United States Office of Air Quality EPA-453/R-99-002b

Environmental Protection Planning and Standards May 1999

Agency Research Triangle Park, NC 27711

Air

NATIONAL EMISSION STANDARDS FOR

HAZARDOUS AIR POLLUTANTS (NESHAP)

FOR THE POLYETHER POLYOLS

MANUFACTURING INDUSTRY:

SUMMARY OF PUBLIC COMMENTS AND

RESPONSES
EPA-453/R-99-002b

NATIONAL EMISSION STANDARDS FOR

HAZARDOUS AIR POLLUTANTS (NESHAP) FOR THE

POLYETHER POLYOLS MANUFACTURING INDUSTRY

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, NC 27711

May 1999
iii

Disclaimer

This report is issued by the Office of Air Quality Planning and Standards, U. S.

Environmental Protection Agency. Mention of trade names and/or commercial products is not

intended to constitute endorsement or recommendation for use. Copies of this report are

available free of charge to Federal employees, current contractors and grantees, and nonprofit

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

Protection Agency, Research Triangle Park, NC 27711, (919-541-2777) or, for a nominal fee,

from the National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia

22161, (703-487-4650).
iv
v

ENVIRONMENTAL PROTECTION AGENCY

National Emission Standards for Hazardous Air Pollutants for the 

Polyether Polyols Manufacturing Industry–

Background Information for Promulgated Standards

Prepared by:

Sally L. Shaver (Date)

Director, Emission Standards Division

U. S. Environmental Protection Agency

Research Triangle Park, NC 27711

1 The final National Emission Standards for Hazardous Air Pollutants (NESHAP) will regulate

emissions of hazardous air pollutants from polyether polyols manufacturing operations. Only

those operations that are part of major sources under section 112(d) of the Clean Air Act as

amended in 1990 will be regulated.

2 Copies of this document have been sent to the following Federal Departments: Labor, health

and Human Services, Defense, Transportation, Agriculture, Commerce, interior, and Energy;

the national Science Foundation; and the Council on environmental Quality; members of the

State and Territorial Air Pollution program Administrators; the Association of Local Air

Pollution Control Officials; EPA Regional Administrators; and other interested parties.

3 For additional information contact:

Mr. David Svendsgaard

Organic Chemicals Group (MD-13)

U. S. Environmental Protection Agency

Research Triangle Park, NC 27711

Telephone: (919) 541-2380

4. 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
vi

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

U. S. Environmental Protection Agency

Research Triangle Park, NC 27711

5. Electronic copies of this document may be obtained from the EPA’s OAR Technology

Transfer Network website (TTNWeb). 

The TTNWeb is a collection of related Web sites containing information about many areas of

air pollution science, technology, regulation, measurement, and prevention. The TTNWeb is

directly accessible from the Internet via the World Wide Web at the following address:

http//www.epa.gov/ttn
vii

TABLE OF CONTENTS

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

1.1 BACKGROUND ................................................ 1-1

1.2 SIGNIFICANT CHANGES SINCE PROPOSAL ........................ 1-3

1.2.1 Primary Product Determination .............................. 1-3

1.2.2 Definition of “Polyether Polyol” ............................. 1-5

1.2.3 The Definition of a “Process Vent” ........................... 1-5

1.2.4 Start-up and Shutdown Definitions ........................... 1-6

1.2.5 A Concentration Limit as an Alternative Epoxide Process Vent Emission

Limit for New Sources .................................... 1-6

1.2.6 Flares as a Reference Control Technology ...................... 1-8

1.2.7 Group Determination on an Individual Process Vent Basis for Nonepoxide

Emissions from Making or Altering the Product ................. 1-8

1.2.8 Possibility of Dual Controls for Nonepoxide HAPs for Making or

Modifying the Product ................................... 1-10

1.2.9 Worst-Case Testing Requirements .......................... 1-11

1.2.10 Engineering Calculations as an Alternative to Performance Testing . . 1-13

1.2.11 Revisions to the Test Method Requirement for Control Efficiency

Determination ......................................... 1-16

1.2.12 Flexibility of the Determination of a Site-specific Onset of Extended

Cookout .............................................. 1-17

1.2.13 Parameter Monitoring Excursion Definitions ................... 1-18

1.2.14 Start-up, Shutdown, and Malfunction Plan .................... 1-20

2.0 SUMMARY OF PUBLIC COMMENTS AND RESPONSES .................... 2-1

2.1 APPLICABILITY ................................................ 2-2

2.1.1 PMPUs Without Organic HAP .............................. 2-2

2.1.2 Definition of Affected Source ............................... 2-3

2.1.3 Processes Exempted from Affected Sources .................... 2-5

2.1.4 Necessity of Primary Product Redetermination .................. 2-6

2.1.5 Primary Product Determination and Applicability ................ 2-9

2.1.6 Primary Product Determination for Non-Flexible Operation Units ... 2-10

2.1.7 Applicability for Flexible Operation Units ..................... 2-10

2.1.8 Requirements for Flexible Operation Units when Producing Non-polyether

Polyols ............................................... 2-11

2.1.9 NonPMPUs that Produce Polyether Polyols ................... 2-13

2.1.10 Changes or Additions to Plant Sites ......................... 2-14

2.1.11 Applicability of this subpart except during periods of start-up, shutdown,

malfunction, or non-operation .............................. 2-17

2.1.12 Storage Tank Predominant Use ............................. 2-18

2.1.13 §63.1420(e)(5)(ii) ....................................... 2-19

2.1.14 Section 63.1420(c)(1) and (c)(8) Appear to be Duplicative . . 2-20

2.2 COMPLIANCE AND RELATIONSHIP TO OTHER RULES ........... 2-20
TABLE OF CONTENTS (continued)

viii

2.2.1 Time Periods ........................................... 2-20

2.2.2 Changes to the General Provisions .......................... 2-21

2.2.3 Cross-references with Other Subparts ........................ 2-22

2.2.4 Interfacing with Title V Operating Permit ..................... 2-24

2.2.5 Complexity of the Proposed Rule ........................... 2-25

2.3 DEFINITIONS ................................................ 2-26

2.3.1 Annual Average Concentration ............................. 2-26

2.3.2 Batch Cycle ........................................... 2-26

2.3.3 Cross-referencing of Definitions from Other Rules .............. 2-27

2.3.4 Epoxide .............................................. 2-31

2.3.5 Extended Cookout ...................................... 2-32

2.3.6 Impurity .............................................. 2-32

2.3.7 Make or Modify the Product ............................... 2-33

2.3.8 Non-epoxide HAP ...................................... 2-33

2.3.9 Organic HAP .......................................... 2-34

2.3.10 Override Definitions ..................................... 2-36

2.3.11 PMPU ............................................... 2-36

2.3.12 Polyether Polyol ........................................ 2-37

2.3.13 Pressure Decay Curve .................................... 2-39

2.3.14 Process ............................................... 2-40

2.3.15 Process Condenser ...................................... 2-41

2.3.16 Process Vent ........................................... 2-41

2.3.17 Product Class .......................................... 2-43

2.3.18 Purification ............................................ 2-45

2.3.19 Recovery Device ........................................ 2-45

2.3.20 “Start-up” and “Shutdown” ................................ 2-46

2.3.21 Storage Vessel ......................................... 2-48

2.3.22 Unit Operation ......................................... 2-48

2.4 PROCESS VENT CONTROL REQUIREMENTS ..................... 2-49

2.4.1 3 Percent Oxygen Correction .............................. 2-49

2.4.2 A Concentration Limit as an Alternative Process Vent Emission Limit

..................................................... 2-60

2.4.3 Basis for Outlet Concentration Testing as an Alternative Process Vent

Limit ................................................. 2-64

2.4.4 Group Determination for Nonepoxide HAP Process Vent Emissions on a

Vent-by-Vent Basis ...................................... 2-65

2.4.5 Relationship to Polymers and Resins I Changes ................. 2-71

2.4.6 Group Redetermination ................................... 2-72

2.4.7 Non-epoxide versus Epoxide Process Vent Emission Limits ....... 2-72

2.4.8 Alternative Emission Factor ............................... 2-73

2.4.9 Batch/Continuous Process Units versus Batch/Continuous Unit Operations

..................................................... 2-74
TABLE OF CONTENTS (continued)

ix

2.4.10 Controls for New Source Process Vent Emission Limits .......... 2-74

2.4.11 Calculation Methods for Emissions from Batch Operation Units .... 2-75

2.4.12 Continuous Unit Operations Group Determinations .............. 2-76

2.4.13 Summing the Values ..................................... 2-76

2.4.14 Flares as a Reference Control Technology for Existing and New Sources

..................................................... 2-77

2.4.15 Use of Multiple Compliance Methods ........................ 2-79

2.4.16 Uses and Emission Point Locations of Nonepoxides ............. 2-80

2.4.17 Possibility of Dual Controls For Nonepoxide HAPs from Making or

Modifying the Product ................................... 2-81

2.4.18 Clarification of "Schedule for Compliance" .................... 2-83

2.4.19 THE PMPU Exemption from Reporting ...................... 2-84

................................................................ 2-84

2.4.20 Clarification to Condenser Identity .......................... 2-85

2.4.21 Small Combustion Device Performance Testing ................ 2-86

2.4.22 Concentration Compliance ................................ 2-87

2.4.23 "Organic HAP" versus "HAP of Concern" ..................... 2-87

2.4.24 Rename "Product" as "Reactor Liquid" ....................... 2-88

2.4.25 §63.1425(e)(1)(i) ....................................... 2-89

2.5 EXTENDED COOKOUT AS A CONTROL OPTION ................... 2-90

2.5.1 In Support of the Inclusion of ECO .......................... 2-90

2.5.2 ECO Compliance Demonstration ........................... 2-90

2.5.3 Flexibility of the Determination of a Site-specific Onset of ECO .... 2-91

2.5.4 ECO Requirements for Monitoring .......................... 2-94

2.5.5 Accuracy "Buffer" for ECO Emissions Calculations ............. 2-96

2.5.6 Clarification of the Definition of "Emissions" in ECO Destruction

Efficiency Calculation .................................... 2-97

2.5.7 First Order for Epoxide Reactions ........................... 2-99

2.5.8 Update of Product Class List ............................... 2-99

2.5.9 Product Class Definition ................................. 2-100

2.5.10 Pressure Measurements .................................. 2-101

2.5.11 ECO Recordkeeping .................................... 2-101

2.6 MONITORING REQUIREMENTS FOR PROCESS VENTS .......... 2-102

2.6.1 Monitoring Requirement Exemptions for the Process Vent Requirements

.................................................... 2-102

2.6.2 Scrubber Monitoring Requirements ......................... 2-103

2.6.3 Monitoring of Multiple Absorbers .......................... 2-104

2.6.4 Alternative to §63.1429(a)(7) ............................. 2-104

2.6.5 Flow Indicator Specifications ............................. 2-105

2.7 GROUP DETERMINATION FOR NONEPOXIDE HAP EMISSIONS .... 2-106

2.7.1 Group Determination Records When the TRE Index is Between 1.0 and

4.0 .............................................. 2-106
TABLE OF CONTENTS (continued)

x

2.8 PROCESS VENT RECORDKEEPING AND REPORTING REQUIREMENTS

......................................................... 2-107

2.8.1 "Up-to-date" Process Vent Records ........................ 2-107

2.8.2 Flares Compliance Demonstration .......................... 2-107

2.8.3 Records for Start-ups, Shutdowns, Malfunctions, and Periods of Nonoperation ............................................ 2-108

2.8.4 Records Related to Group Determination .................... 2-109

2.8.5 Recordkeeping Exemption ............................... 2-110

2.8.6 Process Change Resulting in a Change in the TRE ............. 2-111

2.9 EMISSION FACTOR ........................................... 2-112

2.9.1 Emission Factor Plan .................................... 2-112

2.10 STORAGE VESSEL .......................................... 2-113

2.10.1 Storage Vessel Provisions ................................ 2-113

2.10.2 Previous Performance Testing of Storage Vessel Control Device . . 2-113

2.11 WASTEWATER PROVISIONS .................................. 2-114

2.11.1 Wastewater Cross-Referencing with the HON ................. 2-114

2.11.2 Definition of Wastewater in the Basis and Purpose for Proposed Standards

.................................................... 2-115

2.11.3 Classification of Wastewater Receiving Facilities ............... 2-116

2.11.4 Clarifying the Definition of Residuals ....................... 2-117

2.11.5 Wastewater Control Options .............................. 2-117

2.11.6 "Inprocess" Aqueous Streams Should not be Identified as Wastewater

Streams .............................................. 2-118

2.11.7 Selection of Compounds Subject to the Wastewater Provisions .... 2-119

2.11.8 Wastewater Nationwide Baseline Emissions Estimate: Steam Jet System’s

Condensate Estimate .................................... 2-120

2.11.9 Wastewater Nationwide Baseline Emissions Estimate: The Fraction

Emitted Factors Used ................................... 2-122

2.11.10 Inclusion of Biological Treatment as Wastewater Control Option

.............................................. 2-123

2.11.11 PEPO Chemical List Versus HON's Table 8 ............ 2-124

2.12 EQUIPMENT LEAK PROVISIONS .............................. 2-125

2.12.1 Method 21 for Equipment Leak Detection ................... 2-125

2.12.2 "Delay of Repair" Example in the Preamble ................... 2-125

2.12.3 Cost-Effective Alternatives to the HON LDAR ................ 2-126

2.12.4 De minimis Equipment Count ............................. 2-126

2.12.5 Applicability of Subpart I ................................ 2-127

2.12.6 Inclusion of Phase-in Option .............................. 2-127

2.12.7 Exemption for Heat Exchanger Units not Using HAP ........... 2-128

2.13 TESTING ................................................... 2-129
TABLE OF CONTENTS (continued)

xi

2.13.1 Consistency Between the Test Method Required in the Proposed Rule and

the Test Method Used to Establish the New Source Process Vent MACT

Floor ................................................ 2-129

2.13.2 Use of Method 25A Without Method 301 Validation ........... 2-129

2.13.3 Allow any Testing to Demonstrate Compliance ................ 2-131

2.13.4 Notice for Rescheduling of a Test .......................... 2-132

2.13.5 Engineering Calculations for Worst-case Requirements .... 2-133

2.13.6 Daily Averages versus Compliance ......................... 2-134

2.13.7 Method 1 or 1A ....................................... 2-135

2.13.8 Engineering Calculations as an Alternative Compliance Demonstration to

Performance Testing .................................... 2-136

2.13.9 Request for Exemption from Testing Multiple Similar Controls .... 2-139

2.13.10 Worst-Case Testing ............................... 2-140

2.13.11 Determination of Emission Profile for Worst-Case Testing . 2-144

2.14 PARAMETRIC MONITORING .................................. 2-145

2.14.1 Operating Permit Requirements ............................ 2-145

2.14.2 Average versus Maximum Value for Monitoring ............... 2-145

2.14.3 Compliance Determination ............................... 2-146

2.14.4 Excursion Provisions for Storage Vessels Exempt from Continuous

Monitoring, Process Vents from Batch Unit Operations, and Extended

Cookout ............................................. 2-150

2.14.5 Continuous Monitoring .................................. 2-151

2.14.6 Clarification to Text .................................... 2-153

2.15 GENERAL RECORDKEEPING AND REPORTING ................ 2-154

2.15.1 Elimination of Initial Notification .......................... 2-154

2.15.2 Provide Examples of Emission Points ....................... 2-154

2.15.3 Periodic Report ........................................ 2-155

2.15.4 Include all Records in One Section ......................... 2-155

2.15.5 Parametric Monitoring During Periods of Start-up, Shutdown or

Malfunction .......................................... 2-156

2.15.6 Exclusion of Monitoring Data from Daily Averaging ............ 2-161

2.15.7 Retention of Superseded Start-up, Shutdown, and Malfunction Plan

.................................................... 2-162

2.15.8 Exclusion to Continuous Recordkeeping Requirements .......... 2-162

2.15.9 Delete Redundancy in Recordkeeping Requirements ............ 2-163

2.15.10 Recordkeeping Waiver ............................ 2-163

2.15.11 "Document on Demand" ........................... 2-164

2.15.12 Notification of Compliance Status .................... 2-165

2.15.13 Addition of a Provision for Reporting Updates .......... 2-166

2.15.14 Revise Exemptions from Recordkeeping ............... 2-168

2.15.15 Recordkeeping Retention Revision ................... 2-169
TABLE OF CONTENTS (continued)

xii

2.15.16 Exclusion of Equipment Leaks to the Periodic Reporting

Requirements ................................... 2-170

2.15.17 Record of Preparation of Standards ................... 2-171

2.15.18 Periodic Reports ................................. 2-171

2.15.19 Predominant Use Reporting ......................... 2-173

2.15.20 Alternative Continuous Monitoring and Recordkeeping .... 2-174

2.15.21 Consolidation of Periodic Reporting .................. 2-174

2.15.22 Group Status Change Reporting ..................... 2-175

2.15.23 Excursions ...................................... 2-176

2.15.24 Alternative Continuous Monitoring for Storage Vessels .... 2-177

2.15.25 Cross-referencing in Reduced Recordkeeping ........... 2-178

2.15.26 Operating Permit Application ....................... 2-178

2.15.27 Manual Reading ................................. 2-179

2.15.28 "Any Other Information" in Sections 63.1439(e)(5)(i)(B) and

63.1439(e)(6)(iv)(B) .............................. 2-179

2.15.29 §63.1439(g)(3) .................................. 2-180

2.16 EDITORIAL ............................................... 2-181

2.16.1 "The Owner or Operator" Versus "Each Owner or Operator"

2-181

2.16.2 Section 63.1420(e)(3) ............................. 2-181

2.16.3 Section 63.1420(e)(5)(i) ................................. 2-182

2.16.4 Section 63.1420(e)(5)(iii) ................................ 2-182

2.16.5 Sections 63.1427(h)(1) and (h)(2) .......................... 2-183

2.16.6 Section 63.1427(1)(iv) .................................. 2-183

2.16.7 Section 63.1433(a)(9) ................................... 2-183

2.16.8 Section 63.1433(b) ..................................... 2-183

2.16.9 Section 63.1431(f)(1) ................................... 2-184

2.16.10 62 FR 46812, col. 3 ............................... 2-184

2.16.11 Section 63.1438(b)(3) ............................. 2-185

2.16.12 Heading in §63.1420(c) ............................ 2-185

2.16.13 Section 63.1420(c)(2) ............................. 2-185

2.16.14 Section 63.1420(d) ............................... 2-186

2.16.15 Section 63.1420(e)(1) ............................. 2-186

2.16.16 Section 63.1422(d)(2)(iv) and (d)(5) .................. 2-186

2.16.17 Section 63.1420(f)(7)(i) ............................ 2-187

2.16.18 Section 63.1424(a) ............................... 2-187

2.16.19 Section 63.1425(c)(4)(i) ........................... 2-187

2.16.20 Section 63.1426(c) ............................... 2-188

2.16.21 Section 63.1426(c)(1)(i)(C)(ii), (c)(3)(ii), and (e)(1) ...... 2-188

2.16.22 Section 63.1426(e)(1) ............................. 2-189

2.16.23 "Pressure Decline Curve" Versus "Pressure Decay Curve" . . 2-190

2.16.24 Section 63.1427(l)(3)(ii) ........................... 2-190
TABLE OF CONTENTS (continued)

xiii

2.16.25 Section 63.1428(c) ............................... 2-190

2.16.26 Section 63.1435(d) ............................... 2-191

2.16.27 Section 63.1439(b) ............................... 2-191

2.16.28 Section 63.1439(e)(6)(iii)(A) ........................ 2-192

2.16.29 Section 63.1439(e)(6)(iii)(D)(1) and (f)(3) ............. 2-192

2.16.30 Section 63.1426(c)(4)(iv), (c), and (c)(1)(i)(A) .......... 2-193

2.16.31 Equation 9 ...................................... 2-193

2.16.32 Section 63.1425(e)(2)(i) ........................... 2-194

2.16.33 Section 63.1425(f) ................................ 2-194

2.16.34 Section 63.1429(d)(3) ............................. 2-195

2.16.35 Section 63.1439(e)(6)(v) ........................... 2-195

2.16.36 Section 63.1439(h)(1) ............................. 2-195

2.16.37 Section 63.1427 ................................. 2-196

2.16.38 Section 63.1439(e)(5)(ii)(D) ........................ 2-196

2.16.39 Section 63.1439(b) ............................... 2-197

2.16.40 Actual Date Versus "Date of Promulgation" ............ 2-198

2.16.41 Changes to Several Equations ....................... 2-198

2.16.42 Section 63.1420(h)(3) ............................. 2-199

2.16.43 Table 1 ........................................ 2-199

2.16.44 Table l ......................................... 2-200

2.16.45 Table 2 ........................................ 2-200

2.16.46 Table 2 ........................................ 2-201

2.16.47 Table 4 ........................................ 2-201

2.16.48 Table 5 ........................................ 2-201

2.17 LEGAL CONSIDERATIONS .................................. 2-202

2.17.1 Executive Order 12866 .................................. 2-202
1-1

1.0 SUMMARY

1.1 BACKGROUND

On September 4, 1997 (62 FR 46804), the United States

Environmental Protection Agency proposed National Emission

Standards for Hazardous Air Pollutants (NESHAP) for Polyether

Polyols Production under Section 112(d) of the Act.

Public comments were requested on the proposed standard and

comment letters were received from industry representatives and

governmental entities. A total of 13 comment letters were

received. Table 1-1 presents a listing of all persons that

submitted written comments, their affiliation, and their docket

item number. A public hearing was not requested.

The written comments that were submitted on the proposed

rule have been summarized, and responses to the comments are

included in the following sections. This summary of comments and

responses serves as the basis for revisions made to the NESHAP

between proposal and promulgation.
1-2

TABLE 1-1. LIST OF COMMENTERS ON PROPOSED NATIONAL EMISSION

 STANDARDS FOR HAZARDOUS AIR POLLUTANTS

Air Docket A-96-38 Commenter and affiliation

Item Number

IV-D-01 T.A. Threet, Counsel, The Dow Chemical Company,

Midland, MI

IV-D-02 M. Wax, Deputy Director, The Institute of Clean

Air Companies, Washington, D.C.

IV-D-03 J.P. Keigher, Responsible Care Manager, Olin

Chemicals Group, Brandenburg, KY

IV-D-04 D.W. Gustafson, EH&S Regulatory Management; T.A.

Threet, Legal, The Dow Chemical Company, Midland,

MI

IV-D-05 M.A. Healey, Director, Federal Environment and

Transportation Issues, The Society of the Plastics

Industry, Inc., Washington, D.C.

IV-D-06 M. Manning, Corporate Ecology & Safety, BASF

Corporation, Enka, NC

IV-D-07 J.C. Hovious, Assistant Director, Environmental

Affairs, Union Carbide Corporation, Danbury, CT

IV-D-08 M.L. Mullins, Vice President, Regulatory Affairs,

Chemical Manufacturers Association, Arlington, VA

IV-D-09 J.A. Dege, Jr., Manager - Air Programs, DuPont SHE

Excellence Center, Wilmington, DE

IV-D-10 D.C. Boyle, Director, Environmental, Health and

Safety, ARCO Chemical Company

IV-D-11 D.C. Boyle, Director, Environmental, Health &

Safety, ARCO Chemical Company, Newtown Square, PA

IV-G-01 C.F. Johnston, Environmental Manager, ICI

Chemicals & Polymers, New Castle, DE

IV-G-02 J.C. Hovious, Assistant Director, Environmental

Affairs, Union Carbide Corp, Supplemental

Comments, Danbury, CT
1-3

1.2 SIGNIFICANT CHANGES SINCE PROPOSAL

In response to comments received on the proposed standards,

several changes have been made to the final rule. A summary of

the substantive changes made since the proposal in response to

comments is provided in the following sections. Additional

information on the final rule is contained in the docket for this

rule (Docket A-96-38).

1.2.1 Primary Product Determination

One commenter expressed confusion over aspects of the

primary product determination in the proposed rule, particularly

the provision that specified how a non-PMPU could become a PMPU

after the initial determination based on actual production. The

EPA agreed that this portion of the proposed primary product

provisions needed clarification. In fact, the EPA conducted an

overall review of the proposed primary product provisions, and

concluded that several structural and clarifying changes were

needed. In addition, the EPA noted some potential situations

that could occur that were not addressed in the proposed

provisions.

The specific concern raised by the commenter was addressed

by clearly stipulating how owners or operators of non-PMPUs are

to determine whether they have become subject to the rule after

the initial primary product determination. The final rule

specifies that non-PMPUs that have produced polyether polyols in

the past five years are to annually re-determine the primary

product using actual production values. The rule also specifies

how a non-PMPU process unit is to determine the primary product

if it has not produced polyether polyols in the past five years,

but plans to produce polyether polyols in the future.

The proposed provisions required that initial primary

product determination be based on a five-year prediction of

anticipated production by the owner or operator. The EPA is

aware that, in some instances, the owner or operator may not be

able to make such a prediction. Clarifications and/or revisions
1-4

were made to the primary product provisions to address this

situation. First, in the initial determination, the time frame

for which production must be anticipated for new process units

was changed to one year. Also, provisions were added for owners

or operators that cannot determine the primary product based on

anticipated five-year (or one-year) production. In such

situations, the process unit is designated as a PMPU and is

subject to the existing source provisions of subpart PPP, if

polyether polyols have been produced in an existing process unit

for 5 percent or greater of the time since September 4, 1997. 

For new process units, if polyether polyols will be produced at

any time during the first year of production, then the unit is a

PMPU and subject to the new source provisions of subpart PPP.

In addition to the provisions discussed above that specify

how non-PMPUs are to determine if they become PMPUs and subject

to subpart PPP, the EPA has also clarified and expanded the

provisions that specify how the PMPU designation can be removed

from a process unit. The first case, which is retained from the

proposed rule, is where production of polyether polyols ceases

and the owner or operator does not anticipate the production of

polyether polyols in the future. Also, the EPA has added

provisions that specify procedures for a primary product reevaluation based on actual production. If an owner or operator

of a PMPU finds that another product has been produced for a

greater amount of time than polyether polyols over a specified

time period (previous five years or since beginning the

production of polyether polyols), then the PMPU designation would

be removed provided that production of the “new” primary product

must make the process unit subject to another part 63 NESHAP. If

the new primary product is not subject to another part 63 NESHAP

and polyether polyols continue to be produced, the process unit

continues to be classified as a PMPU and continues to be subject

to subpart PPP.
1-5

The EPA has also added provisions addressing the

determination of the primary product in situations where two or

more products are produced simultaneously. Also, clarifications

were made in the reporting and recordkeeping requirements

associated with the primary product determination.

1.2.2 Definition of “Polyether Polyol”

In the proposed rule a “Polyether Polyol” was defined as "a

compound formed through the polymerization of ethylene oxide (EO)

or propylene oxide (PO) or other cyclic ethers with compounds

having one or more reactive hydrogens (i.e., a hydrogen atom

bonded to nitrogen, oxygen, phosphorus, sulfur, etc.) to form

polyethers. This definition excludes materials regulated under

the HON, such as glycols and glycol ethers."

One commenter requested that EPA revise the definition of

"polyether polyol" to clarify that the production of typical

alkanolamines, which lack repeating ether units, is not regulated

under subpart PPP. Another commenter explained that hydroxy

ethyl cellulose is formed through the reaction of EO on cellulose

polymer molecules. This commenter requested that the EPA clarify

whether hydroxy ethyl cellulose manufacturing is included or

excluded from the definition of “polyether polyol.” 

The EPA has revised the definition of "polyether polyol" in

the final rule addressing both these issues by excluding the

production of hydroxy ethyl cellulose and by specifying that a

polyether must have more than two ether bonds.

1.2.3 The Definition of a “Process Vent”

The definition of “process vent” in the proposed rule did

not include any cutoffs based on the flow or HAP concentration of

the process vent. One commenter was concerned that the

definition of "process vent" did not have a de minimis cutoff, as

does the definition of “process vent” in the HON. The cutoff

suggested by the commenter (0.005 weight-percent total organic

HAP) has been incorporated into the final definition of a process

vent, for process vent from continuous unit operations. This
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decision was based on the fact that the EPA considers it to be

impractical to impose requirements for process vent streams with

such low HAP concentrations (less than 0.005 weight percent

organic HAP). For similar reasons, a de minimis cutoff for

process vents from batch unit operations was also added in the

final rule. In the Polymers and Resins I and IV NESHAP, the

batch process vent definition contains a de minimis cutoff of 225

kg/yr uncontrolled HAP emissions. The EPA believes that this

level is also an appropriate de minimis level for process vents

from batch unit operations in the polyether polyols industry.

1.2.4 Start-up and Shutdown Definitions

One commenter noted that the definitions of "start-up" and

"shutdown" in the proposed rule were not parallel. The

definitions were revised in the final rule.

1.2.5 A Concentration Limit as an Alternative Epoxide Process

Vent Emission Limit for New Sources

The proposed rule did not include a concentration limit as

an alternative epoxide process vent emission limit for new

sources. The preamble to the proposed rule solicited comments on

this subject, to which four commenters responded. All four

recommended a 20 ppmv alternative concentration limit. The

commenters indicated that the preambles for the New Source

Performance Standard for VOC Emissions from Synthetic Organic

Chemical Manufacturing Industry (SOCMI) Distillation Operations

(40 CFR 60, subpart NNN), and the HON (40 CFR 63, subpart G)

provided rationales for a 20 ppmv limitation that also are

applicable to the polyether polyols rule.

In subpart NNN's preamble (48 FR 48932, October 21, 1983),

the EPA stated that the outlet concentration of 20 ppmv was

established based on kinetic calculations of incinerators. It

was demonstrated that, at a given temperature and residence time,

a stream with a low inlet concentration could not demonstrate an

outlet concentration below 20 ppmv. In the preamble to the

proposed amendments to the HON (61 FR 43698, August 26, 1996),
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the EPA expanded the application of this lower bound

concentration performance standard to control/recovery devices

other than incinerators. In the HON preamble, the EPA explained

that recovery devices are designed to typically reduce emissions

to the same outlet concentration level given a relatively wide

range of inlet concentrations. When the inlet concentration is

substantially below the design maximum leading conditions (and

begins to approach the residual level in the outlet stream) the

recovery device efficiency will decrease. 

Therefore, the final rule contains an alternative

concentration limit of 20 ppmv, which is measured at the outlet

of the combustion, recovery, or recapture device. This

alternative provides owners or operators of affected sources with

the ability to comply with the standard when the inlet

concentration to the combustion, recovery, or recapture device

drops below the point where optimum control efficiency can be

achieved, and when it is not feasible to require optimum percent

reduction levels to be met. This rationale for allowing the 20

ppmv alternative is applicable for both new and existing sources,

even though the new source percent reduction limitation is more

stringent than the existing source percent reduction limitation. 

Therefore, the final rule allows this alternative for both new

and existing sources.

Another commenter advocated that the alternative 20 ppmv

concentration limit should apply more broadly to process vents

that do not utilize a combustion, recovery, or recapture device

to reduce epoxide emissions. The examples provided by the

commenter included vents from equipment practicing a very long

extended cookout or vents from equipment where the epoxide

content is very low and emissions are very small. 

The EPA understands that the outlet concentration after

extended cookout (ECO) may be as low as that after a combustion,

recovery, or recapture device. However, this is not based on

technological limitations of ECO, as is the basis for the 20 ppmv
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concentration limit for combustion, recovery, and recapture

devices. Therefore, the EPA believes that allowing the 20 ppmv

concentration limit for ECO is not appropriate.

Further, the EPA does not believe that it is appropriate to

use this alternative concentration requirement as a de minimis

cutoff for vents where the epoxide content is very low and

emissions are very small. The EPA believes that the HAP

concentration and emission de minimis cutoffs in definition of

the process vent (discussed above in Section 1.2.3) adequately

address these vents.

Finally, the proposed existing source concentration limit

was 20 ppmv of total epoxides. Other rules, such as the HON,

allow the option of determining outlet concentration limits on a

TOC basis. In many instances in the polyether polyols industry,

all the TOC in the emission stream will be epoxides, making the

TOC and epoxide concentration equivalent. In fact, if there were

other TOC in the stream, compliance with a 20 ppmv TOC limit

would mean that the epoxide concentration would necessarily be

less than 20 ppmv. For these reasons, the EPA believes that

having the alternative concentration limits based on total

epoxides or TOC is appropriate for this rule. As discussed later

in Section 1.2.11, the EPA decided to allow Method 25A (which is

designed to measure TOC) to determine compliance with the

alternative concentration limits.

1.2.6 Flares as a Reference Control Technology

Two commenters requested that the EPA allow flares as a

reference control technology for process vents at existing and

new sources. The EPA agreed with the commenters that flares are

an acceptable reference control technology for situations where

the required organic HAP emission reduction is 98 percent or

less. The final rule was revised to allow flares as a reference

control technology for epoxide process vent emissions at existing

sources, for Group 1 nonepoxide HAP process vent emissions at new

and existing sources, and for nonepoxide HAP process vent
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emissions from catalyst extraction at new and existing sources. 

However, the data presented by the commenters do not support a

destruction efficiency of 99.9 percent for flares combusting EO

and PO, which is the equivalent percent reduction efficiency for

the epoxide process vent limitation for new sources. Therefore,

the EPA cannot allow flares as a reference control technology for

epoxide process vent emissions at new sources. 

1.2.7 Group Determination on an Individual Process Vent Basis

for Nonepoxide Emissions from Making or Altering the

Product

At proposal, the rule required "group" determinations (to

determine whether control is required) for nonepoxide process

vent emissions from making or modifying the product be made for

the combination of all the associated process vents in the PMPU. 

Two commenters raised the point that the equations and other

criteria for deciding whether a vent is Group 1 or Group 2 were

based on cost-effectiveness decisions of controlling individual

process vents, and were borrowed from other rules that apply them

on an individual vent basis. The commenters requested that

owners or operators have the option of making the group

determinations for nonepoxide process vents on a vent-by-vent

basis, rather than being required to do the group determination

for the combination of all process vents.

The EPA agrees with the statement that the Group 1 criteria

is essentially a cost-effectiveness decision. The EPA also

agrees that the group determination criteria in subpart PPP were

borrowed from other MACT standards, specifically the HON (for

process vents from continuous unit operations) and Polymers and

Resins I and IV (for process vents from batch unit operations). 

Finally, the EPA recognizes that in all three of the rules cited

above, the group determination has been applied to individual

process vents.

The EPA agrees that the total resource effectiveness (TRE)

index approach was developed for, and has been applied to,
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individual vents. The EPA further agrees that applying the TRE

approach to the combination of process vents from continuous unit

operations in a PMPU is not appropriate without conducting an

analysis to validate the equations for the combination of vents,

or to develop new equations. Rather than take this approach, the

EPA decided to apply the Group 1 criteria for process vents from

continuous unit operations that use nonepoxide organic HAP to

make or modify the product to individual process vents. 

For process vents from batch unit operations that use

nonepoxide organic HAP to make or modify the product, the Group 1

equations are the same equations employed in the Polymers and

Resins I and IV MACT standards (40 CFR 63, subparts U and JJJ,

respectively). The EPA agrees with the commenters that in the

polymers and resins standards, the Group criteria are applied to

individual vents. However, unlike the TRE for process vents from

continuous unit operations, the group determination approach that

is used in subparts U, JJJ, and PPP, was originally developed to

be used for either individual vents or the combination of vents.

The original source of the batch vent group determination

approach is the EPA document "Control of Volatile Organic

Compound Emissions From Batch Processes - Alternative Control

Techniques Information Document" (EPA-453/R-94-020), i.e., the

Batch ACT. On page 7-5 of this document, the EPA states “The

control option requirements presented in Chapter 6 apply to (1)

individual batch VOC process vents to which the annual mass

emissions and average flowrate cutoffs are applied directly, and

(2) aggregated VOC process vents for which a singular annual mass

emission total and average flowrate cutoff value is calculated

and for which the option is applied across an aggregate of

sources.” Therefore, for process vents from batch unit

operations, the EPA disagrees with the statements that the group

determination equations are being used “in a totally different

context” and that there is no supporting rationale for using

them. The final rule retains the requirement that the Group
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criteria be applied to the nonepoxide organic HAP emissions from

the combination of process vents from batch unit operations

associated with the use of nonepoxide organic HAP to make or

modify the product.

1.2.8 Possibility of Dual Controls for Nonepoxide HAPs for

Making or Modifying the Product

The proposed rule required group determinations the

nonepoxide HAP process vent emissions from making or modifying

the product. One commenter pointed out that the proposed rule

was not clear about when and where to make this group

determination. The commenter also noted that a process vent that

uses a control technique for epoxides only (e.g., a scrubber or

ECO) would require a second control technique for the nonepoxide

HAP emissions.

The EPA considered the commenter’s points and the options

suggested by the commenter. The final rule requires that the

group determination for nonepoxide HAP emissions be made after

the stream has been controlled for the epoxide emissions. The

EPA believes that this approach addresses the situation regarding

the possibility of dual control. If the epoxide control device

also reduces nonepoxide emissions, then that control would impact

whether the vent (or group of batch vents) is Group 1. 

Therefore, control of nonepoxide emissions along with the

epoxides will impact whether controls are required at all. If

the vent (or group of vents) still has sufficient nonepoxide

organic HAP emissions after the epoxide control device to satisfy

the Group 1 criteria, the EPA does not believe it is unreasonable

to require an additional control device to achieve the specified

percent reduction of the nonepoxide emissions.

1.2.9 Worst-Case Testing Requirements

The proposed rule required that performance tests for

process vents be conducted during worst-case operating conditions

for the process. Four commenters requested that this requirement

be deleted from the rule.
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Worst-case testing requirements were not deleted from the

final rule, but were revised. The EPA’s reason for requiring

compliance testing under worst case conditions is so that the

reduction efficiency of the control device is documented under

the most challenging conditions for that control device,

especially since commenters noted how difficult it is to

represent a typical venting episode. The phrase "worst-case" in

the proposed rule referred to the operating conditions of the

process (or PMPU). The worst-case testing requirement has been

revised to require testing during the worst-case conditions with

respect to the combustion, recovery, or recapture (i.e., control)

device.

Presumably, the control device should function as well or

better under conditions that are not as challenging. By revising

the rule to require testing during the worst-case conditions with

respect to the control device, continuous monitoring of operating

parameters established during the test provides a reasonable

measure of continuous compliance with the efficiency requirement

under all conditions.

The commenters asserted that there is no obvious

technological difference that would require a different approach

to performance testing in this rule as from other regulations

have allowed performance tests during representative operating

conditions. The EPA disagrees with the commenters’ rationale. 

The EPA believes that there are obvious technological differences

from the polyether polyols industry to industries previously

regulated (particularly SOCMI type industries) since polyether

polyols are produced on a batch basis. There is much more

variance in the process vent parameters (i.e., flow and

concentration) for process vent streams from batch unit

operations, compared to process vents from continuous unit

operations. In fact, this point was stressed by commenters. The

EPA believes that it is more appropriate to compare the

requirements of this rule with other rules that also regulate
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industries that operate on a batch basis. For this rule the EPA

not only compared the worst-case testing conditions with other

rules regulating batch processes, but adopted similar language to

that which is used in the Pharmaceutical Production NESHAP (40

CFR 63, subpart GGG).

The EPA would like to clarify a misconception related to

these worst-case testing provisions. It is not the intent that

production schedules be significantly altered, or that

impractical scenarios be created for testing that would never

occur in actual production. In other words, the EPA intends that

testing be conducted for the worst-case situation that can

reasonably be expected to occur during normal production. In

order to clarify this intent, the EPA has added language in

§63.1438, the general testing section of the rule. This new

language specifies that absolute worst case testing conditions

does not include situations that could cause damage to equipment,

situations that necessitate that the owner or operator make

product that does not meet an existing specification for sale to

a customer, or situations that necessitate that the owner or

operator make product in excess of demand. 

The added language in §63.1438 also specifies the time

period in which the worst-case conditions are to be determined. 

This time period is either the 6-month period that ends 2 months

before the Notification of Compliance Status is due, or the 6-

month period that begins 3 months before the performance test and

ends 3 months after the performance test. By limiting the worstcase conditions to one of these 6-month periods, the rule

eliminates the need for an owner or operator to consider endless

possible production scenarios, and allows them to focus on those

production scenarios in the 6-month period selected by the owner

or operator.

In conclusion, the EPA believes that requiring that

performance tests for process vents from batch unit operations

during absolute worst-case conditions is necessary to ensure that
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the emission limitations in the rule are achieved. The EPA also

believes that, with the modifications to the rule made after

proposal, that the worst case provisions are reasonable and

workable for the polyether polyols industry.

1.2.10 Engineering Calculations as an Alternative to

Performance Testing

Three commenters voiced concern over the feasibility,

accuracy, expense, and safety of measuring emissions from process

vents from batch unit operations. The commenters stated that a

performance test on these short duration, variable vents is

likely to be very inaccurate and potentially dangerous. Two of

the commenters recommended that a material balance based on

common engineering calculations should be allowed in the final

rule as a compliance demonstration option. The commenters stated

that engineering calculations would provide a more accurate, less

costly, and significantly safer means to verify compliance.

The EPA recognizes that there are issues related to the

feasibility, accuracy, and expense of testing process vents from

batch unit operations. The EPA would refer readers to Section

7.3 of EPA’s “Control of Volatile Organic Compound Emissions from

Batch Processes - Alternative Control Techniques Information

Document” EPA-453/R-94-020 for a detailed discussion of these

issues. However, the EPA does believe that accurate emission

tests can be conducted for these process vents.

One reason that the EPA has historically required

performance testing for control devices that reduce emissions

from process vents, when engineering analyses is allowed for

other emission sources (such as storage vessels), is that

emissions from process vents are typically significantly larger

than those from other emission sources. When emissions are

larger, the EPA believes that it is important that the

effectiveness of the control device be accurately determined by a

performance test.
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Given that the magnitude of the emissions was a part of the

basis for requiring performance tests, the EPA believes that it

is reasonable to allow an alternative to performance testing for

a process vent control device if emissions being routed to the

device are comparable to the emissions that would be vented to

control devices for other emission sources for which performance

tests are not required. Therefore, the EPA decided that

engineering assessments could be allowed in lieu of performance

testing for “small” control devices that reduce HAP emissions

from process vents. For the Pharmaceutical Production NESHAP,

the EPA also determined that it was appropriate to allow

engineering calculations as an alternative to performance testing

for small control devices, where a small control device is

defined as one with uncontrolled annual HAP emissions of less

than 10 tons per year. The EPA believes that this level of

uncontrolled emissions is also appropriate to define a small

control device for the polyether polyols industry. Therefore,

the final rule allows the use of a design evaluation instead of a

performance test if the control device receives less than 10 tons

per year uncontrolled emissions from one or more PMPUs.

The exemption from performance testing for small control

devices discussed above should help to alleviate some of the

concerns raised by the commenters. Many of the concerns related

to the feasibility, accuracy, and expense of testing these batch

vents are due to the short duration, variable nature of batch

venting episodes. The EPA believes that if a control device

receives more than 10 tons per year of uncontrolled HAP

emissions, it is likely that the vent streams being routed to the

device are of longer duration and less variable, thus making it

easier to conduct the performance test.

However, the EPA also recognizes that the small control

device exemption will not totally eliminate the concerns raised

by the commenters. Therefore, the EPA made other changes to the

testing requirements to address potential problems related to the
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testing of batch process vents, which are briefly discussed

below. 

Since batch emission episodes can be less than one hour, the

rule was changed to specify that test runs be conducted for the

complete duration of the batch venting episode or one hour,

whichever is less. Other references to one-hour periods were

also removed.

The proposed rule required the use of Method 1 or 1A to

select sampling sites. Commenters claimed that, in many

instances, neither method would be appropriate for the batch vent

streams. The rule was restructured by separating the paragraph

addressing the use of Method 1 or 1A for sample or velocity

traverses from the paragraphs specifying the sampling site

location. In other words, if the owner or operator conducts a

sample or velocity traverse, the final rule requires that Method

1 or 1A be used. However, it does not require that these methods

be used to select sampling sites.

With regard to the safety issue, the final rule states that,

in cases where it is imperative to limit any leakage of emissions

into the work atmosphere, a sampling port with a double seal

should be installed so that the probe can be inserted and removed

without any leakage of exhaust gas into the work atmosphere. 

Further, the final rule requires that permanent sampling ports be

installed at the inlet to the control device during a period when

it is most convenient (or least disruptive) to shut the process

down (e.g., during a scheduled maintenance outage). In addition

to these specific requirements, a general requirement was added

that allows owners or operators to eliminate potential testing

scenarios if the test could create a situation which could cause

plant or testing personnel to be subject to unsafe conditions.

In conclusion, the EPA acknowledges that issues exist with

regard to the testing of emissions from batch process units. 

Changes have been made to the final rule to address these issues. 

However, the Agency maintains that numerous other industries that
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utilize batch processes are regulated by MACT standards, and are

able to conduct performance tests. The EPA believes that the

commenters did not provide sufficient rationale why the polyether

polyols industry presents unique testing problems that are not

present in these other industries that utilize batch processes. 

Therefore, the final rule requires that control devices that

receive more than 10 tons per year of uncontrolled organic HAP

emissions conduct tests to demonstrate control device

performance.

1.2.11 Revisions to the Test Method Requirement for Control

Efficiency Determination

The proposed rule required Test Method 18, or any other

method or data that has been validated according to Method 301

for control efficiency determinations. Three commenters noted

that this requirement was inconsistent with the test methods used

by the facility whose data established the new source MACT floor

for epoxide process vent emissions (Method 25A was used). These

commenters discussed the expense of Method 301 validation, and

noted that the proposed rule relied on Method 25A in other parts

of the rule (for wastewater), and that other rules (such as the

Polymers and Resins IV rule) allowed Method 25A without Method

301 validation. 

The EPA agrees that allowing of the use of Method 25A would

provide more flexibility, and potentially provide the opportunity

for less costly testing. However, the EPA believes that Method

25A should be used only after an accurate response factor has

been determined. The importance of calibrating a flame

ionization detector (FID) reading obtained using Method 25A with

respect to a certain compound (adjustment by response factor)

depends on how the Method will be used to demonstrate compliance

with the standard. In general, the EPA believes that an accurate

response factor is necessary in cases where Method 25A is used to

demonstrate control efficiency across a device where the

composition of the stream may change, or in situations where
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multiple components, including non-HAP VOCs, are present. 

Because the relative proportion of organic compounds may change

across the control device, appropriate response factors are

needed to accurately quantify TOC at the inlet and outlet of a

control device. In addition, the EPA believes that owners and

operators should have the opportunity to demonstrate compliance

at the outlet of a control device by measuring 20 ppmv TOC or

less. Therefore, the final rule does allow the use of Method 25A

under certain conditions. The following describes the choices of

test methods allowed in the final rule: (1) Method 18 to

determine HAP concentration in any control device efficiency

determination; (2) Method 25 to determine total gaseous

nonmethane organic concentration for control efficiency

determinations in combustion devices; (3) Method 25A to determine

the HAP or TOC concentration for control device efficiency

determinations under the conditions specified in Method 25 of

appendix A of part 60 for direct measurement of an effluent with

a flame ionization detector, or in demonstrating compliance with

the 20 ppmv TOC outlet standard.

1.2.12 Flexibility of the Determination of a Site-specific

Onset of Extended Cookout

The proposed rule defined the onset of the extended cookout

(ECO) as the point when the epoxide concentration in the liquid

is equal to 25 percent of the concentration of epoxide in the

liquid at the end of the epoxide feed. In addition to using this

"default" definition of the ECO onset, the proposed rule allowed

owners and operators the option of defining the onset of the ECO

for their specific process, at a point other than when the

reactor epoxide partial pressure equals 25 percent of the reactor

partial pressure at the end of the epoxide feed. The factors in

setting a site-specific ECO onset were the profit variable margin

(the difference between variable costs (raw materials and energy)

of the product) and the cost of the raw material. One commenter

objected to allowing the establishment of a site-specific ECO
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onset based on economics, stating that economics can be

subjective, making it easy to demonstrate a 98-percent emission

reduction. 

A late submittal from one commenter refuted the first

commenter’s argument that the onset of ECO is subjective, stating

that one of the pieces of economic information, the price of the

raw material, comes from the Chemical Market Reporter. However,

the other variable in defining the onset of ECO, the product

variable margin and the selling price, was the variable that

provoked the original commenter’s concern. In fact, the

commenter providing the late comment stated that the product

variable margin has "a much stronger correlation between product

profitability and the economic onset of ECO." 

Due to the subjectivity of the product variable margin, and

the strong correlation between the product variable margin and

the ECO onset, the EPA agreed with the first commenter. 

Therefore, the EPA revised the final rule, and the determination

of a site-specific ECO onset is not allowed.

1.2.13 Parameter Monitoring Excursion Definitions

In reviewing the sections associated with parameter

monitoring excursions as a result of public comments, the EPA

decided to restructure and expand these provisions in order to

simplify and clarify these provisions in subpart PPP. 

Basically, there are two ways an excursion can occur. The

first is if the average parameter value measured is above a

maximum, or below a minimum, established value. The second is if

insufficient monitoring data are collected. The proposed rule

had a definition of an excursion for each of these situations. 

However, the EPA realized that the proposed definitions of

excursions were not well suited to emission points where

intermittent venting episodes occur, such as storage vessels that

vent only when being filled and process vents from batch unit
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operations. Therefore, paragraphs were added to the final rule

to define excursions for these situations. 

Also, the EPA realized that while excursions for owners or

operators using extended cookout to comply with the epoxide

emission limitations were defined in the extended cookout section

of the rule, a reference to those definitions was needed in the

parameter monitoring levels and excursions section (§63.1438). 

Therefore, another paragraph was added referring to the excursion

definitions for ECO.

With regard to calculating averages, §63.1439(d)(7) of the

final rule specifies that monitoring data collected during

periods of monitoring system breakdowns, repairs, calibration

checks, and zero (low-level) and high-level adjustments; startups; shutdowns; malfunctions; and periods of non-operation of the

affected source that result in the cessation of emissions to

which the monitoring applies are not to be included when

calculating any average.

Language has also been added to §63.1438(f) to clarify when

monitoring data are insufficient. An excursion due to

insufficient monitoring data occurs if measured values are

unavailable for a specified percentage of time the control device

is in operation. First, the rule now clarifies the situations

that cause measured values to be unavailable: monitoring system

breakdowns, repairs, calibration checks, or zero (low-level) and

high-level adjustments. Second, the final rule clarifies that

periods of start-ups; shutdowns; malfunctions; and periods of

non-operation of the affected source that result in the cessation

of emissions to which the monitoring applies are not to be

included in defining the period of control device operation.

Finally, commenters requested that the EPA clarify the

appropriate use of parameter monitoring data for enforcement

purposes. Paragraph §63.1438(e) of the final rule has been

rewritten to add specificity regarding what the owner or operator

is out of compliance with when an excursion occurs (that is not
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an excused excursion). If an organic monitoring device is used

to monitor HAP or TOC concentration at the outlet of a recovery

or recapture device, the final rule clarifies that each excursion

where the daily average value of monitored parameters is above

the maximum, or below the minimum established parameter level,

represents a violation of the emission limit. Similarly, an

excursion where the daily average temperature is above the

maximum established temperature for a condenser represents a

violation of the emission limit. Other excursions where average

values are above the maximum, or below the minimum established

parameters represent violations of the operating limit, rather

than violations of the emission limit. Also, excursions due to

insufficient monitoring data are violations of the operating

limit.

1.2.14 Start-up, Shutdown, and Malfunction Plan

The proposed rule required that monitoring data be collected

during periods of SSM. Commenters requested that the EPA allow a

provision for ceasing to collect monitoring data at a particular

control device if operating that monitoring device during periods

of SSM would damage the monitoring device. The EPA revised the

final rule to allow the owner or operator to cease collecting

monitoring data if the owner or operator has illustrated that the

monitoring device would be damaged or destroyed if it were not

shut down during the SSM period. Such a provision must be

included in the Start-up, Shutdown, and Malfunction Plan. 

Getting such a provision in the Start-up, Shutdown, and

Malfunction Plan is accomplished by submitting a request, and

rationale defending the request, in the Precompliance Report or

in a supplement to the Precompliance Report.
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2.0 SUMMARY OF PUBLIC COMMENTS AND RESPONSES

A total of twelve letters commenting on the proposed

standards and the supplementary information document (SID) for

the proposed standards were received. A public hearing was not

requested and, therefore, none was held. A list of the

commenters, their affiliations, and the EPA docket number

assigned to their correspondence is given in Table 2-1.

For the purpose of orderly presentation, the comments have

been categorized under the following topics:

Applicability

Compliance and Relationship to Other Rules

Definitions

Process Vents Control Requirements

Extended Cookout as a Control Option

Process Vent Monitoring Requirements

Group Determination for Nonepoxide HAP Emissions

Emission Factor

Storage Vessel

Wastewater

Equipment Leak Provisions

Testing Requirements

Parametric Monitoring

General Recordkeeping and Reporting

Editorial Comments

Legal Considerations 

In the comment summaries and responses contained in the

following sections, when a change to specific rule language is

discussed, the new language is represented by underlining, while

the text that the commenter recommended removing or the EPA has

decided to remove is represented in strikeout font.
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2.1 APPLICABILITY

2.1.1 PMPUs Without Organic HAP

Comment: Three commenters (IV-D-04, IV-D-05, and IV-D-07)

stated that PMPUs that do not use or manufacture any organic HAP

should comply with 63.1420(b)(1) or (b)(2), not (b)(1) and

(b)(2). The equivalent of (b)(2) originated in the HON as a

settlement provision. According to the commenters, its intent is

to provide an alternative to (b)(1), so that if an owner or

operator (some years after the compliance date) cannot find the

original documentation that a process is exempt, this does not

result in civil or criminal penalties for noncompliance with a

recordkeeping requirement even though the process really does

qualify for the exemption. According to the commenters, this

approach also allows facilities to reduce the recordkeeping

burdens by choosing not to keep records perpetually, so long as

they accept the duty to demonstrate exemption on demand.

Response: The EPA agrees that §63.1420(b) should allow

owners or operators at PMPU’s without organic HAP to comply with

either §63.1420(b)(1) or §63.1420(b)(2), and the EPA has made the

suggested changes. 

Comment: One commenter (IV-D-05) supported the exclusion of

PMPUs without organic HAP from applicability to the rule. To

clarify when a facility may qualify as not manufacturing or using

an organic HAP, the commenter recommended adding a new sentence

after the first sentence in §63.1420(b), as follows:

"A facility does not use or manufacture organic HAP if (a) a

HAP is used for reasons other than making the product, such as,

but not limited to, occasional cleaning of parts, or in paint

that is applied to components of the facility, or (b) a HAP is

produced as a trace impurity."

Commenter (IV-D-09) suggested that the phrase "or contains

organic HAP as impurities only" be added for clarity so that
2-3

§63.1420(b) would read: "The owner or operator of a PMPU that is

part of an affected source, as defined in paragraph (a) of this

section, that does not use or manufacture any organic HAP, or

contains organic HAP as impurities only, shall comply with

paragraphs (b)(1) and (b)(2) of this section...." The commenter

stated that this change would also be consistent with

§63.1420(c)(8), which exempts “Vessels and equipment storing

and/or handling material that contains no organic HAP or organic

HAP as impurities only.” 

Response: The EPA does not feel that the new sentence that

the commenter requested adding to §63.1420(b) is necessary. The

EPA believes that the requirement to retain information to

document the basis for the determination that the PMPU does not

use any organic HAP, in §63.1420(b)(1), will verify to

enforcement personnel that even when a PMPU uses HAP in cleaning

supplies, or produces a product that contains a HAP as a trace

impurity, the PMPU still fulfills the category of "PMPUs without

organic HAP." Further, the EPA agrees with Commenter IV-D-09's

suggestion to clarify §63.1420(b) by addressing the fact that

HAP may be present as impurities only; however, the wording

suggested by the commenter is not consistent with the section. 

Therefore, the EPA revised §63.1420(b) in the final rule to read

as follows: 

"(b) PMPUs without organic HAP. The owner or operator of a

PMPU that is part of an affected source, as defined in

paragraph (a) of this section, but that does not use or

manufacture any organic HAP shall comply with the

requirements of either paragraph (b)(1) andor (b)(2) of this

section. Such a PMPU is not subject to any other provisions

of this subpart and the owner or operator is not required to

comply with the provisions of subpart A of this part. 

Products or raw material(s) containing organic HAP as

impurities only are not considered organic HAP for the

purposes of this paragraph."

2.1.2 Definition of Affected Source
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Comment: One commenter (IV-D-05) stated that §63.1420

(a)(2), (a)(3), and (a)(4)(i) refer to emission points and

equipment "associated with each group" of PMPUs in an affected

source. This implies there could be more than one group. 

Instead, the commenter suggested this section should read

"associated with the group" of PMPUs in an affected source. 

There is only one group, and only one affected source, at a site. 

Therefore, the commenter recommended changing the text in

§63.1420(a)(2) as follows:

"Emission points and equipment. The affected source also

includes the emission points and equipment specified in

paragraphs (a)(2)(i) through (a)(2)(iv)(vi) of this section that

are associated with the each group of polyether polyol

manufacturing process units (PMPU) making up an affected source,

as defined in §63.1423."

The commenter requested that similar changes also be made in

§63.1420(a)(3) and (a)(4)(i).

Response: The EPA agreed with the commenter, and has

replaced the term “each group” with the term “the group,”

throughout §63.1420(a). In addition, to clarify that the

equipment that was listed in §63.1420(a)(2) at proposal is part

of the affected source, but separate from the PMPU, the list

proposed under §63.1420(a)(2) has been moved to §63.1420(a)(4),

the other subparagraphs in §63.1420(a) have been re-lettered

accordingly, and, in the final rule, these paragraphs refer to

“the group of one or more PMPU and associated equipment, as

listed in paragraph (a)(4) of this section,” instead of just

referring to the “group of one or more PMPU,” as was done at

proposal.

As a point of clarification, the commenter is incorrect in

their assertion that there can only be one affected source at a

plant site. Under most circumstances, this would be the case. 

However, consider a situation where a new PMPU with potential HAP
2-5

emissions greater than 10/25 tons per year is added to a plant

site that already had an existing source consisting of a group of

PMPUs. In accordance with §63.1420(g), the newly added PMPU would

be a new affected source. Therefore, there would be two affected

sources at the plant site, a new affected source and an existing

affected source.

2.1.3 Processes Exempted from Affected Sources

Comment: One commenter (IV-D-05) requested that EPA delete

the words "separate entities and" in §63.1420(d)(2). According

to the commenter, they are not necessary, and they are

potentially inaccurate. The term "entity" is typically

interpreted as meaning a separate company, which the commenter

believes was not the EPA’s intent.

Response: The EPA agrees with this comment and has deleted

the words as suggested. In the final rule, §63.1420(d)(2) reads

"...(TSDF) requiring a permit under 40 CFR part 270 that are

separate entities and not part of a PMPU...."

Comment: One commenter (IV-D-05) stated that §63.1420(d)(3)

exempts reactions and processing that occur "after the

manufacture of polyether polyol products." The commenter agrees

that once the basic chemical reaction has occurred that produces

the polyol, further reaction to form derivatives should be

exempt. However, one possible interpretation of this section is

that a polyether polyol "product" does not exist until after some

of these additional steps have occurred. Therefore, for clarity,

the commenter recommended changing these provisions as follows:

"reactions or processing that occur after the manufacture of

polyether polyol products epoxide polymerization is complete and

after any catalyst removal step is complete."
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Response: At proposal, §63.1420(d)(3) exempted "reactions or

processing that occur after the manufacture of polyether polyol

products." The commenter's suggested language is preferable,

since it omits the use of the word "product." This eliminates

the possible interpretation that a polyether polyol “product”

does not exist until after some of the additional steps have

occurred. However, there may be more than one catalyst removal

step; therefore, the final rule reads "reactions or processing

that occur after the manufacture of polyether polyol products

epoxide polymerization is complete and after all catalyst removal

steps are complete.”

2.1.4 Necessity of Primary Product Redetermination

Comment: One commenter (IV-D-04) requested that EPA clarify

whether redetermination of the primary product is mandatory or

optional in §63.1420(e)(4)(i) of the proposed rule. The

commenter currently interprets this paragraph as allowing, but

not requiring, a redetermination of the primary product. 

Response: The EPA agreed that the portion of the primary

product provisions cited by the commenter needed clarification. 

In fact, the EPA conducted an overall review of the proposed

primary product provisions, and concluded that several structural

and clarifying changes were needed. In addition, the EPA noted

some potential situations that could occur that were not

addressed in the proposed provisions. The portions of the final

rule that address the commenter’s specific concern are discussed

below, followed by a general summary of other changes to the

primary product determination provisions.

With regard to the specific concern cited by the commenter,

specifies procedures for a required annual applicability

determination (beginning five years after the promulgation of the

final rule) for non-PMPU's that have produced a polyether polyol

product at any time in the preceding 5-year period or since the
2-7

date that the unit began production of any product, whichever is

shorter. The method for performing this annual applicability

determination requires the owner or operator to calculate the

percentage of total operating time each product was produced

during the applicable time period. If a polyether polyol product

was the product with the highest percentage of total operating

time over that period, then the flexible operation unit is

designated as a PMPU.

 If a process unit has not produced any polyether polyol in

the previous five-year period, but the owner or operator

anticipates that their non-PMPU will begin manufacturing a

polyether polyol product in the near future, the provisions in

paragraph 63.1420(e)(4) in the final rule apply. This provision

basically requires the owner or operator to redetermine the

primary product for the process unit based on their prediction on

the anticipated production for the five years (or one year, for

new process units) following the date that production of a

polyether polyol will be initiated. 

The proposed provisions required that the initial primary

product determination be based on a five-year prediction of

anticipated production by the owner or operator. The EPA was

made aware that, in some instances, the owner or operator may not

be able to make such a prediction. Clarifications and/or

revisions were made to the primary product provisions to address

this situation. First, in the initial determination, the time

frame for which production must be anticipated for new process

units was changed to one year. Also, provisions were added for

owners or operators that cannot determine the primary product

based on anticipated 5-year (or 1-year) production. First, the

process unit is not a PMPU if the owner or operator cannot

determine the primary product, but can determine that the primary

product is not polyether polyol. If the owner or operator cannot

determine a primary product, and cannot determine that polyether

polyol is not the primary product, then the process unit is
2-8

designated as a PMPU and subject to the existing source

provisions of subpart PPP if polyether polyols have been produced

in an existing process unit for 5 percent or greater of the time

since September 4, 1997. The EPA believes that if production is

so uncertain that an owner or operator cannot determine the

primary product based on future production, the fact that

polyether polyols have been produced in the unit since proposal

of the rule for even a small amount of time is sufficient basis

for having the process unit be subject to subpart PPP. For new

process units, if polyether polyols will be produced at any time

during the first year of production, then the unit is a PMPU and

subject to the new source provisions of subpart PPP.

In addition to the provisions discussed above that specify

how non-PMPUs are to determine if they become PMPUs and subject

to subpart PPP, the EPA has also clarified and expanded the

provisions that specify how the PMPU designation can be removed

from a process unit. The first case, which is retained from the

proposed rule, is where production of polyether polyols ceases

and the owner or operator does not anticipate the production of

polyether polyols in the future. Also, the EPA has added

provisions that specify procedures for a primary product reevaluation based on actual production. If an owner or operator

of a PMPU finds that another product has been produced for a

greater amount of time than polyether polyols over a specified

time period (previous five years or since beginning the

production of polyether polyols), then the PMPU designation would

possibly be removed. The stipulation is that production of the

“new” primary product must make the process unit subject to

another part 63 NESHAP. If the new primary product is not

subject to another part 63 NESHAP and polyether polyols continue

to be produced, the process unit continues to be classified as a

PMPU and continues to be subject to subpart PPP.

The EPA has also added provisions addressing the

determination of the primary product in situations where two or
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more products are produced simultaneously. Also, clarifications

were made in the reporting and recordkeeping requirements

associated with the primary product determination.

Comment: Two commenters (IV-D-04, IV-D-05) stated that

§63.1420(e)(4)(ii) of the proposed rule applies "if a process

unit meets the criteria of paragraph (e)(4)(i)...." However,

Commenter IV-D-04 maintained that it is literally impossible for

any individual process unit to meet all of the criteria of

paragraph (e)(4)(i), because that paragraph has two opposite

kinds of criteria. It has criteria for process units that are

subject to the rule, and criteria for process units that are not

subject to the rule. So, in order to meet "the criteria" of

paragraph (e)(4)(i), a process unit would have to be both subject

to the rule, and not subject to the rule. To clarify this

situation, the commenters recommended changing the text of

paragraph (e)(4)(ii) as follows:

"If a process unit meets the criteria of paragraph (e)(4)(i)

of this sectionis subject to this subpart,..."

Response: As mentioned in the response to the previous

comment, the EPA has largely re-written and re-structured

§63.1420(e), to resolve problems such as the one pointed out by

the commenters (IV-D-04 and IV-D-05). The paragraph referred to

by the commenters [§63.1420(e)(4)(ii)] no longer contains the

language that the commenters were concerned about, and conflicts

such as the one mentioned by the commenters should not occur in

the final version of §63.1420(e).

2.1.5 Primary Product Determination and Applicability

Comment: One commenter (IV-D-05) maintained that the

sentence in §63.1420(e) that reads "Paragraphs (e)(3) through

(e)(4) of this section describe whether or not a process unit is

subject to this subpart" is inaccurate. The commenter stated
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that the referenced paragraphs merely describe the relevance of

the primary product determination to whether or not a process

unit is subject to this subpart. Therefore, for clarity, the

commenter recommended changing this sentence, as follows:

"A process unit may be subject to the requirements of this

subpart if it meets the criteria of paragraphsParagraphs (e)(3)

through (e)(4) or (e)(5) of this section describe whether or not

a process unit is subject to this subpart."

Response: As discussed earlier, the EPA has re-structured

§63.1420(e), and the language that the commenter objected to no

longer exists in the final rule. The language in the final

version of §63.1420(e) is much more explicit about the roles of

the different sub-paragraphs under §63.1420(e) than the proposed

version was, and should cause no similar confusion.

2.1.6 Primary Product Determination for Non-Flexible

Operation Units

Comment: One commenter (IV-D-05) requested that a paragraph

be added between §§63.1420(e)(1) and (e)(2), telling how to

determine the primary product if (a) the unit is not a flexible

operation unit, and (b) the unit produces two or more products. 

According to the commenter, the HON and similar rules have such a

provision. There is simply no way to tell what the primary

product is if a non-flexible operation unit has two or more

"product" streams simultaneously. Therefore, the commenter

recommended making this provision consistent with the HON rule

(§63.100(d)(1) and (2)) by inserting the following new subsection

and renumbering the subsequent clauses accordingly:

"(e)(2) If a process unit is not designed and operated as a

flexible operation unit and the unit produces more than one

intended product, the product with the greatest annual design

capacity on a mass basis represents the primary product of the

process unit."
2-11

Response: The EPA agrees that §63.1420(e) needed to include

a provision for process units that are not flexible operation

units but that produce two or more products simultaneously. 

Under the newly re-structured §63.1420(e), §63.1420(e)(1)(ii)

provides provisions addressing such a situation. Although the

commenter’s recommended change was not incorporated exactly as

suggested, the EPA believes that the changes to §63.1420(e) will

alleviate the commenter’s concern.

2.1.7 Applicability for Flexible Operation Units

Comment: One commenter (IV-D-07) referred to the provisions

in §63.1420 and §63.1423 of the proposed rule which flexible

operation units must use to determine whether they are covered by

the rule. The commenter requested that EPA provide the option in

the final rule for flexible operation units that do not

technically qualify as PMPUs to be able to "opt in" to the rule

if it makes administrative sense to the owner/operator to do so. 

For example, the commenter might prefer to "opt in" to subpart

PPP rather than be subject to a future MACT standard such as the

Miscellaneous Organic NESHAP (MON), so as to have only one

standard to meet in the administrative unit. The commenter added

that the flexible operation unit concept is workable and should

be retained.

Response: The EPA appreciates the commenter’s desire to be

subject to only one MACT standard; however, the change requested

by the commenter (where a flexible operation unit that is not a

PMPU, could opt into the Polyether Polyols NESHAP because the

non-PMPU flexible operation unit is in the same “administrative

unit” as the facility's other PMPUs) is not being granted. While

the EPA recognizes that the owner/operator would benefit from

greater ease of compliance, it is the EPA’s position that an

affected source should be defined by the products that it makes,
2-12

and not solely by the products made near it. Defining the

affected source solely based on the owner or operator’s choice of

standards would allow a source that might otherwise be subject to

a more stringent rule to “opt in” to subpart PPP. However, in

the final rule, provisions have been added [e.g.,

§63.1420(e)(10)(iii)] that ensure that a source that is no longer

making a polyether polyol as its primary product will not be

subject to subpart PPP as well as to another MACT standard at the

same time.

2.1.8 Requirements for Flexible Operation Units when

Producing Non-polyether Polyols

Comment: One commenter (IV-D-07) expressed concern that the

proposed rule could be interpreted as requiring installation of

additional controls for periods when the flexible operation unit

is producing a product other than the primary product and

believes that clarification is needed to confirm that this is not

a valid interpretation. In order to clarify the compliance

concern, the commenter suggested that the following sentence be

added as a new §63.1420(e)(7)(iv):

"So long as the owner or operator of a flexible operating

unit is able to demonstrate compliance during the production of

the primary product, then no additional control device, recovery

device, and/or recapture device is required to be installed (to

otherwise demonstrate compliance) for periods when the flexible

operating unit is producing a product other than the primary

product."

The commenter stressed that similar wording was added in the

HON (§63.103(b)(6)).

Response: The EPA clearly did not consider the option that

flexible unit operations could be required to install additional

controls for periods when the flexible operation unit is

producing a product other than the primary product. The addition
2-13

suggested by the commenter has no effect other than to warrant

against this possibility. Therefore, the sentence was added as a

new paragraph under §63.1420(e)(5), as §63.1420(e)(5)(iii),

rather than at §63.1420(e)(7)(iv) as the commenter suggested, due

to the general restructuring of §63.1420(e). The language has

been edited slightly from that suggested by the commenter. The

new language in §63.1420(e)(5)(iii) reads:

(iii) So long as the owner or operator of a flexible

operation unit is able to demonstrate compliance with this

subpart during the production of polyether polyols, then no

additional combustion device, recovery device, and/or

recapture device is required to be installed (to otherwise

demonstrate compliance) for periods when the flexible

operation unit is producing a product other than a polyether

polyol. However, while a product other than polyether

polyol is being produced, the owner or operator shall

continue to operate any existing combustion, recovery,

and/or recapture devices that are required for compliance

during production of the primary product. If extended

cookout (ECO) is the control technique chosen for epoxide

emission reduction, then ECO or a control technique

providing an equivalent reduction in epoxide emissions

should continue to be used for epoxide emission reduction,

if the non-polyether polyol being produced uses epoxide

monomers. If ECO is used, the parameter monitored for ECO

shall be averaged for all product classes produced. The ECO

for non-polyether polyol production shall be performed so

that the averaged parameter is maintained when the ECO is

used as a control technique during the production of

nonpolyether polyols.

2.1.9 NonPMPUs that Produce Polyether Polyols

Comment: One commenter (IV-D-05) expressed concern that the

last sentence in §63.1420(e)(6) imposes a recordkeeping

requirement on all processes that are determined not to be PMPUs. 

The commenter suggested two changes to ease the burden on sources

that are not intended to be covered by the rule. First, this

sentence should apply only to processes that produce some

polyether polyol product. For example, a source should not have

to keep records proving that a dedicated chlorine plant,

magnesium plant, or methyl cellulose plant is not a PMPU. 
2-14

Second, there should be two options: keep records, or document,

on demand, that the process is not a PMPU. That way, if a

facility does not have the records available many years later,

but the process really is not a PMPU, there is no violation. The

commenter believed these changes would be consistent with EPA’s

intent. Therefore, the commenter recommended changing the text

as follows:

"For a process unit that produces some polyether polyol but

If the primary product of that process unit is determined to be

something other than a polyether polyol product, the owner or

operator shall retain information, data, and analysis used to

document the basis for the determination that the primary product

is not a polyether polyol product or must be able to document

that the process unit is not a PMPU."

Response: The suggestion that the owner or operator of a

process unit dedicated to the production of a product other than

a polyether polyol would have to maintain records is a

misinterpretation of proposed §63.1420(e)(6), since that

paragraph addressed flexible operation units, not dedicated

operation units. In the final rule, a flexible operation unit is

defined as a process unit that manufactures different chemical

products in addition to polyether polyols, by periodically

alternating raw materials fed to the process unit or operating

conditions at the process unit. 

The commenter's second request was that owners or operators

of flexible operation units with a primary product that is not a

polyether polyol have the option of keeping records documenting

the fact that the process unit is not a PMPU, or of providing

such documentation “on demand,” to the Administrator, if

requested to do so. The EPA agrees that this is a reasonable

request, and has incorporated this type of provision into the

restructured §63.1420(e), which appears in the final rule. The

proposed paragraph §63.1420(e)(6) no longer exists, and
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§63.1420(e)(8) in the final rule provides the “document on

demand” option that the commenter requested.

2.1.10 Changes or Additions to Plant Sites

Comment: One commenter (IV-D-07) stated that

§63.1420(g)(1)(i)(D) indicates that if a new PMPU is added to a

site where a polyether polyol is not currently produced as the

primary product of an affected source (and the plant site is a 

major source either before or after the addition), the unit will

be subject to new source MACT regardless of the emissions from

the new unit. The commenter claimed that this was an arbitrary

criterion for first time addition of a PMPU to an integrated

complex and it removes substantial pollution prevention incentive

to keep new units under the 10/25 criteria and makes no sense

from a policy standpoint. The commenter suggested that this

paragraph be deleted in the final rule.

Response: The EPA disagrees with the statement that the

proposed provisions related to the first-time addition of a PMPU

to a plant site are arbitrary. Rather, these provisions are

consistent with the Clean Air Act and the General Provisions of

part 63 (40 CFR part 63, subpart A). In the Clean Air Act, a new

source is defined as “a stationary source the construction or

reconstruction of which is commenced after the Administrator

first proposes regulations under this section establishing an

emission standard applicable to such source.” The definition in

the General Provisions mirrors the Clean Air Act definition,

except that it uses the term “affected source” rather than

“stationary source.” 

If, after September 4, 1997 (proposal date of subpart PPP),

a PMPU is constructed at a major source plant site where no PMPUs

previously existed, then the new PMPU cannot be considered to be

“an addition” to an “existing” affected source, since there was

no “existing affected source” at the facility. The criteria for
2-16

whether or not one or more newly added PMPUs constitute a “new

affected source” relies on whether or not the plant site is a

“major source” (before or after the addition of the PMPU). 

However, if the plant was not a major source (i.e., was an area

source) before the addition of the one or more PMPUs, and is

still not a major source after the addition of the PMPU(s), it

remains exempt from the requirements of this rule, as an area

source. 

These provisions have not changed since proposal, although

the intent of the requirements has been clarified in this final

rule. The EPA believes that these provisions are both reasonable

and consistent with the intent of the Clean Air Act and the

General Provisions to part 63.

Comment: One commenter (IV-D-07) maintained that the entire

affected source should not be subject to new source MACT if

reconstructed. The impact of the proposed wording in

§63.1420(g)(2)(i) is that if a PMPU in a location makes a

substantial investment to modernize such that reconstruction is

triggered, other PMPUs at the location would be required to

install new source MACT, even though they are not undergoing

changes. The commenter suggested that the HON approach be used

under subpart PPP to avoid this impact. The wording used in the

HON (§63.100(l)(2)) states that "If any change is made to a

chemical manufacturing process unit subject to this subpart, the

change shall be subject to the requirements of a new source in

subparts F, G, and H of this part...."

Response: The impact that the commenter objected to (i.e.,

that all PMPUs in the affected source become subject to the new

source MACT) is the intended impact of the provisions of

§63.1420(g)(2)(i). If activity at an existing affected source

constitutes reconstruction, the existing source becomes a new

source by definition. Reconstruction is triggered when the cost
2-17

of a modernization project exceeds 50 percent of the fixed

capital cost that would be required to construct a comparable new

affected source. In subpart PPP, the EPA defined the “affected

source” as all process units that produce polyether polyols as

their primary product at a plant site, along with all waste

management units, maintenance wastewater, heat exchange systems,

and equipment used to comply with subpart PPP that are associated

with the PMPUs. Therefore, the EPA expects that it would have to

be a substantial modernization for the cost to exceed the cost of

50 percent of the entire affected source.

To address the commenter’s example, assume that there are

four PMPUs at a plant site. By definition, the group of four

PMPUs, along with the associated equipment, make up an existing

affected source. If an investment was made to modernize one

PMPU, that investment would need to exceed the cost of

constructing four new PMPUs comparable to those at the site to

trigger reconstruction. The EPA believes that it is unlikely

that the modernization of one PMPU would ever cost more than 50

percent of the construction of four new comparable PMPUs. 

Therefore, all four PMPUs would remain an existing affected

source. If, however, the cost of that modernization did exceed

50 percent of the cost of four new PMPUs, the EPA believes that

it is reasonable, and in fact consistent with the intent of the

definition of reconstruction, for the entire affected source to

be subject to the new source requirements in subpart PPP.

Comment: One commenter (IV-D-05) maintained that if

“reconstruction” causes "the entire affected source" to become a

new affected source, then the rule should at least clarify that

"the entire affected source" is the capital base for deciding

whether a reconstruction has occurred. To clarify when a

modification is considered reconstruction such that the process

unit becomes subject to this subpart, the commenter recommended

changing the text in §63.1420(g)(2)(i) as follows:
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"(i) If any process change is made or emission

point is added to an existing affected source, the

entire affected source shall be a new affected source

and shall be subject to the requirements for a new

affected source in this subpart upon initial start-up

or by [insert date of promulgation], whichever is

later, if the process change or addition meets the

criteria specified in paragraphs (g)(2)(i)(A) through

(g)(2)(i)(B) of this section:

(A) It is a process change or addition that meets

the definition of reconstruction in §63.2 of subpart A.

For purposes of determining whether the fixed capital

cost of the new components exceeds 50 percent of the

fixed capital cost that would be required to construct

an entire affected source, the equivalent capital cost

shall be the entire potentially affected source; and

..." 

Response: The commenter's requested change to paragraph

63.1420(g)(2)(i) clarifies the EPA's intent at proposal, which

was to be consistent with the fact that the definition of

reconstruction is based on the entire potentially affected new

source. The EPA has changed added the sentence requested by the

commenter (with minor edits) to §63.1420(g)(2)(i)(A) in the final

rule.

2.1.11 Applicability of this subpart except during periods of

start-up, shutdown, malfunction, or non-operation

Comment: One commenter (IV-D-04) requested that EPA add the

words "to the extent practical" in §63.1420(h)(3) of the final

rule. These words were added in the HON as part of a litigation

settlement amendment. Their intended purpose is to clarify the

extent to which emissions must be minimized in certain unusual

situations where the standard’s "normal" requirements do not

apply. If the words are not added, there will be uncertainty as

to what degree of emission reduction must be achieved. 

Response: The EPA agrees with this comment, and the phrase

"to the extent practical" has been added to §63.1420(h)(4) in the
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final rule [which replaces proposed paragraph §63.1420(h)(3)]. 

The additional language is consistent with the HON

[§63.102(a)(4)] as well as with the proposed amendments to the

Polymers and Resins I and IV NESHAP [§63.480(j)(4) and

§63.1310(j)(4), respectively.]

2.1.12 Storage Tank Predominant Use

Comment: One commenter (IV-D-04) suggested that EPA limit

the applicability of §63.1420(f)(8) of the proposed rule, which

requires industry to redetermine storage vessel ownership if

something happens that could reasonably change the predominant

use of the storage vessel. The commenter stated that this

assumes that the original ownership was based on "predominant

use," rather than being based on "dedicated to a single process

unit" or some other basis. It also assumes that possible future

changes in predominant use were not already taken into account in

the original ownership determination. The commenter stated that

either of these assumptions could be false and cited two examples

to support the claim. The commenter requested that EPA revise

§63.1420(f)(8) as follows:

"(8) If a storage vessel has been assigned to a process

unit that is not a PMPU on the basis of predominant use under

(f)(3) of this section, and there is a change in the utilization

of the storage vessel that could reasonably be expected to change

the predominant use, the owner or operator shall redetermine to

which process unit the storage vessel belongs by reperforming the

procedures specified in paragraphs (f)(2) through (f)(7) of this

section, as appropriate."

Response: The EPA agrees with the commenter that the

proposed criteria for when a storage vessel ownership

redetermination is required [in §63.1420(f)(8)] should be more

specific. However, the EPA does not believe that the language

suggested by the commenter is the most appropriate solution. In

consideration of this issue, the EPA reexamined the circumstances

under which it is necessary to reevaluate storage vessel
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ownership. The EPA concluded that it is not necessary to require

a storage vessel ownership redetermination unless the storage

vessel has begun receiving material from (or sending material to)

a process unit that was not included in the initial

determination, or has ceased to receive material from (or send

material to) a process unit that was included in the initial

determination. Therefore, the proposed §63.1420(f)(8) has been

replaced with the following paragraph:

(8) If there is a change in the utilization of the storage

vessel that could reasonably be expected to change the

predominant use, begins receiving material from (or sending

material to) a process unit that was not included in the

initial determination, or ceases to receive material from

(or send material to) a process unit that was included in

the initial determination, the owner or operator shall

redetermine to which process unit the storage vessel belongs

by performing the procedures specified in paragraphs (f)(2)

through (f)(7) of this section, as appropriate reevaluate

the applicability of this subpart to that storage vessel. 

2.1.13 §63.1420(e)(5)(ii)

Comment: For clarity, one commenter (IV-D-05) recommended

changing paragraph 63.1420(e)(5)(ii) to read:

"Alternatively, each the owner or operator shall determine

the applicability of the provisions of this subpart (e.g., Group

status) to each emission point ...Based on these findings, the

owner or operator shall comply with the applicable requirements,

that apply at any time based on emission point characteristics at

that time, as appropriate, regardless of what product is being

produced...."

Response: The first two suggested revisions are ones the

EPA has agreed to in response to other comments, and will

certainly generalize to paragraph 63.1420(e)(5)(ii) as well. The

last revision that the commenter suggested is somewhat awkward,

and could possibly be misinterpreted. The wording "based on

emission point characteristics at that time" could be construed

as meaning that the applicability status could change depending
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on that day's emissions. Further, the first part of the

suggested revision, "requirements that apply at any time," is

unnecessary since "any time" is such a nebulous term, and since

the requirements have monthly compliance demonstration

requirements to prove that they are being met (at any time). 

Therefore, the first two suggested revisions were incorporated

into the final rule; however, the third suggested revision was

not made.

2.1.14 Section 63.1420(c)(1) and (c)(8) Appear to be

Duplicative

Comment: One commenter (IV-D-05) stated that paragraphs

(c)(1) and (c)(8) in §63.1420 appear to duplicate one another. 

If this is the case, the commenter recommended replacing

paragraph (c)(1) with (c)(8), as follows, and renumbering the

subsequent paragraphs (c)(9) through (12):

"(1) Vessels and equipment storing and/or handling material

that contains no organic HAP or organic HAP as impurities

onlyEquipment that does not contain organic HAP and is located at

a PMPU that is part of an affected source."

Response: The EPA agrees that there is confusing overlap

between paragraphs §63.1420(c)(1) and (c)(8). However, the EPA

does not believe that the change suggested by the commenter

accurately communicates the intent of the two paragraphs. 

Paragraph §63.1420(c)(8) of the final rule has been revised to

the following:

"(8) Vessels and equipment storing that store and/or handle

handling material that contains no organic HAP or organic HAP as

impurities only."

2.2 COMPLIANCE AND RELATIONSHIP TO OTHER RULES

2.2.1 Time Periods

Comment: Two commenters (IV-D-04, IV-D-05) requested that a

paragraph similar to §63.100(k)(9) in subpart F of the HON be
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added to §63.1422 as paragraph(k). Commenter IV-D-04 provided

the following wording: 

"All terms in this subpart that define a period of time for

completion of required tasks (e.g., daily, weekly, monthly,

quarterly, annual), unless specified otherwise in the section or

subsection that imposes the requirement, refer to the standard

calendar periods." Commenter IV-D-05 suggested adding: "...,

unless altered by mutual agreement between the owner or operator

and the Administrator in accordance with §63.1422(k)."

Commenter IV-D-04 maintained that this paragraph is

important for the following reasons: (1) it ends the questions

about whether a month means 30 rolling days, and what to do if a

month has more or less days than that; (2) it eliminates the need

for a large number of definitions; and (3) it avoids having

irreconcilable conflicts with the HON, which would arise if this

rule defined time periods differently than the HON. 

Response: The EPA agrees that a paragraph based on

§63.100(k)(9) in subpart F of the HON was needed in the Polyether

Polyols NESHAP. The EPA has added language to what is

§63.1422(l) in the final rule, mirroring the language found in

§63.100(k)(9) in subpart F of the HON. In addition, the EPA has

added the condition "..., unless altered by mutual agreement

between the owner or operator and the Administrator in accordance

with paragraph (l)(1) of this section," to the end of §63.1422(l)

in the final rule.

2.2.2 Changes to the General Provisions

Comment: One commenter (IV-D-04) suggested that additional

notice and comment rulemaking would be necessary if EPA makes

future changes in the General Provisions that apply to this rule. 

The commenter referred to the following statement in the proposal

preamble (62 FR 46812, col. 2): "If this subpart is promulgated

subsequent to the promulgation of the amendments to the General
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Provisions, the amended General Provisions will be incorporated

into this subpart." The commenter stated that, according to the

CAA’s administrative procedures requirements, any amendment of

the polyether polyols rule (such as changing General Provisions

that are incorporated into the rule by reference) would require

rulemaking.

Response: It is important that owners and operators realize

that provisions in subpart PPP that cross-reference the HON, the

General Provisions, or any other regulation, refer to the most

recent, promulgated versions of those rules. When such rules are

amended, the EPA will provide an opportunity for comment on the

effect that such changes will have on standards that crossreference these rules. The EPA believes that this practice meets

the requirements of the Clean Air Act.

2.2.3 Cross-references with Other Subparts

Comment: One commenter (IV-D-04) requested that EPA address

the overlap between the proposed rule and other MACT standards

for wastewater and/or heat exchange systems. In many instances,

the waste management units and heat exchangers that serve PMPUs

may already be subject to another MACT standard (generally the

HON) by the compliance date for this rule. There should be no

need to comply with each rule separately (duplicating the

reporting and recordkeeping requirements) when the substantive

requirements are essentially the same. Therefore, the commenter

suggested specific regulatory language that would address overlap

between subpart PPP and other MACT standards for wastewater

and/or heat exchange systems.

Response: The EPA agrees that it is appropriate to add a

paragraph at §63.1422(k) to address instances in which

requirements from other regulations overlap for the same heat

exchange system(s) or waste management unit(s) that are subject
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to subpart PPP. The language in §63.1422(k) in the final rule

states that owners and operators of affected sources that share

heat exchange systems with sources that are subject to subpart F

of part 63 or any other subpart of part 63 that references the

heat exchange system requirements in §63.104 in subpart F (e.g.,

subpart U) will be considered to be in compliance with subpart

PPP for heat exchange systems, if the shared heat exchange

systems are in compliance with the heat exchange system

requirements in that other subpart. Similarly, owners and

operators of affected sources that share waste management units

with sources that are subject to subpart G of part 63 or any

other subpart of part 63 that references the waste management

unit requirements in §63.132 through §63.147 of subpart G will be

considered to be in compliance with subpart PPP for the shared

waste management unit, if the shared waste management unit is in

compliance with the waste management unit requirements in that

other subpart. This change was made to ensure that owners and

operators are not subject to multiple sets of monitoring,

recordkeeping, or reporting requirements for the same equipment

due to the type of regulatory overlap that the commenter

described.

Comment: One commenter (IV-D-07) referred to §63.1422(j) of

the proposed rule, which discusses overlap with other regulatory

requirements, including RCRA. The commenter requested that the

provision be explicitly extended to "hazardous waste tanks"

regulated under 264 Subpart CC and 265 Subpart CC. The subject

hazardous waste tank emission controls include options other than

combustion and recovery devices; for example, pressure tanks and

certain types of pressure relief devices for low-vapor pressure

tanks are allowed. The commenter asserted that duplicative

monitoring, recordkeeping and reporting requirements should not

be imposed for these systems.
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Response: Section 63.1422(j) addresses overlap with other

regulations for monitoring, recordkeeping or reporting with

respect to combustion devices, recovery devices, or recapture

devices. The subjects of the monitoring, recordkeeping, and

reporting requirements in this paragraph are the combustion,

recovery or recapture devices, and not the source of the emission

control. Therefore, a specific provision for the hazardous waste

tanks regulated under 40 CFR part 264 subpart AA or CC and 40 CFR

part 265 subpart AA or CC is not appropriate. Further, the

requirements in 40 CFR part 264 subpart AA or CC and 40 CFR part

265 subpart AA or CC are already specifically cited in

§63.1422(j). 

2.2.4 Interfacing with Title V Operating Permit 

Comment: One commenter (IV-D-07) expressed concern that the

interface between this proposed rule and the Title V Operating

Permits program is not well defined and will result in

inadvertent compliance issues. For example, in a number of

sections of the proposal, reference is made to the need to

incorporate certain items into the operating permit or permit

application. Then in §63.1439(e)(8), the information to be

included in the application is limited to the information listed

in §63.1439(e)(4). The commenter suggested that EPA conduct a

search of the final rule to identify all interfaces with

Operating Permits and include an inclusive listing in the final

rule.

Response: It is not the EPA’s intent to incorporate all of

the Title V Operating Permit requirements into subpart PPP. The

owner or operator will always need to consult Title V in order to

determine all of the Operating Permit requirements that pertain

to a particular affected source, because Title V requirements are

site specific. Subpart PPP simply allows some information to be

submitted in either the Operating Permit application or the
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Notification of Compliance Status, and allows the owner or

operator to choose between submitting special requests (e.g., for

permission to use alternative monitoring parameters or controls)

in the Precompliance Report or in the Operating Permit

application. Information that is submitted in the Operating

Permit application will, once approved, become part of the

affected source’s Title V Operating Permit. Therefore, the EPA

has not included an “inclusive listing” in the final rule of all

interfaces with Operating Permits or operating permit

applications, particularly because the requirements in subpart

PPP related to Operating Permits or Operating Permit applications

are provided as alternatives to submitting information in other

reports. However, the EPA has made every effort to clarify this

distinction in the final rule.

2.2.5 Complexity of the Proposed Rule

Comment: Two commenters (IV-D-02, IV-D-03) expressed

concern regarding the complexity of the proposed rule and stated

that it would be costly for polyether polyol manufacturers to

interpret and comply with the rule, and for permitting

authorities to administer it. Commenter IV-D-03 stated that the

rule was unnecessarily complex due to frequent references to the

HON and the Polymer and Resins I and IV NESHAP. The commenter

recommended that the cited references to the HON and to the

Polymer and Resins NESHAP be replaced by the appropriate

regulatory language in the Polyether Polyols final rule. 

Response: The EPA realizes that the Polyether Polyols

Production NESHAP is relatively complex. The development of this

rule began with a preliminary maximum achievable control

technology (PMACT) partnership between the EPA and industry

representatives. During the roundtable PMACT discussions,

industry representatives requested unique emission limits for

three of the emission sources: epoxide emissions from
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polymerization; non-epoxide emissions from polymerization; and

non-epoxide emissions from catalyst extraction. This NESHAP

introduces extended cookout (ECO) as a new control option for

process vents. The explanation of how to measure and monitor the

effectiveness of this new control option contributes further to

the complexity of this rule. The EPA has attempted to keep the

rule brief by cross-referencing sections of the HON or subpart U

that apply to this rule. However, the EPA realizes that making

the rule shorter through cross-referencing other subparts of part

63 makes the rule more complicated. The EPA believes that crossreferencing other part 63 subparts is necessary in subpart PPP to

ensure that the source is subject to consistent requirements

across all the rules that cite other part 63 subparts.

2.3 DEFINITIONS

2.3.1 Annual Average Concentration

Comment: One commenter (IV-D-05) stated that the definition

of "annual average concentration" should not reference subpart G

if the chemical lists (Table 8 and/or Table 9 compounds) differ

in this rule. To clarify, the commenter recommended revising the

text, as follows:

"Annual average concentration, as used in conjunction with

the wastewater provisions, means the flow-weighted annual average

concentration and is determined by the procedures in §63.144(b)

of subpart G, except as provided in §63.1433(a)(2)."

Response: The addition requested by the commenter cites

§63.1433(a)(2), which in turn lists all the exceptions in

applicability to §63.132 through §63.149. The EPA agrees that

this revision clarifies the meaning of this definition, and has

added the phrase that the commenter suggested to this definition

in the final rule.

2.3.2 Batch Cycle
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Comment: One commenter (IV-D-05) claimed that the term

"batch cycle" does not match industry usage. To avoid confusion,

the commenter recommended changing the defined term to "batch

unit operation cycle."

Response: The definition of the term “batch cycle” clearly

states that the batch cycle means the steps that occur in a batch

unit operation. The rule then defines a batch unit operation. 

The EPA does not think that the phrase "batch cycle" differs

significantly from "batch unit operation cycle," and so has

decided not to revise the phrase.

2.3.3 Cross-referencing of Definitions from Other Rules

Comment: One commenter (IV-D-04) stated that the EPA should

not just refer to the HON or the Group I Polymers and Resins rule

for definitions that need different chemical lists, equations, or

calculations in this rule. The commenter requested that

additional clarifications be made in this regard in the following

areas:

(1) The definition of "in organic hazardous air pollutant

service" is borrowed from the HON, subpart H, which is

appropriate. However, EPA should clarify that the PEPO

definition of organic HAP applies.

(2) The definitions of "process wastewater" and "process

wastewater stream" are borrowed from the HON, subpart G, which is

appropriate. However, these defined terms ultimately depend on

whether something is "wastewater." Since the HON and this rule

each have a different definition of "wastewater," EPA should

clarify which one applies. 

(3) The definition of "total resource effectiveness (TRE)

index value" is borrowed from the HON. However, the TRE

definition relies on a TRE equation, and the equation was written

to derive an appropriate cost-effectiveness cutoff for control of

individual process vents. In contrast, this rule requires
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determination of the TRE index value for combinations of process

vents. Ideally, EPA should allow an option to conduct TRE

determinations on each individual process vent. However, if the

concept of combinations of process vents is retained, EPA should

revise the TRE equation (and hence, the definition). 

(4) The definitions of "combination of process vents that

are Group 1" and "Combination of process vents that are Group 2"

require use of §63.115 of the HON for TRE calculations, and

section 63.499(b) of subpart U for annual average flow

calculations. Both the HON and subpart U were written for

individual process vents, not for combinations of process vents. 

It seems unlikely that the same methods of calculation would work

appropriately in both contexts. Another commenter (IV-D-05)

expressed the same concern.

(5) The definition of "maintenance wastewater" relies on

subpart F of the HON, with some exceptions. The exceptions

apparently do not include chemical lists. The commenter believed

that the polyether polyols chemical lists would apply instead of

the HON chemical lists and requested that the definition of

Maintenance wastewater in the final rule be clarified

accordingly.

(6) The definition of "maximum true vapor pressure" relies

on subpart G of the HON, with some exceptions. The exceptions do

not include chemical lists. The commenter asked if that was

intentional and requested that the definition in the final rule

be revised to clarify that the polyether polyols chemical lists

apply.

(7) The definition of "residual" in the proposed rule is

confusing. It says that, instead of using the HON terminology

"Table 9 compounds," it uses the phrase "organic HAP listed in

Table 9 of subpart G." The commenter questioned this and stated

that if EPA really does intend to keep referring to the HON Table

9 but with different words than the HON uses, then EPA should

explain what the change is intended to accomplish. Contrarily,
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if EPA intended to refer to a polyether polyols table, then the

definition should be revised accordingly.

Response: (1) and (2): The EPA agrees that clarification is

needed. In the case of clarifying the definition of "in organic

hazardous air pollutant service", "process wastewater," and

"process wastewater stream," the EPA believes that it would be

clearer and simpler to copy the definitions from the HON into

subpart PPP. Therefore, the final rule contains definitions for

these three terms.

(3): As discussed in section 2.4.4 of this document, the EPA

has revised the rule such that the TRE equation is not applied to

aggregated streams. Therefore, the TRE equation applies only to

individual process vent streams (as in the HON), and the final

rule continues to reference the HON definition for "Total

resource effectiveness (TRE) index value".

(4): The concerns raised by these commenters regarding the

combination of process vents for the group determination is

addressed in section 2.4.4 of this document. To summarize, the

EPA agreed with the commenters regarding the group determination

for process vents from continuous unit operations that are

associated with the use of a nonepoxide organic HAP to make or

modify the product, and the final rule requires that these group

determinations be conducted on an individual vent basis. 

However, the final rule continues to require that the group

status of process vents from batch unit operations be determined

for the combination of process vents associated with the use of a

nonepoxide organic HAP to make or modify the product.

The change noted above necessitated a change in the proposed

definitions of “combination of process vents that are Group 1"

and “combination of process vents that are Group 2.” These

proposed definitions, which addressed both process vents from

continuous unit operations and process vents from batch unit

operations, were no longer appropriate for the final rule. 
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Therefore, the EPA defined separate terms for Group 1 and Group 2

process vents from continuous and batch unit operations.

The new terms used for process vents from batch unit

operations, which are provided below (as they appear in the final

rule), are “Group 1 combination of batch process vents” and

“Group 2 combination of batch process vents.”

Group 1 combination of batch process vents means a

collection of process vents in a PMPU from batch unit

operations that are associated with the use of a

nonepoxide organic HAP to make or modify the product

that meet all of the following conditions:

(1) Has annual nonepoxide organic HAP emissions,

determined in accordance with §63.1428(b), of 11,800

kg/yr or greater, and

(2) Has a cutoff flow rate, determined in

accordance with §63.1428(e), that is greater than or

equal to the annual average flow rate, determined in

accordance with §63.1428(d).

Group 2 combination of batch process vents means a

collection of process vents in a PMPU from batch unit

operations that are associated with the use of a

nonepoxide organic HAP to make or modify the product

that is not classified as a Group 1 combination of

batch process vents.

In the proposed rule, the relationship of the batch vent portion

of the definition of the “Combination of process vents that are

Group 1" to the provisions in §63.1428(f) was confusing. The

11,800 kg/yr annual nonepoxide organic HAP emissions cutoff was

not included in the definition, and the comparison of the cutoff

flow rate to the annual average flow rate was included in both

places. In order to clarify this situation, the definition of

“Group 1 combination of batch process vents” shown above includes

all criteria. This change in the final rule made §63.1428(f)

redundant with this definition. Therefore, the proposed

provisions in §63.1428(f) have been removed, and, in the final

rule, paragraph §63.1428(f) is reserved.

For process vents from continuous unit operations that are

associated with the use of a nonepoxide organic HAP to make or
2-32

modify the product, the terms in the final rule are “Group 1

continuous process vent” and “Group 2 continuous process vent.” 

In addition to changing the basis for this group determination to

an individual vent basis, the final rule also incorporates other

criteria not included in the proposed definition. The HON

definition of a Group 1 process vent includes three criteria:

flow rate, organic HAP concentration, and TRE index value. The

EPA intended for the proposed definition to mirror the HON

definition, but failed to include the flow rate and organic HAP

concentration criteria. Therefore, the final rule defines a

Group 1 continuous process vent as follows.

Group 1 continuous process vent means a process

vent from a continuous unit operation that is

associated with the use of a nonepoxide organic HAP to

make or modify the product that meets all of the

following conditions:

(1) Has a flow rate greater than or equal to 0.005

standard cubic meter per minute,

(2) Has a total organic HAP concentration greater

than or equal to 50 parts per million by volume, and 

(3) Has a total resource effectiveness value,

calculated in accordance with §63.1428(h)(1), less than

or equal to 1.0.

(5) and (6): The HON definitions of "maintenance

wastewater" and “maximum true vapor pressure” do not include

references to chemical lists, so the EPA does not understand why

there would be confusion regarding which chemical lists to use. 

However, the EPA has made a small edit to the definition of

“maintenance wastewater,” to clarify that the generation of

wastewater from the routine rinsing or washing of equipment in

batch operation between batches is not considered to be

“maintenance wastewater,” for the purposes of subpart PPP.

(7): The phrase "organic HAP listed in Table 9 of subpart

G" means the same thing as the HON's language "Table 9

compounds." The EPA made this distinction so that the language

in the Polyether Polyol's phrase would be consistent with the

language in the rest of the rule. The reason that the EPA is
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referring to Table 9 in subpart G is that Table 9 in subpart G

plays an instrumental part in the wastewater provisions in the

HON, which subpart PPP cross-references. 

2.3.4 Epoxide

Comment: One commenter (IV-D-04) maintained that the

definition of "epoxide" is needlessly broad and complex. The

commenter declared there are only two epoxides, for purposes of

this rule, and each has a name. The commenter recommended the

following revised definition: "Epoxide means ethylene oxide

and/or propylene oxide."

Another commenter (IV-D-05) also recommended shortening the

definition of "epoxide," similarly as follows:

"Epoxide means ethylene oxide and propylene oxide for

purposes of this subpart."

Response: The EPA has reviewed the current definition of

epoxide and the revisions suggested by the commenters. The EPA

does not agree that the definition of epoxide would benefit from

a revision. Due to the fact that other epoxides are used to make

polyether polyols, the definition of “epoxide” cannot be limited

to EO and PO. 

2.3.5 Extended Cookout

Comment: One commenter (IV-D-05) claimed that to conform

with industry usage, the definition of "extended cookout" should

be revised as follows:

Extended Cookout means a control technique that

reduces the amount of unreacted EO and/or PO (epoxides)

in the reactor. This is accomplished by allowing the

product to react for a longer time period, thereby

having less unreacted epoxides and reducing epoxides

emissions that may have otherwise been emitted

occurred.
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Response: The EPA appreciates the comment, and has modified

the definition of “extended cookout” in the final rule,

accordingly.

2.3.6 Impurity

Comment: Two commenters (IV-D-05, IV-D-07) claimed that

since the provisions for process vents apply to all process vents

in the process, the definition of "impurity" should be changed to

reflect that low epoxide levels which remain in the product are

indeed impurities. Commenter (IV-D-05) stated that the existing

HON definition is inadequate in this regard and the incorporation

of the subpart F definition should be deleted in this section. 

Both commenters suggested that the following definition be pulled

into subpart PPP from the HON, with the following revisions: 

 "Impurity means a substance that is produced coincidentally

with the primary product, or is present in a raw material, or is

a residual raw material that remains with the product after

production. An impurity does not serve a useful purpose in the 

use of the primary product and is not isolated." Commenter (IVD-07) noted that this revised definition is consistent with the

concept of extended cookout in §63.1427 and informal guidance

provided to sources subject to the HON.

Response: There is a fundamental difference between an

impurity and unreacted HAP-reactant. The unreacted HAP-reactant

is a primary source of emissions from polyether polyols

production. The EPA does not consider it appropriate to classify

unreacted reactants as impurities. Therefore, the final rule

continues to cross-reference the HON definition in §63.101.

2.3.7 Make or Modify the Product

Comment: One commenter (IV-D-05) claimed that, for clarity,

the definition of the phrase “make or modify the product” should

be revised as follows:
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"Make or modify the product means to produce the polyether

polyol by polymerization of epoxides or other cyclic ethers with

compounds having one or more reactive hydrogens, and to add any

preservatives, /antioxidants or diluents in order to maintain the

quality of the finished products before shipping. Making and

modifying the product for this rule does not include grafting,

polymerizing the polyol, or modifying reacting it with compounds

components other than EO or PO.

Response: The EPA appreciates the comment and has made the

revisions requested. However, the revised definition lists

additives parenthetically. The definition in the final rule reads

as follows: 

"Make or modify the product means to produce the polyether

polyol by polymerization of with epoxides or other cyclic

ethers with compounds having one or more reactive hydrogens,

and to add any preservatives/antioxidants incorporate

additives (e.g., preservatives, antioxidants or diluents)

in order to maintain the quality of the finished products

before shipping. Making and modifying the product for this

rule regulation does not include grafting, polymerizing the

polyol, or modifying reacting it with compounds other than

EO or PO.”

2.3.8 Non-epoxide HAP

Comment: One commenter (IV-D-05) stated that the phrase

"non-epoxide HAP," which appeared in the May 1997 draft rule that

was distributed for review, has been deleted from the definitions

section of subpart PPP (§63.1423). The May 1997 draft of the

rule based the Group 1/Group 2 determination solely on nonepoxide HAP emissions. According to the commenter, omitting the

term seems to include the epoxide emissions in the Group 1/Group

2 evaluation, which is a significant change. Section 63.1428,

which defines the Group 1/Group 2 evaluation, does not use the

epoxide emissions to determine the classification of the vent.
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Response: Section 63.1428 is entitled "Process vent

requirements for group determination of PMPUs using a nonepoxide

organic HAP to make or modify the product." The EPA did not

intend to create any confusion over the fact that the group

determination described in §63.1428(f) was based on nonepoxide

organic HAP emissions. The commenters are mistaken about the

phrase "non-epoxide HAP" appearing in the definition section of

the May 1997 version of the proposed rule. In the May 1997

version of the proposed rule the term "nonepoxide organic HAP"

was used throughout the rule, but never defined. The EPA does

not find it necessary to define this term since "epoxide" is

defined and "organic HAP" is defined. Furthermore, as described

earlier in this document, §63.1428(f) has been reserved in the

final rule, and the definitions of “Group 1 combination of batch

process vents” and “Group 2 combination of batch process vents”

(in §63.1423) now contain all of the criteria for the group

determination, including the fact that only nonepoxide organic

HAP are used in the group determination.

2.3.9 Organic HAP

Comment: Three commenters (IV-D-04, IV-D-05, IV-D-07)

expressed serious concern about the clause "or has been or will

be reported under any Federal or State program, such as EPCRA

section 311, 312, or 313 or Title V" in the definition of

"organic hazardous air pollutant" and requested that it be

deleted from the definition. One commenter (IV-D-04) posed

several questions regarding future reports of chemicals: (1) how

can they know what chemicals will be reported in the future; (2)

how far into the future must they predict; and (3) if they make a

mistake in future predictions, does that mean they retroactively

have 25 years of violations for not considering that chemical an

organic HAP? 

The commenter added that they could probably tell what

chemicals have been reported under the specific reporting laws
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mentioned. However, they could not figure out everything that

has been reported under the vast number of other laws that might

be included in this definition. The commenter concluded that

they would probably have some difficulty excluding any law and

gave examples, which included OSHA, TSCA, and State requirements.

In addition, commenter IV-D-07 requested that the definition

be restricted such that glycol ethers that have low volatility

will not be included in the definition of Organic Hazardous Air

Pollutant. The commenter produces a number of products and

intermediates which technically meet the wide CAAA definition of

"glycol ethers." The commenter suggested that the limited

listing of glycol ethers used in Table 4 or 9 of the HON would be

an appropriate sub-list for inclusion as HAPs under subpart PPP. 

Commenter IV-D-05 suggested the following language:

"Organic hazardous air pollutant(s) (organic HAP) means one

or more of the chemicals listed in Table 4 of this subpart or any

other chemical which:

(1) Is is knowingly introduced into the manufacturing

process other than as an impurity, or has been or will be

reported under any Federal or State program, such as EPCRA

section 311, 312, or 313 or Title V; and

(2) Is is listed in Table 2 of subpart F of this part."

Response: The EPA has amended the definition of “organic

hazardous air pollutant.” The definition that appears in the

final rule states that only chemicals listed in Table 4 of

subpart PPP, or chemicals listed in Table 2 of subpart F, that

are "knowingly produced or introduced" into the manufacturing

process constitute organic HAP for the purposes of subpart PPP. 

However, with regard to the comment that requested that low

volatility glycol ethers be exempted from the definition of

organic HAP (or that a limited listing of glycol ethers, such as

that used in table 4 and table 9 of subpart G, be used), table 4

and table 9 in subpart G both apply to the wastewater provisions
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in subpart G, which subpart PPP directly references. Therefore,

the EPA has decided that, with regard to wastewater, the “limited

listing” that the commenter mentions (in tables 4 and 9 of

subpart G) is applicable, while a limited listing of glycol

ethers for the other provisions in this subpart would be

inappropriate for subpart PPP.

2.3.10 Override Definitions

Comment: One commenter (IV-D-04) expressed concern about

paragraph (c) in §63.1423 of the Definitions section. This

paragraph addresses what to do if a referenced subpart of the HON

uses a term that is defined in the HON, in the proposed rule, or

both. The commenter believed that the introductory sentences of

§63.1423(b) addressed this and thus there is no need for proposed

§63.1423(c). Also, paragraph (c) leaves a number of other

scenarios unexplained. The following are two of four examples

cited by the commenter where doubt is created by the use of

paragraph (c): the HON uses a term that is defined in the General

Provisions, and (1) the term is not otherwise defined in the HON

or in the proposed rule, and neither the HON nor the proposed

rule expressly borrows the General Provisions definition; or (2)

the HON does not expressly borrow that definition from the

General Provisions, but the proposed rule does. The commenter

requested that EPA eliminate the doubt and confusion by deleting

paragraph (c) in §63.1423.

Response: The EPA agrees with the commenter, and has removed

§63.1423(c) from the final rule. The EPA decided that

§63.1423(b) was sufficiently clear regarding which definition

should be used with regard to the subpart PPP requirements.

2.3.11 PMPU

Comment: One commenter (IV-D-05) stated that the definition

of polyether polyol manufacturing processes (PMPU) uses the term
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"polyether polyol product," which is not defined. For clarity,

the commenter recommended changing the text to read:

"... means a collection of equipment assembled and connected

by process pipes or ducts, used to process raw materials and to

systems that are associated with the manufacture of a polyether

polyol product as its primary product."

Response: The definition of a PMPU in the proposed rule

read: "polyether polyol manufacturing process unit (PMPU) means

a collection of equipment assembled and connected by process

pipes or ducts, used to process raw materials and to manufacture

a polyether polyol product as its primary product." The

commenter correctly pointed out that the term "polyether polyol

product" was not defined. Therefore, the definition of

“polyether polyol manufacturing process unit" (PMPU) has been

modified by deleting the word "product" from the end of the

phrase "polyether polyol product”, instead of by using the

commenter's suggested language. The language suggested by the

commenter was not used because the word "system" is not defined

in the rule. 

2.3.12 Polyether Polyol

Comment: One commenter (IV-D-04) requested that EPA revise

the definition of "polyether polyol" to clarify that the

production of typical alkanolamines is not regulated under

subpart PPP. The commenter stated that the proposed definition

was worded broadly enough that it might be misinterpreted to

include alkanolamines. One alkanolamine (diethanolamine) is a

HAP; however, its production is regulated under the HON. The

commenter presented reasons why it does not believe that the EPA

intended to regulate alkanolamines under subpart PPP. However,

in the case where a manufacturer further reacts an alkanolamine

until it possesses repeating ether units, the end result is a

polyether polyol derivative of an amine. The commenter believed
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that, due to the batch nature of these processes and the chemical

structure of the derivative, these products should be considered

polyether polyols. However, they are a small exception and are

not typical of alkanolamines. Typical alkanolamines lack

repeating ether units, which are the hallmark of polyether

polyols. Therefore, the commenter urged EPA to add the following

sentence to the end of the definition of "polyether polyol" to

clarify that the production of typical alkanolamines is not

regulated under this rule:

"Polyether polyols do not include alkanolamines, in which

nitrogen is intentionally attached directly to the carbon of an

alkyl alcohol, unless the alkanolamine is further reacted to form

a molecule with more than three repeating ether units."

Response: The EPA agrees that the proposed definition of

"polyether polyol" needed some clarification. In the final rule,

"polyethers" are described parenthetically (in the definition of

“polyether polyol” as “compounds with two or more ether bonds".

The EPA believes that explaining what is meant by the term

"polyether" eliminates the possibility of owners or operators

interpreting alkanolamines as being part of the polyether polyol

source category. Therefore, the EPA did not add the sentence

suggested by the commenter to the final rule, but did revise the

final rule in a manner that should resolve the commenter’s

concern.

Comment: One commenter (IV-D-07) owns and operates a hydroxy

ethyl cellulose manufacturing facility. Hydroxy ethyl cellulose

is formed through the reaction of ethylene oxide with multiple

reactive hydrogen sites (actually hydroxyl sites) on cellulose

polymer molecules. According to the commenter, some standard

references classify hydroxy ethyl as a "polyether ether." 

Previous indications were that this type of manufacturing would

not be covered under this rule. For purposes of applicability,
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the commenter requested that EPA clarify whether hydroxy ethyl

cellulose manufacturing is included or excluded from the

definition of a polyether polyol.

Response: The EPA did not intend to make hydroxy ethyl

cellulose manufacturing facilities subject to the polyether

polyols rule, due to the cellulose component of the product. 

Therefore, to rule out the likelihood that others might consider

the production of hydroxy ethyls to be subject to subpart PPP,

the EPA has revised the definition of "polyether polyol" in the

final rule, clarifying that the production of hydroxy ethyls is

not subject to subpart PPP. The revised definition of "polyether

polyol in the final rule reads:

Polyether polyol means a compound formed through the

polymerization of ethylene oxide (EO) or propylene oxide

(PO) or other cyclic ethers with compounds having one or

more reactive hydrogens (i.e., a hydrogen atom bonded to

nitrogen, oxygen, phosphorus, sulfur, etc.) to form

polyethers (i.e., compounds with two or more ether bonds). 

This definition of "polyether polyol" excludes hydroxy ethyl

cellulose and materials regulated under the HON, such as

glycols and glycol ethers.

2.3.13 Pressure Decay Curve

Comment: One commenter (IV-D-05) asserted that the term

"pressure decay curve" is used in the rule without definition. 

According to the commenter, this is not a common technical term. 

Therefore, the commenter suggested adding a definition, as

follows:

"Pressure decay curve is the graph of the reactor pressure

versus time from the point when epoxide feed is stopped until the

reactor pressure is constant, indicating that most of the epoxide

has reacted out of the vapor and liquid phases. This curve must

be determined with no leaks or vents from the reactor. The

pressure decay curves for products that may have different

starting and finishing pressures may be compared by graphically
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determining the time when the pressure has fallen to half the

total pressure drop:

Phalf=(Pinital-Pfinal)/2 Equation x"

Response: The commenter was correct that the term “pressure

decay curve” was not defined in the definition section of the

rule. The EPA agrees with the definition presented by the

commenter, except for the last sentence. The last sentence,

which gives a reference point for comparison with other pressure

decay curves, is not germane to the definition of a pressure

decay curve for this rule. Therefore, the last sentence was not

included in the definition in the final rule. However, the last

sentence is important in determining a point of comparison

between two different pressure decay curves, and this concept was

incorporated under §63.1427(h) in the final rule.

2.3.14 Process

Comment: One commenter (IV-D-05) recommended deleting the

definition of "process" for two reasons. First, the word

"process" by itself does not appear to be a significant

regulatory term in this proposed rule. Second, the definition

could cause confusion. For example, the definition says a

"process" makes a polyether polyol. Yet, companies have a

"process" to make HON products, or to make epoxy products, etc. 

Similarly, the definition says a "process" may consist of one or

more unit operations. In contrast, a "process unit" (such as a

HON "chemical manufacturing process unit" or a PMPU for this

rule) consists of two or more unit operations. If a "process" is

not coextensive with a "process unit," what is it? Moreover, the

definition says a "process" includes "all or a combination of”

various processing steps, "or other activity, operation,

manufacture, or treatment" which are used to produce a polyether

polyol. Apparently, then, there could be multiple "processes" in

a "process unit." As a result of this, there is no way to tell
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what a "process" is or how to tell where one process ends and

another begins. Therefore, for clarity, the commenter

recommended deleting the definition of "process" because it is

adequate to use this term as part of other defined terms.

Response: The EPA agrees with the commenter that the word

"process" by itself is not a significant regulatory term. 

Further the EPA agrees that the definition of "process" in the

proposed rule is confusing. For these two reasons the EPA

deleted the definition of "process" from the final rule.

2.3.15 Process Condenser

Comment: One commenter (IV-D-05) claimed that the definition

of "process condenser" is not necessary because the term is not

used in the rule. Therefore, the commenter recommended deleting

the definition.

Response: The commenter is correct; the term “process

condenser” does not appear in the rule. Therefore, the term

“process condenser” has been deleted from the definition section

of the final rule. 

2.3.16 Process Vent

Comment: One commenter (IV-D-07) requested that the

provisions for process vents from operations that handle

materials with HAP “as impurities only” be clarified. For

example, in one of their company’s units which practices ECO as a

control technology, subsequent unit operations which provide

product treatment manage product containing small quantities of

residual epoxide, which the commenter claimed to be an impurity

at this point in the PMPU. The operation has about 15 emission

points and none of them are tied together into a manifold; to do

so would be very difficult and quite expensive. The commenter

noted that the proposal exempts these emission points from the
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process vent control requirements under §63.1420(c)(8). However,

the commenter was concerned about the requirements in §63.1425 to

manage emissions from the combination of all process vents. 

Therefore, the commenter requested that the final rule include a

clear provision to exempt process vents from equipment handling

HAP only as impurities, to address these situations. According

to the commenter, similar provisions are included in the HON,

Polymers and Resins I and IV, and other standards. The commenter

suggested that the last sentence of the definition of process

vent be modified as follows: "Process vents exclude pressure

relief valve discharges, gaseous streams routed to a fuel gas

system(s), vents from equipment that contain no organic HAP or

organic HAP only as impurities, and leaks from equipment

regulated under §63.1434."

The commenter also noted that the definition of impurity

will also have to be changed to fully accomplish this objective.

Response: Although the EPA has not taken the commenter’s

advice, insofar as editing the definitions of "impurity" and

"process vent," the EPA has added the following sentence to the

end of the definition of "process vent," which should alleviate

the commenter’s concern about the status of post-control unit

operations:

“A gaseous emission stream is no longer considered to be a

process vent after the stream has been controlled and

monitored in accordance with the applicable provisions of

this subpart.”

Comment: One commenter (IV-D-05) was concerned that the

definition of "process vent" does not have a de minimis cutoff,

as does the definition of “process vent” in the HON. Also, the

commenter pointed out that, under this rule, a process vent may

originate from any unit operation, rather than from only

specified unit operations as in the HON, and that, unlike the
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HON, this rule seems to say that the point at which a process

vent exists (and, thus, presumably where one would expect to have

to determine its characteristics) is where the stream leaves the

unit operation. To be consistent with the HON, the commenter

recommended deleting the definition and replacing it with the

following definition:

"Process vent means a gas stream containing greater than

0.005 weight-percent total organic HAP that is discharged during

operation of the PMPU. Process vents are gas streams that are

discharged to the atmosphere (with or without passing through a

control device) either directly or after passing through one or

more recovery devices. Process vents exclude relief valve

discharges, gaseous streams routed to a full gas system(s), and

leaks from equipment regulated under §63.1434." 

Response: The cutoff suggested by the commenter (0.005

weight-percent total organic HAP) has been incorporated into the

final definition of a process vent, for process vent from

continuous unit operations. This decision was based on the fact

that the EPA considers it to be impractical to impose

requirements for process vent streams with such low HAP

concentrations (less than 0.005 weight percent organic HAP). For

similar reasons, a de minimis cutoff for process vents from batch

unit operations was also added in the final rule. In the

Polymers and Resins I and IV NESHAP, the batch process vent

definition contains a de minimis cutoff of 225 kg/yr uncontrolled

HAP emissions. The EPA believes that this level is also an

appropriate de minimis level for process vents from batch unit

operations in the polyether polyols industry. The revised

definition of process vents in the final rule reads as follows:

Process vent means a point of emission from a unit operation

having a gaseous emission stream that is discharged to the

atmosphere either directly or after passing through one or

more combustion, recovery, or recapture devices. A process

vent from a continuous unit operation is a gaseous emission
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stream containing more than 0.005 weight-percent total

organic HAP. A process vent from a batch unit operation is

a gaseous emission stream containing more than 225 kilograms

per year of organic HAP emissions. Unit operations that may

have process vents are condensers, distillation units,

reactors, or other unit operations within the PMPU. Process

vents are points of emission from a unit operation having a

gaseous stream that is discharged to the atmosphere either

directly or after passing through one or more combustion,

recovery, or recapture devices. Process vents exclude

pressure relief valve discharges, gaseous streams routed to

a fuel gas system(s), and leaks from equipment regulated

under §63.1434. A gaseous emission stream is no longer

considered to be a process vent after the stream has been

controlled and monitored in accordance with the applicable

provisions of this subpart.

2.3.17 Product Class

Comment: One commenter (IV-D-07) suggested that the

definition of "product class" be modified to allow products with

similar or faster pressure decay curves to be included in the

same product class. The net result of this change would be to

allow sources to include more products in a product class with no

increase in emissions. As a result, the commenter stated that

fewer alternate scenarios and compliance tests would be required. 

Another commenter (IV-D-05) stated that the definition of

"product class" is incomplete and makes little sense unless the

reader already knows what is implied. The commenter recommended

revising the definition, as follows:

"Product class means a group of polyether polyols with a

similar pressure decay curve representing the decline in pressure

versus time. that are manufactured within a given set of

operating conditions..."

Response: The EPA modified the definition of “product

class” to include products with similar or faster pressure decay

curves, as requested by commenter IV-D-07. This change will

allow sources to include more products in a product class with no

resulting increase in emissions. The EPA has decided that
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Commenter IV-D-05's suggested revisions to the definition of

“product class” add clarity to the definition, and has

incorporated those revisions into the final rule. The definition

of “product class” in the final rule reads:

Product class means a group of polyether polyols with a

similar pressure decay curve (or faster pressure decay

curves) that are manufactured within a given set of

operating conditions representing the decline in pressure

versus time. All products within a product class shall will

have an essentially similar pressure decay decline curve,

and operate within a given set of operating conditions. 

These operating conditions are: a minimum reaction

temperature; the number of -OH groups in the polyol; a

minimum catalyst concentration; the type of catalyst (e.g.,

self-catalyzed, base catalyst, or acid catalyst); the

epoxide ratio, or a range for that ratio,; and; the reaction

conditions of the system (e.g., the size of the reactor, or

the size of the batch).

2.3.18 Purification

Comment: One commenter (IV-D-07) requested that a definition

be added for the term "purification." The commenter stated that

the proposed rule implied, but did not explicitly state, that

product purification is part of the PMPU process. As an

alternative, the commenter suggested that the definition of

"PMPU" could be modified by adding the words "and purify" to the

first sentence after the word "manufacture" in the final rule.

Response: The EPA agrees that purification of the product

was implied, but not directly stated, as being part of the PMPU

in the proposed rule. In the final rule, the EPA has revised the

third sentence in the definition of “PMPU,” so that it states

that the collection of equipment “includes purification systems,

reactors and their associated product separators and recovery

devices....”
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2.3.19 Recovery Device

Comment: Two commenters (IV-D-04, IV-D-05) asserted that the

definition of "recovery device" in the proposed rule should be

revised to be the same as the definition in the HON. Instead of

saying that recapture devices are considered to be recovery

devices "for the purpose of" monitoring, recordkeeping and

reporting requirements (as the HON does), the proposed definition

stated that recapture devices were considered to be recovery

devices "when" the rule required compliance with monitoring,

recordkeeping and recording (should be "reporting") requirements. 

The word "when" referred to time, and not purpose. The

commenters requested that the last sentence be changed to match

the HON. Once revised, the definition would read, "For purposes

of the monitoring, recordkeeping, or reporting requirements of

this subpart, recapture devices are considered recovery devices,"

rather than "When...." 

Also, the proposed definition states that reflux condensers

are part of the reactor unit operation. Commenter IV-D-04

believed that a reflux condenser on a distillation unit should be

considered part of the distillation unit operation, instead of

the reactor unit operation. The commenter recommended that the

EPA consider revising this part of the definition to simply say

that reflux condensers are part of "a unit operation in the

process unit."

Response: The definition of "recovery device" is different

for the Polyether Polyols NESHAP than for the HON because the HON

covers continuous processes, while the Polyether Polyols NESHAP

includes both batch and continuous processes. However, the EPA

agrees that the definition of "recovery device" in the Polyether

Polyols NESHAP should use the wording from the HON, so that

"when" is replaced with "for the purpose of." This change has

been made in the final rule.
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The EPA agrees with Commenter IV-D-04's comment that reflux

condensers are not necessarily part of a reactor unit operation,

and has revised the definition of “recovery device” accordingly.

2.3.20 “Start-up” and “Shutdown”

Comment: One commenter (IV-D-05) was concerned about the

fact that the definitions of "start-up" and "shutdown" in the

proposed rule were not parallel. The commenter stated that, in

the HON, considerable care was taken to make the definitions of

those two terms parallel, and that the same care is needed in

subpart PPP. The definition of "start-up" draws several

distinctions between batch and continuous processes, or unit

operations. The definition of "shutdown" does not draw those

distinctions. Thus, some equipment could be started up, but not

shut down, or vice-versa. The commenter stated that if these

distinctions are appropriate, they should be in both definitions,

worded identically. 

In addition, Commenter IV-D-05 stated that the proposed

definition of "start-up" correctly mentioned an affected source,

a PMPU, a unit operation, "or" equipment required or used for

compliance, while the definition of "shutdown" mentions an

affected source, a PMPU, a unit operation, "including" equipment

required or used for compliance. The commenter saw no reason why

these two definitions should use the words "or" and "including" 

differently, and stated that the word "including" in the proposed

definition of "shutdown" raises a problem. This wording implies

that the only type of "compliance" equipment that counts, for the

purposes of a "shutdown," would be compliance equipment included

in a unit operation. However, the commenter pointed out that

compliance equipment is seldom included in a unit operation. 

Instead, it is typically "add-on" equipment, rather than part of

the process. Thus, according to the commenter, under the

proposed definition, almost no compliance equipment could ever

have a "shutdown," although it might have occasional "start-ups." 
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Response: The EPA agrees with the commenter, and, in the

final rule the definitions of “start-up” and shutdown” read as

follows:

Shutdown means for purposes including, but not limited

to, periodic maintenance, replacement of equipment, or

repair, the cessation of operation of an affected source, a

PMPU within an affected source, a waste management unit or a

unit operation within an affected source, including

equipment required or used to comply with this subpart, or

the emptying or degassing of a storage vessel. Shutdown

does not include the normal periods between batch cycles. 

For continuous unit operations, shutdown includes

transitional conditions due to changes in product for

flexible operation units. For batch unit operations,

shutdown does not include transitional conditions due to

changes in product for flexible operation units. For

purposes of the wastewater provisions, shutdown does not

include the routine rinsing or washing of equipment between

batch cycles.

Start-up means the setting into operation of an

affected source, a PMPU within the affected source, a waste

management unit or a unit operation within an affected

source, or equipment required or used to comply with this

subpart, or a storage vessel after emptying and degassing. 

For all processes, start-up includes initial start-up and

operation solely for testing equipment. Start-up does not

include the recharging of batch unit operations. For

continuous unit operations, start-up includes transitional

conditions due to changes in product for flexible operation

units. For batch unit operations, start-up does not include

transitional conditions due to changes in product for

flexible operation units.

2.3.21 Storage Vessel

Comment: Commenters IV-D-04 and IV-D-05 stated that the

following clause (highlighted) in the definition of "storage

vessel" is unnecessary, and that it causes problems and should be

deleted from the definition: "Storage vessel means a tank or

other vessel that is used to store liquids that contain one or

more organic HAP and that has been assigned, according to the

procedures in §63.1420(f), to a PMPU that is subject to this

subpart." According to the definition, nothing can be a storage

vessel until it is assigned to a PMPU. In addition, because it
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is not a "storage vessel," it cannot be assigned to a process

unit under §63.1420(f). The commenter presented examples as to

why this clause is problematic.

Commenter IV-D-05 also recommended adding subparagraph (7)

as follows:

(7) Storage vessels assigned to another process unit

regulated under another subpart of Part 63.

Response: The EPA agrees with commenters IV-D-04 and IV-D05 on this point. The definition of “storage vessel” in subpart

PPP has been revised in the final rule as suggested (except that

the “p” in “part” is not capitalized).

2.3.22 Unit Operation

Comment: One commenter (IV-D-04) recommended that the

definition of "unit operation" in the proposed rule be revised to

say "distillation units" instead of "distillation columns." This

change was made in the HON because the unit operation may include

more than just a "column." Additionally, there may be other

equipment (such as a reflux condenser) that is part of the same

unit operation, even though it is not a "column."

Response: The EPA agrees that subpart F of the HON and

subpart PPP should be consistent in how they define a “unit

operation.” Subpart PPP has been changed to reflect the change

made via the HON amendments, as the commenter requested.
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2.4 PROCESS VENT CONTROL REQUIREMENTS

2.4.1 3 Percent Oxygen Correction

Comment: One commenter (IV-D-02) disagreed with the

proposed rule’s requirements for sources to demonstrate

compliance with outlet concentration limits in §63.1425(b)(1)(i)

and (b)(2)(ii) and §63.1426(c)(3) at a 3 percent reference oxygen

level. While 3 percent oxygen is an appropriate reference level

for boilers, the commenter claimed it is not a reasonable

requirement for thermal and catalytic oxidizers, which typically

run at around 20 percent oxygen. The effect of using a 3 percent

oxygen level is to make the standard excessively stringent for

those sources using thermal and catalytic oxidizers. The

commenter suggested that the rule allow the use of a higher

reference oxygen level for these and similar technologies.

Response: The EPA is aware of situations where the 3 percent

oxygen correction is not appropriate. However, the commenter did

not provide sufficient rationale or information to support the

claim that this cutoff was not appropriate for the polyether

polyols industry. The EPA discussed this issue with polyether

polyols producers, and found that they did not share the concern

raised by the commenter. Therefore, no change was made in the

final rule in response to this comment.

Comment: Five commenters (IV-D-03, IV-D-04, IV-D-05, IV-D07, IV-D-08) maintained that the new source MACT floor of 99.9

percent for epoxide emissions from process vents is not

appropriate. The commenters recommended that the EPA establish a

separate category for facilities that are like the facility that

was used to set the new source MACT standard (i.e., Facility M). 

The commenters elaborated that Facility M is not similar to

other sources in the source category because: 
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(a) its method of operation is substantially different from

the typical facility, resulting in significantly different

uncontrolled emissions;

(b) it has a polyether polyols production capacity many

times higher than that of other sources, and;

(c) it has two incinerators.

In regard to their claim that Facility M’s method of

operation is substantially different from a typical polyether

polyols production facility, the commenters stated that the

Agency already has adequate data to evaluate how differences in

venting may affect the emissions profile of a facility in this

source category. According to the commenters, great differences

in emissions are associated with whether a facility operates with

a closed reactor that is vented only at the end of the epoxide

feed (i.e., closed-vent), or with one that is continually or

periodically vented during the epoxide feed (i.e., open-vent). 

The commenters stated that existing data available to the EPA

demonstrate that Facility M is unlike other facilities in the

source category in that it emits significantly more epoxide to

the control devices on an essentially continuous basis. 

In addition, one of the commenters (IV-D-07) pointed out

that the high levels of uncontrolled emissions occurring during

the vented mode of operation creates a significant difference

between the ability to demonstrate very high levels of reduction

in the control device at vented and non-vented sources. 

Commenter IV-D-05 presented both a hypothetical and actual

comparison of emissions profiles from facilities that operate in

a closed-vent mode versus a similar facility venting in an openvented mode. The hypothetical case compared PO emissions, both

controlled and uncontrolled (after a water-cooled condenser) for

two reactor systems with the same physical parameters. Results

indicated that uncontrolled emissions from the vented facility

were 27 times greater than those from the nonvented facility;

however, controlled emissions (assuming 99.9 percent control for
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the vented facility and 98 percent for the non-vented facility)

were 94.5 and 84.7 lb/yr for the vented and nonvented facilities,

respectively. For the actual facility comparison, the commenter

compared the uncontrolled emission estimates of Facility M with

those from Facility I, which were reported to be similar sources. 

The commenter calculated uncontrolled emissions for Facility M

from Facility M's test report, by using the emission rates

reported during the test, and scaling these rates to 100-percent

capacity, with the assumption that both incinerators present at

Facility M were operating at 100-percent capacity at the same

time. The emission rate from Facility I were provided by a

representative of the corporation that owns Facility I, with

updated control efficiency and emissions estimates from those

originally submitted to the EPA for the MACT floor analysis for

1993. For the actual facility comparison, the uncontrolled

emissions from the vented facility were 17 times greater than

those from the nonvented facility, whereas controlled emissions

for the vented facility were 989 lb/yr and those for the

nonvented facility were 1,160 lb/yr. The commenter stated that

these analyses "confirmed the hypothesis that less effective

control gives equivalent emissions for nonvented reactors.”

Further, commenter IV-D-07 provided a comparison of two

facilities owned by the corporation that the commenter

represents. The commenter explained that both facilities have

"similarly sized units." The commenter explained that the vented

reactor produces high molecular weight polyethylene glycols and

is equipped with a refrigerated condenser, and the nonvented

reactor produces a lower molecular weight polyethylene glycol. 

The annual uncontrolled emissions were 860 lb/yr for the vented

reactor and 390 lb/yr for the nonvented reactor. The commenter

concluded that the "design considerations and emissions differ

significantly for vented and non-vented systems." 

Commenter IV-D-05 stated that explanations of the need to

subcategorize Facility M based on size and the presence of two
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incinerators was explained in detail before proposal. Commenter

IV-D-03 noted that the production capacity for Facility M is five

times larger than the average source cited in Table 2 of the

Supplementary Information Document for Proposed Standards (EPA453/R-97-010c, May 1997). Further, commenter IV-D-05 noted that

Facility M is unlike other facilities in the source category

because Facility M had two incinerators, compared to other

facilities that did not have any incinerators. 

Response: The EPA disagrees with the statement that, at

proposal, information was available to the Agency to demonstrate

that Facility M is unlike other facilities in the source category

with regard to the method of operation. Prior to proposal, an

extensive amount of information was provided to the EPA related

to the mode of operation at Facility M. However, while this

information made the EPA quite knowledgeable regarding Facility

M's mode of operation, only two of the other facilities in the

database provided any information regarding their mode of

operation. Without information about the majority of the other

facilities, it was impossible for the EPA to evaluate the

uniqueness of the mode of operation at Facility M prior to

proposal. At proposal (62 FR 46815), the EPA requested specific

information (including information on the mode of operation) from

polyether polyol facilities to allow the evaluation of whether a

subcategory was appropriate. 

In response to this request, commenters presented three

comparisons of uncontrolled and controlled epoxide emissions for

vented and nonvented facilities. The EPA appreciated these

comparisons. However, several inconsistencies and assumptions

were identified that caused the Agency to conclude that these

comparisons do not, independently, provide a sufficient basis for

subcategorizing the polyether polyols source category into vented

and nonvented subcategories. Some of EPA’s concerns with these

comparisons are discussed below.
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First, the hypothetical analysis assumed that a water-cooled

condenser was used at the reactor vent. The EPA believes that

the use of more efficient refrigerated condensers, which would

result in considerably lower uncontrolled emissions, is more

representative of practice in the industry.

With regard to the comparison of the actual facilities,

Facility I and Facility M, the EPA found that the epoxide

emission estimates used for Facility M in the commenter’s

comparison were drastically different from the emission data that

were directly submitted to the EPA by representatives of

Facility M. Also, the emission data from Facility I had been

updated from the data originally submitted during an EPA plant

site visit to that facility. The estimates provided in the

comments were lower than the original estimates due to process

improvements at the facility (that were not related to the method

of operation). The EPA conducted a similar comparison of the

uncontrolled epoxide emissions at these same two facilities using

the data originally submitted to the EPA by the two companies. 

The results were not in accordance with those presented by the

commenter. In fact, the uncontrolled emission factor for

Facility I was higher than Facility M’s factor. Clearly, the

analysis of the data available to the Agency does not support

this commenter’s analysis.

The actual facility analysis conducted by commenter IV-D-07

stated that their analysis consisted of two facilities owned by

the commenter that were "similarly sized units.” However, the

EPA found that the production capacity for the nonvented reactor

was larger than that for the vented reactor, and the emissions

were not adjusted accordingly.

Given these and other inconsistencies in the facility

comparisons provided by commenters, the EPA could not conclude

that subcategorization was necessary, based solely on these

comparisons. No commenters submitted the facility-specific data

that were requested in the proposal preamble. Therefore, even if
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the examples provided by the commenters had led to the conclusion

that subcategorization was warranted, the EPA did not have

sufficient facility information to allow a complete

subcategorization evaluation.

However, the Agency still wanted to attempt to address the

commenters’ concerns on this issue. Given the lack of data

provided by the industry prior to proposal and during the public

comment period, the EPA conducted a brief telephone survey to

inquire specifically about the mode of operation at polyether

polyol production facilities. Representatives from all the

facilities in the process vent data base were called and asked to

describe their method of venting during epoxide feed. Of the

facilities for which the EPA was able to collect mode-of-venting

data, 24 percent (including Facility M) reported venting during

the epoxide feed step, and 76 percent reported that their

facilities did not vent during the epoxide feed step. Therefore,

the EPA concluded that the manner of operation of facility M was

not unique to the source category, as claimed by the commenters.

The EPA sought to determine whether the different venting

modes during epoxide feed resulted in "differences in the amount

and pattern of emissions and the achievable degree of emission

reduction," (Memorandum, from Seaman, J.C., EC/R Incorporated to

Svendsgaard, D, EPA/OCG. January 15, 1999. Documentation of the

Calculation of Uncontrolled Emission Factors. Docket Item: IV-B01). The EPA determined that a facility's uncontrolled emission

factor (mass emissions per mass of polyol product produced) was

the best method of comparison, and calculated such a factor for

each facility for which sufficient information was available. 

For the "vented" facilities, the median uncontrolled emission

factor was 0.17 (lb HAP emissions per 1000 lb of product). The

data points were considered to have too varied a distribution,

with two orders of magnitude making up the difference between the

highest and lowest emission factor, for the mean value to be an

adequate representation of central tendency. For the "nonvented"
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facilities the median uncontrolled emission factor was 1.09. The

commenters asserted that uncontrolled epoxide emissions at vented

facilities are considerably higher than those at nonvented

facilities. However, the results of the EPA’s analysis, based on

the best information available, clearly do not support this

assertion, since the median uncontrolled emission factor

calculated for nonvented facilities is over six times higher than

the median uncontrolled emission factor for vented facilities.

In conclusion, based on all of the information available to

the Agency, the EPA was unable to determine a different emission

trend between the vented and nonvented groups from the data made

available to the Agency between proposal and promulgation. 

Therefore, the EPA did not subcategorize the industry based on

the method of operation.

The commenters' second rationale to support their claim that

Facility M is not a similar source was that the production

capacity at Facility M is many times that of other sources in the

source category. Subcategories, or subsets of similar emission

sources within a source category, may be defined if technical

differences in emissions characteristics, processes, control

device applicability, or opportunities for pollution prevention

exist within the source category (Federal Register, Vol. 57, No.

137, Initial List of Categories of Sources Under Section

112(c)(1) of the Clean Air Act Amendments of 1990). The EPA does

not believe that the fact that Facility M has a larger production

capacity satisfies any of these criteria. Further, since one

facility in the process vent database has a capacity that is 83

percent of Facility M's capacity, the EPA also disagrees that the

production capacity is unique.

The third argument given by the commenters to support the

claim that Facility M is not similar to the other affected

sources, was that Facility M has two incinerators, and that no

other sources have incinerators. The EPA disagrees with the

commenters' claim that Facility M is the only source with an
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incinerator, since there is another facility in the database that

also uses incineration. Further, the fact that a source has a

better control than all other facilities in the source category

through the use of one or more incinerators is not a sufficient

basis for asserting that the source should be subcategorized. 

The purpose of MACT is to ensure that regulated sources meet the

control standards achieved by the best performing sources in the

category. Subcategorization on the basis of the control

technology utilized would undermine the very concept of MACT. 

In addition to the evaluation of the individual points

raised by commenters, the EPA also considered whether these

characteristics of Facility M collectively form a basis for

subcategorization. The EPA concluded that, based on the

facility-specific process, emissions, and emissions control

information provided to the Agency by the polyether polyol

industry, a separate subcategory should not be created solely for

Facility M.

Comment: Three commenters (IV-D-04, IV-D-05, IV-D-08)

requested that the combustion efficiency be set at 98-percent,

with a 20 ppmv concentration cutoff, for new sources for this

source category, to be consistent with the policy established for

other MACT standards as well as with data furnished to the EPA. 

The commenters referred to other MACT standards, including the

HON, where the EPA has exercised such discretion. They stated

that the EPA had selected the 98-percent or less efficiency level

in some of the other source categories despite individual test

results indicating that greater than 98-percent reduction could

be achieved under specific test conditions. One commenter (IV-D08) noted that the EPA (in the HON) has required new source

controls for chemical industry process vents to meet a 98-percent

emission reduction, recognizing that a 99.9-percent control

efficiency was not achievable for these industries (see HON BID,

Section 12, page 2). One commenter (IV-D-03) asserted that the
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overall expected emission reduction from a new source MACT of

99.9-percent, as opposed to 98-percent, would be trivial, even if

uniformly applied to all sources nationwide. 

Response: The EPA disagrees with the commenters' statement

that the EPA has an "established policy" that the combustion

efficiency be set at 98-percent. The EPA has no such policy,

even though previous rules may have established 98-percent

destruction efficiency as the standard, along with a 20 ppmv

alternative. However, more important than a precedent set by

previous rules, was the test data provided by the facility used

to set the MACT floor level of control for epoxide emissions from

new sources, Facility M, and the permit conditions with which the

facility must comply. The EPA has a responsibility to scrutinize

the test and permit data, and use it in setting a standard,

whenever possible. Therefore, the EPA could not simply go by the

precedent set on other rules since the EPA had test data and

permit conditions from Facility M that could not be ignored. 

Further, the test data provided by Facility M were calibrated to

the predominant epoxide in the vent stream, and EO and PO were

the overwhelmingly predominant HAP in the process vent stream. 

This situation is unlike the HON. Since the HON regulated such a

large number of HAP, even if an individual facility had a tested

and reported destruction efficiency greater than 98 percent, this

destruction efficiency could not be generalized to all the HAP

regulated by the HON, due to the large variety of flammability

characteristics of the HAP at HON facilities. The EPA could not

address the commenters' statement regarding information the EPA

had available to set the MACT floors in "other MACT standards,"

since the commenter did not make specific references. 

Comment: Two commenters (IV-D-03, IV-D-07) explained that

the combustion technology utilized by Facility M results in an

increase in criteria pollutants (CO2 and NOx), which were not
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included in EPA’s MACT floor analysis, while alternative control

technologies, such as scrubber or extended cookout, would be

expected to cause significantly lower NOx emissions. 

Additionally, the commenters claimed that the EPA has failed to

account for potential process safety considerations associated

with the combustion of EO, noting that explosions at a number of

facilities that use or produce EO have already prompted the EPA

to delay enforcement of the December 6, 1994 air toxics rule for

EO sterilization facilities. Commenter IV-D-07 added that the

EPA should encourage standards that can be met using noncombustion control strategies (achieving 98-percent reduction). 

Response: The EPA is aware that incineration has secondary

criteria pollutant emissions. However, MACT floor decisions are

based on the reduction of HAP emissions, and cannot be based

primarily on their secondary impacts. The EPA is aware that the

use of incineration, resulting in an increase in sulfur dioxide

emissions, which may trigger Prevention of Significant

Deterioration(PSD) and/or New Source Review (NSR). The EPA has

addressed this issue in previous NESHAP, by referring to a July

1, 1994 guidance memorandum issued by the EPA (available on the

Technology Transfer Network; see “Pollution Control Projects

(PCP) and New Source Review (NSR) Applicability” from John S.

Seitz, Director, OAQPS to EPA Regional Air Division Directors). 

In this memorandum the EPA provided guidance for permitting

authorities on their ability to approve PCP exemptions (from PSD

review and major NSR) for source categories other than electric

utilities that use add-on controls and fuel switches to less

polluting fuels. In the July 1, 1994 guidance memorandum, the

EPA specifically identified the combustion of organic toxic

pollutants as an example of an add-on control that could be

considered a PCP and an appropriate candidate for a case-by-case

exclusion from major NSR. The EPA is alert to potential NSR 
2-62

conflicts, and feels that this memorandum will alleviate most

NSR/PSD review concerns. In the event that it will not, the EPA

will attempt to create implementation flexibility on a case-bycase basis.

The EPA does consider secondary impacts such as water

pollution, energy costs, costs to control, and emission of air

pollutants other than the 188 HAP in developing a MACT standard. 

The estimated secondary impacts are presented in the proposal

SID. Further, the safety issues of incineration of epoxides were

adequately addressed at Facility M and the other facility in the

database that has incineration. Therefore, the EPA did not find

these reasons to be sufficient to justify eliminating Facility

M's data from the determination of the MACT floor for new sources

based on the fact that Facility M uses incineration. 

Comment: Two commenters (IV-D-05, IV-D-08) maintained that

data from Facility M do not support the new source standard

because the Agency used State permit information and

corresponding performance test reports for Facility M. They

claimed that these data were submitted to the State agency to

demonstrate compliance with permit emission limitations for VOCs,

not HAPs, and to document that the incinerators were meeting the

required VOC destruction efficiency. They noted that there are

several significant inconsistences between the test reports and

the proposed standards (these inconsistencies were discussed in

more detail under section 2.1.6, Test methods and procedures). 

The commenters concluded that Facility M itself has not

demonstrated that it is able to meet the proposed rule’s epoxide

emission limits, noting that the rule requires Method 301

validation of Method 25A and Facility M did not perform

validation by Method 301.

Response: The EPA disagrees with the commenters' statement

that the data from Facility M do not support the new source
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standard because the performance test was conducted to determine

VOC destruction efficiency instead of epoxide, and the permit

conditions are for VOC. The primary pollutant in the stream was

PO, and this is the pollutant for which Method 18 at the inlet of

the incinerator, and Method 25A at the outlet of the incinerator,

were calibrated. Therefore, even though the test and permit cite

VOC destruction efficiency, it is clear that it is the

destruction of PO that was tested and regulated at Facility M. 

The commenters' concerns about inconsistencies between the

test reports and the proposed standards are discussed in section

2.1.6 of this document. In summary, the performance test

performed by Facility M is consistent with the performance test

requirements in the final rule. 

Comment: Two commenters (IV-D-04, IV-D-05) requested that

the EPA clarify that, in all instances, two or more devices in

combination may be used to meet an emission limitation. For

example, commenter IV-D-04 stated that Facility M has two

incinerators, and there may be other facilities that use a

combination of control devices or recovery devices to achieve

emission limitations. Both commenters requested that the EPA

clarify, both in §63.1431(e) and in the preamble for the final

rule, that combinations of devices are permissible. The

commenters also recommended the following revision in §63.1431(e)

and the first sentence in §63.1431(e)(1): 

"(e) Compliance with the epoxide emission factor limitation

through the use of extended cookout in conjunction with a one or

more combustion, recovery, and/or recapture devices. (1) The

owner or operator shall notify the Agency of the intent to use

extended cookout in conjunction with a one or more combustion,

recovery, and/or recapture devices to comply ...."
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Response: The Agency intended to allow for multiple control

techniques in series, and has amended §63.1431(e) as recommended

by the commenters. 

2.4.2 A Concentration Limit as an Alternative Process Vent

Emission Limit

Comment: In response to EPA’s request for comments on the

determination of an alternative concentration limit for new

source process vents (§63.1425(b)(1)(ii)), four commenters (IV-D03, IV-D-05, IV-D-07, IV-D-08) recommended a 20-ppm cutoff

concentration limit. Two commenters (IV-D-03 and IV-D-05)

agreed that there was ample data available to EPA to support this

limit. One commenter (IV-D-03) referred to HON stack emission

test data submitted to EPA Region IV and an attached emissions

summary table taken from the test report, which they believed

supported their claim. The commenter noted, however, that these

data were generated to demonstrate HON compliance for a

continuous process, which may not be equivalent to the expected

performance of a batch process to be regulated under the

Polyether Polyols Production NESHAP. 

Commenter IV-D-05 pointed to the HON compliance trials as

proof that the 20-ppmv concentration limit used in the HON is a

conservative value as an alternative to the new source MACT

standard and should be adopted in this standard, regardless of

whether a 98 or 99.9-percent efficiency limit is established. 

This commenter noted that a 20-ppmv cutoff is recognized as

appropriate in other MACT standards, and in most NSPS standards

that apply to process vents from the chemical industry. Because

most facilities in this source category use batch processes, the

commenter asserted that a lower concentration cutoff will be

difficult to develop, demonstrate compliance with, and enforce in

a practical manner. 

Commenter IV-D-07 supported the comments of commenter IV-D05, and added that from a source owner/operator perspective,
2-65

compliance with the 20-ppmv criteria is significantly simpler to

demonstrate than compliance with the 98-percent reduction, since

only the outlet from the control device needs to be tested to

demonstrate compliance with the 20-ppmv criteria. In addition,

the compliance difficulties that might result from owners and

operators comparing two measured numbers would be eliminated, and

problems in sampling and analyzing highly variable streams from

batch process vents containing significant concentrations of

epoxides would be eliminated, by allowing the 20 ppmv cutoff

concentration limit. 

The commenter (IV-D-07) also provided another reason to

support an alternative concentration limit of 20-ppmv for new

sources. In the Boiler and Industrial Furnace Interim rules, EPA

has established a precedent where a 20-ppmv hydrocarbon limit is

used as a compliance limit for certain systems required to comply

with a destruction efficiency greater than 99.9 percent. The

commenter concluded that a 20-ppmv concentration limit is an

acceptable control level for both combustion facilities and

uncontrolled and non-combustion control devices, and that it is

justified for both new and existing sources. 

One commenter (IV-D-08) supported the reasons above to

maintain a 20-ppmv concentration cutoff, and added that the EPA

has previously stated that 20 ppmv is the lowest outlet

concentration of total organic compounds achievable by combustion

of low organic concentrations (reference was made by the

commenter to the preamble to the NSPS for subpart NNN).

In addition, this commenter cited the following reasons for

not establishing a concentration limit of 1 ppmv for new source

process vents:

(1) A concentration limit of 1 ppmv may not be achievable by

combustion over the long compliance duration required by the

rule;

(2) A concentration limit of 1 ppmv would be closer to the

analytical detection limit, and have greater uncertainty would be
2-66

associated with the analytical results than there would be with a

concentration limit of 20 ppmv.

Response: The Agency agrees with Commenter IV-D-08's

statement that the EPA previously stated that 20 ppmv is the

lowest outlet concentration of total organic compounds achievable

by combustion of low organic concentrations (an inlet

concentration of 2000 ppmv), referencing the preamble to the

proposed NSPS for Air Oxidation Unit Process (48 FR 48932,

October 21, 1983). As stated in subpart NNN's preamble, the

outlet concentration of 20 ppmv was established based on kinetic

calculations of incinerators. It was demonstrated that, at a

given temperature and residence time, a stream with a low inlet

concentration (approximately 2000 ppmv) could not demonstrate an

outlet concentration below 20 ppmv. Further, in the preamble to

the proposed amendments to the HON (61 FR 43698, August 26,

1996), the EPA expanded the application of this lower bound

concentration performance standard to control/recovery devices

other than incinerators. The HON's preamble explained that

recovery devices are designed to typically reduce emissions to

the same outlet concentration level given a relatively wide range

of inlet concentrations. When the inlet concentration is

substantially below the design maximum leading conditions (and

begins to approach the residual level in the outlet stream) the

recovery device efficiency will decrease. Therefore, the final

rule contains an alternative concentration limit of 20 ppmv for

both new and existing sources. 

At proposal, the existing source concentration limit was 20

ppmv of total epoxides. In evaluating the new source limitation,

the EPA considered whether this limitation should be “total

epoxides or TOC.” Other rules, such as the HON, allowed the

option of determining outlet concentration limits on a TOC basis. 

Since the EPA desired to allow Method 25A (which is designed to

measure TOC) to determine compliance with this concentration
2-67

limit, and since other standards allowed the option of compliance

on a TOC basis, the concentration limits in the final rule for

new and existing sources are 20 ppmv total epoxides or TOC.

Comment: One commenter (IV-D-07) advocated that the

alternative 20-ppmv concentration limit should apply more broadly

to process vents without controls. For example, there might be

vents from equipment practicing a very long extended cookout or

vents from equipment where the epoxide content is very low and

emissions are very small. The commenter noted a variety of

precedents in MACT standards (particularly the HON) applying to

chemical industry sources, to support the concept of making the

limit broadly applicable.

Response: First, the commenter is incorrect in stating that

the HON allows a 20-ppmv concentration limit for process vents

that do not control. Paragraph §63.113(a) in the HON specifies

the control devices and recovery devices that are permissible for

achieving the 20-ppmv concentration limit.

The 20 ppmv outlet concentration limit recognizes that there

is a lower outlet concentration boundary, below which combustion,

recapture and control devices cannot achieve when the inlet to

the device is below approximately 2000 ppmv. The EPA understands

that the outlet concentration after extended cookout may be as

low as that after a combustion, recovery, or recapture device. 

However, this is not based on technological limitations of ECO,

as is the basis for the 20 ppmv concentration limit for

combustion, recovery, and recapture devices. Therefore, the EPA

believes that allowing the 20 ppmv concentration limit for ECO is

not appropriate.

Further, the EPA does not believe that it is appropriate to

use this alternative concentration requirement as a de minimis

cutoff for vents where the epoxide content is very low and

emissions are very small. The EPA believes that the HAP
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concentration and emission de minimis cutoffs in definition of

the process vent (discussed above in Section 1.2.3) adequately

address these vents.

2.4.3 Basis for Outlet Concentration Testing as an

Alternative Process Vent Limit 

Comment: One commenter (IV-D-05) strongly supported the

level for existing sources and the use of alternative cutoff

levels in §63.1425(b)(2)(ii). However, the commenter noted that

the word "average" in §63.1425(b)(2)(ii), which was between

"outlet" and "concentration" in a draft version of the proposed

rule that was shared with industry, has been deleted. This is a

significant change for batch processes. According to the

commenter, a 20-ppmv average outlet concentration is a much

different limit than a 20-ppmv maximum outlet concentration. 

When a reactor is vented down, the initial concentration will be

high, decreasing as the venting continues. The overall vent in a

given situation may well meet the 20-ppmv average, but be

significantly above this limit for a short portion of the venting

period. Also, the commenter noted that §63.1425(b)(2)(ii) unlike

§63.1425(b)(2)(i), does not include "process vents." Since this

paragraph is in a section dealing with process vents, the

commenter believed that it was the EPA’s intent to include them

in this paragraph. Therefore, the commenter recommended revising

the text, as follows:

"Maintain an average outlet concentration for process vents

of total epoxides...." 

Response: The word "average" between "outlet" and

"concentration" was deleted in the proposed rule from a draft

shared with the public because the term was inappropriate at that

location. Initial compliance is determined by the procedures

specified in §63.1426(c)(3), which in turn cites Method 18. For

process vents from continuous unit operations Method 18 is
2-69

conducted for 3, 1-hour runs; for process vents from batch unit

operations Method 18 is conducted during worst-case conditions. 

The term "average" comes into play in relation to continuous

compliance. For continuous compliance, a daily average must be

maintained. This daily average can be determined using either

CEMS data or parametric monitoring data. Further, the word

"average" was not used in any of the other subsections of

§63.1425(b)(1) or (2), for the same reason.

2.4.4 Group Determination for Nonepoxide HAP Process Vent

Emissions on a Vent-by-Vent Basis

Comment: Three commenters (IV-D-04, IV-D-05, and IV-D-08)

requested that owners or operators have the option of making the

group determinations for nonepoxide process vents on a vent-byvent basis, rather than being required to do the group

determination for the combination of all process vents. The

commenters maintained that the distinction between Group 1 vents

(requiring control) and Group 2 vents (not requiring control) is

essentially a cost-effectiveness decision borrowed, in this rule,

from previous MACT standards such as the HON. However, all

previous MACT standards that have required Group determinations

for process vents have specified that the determinations be

conducted on individual vents. According to the commenters, the

EPA appears to be borrowing those same equations and criteria,

and employing them in a totally different context, without making

the adjustments that would be necessary for that context. One of

the commenters also noted that there was no supporting rationale,

and lacks legal justification for setting the MACT floor level of

control more stringent than any other MACT standard that

previously used these Group Determination equations. Commenter

IV-D-08 maintained that the proposed rule sets a dangerous

precedent for future MACT standards that might impact the

chemical industry.
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These commenters also expressed the following specific

objections to this approach. 

(1) Commenter IV-D-08 stated that the use of an aggregated

vent approach implies that all process vents in a unit are

manifolded to a common control device. The commenter reported

safety and construction concerns if this were the case. 

(2) Commenter IV-D-04 asserted that Group determinations for

combinations of process vents would be excessively biased toward

finding vents to be Group 1. For example, a threshold flow rate

of 0.005 standard cubic meters per minute may be realistic for

deciding the cost-effectiveness of controlling an individual

process vent, but it would be virtually impossible to find any

process unit having such a low flow rate for the combination of

all its process vents. 

(3) Commenter IV-D-8 expressed concern that the proposed

rule does not provide for appropriate batch process applicability

cutoffs, such as annual emission limits and cutoff flow.

(4) Commenter IV-D-04 claimed that by using the combination

of process vent Group determination approach, the EPA would

provide a disincentive to the very type of emission reduction

efforts which, in previous rules such as the HON, were a desired

outcome. For example, under the HON an owner or operator is

allowed to make process changes that increase the TRE index

value. However, the proposed rule provides no incentive for

making beneficial changes to a single process vent unless there

is a realistic chance to get the TRE index value into Group 2 for

the combination of all process vents. The commenter stated that

there is virtually no chance that a process change could make the

entire combination of vents Group 2. 

In order to address these concerns, the commenters made

several suggestions. Commenter IV-D-04 suggested that the EPA

either validate the "borrowed" equations and criteria in the

context of combined process vents, or develop and validate

entirely new equations and criteria, in order to allow Group
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determinations to be established based on "combinations" of

process vents. Commenter IV-D-05 suggested that the EPA simply

allow owners and operators to conduct group determinations on a

vent-by-vent basis.

Response: The EPA agrees with the statement that the Group 1

criteria is essentially a cost-effectiveness decision. The EPA

also agrees that the criteria in subpart PPP were borrowed from

other MACT standards, specifically the HON (for process vents

from continuous unit operations) and Polymers and Resins I and IV

(for process vents from batch unit operations).

The EPA agrees that the TRE index approach was developed

for, and has been applied on, individual vents. Therefore, the

EPA further agrees that in order to apply the TRE approach to the

combination of process vents from continuous unit operations in a

PMPU is not appropriate without conducting an analysis to

validate the equations for the combination of vents, or to

develop new equations. Rather than take this approach, the EPA

decided to apply the Group 1 criteria for process vents from

continuous unit operations that use nonepoxide organic HAP to

make or modify the product to individual process vents.

For process vents from batch unit operations that use

nonepoxide organic HAP to make or modify the product, the Group 1

equations are the same equations employed in the Polymers and

Resins I and IV MACT standards (40 CFR 63, subparts U and JJJ,

respectively). The EPA agrees with the commenters that in the

polymers and resins standards, the Group criteria are applied to

individual vents. However, unlike the TRE for process vents from

continuous unit operations, the group determination approach that

is used in subparts U, JJJ, and PPP, was originally developed to

be used for either individual vents or the combination of vents.

The original source of the batch vent group determination

approach is the EPA document "Control of Volatile Organic

Compound Emissions From Batch Processes - Alternative Control
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Techniques Information Document" (EPA-453/R-94-020), i.e., the

Batch ACT. On page 7-5 of this document, the EPA states “The

control option requirements presented in Chapter 6 apply to (1)

individual batch VOC process vents to which the annual mass

emissions and average flowrate cutoffs are applied directly, and

(2) aggregated VOC process vents for which a singular annual mass

emission total and average flowrate cutoff value is calculated

and for which the option is applied across an aggregate of

sources.” Therefore, for process vents from batch unit

operations, the EPA disagrees with the statements that the group

determination equations are being used “in a totally different

context” and that there is no supporting rationale for using

them. The final rule retains the requirement that the Group

criteria be applied to the nonepoxide organic HAP emissions from

the combination of process vents from batch unit operations

associated with the use of nonepoxide organic HAP to make or

modify the product.

With regard to the specific concerns raised by the

commenters, the EPA does not agree that applying the group

criteria to the combination of process vents in a PMPU implies

that all process vents are manifolded together. The EPA clearly

recognizes that not all process vents are manifolded together,

and that there could be safety and construction concerns with

doing so. Applying the group criteria to the combination of

vents means that the decision whether to control process vents in

the PMPU is based on the characteristics of all process vents. 

If the combination of process vents is determined to be Group 1,

the EPA believes the rule provides considerable flexibility to

the owner or operator in how to achieve the specified emission

reduction for emissions from all process vents. There is no

requirement that any process vents be combined.

The examples provided in second and fourth concerns are

specific to the Group 1 criteria for process vents from

continuous unit operations. As noted earlier, the EPA has
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changed the final rule so that the group criteria for these vents

is applied on an individual vent basis. Therefore, the examples

should no longer be of concern.

With regard to the third concern, the commenter indicated

that the proposed rule did not include “appropriate batch

process applicability cutoffs, such as annual emission limits and

cutoff flow.” At §63.1428(c), the proposed rule did have an

annual emission limit cutoff of 11,800 kilograms per year. 

Therefore, if total nonepoxide organic HAP emissions from all

process vents from batch unit operations that use nonepoxide

organic HAP to make or modify the product were less than 11,800

kilograms per year, the combination of process vents would be

Group 2. The proposed rule also contained the concept of a

“cutoff flow rate” at §63.1428(e). The cutoff flow rate is

calculated from the annual nonepoxide organic HAP emissions, and

compared to the actual flow rate. In addition to these

“cutoffs,” which are retained in the final rule, the EPA has

clarified, in the definition of process vent, that process vents

from batch unit operations must have annual organic HAP emissions

of 250 kilograms per year or greater.

In conclusion, the EPA agrees with the commenters that the

group determination for process vents from continuous unit

operations that use nonepoxide organic HAP to make or modify the

product should be made on an individual vent basis, and has

modified the final rule accordingly. However, the EPA disagrees

that the group determination for process vents from batch unit

operations that use nonepoxide organic HAP to make or modify the

product should be on an individual vent basis. The final rule

requires that this group determination be made on the combination

of all batch vents in the PMPU.

Comment: One commenter (IV-D-04) stated that the proposed

rule's requirement for separate Group determinations for

continuous process vents and batch process vents is inconsistent
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with the real-life scenario in which the two types of vents are

ducted together. Criteria such as HAP concentrations, flow

rates, etc. can be determined on a vent-by-vent basis, but the

commenter is unsure how to determine them for a combination of

batch and continuous vents, and the proposed rule does not

explain how to do this. The solution suggested by Commenter IVD-05 involved revising §63.1424(b) as follows: 

"(b) When emissions of different kinds (i.e., emissions

from process vents subject to §63.1425 through §63.1430,

storage vessels subject to §63.1432, process wastewater,

and/or in-process equipment subject to §63.149 of subpart G)

are combined, and at least one of the emission streams would

require control according to the applicable provision (e.g.,

is Group 1, or where applicable, belongs to a combination of

process vents that is Group 1) in the absence of combination

with other emission streams, the owner or operator shall

comply with the requirements of either paragraph (b)(1) or

(b)(2) of this section." 

Response: The EPA agrees that the final rule needed more

specific requirements for streams that have been ducted together

or otherwise combined. However, the commenter’s suggested rule

language and their actual comment referred to two different

situations. The comment cited concerns with how to conduct the

group determination for combined streams, but the paragraph that

the commenter suggested language for, §63.1424(b), specified how

to control combined streams. The EPA made changes to address

these concerns in both of these instances. 

As requested by the commenter, the final provisions in

§63.1424(b) state how to comply for combined streams from

different types of emission points; however, the EPA selected a

more straightforward approach. Paragraph §63.1424(b) of the

final rule states that when emission streams are combined, the

owner or operator has the option to comply with the individual

requirements for each type of emission stream in the combined

stream, or to comply with the most stringent requirement for any

stream in the combined stream.
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In order to provide guidance regarding Group determinations

in combined streams, the EPA found it necessary to add new

requirements, as §63.1428(i). Paragraph §63.1428(i) specifies

that the Group determination for a stream containing a

combination of process vents from batch unit operations and

process vents from continuous unit operation, both associated

with the use of a nonepoxide organic HAP to make or modify the

product, shall be determined as for any other process vent from a

continuous unit operation, except that the TRE must be calculated

when nonepoxide organic HAP emissions are being generated by the

batch unit operation that feeds into the combined stream.

In making this change to the final rule, the EPA also

realized that clarification was needed with regard to when the

owner or operator should collect the information needed to make a

Group determination for uncombined process vents from batch unit

operations, or from continuous unit operations, as well. As a

result, §63.1428(a) has been revised to state that if the owner

or operator is using a combustion, recovery, or recapture device

to reduce epoxide emissions from process vents from batch unit

operations, then the location at which the annual uncontrolled

nonepoxide organic HAP emissions and annual average flow rate are

determined must be at the exit of the combustion, recovery, or

recapture device. 

In addition, §63.1428(h)(1) has been revised to provide

specifications regarding where the owner or operator must conduct

the TRE index value determination. This location is after the

last nonepoxide recovery device, if the owner or operator uses

one or more nonepoxide recovery devices after all control

techniques to reduce epoxide emissions; at the exit of at the

exit of the combustion, recovery, or recapture device, if the

owner or operator does not use a nonepoxide recovery device after

a combustion, recovery, or recapture device to reduce epoxide

emissions; or at the exit from the continuous unit operation, if

the owner or operator does not use a nonepoxide recovery device
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after extended cookout to reduce epoxide emissions. The TRE

index value is one of the factors that determines the Group

status of a process vent from a continuous unit operation,

according to the final definition of Group 1 continuous process

vent in §63.1423.

2.4.5 Relationship to Polymers and Resins I Changes

Comment: One commenter (IV-D-04) noted that the proposed

requirements for batch process vents were borrowed from the Group

1 Polymers and Resins standard, which is in litigation. 

Therefore, the commenter requested that, when the result of the

Polymers and Resins Group 1 litigation is final, the EPA take

additional public comments on the concept of incorporating any

changes to that rule into this rule.

Response: The EPA agrees with the commenter, and the

preamble for the proposed amendments to the Group 1 Polymers and

Resins NESHAP (64 FR 11560, March 9, 1999) requested comments on

the concept of applying the amended batch requirements

automatically to other subparts that reference the Group 1

Polymers and Resins NESHAP.

2.4.6 Group Redetermination

Comment: One commenter (IV-D-04) maintained that reducing

production capacity or production rate should not trigger

mandatory redetermination of process vent Group status, as

proposed. The commenter stated that decreasing the production

rate or production capacity would not be expected to move process

vents from Group 2 to Group 1, since typically emissions decrease

with decreases in production. Therefore, the commenter suggested

that §63.1428(g)(1) and (h)(2) be revised as follows:

"Examples of process changes include, but are not limited

to, increases changes in production capacity, or production

rate, changes in feedstock type, or catalyst type,; or ...."
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Response: The EPA agrees with the commenter, and has

incorporated the suggested changes into the final rule.

2.4.7 Non-epoxide versus Epoxide Process Vent Emission Limits

Comment: One commenter (IV-D-05) stated that, in the

process vent control requirements of §63.1425(a), it is not clear

whether emissions of epoxides would be subject to one emission

limit or two. The first emission limit is specifically for

epoxide emissions. The second emission limit is for "organic HAP

emissions resulting from the use of nonepoxide organic HAP (in

addition to epoxides) to make or modify the polyether polyol

product." Since epoxides are organic HAP, it appears that they

may be included in the term "organic HAP emissions" in the second

emission limit. The commenter thought that the EPA intended for

the first emission limit to cover epoxides, and for the second

emission limit to apply only to non-epoxide organic HAP. To make

this clear, the commenter recommends revising the text, as

follows: 

“...paragraph (c) of this section contains limitations for

nonepoxide organic HAP emissions resulting from the use of

nonepoxide organic HAP (in addition to epoxides) to make or

modify the polyether polyol product;...”

Response: The Agency agrees that the proposed language was

confusing, and has made the suggested change to the final rule.

2.4.8 Alternative Emission Factor

Comment: One commenter (IV-D-05) supported the inclusion of

an alternative emissions factor as proposed by the EPA for

process vents from new and existing sources. However, the

commenter urged the EPA to clarify [in §63.1425(b)] that owners

and operators may choose to demonstrate compliance by meeting the

appropriate control efficiency, by maintaining outlet

concentrations on individual process vents, or by maintaining the
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PMPU-wide emission factor. The commenter pointed out that the 

emission factor in §63.1425(b)(1)(iii) and (b)(2)(iii) is not

expressly limited to process vents, and instead is "PMPU-wide,"

which could be mistaken to include equipment leaks, such as minor

emissions from flanges or valves, plus any emissions from

wastewater, storage vessels, etc. Since these PMPU-wide emission

factor limits are meant to apply to process vent emissions, the

commenter suggested minor changes to §63.1425(b)(1)(iii) and

(b)(2)(iii) to clarify their intent, as follows:

(1) ***

(iii) Maintain an a PMPU-wide emission factor of no greater

than 4.43 X 10-3 kilogram epoxide emissions per megagram of

product for all process vents in the PMPU.

* * * * *

 (2)***

(iii) Maintain an a PMPU-wide emission factor of no greater

than 1.69 X 10-2 kilogram epoxide emissions per megagram of

product for all process vents in the PMPU."

Another commenter (IV-D-07) also requested that these

paragraphs be clarified, for the same reasons presented above. 

This commenter’s suggested revision to these paragraphs was

slightly different: 

"Maintain a PMPU-wide emission factor for process vents of

no greater than...."

Response: The Agency agrees with the commenters, and has

changed §63.1425(b) in accordance with Commenter IV-D-05's

suggestions. However, please note that proposed

§63.1425(b)(2)(iii) is §63.1425(b)(2)(iv) in the final rule.

2.4.9 Batch/Continuous Process Units versus Batch/Continuous

Unit Operations

Comment: To be consistent with the definitions provided in

§63.1423(b), one commenter (IV-D-05) recommended changing the

terms in §63.1425(b) as follows: "... batch process unit

operation" and "continuous process unit operation."
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Response: The EPA agrees that “batch process unit operation”

and “continuous process unit operation” were redundant terms, and

that the word “process” was not necessary in those phrases. The

Agency appreciates the comment and has revised these phrases in

the final rule, as suggested by the commenter. 

2.4.10 Controls for New Source Process Vent Emission Limits

Comment: One commenter (IV-D-05) stated that it is not clear

in the proposed rule that new sources may use extended cookout as

a mechanism to meet the epoxide emission limits, and, therefore,

the commenter recommended that a sentence be added at the end of

§63.1425(b)(1) as follows:

"Extended cookout may be used to meet any of these

standards."

Response: The extended cookout control options are

contained in §63.1427. The Agency does not think that it is

appropriate to single out extended cookout in §63.1425(b)(1), as

suggested by the commenter.

2.4.11 Calculation Methods for Emissions from Batch Operation

Units

Comment: One commenter (IV-D-07) noted that, in order to

verify compliance with the emission factor limits for process

vents, the owner or operator is required to calculate annual

epoxide emissions and divide the emissions by the annual

polyether polyol production rate. Emissions from batch

operations are calculated based on the procedures in

§63.488(b)(1) through (b)(7) of subpart U. The commenter

requested that the EPA, in order to avoid duplicative work and

duplicate data sets for the same emission points, make it easy

for facility owner/operators to use the alternative engineering

assessments contained in §63.488(b)(6) of subpart U to estimate

emissions. That is, §63.488(b)(6)(ii)(B) of subpart U should
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specifically state that other methods of estimating emissions,

such as those used for past permit applications, emission

inventories, or SARA 313 reports, may be used as part of the “any

other means” mentioned in §63.488(b)(6)(ii)(B). 

Response: The EPA does not consider it necessary to clarify

the meaning of the phrase "any other means." However, under the

proposed amendments to subpart U, the promulgated requirements

found in §63.488(b)(6)(ii)(B) have been removed, and greater

latitude is offered to owners and operators by allowing them an

open-ended ability to “request approval” to use engineering

assessment (including the use of previous test results, as long

as the previous test was conducted under conditions that are

representative of current operating conditions), via proposed

§63.488(b)(6)(i)(C). This proposed amendment, if promulgated,

should reduce the amount of “duplicative” work for owners and

operators, which should appease the commenter’s concern (as

stated above). Further, the EPA is seeking comments on the

impact of the proposed subpart U amendments on polyether polyol

facilities in the notice announcing these proposed amendments.

2.4.12 Continuous Unit Operations Group Determinations

Comment: One commenter (IV-D-05) stated that the regulatory

text in §63.1428(h) does not provide a flow rate or concentration

cutoff (these are included in the Group 1 process vent definition

of subpart G) and refers only to §63.115(d) of the HON, which

addresses the determination of the TRE index value. Further, the

proposed rule is not consistent with the proposed preamble (62 FR

46810) because it does not completely state how to make the Group

1 determination for continuous processes. The commenter

recommended revising this section to include appropriate

language.
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Response: The Agency agrees that, as proposed, subpart PPP

was unclear about flow rate and concentration cutoffs, for the

purpose of determining whether or not a “combination of process

vents” was Group 1. Since proposal, the EPA revised the Group

determination for process vents from continuous unit operations,

so that the group determination is conducted on an individual

vent basis (see Section 2.4.4 of this document). Therefore, the

definition of “combination of process vents that are Group 1" was

revised to pertain only to process vents from batch unit

operations. In the proposed rule, the EPA intended to include

flow rate and concentration cutoffs in this definition and in the

definitions of “process vents,” and “combination of process vents

that are Group 2." Therefore, the final rule includes these

cutoffs. However, the EPA did not feel that a revision was

necessary in §63.1428(h), in order to address the commenter’s

concern. 

2.4.13 Summing the Values

Comment: One commenter (IV-D-04) requested that the EPA

clarify what "summing the values" means in §63.1428(h)(1). This

section in the proposed rule describes how to determine the Group

status of "combinations" of continuous process vents by using

standard HON "TRE" calculation procedures, except for the

following difference: "summing the values in the individual

process vent streams." This could be interpreted either of two

ways: summing the stream data (such as concentrations and flow

rates), or summing the TRE index values. The commenter believed

the former was intended.

Response: This comment is no longer relevant since the EPA

decided to conduct Group determinations on an individual stream

basis for process vents from continuous unit operations (see

Section 2.4.4 of this document).
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2.4.14 Flares as a Reference Control Technology for Existing

and New Sources

Comment: Two commenters (IV-D-05 and IV-D-07) requested that

flares be allowed as a reference control technology for existing

and new source process vents. Commenter IV-D-05 stated that the

proposed rule (§63.1425(b)(2)(i)) does not specifically allow the

use of a flare as a control technology, as has been done in all

other standards impacting SOCMI type sources. However, according

to the commenter, the provisions of §63.1426(a) that require

owners or operators who use a flare to comply with the provisions

of §63.11(b), in conjunction with the exception from the

requirement to demonstrate the control efficiency, provide what

is essentially a reference control technology approach for

existing sources. The commenter also noted that in §63.1426(a),

in order to use only a flare to comply with the new source

epoxide standard for process vents in §63.1425(b)(1)(i), the

owner/operator must submit a request in accordance with §63.6(g). 

The commenter concluded that the issue seems to be whether the

destruction of epoxides in flares is significantly different from

that in other control devices, particularly in setting the new

source MACT floor level of control. 

Commenter IV-D-07 provided three attachments (test data and

general descriptions of flare use and destruction efficiency)

generated by the EPA and other key regulatory agencies, which is

at least equal in quality to the information available for new

sources in the MACT data base. Based on these data, the

commenter requested that the final rule adopt flares as a

reference control technology for both existing and new sources,

and the commenter suggested revisions to §63.1425(b)(1) and

(b)(2), accordingly. The commenter added that allowing flares to

be used as a reference control technology would result in a much

simpler compliance demonstration, with greatly simplified

monitoring, recordkeeping, and reporting burdens. In the event

that the EPA declines to adopt the flare as an alternative
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control technology for new sources, the commenter noted that the

language of §63.1426(e)(2)(i) would need to be changed to refer

to §63.1426(a), since §63.1426(a) allows the owner or operator to

attribute more than 98-percent control efficiency to a flare

(potentially), if a §63.6(g) request is made (where alternative

control devices are approved). Another commenter (IV-D-05)

claimed that new sources should not have to make complicated

demonstrations that compliance is achieved, and thus the

commenter recommended revising §63.1426(a) by deleting the second

sentence.

Response: The EPA agrees that flares should be listed as a

reference control technology in §63.1425(b)(2)(i), for existing

sources, for three reasons. The primary reason for adopting

flares as a reference control technology for existing sources is

because the EPA believes that flares, when operated properly,

effectively meet the emission limit. Additionally, a precedent

has been set in other rules to allow flares as a reference

control technology. Thirdly, this revision to the rule would

simplify the compliance demonstration and reduce the monitoring,

recordkeeping, and reporting requirements. Therefore, the EPA

has added this option to §63.1425(b)(2)(i). The EPA applied this

same rationale to Group 1 vents for making or modifying the

product and for process vents from catalyst extraction, and added

flares as a reference control technology for existing and new

sources with those emission points.

However, the EPA does not agree with the commenters

suggestion that flares should be listed as a reference control

technology for all new sources. Commenter IV-D-07 provided data

from three reports stating that a flare can achieve a destruction

efficiency of 99.5 percent for epoxides. These data do not

support equivalence with the 99.9 percent destruction efficiency

new source requirement for EO and PO.
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However, the EPA does agree with Commenter IV-D-07's request

that the language of §63.1426(e)(2)(i) be revised to allow for

the fact that flares may have been assigned a control efficiency

greater than 98 percent, if approval was previously granted by

the EPA in accordance with §63.6(g) of the General Provisions.

2.4.15 Use of Multiple Compliance Methods

Comment: One commenter (IV-D-07) requested that the EPA

establish that source owners/operators can mix and match

appropriate compliance methods for epoxide emissions. For

example, under §63.1425(b)(2), if a PMPU has more than one vent,

the commenter wanted to know if it is possible to control some

vents to 98-percent reduction efficiency by extended cookout and

to control others to <20 ppmv using a recovery, recapture, or

combustion device. The commenter stated that this allowance in

the final rule could be accomplished by rewording §63.1425(b)(2)

to require compliance with (i) and/or (ii), or (iii).

Response: First, the EPA would like to clarify that the

emission limit for an aggregated control efficiency allows for

some process vents within a PMPU to be controlled to different

levels, or some process vents to go uncontrolled, as long as the

overall control efficiency for emissions from all the process

vents within the PMPU equals 98 percent (for existing sources). 

So, for these instances, there is flexibility for controls within

a PMPU. 

Specifically though, the commenter is asking about complying

with different emission limitation formats for different process

vents within a PMPU. The EPA has considered the commenter's

request and has decided that the owner or operator can use either

the emission reduction format or the concentration cutoff within

the same PMPU. The EPA is not allowing the emission factor

format for this provision of multiple emission reduction formats,
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because the emission factor format sets a maximum allowable

amount of emissions for process vents in the PMPU. 

2.4.16 Uses and Emission Point Locations of Nonepoxides

Comment: One commenter (IV-D-07) stated that, in addition

to the examples of uses that the EPA included in the preamble

(such as use of a nonepoxide HAP as an initiator, catalyst, or a

reaction solvent), nonepoxide HAP may be used as a viscosity

adjuster in or downstream of the reactor, or to provide special

properties to the final product. The commenter asserted that,

contrary to the EPA's apparent understanding that all process

vents are manifolded or otherwise connected (Supplementary

Information Document (SID), page 20 of April 25, 1997 letter on

estimated impacts), these vents may and do emit at different

points in the process.

Response: This comment presented the idea that nonepoxide

HAP process vent emission points exist downstream from the

reactor, and that these emission points are probably not

manifolded to the process vents from the reactor. The owner or

operator is required to perform a group determination on these

emission points. As discussed previously, the EPA has decided

that group determinations for process vents from continuous unit

operations will be made on an individual vent basis. Therefore,

this should not cause a problem for group determinations for

process vents from continuous unit operations downstream of the

reactor. 

For process vent emissions from batch unit operations, the

EPA is maintaining the requirement that group determinations be

made on an aggregated vent basis. As stated earlier, even though

the group determination is made on an aggregated vent basis, the

facility is not required to physically combine the downstream

process vent streams to the reactor vent streams for purposes of

emissions control. 
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2.4.17 Possibility of Dual Controls For Nonepoxide HAPs from

Making or Modifying the Product

Comment: One commenter (IV-D-07) referred to the proposal

preamble statement that a process vent from which nonepoxide HAP

are emitted may also be subject to the epoxide emission reduction

requirements, and noted that this is only true in the event that

such a vent originates at a point in the process where it

contains epoxide and requires control. The commenter also noted

that the EPA’s assertion in the proposal preamble (that if a

combustion, recovery, or recapture device is used to reduce

epoxide emissions from the vent, then that same device would also

reduce the emissions of the nonepoxide HAP) is only correct if

the vents are, or reasonably can be, combined, and if the device

is effective for the nonepoxide HAP in question. For instance,

the commenter stated that scrubbers may not be effective for some

nonepoxide HAP materials used to make or modify the product. The

commenter continued by stating that if extended cookout is the

control technique utilized by the facility to reduce epoxide

emissions, then the nonepoxide HAP emissions would not be

affected (unless they were initiators or possibly catalysts) and

would need to be addressed separately (indicating a possible

requirement for dual controls).

The commenter offered three options for alternate approaches

to those suggested by the EPA for addressing process vent

emissions of nonepoxide HAP from making or modifying the product,

to resolve the possible dual control requirement problem:

Option 1: Require a group determination for only nonepoxide

HAP emissions that are not controlled along with epoxide

emissions. The commenter believes that this option offers a

workable approach, so long as the triggers selected and emission

reductions required are consistent with section 112 requirements.

Option 2: Require all HAP emissions (epoxide and

nonepoxide) from making or modifying the product to be reduced by

the amount specified in the proposed rule for epoxide emissions. 
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The commenter did not encourage the EPA to choose this option. 

The commenter claimed that in order to justify this approach, the

EPA must consider that the floor for nonepoxide emission

reductions is much less than the floor for epoxide emission

reductions, and then must justify an emission reduction

requirement above the MACT floor. The commenter believed that

this demonstration would be very difficult for the EPA to make,

since not all controls in the floor are effective in reducing

nonepoxide HAP emissions, and since floors of zero and 39-percent

reduction were found for existing and new sources.

Option 3: The commenter mentioned the option of eliminating

the group determination provisions for nonepoxide HAP emitting

and requiring a specified percent emission reduction from all

vents above a "de minimis" nonepoxide HAP level. The commenter

concluded that the "de minimis" option, as proposed, is not

defined well enough for full comment. However, the commenter

noted that the standard for Polymers and Resins I, subpart U,

provides precedent for a de minimis level threshold of 225

kg/yr/vent emissions as part of the definition for a batch frontend process vent.

The commenter suggested, as an alternate option, that the

EPA focus the final rule on epoxide and catalyst recovery

emissions only, because nonepoxide HAP process emissions from

making or modifying the product are insignificant, even if

uncontrolled.

Response: The EPA considered the commenter’s points and the

options suggested by the commenter. The final rule requires that

the group determination for nonepoxide HAP emissions be made

after the stream has been controlled for the epoxide emissions

(commenter’s option 1). The EPA believes that this approach

addresses the situation regarding the possibility of dual

control. If the epoxide control device also reduces nonepoxide

emissions, then that control would impact whether the vent (or
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group of batch vents) is Group 1. Therefore, control of

nonepoxide emissions along with the epoxides will impact whether

controls are required at all. If the vent (or group of vents)

still has sufficient nonepoxide organic HAP emissions after the

epoxide control device to satisfy the Group 1 criteria, the EPA

does not believe it is unreasonable to require an additional

control device to achieve the specified percent reduction of the

nonepoxide emissions.

Therefore, using the example given by the commenter (of a

scrubber controlling epoxide emissions), the TRE index or the

Batch ACT equation would be applied to the stream at the outlet

of the scrubber. Likewise, if ECO is used as the control option,

the Batch ACT equations (assuming that ECO is applicable for

batch unit operations only) would be applied to the stream after

the ECO is completed.

2.4.18 Clarification of "Schedule for Compliance"

Comment: One commenter (IV-D-05) requested that the EPA

confirm, perhaps in the preamble, that a "schedule for

compliance" (as used in §63.1425(f)(7)(i)(B) and (f)(7)(ii)(B),

§63.1430(i)(2) and elsewhere in the rule) is not the same thing

as a "compliance schedule" in the General Provisions. Two

commenters (IV-D-04, IV-D-05) requested that the EPA change the

term "compliance schedule" in §63.1439(e)(6)(iii)(D)(1), and in

various other locations in the rule, to say "schedule for

compliance." This will avoid use of a term (compliance schedule)

from subpart A, which is under litigation.

Response: Because the Notification of Compliance Status is

the report in which compliance (or non-compliance) is ultimately

documented, the EPA decided that it was not necessary for owners

or operators of affected sources to submit a compliance schedule,

or a “schedule for compliance”. For this reason, the terms

"compliance schedule" and “schedule for compliance” have been
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removed throughout the final rule (including in §63.1423,

§63.1425(f)(7)(i)(B), §63.1425(f)(7)(ii)(B),

§63.1425(f)(7)(iii)(B), §63.1425(f)(7)(iv)(B), §63.1430(i)(2),

§63.1439(e)(6)(iii)(D)(1), §63.1439(e)(6)(iii)(D)(2), and the

title of §63.1422), and all requirements to report information in

a "compliance schedule" or “schedule for compliance” have been

removed. In particular, the owner or operator is no longer

required to submit a schedule for compliance with the applicable

provisions after process changes. However, please note that this

final rule does not override other regulations that might require

compliance schedules (e.g., Title V requirements, NSPS, or RACT

standards).

2.4.19 THE PMPU Exemption from Reporting

Comment: One commenter (IV-D-05) claimed that

§63.1425(f)(7)(ii),(iii) and (iv) under the "Requirements for

process vents at PMPUs that produce polyether polyol products

using tetrahydrofuran" should not require the submission of a

report if there is some other basis for exemption, such as a flow

rate below 0.005 scmm for paragraph (ii) or (iv), or a HAP

concentration less than 50 ppmv for paragraph (iii). Therefore,

the commenter recommended revising the text as follows:

"(ii) Whenever a process change, as defined in

§63.115(e) of subpart G, is made that causes a Group 2

process vent with a TRE greater than 4.0 to become a Group 2

process vent with a TRE less than 4.0, the owner or operator

shall submit a report within 180 days after the process

change is made or the information regarding the process

change is known to the owner or operator unless the flow

rate is less than 0.005 scmm. This report may be included

in the next Periodic Report. The following information

shall be submitted...”

“(iii) Whenever a process change, as defined in

§63.115(e) of subpart G, is made that causes a Group 2

process vent with a flow rate less than 0.005 standard cubic

meter per minute (scmm) to become a Group 2 process vent

with a flow rate of 0.005 scmm or greater, and a TRE index

value less than or equal to 4.0, the owner or operator shall

submit a report within 180 days after the process change is
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made or the information regarding the process change is

known to the owner or operator unless the organic HAP

concentration is less than 50 ppmv. This report may be

included in the next Periodic Report. The following

information shall be submitted...”

“(iv) Whenever a process change, as defined in

§63.115(e) of subpart G, is made that causes a Group 2

process vent with an organic HAP concentration less than 50

parts per million by volume (ppmv) to become a Group 2

process vent with an organic HAP concentration of 50 ppmv or

greater and a TRE index value less than 4.0, the owner or

operator shall submit a report within 180 days after the

process change is made or the information regarding the

process change is known to the owner or operator unless the

flow rate is less than 0.005 scmm. This report may be

included in the next Periodic Report. The following

information shall be submitted...”

Response: The EPA agrees with the commenter, and the

changes suggested have been incorporated into the final rule. 

The EPA also incorporated these changes into paragraphs

§63.1430(j)(1) through (3) of the final rule, which contain

similar reporting provisions for Group 2 continuous process vents

associated with making or modifying the product.

2.4.20 Clarification to Condenser Identity

Comment: One commenter (IV-D-04) requested that the EPA

clarify whether all condensers are equal. Section

63.1426(c)(1)(i)(A)(1) provides that the inlet sampling site must

be at the exit from the continuous unit operation "before any

recovery devices." The commenter asked about reflux condensers. 

Reflux condensers fit the definition of "recovery device," but

they are considered to be part of the process unit (either the

reactor or distillation unit). The commenter questioned whether

the inlet sampling site should be before, or after, reflux

condensers. Another commenter (IV-D-05) claimed that the word

"at" seems to allow only one location, while the word "before"

seems to allow more than one location. For clarity, the

commenter recommended that the phrases in
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§63.1426(c)(1)(i)(A)(1), (c)(1)(i)(B), (d)(2), and (d)(3)(i)(A)

be changed to read "at or after the exit from the ... before any

recovery device."

Response: The reflux condenser is considered to be part of

the unit operation to which it belongs (be that a condenser or

reactor), and is not a recovery device. To clarify this in the

final rule, the EPA has redefined "recovery device" as follows:

"Recovery device means an individual unit of equipment

capable of and normally used for the purpose of recovering

chemicals for fuel value (i.e., net positive heating value),

use, reuse, or for sale for fuel value, use, or reuse. 

Reflux condensers are not recovery devices. Examples of

equipment that may be recovery devices include absorbers,

carbon adsorbers, condensers (except reflux condensers,

because they are part of the reactor unit operation), oilwater separators or organic-water separators, or organic

removal devices such as decanters, strippers, or thin film

evaporation units. When this subpart requires compliance

with For the purposes of the monitoring, recordkeeping, or

recording reporting requirements of this subpart, recapture

devices are considered to be recovery devices."

As stated in the definition of recovery device, a reflux

condenser is not a recovery device. Therefore, the inlet

sampling site is after the reflux condenser, and before the

control or recovery device. The EPA agrees with Commenter IV-D05's suggestion to use the word "after" in the context of "after

the exit from the...before any recovery device." However, the

EPA feels having both "at" and "after" is not necessary. 

Therefore, the EPA revised the appropriate phrases in

§63.1426(c)(1)(i)(A)(1), (c)(1)(i)(B)(1), (d)(2), and (d)(3)(i)

in the final rule, accordingly.

2.4.21 Small Combustion Device Performance Testing

Comment: One commenter (IV-D-05) noted that

§§63.1426(c)(1)(i)(C), (C)(4)(iv), and §63.1430(b)(2)(iv)

describe how to collect samples during performance tests on

boilers or process heaters with a design capacity of less than 44
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megawatts. The commenter recommended revising the text as

follows:

"If a process vent stream is introduced with the combustion

air or as a secondary fuel into a boiler or process heater with a

design capacity less than 44 megawatts and is not otherwise

exempt from performance testing under this subpart, selection of

the location of the inlet sampling sites shall ensure the

measurement of total organic HAP or TOC (minus methane and

ethane) concentrations in all process vent streams and primary

and secondary fuels introduced into the boiler or process

heater."

Response: The EPA does not believe that the language

suggested by the commenter adds clarity to the exemption, since a

control device may be exempt based on its design capacity or for

other reasons. Further, the recommended addition has not been

added to the final rule because a process vent is not subject to

performance testing (only a control device can be subject to or

exempt from performance testing). For these reasons, the EPA did

not incorporate the additional language requested by the

commenter.

2.4.22 Concentration Compliance 

Comment: One commenter (IV-D-05) recommended removing “in

lb." as the unit of measure from §63.1426(c)(3)(i)(B)(1) and (2)

and §63.1426(c)(3)(i)(C). The commenter stated that these

provisions should use the percentage without needlessly

specifying the unit of measure. In addition, the commenter

claimed that the first sentence in §63.1426(c)(3)(i)(B)(1) and

(2) were incomplete. Therefore, the commenter requested revising

the text. 

Response: The Agency agrees that the phrase "in lb." was

not necessary for a percentage, and has deleted it from
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§63.1426(c)(3)(i)(B)(1). However, this same change was not made

in §63.1426(c)(3)(i)(B)(2) or in §63.1426(c)(3)(i)(C), because

there is no percent in these paragraphs and the "lb/hr" is

needed. The EPA agrees with the commenter’s claim that the first

sentence in §63.1426(c)(3)(i)(B)(1) and (2) were incomplete. 

This grammatical error was corrected when these sections were

replaced with the new “worst case” language. 

2.4.23 "Organic HAP" versus "HAP of Concern"

Comment: One commenter (IV-D-04) supported the use of the

phrase "HAP of concern" in §63.1426. However, there are several

places in that section where the EPA mentions "organic HAP"

without saying "of the HAP of concern." This could be

misunderstood to mean that every organic HAP species must be

considered, whether or not the species is relevant to the

regulatory provisions with which industry is demonstrating

compliance. Therefore, the commenter requested that the EPA use

the phrase "of the HAP of concern" consistently when "organic

HAP" is mentioned in §63.1426, unless there is a specific reason

not to.

Response: The EPA appreciates the commenter’s support of the

phrase “HAP of concern,” and has made an effort to be sure that

this phrase was used in the final rule, where necessary. 

However, in many instances in §63.1426, it was not appropriate to

follow the term “organic HAP” with the phrase “of the HAP of

concern,” because the term “organic HAP” is used as a modifier

for another term (such as “percent reduction efficiency”), so the

EPA disagreed with the commenter about using the phrase “organic

HAP of the HAP of concern” universally throughout §63.1426. One

instance in which the EPA made a change in keeping with the

commenter’s suggestion, however, was in §63.1426(c)(3)(i)(A),

where it was in fact appropriate to follow the term “HAP” with
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the phrase “of the HAP of concern,” because clarification was

necessary in that paragraph.

2.4.24 Rename "Product" as "Reactor Liquid"

Comment: One commenter (IV-D-05) stated that

§63.1427(h)(1)(iii) and (h)(2)(iii) refer only to direct

measurement of epoxide concentration in the reactor liquid at the

end of ECO. Changing "reactor liquid" to "product" would allow a

producer to drop the product from the reactor and sample it in a

tank rather than forcing them to sample it in the reactor itself. 

This will improve reactor utilization, allowing prompt emptying

of the batch (so another may be started), and will not affect the

accuracy of the epoxide sample, since the reaction essentially

stops once the product is cooled. Therefore, the commenter

recommended revising these paragraphs to use the term "product"

in place of the term "reactor liquid."

Response: The commenters want to sample the mixture as, or

after it leaves the reactor. The EPA has added language to the

final rule [in §63.1427(h)(1)(iii) and (h)(2)(iii)] explaining

when/where the sample may be taken. The EPA considers this to be

a more appropriate solution to the comment than using the term

"product" instead of the term "reactor liquid," since "product"

was already defined in the proposed rule. Further, the EPA has

added the definition of reactor liquid to the final rule and

defined it as follows:

"Reactor liquid means the compound or material made in the

reactor, even though the substance may be transferred to

another vessel. This material may require further

modifications before becoming a final product, in which case

the reactor liquid is classified as an "intermediate." This

material may be complete at this stage, in which case the

reactor liquid is classified as a "product."

2.4.25 §63.1425(e)(1)(i)
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Comment: For clarity and to avoid unnecessary repetition,

one commenter (IV-D-05) recommended revising the text in

§63.1425(e)(1)(i), as follows:

"If an owner or operator chooses to comply with the control

efficiency provisions in paragraph (b)(1)(i) or (b)(2)(i) of this

section, the owner or operator shall comply with the provisions

of paragraph (b)(1)(i) or (b)(2)(i) of this section by

determining determine the epoxide emissions before and after

control."

Response: The EPA agrees with the commenter that

§63.1425(e)(1)(i) needs more clarity. The proposed

§63.1425(e)(1)(i) could have been interpreted to mean that

performing the determination of the controlled and uncontrolled

emissions would be equivalent to complying with §63.1425(b)(1)(i)

or (b)(2)(i), and this would have been an incorrect

interpretation. Further, the EPA agrees that, as proposed,

§63.1425(e) was redundant with many of the requirements in 

§63.1425(b) through (d). Therefore, the EPA has “reserved”

§63.1425(e) in the final rule, and the appropriate process vent

control requirements are now contained in §63.1425(b) through (d)

only, as appropriate. 

2.5 EXTENDED COOKOUT AS A CONTROL OPTION

2.5.1 In Support of the Inclusion of ECO

Comment: Five commenters (IV-D-03, IV-D-04, IV-D-05, IV-D07, IV-D-10) fully supported the proposed rule’s inclusion of the

concept of "extended cookout (ECO)," as a pollution prevention

technique. One commenter (IV-D-10) noted that their company had

worked closely with the EPA to define the calculation procedures

to demonstrate that equivalent epoxide emission reductions that

can be obtained using ECO compared to conventional control

technology.

Response: The Agency appreciates the commenter’s support. 

2.5.2 ECO Compliance Demonstration
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Comment: One commenter (IV-D-04) noted that the proposed

rule would require ECO to reduce emissions by 98 percent;

however, the rule does not seem to require the owner or operator

to demonstrate that a 98-percent emission reduction (or any other

level of emission reduction) is actually being achieved. In a

follow-up telephone conference with the commenter (Docket Item

IV-E-1), the commenter explained that his first impression of

this requirement was that it was not objective enough, in

comparison with other rules. However, when the commenter

reviewed the section again, he realized that the rule provided

adequate steps for demonstrating compliance with the rule. 

Further, commenter IV-G-02 submitted a late comment after

reading Commenter IV-D-04's comment, in which Commenter IV-G-02

disagreed with the above comment and stated that a demonstration

of the percentage emission reduction achieved by ECO is

specifically required in §63.1427(a). 

Response: The EPA agrees with Commenter IV-G-02's late

comment, which stated that a demonstration of the percentage

emission reduction achieved by ECO is specifically required in

§63.1427(a). However, the word "demonstrate" is not specifically

stated in §63.1427(a); therefore, the EPA decided to revise the

language in the final rule as follows:

“(a) Owners or operators of affected sources that produce

polyether polyol products using epoxides, and that are using

ECO extended cookout (ECO) as a control technique to reduce

epoxide emissions in order to comply with percent emission

reduction requirements in §63.1425(b)(1)(i) or (b)(2)(ii)

shall demonstrate that the specified percent emission

reduction is achieved by determining determine the batch

cycle percent epoxide emission reduction for each product

class in accordance with the provisions of paragraphs (b)

through (g) of this section....” 

2.5.3 Flexibility of the Determination of a Site-specific

Onset of ECO
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Comment: Three commenters (IV-D-04, IV-D-05 and IV-D-07)

supported defining the onset of ECO as the point in time when the

combined unreacted epoxide concentration in the reactor liquid is

equal to 25 percent of the concentration of epoxides at the end

of the epoxide feed. However, there was disagreement over

whether site-specific ECO onset determination should be allowed

in the final rule.

Commenter IV-D-05 supported the proposed provisions that

allowed individual producers the opportunity to provide their own

economic justification for the onset of ECO, and noted that the

mechanism for a request for a site-specific ECO onset was the

Precompliance Report, which is required to be submitted one year

before the compliance date. However, the commenter stated that

an owner or operator should be allowed the opportunity to change

the onset point. They recommended that the opportunity to

establish a different ECO onset point should not be limited to

the precompliance stage.

Commenter IV-D-07 added that an individual producer should

have the ability to prove a different starting point based on

that producer’s economics. The commenter noted that the proposed

default definition of the onset of ECO was based on average

conditions, and that a producer may well have very different

economics from those presented in the model calculations. The

commenter maintained that the ability to request an alternative

definition is appropriate and necessary. The commenter also

added that the mechanism provided in §63.1427(c)(3) for an

alternate determination, and the reference to Item II-B-7 of the

docket contained in the proposal preamble, are appropriate. 

However, this commenter expressed concern that the basis

referenced in the proposal preamble will be lost over time, and

suggested that this reference be included in the actual rule at

§63.1427(c), or, at the very least, that the reference be

included in the preamble to the final rule.
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In contrast, Commenter IV-D-04 was concerned that there was

too much flexibility in the requirements describing how to

establish the onset of ECO on a site-specific basis. The

commenter cautioned that selecting the onset based on the

economics of polyether polyol production has the potential for

being misused. The commenter explained in the comment that the

operator may select an earlier onset of ECO, making it easy to

demonstrate a 98-percent emission reduction and to justify this

ECO onset on the basis of economic factors. The commenter

cautioned that economics can be very subjective. The commenter

also cautioned that, in contrast to demonstrations of compliance

with other control devices, the determination of the onset of ECO

does not have standardized procedures. The commenter did state

that they had confidence in the default value for the onset of

ECO.

Further, the commenter pointed out that requiring an

emission reduction of 98 percent for ECO might still allow

emissions to exceed the applicable emission factors described in

§63.1425(b)(1) or (b)(2). As assurance that the ECO provisions

are used appropriately, the commenter requested that EPA require

that owners and operators using ECO with an onset other than the

default onset listed in the rule comply with the applicable

emission factor in §63.1425(b)(1) or (b)(2) and not have the

option of using the 98 percent emission reduction for

demonstrating compliance with the rule. According to the

commenter, this will serve two purposes: (1) it will assure that

ECO achieves substantial "real" emission reductions; and (2) it

will provide for a compliance demonstration for ECO.

Commenter IV-G-02 submitted comments in response to the

issues raised by Commenter IV-D-04. This commenter pointed out

that the economic evaluation which was accepted by the EPA and

that formed the basis for the default ECO onset is very simple. 

Provisions for investment in the unit or many other significant

costs that should be considered for true profitability were not
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used in the analysis. The evaluation was simple and conservative

to avoid any significant debate over cost issues that producers

would be reluctant to divulge for competitive reasons or that

would be difficult for regulators to verify from outside sources. 

The commenter believed that not allowing the site-specific ECO

onset would provide a disincentive to producers who elect to use

ECO as a control technology.

In response to Commenter IV-D-04's concern over sitespecific onset, Commenter IV-G-02 stated that establishing a

site-specific onset is not arbitrarily selected by the owner or

operator. The owner or operator must submit a request for an

alternative ECO onset, and this alternative must be approved by

the Administrator. The commenter points out that this is a

typical EPA “alternative standard-getting” process used in many

Regulatory settings. The commenter also points out that the data

required to be provided by the owner or operator for a sitespecific alternative ECO onset request are readily available.

In response to Commenter IV-D-04's request that the EPA

require ECO to achieve the applicable emission factor, Commenter

IV-G-02 stated that there is not need to “safeguard” ECO

reductions by requiring compliance with an emission factor. This

would remove one of the compliance options for these sources and

provide a potential competitive advantage for sources using an

add-on control technique. The commenter stressed that sources

that use ECO should not have to pay a penalty by complying with a

different standard that those who have elected to use

manufacturing methods which emit greater quantities of epoxide to

an add-on control device.

Response: First, the EPA agrees with Commenter IV-G-02 that

sources using ECO should not be restricted to achieving

compliance with the applicable emission factor. In the final

rule, owners or operators using ECO may comply by using either
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the applicable percent reduction or the applicable emission

factor.

However, the EPA also recognizes the concern raised by

commenter IV-D-04 that changing the ECO onset, and thus the point

for determining the uncontrolled emissions, could significantly

impact the percent reduction achieved by the ECO. The EPA also

shares the concern that economics can be very subjective,

although the EPA agrees with the Commenter IV-G-02 that the

proposed criteria for a site-specific request would not allow the

arbitrary selection of an alternative ECO onset.

However, the EPA disagrees with the statement by Commenter

IV-G-02 that the approval of a site-specific onset by the

Administrator would represent a “typical” EPA alternative process

used in many regulatory settings. The Agency does routinely

evaluate alternative control technologies and their equivalency

to the control technologies or levels specified in regulations. 

Typical evaluations may involve economics, with respect to the

cost of the technology in relation to the corresponding emission

reduction (i.e., the cost effectiveness). However, these

decisions are made in assessing alternative requirements for

categories and/or subcategories of sources, and are not made for

individual sources. In reassessing the appropriateness of a

site-specific onset option, the EPA concluded that the subjective

nature of the option could result in different levels of control

between facilities in the same subcategory. That result would be

inconsistent with the concept of MACT. Therefore, in the final

rule, the EPA has removed the option of requesting and

establishing a site-specific ECO onset point.

 

2.5.4 ECO Requirements for Monitoring

Comment: One commenter (IV-D-04) requested that the EPA

specify in the final rule appropriate compliance demonstration

requirements, monitoring requirements, bypass requirements,

parameter level requirements, etc., for emission control devices
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that are used to supplement ECO. According to the commenter,

these requirements appear to be missing in the proposed rule. 

The commenter also suggested that the EPA review the entire rule

to insure that all requirements apply appropriately to all

control devices, regardless of whether those devices are used

with (or without) ECO.

Commenter (IV-G-02) provided comments after the end of the

comment period, in response to Commenter IV-D-04's input. 

Commenter IV-G-02 did not see any "gap" in the requirements for

ECO demonstrations, monitoring, etc. This commenter interpreted

§63.1427 as providing for compliance demonstrations, monitoring,

etc. for the ECO portion of the compliance alternative, and

believed that §63.1427 clearly refers the source owner or

operator to other portions of the rule for demonstrations and

monitoring for using other control devices. 

Response: The Agency called Commenter IV-D-04 on April 23,

1998 (See Docket Item IV-E-2). The commenter explained that

compliance demonstration requirements, monitoring requirements,

bypass requirements, and parameter level requirements are given

for ECO, but not for those emission control devices that are used

to supplement ECO. The final rule includes compliance

demonstration requirements, monitoring requirements, bypass

requirements, and parameter level requirements for those emission

control devices that are used to supplement ECO. The following

language was added to §63.1427(a):

“If additional control devices are used to further reduce

the HAP emissions from a process vent already controlled by

ECO, then the owner or operator shall also comply with the

testing, monitoring, recordkeeping, and reporting

requirements associated with the additional control device,

as specified in §§63.1426, 63.1429, and 63.1430,

respectively.”
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2.5.5 Accuracy "Buffer" for ECO Emissions Calculations

Comment: One commenter (IV-D-07) recommended that guidance

on an acceptable accuracy range be added to the provisions in

§63.1427(a)(2), which requires measurement of the percent

reduction for each product to verify the accuracy of the

estimation method selected, in order to resolve conflicts when

measurements and calculations are not exactly equal. The

commenter suggested that kinetic models are likely to be accurate

to within +/- 10 percent, for typical situations. The commenter

noted that this request is valid only if engineering calculations

are not allowed as requested in a previous comment (Section

2.12.8) or if a compliance test is conducted for ECO. The

commenter recommended that §63.1427(a)(2) be modified as follows:

"The owner or operator may determine the batch cycle

percent epoxide reduction by directly measuring the

concentration of the unreacted epoxide, or by using

process knowledge, reaction kinetics, and engineering

knowledge. If the owner or operator elects to use any

methods other than direct measurement, the percent

reduction must be determined by direct measurement for

one product for each PMPU to verify the accuracy of the

estimation method selected. The alternate method of

estimating the concentration of unreacted epoxide is

acceptable if it is within +/- 25 percent of the result

of direct measurement."

 

Response: The Agency agrees with the concept of needing an

"accuracy buffer," but, does not believe that 25 percent is an

appropriate value. The EPA believes that 10 percent is a more

reasonable buffer to allow use of the calculations without

adjustment. For situations where the difference between the

calculation and the measurement is between 10 and 25 percent, the

calculated values may be used, but need to be adjusted. The EPA

revised the text suggested by the commenter and incorporated it

into §63.1427(a)(2) in the final rule, as follows: 

(2) The owner or operator may determine the batch

cycle percent epoxide emission reduction by directly

measuring the concentration of the unreacted epoxide, or by

using process knowledge, reaction kinetics, and engineering
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knowledge, in accordance with paragraph (a)(2)(i) of this

section. 

(i) If the owner or operator elects to use any method

other than direct measurement, the percent reduction must

epoxide concentration shall be determined by direct

measurement for one product for each PMPU to verify the

accuracy of the estimation method selected from each product

class and compared with the epoxide concentration determined

using the selected estimation method, with the exception

noted in paragraph (a)(2)(ii) of this section. If the

difference between the directly determined epoxide

concentration and the calculated epoxide concentration is

less than 25 percent, then the selected estimation method

will be considered to be an acceptable alternative to direct

measurement for that class. 

(ii) If uncontrolled epoxide emissions prior to the

end of the ECO are less than 10 tons per year (9.1 megagrams

per year), the owner or operator is not required to perform

the direct measurement required in paragraph (a)(2)(i) of

this section. Uncontrolled epoxide emissions prior to the

end of the ECO shall be determined by the procedures in

paragraph (d)(1) of this section.

The proposed rule contained an error in the second sentence

in §63.1427(a)(2). That sentence should have read; "If the owner

or operator elects to use any methods other than direct

measurement for one product for each PMPU product class to verify

the accuracy of the estimation method selected." The EPA

intended that the comparison of the engineering calculations to

the direct measurement be conducted on a product class basis,

since each product class behaves differently.

2.5.6 Clarification of the Definition of "Emissions" in ECO

Destruction Efficiency Calculation 

Comment: One commenter (IV-D-04) cited three locations in

§63.1427(c) that use the word "emissions," but the intended

meaning of the word is unclear: (1) "the uncontrolled emissions

for the batch cycle;" (2) "the epoxide emissions prior to the

onset of the ECO;" and (3) "the epoxide emissions at the onset of

the ECO.” The commenter requested clarification of the word

"emissions" in these cases. In the first case, the commenter was
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unsure whether “emissions” meant the emissions that would occur

if there were no ECO, or emissions that remain after ECO and are

either sent to a control device, or released (without "control"

after ECO) to the air. In the second and third instances, the

commenter was unsure about whether “emissions” meant actual

emissions that really occur, or emissions that would have

occurred if there were no ECO. Commenter IV-D-05 suggested

replacing the language in the second case with the following

language: "...calculate the uncontrolled epoxide

emissions...calculating the epoxide emissions, if any, prior to

the onset of the ECO."

As a rebuttal to Commenter IV-D-04's comment, another

Commenter (IV-G-02) stated that Equation 7 in §63.1427(c)(1)

describes how to calculate "the uncontrolled emissions for the

batch cycle." These are the calculated epoxide emissions that

would occur in the absence of ECO if the reactor were opened at

the time that ECO commenced plus any epoxide emissions that

actually occur prior to that time.

Commenter (IV-G-02) also stated that the "epoxide emissions

prior to the onset of the ECO" are those emissions that actually

occur from process vents (for example, those that occur as a

result of initial reactor charge). The commenter added that the

method for calculating these emissions is specified in

§63.1426(d) in conjunction with the definition of “Epoxide” in

§63.1423(b).

Commenter (IV-G-02) noted that the "epoxide emissions at the

onset of the ECO" are described in §63.1427(c) and are calculated

according to §63.1427(b). These are the emissions that would

occur from the reactor contents if there were no ECO. They are

calculated as 25 percent of the reactor epoxide contents unless

the owner/operator justifies an alternate starting point. 

Commenter (IV-G-02) ended by saying that the relation between

uncontrolled epoxide emissions and the epoxide emissions at the

onset of ECO is described in Equation 7.
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Response: The Agency defines ECO as a control option;

therefore, uncontrolled emissions are emissions that would have

occurred had there not been an ECO. This definition is in accord

with the interpretation offered by Commenter IV-G-02. Further,

the "epoxide emissions at the onset of the ECO" that the Agency

is referring to are any actual emissions that occur before the

beginning of the ECO, which is again in agreement with Commenter

IV-G-02's interpretation. Therefore, no changes have been made

to the final rule as a result of Commenter IV-D-07's concern.

2.5.7 First Order for Epoxide Reactions

Comment: One commenter (IV-D-07) responded to the EPA’s

request for documentation to support or refute the first order

reaction rate equation used in the ECO calculation (62 FR 46814). 

The commenter has developed proprietary reaction models based on

extensive laboratory and commercial plant operation data, but

this information is not public information. However, they

included a copy of a paper on reaction kinetics by K. Nagase and

Y. Sakaguchi, which was presented at the 12th annual meeting of

the Japanese Chemical Society, April 1959, which the commenter

considered to be a good source of information. The commenter

noted that their proprietary models do use a first order reaction

rate with respect to epoxide concentration to describe the

reaction.

Response: The Agency appreciates this input and has

retained the assumption that the polyol production reaction is

first order with respect to the epoxide.

2.5.8 Update of Product Class List

Comment: One commenter (IV-D-04) stated that in situations

where a change in operating conditions causes a product to move

from one product class to another, §63.1427(l)(3)(i)(A) requires

industry to "update the list of products for the product class,"
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and then §63.1427(l)(3)(i)(B) requires submission of a report

updating the list for "the product class." The commenter

requested that these sections be revised so that the owner or

operator knows which updated list of products within a product

class to update: the class that this product has just left, or

the class that this product has just entered, or both lists.

Commenter IV-D-05 requested the following change to the text

in §63.1427(l)(3)(i)(B), as follows:

"Within 180 days of the change in operating conditions

for the polyether polyol product, the owner or operator

shall submit a report updating the product list originally

submitted for the product class. This information may be

submitted along with the next Periodic Report."

Response: The EPA agrees that the proposed rule did not

make it clear which product lists need to be updated when

operating conditions cause a product to move from one product

class to another. The EPA has revised what was

§63.1427(l)(3)(i)(B), which is §63.1427(m)(3)(i)(B) in the final

rule, to read as follows: 

"Within 180 days after of the change in operating

conditions for the polyether polyol product, the owner or

operator shall submit a report updating the product lists

originally previously submitted for the product class. This

information may be submitted along with the next Periodic

Report.” 

2.5.9 Product Class Definition 

Comment: One commenter (IV-D-07) requested the following

technical correction in proposed §63.1427(i)(1)(i)(E):

"The group product classification should depend on EO/PO

ratio at the end of the batch, not the ratio during the batch." 

Further, Commenter IV-D-05 commented that he understood that

the concentration in §63.1427(i)(1)(iv) is to be determined at

the "onset of the ECO" rather than at the "end of the onset of

ECO." Therefore, the commenter recommended revising the text

accordingly.
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Response: In the proposed rule, §63.1427(i)(1)(i)(E) did not

specify when in the batch the EO/PO ratio should be determined. 

The EPA believes that the time in the batch at which the EO/PO

ratio is to be determined should be specified, and proposed

§63.1427(i)(1)(i)(E) (§63.1427(j)(1)(i)(E) in the final rule) has

been revised to specify that this ratio shall be determined at

the end of the epoxide feed, because, according to some

commenters (docket item no. IV-G-10), the EO/PO ratio changes

during a batch, but has leveled out by the time that extended

cookout begins. Further, §63.1427(j)(1)(iv) in the final rule

has been revised as requested by commenter IV-D-05.

2.5.10 Pressure Measurements

Comment: One commenter (IV-D-05) referred to §63.1427(g),

which requires the calibration of pressure measurement devices

"in accordance with manufacturer’s recommendations." The

commenter claimed that this has the unintended effect of

transferring the setting of enforceable regulatory standards to

third parties. In addition, some manufacturer’s recommendations

may be inappropriate for purposes of this rule. Therefore, the

commenter recommended revising the text using language adopted

into the amended HON, as did §63.1429(a) at proposal. 

Response: Since the Agency has determined that the language

used in the HON and §63.1430(a) is also appropriate in

§63.1427(g), the final rule has incorporated similar language

into §63.1427(g), as follows: 

"(g) Determination of pressure. The owner or operator

shall determine the total pressure of the system using

standard pressure measurement devices calibrated in

accordance with according to the manufacturer's

specifications or other written procedures that provide

adequate assurance that the equipment would reasonably be

expected to monitor accurately."

2.5.11 ECO Recordkeeping
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Comment: One commenter (IV-D-05) asserted that in

§63.1427(i)(1)(i)(C) it makes no sense to include the number of

-OH groups in the catalyst feed. The metal ion is the active

species for these reactions, not the base. In addition, some of

these reactions may be self catalyzed or acid catalyzed, and

there will be no -OH groups in these systems. The appropriate

measure should be the number of -OH groups (or, better, the

number of reactive sites) in the starting material that is being

reacted with the epoxide. Therefore, the commenter recommended

revising the text, as follows:

"(i) Operating conditions of the product class, including

 (A) Pressure decline decay curve

 (B) Minimum reaction temperature

 (C) Number of -OH groups in the catalyst feed raw material

 (D) Minimum catalyst concentration

 (E) The EO/PO ratio

 (F) Reaction conditions, including the size of the reactor 

 or batch"

Response: The EPA agrees that the term “raw material” is a

better description of where the reactive hydrogens are than the

phrase "catalyst feed," and has made the suggested change to what

was §63.1427(i)(1)(i)(C), and is §63.1427(j)(1)(i)(C) in the

final rule. Further, in §63.1427(j)(1)(i)(C), the EPA has

replaced the term "number of -OH groups in the catalyst feed"

with the term “number of reactive hydrogens in the raw material,”

because the phrase "reactive hydrogens" is consistent with the

terminology used in the definition of polyether polyols. Also,

as discussed in an earlier response in this section,

§63.1427(j)(1)(i)(E) has been revised to specify that the EO/PO

ratio shall be determined at the end of the epoxide feed.

2.6 MONITORING REQUIREMENTS FOR PROCESS VENTS

2.6.1 Monitoring Requirement Exemptions for the Process Vent

Requirements
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Comment: One commenter (IV-D-05) stated that, according to

§63.1422(j), if the unit is otherwise exempt from performance

tests because it complies with another law, such as the Resource

Conservation and Recovery Act (RCRA) requirements, the owner or

operator will comply with the monitoring requirements of that

law. To clarify that §63.1429(a)(3) does not impose requirements

on equipment otherwise exempt from testing, the commenter

recommended adding the following wording to §63.1429(a)(3), such

that it reads:

"(3) Where a boiler or process heater of less than 44

megawatts design heat input capacity and not otherwise

exempt from performance testing under this subpart, is

used...."

Response: The EPA does not, in subpart PPP, exempt a boiler

from performance testing because it complies with another law. 

Section 63.1422(j) allows the owner or operator the choice of

whether to comply with the monitoring, recordkeeping and

reporting requirements of this rule or the RCRA rule, if both

apply. Therefore, the EPA believes the suggested change is

inappropriate, and has not made that change in the final rule.

2.6.2 Scrubber Monitoring Requirements

Comment: Three commenters (IV-D-03, IV-D-05, IV-D-07)

referred to §63.1429(a)(4) of the proposed rule which specifies

scrubbing liquid temperature and specific gravity as appropriate

monitoring parameters. The commenters stated that specific

gravity is not an appropriate parameter for "once through"

scrubber systems and should be deleted. It was recommended that

scrubbing liquid flow rate, which is a key parameter for most

scrubber systems, be added to this section in the final rule. 

Two other commenters (IV-D-05, IV-D-07) agreed, and also

suggested monitoring pH, if the scrubber is an assisted scrubber.
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Response: The Agency realizes that the scrubbers operated

at the polyether polyol production facilities are once-through

scrubbers, which are similar to those added after combustion

devices to reduce emissions of halogens. Therefore, the final

rule requires the same monitoring parameter requirements as for

halogen reduction scrubbers in the HON. Specifically, in the HON

[§63.114(a)(4)(i) and (ii)], a pH monitoring device to monitor

the pH of the scrubber effluent and a flow meter are required to

be used for scrubbers used with an incinerator, boiler, or

process heater in the case of halogenated vent streams. 

In the final rule, §63.1429(a)(4) reads:

“(4) Where an absorber is used, a scrubbing liquid flow

rate meter or a pressure temperature monitoring device and a

specific gravity monitoring device are required, each

equipped with a continuous recorder is required and should

be equipped with a continuous recorder. If an acid or base

absorbent is used, a pH monitoring device to monitor

scrubber effluent is also required. If two or more

absorbers in series are used, a scrubbing liquid flow rate

meter, or a pressure monitoring device, equipped with a

continuous recorder, is required for each absorber in the

series. An owner or operator may submit a request to

instead install the scrubbing liquid flow rate meter, or a

pressure monitoring device, equipped with a continuous

recorder, on only the final absorber in a series, in

accordance with the alternative parameter monitoring

reporting requirements in §63.1439(f).

2.6.3 Monitoring of Multiple Absorbers

Comment: One commenter (IV-D-05) maintained that

§63.1429(a)(4) does not indicate how monitoring is to be

performed where two or more absorbers are used, and requested

that EPA clarify this provision. 

Response: In general, the EPA believes that if multiple

scrubbers are used in series to achieve the required percent

efficiency, then it is important that the performance of each

scrubber be monitored. However, the EPA recognizes that there

could be circumstances where monitoring only one scrubber would
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be adequate. Under this circumstance, the EPA believes that a

request for alternative monitoring can be submitted in accordance

with §63.1439(f). The following language was added in

§63.1429(a)(4):

“If two or more absorbers in series are used, a scrubbing

liquid flow rate meter, or a pressure monitoring device,

equipped with a continuous recorder, is required for each

absorber in the series. An owner or operator may submit a

request to instead install the scrubbing liquid flow rate

meter, or a pressure monitoring device, equipped with a

continuous recorder, on only the final absorber in a series,

in accordance with §63.1439(f).”

2.6.4 Alternative to §63.1429(a)(7)

Comment: One commenter (IV-D-05) claimed that, in

§63.1429(a)(7), an organic monitor with a continuous recorder

should be acceptable as an alternative to §63.1429(a)(1) and

(a)(3) through (a)(6). This commenter recommended revising the

text in §63.1429(a)(7) as follows:

"(7) As an alternate to paragraphs (b)(4) through (b)(6)

(a)(1) and (a)(3) through (a)(6) of this section, the owner or

operator may install an organic monitoring device equipped with a

continuous recorder."

Response: The proposed rule allowed the monitoring of

organic compound concentration as an alternative to monitoring

operating parameters for absorbers, condensers, and carbon

adsorbers (as was required in paragraphs (a)(4), (5), and (6)). 

The commenter is requesting that the monitoring of organic

compound concentration also be allowed as an alternative to

monitoring operating parameters for incinerators and boilers or

process heaters (paragraphs (a)(1) and (3)). The EPA agrees with

the commenter that an organic monitor with a continuous recorder

could be an acceptable alternative to §63.1429(a)(1) and (3)

through (6) in some instances. However, the commenter did not

provide sufficient data or rationale on the monitoring of organic

compounds at the exit of combustion devices to convince the EPA

that such an alternative should be generally allowed in the final
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rule. However, the EPA believes that organic compound

concentration monitors can be used on a site-specific basis. 

Owners or operators wishing to monitor organic compound

concentration may submit a request to monitor these parameters in

accordance with the alternative monitoring parameters provisions

in §63.1439(f).

The EPA appreciates the commenter’s pointing out the crossreferencing error in the proposed rule. The cross-referencing

error was corrected in the final rule. 

2.6.5 Flow Indicator Specifications

Comment: Two commenters (IV-D-04, IV-D-05) requested that

the EPA delete the provisions of §63.1429(c)(3), which implied

that computer monitoring of a bypass line damper or valve

position [§63.1429(c)(3)] was different than operating a flow

indicator [§63.1429(c)(1)]. In addition, one commenter (IV-D-04)

recommended deleting two other paragraphs (or portions thereof)

that relate to §63.1429(c)(3) because, once §63.1429(c)(3) was

deleted, they would have no meaning:

(1) In §63.1430(d)(4), delete the words "or where computer

monitoring of the bypass damper or valve is used to comply with

§63.1429(c)(3)."

(2) Delete paragraph 63.1430(d)(4)(ii).

Response: The EPA removed the proposed paragraph

63.1429(c)(3). The EPA believed that §63.1429(c)(1) and (2) were

sufficient for specifying the monitoring requirements associated

with bypass lines, since the definition of a flow indicator in

subpart G includes computer monitoring. The other changes

mentioned by commenter IV-D-04 have also been made in the final

rule, as a result of the removal of §63.1429(c)(3), in order to

eliminate references to that paragraph which no longer exists in

the final rule.
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2.7 GROUP DETERMINATION FOR NONEPOXIDE HAP EMISSIONS

2.7.1 Group Determination Records When the TRE Index is

Between 1.0 and 4.0

Comment: One commenter (IV-D-04) referred to

§63.1428(h)(2)(ii), which requires a report if the TRE index

value after a process change is between 1.0 and 4.0. According

to the commenter, this seems to presume that, before the process

change, the TRE index value was greater than 4.0. Instead of

presuming it, the section should be specific. The commenter

claimed that industry should not have to submit a report if the

TRE index value was already between 1.0 and 4.0 before the

process change, and the value is still in that range after the

process change. The commenter suggested the following revisions

to §63.1428(h)(2)(ii):

"(ii) Where the recalculated TRE index value is less than or

equal to 1.0, or where the TRE index value before the process

change was greater than 4.0 and the recalculated TRE index value

is less than or equal to 4.0 but greater than 1.0, the owner or

operator shall submit a report ...."

Response: The Agency agrees with the commenter's revision

and has incorporated it into the final rule.

2.8 PROCESS VENT RECORDKEEPING AND REPORTING REQUIREMENTS

2.8.1 "Up-to-date" Process Vent Records

Comment: One commenter (IV-D-05) stated that §63.1430(b) and

§63.1430(f)(5) require records to be kept "up-to-date," but

stated that this term has no meaning for one-time records and is

unnecessary for recurring records, since owners or operators are

already required to obtain and retain each record when the time

arises. Therefore, the commenter is recommending that this term

be deleted.
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Response: The EPA has removed the phrase "up-to-date" from

these recordkeeping requirements in the final rule, because that

phrase did not actually state the frequency with which records

were to be "up-dated." The EPA feels that the proposed

regulatory text, minus the phrase "up-to-date", is sufficient to

convey the EPA's intent, which was that the owner or operator

keep these records current.

2.8.2 Flares Compliance Demonstration

Comment: Two commenters (IV-D-04, IV-D-05) expressed

concern that §§63.1430(b)(1)(ii) and (b)(1)(iii) imply that a

compliance demonstration for flares is required by §63.11(b) of

subpart A. They maintained that they have searched §63.11(b)

very carefully and cannot find anything in that section that

specifically requires a compliance demonstration. Therefore, the

commenters requested that, if EPA wants a compliance

demonstration for flares, that the requirement be included in the

final rule, specifying what elements are included in the

demonstration and what the deadline is. 

Response: At proposal, subpart PPP referred to §63.11(b) for

determining compliance with the flare requirements. However, as

the commenters have pointed out, §63.11(b) does not actually

require a compliance demonstration. To remedy this situation, in

the final rule the EPA has added a requirement to perform the

compliance demonstration for flares to §63.1437(c). Appropriate

changes have also been made in §63.1430(b)(1)(iii) and other

parts of the rule, to replace the HON reference to §63.11(b) with

a reference to the provisions in §63.1437(c).

In the final rule, the EPA has added §63.1437(c) to make it

clear that a compliance demonstration for flares must be

conducted using the provisions found in §63.11(b). Specifically,

the owner or operator is required to (1) conduct a visible

emission test, (2) determine the net heating value of the gas
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being combusted, and (3) determine the exit velocity. In each

case, the provisions specify that these parameters be determined

in accordance with specific paragraphs in §63.11. Section

63.1437(c) also specifies that an owner or operator is not

required to conduct a performance test to determine percent

emission reductions or outlet organic HAP or TOC concentrations

for flares. In addition, the final regulatory language specifies

that a previously conducted flare compliance demonstration may be

used to demonstrate compliance for the purposes of subpart PPP,

provided that no deliberate process changes have been made since

the compliance demonstration, or that the results of the

compliance demonstration reliably demonstrate compliance despite

process changes.

2.8.3 Records for Start-ups, Shutdowns, Malfunctions, and

Periods of Non-operation

Comment: Two commenters (IV-D-04, IV-D-05) maintained that

§63.1430(d)(2)(i) borrows some, but not all, of the relevant HON

amendments, and it should be revised to address start-ups,

shutdowns, malfunctions, and periods of non-operation of a

relevant portion of the process. Additionally, it should refer

to cessation of the monitored emissions, rather than emissions

generally. While it may be appropriate to record all data, the

commenters asserted that averages should exclude periods of

system start-up, shutdown, breakdowns, repairs, calibration

checks, and zero (low-level) and high-level adjustments. To be

consistent with the HON, the commenters recommended changing the

text. Commenter IV-D-05 provided revised wording and commenter

IV-D-04 supported the text suggested by commenter IV-D-05.

 Response: The EPA agreed that §63.1430(d)(2)(i) should

apply to “specific portions” of processes, and has amended the

language in §63.1430(d)(2)(i) accordingly. In addition, the EPA

has added a provision stating that monitoring data collected
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during periods of start-up, shutdown, or malfunction are not to

be included in the daily average. The EPA does not agree with

the commenters that this paragraph should depend only on the

cessation of “monitored emissions,” rather than on the cessation

of all emissions.

2.8.4 Records Related to Group Determination

Comment: One commenter (IV-D-05) supported not having to

develop unnecessary information in order to determine Group

status. Sources should have the discretion to designate

individual vents as Group 1 and skip the determination process. 

To reflect the EPA's intent in this regard, the commenter

recommended that a new sentence be added at the end of

§63.1430(e)(1) as follows:

"The owner or operator may elect Group 1 status for process

vents without making a Group 1/Group 2 determination. In such

event, no determination records are required."

Response: It is the EPA's intent to allow sources to

designate individual vents as Group 1 and skip the group

determination process. Since the commenter did not think that

§63.1430(e)(1) was clear enough in allowing for this option, the

Agency has added the modified version of the sentence that the

commenter suggested to the final rule, as follows:

“The owner or operator may elect Group 1 status for process

vents without making a Group 1/Group 2 determination. In

such event, none of the records specified in this paragraph

(e) are required.”

2.8.5 Recordkeeping Exemption

Comment: One commenter (IV-D-05) stated that

§63.1430(e)(1)(vi) and (e)(2) do not require certain records if

batch vents are in compliance with §63.1425(c)(1) (aggregate 90

percent HAP reduction) and the relevant compliance device is

operating at all times. This means that, if a source ever fails
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to get 90 percent, or if the device ever goes "down," there would

be a violation not only for failing to meet the 90 percent limit

but also for not having certain records that the source was

previously exempt from having to retain. Therefore, the

commenter recommended revising the text by adding a new sentence

at the end of each of §63.1430(e)(1)(vi) and (e)(2), as follows:

"(vi) ...This subparagraph (vi) applies even if the

affected source temporarily fails to meet the requirements

of §63.1425(c)(1) or the device does not function

temporarily."

"(2) This paragraph (2) applies even if the affected

source temporarily fails to meet the requirements of

§63.1425(c)(1) or the device does not function temporarily."

Response: The EPA understands the commenter’s concern about

being held liable for a double violation under the situation

described above. However, the EPA felt that the suggested

language was too vague (e.g., “temporarily” is not defined, and

no time frame is specified). The final rule resolves this

problem by replacing the phrase “[the] process vent is in

compliance with §63.1425(c)(1)” with the phrase “is subject to 

§63.1425(c)(1),” in §63.1430(e)(1)(vi). This change will prevent

the owner or operator from being in a double penalty situation,

while still offering the group determination recordkeeping

exemption to the owner or operator who is subject to

§63.1425(c)(1) or (c)(3). A similar change has been made to the

language in §63.1430(e)(2), such that the revised language

appears as follows:

(2) Process vents from continuous unit operationsVents

from Continuous Unit Operations. EachThe owner or operator

of an affected source that uses nonepoxide organic HAP to

make or modify a polyether polyol the product in continuous

unit operations shall keep records regarding the

measurements and calculations performed to determine the TRE

index value of the combined each process vent stream. The

owner Owners or operators of combined streams Group 1

continuous process vents that are in compliance withsubject

to the Group 1 requirements of §63.1425(c)(3) is are not

required to keep these records.
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2.8.6 Process Change Resulting in a Change in the TRE

Comment: One commenter (IV-D-05) requested that sources be

exempted from the reporting requirements of §63.1430(k) if there

is some other basis for exemption, such as a flow rate below

0.005 scmm or a HAP concentration less than 50 ppmv. Therefore,

the commenter recommended adding the following new paragraph at

§63.1430(k). Proposed §63.1430(k) would then become §63.1430(l). 

§63.1430(k) would read:

(k) The owner or operator is not required to submit a

report of a process change if one of the conditions listed in

paragraphs (k)(1) through (k)(4) of this section is met.

(1) The process change does not meet the definition of a

process change in subpart G; or

(2) The vent stream flow rate is recalculated according to

subpart G and the recalculated value is less than 0.005 standard

cubic meter per minute, or

(3) The organic HAP concentration of the vent stream is

recalculated according to subpart G and the recalculated value is

less than 50 parts per million by volume, or

(4) The TRE index value is recalculated according to subpart

G and the recalculated value is greater than 4.0.

Response: The EPA does not believe that the "exemptions"

cited by the commenter, (i.e., flow rate below 0.005 scmm or a

HAP concentration less than 50 ppmv) are appropriate for

§63.1430(k) as proposed. Since proposal this section was

renumbered §63.1430(j), where the owner or operator is subject to

the process vent reporting and recordkeeping requirements in

§63.1430 when a process change has occurred that causes a Group 2

continuous process vent with a TRE greater than 4.0 to become

Group 2 with a TRE less than 4.0. By definition (see §63.1423) a

Group 2 process vent from continuous unit operations is defined

as “...not classified as a Group 1 continuous process vent,” and

a Group 1 continuous process vent is defined as “(1) has a flow

rate greater than or equal to 0.005 standard cubic meters per

minute, and (2) has a total organic HAP concentration greater

than or equal to 50 parts per million by volume, and (3) has a

total resource effectiveness index value, calculated in
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accordance with §63.1428(h)(1), less than or equal to 1.0." The

exemptions cited by the commenter define the process vent as

being Group 2 and are not needed in §63.1430(j). Therefore,

§63.1430(j) of the final rule does not include the revisions

suggested by the commenter. 

2.9 EMISSION FACTOR

2.9.1 Emission Factor Plan

Comment: One commenter (IV-D-05) requested, for purposes of

clarity, that §63.1431(b)(1) be revised to refer to the use of a

combustion, recovery, or recapture device "without ECO," and that

§63.1431(b)(2) be revised to refer to the use of ECO "without a

combustion, recovery, or recapture device," since §63.1431(b)(3)

provides requirements for when both ECO and a combustion,

recovery, or recapture device are used. 

Response: The EPA has made this distinction in the final

rule. 

Comment: One commenter (IV-D-05) recommended, for purposes

of clarity, that the provisions of §63.1431(c)(2) be revised to

include the phrase "unless exempted by the provisions of this

subpart" as follows:

"The owner or operator shall conduct a performance test in

accordance with §63.1426 to determine the epoxide control

efficiency of the combustion, recovery, or recapture device

unless exempted by the provisions of this subpart...."

Response: Section 63.1426 lists the exemptions that apply,

so by citing §63.1426, the exemptions are also cited. Therefore,

the EPA does not find it necessary to make the requested revision

to §63.1431(c)(2).

2.10 STORAGE VESSEL

2.10.1 Storage Vessel Provisions
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Comment: One commenter (IV-D-05) referred to the language in

§63.1432(e), (f), and (h), which says that certain HON language

should be "replaced with" other language. For clarity, the

commenter requested that the text be changed to state that the

referenced language "applies," instead of saying that it

“replaces” language in the HON.

Response: The EPA appreciates the commenter’s input, and

has changed the referenced language in accordance with the

commenter’s suggestions, in the final rule. 

2.10.2 Previous Performance Testing of Storage Vessel Control

Device

Comment: Two commenters (IV-D-04 and IV-D-05) supported the

provisions in §63.1432(g) that state that if a storage vessel has

a control device that has been performance-tested for other

reasons, the prior performance test would satisfy the storage

vessel requirements of this rule. However, Commenter IV-D-04

stated that the provisions are unclear in the following two

areas, and should be clarified: 

(1) The text mentions control devices that are used to

comply with "§63.1425 through (sic.) §63.1433," which is

impossible. For one thing, the range of §63.1425 through

§63.1433 includes §63.1432, which is where the storage vessel

provisions are located. A control device on a storage vessel

cannot "also" be used for storage vessel compliance. Also, it is

unlikely that any single control device would be used

simultaneously for the entire range of sections from §63.1425

through §63.1433. The commenter believed that the EPA meant to

say that, if the control device had already been performancetested under any one of those sections, no further demonstration

is required. 

(2) The provisions accept only performance tests "required

by" specified sections of the rule. However, those sections do
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not always "require" performance tests; sometimes they "allow"

performance tests, such as when a test that is conducted to

comply with other regulations promulgated by the EPA is allowed

to be used. If the control device has been performance-tested

under some NSPS or NESHAP using the same reference methods, and

if the results are still reliable, the commenter claimed that the

previously conducted performance test should be acceptable. 

Response: The EPA agrees with the commenters on both of

these points, and has made changes to §63.1432(g), accordingly. 

The regulatory language in the final rule reads as follows: 

(g) EachThe owner or operator of an affected source

shall comply with this paragraph instead of

§63.120(d)(1)(ii) of subpart G for the purposes of this

subpart. If the combustion, recovery, or recapture device

used to comply with §63.119(e) is also used to comply with

any of the requirements found in §§63.1425 through 63.1431

and/or §63.1433, the performance test required in or

accepted by for §§63.1425 through 63.1431 and/or §63.1433 is

acceptable for demonstrating compliance with §63.119(e) of

subpart G, for the purposes of this subpart. The owner or

operator will not be required to prepare a design evaluation

for the combustion, recovery, or recapture device as

described in §63.120(d)(1)(i) of subpart G, if the

performance test meets the criteria specified in paragraphs

(g)(1) and (g)(2) of this section. 

2.11 WASTEWATER PROVISIONS

2.11.1 Wastewater Cross-Referencing with the HON

Comment: One commenter (IV-D-07) asserted that the crossreferences provided in §63.1433 of the proposed rule are very

complex, make compliance difficult, and might cause inadvertent

violations. The commenter urged the EPA to develop a

comprehensive set of requirements for this section of the rule.

Response: In the final rule, the EPA has maintained the

cross-references to the HON wastewater provisions. The EPA

recognizes that a complex system of cross-referencing can be
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confusing to the owner or operator. However, the EPA considers

the benefit to industry [which is derived from the fact that a

company producing products subject to several rules (e.g., the

HON, subpart JJJ, and subpart U) can rely on the fact that their

wastewater equipment will be subject to the same basic control

requirements] to outweigh the negative effects that this

structure might have on those same owners or operators. This is

particularly important in consideration of the fact that

wastewater may originate at process units producing several

different products, and yet be combined into an individual stream

prior to treatment. Each NESHAP should spell out the specific

requirements for such a wastewater stream, but the owner or

operator’s job will be simplified if the basic control

requirements applying to wastewater streams from the different

types of process units are the same, or at least very similar. 

In addition, the EPA has received positive feedback regarding

this strategy for dealing with process wastewater from other

industry representatives.

2.11.2 Definition of Wastewater in the Basis and Purpose for

Proposed Standards

Comment: One commenter (IV-D-07) requested that the EPA

clarify one statement that was made in section 2.5.3, Wastewater

Operation, of the Basis and Purpose for Proposed Standards

(Document no. EPA-453/R-97-010a, May 1997). The commenter

claimed that one statement in that section omitted an important

part of the wording from the definition of wastewater that was

included in subparts F and G (the wastewater model for this

rule), that wastewater exists after it is discarded, not after it

exits a piece of equipment. Furthermore, the commenter

maintained that a wastewater stream is considered to be discarded

after it exits the last recovery device in a PMPU. The commenter

requested that the EPA clarify in its response to comments
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document that wastewater exists after it is discarded from the

PMPU.

Response: The commenter is correct, and the EPA would like

to make note of the fact that the definition of “wastewater” in

subpart PPP continues to mirror the definition of “wastewater” 

in §63.111 of the HON, which contains the concept of the fluid

having been "discarded" from a process unit. The "discard"

concept is fundamental in determining which fluids exiting the

PMPU are subject to the wastewater provisions in §63.1433. In

addition, in the final rule the definition of “wastewater” has

been corrected to refer to Table 4 of subpart PPP (instead of

Table 5, which it incorrectly referenced at proposal).

2.11.3 Classification of Wastewater Receiving Facilities

Comment: Three commenters (IV-D-04, IV-D-05, IV-D-07)

requested that the EPA clarify that when facilities use the HON’s

third-party wastewater treatment provisions, the receiving

facility does not become subject to the Off-Site Waste and

Recovery Operations MACT rule (subpart DD). One commenter (IV-D04) claimed that there is a disconnect between the proposed rule

and subpart DD, because subpart DD’s exemption mentions only the

HON, not other rules that make slight changes to the HON (such as

different compliance dates, slight changes in definitions, and

different chemical lists). Therefore, the commenter recommended

adding a paragraph (d) to §63.1433 as follows:

(d) The owner or operator of a facility which receives

a Group 1 wastewater stream, or a residual removed from a

Group 1 wastewater stream, for treatment pursuant to

§63.132(g) of subpart G as referenced in paragraph (a) of

this section, is subject to the requirements of §63.132(g)

with the differences identified in this section, and is not

subject to subpart DD of this part with respect to that

material.
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Response: The EPA agrees that this clarification needed to

be added to the final rule. The final rule contains language

very similar to that suggest by the commenters, in

§63.1433(a)(20), with the exception that the cross references are

omitted. The new language reads as follows:

(20) The owner or operator of a facility which

receives a Group 1 wastewater stream, or a residual removed

from a Group 1 wastewater stream, for treatment pursuant to

§63.132(g) is subject to the requirements of §63.132(g),

with the differences identified in this section, and is not

subject to subpart DD of this part, with respect to the

received material.

2.11.4 Clarifying the Definition of Residuals

Comment: One commenter (IV-D-04) requested that the EPA

clarify that residuals are not process wastewater. The commenter

referenced the proposal preamble (62 FR 46810, col. 3), which

stated that one example of a process wastewater stream is

"residuals recovered from waste management units." The commenter

considered this statement problematic because a residual is not a

process wastewater stream and not every residual is regulated. 

The commenter asserted that the regulations should only apply to

residuals from Group 1 process wastewater streams; residuals from

Group 2 streams should not be regulated.

Response: The Agency agrees with this commenter. The

preamble to the final rule clarifies that residuals recovered

from waste management units do not necessarily constitute an

example of process wastewater.

2.11.5 Wastewater Control Options

Comment: One commenter (IV-D-04) requested that the EPA

clarify that, for an individual emission point, emission

suppression does not always require the combination of a cover,

an enclosure, and a closed-vent system to a control device. This

is the commenter’s interpretation of the following statement in
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the proposal preamble (62 FR 46811, col. 2): "Suppression of

emissions from the point of determination to the treatment device

will be achieved by using covers and enclosures and closed-vent

systems to collect organic HAP vapors from the wastewater and

convey them to treatment devices."

Response: The commenter is correct, in that individual

emission points do not require a cover and an enclosure and a

closed-vent system to a control device. The final preamble

states that individual emission points require a control device,

or a seal/cover/enclosure that may be routed to a control device,

depending on the source.

2.11.6 "Inprocess" Aqueous Streams Should not be Identified as

Wastewater Streams

Comment: One commenter (IV-D-04) claimed that there is a

mismatch in §63.1433(a) and §63.1433(a)(10). Section 63.1433(a)

refers to "each process wastewater stream" and requires

compliance with HON §63.132 through §63.149. However, §63.149

does not deal with process wastewater streams, it deals with

certain in-process aqueous streams in open equipment. The

commenter asserted that nothing is wastewater until it leaves the

process. Similarly, §63.1433(a)(10) says certain definitions

apply whenever HON §63.132 through §63.149 refer to a Group 1

wastewater stream or to a Group 2 wastewater stream. However,

§63.149 applies to certain in-process (non-wastewater) aqueous

streams in open equipment. The commenter recommended that

§63.1433(a) and (a)(10) be revised as follows:

"(a) For each process wastewater stream originating at

an affected source, the owner or operator shall comply with

the requirements of §63.132 through §63.1497 of subpart G,

with the differences noted in paragraphs (a)(1) through

(a)(19), and (b) and (c) of this section, for the purposes

of this subpart. The owner or operator shall comply with

the requirements of §63.149 of subpart G, with the

differences noted in paragraphs (a)(1), (a)(2), (a)(7),
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(a)(8), (a)(11) and (a)(12) of this section, for equipment

meeting the criteria of §63.149 of subpart G as modified by

those differences.” 

"(10) Whenever §63.132 through §63.149 §63.147 of

subpart G refer to a Group 1 wastewater stream or a Group 2

wastewater stream, the definitions of the terms contained in

§63.1423 shall apply, for the purposes of this subpart."

Response: The EPA agrees with the general concept behind

commenter IV-D-04's comment. However, the EPA does not feel that

it is necessary to list each paragraph that corresponds to either

wastewater streams or “in process” equipment, as the commenter

suggested. Instead, the EPA has added language clarifying that

the owner or operator must comply with the requirements in

§63.148 for leak inspection provisions, and with the requirements

of §63.149 for equipment that is subject to §63.149. The final

rule also clarifies that the owner or operator must comply with

the requirements in §63.105(a) for maintenance wastewater. The

EPA has also made the distinction between the §63.132 through

§63.147 requirements and the §63.149 requirements, as the

commenter requested.

2.11.7 Selection of Compounds Subject to the Wastewater

Provisions

Comment: One commenter (IV-D-07) supported regulating

wastewater for only the list of organic HAP in Table 4 of Subpart

PPP; however, the commenter requested that the EPA establish a

Henry’s Law Constant "de minimis" value and delete non-volatile

organic HAP, such as methanol, from Table 4 as it applies to the

wastewater provisions. The commenter stated that EPA has deleted

other organic HAP from lists of regulated organic HAP under the

wastewater provisions in the HON and other rules, based on the

insignificant potential of those organic HAP to volatilize from

wastewater, and based on the knowledge that those organic HAP are

highly biologically degradable. The commenter noted that a “de

minimis” value of 1.8 x 10 atm m /gmole fraction at 25 EC was -6 3
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used in the HON. The commenter provided examples of chemicals

that have been deleted from the list of regulated organic HAP

under the HON or other rules, including diethanolamine, ethylene

glycol, and formaldehyde. The commenter stated that comments

submitted by the pharmaceutical industry on the proposed MACT

standard affecting their industry showed that methanol has a

higher function of biological degradation than that estimated by

the EPA. The commenter recommended that the EPA (1) reevaluate

the emissions estimates and significance of the Table 4 organic

HAPs to volatilize from wastewater, (2) determine those organic

HAP that should be excluded because of their high degree of

biological degradation, and (3) delete the organic HAP meeting

those two criteria from the list of regulated organic HAP in

Table 4. 

Response: The commenter incorrectly stated that the

compounds in table 4 of subpart PPP are subject to the wastewater

provisions. As stated in §63.1433(a)(2), when subpart G (the HON

wastewater provisions in subpart PPP) refers to table 9 or table

36, the owner or operator is only required to consider organic

HAP listed in table 9 or table 36 of subpart G that are also

listed in table 4 (actually, the proposed rule stated "table 5,"

which was a typographical error) of this subpart. In other

words, only compounds that are both on Table 4 of subpart PPP and

on Table 9 of subpart G are subject to the wastewater provisions. 

By doing this, the EPA has eliminated (from the wastewater

provisions) those organic HAP that were eliminated from the HON

tables due to their low volatility. Therefore, the EPA did not

find it necessary to delete any compounds from table 4 of the

final rule.

2.11.8 Wastewater Nationwide Baseline Emissions Estimate: 

Steam Jet System’s Condensate Estimate
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Comment: One commenter (IV-D-07) questioned the data and

wastewater emission estimates in the Supplementary Information

Document (SID) for the national baseline emissions, and stated,

in particular, that the EPA had overestimated the nationwide

emissions from wastewater from polyether polyols production. The

commenter cited two issues related to the data presented in Table

9 of the April 29, 1996 memorandum (Docket Item II-B-5),

regarding nationwide baseline emissions. 

First, the commenter stated that the "average organic HAP

concentration" of 70,000 ppmv of PO is inconsistent with the

commenter’s operating and engineering experience of steam jet

ejector systems, and noted that the volatile organic HAP

concentration in steam condensate tends to be in the range of 10

to 500 ppmv. The commenter noted that the memorandum in the

docket (II-B-5) was unclear about whether the data gathered from

“vacuum systems” to determine the average concentration of

organic HAP were from a single stream, or from a combination of

several streams. The commenter recommended that the EPA gather

more accurate information on steam jet system’s condensate, and

base the estimate on an adequate representation of the systems. 

The commenter's second concern was whether the EPA had

relied on one data point to inappropriately extrapolate emissions

from the model stream to nationwide emissions. The commenter

also noted that the nationwide emissions from this one model

stream accounted for 68 percent of wastewater emissions, and 42

percent of the total nationwide emissions from polyether polyols

production.

Response: The commenter's first concern was that the PO

concentration in the vacuum system model stream (70,000 ppmv) was

inconsistent with the commenter's knowledge of the industry,

which would indicate that the PO concentration in these streams

is in the range of 10 tp 500 ppmv. It is the EPA's understanding

that the commenter's experience has been with vacuum systems with
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low HAP concentrations, which were not included in the EPA’s

database. Data provided by industry in responses to the

questionnaire were used to create the database. The

questionnaire stated that it applied to HAP emission sources

generated by polyether polyol production processes, except for:

(1) wastewater streams with an annual average flow rate less than

0.1 gallons per minute, or a total HAP content less than 10 ppmv,

or (2) waste with a total HAP content less than 10 ppmv or a

generation rate less than 220 pounds per month. Therefore, the

concentrations reported in response to the EPA/SPI questionnaire

were only for the more concentrated streams. The EPA took this

bias into account when estimating nationwide baseline emissions,

by multiplying the percentage of facilities with more

concentrated wastewater streams (58 percent) by the emissions

from the model stream and the estimated number of facilities in

the nation. The concentration, of 79,000 ppmv, cited in the

memorandum (Docket Item II-B-5) was based on actual data provided

from 7 facilities' responses to the wastewater section of the

EPA/SPI questionnaire. Therefore, the EPA believes that the PO

concentration (70,000 ppmv) in the vacuum system wastewater model

streams is representative. 

2.11.9 Wastewater Nationwide Baseline Emissions Estimate: The

Fraction Emitted Factors Used

Comment: One commenter (IV-D-07) voiced two concerns over

the fraction emitted (Fe) factors used to determine an emission

estimate. The commenter's first concern was that it was unclear

if an "average" Fe was used or if the Fe specific to each

chemical was applied to each specific organic HAP identified in

the wastewater stream. The commenter's second concern was that

the EPA did not update the fraction emitted factors (Fe) from

those used in the HON Table 34. Therefore, the commenter

requested that the EPA determine the emissions for each specific

organic HAP to which subpart PPP applies, before averaging the Fe
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factors, or averaging the organic HAP concentrations, and that

the EPA update the Fe factor to reflect these new calculations.

Response: In response to the commenter's question, for each

model wastewater stream, an emission rate was calculated for the

seven facilities in the database, from which weighted average

emission rate, flow rate and concentrations were calculated. An

individual Fe (from Table 34 of the HON) was assigned to each

model wastewater stream, corresponding to the predominant organic

HAP identified for that model wastewater stream (i.e., toluene

with an Fe of 0.8, EO with an Fe of 0.5, and PO with an Fe 0.6). 

No revisions were made to the model wastewater streams, the

calculations, or the baseline nationwide wastewater emissions,

because these emission estimates used the Fe's from table 34 of

the HON, which has not been amended since promulgation of the HON

on April 22, 1994, and which the EPA considers to be consistent

with current organic HAP information.

2.11.10 Inclusion of Biological Treatment as Wastewater Control

Option

Comment: One commenter (IV-D-07) noted that the EPA had

recently (at the time that the commenter’s statement was made)

proposed changes for wastewater compliance provisions using

biological treatment under the HON. After the HON was 

promulgated, the commenter requested that the EPA allow industry

representatives to comment on how the final changes to the HON

rule would affect subpart PPP. 

Response: The EPA did propose clarifications to the HON on

August 22, 1997 (62 FR 44608). These proposed clarifications,

which are slated to go final in the near future, dealt with a

very narrow portion of the HON wastewater provisions. In

particular, the EPA proposed to revise the definition of

“enhanced biological treatment systems or enhanced biological
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treatment processes,” in order to clarify the meaning of the

term, and it proposed to revise appendix C of part 63 to reflect

the clarification of the definition of “enhanced biological

treatment systems or enhanced biological treatment processes.” 

The EPA involved industry representatives in the revision of the

definition of “enhanced biological treatment systems or enhanced

biological treatment processes,” and the promulgated

clarification will incorporate public comments on the proposed

clarification, as necessary. For these reasons, the EPA does not

believe that it is necessary to request further comments on how

those changes to the HON wastewater provisions might affect

owners and operators of polyether polyols affected sources. The

EPA would, however, like to clarify (here and in the preamble to

the final rule) that the provisions of subpart PPP that crossreference the HON or any other regulation refer to the most

recent, promulgated versions of those rules, and that commenters

are encouraged to provide comments on any future proposed changes

to those rules cross-referenced in subpart PPP, with regard to

how those proposed changes might affect subpart PPP sources. 

2.11.11 PEPO Chemical List Versus HON's Table 8

Comment: Commenter IV-D-04 noted that §63.1433(b) should

have a “heading,” to call attention to the fact that it contains

the requirements for maintenance wastewater, and noted that

§63.1433(b) mentions only one difference from the HON. That

difference was that owners and operators of polyether polyols

affected sources should use the proposed polyether polyols rule’s

definition of "organic HAP," instead of the HON definition of

that term. However, according to the commenter, other

differences from the HON should be listed, such as the fact that

maintenance wastewater is a subset of "wastewater," and

"wastewater" has criteria that depend on chemical lists. 

Therefore, the commenter requested that the EPA clarify that, for

the purposes of subpart PPP, the PEPO chemical list (Table 4)
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applies, rather than HON Table 8 and/or Table 9 chemicals, and

also that PEPO focuses only on a subset of HON Table 9 chemicals,

while Table 8 in the HON does not apply to polyether polyols

affected sources. 

Response: The EPA agrees that there is a need for further

clarification in §63.1433(b), through the use of a “heading,” and

with regard to how the maintenance wastewater requirements in

§63.105 of subpart F apply to polyether polyols affected sources. 

Therefore, in the final rule, §63.1433(b) is amended to read as

follows:

(b) Maintenance wastewater. The owner or operator of

each affected source shall comply with the requirements for

maintenance wastewater in §63.105 of subpart F, except that

when with the exceptions noted in paragraphs (b)(1), (2),

and (3) of this section. 

(1) When the HON wastewater provisions in §63.105(a)

refers to "organic HAPs," the definition of “organic HAP” in

§63.1423 shall apply, for the purposes of this subpart.

(2) When the term “maintenance wastewater” is used in

§63.105, the definition of “maintenance wastewater” in

§63.1423 shall apply, for the purposes of this subpart.

(3) When the term “wastewater” is used in §63.105, the

definition of “wastewater” in §63.1423 shall apply, for the

purposes of this subpart.

2.12 EQUIPMENT LEAK PROVISIONS

2.12.1 Method 21 for Equipment Leak Detection

Comment: One commenter (IV-D-04) maintained that the

statement in the proposal preamble (62 FR 46812, col. 2) that

"The equipment leak standards require the use of Method 21 of

Appendix A of part 60 to detect leaks" is not quite correct. The

commenter stated that the equipment leak standards require

compliance with subpart H, which requires a slightly modified

version of Method 21, and anyone using Method 21 in its

unmodified state might not comply with subpart H.
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Response: The EPA agrees with the commenter. The proposal

preamble incorrectly stated that the HON requires the use of

Method 21, without mentioning that the detection instrument

response factor criteria in section 3.1.2(a) of Method 21 must be

for the average composition of the process fluid, instead of for

each individual VOC in the stream. The EPA apologizes for this

oversight in the proposal preamble, and wishes to clarify that

all of the equipment leak standards in subpart H apply to

polyether polyols affected sources, with the exceptions noted in

§63.1434.

2.12.2 "Delay of Repair" Example in the Preamble

Comment: One commenter (IV-D-04) questioned the fourth

example given in the proposal preamble (62 FR 46812, col. 1) for

situations where "delay of repair" may be allowed. The example

seems to say that single seals have better performance, and that

the EPA is replacing them with less desirable dual seals. The

commenter believed the opposite would be more accurate.

Response: The EPA agrees that the fourth example could be

misleading: the confusion results from the apparent omission of

a phrase from example number four. The fourth example of an

acceptable delay of repair beyond the required period should have

read "When equipment is being replaced by equipment with better

leak performance, such as when a pump with single mechanical

seals is being replaced with a pump with dual mechanical seals."

2.12.3 Cost-Effective Alternatives to the HON LDAR

Comment: One commenter (IV-D-08) urged the EPA to consider

more cost effective alternatives to the HON leak detection and

repair program (LDAR) in this and future MACT rules. The

commenter had previously submitted material to the EPA,

demonstrating that the initial leak rate assumptions in the HON

considerably overestimate actual leak rates in many instances. 
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Since cost effectiveness assumptions of the HON LDAR program are

based in part on initial leak rate estimates, the commenter is

concerned that the HON LDAR requirements do not represent the

most effective method of achieving reductions from fugitive

sources.

Response: The EPA appreciates the comment, but would like

to point out that the MACT floor level of control for subpart PPP

was determined to be the HON level of control. Because the cost

effectiveness of this level of control is not relevant in setting

the MACT floor level of control, the EPA did not consider all

methods of achieving reductions from fugitive sources. Further,

the EPA would like to point the commenter to §63.177(e) of part

G, which address obtaining approval from the Administrator to

utilize alternative means of emission limitations for equipment

leaks. 

2.12.4 De minimis Equipment Count

Comment: One commenter (IV-D-09) has provided an analysis

to EPA that they believe shows that it is not cost-effective to

do equipment leak survey programs for less than 100 components,

unless a source has other facilities on site which can offset the

cost of purchasing a monitoring device.

Response: The EPA evaluated the cost effectiveness of

performing the HON level of LDAR to a facility with 100 equipment

components, for facilities with and without monitors on-site. 

The documentation is provided in docket item number IV-B-01. The

cost-effectiveness values ranged from $2,900 to $3,300 for

facilities that previously controlled to the CTG level of

control, and ranged from $3,000 to 3,500 for facilities that were

uncontrolled. The EPA concluded that controlling facilities with

100 equipment components is cost effective, and made no revisions

to the rule.
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2.12.5 Applicability of Subpart I

Comment: One commenter (IV-D-05) maintained that §63.1434(c)

should discuss "resetting the clock" for sources in a quality

Improvement Program (QIP) under subpart I, as do other part 63

rules.

Response: The EPA agrees, and has incorporated language

that parallels that used in other part 63 rules, by adding the

following sentence to the end of §63.1434(c):

“However, sources subject to 40 CFR part 63, subpart I

that have elected to comply through a quality

improvement program, as specified in §63.175 or §63.176

or both of subpart H, may elect to continue these

programs without interruption as a means of complying

with this subpart. In other words, becoming subject to

this subpart does not restart or reset the "compliance

clock" as it relates to reduced burden earned through a

quality improvement program.”

2.12.6 Inclusion of Phase-in Option

Comment: One commenter (IV-D-05) stated that §63.1434 does

not address the phase-in issue, and that failure to address this

issue created a compliance problem in the implementation of

subpart U, which resulted in a subsequent change to that rule. 

To avoid a similar problem in this rule, the commenter suggested

adding language similar to newly proposed §63.502(m) from subpart

U as §63.1434(h), as follows:

(h) The owner or operator of each affected source shall

substitute the phrase "the provisions of subparts F, I, or PPP of

this part" for both the phrases "the provisions of subparts F or

I of this part" and the phrase "the provisions of subpart F or I

of this part" throughout §63.163 and §63.168, for the purposes of

this subpart. In addition, the owner or operator of each

affected source shall substitute the phrase "subparts F, I, and

PPP" for the phrase "subparts F and I" in §63.174(c)(2)(iii), for

the purposes of this subpart.

Response: The EPA agrees that the suggested text would

clarify how the requirements in subpart H of the HON apply to

owners and operators of polyether polyols production affected
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sources. A slightly modified version of the suggested text has

been added as §63.1434(h), as the commenter requested.

2.12.7 Exemption for Heat Exchanger Units not Using HAP

Comment: One commenter (IV-D-05) requested that §63.1435(a)

be revised to exempt PMPUs that do not produce or use any organic

HAPs. This commenter also requested that §63.1435(b), in both

parts of the sentence where it occurs, be modified as follows:

"...the term ‘polyether polyols manufacturing process unit,

except those that do not manufacture or use any organic HAP,’

shall apply for purposes of this subpart."

Response: The EPA agrees with the intent of the commenter’s

suggestion, but finds it simpler and more accurate to refer back

to the exemption in §63.1420(b), for PMPU without organic HAP. 

Therefore, in the final rule §63.1435(b) has been revised so that

the last sentence reads:

“Further, when the phrase "a chemical manufacturing

process unit meeting the conditions of §63.100(b)(1)

through (b)(3) of this subpart, except for chemical

manufacturing process units meeting the condition

specified in §63.100(c) of this subpart" is used in

§63.104(a) of subpart F, the term "polyether polyols

manufacturing process unit PMPU, except for PMPUs

meeting the conditions specified in §63.1420(b)” shall

apply for the purposes of this subpart.” 

2.13 TESTING

2.13.1 Consistency Between the Test Method Required in the

Proposed Rule and the Test Method Used to Establish the

New Source Process Vent MACT Floor

Comment: One commenter (IV-D-04) stated that the EPA has

proposed a 99.9 percent emission reduction for new sources based

on a performance test for Facility M. However, the proposed rule

also requires performance tests using Method 18. According to

the commenter, the performance test for Facility M did not rely

entirely on Method 18. Method 18 was used at the inlet, but
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Method 25A was used at the outlet. The proposed rule seems to

say that Method 25A may not be used, unless it is validated under

Method 301. Thus, the commenter interpreted that Facility M has

not conducted an acceptable performance test to be used as the

basis for the proposed standard. The commenter maintained that

if the performance test already conducted for Facility M was good

enough to be the basis for the rule, it should be good enough to

satisfy the performance testing requirements of the rule. The

commenter requested that the EPA clarify that Facility M is not

required to conduct another performance test.

Response: As discussed in the next response, the EPA has

revised the test methods allowed in the final rule. Based on the

review of the test report for Facility M’s test, the EPA believes

that the test was conducted in accordance with the revised

testing procedures. However, paragraph §63.1426(b)(3) of the

final rule contains an exemption from performance testing for

process vents based on the use of previous tests. Whether

Facility M would be required to conduct another performance test

would ultimately depend on whether the conditions of

§63.1426(b)(3) are met.

2.13.2 Use of Method 25A Without Method 301 Validation

Comment: Three commenters (IV-D-04, IV-D-05, IV-D-08)

requested that the EPA clarify that owners or operators may use

Method 25A without the need for validation under Method 301. 

According to §63.1437(b), any analytical method, other than

Method 18, used for performance tests would have to be validated

according to the protocol in Method 301. Two of the commenters

(IV-D-04, IV-D-05) presented the following reasons why Method 301

validation should not be required if the owners or operators uses

Method 25A for the performance test.

1. In establishing MACT for new sources, the EPA relied on

a performance test for Facility M, which used Method 25A on the
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outlet emissions. If the EPA found the data from Method 25A

sufficiently credible and valid to make those data the basis for

the rule, then the EPA cannot now say Method 25A is

insufficiently credible for use in performance tests.

2. Validation under Method 301 is incredibly and needlessly

burdensome. One commenter noted that they have been validating

analytical methods for years, without Method 301, quickly and

inexpensively. In contrast, validation under the Method 301

protocol is so burdensome and time-consuming as to be nearly

impossible.

3. The proposed rule relied on Method 25A in other

contexts. For example, §63.1433(a)(19) specified conditions

under which Method 25A may be used, as an alternative to Method

18, for wastewater. If Method 25A is appropriate for wastewater,

it should be appropriate for performance tests.

4. Commenter (IV-D-05) noted that Method 25A is allowed in

the Polymers and Resins IV rule without validation through Method

301. This commenter recommended revising §63.1426(c)(3) and

(c)(4) to allow the use of Method 25A without Method 301

validation.

One commenter (IV-D-08) requested that if the EPA keeps the

validation requirement, then the “abbreviated” version of Method

301 that was allowed in the HON wastewater provisions should also

be allowed under subpart PPP.

Response: The EPA agrees that allowing of the use of Method

25A would provide more flexibility, and potentially provide the

opportunity for less costly testing. However, the EPA believes

that Method 25A should be used only after an accurate response

factor has been determined. The importance of calibrating a

flame ionization detector (FID) reading obtained using Method 25A

with respect to a certain compound (adjustment by response

factor) depends on how the Method will be used to demonstrate

compliance with the standard. In general, the EPA believes that
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an accurate response factor is necessary in cases where Method

25A is used to demonstrate control efficiency across a device

where the composition of the stream may change, or in situations

where multiple components, including non-HAP VOC, are present. 

Because the relative proportion of organic compounds may change

across the control device, appropriate response factors are

needed to accurately quantify TOC at the inlet and outlet of a

control device. In addition, the EPA believes that owners and

operators should have the opportunity to demonstrate compliance

at the outlet of a control device by measuring 20 ppmv TOC or

less. Therefore, the final rule does allow the use of Method 25A

under certain conditions. The following describes the choices of

test methods allowed in the final rule: (1) Method 18 (40 CFR

part 60, appendix A) to determine HAP concentration in any

control device efficiency determination; (2) Method 25 (40 CFR

part 60, appendix A) to determine total gaseous nonmethane

organic concentration for control efficiency determinations in

combustion devices; (3) Method 25A (40 CFR part 60, appendix A)

to determine the HAP or TOC concentration for control device

efficiency determinations under the conditions specified in

Method 25 (40 CFR part 60, appendix A) for direct measurement of

an effluent with a flame ionization detector, or in demonstrating

compliance with the 20 ppmv TOC outlet standard. As an

alternative, any other method or data that have been validated

according to the applicable procedures in Method 301 (40 CFR part

63, appendix A) may be used.

2.13.3 Allow any Testing to Demonstrate Compliance

Comment: One commenter (IV-D-06) referred to §63.1426(b)(3),

which allows for an exception to the performance test

requirements if testing was previously conducted for determining

compliance with a regulation promulgated by EPA. The commenter

requested that this provision be amended to allow the use of any

representative testing conducted using methods specified in this
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standard, and not just the use of compliance testing conducted

for compliance with promulgated EPA regulations. The commenter

pointed that the cost per facility for retesting is approximately

$100,000.

Response: The EPA has agreed to grant the commenter’s

request. If the facility used the appropriate standardized EPA

method, the EPA agrees that it should not matter whether the

method was used to determine compliance with a regulation already

promulgated by the EPA or for some other purpose. Therefore, the

provision has been revised to allow the use of any representative

testing conducted using methods specified in this standard. The

revision does include a 5-year limit on the age of the test

report, along with assurances that the process is still operating

under similar conditions as those that it was operating under

during the test. Further, the original test would need to have

monitored operating parameters that could be used to comply with

the parametric monitoring requirements in subpart PPP.

2.13.4 Notice for Rescheduling of a Test

Comment: One commenter (IV-D-05) recommended, for

consistency with other rules, that the text in §63.1437(a)(4) be

changed to add the following sentence: "If the owner or operator

reschedules the test for any reason, it must provide the

Administrator 7 days’ notice."

Response: The EPA has added language to §63.1437(a)(4) in

the final rule, in order to specify that the owner or operator

needs to give the Administrator at least 7 days notice (prior to

the originally scheduled performance test) if a performance test

needs to be rescheduled. The changes to this paragraph also

allow the performance test to be rescheduled by mutual agreement

between the Administrator and the owner or operator, if

necessary.
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2.13.5 Engineering Calculations for Worst-case Requirements

Comment: One commenter (IV-D-03) recommended that

engineering calculations be allowed to establish "worst case"

parameter monitoring requirements when conducted in association

with an EPA approved stack test. 

Response: The use of engineering calculations, coupled with

an EPA-approved stack test, to establish parametric monitoring

requirements was already allowed in the proposed rule. The

proposed language in §63.1438(a) was very explicit about which

procedures (i.e., those contained in §63.1438(b), (c), or (d))

were permissible under varying circumstances. Specifically,

§63.1438(b) and (c) could be used by owners or operators to set

their parameter monitoring levels for a combustion, recovery, or

recapture device, if a performance test was required by subpart

PPP for that device. At proposal, it was not clear that

§63.1438(b) [and only §63.1438(b)] applied to owners or operators

desiring to set their parameter monitoring levels based

exclusively on parameter values determined during the performance

test. This has been clarified in §63.1438(b) in the final rule. 

As §63.1438(c) read at proposal (and continues to read),

parameter monitoring levels established under this paragraph are

to be based on the parameter values measured during a performance

test, supplemented by engineering assessments and (or)

manufacturer’s recommendations. In addition, §63.1438(b), (c),

or (d) may be used by owners or operators to set their parameter

monitoring levels for a combustion, recovery, or recapture

device, if a performance test is not required by this subpart for

that device. As §63.1438(d) read at proposal (and continues to

read), parameter monitoring levels may be established, under this

paragraph, based solely on engineering assessments and/or

manufacturer’s recommendations. 

However, in reviewing these requirements, the EPA did notice

one discrepancy in the proposed version of §63.1438(a), which
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needed correcting in the final rule. At proposal, §63.1438(a)

required that owners or operators using §63.1438(c) or (d) to

establish their parameter monitoring levels submit the

information specified in “§63.506(e)(3)(vii)” for review and

approval, as part of the Precompliance Report. This reference to

a reporting requirement in subpart U of part 63 was a mistake,

which has been remedied in the final rule. The correct reference

is to §63.1439(e)(4)(viii) in the final rule, which has been

added to that section and lists the following information to be

submitted in the Precompliance Report: (1) identification of

which procedure (i.e., §63.1438(c) or (d)) is to be used; and (2)

a description of how the parameter monitoring level is to be

established, using those procedures.

The request to use §63.1438(c) or (d) for the establishment

of parameter monitoring levels is subject to review and approval

(or disapproval) by the Administrator; however, as the final rule

states in §63.1439(e)(4)(i), unless the Administrator objects to

a request submitted in the Precompliance Report within 45 days

after its receipt, the request shall be deemed approved. This

means that the amount of time that the owner or operator would

have to wait for a response to the request to use §63.1438(c) or

(d) is limited to a maximum of 45 days.

2.13.6 Daily Averages versus Compliance

Comment: One commenter (IV-D-04) noted that §63.1438(a)(1)

requires that the daily average value of monitored parameters be

kept within the established limit, which the commenter believes

is generally appropriate. However, the commenter gave some

examples of situations where the daily average value may be

outside the established limit without this being a noncompliance

concern. The commenter requested that §63.1438(a)(1) be amended

to require that industry keep the daily average value within the

established limit "except as otherwise provided in this subpart."
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In addition, the commenter interpreted §63.1438(a)(1) to

mean that the owner or operator is allowed to operate with a

daily average parameter value "at or above" the minimum, or "at

or below" the maximum. Therefore, it was requested that

paragraph (a)(1) be revised to reflect this interpretation as

follows:

(1) The owner or operator shall operate control and

recovery devices such that the daily average value of monitored

parameters remains at or above the minimum established level, or

remains at or below the maximum established level, except as

otherwise provided in this subpart.

Response: The EPA agrees with the commenter, and has added

the language requested by the commenter to §63.1438(a)(1).

2.13.7 Method 1 or 1A

Comment: One commenter (IV-D-04) noted that §63.1426(c)(1)

requires the use of Method 1 or 1A of 40 CFR part 60, Appendix A,

as appropriate, to select sampling sites. However, the commenter

claimed that, in many instances, neither method would be

appropriate. Method 1 is only for pipes or stacks with a

diameter of 12 inches or more, and it cannot be used when flow is

cyclonic or swirling or when there is a flow disturbance within

specified distances from the sampling site. Method 1A can be

used for smaller diameter pipes, but is only for particulate

matter sampling. Therefore, the commenter concluded that neither

method will be appropriate for determining sampling sites.

Response: First, the rule was restructured by separating the

paragraph addressing the use of Method 1 or 1A for sample or

velocity traverses from the paragraphs specifying the sampling

site location. In other words, if the owner or operator conducts

a sample or velocity traverse, the final rule requires that

Method 1 or 1A be used. However, it does not require that these

methods be used to select sampling sites. Second, the EPA has
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decided to add text that states that references to particulate

matter in Method 1A do not apply for the purposes of subpart PPP. 

Because Method 1A can be used for smaller diameter pipes, it does

not have the problem that would exist if only Method 1 could be

used (since Method 1 is only for stacks or pipes that are greater

than 12 inches in diameter). By saying that "references to

particulate matter in Method 1A do not apply for the purposes of

this subpart," in §63.1426(c)(4)(i) of the final rule (test

method requirements), the EPA is making sure that owners and

operators can use Method 1A to select a sampling site.

2.13.8 Engineering Calculations as an Alternative Compliance

Demonstration to Performance Testing

Comment: Three commenters (IV-D-05, IV-D-07, IV-D-08)

stated that industry representatives are concerned with the

feasibility, accuracy, and safety of taking sample emissions from

process vents in batch unit operations. The commenters stated

that a performance test on these short duration, variable vents

is likely to be very inaccurate and potentially dangerous as

well. Therefore, Commenters IV-D-07 and IV-D-08 suggested that a

material balance based on common engineering calculations, which

the commenter felt would provide a more accurate, less costly,

and significantly safer means to verify compliance, should be

included in the final rule as a compliance demonstration option. 

Commenter IV-D-05 said engineering calculations or other

alternatives, such as pilot plant data or manufacturer’s

recommendations, should be permitted for compliance testing. 

Commenter IV-D-05 reasoned that otherwise, demonstration of

emission reduction efficiency based on testing will be extremely

burdensome to the owners or operators of PMPUs that are designed

for multi-product operation and that employ a batch process with

very short venting times (the most typical processes, according

to the commenter). Commenter IV-D-05 recommended revisions in

§63.1426 through §63.1428, §63.1431, and §63.1438 to clarify that
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these other alternatives are available to affected sources to

demonstrate compliance. 

Response: The EPA recognizes that there are issues related

to the feasibility, accuracy, and expense of testing process

vents from batch unit operations. The EPA would refer readers to

Section 7.3 of EPA’s “Control of Volatile Organic Compound

Emissions from Batch Processes - Alternative Control Techniques

Information Document” EPA-453/R-94-020 for a detailed discussion

of these issues. However, the EPA does believe that accurate

emission tests can be conducted for these process vents.

One reason that the EPA has historically required

performance testing for control devices that reduce emissions

from process vents, when engineering analyses is allowed for

other emission sources (such as storage vessels), is that

emissions from process vents are typically significantly larger

than those from other emission sources. When emissions are

larger, the EPA believes that it is important that the

effectiveness of the control device be accurately determined by a

performance test.

Given that the magnitude of the emissions was a part of the

basis for requiring performance tests, the EPA believes that it

is reasonable to allow an alternative to performance testing for

a process vent control device if emissions being routed to the

device are comparable to the emissions that would be vented to

control devices for other emission sources for which performance

tests are not required. Therefore, the EPA decided that

engineering assessments could be allowed in lieu of performance

testing for “small” control devices that reduce HAP emissions

from process vents. For the Pharmaceutical Production NESHAP,

the EPA also determined that it was appropriate to allow

engineering calculations as an alternative to performance testing

for small control devices, where a small control device is

defined as one with uncontrolled annual HAP emissions of less
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than 10 tons per year. The EPA believes that this level of

uncontrolled emissions is also appropriate to define a small

control device for the polyether polyols industry. Therefore,

the final rule allows the use of a design evaluation instead of a

performance test if the control device receives less than 10 tons

per year uncontrolled emissions from one or more PMPUs.

The exemption from performance testing for small control

devices discussed above should help to alleviate some of the

concerns raised by the commenters. Many of the concerns related

to the feasibility, accuracy, and expense of testing these batch

vents are due to the short duration, variable nature of batch

venting episodes. The EPA believes that if a control device

receives more than 10 tons per year of uncontrolled HAP

emissions, it is likely that the vent streams being routed to the

device are of longer duration and less variable, thus making it

easier to conduct the performance test.

However, the EPA also recognizes that the small control

device exemption will not totally eliminate the concerns raised

by the commenters. Therefore, the EPA made other changes to the

testing requirements to address potential problems related to the

testing of batch process vents, which are briefly discussed

below.

Since batch emission episodes can be less than one hour, the

rule was changed to specify that test runs be conducted for the

complete duration of the batch venting episode or one hour,

whichever is less. Other references to one-hour periods were

also removed.

The changes discussed in the previous comment relating to

the use of Method 1 or 1A to select sampling sites were also

made.

With regard to the safety issue, the final rule states that,

in cases where it is imperative to limit any leakage of emissions

into the work atmosphere, a sampling port with a double seal

should be installed so that the probe can be inserted and removed
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without any leakage of exhaust gas into the work atmosphere. 

Further, the final rule requires that permanent sampling ports be

installed at the inlet to the control device during a period when

it is most convenient (or least disruptive) to shut the process

down (e.g., during a scheduled maintenance outage). In addition

to these specific requirements, a general requirement was added

that allows owners or operators to eliminate potential testing

scenarios if the test could create a situation which could cause

plant or testing personnel to be subject to unsafe conditions.

In conclusion, the EPA acknowledges that issues exist with

regard to the testing of emissions from batch process units. 

Changes have been made to the final rule to address these issues. 

However, the Agency maintains that numerous other industries that

utilize batch processes are regulated by MACT standards, and are

able to conduct performance tests. The EPA believes that the

commenters did not provide sufficient rationale why the polyether

polyols industry presents unique testing problems that are not

present in these other industries that utilize batch processes. 

Therefore, the final rule requires that control devices that

receive more than 10 tons per year of uncontrolled organic HAP

emissions conduct tests to demonstrate control device

performance.

Comment: Commenter IV-D-07 requested that, at a minimum,

the EPA should provide better technical guidance before making

flow measurement mandatory for these variable, and potentially

high organic content, vent streams. The commenter stated that a

performance test on these short duration, variable vents is

likely to be very inaccurate and discussed the safety concerns as

well.

Response: The EPA feels that the technical guidance for

measuring flow measurements are sufficient, and did not provide

additional guidance in the final rule.
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2.13.9 Request for Exemption from Testing Multiple Similar

Controls

Comment: One commenter (IV-D-03) maintained that although

many of the facilities in the EPA’s polyether polyol database may

use a single control device for process vent emission control,

this is not necessarily true for all current or future

facilities. For example, the commenter’s facility operates

several separate control devices within a PMPU which have similar

designs and operating rates. They may also operate separate

PMPU’s which have similar control system designs and operating

rates. They requested that engineering calculations be permitted

in lieu of testing where it can be demonstrated that the process

vents are similar sources, and the commenter suggested adding

this exception to §63.1426(b) in the final rule.

Response: The EPA does allow engineering calculations in

the case of a control technique that receives less than 10 tons

per year uncontrolled emissions (see Section 2.12.8). However,

for control techniques receiving more than 10 tons per year of

HAP emissions, the EPA requires performance testing, regardless

of whether there are separate, similar control devices on-site. 

The EPA believes that the application of this cutoff, as well as

the allowances for direct measurement of condenser exhaust gas

temperature, have decreased the testing burden associated with

the rule and contends that such large control devices should be

tested.

2.13.10 Worst-Case Testing

Comment: Four commenters (IV-D-04, IV-D-05, IV-D-06 and IVD-08) expressed concern that the proposed rule requires that

performance tests for process vents be conducted during worstcase operating conditions for the process. The commenters

requested that this requirement be deleted from the rule for the

following reasons:
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1. Commenter IV-D-04 stated that there is no definition of

"worst-case" conditions for the process. The EPA has provided

criteria for determining worst-case emission episodes from batch

process vents, but no criteria for determining worst-case

operating conditions for the process. The commenter maintained

that owners or operators will have to guess what the phrase

means, and they will have inconsistent interpretations.

2. Two commenters (IV-D-04, IV-D-06) noted that many

companies have large, integrated manufacturing sites where a

control device may be shared by more than one process. In those

cases, the validity of the performance tests depends not so much

on the operating conditions of "the process" (the PMPU), but on

the operating conditions for the control device.

3. Commenter IV-D-06 explained that batch reactor vents to

the control device are typically at low flow rates and of short

duration, making testing of such derived "worst case" episodes

difficult, if not impossible. Commenter IV-D-08 added that these

measurements may be technically unfeasible.

4. Commenter IV-D-04 pointed out that other regulations for

continuous processes have allowed performance tests during

representative operating conditions, and there is no obvious

technological difference that would require a different approach

to performance testing in this rule.

5. Commenter IV-D-04 stated that performance tests always

have a deadline. The commenter was concerned that, if the

industry must achieve "worst-case operating conditions" for a

specific process during that deadline, then they would have to

change the production rate for the PMPU. This would cause

problems, because the production rate would otherwise be dictated

by demand for the product of that PMPU. Commenter IV-D-06 also

noted that, in batch operations, staging such a scenario would

result in additional manpower cost and the manufacturing of

products for which a market demand may not exist.
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6. Commenter IV-D-04 noted that, in most cases, the organic

HAP reduction efficiency of a control device is fairly stable

across a wide range of HAP concentrations. Since control devices

are designed to have some excess capacity, operating any single

process unit at its worst-case rate, rather than a representative

rate, would not be expected to make any significant difference in

the performance of the control device.

7. Two Commenters (IV-D-06 and IV-D-08) indicated that, due

to process design limitations, monitoring of these "worst-case"

scenarios could result in unsafe operating conditions. 

For these reasons, the commenters encouraged EPA to revise

§63.1437(a)(1) to delete the clause "except that performance

tests shall be conducted during worst case operating conditions

for the process."

Response: Worst-case testing requirements were not deleted

from the final rule, but were revised. The EPA’s reason for

requiring compliance testing under worst case conditions is so

that the reduction efficiency of the control device is documented

under the most challenging conditions for that control device,

especially since commenters noted how difficult it is to

represent a typical venting episode. The phrase "worst-case" in

the proposed rule referred to the operating conditions of the

process (or PMPU). The worst-case testing requirement has been

revised to require testing during the worst-case conditions with

respect to the combustion, recovery, or recapture (i.e., control)

device.

Presumably, the control device should function as well or

better under conditions that are not as challenging. By revising

the rule to require testing during the worst-case conditions with

respect to the control device, continuous monitoring of operating

parameters established during the test provides a reasonable

measure of continuous compliance with the efficiency requirement

under all conditions.
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The commenters asserted that there is no obvious

technological difference that would require a different approach

to performance testing in this rule as from other regulations

have allowed performance tests during representative operating

conditions. The EPA disagrees with the commenters’ rationale. 

The EPA believes that there are obvious technological differences

from the polyether polyols industry to industries previously

regulated (particularly SOCMI type industries) since polyether

polyols are produced on a batch basis. There is much more

variance in the process vent parameters (i.e., flow and

concentration) for process vent streams from batch unit

operations, compared to process vents from continuous unit

operations. In fact, this point was stressed by commenters. The

EPA believes that it is more appropriate to compare the

requirements of this rule with other rules that also regulate

industries that operate on a batch basis. For this rule the EPA

not only compared the worst-case testing conditions with other

rules regulating batch processes, but adopted similar language to

that which is used in the Pharmaceutical Production NESHAP (40

CFR 63, subpart GGG).

The EPA would like to clarify a misconception related to

these worst-case testing provisions. It is not the intent that

production schedules be significantly altered, or that

impractical scenarios be created for testing that would never

occur in actual production. In other words, the EPA intends that

testing be conducted for the worst-case situation that can

reasonably be expected to occur during normal production. In

order to clarify this intent, the EPA has added language in

§63.1438, the general testing section of the rule. This new

language specifies that absolute worst case testing conditions

does not include situations that could cause damage to equipment,

situations that necessitate that the owner or operator make

product that does not meet an existing specification for sale to
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a customer, or situations that necessitate that the owner or

operator make product in excess of demand. 

The added language in §63.1438 also specifies the time

period in which the worst-case conditions are to be determined. 

This time period is either the 6-month period that ends 2 months

before the Notification of Compliance Status is due, or the 6-

month period that begins 3 months before the performance test and

ends 3 months after the performance test. By limiting the worstcase conditions to one of these 6-month periods, the rule

eliminates the need for an owner or operator to consider endless

possible production scenarios, and allows them to focus on those

production scenarios in the 6-month period selected by the owner

or operator.

In conclusion, the EPA believes that requiring that

performance tests for process vents from batch unit operations

during absolute worst-case conditions is necessary to ensure that

the emission limitations in the rule are achieved. The EPA also

believes that, with the modifications to the rule made after

proposal, that the worst case provisions are reasonable and

workable for the polyether polyols industry.

Comment: One commenter (IV-D-04) maintained that if EPA

keeps the concept of "worst-case" scenarios, that the EPA should

clarify that a "simulated" scenario, as described in

§63.1426(c)(3)(i)(B)(4), involves modeling or calculations,

rather than actual production. It was suggested that someone

might interpret "simulated" to mean that industry must produce an

artificial worst-case scenario by actually running all its

production units at top capacity simultaneously, which would not

be practical. The commenter requested that EPA clarify this

point by adding a parenthetical phrase, "(i.e., modeling or

calculations)" to §63.1426(c)(3)(i)(B)(4). It was also suggested

that EPA clarify that "worst-case" is limited to the maximum

production allowed in a State or Federal permit or regulation.
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Response: The EPA agrees with the commenter that, at

proposal, the concept of "worst-case" scenarios was not clear.

The EPA has clarified the requirements in the final rule.

The EPA did not incorporate the specific language requested

by the commenter (i.e., modeling or calculations). However, the

EPA believes that the changes discussed in response to the

previous comment address the concerns raised by this commenter.

Finally, the commenter's suggestion that the EPA also

include language stating that "worst-case" is limited to what is

allowed under State or Federal rules or permits was included in

the final rule.

2.13.11 Determination of Emission Profile for Worst-Case

Testing

Comment: One commenter (IV-D-05) noted that

§63.1426(c)(3)(i)(C) allows "either process knowledge or test

data" to be used to determine the emission profile. The

commenter recommended that the section be changed to allow both

process knowledge and test data to be used. This paragraph also

allows previous test results only if the results are still

representative of current conditions. The commenter also

recommended that previous test results be allowed if they can

readily be adjusted to account for changes in conditions, which

will avoid unneeded, costly additional tests. Therefore, for

clarity, the commenter recommended that the text be revised

accordingly.

Response: Due to the total re-working of the worst-case

testing provisions discussed earlier, the paragraph cited by the

commenter does not exist in the final rule. Therefore, no

changes were made by the EPA in response to this comment.
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2.14 PARAMETRIC MONITORING

2.14.1 Operating Permit Requirements

Comment: One commenter (IV-D-05) maintained that the

information in §63.1438(a)(2) is too detailed to be included in

an operating permit and recommended revising the text to delete

"or operating permit" as follows: 

"As specified in §63.1439(e)(6), all established

levels, along with their supporting documentation and the

definition of an operating day, shall be submitted as part

of the Notification of Compliance Status. Once approved,

this information shall be incorporated into the affected

source’s Notification of Compliance Status or operating

permit."

Response: The EPA has decided to remove the entire last

sentence of this paragraph because it is redundant and

unnecessary.

2.14.2 Average versus Maximum Value for Monitoring

Comment: One commenter (IV-D-05) maintained that the

mandatory parameter limit should not be set at the "average"

minimum (or maximum, where appropriate) value from the three test

runs. According to the commenter, using an average takes away

some legitimate leeway to use a broader parameter range for which

compliance has been demonstrated. Therefore, the commenter

recommended revising the text in §63.1438(b)(2) as follows:

(2) Process vents from continuous unit operations. During

initial compliance testing, the appropriate parameter shall be

continuously monitored during the required 1-hour runs for

process vents from continuous unit operations. The maximum (or

minimum) monitoring levels(s) shall then be established as the

average of based on the maximum (or minimum) point value from the

three one-hour test runs. The average of the maximum values

shall be used when establishing a maximum level, and the average

of the minimum values shall be used when establishing a minimum

level.

Response: The EPA does not agree with this comment. The EPA

has reevaluated the parametric monitoring for this rule, as well
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as other recent NESHAP (namely the Pharmaceutical NESHAP) and has

determined that the operating parameter level must be established

as the average of the maximum (or minimum) point values obtained

during the three one-hour (continuously monitored) test runs. 

However, if the owner or operator wishes to adjust the parametric

levels established during the test runs because the test results

indicated a higher control efficiency than is required by the

regulation, then the owner or operator has this option. 

Specifically, provisions in §63.1438(c) and (d) allow the

parametric monitoring levels to be adjusted based on engineering

assessments. 

2.14.3 Compliance Determination

Comment: Two commenters (IV-D-04 and IV-D-05) requested

that the EPA clarify the appropriate use of parameter monitoring

data for enforcement purposes. Commenter IV-D-04 noted that the

provisions of paragraph 63.1428(h), which require parameter

monitoring data to be used to demonstrate continuous compliance

with the emission limit, are inaccurate and unnecessary. 

Commenter IV-D-05 had similar concerns regarding §63.1427(h). 

The commenters stated that parameters such as temperatures or pH

readings are only surrogates that indicate proper operation of a

control device. They do not prove compliance or noncompliance

with an emission standard because they do not measure emissions

or emission reductions.

Commenter IV-D-04 claimed that the EPA had a more valid

enforcement tool available in §63.1438(a)(1) which requires

industry to keep the daily average value of monitored parameters

within the approved limit. The commenter recommended that the

EPA revise §63.1427(h) to state that parameter monitoring data

will be used "to demonstrate continuous compliance with

§63.1438(a)(1)." The commenter concluded that EPA could then

assess exactly the same penalties, while maintaining a connection

with fact.
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Commenter IV-D-05 stated that the rule should have a

requirement to keep the parameter data within a specified range

or limit, and excursions (appropriately defined) should, if not

excused, be violations of that operating requirement. Therefore,

the commenter recommended revising the text in §63.1427(h), as

follows:

(h) ECO Monitoring Requirements. The owner or

operator using ECO shall comply with the monitoring

requirements of this paragraph to demonstrate continuous

compliance with the emission limitation §63.1438(a)(1). 

Paragraphs (h)(1) through (h)(3) address monitoring of the

ECO.

Similarly, Commenter IV-D-05 also recommended that the text

in §63.1438(e)(1) be revised to add the reference for determining

compliance, by inserting the phrase "with §63.1438(a)(1)" after

the word "compliance." The commenter also requested that

§63.1438(e)(2) be revised to add appropriate references as

follows:

"Except as provided in paragraphs (e)(3) and (g) of this

section, for each excursion, as defined in paragraphs (e)(3) and

(f) of this section, the owner or operator shall be deemed out of

compliance with the provisions of this subpart §63.1438(a)(1)."

Response: First, the EPA agrees that the proposed language

in §63.1429(h) regarding compliance with the emission limitation

was not appropriate. However, the EPA does not believe that the

specific reference to §63.1438(a)(1) is appropriate in either

§63.1427(h) (Note: the proposed §63.1427(h) is §63.1427(i) in the

final rule) or §63.1438(e)(1).

Paragraph §63.1438(a)(1) requires the owner or operator to

operate combustion, recovery, and recapture devices so that the

daily average value of monitored parameters remains at or above

the minimum established parameter level, or remains at or below

the maximum established monitoring level.
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The EPA maintains that the requirement to maintain the daily

average monitored parameter within the established limit is only

one aspect of compliance with the monitoring provisions of

subpart PPP. In order to comply with the monitoring

requirements, the owner or operator must accomplish a number of

activities, from the installation of proper monitoring equipment

to the establishment of parameter monitoring levels, to the

proper operation of the combustion, recovery, or recapture device

and monitoring equipment.

For ECO, the owner or operator has similar requirements from

the establishment of parameter monitoring levels to ensuring that

each batch is accomplished in accordance with the established

levels. Therefore, the EPA revised what used to be §63.1427(h)

in the proposed rule and is §63.1427(i) in the final rule, to

state that owners or operators using ECO “shall comply with the

monitoring requirements of this paragraph to demonstrate

continuous compliance with this subpart . . . “

While the EPA disagrees with the commenter that the

relationship between compliance and paragraph §63.1438(a)(1), the

EPA agrees with the argument that exceedances of operating

parameters should not be classified as violations of the emission

standard. 

To assure that control devices used by the owner or operator

are properly operated and maintained so that continued compliance

with the applicable requirements is accomplished, the EPA has

adopted the approach in part 63 standards that monitoring be used

as a method for directly determining continuous compliance with

the applicable requirements. Further, the Agency is committed to

following this approach whenever appropriate in future

rulemakings. 

When determining appropriate monitoring options, the EPA

considers the availability and feasibility of the following

monitoring strategies in a “top-down” fashion: (1) Continuous

emission monitors (CEMs) for the actual HAP emitted, (2) CEMS for
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HAP surrogates, (3) monitoring operating parameters, and (4) work

practice standards. In this standard, monitoring of control

device operating parameters is considered appropriate for all

emission sources. However, the EPA has allowed the option of the

continuous monitoring of organic compounds, which could mean

monitoring of the actual organic HAP or an organic surrogate.

The EPA believes that if organic compounds are monitored,

exceedance of the established value represents a violation of the

emission limitation. Similarly, because the exit gas temperature

of a condenser is so closely correlated with emissions, the EPA

believes that an exceedance of the established condenser

temperature should also represent a violation of the emission

limit. The EPA agrees with the commenters that exceedance of

other monitoring parameters is not necessarily an exceedance of

an emission limit.

Paragraph §63.1438(e) of the final rule has been rewritten

to add specificity regarding what the owner or operator is out of

compliance with when an excursion occurs (that is not an excused

excursion). If an organic monitoring device is used to monitor

HAP or TOC concentration at the outlet of a recovery or recapture

device, the final rule clarifies that each excursion where the

daily average value of monitored parameters is above the maximum,

or below the minimum established parameter level, represents a

violation of the emission limit. Similarly, an excursion where

the daily average temperature is above the maximum established

temperature for a condenser represents a violation of the

emission limit. Other excursions where average values are above

the maximum, or below the minimum established parameters

represent violations of the operating limit, rather than

violations of the emission limit. Also, excursions due to

insufficient monitoring data are violations of the operating

limit.
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2.14.4 Excursion Provisions for Storage Vessels Exempt from

Continuous Monitoring, Process Vents from Batch Unit

Operations, and Extended Cookout

Comment: One commenter (IV-D-04) suggested that EPA add

provisions in §63.1438 for storage vessels that are not required

to conduct continuous monitoring. The commenter noted that not

all storage vessels are required to conduct continuous

monitoring. The PEPO standard requires a monitoring plan, which

must specify what will be monitored and how often. For example,

some storage vessels may be monitored only while they are being

filled, which could be for 2 hours. Consequently, the concept of

a "daily average" parameter value will not apply to those storage

vessels. Also, in some cases the monitored value may not be for

a "parameter," in the strict sense of the word. The commenter

noted that because of the significant differences in emission

patterns and controls among different storage vessels, MACT

standards do not specify a "one size fits all" approach to

monitoring. Therefore, there cannot be a "one size fits all"

definition of "excursion," even though §63.1438(f) attempts to do

just that. Section 63.1438(f) combines all storage vessels with

process vents and says the daily average is the measure of

compliance for all of them, which will not work. The commenter

recommended that the EPA revise §63.1438(f) so that it refers

only to storage vessels required to conduct continuous

monitoring. Also, it was recommended that the EPA add a new

paragraph "(h)" with appropriate excursion definitions for

storage vessels that are not required to conduct continuous

monitoring. 

Response: The EPA agrees with the commenter that separate

monitoring requirements should be established for storage vessels

that are required to be continuously monitored and for storage

vessels that are not required to be continuously monitored. 

However, instead of adding a new paragraph as §63.1438(h), the
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EPA has renumbered §63.1438(f) so that the proposed language is

now (f)(1) and the new paragraph is §63.1438(f)(2). A

parenthetical has been added in §63.1438(f)(1) to clarify that

the provisions apply to storage vessels where the applicable

monitoring plan specifies continuous monitoring.

In addition, consideration of this comment caused the EPA to

realize that the proposed excursion definitions related to

insufficient monitoring data in §63.1438(f)(2), (f)(3), and

(f)(4) were not always suitable for process vents from batch unit

operations. For these batch process vents, venting episodes may

be less than one hour, which makes the “valid hour of data”

concept unworkable. Clearly the EPA did not intend that an

excursion occur when the entire emission episode is controlled

and monitored in accordance with the rule, but the episode is

less than one hour. Therefore, paragraph §63.1438(f)(3) was

added to address excursions for process vents from batch unit

operations.

Also, excursions were defined in the proposed §63.1427(h)(3)

for owners or operators using ECO to comply with the epoxide

emission limitations in §63.1425(b). The EPA determined that a

reference to those excursion definitions was needed in the

parameter monitoring levels and excursions section (§63.1438). 

Therefore, paragraph §63.1438(f)(4) was added referring to the

excursion definitions for ECO in §63.1427(h)(3).

2.14.5 Continuous Monitoring

Comment: One commenter (IV-D-04) strongly supported 

§63.1438(e) and (f) of the proposed rule. However, proposed

§63.1438(e) stated that its subparagraphs only applied to

emission points and control or recovery devices for which

continuous monitoring was required, and the commenter requested

that EPA revise §63.1438(e)(3) so that it would apply regardless

of whether continuous monitoring was required. Paragraph

§63.1438(e)(3) lists the situations in which no excursion is
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considered to have occurred, even though parameters strayed

outside of their limits, or data were not collected. According

to the commenter, these situations are universal; they apply to

any emission point or control or recovery device, regardless of

whether continuous monitoring is required. The commenter stated

that the equivalent paragraph in the HON (§63.152(c)(2)(ii)(E))

was specifically revised for the same reasons as those cited

above. The commenter recommended the following revision to

§63.1438(e):

"(e) Compliance determinations. The provisions of this

paragraph, except (e)(3) of this paragraph, apply only to

emission points and control or recovery devices for which

continuous monitoring is required under this subpart."

Response: The EPA is in general agreement with the concepts

raised by the commenter. However, the EPA decided to more

significantly alter the structure of §63.1438(e) and (f), as

described below. In the final rule, §63.1438(e) describes

“violations” to the rule. As discussed in response to an earlier

comment (2.14.3), §63.1438(e) has been revised to address the

relationship between excursions and violations.

The EPA has made changes to §63.1438(f) to more clearly

provide all of the necessary information about the definition of

excursions. First, as discussed above in response to comment in

section 2.14.4, excursion definitions were added for storage

vessels where the applicable monitoring plan does not specify

continuous monitoring, for batch process vents, and for ECO.

Basically, there are two ways an excursion can occur. The

first is if the average parameter value measured is above a

maximum, or below a minimum, established value. The second is if

insufficient monitoring data are collected. The final rule makes

clarifications of the data to be used in both of these

circumstances.
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With regard to calculating averages, §63.1439(d)(7) of the

final rule specifies that monitoring data collected during

periods of monitoring system breakdowns, repairs, calibration

checks, and zero (low-level) and high-level adjustments; startups; shutdowns; malfunctions; and periods of non-operation of the

affected source that result in the cessation of emissions to

which the monitoring applies are not to be included when

calculating any average.

Language has also been added to §63.1438(f) to clarify when

monitoring data are insufficient. An excursion due to

insufficient monitoring data occurs if measured values are

unavailable for a specified percentage of time the control device

is in operation. First, the rule now clarifies the situations

that cause measured values to be unavailable: monitoring system

breakdowns, repairs, calibration checks, or zero (low-level) and

high-level adjustments. Second, the final rule clarifies that

periods of start-ups; shutdowns; malfunctions; and periods of

non-operation of the affected source that result in the cessation

of emissions to which the monitoring applies are not to be

included in defining the period of control device operation. 

The EPA believes that the clarifications discussed above address

the commenter’s concern over the provisions of the proposed

§63.1438(e)(3) applying to all situations, whether or not

continuous monitoring is required.

2.14.6 Clarification to Text

Comment: One commenter (IV-D-05) recommended, for clarity,

that the text in §63.1438(c) be revised as follows:

"Establishment of parameter monitoring levels based on

performance tests, supplemented by engineering assessments,

and/or manufacturer’s recommendations. Parameter monitoring

levels established under this paragraph shall be based on the

parameter values measured during the performance tests

supplemented by engineering assessments and/or manufacturer’s

recommendations...."
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Response: The EPA agrees with the commenter, and has made

the suggested change in the final rule.

2.15 GENERAL RECORDKEEPING AND REPORTING

2.15.1 Elimination of Initial Notification

Comment: One commenter (IV-D-05) stated that the Initial

Notification in §63.1439(e)(3) should not be required, in order

to reduce the regulatory burden, and to be consistent with the

Polymers and Resins MACT. The commenter recommended that

§63.1439(e)(3) be deleted, the subsequent sections renumbered

accordingly, and that the reporting cross-reference in Table 5 be

modified. In addition, the commenter recommended that

§63.1432(n) and §63.1434(d) be changed accordingly.

Response: The Agency’s enforcement personnel and the State

representatives involved in this regulatory process consider the

Initial Notification requirement in §63.1439(e)(3) a necessary

tool for enforcement and compliance purposes. Moreover,

completion of the Initial Notification should not take more than

a few hours, since the information requested is very basic; i.e.,

the name and address of the owner or operator; the address

(physical location) of the affected source; an identification of

the emission points and affected source; and an identification of

whether the affected source can achieve compliance by the

relevant compliance date. Therefore, the Agency has not made any

of the requested changes. 

2.15.2 Provide Examples of Emission Points

Comment: One commenter (IV-D-05) maintained that the

addition of some examples in §63.1439(e)(3)(i)(C) of the "kinds"

of emission points to be identified in the Initial Notification

would be helpful.
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Response: The emission points subject to this rule and

required to be identified in the Initial Notification include the

emission points and equipment specified in the definition of

affected source under §63.1420(a). Section 63.1420(c) of the

rule describes emission points not subject to the provisions of

this rule. Since other provisions of the rule describe the

emission points to be regulated, the Agency does not believe it

is necessary to provide examples of emission points to be

identified in the Initial Notification in §63.1439(e)(3)(i)(C).

2.15.3 Periodic Report

Comment: One commenter (IV-D-05) noted that §63.1434(f)

should say the Periodic Reports under subpart H "may" (rather

than "shall") be submitted with the Periodic Reports under this

rule.

Response: The Agency agrees that the owner or operator has

the option to submit the Periodic Reports for equipment leaks as

specified in subpart H at the same time as the Periodic Report

for this subpart or at another time. The final rule has been

changed accordingly.

2.15.4 Include all Records in One Section

Comment: One commenter (IV-D-05) recommended that in order

to make the recordkeeping and reporting section (§63.1439) and

Table 5 in the proposed rule as useful as possible, the EPA

should include all relevant requirements in §63.1439. For

example, the ECO recordkeeping requirements are in §63.1427(i)

and the reporting requirements are in §63.1427(j), but neither

citation appears in Table 5 or in §63.1439. The commenter

maintained that with a rule as complex as this, it is especially

important that all of the monitoring, recordkeeping, and

reporting requirements be included in a single section to ensure

that inadvertent non-compliance through failure to prepare a
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report or maintain a record that is not included in the

"Recordkeeping" section or table does not occur. 

Another commenter (IV-D-04) was also concerned that the

recordkeeping and reporting requirements were scattered

throughout the proposed rule, plus various recordkeeping and

reporting requirements from the General Provisions. The

commenter believed that this approach is very likely to cause

inadvertent noncompliance. The commenter recommended that all

recordkeeping and reporting requirements be in one place in the

rule. Alternatively, if that cannot be done, the commenter

requested that EPA include every recordkeeping and reporting

requirement in a single table, with the specific citation to

where that requirement is found.

Response: The Agency believes it is more logical to include

the specific recordkeeping and reporting requirements related to

each emission source type in the applicable sections of the rule

because not all facilities have every source type. Therefore,

the suggestion to include all recordkeeping and reporting

requirements in one place has not been adopted. The Agency,

however, has added a table in the final rule for all routine

recordkeeping and reporting requirements, including the specific

citation in the rule for the requirement, and the due date for

the specific report as recommended (as Table 7 of the final

rule). The Agency believes that this table will be useful to

owners and operators of affected sources in complying with the

various reporting requirements of the rule.

2.15.5 Parametric Monitoring During Periods of Start-up,

Shutdown or Malfunction

Comment: Three commenters (IV-D-05, IV-D-07 and IV-D-09)

provided revised language for §63.1438(e)(3) regarding monitoring

during periods of start-up, shutdown, and malfunction (SSM).
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One commenter (IV-D-05) maintained that the provisions of

§63.1438(e)(3) do not quite follow the revised HON, and that the

differences cause problems. For example, the proposed rule text

literally says there is no excursion "if the daily average value

of a monitored parameter is above the maximum level or below the

minimum level established." In other words, there can never be

an excursion. This comes about from adding a comma after the

word "established" (which was not in the HON). Also, this

paragraph (unlike the HON) does not discuss monitoring data

collected during start-ups and shutdowns. To be consistent with

the HON, Commenter IV-D-05 recommended deleting the proposed text

in §63.1438(e)(3) and replacing it with the following:

(3) If a monitored parameter is outside its

established range or monitoring data are not collected

during periods of start-up, shutdown, or malfunction (and

the source is operated during such periods in accordance

with the source’s start-up, shutdown, and malfunction plan

as required by §63.6(e)(3) of subpart A), or during periods

of non-operation of the PMPU portion thereof (resulting in

cessation of the emissions to which the monitoring applies),

then the excursion is not a violation and, in cases where

continuous monitoring is required, the excursion does not

count toward the number of excused excursions for

determining compliance.

Another commenter (Commenter IV-D-07) maintained that

monitoring records from periods of SSM would not be expected to

provide additional information as to whether plans are followed

in many cases, nor would they provide the Agency with information

regarding the adequacy of the plans. Commenter IV-D-07 provided

a few examples to support this claim. Commenter IV-D-07 stated

that the proposed rule simply requires that the source collect

data for periods when it is not required to comply with the

standard resulting in a potential noncompliance status (for not

collecting data), with essentially no benefit to the environment. 

The commenter recommended that this position be dropped in the

final rule and that §63.1438(e)(3) of the final rule be revised

to conform with the HON as follows:
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(3) If the daily average value of a monitored

parameter is above the maximum level or below the minimum

level established, or if monitoring data cannot be collected

during monitoring device calibration check or monitoring

device malfunction, or if monitoring data are not collected

during periods of start-up, shutdown, or malfunction, or if

monitoring data are not collected during periods of nonoperation of the affected source or portion thereof

(resulting in cessation of the emissions to which the

monitoring applies), but the affected source is operated

during the period of start-up, shutdown, or malfunction in

accordance with the affected source’s Start-up, Shutdown,

and Malfunction Plan, then the event shall not be considered

a monitoring parameter excursion. 

Response: As discussed in section 2.14, the EPA made

significant revisions to paragraphs §63.1438(e) and (f). The

paragraph cited by the commenters no longer exists in the final

rule. However, the EPA believes that most of the concerns raised

by the commenters are addressed in the final rule.

First, §63.1439(d)(7) of the final rule specifies that

monitoring data collected during periods of monitoring system

breakdowns, repairs, calibration checks, and zero (low-level) and

high-level adjustments; start-ups; shutdowns; malfunctions; and

periods of non-operation of the affected source that result in

the cessation of emissions to which the monitoring applies are

not to be included when calculating any average. This paragraph,

which was in the proposed rule, clearly states that monitoring

data collected during start-ups, shutdowns, malfunctions, are not

to be included in an average. Therefore, the EPA believes that

it is unnecessary to additionally state that the exceedance of an

average value due to data collected during a start-up, shutdown,

or malfunction is not an excursion, when the data collected

should not be used to calculate an average.

Also, the EPA has added paragraphs §63.1438(f)(1)(v)(A)

through (D) and §63.1438(f)(2)(i)(B), which describe the periods

that are not to be included when determining the period of

combustion, recovery, or recapture device operation for the
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purpose of determining whether an excursion has occurred due to

insufficient monitoring data. Under these paragraphs, the

periods that should be left out when determining the period of

combustion, recovery, or recapture device operation include

start-ups; shutdowns; malfunctions; and periods of non-operation

of the affected source that result in the cessation of emissions

to which the monitoring applies.

The EPA does not agree with Commenter IV-D-07's opinion that

monitoring during start-ups, shutdowns, and malfunctions results

in “essentially no benefit to the environment.” It is the EPA's

position that requiring monitoring during these periods will

provide the EPA with more information concerning whether or not

Start-up, Shutdown, and Malfunction Plans were followed, and will

provide the EPA with valuable information for assessing the

adequacy of a source's Start-up, Shutdown, and Malfunction Plan

for future situations. Therefore, the final rule continues to

require that monitoring data be collected during periods of SSM.

Comment: One commenter (IV-D-04) maintained that EPA should

not impose a blanket requirement to monitor during start-ups,

shutdowns and malfunctions. There should be exceptions to this

requirement. For example, the industry cannot keep monitoring if

the monitoring device itself has the malfunction. Similarly, it

may sometimes be necessary to "valve off" a monitoring device

(isolate the device from the monitored stream) in order to keep

the device from being damaged. The commenter requested adding a

new paragraph, §63.1438(e)(4), to address these instances: 

(4) Failure to collect monitoring data shall not be

considered an excursion during periods of monitoring system

malfunction, or when the monitoring system must be isolated

or otherwise rendered nonoperational in order to prevent

damage to the monitoring system.

Also, the commenter recommended that EPA clarify that

parameter data gathered during start-ups, shutdowns and

malfunctions are excluded from daily averages for the purpose of
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determining excursions and referred to another commenter’s (IV-D05) suggested revisions to §63.1438(e)(3) to address this.

In addition, the commenter noted that although the rule,

§63.1438(e)(3), is clear that once a shutdown is complete and

emissions have ceased, monitoring is not required during the

ensuing period of non-operation, the preamble was not clear and

asked that EPA reaffirm this point. 

Further, Commenter (IV-D-09) stated that during the General

Provisions litigation, they discussed reasons for needing the

provisions for start-up, shutdown, and malfunctions and why

modifications were needed. They stated that EPA has agreed to

revised language; e.g., depending on flow, concentration, etc., a

control device may need to be diverted during start-up, shutdown,

or malfunction to prevent explosions, etc. and requested that

this language be incorporated into the Polyether Polyols MACT.

Response: The EPA is in general agreement with commenters

IV-D-04 and IV-D-09 on these points. As discussed in the

previous response, the changes to §63.1438(f) and §63.1439(d)(7)

clarify that parameter monitoring data gathered during start-ups,

shutdowns, malfunctions, and periods of non-operation of the

affected source resulting in cessation of the emissions to which

the monitoring applies, are to be excluded from daily averages,

and, in fact, all averages computed under subpart PPP or the

subparts that it references.

In addition, changes to §63.1439(b)(1) allow owners and

operators to “cease” collecting monitoring data from a particular

monitor (e.g., by shutting off the monitor, or diverting flow

away from it) during a start-up, shutdown, or malfunction if the

owner or operator can show that the monitor would be damaged or

destroyed as a result of the start-up, shutdown, or malfunction. 

This provision should satisfy the concerns expressed by

commenters IV-D-04 and IV-D-09. Such a provision must be

included in the Start-up, Shutdown, and Malfunction Plan. 
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Getting such a provision in the Start-up, Shutdown, and

Malfunction Plan requires is accomplished by submitting a

request, and rationale defending the request, in the

Precompliance Report or in a supplement to the Precompliance

Report, as described in the new language in §63.1439(e)(4). If

the request is not denied by the Administrator within 45 days

after receiving the request, it can then be incorporated into the

Start-up, Shutdown, Malfunction Plan. 

These changes are meant to strike a balance between the

EPA's concern that monitoring data are collected at all relevant

times and industry's concern that valuable monitoring equipment

could be damaged during a start-up, shutdown, or malfunction. 

The changes are intended to provide protection for monitoring

equipment during those periods, while providing the EPA with

assurance that monitoring equipment is not being "shut off"

indiscriminately.

Comment: One commenter (IV-D-05) maintained that

§63.1439(b)(1)(i)(C), which pertains to continuous monitoring

systems records of calibration checks, was not part of the Startup, Shutdown, and Malfunction plan and should be deleted. 

Response: The Agency has not deleted §63.1439(b)(1)(i)(C),

as requested by the commenter; however, the regulatory text in

that paragraph has been moved to §63.1439(d)(8), because the

Agency agrees that it is more of a global recordkeeping

requirement than a record specifically associated with the Startup, Shutdown, Malfunction Plan.

2.15.6 Exclusion of Monitoring Data from Daily Averaging

Comment: Three commenters (IV-D-02, IV-D-04, IV-D-05)

claimed that §63.1439(d) should include other situations where

monitoring data should not be included in the daily average

recorded. For example, data collected during start-ups,
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shutdowns, malfunctions, and periods of non-operation (of the

affected source or a portion thereof), resulting in cessation of

the emissions to which the monitoring applies. Commenter IV-D-04

also mentioned "data collected during calibration checks" as

another example. According to the commenters, these concepts are

captured in the HON, which has a revised paragraph structure for

greater clarity. Commenter IV-D-05 recommended, for consistency

with the HON, that proposed §63.1439(d)(7) be replaced with the

revised wording:

"Monitoring data recorded during periods of monitoring

system breakdowns, repairs, calibration checks, and zero

(low-level) and high-level adjustments identified in

paragraphs (d)(7)(i) through (d)(7)(v) of this section shall

not be included in any average computed under this subpart. 

Records shall be kept of the times and durations of all such

periods and any other periods during process or combustion,

recovery, or recapture control device operation when

monitors are not operating.

(i) Monitoring system breakdowns, repairs, calibration

checks, and zero (low-level) and high-level adjustments;

(ii) Start-ups

(iii) Shutdowns;

(iv) Malfunctions;

(v) Periods of non-operation of the PMPU (or portion

thereof), resulting in cessation of the emissions to which

the monitoring applies.

Commenter IV-D-04 supported the revised wording. 

Response: For consistency with decisions made on other

rules [e.g., the HON, §63.152(c)(2)(ii)(C)], the Agency has

revised §63.1439(d)(7) as suggested by the commenters to clarify

that data recorded during periods of start-up, shutdown,

malfunction, etc. should not be included in averages of monitored

data, including daily averages.

2.15.7 Retention of Superseded Start-up, Shutdown, and

Malfunction Plan

Comment: One commenter (IV-D-05) stated that §63.1439(b)(1)

does not say how long a superseded start-up, shutdown, and
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malfunction plan must be retained. To be consistent with the HON

provisions, the commenter recommended revising the text in

paragraph (b)(1) to add the following sentence after the fourth

sentence:

"... In addition, if the start-up, shutdown, and malfunction

plan is revised, the owner or operator shall keep previous

(i.e., superseded) versions of the start-up, shutdown, and

malfunction plan for a period of 5 years after each revision

to the plan...."

Response: For purposes of clarification and consistency,

the Agency has added the commenter’s suggested language into

§63.1439(b)(1) of the final rule.

 

2.15.8 Exclusion to Continuous Recordkeeping Requirements

Comment: Two commenters (IV-D-04 and IV-D-05) stated that

§63.1439(d) says that anyone subject to §63.1438 is required to

keep continuous records, which may not be true. For example, the

owner or operator of a storage vessel (closed-vented to a control

device) may be subject to §63.1438 (required to establish

parameter levels for the control device) but not be required to

keep continuous records. According to one commenter (IV-D-04),

the monitoring plan will specify the type and frequency of

required monitoring. Therefore, the commenters suggested

revising the text in §63.1439(d) to delete the words "required to

comply with §63.1438 and, therefore," in paragraph (d).

 

Response: The EPA agrees that continuous record keeping is

not required for all emission points, and the EPA has revised

§63.1439(d) accordingly.

2.15.9 Delete Redundancy in Recordkeeping Requirements

Comment: One commenter (IV-D-05) maintained that the source

should not be required to retain records if the daily average

value is within the limits and, therefore, the commenter
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recommended deleting paragraph §63.1439(d)(5). Another commenter

(IV-D-04) requested that EPA delete paragraphs §63.1439(d)(4) and

(d)(5), which describe records to keep when there are excursions

and when there are not excursions, respectively. According to

the commenter, they both require exactly the same records. Since

there is no difference, and since other portions of the rule

already require a record of this information, the commenter

maintained that paragraphs (d)(4) and (d)(5) serve no purpose and

should be deleted.

Response: The EPA agrees with Commenter IV-D-04 that

§63.1439(d)(4) and (5) are redundant with other portions of the

rule that already require a record of this information. 

Therefore, §63.1439(d)(4) and (5) have been “reserved” in the

final rule.

2.15.10 Recordkeeping Waiver

Comment: One commenter (IV-D-04) claimed that paragraph

§63.1439(d)(9) is inappropriate and should be deleted. It

requires that records be kept if industry has obtained a waiver

of recordkeeping requirements, which defeats the purpose of

having a waiver of recordkeeping requirements. The commenter

referred to the General Provisions, subpart A, §63.10(f) (on

which paragraph §63.1439(d)(9) relies), which allows a waiver in

any of three circumstances. The commenter maintained that

§63.10(f)(5) of subpart A, which provides that a waiver may be

conditioned on other recordkeeping or reporting requirements

deemed necessary by the Administrator, already provides for any

necessary records, and, therefore, paragraph (d)(9) is

unnecessary.

Response: The EPA disagrees that §63.1439(d)(9) is

unnecessary, but has revised §63.1439(d)(9) to be consistent with

§63.10(f)(5). This change is being made as a further measure to
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reduce the recordkeeping burden imposed by subpart PPP on owners

and operators, by overriding, in Table 1 of subpart PPP,

§63.10(b)(2) (§63.10(b)(2)(xii) requires the information that was

required in the proposed version of §63.1439(d)(9)). In the

final rule, §63.1439(d)(9) reads as follows:

(9) The owner or operator of an affected source

granted a waiver of recordkeeping or reporting requirements

under the General Provisions’ recordkeeping and reporting

requirements in §63.10(f) shall maintain the information, if

any, specified by the Administrator as a condition of the 

demonstrating whether an affected source is meeting the

requirements for a waiver of recordkeeping or reporting

requirements.

2.15.11 "Document on Demand"

Comment: One commenter (IV-D-05) referred to §63.1439(d)(8)

which says exempt flexible operation units must "maintain the

documentation" required by §63.1420(e)(7). The commenter

recommended that this provision be revised to include an option

that does not involve constantly maintaining documentation of the

unit’s exempt status (i.e., allowing the "document on demand"

option) and provided the following recommended revised wording:

(8) For each flexible operation unit in which the

primary product is determined to be something other than a

polyether polyol product, the owner or operator shall either

maintain the documentation specified in §63.1420(e)(7) or be

able to document upon request that the primary product is

not a polyether polyol." 

Response: The EPA agrees and the final rule allows the

owner or operator the option of providing documentation on

demand, showing that the primary product of a flexible operation

unit is not a polyether polyol. Therefore, the proposed

requirement under §63.1439(d)(8), referred to by the commenter,

has been deleted, and §63.1420(e)(8) now allows the owner or

operator of a flexible operation unit with something other than a

polyether polyol as its primary product to maintain documentation

of that fact or produce documentation on demand.
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2.15.12 Notification of Compliance Status

Comment: One commenter (IV-D-05) referred to

§63.1439(e)(5)(i) which says to include any other information

"required to be included" in the Notification of Compliance

Status (NOCS) under a variety of HON sections. The commenter

requested that EPA provide a list of the specific data this

section requires.

Response: The EPA appreciates the comment. However, the EPA

provides different compliance choices, and it would be lengthy

and confusing to describe every bit of information for every

compliance option in subpart PPP. For example, §63.1439(e)(5)(i)

references §63.1422(j) of this rule, which provides for overlap

with other regulations for monitoring, recordkeeping, or

reporting with respect to combustion devices, recovery devices,

or recapture devices. Under these overlap provisions, the owner

or operator has compliance choices, but he must notify the

Administrator of his choice in the NOCS required by

§63.1439(e)(5). 

In addition to specific information required in

§63.1439(e)(5)(i), this section requires "any other information

required to be included" in the NOCS under other sections, as

applicable. If any information in the referenced provisions is

applicable, then that information must also be included, as

appropriate. Therefore, the owner or operator of an affected

source must review the referenced provisions and submit any

information that is required to be reported in the NOCS, as

applicable.

2.15.13 Addition of a Provision for Reporting Updates

Comment: Two commenters (IV-D-04 and IV-D-05) stated that

throughout the proposed rule, there are various places where the

EPA says certain information must be submitted in a specific

(named) one-time report. However, there are circumstances where
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the same type of information may need to be submitted later. For

example, there may be changes to the process, or additional

emission points, etc., which could justify either a new report,

or an update to a previous report. The commenter requested that

EPA add a provision that specifies how and when to report such

information. Commenter (IV-D-05) provided suggested language.

Response: The Agency has considered these comments and

agrees that there will be circumstances where certain information

already reported may need to be supplemented or updated.

Therefore, in order to allow the submittal of such information,

the Agency has amended paragraphs 63.1439(e), (e)(1), and (e)(4)

as follows:

(e) Reporting and notification. (1) In addition to

the reports and notifications required by 40 CFR part 63,

subpart subparts A and H of this part, as specified in this

subpart, the owner or operator of an affected source shall

prepare and submit the reports listed in paragraphs (e)(3)

through (e)(9)(8) of this section, as applicable. All

reports required by this subpart, and the schedule for their

submittal, are listed in Table 8 of this subpart.

(1) Violation of reporting requirements. Owners and

operators shall not be in violation of the reporting

requirements of this paragraph (e) for failing to submit

information required to be included in a specified report if

the owner or operator meets the requirements in paragraphs

(e)(1)(i) through (iii) of this section. Examples of

circumstances where this paragraph may apply include

information related to newly-added equipment or emission

points, changes in the process, changes in equipment

required or utilized for compliance with the requirements of

this subpart, or changes in methods or equipment for

monitoring, recordkeeping, or reporting.

(i) The information was not known in time for

inclusion in the report specified by this subpart.

(ii) The owner or operator has been diligent in

obtaining the information.

(iii) The owner or operator submits a report according

to the provisions of paragraphs (e)(1)(iii)(A) through (C)

of this section.

(A) If this subpart expressly provides for supplements

to the report in which the information is required, the

owner or operator shall submit the information as a

supplement to that report. The information shall be
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submitted no later than 60 days after it is obtained, unless

otherwise specified in this subpart.

(B) If this subpart does not expressly provide for

supplements, but the owner or operator must submit a request

for revision of an operating permit pursuant to the State

operating permit programs in part 70 or the Federal

operating permit programs in part 71, due to circumstances

to which the information pertains, the owner or operator

shall submit the information with the request for revision

to the operating permit.

(C) In any case not addressed by paragraph

(e)(1)(iii)(A) or (B) of this section, the owner or operator

shall submit the information with the first Periodic Report,

as required by this subpart, which has a submission deadline

at least 60 days after the information is obtained.

In §63.1439(e)(4), paragraph (e)(4)(i) has been amended and

a new paragraph ((e)(4)(vii)) has been added in response to

comments, as follows:

"(i) Submittal dates. The Precompliance Report shall

be submitted to the Administrator no later than 12 months

prior to the compliance date. Unless the Administrator

objects to a request submitted in the Precompliance Report

within 45 days after its receipt, the request shall be

deemed approved. For new affected sources, the

Precompliance Report shall be submitted to the Administrator

with the application for approval of construction or

reconstruction required in paragraph (b)(2) of this section. 

Supplements to the Precompliance Report may be submitted as

specified in paragraph (e)(4)(vii) of this section.”

“(vii) Supplements to the Precompliance Report may be

submitted as specified in paragraph (e)(4)(vii)(A) or

(e)(4)(vii)(B) of this section. Unless the Administrator

objects to a request submitted in a supplement to the

Precompliance Report within 45 days after its receipt, the

request shall be deemed approved. 

(A) Supplements to the Precompliance Report may be

submitted to clarify or modify information previously

submitted.

(B) Supplements to the Precompliance Report may be

submitted to request approval to use alternative monitoring

parameters as specified in paragraph (e)(4)(iii) of this

section; to use alternative continuous monitoring and

recordkeeping, as specified in paragraph (e)(4)(iv) of this

section; to use alternative controls, as specified in

paragraph (e)(4)(v) of this section; or to include a

provision for ceasing to collect monitoring data during a

start-up, shutdown, or malfunction, in the start-up,
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shutdown, and malfunction plan, when that monitoring

equipment would be damaged if it did not cease to collect

monitoring data, as specified in paragraph (e)(3)(vi) of

this section.” 

2.15.14 Revise Exemptions from Recordkeeping

Comment: One commenter (IV-D-04) requested that EPA revise

§§63.1430(e)(1)(vi) and (e)(2) to avoid unfair double penalties

and retroactive violations. Section 63.1430(e)(1)(vi) provides

an exemption from certain recordkeeping requirements if batch

vents meet two requirements: (1) the batch vents are in

compliance with the aggregate 90 percent HAP reduction

requirement of §63.1425(c)(1); and (2) the control device is

operating at all times. Similarly, §63.1430(e)(2) provides an

exemption from recordkeeping if certain continuous process vents

are "in compliance with" the Group 1 requirements of

§63.1425(c)(3). The commenter cited the example of a facility

that was relying on this exemption from recordkeeping, and then

(perhaps 10 years later) the control device went "down" or there

was an instance of noncompliance with the emission control

requirements. This could result in a penalty for failure to meet

the required level of control. Also, it appears that the owner

or operator would immediately lose the exemption from

recordkeeping. For these reasons, the commenter requested that

EPA revise these two paragraphs in §63.1430(e) as follows:

"(1)* * *

(vi) If the combination of all process vents from batch

unit operations associated with the use of an organic HAP to

make or modify a polyether polyol product process vent is in

compliance with is subject to §63.1425(c)(1), and the

combustion, recovery, or recapture device is operating

intended to operate at all times, none of the records in

paragraphs (b)(1)(i) through (b)(1)(v) of this section are

required.

(2) Process Vents from Continuous Unit Operations.

...Owners or operators of combined streams that are in

compliance with subject to the Group 1 requirements of

§63.1425(c)(3) are not required to keep these records."
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Response: The Agency has reviewed the provisions in 

§§63.1430(e)(1)(vi) and (e)(2) and agrees with the commenter that

some clarification is needed to avoid the possibility of double

penalties and retroactive violations. The appropriate

clarifications have been incorporated into the final rule.

2.15.15 Recordkeeping Retention Revision

Comment: Two commenters (IV-D-04, IV-D-05) expressed

concern over the wording in §63.1439(h)(1)(vi)(D) which requires

industry to keep certain records for a specified period beginning

when the records are "last employed." The commenters requested

that this section be revised to base all mandatory retention

periods for records on the date when the record was "created,"

not on the date when the record as last employed. This revision

would be consistent with the HON litigation settlement

amendments. As an alternative, these provisions could allow

owners or operators to send the superseded documents to EPA

instead of requiring industry to keep them. Commenter IV-D-05

provided the following wording for §63.1439(h)(1)(vi)(D), which

is consistent with the HON litigation amendments.

"Owners and operators subject to paragraph

(h)(1)(vi)(B) of this section shall retain the current

description of the monitoring system as long as the

description is current, but not less than 5 years from the

date it was created last employed...."

Response: For purposes of consistency with other rules, the

Agency has amended §63.1439(h)(1)(vi)(D) to base retention

periods for records on the date when the record was created. 

Therefore, paragraph (D) has been amended as follows:

(D) Owners and operators The owner or operator subject

to paragraph (h)(1)(vi)(B) of this section shall retain the

current description of the monitoring system as long as the

description is current, but not less than 5 years from the

date it was last employed. The current description shall,

at all times, be retained on-site or be accessible from a

central location by computer or other means that provides

access within 2 hours after a request. The owner or
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operator shall retain the most recent all superseded

descriptions for at least until 5 years from after the date

it was last employed of their creation. Superseded

descriptions shall be retained on-site (or accessible from a

central location by computer or other means that provides

access within 2 hours after a request) for at least 6 months

after their creation. Thereafter, superseded descriptions

may be stored off-site." 

The vague time frame indicated by the use of the term “last

employed” has been replaced with the more concrete date (the date

of the document’s creation) as requested by the commenter, but

the new language is more specific than the HON, in that it

requires that all descriptions less than 5 years old be

maintained. This ensures that there will always be a record of

the past five years, no matter how often the descriptions are

replaced. 

2.15.16 Exclusion of Equipment Leaks to the Periodic Reporting

Requirements

Comment: One commenter (IV-D-04) stated that

§63.1439(e)(6)(iii)(D)(2) should not require a report every time

a valve or connector is installed and requested that EPA

expressly exclude equipment leaks, because it is routine to add

new equipment leak points. Therefore, the commenter requested

that §63.1439(e)(6)(iii)(D)(2) be revised as follows:

"Notification if one or more emission points (other than

equipment leaks), or one or more PMPU is added to an

affected source."

Response: The Agency agrees that a report should not be

required every time a routine valve or connector is installed. 

Therefore, the Agency has amended §63.1439(e)(6)(iii)(D)(2) in

the final rule, but changed the wording to be consistent with the

rest of the rule. Section 63.1439(e)(6)(iii)(D)(2) in the final

rule reads: 

"Notification if one or more emission points (other than

equipment leak components subject to §63.1434), or one or
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more PMPU is added to an affected source. The owner or

operator shall submit the information contained in

paragraphs (e)(6)(iii)(D)(2)(ii) (e)(6)(iii)(D)(2)(i) and

(ii) through (e)(6)(iii)(D)(3)(iii) of this section."

2.15.17 Record of Preparation of Standards

Comment: One commenter (IV-D-05) maintained that the

"record of preparation of standards," cited in

§63.1439(e)(5)(i)(B), should not be required for standards not

prepared by the source, such as standards that are obtained from

EPA or that are obtained as certified standards.

Response: The Agency agrees that the "record of preparation

of standards" should not be required for standards not prepared

by the owner or operator of the source. Therefore,

§63.1439(e)(5)(i)(B) has been amended to incorporate this change.

2.15.18 Periodic Reports

Comment: One commenter (IV-D-04) stated that

§63.1439(e)(6)(ii) requires a certification that the affected

source was "in compliance" for the previous 6-month period. The

commenter believed that this section requires a certification

even if there were compliance exceptions. If so, then the

commenter requested that the paragraph be revised to say that. 

Commenter IV-D-04 further claimed that §63.1439(e)(6)(i)

appears to have the timing backward. Paragraph 63.1439(e)(6)(i)

states that, after the first Periodic Report, subsequent reports

must cover each "preceding" 6-month period. This seems to be

backward. To the commenter, "preceding" means "earlier." So,

taken literally, this means the second Periodic Report must cover

the 6-month period before the period that was covered in the

first Periodic Report and so on. The commenter recommended that,

instead of "preceding," the paragraph should use the word

"subsequent." Another commenter (IV-D-05) provided the following

revision of paragraph §63.1439(e)(6)(ii) for clarity:
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"If none of the compliance exceptions in paragraphs

(e)(6)(iii) through (e)(6)(vii) of this section

occurred during the 6-month period, the Periodic Report

required by paragraph (e)(6)(i) of this section shall

be a statement that the affected source was in

compliance there were no compliance exceptions as

described in this paragraph, for the preceding 6-month

period and that none of the activities specified in

paragraphs (e)(6)(iii) through (e)(6)(vii) of this

section occurred."

Commenter IV-D-04 supported edits to this section that were

suggested by commenter IV-D-05.

Response: Because §63.1439(e)(6)(viii)(A) discussed

reporting requirements for time periods including compliance

exceptions, Commenter IV-D-04 is mistaken in thinking that

§63.1439(e)(6)(ii) needed to be edited to included periods with

compliance exceptions. The purpose of §63.1439(e)(6)(ii) is to

minimize the periodic reporting burden on owners or operations

with no compliance exceptions. However, the EPA agrees with the

commenters that the proposed language in §63.1439(e)(6)(ii) was

unclear, both regarding what must be reported, and what time

period the report is expected to cover. The EPA agrees that “the

affected source was in compliance” should be replaced with the

term “there were no compliance exceptions.” However, the EPA

does not agree that replacing the word “preceding” with the word

“subsequent" would correctly express the intent of the paragraph. 

Rather, the EPA has revised §63.1439(e)(6)(ii) to read as

follows:

"If none of the compliance exceptions in paragraphs

(e)(6)(iii) through (e)(6)(vii) of this section occurred

during the 6-month period, the Periodic Report required by

paragraph (e)(6)(i) of this section shall be a statement

that the affected source was in compliance there were no

compliance exceptions as described in this paragraph, for

the preceding 6-month period covered by that report and that

none of the activities specified in paragraphs (e)(6)(iii)

through (e)(6)(vii) of this section occurred during the

period covered by that report."
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The EPA feels that §63.1439(e)(6)(i) is clear about when Periodic

Reports are due, and what time period each covers, and has made

no changes to the proposed language for §63.1439(e)(6)(i).

2.15.19 Predominant Use Reporting

Comment: Two commenters (IV-D-04, IV-D-05) requested that

§63.1439(e)(6)(vi) be clarified. This section requires a report

for any change to the predominant use determination for a storage

vessel. The commenters believed that this meant a storage vessel

that belongs to the affected source after the change. The

commenters requested that the paragraph be revised to clarify the

intent, but each had different suggestions. Commenter IV-D-05

suggested the following language, noting that the reference

should be to paragraph (f)(8) and not (f)(6):

"The results for each change to a predominant use

determination for a storage vessel belonging to an affected

source subject to this subpart after the change that is made

under §63.1420(f)(8)."

Response: For the purposes of the Periodic Report

requirements [§63.1439(e)(6)(vi)], the EPA is interested in any

subsequent action that may change the predominant use of a

storage vessel. However, the EPA does believe it is appropriate

to specify the changes that must be reported. Therefore, the

final rule requires that the results for each reevaluation of

predominant use of a storage vessel be reported if the vessel

begins receiving material from (or sending material to) a process

unit that was not included in the initial determination, or if

the storage vessel ceases to receive material from (or send

material to) a process unit that was included in the initial

determination. Also, because the EPA is only interested in

changes in the predominant use of the storage vessel, only the

paragraphs in §63.1420(f) that apply to changes in predominant

use should be referred to in §63.1439(e)(6)(vi). For this

reason, the EPA agrees with commenter IV-D-05 about the cross-
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reference, and has changed the reference in §63.1439(e)(6)(vi) so

that it refers to §63.1420(f)(8).

Comment: Commenter IV-D-04 believed that the citations to

§63.1420(f)(6) in §§63.1439(e)(5)(v) and (e)(6)(vi) should

probably refer to §63.1420(f)(3) and not (f)(6), because

paragraph (f)(3) deals with assigning storage vessels to process

units on the basis of predominant use. 

Response: Section 63.1439(e)(5)(v) pertains to initial

predominant use determination, whereas §63.1439(e)(6)(vi)

pertains to a change in predominant use. For these reasons,

§63.1439(e)(5)(v) should cite §63.1420(f)(1) through (7), which

specify procedures to follow for initial predominant use

determination. Further, §63.1439(e)(6)(vi) should cite

§63.1420(f)(8), which addresses a change in the utilization of

the storage vessel.

2.15.20 Alternative Continuous Monitoring and Recordkeeping

Comment: One commenter (IV-D-04) agreed with

§63.1428(g)(3)(ii), which states that if process changes do not

result in a change in Group status at a Group 2 process vent from

a batch unit operation, no reporting is required. However, the

commenter requested that a similar paragraph be added specifying

that, if the group status of a Group 2 process vent from a

continuous unit operation is unchanged, no report would be

required.

Response: The Agency has added a new paragraph as

§63.1428(h)(2)(iii), clarifying that if, after the TRE index

value recalculation, it is determined that a Group 2 process vent

from a continuous unit operation has a TRE index value of 4.0 or

greater, no report is required for that Group 2 process vent. 

However, the EPA is still requiring a report to be submitted if
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the TRE index value changes from being above 4.0 to less than 4.0

but greater than 1.0, despite the fact that the process vent

remains Group 2. Therefore, the requirements in

§63.1428(h)(2)(ii) and §63.1430(j) have not been changed based on

this comment.

2.15.21 Consolidation of Periodic Reporting

Comment: Two commenters (IV-D-04, IV-D-05) requested that

§63.1439(e)(6) be clarified to allow a single Periodic Report

instead of three different Periodic Reports for existing and new

affected sources, one for the general requirements, one for

equipment leaks, and one for heat exchange systems. The

commenters suggested adding the following sentence to the end of 

§63.1439(e)(6) to accomplish this: "All of the information

required to be reported in this subsection may be submitted in

one report."

Response: The Agency agrees that the reports required under

§63.1439(e)(6) may be combined into one report. Therefore, the

EPA has added the phrase “as part of the Periodic Report required

by this paragraph (e)(6)” to the end of §63.1439(e)(6).

2.15.22 Group Status Change Reporting

Comment: One commenter (IV-D-04) expressed concern about the

requirement in §63.1439(e)(6)(iii)(D)(1) to report any process

change if "the group status of any emission point changes." This

would seem, literally, to require reporting even if the status

changed from Group 1 to Group 2. The commenter claimed that

reports should be required only if the status changes from Group

2 to Group 1. The commenter requested that this paragraph be

revised to say "the group status of any emission point changes

from Group 2 to Group 1."
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Response: The intent of §63.1439(e)(6)(iii)(D)(1) in the

proposed rule was to require reporting only if the status changes

from Group 2 to Group 1. However, the EPA would like to remind

owners and operators that, until notification is made that a

Group 1 emission point has become a Group 2 emission point, the

owner or operator will be required to comply with the Group 1

requirements for that emission point. Therefore, to clarify this

intent, the Agency has amended the first sentence of paragraph

§63.1439(e)(6)(iii)(D)(1) as follows: 

“Notification if a process change is made such that the

group status of any emission point changes from Group 2 to

Group 1. The owner or operator is not required to submit a

notification of a process change if that process change

caused the group status of an emission point to change from

Group 1 to Group 2. However, until the owner or operator

notifies the Administrator that the group status of an

emission point has changed from Group 1 to Group 2, the

owner or operator is required to continue to comply with the

Group 1 requirements for that emission point. This

notification may be submitted at any time. The information

submitted shall include a compliance schedule, as specified

in paragraphs (e)(6)(iii)(D)(2)(i) and

(e)(6)(iii)(D)(2)(ii)of this section, for emission points

that change from Group 2 to Group 1 as specified

§63.1420(g)(); or for process vents under the conditions

listed in §63.1429(g)(3)(i). This information may be

submitted in a separate report, as specified in §63.1430(i).

(i) The owner or operator shall submit to the

Administrator for approval a compliance schedule and a

justification for the schedule.

(ii) The Administrator shall approve the compliance

schedule or request changes within 120 days of receipt of

the compliance schedule and justification.

2.15.23 Excursions

Comment: One commenter (IV-D-04) noted that neither emission

points nor process sections have excursions. The commenter

stated that only control devices or recovery devices have

excursions. Therefore, it was requested that

§63.1439(e)(6)(viii) be revised to specify "control devices" or

"recovery devices" instead of "emission point" or "process
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sections." Another commenter (IV-D-05) expressed the same

concern and suggested that "control device" be used in lieu of

"process section" in §63.1439(e)(6)(viii).

Response: The Agency agrees that neither emission points

nor process sections have excursions. Paragraph

§63.1439(e)(6)(viii) of the final rule refers to “A control or

recovery device for a particular emission point or process

section” that has more excursions, as defined in §63.1438(f),

than the number of excused excursions allowed under §63.1438(g).

In the final rule, §63.1439(e)(6)(viii) also provides more

specific guidelines for when the quarterly reports are due, and

what they must contain.

2.15.24 Alternative Continuous Monitoring for Storage Vessels

Comment: One commenter (IV-D-04) requested that §63.1439(f)

be clarified to exclude storage vessel monitoring plans. This

section establishes a detailed procedure for situations where an

owner or operator has been directed to set unique monitoring

parameters. According to the commenter, this detailed procedure

(apparently borrowed from the HON) was not intended to apply, and

is not appropriate, in situations where the rule directs an owner

or operator to establish a monitoring plan for storage vessels. 

The corresponding paragraph of the HON was amended to make that

clear, by saying paragraph (f) applies only when specifically

referenced. The commenter requested that EPA do likewise in this

rule. Another commenter, IV-D-05, recommended revising the

provisions to avoid the misimpression that alternative monitoring

parameters must be requested for every storage vessel monitoring

plan and provided the following revision of paragraph (f):

"The owner or operator who has been directed by any section

of this subpart that specifically references this paragraph or

any section of another subpart referenced by this subpart that
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specifically references this paragraph to set unique monitoring

parameters...."

Commenter IV-D-04 supported this recommended language

change.

Response: The Agency agrees that this detailed procedure

was not intended to apply in situations where the rule directs

the establishment of a monitoring plan for storage vessels. 

Therefore, in order to clarify that these provisions apply only

when specifically referenced, §63.1439(f) has been amended as

follows:

"(f) Alternative monitoring parameters. The owner or

operator of an affected source who has been directed by any

section of this subpart, or any section of another subpart

referenced by this subpart, that specifically references

this paragraph to set unique monitoring parameters, or who

requests approval to monitor a different parameter than

those listed in §63.1432 for storage vessels, §63.14267 for

ECO, §63.1429 for process vents, or §63.143 of subpart G for

process wastewater shall submit the information...." 

2.15.25 Cross-referencing in Reduced Recordkeeping

Comment: One commenter (IV-D-04) requested that EPA either

add more cross-references, or delete the current crossreferences, from §63.1439(h). This section provides that a

"reduced recordkeeping" program may be implemented as an

alternative to the continuous operating parameter monitoring and

recordkeeping requirements in the following three locations:

§63.1432 for storage vessels; §63.1429 for process vents; and

§63.1433 for wastewater. According to the commenter, the HON (in

which the reduced recordkeeping program originated) has a total

of ten cross-references to locations where the "normal" operating

parameter monitoring and recordkeeping requirements are located. 

Since the proposed rule is as complex as the HON, the commenter

questioned whether the proposed rule omits any necessary crossreferences from this paragraph. The commenter suggested that the
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easiest way to resolve this concern is to revise the first

sentence of §63.1439(h) as follows:

"For any parameter with respect to any item of

equipment, the owner or operator may implement the

recordkeeping requirements in paragraph (h)(1) or (h)(2) of

this section as alternatives to the continuous operating

parameter monitoring and recordkeeping provisions listed in

§63.1432 for storage vessels, §63.1429 for process vents,

and §63.1433 for wastewater that would otherwise apply under

this subpart...."

Response: The Agency agrees that the proposed language may

lack clarity. Therefore, the Agency has revised the first

sentence of §63.1439(h) as suggested by the commenter. 

2.15.26 Operating Permit Application

Comment: Two commenters (IV-D-04, IV-D-05) stated that

§63.1439(e)(8) is unclear. Commenter IV-D-05 claimed that there

are many other things in addition to the information listed in

paragraph (e)(4) that must be submitted in an operating permit

application and strongly recommended that EPA provide a

comprehensive list of the monitoring, recordkeeping, reporting,

and operating permit requirements applicable to this rule. 

Therefore, at a minimum, for clarity, both commenters suggested

the following revision:

"(8) Operating permit application. An owner or operator

who submits an operating permit application instead of a

Precompliance Report shall submit the information specified in

paragraph (e)(4) of this section, Precompliance Report, as

applicable, with the operating permit application."

Response: The Agency recognizes that the information

required in an operating permit application goes beyond that 

specified in §63.1439(e)(4). Therefore, the EPA has revised

§63.1439(e)(8) as suggested by the commenters.

2.15.27 Manual Reading
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Comment: One commenter (IV-D-05) stated that

§63.1439(g)(2)(i) refers to "manual" reading and recording of

parameter values, but instead should say "visual" or "sensory."

Response: For clarity, the Agency has substituted the word

"visual" for "manual" in §63.1439(g)(2)(i) in the final rule.

2.15.28 "Any Other Information" in Sections 63.1439(e)(5)(i)(B)

and 63.1439(e)(6)(iv)(B)

Comment: Two commenters (IV-D-04, IV-D-05) expressed concern

over the use of the words "any other information" in

§§63.1439(e)(5)(i)(B) and 63.1439(e)(6)(iv)(B), as well as the

words "any information" or "any information required" that appear

elsewhere in the proposed rule. The commenter stated that

compliance with such vaguely worded provisions is impossible and

requested that EPA avoid using these words or carefully describe

where industry must look for the referenced requirement. 

Commenter IV-D-05 recommended amending these paragraphs to read: 

"... any other information required by the test method to be in

the test report." 

These two commenters also questioned the need for the words

"and any other required information" in the last sentence of

§63.1439(e)(5)(i)(A) which reads, "For additional tests performed

for the same kind of emission point using the same method, the

results and any other required information shall be submitted,

but a complete test report is not required." The commenter

believed that these words were confusing because they have no

idea what "any other required information" means. They requested

that EPA delete these words from this paragraph. They maintained

that if there is some specific information that EPA wants

submitted, this paragraph should either name it, or give the

specific citation where it is identified.
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Response: The commenter's request that the EPA change "any

other information" or "any information" to "any other information

required by the test method to be in the test report" clarifies

the EPA's intent. This revision was incorporated throughout the

final rule, whenever those phrases referring to test methods were

used. 

2.15.29 §63.1439(g)(3)

Comment: One commenter (IV-D-05) claimed that

§63.1439(g)(3), allowing the recording of hourly averages instead

of 15-minute data points, is no longer necessary as the regular

provisions of the rule allow the same averaging. The commenter

therefore recommended deleting subsection (g)(3) and renumbering

subsection (g)(4) accordingly.

Response: The EPA agrees with the commenter that it is not

necessary to state that hourly averages are allowed in

§63.1439(g)(3); however, the EPA chooses to retain this language

in the final rule as a clarification. The EPA feels that this

clarity is warranted, since many other rules require 15-minute

data points in their definition of a continuous recorder. 

2.16 EDITORIAL 

2.16.1 "The Owner or Operator" Versus "Each Owner or Operator"

Comment: One commenter (IV-D-05) maintained that usually the

text requires "the owner or operator" or "an owner or operator"

to comply. If "each" owner or operator or "all" owners and

operators were required to comply, in cases where there are two

or more companies involved (e.g., a joint venture), then the

burdens of the rule would be duplicated for no reason. The

commenter did not believe that is EPA’s intent. The commenter

requested EPA to change "each owner or operator" to "the owner or

operator" and change "owners and operators" to "the owner or

operator" (and change the following verb agreement as
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appropriate) in the following sections: 63.1420(b);

63.1420(e)(5)(i); 63.1420(e)(5)(ii); 63.1429(a); 63.1430(b);

63.1430(d); 63.1430(e)(1); 63.1430(e)(2); 63.1430(f)(2);

63.1430(f)(3); 63.1430(f)(4); 63.1430(f)(5); 63.1420(g)(1);

63.1439(a); 63.1439(b)(2); 63.1439(e)(3); 63.1439(e)(5);

63.1439(e)(6).

Response: The EPA appreciates the comment, and agrees with

the commenter that the EPA did not intend to duplicate the

responsibilities of the rule to joint venture partners. 

Therefore, the EPA has revised the final rule as requested. 

2.16.2 Section 63.1420(e)(3)

Comment: One commenter (IV-D-05) recommended deleting the

word "considered" from the first sentence in §63.1420(e)(3).

According to the commenter, the process either is a PMPU, or is

not a PMPU. The commenter also suggested moving the phrase "if

the plant site is a major source" from the end of the second

sentence to the beginning of that sentence to clarify that the

whole sentence applies only to major sources. For grammatical

reasons, it was also suggested that the word "is" in the second

sentence be deleted.

Response: The EPA appreciates the comments and has made

these revisions in the final rule at §63.1420(e)(1)(iv), which

was §63.1420(e)(3) at proposal.

2.16.3 Section 63.1420(e)(5)(i)

Comment: One commenter (IV-D-05), for clarity, recommended

changing the first sentence in §63.1420(e)(5)(i) to read:

"... shall determine the applicability of the

provisions (e.g., the Group status) for each emission point

that is part of that flexible operation unit ...." 
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The commenter, for clarity, also recommended changing the

last sentence in paragraph (i) to read:

"... Based on this finding, the owner or operator shall

comply with the applicable standards of this subpart for each

emission point, as appropriate, at all times, regardless of what

as though the primary product is being produced."

Response: The EPA has rewritten §63.1420(e), and has

eliminated §63.1420(e)(5)(i) and the phrases "regardless of what"

and "shall determine the applicability of the provisions" from

this section of the final rule.

2.16.4 Section 63.1420(e)(5)(iii)

Comment: One commenter (IV-D-05) stated that paragraph

63.1420(e)(5)(iii) states that the owner or operator shall comply

"only with either" (b)(1) or (b)(2). That could be interpreted

as forbidding compliance with both. The commenter recommended

changing the text to delete "only":

"The owner or operator shall comply with either paragraph

(b)(1) or (b)(2)...."

Response: The EPA did not intend for §63.1420(e)(5)(iii)

to be interpreted as forbidding compliance with both (b)(1) and

(b)(2). Therefore, in the final rule [as §63.1420(e)(5)(i)],

this language has been clarified to avoid any possible

misinterpretation.

2.16.5 Sections 63.1427(h)(1) and (h)(2)

Comment: One commenter(IV-D-05) stated that §63.1427(h)(1)

and (h)(2) allow the owner or operator to monitor or establish,

respectively, "one" of the parameters in paragraphs (i) through

(iii). However, at the end of §63.1427(h)(1)(ii) and (h)(2)(ii)

the proposed rule said "and" instead of "or." Therefore, the

commenter recommended revising the text in §63.1427(h)(1)(ii) and

(2)(ii) to say "or."
2-194

Response: The Agency agrees with this comment. However,

since there is an "or" at the end of both §63.1427(i)(1)(iii) and

(i)(2)(iii) (which were §63.1427(h)(1)(iii) and (h)(2)(iii) at

proposal), the word "and" was simply removed at the end of

§63.1427(i)(1)(ii) and (i)(2)(ii), in the final rule.

2.16.6 Section 63.1427(1)(iv)

Comment: One commenter (IV-D-05) understood that the

concentration in §63.1427(i)(1)(iv) is to be determined at the

"onset of the ECO" rather than at the "end of the onset of ECO." 

Therefore, the commenter recommended revising the text

accordingly.

Response: The phrase "end of the onset of ECO" has been

corrected in the final rule to use the correct phrase, "onset of

ECO".

2.16.7 Section 63.1433(a)(9)

Comment: One commenter (IV-D-05) requested that

§63.1433(a)(9) be revised to add "applicable" to read "the

applicable compliance dates specified in §63.1422 shall

apply...."

Response: The Agency agrees with the commenter's suggestion

and has revised the final rule accordingly.

2.16.8 Section 63.1433(b)

Comment: One commenter (IV-D-04) requested that EPA give

§63.1433(b) a heading, i.e., "Maintenance wastewater" to call

attention to it, because it is brief and could be considered part

of the preceding text for process wastewater.

Response: The EPA appreciates the suggestion to provide a

title for §63.1433(b) such as "Maintenance wastewater." 
2-195

Therefore, the EPA titled that section as requested and, for

consistency, titled §63.1433(a) "Process wastewater."

2.16.9 Section 63.1431(f)(1)

Comment: One commenter (IV-D-05) recommended, for clarity,

that the text in §63.1431(f)(1) be revised to delete the word

"control" at the end of the second sentence as follows:

"The owner or operator shall notify the Agency of the

intent to comply with the epoxide emission factor limitation

in §63.1425(b)(1)(iii) or (b)(2)(iii) without the use of

extended cookout or a combustion, recovery, or recapture

device. The owner or operator shall prepare an estimate of

the annual epoxide emissions control."

Response: The Agency agrees with the commenter that the

word "control" is inappropriate at the end of this sentence. The

Agency has revised the final rule to delete this word.

2.16.10 62 FR 46812, col. 3

Comment: One commenter (IV-D-04) requested that the EPA

correct the statement in the proposal preamble (62 FR 46812, col.

3) that referred to the Start-up, Shutdown and Malfunction Plan

as a "report" that must be submitted to the Administrator. The

commenter noted that the proposed rule, §63.1439(b)(1),

accurately considers the start-up, shutdown, and malfunction plan

to be a record that must be retained on-site. 

Response: The Agency realizes that the reference to the

Start-up, Shutdown and Malfunction Plan as a report was incorrect

in the preamble. The preamble for the final rule does not

include this erroneous information. 
2-196

2.16.11 Section 63.1438(b)(3)

Comment: One commenter (IV-D-05), recommended revising

§63.1438(b)(3) to be consistent with other parts of the rule

where "are" is replaced with "shall be," as follows:

"Process vents from batch unit operations. For process

vents from batch unit operations, during initial compliance

testing, the appropriate parameter shall be monitored

continuously during the entire test period. The monitoring

level(s) are shall be those established during the

compliance test demonstration."

Response: The EPA intended to have consistent language

throughout the rule. Therefore, §63.1438(b)(2) of the final rule

(which was §63.1438(b)(3) at proposal) was revised as suggested

by the commenter.

2.16.12 Heading in §63.1420(c)

Comment: One commenter (IV-D-05) requested that, for

purposes of clarity, the EPA change the heading in §63.1420(c) as

follows:

"Emission points included in the affected source but

not subject to the provisions of this subpart."

Response: The EPA appreciates the comment, and revised the

final rule to add this language to the title.

2.16.13 Section 63.1420(c)(2)

Comment: One commenter (IV-D-05) suggested, for clarity that

EPA revise §63.1420(c)(2) as follows:

"(2) Stormwater managed in from segregated sewers."

Response: The EPA agrees with this revision and has

incorporated it into the final rule.

2.16.14 Section 63.1420(d)
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Comment: For grammatical reasons, one commenter (IV-D-05)

requested that EPA revise §63.1420(d) as follows:

"...and are exempted from the requirements of both this

subpart and from the provisions of subpart A."

Response: The EPA agrees that the commenter's suggested

language is grammatically correct. Therefore, the EPA

incorporated the commenter's suggested language into the final

rule.

2.16.15 Section 63.1420(e)(1)

Comment: One commenter (IV-D-05) stated that the word "only"

needs to come after (not before) "manufactures" in

§63.1420(e)(1). In the current wording, it could be interpreted

to mean that a process unit "only manufactures" one product

(instead of manufacturing, processing, and shipping it). It

should read "manufactures only" one product. Therefore, for

clarity, the commenter recommended changing this sentence as

follows:

"If a process unit only manufactures only one product..."

Response: The EPA agrees that the phrase quoted may be

incorrectly interpreted. Therefore, the EPA has changed the

language in the final rule to the language suggested by the

commenter at §63.1420(e)(1)(i), which was §63.1420(e)(1) at

proposal.

2.16.16 Section 63.1422(d)(2)(iv) and (d)(5)

Comment: One commenter (IV-D-04) stated that in

§63.1422(d)(2)(iv) and (d)(5), there are bracketed comments

saying to insert a date that is a certain amount of time "from"

the date of publication of the final rule. The commenter

requested that these bracketed words say "after" the date of
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publication of the final rule, as the commenter believes EPA

intended.

Response: In the proposed rule, these bracketed statements

were included to show the time frame when compliance would be

required. The final rule contains actual dates, so the

commenter's concern no longer exists.

2.16.17 Section 63.1420(f)(7)(i)

Comment: One commenter (IV-D-04) requested that "raw

materials" in §63.1420(f)(7)(i) be revised to read "raw

material."

Response: The commenter's request pointed out the

possibility that someone reading the rule could interpret this

section to pertain only if the process had more than one raw

material. This was not the EPA's intent. Therefore, the EPA

revised the final rule as requested by the commenter.

2.16.18 Section 63.1424(a)

Comment: One commenter (IV-D-05) stated that §63.1424(a)

refers to paragraph (c) or (d), which do not exist. Therefore,

the commenter recommended changing the text as follows:

"(a) Except as provided in paragraphs (b) through (d)

of this section ....."

Response: The EPA appreciates the commenter bringing this

typographical error to the EPA's attention. Section 63.1424(a)

of the final rule was revised to only cite paragraph (b).

2.16.19 Section 63.1425(c)(4)(i)

Comment: One commenter (IV-D-05) maintained that

§63.1425(c)(4)(i) references the wrong subsection. The commenter
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recommended revising the text, to refer to §63.1428(h)(2) instead

of §63.1428(h)(4).

Response: The commenter correctly stated that

§63.1425(c)(4)(i) should reference §63.1428(h)(2) and not (h)(4). 

Therefore, the EPA revised the language in the final rule as

suggested. 

2.16.20 Section 63.1426(c)

Comment: One commenter (IV-D-05) noted that §63.1426(c) has

an "either" in the wrong place. Therefore, the commenter

recommended changing the text to read:

"...may be measured either as either total organic HAP

or as TOC minus methane and ethane...."

Response: The EPA agrees and has revised the final rule,

putting the word "either" in the position suggested by the

commenter.

2.16.21 Section 63.1426(c)(1)(i)(C)(ii), (c)(3)(ii), and (e)(1)

Comment: One commenter (IV-D-07) requested that the

following editorial corrections be made in the final rule:

First, §63.1426(c)(1)(ii) has two improper cites:(1) 

§63.1425(b)(1)(ii) is "reserved" and does not require any ppmv

limit; and (2) the reference to §63.1425(b)(2)(iii) should be to

§63.1425(b)(2)(ii), which is the correct reference to the ppmv

standard.

Second, in §63.1426(c)(3)(ii), "of the HAP of concern"

should be "or the HAP of concern".

Third, in §63.1426(e)(1), there is a typo just above

equation 6: the word "determination" should be "determined".

Response: The EPA intended to cite §63.1425(b)(1)(ii) as a

concentration cutoff limit for new sources. However, at the time
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of proposal, the EPA had not decided on a value for this

concentration limit, and instead simply “reserved” this

paragraph. Between proposal and promulgation, the EPA decided on

a 20 ppmv limit, which was inserted into §63.1425(b)(1)(ii) of

the final rule. Therefore, the EPA disagrees with the

commenter's interpretation of the first citation for a ppmv HAP

limit in §63.1426(c)(1)(ii). 

However, the commenter correctly stated that the second

citation in §63.1426(c)(1)(ii) should be to §63.1425(b)(2)(ii),

instead of to §63.1425(b)(2)(iii). Therefore, the EPA revised

§63.1426(c)(1)(ii) in the final rule accordingly. 

With regard to the commenter’s second comment, the EPA

disagrees: §63.1426(c)(3)(ii) was intended to say “of the HAP of

concern.” The phrase “of the HAP of concern” refers to the HAP

listed in Table 4 of subpart PPP, which limits the owner or

operator to having to take into consideration the concentrations

of the 6 HAP listed in that table, rather than having to consider

all 188 of the HAP currently listed under §112(b) of the Clean

Air Act. With regard to the commenter’s third comment, the EPA

agrees that the word “determination” in §63.1426(e)(1) should

have been “determined,” and has made the change suggested by the

commenter, in the final rule. 

2.16.22 Section 63.1426(e)(1)

Comment: One commenter (IV-D-05) cited §63.1426(e)(1) which

requires owners or operators to determine the emission reduction

for each group of process vents subject to "the same paragraph"

of §63.1425. According to the commenter, this may work for

paragraphs (b),(c) and (d), but it will not work for other

paragraphs of §63.1425. Therefore, the commenter recommended

that §63.1426(e)(1) be revised as follows:

"The owner or operator shall determine the organic HAP

emission reduction for process vents in a PMPU using
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Equation 6. The organic HAP emission reduction must be

determined for each group of process vents subject to the

same paragraph (i.e., paragraph (b), (c) or (d)) of §63.1425

of this subpart. For instance, process vents that emit

epoxides are subject to paragraph (b) of §63.1425. 

Therefore, the organic HAP (i.e., epoxide) emission

reduction must be determinationed for the group of vents in

a PMPU that are subject to this paragraph."

Response: The EPA agrees that some of the citations in the

proposed §63.1426(e)(1) were incorrect. Therefore, the revisions

suggested by the commenter were incorporated into the final rule. 

2.16.23 "Pressure Decline Curve" Versus "Pressure Decay Curve"

Comment: One commenter (IV-D-05) requested, for consistency, 

changing "pressure decline curve" in §63.1427(i)(1)(i)(A) and (C)

to "pressure decay curve," a term that is used elsewhere. The

commenter has provided a definition for "pressure decay curve" in

§63.1423(b).

Response: The EPA intended to consistently use the term

"pressure decay curve." Therefore, the EPA replaced the phrase

"pressure decline curve" in §63.1427(j)(1)(i)(A) and (C) (in the

final rule) with "pressure decay curve." As discussed in section

23.17 of this document, the same change was made in the

definition of "product class."

2.16.24 Section 63.1427(l)(3)(ii)

Comment: One commenter (IV-D-05) recommended, for clarity,

revising the text in §63.1427(l)(3)(ii) to read:

"If the new operating conditions of the polyether

polyol product do not conform with the operating

characteristics of an existing product class, the owner or

operator shall establish a new product class and shall

comply with provisions of (l)(3)(i)(A) through (C) of this

section."
2-202

Response: The EPA inadvertently omitted the word "polyol"

from the sentence quoted by the commenter. Therefore, the EPA

revised the text in §63.1427(l)(3)(ii) (§63.1427(m)(3)(ii) in the

final rule) to insert the word "polyol." 

2.16.25 Section 63.1428(c)

Comment: One commenter (IV-D-05) recommended adding the

phrase "as selected by the owner or operator" in the first

sentence of §63.1428(c) to avoid ambiguity and for accuracy as

follows: 

"If the annual emissions of TOC or nonepoxide organic

HAP, as selected by the owner or operator, from the

combination of process vents from batch unit operations

...." 

Also, the commenter recommended changing the reference in the

same sentence from §63.1425(c)(4) to (c)(2) for accuracy.

Response: The EPA agrees with the commenter's first point

that a clarifying phrase after the first phrase in §63.1428(c)

would avoid ambiguity. However, the EPA does not believe that 

the phrase "as selected by the owner or operator" is appropriate. 

Instead, the EPA clarified the first phrase in §63.1428(c) by

adding "as applicable." The commenter also recommended changing

the reference in the same sentence from §63.1425(c)(4) to (c)(2). 

The EPA agrees with this recommended change and has incorporated

it into the final rule.

2.16.26 Section 63.1435(d)

Comment: One commenter (IV-D-05) suggested that §63.1435(d)

be changed to use the word "may" instead of the word "should."

Response: The Agency agrees that "should" is inappropriate

but disagrees that "may" is the correct term to use in

§63.1435(d). In the final rule, "should" has been replaced with

"shall."
2-203

2.16.27 Section 63.1439(b)

Comment: One commenter (IV-D-04) requested that two minor

errors in §63.1439(b) be corrected:

1. this section requires industry to keep a start-up,

shutdown and monitoring plan "onsite," which should be corrected

to "on-site" or "on site."

2. this section also requires industry to keep the plan "on

record" after it is developed, for a specified amount of time. 

The commenter suggested deleting the words "on record" because

they add no meaning to the sentence and could be misunderstood. 

The industry typically keeps their plans on paper or on computer,

not "on record."

Response: The EPA agrees with the commenter on both points. 

The EPA revised "onsite" to "on site." However, the entire

sentence containing "on record" has been removed. Therefore, no

additional change is needed.

2.16.28 Section 63.1439(e)(6)(iii)(A)

Comment: One commenter (IV-D-05) referred to the provisions

of §63.1439(e)(6)(iii)(A), which apply to owners or operators

complying with §63.1432 (storage vessels) through §63.1433

(wastewater). The commenter recommended revising this paragraph

to delete the references to process vents and heat exchange

systems because they do not apply.

Response: The EPA agrees that paragraph

63.1439(e)(6)(iii)(A) does not need references for information

required for process vents or heat exchange systems since

paragraph 63.1439(e)(6)(iii) refers to periodic reports for

storage vessels and wastewater. Therefore, the EPA deleted the

references for process vents and heat exchanger systems.

2.16.29 Section 63.1439(e)(6)(iii)(D)(1) and (f)(3)
2-204

Comment: One commenter (IV-D-04) pointed out that

§63.1439(e)(6)(iii)(D)(1) refers to §63.1429(g)(3)(i), and there

is no such section. The last major division in §63.1429 is

"(d)."

Also, §63.1439(e)(6)(iii)(D) has a reference to

(e)(6)(iii)(D)(4), and there is no such paragraph. They noted

that the reference should probably be changed to

(e)(6)(iii)(D)(3)

In addition, the commenter noted that the word "recording"

on the first line of §63.1439(f)(3) should be "reporting."

Response: Regarding §63.1439(e)(6)(iii)(D)(1), the EPA

agrees with the commenter, and deleted the second part of the

sentence, which at proposal read "or for process vents under

conditions listed in §63.1429(g)(3)(i)." The EPA also agrees

with the second comment about the incorrect cross-reference. The

EPA changed the final rule to refer to paragraph

(e)(6)(iii)(D)(3). Further, the EPA agrees that "recording"

should be "reporting" on the first line of §63.1439(f)(3), and

the EPA revised the wording accordingly.

2.16.30 Section 63.1426(c)(4)(iv), (c), and (c)(1)(i)(A)

Comment: One commenter (IV-D-04) requested that the

following editorial changes be made:

§63.1426(c)(4)(iv): Move "respectively" and place after 

"total organic HAP."

§63.1426(c): Correct placement of commas as follows:

"...an owner or operator using a combustion, recovery,

or recapture device to comply with an organic HAP

percent reduction efficiency requirement in section

§63.1425, (b)(2)(i), (c)(1), (c)(3), or (d), an

organic..."

§63.1426(c)(1)(i)(A): The word "vent" should be "vents."
Rbatchcycle '

Ee, u& (Ee, E) (1&

Raddon, i

100

) % (Ee, o) (1 &

Raddon, j

100

)

Ee, u

( 100

2-205

Response: The EPA agrees with all of the commenter's

editorial changes, and incorporated them into the final rule.

2.16.31 Equation 9

Comment: Commenter IV-D-05 recommended that Equation 9 for

determining the percent epoxide emission reduction for the batch

cycle in §63.1427(e)(1) be corrected. The commenter recommended

that the EPA revise the numerator, and provided the revised

equation.

Response: The EPA agreed with the commenter that Equation 9

needed to be revised. In the final rule, the Equation 9 reads as

follows: 

2.16.32 Section 63.1425(e)(2)(i)

Comment: Commenter IV-D-05 pointed out that the regulatory

language in §63.1425(e)(2)(i) states that continuous processes

should be controlled according to §63.1428(b). Paragraph

63.1428(b), however, deals with emissions from batch processes. 

The only provision in that section for continuous processes is

§63.1428(h). The commenter believed that the regulatory citation

should be changed to §63.1428(h).

Response: The commenter is correct. However, §63.1425(e)

has been reserved in the final rule, and §63.1428(h) is cited at

other places in the rule (e.g., the definition of Group 1

continuous process vent and §63.1425(c)), correctly.
2-206

2.16.33 Section 63.1425(f)

Comment: For clarity, one commenter (IV-D-05) recommended

changing the text in §63.1425(f) as follows:

"For each process vent in a PMPU that is, or is part

of, an affected source and that uses tetrahydrofuran (THF)

to produce one or more polyether polyol products...."

Response: The introduction paragraph to the process vent

control requirements section, §63.1425(a), states in the last

sentence: "The owners or operator of an affected source where

polyether polyol products are produced using tetrahydrofuran

shall comply with paragraph (f) of this section." Therefore, the

EPA believes that the language requested by the commenter is

redundant and was not incorporated into the final rule.

2.16.34 Section 63.1429(d)(3)

Comment: One commenter (IV-D-04) requested that

§63.1429(d)(3) be clarified. It requires the industry to specify

the "times" when an operating day begins and ends. Actually,

there are no "times;" there is only a "time." For example, if

the operating day runs from midnight to midnight, then "midnight"

is the time when one operating day begins and the previous

operating day ends. Under the proposed wording of this section,

the commenter believed that they would be subject to an

enforcement action, with penalties of up to $27,500, if they

specify only one time instead of two or more. The commenter

recommended that the word "times" be revised either to "time" or

to "time(s)."

Response: The EPA agrees with the commenter's request and

changed "times" to "time(s)" in the final rule.

2.16.35 Section 63.1439(e)(6)(v)
2-207

Comment: One commenter (IV-D-05), for clarity, suggested

that §63.1439(e)(6)(v) be changed to substitute "PMPU" for

"polyether polyol product" as follows: "...the results for each

change made to a primary product determination for a PMPU...."

Response: The EPA agrees that the primary product

determination is made on a PMPU basis. Therefore,

§63.1439(e)(6)(v) in the final rule was revised accordingly.

2.16.36 Section 63.1439(h)(1)

Comment: One commenter (IV-D-04) stated that unlike other

paragraphs of §63.1439(h)(1), which specify that certain

monitoring systems must alert the owner or operator "by alarm or

other means," paragraph (h)(1)(iv) says to alert the owner or

operator "by an alarm." The commenter sees no apparent reason

for this inconsistency and suggested that §63.1439(h)(1)(iv) be

revised as follows:

"(iv) The monitoring system will alert the owner or

operator by an alarm or other means, if the running average

parameter value ...."

Response: The EPA agrees with the commenter, and has

revised §63.1439(h)(1)(iv) accordingly.

2.16.37 Section 63.1427

Comment: One commenter (IV-D-04) requested that the EPA

correct the following minor typographical errors in §63.1427 to

avoid confusion. The comments are numbered, as follows:

(1) (c): "... by calculating the epoxide emissions, if any,

prior to the onset of the ECO, if any, plus the epoxide emissions

at the onset of the ECO...."

(2) (h)(1)(ii): The epoxide partial pressure in the

reactor; and or ....

(3) (h)(2)(ii): The reactor epoxide partial pressure at the

end of the ECO; and or ....

(4) (i)(2): Continuous Ongoing records....
2-208

(5) (k)(1)(ii): Within 180 days of after the production

of the new polyether polyol product, the owner or operator shall

submit a report updating the product list originally previously

submitted for the product class ....

(6) (l)(2): The owner or operator shall only update the

records specified in paragraphs (i)(1)(i)(A) through (G) of this

section for the product.

(7) (l)(3)(i)(A): The owner or operator shall update the

list of products for the product class required by paragraph

(i)(1)(ii) of this section that the product is leaving, and for

the product class that the product is entering, and shall record

....

(8) (l)(3)(i)(B): Within 180 days of after the change in

operating conditions for the polyether polyol product, the owner

or operator shall submit a report updating the product list

originally previously submitted for the product class ....

Another commenter (IV-G-02) supported the changes suggested

by Commenter IV-D-04, in particular the suggested changes to

§§63.1427(h)(1)(ii) and (h)(2)(ii).

Response: The EPA agrees with all eight of the commenter's

suggested corrections; and they were incorporated into the final

rule.

2.16.38 Section 63.1439(e)(5)(ii)(D)

Comment: Two commenters (IV-D-04, IV-D-05) provided

comments on §63.1439(e)(5)(ii)(D). One commenter (IV-D-04)

stated that paragraph (D) appears to have been borrowed by

mistake from another rule, perhaps the Group I Polymers and

Resins standard. It refers to monthly measurements of residual

organic HAP, a topic not germane to this rule, and it is ignored

in cross-references, so there is no way to reach it. The

commenter recommended that the paragraph be deleted from this

rule.

On the other hand, another commenter (IV-D-05) requested

that paragraph (D) be revised, for purposes of clarity, by adding

the words "where applicable" at the end of the provisions to read

as follows:
2-209

"The required information shall include a definition of the

affected source’s operating month for the purposes of determining

monthly average values of residual organic HAP, where

applicable."

Response: Section 63.1439(e)(5)(ii)(D) was inadvertently

included in this rule. The EPA deleted §63.1439(e)(5)(ii)(D)

from the final rule.

2.16.39 Section 63.1439(b)

Comment: One commenter (IV-D-04) maintained that in

§63.1439(b), one paragraph should be moved and two crossreferences should be corrected as follows:

1. Paragraph 63.1439(b)(1)(i)(C) should be moved because it

has nothing to do with records of start-up, shutdown and

malfunction.

2. Section 63.1439(b)(1)(i) mentions a paragraph

(b)(1)(i)(D); there is no such paragraph. Nor should there be a

paragraph (b)(1)(i)(C) as noted above. Therefore, the reference

to (b)(1)(i)(D) should be changed to (b)(1)(i)(B).

3. Section 63.1439(b)(1)(ii) also refers to paragraph

(b)(1)(i)(C) and, as noted above, does not belong here. 

Therefore, once it is moved, the reference to (b)(1)(i)(C) should

be changed to (b)(1)(i)(B).

Response: The EPA appreciates the comments regarding the

cross-referencing errors. Paragraph 63.1439(b)(1)(i)(C) was

moved to §63.1439(d)(8), and the other cross-references were

corrected, as recommended. 

2.16.40 Actual Date Versus "Date of Promulgation"

Comment: One commenter (IV-D-04) asserted that the EPA

should request the Office of the Federal Register to insert the

actual date or deadline in §63.1439(e)(3)(ii)(A) through (C)

instead of referring to the date of promulgation or the date of
2-210

publication. The commenter believed that this would avoid

confusion and could reduce the workload on owners or operators. 

The commenter stated that some people might not know what

"promulgation" means. The commenter added that even for owners

and operators that do know what “promulgation” means, the

language in proposed §63.1439(e)(3)(ii)(A) through (C) creates

extra work and increases the chance for mistakes or

misinterpretations. The commenter provided revisions to

paragraphs §63.1439(e)(3)(ii)(A) through (C) which provide for

the insertion of the actual date, and the commenter requested

that EPA revise those paragraphs accordingly in the final rule.

Response: The EPA appreciates the comment, and the final

rule includes specific dates in those paragraphs.

2.16.41 Changes to Several Equations

Comment: One commenter (IV-D-04) requested that EPA make

minor changes to several equations in the proposed rule:

1. Throughout the rule’s equations, wherever the term

"weight percent" is used, the weight fraction (or weight percent

expressed in decimal notation) should be used.

2. In Equation 9, there should be another "(" after the

minus sign and a ")" right after the second term in the

numerator.

3. Equation 13 should be: AEcontrol=(AEuncontrolled)[(100-

R)].

Response: Regarding the commenter's first suggestion,

Equation 11 is the only equation where a weight percent is used. 

The EPA agrees that a weight fraction can be used, but does not

find it necessary to change weight percent to weight fraction.

The EPA disagrees with the second comment, which requests

that a set of parenthesis be added to Equation 9 to subdivide the

second term, since an extra set of parenthesis around the second
2-211

term is not needed. The EPA’s reasoning is that, according to

algebraic rules, multiplication is conducted before addition or

subtraction, and addition or subtraction can be conducted in any

order. 

Finally, the EPA agrees with the commenter regarding

Equation 13. Equation 13 has been revised as suggested by the

commenter in the final rule.

2.16.42 Section 63.1420(h)(3)

Comment: One commenter (IV-D-05) stated that the first

sentence in §63.1420(h)(3) refers to the wrong subparagraph. For

clarity, the commenter recommended revising it as follows:

"During start-ups, shutdowns, and malfunctions when the

requirements of this subpart do not apply pursuant to paragraphs

(h)(1) through (h)(3)(2) of this section, the owner or operator 

shall implement, to the extent reasonably available ..."

Response: The EPA agrees with the commenter; however, as

was explained earlier in this document, proposed §63.1420(h)(3)

is §63.1420(h)(4) in the final rule, and this paragraph

(§63.1420(h)) in the final rule does refer to “paragraphs (h)(1)

through (3)”. 

2.16.43 Table 1

Comment: One commenter (IV-D-07) offered several corrections 

to the subpart PPP cross-references (citations) with subpart A

(Part 63 General Provisions), as well as some editorial

corrections to Table 1 of the proposed rule. 

Response: The EPA appreciates these comments, and revised

Table 1 accordingly.

2.16.44 Table l

Comment: One commenter (IV-D-04) requested that EPA make the

following corrections to Table l in the proposed rule:
2-212

1. In the entry for §63.1(a)(3), change the comment to say

"... which overlap with the requirements of subparts PPP and H

and specify how compliance shall be achieved." Also, if EPA

accepts this comment to add paragraphs dealing with overlaps for

wastewater and heat exchanger provisions, the comment should

begin as follows: "Section 63.1422(f) through (k) of this subpart

...."

2. In the entry for §63.6(e)(3)(i), instead of saying

"combustion, recovery, or recapture devices," the comment should

say "control devices." This would be consistent with subpart U,

and "control devices" would automatically include all combustion,

recovery or recapture devices that are used for emission control.

3. In the entry for §63.7(a)(2), the phrase "compliance

demonstration test results" should be changed to "compliance

demonstration results," deleting the word "test." Subpart H does

not require performance tests.

4. The entry for §63.7(e)(1) currently says performance

tests must be conducted at "maximum representative" operating

conditions, which is inconsistent with the wording of the

proposed rule, which specifies "worst-case" operating conditions.

5. In the entry for §63.7(g), the comment should say

"equipment leaks" subject to §63.1434, rather than "emission

points" subject to §63.1434. This would be consistent with other

entries in the table.

6. In the entry for §63.7(h), the comment should refer to

§63.7(c)(2), not 63.7(c)(3).

Response: All six of the commenter's suggested corrections

were incorporated into the final rule.

2.16.45 Table 2

Comment: One commenter (IV-D-07) offered several corrections

to the subpart PPP cross-references (citations) to subparts F, G
2-213

and H of the HON, as well as some editorial corrections to Table

2 of the proposed rule.

Response: The EPA appreciates these comments, and has

revised Table 2, as necessary.

2.16.46 Table 2

Comment: One commenter (IV-D-04) requested that EPA make the

following changes in Table 2 of the proposed rule:

1. At the end of the comment for subpart H §§63.160-63.193,

add the phrase, "with the differences noted in §63.1434." 

2. In the "reference" column of the entry for subpart H,

instead of saying §§63.160-63.193, it should say §§63.160-63.182. 

There are no sections after §63.182 in subpart H.

Response: The Agency appreciates the comments, and made the

revisions to the final rule.

2.16.47 Table 4

Comment: One commenter (IV-D-05) stated that the footnote in

Table 4 of the proposed rule should read "CAS No. = Chemical

Abstracts Service Registry Number."

Response: The EPA agrees and the final rule was corrected,

as suggested.

2.16.48 Table 5

Comment: One commenter (IV-D-04) requested that EPA make the

following changes in Table 5 of the proposed rule: 

1. In the entry for "Thermal Incinerator," in the third

column, the first item should not say section "63.1429b;" the

letter "b" should be a superscript, referring to a footnote.

2. All entries should be subdivided into requirements for

"continuous" process vents, and requirements for "batch" process

vents. Otherwise, one could interpret that continuous process
2-214

vents are exempt from all requirements, which is not consistent

with the rule.

3. In the entry for "Carbon Adsorber," column 3, item #3

currently says "or volumetric mass flow" but it should say "mass

or volumetric flow."

Response: The EPA agrees with all three comments, and has

made the suggested revisions. However, in lieu of “subdividing”

the requirements in Table 5 into those for process vents from

continuous unit operations and those for process vents from batch

unit operation, the final rule contains a separate table (Tables

5 and 6) for each set of requirements. Table 5 lists the

monitoring, recordkeeping, and reporting requirements for process

vents from batch unit operations, while the new Table 6 lists the

monitoring, recordkeeping, and reporting requirements for process

vents from continuous unit operations.

2.17 LEGAL CONSIDERATIONS

2.17.1 Executive Order 12866

Comment: One commenter (IV-D-04) disagreed with EPA’s

determination that the proposed polyether polyols rule was not a

"significant regulatory action" for purposes of OMB review under

Executive Order 12866. The commenter stated that a regulatory

action is "significant" if it raises "novel legal or policy

issues arising out of legal mandates, the President’s priorities,

or the principles set forth in Executive Order 12866." The

commenter claimed that the proposed rule raises novel legal or

policy issues, including at least the following:

1. Whether Facility M should be considered a "similar"

source, and thus be counted as the floor for new-source MACT,

despite having a very different manner of operation from other

sources that the EPA has considered (with resulting differences

in the amount and pattern of emissions and in the achievable

degree of emission reduction).
2-215

2. Whether a "new source" HAP reduction of 99.9 percent

should be required, when previous MACT standards have uniformly

made a policy decision to consider all combustion devices as no

more than 98 percent efficient.

3. Whether to require monitoring (and associated

recordkeeping and reporting) during start-ups, shutdowns and

malfunctions, even though the "normal" emission control

requirements, which the monitoring is intended to track do not

apply during those periods.

4. Whether to require group determinations for

"combinations" of process vents, despite the fact that the

criteria for determining Group 1 or Group 2 status were tailored

to the characteristics of individual process vents. 

5. Whether to incorporate future changes to the General

Provisions (and perhaps future changes to other standards on

which various portions of this rule are based) without further

rulemaking, in apparent violation of the Administrative

Procedures Act and its Clean Air Act counterpart.

6. Whether the rule may permissibly omit a lower

concentration cutoff (such as 20 ppmv) when compliance with a

percentage HAP reduction limit cannot be demonstrated or

achievable at some HAP feed concentrations.

7. Whether the rule may classify parameter monitoring

excursions as violations of "the emission limitation," rather

than as violations of an operating requirement, even though

parameter monitoring data are incapable of directly demonstrating

compliance or noncompliance with an emission limitation.

For these reasons, the commenter requested that EPA classify

this rule as a "significant regulatory action" for purposes of

OMB review.

Response: The EPA stands by its original determination that

the proposed polyether polyols rule was not a "significant

regulatory action" since it does not raise "novel legal or policy
2-216

issues." The actions raised by the commenter are technical in

nature, and do not introduce any novel legal or policy issues. 

In the first issue, the commenter questioned whether

Facility M (the facility upon whose process vent control the MACT

level of control for new sources was originally based) is a

"similar" source to others in the source category. The commenter

stated that Facility M has a "very different manner of operation

from other sources that the EPA has considered, with resulting

differences in the amount and pattern of emissions and in the

achievable degree of emission reduction." This comment was

addressed in more detail in Section 2.4.1. 

The commenter's second comment addressed whether a new

source HAP reduction of 99.9 percent should be required, when

previous MACT standards "have uniformly made a policy decision to

consider all combustion devices as no more than 98 percent

efficient." This was not a policy decision, but a technical

issue, addressed in Section 2.4.1.

The third "novel legal or policy issue" brought up by the

commenter pertained to the EPA's decision to require monitoring

during start-ups, shutdowns and malfunctions. The EPA does not

believe that monitoring requirements are not legal or policy

issues, which was addressed in Sections 2.4.4 and 2.4.16.

The fourth issue that the commenter considered to be a

"legal or policy issue" discussed the appropriateness of basing 

the group determinations on a combination of process vents,

despite the fact that the criteria for Group 1 or Group 2 status

in the proposed rule based on the characteristics of individual

process vents. The EPA also maintains that this is a technical,

and not a legal or policy issue, which was addressed in Section

2.4.4. 

The commenter's fifth "novel legal or policy issue"

addressed whether to incorporate future changes to the General

Provisions into subpart PPP, without further rulemaking. This is

not a novel legal or policy decision. The commenter contended
2-217

that the automatic incorporation of future changes to the General

Provisions into the subpart PPP requirements would be a violation

of the Administrative Procedures Act (APA) and its Clean Air Act

(CAA) counterpart. The EPA disagrees with this statement because

the any changes made to the General Provisions would have a

public comment period during which parties subject to subpart PPP

would be able to comment.

The commenter's sixth "legal or policy issue" was whether

the rule may permissibly omit a lower concentration cutoff (such

as 20 ppmv) when compliance with a percentage HAP reduction limit

cannot be demonstrated or achievable at some HAP feed

concentrations. The EPA revised the rule to include an

applicable concentration cutoff. Section 2.4.2 of this document

discusses this issue in more detail.

In issue number 7 the commenter questioned whether the rule

may classify parameter monitoring excursions as violations of

"the emission limitation," rather than classifying them as

violations of an operating requirement. Again, this is not a

legal or policy issue and is addressed in section 2.14.4. 
TECHNICAL REPORT DATA

(Please read Instructions on reverse before completing)

1. REPORT NO. 2. 3. RECIPIENT'S ACCESSION NO.

 EPA-453/R-99-002b

4. TITLE AND SUBTITLE 5. REPORT DATE

 National Emission Standards for Hazardous Air Pollutants May 1999

(NESHAP) for the Polyether Polyols Manufacturing Industry --

Summary of Public Comments and Responses

 

6. PERFORMING ORGANIZATION CODE

7. AUTHOR(S) 8. PERFORMING ORGANIZATION REPORT NO.

 

 

9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT NO.

 Emission Standards Division (Mail Drop 13)

 Office of Air Quality Planning and Standards

 U.S. Environmental Protection Agency

 Research Triangle Park, NC 27711

11. CONTRACT/GRANT NO.

 68-D6-0010

12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED

 Director 

 Office of Air Quality Planning and Standards

 Office of Air and Radiation

 U.S. Environmental Protection Agency

 Research Triangle Park, NC 27711

14. SPONSORING AGENCY CODE

 EPA/200/04

15. SUPPLEMENTARY NOTES

 

16. ABSTRACT

 This document contains a summary of public comments received on the NESHAP for Polyether Polyols

Production (40 CFR 63, subpart PPP), which was proposed on September 4, 1997 (62 FR 46804). This

document also provides the EPA’s response to each comment, and outlines the changes made to the

regulation in response to public comments.

17. KEY WORDS AND DOCUMENT ANALYSIS

a. DESCRIPTORS b. IDENTIFIERS/OPEN ENDED TERMS c. COSATI Field/Group

 Air Pollution Hazardous air pollutants

 Hazardous air pollutants

 Emission reduction

 Polyether Polyols

18. DISTRIBUTION STATEMENT 21. NO. OF PAGES

 Release Unlimited

19. SECURITY CLASS (Report)

 Unclassified 238

20. SECURITY CLASS (Page)

 Unclassified

22. PRICE

EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION IS OBSOLETE