary with site-specific conditions, and those conditions may dictate variances from

EPA guidance or manufacturer’s specifications and instructions. For such cases, EPA has added

a provision that would allow for the development of site specific procedures. These procedures

must be included in the Precompliance plan and approved by the Administrator.

The final rule does not require the development of a QIP program.

Comment 4: Commenter IV-D-28 believes it is both unnecessary and inconsistent with

other aspects of the rule to require written approval before adjusting the range, averaging period,

alarm set points or alarm delay time contained in the Notification of Compliance Status report. 

According to the commenter, the rule should only require that changes be reported in the next

Periodic report, and, if prior approval is needed, it will be handled under the Operating Permit

program.

Response: The intended use of the bag leak detector is to identify upset conditions in the

baghouse operation. The EPA is concerned that unrestricted adjustment of the bag leak detector

could result in improper use, possibly resulting in the alarm and sensitivity settings being set

such that leaks or malfunctions could occur undetected. Based on further review, EPA has

determined that periodic adjustment may be necessary. Therefore, EPA has revised the bag leak

system adjustment requirements to: (1) allow for routine minor adjustments to the detector

system, (2) require owners and operators to identify all routine adjustments in an operating and

maintenance plan that is to be submitted with the Precompliance plan, and (3) require that

owners and operators perform complete baghouse inspections to ensure proper operation of the

baghouse prior to any significant adjustments to the sensitivity or range.

Comment 5: Commenter IV-D-28 asked for clarification of the requirement that a bag

leak detection system sensor must provide output of relative or absolute PM emissions.

Response: The final rule has clarified this statement by requiring that “The bag leak

detection system sensor must provide output relative to PM emissions.” 

16.3.2 Flares
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Comment 1: Commenter IV-D-28 believes §§ 63.1365(a)(5) and (b)(7) of the proposed

rule should refer to the loss of “all” pilot flames, because losing one flame should not be a

violation if there are other flames at the pilot of the flare.

Response: The EPA agrees with the commenter. The final rule indicates that an

exceedance occurs upon the loss of all pilot flames and that records must be kept of periods when

all pilot flames are absent.

Comment 2: Commenters IV-D-21 and IV-D-29 believe the rule should specify that a

pilot flame is not required when a process is shutdown. These commenters also pointed out that

this change would be consistent with the HON.

Response: As noted in the response to the comment in section 16.4 of this chapter, the

final rule specifies that monitoring is only required when the control device is functioning in

achieving the HAP removal required by the rule. Thus, the final rule does not require an owner

or operator to demonstrate the presence of a pilot flame during periods when the process is not

operating. However, while implementing shutdown, the owner or operator must follow the

procedures described in the startup, shutdown, and malfunction plan. These procedures may

specify that the pilot flame be maintained during the shutdown process.

16.4 MONITORING FREQUENCY

Comment: Commenter IV-D-16 suggested two changes to the frequency of monitoring. 

First, the commenter believes that the requirement in § 63.1365(b)(3) of the proposed rule to

monitor batch episodes less than 15 minutes in duration should not be required. Second, the

commenter believes the monitoring frequency is excessive for control devices controlling less

than 10 ton/yr of an individual HAP or 25 ton/yr of aggregate HAP; “periodic” monitoring would

be sufficient because many parameters do not vary frequently, and it would allow for the use of

simpler monitoring systems that are less prone to design and maintenance problems.

Response: When only one monitoring level is established for a parameter, the EPA

agrees with the commenter that monitoring of batch episodes less than 15 minutes in duration

should not be required because the practical limit of monitoring frequency is one reading every

15 minutes of operation. Instead of requiring that each batch episode be monitored at least once,

the final rule requires an owner or operator to measure and record the parameter level at least
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once every 15 minutes during the period in which the control device “is functioning in achieving

the HAP removal required” by the rule. This means that one reading must be taken for every

15-minute period of continuous venting from any combination of emission episodes manifolded

to the control device. Thus, even when individual emission episodes are shorter than 15 minutes,

one reading is required if venting occurs for at least 15 minutes due to overlapping or

“contiguous” episodes. On the other hand, no monitoring would be required if each of the

emission episodes that an owner or operator is controlling to comply with the rule last less than

15 minutes, and they are separated by periods of no flow or venting from vents that do not need

to be controlled. For storage tanks, a control device is considered to be functioning in achieving

the HAP removal required at all times material is stored in the tank; although working losses

occur only during relatively short periods when the tank is being filled, breathing losses may

occur at any time. To identify periods of no flow, a flow indicator (not necessarily a flow

monitor) would be required.

An exception to the procedures described above exists if the owner or operator

establishes separate monitoring levels for different emission episodes. In this case, at least one

reading must be taken each time the level changes, even if episode lasts less than 15 minutes. 

This exception is included to counteract the possibility of setting multiple levels in order to avoid

monitoring.

As a result of the change in monitoring frequency, the definition of a valid hour of data as

used in the definition of an excursion also has been modified in the final rule. At proposal,

monitoring data would not constitute a valid hour of data if measured values are unavailable for

any of the 15-minute periods within the hour. For the final rule, the word required has been

added before the phrase “15-minute period” to address the fact that less than four data points per

hour may be allowed in some situations.

The EPA believes that the requirement to take 15-minute readings for devices controlling

more than 1 ton/yr of HAP is reasonable. The cutoff for continuous monitoring was set because

EPA wanted to reduce the compliance burden on facilities with smaller control devices. The

EPA also notes that “periodic” monitoring could increase the potential for being out of

compliance with the standard, because a reduction in the number of data points places a
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significantly higher emphasis on each reading for compliance determination. Additionally,

because emission stream characteristics in this industry are variable, the use of “periodic”

readings may not represent true conditions over the monitoring period.

16.5 QUALITY CONTROL PROGRAM AND PERFORMANCE EVALUATIONS OF

CONTINUOUS MONITORING SYSTEMS

Comment: According to commenter IV-D-28, §§ 63.8(d) and (e) and 63.10(e)(2)(i) of the

General Provisions should not apply because the quality assurance program and performance

standards for continuous monitoring systems (CMS) are directly regulated through the startup,

shutdown, and malfunction plan and the requirement to report any exceedances in the Periodic

reports.

Response: The quality control and performance evaluation procedures for CMS in

§§ 63.8(d) and (e) are not covered in the startup, shutdown, and malfunction plan, nor are they

addressed by the requirement to report exceedances in the Periodic reports. Therefore, these

provisions are applicable in the final rule. The final rule also specifies the required accuracy and

calibration procedures for selected parameter monitoring devices that must be taken into

consideration in the quality control plan.

16.6 MONITORING DURING STARTUP, SHUTDOWN, AND MALFUNCTION

Comment 1: Commenter IV-D-16 stated that § 63.1365(d) of the proposed rule should be

revised to clarify that startup, shutdown, and malfunction provisions apply to monitoring

equipment as well as process and control equipment.

Response: The EPA agrees with the commenter. The final rule specifies that startup,

shutdown, and malfunction provisions apply to monitoring equipment as well as process and

control equipment. This change makes the final rule consistent with other regulations such as the

HON, pharmaceuticals and polymers and resins.

Comment 2: Commenter IV-D-28 raised several issues about how the startup, shutdown,

and malfunction provisions relate to data availability requirements and violations. First, the

commenter stated that monitoring data collected during any startup, shutdown, or malfunction

and during periods of nonoperation of the process should be excluded from the daily averages. 

Second, the commenter believes the rule should clearly specify that there is no violation if an
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event such as a malfunction results in insufficient data or an exceedance of a parameter. Third,

the commenter expressed concern about the requirement in § 63.1365(d) of the proposed rule,

which stated that an excursion is not a violation if it happens during a startup, shutdown, or

malfunction and the facility follows its startup, shutdown, and malfunction plan. The commenter

interprets this provision to mean that EPA could assess two penalties if the plan is not followed--

one for not following the plan, and, because the plan was not followed, a second for the

excursion.

Response: If monitoring data obtained during a startup, shutdown, or malfunction result

in an exceedance, the exceedance is not a violation as long as the facility follows the startup,

shutdown, and malfunction plan. However, if the facility does not follow the plan, an

exceedance would be a violation, but it would not be two violations. Thus, the final rule retains

the requirement to use data obtained during any startup, shutdown, and malfunction in daily

averages.

Similarly, if a startup, shutdown, or malfunction results in the inability to collect

monitoring data, it may cause an excursion. This excursion would not be a violation if the

facility followed its startup, shutdown, and malfunction plan, but it would be a violation if they

did not follow the plan.

As noted in the response to the comment in section 16.4, the final rule requires

monitoring when the control device is functioning in achieving the HAP removal required by the

rule. Thus, data obtained during time when the process is not operating are not to be used in

determining the daily average of the parameter level.

16.7 MONITORING FOR STORAGE VESSEL CONTROLS

Comment: Commenter IV-D-28 believes the proposed rule lacks appropriate monitoring

provisions for control devices that are used to control emissions from storage vessels. According

to the commenter, the proposed provisions address only continuous monitoring, which often will

not be appropriate for storage vessels because the emissions occur primarily during filling. 

Furthermore, if emissions are controlled using a disposable carbon canister, the monitoring may

consist only of replacing the canister before the end of its rated life, not periodically checking a

parameter. Therefore, the commenter recommended that EPA include some of the concepts from
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the storage tank monitoring provisions in § 63.120(d) of the HON. For example, these

provisions specify that the owner or operator must prepare a monitoring plan that describes how

the monitoring will be done. In addition, the commenter indicated that the rule needs to define

“excursion” for situations where monitoring is not continuous (e.g., the rule should specify that

the monitoring plan “shall define an excursion in terms of the relevant operating parameter”).

Response: The monitoring provisions in § 63.1365(b) of the proposed rule were intended

to apply to all types of control devices except those used for continuous processes. In the final

rule, the provisions from §§ 63.1365(a) and (b) have been consolidated into one section that

specifies monitoring provisions for all control devices. The final rule also includes monitoring

provisions for nonregenerative carbon canisters; the owner or operator is required to determine

the maximum time interval between replacement based on operation under absolute or

hypothetical peak-case conditions and to replace the canister before this time elapses.

Unlike the HON, the final PAI rule requires the same type of monitoring regardless of the

purpose for which the control device is used. The EPA does not believe it is necessary to have

different procedures for storage tank control devices because the types of emission episodes from

storage tanks are comparable to those from batch process vents. Furthermore, most storage tanks

at the surveyed PAI plants emit less than 0.91 Mg/yr. Under the final rule, if the total

uncontrolled HAP emissions entering a control device are less than 0.91 Mg/yr, the owner or

operator may elect to conduct a periodic (at least daily) verification that the control device is

operating properly. The verification procedures are to be described in the Precompliance plan. 

This provision is comparable to the monitoring plan concept described in § 63.120(d)(2) of the

HON. As noted in the response to the comment in section 16.4, if the total uncontrolled HAP

emissions entering the control device exceed 1 ton/yr, the owner or operator must monitor the

appropriate parameter(s) every 15 minutes during which the control device is functioning in

achieving the HAP removal required by the rule. Based on information from the surveyed PAI

facilities, this situation would apply to very few storage tanks in the PAI industry. Most of the

few tanks with emissions greater than 0.91 Mg/yr are vented to the same control device that is

used to control process vent emissions. Thus, a separate set of monitoring requirements for

storage tank control devices is not needed.
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For devices that control more than 0.91 Mg/yr of HAP, the definition of excursion in the

final rule is the same as that in the proposed rule, and it is applicable to all control devices. 

Specifically, a valid hour of monitoring data must be obtained for 75 percent of the hours that a

control device operates during a day (or, if the control device operates less than 4 hours, at least

3 hours of valid data must be obtained). As noted in the response to the comment in section 16.4

of this chapter, the control device operation is based on the time when the control device is

functioning in achieving the HAP reduction required by the rule. For storage tanks, this means

all of the time that the storage tank contains material. When compliance for small control

devices is demonstrated by conducting a periodic verification, the final rule has been revised to

clarify that not conducting the verification is an excursion.

The final rule also clarifies that exceedances of operating parameters are those times

when (1) the parameter level, averaged over the operating day, is above a maximum or below a

minimum established during the initial compliance demonstration, or (2) the required operating

characteristic is not met (e.g., loss of all pilot flames for a flare). If compliance is demonstrated

by conducting a periodic verification, an exceedance occurs any time the daily, or more frequent,

demonstration does not confirm that the control device is operating properly.

16.8 DATA AVAILABILITY REQUIREMENTS

Comment: Commenter IV-D-16 indicated that the applicability of § 63.8(c)(7) in Table 1

should be changed to “yes” to indicate that “recorded data shall not be used in data averages or

calculations, or to meet any data availability requirement when the data are recorded during outof-control periods, repairs, maintenance periods, calibration checks, and zero (low-level) and

high-level calibration drift adjustments.”

Response: Section 63.8(c)(7) of the General Provisions describes out-of-control

situations for continuous monitoring systems. It also indicates that during out-of-control periods,

recorded data are not to be used in data averages or other data availability requirements

established under part 63. This section of the General Provisions was not applicable in the

proposed rule, and is not applicable in the final rule, because the out-of-control situations

described in this section (i.e., zero and high-level calibrations and audits) are not applicable to

parameter monitors. In addition, maintenance and repair periods are covered by the startup,
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shutdown, and malfunction plan. As noted in the response to comment 2 in section 16.5, the rule

itself includes language requiring the use of data collected during any startup, shutdown, or

malfunction.

16.9 VIOLATIONS

Comment 1: Several commenters (IV-D-14, IV-D-16, and IV-D-28) addressed situations

that would result in violations under the proposed rule. All of the commenters asserted that

excursions or exceedances of an operating parameter should not be violations of the emission

standard; commenter IV-D-28 also stated that failure to take corrective action after a bag dump

alarm should be a violation of a work practice requirement, not the particulate HAP emission

standard. Commenter IV-D-28 stated that such excursions should not be a violation of an

emission standard because the parameters are only indicators of proper operation, they do not

prove compliance with an emission standard. Commenter IV-D-14 stated that the proposed

provision conflicts with the basis of the compliance assurance monitoring (CAM) regulation. 

Commenters IV-D-16 and IV-D-28 stated that the requirement in § 63.1365(a) to “operate

processes and control devices within the parameters” must be revised because they interpreted

this statement to mean that each datapoint must be within the established limit. Commenter IVD-16 indicated that the source must be allowed to demonstrate continued compliance with the

emission standard despite exceedance of a monitoring parameter. Commenter IV-D-28 indicated

there are startup, shutdown, and malfunction exceptions (as described in comment 2 in

section 16.6), and only the daily average value (not each data point) is used to demonstrate

compliance.

Response: The EPA’s policy is that new part 63 rules, in particular those that require the

use of a control device to reduce pollutant emissions, will include compliance determinations on

two levels. The first level is the “traditional” performance test requirement that is based on the

use of a specific test method over a set period of time and operating conditions. A performance

test is generally conducted when the rule is effective (e.g., at facility startup or after an effective

date for an existing facility) and may be repeated periodically thereafter. The results of the

performance test are compared with an emission limitation (e.g., concentration, control
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efficiency, or mass rate). The second level of the compliance determination in part 63 rules is the

continuous compliance obligation, which is implemented through monitoring.

In general, the EPA recognizes two basic approaches to monitoring. One method is to

establish monitoring as a direct measure of continuous compliance. Under this continuous

compliance monitoring approach, an enforceable value of the monitored parameters is defined

and measured. The Agency has adopted this approach in part 63 standards, and is committed to

following this approach whenever appropriate in future rulemakings. Another approach is to

establish monitoring to provide a reasonable assurance of compliance by documenting continued

proper operation of the control devices, indicating excursions from proper operating conditions,

and correcting the problems that cause excursions. This second approach is the basis of the

CAM rule, which applies to sources that are not currently subject to part 63 standards.

When a part 63 rule specifies a surrogate pollutant continuous emissions monitoring

system(s) (CEMS) or parameter monitoring for demonstrating continuous compliance, the rule

includes specific limitations and averaging times for these alternative situations. The surrogate

pollutant or operating parameter limit becomes an enforceable limit for the rule. There is no

requirement that an alternative limit, whether a surrogate pollutant or an operational parameter,

be statistically correlated with emissions or the compliance level of the regulated pollutants(s). 

The alternative limit is a separately enforceable requirement of the rule. The alternative is not

secondary to the emission limit; rather, it is applied in lieu of continuous emission limit

obligation.

The enforceable level for the surrogate pollutant or operating parameter may be based on

measurements made during a performance test or other conditions specified by the part 63 rule. 

In any case, the alternative limit becomes the continuous compliance obligation and fulfills the

second level of compliance for the rule.

The EPA has considered the commenters’ argument that an exceedance of a monitoring

parameter is not necessarily an exceedance of an emission limit. The Agency acknowledges that

a parameter exceedance does not necessarily mean that the source has exceeded the emission

limit. However, as discussed above, under EPA’s approach to continuous compliance in part 63

rules, the continuous parameter monitoring limit is a separate requirement that is not rebuttable
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through contrast with actual or estimated HAP emission values. In addition, EPA believes that

given the flexibility the owner or operator has to select operating parameters, including the

option that allows the owner or operator to set different parameter levels for different operating

conditions, the burden is on the source to remain within the operating limit defined for the

parameter or parameters.

To address the potential disparity between parameter limit exceedances and emission

limit exceedances, the final rule contains two different types of continuous compliance

violations. When a source is using a CEMS to monitor compliance with the 20 ppmv alternative

standard, an exceedance is defined as a violation of the emission limit. Similarly, because the

exit gas temperature of a condenser is so closely correlated with emissions, a condenser

temperature exceedance is considered a violation of the emission limit. Exceedances of other

types of parameter limits are defined as violations of an operating limit. Failure to initiate the

corrective action plan after a bag leak detector alarm also is a violation of an operating limit.

Finally, for the final rule, §§ 63.1365(a) and (b) of the proposed rule have been combined

and revised to clarify the monitoring requirements. It was never EPA’s intent to base compliance

on each individual datapoint. Therefore, the first paragraph in the monitoring section of the final

rule has been changed to read as follows:

To provide evidence of continued compliance with the standard, the owner or operator of

any existing or new affected source shall install, operate, and maintain monitoring

devices as specified in this section. During the initial compliance demonstration,

maximum or minimum operating parameter levels or other design and operating

characteristics, as appropriate, shall be established for emission sources that will indicate

the source is in compliance. Test data, calculations, or information from the evaluation of

the control device design, as applicable, shall be used to establish the operating parameter

level or characteristic.

The section then goes on to describe the types of parameters to monitor; it explains how to

establish the parameter levels and averaging periods; and it defines exceedances, excursions, and

violations.

Comment 2: Commenter IV-D-28 believes the rule should allow for a specified number

of excused excursions per reporting period, as in other MACT standards.
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Response: The final rule does not included excused excursions. Excused excursions

were allowed in the HON to allow facilities time to become familiar with the new monitoring

provisions in the HON. The excursions were not meant to be precedent setting for all future

rules. The EPA believes that industry in general has had sufficient time to develop strategies for

complying with monitoring requirements, and that excused excursions are no longer necessary. 

Other recent rules also have been issued without excused excursions.

Comment 3: Section 63.1366(d) of the proposed rule specifies that for unit operations

occurring more than once per day, exceedances of established parameter limits shall result in no

more than one violation per operating day for each monitored item of equipment utilized in the

unit operation. Commenter IV-D-28 supports the concept that there should be no more than one

violation per day for exceedances of operating parameters, but suggested incorporating it into a

different part of the rule. The commenter pointed out that § 63.1367(b)(2) addresses this concept

for excursions (i.e., periods of “insufficient data”). The commenter suggested that exceedances

of operating parameters be called a “parameter level” excursion, specify that § 63.1367(b)(2)

applies to parameter level excursions, and delete § 63.1366(d). The commenter also believes

§ 63.1366(d) is unclear because “unit operations” are equipment, they do not “occur.”

Response: Several changes have been made in the final rule to clarify the definitions of

exceedances, excursions, and violations. For the final rule, the definition of excursions has been

moved from the reporting section to the monitoring section, and a definition of exceedances has

been added to the monitoring section. The provision in § 63.1366(d) of the proposed rule has

been revised and moved to the monitoring section as well. For the final rule, this provision reads

as follows: “. . . for emission episodes occurring more than once per day, exceedances of

operating parameters or excursions will result in no more than one violation per operating day for

each monitored item of equipment utilized in the process.”

Comment 4: Commenter IV-D-16 urged EPA to add a provision to protect an affected

source that discharges to a POTW from compliance violations under this rule if the POTW has a

violation of their permit.

Response: The final rule cross-references the offsite treatment provisions in § 63.132(g)

of the HON, which is identical to the proposed requirements. These provisions require a
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“transferee” (e.g., a POTW) to submit a written certification to EPA stating that the transferee

will manage and treat any Group 1 wastewater stream or residual removed from a Group 1

wastewater stream in accordance with the requirements in subpart G. Furthermore, if a POTW

provides such a written certification, § 63.132(g)(3) states that the POTW accepts responsibility

for compliance with the wastewater provisions in the HON for any wastewater covered by the

certification, and is subject to enforcement action for violations.

16.10 MISCELLANEOUS

Comment 1: According to commenter IV-D-28, the provisions for heat exchangers and

equipment leaks in §§ 63.1365(d) and (e) are out of place because the monitoring for this

equipment is the emission limitation (or means of reducing emissions); the monitoring is not

used to demonstrate compliance with an emission limitation. For this equipment, there is no

“monitoring” to demonstrate compliance, except recordkeeping and reporting, which are stated

elsewhere.

Response: The commenter is correct that the standards for equipment leaks and heat

exchangers consist of monitoring requirements. Therefore, §§ 63.1366(d) and (e) in the final rule

state this fact and indicate that no additional monitoring is required to demonstrate continued

compliance with the standards.

Comment 2: Commenters IV-D-14 and IV-D-27 requested changes in the monitoring

requirements to more closely match the requirements in the CAM rule. Commenter IV-D-27

believes that cutoffs in § 63.1365 for requiring continuous monitoring should be the same as

those in the CAM rule (i.e., 10 or 25 ton/yr, not 1 ton/yr). The commenter based this comment

on a statement in section II.B of the preamble to the final CAM rule. Commenter IV-D-14 stated

that the monitoring requirements should be revised to coincide with the principles of CAM.

Response: As discussed in the response to comment 1 in section 16.9, CAM is one of

two basic approaches to monitoring, but it was developed for sources that are not currently

subject to part 63 standards. Furthermore, as noted in the response to the comment in

section 16.4, the provision allowing a facility to demonstrate compliance by conducting periodic

verifications for devices that control less than 1 ton/yr of HAP was included in the proposed rule

to minimize the burden on small facilities. The EPA does not believe raising this cutoff is
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warranted. Therefore, the cutoffs for the monitoring provisions in the proposed rule are retained

in the final rule.

Comment 3: Commenter IV-D-27 believes the rule should state that monitoring and

inspection provisions under RCRA can be followed instead of corresponding MACT provisions

for air and/or wastewater routed to RCRA incinerators covered under subpart O of either 40 CFR

part 264 or part 265.

Response: The RCRA provisions are as stringent or more stringent than the requirements

in the final rule. Therefore, § 63.1362(l) of the final rule specifies that a RCRA incinerator used

to control emissions is exempt from monitoring requirements of the rule. The final rule also

cross-references § 63.138(h) of the HON, which exempts RCRA units that are used to treat

wastewater from the monitoring provisions.

Comment 4: Commenter IV-D-28 supports the concept of allowing periodic verifications

rather than monitoring for small control devices, but suggested that this section also specifically

state that continuous monitoring is allowed.

Response: The Agency appreciates the support of the commenter in allowing periodic

verifications rather than monitoring for small control devices. In addition, the final rule states

that, for small control devices, the owner or operator may elect to comply with the continuous

monitoring provisions rather than the periodic verification requirements.

Comment 5: Section 63.1365(b)(2)(iii) of the proposed rule specifies that an owner or

operator may establish monitoring parameters based on “the performance test supplemented by

engineering assessments and manufacturer’s recommendations.” Commenter IV-D-28 suggested

adding the words “if desired” after the word “supplemented” and change the word “and” to

“and/or.” This commenter also recommended deleting the words “The procedures in this

section have not been approved by the Administrator” because this suggests that the provisions

are unacceptable or have been disapproved.

Response: The words “if desired” are not necessary because the provision already states

the owner or operator may use the procedure as an alternative to establishing parameter levels

based solely on performance test data. In the final rule, the word “and” has been replaced with

“and/or” because the test data may be supplemented using an engineering assessment,
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manufacturer’s recommendations, or both. The words “The procedures in this section have not

been approved by the Administrator” were deleted because they are considered to be

unnecessary. The final rule retains the statement that any procedures an owner or operator uses

to develop additional monitoring parameter levels are subject to approval by the Administrator.

16.11 EDITORIAL CLARIFICATIONS

Comment: Commenter IV-D-28 requested all five of the following editorial clarifications

in § 63.1365; commenters IV-D-21 and IV-D-29 also requested the fifth clarification:

1. The term “parameter level” (not just “parameter” or “operating parameters”) should be

used consistently to describe the limit within which the daily average parameter value must be

maintained.

2. The first sentence of § 63.1365(b) needs clarification because it is not clear how an

owner or operator may “choose” to comply with the emission limit or emission reduction.

3. The type of emissions needs to be specified every time a quantity of emissions is

specified (e.g., 9.1 tons of organic HAP, not just 9.1 tons of HAP).

4. Add “as specified in this section” to the end of the first sentence in § 63.1365(a). 

5. Section 63.1365(a)(6) should be corrected to indicate that a deviation occurs when

combustion chamber temperatures are lower, not greater, than the parameter value.

Response: The EPA agrees with the commenters’ suggestions. As noted elsewhere in

this chapter, the monitoring provisions have been significantly rearranged and clarified in the

final rule. All of the editorial changes and corrections suggested by the commenters have been

incorporated in the final rule.
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17.0 RECORDKEEPING

17.1 RECORDKEEPING BURDEN

Comment: Two commenters (IV-D-28 and IV-G-03) commented on the burden to

comply with the recordkeeping requirements. Commenter IV-G-03 stated that over 100 different

records must be maintained daily, monthly, quarterly, or annually; therefore, the commenter

urged EPA to review the recordkeeping requirements to ensure that such extensive recordkeeping

is necessary. Commenter IV-D-28 supports provisions in §§ 63.1366(a) and (a)(3) that require

an owner or operator to maintain records of only the daily average of the parameter values, not

each datapoint, because this reduces the recordkeeping burden. However, this commenter also

stated that a reduced recordkeeping option, like that in § 63.152(g) of the HON, should be added

to the rule if EPA decides to change these provisions and require records of shorter term values.

Response: Detailed records are needed to demonstrate compliance with the regulation. 

However, prior to proposal, EPA made a concerted effort to eliminate duplicative and

unnecessary recordkeeping requirements because EPA recognizes that these requirements would

burden both the affected sources and EPA enforcement agencies. Since proposal, EPA has

reviewed the recordkeeping provisions and made a number of changes. Many of the changes are

editorial revisions designed to clarify the requirements. Some of these clarifications are

discussed in more detail in other responses in this chapter. Other clarifications explicitly state

recordkeeping requirements that were merely implied in the proposed rule (e.g., records of

planned routine maintenance and records of the absolute or hypothetical peak-case conditions for

process vent testing).

The final rule also includes additional recordkeeping requirements to document

compliance with new or revised provisions in the rule. For example, the final rule includes
17-2

recordkeeping to document the primary use for material produced by PAI process units if the

primary use is not as a PAI (see section 3.2 for a discussion of the new primary use provisions). 

Another example in the final rule includes procedures to demonstrate ongoing compliance with

the annual emission limit for process vents by calculating an annual rolling summation every day,

and records of these calculations must be maintained. Finally, § 63.1362(j) was added to the

final rule to specify that bypass lines that could divert a vent stream away from a control device

must be monitored either with a flow indicator or by visual inspection of the seal or closure

mechanism that secures the valve in the closed position; records of any flow or the results of

inspections must also be maintained.

One additional change involves the parameter monitoring records in §§ 63.1366(a) and

(a)(3) that were cited by the commenter. After reviewing these requirements, EPA now believes

that, even when the daily average is in compliance, it is necessary to maintain all parameter

readings, not just the daily averages. This rule requires that owners and operators select only

parameter readings that are taken when the control device is controlling HAP emissions from

affected emission streams. Emission episodes from batch processes, which predominate in the

PAI production industry, are discontinuous. As a result, some monitoring readings may occur

during periods of no flow for affected streams (although there may be flow of nonaffected

streams). Readings taken during these periods must be excluded from the daily averages. In

order to verify that the daily average values were calculated correctly, the rule requires owners

and operators to keep all data. The EPA also does not believe that the approach in § 63.152(g) of

the HON would be appropriate for this rule because, unlike this rule, the HON regulates emission

streams with continuous flow. 

17.2 RECORDS OF GROUP 1 DETERMINATIONS

Comment: Commenter IV-D-28 believes that records of Group 1 stream determinations

should not be required.

Response: The final rule requires an owner or operator to keep records of the results of

all Group determinations for process vents, storage vessels, and wastewater streams. The owner

or operator is not required to keep records of how streams were determined to be Group 1

streams; in fact, for storage vessels, the final rule allows the owner or operator to designate
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Group 1 storage vessels. However, some of the same information may be required for other

reasons. For example, as described in section 17.4, records of uncontrolled process vent

emission estimates are required if the owner or operator complies with the requirements to

reduce emissions from the sum of all process vents within a process by 90 percent. Records of

emission estimates are also required for all emission streams that are used in emissions

averaging, and records of wastewater stream concentrations and flowrates are needed for some of

the treatment options. Alternatively, an owner or operator complying with an outlet

concentration standard is not required to keep these records (although records of flow rates may

be needed to show compliance with corrections for supplemental gases). 

By definition, if a stream is not Group 1, then it is Group 2. Therefore, the owner or

operator also must keep records of the Group 2 determinations because these data are needed to

demonstrate compliance with the applicability cutoffs. 

17.3 RECORDS OF TURNOVERS

Comment: Section 63.1365(b)(5) of the proposed rule would require owners and

operators to keep records of tank turnovers. Three commenters (IV-D-21, IV-D-28, and

IV-D-29) opposed this provision. Commenter IV-D-28 stated that there is no substantive

requirement in the regulation that these records would support, and even if turnovers must be

recorded, this commenter questioned whether calculations rather than monitoring results would

be acceptable. Commenters IV-D-21 and IV-D-29 stated that turnovers should be required only

for tanks complying with the 110 kg/yr cutoff; such records are not needed when emissions are

controlled.

Response: The EPA agrees with the above comment for most cases, especially since the

storage tank mass emissions applicability cutoff was eliminated in the final rule. Actual

emissions from a tank are only needed for emissions averaging and for determining whether

emissions from a new PAI process unit exceed 10/25 tons/yr and thus would be subject to new

source standards. Turnovers are used to calculate working losses and thus would be one of the

parameters that must be recorded only as part of either the emissions averaging calculations or

new source determination.

17.4 RECORDS OF PROCESS VENT EMISSIONS
17-4

Comment: Section 63.1366(b)(1) of the proposed rule would require an owner or

operator to maintain records of “the emissions of gaseous organic HAP and HCl per batch for

each process.” Commenter IV-D-28 believes this provision implies that CEMS would be

installed on every emission point, which conflicts with the compliance provisions. Thus, the

commenter believes this provision should be deleted.

Response: The provision is reworded in the final rule to clarify that records must be kept

of the initial calculations (and supporting data) used to estimate uncontrolled and controlled

emissions of each emission event from Group 1 process vents if the owner or operator is

complying with the 90 percent reduction requirement. These are the same data that would be

used to determine that the vents within a process are Group 1, but records of Group 1

determinations are not required (as noted in section 17.2) because the data are not needed if the

owner or operator is complying with the outlet concentration requirement of 20 ppmv, or is using

a flare. The provision is retained in the final rule because these data are needed to demonstrate

initial compliance with the percent reduction requirements. A copy of the NOCS report (and

updates to these data and calculations contained in Periodic reports) would satisfy this

requirement because the same information must be submitted in that report.

17.5 RECORDS OF WASTEWATER CHARACTERISTICS

Comment: Section 63.1366(b)(2) of the proposed rule would require an owner or

operator to maintain records of “wastewater concentrations and flowrates per POD and process.” 

Commenter IV-D-28 believes this statement could be interpreted either of two ways, but

regardless of which interpretation is correct, the provision should be deleted. For example, it

could mean annual average values, but if so, the commenter believes this record would be

unnecessary because there must be a requirement elsewhere in the regulation to keep records

supporting Group determinations (except for Group 1 determinations, as noted in the comment in

section 17.1). Alternatively, it could mean continuous “real time” records, which the commenter

points out conflicts with the compliance requirements and should not be required; thus there will

be no data from which to create the records.

Response: The provision is referring to the annual average values. Contrary to the

commenter’s belief, recordkeeping requirements are specified only in § 63.1366. Other sections
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of the rule specify that the concentrations and flowrates must be estimated for use in determining

compliance. Therefore, the provision is retained in the final rule.

17.6 RECORDS OF BAG LEAK DETECTION ALARMS

Comment: Section 63.1366(a)(5) of the proposed rule would require an owner or

operator to maintain records of any bag leak detection alarm and the corrective action taken. 

Commenter IV-D-28 believes corrective action would not always be necessary and, therefore, the

following phrase should be added to the end of the proposed provision: “or the reason why no

corrective action was taken.”

Response: The provision has been clarified in the final rule but was not changed as

suggested by the commenter. In the final rule, the provision requiring the owner or operator to

keep records that document the date and time of the alarm, the cause of the alarm, and the

corrective action taken is in § 63.1367(b)(5). Note that under § 63.1368(e)(6), a corrective action

plan must be submitted with the Precompliance plan. The corrective action plan must describe

procedures for the proper operation and maintenance of fabric filters, procedures used to

determine and record the time and cause of an alarm, and corrective actions to be taken when the

alarm is triggered. If there are situations that the owner or operator believes do not require

corrective action (other than resetting the alarm), they must be identified in the corrective action

plan.

17.7 LOCATION OF RECORDS

Comment: Commenter IV-D-28 believes that the rule, like the HON, should include

provisions specifying where to keep records. For example, the HON defines “onsite” and

requires that records from the most recent 6 months be kept onsite (or accessible within 2 hours);

records from the preceding 4.5 years may be kept offsite.

Response: Section 63.1366(a) specified that “records shall be kept in accordance with the

requirements of applicable paragraphs of § 63.10 of subpart A of this part, as specified in the

General Provisions applicability table of this subpart (Table 1).” Section 63.10(b)(1) of the
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General Provisions specifies that records must be retained for at least 5 years, and, at a minimum,

the most recent 2 years of data shall be retained onsite, and the remaining 3 years of data may be

retained offsite. Onsite means the same thing as the “plant site that is a major source,” as stated

in the definition of the affected source in § 63.1360(a).

17.8 OVERLAP WITH RCRA RECORDKEEPING REQUIREMENTS

Comment: Commenter IV-D-27 believes the rule should state that an owner or operator

may follow the recordkeeping provisions under RCRA instead of the corresponding

recordkeeping requirements in § 63.1366 for air emissions and/or wastewater routed to RCRA

incinerators covered under 40 CFR part 264/265 subpart O.

Response: The EPA agrees with this comment. Therefore, § 63.1362(l) of the final rule

exempts streams that are discharged to RCRA incinerators or boilers and industrial furnaces

meeting Subpart O from all requirements of the rule, except for identification in the NOCS

report.

17.9 CLARIFICATIONS

Comment 1: Commenter IV-D-28 believes the phrase “up-to-date” should be deleted

throughout § 63.1366 for two reasons. First, it means nothing for one-time records, and second,

it is unnecessary for continuous records because other portions of the rule already require records

of successive data.

Response: The EPA disagrees with the commenter. “One-time” records are subject to

change based on changes in the process. The requirement to maintain records of continuous

monitoring data or results of periodic calculations exists only in § 63.1366 of the proposed rule;

other sections of the rule specify only such things as the types of parameters that must be

monitored, the types of calculations that must be performed, and the frequency of these activities. 

Therefore, the phrase “up-to-date” is retained in the final rule.

Comment 2: Section 63.1366(e) of the proposed rule specified that no more than one

violation per operating day would be assessed “for certain items of monitored equipment used for
17-7

more than one type of unit operation in the course of an operating day.” Commenter IV-D-28

requested clarification of this section. For example, the “certain items” of monitored equipment

are not defined.

Response: The definitions of exceedances and excursions, and how these occurrences

constitute violations are clarified in § 63.1366(b)(6) of the final rule (see chapter 16 for

additional information about these changes). The term “certain items” is not used in the final

rule.
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18.0 REPORTING

18.1 PRECOMPLIANCE PLAN

Comment: Commenters IV-D-21 and IV-D-29 stated that the requirement for a

Precompliance report in § 63.1367(a)(2) of the proposed rule should be deleted, as it was for the

HON.

Response: The EPA believes the Precompliance report (or precompliance plan in the

final rule) is a valuable tool for the regulatory agency responsible for making compliance

determinations for the affected source. It provides an enforcement official or inspector with

some initial background information about the process being controlled, the types of emissions

associated with the process, corresponding control equipment, and the monitoring parameters

that have been or will be correlated to the process conditions. 

The Precompliance plan is also the mechanism by which the affected source requests

approval to use alternative monitoring parameters and to use calculations or other compliance

procedures that differ from those prescribed in the rule. Because many of the compliance

procedures for this rule are more complicated than those for the HON, EPA believes the

Precompliance plan requirement is warranted for this industry and has retained the provision in

the final rule.

Comment: Section 63.1367(a)(2)(iii) of the proposed rule would require the owner or

operator to include in the Precompliance plan “a description of test conditions and limits of

operation for control devices tested under normal conditions . . .” Commenter IV-D-28 requested

clarification of what is meant by “normal” conditions.
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Response: The language in this section of the proposed rule was an artifact of an earlier

approach and should have been deleted from the proposed rule. This provision has been

corrected in the final rule to require documentation of how monitoring parameter levels are

established under § 63.1366(b)(3)(ii)(B), including the test data, any calculations, and rationale

for why the level indicates proper operation of the control device. This section allows an owner

or operator to establish monitoring levels based on performance test results supplemented with

engineering assessments and manufacturer’s recommendations. Because the use of these

procedures is subject to approval by the Administrator, it must be included in the Precompliance

plan.

18.2 PERIODIC REPORTS

Comment 1: Several commenters (IV-D-21, IV-D-28, IV-D-29, and IV-G-03) addressed

the issue of the frequency of periodic reporting. Three commenters (IV-D-21, IV-D-28, and

IV-D-29) stated that periodic reporting should be changed from quarterly to semiannually. 

Commenter IV-D-28 provided three reasons for the change: (1) quarterly reporting would be an

unwarranted increase in burden compared to other MACT standards; (2) consistency among

standards makes it easier for a facility subject to many standards to comply; and (3) EPA has

proposed to harmonize the paperwork burdens of a wide variety of NSPS, part 61 NESHAP, and

other part 63 MACT standards. Commenter IV-G-03 noted that the title of § 63.1367(b) is

“Quarterly reports” but suggested changing it because § 63.1367(b)(3) would require submittal of

a report within 180 days after a process change. 

Response: The EPA re-evaluated the overall reporting requirements in the proposed rule 

and compared the proposed reporting requirements with requirements in rules for similar

industries. Based on this evaluation, the Agency decided to change the periodic reporting from

quarterly to semiannual. In those cases where the continuous emission monitoring data are used

to demonstrate compliance with the 20-ppmv alternative standards, and the source experiences

excess emissions, quarterly reporting is required until a request to reduce reporting frequency is

approved. Section 63.1368(g) in the final rule is now titled “Periodic reports” and details the

submittal schedule and content of the required Periodic reports. 
18-3

Comment 2: Commenter IV-D-28 believes the rule should indicate that Periodic reports

are due 2 months after the end of each reporting period.

Response: As mentioned in the response to comment 1 in this section, the Agency has

opted for semiannual Periodic reports. In concurrence with the comment, § 63.1368(g) of the

final rule details the submittal schedule and exceptions associated with the Periodic reports. In

short, Periodic reports are to be submitted within 60 operating days after the end of the applicable

reporting period.

18.3 NOTIFICATION OF COMPLIANCE STATUS REPORT 

Comment: Commenter IV-D-28 stated that the NOCS report submittal date in

§ 63.1367(a)(1) conflicts with the requirement in § 63.7(a)(2) to complete performance testing

within 180 days and the requirement in § 63.10(d)(2) to submit performance test reports 60 days

after the tests.

Response: The submittal date for the NOCS report in § 63.1368(f) of the final rule does

not conflict with the General Provisions requirements in §§ 63.7(a)(2) and 63.10(d)(2), it

supersedes it. As noted in Table 1 to Subpart MMM -- General Provisions Applicability to

Subpart MMM, “[T]est results must be submitted in the NOCS due 150 days after the

compliance date.” This means that the performance testing and the compilation of the test results

must be completed and submitted as part of the NOCS report which is due within 150 days after

the compliance date. Additional language was added to the final rule under § 63.1368(a) to

clarify which of the reporting requirements of subpart A (General Provisions) remain in effect for

this rule and which requirements have been superseded.

18.4 STARTUP, SHUTDOWN, AND MALFUNCTION REPORTS

Comment: Commenter IV-D-28 stated that § 63.8(c)(1)(ii) should not apply because if it

does apply there will be two sets of deadlines for reports of actions inconsistent with the startup,

shutdown, and malfunction plan--one affecting CMS and the other affecting all other periods of

startup, shutdown, and malfunction. According to the commenter, the deadlines should all be the

same and, ideally, the rule would require that all of this information be reported in the

semiannual periodic reports.
18-4

Response: The Agency agrees that two sets of inconsistent reporting deadlines are

cumbersome. As a result, the final rule overrides the 24-hour notification provisions of

§ 63.8(c)(1)(ii) and requires that all such notifications be reported within 2 days, consistent with

the provisions of § 63.6(e)(3)(iv). The Agency was not persuaded by the commenter’s

suggestion that all such notifications can be reported in the Periodic reports and has maintained

the reporting requirements (schedules) from the General Provisions § 63.6(e)(3)(iv) (related to

events covered and those not covered in the facility’s startup, shutdown, and malfunction plan). 

Furthermore, monitoring events or activities not covered by a source’s startup, shutdown, and

malfunction plan should be rare and are likely to be of interest to the enforcement agency. 

Reporting information to the enforcement agency within 2 working days will allow them to make

a timely evaluation (if needed or warranted) of the event, any associated excess emissions, and

the source’s response to the event. Repeated occurrences of events not covered by a source’s

startup, shutdown, and malfunction plan could prompt an enforcement agency to request a copy

of the startup, shutdown, and malfunction plan to review.

18.5 NOTIFICATION OF PROCESS CHANGE

Comment: Section 63.1367(b)(3) of the proposed rule would require notification of

process changes that cause an emission point to become a process vent with an emission rate of

1 lb/yr or more. Two commenters opposed this requirement. Commenter IV-D-16 stated that

this provision is not applicable to this standard and should be deleted. Commenter IV-D-15

stated that EPA needs to review and revise the definition of de minimis because l lb/yr is well

within the margin of error of the calculation methods and may not be significant. Another

commenter (IV-D-28) stated that the rule needs to specify how and when to report information

about changes that occur after the submittal deadline for a specific report. The commenter

suggested that it might be submitted no later than 60 days after it is obtained.

Response: The Agency decided to revise this section of the final rule based on these

comments. The final rule states that whenever a process change is made, or a change is made in

any of the information submitted in the NOCS report, a report must be submitted within 90

calendar days after the process change, unless the change requires approval prior to

implementation (such as a change that would consist of information submitted in the
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Precompliance plan). The report may be submitted as part of the next Periodic report, if one is to

be submitted within the 90-day period. This more general or “generic” approach avoids the

problems associated with trying to define de minimis emission levels as raised by the

commenters. The information to be reported is to include: a brief description of the process

change, a description of any modifications to standard procedures or quality assurance

procedures, revisions to any of the information reported in the original NOCS report, and

information required by the NOCS report for changes involving the addition of processes or

equipment.

18.6 EQUIPMENT LEAK REPORTS

Comment: According to commenter IV-D-28, § 63.1367(c) of the proposed rule should

specify the appropriate reporting deadlines for affected sources subject to the equipment leak

standards because the deadlines in the cross-referenced sections in subpart H are not appropriate.

Response: The commenter is correct in that the cross-referenced section in subpart H

does not match the rest of the reporting requirements in the proposed rule. With the reporting

frequency changed to semiannual (see previous comments and responses regarding Periodic

reports in 18.2), EPA decided to make the equipment leak reports consistent with the other

reporting requirements in the final rule. The equipment leak report(s) are to be included with the

NOCS report (due within 150 days of the compliance date) and with the Periodic reports (due

within 60 days after the end of each subsequent semiannual reporting period).

18.7 RECORDS OF REPORTS

Comment: Commenter IV-D-28 believes the requirement in § 63.1367(c) of the

proposed rule to maintain copies of properly-submitted reports as records is not appropriate for

two reasons. First, it imposes a paperwork burden with no environmental benefit and no purpose

except to be able to make a backup copy in the event EPA loses the original. Second, it creates

the potential for unfair “paperwork penalties” in the event the owner or operator cannot find it

when an inspector asks for it. The commenter recommended adding the following language,

based on an amendment to the HON: “If an owner or operator submits copies of reports to the

applicable EPA Regional Office, the owner or operator is not required to maintain copies of the
18-6

reports. If the EPA Regional Office has waived the requirement of § 63.10(a)(4)(ii) for submittal

of copies of reports, the owner or operator is not required to maintain copies of the reports.”

Response: The General Provisions (§ 63.10(b)(1)) require the owner or operator of an

affected source to maintain files of all information (including all reports and notifications) in a

form suitable and readily available for expeditious inspection and review. At a minimum, the

most recent 2 years of data shall be retained onsite. The regulatory agency responsible for

compliance assurance will be the likely end-user of such information if and when an inspection

or site visit is conducted. The paperwork burden associated with keeping copies of the data and

reports for the last 2 years onsite is not considered a significant burden. After the 2-year period,

electronic copies of the reports may be maintained at an offsite location for the additional 3-year

requirement. The EPA believes that the benefits of having the recent compliance reports

available onsite to an inspector (if needed) far outweigh the impacts or burden associated with

maintaining copies of the reports.

18.8 OVERLAP WITH RCRA REPORTING REQUIREMENTS

Comment: Commenter IV-D-27 believes the rule should state that an owner or operator

may comply with the reporting provisions under RCRA instead of the corresponding reporting

provisions in § 63.1367 of the proposed rule for air emissions and/or wastewater routed to a

RCRA incinerator covered under 40 CFR part 264/265 subpart O.

Response: The EPA agrees with the commenter. Therefore, § 63.1362(l) of the final rule

exempts streams that are discharged to RCRA incinerators or boilers and industrial furnaces

meeting subpart O from all requirements of the rule, except for identification in the NOCS

report.
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19.0 IMPACTS

19.1 ENVIRONMENTAL IMPACTS

Comment: Commenter IV-D-27 believes EPA did not adequately consider the secondary

air impacts of nitrogen oxides (NOx) formation caused by combusting nitrogen-bearing HAP

(and non-HAP VOC that may also be present) in process vent streams and wastewater.

Response: The impacts analysis was based on a small number of model streams with

characteristics that represent typical or average characteristics of streams at the surveyed

facilities. Very little nitrogen-bearing HAP is emitted from the surveyed facilities (less than

5 percent of both the total uncontrolled organic HAP emissions from process vents and the HAP

load in wastewater streams), and most of these HAP are controlled to the level of the standard. 

Therefore, the model emission streams that were used to estimate secondary air impacts did not

include nitrogen-bearing HAP. In addition, any small underestimate in the NOx emissions from

nitrogen-bearing HAP is likely more than offset by the use of conservative estimates in the

original analysis. For example, the estimated increase in NOx emissions were based solely on the

emissions associated with operation of the more efficient controls needed to achieve the level of

the standards; emissions from existing controls that would be replaced were assumed to be

negligible. The EPA has no evidence that non-HAP VOC compounds in emissions streams

contain significant amounts of nitrogen.

19.2 COST IMPACTS

Comment: Commenters IV-D-15 and IV-D-27 believe EPA underestimated the costs to

comply with the proposed rule. Based on recent experience installing some of the control

devices that are used in the cost analysis, commenter IV-D-27 believes the costs are

“significantly” underestimated, especially when the standard is more stringent than the floor. 
19-2

This commenter said their company would continue to review EPA’s cost analysis and might

provide their own detailed analysis at a later date; EPA has not received any additional

information from this commenter. Commenter IV-D-27 also indicated that, based on the

additional secondary air impact described in the comment above, the cost analysis should

consider the need to install best available control technology (BACT) or RACT technology to

control NO emissions. x

Commenter IV-D-15 believes none of the models used in the cost analysis adequately

address the situation at the commenter’s facility. This facility emits carbon disulfide, which,

when burned, generates a significant amount of SOx. The SOx is not an issue under the proposed

regulation, but it is a criteria pollutant that would have to be controlled under state regulations. 

As a result, the commenter believes EPA’s cost analysis underestimates the cost the commenter

would face for two reasons. First, the model is based on a thermal incinerator with 70 percent

recuperative heat recovery, but the commenter could not use this control device because carbon

disulfide has a low auto-ignition temperature; they would have to use either a thermal incinerator

with no heat recovery or a regenerative thermal oxidizer with 85 percent heat recovery. Second,

the scrubber that follows the incinerator would need to be able to control the SO emissions as x

well as HCl emissions. This commenter also stated that if their intermediate process meets the

definition of an intermediate (see comments in Section 3.3), either considerable changes to the

existing flare or a new flare would likely be needed to meet the provisions of the regulation.

Response: The cost impacts are based on models that represent a range of characteristics

at actual facilities. The models are expected to overestimate costs at some facilities and to

underestimate costs at others. It is possible that installing a control device could trigger the

requirement for a BACT or RACT analysis. Typically, to trigger BACT analysis the control

device would have to cause a net increase in NO emissions of 40 tons/yr (or any amount that has x

an impact of 1 microgram per cubic meter within 10 kilometers of a class I area). To increase

emissions by 40 tons/yr would require a very large incinerator; for example, the incinerator to

control the large model process with very low HAP concentrations was estimated to increase

NO emissions by only about 9 tons/yr. Typically, a facility has only two PAI processes. Thus, x

even if all emission streams are routed to the incinerator, and the emission streams contain

nitrogen-bearing HAP, it will be a very unusual situation for NOx emissions to increase by
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40 tons/yr. In the unlikely event that BACT is required, BACT is likely to be the use of low-NOx

burners, which are likely already part of the design of any new combustion devices. Although

RACT typically is applied to existing emission units, if it were to be applied to a new combustion

control device, RACT would also likely be low-NOx burners. As a result, EPA did not include

BACT or RACT technology in the models for the impacts analysis.

The SO control also was not included in the cost analysis because it is not a typical x

requirement, the amount of SO control that would be needed is unknown, and the cost is not 2

expected to be significantly different from that for an HCl scrubber. The total annual cost of a

thermal incinerator with no heat recovery is approximately equal to that for a thermal incinerator

with 70 percent recuperative heat recovery. The annual auxiliary fuel costs would be higher for

the incinerator without heat recovery, but these costs are nearly offset by lower capital recovery

costs as a result of lower capital costs. Although the performance of a given scrubber will be

better for HCl than for SO , a scrubber can easily be designed to obtain excellent SO removal 2 2

efficiencies.

Regarding the use of a flare that may not meet the specifications in the rule, if the owner

or operator believes it is achieving a 90 percent reduction, the owner or operator may develop

and submit for approval a procedure to demonstrate that it is complying with the required

reduction efficiency.

19.3 ECONOMIC IMPACTS

Comment: Commenter IV-D-15 believes EPA has not adequately evaluated the impact

of the proposed rule on small businesses. The commenter notes that the regulatory flexibility

analysis finds minimal impact on small businesses, but the docket states that the two known

small firms for which data were available were not surveyed to find the impact of the regulation

on them. The commenter believes a survey of small businesses is needed; otherwise the impact

on them is unknown. This issue is important to the commenter because at the time facilities

responded to the section 114 information request, the commenter’s plant was part of a large

business, but it has since been sold and is now classified as a small business.

Response: Prior to proposal, EPA estimated that the proposed regulation would affect

78 existing plants. The EPA confirmed company-level revenue data on 45 of the 78 existing
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plants that were estimated to be affected; the 45 plants are owned by 29 firms. Additionally,

EPA selected 9 large PAI manufacturing companies with multiple plants to collect detailed

information, which resulted in obtaining information for 20 plants altogether. This information

was used to estimated annualized costs of the proposed regulation. The EPA determined that 2

of the 29 firms are classified as small businesses, and each firm owns one plant. Because these

two small firms were not included in the more detailed survey of the 9 large PAI manufacturing

companies, direct costs associated with the proposed regulation were not available and average

control costs for modeled plants were used as an estimate of the control costs for the small firm

plants. Using the average control costs for model plants as an estimate for small firm plants’

control costs is a conservative approach (i.e., actual control costs for small firm plants are likely

to be smaller) because small firm plants are likely to be smaller in scale and have fewer distinct

processes per plant. The commenter’s facility was one of the 20 plants for which the more

detailed information was collected.

Since proposal, EPA reevaluated the impacts for the commenter’s facility. Revenue data

for the parent company of the new owner of this facility were obtained from Dun & Bradstreet. 

Cost impacts were unchanged from the original analysis. The resulting cost-to-revenue ratio for

this small business was estimated to be approximately 2.3 percent. As noted at proposal, the

control costs for model small businesses were also estimated to be less than 3 percent of revenue. 

This percentage suggests that the final rule does not significantly impact small firms in the PAI

manufacturing industry.
20-1

20.0 MISCELLANEOUS

20.1 STANDARDS FOR ENDOCRINE DISRUPTORS

Comment: In the preamble to the proposed rule, EPA solicited comment on whether the

risk posed by possible endocrine disruptors warrants more stringent requirements than those

proposed. Six commenters (IV-D-16, IV-D-21, IV-D-26, IV-D-28, IV-D-29, and IV-G-05)

opposed the development of more stringent requirements; none supported the idea. The

commenters cited a variety of reasons for not developing more stringent requirements: (1) the

science for determining disrupting properties of chemicals and their risks is still under

development; (2) technology-based standards are not appropriate to address endocrine disruption;

(3) endocrine disruption is not an adverse endpoint, but a mechanism of action; (4) the

compounds are emitted in small quantities; and (5) this has not been an issue under other MACT

standards that address essentially the same materials.

Response: In the proposal preamble EPA indicated that available information shows

emissions of possible endocrine disruptors is very low relative to other HAP emissions. Based

on these data and the comments, EPA has decided not to include more stringent requirements for

possible endocrine disruptors in the final rule. However, this decision does not preclude the

possibility that EPA may take action on endocrine disruptors in the future as new information

becomes available.

20.2 RISK-BASED STANDARD FOR HCl

Comment: The preamble to the proposed rule explained that section 112(d)(4) of the Act

provides EPA with authority, at its discretion, to develop risk-based standards for HAP “for

which a health threshold has been established,” provided that the standard achieves an “ample
20-2

margin of safety.” Because HCl is a threshold pollutant that is emitted from PAI manufacturing

facilities, EPA solicited comment on the adequacy, desirability, and feasibility of developing a

risk-based standard instead of a MACT standard for HCl emissions from PAI manufacturing

facilities. Three commenters addressed this issue. Commenter IV-D-17 opposed the

development of a risk-based standard for HCl emissions because it would delay promulgation of

the rule. Commenter IV-G-05 opposed development of a risk-based standard because the

proposed requirements are very similar to those proposed in the NESHAP for Steel Pickling

Facilities–HCl Process. Furthermore, this commenter believes a risk-based standard is not

needed because existing permit limitations based on ambient concentrations are protective of the

environment and human health, and the NESHAP limitations will only increase the permit’s

already protective nature. Commenter IV-D-28 supported EPA’s determination of HCl as a

threshold pollutant.

Response: The EPA agrees with the commenter that a risk-based approach would delay

promulgation of the rule. Given the relatively small potential difference between a MACT-based

standard and a risk-based standard, EPA believes that the small benefits are substantially

outweighed by the burden to EPA and the industry of collecting and analyzing the data needed

for a risk-based standard.

20.3 RELATIONSHIP BETWEEN THIS RULE AND OTHER RULES

Comment 1: Commenter IV-D-28 believes that wherever possible it would be better to

cross-reference other rules rather than to repeat or rephrase them in this rule because it will

(1) avoid unintentional changes in the language, (2) assure consistency if there are ever any

amendments, and (3) avoid tinkering with the wording in an effort to “improve” it. The

commenter wants to encourage consistency with other rules, especially the HON, because it

would facilitate compliance at the commenter’s large manufacturing facilities, each of which is

subject to several standards. At a minimum, the commenter believes that additional

opportunities for cross-referencing exist in the sections that specify provisions for heat

exchangers (i.e., §§ 63.1362(g), 63.1365(f), 63.1366(g), and 63.1367(e) of the proposed rule).

Response: As with all new regulations that overlap with other regulations or have similar

or identical requirements for specific emission sources, EPA has to make a decision as to when
20-3

and where regulatory text is written out and when it is cross-referenced. The points raised by the

commenter are valid concerns and were considered in the rule development and in drafting the

proposed regulatory text. For the most part, EPA utilized cross-referencing with the General

Provisions, the HON, and a few other rules. This provides uniformity and consistency for the

affected sources, as well as reducing the regulatory text to be included in the rule. However, in

some instances, specific language from other rules was incorporated directly into the proposed

rule in an effort to make it easier for the regulated community to understand the requirements.

Based on this comment, the Agency re-evaluated the heat exchanger provisions. 

Although much of the language from the HON was incorporated directly into the proposed rule,

large sections of the provisions were also cross referenced. The EPA determined that this partial

incorporation of language did not have the intended effect of enhancing understanding because

not only would the regulated community have to refer to another rule for some of the provisions,

but they would also have to read both rules closely to check for differences. Therefore, the final

rule cross-references all of the heat exchanger provisions, and notes a few exceptions to those

provisions. This approach also is consistent with the approach used on several other recent

standards.

Comment 2: Commenter IV-D-28 stated that if any of the provisions that are borrowed

from other rules (i.e., restated rather than cross-referenced) are amended in the other rule, EPA

should reopen this rule and request public comment on making the same changes. Even if EPA

amends other rules that currently have no relationship to this rule (e.g., the P&R rules or the

Off-Site Waste and Recovery Operations rule), the commenter believes EPA should consider

whether the amendment might be beneficial in this rule as well, especially for the sake of

maintaining consistency.

Response: The EPA agrees with the commenter that subsequent amendments of other

rules may trigger a need to amend language from those other rules that has been incorporated in

this final rule. The decision, however, to amend any rule must be made on a case-by-case basis.

Comment 3: Because the rule references requirements from the HON that are periodic

(e.g., those for equipment leaks), commenter IV-D-28 believed there should be a statement as in

§ 63.100(k)(9) that specifies the meaning of periods of time.
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Response: The language from § 63.100(k)(9) has been added to the final rule.

20.4 RELATIONSHIP BETWEEN THE NOTIFICATION OF COMPLIANCE STATUS

REPORT AND TITLE V PERMITS

Comment: In the preamble to the proposed rule, EPA solicited comment on how to

incorporate the NOCS report into a facility’s title V permit and on the types of changes that

should trigger review actions under title V. Commenter IV-D-28 believes that questions

involving title V programs are best addressed under title V. The commenter noted that States

have developed their own operating permits programs, which differ from one another. These

differences may include whether and how to incorporate various requirements into a permit. As

a result, personnel administering the permit program will need to decide whether, and how, to

incorporate the Notification of Compliance Status report into permits. Commenter IV-G-05 does

not recommend incorporation by reference of the NOCS report into the title V permits without

also requiring the permitting authority to specify the date of the incorporation. The commenter

believes the types of changes that should trigger review actions under title V are any process

changes, or operating and compliance procedures, that increase the emissions from the facility.

Response: The EPA agrees with commenter IV-D-28 that questions involving title V are

best addressed under the title V program.

20.5 OMB REVIEW

Comment: Commenter IV-D-28 noted that it is unusual for Office of Management and

Budget (OMB) to classify a rule as a “significant regulatory action” for “novel legal or policy

issues.” Thus, the commenter is interested in understanding OMB’s concerns and requests that

EPA make the OMB document publicly available and solicit comment on issues raised by OMB.

Response: No OMB document explaining the rationale behind their classification

decision is available. All interagency exchanges, including review material exchanged with

OMB, are included in the rulemaking docket.

20.6 EDITORIAL CLARIFICATIONS

Comment: Several commenters (IV-D-16, IV-D-21, IV-D-28, and IV-D-29) identified

typographical errors and suggested minor editorial changes. 
20-5

Response: The commenters’ editorial remarks/issues and EPA’s responses are

summarized in Table 20-1.

20.7 COMMENT PERIOD

Comment: Commenter IV-D-28 was concerned that the public comment period, even

with the 30-day extension, which was helpful, was not long enough to ensure that all issues were 

identified. The commenter would prefer to deal with issues before the rule is promulgated

because making the provisions workable after promulgation can be time-consuming.

Response: The EPA believes sufficient time was provided for the public comment

period, especially in light of the 30-day extension. As part of the regulatory development

process, the Agency has a schedule to meet in promulgating the rule as well. The Agency will

continue to work with the industry and the public commenters in finalizing the rule and resolving

any issues prior to the promulgation date. 

20.8 SUPPORTIVE COMMENTS

Comment: Commenter IV-D-18 supported the rule as proposed and agrees with

identifying a broad range of control devices for compliance purposes. Commenter IV-G-01

supported EPA’s proposed exclusion of research and development (R&D) facilities from the

requirements of the rule. Commenter IV-G-05 endorses EPA’s approach for identifying PAI

processes subject to the standards because the EPA Form 3540-16 already identifies the affected

sources. However, the commenter cautions that a potential drawback of this approach is

uncertainty about the reliability of the data because it is self-reported. To lessen the effects of

this drawback, the commenter believes regulators can use permits and other information that

must be reported to comply with water or RCRA regulations to assist in identifying affected

sources.

Response: The EPA acknowledges and appreciates the comments. 
20-6

TABLE 20-1. EDITORIAL COMMENTS AND RESPONSES

Comment Commenter Response

In section 63.1360(d)(4)(i), change “from IV-D-28 The proposed language is consistent with

segregated sewers” to “managed in segregated the HON and has not been changed in the

sewers” final rule.

Use the term “storage vessel” rather than IV-D-28 Change made as suggested in comment.

“storage tank” for consistency with other

regulations

Paragraph (f)(4) in section 1360 is missing IV-D-16 and Paragraph (f)(5) in the proposed rule

IV-D-28 should have been numbered (f)(4). 

Add the word “or” between “foam” and IV-D-28 Change made as suggested in comment.

“liquid” in the definition of liquid-mounted seal

Reference to HON Table 8 compounds in the IV-D-16, This was an oversight in the proposed

definition of POD should be deleted IV-D-21, rule. Change made as suggested in

IV-D-28, and comment.

IV-D-29

Change “bottom receiver” to “bottoms IV-D-28 Change made as suggested in comment.

receiver” in section 63.1362(e)

Delete the words “the use of” from the first IV-D-28 Edited section to delete this phrase.

sentence of section 63.1364(c)(1)(v)

In section 63.1364(c)(2)(i)(A)(6), change IV-D-28 Change made as suggested in comment.

“...can be obtained from standard reference

texts.” to “...may be obtained from standard

references.”

In section 63.1364(c)(3)(i)(G), add units for the IV-D-28 Example units have been included.

gas-to-cloth ratio

In the last sentence of section 63.1364(c)(3)(ii), IV-D-28 Edited this section and deleted this

add “at or” before “below 20 ppmv” sentence.

In section 63.1365(f)(2)(iv), the reference to IV-D-16 Commenter is correct, but this provision

section 63.1362(f) should be changed to has been deleted from the final rule and

63.1362(g) replaced with cross reference to the

HON.

In section 63.1367(a)(1), change “within IV-D-28 Change made as suggested in comment.

150 calendar days of the compliance date” to

“no later than 150 after the compliance date”

In section 63.1367(a)(2), add “at least” before IV-D-28 Change made as suggested in comment,

“12 months” but submittal date changed from

12 months to 6 months before the

compliance date.

In section 63.1367(b)(1), replace the second IV-D-28 This provision has been deleted from the

comma with “and” final rule and replaced with cross

reference to the HON.

In Table 1, delete the word “replace” wherever IV-D-28 No changes made; several other rules use

it occurs and state what does or does not apply this language to describe changes.
TABLE 20.1 (continued)

Comment Commenter Response

20-7

The terms “HAP” and “organic HAP” are not IV-D-28 Checked entire rule and made changes. 

used consistently; check entire rule In some cases “total HAP” was added.

In the definition of “Group 1 storage tank,” IV-D-16 Commenter correctly identified

change cutoffs from 37 m to 38 m and replace typographical errors, but the cutoffs have 3 3

<76 m with $38 m to <76 m in the changed in the final rule. 3 3 3

applicability column of Table 2