National Emission Standards for Hazardous Air Pollutants 

from the Pulp and Paper Industry (40 CFR Part 63, Subpart S)

Residual Risk and Technology Review, Final Amendments

Response to Public Comments on

December 27, 2011 Proposal

U.S. Environmental Protection Agency

Office of Air Quality Planning and Standards

Sector Policies and Programs Division

Research Triangle Park, NC 27711

July 31, 2012
ii

Table of Contents

Page

1. Introduction................................................................................................................................. 1

2. Summary of Changes since Proposal.......................................................................................... 2

3. Summary of Public Comments................................................................................................... 3

4. Risk Assessment ......................................................................................................................... 5

4.1 Risk Assessment Inputs.................................................................................................... 5

4.1.1 Processing of ICR Data into Modeling File ................................................................. 5

4.1.2 Changes to Mill-specific NEI Data .............................................................................. 8

4.2 Risk Assessment Methods................................................................................................ 9

4.2.1 Modeling of MACT Allowable Emissions................................................................. 13

4.2.2 Modeling of Facilitywide Emissions.......................................................................... 15

4.2.3 Modeling of Acute Exposure...................................................................................... 17

4.2.4 Multipathway Screening............................................................................................. 22

4.2.5 Dose-response Benchmarks........................................................................................ 27

4.3 Uncertainties in Risk Assessment .................................................................................. 39

4.4 Risk Assessment Results................................................................................................ 41

4.5 Demographics................................................................................................................. 60

5. Technology Review .................................................................................................................. 66

5.1 EPA’s Authority under CAA Section 112(d)(6)............................................................ 68

5.3 Bleaching Standards....................................................................................................... 72

5.4 Kraft Pulping Condensate Standards.............................................................................. 74

5.4.1 General Comments on the Kraft Pulping Condensate Standards............................... 74

5.4.2 Technology, Proposed Numerical Limits, and Variability Associated with Kraft 

Condensate Collection and Treatment..................................................................................... 79

6. Unregulated Sources............................................................................................................... 102

7. Startup, Shutdown, and Malfunction ...................................................................................... 105

7.1 Authority for Removal of the SSM Exemption ........................................................... 105

7.2 Startup and Shutdown .................................................................................................. 114

7.3 Malfunction and Affirmative Defense ......................................................................... 127

8. Excess Emissions Allowances................................................................................................ 157

8.1 LVHC Systems (1 Percent).......................................................................................... 170

8.2 HVLC Systems (4 Percent).......................................................................................... 171

8.3 Steam Stripper Systems (10 Percent)........................................................................... 172

9. Testing and Monitoring........................................................................................................... 174

9.1 Repeat Testing.............................................................................................................. 175

9.2 Emissions Test Methods............................................................................................... 177

9.3 Electronic Reporting .................................................................................................... 178

10. Compliance Dates................................................................................................................. 183

11. Regulatory Impacts............................................................................................................... 186

12. Miscellaneous Comments..................................................................................................... 195

12.1 Commenter Endorsements........................................................................................ 195

12.2 Other Comments....................................................................................................... 195

Appendix A. Mills Providing NEI Revisions............................................................................. A-1
iii

List of Tables

Page

Table 1. List of Commenters on 40 CFR Part 63 Subpart S, Proposed December 27, 2011

(76 FR 81328)................................................................................................................................. 4

Table 2. Comparison of Emission Rates in EPA’s Documents with Each Other and with

Those Found in 2005 and 2009 Toxics Release Inventories .......................................................... 5

Table 3. Acute Multipliers by Emission Process Group for Risk Modeling for Subpart S

(MACT Code 1626-1)................................................................................................................... 21

Table 4. Comparison of Acrolein RfC Used by Various Government Organizations.................. 31

Table 5. Data on Methanol Collection and Percent of Time below De Facto Proposed

Collection Standard from Georgia-Pacific Kraft Mills................................................................. 90

Table 6. Kraft Condensate Treatment Standards Considered for Promulgation .......................... 90

Table 7. Over-Collection Levels to Demonstrate Compliance with lb/ODTP Collection 

Requirements ................................................................................................................................ 96

Table 8. Condensate Collection Characteristics at Four Kraft Mills............................................ 96

Table 9. Capital Cost Estimate for Redundant Systems............................................................. 168

Table 10. Costs of Proposed Condensate Treatment Standards ................................................. 187

Table 11. Summary of Nationwide Costs and Cost Effectiveness for the Kraft Condensate 

Regulatory Options..................................................................................................................... 192

Table 12. Summary of Estimated Nationwide Environmental and Energy Impacts.................. 192

List of Figures

Page

Figure 1. EPA Calculation Methodology..................................................................87

Figure 2. AF&PA Recommended Calculation Methodology..........................................88
iv

List of Acronyms and Units of Measure

AAL Acceptable Ambient Level

ACC American Chemistry Council

Act Clean Air Act

ADTBP Air-Dried Ton of Bleached Pulp

ADTUBP Air-Dried Ton of Unbleached Pulp

AEGL Acute Exposure Guideline Level

AERMOD AMS and EPA’s AERMIC Model

AF&PA American Forest & Paper Association

AFS EPA’s Air Facility System

AIRS EPA’s Aerometric Information Retrieval System

AMOS Ample Margin of Safety

AOX Adsorbable Organic Halides

APPCO Alabama Pulp & Paper Council

ASB Aerated Stabilization Basin

AST Activated Sludge Treatment

BACT Best Available Control Technology

BART Best Available Retrofit Technology

BAT Best Available Technology Economically Achievable

BBDR Biologically-Based Dose-Response

BID Background Information Document

BL Black Liquor

BLO Black Liquor Oxidation

BMS Burner Management System

BOD5 5-Day Biochemical Oxygen Demand

CAA Clean Air Act

CalEPA California Environmental Protection Agency

CCA Clean Condensate Alternative

CDC Centers for Disease Control and Prevention

CDX EPA’s Central Data Exchange

CEDRI EPA’s Compliance and Emissions Data Reporting Interface

CEMS Continuous Emissions Monitoring System

CFD Computational Fluid Dynamic (Model)

CFR Code of Federal Regulations

CH4 Methane

CIIT Chemical Industry Institute of Technology

Cl2 Chlorine

ClO2 Chlorine Dioxide

CO Carbon Monoxide

CO2 Carbon Dioxide

CO2eq CO2 Equivalents

Court United States Court of Appeals for the District of Columbia Circuit

Cr+3 Trivalent Chromium

Cr+6 Hexavalent Chromium

CROMERR Cross Media Electronic Reporting Rule
v

CRWI Coalition for Responsible Waste Incineration

CWA Clean Water Act

DC District of Columbia

D.C. Cir. United States Court of Appeals for the District of Columbia Circuit

dL Deciliter(s)

DPX DNA-Protein Cross-Link

EBP Equivalency by Permit

ECF Elemental Chlorine Free

ECHO EPA’s Enforcement and Compliance History Online

EMS Environmental Management System

EO Executive Order

EPA Environmental Protection Agency

ERPG DOE’s Emergency Removal Program Guidelines

ERT Electronic Reporting Tool

ESA Endangered Species Act

EU Emission Unit, European Union

FAX Facsimile

Fbio Site-Specific Fraction of VOC Biodegraded

FIP Federal Implementation Plan

FQPA Food Quality Protection Act

FR Federal Register

GHG Greenhouse Gas

GP General Provisions

HAD EPA’s Health Assessment Document

HAP Hazardous Air Pollutant

HCE Hexachloroethane

HD High-Density

HEM/HEM3 EPA’s Human Exposure Model

HI Hazard Index

HL Hodgkin Lymphoma

HON Hazardous Organic NESHAP

HQ Hazard Quotient

hr Hour(s)

HVLC High Volume Low Concentration

ICAC Institute of Clean Air Companies

ICR Information Collection Request

IPPC European Commission’s Integrated Pollution Prevention and Control

IPT Initial Performance Test

IQA Information Quality Act

IRIS EPA’s Integrated Risk Information System

LAER Lowest Achievable Emission Rate

lb Pound(s)

LD Low-Density

LEL Lower Explosive Limit

LEU Leukemia

LK Lime Kiln
vi

LOAEL Lowest Observed Adverse Effect Level

LVHC Low Volume High Concentration

m

3 Cubic Meter(s)

MACT Maximum Achievable Control Technology

MACT Code Code within the NEI used to identify processes included in a source category

MEK Methyl Ethyl Ketone

mg Milligram(s)

MIBK Methyl Isobutyl Ketone

MIR Maximum Individual Risk

MLVSS Mixed Liquor Volatile Suspended Solids

MOE Ontario Ministry of the Environment

MW Megawatt(s)

N2O Nitrous Oxide

NAAQS National Ambient Air Quality Standards

NACAA National Association of Clean Air Agencies

NAS National Academy of Sciences

NATA National-Scale Air Toxics Assessment

NCASI National Council for Air and Stream Improvement

NCDENR North Carolina Department of Environment and Natural Resources

NCG Non-Condensable Gas

NCSAB North Carolina Science Advisory Board for Toxic Air Pollutants

NEI National Emissions Inventory

NIOSH National Institute for Occupational Safety and Health

NESHAP National Emissions Standards for Hazardous Air Pollutants

NOAEL No Observed Adverse Effect Level

NOX Nitrogen Oxides

NPC Nasopharyngeal Cancer

NPDES National Pollutant Discharge Elimination System

NRDC Natural Resources Defense Council

NSPS New Source Performance Standards

NSSC Neutral Sulfite Semichemical

NYC New York City

NYDEC New York Department of Environmental Conservation

O2Delig Oxygen Delignification

OAQPS EPA’s Office of Air Quality Planning and Standards

OCC Old Corrugated Cardboard

ODP Oven-Dried Pulp

ODTP Oven-Dried Ton(s) of Pulp

ODW EPA’s Office of Drinking Water

OECA EPA’s Office of Enforcement and Compliance Assurance

OEHHA California EPA’s Office of Environmental Health Hazard Assessment

OGC EPA’s Office of General Counsel

OHEA EPA’s Office of Health and Environmental Assessment

OMB Office of Management and Budget

ORP Oxidation/Reduction Potential

OSWER EPA’s Office of Solid Waste and Emergency Response
vii

PAH Polycyclic Aromatic Hydrocarbon

PB Power Boiler

PB-HAP Persistent and Bioaccumulative HAP

PCA Packaging Corporation of America

PCB Polychlorinated Biphenyl

PM Particulate Matter

POM Polycyclic Organic Matter

ppbdv Part(s) per Billion by Volume, Dry Basis

ppm Part(s) per Million

ppmv Part(s) per Million by Volume

ppmw Part(s) per Million by Weight

ppt Part(s) per Trillion

PRA Paperwork Reduction Act

PSD Prevention of Significant Deterioration

PT Port Townsend

PTPC Port Townsend Paper Corporation

PV Pressure/Vacuum

QA Quality Assurance

QC Quality Control

R2C Residual Risk Coalition

RACT Reasonably Available Control Technology

RATA Relative Accuracy Test Audit

RBLC RACT/BACT/LAER Clearinghouse

RCP Regenerative Cellular Proliferation

REL CalEPA’s Reference Exposure Level, NIOSH’s Recommended Exposure Level

RF Recovery Furnace

RfC Reference Concentration

RfD Reference Dose

rpm Revolutions per Minute

RSD Relative Standard Deviation

RTR Residual Risk and Technology Review

S. Ct. United States Supreme Court

SAB EPA’s Science Advisory Board

SCC Source Classification Code

SD Standard Deviation

SDT Smelt Dissolving Tank

SFR Steam-to-Feed Ratio

SIP State Implementation Plan

SO2 Sulfur Dioxide

SOCMI Synthetic Organic Chemical Manufacturing Industry

SOG Stripper Off-Gas

SSM Startup, Shutdown, and Malfunction

TCDD Tetrachlorodibenzo(p)dioxin

TCF Totally Chlorine Free

TOSHI Target Organ-Specific Hazard Index

tpy Ton(s) Per Year
viii

TRIM.FaTE EPA’s Total Risk Integrated Methodology, Environmental Fate, Transport, and

Ecological Exposure Module

TRS Total Reduced Sulfur

TTN EPA’s Technology Transfer Network

UEL Upper Explosive Limit

URE Unit Risk Estimate

U.S. United States

U.S.C. United States Code

v. Versus

VOC Volatile Organic Compound

WWT Wastewater Treatment

WWTP Wastewater Treatment Plant

WWTS Wastewater Treatment System

WWW Worldwide Web

μg Microgram(s)
1

1. Introduction

Section 112(f)(2) of the Clean Air Act (CAA) directs the U.S. Environmental Protection 

Agency (EPA) to conduct risk assessments on each source category subject to maximum 

achievable control technology (MACT) standards and determine if additional standards are 

needed to reduce residual risks within 8 years after promulgation. Section 112(d)(6) of the CAA 

requires EPA to review and revise the MACT standards, as necessary, taking into account 

developments in practices, processes, and control technologies at least every 8 years. The 

national emission standards for hazardous air pollutants (NESHAP) for the pulp and paper 

industry (40 CFR part 63, subpart S) were promulgated in 1998 and are due for review under 

sections 112(f)(2) and 112(d)(6).

Subpart S is one of several NESHAP included in a January 2009 schedule suit filed by

Sierra Club that asks the D.C. Circuit Court to compel EPA to complete the residual risk and 

technology review (RTR) assessments required by the CAA. The EPA entered into a consent 

agreement which specifies a proposal date of December 15, 2011 and a promulgation date of 

July 31, 2012 for subpart S RTR. In addition, on December 19, 2008, the D.C. Circuit Court 

vacated the startup, shutdown, and malfunction (SSM) exemption provisions in the General 

Provisions (GP) for non-opacity [§63.6(f)(1)] and opacity [§63.6(h)(1)] standards.

To address the RTR assessments and SSM exemptions, proposed amendments to subpart 

S were developed, signed by the EPA Administrator on December 15, 2011, and published in the 

Federal Register on December 27, 2011. A 60-day period ending February 27, 2012 was 

provided for the public to submit comments on the proposal to EPA. A summary of the changes 

made since proposal is presented in the following section.
2

2. Summary of Changes since Proposal

Several changes have been made since proposal of the subpart S amendments. The major 

changes include (1) removing the kraft condensate amendments, (2) clarifying that certain 

subpart S equipment systems are exempted from the repeat testing provisions, (3) clarifying the 

compliance dates for performance testing and electronic reporting, and (4) clarifying that 

asserting an affirmative defense is available when a source violates a standard due to a 

malfunction, as defined at 40 CFR 63.2. We have elected not to remodel risk for promulgation, 

but instead will rely on the conclusions from the risk modeling conducted for the proposed rule. 

We are also deferring final action on the excess emissions allowances until a later date in order 

to analyze more recent information obtained from the industry. The remainder of this document 

summarizes the public comments on the proposal and provides EPA’s responses, which were 

used as the basis for most of the changes made since proposal.
3

3. Summary of Public Comments

The following sections of this document summarize the public comments received on the 

proposal and present EPA’s responses to those comments. A total of 27 separate sets of written 

comments were received on the proposal (in addition to 81 site-specific National Emission 

Inventory (NEI) revisions). See www.regulations.gov, docket ID no. EPA-HQ-OAR-2007-0544, 

for the complete comments. Table 1 below lists the names of the commenters providing written 

comments, their affiliations, and the document numbers assigned to their comments. For 

simplicity, only the last four digits (and decimal, if applicable) of the document numbers specific 

to each commenter are presented in this document (e.g., 0083.1, instead of EPA-HQ-OAR-2007-

0544-0083.1). Commenters providing NEI updates are listed in Appendix A and discussed in 

section 4.1.2 of this document.

The comment summaries are grouped by topic in Sections 4 through 12 as follows:

 Section 4–Risk Assessment 

 Section 5–Technology Review

 Section 6–Unregulated Sources

 Section 7–Startup, Shutdown, and Malfunction

 Section 8–Excess Emissions Allowances

 Section 9–Testing and Monitoring

 Section 10–Compliance Dates

 Section 11–Regulatory Impacts

 Section 12–Miscellaneous Comments

In some cases, one or more commenters endorsed the comments by another commenter. 

In those cases, the endorsement is noted in the “Miscellaneous Comments” section. The 

comment summaries are numbered sequentially (1, 2, 3, etc.) throughout the document, 

regardless of section.
4

Table 1. List of Commenters on 40 CFR Part 63 Subpart S, Proposed December 27, 2011 

(76 FR 81328)

Docket No. 

EPA-HQOAR-2007-

0544 Commenter Name Affiliation

0153 Anonymous Not provided

0154 John Ashley Weyerhaeuser New Bern Mill

0160 Shelia Holman North Carolina Dept. of Environment and Natural 

Resources (NCDENR)

0161, 0161.1 J. Jared Snyder New York Department of Environmental 

Conservation (NYDEC)

0162 Paul Noe American Forest & Paper Association (AF&PA)

0163, 0163.1, 

0163.2

Stephen E. Woock Weyerhaeuser

0164 Russell Frye SSM Coalition

0165 Roy McAuley Alabama Pulp & Paper Council (APPCO)

0167 Dirk J. Krouskop MeadWestvaco Corporation

0168 Melvin E. Keener Coalition for Responsible Waste Incineration (CRWI)

0170 Dave Kiser International Paper

0171 G. Vinson Hellwig and 

Robert H. Colby

National Association of Clean Air Agencies

(NACAA)

0172 Traylor Champion Georgia-Pacific LLC

0174, 0174.2 Paul Dickens and 

Michael Koerschner

Blue Ridge Paper Products Inc. dba Evergreen 

Packaging

0187 Kelly D. Bryant Evergreen Packaging: Pine Bluff Facility

0190 Jeffery Shumaker International Paper (NEI revisions)

0193 Anitra J. Collins KapStone Roanoke Rapids Mill

0195 Richard Holland Packaging Corporation of America (PCA)

0196 Matthew Todd Residual Risk Coalition (R2C)

0198 Keith Wahoske Georgia-Pacific - Port Hudson Operations

0207 Craig Liska Verso Paper Corporation

0208 Ann Mason American Chemistry Council (ACC)

212 Nina E. Butler Rock-Tenn Company

0214 Gretchen Brewer PT AirWatchers

0218 (with 6 

file sets as

attachments: 

0219.1 -

0224.18)

Emma Cheus and James 

Pew, et al.

Earthjustice, Sierra Club, Northwest Environmental 

Defense Center, Concerned Citizens for Clean Air, 

Neighbors for Clean Air, and PT AirWatchers

0225 Gretchen Brewer PT AirWatchers

0228 Melanie Loyzim State of Maine
5

4. Risk Assessment

4.1 Risk Assessment Inputs

4.1.1 Processing of ICR Data into Modeling File

1. Comment: Commenter 0161.1 disagreed with the EPA’s presentation and explanation of 

their methods for arriving at the summary of the hazardous air pollutant (HAP) emission rates 

used in the emissions inventory. This commenter did not think the EPA provided enough 

information to verify the accuracy of their work. In this commenter’s review of the data, they 

constructed Table 2 below to show the inaccuracies they believe are present in information 

released by the EPA.

Table 2. Comparison of Emission Rates in EPA’s Documents with Each Other and with 

Those Found in 2005 and 2009 Toxics Release Inventories

(Submitted by Commenter 0161.1)

State Facility Name

a

Acetaldehyde Emissions (tpy)

RTRb

RTIc

2009 

TRId

2005 

TRIdInitial Final

MI Packaging Corporation of America – Filer City Mill 3.84 59.10 0.89 15.80 17.24

AL Fort James-Pennington 36.92 25.62 6.42 33.00 26.50

SC INTERNATIONAL PAPER:GEORGETOWN MILL 44.37 0.52 7.18 42.56 56.23

AL International Paper Company 96.22 18.90 1.92 77.00 46.45

ID Clearwater Paper Corp – PPD & CPD, Idaho 11.39 51.44 1.52 48.15 47.25

a. The “Facility Name” in the table above is that used in the RTR both in the “RTR Review file” and the RTI 

“Follow-Ups memo.”

b. These emissions data are from the “RTR Review file” which originated with the National Emissions Inventory 

(NEI) data reported to the EPA by the states.

c. These emissions data are from the RTI “Follow-Ups memo” which came from the facilities’ responses to the 

Information Collection Requests (ICRs) sent to them by EPA or RTI.

d. The Toxics Release Inventory (TRI) emission rates are submitted by the facilities directly to EPA.

Specifically, the commenter questioned the following documents as the provision for the 

data:

1. “RTR review file for Pulp and Paper Production Proposal” (“RTR Review file”) file 

found within the Air Toxics Web Site of EPA’s Technology Transfer Network 

(TTN).

2. RTI November 2011 memorandum titled “Summary of Follow-Ups Conducted 

Regarding Residual Risk Modeling Results” (“Follow-Ups memo”) found within the 

docket for the Pulp and Paper Industry NESHAP.

The commenter believes that EPA should explain why the acetaldehyde emissions used 

in this assessment were significantly reduced, when the reported NEI and TRI acetaldehyde 

emissions for these facilities were all within the range for 35 other facilities in this source 

category as reported in the 2009 Toxics Release Inventory (TRI) and the “RTR Review file.”

The RTI “Follow-Ups memo” indicates that the reduction of annual acetaldehyde emissions for 

the RTR assessment was triggered by findings of elevated cancer and non-cancer risk for these 
6

facilities. The commenter questioned whether it was the closer nearby populated receptors that 

drove the higher risks predicted from these five facilities, not any suspiciously high emission 

rates, as stated in the RTI “Follow-Ups memo.”

Response: The follow-ups memo cited by the commenter only presents the inventory

changes that EPA received from mills in response to EPA’s inquiries (i.e., inventory changes for 

those particular emission units whose emissions data were undergoing review/revision).1The 

particular emission units with emissions undergoing revision are noted in the emission unit 

columns of Tables 1 and 2 of the follow-ups memo. The follow-ups memo does not include millwide totals, which are what the commenter has included in the RTR column and TRI columns in 

the table he provided with his comment. So, the commenter is actually comparing acetaldehyde 

emissions for the entire mill (in the RTR and TRI columns) to acetaldehyde emissions from one

or more emission units (in the RTI columns) whose data were undergoing review/revision, which 

explains the large discrepancy in emissions. To clarify further, the emissions estimates in the 

RTR column are based on inventory updates provided by the mills in their responses to the 2011 

information collection request (ICR) (using NEI data reported by the states as the baseline from 

which to provide their updates), corrected using the emissions data revisions in the RTI Final 

column. Regarding the commenter’s concerns about the reasons for the emissions reductions, 

there were a number of valid reasons for the reductions, as described in the paragraphs below.

The erroneous acetaldehyde emissions for the PCA mill were discovered when EPA 

reviewed the preliminary chronic cancer risk results for the pulp and paper industry. The EPA 

had a concern regarding the acetaldehyde emissions from the wastewater treatment plant at the 

PCA mill, specifically the primary clarifier (EU ID WWTP1) and aerated lagoons (EU IDs 

WWTP2 and WWTP3). The 59.1 tons per year (tpy) estimate for acetaldehyde was the highest 

for the pulp and paper industry for this type of emission unit (wastewater) and nearly 50 times 

higher than the next highest semichemical mill for this type of emission unit. The EPA asked the 

mill to take another look at the acetaldehyde emissions for these emission units and verify the 

accuracy of the data. In their response, the mill said that they had an error in their spreadsheet 

calculation on the throughput multiplier for wastewater emissions—they multiplied by the wrong 

cell number.

The erroneous acetaldehyde emissions for the Georgia-Pacific Naheola mill (in 

Pennington, AL) were discovered by the mill in the process of responding to EPA inquiries 

regarding unusually high emissions from the Kamyr digester, washers, screens, smelt dissolving 

tank, and recovery furnace at the mill. In their review of the data, the mill noted that the Kamyr 

digester exhaust is collected and conveyed to the permitted destruction sources at the mill, so 

there are no direct emissions of any pollutant for the Kamyr digester (i.e., emissions from the 

Kamyr digester are zero). The mill also used the opportunity to update the emissions from the 

other sources and provided documentation to support their re-calculated emissions.

The erroneous acetaldehyde emissions for the International Paper-Georgetown mill were 

discovered by the mill in the process of reviewing all of their inventory data after receiving an 

 

1

See memorandum from T. Holloway and K. Hanks, RTI, to J. Bradfield and B. Schrock, EPA, titled Summary of 

Follow-Ups Conducted Regarding Residual Risk Modeling Results, November 28, 2011, in the docket for the 

subpart S rulemaking.
7

inquiry from EPA regarding the tetrachloroethylene emissions from the clarifier (EU ID 

WWAER1) at the mill. In the process of reviewing the tetrachloroethylene data, the mill 

discovered incorrect emissions data for three other pollutants (acetaldehyde, methanol, and 

formaldehyde) from both the clarifier (EU ID WWAER1) and aerated stabilization basin (ASB)

(EU ID WWAER2). According to the mill’s consultant, the source of the incorrect data appears 

to have occurred during export of the data from the facility’s data management system, resulting 

in the compounds and emissions rates being extracted and incorporated into the spreadsheet 

incorrectly.

The erroneous acetaldehyde emissions for the International Paper-Prattville mill were 

discovered by the mill in reviewing their Part II inventory data with the assistance of the 

National Council for Air and Stream Improvement (NCASI). According to the mill, the error in 

the acetaldehyde value for the ASB (EU ID WWTASB) appeared to be a transcription error.

The erroneous acetaldehyde emissions for the Clearwater Paper-Lewiston mill were 

discovered by the mill in the process of reviewing all of their inventory data after receiving an 

inquiry from EPA regarding the acrolein emissions from the wastewater treatment system (EU 

ID PR13) at the mill. According to the mill, a calculation error was made while updating the 

emissions for acetaldehyde and other HAPs for paper machines and pulp dryers; a correction was 

also made for emissions from wastewater treatment for all HAPs.

2. Comment: Commenter 0174 submitted (in attachment 0174.2) emission factor guidance 

developed by NCASI and distributed to member companies in June 2011, entitled “Additional 

Information on Acetaldehyde, Formaldehyde, and Acrolein Emissions from Paper Machines and 

Pulp Dryers Located at Bleached Kraft Mills.”

Response: We acknowledge receipt of the emission factor guidance distributed by

NCASI.

3. Comment: Commenter 0195 stated that limitations and errors in the input data and in the 

modeling methods used may still affect the ability of the RTR assessment to accurately 

characterize maximum off-site risk. The commenter expected that a more accurate and detailed 

characterization of emissions sources for their facility would result in lower, more realistic risk 

estimates. The commenter stated that independent verification of EPA’s modeling was not 

available to the facility. 

Response: The commenter’s concerns about the limitations and errors in the modeling 

methods and the inability to independently verify EPA’s modeling are addressed in our response 

in section 4.2 below, relating to Human Exposure Model (HEM) methodology. Regarding the 

commenter’s concerns about the limitations and errors in the input data and the need for a more 

accurate and detailed characterization of emissions sources, we would expect the commenter’s 

company to provide NEI data revisions to help us refine the inventories for their mills (if

needed). The EPA issued a request for comment in the December 27, 2011 proposal asking for 

such corrections to the mill-specific HAP emissions data used in the risk modeling.

We have received and reviewed the post-proposal NEI data revisions that the 

commenter’s company submitted for its Valdosta mill in Clyattville, GA and its Counce mill in 
8

Counce, TN. The Valdosta mill provided no revisions to its subpart S sources (MACT code 

1626-1). All of the revisions for this mill relate to its subpart MM chemical recovery sources 

(MACT code 1626-2), specifically deleting all smelt dissolving tanks (SDTs) and recovery

furnaces currently in the mill’s inventory since they have been replaced with new units. No 

emissions data for the replacement units were provided, since initial test data for these units are 

not yet available. The Counce mill provided revisions to the data for its paper machines, black 

liquor storage tanks, and wastewater treatment system, which we have reviewed. No postproposal NEI data revisions were received for the commenter’s mills in Filer City, MI and 

Tomahawk, WI. The data revisions for the Valdosta and Counce mills are accounted for in a

memo for the docket that summarizes the post-proposal NEI revisions for the pulp and paper 

industry in the context of determining whether or not to remodel risk.2

4.1.2 Changes to Mill-specific NEI Data

4. Comment: A number of mills submitted specific revisions to their NEI risk input files.

Appendix A at the end of this document lists the mills providing NEI revisions.

Response: The NEI revisions were reviewed to determine whether they would influence 

the outcome of the proposed risk assessment results. Based on our review, we have concluded 

that the results of remodeling risk would most likely adjust the risk results for the subpart S 

source category downward (i.e., reduce risk). Because of this, EPA has elected not to remodel 

risk for purposes of promulgating of the subpart S residual risk review, but instead to rely on the 

conclusions from the risk modeling conducted for the proposed rule. A memo for the docket has 

been prepared summarizing the NEI revisions, noting their likely effect on risk, and documenting 

the recommendation not to remodel risk.3

5. Comment: Commenter 0162 attached a February 24, 2012 memorandum from NCASI

relating to hexachloroethane (HCE) emissions from brownstock washers and bleach plant 

sources (see Attachment 3 to comment 0162).

4

Through this attachment, commenter 0162 stated 

that there is significant uncertainty about the isolated detect data for HCE from brownstock 

washers and bleach plant sources. The commenter noted that many facilities used emission 

factors from NCASI’s Air Toxics Database to estimate HCE emissions from these sources and 

said that these NCASI emission factors were based upon limited test data from 1993, most of 

which were non-detects. According to the commenter, HCE was detected in one diffusion 

washer vent at a bleached pulp mill and not detected at three vacuum-drum washer systems 

(eleven total vents) at two bleached pulp mills. In addition, the commenter noted that HCE 

emissions were detected in one elemental chlorine free (ECF) bleach plant scrubber vent but not 

detected in six non-ECF bleach plant systems. Commenter 0162 stated that HCE is not a known 

pulping byproduct, and the conditions for its formation are not expected to exist either in 

brownstock washer systems or in bleach plant systems. The commenter noted that NCASI is 

planning to perform additional emissions testing of several vents from a vacuum drum washer 

 

2

See memorandum from T. Holloway, RTI, to J. Bradfield, B. Schrock, K. Spence, and N. Swanson, EPA, titled 

Recommendations Concerning Residual Risk Remodeling for the Pulp and Paper Industry, November 28, 2011, in 

the docket for the subpart S rulemaking.

3

Id.

4

See memorandum from Z. Emerson, NCASI, to file, titled Hexachloroethane Emissions from Brownstock Washers 

and Bleach Plant Sources, February 24, 2012.
9

system, a diffusion washer system, and a bleach plant scrubber to confirm the expected absence 

of HCE.

Response: Several mills submitting NEI revisions also submitted a copy of the NCASI

memo, as noted in section 12.1 below. To resolve questions in the memo about the presence of 

HCE emissions from brownstock washers and bleach plant sources, NCASI conducted additional 

HCE emissions testing (as noted in the comment above) at these mill sources. The EPA has 

received a summary of the results of the NCASI testing, which provided the following 

information.

 At the vacuum drum washer, HCE was detected in all three sample runs at a detection 

limit significantly lower than that achievable with EPA Method 18. The average emission 

factor developed for the test was 1.32E-05 pounds per air-dried ton of unbleached pulp 

(lb/ADTUBP), which NCASI estimated to be three orders of magnitude lower than the 

previous, pre-MACT emission factor based on non-detect values at the analytical 

detection limit.

 At the diffusion washer, HCE was not detected in any of the three sample runs. In-stack 

detection limits for this testing ranged from 9.7 to 12.4 parts per billion by volume, dry

basis (ppbdv), resulting in an average emission factor of less than 3.48E-06 lb/ADTUBP.

 At the ECF bleach plant scrubber vent, HCE was not detected in any of the three sample 

runs. In-stack detection limits for this testing ranged from 9.6 to 11.3 ppbdv, resulting in 

an average emission factor of less than 1.16E-04 lb/ADTBP.

Based on our review of these test results, we conclude that HCE is not emitted from 

diffusion washers and bleach plant scrubbers. Furthermore, since HCE has been found to be 

emitted from vacuum drum washers at much lower levels than previously reported (which were 

themselves based on non-detect values at the analytical detection limit), we conclude that the 

current NEI emission estimates for HCE from vacuum drum washers are not representative of 

actual emissions. Therefore, we have decided to accept the request for removal of HCE from 

brownstock washers and bleach plants in the mill inventories. To that end, HCE emissions data 

have been removed from the brownstock washers and bleach plants in the inventories of the 26 

mills that submitted NEI revisions requesting the removal of the pollutant.

4.2 Risk Assessment Methods

6. Comment: Census Block vs. Fenceline. Commenter 0218 argued that the EPA’s

modeling understates cancer and other chronic health risk by assuming that chronic exposure to 

HAPs from each source occurs at the census block centroid and not at the facility fence or 

property line. The commenter expressed concern that, by declining to assess cancer and chronic 

non-cancer risk at the fence line, EPA’s analysis fails to consider the actual level of risk for the 

“individual most exposed to emissions,” as required by section 112(f). Estimating the annual 

average concentrations at the area-weighted centers of census blocks artificially underestimates 

the risk estimated for people at the fence line, since the center of a census block will almost 

always be further away from the facility than its fence line. Census blocks vary greatly in size, 

especially in less populated areas. As EPA admits, area-weighted centers of census blocks are 
10

likely to underestimate exposure in some cases because they “under-predict exposures for people 

in the census block who live closer to the facility.” The commenter supported the EPA’s decision 

to make exceptions, placing additional residential receptors where there were observable 

residences when census blocks were abnormally large, but wonders how the residences were 

identified, observing that EPA used out–of-date 2000 census data and satellite images may not 

provide reliable information. The commenter noted that the EPA adjusted receptor points in the 

HEM-AERMOD system to estimate acute health risks for residents living on the fence line. The 

commenter concludes that failing to assess risk at the fence would be unlawful, arbitrary, and 

capricious as such an approach fails to assess risk for the person “most exposed” to the source 

category’s emissions.

Response: As we have noted in the development of previous residual risk regulations, 

such as the Hazardous Organic NESHAP (HON), in a national-scale assessment of lifetime 

inhalation exposures and health risks from facilities in a source category, it is appropriate to 

identify exposure locations where it may be reasonably expected that an individual will spend a 

majority of his or her lifetime. Further, in determining chronic risks, it is appropriate to use 

census block information on where people actually reside, rather than points on a fence line, to 

locate the estimation of exposures and risks to individuals living near such facilities. Census 

blocks are the finest resolution available as part of the nationwide population data (as developed 

by the U.S. Census Bureau); each is typically comprised of approximately 40 people or about 10 

households. In EPA risk assessments, the geographic centroid of each census block containing at 

least one person is used to represent the location where all the people in that census block live. 

The census block centroid with the highest estimated exposure then becomes the location of 

maximum exposure, and the entire population of that census block is assumed to experience the 

maximum individual risk. In some cases, because actual residence locations may be closer to or 

farther from facility emission points, this may result in an overestimate or underestimate of the 

actual annual concentrations (although there is no systematic bias for average levels). Given the 

relatively small dimensions of census blocks in densely-populated areas, there is little 

uncertainty introduced by using the census block centroids. There is more uncertainty when 

census blocks are larger, although there is still no systematic bias. Thus, the EPA concludes that 

the most appropriate locations at which to estimate chronic exposures and risks are the census 

block centroids because: (1) census blocks are the finest resolution available in the national 

census data, (2) facility fence lines do not typically represent locations where chronic exposures 

are likely (i.e., people do not typically live at the fence line of facilities), and (3) as just described 

above, there is no systematic bias with respect to using census block centroids as an exposure 

surrogate for all individuals residing in that block.

This has been EPA’s approach for estimating chronic maximum individual exposures and 

risks throughout the RTR program. In its peer review of the methodologies used to estimate risks 

as part of the RTR rulemaking efforts, the EPA’s Science Advisory Board (SAB) endorsed this 

approach. In addition, the commenter is correct that EPA did not model population risks based 

upon the 2010 census data; at the time of modeling, the 2010 census data were not fully available 

and verified to ensure an accurate location of the modeled population receptors. To reduce our 

uncertainities in estimating population risks for census blocks with centroids located on the 

facility boundaries, EPA relocated the centroid to an off-site residential location. In these cases 

and the case when the census block was extremely large, EPA moved and added receptors to 

improve our risk characterization. These additional receptors were identified using satellite 
11

imagery provided by Google Earth. The EPA believes there are opportunities for both under- and 

over-estimating risk, based upon our modeling assumptions. Notably, uncertainties are described 

in section 4.1 of the risk assessment document. In part, this section states:

If anything, the population exposure estimates are biased high by not accounting for 

short- or long-term population mobility, and by neglecting processes like deposition, 

plume depletion, and atmospheric degradation. Additionally, estimates of the maximum 

individual risk (MIR) contain uncertainty, because they are derived at census block 

centroid locations rather than actual residences. This uncertainty is known to create 

potential underestimates and overestimates of the actual MIR values for individual 

facilities, but, overall, it is not thought to have a significant impact on the estimated MIR 

for a source category. Finally, we did not factor in the possibility of a source closure 

occurring during the 70-year chronic exposure period, leading to a potential upward bias 

in both the MIR and population risk estimates; nor did we factor in the possibility of 

population growth during the 70-year chronic exposure period, leading to a potential 

downward bias in both the MIR and population risk estimates.

7. Comment: Commenter 0171 noted that, in assessing the cancer risks related to source 

categories in the past, EPA used long-term concentrations affecting the most highly exposed 

census block for each facility. The commenter believes this analysis diluted the effect of sources’ 

emissions by estimating the impact at the centroid of the census block instead of at the property 

line or wherever the maximum exposed individual is. Since census blocks can be large 

geographically, depending on the population density, the maximum point of impact can be far 

from the centroid, including at or near the property line where people may live or work. In this 

assessment, however, when identifying the maximum individual risk receptor, EPA reviewed 

each individual facility and checked that the offsite concentration represented not just the closest 

census block centroid, but also the closest populated receptor.

Commenter 0161 supported EPA conducting a review of each individual facility and 

visually checking that offsite concentration represents the closest populated receptor for 

identifying maximum individual risk (MIR) receptors.

Response: We agree with the comments and have enhanced our receptor modeling to 

account for these problematic census blocks. For this source category we added additional 

receptors in an effort to improve our risk characterization, 

8. Comment: Background Exposure. Commenter 0218 asserted that the EPA failed to 

satisfy section 112(f)(2) by not following scientific recommendations and the best available 

science regarding the need to assess the full, cumulative impact of HAP exposure for affected 

local communities, and by failing to include past or background exposure as part of its health 

risk assessment. The commenter argued that the EPA failed to account for the impact of adding 

new air emissions to recent and past air emissions that the most-exposed people have already 

experienced from this source category for inhalation and multipathway risk assessments. The 

commenter asked the EPA to consider that pulp and paper facilities have emitted persistent, 

bioaccumulative HAPs for years in affected communities, and to account for the health risk that 

has already accrued due to higher historic emissions, emissions from multiple sources, and a 

build-up of contamination in the environment through deposition that then creates other routes of 
12

exposure. The commenter reminded the EPA that the SAB recommended that the EPA include 

an analysis of both background and incremental risk as part of a full cumulative impacts analysis.

Response: The EPA conducted an assessment of the cumulative cancer risks from 

emitted carcinogens and the cumulative noncancer hazard indices from all emitted noncarcinogens affecting the same target organ system for both the source category emissions and 

the facility-wide emissions. This assessment excluded background contributions from HAPs as 

well as persistent and bioaccumulative HAPs (PB-HAPs). While the incorporation of additional 

background concentrations from the environment in our risk assessments from the past or future

(including those from mobile sources and other industrial and area sources) could be technically

challenging, they are neither mandated nor barred from our analysis. In developing the decision 

framework in the Benzene NESHAP5currently used for making residual risk decisions, EPA 

rejected approaches that would have mandated consideration of background levels of pollution in 

assessing the acceptability of risk, concluding that “comparison of acceptable risk should not be 

associated with levels in polluted urban air” (54 FR 38044, 38061, September 14, 1989). 

Background levels of certain HAPs can be relatively high, perhaps even above a level that might 

be considered “safe.” Background levels (including natural background) are not barred from 

EPA‘s ample margin of safety (AMOS) analysis, but EPA may consider them, as appropriate and 

as available, along with other factors, such as cost and technical feasibility, in the second step of 

its section 112(f) analysis. In this analysis, background levels were not considered because it is 

technically infeasible since technical limitations in the data set for this source category make it

insufficient to create a reliable analysis.

9. Comment: Commenter 0162 expressed concern about EPA’s use of a version of its 

HEM3 model and corresponding receptor and meteorological data sets that are not in the public 

domain, which the commenter indicated prevented them from independently verifying and 

interpreting EPA’s risk findings. Specifically, the commenter said that, in applying HEM3, EPA 

applied a more robust set of hourly meteorological data than the data available on the HEM3 

website. In addition, the commenter said that EPA revised the population-based receptor files in 

HEM3 to exclude receptors that appeared to be on-site and to add receptors in nearby residential 

areas. According to the commenter, while EPA had, upon their request, shared detailed HEM3 

output, the unavailability of the updated program and data prevented a more in-depth and 

comprehensive review and examination of the effects of correcting model inputs in terms of 

modeled risks.

Commenter 0196 stated that EPA should place the HEM model and corresponding data 

sets in the docket for this rule to allow for public review and comment of these key materials.

The commenter noted that EPA computed the inhalation risk estimates for this sector using the 

Agency’s Human Exposure Model (HEM3-AERMOD). According to the commenter, for this 

assessment, EPA updated the public domain version of HEM3 so that the program implements

the current version of AERMOD. While these types of modeling enhancements are suitably 

incorporated into the RTR, the commenter stated that EPA’s use of a version of HEM3 and 

corresponding receptor and meteorological data sets that were not in the public domain 

 

5 National Emission Standards for Hazardous Air Pollutants: Benzene Emissions from Maleic Anhydride Plants, 

Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene Equipment Leaks, and Coke By-Product Recovery 

Plants (54 FR 38044, September 14, 1989) (Benzene NESHAP).
13

prevented them from independently verifying and interpreting EPA’s risk findings. The 

commenter argued that this created a “public notice” problem that easily could be corrected by 

placing the model and corresponding data sets in the docket and providing an opportunity for 

public comment on these materials.

Response: We are working with our contractor to look at the feasibility to provide the 

multi-facility HEM modeling software on our website. The single-facility HEM model will be 

updated to include census data for both 2000 and 2010 as well as the population receptors added 

for this source category. A complete inventory of meteorological stations used for this source 

category will also be available. The newest version of HEM available on the EPA website, along 

with the receptor adjustment information available in the risk assessment report and the input 

files available in the docket, can be used to produce results similar to the ones we generated in 

our output files (also available for comparison in the docket) for each facility.

4.2.1 Modeling of MACT Allowable Emissions

10. Comment: Commenter 0218 supported the EPA’s decision to consider “allowable”

emissions as well as “actual” emissions, so that EPA can understand the amount of health risk its

current standards allow to occur.

Response: We have discussed the use of both allowable and actual emissions in previous 

actions, including the final Coke Oven Batteries residual risk rule (70 FR 19998-19999, April 15, 

2005) and in the proposed and final HON residual risk rules (71 FR 34428, June 14, 2006, and 

71 FR 76603, December 21, 2006, respectively). In those previous actions, we noted that 

modeling the allowable levels of emissions (i.e., the highest emission levels that could be emitted 

while still complying with the NESHAP requirements) is inherently reasonable since they reflect 

the maximum level sources could emit and still comply with national emission standards. But we 

also explained that it is reasonable to consider actual emissions, where such data are available, in 

both steps of the risk analysis, in accordance with the Benzene NESHAP. We also note that our 

use of allowable emissions levels in the risk assessments in this rulemaking did not result in 

revising the previously established standards due to risk concerns.

11. Comment: Commenter 0171 recommended that EPA consider potential or allowable 

emissions, rather than actual emissions, as much as possible in evaluating residual risk. Since 

facility emissions could increase over time for a variety of reasons, and with them the associated 

impacts, the use of potential or allowable emissions is more appropriate. The commenter argued 

that an analysis based on actual emissions from a single point in time could underestimate the 

residual risk from a source category. Further, the commenter noted that the major source HAP 

thresholds are based on maximum potential-to-emit, as opposed to actual emissions, and air 

agencies issue permits based on potential emissions. According to the commenter, limiting the 

scope of a risk evaluation to actual emissions would be inconsistent with the applicability section 

of part 63 rules. The commenter was pleased to see that EPA used allowable emissions in parts 

of the rulemaking but was concerned about the fact that EPA continues to use actual emissions in 

other parts of its assessment. Commenter 0171 encouraged the Agency to use allowable 

emissions in the future, including in assessing acute health risks.
14

Response: We disagree with the comment suggesting the use of allowable emissions in 

the assessment of acute health effects. Our worst-case acute health screen for the pulp and paper 

source category already uses conservative assumptions for emission rates, meteorology, and 

exposure location, including (1) using peak 1-hour emissions that are on average two times the 

annual average 1-hour emission rates; (2) assuming all emission points experience peak 

emissions concurrently; (3) using worst-case meteorology (from 1 year of local meteorology); 

and (4) assuming that a person is located downwind at the point of maximum impact during this 

same 1-hour period. Thus, we believe performing an acute analysis based on allowable emissions 

would result in an overestimation of potential acute impacts that it is not useful to decision 

makers. 

12. Comment: According to commenters 0162 and 0196, EPA cannot lawfully use MACT 

allowable emissions in the proposed residual risk determinations because it has failed to provide 

any reasoned explanation for why risk assessments based on actual emissions estimates are 

inadequate. The commenters pointed out that CAA section 112(f)(1)(A) requires EPA to report 

to Congress on “methods of calculating the risk to public health remaining, or likely to remain, 

from sources subject to regulation under this section after the application of standards under 

subsection (d) of this section” (emphasis added). In addition, the commenters noted that CAA 

section 112(f)(1)(B) requires EPA also to report on “the actual health effects with respect to 

persons living in the vicinity of” affected sources” (emphasis added). The commenters asserted 

that these requirements clearly signal that Congress expected EPA to focus on actual risk and not 

hypothetical risk in implementing the requirements of section 112(f). According to the 

commenters, it is not reasonable in the first instance for EPA to construe section 112(f) as 

authorizing EPA risk assessments based on hypothetical “MACT allowable” emissions.

The commenters further noted that EPA’s risk assessment methodology already reflects 

numerous conservative assumptions. To illustrate, the commenters pointed out that health 

benchmarks (e.g., acute reference doses), typically incorporate two to three orders of magnitude 

of conservatism to account for uncertainties, such as the extrapolation of animal toxicity testing 

data to humans. In a similar example, the commenters also pointed out that the dispersion models 

used to predict off-site ambient HAP concentrations attributable to emissions from affected 

sources incorporate numerous conservative assumptions to simplify the analysis of highly

complex factors, such as meteorology, terrain, and atmospheric chemistry. In addition, the 

commenters noted that risk assessments assume exposure to the most exposed individual on a 

continuous basis for an entire lifetime.

Commenters 0162 and 0196 concluded that, in light of the conservatism that already is 

inherent in EPA’s risk assessment methodology, it makes no sense to apply yet another layer of 

conservatism to section 112(f) risk assessments–this time based on the hypothetical assumption 

that affected sources should be expected to emit more than the actual data indicate. The 

commenters also argued that EPA had provided no data or analyses indicating that its current 

methodology would result in a negative bias. According to the commenters, EPA has provided 

no data demonstrating that affected sources actually do emit at levels significantly higher than 

the actual data show for any significant period of time, or should reasonably be expected to do 
15

so.6To conclude, the commenters argued that EPA’s proposal to use hypothetical emissions 

levels in section 112(f) risk assessments was based on nothing more than the unsupported 

assertion that sources might emit at these higher levels. According to the commenters, the failure 

to provide a reasoned explanation or evidence as to why this approach is justified and the failure 

to provide any record evidence supporting the use of MACT allowable emissions renders the 

proposal insupportable under the law.

Response: We have discussed the use of both allowable and actual emissions in previous 

actions, including the final Coke Oven Batteries residual risk rule (70 FR 19998-19999, April 15, 

2005) and in the proposed and final HON residual risk rules (71 FR 34428, June 14, 2006, and 

71 FR 76603, December 21, 2006, respectively). In those previous actions, we noted that 

modeling the allowable levels of emissions (i.e., the highest emission levels that could be emitted 

while still complying with the NESHAP requirements) is inherently reasonable since they reflect 

the maximum level sources could emit and still comply with national emission standards. But we 

also explained that it is reasonable to consider actual emissions, where such data are available, in 

both steps of the risk analysis, in accordance with the Benzene NESHAP.

We also note that our use of allowable emissions levels in the risk assessments in this 

rulemaking did not result in a different outcome than the use of the actual emission levels.

4.2.2 Modeling of Facilitywide Emissions

13. Comment: Commenter 0218 stated that the EPA failed to recognize the significance of 

its facility-wide risk assessment, and to satisfy section 112(f)(2), the EPA must perform a 

cumulative impacts analysis that combines this source category’s individual impact with the 

impact from other sources. The commenter cited statements from the mineral wool production 

and wool fiberglass manufacturing NESHAP and EPA’s 2007 resource document on cumulative 

health risk assessment of multiple chemicals, exposures and effects (attached to the comment 

letter) indicating the EPA’s acknowledgement of the importance of cumulative impacts. The 

commenter supported the EPA’s recognition of the need to consider facility-wide risk in this 

rulemaking, but questioned the EPA’s conclusions that the pulp and paper source category did 

not drive the facility-wide cancer and chronic non-cancer risk. The commenter argued that the 

EPA should not focus on the 50 percent cut-off, because numbers below that may merit greater 

emission reductions from this source category to reduce the facility-wide risk overall.

Commenter 0218 recommended that the EPA perform a cumulative impacts analysis by 

combining current baseline emissions, exposures, and health impacts in addition to those of the 

specific source category EPA is reviewing. As part of this analysis, the commenter added, the

EPA should aggregate or add the emissions for the most-exposed communities coming from: (1) 

the source category (including all individual sources within it); (2) facility-wide risk from 

collocated sources outside of this category; and (3) all other sources of toxic air pollution in the 

area. The commenter suggested that the EPA aggregate the community’s exposure and assess the 

full health threats faced by the affected community, including from the sources under review. To 

 

6 According to the commenter, mills necessarily design and operate their emission control systems to operate at 

emission rates below the applicable standards, to provide a compliance margin that accommodates variability in 

process and control equipment.
16

perform this step, EPA must also draw on California EPA’s Office of Environmental Health 

Hazard Assessment OEHHA community assessment approach.

To the contrary, commenters 0162 and 0196 argued that, despite EPA’s assertion that it 

examines the risks from the entire facility in order to put the source category risks in context 

(where “facility” includes all HAP-emitting operations within a contiguous area and under 

common control (76 FR 81338)), EPA is without authority to consider facility-wide risks 

because the CAA requires residual risk determinations to be conducted on a category-bycategory basis. Commenter 0162 noted that section 112(f)(2)(A) unambiguously requires EPA, 

within 8 years after adopting a MACT standard for a given source category or subcategory, to 

“promulgate standards for such category or subcategory if promulgation of such standards is 

required in order to provide an ample margin of safety to protect public health.” According to the 

commenter, section 112(f)(2)(A) further dictates that, “Emissions standards promulgated under 

this subsection shall provide an ample margin of safety to protect public health.” The commenter 

asserted that it is not reasonable to construe these provisions as authorizing EPA to consider 

emissions from entire facilities in conducting risk assessments and potentially revising the 

underlying rule, for the simple reason that the Congress clearly envisioned that full 

implementation of the MACT program would take longer than 8 years. Commenters 0162 and 

0196 concluded that it would be impossible for EPA to fulfill its unambiguous obligation for 

section 112(f) standards to protect public health with an ample margin of safety in cases where 

facilities contain sources in a category where the 8-year deadline for conducting the section 

112(f) risk review precedes the adoption of MACT standards for other sources at the facilities.

Commenter 0162 further pointed out the provision in section 112(f)(2)(A), which states 

that:

[i]f standards promulgated pursuant to subsection (d) of this section and 

applicable to a category or subcategory of sources emitting a pollutant (or 

pollutants) classified as a known, probable or possible human carcinogen do not 

reduce lifetime excess cancer risks to the individual most exposed to emissions 

from a source in the category or subcategory to less than one in one million, the 

Administrator shall promulgate standards under this subsection for such source 

category. (emphasis added)

According to commenters 0162 and 0196, this provision unambiguously requires the 

section 112(f) risk assessment to be focused exclusively on “emissions from a source in the 

category or subcategory.” The commenters argued that, for this reason alone, EPA does not have 

authority to consider emissions from any sources other than those in the source category or 

subcategory under review at that time. As a result, the commenter concluded, the risk assessment 

EPA conducted for the proposed rule overstates the risks that EPA was supposed to be 

considering in the residual risk review for subpart S.

Response: Facility-wide risk estimates were three times higher than the risk from the 

pulp and paper subpart S source category. When facility-wide risk estimates are significant and 

significantly larger than the source category risk estimates, we determine the key emission 

sources associated with that difference and describe them along with our plans to address them 

via regulation in the preamble. We may also perform additional quality assurance (QA) on the 
17

facility-wide emissions in such cases. In the case of this rulemaking package, the results were not 

significant, and did not change any of the risk-based decisions, so additional follow-up was not 

needed or performed. 

An assessment of the cumulative cancer risks from emitted carcinogens and the 

cumulative noncancer hazard indices from all emitted non-carcinogens affecting the same target 

organ system (i.e., a target organ-specific hazard index [TOSHI] value) for the source category

emissions was conducted by EPA. This assessment excluded background contributions. The 

incorporation of additional background concentrations from the environment in our risk 

assessments from the past and future (including those from mobile sources and other industrial 

and area sources) are neither mandated nor barred from our analysis. In developing the decision 

framework in the Benzene NESHAP currently used for making residual risk decisions, EPA 

rejected approaches that would have mandated consideration of background levels of pollution in 

assessing the acceptability of risk, concluding that comparison of acceptable risk should not be 

associated with levels in polluted urban air‘‘ (54 FR 38044, 38061, September 14, 1989). 

Background levels of certain HAPs can be relatively high, perhaps even above a level that might 

be considered “safe.” Background levels (including natural background) are not barred from 

EPA‘s ample AMOS analysis, but EPA may consider them, as appropriate and as available, 

along with other factors, such as cost and technical feasibility, in the second step of its section 

112(f) analysis.

4.2.3 Modeling of Acute Exposure

14. Comment: Commenter 0161 supported EPA’s guidelines to assess acute exposures in a 

community to never exceed short-term occupational guidelines that are used to protect healthy

adult workers. However, commenter 0161.1 expressed concern for EPA’s use of acute exposure 

guideline levels (AEGLs) or emergency removal program guidelines (ERPGs) to address acute 

exposure. The commenter stated that the use of these values is for once-in-a-lifetime short-term 

exposure to airborne concentrations of acutely toxic chemicals. The AEGLs and ERPGs do not 

have safety and uncertainty factors associated with them. The commenter believes that the EPA’s 

use of the California reference exposure levels (RELs) to address the acute exposures in its 

residual risk assessments is a reliable and realistic approach to assess the potential for acute 

public health impacts for sensitive subpopulations.

Commenter 0171 also stated that the use of AEGLs or ERPGs in residual risk 

assessments is not appropriate and does not ensure that public health is adequately protected 

from the acute impacts of HAP exposure. These limits were developed for accidental release 

emergency planning and are not appropriate for assessing daily human exposure scenarios. In the 

December 2002 EPA document, "A Review of the Reference Dose and Reference Concentration 

Processes," EPA stated that the primary purpose of the AEGL program is to develop guidelines 

for once-in-a-lifetime, short-term exposures to airborne concentrations of acutely toxic 

chemicals. They are not meant to evaluate the acute impacts from routine emissions that occur 

over the life of a facility. Unlike the reference concentrations (RfCs) for chronic exposures, the 

AEGLs and ERPGs do not include adequate safety and uncertainty factors and cannot be relied 

upon to protect the public from the adverse effects of exposure to toxic air pollutants. The 

commenter expressed gratification to see that EPA has increased its reliance on the California 

RELs to address acute exposures in the residual risk assessments, and the commenter continued 
18

to urge EPA to use RELs for these assessments. The commenter also appreciated EPA’s 

recognition that the guidelines for acute exposures in a community should never exceed shortterm occupational guidelines used to protect healthy adult workers.

Response: When available, EPA uses AEGL and ERPG values in conjunction with REL

values to fully characterize potential acute health risks. However, it is often the case that HAPs

do not have all of these acute reference benchmark values. In these instances, EPA can only 

describe the potential acute health risk in relation to the acute health values that are available. 

Importantly however, when interpreting the results, we are careful to note the definition of the 

benchmark being used and the health implications associated with any specific benchmark being 

exceeded.

15. Comment: Commenter 0161.1 stated the average hourly emissions rate is defined as the 

total emissions for a year divided by the total number of operating hours in the year. The choice 

of a factor of 10 for acute screening is the default for the HEM3 model, and it is based on 

engineering judgment. However, for the pulp and paper source category, EPA has maximum 

hourly emissions estimates for each process group that indicate that a factor of two is more 

appropriate for this source category. The EPA determined that the worst-case maximum 

estimated 1-hour exposure to formaldehyde outside the facility fence line had a hazard quotient 

(HQ) of five or a predicted ambient concentration of 250 micrograms per cubic meter (ug/m3).

This concentration exceeds the short-term recommended exposure level (REL) for formaldehyde 

developed by National Institute for Occupational Safety and Health (NIOSH) of 0.12 ug/m3for 

any 15-minute period in a work day. The EPA undertook a refined analysis of the worst-case 

maximum 1-hour exposure estimate for formaldehyde, and the predicted impact remained the 

same, indicating that the maximum concentration likely came from one particular source. The 

HEM3 model becomes overly conservative when calculating the maximum receptor from 

multiple sources (see Appendix 7 of draft risk assessment report). 

Response: The formaldehyde NIOSH level is 0.12 milligram per cubic meter (mg/m3) vs.

the 12 mg/m3, resulting in a HQ NIOSH = 2. A review of the MIR facility for acute non-cancer 

impacts identified that 96 percent of the emissions of formaldehyde were emitted from a two 

sources (i.e., wastewater kraft emissions). The MIR off-site location for this facility was the St. 

Paul Waterway in Commencement Bay just North of Tacoma, WA. The HQ values where people 

reside for this facility would result in a HQ NIOSH < 1.

16. Comment: Commenter 0218 stated that, by ignoring risk from malfunctions, other 

violations, and higher emissions during startup periods, EPA’s proposal fails to consider the full 

cancer and chronic non-cancer health risk from this source category. The commenter observed 

that the CAA specifically requires EPA to base its risk analysis on the highest potential risk “to 

the individual most exposed to emissions from a source in the category or subcategory.” The 

commenter stated that it is necessary for the EPA to analyze risk based on what emissions may

indeed occur during a malfunction and other types of violations, even with the MACT standard 

in place. The commenter noted that these events increase HAP emissions and thereby pose 

increased health risks which EPA must consider.

The commenter also argued that although the “allowable” emissions limit represents the 

maximum level of emissions to which an individual may legally be exposed from a given facility
19

under the existing MACT, that analysis is incomplete because facilities may violate that standard 

and emit HAPs at a level beyond what is “allowable” under the rule. The commenter asserted 

that the EPA knows that there is additional risk from malfunctions and violations and it cannot 

ignore that risk. The commenter asked that the EPA should account for the heightened risk from 

exceedances of the MACT in its risk calculation, using data regarding the use of the malfunction 

exemption and enforcement actions in the past and other information it has regarding the history

or likelihood of malfunctions or other violations. The commenter pointed to the EPA’s use of a 

worst-case scenario used to calculate acute health risk, and suggested that the EPA should create 

a factor that would account for the potential for malfunctions and violations of the standard and 

then assess health risk accordingly for acute, cancer, and non-cancer risk when emissions spike 

above the allowable level under the existing standard. The commenter asked that the EPA 

consider the percent control efficiency for control devices used in the pulp and paper source 

category. When control devices fail, the commenter noted, emissions spike from the small 

percentage not controlled by the control device to the entire 100 percent from the controlled 

process.

The commenter stated that, although the EPA’s MIR is based on the assumption that 

exposure is constant for a lifetime, spikes in emissions over a person’s lifetime may

underestimate the amount of chronic risk based on pollutants that persist in the environment, 

including chromium and arsenic. The commenter asserted that the failure to account for greater 

risk due to malfunctions violates section 112(f)(2) and is arbitrary and capricious.

Response: Based on Response from Secondary Lead RTC p. 109. We disagree with the 

commenter that emissions that exceed standards and are violations, whether or not caused by 

malfunction events, should be considered as part of the risk analysis. The purpose of the risk 

review is to evaluate whether the emission limits should be made more stringent to reduce the

risk posed after compliance with the underlying MACT standard. To the extent that a source is 

violating the underlying MACT standard, no tightening of the emission standard under the 

residual risk rule will avoid or mitigate against such violations. In other words, a source that is 

violating the MACT emissions standard promulgated under section 112(d) would not be any

more likely to be able to avoid such violations and comply with a different presumably more 

stringent standard promulgated under section 112(f). Such events are violations and subject to 

enforcement by the EPA, the states, or citizens, and an action for injunctive relief is the most 

effective means to address violations, whether or not they are caused by malfunctions, if an 

emissions event poses a significant health or environmental risk.

Although we disagree that emissions that result in a violation should be considered as 

part of the risk review, we note that we believe malfunction events do not contribute significantly 

to cancer or chronic non-cancer risks for the source category in this rulemaking because 

malfunction events are inherently short-term and infrequent relative to annual operations and 

emissions. The commenter did not supply any data to the contrary.

Furthermore, the conservative estimates built into the acute risk assessment are sufficient 

to gauge worst-case potential acute health effects. The conservative estimates built in to the 

assessment include worst-case meteorology, emissions in excess of the maximum peak emission 

rate from all point sources simultaneously, and the summation of the maximum impact of each 
20

emission source, regardless of receptor location.7Thus, even if we were to consider emissions 

that are in violation of the standard, we do not believe that they would result in any different 

level of control.

17. Comment: Commenter 0218 stated that the existing standards allow uncontrolled 

emissions to occur 1 to 10 percent of the time, for various sources (§§63.443(e), 63.446(g)), but 

noted that the EPA’s risk assessment fails to consider the increased cancer, chronic non-cancer, 

and other types of health risk due to these periods of no-control. The commenter asserted that 

this violates section 112(f)(2) and is arbitrary and capricious. Further, the commenter asserted,

the EPA cannot justify refusing to assess this health risk based on its theory that it can ignore 

exceedances of the standard, because under the existing standard these periods of “excess 

emissions” are allowed.

Commenter 0218 stated that the EPA failed to calculate the maximum acute health risk 

based on a true “worst-case” scenario, because the EPA, by not anticipating higher risk from 

malfunctions, had not used a high enough emissions factor for usual operation. The commenter 

questioned the EPA’s multipliers to assess peak 1-hour emissions, arguing that higher ones 

would be more appropriate. The commenter observed that the existing standards include excess 

emissions allowances, which EPA should remove, and that allow uncontrolled emissions 1 to 10 

percent of the time. 

The commenter stated that the EPA has not demonstrated that the multipliers that it used 

are high enough for pulp and paper to assess the true acute risk to the most-exposed individual 

and community under EPA’s existing standards, recommending that the EPA use a multiplier of 

at least 10, noting that a factor of 10 is clearly too low to calculate acute health risk if a source, in 

a worst-case scenario, could emit as much as 12 to 50 times, or more, beyond its usual emissions.

Response: We acknowledge the commenter’s concern that the excess emissions 

allowances in subpart S currently could permit uncontrolled venting of emissions from low 

volume high concentration (LVHC) and high volume low concentration (HVLC) collection 

systems and bypassing steam stripper systems for up to 1 percent, 4 percent, and 10 percent of 

time, respectively, for reasons described in the preamble to the April 15, 1998 final rule at 63 FR 

18529-18530. These allowances are not considered violations of the standards, but were built 

into the standards as representative of the MACT level of control. In light of the Sierra Club

decision (Sierra Club v. EPA, 551 F. 3d 1019 (D.C. Cir. 2008)), we requested comment on these 

excess emissions allowances in the December 27, 2011 proposal (76 FR 81346), and our 

response to these comments is provided in section 8 of this document.

We disagree with the commenter that the multipliers we used for assessing acute risk 

were too low. The risk assessment and acute multipliers for the pulp and paper subpart S source 

category were based on a detailed analysis of emissions inventory data collected in 2011 through 

a section 114 ICR. The ICR requested routine annual emissions (tpy) and the routine emissions 

maximum hourly rate (pounds per hour [lb/hr]) for the year. The routine emissions reported 

reflect actual emissions for the calendar year (i.e., controlled emissions and emissions during any 

 

7

See memorandum from T. Holloway, K. Hanks, C. Gooden, and M. Hakos, RTI, to J. Bradfield and B. Schrock, 

EPA, titled Inputs to the Pulp and Paper Industry October 2011 Residual Risk Modeling, Table 6B, November 11, 

2011, in the docket for the subpart S rulemaking.
21

times when the excess emissions allowances were employed during the year). The annual (tpy) 

and peak (lb/hr) ICR data were compared to develop the peak-to-mean multipliers for the various 

emissions process groups in the subpart S source category. The resulting multipliers ranged from 

1 to 3.1 and are presented in Table 3 below.

8

The results of our peak-to-mean analysis were 

similar to those from separate analyses provided by the pulp and paper industry for two types of 

emissions units (papermaking and wastewater). Even though we performed a detailed analysis of 

multipliers for the different emission process groups in order to understand the effect of any 

process-specific factors (such as the excess emissions allowances) that could potentially lead to 

different multipliers, we ultimately modeled with a single multiplier of 2 for each facility when 

estimating acute risks, consistent with our practice of conservatively estimating acute risks based 

on the maximum peak emission rate from all point sources simultaneously (with the exception 

being mechanical pulping, where the indicated multiplier of 3.1 shown in Table 3 below, was 

used). For the facilities that had an HQ > 1, the specific acute multiplier for each emission 

process group was used to accurately characterize the risk. The adjusted HQ values for each 

emission point was than summed and plotted to identify the polar or census block receptor with 

the maximum off-site acute non-cancer risk.

In addition to being considered as part of the acute risk analysis, the excess emissions 

allowances were also taken into account in our analyses of chronic cancer and non-cancer risks 

based on both actual and “allowable” emissions. Like the acute analysis, the chronic risk 

analyses were based on the actual emissions reported in the ICR responses, which included

controlled emissions and emissions during any times when the excess emissions allowances were 

employed during the year. The risk analysis for MACT allowable emissions was based on the 

actual emissions reported in the ICR responses (which included emissions during times covered 

under the excess emissions allowances) scaled up with an “allowable” factor to approximate the 

difference between actual emissions performance and the compliance margin MACT allows. The 

allowable factors were developed for the various emission process groups considering the most 

commonly used compliance options under subpart S.

Table 3. Acute Multipliers by Emission Process Group for Risk Modeling for Subpart S 

(MACT Code 1626-1)9

Emission process group

Acute 

multiplier Emission process group

Acute 

multiplier

Bleaching: ClO2 Generator 1.4 Kraft Stock Washing 1.2

Bleaching: Kraft 1.4 Manuf Misc 1.4

Bleaching: Mechanical 1.4 Mechanical Pulping 3.1

Bleaching: Sec Fiber 1.4 NSSC Misc 1

Bleaching: Sulfite 1.4 NSSC Pulping 1

Causticizing: Green Liquor 1.5 Paper Misc 1.6

Causticizing: Lime Mud 1.5 Paper Stock Prep 1.6

Causticizing: Misc 1.5 Papermaking 1.6

Causticizing: Slaker 1.5 Semichem Misc 1

Causticizing: White Liquor 1.5 Semichem Pulping 1

Condensate Stripper 1.2 Soda Misc 1.2

 

8

Id.

9

Id.
22

Emission process group

Acute 

multiplier Emission process group

Acute 

multiplier

Kraft Misc 1.2 Storage Tanks - Alcohol 1.6

Kraft Pulp Storage 1.2 Storage Tanks - Methanol 1.6

Kraft Pulping: BL Tanks 

HVLC

1.2 Sulfite Pulping 1.6

Kraft Pulping: Decker 1.2 Sulfite Pulping (Ca) 1.6

Kraft Pulping: Digester LVHC 1.2 Sulfite Pulping (NH3) 1.6

Kraft Pulping: Evaporator 

LVHC

1.2 Tall Oil 1.2

Kraft Pulping: HVLC 1.2 Wastewater (General) 2

Kraft Pulping: Incinerator 1.2 Wastewater (Kraft) 2

Kraft Pulping: Knotter 1.2 Wastewater (Mechanical) 2

Kraft Pulping: LVHC 1.2 Wastewater (NSSC) 2

Kraft Pulping: O2 Delig HVLC 1.2 Wastewater (Semichem) 2

Kraft Pulping: Turpentine 

LVHC

1.2 Wastewater (Sulfite) 2

Kraft Pulping: Washing 1.2

To further alleviate concerns about acute risk, we note that events covered under the 

excess emissions allowances for LVHC and HVLC typically last less than one hour (some only a 

few seconds at a time). For the kraft condensate standards, the 10 percent allowance covers times 

when less than the required amount of HAP in condensates are collected (e.g., due to process 

variability when HAP concentrations are lower than normal), or when a steam stripper could be 

bypassed. Condensates bypassing the stripper are typically routed to a mill’s wastewater 

treatment system, where biological treatment occurs, and even wastewater treatment systems that 

are not designed and monitored for compliance with the condensate standards would provide 

some (e.g., 80 to 90 percent) treatment of the kraft condensates (minimizing acute effects).

Additionally, the excess emissions allowances could be triggered by times when monitoring 

parameters are outside of the pre-approved operating limits. While monitoring parameters serve 

as indicators of emissions, a slight deviation from pre-approved parameter limits accounted for 

against the backstop time limit of the excess emissions allowances does not necessarily reflect an 

acute emissions episode harmful to the population surrounding the mill. Finally, we note that the 

final rule requires additional repeat emission testing for kraft pulping processes and steam 

strippers and removes the SSM exemption–changes which should further reduce the potential for 

acute emissions episodes.

4.2.4 Multipathway Screening

18. Comment: Commenter 0161.1 recommended that EPA define the appropriate departure 

point for exceeding the mass screening value and requiring a multipathway risk analysis. The 

EPA used its Total Risk Integrated Methodology, Environmental Fate, Transport, and Ecological 

Exposure Module (TRIM.FaTE) to screen PB-HAPs for significant non-inhalation exposures. At 

all 38 facilities in the pulp and paper industry source category, the emissions rate for each PBHAP was below the screening thresholds, with the exception of one facility for which the 

emission rate of polycyclic organic matter (POM) exceeded the screening threshold by a factor 

of two. The screening level is designed to represent a potential for creating a cancer risk in 
23

excess of 1-in-a-million or a non-cancer hazard index (HI) of 1. The commenter believes this to 

be a proper use of screening values. The mass emission rate screening process will be successful 

if conservative input data are used within the TRIM.FaTE model and risk management decisions 

are incorporated into the decision making process. In this case, a risk management decision was 

made to allow two times the mass emission rate, equaling approximately a 2-in-a-million cancer 

risk. This approach contrasts favorably to EPA’s risk assessment for the primary aluminum 

NESHAP source category, in which the emissions from POM exceeded the mass emission 

screening rate by 7,000 times for one facility and the EPA decided not to pursue a refined 

multipathway risk assessment. To avoid similar discrepancies, EPA should create a defined 

hierarchy to require this type of risk assessment under the RTR program.

Response: As described above, since proposal, EPA has refined the emission screening 

thresholds in the multipathway screen based on TRIM.FaTE runs to screen risks from PB-HAP 

emissions. This revised Tier 1 screen uses improved toxicity rating/scaling methods for POMs 

and dioxin congeners as well as improved fate, transport, and uptake behavior through the 

aquatic food chain. Based on the above changes, the facility-level emissions of POMs from the 

pulp and paper source category are now below the screening threshold by a factor of 9.

For more information on the changes made to the PB-HAP Tier I screening thresholds 

refer to Appendix 4 of the Residual Risk Assessment for the Pulp & Paper Source Category in

the docket for the subpart S rulemaking.10

19. Comment: Commenter 0218 stated that the EPA failed to add add multipathway risk to 

the inhalation risk to come up with a total cancer risk and a cumulative burden metric that EPA 

and the public can analyze, making EPA’s overall risk assessment incomplete. The commenter 

recommended that the EPA use the multipathway assessment appropriately by adding the risk 

found there to the inhalation risks found, and then proceeding with the required section 112(f)(2) 

analysis to determine whether or not that total level of risk is acceptable, to show the full 

cumulative burden of health risk for the most-exposed person, and what standards are needed to 

reach an acceptable level and also to provide an ample margin of safety.

Response: It would be inappropriate for EPA to add a screening threshold exceedance as 

an estimate for multipathway risks with the modeled inhalation risks. The screening threshold is 

not intended to be used to produce quantitative estimates of actual or potential risk. Rather, it 

provides a basis for determining if residual human health risks are of potential concern. The 

screening thresholds are based upon a worst-case scenario, which likely overestimates exposures 

for the site; actual exposures will depend upon geography, meteorology, land-use, and other 

characteristics, as well as release parameters for those pollutants that are PB-HAPs. 

20. Comment: Commenter 0218 disagreed with the EPA’s conclusion that there is “no 

potential for . . . human health multipathway effects” from POM emissions. The commenter 

stated that the EPA’s POM multipathway analysis is incomplete because EPA failed to conduct a 

full multipathway risk assessment, which includes consideration of a child’s multipathway

 

10 See U.S. EPA’s Residual Risk Assessment for the Pulp & Paper Source Category, Appendix 4, “Overview of 

Tiered Approach to Assessing Multipathway Exposures for RTR,” in the docket for the subpart S rulemaking
24

exposure, in urban and rural residential scenarios. The commenter recommended EPA conduct 

such a full multipathway risk assessment.

The commenter further stated that the failure of EPA to assess an exposed child scenario 

as part of the cumulative risk assessment ignores the exposures that may pose the most 

significant risk from this source category. The commenter highlighted the risk to children from 

contaminated soils, noting that past risk assessments have relied on outdated estimates of 

incidental soil ingestion exposures and stating that the EPA must update these values. The 

commenter cited two EPA exposure factors handbooks and a journal article as resources to use 

for assessing risks.

Response: The EPA disagrees with the commenter’s statement that this risk assessment 

failed to consider children’s exposure and early-life susceptibility. The EPA agrees that 

biological differences across life stages may lead to differences in the susceptibility to HAP, as 

can differences among population groups, due to pre-existing disease states or other factors.

Accordingly, the methods we use in risk assessments have taken this into account. For the doseresponse component of HAP assessments for RTR, the EPA uses exposure reference 

concentrations and unit risk estimates that are expressly derived with the objective of protecting 

sensitive populations and life stages, including children.11 For example, a review of the chronic 

reference value process concluded that the Agency’s RfC derivation process adequately 

considered potential susceptibility of different subgroups with specific consideration of children, 

such that the resultant RfC values pertain to the full human population, including “sensitive 

subgroups,” which is inclusive of childhood. Cancer risk assessments are performed in 

accordance with EPA’s Supplemental Guidance.12 This Guidance recommends the application of 

age-dependent adjustment factors for assessing cancer risk from carcinogenic pollutants 

concluded to act via a mutagenic mode of action and for which information on early-life 

susceptibility is lacking. The basis for this methodology is provided in the 2005 Supplemental 

Guidance. With regard to other carcinogenic pollutants for which early-life susceptibility data 

are lacking, it is the Agency’s long-standing science policy position that use of the linear lowdose extrapolation approach (without further adjustment) provides adequate public health 

conservatism in the absence of chemical-specific data indicating differential early-life 

susceptibility or when the mode of action is not mutagenicity.

13

The EPA developed the scenario in the multipathway screen in order to estimate the 

upper end of the range of individual, long-term, non-inhalation exposures for situations likely to 

be encountered in the United States. The approach is described in the “Overview of Tiered 

Approach to Assessing Multipathway Exposures for RTR,” available as Appendix 4 to the risk 

assessment document for subpart S.14 This approach has been reviewed and approved by the 

 

11 See U.S. EPA (2002), A Review of the Reference Dose and Reference Concentration Processes. EPA/630/P02/002F. Risk Assessment Forum, Washington DC. Available online at: 

http://www.epa.gov/raf/publications/pdfs/rfd-final.pdf.

12 See U.S. EPA (2005), Supplemental Guidance for Assessing Susceptibility from Early-Life Exposure to 

Carcinogens. EPA/630/R-03/003F. Washington, DC. Available online at:

http://www.epa.gov/cancerguidelines/guidelines-carcinogen-supplement.htm.

13 Id.

14 See U.S. EPA’s Residual Risk Assessment for the Pulp & Paper Source Category, Appendix 4, “Overview of 

Tiered Approach to Assessing Multipathway Exposures for RTR,” in the docket for the subpart S rulemaking.
25

SAB to characterize a worst-case scenario in a rural environment; we believe the parameters 

used for this simulation are reasonable for purposes of conducting a multipathway assessment for 

both adults and children, especially considering the close proximity of the emission source(s) to 

farmland and/or fishable lakes, which are major considerations in conducting a multipathway

risk assessment.

The EPA purposely designed the multipathway scenario to produce conservative (i.e., 

health protective) results. To this end, EPA applied the following critical exposure/activity

assumptions: fresh water fish ingestion rates (99th percentile); food ingestion rates (90th 

percentile rates)15; adults/children greater than 6 years of age (90th percentile)16; and soil 

ingestion children less than 6 years of age (95th percentile).

17 These ingestion rates are based 

upon EPA’s 2011 Exposure Factors Handbook and have been revised to reflect high-end 

consumption rates for the general public and high-end rates for at-risk populations, such as 

children ingesting contaminated soil.

21. Comment: Commenter 0218 stated that the EPA did not perform a full multipathway

risk assessment for lead, and this is unlawful, irrational, and unjustified. The commenter 

observed that EPA compared the ambient air concentrations caused by the facilities’ emissions 

with the 2008 national ambient air quality standard (NAAQS) for lead (0.15 μg/m3) to assess 

whether there would be exceedances of the NAAQS, but what is “adequate” under section 109 is 

not necessarily “acceptable” under section 112. The EPA must ensure that it sets standards that 

provide an “ample margin of safety to protect public health.” The commenter concluded that the

EPA should have performed a full multipathway risk assessment for lead that looked at the full 

exposure from ingestion and dermal pathways, such as through soil and breast-milk exposure.

Response: The lead NAAQS was a public health policy judgment considering the 

available health evidence and risk analyses, as well as the uncertainties associated with the health 

evidence and risk analyses. We disagree with the commenter that the lead NAAQS cannot be 

used in a quantitative manner. The review of the lead NAAQS clearly resulted in a quantitative 

standard: 3-month maximum lead concentration not to exceed a level of 0.15 μg/m3. 

The NAAQS for lead was set to protect, with an adequate margin of safety, the health of 

children and other at-risk populations against an array of adverse health effects, most notably

neurological effects, particularly neurobehavioral and neurocognitive effects, in children. 73 FR 

67007. Because of the multipathway, multimedia impacts of lead, the risk assessment supporting 

the NAAQS for lead considered direct inhalation exposures and indirect air-related multipathway

exposures from industrial sources like primary and secondary lead smelting operations. It also 

considered background lead exposures from other sources, like contaminated drinking water and 

exposure to lead-based paints. During the NAAQS review process, these risk estimates were 

judged to be roughly consistent with, and generally supportive of, the evidence-based framework 

applied in the NAAQS determination (73 FR 67004). Taken together, the EPA believes that the 

 

15 See U.S EPA, Exposure Factors Handbook: 2011 Edition; EPA/600R-090/052F. Available online at: 

http://www.epa.gov/ncea/efh/pdfs/efh-complete.pdf

16 Id.

17 Stanek, E., EJ Calabrese, R Barnes, & P Pekow. (1997) “Soil ingestion in adults – results of a second pilot study.” 

Toxicol. Environ Safety, 36(249-257).
26

lead NAAQS is a reasonable benchmark to evaluate the potential for multipathway health effects 

from lead.

Also, as noted in the risk assessment document18, there is no reference dose (RfD) or 

other comparable chronic health benchmark value for lead compounds. That is, in 1988, the 

EPA’s Integrated Risk Information System (IRIS) program reviewed the health effects data 

regarding lead and its inorganic compounds and determined that it would be inappropriate to 

develop an RfD for these compounds, saying:

A great deal of information on the health effects of lead has been obtained through 

decades of medical observation and scientific research. This information has been 

assessed in the development of air and water quality criteria by the agency's Office of 

Health and Environmental Assessment (OHEA) in support of regulatory decision-making 

by the Office of Air Quality Planning and Standards (OAQPS) and by the Office of 

Drinking Water (ODW). By comparison to most other environmental toxicants, the 

degree of uncertainty about the health effects of lead is quite low. It appears that some of 

these effects, particularly changes in the levels of certain blood enzymes and in aspects of 

children's neurobehavioral development, may occur at blood lead levels so low as to be 

essentially without a threshold. The agency's RfD Work Group discussed inorganic lead 

(and lead compounds) at two meetings (07/08/1985 and 07/22/1985) and considered it 

inappropriate to develop an RfD for inorganic lead.19

The lead NAAQS applies in all areas of the United States regardless of the age of the 

individuals living in a particular area. Thus, we find it appropriate to evaluate potential 

multipathway risks, in a quantitative manner, using the NAAQS for lead.

22. Comment: Commenter 0218 expressed concern that the EPA restricted its multipathway

risk screening assessment for this source category to only those contaminants that were identified 

in the 2003 Risk Assessment Guidance as being both persistent and bioaccumulative in the 

environment (i.e., PB-HAPs). The commenter observed that this list of 14 PB-HAPs is 

incomplete, as it ignores other HAPs that present multipathway risks. The commenter stated that 

the EPA’s restrictive choice is not supported by the 2003 Guidance and underestimates risks 

from HAPs emitted by this source category. The commenter specifically named all metals 

emitted by this source category, including chromium, arsenic, nickel, and manganese, as 

pollutants that require a full multipathway risk assessment. The commenter cited the California 

OEHHA recommendation of multipathway assessment for these metals. The commenter 

concluded that the EPA may not assume that the ingestion risks are zero for these pollutants, and

doing so when science shows otherwise is arbitrary and capricious. The commenter stated that 

not assessing multipathway risk from exposure to these HAPs via incidental ingestion, both 

individually and cumulatively, results in an underestimation of the risks of HAP emissions from 

this source category. The commenter also recommended that naphthalene, as a polycyclic 

aromatic hydrocarbon (PAH), must be considered in the POM category.

 

18 See U.S EPA, Residual Risk Assessment for the Pulp & Paper Source Category, in the docket for the subpart S 

rulemaking

19 See the EPA’s IRIS assessment for Lead and compounds (inorganic) (CASRN 7439-92-1). Available online at: 

http://www.epa.gov/iris/subst/0277.htm.
27

Response: In the Air Toxics Assessment Library20, we developed the current PB-HAP 

list, considering all of the available information on persistence and bioaccumulation. This list 

was peer-reviewed by the SAB, and it is reasonable to use it in the RTR program. Based on the 

limited available information on the persistence and bioaccumulation of the metals mentioned in 

the comment above, we do not believe that the potential for multipathway risk rises to the level 

of the PB-HAPs currently on the list.

23. Comment: Commenter 0218 objected to the EPA’s use of reported emissions rather than 

allowable emissions in its multipathway assessment, stating that the EPA has not assessed the 

full potential for non-inhalation health risk due to persistent and bioaccumulative emissions. The 

commenter observed that intermittent or short spikes of PB-HAPs can represent a significant 

health risk because the contaminants stay in the environment and small amounts can accumulate 

into larger amounts over time. The commenter stated that failing to account for the full 

multipathway risk that EPA’s existing standard allows, or for risk due to violations from that 

standard, violates the section 112(f)(2) requirement to ensure protection for the individuals “most 

exposed” to the source category.

Response: As noted in the risk assessment document, allowable emissions were about 

1.5 times greater than actual emissions for this source category. Because there is a linear 

relationship between emissions and the results of this worst case screen, considering allowable 

emissions, the current screening level for POMs is approximately 6 times greater than the 

estimated allowable emissions. These allowable emissions do not exceed our POM screening 

thresholds and are estimated to be below an excess cancer risk of 1 in a million.21

4.2.5 Dose-response Benchmarks

24. Comment: Commenter 0218 stated that the EPA must assess health risk from all 

pollutants, even where it has no current reference value, and must use an uncertainty factor to 

make up for the lack of a reference value. The commenter observed that the EPA’s risk 

assessment acknowledges the emission of other HAPs for which it has no reference values, but 

that the EPA failed to assess risk at all for these pollutants. The commenter also stated that the 

EPA did not carry out a qualitative assessment of these HAPs, in effect assuming that risk from 

the HAPs is zero, which is not justified, and which underestimates health risk. The commenter 

asserted that at minimum, EPA must use an uncertainty factor to make up for the lack of 

reference values, and EPA may not treat risk as zero for a HAP simply because it has no 

reference value for the health risk from that HAP. Section 112 requires EPA to address all 

emitted HAPs in its regulation. The commenter concluded that EPA must address this 

uncertainty by selecting a health-protective value based on the information it does have, so that it 

may consider the potential risk and find an appropriate way to assess that risk in this rulemaking. 

In the absence of an available reference dose, EPA must, at minimum, add an uncertainty factor 

to account for the additional risk that a HAP likely causes, until such time as EPA does have a 

reference value to use. Using a protective uncertainty factor would allow EPA to satisfy its legal 

 

20 See http://www.epa.gov/ttn/fera/risk_atra_main.html.

21 For more information on the changes made to the PB-HAP screening thresholds, refer to U.S. EPA’s Residual 

Risk Assessment for the Pulp & Paper Source Category, Appendix 4, “Overview of Tiered Approach to Assessing 

Multipathway Exposures for RTR,” in the docket for the subpart S rulemaking.
28

duty under section 112(f)(2) to prevent unacceptable health risk and ensure an “ample margin of 

safety to protect public health.”

The commenter pointed to section 112(f)(2) of the CAA as creating a critical duty and 

opportunity for EPA to conduct a comprehensive and protective analysis of residual risk to 

public health and the environment. However, over the 20 years after the CAA was amended, the 

IRIS review process has been bogged down for many pollutants, and sufficient studies for some 

HAPs have not been conducted to allow calculation of reference doses, reference concentrations, 

or potency values. The commenter asserted that the EPA should prevent the delay in this process 

from undermining its residual risk analysis for this and other source categories.

The commenter recommended that for formaldehyde, methanol, and all other pollutants 

currently under IRIS reassessment, EPA must use the best available scientific information from 

the IRIS review during the current rulemaking. The commenter stated that if EPA determines 

that it must wait until these reassessments are complete to use the newly available scientific 

information, then EPA must take a more protective approach due to the outdated health risk 

reference information that it is using. For formaldehyde, the commenter supported the EPA using 

the 1991 IRIS value, as well as information from the new IRIS review, rather than the industrycreated value from the Chemical Industry Institute of Toxicology (CIIT), which is less 

protective.

The commenter suggested that to account for the delay and lack of reference values for 

some pollutants, and the fact that it is still updating the toxicity information for other pollutants, 

EPA must set a regulatory deadline no later than 8 years from the finalization of these rules, to 

review the current residual risk analysis and again perform a residual risk rulemaking once 

additional data on reference values become available.

Response: Based on Response from Secondary Lead RTC p. 63 This issue was addressed 

by the SAB Panel in their May 10, 2010 response to the EPA Administrator.

22 In that response, 

the SAB Panel recommended that, for HAPs that do not have dose-response values from the 

EPA’s hierarchy list, the EPA should consider and use, as appropriate, additional sources for 

such values that have undergone adequate and rigorous scientific peer review. They further 

recommended that the inclusion of additional sources of dose-response values into the EPA’s 

hierarchy should be adequately documented in a transparent manner in any residual risk 

assessment case study. We agree with this approach and have considered other sources of doseresponse data when conducting our risk determinations under RTR. However, in some instances,

no sources of information in addition to the EPA’s hierarchy are available.

The EPA agrees that we should ultimately develop toxicity values for all HAPs using all 

credible and relevant toxicity information. The need to update assessments with newly available 

data, as well as the need to complete toxicological assessments for all HAPs lacking doseresponse assessments, further increases the importance of Agency activities to streamline and 

fully use the EPA’s already overloaded IRIS program. To that end, the EPA has always 

prioritized for future IRIS assessments those HAP without dose-response values but with the 

 

22 See SAB's Response to EPA's RTR Risk Assessment Methodologies (EPA-SAB-10-007), available online at: 

http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-

unsigned.pdf
29

greatest potential for public exposure. As a result of this prioritization, while not all HAPs may 

have scientifically accepted dose-response values that can be used in residual risk assessments, it 

is clear that the vast majority of HAPs which might carry the potential to significantly impact the 

results of residual risk assessments do, in fact, have credible dose-response values. Thus, while 

we are not yet at the point where all HAPs have dose-response values, we are generally capable 

of deriving reasonable risk estimates for those HAP which dominate the risks from any one 

source category. In the course of each residual risk assessment, should we encounter HAP 

without dose-response values which carry the potential to create significant risks, we shall 

clearly point those out as uncertainties and target them for future IRIS assessments. Moreover, as 

additional dose-response values become available, the EPA will incorporate these dose-response

values into future risk assessments. 

The dose-response values that were used in this risk assessment are based on the current 

peer reviewed IRIS values. At the time this analysis was performed, these values were deemed to 

represent the best science. Revised IRIS were not available at the time the analysis was 

performed. We cannot pick and choose newly available values that have not gone through the 

IRIS (or other similarly accepted) review process. We cannot delay rules for new IRIS values 

that may be developed in the future; however, we can re-examine rules as new health 

information becomes available. Also, the commenter falsely assumes that all new IRIS doseresponse values will be more stringent than the existing values. The new IRIS doses-response 

values could be less or more stringent, or equal to the existing values, depending on what the 

scientific data support.

The EPA disagrees that with the commenter that we did not state which HAPs currently 

have no reference value. Table 3.1-1 in the risk assessment document23 lists all the HAP emitted 

by the source category, as well as whether there is an available cancer, chronic noncancer, and/or 

acute dose-response value. Over 99.8 percent of the HAP emitted in this category has one or 

more of these reference values.

Regarding the commenter’s suggestion that EPA must conduct another residual risk 

analysis no later than 8 years from the finalization of the subpart S amendments, CAA section 

112(f)(2)(A) requires EPA to assess the remaining risk no later than 8 years after promulgation 

of the standards for each source category; additional assessments are neither stipulated or 

prohibited.

25. Comment: Arsenic. Commenter 0174 noted that the current unit risk estimate (URE) for 

chronic cancer risk for arsenic in the IRIS database is 0.0043 μg/m3. The commenter stated that 

this risk factor was derived in the 1984 EPA Health Assessment Document (HAD) and is the 

basis of risk estimates in the HEM3 risk assessment model. During its reassessment of the North 

Carolina acceptable ambient level (AAL) for arsenic during 2011, the North Carolina Science 

Advisory Board for Toxic Air Pollutants (NCSAB) included updated epidemiological data24 with 

 

23 See Table 3.1-1 of U.S. EPA’s Risk Assessment for the Pulp & Paper Source Category, in the docket for the 

subpart S rulemaking.

24 Lubin et al., Respiratory cancer in a cohort of copper smelter workers: results from more than 50 years of followup Am J Epidemiol 151:554–565 (2000); Lubin et al., Respiratory Cancer and Inhaled Inorganic Arsenic in Copper 

Smelters Workers: A Linear Relationship with Cumulative Exposure that Increases with Concentration. 

Environmental Health Perspectives 116(12) (2008); Järup et al., Cumulative arsenic exposure and lung cancer in 
30

additional person-years and NC-specific lung cancer mortality rates that alter the 1984 EPA risk 

estimate as a function of cumulative arsenic exposure. Additionally, there is better scientific 

understanding in 2012 compared to 1984 of the forms of arsenic involved in environmental 

exposures and differences between risk based on industrial health and environmental exposure 

studies. The NCSAB concluded that, based on current science, the 1984 URE for arsenic used by 

EPA is out–of-date and overestimates cancer risk by almost one order of magnitude. The 

NCSAB also concluded that the thresholds for non-cancer risks associated arsenic are higher 

than cancer risk threshold and that arsenic standards based on cancer risk are protective of all 

health risk.

Response: The EPA has a hierarchy of appropriate health benchmark values, and, in 

general, this hierarchy places greater weight on the EPA-derived health benchmarks than those 

from other agencies, including benchmarks developed by the NCSAB 25,26 We have a 

prioritization process aimed at incorporating into our assessments the best available science with 

respect to dose-response information. This information is obtained from various sources and 

prioritized according to (1) conceptual consistency with EPA risk assessment guidelines and (2) 

level of peer review received. Where we are lacking dose-response information with higher 

priority (e.g., IRIS), we use other information sources, such as the California Environmental 

Protection Agency (CalEPA). Notably, this hierarchy favoring EPA benchmarks (when they

exist) over all others has been endorsed by the SAB:

27

“The Panel found EPA‟s approach to selecting dose-response chronic toxicity values to 

be generally sound... The Panel supports the use of the Integrated Risk Information 

System (IRIS) as the preferred database for chronic dose-response data. The Panel also 

strongly recommends that EPA develop toxicity values for all HAP insofar as the data 

permit, and that it updates IRIS in a timelier manner.” “The preferred database for 

chronic dose-response data is and should be the IRIS database. (p. 17).” 

The URE value that was used in this risk assessment for arsenic is based on the current 

peer-reviewed IRIS assessment (published in 1998, not in 1984 as the commenter stated). At the 

time this analysis was performed, this value was deemed to represent the best available science. 

A revised IRIS value for arsenic was not available at the time the analysis was performed, and 

we cannot pick and choose newly available values that have not gone through the IRIS (or other 

similarly accepted) review process.

26. Comment: Acrolein. Commenter 0162 stated that the health effects caused by exposure 

to acrolein are overestimated in EPA’s IRIS database. The commenter noted that, in 2007, the 

Hamner Institute completed a study of acrolein’s health effects, which included 90-day

 

smelter workers: A dose-response study. Am. J. Ind. Med. 15: 31-41 (1989); Viren & Silvers, Unit risk estimates for 

airborne arsenic exposure: an updated view based on recent data from two copper smelter cohorts." Regul Toxicol 

Pharmacol 20(2): 125-138 (1994).

25 See Health Effects Information Used In Cancer and Noncancer Risk Characterization For the 1999 NationalScale Assessment. Available online at: http://www.epa.gov/ttn/atw/nata1999/99pdfs/healtheffectsinfo.pdf.

26 See http://daq.state.nc.us/toxics/risk/sab/ra/.

27 See SAB's Response to EPA's RTR Risk Assessment Methodologies (EPA-SAB-10-007), available online at: 

http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-

unsigned.pdf.
31

animal/rat studies, as well as work on a computational fluid dynamic (CFD) model on uptake of 

acrolein to understand biological dose. According to the commenter, this research was then 

published in a peer-reviewed journal.28 The commenter pointed out that on October 17, 2008, 

they sent a letter advising EPA of the new studies and in December 2010 asked EPA to update its 

acrolein IRIS assessment and amend the risk value for acrolein using the Hamner studies. Before 

EPA estimates any risk from acrolein emissions, the commenter urged that the IRIS assessment 

on acrolein be revised to reflect the best available science.

Commenter 0162 acknowledged that the SAB Panel, in February 2010, supported the use 

of IRIS as the “preferred” database, but the commenter noted that the Panel also advised EPA to 

consider alternatives where the IRIS values are based on limited data. The commenter 

specifically cited the Panel’s statement that it “found EPA’s approach to selecting dose-response

chronic toxicity values to be generally sound, but recommends the Agency more closely 

scrutinize values that emerge as drivers of risk assessment results.”29 The commenter included 

Table 4 below comparing the acrolein RfCs used by government organizations for risk analysis, 

which, according to the commenter, shows that EPA’s current value for acrolein is not based on 

the best available scientific data and is more than 15 times more stringent than the RfCs 

established more recently by CalEPA and Ontario Ministry of the Environment (MOE).

Table 4. Comparison of Acrolein RfC Used by Various Government Organizations

(Submitted by Commenter 0162)

Government 

Agency Previous RfC (μg/m3) Recent RfC (μg/m3) Year of Recent RfC

EPA 0.02 0.02 2003

Hamner Institute -- 0.6 2008

CalEPA 0.06 0.35 2008

Ontario MOE 0.08 0.4 2009

Commenter 0162 noted that EPA’s current RfC is based on a study by Feron (1978) that 

examined few animals, did not involve exposure concentrations low enough to develop a no 

observed adverse effect level (NOAEL)--(just a lowest observed adverse effect level (LOAEL)--

and did not study nasal uptake/activity. According to the commenter, EPA has acknowledged the 

study was of poor quality and that large uncertainty factors were used (1000x). The commenter 

cited the following statement from EPA in a technical document regarding the use of health 

effects information in evaluating school air toxic monitoring results:

The comparison level shown for acrolein is the EPA RfC which is set below a level 

associated with health effects. The RfC is set as a factor of 1000 below an exposure 

concentration associated with sensitive nasal effects in laboratory animals. Since the EPA 

RfC was derived, the California EPA (CalEPA) has derived a chronic REL30 based on 

 

28 Dorman, et al., Respiratory Tract Responses in Male Rats Following Subchronic Acrolein Inhalation, Inhalation 

Toxicology 20:205-216 (2008). Schroeter et al., Application of Physiological Computational Fluid Dynamics 

Models to Predict Interspecies Nasal Dosimetry of Inhaled Acrolein, Inhalation Toxicology 20:227-243 (2008). 

Struve, et al., Nasal Uptake of Inhaled Acrolein in Rats, Inhalation Toxicology 20:217-225 (2008).

29 See 5/7/10 letter from SAB Panel to EPA.

30 REL refers to a Reference Exposure Level. “CalEPA defines the REL as a concentration level at (or

below) which no health effects are anticipated, a concept that is substantially similar to EPA's noncancer
32

more recently available information on acrolein and its effects. The CalEPA REL, which 

is 0.35 μg/m3, is somewhat more than a factor of 100 below the level associated with 

effects in the more recently available study.

31

According to the commenter, the recommended value, based on the Hamner Institute 

study, is 30 times less stringent than what EPA is using (0.6 μg/m3(270 parts per trillion [ppt]) 

vs. 0.02 μg/m3(9 ppt)). The commenter noted that CalEPA (0.35 μg/m3) and Ontario, Canada 

(0.4 μg/m3) have set their RfCs at much less stringent levels. The commenter also noted that, in 

the technical document for interpretation of health effects surrounding schools, EPA referenced 

the values used by CalEPA and Ontario as more appropriate.

The commenter concluded that the alternative RfCs presented in the Hamner study are 

more scientifically valid than the EPA IRIS value and asserted that, when both the Hamner study

RfC and industry emissions data for acrolein are applied, the analysis would not support a 

conclusion that there are any significant residual risks associated with acrolein emissions from 

the pulp and paper source category.

Commenters 0162 and 0196 agreed with the decision to remove acrolein emissions from 

the subpart S modeling files “due to the uncertainty in the emissions estimates” (76 FR 81334).32

Commenter 0162 noted that acrolein is a very reactive gas and hard to measure at the parts per 

billion level of emissions. The commenter stated that the primary generators of acrolein 

emissions are fires and mobile sources, but that EPA has not regulated acrolein from mobile 

sources to date. The commenter said that the forest products industry is a very small contributor 

to ambient levels/loadings of acrolein because paper mill acrolein emissions would only be a 

fraction of the 1 percent emitted from boilers and process heaters, according to data from the 

2005 National-Scale Air Toxics Assessment (NATA).

Response: We acknowledge the commenters’ support for the conclusion regarding the 

uncertainty with acrolein emissions. Due to the removal of acrolein emissions from the subject 

source category, the applicability of the dose-response value used is not relevant for this 

rulemaking. Acrolein emissions were removed from the subpart S modeling file due to 

 

dose- Response assessment perspective.” http://www.epa.gov/ttn/atw/toxsource/chronicsources.html

31 Schools Air Toxic Monitoring Activity (2009) Uses of Health Effects Information in Evaluating Sample

Results, 09/10/2009, EPA, http://www.epa.gov/schoolair/pdfs/UsesOfHealthEffectsInfoinEvalSampleResults.pdf

32 Commenter 0162 noted that EPA elaborated on the causes of this uncertainty in its memorandum included as 

Appendix H to the RTI memorandum entitled, “Inputs to the Pulp and Paper Industry October 2011 Residual Risk 

Modeling,” located in the docket at EPA-HQ-OAR-2007-0544-0122. In the memo appendix, EPA explained that “in 

the case of acrolein from Subpart S non-combustion sources, this [EPA emission factor development] protocol 

results in emission factors based primarily on assumed 1⁄2-MDL values from a majority of test runs where acrolein 

was not detected which introduced a large number of unknowns into the dataset, thereby multiplying the 

uncertainties [in the source of acrolein emissions from non-combustion sources] outlined above to an unknown 

degree. The uncertainty in the initial data set is further magnified when the emission factors are applied across the 

industry, yielding a resultant acrolein emission inventory predicated primarily on assumed values and not actual 

emissions measurements. This magnified uncertainty is compounded with the additional uncertainty of acrolein 

emissions from different paper machine operating parameters and different wood species used in pulping, resulting 

in further exacerbation of the uncertainty.” Inputs Memo p. H-2.
33

uncertainty in the emissions estimates.33 The EPA is working with the industry to help improve 

the test methods for acrolein from non-combustion sources. Acrolein emissions were modeled 

for combustion sources in the facilitywide modeling performed for the subpart S RTR and will 

be included in future residual risk modeling efforts (e.g., for subpart MM). Emissions estimates 

will be updated prior to future residual risk modeling efforts based on additional information 

available at that time and the refinements to facilitywide emissions inventories received in 

response to EPA’s December 2011 request for comments on the data set. (76 FR 81346-81351)

27. Comment: Formaldehyde. Three commenters (0162, 0196, and 0208) objected to EPA’s 

use of the 1991 IRIS dose-response value in evaluating formaldehyde risk. Commenter 0208 

urged EPA to revise the proposed rule to accurately convey the best available science and a 

weight-of-evidence approach in compliance with the Information Quality Act (IQA) Guidelines 

and Executive Order (EO) 13563. In particular, the commenter asserted that EPA should reject 

the 1991 IRIS dose-response value and incorporate the 1999 CIIT cancer dose-response value for 

formaldehyde.34

Commenter 0208 stated that the proposed rule is subject to EPA and Office of 

Management and Budget (OMB) IQA Guidelines. Congress enacted the IQA, Pub. L. No. 106-

554, 114 Stat. 2763A-153 to 2763A-154, to “ensur[e,] and maximiz[e,] the quality, objectivity, 

utility and integrity of information ... disseminated by Federal agencies” such as the EPA. In 

2002, OMB issued its guidelines, and EPA issued its agency-specific guidelines (EPA IQA 

Guidelines) later that year.35 The information that serves as the basis for EPA’s proposed rule 

must meet OMB’s guidelines as well as the Agency’s own guidelines and must adhere to a 

rigorous standard of quality. The proposed rule is based on “influential” scientific risk 

assessment information as set forth in EPA IQA Guidelines36 because it contains “information 

disseminated in support of top Agency actions (i.e., rules...)” and is a “[m]ajor work product[]” 

that “will have ... a clear and substantial impact (i.e., potential change or effect) on important 

public policies or private sector decisions.”

37 The substance of the information must be 

“accurate, reliable, and unbiased.” EPA must use the best available science and supporting 

studies, as well as “a weight-of-evidence approach that considers all relevant information and its 

quality.”38

 

33 For more information, see memorandum from T. Holloway, K. Hanks, C. Gooden, and M. Hakos, RTI, to J. 

Bradfield and B. Schrock, EPA, titled Inputs to the Pulp and Paper Industry October 2011 Residual Risk Modeling, 

November 11, 2011, in the docket for the subpart S rulemaking.

34 Chemical Industry Institute of Toxicology (CIIT). 1999. Formaldehyde: Hazard characterization and doseresponse assessment for carcinogenicity by the route of inhalation (revised ed.).

35 OMB, Guidelines for Ensuring and Maximizing the Quality, Objectivity, Utility, and Integrity of Information 

Disseminated by Federal Agencies, 67 FR 8452 (Feb. 22, 2002) (OMB IQA Guidelines); see EPA, Guidelines for 

Ensuring and Maximizing the Quality, Objectivity, Utility, and Integrity of Information Disseminated by the 

Environmental Protection Agency, available at http://www.epa.gov/quality/ 

informationguidelines/documents/EPA_InfoQualityGuidelines.pdf.

36 Pub. L. No. 106-554. The Information Quality Act was developed as a supplement to the Paperwork Reduction 

Act, 44 U.S.C. §3501 et seq., which requires OMB, among other things, to “develop and oversee the implementation 

of policies, principles, standards, and guidelines to ... apply to Federal agency dissemination of public information.”

37 EPA IQA Guidelines at 19-20 (internal citations omitted); OMB IQA Guidelines at 8455.

38 EPA IQA Guidelines at 21.
34

Despite the numerous safeguards designed by OMB and EPA to ensure data quality, 

commenter 0208 argued that EPA has failed to rely on the best available science in developing 

the proposed rule. The EPA failed to comport with the IQA Guidelines in crafting the proposed 

rule. In particular, The EPA incorporated the 1991 IRIS dose-response model – an overly 

conservative and outdated model – for determining the level of risk presented by formaldehyde 

exposure and ignored, without any rationale, nearly 25 years of research. The commenter stated 

that the use of the IRIS model is all the more egregious considering the availability of the CIIT 

biologically-based dose-response (BBDR) model, which better reflects the available science.

Commenter 0208 further stated that, contrary to IQA guidelines, EPA inappropriately 

applied the outdated IRIS dose-response values in determining formaldehyde inhalation exposure 

risk in support of the proposed rule. In 2004, EPA determined that “the [formaldehyde] doseresponse value in IRIS is based on a 1987 study, and no longer represents the best available 

science in the peer reviewed literature.” 69 FR 18327, 18333 (Apr. 7, 2004). In this same 

determination, EPA went on to state the CIIT dose-response value was the most appropriate 

substitute. This determination led to the incorporation of the CIIT dose-response value for 

formaldehyde exposure in risk assessments supporting regulatory action. The commenter then 

highlighted EPA’s decision to use the IRIS value instead of CIIT dose-response in the proposed 

rule, following the recommendations of the NAS review (76 FR 81335). 

Commenter 0208 stated the NAS panel was highly critical of EPA’s 2010 Draft IRIS 

Toxicological Review of Formaldehyde Inhalation Assessment,39 and specifically supported the 

use of the CIIT BBDR model. (See NAS Report at 34-44.) In fact, the panel concluded that “the 

BBDR model for formaldehyde is one of the best-developed BBDR models to date” and 

specifically recommended that “EPA use the BBDR model for formaldehyde in its cancer 

assessment, compare the results with those described in the draft assessment, and discuss the 

strengths and weaknesses of each approach.” (See NAS Report at 5.)

Commenter 0208 noted that in 2010, EPA rejected the BBDR model because it asserted 

that the variability of the model is “not supportive of interpreting the CIIT model results as 

providing a conservative (health-protective) estimate of human risk.” (See 75 FR 80220, 80228 

(Dec. 21, 2010) (citing Crump et al., 2008).)

40 However, the sensitivity of the model had been 

questioned based on inappropriate manipulation. As explained by Conolly et al. (2009), while it 

is important to ensure that the BBDR model is “health protective” in its estimation of cancer risk 

by performing a sensitivity analysis, such an analysis is only valuable if it is constrained by

respect for the biological realism of the model-predicted behavior. The NAS panel agreed (see 

NAS Report at 5, see also id. at 42).

Commenter 0208 stated the 1991 IRIS value does not constitute the best available science 

and therefore should not be used in determining formaldehyde inhalation exposure risk in 

support of the Proposed Rule. The BBDR model, which incorporates over 20 years of research to 

help characterize the roles of regenerative cellular proliferation (RCP) and DNA-protein cross-

 

39 National Research Council of the National Academies, Review of the Environmental Protection Agency’s Draft 

IRIS Assessment of Formaldehyde (2011) (NAS Report).

40 Crump, K.S.; Chen, C.; Fox, J.F.; Van Landingham, C.; Subramaniam, R. 2008. Sensitivity Analysis of 

Biologically Motivated Model for Formaldehyde-Induced Respiratory Cancer in Humans. Ann. Occup. Hyg. 52:481-

495.
35

link (DPX) formation in formaldehyde carcinogenicity (see CIIT, 1999; NAS Report at 35), is a 

superior model for determining the cancer risk associated with formaldehyde exposure. The NAS 

panel concluded that “...The scope of the research makes this one of the best-developed BBDR 

models to date for any chemical, even with acknowledged uncertainties.” (See NAS Report at 

42.)

Furthermore, starting with biological data and a bottom-up linear extrapolation model 

using EPA’s assumptions, Swenberg et al. (2010) report, at S136-S137: 

Our estimates of HL [Hodgkin lymphoma] and LEU [leukemia] risk diverge even more 

dramatically from the corresponding U.S. EPA estimates.... The marked disparities 

between the adduct-based and epidemiology-based cancer risk estimates for distant sites 

suggest strongly that the excess risks of HL and NPC [nasopharyngeal cancer] that have 

been reported in association with occupational formaldehyde exposures cannot be due to 

formaldehyde.... Comparison of our risk estimates with corresponding estimates from the 

U.S. EPA draft document shows the latter to be markedly higher. This discrepancy

between results obtained with molecular dosimetry and those that rely on highly 

uncertain retrospective exposure reconstructions calls into serious question the credibility

of attributing increased human mortality from these cancers, particularly at distant sites, 

to occupational formaldehyde exposures.41

Commenter 0208 recommended that the NAS report should be used in determining what 

constitutes the best available science. The commenter stated that the deference given to the 1991 

IRIS Assessment is directly at odds with EPA’s mandate to “consider all credible and relevant 

information” in a rulemaking proceeding. The commenter noted that EPA has repeatedly 

emphasized that the Agency is required to consider other information, in addition to the IRIS 

database, when evaluating health effects in a regulatory context.42 In guidance on the use of IRIS 

for purposes of developing values under the early reduction program of the CAA, EPA noted: 43

It is also important to remember that IRIS is not a comprehensive toxicological database. 

There may be more recent information available than is contained in IRIS. Moreover, the 

act of including a value in IRIS is not subject to notice and comment rulemaking, and 

may not necessarily have been subjected to external peer review.... Accordingly, IRIS 

values are not entitled to conclusive weight and shall not be made legally binding in the 

context of any other rulemaking action. In addition, EPA or any State agency that uses 

IRIS should not rely exclusively on IRIS values but should consider all credible and 

relevant information that is submitted in any particular rulemaking. If an outside party

questions IRIS values during the course of an EPA proceeding..., EPA will consider all 

credible and relevant information before it in that proceeding.

 

41 Swenberg, J.A.; Lu, K.; Moeller, B.; Gao, L.; Upton, P.; Nakamura, J.; Starr, T. 2010. Endogenous versus 

Exogenous DNA Adducts: Their Role in Carcinogenesis, Epidemiology, and Risk Assessment. Toxicol. Sci. 

120(S1):S130-S145.

42 See Community Nutrition Instit. v. Young, 818 F.2d 943, 946 (D.C. Cir. 1987), McLoud Steel Prods. Corp. v. EPA, 

838 F.2d 1317 (D.C. Cir. 1988); see also EPA, Residual Risk Report to Congress, EPA-453/R-99-001 (Mar. 1999), 

at 61 (“As the IRIS assessments for some HAPs are less current than others, the Agency will evaluate the 

appropriateness of some assessments in light of more recent credible and relevant information.”).

43 U.S. EPA, Guidance on Use of Integrated Risk Information System (IRIS) Values, Office of Air Quality Planning 

and Standards (1994).
36

Commenter 0208 recognized the importance of considering all recent and relevant 

information instead of simply using IRIS assessment values as default values in Agency actions, 

which is echoed in an EPA Office of Solid Waste and Emergency Response (OSWER) 

directive.44 The need for careful examination of this information is also quite evident in the case 

of the formaldehyde dose-response value where the IRIS dose-response value is based on a study

that is over 20 years old. This fact was emphasized in the 2004 proposed rule for the NESHAP 

for stationary combustion turbines, 40 CFR part 63, where, in its discussion of the formaldehyde 

dose-response value, EPA stated that “the dose-response value in IRIS is based on a 1987 study, 

and no longer represents the best available science in the peer reviewed literature. Since that time 

significant new data and analysis has become available.” (See 69 FR 18333.) The commenter 

stated that the NAS panel’s unequivocal support of the CIIT BBDR model should be considered

when determining the best available science.

Commenter 0208 stated EPA’s proposed rule should be based on the best available 

science at the time of the rulemaking. The EPA’s reversion to the 1991 IRIS assessment value 

for use in the proposed rule not only violates its own guidance on the use of IRIS for purposes of 

developing toxicological values, but also fails to meet the rigorous data quality standards for 

“influential information” outlined in the IQA Guidelines. To determine what constitutes the “best 

available science,” the EPA is required to conduct a comprehensive review of the available 

science, and make a determination based on the weight-of-evidence. The EPA overly simplified 

this process by determining that the only two viable dose-response values were the CIIT value 

and the 1991 IRIS value. The EPA defaulted to the 1991 IRIS value without conducting a 

comprehensive review of the considerable body of research that has been conducted in the past 

20 years that may suggest an alternative value that is supported by the best available science. 

Commenter 0208 noted that the U.S. Court of Appeals for the D.C. Circuit, in Chlorine 

Chemistry Council v. EPA, 206 F.3d 1286 (D.C. Cir. 2000), further underscored the importance 

of rulemaking “on the basis of the best available science at the time of the rulemaking.” (See id. 

at 1291 (emphasis in original).) In holding that the best available science is the science available 

at the time of rulemaking, the D.C. Circuit Court unanimously rejected EPA’s contention that it 

would defer the application of the best available science until after input from the SAB on the 

carcinogenic mode of action of chloroform. “The word ‘available’ would be senseless if 

construed to mean ‘expected to be available at some future date.’” (See id.) Similarly, the 

research and data considered in the NAS Report of the Draft IRIS Assessment must be 

incorporated into this rulemaking; the EPA cannot legally defer application of the best available 

science.

Commenter 0162 attached comments from commenter 0208 (Formaldehyde Panel for the 

American Chemistry Council) to their public comments and cited commenter 0208’s statement 

that “the EPA has failed to support key conclusions . . . with the best available science”45 in 

evaluating the potential impacts from formaldehyde emissions. Commenter 0162 also cited

commenter 0208’s statements regarding EPA’s “egregious” use of the 1991 IRIS dose-response 

model instead of the CIIT BBDR model, which commenter 0162 said better reflects the available 

 

44 U.S. EPA, Use of IRIS Values in Superfund Risk Assessment, OSWER Directive No. 9285.7-16 (1993).

45 Comments from the Formaldehyde Panel for the American Chemistry Council in Response to EPA’s Proposed 

NESHAP from Pulp and Paper Industry (Docket No. EPA-HQ-OAR-2007-0544-0208.); 2/27/12
37

science46 and is supported in the April 2011 NAS Report of its review of formaldehyde risk.47

Commenter 0162 concluded that EPA is relying on an inferior model to support its impact

analysis of formaldehyde emissions from pulp and paper mills. According to commenter 0162, 

EPA inappropriately applied the outdated IRIS dose-response values in determining 

formaldehyde inhalation exposure risk in support of the proposed rule, contrary to IQA 

Guidelines. Commenter 0162 argued that the 1991 IRIS model does not constitute the best 

available science and, therefore, should not be used in determining formaldehyde inhalation 

exposure risk in support of the proposed rule. The commenter stated that CIIT’s BBDR model is 

a superior model for determining the cancer risk associated with formaldehyde exposure and 

argued that EPA overstated the variability associated with CIIT’s model and based its view on 

inappropriate manipulations of the model’s underlying assumptions. The commenter asserted 

that the deference given to the 1991 IRIS Assessment was directly at odds with EPA’s mandate 

to “consider all credible and relevant information” in a rulemaking proceeding and pointed out 

that EPA’s proposed rule should be based on the best available science at the time of the 

rulemaking.”48

Commenter 0196 attached comments from the Formaldehyde Panel that were provided in 

response to EPA’s proposed NESHAP for wood furniture manufacturing operations (Docket No. 

EPA-HQ-OAR-2010-0786)49, which were identical to the comments presented above, and 

concluded that EPA has repeated the same fundamental mistakes in the pulp and paper proposal. 

Commenter 0196 stated that EPA should follow NAS’s recommendation to use the “best 

available science” by applying the CIIT dose-response value rather than the outdated IRIS value.

Response: In 2004, the EPA determined that the CIIT cancer dose-response value for 

formaldehyde (5.5 E-9 μg/m3) was based on better science than the IRIS cancer dose-response 

value (1.3 E-5 μg/m3), and we switched from using the IRIS value to the CIIT value in risk 

assessments supporting regulatory actions. Subsequent research published by EPA suggested that 

the CIIT model was not appropriate, and in 2010 EPA returned to using the 1991 IRIS value.

The EPA has been working on revising the formaldehyde IRIS assessment, and the NAS 

completed its review of the EPA’s draft assessment in April of 2011.50 The EPA will follow the 

NAS Report recommendations and will present results obtained by implementing the BBDR 

model for formaldehyde. The EPA will compare these estimates with those currently presented 

in the External Review draft of the assessment and will discuss their strengths and weaknesses.

As recommended by the NAS committee, appropriate sensitivity and uncertainty analyses will be 

an integral component of implementing the BBDR model. In the interim, we will present 

findings using the 1991 IRIS value as a primary estimate, and EPA may also consider other 

information as the science evolves. We should note that adequately judging all of the data is the 

 

46 Id.

47 National Research Council of the National Academies, Review of the Environmental Protection Agency’s Draft 

IRIS Assessment of Formaldehyde (2011) (NAS Report), available at http://www.nap.edu/catalog.php?record 

id=13142.

48 Comments from the Formaldehyde Panel of the American Chemistry Council in Response to EPA’s Proposed 

NESHAP from Pulp and Paper Industry, Attachment 2.

49 Comments from the Formaldehyde Panel for the American Chemistry Council in response to EPA’s Proposed 

NESHAP for Wood Furniture Manufacturing Operations (Docket No. EPA-HQ-OAR-2010-0786).

50 National Research Council of the National Academies, Review of the Environmental Protection Agency’s Draft 

IRIS Assessment of Formaldehyde (2011) (NAS Report), available at http://www.nap.edu/catalog.php?record 

id=13142.
38

goal of this process, and mere substitution of another model with its own set of critical 

uncertainties should not be adopted without a full vetting, which is the process currently under 

way in the process of revising the IRIS value for formaldehyde.

Contrary to what commenter 0208 states, the NAS did not make any recommendations on 

which values should be used in regulatory decisions, but did recommend that EPA consider all 

credible and relevant information in developing its hazard assessment in the IRIS process. 

Inclusion of all credible and relevant information is best done within the revised IRIS process, 

which is informed by the NAS report. To circumvent that process for any specific context is 

likely to result in a less robust estimate of potential risk.

28. Comment: Lead. Commenter 0218 stated that there is no reference concentration for, or 

any safe level of exposure to, lead. The EPA assessed risk for lead by reference to the 2008 

NAAQS for lead, which the commenter did not believe was protective enough. The commenter, 

stated the EPA may not assume that what is “adequate” under section 109 is the same as what is 

“acceptable,” and EPA must independently determine under section 112 what is needed to 

provide an “ample margin of safety to protect health.” The commenter noted differences between 

section 109 and section 112 assessments: 

 The NAAQS was created to protect the average exposed member of the population from 

an IQ point loss above 2 points, not to protect the “most exposed” and most vulnerable 

member of that population who may experience greater harm at each level of exposure;

 The lead NAAQS was also designed to address only a single pollutant (elemental lead), 

while section 112(f)(2) requires EPA to assess and address health risk from lead 

compounds and from the combined effect of a source category’s HAP emissions on the 

most exposed person;

 There is significant new information since the scientific review closed on the NAAQS, 

suggesting that a stronger standard is needed (the commenter cited five documents from 

OEHHA, New York City (NYC) Department of Public Hygiene, Centers for Disease 

Control and Prevention (CDC), and CalEPA as references, and attached four of the 

documents); and

 Lead can interact with other pollutants, such as arsenic, to cause greater harm than lead 

exposure alone.

The commenter stated that section 112(f)(2) requires EPA to create an “ample margin of 

safety to protect public health,” while the NAAQS must only satisfy the test to provide an 

“adequate margin of safety.” The commenter asserted that rather than relying only on the 

NAAQS to assess health risk from lead, EPA should use all of the best available, most current 

information, including California’s lead health benchmark – which recognizes that action is 

needed to protect children from a blood-lead level increase of 1.0 micrograms per deciliter 

(μg/dL) – as part of its analysis of health risk for lead.

Response: We recognize, as the commenter noted, that there is no RfC for lead.

Nonetheless, it should also be noted that lead compounds are a minor HAP in this source 
39

category. Emission inventories indicate lead compounds are 0.0001 percent of HAP emissions.51

Lead emissions are generally below testing detection levels at category emission sources.

Reported inventory estimates, when present, are generally derived from extrapolations based on 

the small quantity of naturally-occurring lead found in the wood raw material. We believe it is 

appropriate here to use the lead NAAQS as a basis for determining risk under an ample margin 

of safety analysis. In this circumstance, the small quantity of lead emissions in the category 

results in exposure levels well below the NAAQS. As a result of our ample margin of safety

analysis, EPA found the risk from lead and other HAP emissions in this category to be 

acceptable.

So, in order to assess multipathway risks associated with emissions of lead, the EPA 

compared lead emissions from this category to the NAAQS for lead. As noted in the primary and 

secondary lead RTR rules (76 FR 70834 and 77 FR 556), we believe that this is a reasonable 

approach, given that the NAAQS is a health-based standard set to protect the public health, 

including the health of sensitive sub-populations with an adequate margin of safety. Moreover, 

the NAAQS for lead specifically is targeted to provide requisite protection with an adequate 

margin of safety to prevent neurologic effects to children with low blood lead levels living near a 

lead source and exposed at the level of the NAAQS. Also, the risk assessment supporting the 

NAAQS considered direct inhalation exposures and indirect air-related multipathway exposures 

from industrial sources like pulp and papermaking operations. While we conclude that the 

NAAQS presents an acceptable level of risk from lead in ambient air, as part of our “ample 

margin of safety” analysis, we examined whether there were additional cost-effective controls 

available to further protect public health. For the reasons explained in the proposal and other 

supporting documents available in the docket, we have determined that there are no additional 

cost-effective, technically feasible controls that would provide further risk reductions.

With respect to the benchmarks from OEHHA, NYC Department of Public Hygiene, 

CDC, and CalEPA for protecting children, the EPA has a hierarchy of appropriate health 

benchmark values. In general, this hierarchy places greater weight on EPA-derived health 

benchmarks than those from other agencies.52 For further information on EPA responses 

regarding lead, please refer to the Response to Comment Document for the Secondary Lead 

Smelting Source Category; this document will be included in the docket for the pulp and paper 

rule.

4.3 Uncertainties in Risk Assessment

29. Comment: Commenter 0161.1 believes that the methodology used to determine the 

inhalation exposure risk from HAPs is not a conservative assessment. The commenter questioned

using the centroid, instead of the maximum exposed individual or property line, to estimate MIR. 

The commenter argued that the HEM3 model should include building downwash parameters.

Because these were not included, the commenter contended that ambient concentrations were 

underestimated. The commenter stated that all RTR assessments should include 2010 census data 

 

51 See memorandum from T. Holloway, K. Hanks, C. Gooden, and M. Hakos, RTI, to J. Bradfield and B. Schrock, 

EPA, titled Inputs to the Pulp and Paper Industry October 2011 Residual Risk Modeling, Table 6B, November 11, 

2011, in the docket for the subpart S rulemaking.

52 See Health Effects Information Used In Cancer and Noncancer Risk Characterization For the 1999 NationalScale Assessment. Available online at:http://www.epa.gov/ttn/atw/nata1999/99pdfs/healtheffectsinfo.pdf.
40

instead of 2000 census data and provided an example to display the differences in the data for 

one location.

Response: The 2010 census data were not available at the time the risk analysis was 

performed for this source category. However, future risk analyses will incorporate 2010 census 

data.

30. Comment: Commenter 0218 supported EPA’s decision to collect and review actual 

emission test data from this source category for this rulemaking using its CAA section 114 

authority. The commenter believes that it is unclear whether EPA’s data set is actually

representative of emissions, because although it appears to include some test data, it also uses 

estimates. The EPA must provide the HAP emissions inventory with the emission totals of each 

HAP for each facility, and state whether this came from test data or estimates. Failing to include 

this makes it difficult for the public to review EPA’s data, which is the primary basis for EPA’s

proposed rule.

Response: The data set used to model emissions was representative of pulp and paper 

industry emissions. We described the NEI data set used for risk modeling in section III.A.1 of 

the preamble to the proposed rule (see 76 FR 81333-81334). The actual annual emissions data in 

the NEI database were based on data from actual emissions tests and estimates of actual 

emissions (based on emission factors) provided by subpart S sources surveyed in Part II of the 

2011 pulp and paper ICR. Two substantial QA efforts were conducted on the Part II data in order 

to create the modeling files needed for the residual risk assessment. Most emissions factors were 

based on actual tests or actual tests conducted at similar sources. Additionally, the largest HAP 

emission compound in the category, methanol, at approximately 86 percent of the HAP in the 

category, is required to be quantified in each compliance test referenced in the standard. 

Consequently, the greatest proportion of HAP emissions at each facility are based on emission 

factors derived from actual source-specific tests.

31. Comment: Commenter 0218 claimed that the EPA underestimated the total risk that 

maximum exposed people face due to emissions from the pulp and paper source category; the 

increased risk caused by a person’s exposure to multiple types of HAP; or the baseline level of 

exposure.

The commenter argued that uncertainty is not a rational explanation for failing to address 

this important element of health risk. Where public health is concerned, the commenter asserted, 

uncertainties require more conservative assessment and more protective action, rather than 

inaction; the EPA must, at minimum, use an uncertainty factor to account for the greater health 

risk, and the EPA must also follow the SAB recommendations to perform a sensitivity analysis 

to identify the major uncertainties in both the human health and ecological risk assessments, 

explain the uncertainties, and take steps to reduce them.

Response: With respect to developing an upperbound uncertainity factor to account for 

background contribution or synergistic effects, we believe this would bias the uncertainity in the 
41

risk assessment even higher. Please refer to Section 4 of the risk assessment report53 for more 

detailed discussions regarding the uncertainities for this risk assessment.

4.4 Risk Assessment Results

32. Comment: Multiple commenters (0162, 0163, 0165, 0167, 0173, 0196, and 0212)

supported EPA’s conclusion in the preamble to the proposed rule that “the current standard, 

before the amendments proposed here are put in place, protects public health with an ample 

margin of safety” (76 FR 81344). Commenter 0165 agreed with the EPA’s conclusion that the 

in-force MACT has worked and there is no risk, Commenters 0163 and 0167 agreed with EPA’s 

conclusion that there is no need for revised or additional MACT to address residual risk under 

this NESHAP. Commenter 0196 asserted that no further emissions reductions are needed to 

ensure protection of public health with an ample margin of safety.

Commenters 0163 and 0167 noted that the EPA made its conclusion whether considering 

their estimate of MACT allowable (i.e., worst-case) emissions or their estimate of actual 

emissions. The two commenters (0163 and 0167) contended that the EPA’s low-risk conclusion 

is understated because the risks probably are even less than EPA described; commenter 0163 

noted that MACT allowable emissions are typically substantially greater than actual emissions 

for a complying facility. Commenter 0172 argued that the estimated acceptable risks are 

overstated due to the use of conservative health benchmarks, inappropriate modeling 

assumptions, and overestimates of emissions and stated that, as a result, EPA’s conclusion that 

no further controls are needed is well founded. 

Commenter 0162 noted that the modeled risk results were based on data supplied by 171 

mills during the ICR in 2011. Commenter 0162 stated that the data collected comprised a 

comprehensive data set, reflecting the most up-to-date information and estimated that the 

industry spent over $5 million to respond to the ICR, not including the cost for the original 

collection of the data that were included in the survey. According to commenter 0162, the results 

of the analysis conducted by EPA show that the NESHAP subpart S rule was successful (i.e., 

that MACT worked). The commenter said that this success was due to many factors, including 

the approximately $1.0 billion dollars54 spent by the industry to achieve the emission reductions 

realized by the rule.

Response: We acknowledge the commenters’ support for our risk assessment conclusion 

that the current subpart S NESHAP protects public health with an ample margin of safety.

33. Comment: Commenter 0174 noted that the meteorological data used in the HEM3 model 

is not representative of the Blue Ridge Paper Products Inc. site-specific meteorological data. The 

data input to the model was from a local regional airport. Due to the complex terrain in the 

region, the commenter asserted that their site-specific meteorological data should be used. The 

company provided site-specific data that is used by the North Carolina Division of Air Quality

and EPA Region IV for modeling. The commenter provided specific data in their comment 

 

53 See U.S. EPA’s Risk Assessment for the Pulp & Paper Source Category, in the docket for the subpart S

rulemaking.

54 NCASI estimate for implementation of subpart S and subpart MM. Majority of the capital cost was for subpart S.
42

attachment and stated that the updated data showed a 60 percent decrease in HEM3 modeled 

risk. 

Response: The meteorological data set that was used in the pre-proposal modeling for 

this facility was the only data available to EPA at the time the modeling was conducted. We 

appreciate the commenter providing the meteorological data for remodeling risk for their facility

post-proposal. However, as discussed in the paragraph below (and in section 4.1.2), the EPA has

decided not to remodel risk for the pulp and paper source category.

At proposal, the EPA found the risk at each of the facilities in the source category to be 

acceptable under an ample margin of safety, and the post-proposal NEI data revisions provided 

by the industry (including this facility) will most likely adjust the risk results for the source 

category downward (i.e., reduce risk), based on our review of the data revisions. Because of this, 

the EPA has elected not to remodel risk for purposes of promulgating of the subpart S residual 

risk review, but instead to rely on the conclusions from the risk modeling conducted for the 

proposed rule. However, the meteorological data and comments provided by the commenter will 

be made a part of the public record in the docket for the subpart S rulemaking, along with 

documentation supporting the EPA’s decision not to remodel risk.

55

34. Comment: According to commenter 0162, their consultant (hereafter referred to with 

commenter 0162 as “the commenter”) found the following errors in model input parameters 

among the mills with higher modeled risk.56 The commenter expected that these types of errors 

are common among all of the mills and thereby likely contribute to a general overestimation of 

modeled risk from this industrial sector.

The commenter found that, in EPA’s refined assessment of the acute risk of subpart S 

sources, 11 HAPs and 9 mills had modeled maximum acute HQs of 1.5 and greater. Among 

these mills, the commenter determined that more than one-third (4 of 9) have impacts that are 

dominated by modeled wastewater treatment area sources that are incorrectly located.

According to the commenter, EPA’s assessment of the potential health effects due to 

long-term inhalation exposure from subpart S sources showed 42 mills had a modeled maximum 

individual lifetime cancer risk of 2 in a million or greater. The commenter found that predicted 

hazard indices for all mills were less than 1 for subpart S sources. For the 42 mills, the 

commenter made the following observations:

 The commenter found that risks at more than 64 percent of these mills (27 of 42) are 

primarily associated with emissions from mill sources characterized as area sources, 

simplistically representing a large number of discrete emission sources. According to the 

commenter, in dispersion modeling, it is commonly found that a more detailed source 

characterization materially reduces modeled concentrations and associated modeled 

maximum off-site risk. The commenter indicated that this is largely because modeling as 

 

55 See memorandum from T. Holloway, RTI, to J. Bradfield, B. Schrock, K. Spence, and N. Swanson, EPA. 

Recommendations Concerning Residual Risk Remodeling for the Pulp and Paper Industry, May 8, 2012, in the 

docket for the subpart S rulemaking.

56 See Attachment 1, “Review of HEM Modeling Conducted by EPA for the Pulp and Paper Industry RTR,”

AECOM, February 2012.
43

area sources inherently assumes that all emissions in the area are released at a single 

height and no credit is given for plume rise associated with individual point sources.

 The commenter found that about 17 percent of the mills (7 of 42) were characterized as 

single point emission sources or with consolidated releases emitted from only a few 

points. According to the commenter, this simplistic method insufficiently characterized 

the spatial distribution of source emissions at the mill, and would be expected to result in 

overestimates of off-site concentrations and associated risk.

 The commenter found that about 26 percent of the mills (11 of 42) had incorrectly 

located one or more of the sources that contributed substantially to the modeled risk. The 

commenter expected that more accurately locating these sources would result in lower 

modeled risk.

 The commenter found that 3 of the 42 mills had maximum modeled risk at a populationbased receptor that was erroneously placed in an uninhabited and inaccessible location 

close to a major emissions source.

 The commenter found that about 26 percent of the mills (11 of 42) had erroneously

calculated emissions, input the total facility emissions for a category into multiple 

sources rather than the contribution of each source, or used an emission factor based on 

questionable data. The commenter expected that more accurately locating these sources 

would result in lower modeled risk.

 The commenter found that about 19 percent of the mills (8 of 42) had characterized 

sources with very low or default fugitive release heights. According to the commenter, 

this simplistic method insufficiently characterized the dispersion of these source 

emissions at the mill, and would be expected to result in overestimates of off-site 

concentrations and associated risk.

The commenter also noted that, for several mills, the input data used in EPA’s risk 

assessment were incorrect and indicated that those mills intend to submit corrected or updated 

data to EPA. The commenter included the following examples of data corrections:

 The commenter found that HEM input data were off several orders of magnitude, due to 

either mistakes in the NEI submittals or transcription errors from the NEI to the HEM 

model.

 The commenter found that some facilities did not submit an updated NEI to EPA based 

on revised bleached paper machine emission factor data issued by NCASI in late June 

2011.

 The commenter found that unrepresentative meteorological data were used in the HEM 

assessment.

Based on the findings highlighted above and discussions with facility personnel, the 

commenter expected that the HEM risk results reported by EPA are in general higher than the 

actual risk for the industry that would be modeled if appropriate modeling refinements and 

corrections were made. The commenter pointed out that, even with these errors, EPA determined 

that the remaining residual risk levels were acceptable. As a result, the commenter realized that 
44

EPA may decide it is not necessary to rerun the HEM model and update the risk assessment at 

this time. The commenter wanted to note, however, that the correction of the identified errors 

would result in lower estimated risks for pulp and paper mills at current emission rates.

Response: Most of the comments provided pertain to mischaracterizations of emissions 

and release parameters by industry. The EPA believes the data provided for the modeling run 

were of sufficient accuracy to characterize the risk for the source category. We received a 

number of post-proposal NEI data revisions from the pulp and paper industry that address the 

commenter’s concerns about errors in model input parameters, as summarized in the paragraphs 

below.

Of the mills with maximum acute HQs of 1.5 and greater, there were 3 mills that 

commented about the incorrect location of receptors, a fourth that requested a change to the 

fugitive angle for their wastewater treatment source, and a fifth that submitted latitude/longitude 

corrections for their wastewater treatment source.

Of the 42 mills with a maximum individual lifetime cancer risk of 2 in a million or 

greater that provided post-proposal NEI data revisions, there were 8 mills that revised the 

emissions release point type from “fugitive” to “stack” for various sources at the mills (e.g., 

papermaking, pulping, causticizing) and 4 additional mills that replaced their paper machine 

records with new records to account for stack emissions, wet/dry end emissions, all vents on the 

machine, etc. There were 12 mills that corrected the latitude/longitude values for their paper 

machines, wastewater treatment sources, pulping sources, and causticizing sources and 10 mills 

that requested changes to receptor locations. There were 26 mills that either reduced emissions 

(e.g., based on updated/corrected emission factors) or deleted pollutants (e.g., deleting HCE from 

bleaching/washing in accordance with NCASI guidance, deleting organic pollutants not expected 

from causticizing systems using fresh water). There were also 7 mills that increased the stack 

height for some of their sources when they changed the release point type for those sources from 

“fugitive” to “stack.”

Following the review of the NEI data revisions, a determination was made on a mill-bymill basis whether risk remodeling was needed for a particular mill (i.e., whether the NEI 

revisions would influence the outcome of the proposed risk assessment results). This

determination was premised on the finding in the December 27, 2011 subpart S proposal that the 

risks from the pulp and paper source category are acceptable, and the current standard protects 

public health with an ample margin of safety. Therefore, as long as the risk for an individual mill 

would not be expected to increase substantially as a result of the mill’s NEI data revisions, 

remodeling was not recommended for that mill.

Based on our review, we have concluded that the results of remodeling risk would most 

likely adjust the risk results for the subpart S source category downward (i.e., reduce risk).

Nearly all of the mills that submitted NEI data revisions appear to have reduced their risk by

reducing emissions, changing emission release point type from fugitive to stack, and/or changing 

stack/fugitive parameters, among other changes. For the few mills that increased emissions with 

their NEI data revisions, the mills already had chronic cancer risks at or below 1 in a million and 

acute non-cancer risks below 1, and any increase in risk was expected to be minimal. For the 

several mills that made parameter changes that could potentially increase risk, any increase in 
45

risk was countered by other changes that could reduce risk (e.g., making other parameter 

changes, changing release point type from fugitive to stack, and/or reducing emissions), and the 

mills already had chronic cancer risks below 1 in a million, acute cancer risks below 1, and no 

increase in emissions of risk driver pollutants for their subpart S processes.

Based on these findings, EPA has elected not to remodel risk for purposes of 

promulgating of the subpart S residual risk review, but instead to rely on the conclusions from 

the risk modeling conducted for the proposed rule. A memo for the docket has been prepared 

summarizing the NEI revisions, noting their likely effect on risk, and documenting the 

recommendation not to remodel risk.57

35. Comment: Commenter 0218 declared that the EPA failed to assess or account for the 

increased exposure and vulnerability of children and pregnant women. The commenter observed

that biological differences in the developing child and fetus can result in increased cancer and 

non-cancer risk due to both increased exposure and increased vulnerability, and emphasized that 

the EPA must account for the increased susceptibility of children to HAP emissions from this 

source category in the risk assessment. The commenter stated that the most recent review of EPA 

risk assessment practices by the NAS explicitly advised EPA to include in utero exposures as a 

period of increased sensitivity to carcinogens, and the commenter cited evidence from the most 

recent California draft risk assessment guidelines recommending assessment of health risk due to 

breast milk exposure as well as dermal and other ingestion exposures. The commenter noted that 

studies indicate increased risk from early life exposures for carcinogens not acting by a 

mutagenic mode of action and increased susceptibility during early life exposures for non-cancer 

effects, where physiological differences in the developing organism result in increased risks. 

Commenter 0218 listed seven HAPs (formaldehyde, benzene, methylene chloride, POM, 

hexavalent chromium, arsenic, and cadmium) of particular concern that should be evaluated for 

increased early-life susceptibility. The commenter discussed each HAP’s dangers, listed multiple 

journal articles, and cited attachments to the comment letter to support the commenter’s

statements. 

The commenter suggested that the EPA should adopt the CalEPA OEHHA childprotective scientific approach on cancer and other pollutants, and use at least an additional 10-

fold uncertainty factor to protect children. The commenter stated that the EPA must follow the 

lead of OEHHA by using age-dependent adjustment factors for all carcinogens emitted by this 

source, including hexavalent chromium, acetaldehyde, formaldehyde, HCE, benzene, 

naphthalene, vinyl chloride, and others. The commenter asked that the EPA update its list of 

carcinogenic HAPs that act by a mutagenic mode of action to include more recent evaluations of 

carcinogenic modes of action and to account for increased cancer risk resulting from prenatal 

exposures. The commenter suggested that the EPA use the OEHHA age-dependant adjustment 

factors and assess exposure during fetal development; use an additional factor, similar to 

OEHHA’s 10X adjustment factor for cancer risk due to prenatal to 2 year exposures, to address 

 

57 See memorandum from T. Holloway, RTI, to J. Bradfield, B. Schrock, K. Spence, and N. Swanson, EPA. 

Recommendations Concerning Residual Risk Remodeling for the Pulp and Paper Industry, May 8, 2012, in the 

docket for the subpart S rulemaking.
46

early life exposure in its risk assessment; and to use adjustment factors for all carcinogens in 

assessing health risk for children and pre-natal exposure.

The commenter asked that the EPA use OEHHA child-specific reference doses to assess 

chronic noncancer and acute health risk, where they are available, including for cadmium, 

manganese, and nickel, as well as the lead benchmark. The commenter observed that the EPA 

has the scientific ability to translate these reference doses for oral, inhalation, and other pathway

assessments.

The commenter proposed that the EPA apply at least a 10-fold margin of safety factor to 

protect children in these rulemakings, in addition to the uncertainty factors it already uses, when 

a child-specific reference value or vulnerability information is not available. The safety factor 

should be applied as well for chronic (non-cancer) and acute health risk, according to the 

commenter.

The commenter recommended that the EPA consult with multiple scientific bodies on the 

scientific basis of the proposed rulemaking, and noted that adopting the OEHHA guidelines on 

age-dependent adjustment factors and child-specific reference doses and accounting for the 

greater exposure and vulnerability of children would be consistent with the SAB’s

recommendations. The commenter observed that Congress recognized this science in toxics 

legislation in 1996, the Food Quality Protection Act (FQPA) for pesticide chemical residue, 

where Congress used a 10-fold margin of safety for infants and children.

The commenter provided a table of comparisons between OEHHA child-health reference 

values and those of EPA. The commenter provided references for the statements in this comment 

as attachments to the comment letter, and as citations in footnotes.

Response: The EPA disagrees with the commenter’s statement that this risk assessment 

underestimates risk to children and lacks consideration of early-life susceptibility. The EPA 

agrees that biological differences across life stages may lead to differences in the susceptibility to 

HAP, as can differences among population groups due to pre-existing disease states or other 

factors. Accordingly, the methods we use in risk assessments have taken this into account. For 

the dose-response component of HAP assessments for RTR, the EPA uses exposure reference 

concentrations and unit risk estimates that are expressly derived with the objective of protecting 

sensitive populations and lifestages, including children.58 For example, a review of the chronic 

reference value process concluded that the Agency’s RfC derivation process adequately 

considered potential susceptibility of different subgroups with specific consideration of children, 

such that the resultant RfC values pertain to the full human population, including “sensitive 

subgroups,” which are inclusive of childhood. Cancer risk assessments are performed in 

accordance with EPA’s Supplemental Guidance.59 This Guidance recommends the application of 

age-dependent adjustment factors for assessing cancer risk from carcinogenic pollutants 

 

58 See U.S. EPA. (2002), A Review of the Reference Dose and Reference Concentration Processes. EPA/630/P02/002F. Risk Assessment Forum, Washington DC. Available online at 

http://www.epa.gov/raf/publications/pdfs/rfd-final.pdf.

59 See U.S. EPA. (2005), Supplemental Guidance for Assessing Susceptibility from Early-Life Exposure to 

Carcinogens. EPA/630/R-03/003F. Washington, DC. Available online at: 

http://www.epa.gov/cancerguidelines/guidelines-carcinogen-supplement.htm.
47

concluded to act via a mutagenic mode of action and for which information on early-life 

susceptibility is lacking. The basis for this methodology is provided in the 2005 Supplemental 

Guidance. With regard to other carcinogenic pollutants for which early-life susceptibility data 

are lacking, it is the Agency’s long-standing science policy position that use of the linear lowdose extrapolation approach (without further adjustment) provides adequate public health 

conservatism in the absence of chemical-specific data indicating differential early-life 

susceptibility or when the mode of action is not mutagenicity.

60

The EPA disagrees with the commenter statement that that EPA should use California 

EPA’s child specific-reference doses for school site risk assessments61 in order to address the 

potential for early-life susceptibility. The EPA methods for assessing hazard and dose-response 

relationships for HAPs and developing RfCs and cancer risk estimates, as noted above, 

specifically address the potential for early-life susceptibility. Whenever data indicate increased 

susceptibilty of a developmental lifestage or of a population group, those data are factored into 

the analysis. When data are inadequate to understand the effects of a specific pollutant on 

sensitive subpopulations, which for some pollutants may include children, the Agency’s risk 

assessment methods take that into account to ensure that resulting assessments address the 

possibility that such subpopulations might be more or less sensitive. Further, in the RTR risk 

assessments performed using the agency’s preferred dose-response values, exposure is 

characterized as occurring all day, every day over a lifetime, rather than only during specific 

periods of time during childhood. In addition, the EPA has a hierarchy of appropriate health 

benchmark values and in general, this hierarchy places greater weight on the EPA derived health 

benchmarks than those from other agencies (see 

http://www.epa.gov/ttn/atw/nata1999/99pdfs/healtheffectsinfo.pdf). Notably, this hierarchy 

favoring EPA benchmarks (when they exist) over all others has been endorsed by the SAB.

36. Comment: Commenter 0218 stated that EPA has failed to provide a reasoned 

explanation for its proposed determination that the current level of health risk for the pulp and 

paper source category is acceptable, and that the EPA should find health risk from this source 

category to be unacceptable under section 112(f)(2). 

The commenter argued that the EPA has not adequately justified its proposed 

determination that health risk is acceptable, given the EPA’s findings of cancer risk that is 10 

times the target of section 112(f)(2), i.e., 10-in-1 million (based on allowable emissions), an 

acute health risk of 20, which is 10 times EPA’s own safety threshold, a TOSHI of 0.6 (based on 

allowable emissions), and that this source category emits PB-HAPs, including one (POM) which 

poses a multipathway risk that is 2 times EPA’s threshold. The commenter stated that in the 

NESHAP for ferroalloys production (76 FR 72508), the EPA found the combination of cancer 

 

60 Id.

61 We note that California EPA’s use of these numerical values, which do not exist for inhalation exposures, is 

limited to the context of risk assessment at proposed or existing California school sites and does not extend to their 

Air Hot Spots Risk Assessment program. Further the guidance for the California EPA school site assessment 

program specifies the use of California OEHHA or U.S. EPA IRIS values in the absence of the school site risk 

assessment child-specific values (Cal OEHHA, Guidance for School Site Risk Assessment Pursuant to Health and 

Safety Code Section 901(f): Guidance for Assessing Exposures and Health Risks at Existing and Proposed School 

Sites, Final Report, February 2004, available online at: 

http://www.oehha.ca.gov/public_info/public/kids/pdf/SchoolscreenFinal.pdf). 
48

risk of 80-in-1 million actual/100-in-1 million allowable and chronic non-cancer TOSHI of 90 

actual/200 allowable to be “unacceptable.” The commenter recommended that the EPA should 

do the same here, because there is both a high cancer and acute health risk for this source 

category.

The commenter also asserted that the EPA’s risk assessment does not provide a full 

picture of the true risk, citing omissions in the EPA’s risk assessment and uncertainties, such as a 

lack of accounting for the additional health risk to children and pregnant women, a lack of 

reference values for some pollutants, and failure to assess risk from malfunctions or violations. 

The commenter argued that all of these gaps mean that it is uncertain how much the EPA 

underestimated risk, and the EPA should find the health risk from this source category to be 

“unacceptable.” The commenter concluded that because EPA’s risk assessment and acceptability

determination fail to address or consider important elements of the emissions, exposure, and 

health risk, EPA’s analysis is incomplete, unlawful, and arbitrary and capricious.

Response: Pollutant-specific RfCs are not absolute thresholds, but estimates of chronic 

inhalation exposures, at or below which health effects would not be expected to occur, including 

in sensitive subgroups. We further note that these RfCs are developed using a health-protective 

approach62 and that TOSHI values of 1 or less are (like RfC levels) generally considered to carry 

no appreciable risk of adverse health effects. We further note that we generally draw no bright 

lines of acceptability regarding cancer or noncancer risks from source category HAP emissions, 

and that it is always important to consider the specific uncertainties of the emissions and health 

effects information regarding the source category in question when deciding exactly what level 

of cancer and noncancer risk should be considered acceptable. In addition, the source categoryspecific decision of what constitutes an acceptable level of risk should be a holistic one; that is, it 

should simultaneously consider all potential health impacts--chronic and acute, cancer and 

noncancer, and multipathway--along with their uncertainties, when determining the acceptable 

level of source category risk. Experience with source category rulemakings in the past tells us 

that this means that drawing bright lines for such decision-making is impossible. The Benzene 

NESHAP decision framework of 1989 acknowledged this; in today’s world, such flexibility is 

even more imperative, because new information relevant to the question of risk acceptability is 

being developed all the time, and the accuracy and uncertainty of each piece of information must 

be considered in a weight-of-evidence approach for each decision. This relevant body of 

information is growing fast (and it will continue to grow faster and faster), necessitating a 

flexible weight-of-evidence approach that acknowledges both complexity and uncertainty in the 

simplest and most transparent way possible. While this challenge is formidable, it is nonetheless 

the goal of the EPA’s RTR decision-making, and it is the goal of the risk assessment to provide 

the information to support the decision-making process. 

In this case, considering all the available risk information and the uncertainties associated 

with that risk information, risk was found to be acceptable. However, as is the case for all RTR 

reviews, as part of the second step ample margin of safety analysis, we did look for additional 

controls and process improvements that might further reduce risks in a cost-effective, technically 

feasible manner. In this case however, we didn't find any such controls. 

 

62 See section 4.2 (uncertainty discussion) in U.S. EPA’s Risk Assessment for the Pulp & Paper Source Category, in 

the docket for the subpart S rulemaking.
49

With respect to the potential for multipathway risk, we note that the results referenced by

the commenter were from a worst-case screening scenario and do not indicate that adverse 

multipathway effects are going to occur. The EPA has since developed a refined emission 

screening thresholds using TRIM.FaTE. This refined approach uses; (1) improved toxicity

rating/scaling methods for POMs and dioxin congeners; (2) improved fate, transport, and uptake 

behavior thru the aquatic food chain; and (3) updated fish and soil ingestion rates. The above 

changes resulted in a higher screening threshold for emissions of POMs, resulting in the PBHAP emissions being below the screening threshold by a factor of 9 and below a risk screening 

scenario with an excess cancer risk of 1 in a million.63

It would be inappropriate for EPA to add a screening threshold exceedance as an estimate 

for multipathway risks with the modeled inhalation risks. The screening threshold is not intended 

to be used to produce quantitative estimates of actual or potential risk. Rather, it provides a basis 

for determining if residual human health risks are of potential concern. The screening thresholds 

are based upon a worst-case scenario, which may not even be applicable to the site, depending 

upon geography and release parameters for those pollutants that are PB-HAPs. 

Addressed elsewhere in this document are the commenter’s concerns about the additional 

health risk to children and pregnant women (see the previous response), the lack of reference 

values for some pollutants (see the first response in section 4.2.5), and assessing risk from 

malfunctions or violations (see the third response in section 4.2.3).

37. Comment: Commenter 0218 recommended that EPA find the cancer risk from this 

source category to be “unacceptable,” reduce cancer risk to a lower level, and aim to achieve a 

cancer risk below 1-in-1 million, as that is the statutory target of section 112(f)(2).

The commenter disagreed with the EPA’s basing of its acceptability determination on the 

outdated presumptive limit (100-in-1 million) of what level of cancer risk is acceptable, which is 

based on the “presumptive limit” of acceptability that EPA created in the 1989 Benzene Rule. 

The commenter stated that the EPA has not adequately explained why it is not requiring 

additional emission reductions that would further reduce cancer risk to ensure an acceptable level 

of risk in today’s world. The commenter noted that significant reasons exist for EPA to set a 

lower presumptive level of risk acceptability, including the need to better protect children, as 

well as knowledge of the grave health risks at stake for local communities and the need for 

environmental justice (EJ). The commenter observed that science, pollution controls, and societal 

values and standards of fairness–including a new commitment to EJ–have all advanced 

dramatically in recent years and since the 1980s. To bolster the commenter’s argument, the 

commenter listed multiple milestones that have occurred since the 1988 presumptive 

benchmarks, including the 1990 CAA amendments, EO 12898 on Environmental Justice, EO 

13045 on Children’s Environmental Health, and other findings and determinations regarding 

children’s health. The commenter stated that applying the acceptability presumption developed 

from the 1988 document is arbitrary and capricious for the following reasons:

 

63 For more information on the changes made to the PB-HAP screening thresholds, refer to U.S. EPA’s Residual 

Risk Assessment for the Pulp & Paper Source Category, Appendix 4, “Overview of Tiered Approach to Assessing 

Multipathway Exposures for RTR,” in the docket for the subpart S rulemaking.
50

 The CAA requires an up-to-date contemporary assessment; section 112(f)(2) directs the 

EPA to assess and address risk remaining to public health and the environment 8 years 

after the MACT standard is in place, a inherent direction to take account of new 

circumstances;

 There is significant new information on the factors the EPA discussed in its old 

rulemaking that should influence its analysis of what level of risk is currently

“acceptable”;

 Scientific research has evolved dramatically since the EPA set that presumption. The 

commenter cited risk assessment studies and guidance, studies on children’s exposure to 

toxics, and CDC reports as providing evidence of the EPA and other federally funded 

research and developments in health effects of chemicals (examples were provided as 

attachments to the commenter’s letter);

 The EPA’s commitment to EJ must inform its consideration of what level of risk is 

“acceptable,” as required by the 1994 Environmental Justice EO and 2010 guidance to 

direct all federal agencies to take EJ into consideration; and

 American values and policies have evolved to tolerate less health risk from industrial 

pollution since the 1988 Survey, and Congress amended the CAA after the 1988 study to 

reduce deaths and human health risks from air pollution, presumably because it did not 

consider the risk of death from air pollution at that time to be acceptable.

Response: Based on Response from Primary Lead p. 12 As an initial matter, we note that 

in 1990, Congress codified in section 112(f) of the CAA the decision approach we use for 

interpreting our residual risk analyses (i.e., the Benzene NESHAP, 54 FR 38044). Under that 

approach, the 100-in–a-million cancer risk is not a bright line indicating that risk is “acceptable,” 

but rather we consider this health metric in conjunction with a variety of health factors to 

determine whether the risk is acceptable. Where we conclude that the risk is not acceptable, we 

cannot consider costs in requiring controls to bring risks down to an acceptable level. However, 

the analysis of whether risk is acceptable is not the endpoint. Once we determine that controls 

are sufficient to ensure risk is acceptable, we again review the health metrics in conjunction with 

considering the costs of controls to determine whether additional controls should be required to 

provide an ample margin of safety.

Moreover, the commenter does not support their contention that people are now 

unwilling to accept a level of risk that was acceptable at the time the CAA was amended in 1990. 

Nor does the commenter support how science has evolved in a way that would undermine the 

codified framework for determining acceptability. We note that, for purposes of the proposed 

rule, relative to EJ issues, we performed a demographic analysis for the purpose of informing the 

public, and that analysis is in the docket.64

38. Comment: Commenter 0218 stated that EPA should reduce the threshold of what cancer 

risk is presumed to be acceptable, and find the cancer risk in the proposed rule to be 

unacceptable. The commenter observed that although the HON decision found that EPA was not 

required to achieve a lifetime cancer risk of 1-in-1 million, that decision recognized that EPA has 

 

64 See U.S. EPA’s OAQPS Environmental Justice Analytical Team Report, in the docket for the subpart S 

rulemaking.
51

full authority to protect public health by reducing risk to a lower level, and the decision did not 

authorize EPA to continue presuming forever that any lifetime cancer risk between 1-in-1 

million and 100-in-1 million is acceptable. The commenter observed that references to the 

Benzene Rule in section 112(f) also do not give EPA blanket authorization to avoid updating the 

Benzene Rule approach forever (See 42 U.S.C. 7412(f)(2)(B) [stating that 112 provision shall 

not “be construed as affecting, or applying to” EPA’s interpretation of the statute as set forth in 

the Benzene Rule, 54 FR 38044], and 7412(f)(2)(A) [referring to the Benzene Rule]).

Response: We do not consider the 1-in-1 million MIR level as a ‘bright line’ mandated 

level of protection for establishing residual risk standards. In determining the ample margin of 

safety (i.e., the level of the standard), health risk is one factor that we must consider, along with 

other factors such as cost and technological feasibility. Balancing these and other factors with the 

ability to achieve meaningful risk reduction is a critical component of the residual risk 

rulemaking process. The major contributors to this risk are HCE and naphthalene from kraft 

processes such as pulp storage, wastewater, and bleaching. In general, the contribution of the 

source category to elevated facilitywide cancer or noncancer risks is low throughout the facilities 

in this source category. The maximum facility-wide MIR is 30 in a million, with the pulp and 

paper source category (MACT code 1626-1) contributing 27 percent of the risk. The remaining 

63 percent is driven by emissions of arsenic and chromium (VI) from hazardous waste 

incineration. The maximum facility-wide TOSHI is 2, driven by emissions of antimony

compounds from kraft SDT process units. The pulp and paper source category (MACT code 

1626-1) contributes approximately 11 percent to the facility-wide TOSHI.

39. Comment: Commenter 0225 stated that in their community, the largest polluter is Port 

Townsend Paper Corporation (PTPC). Extensive health impacts are suffered from the pollutants 

emitted at the mill site, including, but not limited to, respiratory distress, seizures, and chronic 

asthma. The commenter stated there were strong smells emanating from the mill. The commenter 

expressed concern about the increased health impacts from those individuals at the nearby school 

and hospital.

Commenter 0225 rejected the acceptable risk levels, as determined in the Benzene 

NESHAP, as acceptable in the commenter’s area of residence. The commenter attached two 

documents citing Washington Cancer Registry Figures (see commenter attachments 0225.2 and 

0225.3), stating that Port Townsend/Jefferson County WA is in the top 3 of 39 Washington

counties for 11 out of 24 types of cancer. The commenter contended that if the mill is operating 

within legal limits, those established limits are too high.

Response: The final residual risk assessment for the subpart S NESHAP RTR is 

available in the docket and at http://www.epa.gov/ttn/atw/pulp/pulppg.html. It is unclear whether 

the commenter is referring to emissions from sources that were subject to this review or other 

regulated emissions from the facility. Appendix 5 in the assessment provides all of the risk 

impact information for each individual site in the pulp and paper category, including Port 

Townsend Paper Corporation, NEI ID NEI42357. The conclusion of our assessment was that the 

risk associated with HAP emissions from all facilities in this category is acceptable. As part of 

the information collection activity associated with the rule development, we collected and 

reviewed operating permits issued to facilities in the industry. Like other industry facilities, the 

Port Townsend mill is subject to regulations other than section 112 NESHAP (e.g., New Source 
52

Performance Standards (NSPS) for Kraft Pulp Mills, 40 CFR part 60 subpart BB), and the mill 

has agreed to permit conditions for regulated pollutants (e.g., total reduced sulfur [TRS]) that 

were not subject to this regulatory review but will be reviewed in the future.

40. Comment: Commenter 0218 asserted that EPA should find the acute health risk from the 

pulp and paper source category to be unacceptable under section 112(f)(2). The commenter 

observed that in the EPA’s 2004 risk assessment documentation, the EPA stated that an HQ of 1 

or less indicates a safety threshold for EPA for both chronic non-cancer and acute health effects, 

and when an HQ value is more than 1, additional information is used to determine if there is a 

potential for significant acute risk. The commenter disagreed with the EPA’s determination that 

with an acute HQ of 20, risk is acceptable. Additionally, the commenter observed, the EPA’s

acute health risk number did not include the combined acute health risk that can occur due to 

multiple pollutant emissions simultaneously in an acute health incident and did not assess 

facility-wide acute health risk, and the EPA did not assess the acute health risk based on 

allowable emissions.

Response: As noted in a previous response, we generally draw no bright lines of 

acceptability regarding cancer or noncancer risks from source category HAP emissions, and it is 

always important to consider the specific uncertainties of the emissions and health effects 

information regarding the source category in question when deciding exactly what level of 

cancer and noncancer risk should be considered acceptable. In addition, the source categoryspecific decision of what constitutes an acceptable level of risk should be a holistic one; that is, it 

should simultaneously consider all potential health impacts--chronic and acute, cancer and 

noncancer, and multipathway--along with their uncertainties, when determining the acceptable 

level of source category risk. Experience with source category rulemakings in the past tells us 

that this means that drawing bright lines for such decision-making is impossible. In this case, 

considering all the available risk information and the uncertainties associated with that risk 

information, risk was found to be acceptable. However, as is the case for all RTR reviews, as 

part of the second step ample margin of safety analysis, we did look for additional controls and 

process improvements that might further reduce risks in a cost-effective, technically feasible 

manner. In this case however, we didn't find any such controls. In addition, it should be noted 

that the max off-site HQ was actually 15, which was rounded to 20, and the HQ (AEGL-1) was 

0.4. For a location in which people reside, the HQ (REL) was actually only 2.

We disagree with the commenter that EPA should create a combined acute risk number 

that would represent the total acute risk for all pollutants that act in a similar way on the same 

organ system or systems (similar to the chronic TOSHI). As noted in previous responses, the 

worst-case acute screen is already a conservative scenario. That is, the acute screening scenario 

assumes worst-case meteorology, peak emissions for all emission points occurring currently and 

an individual being located at the site of maximum concentration for an hour. Thus, as noted in 

section 2.72 of the risk assessment document65: “because of the conservative nature of the acute 

inhalation screening and the variable nature of emissions and potential exposures, acute impacts 

were screened on an individual pollutant basis, not using the TOSHI approach.”

 

65 See U.S. EPA’s Residual Risk Assessment for the Pulp & Paper Source Category, in the docket for the subpart S 

rulemaking.
53

41. Comment: Commenter 0218 disagreed with the EPA’s acceptability determination for 

chronic non-cancer health risk. The commenter urged the EPA to not assume that 1 is an 

acceptable level of chronic non-cancer risk from a single major air toxics source category. The 

commenter observed that the EPA failed to account for the greater risk to children and due to

early exposure and did not assess cumulative toxic air health risk.

The commenter stated that by finding that a non-cancer TOSHI of 1 or below is not a 

human health concern, EPA has arbitrarily ignored its staff’s past scientific assessment of this 

issue, in the 2002 internal memo Residual Risk Program: Selection of Hazard Index Limits, 

where EPA stated that the default HI limit for chronic non-cancer risks should be well under 1.0 

for individual sources—specifically, staff then recommended that it should be no higher than 0.2. 

The commenter recommended that the EPA reduce the TOSHI presumptive acceptability

threshold to 0.2 or below to ensure that EPA is fully protecting the most-exposed people in local 

communities exposed to multiple sources and types of toxic air pollution.

The commenter expressed concern that the EPA conceded that the TOSHI itself “may

have been underestimated,” in a statement, confusing to the commenter, that only says that 

“impacts on organs or systems that occur above the critical dose have not been included in the 

TOSHI calculations.” The commenter observed that this is a dramatic way of underestimating 

risk, in that if EPA takes out impacts that are occurring above the critical dose, EPA is ignoring 

health risk that has already reached an unacceptable level. The commenter stated that this has no 

rational basis and demonstrates that EPA must reduce the TOSHI.

According to the commenter, the EPA’s facility-wide risk that shows a TOSHI of 2 and 

contribution of 11 percent of the risk from this source category is a significant contribution. The 

commenter asserted that the EPA must reduce the TOSHI for the pulp and paper source category

because it is contributing over 10 percent of the facility-wide risk, which is 2 times EPA’s own 

threshold.

The commenter further argued that the EPA has not combined its risk analyses, but has 

listed them all together and treated them as separate types of risk, which is unlawful, arbitrary, 

and capricious, and it undermines EPA’s acceptability determination. The commenter stated that 

EPA has failed to justify how the chronic non-cancer risk number could be acceptable when 

combined with all of the other kinds of health risks that EPA has found, including high cancer 

risk (that is, above 1-in-1 million), multipathway risk, and high acute risk.

Response: Based on Bin 1 Response. The EPA has not used a TOSHI value of 0.2 as a 

default upper limit for acceptable chronic noncancer risk in RTR rule making. In determining 

whether to require additional standards, non-cancer risks are considered in addition to cancer 

risks and other health measures and factors. A TOSHI of 1.0 is not considered a rigid line for 

acceptability, and we weigh this value with other health measures and factors in both the 

decision regarding risk acceptability and in the ample margin of safety determination. In regards 

to facility-wide risk, if a source category contributes significantly to elevated facility-wide noncancer risks, we may consider whether additional standards should be required to reduce those 

risks.
54

42. Comment: Commenter 0218 stated that the EPA has failed to explain its conclusion that 

multipathway risk is “acceptable.” The commenter asserted that the EPA failed to fully assess 

multipathway health risk (for multiple reasons listed in other comments) and to combine health 

risks to assess the cumulative risk burden. The commenter suggests that as a result of this high 

multipathway risk, the most exposed person will face a total cancer risk that is above the cancer 

risk the EPA described in the preamble, though it is unclear by how much more because the EPA 

has not provided the risk data needed to inform this. According to the commenter, the EPA must 

require further reductions in multipathway risk to achieve an acceptable level.

Response: EPA developed the scenario in the multipathway screen in order to estimate 

the upper end of the range of individual, long-term, non-inhalation exposures for situations likely

to be encountered in the United States. The approach is described in the “Overview of Tiered 

Approach to Assessing Multipathway Exposures for RTR,” available as Appendix 4 to the risk 

assessment document in the docket for the subpart S rulemaking.66

Since proposal, EPA has refined the emission screening thresholds, which use 

TRIM.FaTE. These refinements include: (1) improved toxicity rating/scaling methods for 

chemical specific POMs and dioxin congeners to account for their individual fate and transport 

properties versus using the fate and transport properties of benzo(a)pyrene and 2,3,7,8-TCDD; 

(2) improved fate, transport, and uptake behavior through the aquatic food chain; and (3) updated 

fish and soil ingestion rates from EPA’s 2011 Exposure Factors Handbook.

67 These changes 

resulted in a revised screening threshold for emissions of POM, which results in the POM 

emissions for all pulp and paper facilities being below the screening threshold. When considered 

along with the results from the inhalation assessment (where the highest risk was 10 in a 

million), we determined that the risks from POM emissions for the source category were low.68

43. Comment: Commenter 0218 recommended that the EPA aggregate health risk for the 

source category and decide whether the total health risk from each pollutant or from all 

pollutants combined is unacceptable, and to not do so is arbitrary and capricious. The commenter 

stated that the EPA is required to assess a community’s total exposure to toxic air pollution, in 

context, to decide how much additional pollution protection is needed from this source category, 

i.e., the source category’s necessary amount of reduction. The commenter asked that the EPA 

aggregate risk from multiple sources of pollution, multiple pollutants, and recognize background 

levels of past exposure that increases current health risk to create a combined health risk metric 

that accounts for synergistic effects. The commenter believes that by not performing a full, 

cumulative risk assessment, EPA failed to demonstrate that the risk remaining under its proposed 

rule would be “acceptable.” The commenter stated that the EPA must combine the health risks 

and address them together as a whole cumulative health burden to satisfy its legal duty under 

section 112(f)(2), and to consider all health risks to the most-exposed person, combined, from 

this source category.

 

66 See U.S. EPA’s Residual Risk Assessment for the Pulp & Paper Source Category, Appendix 4, “Overview of 

Tiered Approach to Assessing Multipathway Exposures for RTR,” in the docket for the subpart S rulemaking.

67 See U.S EPA, Exposure Factors Handbook: 2011 Edition; EPA/600R-090/052F; available online at: 

http://www.epa.gov/ncea/efh/pdfs/efh-complete.pdf

68 For more information on the changes made to the PB-HAP screening thresholds, refer to U.S. EPA’s Residual 

Risk Assessment for the Pulp & Paper Source Category, Appendix 4, “Overview of Tiered Approach to Assessing 

Multipathway Exposures for RTR,” in the docket for the subpart S rulemaking.
55

Response: The EPA addressed the aggregate health risk for the source category by

conducting an assessment of the cumulative cancer risks from emitted carcinogens and the 

cumulative noncancer HIs from all emitted non-carcinogens affecting the same target organ 

system for both the source category emissions and the facility-wide emissions. This assessment

excluded background contributions from HAPs as well as PB-HAPs. While the incorporation of 

additional background concentrations from the environment in our risk assessments including 

those from the past and future (mobile sources and other industrial and area sources) could be 

technically challenging, they are neither mandated nor barred from our analysis. In developing 

the decision framework in the Benzene NESHAP69 currently used for making residual risk 

decisions, EPA rejected approaches that would have mandated consideration of background 

levels of pollution in assessing the acceptability of risk, concluding that “comparison of 

acceptable risk should not be associated with levels in polluted urban air” (54 FR 38044, 38061, 

September 14, 1989). Background levels of certain HAPs can be relatively high, perhaps even 

above a level that might be considered “safe.” Background levels (including natural background) 

are not barred from EPA‘s AMOS analysis, but EPA may consider them, as appropriate and as 

available, along with other factors, such as cost and technical feasibility, in the second step of its 

112(f) analysis. In this analysis, background levels were not considered because it is technically 

infeasible. This is because for this source category, technical limitations in the data set for this 

source category make it insufficient to create a reliable analysis.

44. Comment: Commenter 0218 stated that EPA failed to combine risks from multiple HAP 

and pathways and thus failed to assess cumulative impacts and health risk. In order to satisfy

section 112(f)(2), the commenter contended that the EPA should:

 Create a combined acute risk number that would represent the total acute risk for all 

pollutants that act in a similar way on the same organ system or systems, similarly to the 

chronic TOSHI;

 Perform a cumulative risk assessment that combines inhalation and multipathway risk for 

each pollutant, including pollutants such as cadmium, arsenic, mercury, and lead that 

cause both types of risk;

 Create any metric to assess the total, combined health risk that could be used to assess the 

cumulative impact of all of the types of risks and to view risks as a single cumulative 

burden.

Response: We disagree with the commenter that EPA should create a combined acute 

risk number that would represent the total acute risk for all pollutants that act in a similar way on 

the same organ system or systems (similar to the chronic TOSHI). As noted in previous 

responses, the worst-case acute screen is already a conservative scenario. That is, the acute 

screening scenario assumes worst-case meteorology, peak emissions for all emission points 

occurring currently and an individual being located at the site of maximum concentration for an 

hour. Thus, as noted in section 2.72 of the risk assessment document: “because of the 

conservative nature of the acute inhalation screening and the variable nature of emissions and 

potential exposures, acute impacts were screened on an individual pollutant basis, not using the 

 

69 National Emission Standards for Hazardous Air Pollutants: Benzene Emissions from Maleic Anhydride Plants, 

Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene Equipment Leaks, and Coke By-Product Recovery 

Plants (54 FR 38044, September 14, 1989) (Benzene NESHAP).
56

TOSHI approach.”

70 In the future, we will, continue to refine various aspects of our acute 

assessments as methods improve and more data become available. Attendent to such 

improvement will be a reconsideration of whether to use TOSHI in our acute assessments.

It would also be inappropriate for EPA to add a screening threshold exceedance as an 

estimate for multipathway risks with the modeled inhalation risks. The screening threshold is not 

intended to be used to produce quantitative estimates of actual or potential risk. Rather, it 

provides a basis for determining if residual human health risks are of potential concern. The 

screening thresholds are based upon a worst-case scenario, which may not even be applicable to 

the site, depending upon geography and release parameters for those pollutants that are PBHAPs. Failure of a screen could result in a decision for facility-specific multipathway

assessments being undertaken.

45. Comment: Commenter 0218 maintained that the EPA must incorporate a margin of 

safety (or uncertainty) factor to account for a history of exposure or exposure to additional 

emissions beyond each source category under review. The commenter stated that the EPA should 

account for the history of exposure to toxic air pollution and for ongoing exposure to the source 

category’s toxic air emissions combined with other HAP emissions from multiple sources, by

applying additional safety factors in its acceptability determination.

The commenter suggested that the EPA apply an uncertainty factor based on the number 

of other facilities contributing HAP exposure risks; thus, the total risk that is acceptable for the 

most-exposed person must be less for each of the source categories to which the person is 

exposed.

According to the commenter, the EPA has full authority under section 112(f)(2) to 

address the full public health risk faced by the affected individuals and community before 

deciding what limit to set for this source category. The commenter explained that the EPA is 

required to decide whether to set a standard for a given source category if the cancer risk from 

that specific source category is 1-in-1 million or more, and if that source category’s emissions 

are between 1-in-1 million and the presumptive limit on acceptability (currently 100-in-1 

million); and if that source category is contributing risk along with numerous other source 

categories, then EPA has the authority under section 112(f)(2) to decide both that the total, 

cumulative risk is unacceptable, and that the specific risk contributed by the source category is 

unacceptable. The commenter cited the EPA’s explanation in the Coke Ovens Rule, where the 

EPA addressed and set a limit to account for increased community exposure at the final stage of 

its “ample margin of safety” determination.

Response: Based on Response from Wood Furniture. The EPA’s analysis did not ignore 

feasible assessments of cumulative risk. The EPA conducted an assessment of the cumulative 

cancer risks from emitted carcinogens and the cumulative noncancer hazard indices from all 

emitted non-carcinogens affecting the same target organ system for both the source category

emissions and the facility-wide emissions. This assessment excluded background contributions. 

While the incorporation of additional background concentrations from the environment in our 

 

70 See U.S. EPA’s Residual Risk Assessment for the Pulp & Paper Source Category, in the docket for the subpart S 

rulemaking.
57

risk assessments (including those from mobile sources and other industrial and area sources) 

could be technically challenging, they are neither mandated nor barred from our analysis. In 

developing the decision framework in the Benzene NESHAP currently used for making residual 

risk decisions, EPA rejected approaches that would have mandated consideration of background 

levels of pollution in assessing the acceptability of risk, concluding that “comparison of 

acceptable risk should not be associated with levels in polluted urban air‘‘ (54 FR 38044, 38061, 

September 14, 1989). Background levels of certain HAPs can be relatively high, perhaps even 

above a level that might be considered “safe.” Background levels (including natural background) 

are not barred from EPA‘s AMOS analysis, but EPA may consider them, as appropriate and as 

available, along with other factors, such as cost and technical feasibility, in the second step of its 

section 112(f) analysis. In this analysis, background levels were not considered because it is 

technically infeasible. This is because, for this source category, technical limitations in the data 

set for this source category make it insufficient to create a reliable analysis.

46. Comment: Commenter 0218 stated that, by focusing on cost, the EPA failed to set a 

residual risk standard that provided the requisite “ample margin of safety to protect public 

health,” pursuant to CAA section 112(f)(2). The commenter argued that the “ample margin”

determination assumes that EPA has already reduced risk to an “acceptable” level, and requires 

EPA to consider additional reductions to provide an “ample margin,” not just the bare minimum 

amount of protection for public health, including cancer and non-cancer risks. However, 

according to the commenter, the EPA’s “ample margin” analysis did not center on health 

protection but on cost.

The commenter noted that the EPA failed to consider or determine whether its proposed 

rule provided the maximum feasible protection against health risks for the greatest number of 

people, and that the EPA included no discussion or analysis regarding what the maximum 

feasible protection would be, or how many people could be protected from a greater level of risk.

The commenter asserted that, by setting the standard without finding or explaining how its 

proposal provided more than bare minimum protection for public health, the EPA rendered the 

phrase “ample margin of safety to protect public health” superfluous and violated section 

112(f)(2).

The commenter observed that the EPA’s proposal still exposed people to a cancer risk 

significantly higher than the 1-in-1 million target of section 112(f)(2), to acute health risk that is 

20 times the threshold (HQ of 30), and to both chronic and multipathway risks. The commenter 

asserted that the EPA had failed to justify this or explain why there is an “ample margin of 

safety” under its proposed rule.

The commenter stated that the uncertainty that has likely led the EPA to underestimate 

health risk in the first place requires a greater margin of protection at this final rulemaking stage. 

The commenter pointed to recent research providing new information on why risks from air 

pollution are likely to be undercontrolled and underestimated.

The commenter asked that the EPA consider what is needed, particularly cumulative 

impacts, to provide an “ample margin of safety” to protect the most exposed person from each 

type of health risk, as well as the cumulative burden, or combination of health risks–cancer, 

chronic non-cancer, acute, and multipathway. The commenter listed factors that should be 
58

considered in order to provide an “ample margin of safety”: cumulative impacts, facility-wide 

risk numbers, children’s health, multiple source exposure, and EJ factors.

The commenter stated that the EPA may not lawfully consider cost in deciding what is 

the “ample margin of safety to protect public health,” rather there is only an authorization to 

consider cost in determining whether additional standards are needed to prevent environmental 

harm. The commenter stated that, although the D.C. Circuit Court previously allowed the 

Agency to consider cost in the HON decision, that case was wrongly decided, and EPA should 

not rely on it as justification to evade the statute. The commenter noted that in section 112(f)(2), 

the clause “taking into consideration costs, energy, safety, and other relevant factors” only 

modifies the environmental effect prong of EPA’s duty, and does not apply to the health prong of 

the EPA’s statutory duty. The commenter further noted that the statement in section 112(f)(2)(B)

is not a clear statement authorizing the consideration of cost and it does not enshrine EPA’s prior 

Benzene rule analysis forever in all instances, rather the purpose of citing the Benzene Rule was 

not to enshrine that rule or its statutory interpretations for all time, but to prevent back-sliding by 

the agency after the 1990 Amendments. The commenter concluded that the statute prohibits the 

agency from considering cost in its “ample margin” analysis.

Response: Based on Response from Wood Furniture As stated in the Benzene NESHAP, 

in determining the need for residual risk standards in the risk acceptability determination, we 

strive to limit to no higher than approximately 1-in-10 thousand (100-in-1 million) the estimated 

risk that a person living near a plant would have if he or she were exposed to the maximum 

pollutant concentrations for 70 years and, in the ample margin of safety determination, to protect 

the greatest number of persons possible to an individual lifetime risk level of no higher than 

approximately 1-in-1 million. However, in determining whether to require additional standards, 

these levels are not considered rigid lines, and we weigh the cancer risk values with a series of 

other health measures and factors, including estimates of uncertainty, in both the risk 

acceptability and the ample margin of safety determinations. Relative to the commenter’s 

concerns about providing protection to the “greatest number of people,” we look closely at the 

populations impacted at greater than 1-in-1 million risk (see Chapter 3 and Table 3.2.1 of the 

final risk assessment document). If we determine that the risk is unacceptable, we must impose 

additional requirements to reduce emissions without consideration of cost. However, as part of 

our determination of whether standards protect public health with an ample margin of safety, we 

do not look solely at whether technology is feasible, (as urged by the commenter) but also 

consider cost, as statutorily required. Our consideration of cost under section 112(f) is consistent 

with the D.C. Circuit Court’s decision in the HON case. NRDC v. EPA, 529 F.3d 1077, 1083 

(D.C. Cir. 2008) (“As explained above, subsection 112(f)(2)(B) expressly incorporates EPA's 

interpretation of the Clean Air Act from the Benzene standard, complete with a citation to the 

Federal Register. In that rulemaking, EPA set its standard for benzene ‘at a level that provides 

‘an ample margin of safety’ in consideration of all health information ... as well as other relevant 

factors including costs and economic impacts, technological feasibility, and other factors 

relevant to each particular decision.’ 54 Fed.Reg. at 38,045 (emphasis added). EPA considered 

cost in Benzene, and subsection 112(f)(2)(B) makes clear that nothing in the amended version of 

the Clean Air Act shall ‘affect[ ]’ the agency's interpretation of the statute from that 

rulemaking.”) We are also required to consider cost as part of technology review under section 

112(d)(6), which we are required to perform periodically.
59

Regarding the consideration of cumulative impacts and facility-wide impacts, the 

development of facility-wide risk estimates provides additional information about the potential 

cumulative risks in the vicinity of the RTR sources, as one means of informing potential riskbased decisions about the RTR source category or categories in question. We agree with the 

commenter on the need for the need for their consideration in the assessment when it is possible.

Logically, the facility-wide assessment will provide the best estimate of cumulative HAP 

impacts, since it will include HAP impacts from other sources on the site when emissions data 

are available. In this circumstance, the data were available from our ICR and used in the 

assessment. Because these risk estimates were derived from facility-wide emissions estimates 

which have not generally been subjected to the same level of engineering review as the source 

category emission estimates, they may be less certain than our risk estimates for the source 

category in question. While we recognize that fact, these risk estimates remain important for 

providing context, as long as their uncertainty is taken into consideration in the process. Notably, 

for the RTR we are finalizing, our evaluation of facility-wide risk did not change our decisions 

about acceptability and ample margin of safety for this category.

47. Comment: Commenter 0218 stated that the EPA failed to provide a determination of the 

environmental effects from this source category and may not rationally or lawfully assume there 

is no potential for environmental effects based on the health assessment. The commenter

expressed concern that the EPA stated that there is “no potential for adverse environmental 

effect” from this source category and that the EPA based its environmental determination on its 

human health assessment. The commenter disagreed with the EPA’s level of assessment for 

environmental effects and, referencing court findings, stated that the residual risk review is the 

proper time for EPA to consider these effects, including the need to engage in Endangered 

Species Act (ESA) consultation under 16 U.S.C. 1536. However, the commenter noted that EPA 

has not even assessed whether there are any federally listed species with habitat near the 

facilities in this source category.

The commenter objected to the EPA’s use of health risk numbers, stating that these 

numbers are above the threshold and the EPA’s reference doses apply to rodents, but are not 

necessarily sufficient for protecting more sensitive wildlife or other environmental receptors. The 

commenter noted that the SAB has stated: “The assumption that ecological receptors will be 

protected if human health is protected is incorrect.” The commenter observed that risks include 

inhalation risk for wildlife and persistent or bioaccumulative chemicals in the environment. The 

commenter asked that the EPA perform an appropriate ecological assessment.

Response: We disagree with the commenter that we do not provide a rationale for this 

judgment. Section 2.5 of the risk assessment report71 states that:

Human health dose-response reference values are generally derived from studies 

conducted on laboratory animals (such as rodents) and developed with the inclusions of 

uncertainty factors that could be as high as 3000. As a result, these human reference 

values are often significantly lower than the level expected to cause an adverse effect in 

an exposed rodent. It should be noted that there is a scarcity of data on the direct 

 

71 See U.S. EPA’s Residual Risk Assessment for the Pulp & Paper Source Category, in the docket for the subpart S 

rulemaking.
60

atmospheric impact of these HAP on other receptors, such as plants, birds, and wildlife.

Thus, if the maximum inhalation hazard in an ecosystem is below the level of concern for 

humans (i.e., is below the human health reference value, which is itself a lower reference 

value than would be expected for an ecologic effect), we have generally concluded that 

mammalian receptors should be at no risk of adverse effects due to inhalation exposures 

from non PB-HAP, and have assurance that other ecological receptors are also not at any

significant risk from direct atmospheric impact.

With respect to the potential for ecological risk associated with PB-HAP, we note that 

our multipathway analysis indicated that all chronic non-cancer HQ values were less than 1,

using human health reference values. Thus, we believe that it is unlikely that adverse 

environmental effects would occur considering actual emissions of the HAPs in question.

With respect to the issue of ecological risk separate from risk that can be ascribed or 

compared to human impact risk and to endangered species findings...

48. Comment: Commenter 0171 applauded EPA’s recognition of the need for additional 

requirements due to advancements in control technologies. The commenter urged the Agency to 

consider others that may be identified during the rulemaking process as well. However, because 

of the adverse health effects associated with exposure to the substances emitted by pulp and 

paper facilities, the commenter was concerned about some of the risks that EPA has identified as 

remaining after the implementation of MACT and its decision to not reduce them. For example, 

EPA is not proposing to require additional measures to address an acute noncancer HQ of 20 

(where 1 is the threshold EPA considers acceptable). The commenter recommended that EPA 

reexamine these findings and take any necessary steps to ensure that the public is protected in 

accordance with the intent of the CAA.

Response: As noted above, the acute risk screen is a worst-case scenario. It assumes 

worst-case meteorology, peak emissions for all emission points occurring concurrently, and an 

individual being located at the site of maximum concentration for an hour. Considering these 

factors, the EPA does not believe that in all RTR reviews, HQ values must be less than or equal 

to 1 in order for source category risk to be considered acceptable. Rather, the EPA finds that 

acute risks must be judged on a case by case basis in the context of all the available health 

evidence and risk analyses, including the results of the chronic, non-cancer and cancer risk 

analyses. Only 9 facilities of the 174 modeled had an HQ > 1, with only 1 facility having an HQ 

> 10. An analysis of this site indicates that the HQ was actually 15, which was rounded to 20, 

and that there was no exceedance of an AEGL (HQ (AEGL-1) = 0.4). Also, the maximum 

exposure locations are located by the river along unpopulated forested areas. The location where 

people actually reside has a maximum HQ = 2. Based upon the conservative nature of the acute 

screen in conjunction with the chronic risks, EPA finds the risk to be acceptable for this source 

category. Additional information regarding the finding of acceptable risk can be found in section 

IV.B.1 of the preamble to the proposed rule (76 FR 81344). 

4.5 Demographics

49. Comment: Two commenters (0161 and 0171) supported EPA conducting demographic 

analysis used in this pulp and paper RTR for each individual facility, rather than using its prior 
61

approach of combined generic demographic analyses for EJ concerns. Commenter 0161.1 

supported EPA’s approach to review the impact of the proposed regulation on minority and lowincome populations. The commenter suggested the following changes to further improve the 

assessment: providing justification for the selection of the 1.25 threshold and ensuring that 

EPA’s Office of Environmental Justice participates in future evaluations of proposed rules.

Commenter 0171 specifically recommended that the rule writers work with EPA’s Office of 

Environmental Justice to develop criteria and specific guidance on how to interpret and apply the 

outcome of EJ analyses in the rulemaking process.

Response: To the extent that data are available, the Agency uses facility-specific 

information to supplement the national-scale analysis. This additional information provides a 

more complete picture of the community surrounding the largest-emitting sources and helps 

identify whether the low-income and minority populations that live near the sources in this 

source category are clustered around several facilities or are more equally distributed.

We agree with the commenter, and we do work closely with the EPA’s Office of 

Environmental Justice, as well as other offices across the Agency, to develop criteria and specific 

guidance on how to interpret and apply the outcome of these types of analyses in the rulemaking 

process. To ensure that our actions comport with our statutory authorities and requirements, we 

work with our Office of General Counsel (OGC) and Office of Enforcement and Compliance 

Assurance (OECA).

50. Comment: Commenter 0218 stated that the socioeconomic disparity in health risk from 

the pulp and paper source category makes the risk the EPA has found unacceptable, and the EPA 

must finalize a rule that is consistent with the principle of EJ. The commenter asserts that the 

EPA’s analysis has not fully assessed EJ impacts.

Commenter 0218 proposed that the EPA take action to provide EJ because it has found 

disproportionate impacts based on race, because the African-American community is overrepresented in the category of people exposed to higher risk from this source category, compared 

to its national population. Since the risk from the pulp and paper source category has 

disproportionate effects in these communities, the commenter suggested additional monitoring

and stronger enforcement provisions to prevent emission spikes, malfunctions. and other 

violations would help provide EJ.

The commenter stated that the EPA did not complete a full EJ analysis for this source 

category and should do so now to ensure that it appropriately assesses the risk to public health 

under section 112(f)(2) and satisfies the obligations under EO 12898, as well as EPA’s own 

policy commitment to consider EJ in rulemaking.

After providing suggestions for improvements to the EPA’s EJ assessment, the 

commenter recommended that the EPA also fully incorporate the improved EJ assessment into 

the policy decision it chooses in the final rule, by recognizing that it is not fair or acceptable for 

particular individuals or communities to have this type of disproportionate impact.

Response: Under EO 12898, EPA is directed to the greatest extent practicable and 

permitted by law, to make EJ part of their mission by identifying and addressing, as appropriate, 
62

disproportionately high and adverse human health or environmental effects of their programs, 

policies and activities on minority populations and low-income populations in the United States. 

Consistent with EO 12898 and the Presidential Memorandum that accompanies it, the EPA’s EJ 

policies promote EJ by focusing attention and Agency efforts on addressing the types of 

environmental harms and risks that are prevalent among minority, low-income and indigenous 

populations. EO 12898 and the Agency’s EJ policies do not mandate particular outcomes from 

an action, but they demand that decisions involving the action be informed by a consideration of 

EJ issues. 

With respect to this rule, the EPA found the overall level of risk from the pulp and paper

source category to be acceptable and to provide an ample margin of safety for all populations in 

close proximity to these sources, including minority and low-income populations. Consequently, 

EPA did no further tightening of the standard. However, EPA is requiring 5-year repeat testing 

and eliminating the SSM exemption to ensure continuous compliance with the standards. 

Furthermore, repeat testing will provide incentive for facilities to maintain their control systems 

and make periodic adjustments to ensure peak performance, thereby reducing emissions and the 

potential for periodic episodes of acute risk. Eliminating the SSM exemption will provide an 

incentive for facilities to minimize emissions during periods of SSM. By eliminating SSM 

exemptions and limiting the affirmative defense provisions to only malfunctions that result in a 

violation to a standard and cannot be connected to poor maintenance or mismanagement, poor 

work practices that may have previously remained undetected should be apparent to those 

responsible for oversight and implementation. Additionally, both the monitoring and reporting 

sections of the rule have been strengthened through the use of the Electronic Reporting Tool 

(ERT) and the Compliance Emission Data Reporting Interface (CEDRI). Both ERT and CEDRI

will provide the public with contemporary, easily searchable electronic information about 

performance testing in a public database.

51. Comment: Two commenters (0218 and 0171) appreciated that the EPA recognized the 

need to look at population data, including on the socioeconomic impact, in order to consider the 

actual people affected by pollution from the pulp and paper source category, to assess the 

community impacts in context, and to consider EJ as part of this rulemaking. One commenter 

(0218) stated that, in addition to looking at the demographic census data, the EPA must assess 

the starting point or baseline “overall health” status of the affected individuals and communities,

using the best available data at a local and national level, including the baseline cancer levels.

The commenter suggested that the EPA should follow the recommendations of its own interim

guidance and include in its analysis an assessment of the percent of the population with limited 

English proficiency, infant mortality, and low birth-weight births.

Two commenters (0218 and 0171) supported the EPA’s decision to assess the 

demographics within 5 kilometers (or 3 miles) of affected sources. One commenter (0218) 

suggested that the EPA should also evaluate impact within a broader area, where it has 

information that there is potential for dispersion beyond the 3-mile radius. Three commenters 

(0161.1, 0218, and 0171) asked that the poverty statistics be updated to include 2010 census 
63

data, rather than relying on older information. The number of people in poverty in 2010 is the 

largest number in the 52 years for which poverty estimates have been published.72

Response: As noted in the response to comments above, per the EPA’s interim guidance 

on EJ and the Action Development Process, the Agency is encouraging rule writers and policy

makers to look at the whole range of factors that impact communities and population groups 

when crafting rules. In regards to how the Agency conducts its analysis, the EPA is continuing to 

discuss and pilot approaches that are consistent with the Agency’s responsibilities regarding EJ 

as outlined in EO 12898. In determining the need for residual risk, the EPA strives to limit to no 

higher than 1 in 10 thousand (100 in 1 million) the estimated cancer risk for persons living near a 

plant if exposure to the maximum pollutant concentration for 70 years and to protect the greatest 

number of persons to a individual lifetime risk of no higher than 1 in 1 million. Considerations 

are made for all people regardless of racial or socioeconomic status. In response to the comment 

on the need to assess impacts beyond a 3-mile radius, the EPA agrees that it is helpful sometimes 

to analyze a larger potential impact area. The EPA typically uses a radius of 50 kilometers (31 

miles) for the purpose of residual risk analyses.

52. Comment: Commenter 0218 asked that, as part of providing sufficient information to 

affected local communities, the EPA should publish a plain-language statement of the health 

risks and benefits from EPA’s final action, and in future rule proposals. The commenter stated

that, although it provides the MIR and chronic and risk numbers, these are not easily

understandable by the general public. The commenter asked for expanded discussion of health 

disorders or other adverse effects, stating that, without a full discussion of health impacts and 

risks, it is difficult for the public to provide meaningful comment on the impact this proposal will 

have on their lives, which is an EJ issue.

The commenter also asked that the EPA provide a statement and analysis in this residual 

risk rulemaking (and all others) on the real world impacts of EPA’s rulemaking, so that the 

public has a clear understanding of what the risk is, and precisely what types of harm to public 

health EPA is determining are “acceptable” and “unacceptable.” The commenter believes that 

this is needed to inform EPA’s and the public’s consideration of what level of risk is acceptable 

or unacceptable, and what standard is required to provide an ample margin of safety.

Response: The EPA agrees that providing sufficient information is important, so affected 

communities have a meaningful opportunity to participate in EPA rulemakings. It is the EPA’s 

goal to use plain language in all rule preambles and risk assessments so that they are 

understandable to the general public. As future preambles, fact sheets, and assessments are 

written, we welcome input on how the health discussion should be expanded and how the risk 

numbers and critical concepts like “ample margin of safety” can be set in a context that is easier 

to understand.

For this rule, there is additional health information contained in the docket,

73 and EPA 

has provided the contact information (in the rule preamble) for the technical experts who can be 

contacted for assistance in understanding this rule and the risk modeling that was conducted.

 

72 U.S. Census 2011. Income, Poverty, and Health Insurance Coverage in the United States: 2010. Available online 

at: http://www.census.gov/prod/2011pubs/p60-239.pdf.
64

53. Comment: Two commenters (0162 and 0196) objected to EPA’s accounting for EJ in 

developing the proposed rule, i.e., whether “there is an overrepresentation of minority, low 

income, or indigenous populations near the sources such that they may face disproportionate 

exposure from pollutants that could be mitigated by this rulemaking” (76 FR 81353). The 

commenters noted EPA’s conclusion that the rule will not have such effects because “it increases 

the level of environmental protection for all affected populations without having any 

disproportionately high and adverse human health or environmental effects on any population, 

including any minority, low income, or indigenous populations.” However, the commenters

argued that EPA is without authority to factor such EJ considerations into this rule, because the 

term “public health” cannot reasonably be interpreted to include consideration of EJ in the 

context of section 112(f). According to the commenters, section 112(f)(2)(A) expressly instructs 

EPA to impose additional emissions controls if needed to provide an ample margin of safety “to 

protect public health.” The commenters noted that the term “public health” is not defined in 

section 112 or in EPA’s Part 63 regulations.

The commenters (0162 and 0196) noted that, for EPA’s NAAQS program, the Supreme 

Court has observed that the “primary definition of the term” should be applied, i.e., that public 

health means “the health of the public.” Whitman v. American Trucking Associations, Inc., 531 

U.S. 457, 465 (2001). According to the commenters, this conclusion emphasized that the scope 

of the term “public health” should be dictated by the meaning of the word “public.” To illustrate, 

the commenters cited Webster’s Dictionary, which defines the adjective “public” to mean “of, 

relating to, or affecting all of the people or the whole area of a nation or state” and “of or relating 

to people in general.” The commenters pointed out that these definitions emphasize that the word 

“public” should be construed expansively as describing the people as a whole, and not particular 

demographic segments.

The commenters asserted that EPA’s established approach to assessing potential impacts 

on public health under the NAAQS program is consistent with this meaning. According to the 

commenters, EPA reasonably interprets the term “public health” to include consideration not 

only of potential impacts to the population as a whole, but also to sensitive subpopulations –

recognizing that the objective is to protect the group rather than any particular individual in the 

group (e.g., 71 FR 61144, 61145 fn. 2 (Oct. 17, 2006)). The commenters noted that sensitive 

subpopulations are identified according to their particular health-based sensitivities (e.g., 

asthmatics) rather than demographic classifications unrelated to particular health-based 

sensitivities (e.g., population without a high school diploma).

The commenters further argued that, with this backdrop, it would not be reasonable to 

construe the term “public health” as used in section 112(f) as allowing consideration of 

demographic classifications that bear no relationship to the potential health effects presented by 

the HAPs at issue for the given source category or subcategory. According to the commenters, 

EPA’s proposal would unreasonably inject racial, ethnic, economic, and other policy

considerations into a program designed to provide protection for the public at large. To illustrate, 

the commenters stated that, if EPA were to suggest that the population without a high school 

diploma should receive extra scrutiny, it raises the question why EPA should not afford the same 

 

73 See U.S. EPA’s Residual Risk Assessment for the Pulp & Paper Source Category among other RTR-related 

documents, in the docket for the subpart S rulemaking.
65

scrutiny to other reasonably definable educational groups, such as those with a high school 

diploma, those with college degrees, and those with advanced degrees. According to the 

commenters, there is simply no principled way to identify and define those groups that should 

receive extra scrutiny from those that do not. To conclude, the commenters argued that injecting 

EJ considerations into section 112(f) standard setting would inappropriately cause arbitrary

policy and political considerations to trump objective scientific analysis, which would be 

patently unreasonable and, as such, would not be a supportable interpretation of section 112(f).

Response: As described above, the Agency is directed by EO 12898 to make EJ part of 

our mission. The EPA disagrees that the term “public health” cannot include consideration of EJ. 

The EPA defines EJ to mean fair treatment and meaningful involvement of all people, and this 

definition represents a commitment to ensuring that EPA works to improve conditions affecting 

the public health of all Americans so that everyone has access to clean water, clean air and 

healthy communities. 

As stated in the Benzene NESHAP, in determining the need for residual risk standards, 

we strive to limit to no higher than approximately 1-in-10 thousand (100 in a million) the 

estimated cancer risk that a person living near a plant would have if he or she were exposed to 

the maximum pollutant concentrations for 70 years and, in the ample margin of safety decision, 

to protect the greatest number of persons possible to an individual lifetime risk level of no higher 

than approximately 1-in-1 million. These considerations are made for all people, regardless of 

racial or socioeconomic status. However, in determining whether to require additional standards 

under section 112(f), these levels are not considered rigid lines, and we weigh the cancer risk 

values with a series of other health measures and factors in both the decision regarding risk 

acceptability and in the ample margin of safety determination. We also consider cost of controls 

in the ample margin of safety determination. While we analyzed the demographic makeup of the 

at-risk populations surrounding the facilities within the source category addressed by this 

rulemaking, we ultimately concluded that the risks were acceptable for all population groups and 

protected public health with an ample margin of safety. Thus, while the results of our 

demographic analyses served to provide information about the demographic makeup of the 

populations exposed to the source category, the EPA did not base its decision solely on these 

analyses.
66

5. Technology Review

54. Comment: Commenter 0218 stated that the EPA did not consider the full range of 

control options available and arbitrarily relied on unsupported assumptions for the options it did 

consider. The commenter stated that the EPA’s analysis of available controls failed to include

practices, processes and technologies that have achieved greater emission reductions and 

dismissed options with little or no analysis or support. The commenter recommended that the 

EPA should have researched vendor literature and discussed options with vendors regarding 

newer technologies and improvements to old technologies that make them more cost-effective 

and efficient, and could have consulted with the pollution control technology industry, including 

the Institute of Clean Air Companies (ICAC), and other national, state and local jurisdictions‘ air 

pollution control agencies.

The commenter stated that EPA’s standards do not reflect the actual emission levels 

achieved by the relevant best performers. The commenter recommended that the EPA set revised 

standards that meet the test under section 112(d)(2) and (d)(3), by setting a MACT floor that 

does reflect the emission levels achieved by the relevant best performers (those with the lowest 

emissions) and beyond-the-floor standards reflecting the maximum achievable degree of 

reduction in each of the hazardous air pollutants that the category emits.

Response: As promulgated, the pulp and paper MACT (subpart S) standards include 

emissions standards for pulping system vents, kraft pulping process condensates, and bleaching 

system vents. The commenter is incorrect in their statement that the full range of controls was

not considered in the technology review of subpart S. Contrary to the consultations which the 

commentator suggests we avoided, EPA performed a thorough evaluation of new pollution 

control technology by analyzing nearly 100 entries in the Reasonable Available Control 

Technology/Best Available Control Technology/Lowest Achievable Emission Rate 

(RACT/BACT/LAER) Clearinghouse (RBLC) database74 for pulp and paper sources and 

reviewed the European Commission’s December 2010 reference document75 on the best 

available control techniques in the pulp and paper industry. We also conducted a thorough 

review of control technology information from the 2011 Part I survey responses, which would be 

expected to include information on the same practices, processes, and technologies that pollution 

control vendors and state and local air pollution control agencies would have provided. 

Consequently, we contend that we have met the CAA section 112 (d)(6) requirement to review 

the latest practices, processes and control technologies being used and available for use in 

subpart S sources.

Notwithstanding the fact that we did not identify any new technologies in our review, the 

commenter indicates that had we identified new technologies, we would have been obligated to 

conduct another section 112(d)(2) and (d)(3) MACT floor setting exercise. As we have noted 

previously, we do not believe that we are obligated to do a section 112(d)(2) and (d)(3) analysis 

 

74 See memorandum from T. Holloway and C. Gooden, RTI, to J. Bradfield and B. Schrock, EPA, titled Summary of 

RBLC and Other Findings to Support Section 112(d)(6) Technology Review for Pulp and Paper NESHAP, 

September 30, 2011, in the docket for the subpart S rulemaking.

75 See European Commission document, titled Integrated Pollution Prevention and Control (IPPC): Reference 

Document on Best Available Techniques in the Pulp and Paper Industry, Draft April 2010.
67

under a section 112(d)(6) technology review requiring a reanalysis or recalculation of MACT 

floors. See proposed National Emission Standards for Coke Oven Batteries (69 FR 48388, 48351 

(August 9, 2004)). Instead, we interpret section 112(d)(6) as essentially requiring us to consider 

developments in pollution control in the industry (‘‘taking into account developments in 

practices, processes, and control technologies’’), and assessing the costs of potentially stricter 

standards reflecting those developments. We read this provision as providing the EPA with 

substantial latitude in weighing these factors and arriving at an appropriate balance in 

considering revisions to our standards. This discretion also provides us with substantial 

flexibility in choosing how to apply modified standards, if necessary, to the affected industry.

55. Comment: Commenter 0218 asserted that near-zero air-discharge pulp and paper 

facilities exist and are common in Europe. (The commenter cited two European Commission 

reference documents on best available techniques in the pulp and paper industry.) The 

commenter mentioned a process that uses modified cooking plus oxygen delignification, and 

uses only ozone and peroxide to bleach, which results in zero discharge of chlorine dioxide 

(ClO2) and chlorinated organic substances measured as adsorbable organic halides (AOX). The 

commenter argued that, while EPA notes that some facilities in the U.S. use totally chlorine free 

(TCF) processes, it fails to rationally explain why TCF processes were not considered the MACT 

floor for pulp and paper facilities. Further, the commenter stated, the technology is now mature, 

with 25 percent of the European paper supply made of TCF paper, and represents the least toxic 

alternative, and the European Union (EU) requires near-zero discharge processes–ECF bleaching 

with low AOX, or TCF bleaching – as Best Available Technology. The commenter stated that 

the EPA’s failure to require modified cooking, oxygen delignification, and ozone and peroxide 

bleaching is arbitrary and capricious under section 112(d)(6).

Response: The European Commission reports that ozone and peroxide bleaching can be 

used when modified cooking and oxygen delignification are used as bleaching pretreatments, and 

these processing steps result in zero discharge of Cl2 and AOX compounds. The Commission 

does not, however, report the wood species and type used in this process or either the source or 

the end use of the pulp made with this process. When virgin fiber is pulped, lignin content 

(chemical structure and amount) varies significantly based on wood type and species, and the 

aforementioned process is not applicable to all species of wood. The ozone and peroxide

bleaching processes are lignin-chemical-structure-specific and do not react with all structures

and result in a final product with lower brightness. The process would be appropriate if the final 

product was toilet paper, but would not be appropriate for printing and writing grades. These 

grades require complete lignin removal. When recycled bleached fiber is pulped, lignin has

typically already been removed, and ozone/peroxide bleaching should be sufficient to brighten a 

recycled pulp—a pulp that was initially bleached with chlorinated compounds. Extended cooking 

and oxygen delignification would be required for virgin fibers that undergo an ozone- and 

peroxide-only bleaching process, which would result in lower pulp yields and, thus, higher raw 

material costs. It would also generate higher amounts of black liquor solids that require 

processing in the recovery furnace. In older facilities such as those in the U.S. (as compared to 

the newer ones in Europe), recovery furnaces are commonly running at capacity and could not 

support the burning of additional solids. Where capacity is available, burning higher amounts of

black liquor solids would result in additional negative secondary emission impacts (higher 

carbon monoxide [CO], nitrogen oxides [NOX], sulfur dioxide [SO2], and particulate matter 

[PM]) subsequent to such a change in bleaching technology.
68

The EPA investigated the use of TCF and ECF processing during the technology review. 

In the same document to which the commenter refers, the European Commission reports that 

effluent from the TCF process is not significantly different from the ECF process, and it notes 

that the use of a TCF process requires the removal of metals in pulps using chelation, which 

results in the use of non-biodegradable, potentially hazardous metal compounds that must be 

landfilled. The TCF processes currently used in the U.S. are used with secondary or mechanical 

pulps, not virgin kraft pulps. The tree species used to produce virgin kraft pulp in the U.S. do not 

efficiently respond to ozone and peroxide bleaching without the use of ClO2 to reach consumerrequired final product brightnesses.

Oxygen Delignification (O2Delig) is encouraged by the current subpart S standards 

because bleaching requirements are reduced through the use of O2Delig and, therefore, the 

pollution control requirements (99+ percent control) and costs are reduced. The costs for 

O2Delig were given extensive “beyond the floor” attention in the evaluations for the original 

cluster rule, which combined the subpart S MACT rules with new pulp and paper effluent 

guidelines under the Clean Water Act (CWA). Specifically, O2Delig was evaluated because of 

its positive impact on wastewater treatment requirements. However, the beyond-the-floor 

evaluation did not justify requiring O2Delig as part of the Cluster Rule. We are only conducting 

a review of the subpart S MACT (air) rule promulgated under Cluster Rule, so a new O2Delig 

analysis was not deemed appropriate. Similarly, TCF was evaluated under the Cluster Rule for 

its positive impact on wastewater treatment and as a beyond the floor technology, but was not 

found to be justified. As with O2Delig, we set up the standards in the original rule to encourage 

TCF bleaching through the use of targeted exemptions, which remain in place following this 

technology review. AOX was only addressed in the water rules promulgated under the Cluster 

Rule and was reduced through the use of limitations on chlorinated bleaching, which also remain 

in place following our review of the bleaching system MACT requirements.

76,77

As the commenter stated, only about 25 percent of the European paper supply is made of 

TCF paper, showing that the processing is not applicable to all papermaking processes. The 

statement that the EU requires near zero-discharge processes is not relevant to this action, as 

subpart S is an air rule, not a water rule. The U.S. required that the industry convert from Cl2

bleaching to ECF or TCF bleaching with the original Cluster Rule, and the explanation as to why

EPA did not require modified cooking, O2Delig, and ozone and peroxide was discussed in the 

original subpart S rule (63 FR 18504) and is not applicable to many processes in the U.S. 

Therefore, the purported “failure to require modified cooking, oxygen delignification, and ozone 

and peroxide bleaching” (according to the commenter) is not supported by the record and should 

not be considered arbitrary and capricious under section 112(d)(6).

5.1 EPA’s Authority under CAA Section 112(d)(6)

56. Comment: Commenter 0218 stated that section 112(d)(6) serves as an on-going ratchet 

to continually require the EPA to update standards to keep pace with new technology in order to 

 

76 See memorandum from K. Spence and J. Bradfield, EPA, to Docket EPA-HQ-OAR-2007-0544, titled Summary of 

Pulp Bleaching Technology Review, November 22, 2011, in the docket for the subpart S rulemaking.

77 See Pulp, Paper and Paperboard Industry – Background Information for Promulgated Air Emission Standards 

Final EIS; EPA-453/R-93-050b.
69

decrease emissions. The commenter observed that section 112(d)(6) requires EPA to revise its 

MACT “floor” in accordance with section 112(d)(2)-(3) and (6), to ensure that the standards 

continue to satisfy the requirements of section 112(d)(2)-(3), particularly where there are 

“developments” in technology, practices, and processes demonstrating that greater emissions 

reductions are “achievable” and sources have achieved significantly lower level of emissions “in 

practice” than the current MACT standards. The commenter found the EPA’s narrow reading of 

the term “developments” as unlawful and arbitrary. The commenter asserted that EPA failed to 

conduct a comprehensive evaluation of advances in control technologies, practices, and 

processes that may have achieved greater emission reductions than at the time of the original 

standards. The commenter recommended that the EPA look to jurisdictions with the most 

stringent standards for HAP emissions to gather data from facilities and information about 

control systems that are attaining the highest control efficiencies, because these stronger 

standards and permit limits for a similar source category are evidence that lower emission levels 

are being achieved and can be achieved, and are thus “developments” that EPA must consider 

under section 112(d)(6).

The commenter stated that control technology is only one factor in determining emissions 

levels of the best performing similar sources, according to the commenter, and other factors, 

such as fuel inputs and raw materials, must also be part of the best performing similar source 

determination. The commenter asserted that, for the pulp and paper source category, significant 

evidence demonstrates that, due to improvements in technology, many sources have “achieved” a 

level of “actual” HAP emissions that is not only below the existing MACT standard, but also 

below the standards proposed by EPA in the new rule.

According to the commenter, EPA itself notes that―[f]acilities’ actual emissions may

also be significantly lower than MACT-allowable emissions for other reasons such as state 

requirements, better performance of control devices or reduced production.

78 The EPA’s analysis 

of its emissions inventory for pulp and paper facilities indicates that the amount of emissions that 

are “allowable” under the existing MACT standard exceed estimated (what EPA calls “actual”) 

emissions and may be almost three times the “actual” emissions.79 In particular, the reported 

average actual performance level for percent reduction in kraft pulping process condensates is 

95 percent–fully 1 percentage point higher than EPA‘s proposed revised standard of 94 percent.

The EPA itself concluded that “there were mills performing better than the 92 percent minimum 

and that the great majorities [sic] were performing significantly better.”

80

The commenter concluded that, under section 112(d)(6), EPA must revise the existing 

MACT based on these developments and meet the requirements of section 112(d)(2)-(3), by 

setting standards more stringent than what EPA has proposed in this rulemaking; otherwise, the 

commenter asserted that EPA’s CAA section 112(d)(6) review of the existing section 112(d) 

standards was unlawful and incomplete.

 

78 See 76 FR 81,328, 81,334 (emphasis added).

79 See memorandum from T. Holloway, K. Hanks, C. Gooden, and M. Hakos, RTI, to J. Bradfield and B. Schrock, 

EPA, titled Inputs to the Pulp and Paper Industry October 2011 Residual Risk Modeling, Table 6B, November 11, 

2011, in the docket for the subpart S rulemaking.

80 See memorandum from J. Bradfield and K. Spence, EPA, to Docket EPA-HQ-OAR-2007-0544, titled Summary of 

Clean Condensate Alternative Technology Review, October 23, 2011, in the docket for the subpart S rulemaking.
70

Response: The commenter is mistaken on several grounds. First, the commenter asserted

that “the EPA recognizes that certain sources have ‘achieved’ a level of ‘actual’ emissions that is 

below the level allowed under the existing MACT standards” and cited the proposed rule 

preamble at 76 FR 81334. This was a qualitative, introductory statement about how NEI and 

other sources of data typically contain estimates of actual emissions that are “often” lower than 

allowable emissions. The statement was not specific to pulp and paper facilities or data and, in 

any event, did not contain any quantitative determination about actual emissions levels. 

Second, the commenter asserted that the EPA must use information suggesting that 

sources are operating at less than allowable emissions under CAA section 112(d)(6) to revise 

MACT standards, including recalculating MACT floors under section 112(d)(2)-(3). The 

commenter apparently is referring to the MACT allowable-to-actual emissions ratio developed 

for this rulemaking. The commenter is incorrect in characterizing this ratio as a determination of 

the level of actual emissions achieved in practice for the source category. The actual-toallowable ratio represents the lowest amount of HAP compared to the maximum allowed under 

the MACT. The allowable ratio is used for providing a worst-case scenario for estimating 

allowable emissions from the source, considering the compliance margin used by sources to 

account for variability in emission.

Third, the commenter is incorrect in asserting that the EPA must recalculate MACT 

floors under CAA section 112(d)(2)-(3). As explained in prior RTR rulemakings, the EPA does 

not read section 112(d)(6) as requiring a reanalysis or recalculation of MACT floors. See 

proposed National Emission Standards for Coke Oven Batteries (69 FR 48388, 48351 (August 9, 

2004)). Instead, we interpret section 112(d)(6) as essentially requiring us to consider 

developments in pollution control in the industry (“taking into account developments in 

practices, processes, and control technologies”), and assessing the costs of potentially stricter 

standards reflecting those developments. We read this provision as providing the EPA with 

substantial latitude in weighing these factors and arriving at an appropriate balance in 

considering revisions to our standards. This discretion also provides us with substantial 

flexibility in choosing how to apply modified standards, if necessary, to the affected industry.

For this rulemaking, an ICR was used to obtain much of the information used in EPA’s 

technology review. (We also reviewed nearly 100 entries in the RBLC database81 for pulp and 

paper sources and reviewed the European Commission’s December 2010 reference document82

on the best available control techniques in the pulp and paper industry.) Our review was not 

limited to applicable control technologies. The EPA reviewed other potential developments in 

practices, processes, and control technologies for the pulp and paper source category and 

evaluated costs of potentially more stringent standards reflecting any such developments. The 

EPA believes this review and the revisions finalized in this rulemaking satisfy the EPA’s 

obligations under CAA section 112(d)(6) for the pulp and paper source category.

 

81 See memorandum from T. Holloway and C. Gooden, RTI, to J. Bradfield and B. Schrock, EPA titled, Summary of 

RBLC and Other Findings to Support Section 112(d)(6) Technology Review for Pulp and Paper NESHAP,

September 30, 2011, in the docket for the subpart S rulemaking.

82 See European Commission document, titled Integrated Pollution Prevention and Control (IPPC): Reference 

Document on Best Available Techniques in the Pulp and Paper Industry, Draft April 2010.
71

57. Comment: Commenter 0172 did not believe that EPA had the legal authority to revise 

the condensate destruction standards in §63.446(e)(3), (e)(4) and (e)(5). As described by the 

American Forest and Paper Association (AF&PA) in their comment on the proposed rule, there 

have been no “developments in practices, processes and control technologies” that would justify

a revision of these standards.

Response: We disagree with the commenter’s interpretation of our legal authority. As 

noted above, we interpret section 112(d)(6) as requiring us to consider all developments in 

practices, processes, and control technologies in the industry. When we take into account the 

“developments in practices, processes, and control technologies,” we interpret that language as 

providing for EPA to not only to evaluate new control technologies and process improvements 

but also to evaluate the application of the control technologies that were the basis for the current 

MACT floor. In that evaluation we examine whether, in the ‘practice’ of applying the MACT 

standard technology, there have been technological advances. Generally, we consider whether 

the MACT floor technology, in practice, is performing better than anticipated in the original 

MACT floor analysis. Indeed, we did not find in our evaluation of data received in the ICR 

conducted prior to proposal that there were significant modifications to the basic kraft pulping 

process or new technologies for control of condensates. In the proposal, our initial evaluation 

indicated that kraft condensate control, using the technologies originally anticipated had 

improved since promulgation based on the information showing emissions control higher than 

the 92 percent standard. Consequently, we proposed to raise the treatment standard from a 92

percent control basis to a 94 percent basis.

83

In the final rule, however, we are not increasing the treatments standard, for the reasons 

discussed in the final rule preamble, in a memo prepared for promulgation,

84 and elsewhere in 

this response-to-comments document.

5.2 Chemical Pulping Standards

58. Comment: Commenters 0162 and 0163 agreed with EPA’s determination that “there 

have been no advances in emission control measures [for chemical pulping] since the subpart S 

standard was originally promulgated in 1998” (76 FR 81344). According to commenter 0162, the 

technology currently used by the industry for subpart S compliance is the same as when the rule 

was promulgated. Commenter 0162 stated that these systems have the same capabilities as the 

units that were used by the “best performing” mills that were the basis for the MACT “floor.”

Response: We acknowledge the commenters’ support for our conclusion that there have 

been no advances in emission control measures for chemical pulping vents since the subpart S 

standard was originally promulgated. This conclusion was based on our review of the 2011 Part I 

survey responses from the pulp and paper industry, information on pulp and paper control 

 

83 See memorandum from J. Bradfield and K. Spence, EPA, to Docket EPA-HQ-OAR-2007-0544, titled Summary of 

Kraft Condensate Control Technology Review, October 23, 2011, in the docket for the subpart S rulemaking.

84 See memorandum from C. Gooden, K. Hanks and T. Holloway, to J. Bradfield and B. Schrock, titled Costs, 

Environmental, and Energy Impacts for the Promulgated Subpart S Risk and Technology Review, May 11, 2012, in 

the docket for the subpart S rulemaking.
72

techniques in the RBLC, and the EU document on best available techniques in the pulp and 

paper industry.

85

59. Comment: Commenter 0218 declared that the EPA did not consider the full range of 

control options available for kraft pulping. The commenter pointed to evidence in the record 

(Summary of Clean Condensate Alternative Technology Review (EPA-HQ-OAR-2007-0544-

0129)) as demonstrating that greater reductions of HAPs from the kraft process could be 

achieved by using clean condensate limits, and that using fresh steam in the chip bin of a 

continuous digester could reduce emissions. The commenter stated that the EPA had failed to 

consider the development of these techniques since its last MACT rulemaking and had failed to 

show that its standards reflect the actual emission levels achieved by the best performers under 

section 112(d)(3). The commenter concluded that the EPA must set stronger standards.

Response: The clean condensate alternative (CCA) was implemented to encourage 

greater reductions at lower regulatory cost than the HVLC control required under MACT. Mill 

processes and thus HVLC emissions are site-specific. One technology identified in a CCA plan, 

(e.g., flash steam used in a chip bin) may be appropriate in one location, but is not necessarily 

available in all facilities. Generally, our analyses of CCA facilities indicated that the majority

implemented unique options available to their specific location. Steam generation is an energyintensive activity. A previous study has shown that a facility needs to generate 5,000 lb/hr of 

fresh steam (generally through the burning of fossil fuels) for chip bin pre-steaming, at an annual 

cost of $184,000.

86 The use of flash steam (generated from recovered process heat) in the chip 

bin reduces the need to produce fresh steam and the need to treat the gases. No new fresh steam 

is created, and the consequent boiler-generated HAP are avoided, and CCA credits can be 

generated. The EPA has also received comments indicating that heat balances are critical 

concerns in pulping operations but vary from mill to mill. Directing the use of steam was not 

considered to be an appropriate evaluation under this technology review since steam/energy

balances are particularly mill-specific.

87 This requirement would also not be appropriate for the 

current standard, as the standard refers to all kraft pulping standards, which include batch and 

continuous operations. Batch operations generally do not use pre-steaming in the chip bin.

5.3 Bleaching Standards

60. Comment: Commenters 0162 and 0163 agreed with EPA’s determination that “there 

have been no advances in emission control measures [for bleaching] since the subpart S standard 

was originally promulgated in 1998” (76 FR 81344). According to commenter 0162, the 

technology currently used by the industry for subpart S compliance is the same as when the rule 

 

85 Additional details on our technology review are provided in docket memoranda, titled Section 112(d)(6) 

Technology Review for Pulping and Papermaking Processes and Summary of RBLC and Other Findings to Support 

Section 112(d)(6) Technology Review for Pulp and Paper NESHAP and the European Commission document, titled

Integrated Pollution Prevention and Control (IPPC): Reference Document on Best Available Techniques in the Pulp 

and Paper Industry.

86 See Rosemount, Inc., “Chip Bin Level Measurement Nets Savings Over $2.3 Million,” 2008, available online at: 

http://www2.emersonprocess.com/siteadmincenter/PM%20Rosemount%20Documents/00830-1300-4024.pdf.

87 See memorandum from J. Bradfield and K. Spence, EPA, to Docket EPA-HQ-OAR-2007-0544, titled Summary of 

Clean Condensate Alternative Technology Review, October 23, 2011, in the docket for the subpart S rulemaking
73

was promulgated. Commenter 0162 stated that these systems have the same capabilities as the 

units that were used by the “best performing” mills that were the basis for the MACT “floor.”

Response: We acknowledge the commenters’ support for our conclusion that there have 

been no advances in emission control measures for bleaching since the subpart S standard was 

originally promulgated. This conclusion was based on our review of the 2011 Part I survey

responses from the pulp and paper industry, information on pulp and paper control techniques in 

the RBLC, and the EU document on best available techniques in the pulp and paper industry.

88

61. Comment: Commenter 0218 stated that EPA did not consider the full range of control 

options available for pulp bleaching. The commenter noted that EPA‘s technology review 

reveals that EPA identified two facilities with BACT emission limitations requiring bleaching 

using no Cl2 or ClO2, or bleaching with only hydrogen peroxide, sodium hydrosulfite, and 

sodium borohydride.89 According to the commenter, EPA flatly concluded, however, that the 

bleach plant chlorinated vent gas emissions are effectively controlled (99 percent), and that no 

amendment to current regulations is necessary despite EPA’s conclusion that emissions from the 

bleaching process exceed 5 million lbs of toxic air pollution each year.90

The commenter stated that EPA did not consider use of environmental management 

systems (EMS) or best practices and benchmarking to minimize pollution. The commenter noted 

that the EU recognizes that “the best environmental performance is usually achieved by the 

installation of the best technology and its operation in the most effective and efficient manner.”91

As part of the continuous improvement mechanism embodied by EMS, sources could be required 

regularly to review all chemicals used in the pulp and paper processes. Replacement chemicals 

that are safer for the environment should be used if possible, and necessary chemicals that cannot 

be replaced with safer alternatives should be used in the lowest amounts practical. This process is 

considered a Best Available Technique to reduce pollution in Europe, and should be included in 

the MACT floor in the United States.

According to the commenter, many pulp and paper facilities in the United States already 

use continuous improvement mechanisms such as best practices and benchmarking to improve 

efficiency and decrease environmental impacts. The commenter asserted that EPA failed entirely 

to consider the reduction of air emissions possible using this control technique, despite evidence 

in the record of pollution prevention techniques used at pulp and paper mills in the United 

States.92

 

88 Additional details on our technology review are provided in docket memoranda, titled Summary of Pulp Bleaching 

Technology Review and Summary of RBLC and Other Findings to Support Section 112(d)(6) Technology Review for 

Pulp and Paper NESHAP and in the European Commission document, titled Integrated Pollution Prevention and 

Control (IPPC): Reference Document on Best Available Techniques in the Pulp and Paper Industry.

89 See memorandum from K. Spence and J. Bradfield, EPA, to Docket EPA-HQ-OAR-2007-0544, titled Summary of 

Pulp Bleaching Technology Review, November 22, 2011, in the docket for the subpart S rulemaking.

90 Id., page 4.

91 See European Commission document titled, Integrated Pollution Prevention and Control Draft Reference 

Document on Best Available Techniques in the Pulp and Paper Industry, Draft April 2010, at 82.

92 See Trip Report for Site Visit – GP Big Island, LLC (EPA-HQ-OAR-2007-0544-0044) (discussing the facility‘s 

new substance review process).
74

Response: The EPA’s technology review identified two facilities with BACT emissions 

limitations that required bleaching without Cl2 or ClO2 or bleaching with only hydrogen 

peroxide, sodium hydrosulfite, and sodium borohydride. In the case of the facility that is not 

allowed to bleach with Cl2 or ClO2, the facility produces secondary pulp. This process requires 

pulp brightening which is different from bleaching, as it does not remove lignin. In the case of 

virgin kraft fibers, the lignin must be removed to obtain target final product brightnesses. In the 

case of the facility that can only process pulp using hydrogen peroxide, sodium hydrosulfite, and 

sodium borohydride, the facility is producing mechanical pulp, which also only requires 

brightening, not bleaching. These “bleaching” chemicals are not applicable to virgin kraft pulps. 

Bleach plant vent gas emissions are effectively controlled at 99 percent, and no advances in 

emission control measures for bleaching have occurred since the initial promulgation of subpart 

S in 1998.

The EPA did consider EMS, best practices, and benchmarking in the technology review. 

These systems are in place at many mills, but the scope of these systems is very mill-specific 

and, therefore, difficult to codify, much less allow quantification of the costs and emissions 

reductions associated with them. Best practices and EMS may be further investigated for the 

resolution of issues in a future rulemaking where work practices may be deemed appropriate.

5.4 Kraft Pulping Condensate Standards

5.4.1 General Comments on the Kraft Pulping Condensate Standards

62. Comment: Condensate Generation. Commenter 0162 explained that pulping process 

condensates contain varying concentrations of HAPs, of which methanol is the predominant 

HAP used as a surrogate in subpart S. These HAPs are apportioned throughout the process to the 

pulp, pulping liquors, condensates, and gas streams, also known as non-condensable gases 

(NCGs). Some methanol remains in the liquor and will be destroyed when the liquor is burned in 

the recovery furnace to recover sodium and sulfur. Throughout the process, water containing 

relatively low concentrations of methanol is sent to the wastewater treatment system (WWTS). 

For the purposes of compliance with subpart S, HAPs are collected from either the gases or 

condensates from the pulping and evaporator equipment. NCASI studied the generation and 

portioning of methanol during the development of the “Cluster Rule” (of which subpart S is the 

air portion), and NCASI Technical Bulletin 702 covers those details.

The commenter explained that processes at each mill are slightly different, and the 

differences affect the partitioning of methanol. The ability to treat condensates is governed by 

the fact that methanol has an affinity for water, and it takes a lot of energy/resources to drive 

methanol from the liquid phase. Therefore, of the condensates generated, only the concentrated 

condensate streams, generally above 2000 parts per million (ppm), which contain the 

overwhelming majority of the methanol, can be effectively treated in steam strippers.

The commenter stated that collecting and treating more process methanol results in 

greater and greater cost of destruction and makes less and less sense given the acceptable risk 

conclusion at current treatment levels. MACT was set at a more reasonable treatment efficiency

and condensate collection rate because the systems that comprised the “floor” were designed 
75

almost entirely for odor control, and these decisions were made with a necessary mind towards 

reducing odor (and, therefore, methanol and other HAPs) cost effectively.

Response: We recognize that methanol is the predominant HAP contained in kraft 

condensates, that there is variability in methanol generation, that mills treat the highestconcentration condensate streams in accordance with subpart S (and for odor control). As 

discussed further below, we did not propose, and nor are we adopting, additional collection 

requirements. We have evaluated the performance criteria and variability of treatment systems

typically used by facilities to assure compliance with the kraft pulping process condensate 

standards in §63.446. We have also reviewed the information provided by the commenter that 

supplements data collected in the ICR. The EPA has decided not to promulgate revisions to the 

kraft condensate standards upon further evaluation of the costs, energy, and secondary air 

emissions impacts associated with upgrading these systems. The commenter connects the 

conclusion of the section 112(f)(2) risk review with the proposal developed under the section 

112(d)(6) technology review. Technology reviews require the consideration of technology

changes in practices, processes and controls that have led to improved HAP control. As noted in 

the proposal, risk does not need to be a factor in section 112(d)(6) considerations and was not 

here.

63. Comment: Condensate Collection and Treatment Compliance Options in the Original 

NESHAP. Commenter 0162 explained that the MACT standard was divided into two phases of 

implementation. Phase I set limits for condensate collection and treatment and also required 

collection and treatment of LVHC NCG streams. During Phase II, mills were required to collect 

and treat HVLC NCG streams.

The commenter summarized that, in 1993, there were 32 mills with steam strippers, and 

the top 15 were used to develop the MACT “floor” (top 12 percent of all 125 mills that were 

covered by the rule). The commenter noted that the top 15 mills were all bleached mills. The 

commenter explained how an NCASI study documenting HAP collection and treatment at all 

sources (NCASI Technical Bulletin 661) identified that the best performing 15 mills collected on 

average 11.1 pounds per oven-dried ton of pulp (lb/ODTP) of methanol and achieved a treatment 

efficiency of 92 percent. Based on the average collection of methanol by the top 15 strippers, 

EPA developed the collection standard of 11.1 lb HAP/ODTP, with methanol being the surrogate 

for HAPs. (See §63.446(c)(3).) The standard was adjusted to 7.2 lb HAP/ODTP for unbleached 

mills, given that unbleached mills generate methanol at a rate that is 64 percent of the rate at 

which methanol is generated by bleached mills. (See NCASI Technical Bulletin 702.)

The commenter stated that the two primary methods for condensate treatment are 

(1) steam stripping and (2) biological treatment. At the time the “Phase 1” requirements of the 

subpart S rule were being developed, the technology used by most mills that had condensate 

treatment was steam stripping. Given the affinity of methanol to water and the fact that the 

condensates could be effectively treated by the active organisms in existing ASBs, biological 

treatment of the condensates, along with other mill wastewaters, was identified as a feasible 

alternative to attain a similar level of HAP reduction.93 The condensates had to be transported in 

 

93 Most aerated stabilization basin (ASB) systems—the most common type of wastewater treatment systems at pulp 

mills--are more difficult to operate to achieve a 92 percent destruction efficiency than steam strippers, but they also 
76

a hardpipe and introduced below the surface of the treatment system in order to minimize 

volatilization.

The commenter summarized that both the condensate collection and condensate treatment 

requirements in the subpart S rule were based on the average collection levels and performance 

of steam strippers at the best performing mills. As noted above, 11.1 lb HAP/ODTP was the 

average HAP collection of the “floor” steam strippers. As this was an average collection, it was 

noted that not even all “floor” mills could achieve a collection standard of 11.1 lb HAP/ODTP 

for bleached mills. Therefore, the “named streams” approach was developed. The “named 

streams” are locations where volatile HAPs are generated in concentrations that can be 

effectively treated.

To meet the condensate collection requirements for Phase 1, mills could either:

 Collect 11.1/7.2 lb HAP/ODTP (bleached/unbleached) from named streams, or

 Collect all “named streams” (it was noted that some mills could not generate the amount 

of methanol in the lb/ODTP standard), or

 Collect 65 percent of HAPs contained in pulping, turpentine recovery, and evaporator 

systems (based again on the average collection of “named streams” by “floor” mills) plus 

all HVLC/LVHC condensates.

(See §63.446(c).) The commenter noted that all these options required collection of “named 

streams” as identified by the rule (i.e., a mill could not take credit for collecting “unnamed 

streams”).

In addition to collection options, the commenter noted that the current subpart S rule 

offers four treatment options. These options were again developed based on the “floor” mills’ 

performance in treating an average of 92 percent in their steam strippers and the outlet 

concentration of those units. The options provided to treat the collected streams are:

 Reduce or destroy at least 92 percent by weight of the collected HAPs, or

 Remove or destroy at least 10.2 or 6.6 lb HAP/ODTP (bleached/unbleached mills), or

 Remove or destroy so the control device outlet HAP concentration is at or below 330/210 

parts per million by weight (ppmw) (bleached/unbleached), or

 Recycle condensates to an enclosed treatment system.

(See §63.446(e).) The commenter stated that, based on these requirements, facilities 

designed systems to comply with the standards with an inherent margin of safety to ensure 

continuous compliance, given both process and control device variability. In other words, mills 

designed systems to achieve some level of control beyond what was required by the rule in order 

to ensure a compliance margin and demonstrate compliance at all times (99 percent+ compliance 

probability). The commenter stated that this is why it is not surprising for the average treatment 

performance to exceed the levels required by the current standards.

 

require less routine downtime for maintenance than steam stripper technology and at less cost. The lb/ODTP 

treatment option accommodates lower treatment efficiencies if more condensate is collected and treated. These 

options grew out of the cooperative Cluster Rule effort after industry advanced wastewater treatment as an equally 

effective treatment system with lower energy requirements and downtime. Cooperative thinking is what led to the 

flexible structure inherent in the Cluster Rule and the relative “near-uniqueness” of individual mill compliance 

systems – equivalent control with the most practical design given conditions and constraints of individual mills.
77

Response: We thank the commenter for their synopsis of how the condensate standards 

in the promulgated rule were developed. We note that one of the 15 mills used in the MACT 

floor was a combination bleached and unbleached mill and another was a semi-bleached mill. 

64. Comment: Clean Condensate Alternative. Commenter 0162 explained that the MACT I

Phase 2 required collection of HVLC gases from brownstock washer systems, oxygen 

delignification systems, and some deknotters, screening systems, and deckers. As the cost to 

collect these gases was high (high volume means larger piping systems and control devices that 

can handle the volume), the Agency developed the CCA. This option allowed a mill to collect 

and treat additional condensates (named or unnamed streams) in order to achieve emissions 

reductions equivalent to those required from “Phase 2” of the rule for control of HVLC systems. 

(See §63.447.)

Facilities demonstrating compliance using CCA had to quantify emissions under a 

baseline scenario that reflected MACT I Phase I compliance. Facilities were not allowed to take 

credit for emission reductions resulting from compliance strategies chosen for MACT I Phase 1. 

For example, consider a bleached mill complying with the 11.1 lb HAP/ODTP collection 

requirement and demonstrating the need for 10 percent over-collection (12.21 lb/ODTP) in order 

to increase compliance probability and establish averaging times. Subsequently, this level of 

collection would be treated as the baseline for CCA, and the mill would have to achieve 

additional and surplus emissions reductions to offset not collecting the HVLC streams identified 

in the rule, if additional condensates were chosen to be collected and treated under the millspecific CCA compliance program.

94 In order to demonstrate compliance under this option, in 

this example, a mill would have to collect additional condensates over the example 12.21 lb 

HAP/ODTP baseline and achieve an emissions reduction equivalent to the emissions reductions 

that would have been achieved by controlling the HVLC sources identified in Phase 2. A more 

complete example of an approach to CCA was described in Attachment 6 provided with 

comment 0162.

Response: We thank the commenter for their overview of the rationale for the CCA

standards included in subpart S, and for the example CCA compliance option provided in 

Attachment 6 to their comment (0162).

65. Comment: Setting a HAP-Specific Standard instead of a Total HAP Standard. 

Commenter 0218 objected to the EPA’s proposed total HAP standards for kraft condensates, 

stating that section 112(d)(6) requires EPA to control each emitted HAP. The commenter 

asserted that the EPA had not stated that it was using total HAP as a surrogate for all emitted 

HAPs, as required, in order to be able to meet the test for a surrogate. The commenter further 

argued that the EPA had not demonstrated that total HAP is a valid surrogate, which would 

require that:

1. The target HAP is “invariably” present in the surrogate pollutant;

 

94 See letter from R. Douglas Neeley, EPA Region IV, to Larry Webber, Georgia EPD, March 27, 2003. “Any extra 

streams or additional mass of condensate used as an operating cushion, or for determining the need for flexibility 

provided by a longer averaging time, cannot be used as credit for the CCA, since it was granted and used to meet the 

collection requirements of § 63.446.” 
78

2. Methods to control or capture the surrogate pollutant “indiscriminately” control or 

capture the target HAP as well; and

3. The controls for the surrogate are the “only means” by which facilities “achieve” 

reductions of the target HAP. 

The commenter stated that was unclear if the EPA considered other means that plants use to 

reduce each HAP, such as the use of cleaner raw materials, different processes, or control 

technologies.

The commenter observed that there is an extremely long list of pollutants emitted by the 

pulp and paper source category, ranging from methanol, acetaldehyde, formaldehyde, benzene, 

glycol ethers, and POM to cadmium, lead, nickel, mercury, and manganese. The commenter 

stated that, considering this broad range of emitted pollutants, EPA cannot simply assume that 

the kraft condensate standards will appropriately control all HAPs simply because it has set a 

total HAP standard.

Response: Methanol was selected as the surrogate compound for measuring total HAP 

for most control devices since it is the predominant HAP in process vent and wastewater streams. 

Compliance demonstration based on methanol was found to be sufficient and meet the noted 

surrogacy requirements for gaseous streams. However, the 1998 final rule specified that total

HAP must be measured when demonstrating compliance using biological treatment (or the CCA) 

for pulping process condensates. In the 1998 final rule, EPA explained that:95

“Because methanol is one of the most difficult HAPs to remove with a steam stripper (the 

technology on which the standards are based), even greater removals of total HAP would 

occur when a steam stripper is used. Thus, methanol is a reasonable surrogate under such 

conditions. The opposite is true for biological treatment systems, where methanol is one 

of the easier HAPs to degrade. As such, the final regulation specifies that a total HAP 

removal (not just methanol) of 92 percent be achieved by biological treatment systems.”

The 1998 final rule did not refine EPA's definition of total HAP for this category. 

Additional data to establish a specific list of the 188 HAPs for compliance testing became

available following promulgation of the 1998 final rule. NCASI submitted to EPA a study96 that

showed that the regulated condensate streams contain a finite number of measurable HAPs. The 

NCASI data reported that the HAP compounds with concentrations greater than 1 ppmw in 

regulated condensate streams are methanol, methyl ethyl ketone (MEK), acetaldehyde, and 

propionaldehyde; and that methanol accounts for approximately 98.5 percent of the total HAP 

mass, with acetaldehyde, MEK, and propionaldehyde accounting for the remaining 1.5 percent.

Therefore, on January 25, 2000, we proposed a procedure (the “methanol procedure”) for use as 

an alternative to demonstrating compliance of biological treatment systems on an individual 

HAP basis. As part of the methanol procedure, mills were required to measure the ratio (“r”) of 

non-methanol HAP (acetaldehyde, MEK, and propionaldehyde) mass to methanol mass.(65 FR 

3911) This procedure was finalized on December 22, 2000 (65 FR 80755).

 

95 See 63 FR pages 18511 and 18524, April 15, 1998.

96 Hazardous Air Pollutants Present in Kraft Mill Condensates and their Significance for the Hard-piping Option 

under Maximum Achievable Control Technology (MACT), December 1998. Docket No. A-92-40, Item No. VI-D-1.
79

We believe our analyses have satisfied the criteria listed by the commenter. We note that 

compliance equations discount any control of non-methanol HAP unless it can be demonstrated 

directly. In other words, mills often over-control methanol to demonstrate compliance if they

cannot demonstrate destruction of non-methanol HAP in condensate streams. We also note that

HAPs are primarily generated at pulping operations from the wood raw material, not solvents or 

additives, so those criteria is not applicable here.

66. Comment: Commenter 0163 requested a public announcement of a new proposal if EPA 

were to reanalyze the ICR data and reach another set of proposed conclusions about some 

incremental improvement in overall HAP reduction, so that an opportunity to comment is 

afforded. The commenter noted that they would expect for any proposal to discuss rule 

provisions for adjusting averaging times, since averaging time is critical for achievability of a 

condensate collection standard and also must be considered directly linked to the treatment 

standard. The commenter noted that EPA would also need to consider the need for mills to 

develop achievable strategies for adequate compliance margin in any adjustment of the standard 

it proposes.

Response: We have reanalyzed the ICR data and considered information provided by

commenters that supplements data in the ICR. Based on our independent review, we have 

decided not to revise the kraft condensate standards at this time. No new proposal is required.

5.4.2 Technology, Proposed Numerical Limits, and Variability Associated with Kraft 

Condensate Collection and Treatment

67. Comment: Kraft Condensates Standard Insufficiently Stringent. Commenter 0218 stated 

that, although EPA did recognize that current processes and controls are capable of achieving 

greater reductions, EPA failed to set a standard that satisfies section 112(d)(6) or section 

112(d)(2)-(3). The commenter observed that, while the EPA found that only 15 mills would need 

to improve their efficiency under the new 94 percent control of total HAP from kraft 

condensates, EPA found that of 171 mills, more than 100 would not be affected by updating the 

standard to 98 percent–presumably because they are already achieving that level of control. The 

commenter noted that the EPA still only proposed a 94 percent standard because of cost ($4 

million per year, or $1,000 per ton of HAP control cost effectiveness).

The commenter cited two reasons why EPA failed to set an updated MACT floor based 

on the emission reductions achieved by the best-performing sources. First, the commenter stated 

that percent reduction standards are unlawful under section 112 because they do not reflect the 

emission level achieved by the best performing sources, just what EPA thinks can be achieved 

through the use of certain control technology. In support of this argument, the commenter cited

the Portland Cement NESHAP (Sept. 9, 2010), Coal- and Oil-Fired Electric Utility Steam 

Generating Units NESHAP (Feb. 16, 2012), and Fossil-Fuel-Fired Electric Utility, IndustrialCommercial-Institutional, and Small Industrial-Commercial-Institutional Steam Generating 

Units NSPS, (Feb. 16, 2012) as examples of where the EPA has maintained that a percent 

reduction format negates the contribution of HAP inputs to source performance and “may be 

inconsistent with the D.C. Circuit Court’s rulings as restated in the Brick case (479 F.3d at 880) 

which say, in effect, that it is the emissions achieved in practice (i.e., emissions to the 
80

atmosphere) that matter, not how one achieves those emissions.” The commenter emphasized 

that a percent reduction standard is inconsistent with and violates section 112’s basic 

requirement to set standards based on the emission reductions achieved, regardless of the method 

used to do so. The commenter recommended that the EPA review each element of the standards 

that contains an unlawful percent reduction standard and perform the required analysis under 

section 112(d) to ensure emission reductions will occur based on what the best performers have 

achieved and based on what is now achievable.

Second, the commenter stated that, rather than setting a MACT floor based on the greater 

reduction levels achieved at the best performing units in accordance with section 112(d)(6) and 

section 112(d)(3), the EPA skipped the floor-updating step and proceeded to consider costs–a 

step that is only proper when setting limits “beyond-the-floor.” The commenter, citing National 

Lime Ass‘n v. EPA,233 F.3d 625, 640 (D.C. Cir. 2000); and NRDC v. EPA, 489 F.3d 1364, 1375-

76 (D.C. Cir. 2007), argued that the MACT “floor” must be determined “without regard to costs 

or other factors and methods listed in section 7412(d)(2).” The commenter expressed concern 

that costs were a central component of EPA’s analysis of achievable control, and stated that cost 

is not appropriate for reviewing and setting a MACT floor standard. The commenter urged the 

EPA to rectify this error in the final rule by considering reductions “achieved” and “achievable” 

from all “developments” in this sector, and setting the updated MACT standard pursuant to 

section 112(d)(6). The commenter concluded that failing to set a more stringent standard due to 

cost alone is unlawful and arbitrary and capricious.

Commenter 0218 further stated that, even if EPA could consider costs, its choice of a cost 

threshold was arbitrary and capricious. The commenter contended that even if EPA could skip 

the floor-setting process and proceed directly to set limits to provide an adequate margin of 

safety, its choice of a cost threshold was arbitrary and capricious. The commenter considered the 

EPA’s determination of control efficiency for existing kraft condensate treatment to be minimal, 

when higher levels of control would also provide an adequate margin of safety at a reasonable 

cost. The commenter notes that for the Secondary Lead Smelting NESHAP, the EPA found a 

cost of $1.5 million per ton, or $750 per pound to be reasonable, a higher cost than a nationwide 

reduction of over 12,000 tons of HAPs per year from kraft condensate that is achievable at a cost 

of only $2,700 per ton.

Response: At the outset, the commenter indicated that the proposal overlooked the core 

information concerning the applicability of the proposed changes. There is a misunderstanding 

regarding the affected universe of kraft pulp and paper mills. There are 171 major sources, but 

only 97 of those have kraft pulping operations subject to the kraft condensates standards.97 Of the 

97 kraft pulping mills, we projected at proposal that 15 mills would need to make improvements 

in condensate collection and/or treatment to raise their control level to 94 percent. The 

commenter then proceeded to indicate that they believed that EPA was obligated to recalculate 

the MACT floor and set the new control requirements at 98 percent, the reported levels indicated 

by the better performing units in the ICR conducted for the rulemaking.

 

97 See memorandum from J. Bradfield and K. Spence, EPA, to Docket EPA-HQ-OAR-2007-0544, titled Summary of 

Kraft Condensate Control Technology Review, October 23, 2011, in the docket for the subpart S rulemaking.
81

As noted above, EPA does not believe a section 112(d)(6) technology review obligates 

the Agency to recalculate MACT floors or otherwise reconsider what the best performing 

sources can achieve as if this were a repeat of the section 112(d)(2) and (d)(3) analysis. Instead, 

we read this provision as providing the EPA with substantial latitude in weighing many factors to 

arrive at the appropriate balance in considering revisions. The central point of our analysis first 

analyzed performance of condensate treatment units, not cost, as suggested by the commenter.

98

The selection of a 94 percent control level for proposal reflected our consideration of treatment 

system performance (as we understood it at proposal), as well as our proposal estimates of cost, 

HAP reductions, energy impacts, secondary air emissions impacts, and small business impacts. 

The commenter also indicated that they believe standards should be set based on 

“emissions achieved” rather than a percentage reduction. We disagree, though we would note 

that the proposed rule includes a mass per production volume reduction option and a ppm limit 

for control demonstration, which were both adjusted to reflect equivalence to a 94 percent

reduction standard at proposal. The commenter does not explain their reasoning behind a general

objection to percent reduction-based standards. One objection we have received in previous 

comment is that such standards could presumably facilitate production increases that generate 

additional emissions, even after the required percentage control is achieved. In the case of kraft 

condensate generation, such a concern would not have foundation. In fact, condensates represent 

the residue of HAP that precipitate out in high-moisture atmosphere gas streams, the noncondensable portion of which is incinerated. There is no economic advantage to generating more 

(or fewer) condensates. Furthermore, the regulations cited by the commenter as examples where, 

according to the commenter, EPA has maintained that a percent reduction format negates the 

contribution of HAP inputs to source performance, are all standards affecting combustion 

sources (e.g., cement kilns, boilers) that can have fuel-related emissions. The mechanisms for 

reduction of fuel-related combustion emissions are not the same as for HAP emissions from 

process liquids.

Lastly, the commenter found our choice of cost thresholds arbitrary and capricious, citing 

our Secondary Lead Smelting NESHAP. While we agree that different thresholds were used in 

the Secondary Lead Smelting NESHAP, the choices of cost thresholds will vary based on the 

type of regulatory analysis performed and, with respect to risk assessment, our assessment of risk 

acceptability. There were two reasons we chose different cost thresholds in this rulemaking.

First, in this case, the cost choices in the proposal were made under the section 112(d)(6) 

technology review, where, as we note above, EPA has ample latitude regarding cost 

considerations, not under a risk-based ample margin of safety analysis. Second, the commenter’s 

analogy draws a comparison to an analysis for a PB-HAP in the Secondary Lead NESHAP RTR,

where the risks were judged to be unacceptable. As noted in the proposal preamble, and 

discussed elsewhere in this document (see section 4.2.4), the pulp and paper subpart S source 

category was not found to have PB-HAP significant enough to require a multipathway risk 

assessment, and the risks for the subpart S category evaluated under section 112(f)(2) were found 

to be acceptable.

68. Comment: Opposition to Increasing Stringency of Kraft Condensates Standard. Several 

commenters (0162, 0163, 0165, 0167, 0170, 0172, 0207, and 0212) opposed increasing the 

 

98Id..
82

stringency of the kraft pulping condensate treatment requirements. Commenter 0162 stated that 

EPA had not justified or supplied information in the docket that documented or justified the 

proposed increase in treatment efficiency to 94 percent. The commenter noted that EPA’s 

documentation states “the average percentage removal of kraft condensates was 96.2 percent,” as 

the sole basis for the proposed increase in treatment requirements.99 The commenter claimed that 

EPA did not evaluate the control technologies used for compliance with subpart S and the ability

for these systems to perform at higher efficiencies, nor did EPA identify the changes needed to 

the MACT floor technologies to achieve these higher efficiencies. The commenter stated that

EPA had misinterpreted the ICR data and not taken into account system variability, the need for 

compliance margin, or the higher standard currently required by wastewater treatment systems. 

Therefore, it was inappropriate for the Agency to propose a higher standard without evaluating 

the current limits of the control systems in place or documenting how facilities would comply

with the proposed standards.

Commenter 0163 agreed with the EPA’s assessment that there are no advances that could 

become the basis for revised treatment options for condensate HAP reductions. The commenter 

stated that the EPA analyses of the 2011 pulp and paper ICR concluded that all kraft pulp mills 

are performing at a higher level of control than the 92 percent minimum required and 

consequently that the technology has advanced since the 1998 MACT rule to warrant the 

development of an updated standard. The commenter stated that the EPA subsequently

developed an “equivalency calculation” that framed a series of higher percent control options 

and translated these into the optional numerical lb/ODTP and ppm treatment limits as already

structured in the current rule. The commenter stated that EPA proposed limits based on their 

calculation of a 94 percent control efficiency. The commenter concluded (based on their 

independent review and from the reports provided by NCASI) that EPA had misinterpreted the 

ICR data and reached an inappropriate conclusion. 

According to commenter 0163, the fact that EPA did not uncover any new or advanced 

control technology was an initial flag regarding EPA’s subsequent proposal. A second flag was a 

significant anomaly resulting from EPA’s path forward from what appears to be a flawed 

analysis that would result in HAP reductions exceeding the condensate HAP collection standards 

in §63.446(c). The commenter attached NCASI’s interim analysis (comment 0163.1 and 0163.2).

Commenter 0165 stated that the technology review is flawed, and there have been no 

significant technical advances in the past decade. The commenter disagreed with the EPA’s 

requirement of further reductions in the pollutant methanol, stating that methanol is of 

questionable hazardous impact. The commenter asserted that the pulp and paper industry is 

already facing significant requirements for Boiler MACT and should not be required to make 

further expenditures for no improvement.

Commenter 0172 commented that controls at their mills that were installed for MACT 

were the latest technologies, and that no newer technologies are known that would enable 

additional methanol removal and treatment from process condensates. The commenter strongly 

endorsed the comments of NCASI that EPA inappropriately used data from industry responses to 

the Part I ICR when deciding to raise the required destruction efficiency for steam strippers from 

 

99 Id.
83

92 percent to 94 percent. The Agency did not adequately analyze data from facilities using the 

CCA, or those having high-rate biological treatment systems, and did not consider operational 

and seasonal variability, or degradation in the performance of steam strippers over time. After 

properly discarding these outlier facilities from the database, the remaining data set represents a 

very limited number of mills and thus fails to provide a sufficient basis for revising the 

condensate treatment standard.

Commenter 0172 also stated that EPA failed to use the correct calculation methodology

to derive the proposed new lb/ton limits in several ways. First, EPA inappropriately extended the 

25 percent increase in percent destruction efficiency to the mass destruction standards. Second, 

EPA did not fully evaluate the regulatory or economic impacts of modifying the mass destruction 

requirements. The EPA appeared to have simply evaluated the mass destruction values 

calculated during the initial performance tests and reported in the ICR submittals and then 

concluded that most facilities would be able to comply with this “average” value. The Agency

did not consider that normal process variability causes facilities to be either over or under this 

destruction value on a daily basis. This was a critical oversight, as compliance with the standard 

must be demonstrated on a daily basis. Unless this normal process variability is considered, some 

mills will be out of compliance a statistically significant portion of the time.

Response: We have reviewed the ICR data identified as a “misinterpretation” and made 

the appropriate adjustments to our evaluation in the final rule. The commenter appears to 

misunderstand some of the components of our analysis. They indicate a belief that the lack of 

new control technology application is significant in our analysis. It is not. As noted elsewhere in 

this section, our analysis focused on the “practice” of existing technology, put in place with the 

MACT rule and evaluated whether there were advances in the application of that control 

technology. Additionally, the commenter noted that they believe methanol’s hazardous impact is 

questionable. Regarding risk, our decision related to the hazard of methanol (and other HAPs) 

was considered under our two-step assessment process and found acceptable. However, our 

control decisions for kraft condensates were made within the context of a section 112(d)(6) 

technology review. Methanol is a HAP, HAP control was the basis of the MACT floor, and using 

methanol as the basis for this analysis is appropriate.

Nevertheless, EPA has reanalyzed the condensate treatment technology performance 

levels in light of information provided by the commenter. We reviewed the additional cost and 

control information provided by the commenter, information that supplements data collected in 

the ICR. We reanalyzed the condensate treatment technology performance. The condensate 

treatment technology performance levels, costs, and impacts used in our final analysis for 

promulgation are included in the docket and summarized elsewhere in this document (e.g., in this 

section and in section 11).100 Our reanalysis of the kraft condensate standards and impacts 

considered (among other things) the following:

 Regulatory options for 93 and 94 percent HAP removal (as compared to the baseline of 

92 percent);

 

100 See memorandum from T. Holloway, K. Hanks, and C. Gooden, RTI, to J. Bradfield and B. Schrock, EPA, titled 

Costs, Environmental, and Energy Impacts for the Promulgated Subpart S Risk and Technology Review, May 15, 

2012, in the docket for the subpart S rulemaking.
84

 No change in the condensate collection requirements, and clarified through revised 

lb/ODTP and ppmw treatment limits;

 Variability in treatment system performance;

 Potential impacts of condensate HAP concentrations on CCA mills using approaches 

involving process water; and

 Energy and secondary air emissions impacts for new and upgraded steam strippers.

The EPA has decided not to promulgate revisions to the kraft condensate standards upon further 

evaluation of the costs, energy, and secondary air emissions impacts associated with upgrading 

condensate treatment systems.

69. Comment: Technology Unchanged for Condensate Treatment. Commenter 0162 agreed 

with EPA’s determination that its “technology review of kraft condensates did not yield any

information about new technologies that could become the basis for regulatory options” (76 FR 

81345). According to commenters 0162 and 0172, the technology used by the industry for 

subpart S compliance is the same as when the rule was promulgated. Commenter 0162 stated that 

these systems have the same capabilities as the units that were used by the “best performing” 

mills that were the basis for the MACT “floor.”

However, commenters 0162 and 1072 disagreed with EPA’s proposal preamble statement 

that, “[f]or kraft pulping condensates, we have determined that the technology has sufficiently 

advanced since the 1998 MACT rule to warrant the development of an updated standard” (See 

76 FR 81344). Commenter 0162 stated that CAA section 112(d)(6) directs EPA to “review, and 

revise as necessary...[the initial MACT standards] (taking into account developments in 

practices, processes, and control technologies)” (emphasis added). The EPA has now proposed to 

revise the condensate treatment requirements, not because the Agency has identified any new 

developments in processes or treatment technologies beyond what EPA identified when 

establishing the MACT floor, but simply because EPA believed it had data indicating that 

wastewater treatment systems and steam strippers achieve control efficiencies greater than the 92 

percent that the current MACT rules require. First, there is no support of the Agency’s 

conclusion in the available data.101 Additionally, even if this were true, this is not a sufficient 

finding to warrant revising the MACT standards pursuant to section 112(d)(6) (and EPA lacks 

any other authority for revising the subpart S MACT standards102).

 

101 Interim comments on rationale and methodologies used to evaluate and propose increased treatment requirements 

for kraft condensates in the Pulp and Paper ICR, NCASI Memo to Ms. Robin Dunkins, Mr. John Bradfield, Mr. Bill 

Schrock, February 17, 2012. – This memo outlines other factors to be considered while reviewing condensate 

treatment data reported in the ICR and why it is inappropriate to attribute the performance to technological or 

operational improvements. – The contents of the NCASI memorandum are discussed and provided as Attachment 4 

to comment 0162.

102 Congress structured section 112 unlike other provisions of the CAA (and other environmental statutes). Under 

CAA sections 112(c)(2) and 112(e), EPA was given definite deadlines for promulgating MACT standards for 

various source categories. The MACT “floor” thus represented performance at a specified point in time. Congress 

did not give EPA authority to review periodically the performance achieved by the “best performing” facilities, but 

only to determine, at least every eight years after the MACT “floor” was established (and any more-stringent 

“beyond-the-floor” MACT standards were justified), whether it is necessary to revise the MACT standards to 

account for “developments in practices, processes, and control technologies.”
85

Commenter 0162 contended that analysis of stripper performance test data in the docket 

was inadequate and that EPA lacked an understanding of what the data represent. The test data 

were not summarized to the extent that they could be verified by the companies that submitted 

such data within EPA’s massive ICR effort. Individual test data were not even listed in the 

docket. The commenter asserted that the data were largely initial compliance test data as required 

by the rule. These tests confirm compliance with the rule with a necessary margin to assure 

compliance over the range of operating conditions the stripper will see. The same is true of 

analogous wastewater treatment system controls. A margin of compliance determined under 

initial performance test conditions verifies proper design and construction of the equipment and 

not that “technologies have advanced.” Further, the commenter could find no adequate 

description in the record on how EPA was considering to modify stripper and wastewater 

treatment systems to achieve a higher 94 percent destruction efficiency, while maintaining a 

margin and certainty of compliance needed for operation over the range of conditions present. 

Finally, the calculated lb/ton compliance option requirements, purportedly consistent with the 94 

percent efficiency objective, could not be achieved, in any way the commenter could determine, 

without more than doubling the investment in control equipment. The commenter concluded that

the logic employed in developing the lb/ton proposed requirements was clearly flawed.

Commenter 0162 stated that when the statute directs EPA to revise MACT standards only 

where “necessary...taking into account developments” in process and control technology, EPA 

must identify specific changes in the applicable technology that necessitate a change in the 

standard, and that EPA has not done so here. The commenter stated that neither the preamble to 

the proposed rule nor any document they could identify in the docket described new control 

technology for pulp mill condensates, nor even advances in the condensate collection and steam 

stripper technology that was the basis for existing condensate treatment standards. Rather, EPA 

had concluded that it could set a more-stringent limit that could be met by some mills using the 

same technology that was the basis of the existing MACT standards. The commenter asserted 

that Congress clearly did not intend for section 112(d)(6) to authorize that sort of tightening of 

the standard that companies have already taken the steps to meet, absent a specific change in 

available technology. (Moreover, as EPA has already acknowledged, even if new, more effective 

treatment technology were available, EPA would still need to consider the cost effectiveness of 

that technology and other factors (See NRDC v. EPA, 529 F.3d 1077, 1084 (D.C. Cir. 2008)). 

The commenter contended that EPA had not conducted that sort of analysis here.

Commenter 0162 stated that the only fact EPA relied on to propose revised standards, 

purportedly under authority of CAA section 112(d)(6), was that some mills are achieving HAP 

removal rates greater than the 92 percent MACT removal rate. The commenter noted that it 

would be surprising if mills were meeting the MACT standards at all times and with a very high 

compliance probability and yet on average had treatment efficiencies no higher than the minimal 

efficiency necessary to comply with the existing MACT standards. For instance, sound 

engineering and environmental control practices would require a steam stripper to be designed 

and operated with removal efficiency greater than 92 percent to assure compliance at all times. 

The commenter asserted that nothing in the language of section 112(d)(6), the legislative history

of section 112, or common sense suggests that Congress wanted EPA to constantly “ratchetdown” the MACT standards, removing the margin of compliance that facilities have built into 

their HAP control systems. The commenter stated that adjustments are appropriate only when 

there are advances in practices, processes, or control technologies.
86

Response: We disagree with the commenter’s interpretation of our legal authority

concerning setting tighter standards for kraft condensates under CAA section 112(d)(6). As 

noted above, we interpret section 112(d)(6) as essentially requiring us to consider all

developments in practices, processes, and control technologies in the industry. When we take 

into account the “developments in practices, processes, and control technologies,” we interpret 

that language as a requirement not only to evaluate new control technologies and process 

improvements but also to evaluate the application of existing control technologies that were the 

basis of the MACT floor. In that evaluation we examine whether, in the ‘practice’ of applying 

the MACT floor technology, there have been technological advances. Generally, we consider 

whether the MACT floor technology, in practice, is consistently performing better than 

anticipated in the original MACT floor analysis. Indeed, we did not find in our evaluation of data 

received in the ICR conducted prior to proposal that there were significant modifications to the 

basic kraft pulping process or new technologies for control of condensates. In the proposal, our 

initial evaluation indicated that kraft condensate control, using the technologies originally 

anticipated had improved since promulgation. Consequently, we proposed to raise the treatment 

standard from a 92 percent control basis to a 94 percent basis.103 However, as discussed 

previously, we have since reevaluated the data in light of information provided by the 

commenter.

Discussions with industry representatives ensued shortly after the proposal was published 

in the Federal Register on December 27, 2011, when industry representatives began expressing 

their concerns with the proposal. The EPA met with industry representatives to discuss the kraft 

condensate standards on January 12, March 16, March 28 and May 2, 2012. Minutes for these 

meetings were placed in the docket soon after each meeting occurred.104 In response to the 

commenters’ request for additional information on EPA’s analysis, EPA provided a spreadsheet 

on January 12, 2012 showing the data that EPA used in developing the proposed revisions to the 

condensate limits.105 We reanalyzed the condensate treatment technology performance levels in 

light of information provided by the commenter, which supplements the ICR. The condensate 

treatment technology performance levels used in our final analysis for promulgation are also 

included in the docket.106 Our reanalysis of the kraft condensate standards considered the 

following:

 Regulatory options for 93 and 94 percent HAP removal (as compared to the baseline of 

92 percent);

 No change in the condensate collection requirements, and clarified through revised 

lb/ODTP and ppmw treatment limits;

 Variability in treatment system performance; and

 

103 See memorandum from J. Bradfield and K. Spence, EPA, to Docket EPA-HQ-OAR-2007-0544, titled Summary 

of Kraft Condensate Control Technology Review, October 23, 2011, in the docket for the subpart S rulemaking.

104 See U.S. EPA documents titled, Meeting notes for the January 12, 2012 meeting with AF&PA; Meeting notes for 

the March 16, 2012 meeting with AF&PA; Meeting notes for the March 28, 2012 meeting with AF&PA; and 

Meeting notes for the May 2, 2012 meeting with AF&PA, in the docket for the subpart S rulemaking.

105 See U.S. EPA document, titled Materials for January 12, 2012 Meeting with Pulp and Paper Industry 

Representatives to Discuss the December 27, 2011 Pulp and Paper RTR Proposal; Part I.

106 See memorandum from T. Holloway, K. Hanks, and C. Gooden, RTI, to J. Bradfield and B. Schrock, EPA, titled 

Costs, Environmental, and Energy Impacts for the Promulgated Subpart S Risk and Technology Review. May 15, 

2012, in the docket for the subpart S rulemaking.
87

 Potential impacts on CCA mills using approaches involving process water of condensate 

HAP concentrations 

We did not propose, and nor are we adopting, additional collection requirements. The EPA has 

decided not to promulgate revisions to the kraft condensate standards upon further evaluation of 

the costs, energy, and secondary air emissions impacts associated with upgrading these systems.

Regarding the commenter’s concern that data supporting the proposal analysis were not 

available in the docket, we note that our analysis of the kraft condensate standards at proposal 

was documented in a memorandum, “Summary of Kraft Condensate Control Technology 

Review” (EPA-HQ-OAR-2007-0544-0128).

70. Comment: Clarification of the Proposed Numerical Limits. Commenters 0162 and 0167 

stated that the numerical HAP treatment levels EPA proposed are greater than the current HAP 

collection requirements. The commenters stated that the proposal to increase the required HAP 

reduction (e.g., from 10.2 lb/ODTP in the current rule to 12.8 lb/ODTP, for bleached kraft mills 

and from 6.6 lb/ODTP in the current rule to 8.3 lb/ODTP, for unbleached kraft mills) is not 

consistent with the proposed rule’s stated basis: that the removal efficiency can be increased 

from the 92 percent to 94 percent and that no additional condensates need to be collected.

Commenter 0162 noted that in the equivalency calculation used to arrive at these 

numerical limits, EPA calculated the percent increase in control for each 1 percent increase in 

treatment efficiency from 92 percent to 98 percent (the level of control achieved for mills 

choosing the condensate recycling option). The commenter represented EPA’s rationale 

graphically in Figure 1 below: 

Figure 1. EPA Calculation Methodology

(Submitted by Commenter 0162)

Using this approach, the percent “standard improvement”107 corresponding to an increase 

in treatment efficiency from 92 percent to 94 percent would be 2 percent of the maximum 

possible 8 percent = 2/8 = 25 percent. Using this approach, the percent “standard improvement” 

for each 1 percent increase in treatment efficiency (from 93 percent to 98 percent) would be:

 At 93% - 1 percent of max possible 8% = 1/8 = 12.5%

 

107 See memorandum from J. Bradfield and K. Spence, EPA, to Docket EPA-HQ-OAR-2007-0544, titled Summary 

of Kraft Condensate Control Technology Review, page 4, October 23, 2011, in the docket for the subpart S 

rulemaking.
88

 At 94% - 2 percent of max possible 8% = 2/8 = 25%

 At 95% - 3/8 = 37.5%

 And so forth

These percent “standard improvements” were subsequently directly applied as scaling 

factors to arrive at numerical treatment limits in Table 2 in the October 23, 2011 memo.

As discussed during the meeting between EPA and AF&PA on Jan 12, 2012, the 

commenter contended that the above methodology of calculating numerical limits is inconsistent 

with the premise behind the equivalency approach. The commenter provided the following

insights from the equivalency approach highlight this issue:

 The scale ranging from 92 percent to 100 percent is the treatment scale.

 Assuming that whatever is not treated/controlled is released as emissions, emissions 

would reduce from 8 percent to 0 percent as treatment increases from 92 to 100 percent.

 The percent “standard improvements” calculated above are, in effect, emissions 

reductions.

 In other words, a 2 percent increase in the numerical treatment efficiency standard is 

equivalent to a 25 percent reduction in associated remaining emissions.

 When calculating numerical treatment limits, the applicable scaling factors should 

therefore reflect the original treatment scale and not the percent “standard improvement” 

(emissions) scale. As done in the original rulemaking, the lb/ODTP treatment 

requirement is simply calculated by multiplying the collection requirement by the 

proposed percent control efficiency, as shown in Figure 2 below.

Figure 2. AF&PA Recommended Calculation Methodology

(Submitted by Commenter 0162)

Commenters 0162 and 0167 stated that the numerical treatment standards corresponding 

to the 94 percent treatment level can be calculated directly as shown below and are represented 

on the treatment scale in Figure 2 above.

 7.2 lb/ODTP x 0.94 = 6.8 lb/ODTP for unbleached mills

 11.1 lb/ODTP x 0.94 = 10.4 lb/ODTP for unbleached mills
89

Commenter 0162 provided an alternate approach to calculating these numerical treatment 

levels that is logically consistent with applying EPA’s statements about increasing treatment 

efficiency from 92 to 94 percent using the percent “standard improvement” scale as follows:

 Collection levels are 7.2 lb/ODTP and 11.1 lb/ODTP (unbleached and bleached 

respectively).

 At 92 percent, the treatment levels are 6.6 lb/ODTP and 10.2 lb/ODTP.

 Therefore, when increasing the treatment standard from 92 percent to 94 percent, you 

achieve a 25 percent “standard improvement” (reduction in emissions).

 6.6 + 25% of (7.2 – 6.6) = 6.8 lb/ODTP – unbleached mills

 10.2 + 25% of (11.1 – 10.2) = 10.4 lb/ODTP – bleached mills

In developing the ppmw option that equates to 94 percent removal, commenter 0162 

stated that EPA used the correct calculation methodology. For example, the current standard for 

bleached mills is 330 ppmw at the outlet of the control device. Since this standard was based on 

a treatment efficiency of 92 percent, it would be assumed that the inlet condensate concentration 

is 4125 ppmw (330 / (1-0.92)). If the treatment standard were raised to a level of 94 percent, the 

outlet concentration would need to be lower than 248 ppmw108 (4125 ppmw x (1-0.94)).

Commenter 0162 noted that EPA calculated that the rule would result in the reduction of 

4,000 tons of HAP emissions per year. Based on the assumption that 97 mills produce an average 

1,000 ODTP per day (d) and the average decrease in emissions would be 0.2 lb/ODTP 

(equivalent increase in the standard calculated using the AF&PA methodology), the result is a 

reduction of approximately 3,500 ton HAP per year (yr), which is in line with the EPA estimate.

In addition, commenter 0172 also stated that EPA’s currently proposed lb/ton limits are 

actually above the amount of condensate that mills are required to collect in the first place (11.1 

lb/ton for bleached mills and 7.2 lb/ton for unbleached mills). The mass collection requirements 

were originally developed after evaluating available HAPs in each condensate stream, which 

streams could be economically treated, and variability of those streams. The EPA did not 

propose to raise these collection requirements. Thus, the Agency cannot legally or logically 

promulgate a destruction standard that is higher than the present collection requirement. Should 

EPA promulgate the proposed lb/ton limits along with the new destruction standard 

notwithstanding these comments, the effect would be to require bleached mills to collect 13.6 

lb/ton (12.8 ÷ 0.94) and unbleached mills to collect 8.8 lb/ton (8.3 ÷ 0.94). These collection 

amounts are far above the 11.1 lb/ton and 7.2 lb/ton MACT floors that were established in the 

original Cluster Rule. The commenter contended that EPA does not provide any justification to 

modify these MACT floor limits and thus cannot promulgate these flawed numbers. The 

commenter stated there have been no “developments in practices, processes and control 

technologies” as required by section 112(d)(6) in kraft pulping in the last 10 years that would 

justify a change in the condensate collection MACT floor. Commenter 0172 stated that these 

numbers, in many mills, are above the amount of regulated condensates that are routinely

available to collect from their regulated processes. Several of the commenter’s mills would be 

 

108 See memorandum from J. Bradfield and K. Spence, EPA, to Docket EPA-HQ-OAR-2007-0544, titled Summary 

of Kraft Condensate Control Technology Review, page 4, October 23, 2011, in the docket for the subpart S 

rulemaking.
90

unable to meet either the collection or destruction standards simply because the process is not 

able to generate enough methanol or the mill’s condensate treatment system (stripper) is not 

capable of treating more condensate. Specific data from the commenter’s kraft mills provided in 

Table 5 below demonstrate that several mills would face significant periods of non-compliance 

with the collection standard should EPA raise the destruction standard.

Table 5. Data on Methanol Collection and Percent of Time below De Facto Proposed 

Collection Standard from Georgia-Pacific Kraft Mills

(Submitted by Commenter 0172)

Mill

Average 

Methanol 

Collection, 

lb/ton

Percent of Time Below 

De Facto Proposed 

Collection Standard Comments

Cedar Springs, GA 10.6 13% Mill’s stripper at maximum capacity, no 

opportunity for treating additional condensates

Palatka, FL 13.2 23% Very limited opportunity for additional collection

Crossett, AR 14.2 32% Collecting all named streams, no opportunity for 

collecting additional condensates

Monticello, MS 8.6 49% Very limited opportunity for additional collection

Port Hudson, LA 13.3 61% Collecting all named streams, no opportunity for 

collecting additional condensates

Brunswick, GA 11.8 95% Mill’s stripper

Camas, WA 13.2 92% Collecting all named streams, no opportunity for 

collecting additional condensates

Similarly, commenter 0207 stated that significantly more stringent standards could create 

compliance issues for the commenter’s mills if the species or condition of the wood pulped at the 

mills were to change. The commenter contended that EPA’s proposal had not accounted for such 

long-term variability and uncertainty in mills’ collection efficiencies. The commenter noted that, 

by design, their condensate collection systems generally achieve “over-collection” of HAPs in 

order to maintain compliance under varying operating conditions. The commenter argued that 

EPA’s proposal to raise the bar of compliance simply because some facilities have built a margin 

of compliance was not justified.

Response: It was not our intent to propose an increase the condensate collection 

requirements. Rather, we intended to reflect advances in condensate treatment efficiency with 

our revisions to the condensate standards. We updated our equivalency calculation for the 

treatment limits as part of our reanalysis of the condensate performance levels. Table 6 below 

lists the percent removal treatment regulatory options and their equivalents in lb/ODTP and 

ppmw considered for promulgation. The treatment standards considered for promulgation did not 

exceed the collection requirements. As noted elsewhere, EPA has decided not to promulgate 

revisions to the kraft condensate standards.

Table 6. Kraft Condensate Treatment Standards Considered for Promulgation

Percent removal 

option

lb/ODTP removalappmwb

Unbleached Bleached Unbleached Bleached

92% (baseline) 6.6 10.2 210 330

93% 6.7 10.3 184 289

94% 6.8 10.4 158 248
91

a. The equivalent lb/ODTP removal standards were calculated as follows: 0.93 x 7.2 = 6.7; 0.93 x 11.1 = 10.3; 0.94 

x 7.2 = 6.8; 0.94 x 11.1 = 10.4.

b. The equivalent ppmw standards were developed by first back-calculating an uncontrolled ppmw, U [210 ppmw = 

(1-0.92)U  U=2625 ppmw], and then applying the revised percent reduction to U [(1-0.93) 2625 = 184 ppmw].

71. Comment: ICR Data Inappropriately Interpreted. Commenters 0162 and 0163.2 included 

NCASI’s interim comment. They stated that EPA staff suggested informally, during a meeting 

with industry representatives on January 12, 2012, that the mass HAP reduction standard 

proposed in the rulemaking could also be justified by ICR data. The commenters asserted that 

this was inconsistent with rule language in the proposal, which suggested that the proposed 

numerical limits were based on a supposed equivalency between a 94 percent removal rate and a 

lb/ODTP mass reduction (see 76 FR 81345). The commenters stated that they did not have 

anything in writing from EPA explaining the basis for the proposed mass removal rate 

requirements, which prevented the industry from commenting effectively on the December 27, 

2011 proposed rule. Nevertheless, the commenters noted that EPA had suggested in subsequent 

discussions that information reported by mills in response to the Part I ICR supported the 

proposed rule. NCASI had attempted to analyze the ICR data to help EPA understand its 

significance. The commenter noted that during the January 12 meeting with industry

representatives, EPA also provided a spreadsheet summarizing the data EPA had culled from 

industry responses to the Part I ICR.

Since that meeting, NCASI was able to access the entire set of responses EPA received to 

the Part I ICR. In response to EPA’s proposal to increase assumed stripper (or biotreatment) 

efficiency from 92 to 94 percent, NCASI has determined that the ICR data are not sufficient to 

support that proposal (or any increase in treatment efficiency above the current MACT 

standards). With respect to lb/ODTP condensate treatment levels, NCASI has analyzed the ICR 

responses to assess whether they could be used to support a conclusion that technology

improvements would allow for more stringent condensate treatment requirements.

In its review, EPA subcategorized kraft mills based on the type of treatment performance 

data provided in the ICR. Specifically, EPA reviewed the mass treatment levels (lb/ODTP) 

reported by both unbleached and bleached mills to ascertain whether operational improvements 

had been realized by facilities. As discussed in the meeting with AF&PA and NCASI on January

12, 2012, several other factors need to be considered while reviewing condensate treatment 

performance data reported in the ICR and attributing that data to technological or operational 

improvements. These other factors are provided below:

 Facilities using the CCA - For facilities complying with the HVLC system requirements 

under §63.443 using CCA (§63.447) or other “equivalency by permit” options, the 

reported condensate treatment levels reflect compliance with the requirements under both 

§§63.446 and 63.447 (Phase 1 and Phase 2, respectively). Therefore, as indicated by EPA 

in the meeting, it is inappropriate to attribute the combined treatment values to Phase 1 

treatment requirements. (An example CCA compliance option was discussed in 

Attachment 6 to comment 0162.)

 High performance biological treatment systems – A handful of facilities demonstrate 

compliance with Phase 1 by treating hardpiped condensates in high-rate biotreatment 

systems like activated sludge treatment (AST), anaerobic treatment, or UNOX. These 
92

dedicated high rate systems can operate at higher treatment efficiencies than traditional 

ASBs. As a consequence, these systems are generally paired with lower lb/ODTP 

collection levels (closer to the 11.1 lb/ODTP collection requirement for bleached mills). 

The focus in these systems is to collect higher-concentration (lower-volume) condensates 

and to minimize flow (which is a significant determinant in system capital and operating 

costs). The trade-off is higher treatment efficiency on a smaller (more-concentrated and 

lower-volume) amount of HAP for roughly equivalent lb/ton-treated performance.

When percent treatment data from these systems are combined with those of ASBs and 

the “combined average” is compared against the current 92 percent standard, there is a potential 

to erroneously conclude that ASBs are performing at levels above the current standard.

 Operational and seasonal variability in biological treatment system performance –

Facilities have the option of collecting additional condensates in their hardpiping system 

in order to maintain compliance flexibility, i.e., to be able to demonstrate compliance 

using either the “percent removal” or “lb/ODTP” treatment options. Additionally, 

reported treatment levels also reflect safety margins required to demonstrate ongoing 

compliance with treatment requirements over the wide range of operational situations that 

exist throughout typical pulp mills.

 Facilities demonstrating compliance using steam strippers – The reported percent 

destruction OR percent removal numbers reflect equipment performance during one or 

two initial performance tests (IPTs). These datasets are snapshots of performance 

immediately following commissioning or scheduled maintenance and reflect safety 

factors inherent in equipment design. These design factors are essential to ensure ongoing 

compliance at the level of the current standard. They compensate for the gradual 

degradation of performance from the higher initial level of control to the minimum 

control requirement over normal maintenance cycles, largely attributable to fouling or 

scaling of heat transfer surfaces in contact with process condensates. Initial performance 

tests would, by nature, capture the high end of designed performance.

From the data requested in the ICR, it would not be possible for EPA to discern the 

relative importance and contributions of these factors, particularly in the context of the wide 

flexibility in compliance options, the design variations, and operational differences that exist 

among individual compliance systems. Recognizing this, companies responding to the ICR had 

requested that EPA confer with them in analyzing the data in order to ensure that conclusions 

reflected a thorough understanding of process variations and realities. The EPA chose not to 

communicate on these issues in developing the proposed standards.

The ICR data provided by EPA was analyzed by NCASI in order to further illustrate the 

points reiterated above. NCASI drew the following conclusions from their analysis:109

 Mills reporting percent removal in biotreatment systems

 

109 These conclusions (and the ones for unbleached mills and steam strippers below) address performance data as it 

pertains to condensate treatment. More detailed comments on the inherent variability in condensate collection levels, 

and compliance strategies used to accommodate the same, are provided in Section IV.C3 of comment 0162.
93

o Only 4 mills have reported percent removals in biotreatment systems that (a) are 

representative of Phase 1 compliance and (b) can be compared against the current 

requirement of 92 percent. This is too limited a list from which to draw substantive 

conclusions on over-performance.

o Additionally, the percent removal data do not indicate control levels in excess of 

current requirements (when compared against the actual Fbio, methanol of 94 percent).110

o Information from such a limited list of mills is not an adequate basis for revising the 

current percent removal standards.

 Unbleached mills reporting mass treatment levels (lb/ODTP)

o Only 3 facilities remain on the list with reported lb/ODTP treatment levels reflective 

of Phase 1 compliance. Data from such a limited number of facilities is not an 

adequate basis for revising the numerical condensate treatment standards.

 Bleached mills reporting mass treatment levels (lb/ODTP)

o For facilities employing steam strippers, reported treatment levels reflect equipment 

performance during one or two IPTs. These datasets reflect performance immediately

following commissioning or scheduled maintenance and reflect safety factors 

inherent in equipment design. These factors are incorporated during equipment design 

and are essential to ensure ongoing compliance at the level of the current standard 

(i.e., 92 percent).

o Given the limited number of mills remaining on this list, it is inappropriate to use 

treatment information available from these mills as the basis to revise the condensate 

treatment standards.

The details of this analysis are included in Attachment 4 to comment 0162.

Response: Our analysis of the kraft condensate standards at proposal was documented in 

a memorandum, “Summary of Kraft Condensate Control Technology Review” (EPA-HQ-OAR2007-0544-0128). The EPA did not discuss consideration of revisions to the kraft condensate 

standards with industry representatives prior to proposal, in part because we believed that only a 

marginal change in treatment efficiency was being proposed, and also because of time limitations 

for development of the proposal.111 Discussions with industry representatives ensued shortly

after the proposal was published in the Federal Register on December 27, 2011 when industry

representatives began expressing their concerns with the proposal. The EPA met with industry

representatives to discuss the kraft condensate standards on January 12, March 16, March 28 and 

May 2, 2012. Minutes for these meetings were placed in the docket soon after each meeting 

occurred.

112 In response to the commenters’ request for additional information on EPA’s 

 

110 The need to demonstrate “treatment equivalency” for non-methanol HAPs means that in order to demonstrate an 

effective methanol treatment efficiency of 92 percent (Fbio, adjusted), the actual methanol treatment efficiency (Fbio, 

methanol) would have to be at 94 percent. Details provided in Attachment 4 to comment 0162.

111 To address a lawsuit filed by Sierra Club, the subpart S RTR package was scheduled to be signed by the 

Administrator for proposal by December 15, 2011.

112 See U.S. EPA documents, titled Meeting notes for the January 12, 2012 meeting with AF&PA; Meeting notes for 

the March 16, 2012 meeting with AF&PA; Meeting notes for the March 28, 2012 meeting with AF&PA; and 

Meeting notes for the May 2, 2012 meeting with AF&PA, in the docket for the subpart S rulemaking.
94

analysis, EPA provided a spreadsheet showing the data EPA used in developing the proposed 

revisions to the condensate limits on January 12, 2012. The condensate treatment technology

performance levels used in our final analysis for promulgation are also included in the docket.113

Our reanalysis of the kraft condensate standards considered the following:

 Regulatory options for 93 and 94 percent HAP removal (as compared to the baseline of 

92 percent);

 No change in the condensate collection requirements, and clarified through revised 

lb/ODTP and ppmw treatment limits;

 Variability in treatment system performance; and

 Potential impacts on 34 of 38 CCA mills using CCA approaches involving process water 

of condensate HAP concentrations.

We acknowledge the commenters’ summary of Phase 1 and Phase 2 treatment levels, and 

note that this is an issue for mills using the CCA. We took another look at the survey data for 

CCA mills (independent of the comments received) and included costs and impact estimates for 

mills where we believed the CCA approach could potentially be negated by the revised 

condensate standards. We also considered costs to repeat the CCA demonstration in the impacts 

analysis for promulgation. 

We reviewed the performance data from the Part I ICR for biotreatment systems by

coupling the data reported in the ICR Kraft Condensates table with data reported in the ICR 

Wastewater table in order to evaluate which mills might be affected by the different condensate 

regulatory options under consideration. In the Wastewater table, mills provided quarterly results 

for the fraction of methanol removed (FbioMeOH), total HAP percent removal, and total HAP mass 

removal in kilograms per megagram of oven-dried pulp (kg/Mg ODP). Compliance is based on 

the total HAP percent removal or total HAP mass removal, which we converted to lb/ODTP for 

comparison with the regulatory options. Although commenters suggested that AST and UNOX 

systems typically have higher treatment efficiencies than ASBs, we noted overlap in the FbioMeOH

values reported in the ICR Wastewater table for all three system types, likely due to normal 

variability in biotreatment system performance.114 We also note that the cost to upgrade an ASB 

to AST is in the $30 to 35 million range for a single system,115 and UNOX systems would be 

“replacement” biotreatment systems (i.e., upgrade from an ASB is not feasible). Therefore, a 

change in biotreatment system type was not found to be cost-effective (or feasible) for the 

incremental change in the kraft condensate standards. Rather, we expect that mills would install a 

steam stripper for condensate control if their existing biotreatment system could not consistently

achieve the regulatory options due to variability.

Regarding steam stripper variability, we acknowledge that some of the data reported in 

the ICR and used to asses steam stripper performance was IPT data. However, many ICR 

 

113 See memorandum from T. Holloway, K. Hanks, and C. Gooden, RTI, to J. Bradfield and B. Schrock, EPA, titled 

Costs, Environmental, and Energy Impacts for the Promulgated Subpart S Risk and Technology Review, May 15, 

2012, in the docket for the subpart S rulemaking.

114 Id, Appendix A3.

115 See U.S. EPA document, titled Meeting notes for the May 2, 2012 meeting with AF&PA, in the docket for the 

subpart S rulemaking
95

respondents provided more recent repeat performance test data. We considered all of the reported 

performance levels in our reanalysis.

When considering all treatment systems (biotreatment and steam strippers), we noted 

from our reanalysis of performance data that mills are, on average, operating with a margin for 

variability of about 4 percent removal, or 50 percent on a lb/ODTP basis. As noted extensively

by commenters, the reasons for operational variability vary from mill to mill, and include the 

need for condensate over-collection and/or over-treatment to ensure compliance with the 

lb/ODTP treatment standard or CCA; or over-treatment to ensure compliance with the percent 

reduction or ppmw standard. Operational variability was factored into our reanalysis of the costs 

and impacts of the revised condensate treatment standards. After accounting for variability and 

other comments related to the impacts analysis (e.g., the need to account for steam stripper 

energy impacts), we found that the 93 and 94 percent removal condensate treatment options 

under consideration for promulgation were not cost-effective and resulted in undesirable energy

and secondary air emissions impacts. Therefore, we have decided not to promulgate revisions to 

the kraft condensate standards.

72. Comment: Variability in Condensate Collection. Commenters 0162 and 0163.1 stated 

that the amount of methanol generated and subsequently collected in condensate streams varies 

significantly between mills. This variability is driven by process type and final product quality

(batch vs. continuous pulping, unbleached vs. bleached, bleaching sequences, and oxygen 

delignification). Studies have also shown that, for any given mill, there is significant day-to-day

variability in methanol content of condensate streams. Consequently, mills need a reasonable 

averaging time to demonstrate compliance with the collection requirements. Facilities have used 

site-specific data on variability and, in many cases, a statistical calculation methodology, to 

demonstrate the need for this averaging period. The majority of the facilities use either a 15-day

or 30-day averaging period to demonstrate compliance with these requirements.

The commenters noted that a statistical approach was outlined by NCASI, during the 

original rulemaking, to calculate the averaging periods required to demonstrate compliance. The 

methodology and factors affecting this calculation are detailed in Attachment 7 to comment 0162

(and in Attachment A to comment 0163.1). The Relative Standard Deviation (RSD) for methanol 

collection is calculated from mill-specific data. The averaging period needed to demonstrate 

compliance is calculated for the following scenario:

 Mill over-collecting condensates by 10 percent, and

 Mill demonstrating compliance with a 95 percent compliance probability.

This approach can also be extended to other compliance probabilities and over-collection 

levels. In order to address the issue from the perspective of over-collection and to illustrate its 

importance in demonstrating compliance, Table 4 below extends this analysis to include the 

following:

 Facility uses a 15-day averaging period to demonstrate compliance.

 For a given RSD, the levels of over-collection required to demonstrate compliance at 

different compliance probabilities are calculated.

 This exercise is repeated for varying RSD levels.
96

Table 7 below provides the over-collection levels to demonstrate compliance with 

lb/ODTP collection requirements (Basis: 15-day averaging period)–submitted by commenters 

0162 (Table 4) and 0163.1 (Table 1).

Table 7. Over-Collection Levels to Demonstrate Compliance with lb/ODTP Collection 

Requirements

(Submitted by Commenters 0162 and 0163.1)

RSD

Percent Compliance Probability

95% 96% 97% 98% 99%

20 9 10 11 12 14

25 12 13 14 15 18

30 15 16 17 19 22

35 17 19 20 23 27

As an example, a facility with an RSD of 30, in site-specific condensate methanol 

content, would have to do the following:

 Over-collect methanol by 22 percent to demonstrate compliance with a 99 percent 

compliance probability.

 In other words, a bleached mill would have to collect 13.5 lb/ODTP and an unbleached 

mill would have to collect 8.8 lb/ODTP in order to demonstrate compliance with 

reasonable assurance 99 percent of the time.

 In order to demonstrate compliance with a 99 percent probability, even with a 15-day

averaging period, a facility needs anywhere from 14 to 27 percent of methanol overcollection, depending on the RSD of collection data.

Table 8 below provides a snapshot of daily variability in methanol content in condensates 

at four mills, again illustrating the need for over-collection to demonstrate compliance with high 

percent compliance probabilities, at the level required by the current standard.

Table 8. Condensate Collection Characteristics at Four Kraft Mills

(Submitted by Commenters 0162 and 0163.1)

Source

Condensate Collection Characteristics

Avg. Daily 

Collection, lb/ODTP

Standard Deviation 

(SD) RSD

Mill A (Bleached) 12.7 3.2 25.1

Mill B (Unbleached) 9.5 3.1 32.5

Mill C (Bleached) 15.1 3.4 22.4

Mill D (Bleached) 17.7 4.4 25.0

Given (a) the above discussed variability in methanol collection and (b) the requirement 

to demonstrate compliance at all times, the above analysis illustrates the following:

 Over-collection is an essential part of the compliance strategy used by mills.

 Over-collection levels and averaging times serve to increase compliance certainty with 

the condensate collection requirements.
97

 Therefore, numerical average data on collection levels that exceed currently promulgated 

levels (11.1 lb/ODTP and 7.2 lb/ODTP for bleached and unbleached mills, respectively) 

should not be interpreted as performance at levels exceeding the current standard.

Response: The EPA has evaluated the comment data provided on variability, as well as 

the rule’s current approach to averaging times for condensate collection. We have also 

reanalyzed the impact of process and treatment system variability in our regulatory analyses for 

the final rule. When accounting for variability, we have determined that a greater number of 

mills would be impacted by the proposed kraft condensate revisions than was estimated at 

proposal. We have also estimated that several of these mills would require installation of a new 

steam stripper to achieve the increase in treatment efficiency proposed. New steam strippers 

would require significant additional energy to operate (i.e., steam produced from an onsite 

boiler), and, therefore, have energy and secondary air emission impacts not considered at 

proposal. Based upon our reanalysis of the cost, energy, and secondary air emission impacts of 

the regulatory options considered for promulgation we have decided not to revise the kraft 

condensate standards.

73. Comment: Commenter 0162 stated that the proposed increase to the condensate 

treatment standard inappropriately fails to address the need to account for treatment system 

variability in both biological treatment systems and steam strippers.

Biological Treatment System Variability. Commenter 0162 explained that during the 

original development of the standards, four HAPs were identified in pulping condensates: 

methanol, propionaldehyde, acetaldehyde, and MEK (the latter is no longer a HAP, by definition, 

but is still included in subpart S). For the HAPs other than methanol, technology did not exist to 

measure concentrations below 1 ppm. Given that the concentration of these three non-methanol 

compounds is typically below 1 ppm in ASBs, there were uncertainties in quantifying and 

estimating the biotreatment efficiencies for these compounds during the timeframe of the original 

rulemaking. Facilities were, therefore, given the following option to demonstrate “treatment 

equivalency” for non-methanol HAPs:

 As a worst case, assume 0 percent treatment efficiency for non-methanol HAPs in 

biotreatment systems.

 In lieu of treating these non-methanol HAPs, demonstrate equivalency by treating an 

additional quantity of methanol equivalent to the amount of non-methanol HAPs.

The commenter explained that the industry agreed to the development of an “r-factor”–

the mass ratio of non-methanol HAPs to methanol HAPs—as a means to establishing this 

treatment equivalency. More details on the r-factor approach were provided as part of the NCASI 

Interim comments (Attachment 4 to comment 0162). When using a nominal average “r-factor” of 

0.02 (based on NCASI studies), this treatment equivalency demonstration means that the actual 

Fbio, methanol has to be 94 percent in order to achieve an adjusted Fbio of 92 percent. This 

compliance aspect was essentially written into the rule and is not an option. Therefore, ASBs, as 

currently regulated, have to operate at a higher standard with respect to methanol removal than 

strippers.
98

NCASI reviewed the reported treatment efficiencies in the ICR responses. A compilation 

of data on “intra-facility” variability in ASB performance, extracted from the 2011 pulp and 

paper ICR, was provided as part of interim comments submitted by NCASI (Attachment 4 to 

comment 0162). The average “intra-facility” variability in Fbio, methanol was about 5 percent 

according to these data. The commenter stated that, if mills are required to increase treatment of 

all HAPs from 92 to 94 percent, the actual methanol removal efficiency would now have to be 96 

percent, which is an unrealistic mandate after accounting for operational variability of 5 percent.

The commenter charged that EPA had not performed an analysis on whether this level of 

ongoing control was feasible, and it was unclear whether upgrades to systems would even be 

feasible or effective if implemented.

Steam Stripper Variability. Commenter 0162 explained that steam strippers used for 

subpart S compliance were designed and sized based on the collection and treatment 

requirements. These units are maintained to stay above the required treatment levels for 

compliance margin purposes (based on surrogate parameters). The commenter noted that 

reported efficiencies for steam strippers are generally based on the 3-run initial performance test 

(conducted when units were new or after maintenance, which represents an optimized 

performance level of the unit and not a sustained performance level). The results reported are 

expected, as the unit should perform at or near the peak of system design during the performance 

test, as this is generally when the unit is “clean” and operating at its highest efficiency and not 

representative of the minimum efficiency the unit can sustain between maintenance 

outages/cleanings. While the units can have higher “peak” efficiencies, most were designed to 

achieve a continuous treatment efficiency of 92 percent. If the performance tests results were not 

over 92 percent with a good margin of safety, a facility could not have confidence that the unit 

would be able to continuously meet the treatment standards.

Response: With regard to biotreatment system variability, we reviewed the site-specific 

r-factor values reported in the ICR and agree that this mass ratio of non-methanol HAPs to 

methanol HAPs is typically around 0.02, reflecting that approximately 2 percent of the measured 

HAP are non-methanol HAP. The maximum value of “r” reported in the ICR responses was 

0.06, and the average was 0.017. Since MEK is no longer a HAP, we considered whether to 

remove it from the group of HAPs to be included in the r-factor, but decided that MEK’s small 

contribution to “r” has little effect on the compliance calculation, and, therefore, did not amend 

the equation. We agree with the commenter’s assessment of the r-factor’s impact (i.e., that it can 

lead mills to operate their biotreatment systems to remove 96 percent methanol in order to 

compensate for the non-methanol HAP). We also independently reviewed the average “intrafacility” variability in Fbio, methanol reporting in the ICR results and noted an average Fbio, methanol

variability of 4 percent.116

Regarding steam stripper variability, we acknowledge that some of the data reported in 

the ICR and used to asses steam stripper performance was IPT data. However, many ICR 

respondents provided more recent repeat performance test data. We considered all of the reported 

performance levels in our reanalysis.

 

116 See memorandum from T. Holloway, K. Hanks, and C. Gooden, RTI, to J. Bradfield and B. Schrock, EPA, titled 

Costs, Environmental, and Energy Impacts for the Promulgated Subpart S Risk and Technology Review, Appendix 

A3, May 15, 2012, in the docket for the subpart S rulemaking.
99

When considering all treatment systems (biotreatment and steam strippers), we noted 

from our reanalysis of performance data that mills are, on average, operating with a margin for 

variability of about 4 percent removal, or 50 percent on a lb/ODTP basis. As noted extensively

by commenters, the reasons for operational variability vary from mill to mill, and include the 

need for condensate over-collection and/or over-treatment to ensure compliance with the 

lb/ODTP treatment standard or CCA; or over-treatment to ensure compliance with the percent 

reduction or ppmw standard. Operational variability was factored into our reanalysis of the costs 

and impacts of the revised condensate treatment standards. After accounting for variability and 

other comments related to our impacts analysis (e.g., the need to account for steam stripper 

energy impacts), we found that the 93 and 94 percent removal condensate treatment options 

under consideration for promulgation were not cost-effective and resulted in undesirable energy

and secondary air emissions impacts. Therefore, we have decided not to promulgate revisions to 

the kraft condensate standards.

74. Comment: Need for Flexibility. Commenter 0162 described the ongoing need for 

flexibility. The commenter contended that implementation of MACT was successful in reducing 

emissions and health risks from the pulp and paper subpart S subcategory, and that this success 

was partly due to the flexibility of compliance alternatives. There are currently three collection 

and four treatment compliance approaches along with the CCA and “equivalency-by-permit” 

options. Every mill is different in its approach to achieve compliance with the standard. These 

differences include:

 The quantity and quality of the condensates generated at the mill,

 The compliance approach for MACT I Phase 2 (collect HVLC streams or use the CCA 

option),

 The control devices and options used to achieve the treatment standards (dual treatment 

systems, over-collection of condensates to compensate for lower treatment efficiencies, 

etc.), and

 Pulping technology options (e.g., continuous and batch digesters), heat balances,

sulfidity, equipment arrangements, ambient conditions, space limitations, receiving water 

constraints, water supply limitations.

The commenter stressed that ongoing flexibility was imperative to ensure that mills can 

maintain compliance (minimize emissions and residual risk) and manage energy use while 

staying competitive in a global marketplace. The proposal to raise the treatment standard from 

92 percent to 94 percent jeopardizes compliance for facilities that designed their collection and 

treatment systems to achieve compliance with the current standard. The proposed treatment 

standards of 12.8/8.3 lb/ODTP (bleached/unbleached) threaten to negate the lb/ODTP treatment 

compliance approach, as well as the CCA and equivalency by permit (EBP)117 MACT I, Phase 2 

compliance alternatives. While the rule offers other options for collection and treatment, mills 

cannot easily convert compliance approaches without significant costs. The industry spent over 

$1 billion to achieve compliance with the pulp and paper MACT standards, and the end result 

was an acceptable level of residual risk. It is not reasonable and is legally unwarranted to make 

changes to the standards that have significant financial impacts and remove flexibility, when 

 

117 Under §63.94, a facility can propose an alternative compliance approach that would be equivalent (plus other 

benefits) to compliance with the standard. It is similar to the CCA in that it offers flexibility, but it allows the facility

to determine the approach. For example, a facility could decide to control the vents of the Black Liquor Oxidation 

System (BLOx) as part of the EBP approach.
100

there is acceptable residual risk and minimal benefit to the environment from further tightening 

the standards. The EPA failed to make an adequate demonstration in its analysis and record for 

changes of this magnitude, and, thus, current requirements should be retained.

Response: We acknowledge the site-specific nature of mills’ subpart S compliance 

strategies and expenditures (in terms of capital and engineering time) that have accompanied 

MACT compliance. In our reanalysis of the survey data, we reviewed the performance levels of 

each mill using the various percent reduction and equivalent lb/ODTP and ppmw options (for 

bleached vs. unbleached mills). We further considered the impact of revisions to the condensate 

standards on CCA mills as part of our independent reanalysis of the kraft condensate regulatory

options. Of the 38 CCA mills, we estimated that the CCA compliance approach could potentially 

be negated by the condensate standard revisions at 11 mills, and that these mills would switch 

from the CCA to use HVLC controls. Switching from CCA to HVLC control was estimated to 

cost $15 million in capital and $1.89 million/year per mill. We also estimated that 34 of the 38 

mills would be required to repeat their CCA compliance demonstration, at a cost of $130,000 per 

mill.118 Consideration of these costs, and the fact that mills are required to achieve greater HAP 

emission reduction through CCA than would have been achieved through compliance with the 

HVLC pulping vent gas standards, contributed to our decision not to promulgate the proposed 

revisions to the kraft condensate standards under the section 112(d)(6) technology review. The 

number of available condensate compliance approaches under subpart S has not changed as 

result of our final technology review.

75. Comment: Commenter 0163 submitted a copy (0163.1) of an NCASI document entitled, 

“Demonstrating Compliance with Methanol Collection and Treatment Under Subpart S –

Implementation Aspects.” The document notes that demonstrating compliance with both 

collection and treatment requirements is a two-step procedure: 

1. Demonstrating the 11.1 lb/ODTP and 7.2 lb/ODTP collection requirement, and

2. Demonstrating either the 92 percent removal OR the corresponding lb/ODTP removal 

requirement.

The document addresses the inherent variability in the amount of methanol collected in 

condensates and, when combined with operational variability in control efficiencies of the 

treatment device, highlights the importance of over-collection and compliance flexibility for 

demonstrating continuous compliance under the requirements of the current standard 

(compliance at all times or equivalent to a 99 percent+ compliance probability).

Elements of this document were also submitted with comment 0162 and are summarized 

above. The document refers to NCASI’s February 18, 2012 interim comments and includes an 

attachment entitled “Establishing Averaging Periods for Condensate HAP Collection” prepared 

by NCASI (the same document as Attachment 7 to comment 0162 noted above). 

Response: We acknowledge submittal of the NCASI document, “Demonstrating 

Compliance with Methanol Collection and Treatment Under Subpart S – Implementation 

Aspects”, and its attachments. The information in this document was reviewed and taken into 

 

118 See memorandum from T. Holloway, K. Hanks, and C. Gooden, RTI, to J. Bradfield and B. Schrock, EPA, titled 

Costs, Environmental, and Energy Impacts for the Promulgated Subpart S Risk and Technology Review, May 15, 

2012, in the docket for the subpart S rulemaking.
101

consideration in our reanalysis of the kraft condensate performance levels. As noted above, EPA 

has decided not to revise the kraft condensate standards upon further consideration of the 

operational and performance variability inherent in condensate collection and treatment systems 

and the costs, energy, and secondary air emission impacts associated with the 93 and 94 percent 

removal options analyzed for promulgation.

76. Comment: Commenter 0162 stated that the proposed concentration limit for condensate 

treatment for bleached mills was inconsistent with background documents. The commenter 

stated that, in the preamble to the proposed rule (76 FR 81345) and EPA’s memo dated October 

23, 2011, Table 2 states that the equivalent concentration for bleached mills is 248 ppmw.119

However, in the proposed rule, the concentration is listed as 210 ppmw.120 The commenter noted 

that the proposed rule needed to be modified to be consistent with the analysis in the docket.

Response: We carefully reviewed the proposed rule sections noted by the commenter and

did not see the issue. The proposed revised limit for bleached mills was 248 ppmw. (The 

originally promulgated limit for unbleached mills was 210 ppmw.) As noted above, EPA has 

elected not to promulgate the proposed revisions to the kraft condensate standards. The original 

subpart S ppmw limits for kraft condensates have been retained.

 

119 See memorandum from J. Bradfield and K. Spence, EPA, to Docket EPA-HQ-OAR-2007-0544 titled Summary 

of Kraft Condensate Control Technology Review, page 7, October 23, 2011, in the docket for the subpart S 

rulemaking.

120 76 FR 81354, proposed rule §63.443(4)
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6. Unregulated Sources

77. Comment: Commenter 0218 stated that EPA unlawfully failed to set a standard to 

control all pollutants when the EPA set the initial section 112(d) standard in 1998. The 

commenter quoted text from 63 FR 18504, 18510, specifically the statements that “MACT for 

chloroform at these mills is no control” and “EPA will also determine whether it is appropriate to 

revise MACT (pursuant to CAA section 112(d)(6)) in order to control chloroform emissions at 

those mills.” The commenter noted that EPA also stated that it was deferring control of Cl2

emissions. The commenter was unclear as to whether EPA ever fulfilled its duty to set a section 

112(d) standard for Cl2. The commenter noted that EPA‘s emission dataset shows 356 tons per 

year of chloroform and 24 tpy of Cl2.

121 The commenter asserted that EPA cannot justify failing 

to set standards to control these pollutants, and must set a section 112(d) standard in this 

rulemaking to comply with sections 112(d)(1), 112(d)(2), and National Lime Ass’n.

122

Commenter 0218 pointed out that the EPA’s original standard also stated that “[t]here are 

no control requirements for pulping systems or process condensates at [Mechanical Pulping Mill, 

Secondary Fiber Pulping Mill, Non-wood Pulping Mill, and Papermaking System] mills. For 

papermaking systems, there are no control requirements.” 63 FR 18510-11. The commenter also 

noted that EPA also exempted wood yard operations (including wood piles), tall oil recovery

systems at kraft mills, emissions from weak liquor storage tanks (even though some tanks are 

controlled), and bleaching systems that use hypochlorite and non-Cl2 compounds. Id. at 18,519-

20, 18,525.

The commenter stated that for these pollutants and sources, EPA must consider and set a 

standard, based on the emission reductions achieved and now achievable, using various 

technologies, practices, processes, and input materials now available, and this standard must 

satisfy section 112(d)(2)-(3).

Response: In the initial standard in 1998, the EPA “propose[d] to authorize Bleached 

Papergrade Kraft and Soda subcategory mills under certain circumstances to submit a 

certification based on process changes in lieu of monitoring for chloroform” (63 FR 18504). This 

process change was the conversion from Cl2 bleaching to TCF or ECF bleaching, which resulted 

in a significant reduction of chloroform emissions. The EPA also stated “[w]ith respect to 

chloroform emissions from bleaching systems, EPA is closely correlating the air and water 

standards. This is because EPA is relying on the same process change technology basis to control 

both chloroform emissions to air and pollutant discharges to water. Thus, MACT to control 

chloroform for bleaching systems requires a mill either to meet the applicable baseline effluent 

limitations guidelines and standards for all pollutants being promulgated today under the CWA

or to certify that Cl2 and hypochlorite are not used in the bleaching system.” Chlorine emissions 

are controlled through the use of bleach plant scrubbers, which are required to remove 99 percent

of bleach plant HAPs, including Cl2. For both of the stated reasons, the EPA has set a standard to 

control Cl2 and chloroform. Notably, no chlorinated bleaching compound was found to cause an 

increase in chronic cancer risk at the one in a million level.

 

121 See U.S. EPA’s Residual Risk Assessment for the Pulp & Paper Source Category at 31, in the docket for the 

subpart S rulemaking.

122 See 233 F.3d at 639; 42 U.S.C. 7412(d)(1), (d)(2).
103

We disagree with the commenter that section 112(d)(6) mandates that the EPA must 

correct any deficiency in an underlying MACT standard. We believe that section 112 does not 

expressly address this issue, and the EPA has discretion in determining how to address a 

purported flaw in a promulgated standard. We intend to further investigate potentially deficient 

standards and plan to address them in a future sector rule proposed under section 112(d)(2) and 

(3).

78. Comment: Commenter 0153 stated that the EPA should amend the affected source 

definition in §63.440(b) to include all of the affected sources in the definition of CCA affected 

source at §63.447(a)(1) (i.e., Clean condensate alternative affected source means the total of all 

HAP emission points in the pulping, bleaching, causticizing, and papermaking systems 

(exclusive of HAP emissions attributable to additives to paper machines and HAP emission 

points in the LVHC system).

The commenter suggested that the EPA change the current definition found in 

§63.447(a)(1) to remove the exclusion of HAP additives from the CCA in order to allow for new 

additive technology development. The commenter stated that two mills in the RTR are currently 

controlling HAPs in papermaking using easily transferable techniques such as white water 

temperature control and careful choice of the fresh water introduction point. The commenter 

suggested that the CCA has allowed for these new technologies to be developed and either 

numerical limits and/or work practices could be established for papermaking systems.

Response: The commenter is correct; the affected source definition in §63.440(b) should 

be changed to include causticizing and papermaking systems when standards are set for those 

emission points. We intend to explore these points in a future sector rule proposed under section 

112(d)(2) and (3).

The HAP emissions from HAP-containing paper machine additives were found to be 

negligible during the promulgation of the original rule. We reexamined the issue in our review of 

the 2011 Part I survey responses and reached the same conclusion as before. Additionally, all 

facilities must currently be in compliance; therefore, we do not expect any future CCA requests 

that would warrant adjustment to the affected source definition. We agree with the commenter 

that either numerical limits and/or work practices can be established for papermaking systems; 

we plan to address this in a future sector rule proposed under section 112(d)(2) and (3).

79. Comment: Commenter 0225 stated that “ponds” are an unregulated source. Emissions 

from the ASBs are not regulated at all, even though by PTPC’s 1993 study, those are some of the 

worst fumes to come from the PTPC mill. The commenter asserted that emissions sources must 

be included.

The commenter submitted an NCASI report (comment attachment 0225.4) of a project

undertaken to estimate the emissions of compounds from the ASB at PTPC in response to 

Agreed Order #5771, Item number 3. This project combined field studies with modeling work to 

estimate the annual emissions of methanol, propionaldehyde, MEK, and TRS compounds from 

the system. The study plan for this project was communicated to the Department of Ecology on 

January 29, 2009. The NCASI report concluded that, relative to other industry wastewater 

treatment sources, the emissions estimated are on the low end of what has been measured and 
104

studied and the treatment system appears to do an excellent job of destroying these compounds 

before significant air releases occur. The estimated emission rates were 104 tpy methanol, 13 tpy

acetaldehyde, 1.4 tpy propionaldehyde, 2.6 tpy MEK, and 58 tpy TRS.

Response: Aerated stabilization basins at facilities which treat their kraft pulping process 

condensates are considered to be regulated sources. Facilities meeting §63.446(e)(2) are required 

to discharge condensate below the liquid surface of a biological treatment system and to treat the 

condensates to destroy total HAPs by 92 percent by weight, or to remove 6.6 or 10.2 lb of HAP 

per ODTP (unbleached/bleached), or to achieve a total outlet HAP concentration of 210 or 330 

ppmw or less (unbleached/bleached). The PTPC mill uses biotreatment to control kraft 

condensates, and they over-control collection and treatment for the CCA. The MEK and TRS 

emissions to which the commenter is referring are not HAP emissions, and, therefore, are outside 

the scope of the pulp and paper subpart S RTR. The reported HAP emission rates that PTPC 

provided for the ASB in their pulp and paper Part I ICR survey response are: 48.6 tpy methanol, 

9.5 tpy acetaldehyde, and 1.2 tpy propionaldehyde. Emissions estimates for the non-HAPs MEK 

and TRS were not provided. The reported HAP emission rates were estimated using the EPA 

wastewater model WATER9 for the period from January 2, 1009 to December 31, 2009, which 

is somewhat more recent than the NCASI study cited by the commenter. After the subpart S 

proposal, the mill submitted a revised acetaldehyde emission rate of 6.3 tpy for the ASB, which 

was estimated using WATER9, but based on more recent mill data from 2010 and 2011 that 

accounted for process improvements.
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7. Startup, Shutdown, and Malfunction

7.1 Authority for Removal of the SSM Exemption

80. Comment: Commenter 0218 offered their support of the removal of certain startup, 

shutdown, and malfunction exemptions, stating that all such exemptions are unlawful and must 

be removed.

Response: We acknowledge this comment and that the commenter for their support.

81. Comment: Commenter 0225 stated that SSM plans are worthless without 

implementation. The commenter cited an incident where, in 2009, PTPC was required to present 

a plan for estimating emissions from the unregulated ASB/settling ponds. PTPC presented a 

plan, but the ponds' emissions remain unregulated. Startup-shutdown creates some of the worst 

emissions from the PTPC mill. One of the units is said to cycle two times daily to save energy. 

That's a laudable goal, but the rules were designed for a few times annually. If the pollution 

increase from shutdown-startup is worse in terms of pollution than the benefit of saving energy, 

then nothing is gained except fuel savings.

Response: We acknowledge the commenter’s concern regarding SSM plans; however, 

facilities will be required to meet the standard at all times, including during periods of startup 

and shutdown. Consequently, SSM plans are no longer required. The emissions from the 

ASB/settling ponds are regulated through the subpart S kraft condensates standards as discussed 

in section 6. 

Regarding the comment that “[o]ne of the units is said to cycle two times daily to save 

energy,” we are not sure what equipment the commenter is referring to, as there are numerous 

different types of equipment operated at pulp and paper mills. If the commenter is referring to an 

emission unit subject to subpart S, then that equipment is required to meet the current standards 

at all times. If it does not, it must record an exceedence.

82. Comment: EPA’s Regulatory Authority. Commenters 0162 and 0172 argued that EPA 

does not have authority to amend existing MACT standards to make them more stringent. The 

commenters stated that the proposed SSM provisions are changes to existing MACT standards 

that EPA promulgated previously pursuant to CAA sections 112(d)(2) and (3) for the NESHAP 

category. According to the commenters, the CAA does not contemplate EPA returning to 

previously issued MACT standards to fill “gaps” or re-determine the MACT “floors.” The 

commenters asserted that Congress instead established two distinct procedures for establishing 

standards more stringent than the original MACT standards: the 8-year review for new 

developments in practices, processes, and control technologies under CAA section 112(d)(6), 

and the review of MACT standards to determine whether more stringent limitations are 

necessary to protect human health under the CAA section 112(f)(2) “residual risk” review.

Commenter 0162 acknowledged that EPA did not invoke its section 112(d)(6) authority 

to support the proposed SSM provisions (76 FR 81328), but argued that, even if it had, section 

112(d)(6) does not provide broad authority to reconsider aspects of previously issued MACT 

standards unrelated to “developments in practices, processes, and control technologies.” The 
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commenter concluded that EPA cannot simply revisit and redo a MACT determination long after 

it has been issued, which the commenter said EPA attempted to do with the proposed SSM 

provisions. The commenter argued that EPA cannot merely change its mind about what 

standards are required to comply with CAA sections 112(d)(2) and (3), nor can it recalculate a 

MACT “floor” based on subsequent performance. Cf. NRDC v. EPA, 529 F.3d 1077, 1084 (D.C. 

Cir. 2008) (rejecting contention that CAA section 112(d)(6) requires EPA to “start from scratch” 

and develop new MACT standards).

According to commenter 0162, reassessing existing NESHAPs now, that were based on 

the MACT “floor” years ago, and imposing more stringent requirements, would be inconsistent 

not only with the statute’s careful provision of technology-review and residual-risk authority to 

follow establishment of MACT standards, but also with Congress’s desire for finality evident in 

the judicial review provisions of CAA section 307(b). The commenter noted that challenges to 

MACT standards need to be raised within 60 days of their promulgation. The commenter 

maintained that this provision ensures that regulated entities, EPA, and the public know what 

emission limitations will apply to a source, rather than having those limitations be subject to 

flux. The commenter pointed out that, in the current case, facilities regulated by the NESHAPs 

long ago made capital investment decisions and developed and honed their operating procedures 

to meet the existing MACT standards. According to the commenter, the CAA does not allow 

EPA simply to revisit the analysis and decisions involved in developing emission standards that 

meet the requirements of CAA sections 112(d)(2) and (3).

Commenter 0162 further argued that, even if EPA did have authority to go back and 

change the existing MACT standards, it would have to justify why the decisions reflected in the 

current standards are wrong and why the new standards meet the required criteria that EPA must 

satisfy in issuing MACT standards under CAA sections 112(d)(2) and (3). According to the 

commenter, EPA has not made either showing in the proposed rule. The commenter stated that 

EPA also would be required, under CAA section 112 and EO 13563, to assess the costs and 

benefits of eliminating the SSM provisions in the current subpart S standards. The commenter 

noted that EPA made no attempt to assess the costs and benefits or even identify what changes 

pulp and paper mills might make to their facilities in response to the elimination of the SSM 

provisions.

Another commenter (0164) contended that the approach EPA is taking fails to account 

adequately for emissions that occur during SSM periods. The commenter stated that EPA based

its actions on an incorrect reading of the D.C. Circuit Court’s Sierra Club v. EPA decision (551 

F.3d 1019 (D.C. Cir. 2008), cert. denied, 130 S. Ct. 1735 (2010)), and on unreasonable or 

insufficiently supported assumptions about SSM events and emissions during SSM periods. 

According to the commenter, EPA has proposed to change regulations that have been in place for 

many years and whose SSM provisions were never challenged in court, without any

demonstration that it has legal authority to do so and without any apparent factual analysis of the 

statutory criteria for standard-setting under section 112.

Commenter 0164 stated that EPA has for decades recognized, in technology-based 

standards under the CAA and other statutes, that in many cases it is not feasible with an 

identified technology to achieve the same emission limitations during SSM events as have been 

established for normal operations. Historically, EPA has, therefore, applied different 
107

requirements during SSM events. The EPA has not justified departing from that practice in the 

proposed rule. The EPA has also not made any attempt to demonstrate that the amended 

standards it proposed reflect the performance actually achieved by the best-performing existing 

sources that formed the basis for the current subpart S standards or, alternatively, that they meet 

the statutory criteria for establishing beyond-the-floor MACT standards.

Commenter 0164 pointed out that the provisions in the current subpart S regulations that 

exempt emissions during SSM events from compliance with numerical emission limitations 

derived for normal operations, or that limit the duration of SSM events that result in emissions

higher than the emission limitation for normal operations, were developed by EPA based on the 

performance of facilities identified as the “best performers” when EPA promulgated the current 

subpart S standards. The EPA cannot now simply disavow its conclusion that even “best 

performers” will exceed the emission standards established for normal operations during SSM 

events.

Response: From Mineral Wool/Wool Fiberglass comment p. 23 draft response At 

proposal, we explained that the D.C. Court had recently vacated the SSM exemption contained in 

§§63.6(f)(1) and 63.6(h)(1) that are part of the section 112 regulations commonly referred to as 

the GP rule. Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008) cert. denied, 130 S. Ct 1735 

(2010). We further explained that, when incorporated into section 112(d) regulations for specific 

source categories, these two provisions exempt sources from the requirement to comply with 

otherwise applicable MACT standards during periods of SSM. We also explained that because 

the pulp and paper NESHAP relies on the GP rule for SSM provisions, we were proposing to set 

standards that apply during startup and shutdown periods for this source category. (76 FR 81345-

81346). The EPA does not claim that the Sierra Club case constrains its authority to prescribe 

unique standards for SSM periods. Rather, EPA’s view is that this decision calls into question 

the legality of source category-specific SSM exemptions in rules promulgated pursuant to section 

112. 

Based on Mineral Wool/Wool Fiberglass comment p. 24 draft response. Further, in 

Medical Waste Institute v. EPA, 645 F. 3d 420, 425-27 (D.C. Cir. 2011), the D.C. Circuit Court 

held that EPA may permissibly amend improper MACT determinations, including amendments 

to improperly promulgated floor determinations, using its authority under section 112(d)(2) and 

(3). The absence of standards for HAP emitted during SSM is not proper. National Lime, 233 F. 

3d at 633-34; see also Medical Waste Institute, 645 F. 3d at 426 (resetting MACT floor, based on 

post-compliance data, permissible when the originally-established floor was improperly

established, and permissibility of EPA’s action does not turn on whether the prior standard was 

remanded or vacated). Similarly, the D.C. Circuit Court’s December 9, 2011 decision in 

Portland Cement Ass’n v. EPA (D.C. Cir. No. 10-1358) confirms that EPA is not constrained by

section 112(d)(6), and it may reassess its standards more often, including revising existing floors 

if need be. The commenters are, thus, incorrect that section 112(d)(6) provides the exclusive 

authority to address standards that apply during SSM events. Here, EPA adopted no MACT 

standard at all for HAP emitted during SSM, an approach soundly rejected by the D.C. Circuit

Court in National Lime, 233 F. 3d at 633-34. Consequently, we have revised the standards so the 

emission limits of the rule apply at all times, including during periods of SSM.
108

Specific for P&P Contrary to the commenter 0162’s assertion that EPA ignored the costs 

of the SSM revisions, EPA’s proposal cost analysis included a one-time cost to revamp existing 

recordkeeping systems to be consistent with the proposed revisions to the startup and shutdown 

provisions, and included costs for asserting an affirmative defense. These costs were derived 

from the Paperwork Reduction Act (PRA) supporting statement developed for proposal.123,124

These costs have also been included in the final cost analysis and supporting statement for the 

subpart S final rule.

83. Comment: Consistency with Sierra Club v. EPA. Commenters 0162 and 0172 argued 

that EPA’s proposed requirement that sources must meet the same emission limitations during 

SSM is not required by case law and is inconsistent with past EPA practice and judicial 

interpretations of NESHAPs and NSPS. The commenters stated that EPA has recognized for 

decades that it is often unreasonable to require sources to meet technology-based emission 

standards, such as NSPS promulgated under CAA section 111, during SSM periods (§60.8(c)). 

The commenters contended that this understanding has been a critical piece of most MACT 

standards as well, through incorporation by reference of the NESHAP GP SSM requirements, 

inclusion of specific provisions for SSM events in the categorical MACT standards, or both. 

Despite that fact, the commenters noted that EPA proposed that the emission limitations in 

subpart S issued under CAA section 112 (which is modeled in part on section 111) would now 

be applicable at all times, even during SSM events (e.g., proposed sections 63.443 and 63.459).

Commenter 0162 rejected EPA’s suggestion that its treatment of excess emissions during 

SSM events in the proposed standards is appropriate, even “required,” in order to make the 

standards “consistent with” the D.C. Circuit Court’s decision in Sierra Club v. EPA, 551 F.3d 

1019 (D.C. Cir. 2008), cert. denied, 130 S. Ct. 1735 (2010), which vacated the exemption125 for 

excess emissions during SSM events contained in the 40 CFR Part 63, subpart A GP for 

emission standards for hazardous air pollutants under CAA section 112 (76 FR 81345). The 

commenter argued that the D.C. Circuit Court’s Sierra Club decision does not compel or even 

support EPA’s adoption of the proposed SSM provisions, based on the following reasons.

First, commenter 0162 noted that the Sierra Club decision interpreted the NESHAP GP

and did not by its terms address what EPA may or may not include in category-specific MACT 

standards. Second, the commenter noted that the Sierra Club decision did not say that the same 

emission limitations that EPA has derived for normal operations must also apply during SSM 

events, and the decision does not preclude EPA from applying different standards during SSM 

events than apply during normal operations. The commenter noted that the Sierra Club panel’s 

holding only said that “there must be continuous section 112-compliant [MACT] standards” (551 

F.3d at 1027). According to the commenter, the Sierra Club opinion noted that the definition of 

 

123 See memorandum from T. Holloway, K. Hanks, and C. Gooden, RTI, to J. Bradfield and B. Schrock, EPA, titled

Costs and Environmental and Energy Impacts for Subpart S Risk and Technology Review, November 17, 2011, in 

the docket for the subpart S rulemaking.

124 See U.S. EPA, Supporting Statement: NESHAP for Pulp and Paper Production (40 CFR Part 63, Subpart S) 

(Proposed Amendments), November 2011.

125 According to commenter 0162, while the D.C. Circuit (and EPA in the preamble to the proposed rule) referred to 

the provision vacated in the Sierra Club decision as an "exemption" from HAP standards during SSM events, in fact 

other portions of the NESHAP GP impose various requirements that apply to sources during SSM events (including 

the obligation to minimize excess emissions), and in anticipation of and following SSM events (including 

requirements to prepare a plan to address SSM events and to report SSM events).
109

“emission standard” in CAA section 302(k) includes the broad phrase “any requirement relating 

to the operation or maintenance of a source to assure continuous emission reduction,” and stated

that it suggests that EPA can establish MACT standards consistent with CAA section 112 

“without necessarily continuously applying a single standard.”126

Commenter 0162 argued that there is ample precedent for EPA applying a different 

standard during SSM events. The commenter noted that the definition of “emission limitation” 

and “emission standard” in CAA section 302, which “limits the quantity, rate, or concentration 

of emissions of air pollutants on a continuous basis”—language which the D.C. Circuit Court 

considered dispositive in interpreting EPA’s standards-setting authority under section 112—has 

been in the statute since 1977. Throughout that time, the commenter stated, EPA has not required 

sources to meet during SSM events the CAA section 111 NSPS emission limitations established 

for normal operations (§60.8(c)). The commenter pointed out that Congress had, in fact, enacted 

the continuous basis language in section 302(k) knowing that EPA’s emissions standards under 

section 111 exempted SSM periods. Commenter 0162 asserted that there is nothing in the 

legislative history of the 1977 amendments to the CAA that suggests Congress intended to 

overturn that practice.127 The commenter also pointed out that court decisions both before and 

after the CAA Amendments of 1977, some of which the commenter cited below, have affirmed 

the appropriateness of including special SSM provisions in standards issued under section 111—

despite the “continuous basis” language in the definition of “emission limitation.” Similarly, the 

commenter noted that there is nothing in the legislative history of the CAA Amendments of 1990 

that suggests Congress meant something completely different when it used the same defined 

 

126 See 551 F.3d at 1027. “Indeed, this reading is supported by the legislative history of section 302(k).” Id. See also 

id. at 1021 (“accepting that ‘continuous’ for purposes of the definition of ‘emission standards’ under CAA section 

302(k) does not mean unchanging”); id. (referring to “the CAA’s requirement that some section 112 standard apply 

continuously”) (emphasis added). Commenter 0162 stated that, since it was addressing only a generic SSM 

exemption, the Sierra Club decision did not consider whether EPA, in the context of individual categorical 

standards, could determine that it is infeasible to apply the same limits, or any limits on the mass or concentration of 

pollutants emitted at all, during SSM events, or that it would lead to absurd results to do so.

127 Commenter 0162 argued that the “continuous basis” language inserted in 1977 related to a debate in Congress 

about whether sources should be allowed to use temporary or intermittent pollution control technologies, as the D.C. 

Circuit recognized in Sierra Club v. EPA, 551 F.3d 1019, 1027 (D.C. Cir. 2008), cert. denied, 130 S. Ct. 1735 

(2010), citing Kamp v. Hernandez, 752 F.2d 1444, 1452 (9th Cir.1985). See also Conference Report on H.R. 6161 

(the CAA Amendments of 1977), H. Rep. No. 95-564 (August 3, 1977) at 129 (requirement to use “continuous 

emission controls” “clarifies that intermittent or alternative control measures are not permissible means of 

compliance”), 172; S. Rep. No. 94-717 (March 29, 1976) at 78 (definition of “emission limitation” being amended 

to clarify that “[i]ntermittent controls or dispersion techniques are unacceptable as a substitute for continuous control 

of pollutants” and contrasting intermittent controls, which vary based on predicted changes in pollutant dispersion 

due to meteorological predictions, with continuous controls such as flue-gas cleaning equipment); see also Nat’l 

Lime Ass’n v. EPA, 627 F.2d 416, 434 n.54 (D.C. Cir. 1980) (“The ‘intermittent’ controls that concerned Congress 

were any of those which entailed temporary reductions in emissions when weather conditions were poor.”). 

According to commenter 0162, the language about “continuous reduction” in the definition of “emission standard” 

did not address what emission limitations apply during SSM periods, nor EPA’s established practice of exempting 

excess emissions during SSM events from the performance standards applicable to normal operations. The 

commenter stated that, in fact, the legislative history indicates Congress was aware that alternative emission 

limitations might at times be necessary, even though the emission limitations were established based on the 

capability of “continuous controls” like scrubbers. See, e.g., S. Rep. No. 94-717 at 78 (“It is recognized that the 

source controls may not be available to achieve the full reduction required of a particular source under particular 

circumstances. In such case, supplementary programs can and should be developed. But this flexibility occurs only 

after imposition of the continuous emission limitation.”).
110

terms, “emission standard” and “emission limitation,” in directing EPA to establish MACT 

standards.

Third, commenter 0162 noted that the Sierra Club decision did not address whether EPA 

could use a “design, equipment, work practice or operational standard,” as authorized under 

CAA section 112(h) and included in the definition of “emission limitation” and “emission 

standard” in CAA section 302(k), in lieu of a numerical emission limitation during SSM events. 

The commenter further noted that EPA told the Court that the GP SSM exemption struck down 

in Sierra Club was not an alternative standard based on the work practice standard authority. See 

551 F.3d at 1028. According to the commenter, EPA argued in that case that section 112(h) was 

in fact irrelevant to its authority to exempt excess emissions during SSM events. Id. at 1030 

(Randolph, J. dissenting).

As a result, commenter 0162 stated, EPA cannot hide behind the Sierra Club decision as 

a justification for ignoring an inability of even the “best performers” to achieve during SSM 

events the emission limitations that EPA has established for normal operations. The commenter 

further stated that the approach EPA proposed would not establish the “continuous section 112-

compliant standards” that the Sierra Club decision concluded are required. See 551 F.3d at 1027. 

Commenter 0162 noted that, under CAA section 112(d)(2), MACT emission standards must be 

“achievable.” The commenter further noted that, if EPA sets the emission standards based on the 

“best performing 12 percent of units in the category” (the MACT “floor”), those limitations must 

on average be “achieved” by the best performers (CAA section 112(d)(3); Sierra Club v. EPA

(standards based on the MACT “floor” must be achievable “under the worst foreseeable 

circumstances”).

Commenter 0162 stated that an emission limitation that applies during SSM events does 

not meet the requirement of CAA section 112(d)(2) that “emission standards” under that section 

be “achievable,” if in fact EPA has not demonstrated that the limitation is “achievable” with 

available technology, “taking into consideration the cost of achieving such emission reduction, 

and any non-air quality health and environmental impacts and energy requirements.” The 

commenter similarly noted that an emission limitation that applies during SSM events has not 

been demonstrated to be “achieved” by the best-performing 12 percent of units in the category

under CAA section 112(d)(3) unless EPA can show that those best performers actually meet that 

emission limitation during SSM events. According to the commenter, the proposed rule would 

not establish “continuous section 112-compliant standards” because, as discussed below, EPA 

has not demonstrated that the emission limitations in the existing MACT standards, if they also 

applied during SSM events, would comply with section 112 when applied to SSM periods.

Commenter 0162 asserted that this plain-language reading of the applicable statutory

requirements is echoed by extensive case law. According to the commenter, the courts have long 

recognized that a “technology based standard discards its fundamental premise when it ignores 

the limits inherent in technology.” NRDC v. EPA, 859 F.2d 156, 208 (D.C. Cir. 1988). As an 

example, the commenter cited the D.C. Circuit Court decision in Portland Cement Ass'n v. 

Ruckelshaus, 486 F.2d 375, 398 (D.C. Cir. 1973), a decision reviewing standards under CAA 

section 111, which the commenter said recognized that “‘start-up’ and ‘upset’ conditions due to 

plant or emission device malfunction, is an inescapable aspect of industrial life and that 

allowance must be made for such factors in the standards that are promulgated.” Id. at 399. As a 
111

second example, the commenter cited Essex Chem. Corp. v. Ruckelshaus, 486 F.2d 427, 432 

(D.C. Cir. 1973), cert. denied, 416 U.S. 969 (1974), another section 111 case, in which the Court 

held that SSM provisions are “necessary to preserve the reasonableness of the standards as a 

whole.” Id. at 433. The commenter further cited National Lime Ass’n v. EPA, 627 F.2d 416 (D.C. 

Cir. 1980), another case reviewing emission standards promulgated under CAA section 111, in 

which the Court held that the analogous CAA requirement that NSPS be “achievable” means that 

the standards must be capable of being met “on a regular basis,” including “under most adverse 

circumstances which can reasonably be expected to recur,” including during periods of SSM. 

627 F.2d at 431 n.46.

According to commenter 0162, courts have reached a similar conclusion when 

considering the analogous CWA requirements that EPA establish technology-based effluent 

limitations based on the best available control technology. The commenter noted one such case, 

in which the 9

th Circuit Court held that, where EPA knew that there would be periods where a 

discharger, even with “exemplary use of” the identified best technology, would exceed the 

effluent limitations because of conditions “beyond the control of the permit holder,” EPA had 

violated the CWA by failing to provide an “upset provision” to address those periods. Marathon 

Oil Co. v. EPA, 564 F.2d 1253, 1273-74 (9th Cir. 1977). The commenter also cited NRDC v. 

EPA, 859 F.2d at 207, distinguishing between technology-based effluent limitations, where some 

provision for “upsets” is required, and water-quality-based effluent limitations, which are tied to 

achieving water quality standards rather than based on available technology, and, therefore, need 

not include an upset provision.128

According to commenter 0162, the 1977 CAA Amendments support the conclusion that 

emission standards need to deal with the inability of a source to meet the normal emission 

limitations during particular circumstances. The commenter further noted that the National Lime 

Ass’n decision discussed above, which relied in part on the cases EPA referenced in the 

preamble, and which directly addresses the need for emission limitations that address reasonably

anticipated adverse circumstances, post-dates the CAA Amendments of 1977 by 3 years.

According to commenter 0162, the Sierra Club decision does not prevent EPA from 

adopting emission standards for SSM periods that are different from those required during 

periods of normal operation, nor does it mean that EPA is barred from using a “requirement 

relating to the operation or maintenance of a source to assure continuous emission reduction” as 

the emission standard that applies during such events (551 F.3d at 1027). According to the 

commenter, the Sierra Club decision only rejected EPA’s assertion that it had discretion to 

 

128 According to commenter 0162, he Weyerhaeuser Co. v. Costle decision that EPA cites in the preamble to the 

proposed rule, 590 F. 2d 1011 (D.C. Cir. 1978), does not support EPA’s position (76 FR 72535). The commenter 

noted that, in that case, the court was discussing a “technology forcing” standard, rather than one, like MACT, that 

is to be based on what is already being “achieved” or has been demonstrated to be achievable. The commenter 

further noted that the SSM events that EPA acknowledges are expected to occur at sources subject to the proposed 

standards are a far cry from the “‘uncontrollable acts of third parties,’ such as strikes, sabotage, operator 

intoxication, or insanity” that the Court was considering in the passage quoted by EPA, (76 FR 7535, col. 1). The 

commenter pointed out that industry is not requesting that the MACT standards provide relief from numerical 

emission limitations during those unusual types of events. The commenter also noted that the Weyerhaeuser

decision, perhaps most importantly, came long before NRDC v. EPA, 859 F.2d 156 (D.C. Cir. 1988) which, the 

commenter noted above, affirmed the need for an upset provision to address circumstances where compliance with 

effluent limitations is impossible through no fault of the permittee, and which endorsed Marathon Oil.
112

decide not to impose any emission standard covering SSM periods (Id. at 1027-28, 1030 (noting 

that EPA was not claiming that the GP SSM exemption was either an emission standard under 

CAA section 112(d) or a design, equipment, work practice, or operational standard under section 

112(h)).129

Commenter 0162 concluded that, despite EPA’s implications to the contrary, the Sierra 

Club decision expressly recognized that different standards, including non-numerical standards, 

may (and in some cases must) apply during non-standard operating conditions, such as SSM.

Commenters 0163 and 0212 also disagreed that the court decision requires the EPA to set 

numerical emission limits for startup or shutdown periods. Commenter 0163 noted the Sierra 

Club decision [Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), cert. denied, 130 S. Ct. 1735 

(2010)] vacated the broad emission standard exemption during SSM events contained in the 

40 CFR part 63, subpart A GP. Commenter 0163 held that the court decision did not say that the 

same emission limitations that EPA has derived for normal operations must also apply during 

SSM events, and, therefore, does not preclude EPA from applying different standards during 

SSM events than standards that apply during normal operations. Commenter 0163 referred EPA 

to detailed comments on this issue on the proposed NESHAP modifications for the Mineral 

Wool and Ferroalloys industries by ad hoc SSM Coalition, to which the commenter is affiliated 

as a member of American Wood Council.

Commenter 0164 stated that applying the same emission standards even during SSM 

periods is not compelled by the statute nor by applicable case law, including the Sierra Club v. 

EPA decision. The commenter (0164) provided several options for setting MACT standards for

such periods, including establishing a design, equipment, work practice, or operational standard 

under CAA section 112(h).

Response: Based on Mineral Wool/Wool Fiberglass comment p. 25 draft response As 

explained earlier, we are setting standards that apply during startup and shutdown periods in 

response to the decision vacating pertinent provisions in the GP rule. We do not claim that the 

Sierra Club decision constrains our authority to prescribe unique standards during SSM periods. 

But there must be a basis for our determination to prescribe standards other than MACT 

standards during those events. Moreover, section 112(h) allows EPA to use work-practice 

standards instead of an emissions floor “if it is not feasible in the judgment of the Administrator 

to prescribe or enforce an emission standard.” Under section 112(h)(2)(B), it is “not feasible” to 

set an emission standard when “the application of measurement methodology to a particular class 

of sources is not practicable due to technological and economic limitations.” Thus, section 

112(h) “allows EPA to substitute work practice standards for emission floors only if measuring 

emission levels is technologically or economically infeasible.” Sierra Club v. EPA, 479 F. 2d 

875, 880 (D.C. Cir. 2007). 

 

129 According to commenter 0162, the statement in the majority opinion that “Congress gave no indication that it 

intended the application of MACT standards to vary based on different time periods,” 551 F.3d at 1028: (1) is 

contradicted by other statements in the opinion, referenced above, that a MACT standard need not continuously 

apply a single emission limitation, (2) is dicta, because that was not the situation presented by the challenged 

regulations and argued by EPA, (3) ignores the extensive case law about technology-based limitations referenced 

above, and (4) does not in any event say that the CAA precludes EPA from adopting different emission limitations 

that apply during SSM events.
113

Here, we do not have a basis to prescribe work practice standards. As discussed in detail 

in Section 7.2, we have reviewed the information available to us regarding startup and shutdown 

periods, and we believe that the expected startup and shutdown emissions (as indicated through 

the continuous compliance requirements implemented for subpart S) are not likely to cause a 

violation of the standards. We also found no evidence which suggested emissions were higher 

during startup or shutdown that would indicate a need for an alternate standard for these periods. 

The EPA is, therefore, promulgating the same standards that apply during normal operation for 

the pulp and paper industry for periods of startup and shutdown. Contrary to the commenter’s 

argument, we believe that the standards that apply during startup and shutdown periods will 

establish “continuous section 112-compliant standards” that the Sierra Club decision concluded 

are required.

Further, the relevance of Portland Cement and Essex Chem. Corp. is questionable in light 

of subsequent case law and the 1977 amendments to the CAA’s definition of emission standard,

requiring that such standards be continuous. Further, the NRDC case interprets provisions of the 

CWA that are different in nature than provisions governing standards under section 129 of the 

CAA. In any event, even if those cases are relevant, EPA‘s overall approach to malfunction 

events in this rule, including the promulgation of an affirmative defense, is consistent with the 

approach set forth in EPA‘s 1972 proposed rules cited favorably in Portland Cement and Essex 

Chemical, in that both EPA‘s approach today and in 1972 impart a construction of 

“reasonableness” to the standards as a whole and adopts a more flexible system of regulation 

than can be had by a system devoid of “give.” Portland Cement at 399. Portland Cement and 

Essex criticized EPA regulations that contained no specific provisions to address malfunctions 

and EPA’s assertion that malfunctions would be dealt with by the informal exercise of discretion 

in the Agency‘s enforcement activities. Those decisions did not require exemptions or less 

stringent standards for malfunction events as the commenter suggests. The EPA‘s approach to 

malfunctions goes further than reliance on the informal exercise of enforcement discretion, in 

that it includes regulatory provisions establishing an affirmative defense to civil penalties for 

exceedances of emission limits that are caused by malfunctions. As noted above, the NRDC v.

EPA, 859 F. 2d 156, 207 (D.C. Cir. 1988) case cited by the commenter is not on point, and the 

discussion of technology-based standards is dicta. Nevertheless, EPA‘s approach to malfunctions 

is consistent with NRDC. NRDC does not require exemptions or less stringent standards for 

malfunctions either. Further, the regulatory affirmative defense being included in the subpart S 

final rule is consistent with the case cited in the NRDC decision; Marathon Oil Co. v. EPA, 564 

F.2d 1253, 1272 (9th Cir. 1977). The court in Marathon Oil held that EPA must formalize its 

approach to upsets under the CWA. The affirmative defense does so. See, Mont. Sulphur &

Chem. Co. v. United States EPA, 2012 U.S. App. LEXIS 1056 (5th Cir. Jan 19, 2012) (in 

rejecting industry argument based on Marathon Oil that reliance on the affirmative defense was 

not adequate, the court stated “[h]owever, here the EPA does not rely on enforcement discretion 

alone, but specifically promulgates an affirmative defense in the FIP, which clearly defines the 

requirements to avoid penalties.”). But see, Weyerhaeuser v. Costle, 590 F.2d 1011, 1057-58 

(D.C. Cir. 1978) (holding that an informal approach is adequate). In fact, the affirmative defense 

comports with the court‘s suggestion in Marathon Oil that EPA place the burden on the permit 

holder of producing the relevant data and proving that the upset could not have been prevented. 

Id.
114

84. Comment: General Provisions. Commenter 0162 noted that, in the preamble on page 

81346 of the proposed rule, EPA requested comments “on whether there are any such provisions 

that we have inadvertently incorporated or overlooked” in reference to the proposed changes in 

SSM language. While the commenter disagreed with the proposed changes noted above, the 

commenter reviewed the rule and was not aware of any cases where the proposed rule was 

inconsistent with EPA’s intent.

Response: We thank the commenter for taking the time to review the GP references. We 

have made several changes to the final rule language related to SSM, including:

 Clarification that the affirmative defense provisions apply to violations of standards due 

to malfunctions, as defined in 40 CFR 63.2;

 Elimination of the 2-day notification requirement;

 Replacement of the 45-day affirmative defense reporting requirement as follows: “This 

affirmative defense report shall be included in the first periodic compliance, deviation 

report or excess emission report otherwise required after the initial occurrence of the 

violation of the relevant standard (which may be the end of any applicable averaging 

period). If such compliance, deviation report or excess emission report is due less than 

45 days after the initial occurrence of the violation, the affirmative defense report may be 

included in the second compliance, deviation report or excess emission report due after 

the initial occurrence of the violation of the relevant standard.”; and

 Elimination of the 30-day extension for submitting a written affirmative defense report.

7.2 Startup and Shutdown

85. Comment: Commenters 0162 and 0172 argued that EPA must fully justify applying the 

same emission limitations during startup and shutdown as during normal operations. The 

commenters noted that, in the preamble to the proposed rule, EPA did not say that it was 

precluded from adopting different emission limitations that would apply during startup and 

shutdown periods. According to the commenter, EPA instead stated that “[n]othing in the record 

suggests that the operations (and attendant emissions) are significantly different during startup or 

shutdown than during normal operations. Periods of startup, normal operations and shutdown are 

all predictable and routine aspects of a source’s operations” (76 FR 81346).

According to commenter 0162, this falls far short of the “reasoned analysis” that an 

agency must supply before changing a prior decision. See, e.g., Motor Vehicle Mfrs. Ass’n v. 

State Farm Mut. Auto. Ins. Co., 463 U.S. 29, 42 (1983) (“an agency changing its course by 

repealing a rule is obligated to supply a reasoned analysis for the change”); Williams Gas 

Processing-Gulf Coast Co. v. FERC, 475 F.3d 319, 326 (D.C. Cir. 2006) (“it is axiomatic that 

agency action must either be consistent with prior action or offer a reasoned basis for its 

departure from precedent”) (internal quotation marks and brackets omitted). The commenter 

noted that EPA, in promulgating the existing subpart S regulations, specifically considered the 

need for special provisions to address higher emissions occurring during startup and shutdown as 

reflected in EPA’s decision to include startup and shutdown periods in the excess emission 

provision for condensate treatment but not for LVHC and HVLC NCG controls (63 FR 18529-

30). According to the commenter, if EPA wishes to change its prior determinations with respect 

to startup and shutdown provisions, it would have to explain how it erred in arriving at those 
115

prior determinations, or how available information has changed since that time. Commenter 0162 

argued that the cursory treatment of this issue in the preamble to the proposed rule is not 

sufficient justification for reversing EPA’s prior determinations with respect to startups and 

shutdowns. The commenter indicated that there is no indication that EPA has analyzed sufficient 

data on emissions during startup and shutdown to justify its conclusion, as opposed to merely 

assuming it is correct. According to the commenter, EPA cannot conclude that special provisions 

for emissions during startup and shutdown are not needed based on “mere speculation.” See 

NRDC v. EPA, 859 F.2d 156, 210 (D.C. Cir. 1988). The commenter argued that the default 

assumption must be that they are needed. The commenter noted that EPA, in establishing the 

existing subpart S standards, previously determined that the best performers on which the MACT 

standards were based may not achieve those standards during startup and shutdown. The 

commenter asserted that EPA cannot simply change its mind about this sort of assessment 

without providing a factual analysis supporting EPA’s new conclusion that MACT standards can 

be achieved during all startup and shutdown periods as well. See, e.g., Transactive Corp. v. 

United States, 91 F.3d 232, 237 (D.C. Cir. 1996). The commenter doubted that emissions data 

representative of startup and shutdown events exist that would be sufficient for EPA to conduct a 

reasoned analysis to demonstrate the achievability of the MACT emission limits established for 

normal operations during startup and shutdown events (contrary to EPA’s prior rulemaking), 

because of likely limitations in the available data.

According to commenter 0162, there are several reasons why adequate data often do not 

exist to allow EPA to conclude that an emission limitation established for normal operations also 

represents the performance of the best demonstrated control technology during startups and 

shutdowns. First, to the extent that emissions data come from required performance tests, the 

commenter noted that applicable regulations generally prohibit testing during SSM conditions, 

and require that data not be used for compliance purposes if obtained during a startup, shutdown, 

or malfunction event.130 Second, to the extent that EPA evaluates emissions data collected 

through continuous monitoring, the commenter noted that applicable regulations often require or 

allow the source to exclude from its reporting of continuous monitoring data those data reflecting 

SSM conditions. Finally, the commenter noted that atypical pollutant concentrations and other 

stack conditions that may exist during startup and shutdown can result in the continuous 

monitoring system producing unusable data because the pollutant concentration may be outside 

of the monitoring equipment’s span or the stack conditions may not meet monitoring system 

quality assurance/quality control (QA/QC) parameters, or the data may be truncated on the high 

end because of limitations of the monitoring equipment.131

Commenter 0162 concluded these factors would cause EPA to understate emissions 

occurring during startup and shutdown. The commenter also cited an additional problem—that it 

can be unclear whether a condition that leads to excess emissions should be characterized as a 

startup or shutdown event or a malfunction event. According to the commenter, without a clear 

demarcation (both in EPA regulations and in practice), EPA could be analyzing data sets that 

 

130 Commenter 0162 cited as an example the NESHAP GP, specifically the statement that performance tests can 

only be conducted under representative conditions and which specify that: “Operations during periods of startup, 

shutdown, and malfunction shall not constitute representative conditions for the purpose of a performance test....” 

40 CFR 63.7(e)(1); see also 40 CFR 60.8(c) (same for performance testing for NSPS).

131 Commenter 0162 noted that data from periods when the monitoring system is outside of control limits are 

required to be excluded from emission averages under the NESHAPs General Provisions. See 40 CFR 63.8(c)(7)(ii).
116

exclude events that were treated as malfunctions, but that EPA would say should be included in 

calculating average performance as startup or shutdown conditions.

According to commenter 0162, while EPA may not be able to calculate average HAP 

emissions during startup and shutdown periods, EPA certainly has available to it information that 

indicates that pulp and paper mills using the MACT “floor” technologies and complying with the 

subpart S standards during normal operations would not be able to comply during at least some 

startup and shutdown conditions. As an example, the commenter cited the requirement in 

§63.443(c) that emissions from specific processes be vented into a closed-vent system and routed 

to a control device. According to the commenter, because these gases can be explosive, they

cannot be routed to an incineration device unless the concentration and volume of the vent gas 

and the conditions in the incineration device meet certain conditions necessary to prevent 

explosions (“permissives”). The commenter noted that when pulping processes are starting up or 

shutting down, the NCGs generated by the process may not meet permissives for a period of 

time, and the NCGs will have to be vented for safety reasons due to the increased variations in 

the process during starting up and shutting down. The commenter indicated that same thing is 

true of startup or shutdown of a primary or backup incineration device (which may be a boiler, 

recovery furnace, lime kiln, or other combustion unit that is also part of the pulp mill operation), 

during which the conditions in the incineration device may not meet permissives for a period of 

time, and it will be necessary to bypass the NCGs around that device to avoid explosion. As

another example, the commenter cited the requirements in §63.453 to monitor operating 

parameters in lieu of, or in addition to, monitoring emissions. According to the commenter, 

operating parameters established to represent proper operation during normal operating 

conditions will often be different from the operating parameters that apply when a unit is being 

started up or shut down.

Similarly, commenter 0172 stated that in the preamble to the proposed rule, EPA asserted

that startup and shutdown operations are as routine and predictable as normal operations and can 

be controlled, so that emissions are the same as during routine operations. The Agency also 

believes that as long as control devices are started up before the process and shut down after the 

process is down, emissions can be controlled to the same degree as during “normal” operations. 

Commenter 0172 stated that EPA’s assertions do not reflect the reality of operations in heavy 

industrial processes, such as pulp and paper making. During startups and shutdowns, abnormal 

emissions may and frequently do occur because, by definition, the process equipment is not in a 

stable mode–it is being started up or shut down. Process flows, temperatures and pressures are 

constantly changing during the startup and shutdown process, resulting in unexpected diversions 

from the planned startup or shutdown procedures. These unexpected diversions can lead to 

emissions that are higher than those when the process is in routine operation.

Commenter 0172 noted that, even if there is a control device which has been energized 

and is operating normally, it may be physically located at the end of a long piping system 

collecting emissions from more than one piece of process equipment (such as an incinerator 

collecting vent gases from an LVHC system regulated under subpart S). During the unstable 

operating conditions that occur during startup or shutdown, it may be necessary to vent gases 

directly from a process unit (such as to compensate for unexpected over-pressurization) to 

prevent damage to the process equipment.
117

According to another commenter (0163), EPA’s conclusion that startup and shutdown 

periods are “predictable and routine aspects” of normal operations fails to recognize that, while 

timing and process steps may be foreseeable, the specific circumstances with many of these 

events may be unique. The commenter contended that EPA cannot include these events under the 

current or proposed subpart S emissions standards because they were not necessarily considered 

part of the original MACT floor emission evaluation. Instead, the commenter recommended that 

EPA consider its decision in the March 2011 final Boiler MACT rules to set work practices for 

startup and shutdown events, which reversed their 2010 proposed rule assumption that emission 

limits set for normal operating periods reflected and could legally apply as well during these 

events.

In addition, commenter 0164 stated that EPA does not appear to have performed a 

scientific analysis that would justify reversing that determination for startup and shutdown 

events, and, for malfunction events, EPA acknowledges that even well-designed and welloperated mills will exceed the standards.

Response: As explained earlier, we do not claim that the Sierra Club decision constrains 

our authority to prescribe unique standards during SSM periods. But there must be a basis for our 

determination to prescribe standards other than MACT emission limits during those events. The 

EPA, under CAA section 112(h) authority can also, in cases where it is not feasible to prescribe 

or enforce an emission standard, promulgate a design, equipment, work practice, or operational 

standard (or combination thereof). The phrase “not feasible to prescribe or enforce an emission 

standard” is defined narrowly in section 112(h)(2) to mean “any situation in which the 

Administrator determines that: (A) a hazardous air pollutant or pollutants cannot be emitted 

through a conveyance designed and constructed to emit or capture such pollutant, or that any

requirement for, or use of, such a conveyance would be inconsistent with any Federal, State or 

local law, or (B) the application of measurement methodology to a particular class of sources is 

not practicable due to technological and economic limitations.”(emphasis added)

The EPA has adopted work practice standards for startup and shutdown periods in other 

rules (e.g., for industrial boilers, and electric utilities) where there was process-specific 

justification for work practices considering the criteria specified by CAA section 112(h). The 

specific work practices set forth in the industrial boiler and electric utility standards were 

developed for combustion processes and are not applicable for the diverse assortment of 

emission units subject to subpart S. Development of separate emissions standards (separate 

numeric limits or work practices) for startup and shutdown of pulp and paper processing 

equipment requires consideration of emission unit, collection system, and control device 

operation; compliance option used; and methods for demonstration initial and continuous 

compliance.

Although the commenters suggest that different standards should be adopted for startup 

and shutdown periods (i.e., other than the standards that apply during normal operation), the 

commenters have not provided specific information to indicate that separate standards are 

justified or to explain specifically how application of the normal operational standards in subpart 

S would be violated during startup or shutdown (other than for periods covered by the excess 

emissions allowances for NCG systems). The commenters also do not suggest any specific 
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standards that could apply during startup and shutdown for the universe of pulp and paper 

processes regulated under subpart S (which offers a variety of compliance options). 

Commenters repeatedly point to NCG collection system venting as an example of why

EPA should have special provisions for startup and shutdown events. The EPA views the 

amendments to remove the SSM exemption (through corrections to GP references) as a separate 

issue from the excess emissions allowances. Commenters have indicated that the excess 

emissions allowances are used during normal operational time periods and that these periods of 

excess emissions should not be considered malfunctions. Under the subpart S amendments being 

promulgated, the same standards apply for normal operation, startup, and shutdown, so there is 

no reason to distinguish between normal operation, startup, and shutdown in the excess 

emissions allowance provisions. (Only malfunction will be handled separately through 

availability of the affirmative defense provisions.) As noted in Section 8 of this document, we 

received additional information from the industry to aid in our investigation of the excess 

emissions allowances and will take action on these allowances at a later date. If, upon further 

analysis of the information provided by industry, we find reasons to distinguish between 

startup/shutdown periods and normal operations in the context of our approach for handling the 

excess emissions allowances, then we will address those concerns when we propose our findings 

relative to the excess emissions allowances. However, under the subpart S amendments being 

promulgated, EPA considers the SSM exemption a separate issue decoupled from the excess 

emissions allowances and is proceeding with removal of the SSM exemption.

The EPA proposed (and is finalizing in the subpart S amendments) removal of the 

parenthetical references to SSM from the excess emissions allowance language in subpart S. For 

the 1 percent LVHC and 4 percent HVLC allowances, the parenthetical language in §63.443(e)

that allowed the SSM exemption in addition to the venting allowances has been removed from 

subpart S. The parenthetical language in §63.446(g) clarifying that the 10 percent steam stripper 

venting allowance included periods of SSM has also been removed. This parenthetical language 

was originally included in the rule because EPA had no information to “differentiate SSM 

emissions from normal stripper operating emissions” when originally reviewing the data that 

formed the basis for the 10 percent steam stripper venting allowance. (63 FR 18530, April 15, 

1998) Thus, the commenter’s assertion is incorrect that EPA “specifically considered the need 

for special provisions to address higher emissions occurring during startup and shutdown as 

reflected in EPA’s decision to include startup and shutdown periods in the excess emission 

provision for condensate treatment but not for LVHC and HVLC NCG controls” (emphasis 

added).

We have assembled information from the 2011 pulp and paper ICR pertaining to 

equipment, control, and compliance demonstration methods in order to address the commenters’ 

concerns that EPA’s conclusion that separate standards are not needed for periods of startup and 

shutdown is not supported and based on “mere speculation.” The ICR contained questions 

designed to provide EPA with an understanding of the duration, emissions potential, work 

practices, and control mechanisms of startup and shutdown events for the wide variety of 
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equipment used at pulp and paper mills. This information is summarized below and detailed in a 

separate memorandum in the docket.

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For emission unit startup and shutdown, the survey asked:

 Approximate duration of emission unit startup and shutdown (hours). [2 questions]

 Measures employed to reduce air emissions during emission unit startup and shutdown (if 

any). [2 questions]

 What marks the end of emission unit startup and beginning of normal operating 

conditions?

 What marks the end of normal operating conditions and beginning of emission unit 

shutdown?

 An optional suggestion for a standard that would apply during startup or shutdown of this 

emission unit.

For control device startup and shutdown, the survey asked:

 Approximate duration of control device startup and shutdown (hours). [2 questions]

 Explain how control device startup and shutdown is integrated with (dependent upon)

emission unit startup and shutdown. [2 questions]

 List any control device continuous emissions monitoring or operating parameter limits 

that cannot be met during control device startup or shutdown. [2 questions]

 Measures employed to reduce air emissions during control device startup and shutdown 

(if any). [2 questions]

 What marks the end of control device startup and beginning of normal operating 

conditions?

 What marks the end of normal operating conditions and beginning of control device 

shutdown?

The ICR also contained optional questions, where respondents were asked to suggest a 

separate standard that could apply during emission unit and control device startup or shutdown.

No useful suggestions for separate standards were received. 

Responses to survey questions asking what marks the beginning and end of normal 

operations for emission units and control devices were very site-specific in nature. This stands to 

reason because mills formerly defined startup and shutdown—in consideration of their specific 

equipment and operational practices—in their SSM plans. The only conclusion we could draw 

from the responses to these questions is that defining the beginning and end of startup and 

shutdown periods in a way that makes sense for all mills in the nation would be very difficult, if 

not impossible. However, it would have been necessary for EPA to define the beginning and end 

of startup and shutdown if EPA were to adopt separate standards to apply during these periods

(i.e., so it would be clear which standard is applicable at any given time).

Subpart S contains standards for:

 Kraft, soda, and semichemical pulping vent gases (§63.443);

 Sulfite pulping vent gases (§63.444);

 

132 See memorandum by K. Hanks, RTI, to J. Bradfield and B. Schrock, EPA, titled Review of Pulp and Paper 

Information Collection Request (ICR) Responses Pertaining to Startup and Shutdown of Subpart S Equipment, June 

22, 2012, in the docket for the subpart S rulemaking.
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 Bleaching vent gases (§63.445);

 Closed-vent systems used to transport pulping or bleaching vent gases (§63.450); and

 Kraft pulping condensates (including closed collection systems for kraft condensates)

(§63.446).

Some mills are complying with selected subpart S standards through use of the CCA or 

other site-specific options (e.g., equivalency-by-permit). At many mills, the technologies used 

for site-specific compliance options are the same as those used to comply with the standards 

noted above (e.g., through controlling more condensates or equipment than are required to be 

controlled). Therefore, we believe consideration of the equipment and standards listed above 

(and described in detail below) provides sufficient consideration for site-specific compliance 

options. While we cannot purport to having considered every single aspect of every U.S. mill’s 

equipment and operations in our consideration of the need for separate startup and shutdown 

standards, we do believe that we have covered the majority of mills and their equipment types in 

our review. Site-specific compliance approaches were set through site-specific reviews by

permitting authorities and may need to be revisited should our conclusions relative to startup and 

shutdown for the majority of equipment not address a site-specific situation.

Kraft, Soda, and Semichemical Pulping Vent Gases. We believe that mills would remain 

in compliance with the kraft, soda, and semichemical pulping vent gas emission standards during 

emission unit or control device startup and shutdown, and we have concluded that separate 

standards for startup and shutdown are not necessary for pulping vent gases for several reasons. 

First and foremost, the survey data indicate that mills usually begin operation of their 

incineration control device prior to emission unit startup and continue operating their 

incineration control device until emission unit shut down has occurred. Mills implementing this 

practice meet the required design standards and parameter monitoring requirements during 

emission unit startup and shutdown. Incineration control devices include boilers, lime kilns, 

recovery furnaces, or thermal oxidizers.

Second, control device startup and shutdown are often addressed at pulp and paper mills 

through the use of backup controls. We believe that, in most cases, boilers would start up before 

most other emissions units because boilers provide steam and power needed to operate emissions 

units. Similarly, recovery furnaces often provide steam and power for emission units. Although 

some incineration devices may need to follow a startup sequence (e.g., a recovery furnace that 

does not begin normal operation until spent liquor is available from digesters; or a lime kiln that 

does not begin normal operation prior to smelt being generated from the recovery furnace and 

moves through the causticizing process), we note that these devices can begin to start up on 

auxiliary fuels prior to processing of spent liquor (for a recovery furnace) or calcium carbonate 

(for a lime kiln). Many mills also have stand-alone thermal oxidizers that are used as backup 

controls when process units such as lime kilns or recovery furnaces are used as the control 

device.

Third, there are five separate compliance options for pulping vent gases. The two most 

commonly used compliance options are based on equipment design133 and do not involve any

 

133 The design-based compliance options require mills to: 
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emissions or parameter monitoring that would show mills to be out of compliance. As long as 

emissions are collected in the closed-vent system and routed to these operational controls, then 

mills would be in compliance with the standards. The remaining compliance options involve 

firebox temperature monitoring or optional use of methanol continuous emissions monitoring 

systems (CEMS). The survey data reveal than no mills are using methanol CEMS. If an 

incineration control device is operational prior to emission unit startup and until emission unit 

shutdown is complete then there is no reason for a temperature parameter limit to be exceeded 

during emission unit startup or shutdown. Although the firebox temperature parameter may be 

out of compliance during incineration control device startup or shutdown (e.g., as the 

incineration device warms or cools), we believe, based on the survey results, that this 

circumstance is being mitigated though use of backup controls or by not starting the emission 

unit until the control device combustion temperature has been reached at most mills. An 

emergency startup or shutdown (e.g., when a “hot” backup thermal oxidizer may not be 

available, and the boiler or lime kiln is not an option), which resulted in a violation of a standard, 

could arguably be considered a malfunction, and the affirmative defense provisions would be 

available in this instance. 

Overall, we believe the availability of multiple compliance options (of which the most 

frequently used are based on equipment design) and widespread use of backup incineration 

controls makes it possible for mills to comply with the pulping vent gas standards during startup 

and shutdown. Therefore, separate standards during startup and shutdown were not developed for 

kraft, soda, and semichemcal pulping vent gases.

We acknowledge that every mill may not have backup controls available for NCG 

systems (e.g., HVLC systems), either because they have not installed closed-vent collection 

ductwork to transfer vent gases to a backup incineration device or because a backup incineration 

device is not available. The need for separate startup or shutdown standards at these mills is most 

likely mitigated through use of compliance options that are based on equipment design.

Sulfite Pulping Vent Gases. Based upon the ICR results, six sulfite mills remain in 

operation in the U.S., including:

 Three ammonia-based sulfite mills;

 Two calcium-based sulfite mills; and

 One sodium-based sulfite process collocated at a kraft mill.

These mills operate absorbers (scrubbers) for control of pulping vent gases and are 

required by subpart S to demonstrate continuous compliance through continuous parameter 

monitoring of effluent pH (or oxidation/reduction potential), inlet vent gas flow rate, and 

scrubber liquid influent flow rate. The scrubbers used at sulfite mills employ a type of fresh 

water (e.g., river water, well water) with caustic addition. Flow of fresh water to the scrubber 

(scrubber liquid influent rate) is not dependent on other pulping emission units within the mill 

(nor is caustic addition since the caustic is not coming from any pulping by-product).

 

 Use a boiler, lime kiln, or recovery furnace in which the HAP gas stream is introduced with the primary 

fuel into the flame zone; or

 Use a boiler or recovery furnace with a heat input capacity ≥150 MMBtu/hr (44 MW) in which the HAP 

gas stream is introduced with the combustion air.
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Survey data reveal that scrubbers are started up and meeting required operating parameter 

limits before the emission unit is started up; and that the scrubbers remain in operation until the 

emission unit is shut down. No issues with meeting subpart S operating parameters were 

identified in the ICR responses. Therefore, we have concluded that separate standards for startup 

and shutdown are not necessary for sulfite pulping vent gases.

Bleaching Vent Gases. Bleach plants typically use caustic scrubbers to reduce HAP 

emissions. Process waters such as white liquor, weak wash, or caustic are commonly used and 

recycled within bleach plant scrubbers. Scrubber blow down - the fraction of scrubber liquid that 

is purged from the system and replaced by new liquid - is either recycled in the process (e.g., 

within the bleaching or ClO2 process) or sent to the wastewater treatment system. The ability of 

bleach plant scrubbers to recycle scrubbing liquid within the scrubber system serves as a buffer 

to reduce dependency of the scrubber system on other mill processes during brief periods of 

scrubber startup or shutdown. Startup and shutdown times reported in the ICR responses for 

bleach plant scrubbers were around half an hour (30 minutes).

An initial performance test is required for bleach plant scrubbers. In addition to the 

5-year repeat performance test required with the current amendments to subpart S, continuous 

compliance for bleaching scrubbers is demonstrated by continuous parameter monitoring of 

effluent pH (or oxidation/reduction potential [ORP]), inlet gas flow rate, and scrubber liquid 

influent flow rate. Continuous monitoring of Cl2 concentration is allowed as an alternative to 

continuous parameter monitoring; however, no mills reported use of Cl2 CEMS in the survey

responses. Several mills reported use of ORP instead of pH. Fan motor amps, revolutions per 

minute (rpm), or fan on/off status are often monitored as indicators of inlet gas flow rate. The 

survey data revealed few (if any) issues where parameter limits are not met during bleaching 

scrubber startup and shutdown. (Where one column of a survey response suggested a parameter 

limit might not be met, other columns stated the opposite for the same scrubber.) Therefore, we 

have concluded that separate standards for startup and shutdown periods are not warranted for 

bleach plant scrubbers. 

Closed-Vent Systems Used to Transport Pulping or Bleaching Vent Gases. The subpart S 

standards for closed-vent gas collection systems contain requirements for: 

 Enclosures, openings, and hoods;

 Components operated at positive pressure; and

 Bypass lines that could divert vent streams containing HAPs to the atmosphere.

Mills must maintain negative pressure at enclosures, openings, and hoods. If the 

enclosure, opening, or hood is closed during the initial performance test, it must remain closed 

during operation, except for sampling, inspection, maintenance, or repairs. Compliance with 

these requirements is demonstrated by following a site-specific inspection plan required in 

§63.454(b), where visual inspections of enclosure openings are required every 30 days per 

§63.453(k)(1). Given the 30-day frequency of these inspections, there seems to be little chance 

that mills would be found out of compliance with this requirement during startup and shutdown. 

We are unaware of any reason why enclosures, openings, and hoods would not remain closed or 

maintain negative pressure during startup or shutdown.
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Mills are required to operate with no detectable leaks (less than 500 parts per million by

volume [ppmv] of volatile organic compounds [VOC] above background) for collection system 

components operated at positive pressure. Compliance is measured with initial and annual part 

60, Method 21 leak detection tests. Even if leak detection tests were conducted during startup 

and shutdown, it is not expected that startup and shutdown would change the potential for leaks 

beyond the potential that exists during normal operation, because gas flow volumes are likely to 

be lower during startup and shutdown.

Bypass lines that could divert vent streams containing HAPs to the atmosphere are 

required to either:

 Operate a computer-controlled flow indicator to monitor for presence of gas stream flow 

in the bypass line at least once every 15 minutes; or

 Maintain bypass line valves that are not computer controlled in the closed position, sealed 

so that the valve or closure mechanism cannot be opened without breaking the seal.

Compliance with these requirements is demonstrated by following the site-specific 

inspection plan required in §63.454(b), where visual inspections of enclosure openings are 

required every 30 days per §63.453(k)(1). Bypass line valves that are sealed during normal 

operation should stay sealed during startup and shutdown (unless a seal is broken due to a 

malfunction event for which affirmative defense is available). There is no reason to expect a 

different standard is needed during startup and shutdown for closed, sealed bypass line valves.

Multiple emission units feed into closed-vent systems. Commenters have indicated that 

gas flow rate into collection systems (and internal system pressures) can vary, as emission units 

are started up or shut down. Computer-monitored bypass lines could show some safety-related 

venting during startup and shutdown until flows within the collection system are within lower 

explosive limit (LEL) or upper explosive limit (UEL) permissives, and flows are balanced. This

safety-related venting is currently covered under the 1 and 4 percent excess emissions 

allowances for LVHC and HVLC systems, respectively. The need for separate startup and 

shutdown standards for computer-controlled bypass line valves can be evaluated further when 

EPA takes action on the excess emissions allowances.

Kraft Pulping Condensates (Including Closed Collection Systems for Kraft Condensates). 

Kraft pulping condensates are HAP-containing liquids that are condensed from pulping system 

vent streams, including condensates from digesters, turpentine recovery, evaporators, LVHC 

systems, and HVLC systems. The LVHC and HVLC collection system condensates are 

generated by condensation of moisture in the closed-vent collection systems that convey the 

LVHC and HVLC system vent gases to a control device.

The subpart S kraft pulping condensate standards include standards for condensate 

collection and standards for condensate treatment. The kraft condensate collection standards 

include three options: 

 Collect all named condensate streams.

 Collect all LVHC and HVLC streams plus streams that contain 65 percent of the total 

HAP mass from the digester system, turpentine recovery system, and evaporator system 

feed stages.
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 Collect any subset of the named streams that contain in total 7.2 lb of HAP per ODTP at 

mills that do not perform bleaching, or 11.1 lb HAP per ODTP at mills that perform 

bleaching.

Kraft condensates are to be conveyed in a closed collection system that meets the 

requirements in §63.446(d) of subpart S for individual drain systems and condensate tanks. A 

mill can meet the closed collection system requirements in two ways:

 Hardpiping; or

 Use existing drains, but cover all openings and route all open vents through a closed-vent 

collection system to a control device meeting the subpart S NESHAP requirements for 

pulping system vents.

Closed collection systems used to transport pulping process condensates containing 

HAPs must meet all of the individual drain system requirements specified in §§63.960, 63.961, 

and 63.962 of 40 CFR part 63, subpart RR (National Emission Standards for Individual Drain 

Systems), except that any air vents in the collection system must comply with the kraft pulping 

vent gas collection and HAP reduction standards in §63.443 (c) and (d) of subpart S. Subpart RR 

establishes design, operating, inspection, and monitoring requirement standards for controlling 

air emissions from individual drain systems. The standards control emissions from individual 

drain systems using covers or seals, or hard-piping. Subpart RR also requires inspections of 

water seals and closure devices for defects or damage initially and establishes repair 

requirements for individual drain systems. The closed collection system must be visually

inspected every 30 days according to §63.964 of subpart RR.

For condensate tanks, §63.446(d)(2) specifies:

 The fixed roof and all openings (e.g., access hatches, sampling ports, gauge wells) shall 

be designed and operated with no detectable leaks as indicated by an instrument reading 

of less than 500 ppm above background, and vented into a closed-vent system that meets 

the requirements in §63.450 and routed to a control device that meets the requirements in 

§63.443(d); and

 Each opening shall be maintained in a closed, sealed position (e.g., covered by a lid that 

is gasketed and latched) at all times that the tank contains pulping process condensates or 

any HAP removed from a pulping process condensate stream, except when it is necessary

to use the opening for sampling, removal, or for equipment inspection, maintenance, or 

repair.

Compliance with the standards for the different components of closed condensate 

collection systems is based on system design (e.g., covers, seals, or hard-piping), and continuous 

compliance is based on periodic leak checks and inspections. Openings in the condensate liquid 

collection system that are sealed during normal operation should also be sealed during system 

startup and shutdown (expect, perhaps, for a malfunction or operator error). Periods of startup 

and shutdown are not likely to result in violation of the periodic leak check and inspection 

requirements. We are not aware of any reasons why separate standards for closed condensate 

collection systems would be needed for startup and shutdown periods. 
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Once collected, kraft pulping condensates must be treated according to one of the 

following subpart S treatment standards:

 Recycling: Route condensates through a closed vent collection systems to pulping 

equipment controlled by the Subpart S kraft pulping vent gas standards; or

 Route the condensates to biological treatment, steam stripper or other control device that 

meets one of the following equivalent requirements:

o Reduce total HAP by at least 92 weight-percent; or

o For mills without bleaching, either remove at least 6.6 lb total HAP/ODTP, or 

meet 210 ppmw total HAP at the control device outlet; or

o For mills with bleaching, either remove at least 10.2 lb total HAP/ODTP, or meet 

330 ppmw total HAP at the control device outlet.

For the condensate recycling treatment option, the compliance demonstration would 

consist only of verifying that no leaks were present in the condensate closed collection system, 

and confirming closed vent gas system and control device requirements are met. We discussed 

the kraft pulping vent gas standards above, and concluded that separate standards for startup and 

shutdown are not warranted for kraft pulping vent gases. As also noted above, we are not aware 

of any reasons why separate standards for closed condensate collection systems would be needed 

for startup and shutdown periods. Thus, it follows that separate startup and shutdown standards 

would not be needed for control of condensates through recycling to pulping equipment subject 

to the pulping vent gas standards.

Mills controlling kraft condensates with steam strippers or other equipment serving the 

same function (e.g., an in-process anaerobic biotreatment unit, wastewater thermal oxidizer, etc.) 

must perform an initial performance test for total HAP (measured as methanol) using 40 CFR 

part 63 Method 305 or NCASI method DI/MEOH-94.03. Inlet and outlet testing is required for 

mills complying with the percent reduction or lb/ODTP collection and removal standards. Only 

outlet testing is required for mills complying with the ppmw condensate standards. Alternatively, 

measure the steam stripper methanol outlet concentration (ppmw). The ICR results reveal that 

only one mill is using the ppmw option (a mill with a thermal oxidizer), and this mill is not using 

a methanol CEMS to demonstrate compliance. Mills operating equipment other than steam 

strippers must petition the Administrator for approval of site-specific monitoring requirements.

For mills using steam strippers, subpart S requires that ongoing compliance be 

demonstrated by continuous parametric monitoring of the process wastewater feed rate, steam 

feed rate and process wastewater column feed temperature. Although not specified explicitly in 

subpart S, the steam feed rate and condensate feed temperature parameter limits are minimum 

limits that relate to how much heat must be applied in the steam stripper system in order to strip 

organics into the vapor phase. The steam-to-feed ratio (SFR) is the stripper operating parameter 

with the greatest effect on stripper performance. This ratio is monitored through subpart S by

dividing the monitored steam feed rate by the process wastewater feed rate. A larger SFR would 

result in more organics being stripped from the wastewater. Steam feed rate is likely

automatically controlled in conjunction with wastewater feed rate to ensure a minimum SFR is 

maintained.
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The ICR responses were reviewed to determine if mills reported issues with maintaining 

compliance with the parametric monitoring requirements during startup and shutdown. Mills 

generally indicated that stripper operation would begin after the pulping vent gas collection and 

control system is ready to accept stripper off gases, and after pulping processes have operated 

long enough for condensates to be generated for input into the steam stripper. Some mills noted 

that condensates may be sent to biotreatment for backup until the stripper is fully operational, 

that stripper operation does not begin until a sufficient level of condensates has been collected in 

the condensate tank, or that condensates must reach a specified temperature before they are sent 

to the stripper. Adequate condensate tank capacity serves as a buffer between the pulping process 

and steam stripper (e.g., allowing collection of condensates for a short time while the stripper is 

offline or in startup/shutdown mode). Using the maximum of any ranges provided by

respondents (e.g., for cold startup), the median startup and shutdown times for condensate 

strippers provided in the ICR responses (Equip detail tab) was 1 hour, with an average of 2 to 

3 hours. No specific issues indicating the inability of mills to meet the stripper operating 

parameter limits during startup or shutdown were observed in the ICR responses. Therefore, we 

conclude that separate standards during startup and shutdown periods for kraft condensates 

controlled by steam strippers are not necessary.

Mills using biological wastewater treatment to control kraft condensates must perform an 

initial test followed by quarterly sampling to determine the fraction of methanol biodegraded. 

The testing requirements differ somewhat for biotreatment systems that are thoroughly mixed 

versus non-thoroughly mixed, but the continuous parameter monitoring requirements are the 

same. Subpart S requires that mills monitor daily the outlet soluble 5-day biochemical oxygen 

demand (BOD5) concentration, mixed liquor volatile suspended solids (MLVSS), horsepower of 

aerator units, inlet liquid flow, and liquid temperature. In addition, mills must obtain daily inlet 

and outlet liquid grab samples from each biological treatment unit to have HAP data available to 

perform quarterly performance tests and to store until after the BOD5 results are obtained.

Alternatively, mills can conduct daily monitoring of the site-specific parameters approved by the 

Administrator. Biological wastewater treatment systems (e.g., ASBs or AST units) differ from 

in-process condensate treatment technologies (e.g., steam strippers or in-process biotreatment 

units dedicated to condensate control), because these wastewater treatment systems typically 

accept wastewaters from all over the mill and must be up and running at all times to comply with 

National Pollutant Discharge Elimination System (NPDES) requirements under the CWA. 

Therefore, we concluded that special standards that would only apply during startup and 

shutdown are not relevant for mill wastewater treatment systems that treat condensates but also 

accept process waters from all over the mill. Mill-wide biological wastewater treatment systems

were similarly distinguished from in-process condensate controls in our clarification that the 

10 percent excess emissions allowance does not apply for these systems. (63 FR 49457, 

September 16, 1998)

Summary. To summarize, we have reviewed the information available to us regarding 

startup and shutdown periods. We believe that the expected startup and shutdown emissions (as 

indicated through the continuous compliance requirements implemented for subpart S) are not 

likely to cause a violation of the standards. We also found no evidence that suggested that 

emissions were higher during startup or shutdown that would indicate a need for an alternate 

standard for these periods. The commenters have not shown that sources cannot comply with the 
127

standards as proposed, and have not provided information to support development of alternative 

standards that would apply during startup and shutdown periods. Thus, we set standards based on 

available information as directed by section 112. The standards that apply during normal 

operation will also apply during startup and shutdown.

7.3 Malfunction and Affirmative Defense

86. Comment: Commenters 0162 and 0172 argued that EPA is required to take malfunctions 

into account when adopting emission standards. Commenter 0162 stated that EPA offered very

little support for its assertion that its approach to malfunctions in setting emissions standards “is 

consistent with CAA section 112 and is a reasonable interpretation of the statute” (76 FR 81347), 

other than stating its own, often counterintuitive, conclusions. As an example, commenter 0162

indicated that EPA made little effort to justify its assertion “that CAA section 112 does not 

require that emissions that occur during periods of malfunction be factored into development of 

CAA section 112 standards” (76 FR 81346). Commenter 0162 also said that EPA had it 

backward when it said that “[t]here is nothing in CAA section 112 that directs the Agency to 

consider malfunctions in determining the level ‘achieved’ by the best-performing or best 

controlled sources when setting emission standards” (76 FR 81326). According to commenter

0162, there is nothing in CAA section 112 that allows EPA to ignore malfunctions and set 

MACT standards based on a level of emissions that even best-performing sources only achieve 

part of the time.

Commenter 0162 argued that EPA also offered a backwards, results-driven rationale for 

ignoring malfunctions, that “accounting for malfunctions could lead to standards that are 

significantly less stringent than levels that are achieved by a well-performing nonmalfunctioning source” (76 FR 81347). The commenter stated that this rationale directly 

contravenes congressional intent that MACT “floor” standards be based on what the best sources 

actually achieve. According to the commenter, EPA cannot ignore the requirement that MACT 

“floor” standards reflect performance actually achieved, just because EPA would like the 

standards to be more stringent than that actual performance reflects.

According to commenter 0162, EPA acknowledges that even properly designed and 

operated equipment will sometimes exceed emission limitations that were based on steady-state 

operation, due to malfunctions (76 FR 81347). The commenter noted that even the bestperforming units in the source category covered by the proposed rule (like any technologies) are 

subject to a wide variety of potential malfunctions (e.g., power failures, equipment breakdowns) 

(76 FR 81346). The commenter explained that operators of these processes and equipment must 

treat malfunctions as very distinct events from steady-state operations, depending on the severity 

of the malfunction, requiring anything from shutdown of the unit to emergency fire response

actions. The commenter agreed with EPA’s conclusion that the factual complexity of differing 

processes and of the severity, frequency, and duration of malfunctions makes standard-setting 

difficult (76 FR 81346). The commenter added that it is often infeasible to gather emissions data 

during malfunctions–either for standard-setting or for compliance-demonstration purposes—

because malfunctions are by definition unexpected and infrequent, so it is not possible to plan to 

have test equipment in place to measure emissions when one occurs. According to the 

commenter, even if test or monitoring equipment is in place, emissions during malfunctions 
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often are not routed to a stack where they can be measured, and upsets during stack testing 

invalidate the test results under EPA’s approved test methods.134

The commenter argued that these findings should lead EPA to prescribe alternative 

design, equipment, work practice or operational standards where it is not feasible to set or 

enforce a numerical emission limit, based on its authority under CAA section 112(h), rather than 

support EPA’s decision to ignore the fact that SSM events can lead to higher emissions even at 

well-operated facilities with the best control equipment. According to the commenter, EPA 

cannot rationally defend its articulated view that applying the concept of “best performing” is 

inconsistent with a source experiencing a malfunction (76 FR 81346) because it ignores that 

there are work practices (e.g., monitoring operating parameters to identify a malfunction and 

stopping or cutting back the process accordingly) that represent the best practices for minimizing 

emissions during a malfunction. The commenter pointed out that, while the measures that 

represent these best practices will depend on facility-specific issues, such as process design, 

pollution control train, and other factors, they nonetheless represent "the maximum degree of 

reduction in emissions of the hazardous air pollutants...achievable...through application of 

measures, processes, methods, systems or techniques" and reflect "the emission control that is 

achieved in practice by the best controlled similar source[s]" CAA section 112(d)(2) and (3).

Commenter 0163 agreed that the CAA does not require EPA to include the emissions 

from malfunction events in the limitations it sets for normal operating periods, since those 

emissions typically cannot reasonably be measured or monitored, but those emissions also are 

not amenable to regulation under specific emission limits. A single emission limitation that 

applies even though it cannot be met during malfunction (or startup or shutdown) events does not 

represent a limitation “achieved in practice,” as required by CAA section 112(d)(3). The original 

subpart S MACT standards for pulping sources were written with the understanding that excess 

emissions associated with SSM events would not be considered violations of the standards, either 

because of specific provisions of the regulations or because of the now vacated exemption in the 

NESHAP GP. Because of the court decision and the underlying CAA achievability criteria, the 

commenter believes EPA must focus its reassessment of malfunction standards applicable to the 

pulping and bleaching processed in a way that captures the fundamental information on best 

performers on which the current standards were based.

Response: Based on Response from Mineral Wool. The EPA provided a detailed 

justification in the preamble to the proposed rule for its approach to malfunctions. As the D.C. 

Circuit Court noted in Sierra Club v. EPA, 167 F. 3d 658 (D.C. Cir. 1999), the phrase "average 

emissions limitation achieved by the best performing 12 percent of units” in section 112 of the 

CAA "says nothing about how the performance of the best units is to be calculated.” Id. at 661. 

Congress has not directly addressed the issue of whether emissions that occur during periods of 

malfunction must be taken into account in calculating the performance of the best units, and 

EPA’s approach to malfunctions is reasonable for the reasons set out in the preamble to the 

proposed rule. For example, EPA explained, and the commenter agrees, that the factual 

 

134 Commenter 0162 noted that EPA acknowledged these potential obstacles to measuring emissions during SSM 

events in the preamble to final emission standards for medical waste incinerators (74 FR 51368, 51394 (Oct. 6, 

2009)), which said: “It would be very difficult to do any meaningful testing during such an event because the 

exhaust flow rates, temperatures, and other stack conditions would be highly variable and could foul up the 

isokinetic emissions test methods (thus invalidating the testing).”
129

complexity of differing processes and of the severity, frequency, and duration of malfunctions 

makes standard-setting impracticable. In fact, the commenter’s statement that the best work 

practices employed during malfunctions “will depend on facility-specific issues, such as process 

design, pollution control train, and other factors” highlights the impracticability of setting work 

practice standards that apply across all sources in the category for the myriad types of

malfunction that could occur. The commenter does not explain how any of the options suggested 

would make it any easier or practicable for EPA to set a national standard that accounts for the 

innumerable types of malfunctions that, as commenter points out, might vary depending on 

facility-specific issues. The EPA further explained that the performance of units that are 

malfunctioning is not reasonably foreseeable and cited to case law supporting its approach to 

malfunctions. See Sierra Club at 665 (discussing need to take into account the worst reasonably 

foreseeable performance) and Weyerhaeuser v. Costle, 590 F.2d 1011, 1058 (D.C. Cir. 1978) 

(“In the nature of things, no general limit, individual permit, or even any upset provision can 

anticipate all upset situations.”).

In pointing out that “accounting for malfunctions could lead to standards that are 

significantly less stringent than levels that are achieved by a well-performing nonmalfunctioning source,” EPA was merely pointing out one possible consequence of taking 

malfunctions into account in setting standards if such an approach were practicable. This 

theoretical consequence is not driving EPA’s approach to malfunctions.

For all the reasons explained in the proposal preamble and above, EPA’s approach to 

malfunctions is reasonable and consistent with the statute regardless of whether collection of 

certain types of malfunction data under certain circumstances is theoretically possible.

87. Comment: Commenter 0162 rejected EPA’s claims that it somehow “presents significant 

difficulties” to attribute malfunctions to a “best performing” source (76 FR 81346), stating that it 

“presents significant difficulties” when EPA ignores the undisputed existence of malfunctions 

even at best performing sources, and claims falsely that the best performing sources “achieve” 

emission levels that they undisputedly do not achieve part of the time. The commenter argued 

that, since EPA describes malfunctions as being sometimes unavoidable or “not reasonably

preventable,” despite proper design and maintenance of equipment, there is no basis for EPA’s 

conclusion that malfunction events are not representative of best performing sources (76 FR 

81346). While the commenter acknowledged that one goal “of best performing sources is to 

operate in such a way as to avoid malfunctions of their units” (76 FR 81347), that is all the more 

reason why EPA must acknowledge the fact that those sources nevertheless experience 

malfunction events, rather than assume those emissions away.

Commenter 0163 stated that EPA may not be able to establish a reasonable specific 

emission limitation for these events, but they believe the Agency can establish a reasonable 

standard, such as appropriate additions to the venting allowances or, where allowance cannot be 

feasibly determined from the data, work practice standards under CAA section 112(h). The

commenter referred EPA to the detailed SSM Coalition comments on the proposed NESHAP 

modifications for the Mineral Wool and Ferroalloys industries.

Commenter 0162 further argued that EPA was going beyond the MACT “floor” by

proposing MACT standards that it recognizes even the best performing existing sources cannot 
130

achieve part of the time, but without making the demonstrations that the CAA and case law 

require EPA to make in order to impose beyond-the-floor MACT standards. The commenter said 

that this is especially obvious when one considers the many conditions EPA proposed to impose 

on sources during malfunctions, in order to be excused from civil penalties. According to the 

commenter, EPA made no attempt to justify those conditions as reasonable, “taking into 

consideration the cost of achieving such emission reduction, and any non-air quality health and 

environmental impacts and energy requirements....” (CAA section 112(d)(2)).

Commenter 0162 also noted that EPA did not provide any support for its belief that 

“[a]pplying the concept of ‘best controlled’ or ‘best performing’ to a unit that is malfunctioning

presents significant difficulties” in setting CAA section 112 standards (76 FR 81346). The 

commenter argued that it is indefensible for EPA to acknowledge that malfunctions are 

inevitable, even for the best performing sources, refuse to include emissions data representing 

malfunctions in calculating the MACT “floor” (76 FR 81346), and then require that those MACT 

“floor” limitations be met even during malfunctions.

Response: The commenter is incorrect in stating that the EPA’s malfunction provisions 

go beyond the MACT floor. The MACT floor was designed and calculated based on normal 

working operations, which does not include malfunctions. Malfunctions are not considered 

normal working operations because they are “sudden, infrequent, not reasonably preventable.”

Morever, the “conditions EPA proposed to impose on sources during malfunctions” are 

not conditions of compliance. Rather, the affirmative defense criteria are conditions to show that 

a source found to not be in compliance has operated the affected source in such a way as to make 

civil penalties inappropriate.

Based on Response to MATS Comment p. 55 The EPA is finalizing the proposed 

affirmative defense language for exceedances of the numerical emission limits that are caused by 

malfunctions with minor revisions as discussed below. The EPA recognizes that even equipment 

that is properly designed and maintained can fail and that such failure can cause an exceedance 

of the relevant emission standard. The EPA is including an affirmative defense in the final rule,

as we have in other recent section 111, 112, and section 129 rules, so as to balance the tension, 

inherent in many types of air regulation, to ensure adequate compliance while simultaneously

recognizing that, despite the most diligent of efforts, emission limits may be exceeded under 

circumstances beyond the control of the source. The EPA must establish emission standards that 

“limit the quantity, rate, or concentration of emissions of air pollutants on a continuous basis.” 

42 U.S.C. 7602(k) (defining “emission limitation and emission standard”). See generally Sierra 

Club v. EPA, 551 F.3d 1019, 1021 (D.C. Cir. 2008) (emissions limitations under CAA section 

112 must both continuously apply and meet section 112’s minimum stringency requirements, 

even during periods of startup, shutdown and malfunction). Thus, the EPA is required to ensure 

that section 112 emissions limitations are continuous. The affirmative defense for malfunction 

events meets this requirement by ensuring that, even where there is a malfunction, the emission 

limitation is still enforceable through injunctive relief. While “continuous” limitations, on the 

one hand, are required, there is also case law indicating that, in some situations, it is appropriate 

for the EPA to account for the practical realities of technology. For example, in Essex Chemical 

v. Ruckelshaus, 486 F.2d 427, 433 (D.C. Cir. 1973), the D.C. Circuit Court acknowledged that,

in setting standards under CAA section 111, “variant provisions” such as provisions allowing for 
131

upsets during startup, shutdown and equipment malfunction, “appear necessary to preserve the 

reasonableness of the standards as a whole and that the record does not support the ‘never to be 

exceeded’ standard currently in force.” See also, Portland Cement Association v. Ruckelshaus, 

486 F.2d 375 (D.C.Cir. 1973). Though intervening case law such as Sierra Club v. EPA and the 

CAA 1977 amendments calls into question the relevance of these cases today, they support the 

EPA’s view that a system that incorporates some level of flexibility is reasonable. The 

affirmative defense simply provides for a defense to civil penalties for excess emissions that are 

proven to be beyond the control of the source. By incorporating an affirmative defense, the EPA 

has formalized its approach to upset events. In a CWA setting, the Ninth Circuit required this 

type of formalized approach when regulating “upsets beyond the control of the permit holder.” 

Marathon Oil Co. v. EPA, 564 F.2d 1253, 1272-73 (9th Cir. 1977). But see, Weyerhaeuser Co. v. 

Costle, 590 F.2d 1011, 1057-58 (D.C. Cir. 1978) (holding that an informal approach is 

adequate). The affirmative defense provisions give the EPA the flexibility to both ensure that its 

emission limitations are “continuous” as required by 42 U.S.C. 7602(k), and account for 

unplanned upsets and, thus, support the reasonableness of the standard as a whole. 

Based on Response from MATS p. 55 In exercising its authority under section 112 to 

establish emission standards (at a level that meets the stringency requirements of section 112), 

the EPA necessarily defines conduct that constitutes a violation. The EPA’s view is that the 

affirmative defense is part of the emission standard and defines two categories of violation. If 

there is a violation of the emission standard and the source demonstrates that all the elements of 

the affirmative defense are met, only injunctive relief is available. All other violations of the 

emission standard are subject to injunctive relief and penalties. 

88. Comment: According to commenter 0162, if it is possible to gather sufficient 

representative data reflecting emissions during malfunctions, then EPA is obligated to consider 

those data in its MACT “floor” calculations for steady-state operating conditions. The 

commenter indicated that, to the extent EPA had access to continuous monitoring data for 

emission units covered by the NESHAP, EPA could have conducted analyses of emissions levels 

during malfunction events. The commenter noted that many types of sources are required by 

many state agencies to submit deviation reports or malfunction reports when they experience a 

malfunction that causes an exceedance of an applicable limitation and that EPA did not appear to 

have made any attempt to obtain and analyze such reports, in order to assess what type of 

requirement might reasonably apply to the subject emission units during malfunctions.

Response: The EPA does not agree with the premise of the comment. The EPA disagrees 

that any malfunction or collection of data captured during malfunctions could be predictive and 

representative of any other malfunction. Data gathered through malfunction or deviation reports 

cannot be used as the basis for setting a standard, but are the basis for the EPA’s assertion that 

malfunction periods are not a variant of normal operation with which EPA should apply a 

distinct numerical or work practice standard.

89. Comment: Commenters 0162 and 0172 pointed out that there are several options EPA 

could use for setting MACT standards under CAA section 112 that would apply during 

malfunction events. As an example, commenter 0162 noted that EPA might be able to establish 

an emission limitation that applies at all times, but that has an averaging time of sufficient 

duration that short, infrequent spikes in emissions due to malfunctions would not cause the 
132

source to exceed the emission limitation (while at the same time ensuring that the source does 

not operate in a way that causes frequent, lengthy excursions above the normal controlled 

emission rate). The commenter further noted that EPA also could use the flexibility accorded by

CAA section 302(k)—which defined “emission limitation” and “emission standard” to include 

“any requirement relating to the operation or maintenance of a source to ensure continuous 

emission reduction, and any design, equipment, work practice or operational standard 

promulgated under” the CAA—to address emissions during malfunction events through 

operational requirements rather than by applying the same limits on pollutant concentrations in 

exhaust gases that apply during normal operations. 

Commenters 0162, 0163, and 0172 also noted that EPA also could have concluded, as 

explained above, that it has grounds to exercise its authority under CAA section 112(h) to 

promulgate a design, equipment, work practice, or operational standard, or combination thereof, 

because it is not feasible to prescribe or enforce an emission standard. Commenter 0162 also 

suggested that EPA could use a combination of these approaches. According to the commenter, 

there is no indication in the proposed rule that EPA gave much, if any, consideration to these 

types of options. The commenter argued that there are ample reasons to reject EPA’s conclusory

assertions that it cannot take malfunctions into account when setting MACT standards for the 

subject source category. According to the commenter, EPA’s failure to evaluate these options 

thoroughly renders the proposed rule arbitrary and requires EPA to develop a new proposal.

Response: In addressing the commenters’ suggested alternatives regarding the EPA’s 

current stance on regulations during malfunction, none are viable options. Averaging emissions 

over a time period will not eliminate emissions of HAP that are unknown in quantity. By the 

commenter’s own admission, “it is often infeasible to gather emission data during malfunctions,” 

and without emission data for these events, they cannot be accounted for in averaging. As to the 

other suggestions of using a design, equipment, work practice, or operational standard to control 

during a malfunction under CAA section 112(h), please see the response to comment no. 86 in 

this section.

90. Comment: Commenter 0162 argued that the proposed affirmative defense provision is 

not a substitute for addressing malfunction events in the emission standards themselves. 

According to the commenter, EPA acknowledges that the sources subject to the proposed rule 

will sometimes be unable to comply because of malfunctions, even if their equipment is properly 

designed and maintained, through no fault of the source (76 FR 81347). However, the 

commenter noted that EPA is offering “affirmative defense,” rather than promulgating an 

emission standard that eliminates that situation, so that the regulated emission sources will be 

subject to differentiated requirements, achievable with the identified best technology during 

malfunction events. The commenter stated that the proposed affirmative defense provision shifts 

the burden to the source to prove that many various criteria are met and actions were taken by the 

source, in order to avoid “civil penalties.” The commenter further stated that these criteria bear 

no direct relation to the statutory factors for MACT standards under CAA sections 112. 

According to the commenter, including an affirmative defense provision does not cure EPA’s 

failure to set emission standards that are achievable during SSM events. The commenter 

contended that the proposed standards, incorporating affirmative defense, still do not represent 

emission limitations “achieved” by best-performing existing sources under CAA section 
133

112(d)(3), nor do they meet the criteria for establishing beyond-the-floor emission standards 

under CAA section 112(d)(2).

Commenter 0162 further noted that it is not even clear what the affirmative defense 

covers. According to the commenter, the proposed rule states that sources may assert an 

affirmative defense “to a claim for civil penalties for exceedances of such standards that are 

caused by malfunction, as defined in §63.2.”135 The commenter inquired whether the term “civil 

penalties,” which they said was not defined in the proposed rule, was intended to apply as well to 

a “civil administrative penalty” imposed by EPA under CAA section 113(d). (The commenter 

noted that the term “civil penalty” in other contexts means only penalties imposed by a court.) 

The commenter also inquired whether the affirmative defense applied to “noncompliance 

penalties” under CAA section 120, which apply, inter alia, to noncompliance with a section 112 

NESHAP. The commenter stated that, to meet the purported purpose of the affirmative defense, 

which is to provide relief from emission limitations that cannot be met at times even with 

equipment that is properly designed and maintained (76 FR 81347), the affirmative defense 

provision would need to apply to civil and administrative penalties, including noncompliance 

penalties.136

Commenter 0162 noted that it is also unclear how the affirmative defense would apply to 

enforcement actions by state and local governments, or to private citizen enforcement actions 

under CAA section 304. The commenter stated that the preamble to the proposed rule, for 

example, only refers to sources applying affirmative defense in an EPA enforcement action.137

The commenter stated that the affirmative defense provision should clearly state that it is 

applicable to enforcement actions by states or citizen-suit plaintiffs, as well.

According to commenter 0162, EPA does not give any explanation for why the 

affirmative defense would not be available for claims for injunctive relief.138 The commenter 

argued that if the excess emissions associated with the equipment or process failure are not

reasonably preventable, then there is no apparent reason why an affirmative defense to a claim 

for injunctive relief should not be available, as well. The commenter pointed out that, as a matter 

of law, injunctive relief may not be available in cases where a civil penalty cannot be imposed. 

See Sierra Club v. Otter Tail Power Co., 615 F.3d 1008 (8th Cir. 2010) (under concurrent 

remedy doctrine, injunctive relief for a CAA violation is barred when civil penalty is barred by 

statute of limitations).

Commenter 0162 further noted that maintaining liability for injunctive relief renders the 

affirmative defense particularly ineffective with respect to citizen suits. According to the 

commenter, if the source is even potentially subject to injunctive relief, and, therefore, could be 

 

135 See proposed 40 CFR 63.456.

136 Commenter 0162 noted that, in the preamble to the proposed rule, EPA states that, if a source cannot prove its 

entitlement to the affirmative defense, “appropriate penalties could be assessed in accordance with section 113 of the 

CAA (see also 40 CFR 22.27)” (76 FR 81347). The commenter argued that this does not answer the questions stated 

above. Therefore, the commenter concluded, the proposed rule is unclear on this key issue of what the affirmative 

defense is intended to cover.

137 See 76 FR 81347 (“In any judicial or administrative proceeding, the Administrator would be able to challenge the 

assertion of the affirmative defense....”) (emphasis added).

138 See proposed 40 CFR 63.456.
134

required to pay the citizen-plaintiff’s attorneys fees, even if the source successfully demonstrated 

that it otherwise qualified for the affirmative defense, then the affirmative defense would not 

accomplish EPA’s stated objective of providing relief in situations where the emission 

limitations cannot be met despite proper design and operation of process and control equipment.

Commenter 0162 contended that EPA has not addressed these and other apparent 

limitations and shortcomings of the affirmative defense, which make it an entirely inadequate 

substitute for setting MACT standards that include provisions for SSM events. The commenter 

also stated that EPA provided no analysis that would supersede its long-standing determination 

that it is not desirable to rely on enforcement, rather than regulatory language, to address the 

inability to comply with technology-based standards during SSM events (37 FR 17214, (Aug. 25, 

1972)) (establishing SSM provision in NSPS). The commenter noted that courts have adopted 

the same view. See, e.g., National Lime Ass’n, 627 F.2d at 431 n.46 (“the flexibility appropriate 

to enforcement will not render ‘achievable’ a standard which cannot be achieved on a regular 

basis, either for the reasons expressly taken into account in compliance determination regulations 

(here startup, shutdown and malfunction), or otherwise.”).139

Commenters 0162 and 0172 also stated that the provision needs to state clearly that a 

source that qualifies for the affirmative defense shall not be deemed to have violated the 

applicable standards during that time. Commenter 0162 suggested that EPA specifically reword 

the provision to state that a source “will not be deemed in violation of” the MACT standards for 

excess emissions or other deviations from the standards, associated with a startup, shutdown, or 

malfunction event, unless the event, and the source’s response to the event, do not meet the 

criteria spelled out in the regulations.”

140 If EPA did that, the commenter felt it may be 

unnecessary to state also that the affirmative defense relieves the source from liability for all 

types of penalties (civil penalties, civil administrative penalties, noncompliance penalties) and 

injunctive relief (save criminal penalties) in an action brought by EPA, a state, or a citizen-suit 

plaintiff. However, the commenter felt that should be the clear effect of qualifying for the 

affirmative defense. The commenter further suggested that this reconfigured provision be called 

something other than an “affirmative defense,” such as an “alternative standard for SSM events.”

Response: Based on Responses from Oil and Gas The EPA’s view is that the affirmative 

defense is consistent with CAA sections 113(e) and 304. Section 304 gives district courts 

jurisdiction “to apply appropriate civil penalties.” Section 113(e)(1) identifies the factors that the 

Administrator or a court shall take into consideration in determining the amount of a penalty to 

be assessed, only after it has been determined that a penalty is appropriate. The affirmative 

defense regulatory provision is not relevant to the amount of any penalty to be assessed under 

section 113(e) because if a court determines that the affirmative defense elements have been 

 

139 See 37 FR 17214 (Aug. 25, 1972) (establishing SSM provision in NSPS). See also Marathon Oil Co. v. EPA, 564 

F.2d at 1273 (explaining why EPA’s statement—that it would not take enforcement action against sources that 

exceeded effluent limitations because of upset events—was “not an adequate response” to the argument that 

standards that cannot be met during unavoidable upsets fail to reflect available technology). Commenter 0162 stated 

that, for these reasons, EPA’s statements in the proposal preamble—that it will “determine an appropriate response” 

to reported exceedances of the proposed standards, based on whether the exceedances were avoidable, minimized, 

etc. (which the commenter said seems to be in addition to providing the affirmative defense)—are not in any way a 

substitute for EPA setting the standards at an achievable level to begin with (76 FR 81347).

140 Compare, e.g., 40 CFR 80.613 (stating that persons demonstrating specified defenses “will not be

deemed in violation” and are not “deemed liable for a violation” of diesel fuel sulfur program regulations).
135

established, then a penalty is not appropriate, and penalty assessment pursuant to the section 

113(e)(1) factors does not occur.

In exercising its authority under section 112 to establish emission standards (at a level 

that meets the stringency requirements of section 112), the EPA necessarily defines conduct that 

constitutes a violation. The EPA’s view is that the affirmative defense is part of the emission 

standard and defines two categories of violation. If there is a violation of the emission standard 

and the source demonstrates that all the elements of the affirmative defense are met, only 

injunctive relief is available. All other violations of the emission standard are subject to 

injunctive relief and penalties. The CAA does not require that all violations be treated equally. 

Further, a citizen suit claim under section 304 allows citizens to commence a civil action against 

any person alleged to be in violation of “an emission standard or limitation under this chapter.” 

The CAA, however, allows the EPA to establish such “enforceable emission limitations.” Thus, 

the citizen suit provision clearly contemplates enforcement of the standards that are defined by 

the EPA. As a result, where the EPA defines its emissions limitations and enforcement measures 

to allow a source the opportunity to prove its entitlement to a lesser degree of violation (not 

subject to penalties) in narrow, specified circumstances, as the EPA did here, penalties are not 

“appropriate” under section 304.

The EPA’s view is that an affirmative defense to civil penalties for exceedances of 

applicable emission standards during periods of malfunction appropriately balances competing 

concerns. On the one hand, citizen enforcers are concerned about additional complications in 

their enforcement actions. On the other hand, industrial sources are concerned about being 

penalized for violations caused by malfunctions they could not have prevented and were 

otherwise appropriately handled (as reflected in the affirmative defense criteria). The EPA has 

used its section 301(a)(1) authority to issue regulations necessary to carry out the Act in a 

manner that appropriately balances these competing concerns.

Text from PSG The EPA agrees that affirmative defense is not a substitute for using 

malfunction emissions data in setting standards, because, as asserted in the proposal, the EPA is 

not obligated by the CAA to address malfunctions by incorporating emissions that result from 

malfunctions in setting the standards. The criteria for asserting affirmative defense bear no 

relationship to the factors for setting a MACT standard, because affirmative defense is not a 

condition for compliance, but rather a set of criteria for a source found to be in violation of a 

standard, to show that civil penalties are not appropriate in a given instance. Finally, the 

standards do represent emission limitations “achieved” by best-performing existing sources 

under CAA section 112(d)(3). What the standards do not represent, are standards achieved by 

sources operating while process, auxiliary, or control equipment is not operating, in partial or 

total failure due to malfunction, or when work practices are not being conducted properly.

The EPA reminds the commenter that EPA must establish emission standards that “limit 

the quantity, rate, or concentration of emissions of air pollutants on a continuous basis.” 

42 U.S.C. 7602(k) (defining “emission limitation and emission standard”). See generally Sierra 

Club v. EPA, 551 F.3d 1019, 1021 (D.C. Cir. 2008) (emissions limitations under CAA section 

112 must both continuously apply and meet section 112’s minimum stringency requirements, 

even during periods of SSM). Thus, the EPA is required to ensure that section 112 emissions 

limitations are continuous. The affirmative defense for malfunction events meets this 
136

requirement by ensuring that, even where there is a malfunction, the emission limitation is still 

continuous by being enforceable through injunctive relief.

The EPA’s objective in including affirmative defense as a facet of the standard is to 

provide relief from civil penalties for a class of violations where such penalties are not 

appropriate. Affirmative defense is not intended to relieve the owner/operator of the sanction of 

injunctive relief, or, as cited by the commenter, attorney fees, should a court find it appropriate to 

impose such a sanction.

Based on Response from Group I RTR draft p. 26 The affirmative defense applies to civil 

penalties, including civil administrative penalties and penalties under section 120, but does not 

apply to injunctive relief or criminal penalties. The affirmative defense is available in any civil 

action to enforce the standards set forth in this rule, whether such action is brought by EPA, a 

state or local authority or a citizen. The EPA agrees that, in some cases, injunctive relief may not 

be appropriate if all the criteria of the affirmative defense have been satisfied. In such cases, 

liability for attorney’s fees is not a real issue. However, some form of injunctive relief may be 

appropriate. The Sierra Club v. Otter Tail Power Co. case cited by the commenter is not on point 

and does not undermine EPA’s ability to limit the affirmative defense to penalty claims. The 

concurrent remedy doctrine provides that, where a party's legal remedies are time-barred, a 

party's concurrent equitable claims generally are barred. The affirmative defense is not a time-bar 

to civil penalties. EPA does not intend to provide an affirmative defense to criminal charges as 

the very nature of criminal charges is that there is alleged to be a knowing violation (CAA 

section 113(c)(1) through (3)), or a knowing or negligence release that threatens imminent 

danger to persons (CAA section 113(c)(4) and (5)). In these circumstances, it is likely that the 

source did not do all that could be done to prevent the excess emissions. However, if there are 

circumstances that justify a knowing release as is suggested by the commenter, such 

circumstances can be raised in any enforcement action and may be the basis for a defense

Text from PSG The EPA disagrees that no analysis has been presented to explain our 

approach to SSM and the role that affirmative defense plays in this approach. In the proposal 

notice cited by the commenter (37 FR 17214, (Aug. 25, 1972)), the EPA plainly stated the 

objective to create a process “by which sources whose emissions had exceeded the standards 

could seek to show why the excesses were excusable.” The EPA further elaborated that a formal 

process to do so was superior to an informal process, and that the formal process offered three 

critical advantages:

First, the existence of a formal process better informs the public of the policy and factual 

issues which will underlie enforcement of the standards. Second, affected industries 

which are making good-faith efforts to meet the standards will on the whole welcome a 

regularized means of informing the Agency in detail of the circumstances surrounding 

unavoidable emission excesses. Third, the Agency expects to benefit substantially from 

the information it will gain about the operation of the processes in question, for both 

future enforcement and standard setting.

We hasten to point out that, in response to comments on the approach proposed in that notice, the 

EPA modified the proposal and promulgated the exemption language subsequently found 

contrary to the statute in Sierra Club.
137

The approach that the EPA has proposed and promulgates now is similar to the approach 

outlined in the 1972 proposal, but which at that time was not promulgated at the final rule. The 

critical advantages cited in the 1972 proposal (for a formal process akin to affirmative defense) 

are all met by the formal process for asserting affirmative defense as explained by the current 

regulatory action. The key difference in the approach we are promulgating is that it does not 

suffer from the flaw of the proposal in 1972, or the exemptions that EPA eventually promulgated 

and became the object of Sierra Club: that the EPA does not have the authority to grant such 

exemptions.

91. Comment: Commenter 0160 expressed concern about how affirmative defense may be 

employed by the pulp and paper mills, specifically with respect to NCG venting from 

malfunctions regulated by §§63.443 and 64.446. The commenter noted that the venting 

allowances are cumulative during the reporting period and suggested that the 2-day notification 

and 45-day root cause analysis be submitted only after there is an actual exceedance of a 

percentage venting limit. The commenter expressed concern that mills may employ affirmative 

defense for every malfunction NCG venting as a preventative measure in case it were to exceed 

one of the percentage limits (1 percent, 4 percent, or 10 percent) and this could prove to be very 

burdensome to facilities and delegated state agencies. The commenter suggested that the 2-day

notification and 45-day root cause analysis be submitted only after there is an actual exceedance 

of a percentage venting limit. The commenter also suggested limiting the number of 2-day

affirmative defense notifications to ventings over two hours in length, or notifying for 

consolidated venting events after they add up to some threshold, such as 4 hours.

Commenter 0228 quoted §63.456(b) as follows regarding the affirmative defense 

reporting requirement in the proposed rule:

The owner or operator seeking to assert an affirmative defense shall also submit a written 

report to the Administrator within 45 days of the initial occurrence of the exceedance of 

the standard in paragraphs §§63.443(c) and (d), 63.444(b) and (c), 63.445(b) and (c), 

63.446(c), (d), and (e), 63.447(b) or §63.450(d) to demonstrate, with all necessary

supporting documentation, that it has met the requirements set forth in paragraph (a) of 

this section. The owner or operator may seek an extension of this deadline for up to 30 

additional days by submitting a written request to the Administrator before the expiration 

of the 45 day period. Until a request for an extension has been approved by the 

Administrator, the owner or operator is subject to the requirement to submit such report 

within 45 days of the initial occurrence of the exceedance.

Commenter 0228 noted that they require owners and operators to submit requests to 

exempt exceedances with their quarterly excess emission reports. These requests are typically

considered within 30 days of receipt of the excess emissions report. The proposed provision 

appears to create a duplicative process for request and consideration of excess emissions. This 

separate process would potentially require perpetual consideration of exemption requests, rather 

than conforming to the state's current practice of submitting all requests pertaining to that quarter 

with the regular quarterly report (due within 30 days after the end of the calendar quarter. The 

proposed provision would impose inefficiency on the current process by creating unnecessary

tracking and administrative work for both the facility and for state regulators. The commenter 
138

requested that the proposed provision be changed so that assertions of affirmative defense are

submitted on the same timeline as the quarterly excess emissions report.

Response: Concerning commenter 0228’s note that the proposed subpart S affirmative 

defense reporting requirements appear to create a duplicative process for request and 

consideration of excess emissions, we note that states can petition for delegation. A state’s 

affirmative defense requirements would have to be at least as stringent as EPA’s.

In response to the concerns noted by commenters 0160 and 0228 regarding the timing of 

submittal of the affirmative defense notifications and reports, we have changed the requirements 

in §63.456(b) of the final rule to read as follows:

... This affirmative defense report shall be included in the first periodic compliance, 

deviation report or excess emission report otherwise required after the initial occurrence 

of the violation of the relevant standard (which may be the end of any applicable

averaging period). If such compliance, deviation report or excess emission report is due 

less than 45 days after the initial occurrence of the violation, the affirmative defense 

report may be included in the second compliance, deviation report or excess emission 

report due after the initial occurrence of the violation of the relevant standard.

As noted in a later response, we have also eliminated the 2-day notification requirement 

that was included in §63.456(b) at proposal because we will receive sufficient notification of 

malfunction events that result in violations in other required compliance reports, such as the 

malfunction report required under §63.455(g).

Regarding commenter 0228’s concern about the proposed provisions creating the 

potential for perpetual consideration of exemption requests, we should note that affirmative 

defense is only available when a violation has occurred as a result of a malfunction; malfunctions 

themselves do not necessarily lead to violations. Furthermore, as defined in §63.456(a)(1)(i), 

affirmative defense was explicitly not designed for use with frequent events or as a preventative 

measure in anticipation of a violation, per the scenario described by commenter 0228.

92. Comment: According to commenter 0163, EPA acknowledges that malfunction periods 

are “sudden, infrequent, and not reasonably preventable failure of air pollution control and 

monitoring equipment, process equipment or a process to operate in a normal or usual manner”

and argues that the CAA does not require them to include malfunction periods in development of 

MACT emission standards. [76 FR 81346] The commenter stated that, rather than structure a 

discrete and achievable emissions standard for malfunction events, the EPA places them in a 

netherworld where the emission limitations otherwise applicable during normal operating 

conditions may or may not be enforced depending on how well a facility meets, in EPA’s eyes, a 

very broad set of conditions. The commenter noted that EPA provides an “affirmative defense” 

provision against civil penalties that requires a “preponderance” of evidence to support. [76 FR 

81347]

Response: We acknowledge the commenter’s statement concerning malfunction events

and refer the commenter to other responses in this section concerning our approach on SSM and 

affirmative defense for the final rule (e.g., responses to comment nos. 86 and 90).
139

93. Comment: Commenter 0218 maintained that the proposed affirmative defense from civil 

penalties for malfunctions is unlawful, and creates a new loophole that will reduce the deterrent 

impact of the proposed standards. The commenter argued that Congress plainly intended citizens 

to be able to enforce emission standards under the CAA using the full range of civil enforcement 

mechanisms available to the government, and, in the HAP context, subject only to the limitation 

that government not be “diligently prosecuting” its own civil enforcement action, according to 

CAA section 304(b)(1)(B) and 42 U.S.C. 7604(b)(1)(B).

The commenter stated that the EPA exceeded its authority by attempting to impose 

additional Agency-created limits on civil penalties, when the CAA spells out the only limits that 

Congress intended to impose on citizens’ ability to seek and recover penalties in enforcement 

suits under CAA section 304, 42 U.S.C. 7604.320.

The commenter stated that the proposed affirmative defense goes directly against 

Congressional intent that judges should determine the size of civil penalties whenever they are 

sought, and that the proposal will impermissibly chill citizen participation and the ability to win 

an effective, deterrent remedy in CAA enforcement actions.

The commenter observed that the CAA gives the EPA minimal discretion that only

applies to administrative penalties which may be imposed under subsection 113(d), but no 

authority to EPA to compromise, modify or limit civil penalties that a court may impose under 

section 113(e) or section 304. The commenter emphasized that the explicit reference to EPA’s

ability to modify penalties in one subsection and its absence in the other subsection of the same 

provision can only be understood as an intentional decision by Congress, which EPA may not 

contravene by rule.141

The commenter argued that the owner of a facility may be able to evade civil penalties 

after being sued by a community group for a violation of emission standards, if the owner 

satisfied the requirements set forth in EPA’s proposed affirmative defense regulations. 

The commenter stated that it is improper for a court to fail to consider these factors, or to 

fail to make its own determination of what civil penalties are “appropriate” under CAA section 

304(a), and EPA should not ask a court to ignore its legal duty. The commenter observed that it 

is also improper for EPA to fail to consider the section 113(e)(1) factors in situations in which it 

 

141See 42 U.S.C. 7413(e) (listing factors). Note that the proposed exemption would also be barred under Chevron

step two or found to be arbitrary and capricious since, even if there exists some slight ambiguity, it is unreasonable 

to construe the statute as permitting EPA to short-circuit the consideration of specifically listed factors. See 

Chevron, 467 U.S. at 843 (explaining that if the statute does not answer the question at issue, “the question for the 

court is whether the agency’s answer is based on a permissible construction of the statute”); S. Coast Air Quality 

Mgmt. Dist. v. EPA, 472 F.3d 882, 895 (D.C. Cir. 2006) (“We further hold that EPA’s interpretation of the Act in a 

manner to maximize its own discretion is unreasonable because the clear intent of Congress in enacting the 1990 

Amendments was to the contrary.”); see also Gen. Instrument Corp. v. F.C.C., 213 F.3d 724, 732 (D.C. Cir. 2000) 

(explaining that “an arbitrary and capricious claim and a Chevron step two argument overlap”); Motor Vehicle Mfrs. 

Ass‘n of U.S., Inc. v. State Farm Mut. Auto. Ins. Co., 463 U.S. 29, 43 (1983) (explaining that agency acts in arbitrary 

and capricious manner if it fails to consider “relevant factors” or “entirely fail[s] to consider an important aspect of 

the problem”). By “upset[ting] the statutory balance struck by Congress,” as discussed above, the affirmative 

defense is unreasonable under Chevron step two. Int‘l Alliance of Theatrical & Stage Employees v. N.L.R.B, 334 

F.3d 27, 35 (D.C. Cir. 2003).
140

is setting the penalty. CAA section 113(e)(1); 42 U.S.C. 7413(e)(1); see also N.Y. Cross Harbor 

R.R. v. Surface Transp. Bd., 374 F.3d 1177, 1184 (D.C. Cir. 2004). It is impermissible for EPA 

to attempt to displace those factors or in any way alter their significance by creating a bar to 

penalties if certain Agency-defined considerations are met instead.

The commenter asserted that the burden the affirmative defense places on citizens makes 

it less likely that they will enforce the Act, that citizen participation in CAA enforcement will be 

hindered, in violation of citizens‘ rights to protect themselves from pollution and in direct 

conflict with congressional intent. The commenter also noted that several of the factors at issue 

in the affirmative defense undercut Congress’ intent that citizen suit enforcement should avoid 

re-delving into “technological or other considerations.” (NRDC v. Train, 510 F.2d 692, 724 

(D.C. Cir. 1974) The commenter stated that the affirmative defense imposes a technical burden 

on citizens, and the burden renders the defense impermissible. The commenter predicted that the 

affirmative defense would likely be used on a routine basis by polluters seeking to avoid 

penalties, just as the malfunction exemption was, and enforcement of the Act could suffer.

The commenter expressed concern that the new “affirmative defense” may make it more 

likely that malfunctions happen, by giving industry a way to evade penalties, if facilities can 

show a violation was due to a malfunction.

The commenter argued that, if the EPA had authority to promulgate any type of affirmative 

defense to penalties for malfunctions, EPA should also promulgate the following provisions, and 

also must promulgate strong reporting, monitoring, and other compliance requirements (in 

separate comments):

 A specific amount of compensatory penalties should apply to each reported malfunction 

(consistent with the Act). These funds should be dedicated to enforcement, inspections, 

and monitoring in the local community around the specific facility, to create greater 

assurance that malfunctions will not happen again.

 The EPA must modify the regulations so that a facility or company cannot use the 

affirmative defense more than once within a set period of time, such as 10 years. The 

affirmative defense should become automatically unavailable to a facility that has 

previously had a malfunction within the last 10 years, to ensure that this defense does not 

swallow the value of the standards.

The commenter concluded that the EPA must work to expand and protect the ability of 

people harmed by air pollution to seek all appropriate and available forms of relief in court.

Response: Based on Response from Oil & Gas: The EPA’s view is that the affirmative 

defense is consistent with CAA sections 113(e) and 304. Section 304 gives district courts

jurisdiction “to apply appropriate civil penalties.” Section 113(e)(1) identifies the factors that the 

Administrator or a court shall take into consideration in determining the amount of a penalty to 

be assessed, only after it has been determined that a penalty is appropriate. The affirmative 

defense regulatory provision is not relevant to the amount of any penalty to be assessed under 

section 113(e), because if a court determines that the affirmative defense elements have been 

established, then a penalty is not appropriate, and penalty assessment pursuant to the section 

113(e)(1) factors does not occur.
141

In exercising its authority under section 112 to establish emission standards (at a level 

that meets the stringency requirements of section 112), the EPA necessarily defines conduct that 

constitutes a violation. The EPA’s view is that the affirmative defense is part of the emission 

standard and defines two categories of violation. If there is a violation of the emission standard 

and the source demonstrates that all the elements of the affirmative defense are met, only 

injunctive relief is available. All other violations of the emission standard are subject to 

injunctive relief and penalties. The CAA does not require that all violations be treated equally. 

Further, a citizen suit claim under section 304 allows citizens to commence a civil action against 

any person alleged to be in violation of “an emission standard or limitation under this chapter.” 

The CAA, however, allows the EPA to establish such “enforceable emission limitations.” Thus, 

the citizen suit provision clearly contemplates enforcement of the standards that are defined by 

the EPA. As a result, where the EPA defines its emissions limitations and enforcement measures 

to allow a source the opportunity to prove its entitlement to a lesser degree of violation (not 

subject to penalties) in narrow, specified circumstances, as the EPA did here, penalties are not 

“appropriate” under section 304.

The EPA’s view is that an affirmative defense to civil penalties for exceedances of 

applicable emission standards during periods of malfunction appropriately balances competing 

concerns. On the one hand, citizen enforcers are concerned about additional complications in 

their enforcement actions. On the other hand, industrial sources are concerned about being 

penalized for violations caused by malfunctions that could not have prevented and were 

otherwise appropriately handled (as reflected in the affirmative defense criteria). The EPA has 

used its section 301(a)(1) authority to issue regulations necessary to carry out the Act in a 

manner that appropriately balances these competing concerns.

The EPA disagrees that the affirmative defense provision will hamper citizen 

enforcement. First, injunctive relief is still available, and the threat of penalties would not deter 

violations in cases where all of the conditions of the affirmative defense have been satisfied,

because the affirmative defense criteria ensure that all reasonable steps were taken to prevent a 

malfunction that causes excess emissions.

Further, litigating whether a source has met the affirmative defense will not burden 

citizen groups any more or less than would litigating the appropriate penalty amount in the 

penalty assessment stage of a citizen suit enforcement action, because the section 113(e) penalty

assessment criteria and the affirmative defense criteria are similar and, in fact, overlap. For 

example, the requirement that the Administrator or the court consider “good faith efforts to 

comply” is bound to generate the type of fact-intensive disputes of which the commenter 

complains. In addition, several of the affirmative defense criteria are exactly the type of criteria 

the Administrator or a court might consider in determining whether a source made “good faith 

efforts to comply.” For example, to take advantage of the affirmative defense, the source must 

prove by a preponderance of the evidence that, among other things, the excess emissions “were 

caused by an unavoidable failure of air pollution control and monitoring equipment, process 

equipment, or a process to operate in a normal or usual manner” and “could not have been 

prevented through careful planning, proper design or better operation and maintenance practices” 

and “did not stem from any activity or event that could have been foreseen and avoided, or 

planned for.”
142

Thus, the EPA does not expect the affirmative defense provision to significantly alter the 

burden of bringing a citizen enforcement action. For those cases that do proceed to trial, even in 

the absence of this affirmative defense, sources generally raise equitable arguments to argue for a 

low penalty, and citizens often rebut such arguments. Therefore, as a practical matter, the EPA 

does not expect the affirmative defense provision to materially affect the practice of CAA 

enforcement.

The EPA is not adopting the commenter’s suggestion with respect to compensatory

damages or limits on the frequency of use of the affirmative defense. It is not clear that the EPA 

has authority to require the automatic imposition of compensatory damages, and even if such 

authority exists, the EPA does not think automatic imposition of damages is appropriate, as it 

would unduly complicate the enforcement process. Ensuring that malfunctions do not recur can 

be handled through imposition of appropriate injunctive relief. In addition, the EPA’s view is 

that it would not be appropriate to limit a source’s ability to take advantage of the affirmative 

defense to one time over a specified period of time such as 10 years, given that the affirmative 

defense is only available when the source could not have prevented the excess emissions. With 

respect to the commenter’s suggested reporting requirements, the reporting requirements in the 

rule being promulgated already require malfunction reporting, and the affirmative defense 

provisions require that parties choosing to assert the affirmative defense meet additional 

malfunction reporting requirements. Any such reports submitted to the EPA are publicly 

available pursuant to CAA section 114.

94. Comment: Definition of Malfunction. Commenter 0168 noted the language that EPA 

proposed for defining malfunction in §63.456(a)(1) is similar to the definition in §63.2, with one 

major exception. In the proposed language, one of the conditions for an affirmative defense is 

that the excessive emissions were caused by a “sudden, infrequent, and unavoidable failure...” 

The GP definition of malfunction uses the phrase “not reasonably preventable” instead of the 

word “unavoidable.” The commenter believes that this creates two different definitions of 

malfunction. The commenter saw no reason for two different definitions of a malfunction and 

requested that the Agency revise the proposed language to reflect the GP definition of a 

malfunction.

Response: Based on Response from Nitric Acid The EPA disagrees that the criteria of the 

affirmative defense changes the definition of malfunction (as defined in §63.2) for purposes of 

the NESHAP program. The wording difference between the §63.456(a)(1) and the §63.2

malfunction definitions is because the EPA does not intend that the affirmative defense be 

available in every instance of a malfunction.

95. Comment: Root Cause Analysis Definition. Commenter 0168 noted that the term “root 

cause analysis” implies a specific formal process, and there are several techniques that may be 

called “root cause analysis,” depending on the author and industry. For many malfunctions, the 

cause is immediately obvious, and a formal process for determining the cause is not needed. 

When a malfunction occurs, the expectation is that the facility will correct the problem as 

quickly as possible and return to their operating window. A formal root cause analysis is 

typically limited to very significant events or repeat events. The proposed language assumes that 

all malfunctions are equally significant and need an identical degree of investigation. The 
143

commenter asserted that a formal root cause analysis should only be used when other reasonable 

methods fail to show what caused the malfunction or when the serious nature of an event might 

make such an analysis necessary. Moreover, other tools may be more appropriate (e.g., failure 

mode and effect, fault tree, etc.), or more powerful tools may be introduced in the future. The 

facility is the only one that can and should decide what tool to use to determine the cause of the 

malfunction.

If EPA intends for the facility to investigate and fix the source of the malfunction so that 

it is less likely to recur, the commenter supported that concept, but suggested that EPA use a 

term other than “root cause analysis” that does not carry a specific meaning. However, if the 

Agency envisions a formal process for determining the root cause for every malfunction, no matter 

how simple, the commenter asserted that this is unnecessary and would result in excess efforts with 

no environmental gains.

Response: Based on Response from MATS p. 59 In the context of this rule, the term “root 

cause analysis” was used generically to imply an analysis of sufficient depth and complexity to 

indicate whether a malfunction did indeed cause a failure to meet a standard, provide sufficient 

information on the nature and cause of a malfunction to determine whether the source had a 

malfunction that met the definition of a malfunction, and whether civil penalties are an 

appropriate sanction for the violation if one occurred. The term “root cause analysis” is not 

defined in subpart A (the GP) or in the subpart being promulgated, subpart S. The EPA did not 

intend to prescribe a specific methodology, given that “root cause analysis” is not a defined term 

in the applicable subparts of part 63.

While conducting an analysis of every malfunction may be a “best practice,” for 

regulatory purposes, an analysis is only required for those malfunctions for which the source 

chooses to assert an affirmative defense, and not every malfunction is significant enough to 

warrant the assertion. The EPA believes that sources seeking to minimize emissions will 

endeavor to determine what went wrong anytime there is a minor or major malfunction, and the 

facility should decide what level of investigation is needed in each instance. We agree with the 

commenter that sources should use appropriate techniques of analysis to achieve the desired 

results and conclusions in the event of a malfunction. The EPA joins the commenter in seeking 

meaningful results which successfully identify, and address the cause of the malfunction.

The EPA believes that a minor administrative burden will result in sources analyzing 

their violative emissions to reduce or avoid those emissions in the future, which is an 

environmental benefit. The EPA is revising the root cause analysis requirement to clarify that the 

purpose of the root cause analysis is to determine, correct, and eliminate the primary cause of the 

malfunction and that the root cause analysis itself does not necessarily require that the cause be 

determined, corrected or eliminated. However, in most cases, EPA believes that a properly 

conducted root cause analysis will have such results. Such an analysis is beneficial in resolving 

or preventing violations and excess emissions whether the source seeks to assert the affirmative 

defense or not. A root cause analysis is one example of what constitutes good air pollution 

control practices to minimize emissions.

96. Comment: Rebuttable Presumption Commenters 0168, 0164, and 0207 suggested that 

EPA should modify the affirmative defense provisions so that it is a “rebuttable presumption.” 
144

As EPA knows, malfunctions will occur. Even the best run facilities will have circumstances 

where events happen that are out of their control. While the commenters asserted that EPA must 

take into account the conditions that occur during malfunctions and establish limits that consider 

these circumstances, they also agreed that some form of enforcement discretion is needed for 

malfunctions. The commenters expressed support for EPA to maintain a regulatory provision for 

malfunctions. However, the commenters 0163, 0164, 0168, and 0207 were concerned that 

allowing a facility to interpose an affirmative defense for violations caused by malfunctions 

implies that the facility is guilty until proven innocent and improperly shifts the burden to the 

facility. Therefore, commenter 0168 suggested that EPA establish a rebuttable presumption 

(rather than affirmative defense), where it is presumed that any violation occurring during the 

malfunction was not the facility’s fault unless the Agency proves certain facts that are 

enumerated in the rules. This will allow the Agency to challenge the alleged deviation without 

compromising the legal rights of either party.

According to commenter 0162, even if the proposed affirmative defense was not 

unreasonably restrictive, being able to assert a defense obviously is not the same as complying 

with emission limitations that are properly set in accordance with CAA section 112. The 

commenter noted that, even though a source believes it qualifies for the affirmative defense, it 

may be considered to have violated the standards—and may have to report violations, certify

noncompliance, etc.—until there has been an enforcement proceeding, and the source has 

successfully asserted the affirmative defense. Commenter 0162 argued that the affirmative 

defense places the source in the position of proving its innocence, rather than EPA or another 

enforcement authority having to prove that the source violated the CAA.

Commenter 0162 contended that EPA, in this instance, has not provided any statutory

authority, nor any real justification, for requiring a source to prove its innocence, including fully

demonstrating its innocence within 45 days of the event, without even being charged. In the

event EPA adopts an approach like the proposed affirmative defense, the commenter suggested it 

include these terms: “Once a source has claimed that its excess emissions were related to a 

malfunction, it should not be considered to be in violation of the standards unless the 

enforcement authority demonstrates that the source is not entitled to claim the malfunction.”

Response: Based on Response from MATS p. 55, Shipbuilding/Wood Furniture p. 24 The 

EPA does not agree with the commenters’ requested approaches regarding affirmative defense. 

The “rebuttable presumption” approach requested by commenters 0168, 0164, and 0207 would 

shift the burden of proof from the source to the EPA, as would the similar approach requested by 

commenter 0162 to state the affirmative defense in terms that, once a source has claimed that its 

excess emissions were related to a malfunction, it will not be considered to be in violation of the 

standards unless the enforcement authority demonstrates that the source is not entitled to claim 

the malfunction. It is the source, not the EPA, which has the relevant information to assess 

whether a particular event qualifies as a malfunction and meets the affirmative defense.

Furthermore, the commenters’ requested approaches appear to be similar to the scheme that the 

D.C. Circuit Court vacated in the Sierra Club case, in that there would be no violation unless the 

enforcing party (EPA or a citizen), established that the event in question was not a malfunction.

The EPA also disagrees with comments that criticize the affirmative defense for shifting 

the burden of proof. The affirmative defense does not require a facility to prove its innocence 
145

rather than requiring an enforcement authority to prove a violation of the CAA or change the 

burden of proof with respect to establishing a violation. The affirmative defense applies to 

penalties and, thus, is only used where a violation has been established. The burden of proof 

remains with the plaintiff in an enforcement action. See, e.g., §22.24. If a violation has been 

established and a source wishes to assert the affirmative defense with respect to penalties, the 

source does bear the burden of establishing that the elements of the affirmative defense have 

been met. This burden-shifting is appropriate because the source is in a better position to 

determine the facts required to establish the defense. See, e.g., Arizona Pub. Serv. Co. v. EPA,

562 F.3d 1116, 1120, 1129-30 (10th Cir. 2009) (rejecting industry challenge to the EPA’s use of 

an affirmative defense to address excess emissions during malfunction events).

In exercising its authority under section 112 to establish emission standards (at a level 

that meets the stringency requirements of section 112), EPA necessarily defines conduct that 

constitutes a violation. The EPA’s view is that the affirmative defense is part of the emission 

standard and defines two categories of violation. If there is a violation of the emission standard 

and the source demonstrates that all the elements of the affirmative defense are met, only 

injunctive relief is available. All other violations of the emission standard are subject to 

injunctive relief and penalties.

In response to commenter 0162’s concern about the rule “requiring a source to prove its 

innocence, including fully demonstrating its innocence within 45 days of the event,” as noted in 

the following response, we have revised the 45-day affirmative defense reporting requirement to 

require sources to submit the affirmative defense report with the next compliance report.

97. Comment: Immediate Notification. Commenter 0168 referenced a recently proposed rule 

(77 FR 4522, 4538, January 30, 2012), in which EPA proposed dropping the immediate 

notification process and simply requiring a written report within 45 days of the malfunction. The

commenter suggested that the Agency adopt the same change in the pulp and paper regulation. 

Commenter 0162 also noted that EPA recently proposed almost identical affirmative defense 

requirements in its proposed reconsideration of various provisions of the Chemical 

Manufacturing Area Source Rule (77 FR 4522, January 30, 2012), but omitted the 2-day

notification requirement. The commenter hoped that this indicates that EPA has been persuaded 

by comments submitted by the SSM Coalition (of which commenter 0162 is a member) and 

others that the 2-day notification requirement is onerous and burdensome. Commenter 0162 

requested that, at a minimum, EPA abandon the 2-day notification requirement in the final pulp 

and paper RTR rule, consistent with its proposed provisions for the Chemical Manufacturing 

Area Source Rule.

Response: Based on Response from Oil and Gas The EPA has evaluated some of the 

affirmative defense criteria, and is revising both the immediate notification and 45-day

malfunction report. The EPA has removed the requirements to notify the EPA within 2 days of 

violation of a standard in order to be able to avail themselves to a claim for affirmative defense 

and instead requires that the affirmative defense report be included in the first the first periodic 

compliance, deviation report or excess emission report otherwise required after the initial 

occurrence of the violation of the relevant standard (which may be the end of any applicable 

averaging period). If such compliance, deviation report or excess emission report is due less than 

45 days after the initial occurrence of the violation, the affirmative defense report may be 
146

included in the second compliance, deviation report or excess emission report due after the initial 

occurrence of the violation of the relevant standard.

98. Comment: 45-Day Report Period. Commenter 0162 described as unreasonable the 

provision allowing sources only 45 days to provide the extensive documentation required by the 

affirmative defense as currently written, including a completed root cause analysis. The 

commenter further described as unnecessary and burdensome EPA’s “guilty until proven 

innocent” approach of requiring complete documentation that an event qualifies for the 

affirmative defense at the time of the event. According to the commenter, if EPA persisted in 

requiring such reporting, 90 days is the minimum time that should be allowed for the written 

report, unless EPA substantially streamlines the criteria for the affirmative defense, consistent 

with their comments.

Commenter 0162 noted several problems with the proposed 45-day period for submitting 

a written report demonstrating that the source qualifies for the affirmative defense, a period 

which commences on the date of “the initial occurrence of the exceedance of the standards” (see 

proposed §63.456(b)). According to the commenter, much of the required content of that written 

report could not be created until the malfunction event ceased—which the commenter indicated 

could be many days after the malfunction commenced. As an example, the commenter noted that 

if a biological wastewater treatment system stopped providing sufficient HAP removal 

efficiency, it could take days to identify the nature of the problem and weeks to reestablish a 

sufficient microorganism community to again meet treatment requirements. The commenter 

pointed out that this could give the source much less than 45 days, in practice, to prepare the 

report.

According to commenter 0162, the provision in the proposed rule for requesting and 

obtaining an extension of the reporting deadline of up to 30 days would provide little practical 

relief. The commenter noted that the source would have to submit the report within 45 days 

unless the EPA Administrator (or his or her authorized representative, see §60.2) granted the 

extension request before the expiration of the initial 45-day period, which the commenter said is 

not likely to happen until shortly before, if not after, the report would otherwise be due. At a 

minimum, the commenter recommended that the rule provide that a request for extension of the 

reporting deadline be considered granted if EPA has not acted on it within 10 days.

Because of the problems commenter 0162 described above regarding the timing of 

required reporting, the commenter requested that malfunction reporting be required on a semiannual basis for malfunctions that occurred during the preceding 6 months (the same frequency

as similar reports pursuant to NESHAP and Title V permit requirements). The commenter stated 

that this would enable EPA to review the source’s compliance history and the measures being 

taken to address malfunctions, without imposing unworkable reporting deadlines (or potentially

encouraging sources to bombard EPA with reports for malfunctions that may not ultimately 

result in the source exceeding the 30-day average emission limitation). According to the 

commenter, there is no indication anywhere that EPA has justified departing from its conclusion 

that semi-annual reporting of malfunctions is sufficient, as reflected in the current subpart S 

standards (see §63.455(a)).
147

Response: Based on Response from Oil & Gas The EPA has evaluated some of the 

affirmative defense criteria, and is revising both the immediate notification and 45-day

malfunction report. Instead, the final rule allows owners or operators seeking to assert an 

affirmative defense to demonstrate, with all necessary supporting documentation (as was 

required under the proposed 45-day report), that it has met the affirmative defense criteria by

submittal of the affirmative defense report in the first periodic compliance, deviation report, or 

excess emission report otherwise required after the initial occurrence of the violation of the 

relevant standard (which may be the end of any applicable averaging period). If such 

compliance, deviation report, or excess emission report is due less than 45 days after the initial 

occurrence of the violation, the affirmative defense report may be included in the second 

compliance, deviation report, or excess emission report due after the initial occurrence of the 

violation of the relevant standard. This change provides sources with sufficient time to 

demonstrate that they have met the required affirmative defense criteria. 

99. Comment: Electronic Communication. Commenter 0168 stated that EPA should allow 

notification by e-mail or other electronic means. As facilities and EPA move toward electronic 

recordkeeping, it makes no sense to require keeping a “properly signed, contemporaneous 

operating logs” as a requirement for an affirmative defense. As such, the commenter suggested

modifying this provision. In addition, it is impossible to eliminate the causes for certain 

malfunctions (e.g., lightning strikes).

In a similar comment, commenter 0228 quoted §63.456(b) as follows:

The owner or operator of the affected source experiencing an exceedance of its emission 

limit(s) during a malfunction shall notify the Administrator by telephone or facsimile

(FAX) transmission as soon as possible, but no later than two business days after the 

initial occurrence of the malfunction, if it wishes to avail itself of an affirmative defense 

to civil penalties for that malfunction.

Commenter 0228 suggested that this section be changed so that EPA broadens its 

communication options to include electronic media such as e-mail to be used when the facility

contacts the Administrator. The commenter’s state compliance staff sometimes requests 

submittal of the 48-hour notification via e-mail rather than by fax or telephone. In cases where 

telephone is more expeditious or there is cause for discussion, the regulatory agency might ask 

the owner or operator to follow up the phone call with a written form sent via e-mail.

Response: Based on Response from Shipbuilding/Wood Furniture p. 25 The EPA 

generally accepts documents in electronic format, as long as the format is compatible with the 

requirements of the standards. For the affirmative defense provisions, the owner or operator of a 

facility experiencing an exceedance of its emission limit(s) during a malfunction must notify the 

Administrator by telephone or fax transmission of the exceedance. However, the written reports 

required to demonstrate that the affirmative defense provisions have been met. In the case of 

signed logs, the EPA accepts electronically signed operating logs, where the format and method 

of submission meets the regulatory criteria and are compatible with the EPA’s and the delegated 

authorities’ electronic submission systems. Any source submitting records electronically should 

exercise due diligence to assure receipt by the EPA and the delegated authority.
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100. Comment: Affirmative Defense Language. Commenter 0168 suggested that EPA clarify

its affirmative defense provisions. While the commenter preferred that EPA use a rebuttable 

presumption, should the Agency keep the affirmative defense concept, the commenter suggested 

the following modifications to the language to make it more usable. The commenter understood

that most of the provisions EPA proposed for the affirmative defense came from earlier guidance 

memos. While these provisions were in guidance, the Agency did not need to be careful of the 

wording, since they were only guidance and did not have the weight of regulation. However, if 

the Agency wants to codify this guidance into regulatory language, several changes are needed. 

For example, EPA should drop the reference to “any” activity in this section. There are also 

several references to “All” that would make it difficult to satisfy the requirements of an 

affirmative defense. In addition, the language in the provision is contradictory. In paragraph (a), 

the phrase “preponderance of evidence” is used, while later in that paragraph (iii), the language 

refers to “any activity,” meaning that more than preponderance of evidence is needed. This same 

trend occurs in paragraphs (5) “All possible,” (6) “All,” (7) “All of the actions,” and (8) “At all 

times.” While “all” would include “preponderance,” “preponderance” does not mean all of the 

time. The commenter suggested that the phrase “preponderance of evidence” is adequate and the 

references to “all” and “any” in the later paragraphs should be modified.

Commenter 0162 argued that the proposed affirmative defense as written was 

unreasonable and impracticable. According to the commenter, many aspects of the affirmative 

defense would make it unavailable as a practical matter for many, if not most, malfunctions. The 

commenter said that EPA needed to substantially revise and streamline the proposed affirmative 

defense for it to be of practical value. Commenter 0162 stated that the affirmative defense 

provision in proposed §63.456(a) lists numerous conditions that the commenter said may be 

appropriate in determining whether excess emissions during a malfunction should be considered 

a violation, but ought not be listed as mandatory criteria, all of which a source has to meet to 

even raise an affirmative defense. As an example, the commenter cited proposed 

§63.456(a)(1)(i), which requires that, to establish an affirmative defense, the source must prove 

that the excess emissions were “caused by a sudden, infrequent, and unavoidable failure of air 

pollution control and monitoring equipment, process equipment, or a process to operate in a 

normal or usual manner....” According to the commenter, there is no apparent reason why a 

“sudden” and “unavoidable” equipment failure or process upset leading to emissions greater than 

the MACT emission limitation should be considered a violation of the standards if it is not 

“infrequent,” even though it is “not part of a recurring pattern indicative of inadequate design, 

operation, or maintenance” and “[c]ould not have been prevented through careful planning, 

proper design or better operation and maintenance practices” (proposed §63.456(a)(1)(ii)&(iv)).

Commenter 0162 also noted that a number of the conditions for establishing an 

affirmative defense use phrases that are subject to a wide range of interpretations and do not 

appear reasonable or cost-effective. The commenter inquired how an enforcement authority or 

judge could determine whether “proper design” or “better operation and maintenance practices” 

could have prevented a malfunction (§63.456 (a)(1)(ii)), whether a recurring malfunction is a 

result of “inadequate design” (§63.456(a)(1)(iv)), whether repairs were made “as expeditiously

as possible” (§63.456(a)(2)), whether the source took “all possible steps” to minimize the impact 

of the excess emissions (§63.456(a)(5)), and whether emissions control systems “were kept in 

operation if at all possible”(§63.456(a)(6)).
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Commenter 0162 acknowledged that, in some cases, it may have been possible to prevent 

the malfunction or further reduced the excess emissions if the source had spent huge amounts of 

money with little emission reduction or had imposed economically impracticable constraints on 

its operation. According to the commenter, the affirmative defense, as proposed, leaves open the 

possibility that a source will be considered to be in violation because the enforcement authority

decides subjectively that, in one or more respects, it would have been “proper” or “possible” for 

the source to take further steps to prevent or minimize the malfunction.142 In effect, the 

commenter contended, EPA or the court may impose an extreme version of MACT during 

malfunction periods, without any application of the beyond-the-floor factors in CAA section 

112(d)(2). The commenter argued that, at a minimum, the vague and unqualified descriptors in 

the criteria for demonstrating the affirmative defense will inevitably lead to varying conclusions 

as to whether a violation has occurred, resulting in inconsistency from one jurisdiction to the 

next.

Commenter 0162 objected to the language in proposed §63.456(a)(6), which requires, as 

a condition for the affirmative defense, that all emissions “control systems were kept in operation 

if at all possible.” The commenter argued that the phrase “if at all possible” should not be used 

because it is an extreme term that bears no relation to good air pollution control practices. The 

commenter also indicated that this provision should be qualified, as the commenter said EPA has 

qualified similar provisions in the NESHAP GP in §63.6. As an example, the commenter said 

these conditions should be qualified with caveats that the operation must be consistent with 

safety and good air pollution control practices, that it does not require the source to make further 

efforts to reduce emissions below what the standards require, and that it does not require regular 

operation of backup or standby pollution control equipment.143 The commenter noted that that 

EPA has long recognized, in the NSPS GP, that it is appropriate to require sources to operate the 

affected facility and related air pollution control technology “to the extent 

practicable...consistent with good air pollution control practice for minimizing emissions” 

during SSM periods, not “if at all possible” (see §60.11(d); see also, e.g., §63.480(j)(4) (during 

SSM events, Group I Polymer & Resin plants are required to use “to the extent reasonably 

available, measures to prevent or minimize excess emissions to the extent practical.”)). 

Commenter 0162 argued that EPA cannot abandon those rational approaches and adopt the kind 

of absolute requirements implied by the proposed rule, without an explanation of why it is 

necessary and appropriate to do so. The commenter pointed out that EPA recently agreed to 

insert language in several NESHAPs to clarify that the general duty to minimize emissions “does 

not require the owner or operator to make any further efforts to reduce emissions if levels 

required by this standard have been achieved” (76 FR 22566, 22583, col. 3 (April 21, 2011)).

According to commenter 0162, proposed §63.456(a)(4) would preclude a facility from 

taking advantage of the affirmative defense if the malfunction involved bypassing control 

equipment or a process and the bypass was not “unavoidable to prevent loss of life, severe 

personal injury, or severe property damage.” The commenter asserted that this language is stated 

in such strong terms that it may be difficult or impossible for a source to demonstrate that it 

 

142 In contrast, commenter 0162 noted, EPA has included provisions in other NESHAPs explicitly recognizing that 

back-up control devices are not required. See, e.g., 40 CFR 63.480(j) (“Back-up control devices are not required, but 

may be used if available.”).

143 According to commenter 0162, EPA also determined it was appropriate to include those kinds of caveats in its 

regulation requiring proper operation and maintenance of wastewater treatment facilities, in 40 CFR 122.41(e).
150

meets this criterion, even though bypassing the control equipment or the process was an 

appropriate exercise of good air pollution control practices. The commenter cited an example 

that a bypass can constitute the best air pollution control practice in response to an upset in order 

to prevent excess emissions (e.g., to avoid fouling of pollution control equipment media that in 

turn would result in reduced pollution control equipment efficiency or increased pollution control 

equipment downtime). The commenter further noted that there can be substantial room for 

disagreement about what constitutes “severe” property damage. The commenter also inquired 

about the degree of injury to employees that the bypass must avoid in order to qualify as 

avoiding “severe” personal injury. According to the commenter, besides the unclear and 

subjective nature of these criteria, there is nothing inherent to section 112 standards that requires 

a source to avoid bypassing control equipment to such a degree. Lastly, the commenter argued 

that it is not apparent, and that EPA has not attempted to explain, why the CAA would not allow 

bypassing “a process” in this way.

Commenter 0162 also objected to the language in proposed §63.456(a)(5), under which a 

source claiming the affirmative defense must prove that: “All possible steps were taken to 

minimize the impact of the excess emissions on ambient air quality, the environment and human 

health.” In addition to objecting to the subjective term “all possible steps,” the commenter also 

objected to the disconnect in this provision between the absolute and extreme requirement of the 

affirmative defense and the provisions of the CAA designed to attain ambient air quality

standards and protect human health and the environment. According to the commenter, the CAA 

does not require sources to take “all possible steps” to control emissions, even to minimize the 

impact of hazardous air pollutant emissions on human health under CAA section 112(f). In 

addition, the commenter indicated that it is unclear how this criterion for qualifying for the 

affirmative defense differs from proposed §63.456(a)(3), which requires that the frequency, 

amount, and duration of excess emissions “were minimized to the maximum extent practicable.” 

The commenter recommended that §63.456(a)(5) be eliminated, unless EPA explains what 

additional showing would be needed by that paragraph.

According to commenter 0162, the requirement in proposed §63.456(a)(9) that the source 

“have prepared a written root cause analysis to determine, correct and eliminate the primary

causes of the malfunction and the excess emissions resulting from the malfunction event at 

issue” again does not implement the statutory criteria for standard-setting under section 112. The 

commenter stated that the requirement, if read literally, would mean that a source could never 

take advantage of the affirmative defense if the source was unable to determine the primary

cause of the malfunction or was unable to correct that cause. The commenter noted that EPA has 

defined a malfunction as an event that is “unavoidable” and unforeseeable, and “not reasonably 

preventable” (see proposed §63.456(a)(1)(ii)&(iii) and §63.2) and indicated that, in many cases, 

it is expected that the primary cause(s) of the malfunction will not be ascertainable, or it will not 

be possible to identify a way to ensure the malfunction will not recur.144 In addition, the 

commenter argued that requiring the facility to eliminate the primary causes of the 

malfunction—without regard to “taking into consideration the cost of achieving such” 

 

144 According to commenter 0162, EPA has long acknowledged this reality in the NSPS GP, which requires that 

written reports of excess emissions include the “nature and cause of any malfunction, if known....” See 40 CFR

60.7(b)(2) (emphasis added). The commenter argued that it would be arbitrary and capricious for EPA not to include 

similar language here.
151

elimination and the “non-air quality health and environmental impacts and energy requirements” 

associated with its elimination—is unreasonable and entirely inconsistent with the criteria for 

standards established under CAA section 112(d).145

Commenter 0168 suggested that EPA consider making the following modifications to the 

regulatory language in §63.456 (using strikeout to show text deleted and underline to show text 

added) to address the concerns mentioned above and to make affirmative defense a more useful 

tool:

§ 63.456 Affirmative Defense for Exceedance of Emission Limit During Malfunction. 

In Response to an action to enforce the standards set forth in paragraphs §§ 63.443(c) and 

(d), 63.444(b) and (c), 63.445(b) and (c), 63.446(c), (d), and (e), 63.447(b) or § 63.450(d) 

the owner or operator may assert an affirmative defense to a claim for civil penalties for 

exceedances of such standards that are caused by malfunction, as defined at 40 CFR 63.2. 

Appropriate penalties may be assessed, however, if the owner or operator fails to meet 

the burden of proving all of the requirements in the affirmative defense. The affirmative 

defense shall not be available for claims for injunctive relief.

(a) To establish the affirmative defense in any action to enforce such a limit, the owner or 

operator must timely meet the notification requirements in paragraph (b) of this section, 

and must prove by a preponderance of evidence that: 

(1) The excess emissions: 

(i) Were caused by a sudden, infrequent, and unavoidable not reasonably preventable

failure of air pollution control and monitoring equipment, process equipment, or a 

process to operate in a normal or usual manner, and 

(ii) Could not have been reasonably prevented through careful planning, proper design or 

better operation and maintenance practices; and 

(iii) Did not stem from any activity or event that could have been reasonably foreseen and 

avoided, or planned for; and 

(iv) Were not part of a recurring pattern indicative of inadequate design, operation, or 

maintenance; and 

(2) Repairs were made as expeditiously as possible when the applicable emission 

limitations were being exceeded. Off-shift and overtime labor were used, to the extent 

practicable to make these repairs; and 

(3) The frequency, amount and duration of the excess emissions (including any bypass) 

were minimized to the maximum extent practicable during periods of such emissions; and 

(4) If the excess emissions resulted from a bypass of control equipment or a process, then 

the bypass was unavoidable to prevent loss of life, personal injury, or severe property 

damage; and 

 

145 As an example, commenter 0162 stated that it might be theoretically possible to eliminate the excess emissions 

associated with the malfunction by installing totally redundant pollution control equipment, or pollution control 

equipment with far more capacity than needed for normal operations. However, the commenter argued, this would 

not reflect the performance of the best performers on which the MACT “floor” is to be based, nor would it appear to 

take cost and other factors into consideration as the statute requires for beyond-the-floor MACT standards. The 

commenter further argued that the proposed requirement to eliminate “the primary causes of the malfunction” and 

not just to eliminate “the excess emissions resulting from the malfunction event” lies entirely outside of EPA’s 

authority under the CAA, which the commenter said is limited to establishing and enforcing emission limitations, 

not dictating plant operations.
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(5) All possible Reasonable steps were taken to minimize the impact of the excess 

emissions on ambient air quality, the environment and human health; and 

(6) All eEmissions monitoring and control systems were kept in operation if at all 

possible, consistent with safety and good air pollution control practices; and 

(7) All of the aActions in response to the excess emissions were documented by properly 

signed, contemporaneous operating logs; and 

(8) At all times, tThe affected source was operated in a manner consistent with good 

practices for minimizing emissions; and 

(9) A written root cause analysis report has been prepared, the purpose of which is to 

determine, correct, and eliminate mitigate the primary causes of the malfunction and the 

excess emissions resulting from the malfunction event at issue. Facility personnel will 

determine the appropriate type of analysis required (may include but not limited to root 

cause analysis, failure mode and effect, fault tree, etc.) to identify the cause of the 

malfunction. The analysis report shall also specify, using best monitoring methods and 

engineering judgment, the amount of excess emissions that were the result of the 

malfunction. 

(b) Notification. The owner or operator of the affected source experiencing an 

exceedance of its emission limit(s) during a malfunction shall notify the Administrator by

telephone or facsimile (FAX) transmission as soon as possible, but no later than two 

business days after the initial occurrence of the malfunction, if it wishes to avail itself of 

an affirmative defense to civil penalties for that malfunction. The owner or operator 

seeking to assert an affirmative defense shall also submit a written report to the 

Administrator within 45 days of the initial occurrence of the exceedance of the standard 

in paragraphs §§ 63.443(c) and (d), 63.444(b) and (c), 63.445(b) and (c), 63.446(c), (d), 

and (e), 63.447(b) or § 63.450(d) to demonstrate, with all necessary supporting 

documentation, that it has met the requirements set forth in paragraph (a) of this section. 

The owner or operator may seek an extension of this deadline for up to 30 additional days 

by submitting a written request to the Administrator before the expiration of the 45 day

period. Until a request for an extension has been approved by the Administrator, the 

owner or operator is subject to the requirement to submit such report within 45 days of 

the initial occurrence of the exceedance.

Response: Based on Response from Shipbuilding/Wood Furniture Many of the 

conditions in the affirmative defense are modeled after the affirmative defense in EPA’s State 

Implementation Plan (SIP) SSM policy, see, e.g., State Implementation Plans: Policy Regarding 

Excessive Emissions During Malfunctions, Startup, and Shutdown (Sept. 20, 1999); other 

conditions are modeled after a Federal Implementation Plan (FIP) promulgated by EPA 

(§50.1312). The EPA’s view is that use of consistent terms in establishing affirmative defense 

regulations and policies across various CAA programs will promote consistent implementation 

of those rules and policies.

The EPA believes the affirmative defense criteria are well-defined and will assist EPA 

and the courts in making reasoned determinations as to the establishment of affirmative defenses. 

The EPA and the courts have expertise and experience in evaluating and applying criteria such as 

those for the affirmative defense. As noted above, many of the conditions were modeled after the 

conditions of the affirmative defense in EPA’s SIP SSM policy, which several states have 

adopted into their SIPs. We do not have any indication that parties to enforcement proceedings 
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have had any significant difficulties applying the terms of these SIP affirmative defenses. 

However, EPA believes that some of the terms or phrases in the regulatory text establishing the 

affirmative can be revised or streamlined to some extent.

Based on Response from Oil and Gas The EPA has evaluated some of the affirmative 

defense criteria as follows for promulgation:

 Timely Notification: The EPA has removed the requirement to notify the EPA within 

2 days of violation of a standard in order to be able to avail themselves to a claim for 

affirmative defense. The EPA instead allows owners or operators seeking to assert an 

affirmative defense to demonstrate, with all necessary supporting documentation (as was 

required under the proposed 45-day report), that it has met the affirmative defense criteria 

by submittal of the affirmative defense report in the first periodic compliance, deviation 

report or excess emission report otherwise required after the initial occurrence of the 

violation of the relevant standard (which may be the end of any applicable averaging 

period). If such compliance, deviation report or excess emission report is due less than 

45 days after the initial occurrence of the violation, the affirmative defense report may be 

included in the second compliance, deviation report or excess emission report due after 

the initial occurrence of the violation of the relevant standard. This change provides 

sources with sufficient time to demonstrate that they have met the required affirmative 

defense criteria.

 “Infrequent” Events: The EPA believes that if malfunctions occur on a frequent basis that 

the basis for the malfunction more likely falls in the categories of poor design, poor 

operational decision making, or failure to operate a source in a normal manner and has 

retained the word “infrequent” in this criteria element. 

 “Off-shift and overtime labor”: The EPA believes that, rather than impair a sources 

response to a malfunction, the use of off-shift and overtime labor supports the premise 

that urgency is necessary to minimize to the maximum extent practicable all excess 

emissions associated with a malfunction and has retained this language in the criteria. 

Severe Property Damage: The EPA believes that a bypass of control equipment or a 

process, which results in a violation, should be an exception and not undertaken lightly, 

and has maintained the word “severe” in this criteria.

 Signed Operating Logs: As an alternative, the EPA accepts electronically signed 

operating logs where the format and method of submission meets the regulatory criteria 

and are compatible with the EPA and the delegated authorities’ electronic submission 

systems. Any source submitting records electronically should exercise due diligence to 

assure receipt by the EPA and the delegated authority.

 Root Cause Analysis: The EPA believes it has provided clear criteria within the 

affirmative defense provisions to support the development of an affirmative defense 

report. The EPA believes that these provisions will result in a minor administrative 

burden, but will result in sources analyzing their violation emissions to reduce or avoid 

those emissions in the future, which is an environmental benefit. A root cause analysis is 

not mandatory and is only required if a source seeks to assert an affirmative defense. 

However, such an analysis is beneficial in resolving or preventing violations and excess 

emissions whether the source seeks to assert the affirmative defense or not. A root cause 

analysis is one example of what constitutes good air pollution control practices to 
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minimize emissions. A root cause analysis is not required for every malfunction, as 

specified above, and is only required for those malfunctions for which the source chooses 

to assert an affirmative defense.

101. Comment: Burden. Commenter 0162 said that it was unclear where EPA found the legal 

authority in the CAA to shift the burden to the regulated community of proving (or disproving) 

essential elements of an alleged violation. The commenter stated that the CAA is silent as to the 

issue, and “the ordinary default rule [is] that plaintiffs bear the risk of failing to prove their 

claims.” Shaeffer v. Weast, 546 U.S. 49 (2005), quoting McCormick on Evidence §337, at 412 

(“The burdens of pleading and proof with regard to most facts have and should be assigned to the 

plaintiff who generally seeks to change the present state of affairs and who therefore naturally

should be expected to bear the risk of failure or proof or persuasion”); C. Mueller & L. 

Kirkpatrick, Evidence §3.1, p. 104 (3d ed. 2003) (“Perhaps the broadest and most accepted idea 

is that the person who seeks court action should justify the request, which means that the 

plaintiffs bear the burdens on the elements in their claims”). According to the commenter, while 

the Supreme Court has recognized exceptions such as affirmative defenses, courts retain the 

authority to establish such rules unless Congress acts to delegate that authority.

Finally, commenter 0162 rejected as unreasonable and unnecessary the requirement in 

proposed §63.456(b) to notify the Administrator by telephone or fax as soon as possible, but no 

later than two business days after the malfunction begins, and then to submit a written report 

within 45 days of the initial occurrence of the malfunction that demonstrates, “with all necessary

supporting documentation,” that the source met all of the multitude of criteria for the affirmative 

defense. The commenter stated that it is novel at best for a person to be determined to have acted 

unlawfully unless the person has submitted his entire defense before he is even notified of a 

potential enforcement action. The commenter pointed out that, in many cases, it would be 

obvious to the enforcement authority, based on the kind of short malfunction or deviation report 

sources already submit under many air programs, that an exceedance of the proposed standards 

resulted from an unforeseen and unavoidable equipment failure or process upset. According to 

the commenter, it is extremely inefficient and burdensome, for both sources and regulators, to 

require a complete justification of the affirmative defense before the enforcement authority has 

indicated any need for further investigation.

Other commenters (0164, 0168, 0163 and 0207) also pointed out that, since EPA would 

require a source operator to demonstrate he qualifies for the affirmative defense at the time the 

exceedance occurs, the proposed SSM provisions would impose huge paperwork burdens on 

industry and on the enforcement agencies that are not necessary or justifiable. Commenter 0164 

stated that promulgating a requirement that EPA knows cannot be met with the identified control 

technology, and then forcing a company to prove it is entitled to suspension of civil penalties for 

such events, raises serious constitutional questions. Commenter 0164 noted that even if it were 

legally acceptable (which it is not) for EPA to promulgate unworkable emission standards and 

then offer an affirmative defense to penalties for the expected exceedances of those standards, 

the restrictions and requirements EPA proposes for the affirmative defense are unreasonable and 

impracticable. If EPA persists in relying on a defense contained in the standards in lieu of 

promulgating proper standards that apply during malfunction periods, the affirmative defense in 

the proposed rule would at a minimum require substantial modification and streamlining.
155

According to commenter 0162, since the affirmative defense is only available if all 

criteria are met, including the 48-hour and 45-day notifications, and since sources will have no 

way of knowing whether there might be an enforcement action or citizen suit at some point in the 

future addressing the period affected by a malfunction, sources will need to submit notifications 

of the malfunction, with all the supporting documentation, whenever a malfunction defense 

could be claimed. The commenter asserted that this will swamp EPA and state agencies with 

unnecessary paperwork, and for no clear benefit. The commenter further noted that, if EPA 

ultimately were to conduct a rulemaking to eliminate the excess emission provisions, despite the 

commenter’s arguments for retaining them, there would be even more oral and written reports 

under the proposed affirmative defense. The commenter noted that the events covered by the 

excess emissions may occur often and, while they may last only a few minutes, a mill would 

have no way of knowing whether those incidents might later be part of an enforcement action, so 

the mill may feel compelled to report each of them under the affirmative defense notification 

Response: Based on Response from Secondary Pb The EPA’s view is that an affirmative 

defense to civil penalties for exceedances of applicable emission standards during periods of 

malfunction appropriately balances competing concerns. On the one hand, citizen enforcers are 

concerned about additional complications in their enforcement actions. On the other hand, 

industrial sources are concerned about being penalized for violations caused by malfunctions that 

could not have been prevented and were otherwise appropriate handled (as reflected in the 

affirmative defense criteria). The EPA has used its section 301(a)(1) authority to issue 

regulations necessary to carry out the Act in a manner that appropriately balances these 

competing concerns.

As discussed previously, the EPA has revised the immediate notification and 45-day

malfunction report. The EPA has removed the requirements to notify the EPA within 2 days of 

violation of a standard and has allowed owners or operators to submit the affirmative defense 

report in the next periodic compliance, deviation report, or excess emission report. This should 

reduce the burden on the agencies and industry.

102. Comment: Injunctive Relief. Commenter 0168 noted that EPA does not allow facilities 

to assert an affirmative defense for the exceedance of an emission limit during malfunctions if 

EPA is seeking to enforce that emission limit through injunctive relief. The commenter said that 

the Agency apparently takes that position based on a memorandum, State Implementation Plans: 

Policy Regarding Excessive Emissions During Malfunctions, Startup, and Shutdown at 2 (Sept. 

20, 1999). (SIP SSM Memo) The commenter asserted that this policy is wrong. The type of legal 

action or relief should have no bearing on the availability of this defense. A malfunction is not 

affected by the type of enforcement action that EPA may eventually bring. Indeed, because a 

malfunction is not reasonably preventable, enforcement actions, regardless of type, have no 

deterrent effect on them. Therefore, the type of legal action EPA uses to enforce a violation of its 

emission limits is simply irrelevant to whether the violation should be excused because of 

circumstances beyond the facilities’ control.

Consequently, commenter 0168 asserted that not allowing an affirmative defense in an 

action for injunctive relief is arbitrary and capricious. As the D.C. Circuit Court stated in Essex 

Chem. Corp. v. Ruckelshaus, 486 F.2d 427. 433 (D.C. Cir. 1973) a case reviewing a section 111 

rule, the D.C. Circuit Court held that SSM provisions are “necessary to preserve the 
156

reasonableness of the standards as a whole.” The D.C. Circuit Court of Appeals has also noted 

that “[a] technology-based standard discards its fundamental premise when it ignores the limits 

inherent in the technology.” NRDC v. EPA, 859 F.2d 156, 208 (D.C. Cir. 1988). Therefore, EPA 

should not apply a policy drafted to “ensure that SIPs provide for attainment and maintenance of 

the national ambient air quality standards (“NAAQS”) and protection of prevention of significant 

deterioration (PSD) increments” and other risk-based programs, SIP SSM Memo at 2, to the 

CAA section 129 technology-based program.

Response: Based on Response from Secondary Pb. The EPA has addressed the issue of 

affirmative defense and injunctive relief here and in other recent rulemaking decisions. In

exercising its authority under section 112 to establish emission standards (at a level that meets 

the stringency requirements of section 112), EPA necessarily defines conduct that constitutes a 

violation. The EPA’s view is that the affirmative defense is part of the emission standard and 

defines two categories of violation. If there is a violation of the emission standard and the source 

demonstrates that all the elements of the affirmative defense are met, only injunctive relief is 

available. All other violations of the emission standard are subject to injunctive relief and 

penalties.

Based on Response from Shipbuilding/Wood Furniture Many of the conditions in the 

affirmative defense are modeled after the affirmative defense in EPA‘s SIP SSM policy, See, 

e.g., State Implementation Plans: Policy Regarding Excessive Emissions During Malfunctions, 

Startup, and Shutdown (Sept. 20, 1999); other conditions are modeled after a FIP promulgated 

by EPA. (§50.1312) The EPA‘s view is that use of consistent terms in establishing affirmative 

defense regulations and policies across various CAA programs will promote consistent 

implementation of those rules and policies. Although, as the commenter notes, the SIP policy

does not apply to technology-based standards because the expectation was that technology-based 

standards would contain provisions that already account for technological limitations, nothing in 

the policy addresses the form that such provisions in technology-based standards should take. As 

explained above, EPA has determined that including affirmative defense provisions in such 

standards is appropriate and reasonable. The commenter does not explain their view that the 

terms of the SIP policy are not appropriate to address malfunctions in the CAA section 112 

context. The affirmative defense does not require a facility to prove its innocence rather than 

requiring an enforcement authority to prove a violation of the CAA or change the burden of 

proof with respect to establishing a violation. The affirmative defense applies only where a 

violation has been established. The burden of proof that a violation occurred remains with the 

plaintiff in an enforcement action. See, e.g., §22.24. If a violation has been established and a 

source wishes to assert the affirmative defense with respect to penalties, the source does bear the 

burden of establishing that the elements of the affirmative defense have been met. This burdenshifting is appropriate because the source is in a better position to determine the facts required to 

establish the defense. See, e.g., Arizona Pub. Serv. Co. v. EPA, 562 F.3d 1116, 1120, 1129-30 

(10th Cir. 2009) (rejecting industry challenge to EPA‘s use of an affirmative defense to address 

excess emissions during malfunction events.). The notification and reporting requirements are 

not unreasonable and are consistent with other malfunction reporting and notification 

requirements that have been applied without significant difficulty. (See, e.g., §§63.6(e)(3)(iv) 

and 63.10(d)(5)(ii).) Section 114 of the CAA clearly provides authority to require such reports.
157

8. Excess Emissions Allowances

103. Comment: Excess Emissions Provisions Must Be Removed. Commenter 0218

recommended that the EPA remove the “excess emissions provisions” for all parts of the pulp 

and paper source category, stating that exempting sources from compliance with emission 

standards at any time violates CAA section 112 and section 302, which makes clear that 

emission standards under section 112 must require continuous compliance. The commenter 

argued that the excess emissions allowance provisions are just as unlawful as the SSM 

exemption that the D.C. Circuit Court found to be unlawful, and for the same reasons. The 

commenter stated that: 

 The provisions should require continuous control; 

 The EPA should not consider any of the alternatives that still allow an exemption; and

 The EPA may not set an “alternative numerical emission limit” that would apply during 

times when “no control device is available” due to equipment or process “downtime,” or 

some other problem in the system that is a malfunction.

The commenter noted that, as EPA’s proposal makes clear that there is no evidence that 

the malfunctions, downtime, losses, damage, and other problems described could possibly

qualify for a work practice standard under section 112(h)(4), the EPA must set a numerical 

emission standard “whenever it is feasible” to do so.

The commenter concluded that it may be necessary for sources to apply backup or 

secondary control devices, or detection or repair alerts, in order to prevent uncontrolled 

emissions. The commenter stated that the EPA had no lawful or rational basis for failing to 

remove all exemptions for “excess emissions” for this source category.

Response: We acknowledge the commenter’s concern regarding excess emission 

allowances. We have received more information from the industry regarding these allowances 

and will take action on them at a later date.

104. Comment: Future Correspondence/Discussion. Commenter 0162 stated that, in addition 

to conducting the 8-year review of developments in control technologies under CAA section 

112(d)(6) and the residual risk review under CAA section 112(f) for the pulp and paper category, 

EPA has indicated recently that it is considering eliminating or modifying the excess emission 

provisions in §§63.443(e) and 63.446(g) (See 76 FR 81346). The commenter contended that it 

would be improper and unlawful to do so. Moreover, EPA would need to publish a proposed rule 

for public comment before it could change the excess emission provisions.

The commenter appreciated EPA granting an extension until June 27, 2012 for 

commenters to provide information related to excess emission provisions.146 The commenter said 

this time would be critical for NCASI to undertake the survey described in their letter to Robin 

Dunkins of EPA.

147 Although the commenter could have deferred providing any information on 

 

146 See February 22, 2012 letter from EPA Assistant Administrator Gina McCarthy to AF&PA Vice President Paul 

Noe.

147 See e-mail dated February 15, 2012 from Vipin Varma of NCASI to Robin Dunkins of EPA’s Sector Policies and 

Programs Division.
158

this issue, the commenter shared their legal views and general observations about the need and 

use for the excess emissions provisions. The commenter stated they will provide additional 

comments on the subject before June 27, 2012.

The commenter stated that the pulp and paper industry was not aware of the potential for 

evaluation of the excess emissions allowances until approximately 1 month before the proposed 

rule was published. As such, there has been little coordination between the Agency and the 

commenter to discuss the justification for these provisions or the implications of changing them. 

Therefore, in addition to filing subsequent comments, the commenter would like to work with 

the Agency and set up meetings to discuss these issues, as they are complex, and an efficiency

will be gained through coordination to assist the Agency in comprehension of these systems and 

their limitations and to develop realistic conclusions.

Response: We acknowledge the commenter’s concern regarding the removal of the 

excess emission allowances. We are deferring action on the allowances until a later date and will 

follow the proper regulatory procedures of proposing the changes, providing a public comment 

period, and promulgating a final rule.

We acknowledge and appreciate the commenter’s efforts for providing more information 

regarding the allowances. We have been coordinating efforts to discuss the allowances with 

industry, and the knowledge gained during the discussions, as well as the data we received on 

June 27th, have greatly assisted us in evaluating the removal of the excess emission allowances. 

105. Comment: Current Excess Emission Provisions Represent MACT and Were Included in 

the MACT Floor. Commenter 0162 stated that the excess emission provisions in the current 

subpart S rule reflect EPA’s careful determination, after years of study of a large quantity of 

emissions information and public comments, that the MACT “floor,” representing the emissions 

of the “best performers,” includes emissions during unavoidable periods of releases of 

uncontrolled or partially-controlled pulping process vent gases and unavoidable sewering of 

untreated or partially-treated pulping process condensates (See 63 FR 18504, 18529 (April 15, 

1998)). The commenter cited the 1998 FR notice, as follows:

EPA established appropriate excess emission provisions to approximate the level of 

backup control that exists at the best-performing mills and the associated period of time 

during which no control device is available.” Id. After “an analysis of the public 

comments and the available data regarding excess emissions and the level of backup 

control in the industry,” EPA determined that the “best-performing mills achieve a one

percent downtime in their LVHC system control devices” and “best-performing mills 

achieve a four percent downtime in the control devices used to reduce emissions from 

their HVLC system to account for flow balancing problems and unpredictable pressure 

changes inherent in HVLC control systems.” Id. “The allowances address normal 

operating variations in the LVHC and HVLC system control devices for which the 

equipment is designed. The variations would not be considered startup, shutdown, or 

malfunction under the Part 63 General Provisions....” (See 63 FR 18530). The 10 percent 

excess emission provisions for steam strippers systems “accounts for stripper tray

damage or plugging, efficiency losses in the stripper due to contamination of condensate 
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with fiber or black liquor, steam supply downtime, and combustion control device 

downtime.” Id.

The commenter noted that EPA adopted the excess emission provisions after reviewing 

extensive data from continuous monitoring systems and considering industry comments. Industry

told EPA that, while some mills have backup combustion devices as part of their LVHC control 

system, venting of pulping gases is an essential safety practice (because of their explosion 

hazard). It is essential even for those systems with backup control devices, since the startup of, 

and transfer of vent gases to, the backup controls cannot be immediate or automatic for safety 

reasons, and operating variability in the control devices themselves is unavoidable for process 

and other reasons.148 The commenter noted that, for HVLC systems, few mills had backup 

controls that could handle the large volume of vent gases, so any standard that required the use of 

backup devices would have been beyond the MACT “floor” and would not have been costeffective due to the low concentration of pollutants in the large gas stream.149

In short, the commenter contended that the MACT determinations EPA made when 

promulgating the original subpart S emission standards correctly concluded that available 

technology involves unavoidable periods where not all vent gases or condensates can be routed 

to the control device, and/or when the control device is inoperable or necessarily operating at a 

reduced rate. The subpart S emission standards (including the excess emission provisions) were 

designed to reflect the performance of the MACT technology and the actual performance of the 

“best performing” mills. Without the excess emission provisions, the remainder of the subpart S 

emissions standards would impose limitations not achieved even by the “best performers” and 

not demonstrated as achievable at any facility. The commenter argued that this plainly is not 

what Congress intended.150

Response: We acknowledge the commenter’s discussion of the development and use of 

the excess emission allowances. We also agree that the excess emission provisions were 

developed using extensive data during the promulgation of the original rule. We are deferring

action regarding the excess emission allowances in order to analyze more recent information that 

we have obtained from industry.

106. Comment: No Technical Justification for Eliminating Excess Emission Provisions. 

Commenter 0162 noted that EPA is supposedly carrying out Congress’ directive in CAA section 

112(d)(6) that, at least every 8 years, EPA review whether “developments in practices, processes, 

and control technologies” necessitate revision of MACT emissions standards. The commenter 

 

148 See, e.g., Pulp, Paper and Paperboard Industry – Background Information for Promulgated Air Emission 

Standards – Final EIS, EPA-453/R-93-050b (October 1997) (“BID”) at 4-81, 4-82 to 4-84; AF&PA April 18, 1994 

comments on the proposed MACT standards for Pulp and Paper Mills, p. MACT-61 (events resulting in venting of 

NCGs are “integral to process variability,” and combustion devices will “predictably” not perform at their design 

efficiency ”some small percentage of the time, even when they are being operated properly and all equipment is in 

order”); id. p. MACT-173-74.

149 See 63 FR 18529; BID at 4-81 to 4-82; AF&PA April 18, 1994 comments at MACT-61 (degree of venting 

allowance needed is “independent of the availability of backup combustion devices because of the safety and 

engineering concerns”); id. at MACT-174 (backup combustion devices for HVLC systems could be an additional 

cost of $1 billion.

150 See, e.g., Sierra Club v. EPA, 353 F.3d 976, 980 (D.C. Cir. 2004); Sierra Club v. EPA, 167 F.3d 658, 665 (D.C. 

Cir. 1999).
160

stated that nothing has changed about the technology available to control volatile HAP emissions 

at pulp mills that eliminates the unavoidable excess emissions during the events that EPA 

accurately described when promulgating the current MACT standards. Absent such new 

technology, the commenter believes there is no statutory predicate for EPA to go back and 

change the MACT standards at this time.151

The commenter argued that even if the section 112(d)(6) technology review were an 

opportunity to second guess and revise the existing MACT standards, EPA has no technical basis 

for eliminating the subpart S excess emission provisions. The commenter stated that an agency

cannot simply change its mind and reach a diametrically-opposed conclusion from the 

determination made in a prior rulemaking. Rather, EPA must demonstrate sufficient basis for 

changing its prior conclusions; in this case, technical justification for concluding that mills with 

MACT controls do not experience the unavoidable variability described by EPA in promulgating 

the subpart S rule and accommodated by the excess emission provisions.152

The commenter stated that there is no health or environmental imperative for eliminating 

the excess emission provisions in subpart S. The commenter noted that EPA has just completed 

its “residual risk” review and concluded that there is no significant risk from emissions 

(including excess emissions) allowed under subpart S. The commenter noted that the emissions 

data that EPA used in its risk modeling included emissions during bypassing of control 

equipment or other excess emissions covered by the subpart S excess emission provisions.

Similarly, commenter 0172 contended that it would be improper and unlawful for EPA to 

limit or eliminate the excess emissions allowances for LVHC, HVLC, and strippers. The 

commenter argued that EPA does not have the authority to modify or eliminate the excess 

emissions allowance provisions for pulp mill venting or steam strippers included in subpart S. 

These existing provisions were part of the MACT floor for this subcategory and cannot be 

modified without demonstrating that there have been “developments in practices, processes and 

control technologies” or that there is a change necessary to protect human health in a “residual 

risk” review. The commenter asserted that EPA has not made either demonstration.

Response: We acknowledge the commenters’ concerns regarding the removal of the 

excess emission allowances. We have received more information regarding these allowances and 

will take action on them at a later date.

107. Comment: Intervening Court Decisions Do Not Justify Eliminating Excess Emission 

Provisions. Commenter 0162 argued that intervening court decisions do not justify eliminating 

the excess emission provisions. The subpart S NESHAP was never judicially challenged, and the 

time for such a challenge under CAA section 307(b) has long passed. Even if there were some 

portion of an opinion in one of the many cases challenging other NESHAPs that was contrary to 

the approach EPA took in promulgating subpart S, that would not provide a means nor a 

 

151 Cf. NRDC v. EPA, 529 F.3d 1077, 1084 (D.C. Cir. 2008) (rejecting contention that CAA section 112(d)(6) 

requires EPA to “start from scratch” and develop new MACT standards).

152 See, e.g., FCC v. Fox Television Stations, Inc., 556 U.S. 502, 129 S. Ct. 1800, 1811 (2009) (“a reasoned 

explanation is needed for disregarding facts and circumstances that underlay...the prior policy”); Transactive Corp. 

v. United States, 91 F.3d 232, 237 (D.C. Cir. 1996).
161

justification for reopening subpart S standards that were never challenged on that grounds.153

Regardless, the commenter contended that none of the holdings in other cases undercuts 

inclusion of the excess emission provisions in subpart S.

The commenter acknowledged that EPA may believe that elimination of the excess 

emission provisions is justified or required by the D.C. Circuit Court’s decision in Sierra Club v. 

EPA, 551 F.3d 1019 (D.C. Cir. 2008), cert. denied, 130 S. Ct. 1735 (2010), which vacated the 

“exemption” for excess emissions during SSM events contained in the 40 CFR part 63, subpart A 

GP. The commenter noted EPA’s suggestion that the excess emission provisions are “arguably at 

odds with” that decision (See 76 FR 81346). To the contrary, the commenter believes the D.C. 

Circuit Court’s Sierra Club decision is not inconsistent with, and would not justify EPA’s 

retroactive elimination of, the subpart S excess emission provisions. The commenter provided 

three reasons in support of their position:

 First, the Sierra Club decision interpreted the NESHAPs GP, not the subpart S NESHAP 

or indeed any categorical NESHAPs. 

 Second, the decision addressed an exemption for startups, shutdowns, and malfunctions, 

while the subpart S excess emission provisions for pulping vent gases specifically does 

not address excess emissions during SSM (see §63.443(e)), and the provision for pulping 

condensates only covers such events because EPA did not have data to distinguish those 

situations from “normal stripper operating emissions” (see 72 FR 18529-30).

 Third, the Sierra Club decision rejected the GP’s blanket, open-ended exemption for 

emissions during SSM periods, finding it to be inconsistent with Congress’s intention that 

“there must be continuous section 112-compliant standards” for sources subject to 

MACT standards, rather than periods where no standard of any kind applies. See 551 

F.3d at 1027. The problem with the GP SSM exemption, in the D.C. Circuit Court’s eyes, 

was that it allowed sources to be exempt from any standard at all, and that it was not 

derived (by EPA’s admission) applying the factors in CAA section 112(d) or 112(h). See 

id. at 1027-28, 1030. The Sierra Club opinion did not address a situation, such as the 

subpart S standards, where EPA finds that the MACT standard, which applies 

continuously, must account for periods of higher emissions during unavoidable 

operational variability to accurately reflect the available technology and the best 

performers’ emissions.154

 

153 See id. and, e.g., Sierra Club v. EPA, 353 F. 3d at 986 (MACT standards judged on the adequacy of EPA’s 

explanation in the particular rulemaking, not on what EPA did based on a different record in a different rulemaking).

154 See BID at p. 1-41 (“EPA established excess emission allowances to approximate the level of downtime and 

number of backup control devices that exist at the best-performing mills. The Excess emissions allowances are 

designed to account for periods when the control device is inoperable and when the operating parameter values 

established during the initial performance test cannot be maintained due to problems with the process.”). Thus, the 

commenter contended that EPA’s statement, in the preamble to the proposed rule, that the excess emission 

provisions of the current regulations “create time periods during which a source does not have to comply with a 

CAA section 112-compliant standard” (see 76 FR 81 346) is simply contrary to the record for the existing Subpart S 

rulemaking.
162

Response: We acknowledge the commenter’s concern regarding the removal of the 

excess emission allowances. We have received more information regarding these allowances and 

will take action on them at a later date.

108. Comment: Provisions Are Consistent with CAA. According to commenter 0162, EPA 

lacks authority to go back and re-assess the existing MACT standards for reasons unrelated to 

CAA sections 112(d)(6) and 112(f). But even if EPA did have authority, the commenter argued

that the excess emission provisions in the existing subpart S regulations are entirely consistent 

with the CAA and with past EPA practice. The commenter stated that the excess emissions 

provisions represent the performance of the best-performing mills. The commenter stated that 

without the excess emission provisions, the subpart S standards would violate CAA section 112 

because section 112(d) standards are supposed to represent "the emissions control that is 

achieved in practice" by the best performers, which means that the best-perfoming mills would 

not violate the standards, which “only results if ‘achieved in practice’ is interpreted to mean 

‘achieved under the worst foreseeable circumstances.’” Sierra Club v. EPA, 167 F.3d 658, 665 

(D.C. Cir. 1999). The courts (and EPA) have recognized that there is variability in the 

performance of control technologies, which needs to be accounted for in establishing emission 

limitations based on the MACT floor. See, e.g., Cement Kiln Recycling Coalition v. EPA, 255 

F.3d 855, 862-865 (D.C.Cir.2001). As the record reflects, it is certainly foreseeable that even the 

best performers would experience violations of the MACT standards, due to process variability

and control technology limitations, without an excess emission allowance.

According to the commenter, EPA has implied that the excess emission provisions in the 

existing subpart S regulations somehow are inconsistent with the D.C. Circuit Court’s vacatur of 

the NESHAP GP SSM exemption because they do not provide a numerical limitation on 

emissions during certain periods (See 76 FR 81346). However, according to the commenter, 

nothing in Sierra Club v. EPA said that MACT standards have to be the same at all times; to the 

contrary, the Court recognized that they might not be. See 551 F.3d at 1021, 1027.

The commenter stated that the excess emission allowances are no different in principle 

from the averaging periods that EPA applies almost universally in setting the MACT standards: a 

source complies with the average emission limitation even though there are times during the 

averaging period when the source’s emissions are much higher than the rate specified in the 

standard. Also, EPA has included excess emission provisions analogous to those in subpart S in 

NSPS issued under CAA section 111, even though the same definition of “emission limitation” 

and “emission standard” (relating to limiting emissions of air pollutants on a continuous basis) 

applies to NSPS. For example, in the NSPS for Kraft pulp mills, EPA recognized the complex 

factors affecting recovery furnace operations and provided an excess emission allowance 

(§60.284(e)), in addition to the SSM provision in §60.8(c).

The commenter stated that, in effect, elimination of the excess emission provisions would 

put pulp and paper mills in a “Catch-22” situation: the MACT standards would no longer 

accommodate the excess emissions that EPA knows will occur regularly during normal mill 

operations, as a result of process variability and control equipment operations and availability. 

Yet those same events would appear to be ineligible for the “affirmative defense” that EPA 

proposes as a means of addressing excess emissions that occur despite a source’s proper design 

and operation, since the “affirmative defense” is only available for excess emissions that result 
163

from unforseeable and infrequent events (see proposed §63.456(a)). This would be unreasonable, 

arbitrary and capricious, and not in any way required by the CAA or judicial precedent.

Response: We acknowledge the commenter’s concern regarding the removal of the 

excess emission allowances. We have received more information regarding these allowances and 

will take action on them at a later date.

109. Comment: Excess Emission Provisions Necessary Due to Inherent Process Variability, 

Design, and Technology Reasons. Commenter 0162 stated that the excess emissions provisions 

are necessary to accommodate inherent process variability, design, and technology features.

Provisions for a small amount of LVHC and HVLC system venting and stripper downtime were 

developed as part of the MACT “floor,” based on the fact that even the best-performing units 

could not meet the standards at all times. As the technology for the collection and treatment of 

HAPs under subpart S has not changed, neither has the capability for mills to operate without 

needing these provisions. These provisions are necessary due to process variability and not for 

situations defined as SSM. These events generally are not due to situations where some 

equipment has broken down and must be repaired to correct the situation, but are due to process 

variability and safety interlocks which have caused a situation that requires a release.

Commenter 0172 explained that vent gas collection systems are built to collect emissions 

from process equipment and to route these emissions to a single control device for destruction. 

Examples under subpart S include collection of vent gases from digester systems (which are 

commonly composed of multiple batch digesters), evaporator trains (some mills have more than 

one), condensate collection tanks, turpentine recovery systems, stripper feed tanks, and heat 

recovery systems. The collected gases from these systems are routed to an incineration device 

(typically a stand-alone incinerator, lime kiln or boiler) for destruction. This incinerator may be 

located a considerable distance from the process equipment and, thus, very long piping runs are 

involved. In order to protect the system, safety release vents are built into the piping system to 

protect it from over- (or under-) pressure spikes from the process equipment. These devices are 

referred to as pressure/vacuum (PV) valves and rupture disks. 

According to commenter 0172, even at the best performing mills, at all times during 

periods of SSM, the process equipment may be subject to over-pressure or high-temperature 

spikes. Furthermore, given the complexity of these systems and the sources they control, there 

may be normal operating periods where process variability creates a momentary pressure or 

temperature fluctuation. These pressure/temperature spikes need to be relieved by releasing to 

the atmosphere immediately through the PV valves close to the process equipment to prevent 

damage to the piping system. Opening a vent valve at the control device (which may be located a 

long distance from the process equipment) does not provide sufficient protection for the piping 

system. The EPA must retain the excess venting allowance for these situations to avoid unfairly

penalizing facilities for safety-related venting to protect key process equipment. 

Commenter 0172 stated that EPA must recognize that the venting allowance applies to 

the vent collection system as well as the final control device. The EPA has stated that the venting 

allowance applies only from the system as a whole and not from individual sources and that the 

control device must be inoperative for the gas stream to legitimately bypass the control 
164

system.155 However, as described above, to protect vital equipment, there are normal operational 

situations requiring venting of gases immediately in the closed-vent collection system near the 

process equipment, which may be located far from the control device. Even if it were possible to 

vent at the control device in such instances, EPA’s interpretation that the venting allowance is 

applicable only if the control device is inoperative is not appropriate given the complex nature of 

the closed-vent collection system. The most obvious solution, and the one that minimizes 

emissions to the maximum extent possible, would be to recognize the safety and technical need 

for localized pressure relief by allowing venting (subject to the 1 percent/4 percent allowance) 

anywhere within the closed-vent collection system where safety-related venting is required,

while maintaining normal operation of the final control device to control emissions from all the 

other process equipment in the system.

Commenter 0172 stated that venting from LVHC and HVLC systems can occur as a 

result of normal process variability not associated with startups, shutdowns, or malfunctions in 

pulp mill process equipment, closed-vent collection systems, or vent gas control equipment. The 

1 percent/4 percent venting allowance is necessary to protect mills from enforcement exposure 

during these normal events. One example of this variability is a sudden change in the steam 

system pressure, which can be caused by sudden shutdown of process equipment outside the 

pulp mill (such as a paper machine) or an operational problem with one of the boilers themselves 

(such as interruption of fuel flow to a power boiler or loss of black liquor to a recovery furnace). 

This sudden spike or reduction of steam pressure could cause two problems resulting in venting 

from the closed vent control system or at the final control device: 

 Steam eductors in the vent gas control system would not maintain sufficient vacuum in 

the closed vent control system, causing an overpressure situation which would cause the 

PV valves to open. 

 This sudden change in steam header pressure could cause operational problems in pulp 

mill equipment such as an evaporator system. The sudden pressure change could cause 

the evaporator to “carry over” black liquor from one of the effects into the vapor space of 

the unit, creating an unstable operating condition, with the likelihood of LVHC gas 

venting due to overpressure. 

Commenter 0172 contended that it is impractical and/or unreasonably expensive to 

completely eliminate LVHC and HVLC venting due to the safety considerations and process 

variability. Therefore, at a minimum, EPA must retain the 1 percent/4 percent venting allowance 

to cover these situations. Without the venting allowances, mills would need to eliminate all 

venting not related to safety or normal variability. For a mill to completely eliminate all the other 

vents would require extraordinarily costly process modifications. Following are some examples 

of these process modifications:

 Full engineering analysis of the process equipment, vent gas collection system and final 

control devices. It is anticipated that significant capital would be required to make these 

systems completely vent-free (such as “bumpless transfer” between control devices). 

 Even though mills presently have backup systems for LVHC incineration, many are not 

kept in a “hot” condition and, thus, are subject to a waiting period before being available 

for burning of LVHC gasses. To keep backup control devices in a “hot” mode would 

 

155 See EPA Region 9 Applicability Determination M990012 (September 30, 1999).
165

involve extra operating costs. Some existing backup control devices are not 100 percent

reliable and mills would have to install a third backup. 

 As noted above, HVLC systems at many mills do not have backup incineration sources. 

Without the venting allowance, these facilities would need to install a backup control 

device and, to be 100 percent reliable, perhaps even a third backup.

Response: We appreciate the information provided by the commenter regarding the 

excess emission allowances. We will use this information, as well as information we received

from industry to further investigate these allowances. We will take action on the excess 

emissions allowances at a later date.

110. Comment: Commenter 0228 requested that EPA maintain the 1 percent and 4 percent

vent allowances. These limits reflect the reality that, given the complexity of the NCG collection 

systems, vents are inevitable. Collection systems in pulp and paper mills are effective at 

capturing gases generated at various points within the process, preventing those gases from 

becoming explosion hazards, and delivering gases to combustion units. Unplanned events such 

as combustion unit shutdowns, pressure changes within the system, flame arrester pluggages, or 

valve malfunctions occur at even the best-controlled mills. Due to the unpleasant odor of NCG 

gases and the impacts of that odor within the mill and local communities, facilities do not 

generally vent unless there is some kind of operational or safety-related event that makes venting 

necessary to prevent damage to equipment and/or maintain a safe working environment.

The commenter has regulated the release of NCGs since the early 1990s (see Maine 

Department of Environmental Protection Rule 06-096 CMR 124, “Total Reduced Sulfur Control 

from Kraft Pulp Mills”). An important part of that regulation limits individual LVHC gas release 

events to 40 minutes. The restricted duration of individual LVHC gas events discourages mills 

from venting for long periods of time and reduces the likelihood that mills will ultimately exceed 

the 1 percent quarterly limit on LVHC gas vents required under subpart S. The combination of 

the 40 minute individual event limit and 1 percent quarterly limit has proven to be an effective 

and practical method of limiting LVHC emissions. The commenter suggested that EPA consider 

such a duration limit for individual LVHC events. As opposed to considering every vent a 

potential violation, the 40-minute limit combined with the 1 percent quarterly aggregate limit 

would reduce the number of affirmative defense cases submitted by affected facilities.

Response: We appreciate the information provided by the commenter regarding the 

excess emission allowances. We will use this information, as well as information we received

from industry to further investigate these allowances. We will take action on the excess

emissions allowances at a later date.

111. Comment: Information Requested by EPA on Releases

Emissions Estimates. Commenter 0162 noted that EPA requested information on the 

estimated emissions that occur during periods covered by the excess emission provisions. The 

commenter stated that it is not possible to quantify emissions on a site- or event- specific basis. 

The commenter is not aware of any successful measurements of releases from vents during a 

release. The commenter explained that emissions will vary based on the cause, location, and 

source of the release. Emissions will vary not only between mills and sources but between the
166

same sources at the same mill under different circumstances. The commenter noted that NCASI 

has developed limited data sets for main vents (vents immediately prior to the control device that 

include gases from all collected sources) under normal operations. However, site-specific data 

cannot be collected for the releases listed above, as the events cannot be anticipated, the events 

are typically short in duration, and it is unsafe to perform sampling. The commenter stated that 

the reasons EPA gave for not setting emission limits in the original standards have not changed:

At proposal EPA did not have sufficient data to establish a mass emission limit or a mass 

emission reduction percentage across each mill. Since proposal [in 1993], EPA obtained 

site-specific information that was used to develop emission factors for various systems at 

a mill. However, these emission factors represent average or typical systems and are not 

specific to each mill. While EPA believes such information may be used to estimate 

national impacts, it is not adequate to determine the MACT floor level of control (i.e., the 

factors are not representative of the actual emissions at each mill but may be used to 

represent typical emissions from all mills). Actual mass emission levels or mass emission 

reductions would still be required. Information on the controls for various systems at each 

mill was available to EPA. Therefore, EPA decided to develop MACT floors on a unit 

(i.e., system) basis.156

The commenter noted that estimating total source category emissions associated with the 

excess emission provisions is very difficult, for the same reasons. The commenter stated that,

during the extended comment period that EPA has allowed for comment on the excess emission 

provisions of the subpart S standards, AF&PA, NCASI, and industry representatives will be 

exploring ways in which the industry might respond to EPA’s request for emission estimates.

Work Practices Currently Employed. Commenter 0162 stated that mills were required to 

develop SSM plans under subpart S, and that mills use these plans and standard operating 

procedures to define the work practices mills must follow to minimize emissions during a 

release.

Procedures To Monitor Releases. Commenter 0162 stated that, depending on the process 

and system design, mills monitor the location and time of releases by pressure (most popular), 

valve position, temperature at the vent location or flow meters. Facilities record this information 

either electronically or in log books and report events as currently required under subpart S.

Ventless Transfer Systems. Commenter 0162 stated that some systems can be designed 

for ventless transfer between the primary and back-up control device; however, these systems 

cannot prevent venting 100 percent of the time. The commenter noted that these systems would 

only experience ventless transfer if all the conditions are met such that the interlocks do not 

prevent introduction of the gases to the alternate treatment device. However, some units cannot 

be designed for ventless transfer. Examples include:

 Systems with recovery furnaces, to assure that the burner is not plugged. Light-off of the 

igniter must be initiated at the burner front, and then only after inspecting the burner 

opening in the furnace wall to ensure that there is no plugging.

 

156 See EPA-453/R-93/050b, October 1997, page 4-6.
167

 Systems that have different types of boilers as the Primary and Back-up Control Devices 

(i.e., one boiler is under positive pressure, and the other boiler is under negative 

pressure).

 Systems such as oxidizers that were installed as Back-up Control Only (these units are 

typically not maintained in a “hot” state to immediately accept gases to minimize fuel 

burning and emissions, and for energy conservation).

Response: We appreciate the information provided by the commenter regarding the 

excess emission allowances, SSM plans, procedures to monitor releases, and ventless transfers. 

We will use this information, as well as information we received from industry to further 

investigate these allowances. We will take action on the excess emissions allowances at a later 

date.

112. Comment: Responses to EPA’s Questions on Provision Options

Work Practice Justification. As noted above, the commenter contended that the excess 

emission provisions should be maintained in the rule because the provisions are necessary for 

technological reasons, due to system design for safety and process operating variability–not due 

to a desire to avoid penalty for excess emissions during periods of SSM. The commenter asserted 

that EPA must propose a new rule and allow for comment prior to revision of the standard. 

Although the commenter disagreed that a change to the provision is required, the commenter 

asserted that the only acceptable alternative is a work practice. The commenter pointed out that 

the CAA states “if it is not feasible in the judgment of the Administrator to prescribe or enforce 

an emission standard for control of a hazardous air pollutant or pollutants, the Administrator 

may, in lieu thereof, promulgate a design, equipment, work practice, or operational standard, or 

combination thereof.”157 In order for an emission standard to be infeasible, the Administrator 

must determine that “the application of measurement methodology to a particular class of 

sources is not practicable due to technological and economic limitations.158

Technological Limitations. Commenter 0162 stated that development of a numerical 

emissions standard (other than tracking vent time) is not feasible due to technology limitations. 

The commenter stated that there are no data available to quantify site-specific emissions from the 

vents of LVHC and HVLC systems. In addition, the emissions impact of stripper downtime is 

not clearly understood, as condensates would generally be sewered to the wastewater treatment 

system. The commenter noted that there may be unknown losses to the air from any sewers that 

are open to the atmosphere prior to introduction to the biological treatment system.

The commenter stated that, even if time were allowed to collect additional data, it is not 

possible to measure the emissions from excess emissions events, because the exact time and 

location of the event cannot be anticipated and the events are generally short in duration. In 

addition, collection of these gases is not always possible, as the locations are not always 

accessible and sampling of NCG gases outside the collection system would be dangerous. For 

these reasons, there is not sufficient data available to develop a numerical emission standard.

 

157 See CAA section 112(h)(1).

158 See CAA section 112(h)(2)(B).
168

Economic Limitations. Commenter 0162 stated that if EPA were to eliminate the excess 

emission provisions, mills would need to install duplicate systems for collection and treatment of 

both NCG gases and condensates. This includes:

 Installing equipment to send HVLC gases to a backup control device (assuming the 

facility has an available control device that can be used as a backup),

 Installing redundant HVLC and LVHC gas collection systems, and/or

 Installing back-up steam strippers.

The commenter estimated that the costs to install these systems is $1.6 billion, which is 

cost-prohibitive and unnecessary, given that EPA has determined that the risks associated with 

the current rule, which included emissions during venting, are acceptable. The commenter noted 

that, even with these installations, there is no guarantee that a mill would be able to prevent all 

incidents of stripper downtime and/or venting due to process variability and safety concerns. The 

commenter provided the breakout of their cost estimate in Table 9 below and included additional 

details in Attachment 5 of their comment (0162). 

Table 9. Capital Cost Estimate for Redundant Systems

(Submitted by Commenter 0162)

System Capital cost

HVLC Redundant Control Costs $ 500 M

Redundant LVHC/HVLC Collection Systems $ 700 M

Back-Up Strippers $ 400 M

TOTAL $ 1.6 B

Response: We appreciate the information provided by the commenter regarding a 

justification for replacing the excess emission allowances with a work practice (if necessary) and 

the technological and economic limitations associated with other regulatory approaches. We will 

use this information, as well as information we received from industry to further investigate 

these allowances. We will take action on the excess emissions allowances at a later date.

113 Comment: Several other commenters (0163, 0167, 0170, 0207, and 0212) were also 

opposed to elimination of venting and stripper downtime allowances, and provided similar 

arguments to those presented above.

Commenter 0163 opposed removal of the excess emissions allowances because they are 

necessary for the safe and orderly operation of mill processes and were included as part of the 

original MACT floor and are reflective of the best-performing mills. The commenter noted that 

EPA proposed in the December 27, 2011 rulemaking to remove language that excludes SSM

events from the LVHC and HVLC allowances and includes such SSM events in the steam 

stripper venting allowance. The commenter opposed these changes until such time that EPA 

receives and adequately evaluates the information that it has requested concerning industry and 

state practices. The commenter stated that they have not had enough time to evaluate and prepare 

responses to the information requests concerning the allowances. The commenter understood

from NCASI that EPA will accept this information until June 27, 2012.

Commenter 0167 stated that emission allowances represent the MACT floor 

determination and are necessary to account for emissions during unavoidable periods of releases 
169

of uncontrolled or partially uncontrolled pulping process vent gases and unavoidable sewering of 

untreated or partially untreated pulping process condensates. Without the emission allowances, 

the remainder of the subpart S emission standards would impose limitations not achievable by 

the best performers and not demonstrated at any facility. The commenter stated that the EPA has

provided no technical justification for eliminating these allowances. The commenter stated that 

the EPA has the obligation to evaluate the residual risk from individual MACT categories, as 

well as identify any technology improvement, and the EPA does not provide any justification 

from either.

Commenter 0170 stated that elimination of vent and downtime allowances, as considered 

in the proposal, would make process gas destruction requirements unachievable, even with 

construction of new redundant control systems at great cost and little benefit, during periods 

when venting to the atmosphere is necessitated in order to comply with insurance and process 

safety codes, to protect equipment and to ensure a safe work environment for employees.

Commenter 0207 stated that a limited amount of venting of NCGs consisting of LVHC

and HVLC streams must take place in the course of daily operations, as well as in startup and 

shutdown of processes. These short periods of excess emissions are not “malfunctions” in any

real sense. They are part of the design and proper operation of the equipment covered under the 

rule. The commenter stated that facilities should not have to resort to defending these 

unavoidable events from enforcement. The commenter stated that allowances for some excess 

emissions are necessary for safe, efficient, and environmentally responsible operation of the 

array of equipment employed for HAP collection and control. These systems are closely 

integrated into complex pulping and combustion operations.

Commenter 0207 stated that the EPA has presented no evidence demonstrating that 

limited venting results in increased health risks or environmental impacts. The commenter 

contended that the Agency has not justified the need for their company and others to spend 

enormous amounts of money to install backup, redundant or “upgraded” equipment to reduce 

venting further. The commenter urged the EPA to retain the subpart S venting allowances. The 

commenter stated that if the Agency wanted to revisit venting of LVHCs and HVLCs, it should 

examine the data the industry’s mills submitted as part of their quarterly or semiannual 

compliance reports, as well as any other pertinent information the industry can supply before the 

rule is finalized. The commenter contended that the data would support the company’s position 

that some venting is necessary and acceptable. The final version of the rule should provide 

adequate venting allowances for control equipment and for limited venting during startup and

shutdown of some processes. Many such events do not meet the common-sense definition of 

“malfunction.”

Response: We appreciate the commenters’ concerns regarding the removal of the excess 

emission allowances. We will use this information, as well as information we received from 

industry to further investigate these allowances. We will take action on the excess emissions 

allowances at a later date.

The EPA views the amendments to remove the SSM exemption (through corrections to 

General Provisions references) as a separate issue from the excess emissions allowances. If, upon 

further analysis of the information provided by industry, we find reasons to distinguish between 
170

startup/shutdown periods and normal operations in the context of our approach for handling the 

excess emissions allowances, then we will address those concerns when we propose our findings 

relative to the excess emissions allowances. However, for today’s action, EPA considers the 

SSM exemption a separate issue decoupled from the excess emissions allowances and is 

proceeding with removal of the SSM exemption.

8.1 LVHC Systems (1 Percent)

114. Comment: Commenter 0162 stated that LVHC NCG gases are potentially explosive and 

cannot be burned safely without supplemental fuel. Most mills have both a primary and back-up 

control device159 for the treatment of LVHC gases. These gases must be incinerated with support 

fuel and be interlocked to failsafe on loss of support fuel, combustion air, and/or boiler load. The 

flame safety system will not permit the gases to be admitted until the burner is operating on 

supplemental fuel and ignition is proven. Therefore, for gases to be introduced into any control 

device, several conditions, also known as permissives, must be met and the system has a series of 

interlocks that will not allow the introduction of gases unless all conditions are satisfied. These 

conditions are required for both safety and protection of process equipment. The safety interlocks 

are required by both Factory Mutual Insurance and the National Fire Protection Association for 

burning of these non-condensable gases. Also, when these gases are burned in a recovery

furnace, there are safety guidelines issued by the Black Liquor Recovery Advisory Committee. 

Depending on the control device, the system may have anywhere from nine to fifteen interlocks.

The commenter stated that the most common cause of an LVHC release is due to the loss 

of a flame or burner permissive for the control device. These events are typically short in 

duration and the situation quickly resolves itself. An example is an intermittent loss of burner in 

the destruction device due to loss of flame or flame scanner detection temporarily during 

cleaning of oil gun(s) on oil fired unit. Safe destruction of LVHC gases requires the presence of a 

burner in the destruction device for safety reasons to assure combustion of the gases. In most 

cases, the permissive allows a return to normal operation in less than five minutes. In cases 

where this does not occur, the mill would try to transfer treatment of the gases to the back-up 

control device.

The commenter stated that, in situations where the back-up control device is not 

immediately available (i.e., due to maintenance, the back-up system is not “hot”, etc.), the mill 

must analyze the situation and decide how to minimize emissions. If the mill anticipates the 

permissive will allow a return to normal operation in a reasonable amount of time, the facility

will continue to operate rather than to implement an emergency shutdown that could result in 

higher emissions. If this is not the case, the mill will shutdown the subpart S sources. Most states 

recognize this situation in that they allow facilities to run for a period of 1 – 4 hours (depending 

on the state) with the control device down before requiring notification and corrective action. 

The commenter provided the following examples of events that can cause the isolation of the 

destruction device and venting of the LVHC NCG stream:

 Low steam supply pressure to the inductor, or

 Low steam flow to the inductor, or

 

159 Common control devices for LVHC gases include power boilers, lime kilns, stand-alone thermal oxidizers, and 

recovery furnaces.
171

 Low inductor outlet NCG flow, or

 Low inductor inlet vacuum, or

 High temperature downstream of inductor (flashback), or

 NCG nozzle pressure is inadequate (ensures proper furnace penetration), or

 Loss of main NCG header rupture disc, or

 A pressure instrument detects a high pressure event, or

 Main vent or double block and bleed valve vent valve not showing closed by limit switch, 

or

 Main auxiliary-fuel valve failure to open, or

 Loss of destruction device BMS permissive, or

 Low destruction device temperature, or

 Dedicated destruction devices:

o Loss of quencher permissives

o Loss of scrubber permissives

o Incinerator—quencher outlet temperature high-high alarm

 Any other condition relating to the safe operation of a destruction device

Another cause of unplanned releases is process variation. During these events, there is a 

vent at the process source until the operator or process logic control system can verify that there 

has not been an explosion in the system and the permissives will allow collection of the vent. In 

these situations, the system is operating within its design parameters and repairs are not 

necessary. An example is a paper machine trip which causes a domino effect throughout the mill 

(i.e., the machine trip causes a swing in the steam header pressure which results in over 

pressurization at the pulping equipment and a vent to open to relieve the pressure and prevent an 

explosion). The NCG system (LVHC or HVLC) will also automatically vent gases to atmosphere 

for any of the following process reasons associated with collection of individual sources which 

also typically cause the collection system main vent location to open by-passing the control 

device: high temperature, high pressure, or bypass rupture disc ruptured.

Response: We appreciate the commenters’s concerns regarding the excess emission 

allowances for LVHC systems. We will use this information, as well as information we received

from industry to further investigate these allowances. We will take action on the excess

emissions allowances at a later date.

8.2 HVLC Systems (4 Percent)

115. Comment: Commenter 0172 noted that when subpart S was promulgated in 1998, EPA 

recognized that existing HVLC systems in the industry did not have backup control devices and,

therefore, established a 4 percent venting allowance for those times when the sole control device 

was shut down for maintenance. Stated differently, backup control for HVLC systems was not 

part of the MACT floor. The commenter contended that this is still true today, as most mills have 

not installed backup HVLC controls. As previously noted, the floor cannot be modified without 

demonstrating there have been “developments in practices, processes and control technologies.”

If EPA were to eliminate the 4 percent HVLC venting allowance, this would be a de facto

mandate for mills to install a backup control device to be in continuous compliance with the new 
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standard (i.e., continuous collection and destruction without an excess emission allowance). The 

EPA has not conducted a beyond-the-floor analysis to justify this approach.

Commenter 0162 stated that the HVLC system is similar to the LVHC system in causes 

of venting events.160 The commenter explained that the main difference is that most HVLC 

systems do not have back-up control devices. Therefore, when the permissive prevents treatment 

of the gases, the mill must decide if emissions will be best minimized by waiting for the control 

device to become available or shutting down the HVLC sources. The commenter provided the 

following examples of events that can cause the isolation of the destruction device and venting of 

the HVLC NCG stream:

 Loss of HVLC fan, or

 Low HVLC fan outlet flow, or

 Low HVLC fan inlet vacuum, or

 High temperature downstream of HVLC fan (flashback), or

 Loss of main NCG header rupture disc, or

 A pressure instrument detects a high-pressure event, or

 HVLC vent valve not showing closed by limit switch, or

 Loss of destruction device burner management system permissive, or

 Low destruction device temperature, or

 Any other condition relating to the safe operation of a destruction device.

Commenter 0162 stated that EPA recognized that most of the MACT “floor” mills 

controlling HVLC sources did not have back-up control devices, and, therefore, EPA provided 

for a longer excess emission provision under the rule. The commenter noted that, due to the 

volume of HVLC gases, the control options are typically limited to either a stand-alone 

incinerator, power boiler, or recovery furnace, and the gases are injected as combustion air.

Response: We appreciate the information provided by the commenters regarding the 

excess emission allowances for HVLC systems. We will use this information, as well as 

information we received from industry to further investigate these allowances. We will take 

action on the excess emissions allowances at a later date.

8.3 Steam Stripper Systems (10 Percent)

116. Comment: Commenter 0172 stated that a steam stripper excess emission allowance is 

essential for pulp mill process equipment. As with control devices for HVLC systems described 

above, when subpart S was promulgated EPA recognized that steam strippers, even at the best 

performing sources, required periodic routine maintenance. Because backup condensate 

treatment was not considered as part of the MACT floor at these facilities, EPA established a 

10 percent excess emission allowance to cover periods of required maintenance. Should EPA 

eliminate this allowance, facilities would be required to install a backup system to treat process 

condensates when the steam stripper was shut down for routine maintenance. The only options 

 

160 “The best-performing mills achieve a four percent downtime in the control devices used to reduce emissions from 

their HVLC system to account for flow balancing problems and unpredictable pressure changes inherent in HVLC 

systems” (See 63 FR Vol. 72 at 18529 (April 15, 1998))
173

for backup control would be to install a new stripper (the commenter cited EPA’s estimate of 

$5.3 million for a new stripper) or hardpipe condensates to the wastewater treatment system. In 

addition to the cost of installing the necessary piping systems, hardpiping may not be feasible at 

all waste treatment plants without significant capital expense to improve aeration capacity or 

even enlarge the footprint of the system. As with HVLC systems, EPA has not done a beyondthe-floor analysis to justify this approach. 

Commenter 0162 stated that, under the existing MACT standards for both steam strippers 

and stand-alone biological treatment systems that treat only condensates, periods of excess 

emissions are not violations, provided that such periods do not exceed 10 percent of the total 

process operating time in a semi-annual reporting period. (See §63.446(g).) This provision was 

included in the current rule because the MACT “floor” mills did not have back-up control 

devices and could not treat condensates at all times.161 The 10 percent excess emission allowance 

includes SSM events, and the commenter asserted that it should continue to include SSM events 

because there is no backup for these systems. These systems require maintenance, and when 

there are problems with their operation, the systems can require significant work to get them 

back to serviceable condition.

Response: We appreciate the information provided by the commenters regarding the 

excess emission allowances for steam strippers. We will use this information, as well as 

information we received from industry to further investigate these allowances. We will take 

action on the excess emissions allowances at a later date.

 

161 “The appropriate excess emissions allowance for steam stripper systems was determined to be 10 percent. The 

provision accounts for stripper tray damage or plugging, efficiency losses in the stripper due to contamination of 

condensate with fiber or black liquor, steam supply downtime, and combustion control device downtime. This 

downtime provision includes all periods when the stripper systems are inoperable including scheduled maintenance, 

malfunctions, startups, and shutdowns.” (See 63 FR 18530 (April 15, 1998)).
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9. Testing and Monitoring

117. Comment: Commenters 0162 and 0207 objected to the proposed new revision in 

§63.457(o), which states that performance tests shall be conducted under “such conditions as the 

Administrator specifies to the owner or operator based on representative performance of the 

affected source for the period being tested. Upon request, the owner or operator shall make 

available to the Administrator such records as may be necessary to determine the conditions of 

performance tests.” The commenters argued that, depending on what “conditions” the 

Administrator specifies, it may be impossible to conduct performance testing in the time frame 

required, while simultaneously meeting all the conditions the Administrator or her designee may

specify. The commenters stated that this new provision makes it unnecessarily difficult to 

develop testing protocols and successfully conduct performance tests.

According to the commenters, performance tests should be conducted under normal 

operating conditions, taking into account real-world constraints and considerations. To illustrate 

this argument, commenter 0162 noted that the actual load or capacity to which any digester, pulp 

washing line, or bleach plant (and their supporting steam stripper or wastewater treatment plant) 

can operate depends on the capacities of tanks holding pulp and the demand for pulp from pulp 

and paper machines (unless the pulp is discharged to the sewer, a highly undesirable outcome). 

According to the commenters, a number of other short-term process fluctuations and unplanned 

events can have an impact on pulp production and supporting operations.

The commenters stated that mills provide stack test notice 60 days in advance and plan 

for stack tests in good faith to run under conditions that represent normal operation. The 

commenters noted that normal operation includes many load conditions and load mixes at mills 

with multiple lines. The commenters concluded that the rule should simply require that 

performance tests be conducted under normal operating conditions.

The commenters noted that special conditions and alternative operating scenarios (such 

as running only one scrubber in a series of two scrubbers) are addressed in part 70 operating 

permits, which also address the compliance demonstration requirements for these scenarios.

Response: We do not agree that these requirements make it impossible to conduct the 

performance test or unnecessarily difficult to develop the test protocol. The language specifying 

the conditions under which the performance tests are to be conducted is typical of those 

conditions specified for many processes and control measures, which can vary greatly. The 

Agency understands that some processes may present unique challenges in specifying a narrow 

range of process conditions and control device operating conditions under which the 

performance test must be performed. However, this does not preclude the facility from providing 

to the regulatory authority in the test protocol or test plan the range of operating conditions and 

control device conditions which they expect to exist at the time of the performance test. By

having facilities provide the expected test conditions and supporting rationale that these 

conditions are representative of the facility’s emissions performance, the regulatory authority can 
175

determine whether these conditions are acceptable and consistent with the intent of the rule and 

the EPA’s CAA national stack testing guidance.

162

9.1 Repeat Testing

118. Comment: Commenter 0162 did not object to the proposal requiring performance testing 

once every 5 years for facilities that comply with standards in §63.446 using steam strippers. The 

commenter noted that facilities that use strippers are currently required to conduct an IPT and 

then monitor surrogate parameters against limits developed during the IPT. While the commenter 

noted that strippers are efficient systems when properly operated and maintained and believes 

that monitoring surrogate parameters is appropriate to indicate continuing stripper removal 

efficiency, the commenter did not object to EPA’s proposal to require performance testing every

5 years, noting that this would provide additional compliance documentation.

Response: The EPA proposed 5-year repeat testing for stripper off–gases, which are part 

of the LVHC system by definition. The EPA did not propose, and, therefore, is not promulgating 

regulatory language requiring repeat performance testing for process liquids in this action. 

However, EPA does intend to propose repeat process liquid testing for steam strippers in a future 

action addressing the excess emissions allowances as a result of the comments received stating 

that steam stripper performance can degrade over time.

119. Comment: Three commenter (0162, 0163, and 0172) agreed with EPA’s decision not to 

propose additional emissions testing for facilities that comply with the CCA approach, due to the 

complexity and difficulty of these compliance demonstrations (76 FR 81347). Commenter 0162 

noted that these compliance demonstrations generally require the testing of both gas and liquid 

streams on multiple operating systems. According to commenter 0162, this testing requires 

significant time and resources that are not easily coordinated. Commenter 0162 noted that, 

during the IPT for each facility using CCA, the facility has to demonstrate that the CCA 

approach would result in lower emissions than the traditional compliance approach for HVLC 

systems, and the facility also has to conduct monitoring to ensure continuing compliance. 

Commenter 0162 concluded that, while CCA is an alternative compliance approach, it is a 

conservative option and actually results in a higher treatment standard and thus lower emissions.

Commenter 0163 noted that CCA approaches are site-specific, and often complex. The 

commenter’s facility using a CCA has established a monitoring system adequate to assure 

compliance, based on the measured baseline and the initial performance demonstration. Absent a 

change in process configuration affecting condensate management, additional emissions testing 

would not provide any further assurance of compliance.

Commenter 0172 pointed out that it would also be inappropriate to require retesting of 

exempted systems (such as the knotting and screening 0.1/0.2 lb/ton exemption limit and decker 

water 400 ppm concentration limit) because these are not controlled systems and it would be 

very difficult to perform such retesting.

 

162 See memorandum from L. Lund, EPA Office of Compliance, to Regional Compliance/Enforcement Division 

Directors, Issuance of the Clean Air Act National Stack Testing Guidance, April 27, 2009, available online at: 

http://www.epa.gov/compliance/resources/policies/monitoring/caa/stacktesting.pdf.
176

Response: We acknowledge the commenters’ support for our proposal not to require 

repeat testing for CCA compliance. We considered the complexity of the CCA approach (e.g., 

comparison to baseline emissions calculations and the fact that it often involves both air and/or 

liquid sampling) in arriving at this decision. We estimated that repeating the CCA compliance 

demonstration would cost $130,000 per facility.

163

The repeat testing requirements in the final rule remain as proposed, with the exception 

of some clarifying language regarding test dates and equipment exempt from repeat testing. The 

final rule clarifies that the first of the 5-year repeat tests must be conducted within 36 months (3 

years) of the effective date of the standards, and thereafter within 60 months (5 years) from the 

date of the previous performance test for facilities complying with the standards for kraft, soda 

and semi-chemical pulping vent gases (§63.443(a)); sulfite processes (§63.444); and bleaching 

systems (§63.445). Quarterly sampling for biological treatment systems to demonstrate 

compliance with the kraft condensates standards in §63.446(e)(2) is already required under 

subpart S. 

We have added clarifying language to the repeat testing requirement in §63.457(a)(2) in 

the final rule to address commenter 0172’s statement about knotters, screens, and deckers 

exempted from the subpart S standards if they meet the HAP emissions criteria specified in 

§63.443(a)(1)(ii) or (iv). The clarifying language confirms that the 5-year repeat testing is not 

required for knotter or screen systems exempted from the standards based on the criteria 

specified in §63.443(a)(1)(ii)(A) through (C), or for decker systems exempted from the standards 

based on the criteria is §63.443(a)(1)(iv)(A) or (B).

120. Comment: Commenter 0218 stated that the EPA must implement strong enforcement 

provisions to prevent emission spikes, malfunctions and other violations in a way that will be 

enforceable by citizens in the title V permits for this source category. The commenter

recommended that the EPA require periodic testing that will assure compliance and show EPA, 

states, and the public whether or not the facilities are in compliance. The commenter mentioned 

the need for strict monitoring and enforcement provisions to enforce the permit condition 

requirements of the Act, and monitoring requirements that are stringent enough so that EPA, 

states, and citizens can easily access information permitting them to assess whether a facility is 

in full compliance with the standards within a short period of time of any violation. The 

commenter suggested that the EPA require performance tests every year instead of every 5 years, 

to stay up-to-date on the industry’s emissions and compliance status and allow states and citizens 

to gather data to assess and help assure compliance. The commenter also asked that the EPA 

require continuous monitoring of emissions from this source category to assure compliance.

Response: The EPA believes that periodic testing every 5 years is sufficient and costeffective for this source category. The EPA believes that the monitoring provisions are sufficient 

to ensure compliance between testing periods. Under the provisions of §63.15, the public can 

request access to reports submitted to the regulatory agency whenever they choose, with the 

exception of information protected through 40 CFR part 2 (e.g., confidential business 

 

163 See memorandum from T. Holloway, K. Hanks, and C. Gooden, RTI, to J. Bradfield and B. Schrock, EPA, titled 

Costs, Environmental, and Energy Impacts for the Promulgated Subpart S Risk and Technology Review, May 15, 

2012, in the docket for the subpart S rulemaking.
177

information). In addition, as discussed in Section 9.3 below, EPA is promulgating requirements

for electronic reporting of emissions test data that will improve public access to emissions 

information. 

9.2 Emissions Test Methods

121. Comment: Commenter 0162 noted that EPA has requested comment on the 

appropriateness of rederiving the equation in subpart S to demonstrate compliance with the kraft 

condensate standards for biological treatment, specifically, whether the equation should be 

rederived without MEK, since the current equation requires the sampling and analysis of MEK 

and that pollutant was removed from the HAP list in 2005 (76 FR 81347-81348). According to 

the commenter, evaluating this equation will not affect the residual risk assessment and has 

nothing to do with whether the technology has changed. The commenter recommended that this 

equation not be rederived. Commenter 0162 stated that they, along with NCASI, spent a 

significant amount of time and effort during the original rule development to derive equations 

that would best demonstrate compliance with the standard based on conservative estimates. The 

commenter noted that the approach assumes that non-methanol HAPs are not biologically treated 

and, therefore, the facility must treat an additional quantity of methanol. According to the 

commenter, this is a conservative approach and actually requires additional treatment by each 

facility, so it results in lower emissions.

Conversely, commenter 0228 stated that the EPA removed MEK from the list of section 

112 HAP in 2005, and it should not be included in subpart S calculations.

Response: As noted elsewhere by commenters, the value of the “r-factor” included in the 

biotrreatment system performance equation in §63.457(l) is typically around 0.02. The EPA 

reviewed the site-specific r-factor values reported in the ICR and agrees that this mass ratio of 

non-methanol HAPs to methanol HAPs is typically around 0.02, reflecting that approximately 2 

percent of the measured HAP are non-methanol HAP.164 MEK is a fraction of this 2 percent. We 

have decided not to discontinue inclusion of MEK in the §63.457(l) equation, given the small 

fraction of HAP that MEK comprises, the comment requesting that we retain the original 

equation, and the fact that retaining MEK does not reduce the stringency of the standard. 

122. Comment: Commenter 0225 stated that much of Port Townsend Paper Corporation’s

reported emissions are simply drawn from industry tables rather than from direct measurement. 

Attempts to retrieve emissions reports were unsuccessful. There is no point source registry, and 

the commenter stated they are unable to locate the central repository for criteria pollutant 

reporting. According to the commenter, a memo between the Regional Air and Washington Dept 

of Ecology attached to their comment indicates that PTPC is secure in refusing to provide certain 

emissions reports.

Response: A combination of emissions testing and emission factor calculations are 

commonly used to estimate emissions for purposes of mill emissions inventory development. 

This practice is not unique to PTPC. Specific emissions testing requirements are outlined in 

federal and state/local rules and permits. Due to the costs of air emissions testing, it is often not 

 

164 The average value of “r” reported in the ICR responses was 0.017, and the maximum was 0.06. 
178

practical to require emissions testing for every single pollutant. Emission factors (typically from 

NCASI Technical Bulletins) are often used for emissions inventory development when a sitespecific emissions test is not available for a particular process and pollutant. Otherwise, there 

would be gaps in the emissions inventory. However, mill-specific data in the form of operating 

factors (e.g., pulp production rates, black liquor solids firing rates, annual operating hours) are 

used to calculate the emissions for each mill. While we did not find the referenced attachment in

the docket, as stated in a previous response, under §63.15, the general public is able to request 

access to reports submitted to the regulatory agency whenever they choose, with the exception of 

information protected through 40 CFR part 2 (e.g., confidential business information). In 

addition, as discussed in section 9.3 below, EPA is promulgating requirements for electronic 

reporting of emissions test data that will improve public access to emissions information.

123. Comment: Commenter 0225 noted that under §§63.7(e)(2)(ii) and (f) and 63.8(f) of the 

NESHAP GP, a source may apply to the EPA for permission to use alternative test methods or 

alternative monitoring requirements in place of any required testing methods, performance 

specifications, or procedures in the final rule and any amendments. The commenter stated that at 

PTPC, alternate test methods allow them to use industry tables to estimate emissions OR reduce 

their testing to once a year at a time of their own choosing OR submit one test instead of three. 

Given that there is a low level of oversight, the commenter is not confident of the results of such 

testing. The commenter asked that provisions be included to be sure that any alternate test 

methods are grounded in actual emissions in a meaningful way.

Response: In this action, EPA is taking steps to amend 40 CFR part 63 subpart S in 

response to our findings relative to the residual risk and technology reviews. While we are 

adding provisions for 5-year repeat testing (as noted in previous responses), we are not adding

any changes to the alternative testing procedures in the NESHAP GP. The GP contain specific 

criteria that are to be used in evaluating requests for use of alternative test methods, changes to 

test methods, or a reduced frequency of testing. Regarding oversight, the EPA retains authority

for approval of alternative standards, alternative test methods, alternative monitoring methods, 

and alternative reporting/recordkeeping under §63.458 of subpart S. Regarding PTPC using 

industry tables to estimate emissions, as noted in a previous response, emission factors (typically 

from NCASI Technical Bulletins) are often used for emissions inventory development when a 

site-specific emissions test is not available for a particular process and pollutant. It is often not 

practical to require emissions testing for every single pollutant due to the costs of air emissions 

testing.

9.3 Electronic Reporting

124. Comment: Commenter 0162 argued that the proposed electronic reporting requirement is 

not justified and would be excessively burdensome to industry. The commenter noted that the 

owner/operator is required to submit the test data to EPA’s Central Data Exchange (CDX) by 

using the ERT when the data and methods are compatible with the ERT. According to the 

commenter, the performance tests conducted under subpart S are unique and unlike traditional 

stack tests, and the data collected and the standards that must be met are specific to the systems 

used to collect and treat condensates. The commenter also noted that there is no reason for EPA 

to require submittal of this test data because facilities are already required to submit performance 

test data to regulatory agencies and provide certifications on their semi-annual compliance 
179

reports that they have performed the required monitoring and will provide information on any

deviations from the testing requirements. According to the commenter, additional performance 

test reports provide no useful purpose, environmental or otherwise, to anyone and are an 

additional administrative burden on operating facilities. The commenter noted that ERT 

continues to be revised and updated due to various flaws, and that it would be unreasonable to 

put sources at risk of violations (late reporting) because of EPA reporting tool issues or 

availability. 

Commenter 0207 stated that the proposed §63.455(h) requires performance test reports 

and continuous emissions monitoring system relative accuracy test audits (CEMS RATA) to be 

submitted electronically to EPA’s WebFIRE database. The commenter noted that since it is 

likely that many states eventually will be delegated authority, this requirement is overly 

burdensome and costly for facilities with limited resources.

Both commenters (0162 and 0207) noted that a number of states already specify that 

performance test results be submitted in an electronic format and argued that EPA should remove 

its reporting format requirement from the rule and work more closely with states to develop a 

universal reporting system that is not costly or redundant, does not require different electronic 

reporting formats, and is not problematic and labor-intensive for data entry. According to the 

commenters, the rule’s requirement, as proposed, is an extra, excessive burden for mills and 

stack testing vendors. The commenters stated that EPA needs to defer any electronic collection 

of data until the CDX and WebFIRE systems are fully functional, user-friendly, and streamlined 

with states.

Response: The EPA agrees that there are some test methods used in this rule that 

currently cannot be documented using the ERT. The rule only requires the use of the ERT when 

the test methods are supported by the ERT. The EPA disagrees that test methods used to comply 

with this rule should not be documented. The EPA acknowledges that there may be existing 

reporting programs in place. However, the compliance test reporting requirement in this rule 

does allow for quick and easy access of the data by state, local, and tribal entities, as well as the 

public. As of January 1, 2012, the CEDRI has been fully functional. Since that time, ERT 

submittals via CEDRI and the CDX were transferred into EPA’s Webfire database, which is 

publicly accessible. WebFIRE provides a convenient location, which is already used to store 

source test data allowing regulatory authorities access to Cross Media Electronic Reporting Rule 

(CROMERR) compliant test reports. As EPA and state/local agency data systems mature, 

information provided through the ERT will be used to populate these data systems. We are 

currently upgrading the Aerometric Information Retrieval System (AIRS)/Air Facility System 

(AFS) and expect to replace manually entered information with electronic population from the 

ERT. We are also working with several state and local agencies to adopt the use of the ERT for 

delivery of compliance test reports. We disagree that all systems to receive and process the 

compliance data must be operational prior to establishing the requirement for regulated sources 

to submit compliance data electronically. 

125. Comment: Commenter 0163 was concerned with EPA’s proposal to require use of the 

ERT for electronic reporting. The commenter’s experience with this system during the Boiler 

MACT ICR surveys was poor. The commenter noted EPA is requesting information to be 

routinely reported for matters of convenience to Agency information gathering, which adds large 
180

burden to the permittees individually and as a whole. Regarding the effective date, the 

commenter’s facilities would need time to adapt reports to fit the format, and EPA needs to 

consider the time needed to avoid duplication of work for reporting to permitting agencies using 

different formats. The EPA, the states, and permittees will need time to work out compatible 

formats for such reporting.

Response: The EPA disagrees that the ERT is excessively burdensome. The 

commenter’s experience with the ERT used during the Boiler MACT ICR is not indicative of the 

current performance. The EPA has implemented many programming changes that address most 

of the issues users had with the version of the ERT that was available in 2009. Since the Boiler 

MACT ICR, there have been 27 revisions to either correct issues which users have encountered 

or to add test methods.

The EPA disagrees that the ERT requires the reporting of vast amounts of data that are

not currently required for convenience to the Agency’s information gathering. The commenter

may be confusing the presence of a data field as one that requires entry of data. Also, the 

commenter may be confusing the level of information the EPA required in the Boiler MACT 

ICR with what would be required for a compliance test report. The EPA made the ERT flexible 

to accommodate a wide variety of existing data requirements specified by various state and local 

agencies and specified in various published EPA test methods and published state and local 

agency test methods. The EPA does not expect sources to enter data into every available field of 

the ERT for every source test. The subpart S rule specifies the specific data which are required to 

be reported in the ERT. In addition, each state or local agency which has delegated authority has 

provided guidance on those data elements which they expect in compliance source tests. The 

commenter’s question about the effective date is addressed below in section 10 of this document.

126. Comment: Commenter 0218 supported the EPA’s proposal for electronic reporting, and 

asked that this apply to all emission and performance test data and other parameters that the 

standards use to gauge compliance. The commenter suggested that the required compliance 

records be reported at least annually to the EPA and the states, and ensure that these are made 

publicly available promptly. The commenter observed that, as the public has a right to all 

collected reports under the CAA, it is important that the EPA ensure immediate disclosure of 

these reports to the public on the Internet within 7 days of receipt of a report, without the need 

for any person to submit a request under the Freedom of Information Act. The commenter also 

asked that the EPA require continuous monitoring of emissions for compliance, and immediate

reporting on the Internet of all monitoring reports.

Commenter 0218 also asked that the EPA promulgate specific public reporting and 

notification requirements for malfunctions or any emission exceedances. The commenter noted 

that the EPA proposes to require malfunction reporting by telephone no later than 2 business 

days after the malfunction or exceedance, and to require a written report to EPA within 45 days. 

The commenter suggested that the EPA require this reporting regardless whether a facility

intends to try to take advantage of an affirmative defense (which EPA should not authorize). 

The commenter asserted that these reporting time periods are too long for people that are 

near the facility and asked that the EPA require telephone reporting by the facility no later than 

24 hours after the malfunction or exceedance, made publicly available on EPA’s website and 
181

through EPA’s Enforcement and Compliance History Online (ECHO) system within 24 hours.

The commenter recommended that the EPA Administrator provide this information to its 

Regional office within 24 hours of receiving notification, and direct the Regional office to notify

the local community on the Internet, by direct communication, and through all available means.

Further, the commenter asserted that the facility must provide community notification of the 

malfunction or emission standard exceedance within 24 hours, through an appropriate public 

forum (i.e., facility’s website, municipalities, schools, and local media) that contains any

information community members may need to try to protect themselves and their families from 

the additional air pollution.

The commenter recommended that the EPA require a written report to be submitted 

within 7 days to be distributed to the community, including publication on ECHO, and sending 

this to active local community members through electronic and other media. The commenter 

asked that the report include: (1) the nature of the event; (2) the duration of the event; 

(3) estimate of emissions released during the event; and (4) a description and timing of corrective 

actions that were taken and any planned to be taken.

Commenter 0218 also asked that the EPA promulgate additional requirements that apply

in the event of a malfunction or violation of the numerical emission standards so that facilities 

are not allowed to emit in an unlimited manner for an unlimited period of time. The commenter 

recommended further actions in the case of an exceedance or malfunction:

1. The EPA must require automatic shut-off of the malfunctioning equipment or process for 

the time needed to take corrective action, whenever an exceedance or malfunction occurs.

2. The EPA must assign responsibility and liability to the plant manager or a high-up staff 

member to allow only that person to restart the equipment or process.

3. The EPA must require specific corrective measures to be taken immediately, to remedy

and prevent recurrence of the malfunction or violation.

4. For a facility that has had one or more malfunction, exceedance, or other violation 

incident in the prior month, written authorization by EPA must be required to restart 

equipment or processes. The EPA should only authorize restart after making a public 

determination that provides information on the corrective measures that EPA is requiring. 

The EPA should release this public determination on the Internet and require its Regional 

office to communicate this determination to all interested members of the public, 

including local community representatives.

5. If a facility has more than 4 exceedances or malfunctions during the same quarter, then

EPA must require automatic shut down of the operation for a period of time needed to 

conduct and publish a full investigation and ensure systematic correction of the problems.

6. The EPA should create a community complaint mechanism in the standards that ensure 

that a citizen complaint of clouds, plumes, exceedances, odors, other air pollution 

incidents or health concerns receive an immediate response from EPA’s enforcement 

division within 7 days, in which EPA commits to initiate an investigation and provide a 
182

publicly available report of the result of the investigation, including whether it leads to an 

enforcement outcome.

Response: As of January 1, 2012, the EPA has provided almost immediate access to ERT 

submittals through WebFIRE. The compliance test reporting requirement in this rule allows for 

quick and easy access of the data by state, local, and tribal entities, as well as the public. As of 

January 1, 2012, the CEDRI has been fully functional. Since that time, ERT submittals via 

CEDRI were transferred into EPA’s Webfire database. While this information does not cover all 

the information which the commenter has identified, EPA’s intentions are to expand the types of 

performance test data which the ERT is capable of documenting and to develop an electronic 

submission method for other types of compliance data. In addition, EPA is modernizing the 

AIRS/AFS data system, which is EPA’s primary air compliance reporting data system (which 

may include publication on ECHO), with plans to integrate the data between WebFIRE and 

AIRS/AFS. Since the development of the compliance reporting methods and the AIRS/AFS 

modernization are early in their development, it is unclear the timelines that will be adopted. It is 

likely that the timelines for availability of information will be shorter than the existing timelines.
183

10. Compliance Dates

127. Comment: Three commenters (0162, 0163, and 0207) objected to the different 

compliance dates included in the proposed rule. The commenters noted that the proposal (at 76 

FR 81349) requires existing sources comply with proposed affirmative defense and electronic 

reporting provisions upon promulgation and comply with all other proposed requirements within 

3 years after the effective date. The commenters supported setting the compliance date at 3 years 

after the effective date for all new requirements.

To the contrary, commenter 0218 stated that delay of compliance for the new standard for 

3 years is unlawful and arbitrary. The commenter argued that in enacting the provision governing 

the compliance schedule for section 112(d), Congress stated that it wanted expeditious

compliance. The commenter asserted that the EPA has failed to demonstrate that this 3-year 

MACT compliance date for existing sources would provide for compliance as expeditiously as 

practicable, and, by failing to begin this rulemaking earlier, the EPA has already delayed 

satisfying its legal duties under sections 112(f)(2) and 112(d)(6) to provide protection for 

affected local communities. The commenter stated that, in light of the statutory context and 

circumstances mandating promulgation of a rule in 2006, EPA has no lawful justification for 

delaying the compliance date any longer.

Response: We have reviewed the comments and clarified the compliance dates in the 

final rule as follows: 

1. The date 36 months (3 years) after the effective date of the final rule for conducting 

the first 5-year repeat test;

2. The date 60 months (5 years) from the date of the previous performance test is the 

date for conducting the next 5-year repeat test;

3. The date 60 days following the completion of the performance test is the date for 

submitting the performance test results to the ERT; and 

4. The effective date of the final rule (i.e., date of publication in the Federal Register) is 

the compliance date for the SSM changes (including the affirmative defense 

provisions).

Comments relating to the SSM provisions and electronic reporting are addressed in more 

detail in the next response. We believe there are compelling reasons for allowing additional time 

beyond the final rule effective date to comply with the repeat testing requirements and electronic 

reporting requirements, and therefore, have elected to establish two compliance dates rather than 

one.

The repeat testing requirements we proposed apply for the kraft, soda, and semichemical 

pulping vent gases (§63.443), sulfite pulping vent gases (§63.444), and bleaching systems 

(§63.445). Facilities will need time to prepare and submit for approval their test plans for the 

5-year repeat emissions testing. Facilities and permitting authorities will likely need time to 

synchronize the new subpart S repeat testing requirements with the repeat testing schedule 

specified in permits (where applicable). Therefore, we believe that 36 months (3 years) is as 

“expeditiously as practicable” to implement the repeat emissions testing requirements, and the 

results would be reported to the ERT 60 days later.
184

128. Comment: Compliance date for SSM changes. Commenter 0162 noted that the 

elimination of the SSM provisions would apparently be effective immediately upon 

promulgation. The commenter stated that EPA has not really assessed the effect of eliminating 

that provision, because it could require mills to make significant changes to their HAP collection 

and treatment systems, such as installing redundant equipment not currently required, which 

would take significant time for design, engineering, acquisition, and installation. The commenter 

argued that there was no justification for making such a change in the existing regulations 

effective immediately, as EPA has proposed.

Commenter 0163 stated that the proposed affirmative defense provisions for 

malfunctions, assuming EPA finalizes them, will require substantial time after the final rule is 

issued to evaluate and understand the final rule provisions, review and understand what changes 

are needed to their existing procedures to implement those provisions, prepare and/or revise 

existing procedures and other documents as necessary, provide operator training, and then 

implement the changes. These are not insignificant process management and training changes,

and the commenter believes that EPA has underestimated needed transition time to implement 

them. The commenter noted the likelihood that judicial challenges of the affirmative defense 

provision may be filed as under other MACT rules where EPA is inserting the approach. Given 

the significant process management changes required, EPA should consider delaying compliance 

until the judicial outcomes are settled, in order to minimize confusion and disruption.

Commenter 0207 stated that, unless EPA leaves the rule as is, many mills will have to 

physically modify their operations to comply with additional performance requirements. 

Simultaneously, companies will have to re-visit process control parameters (e.g., burn 

permissives) and install additional hardware and software to monitor processes, collect data, 

classify events, and generate internal and externally-mandated reports. This would come at 

significant cost that was not included or evident in EPA’s cost estimates. The commenter stated 

that at least 3 years are needed to fund, engineer and complete these interrelated efforts.

Response: We disagree that there is no justification for making rule changes that 

eliminate the SSM provisions effective upon promulgation. The D.C. Circuit Court vacated the 

SSM provisions in December 19, 2008. In the interim, prior to the Court’s mandate of the SSM 

vacatur, EPA issued a letter dated July 22, 2009 from Adam Kushner, Director, Office of Civil 

Enforcement, to various parties that addressed concerns that had been raised regarding the

impact of the decision in Sierra Club v. EPA, 551 F.3d 1019 (DC Cir. 2008). The mandate 

implementing the Court’s decision was issued on October 16, 2009, at which time the SSM 

provisions were clearly no longer in effect. In addition, amendments to subpart S were proposed 

on December 27, 2011, at which time mills were put on notice of the specific wording changes to 

subpart S. Thus, facilities have had ample notice that EPA would remove the SSM exemption.

Based on Group I RTR draft p. 38 Regarding the time needed to implement the 

affirmative defense provisions for malfunctions, facilities have had practices in place to 

minimize emissions during malfunctions at least since the compliance date of the original MACT 

standards. Since the affirmative defense against civil penalties for violations of emission limits 

that are caused by malfunctions is available immediately, we believe facilities will either be able 

to meet the emission standards during malfunctions or will be able to use the affirmative defense 

upon the effective date of this rule.
185

Regarding the “likelihood that judicial challenges of the affirmative defense provision 

may be filed,” we note that EPA cannot predict judicial filings and the CAA does not explicitly

allow time for judicial proceedings to complete before a rule becomes effective. 

Contrary to commenter’s assertion that EPA ignored costs of the SSM revisions, EPA’s 

proposal cost analysis included a one-time cost to revamp existing recordkeeping systems to be 

consistent with the proposed revisions to the startup and shutdown provisions, and included costs 

for affirmative defense. These costs were derived from the PRA supporting statement developed 

for proposal.165,166 These costs have also been included in the final cost analysis and supporting 

statement.

129. Comment: Commenter 0162 was confused by the ERT submittal dates in the proposed 

rule. According to the commenter, section IV.E of the proposal preamble (“Compliance Dates,” 

at 76 FR 81349) states that electronic reporting is “effective upon promulgation of the final rule,” 

but the revised §63.335(h)(2) states that “As of January 1, 2012 and within 60 days after the date 

of completing each performance test, you must submit performance test data, except opacity

data, electronically to EPA’s Central Data Exchange (CDX) by using the Electronic Reporting 

Tool (ERT)...” The commenter stated that this language was confusing because it could be 

concluded that, once the rule is effective, all test reports since January 1, 2012 should have been 

submitted within 60 days of testing prior to the rule being effective.

Commenter 0163 stated that the performance tests and CEMS quality assurance tests 

would be required to be submitted before the close of business on the 60th day following the 

completion of the performance test and, except for opacity data, the data must be submitted 

electronically to EPA’s CDX by using the EPA’s ERT. The commenter believes neither the 

proposed electronic reporting nor manual reporting of performance tests should be retro-effective 

back to January 2012, nor should the reporting requirement become effective on the final rule 

effective date.

Response: The EPA agrees that there should not be a retro-effective test reporting 

requirement, as the commenter believes was required in the proposed rule. The date of January 1, 

2012 was included because of the expected date that EPA’s CDX could accept ERT submissions.

We have revised the electronic reporting requirement dates to agree with the testing requirements 

established in the rule. The compliance date for the repeat testing requirement is 36 months (3 

years) after the effective date of the final rule. The results of repeat tests (or other performance 

tests used to show compliance with subpart S) performed using methods supported in the ERT 

are required to be submitted to the ERT before the close of business on the 60th day following 

the completion of the performance test.

 

165 See memorandum from T. Holloway, K. Hanks, and C. Gooden, RTI, to J. Bradfield and B. Schrock, EPA, titled

Costs and Environmental and Energy Impacts for Subpart S Risk and Technology Review, November 17, 2011, in 

the docket for the subpart S rulemaking.

166 See U.S. EPA, Supporting Statement: NESHAP for Pulp and Paper Production (40 CFR Part 63, Subpart S) 

(Proposed Amendments, November 2011.
186

11. Regulatory Impacts

130. Comment: Cost Impact to Comply with 94 Percent Treatment Efficiency. Commenter 

0162 argued that EPA underestimated the cost impact to comply with the 94 percent kraft 

condensate treatment efficiency provision in the proposed rule. The commenter noted that EPA 

estimated the capital cost of the proposed modifications to the condensate standards at $36 

million and projected annual cost at $4.1 million ($1,000/ton HAP), based on 7 mills needing to 

upgrade their biological treatment systems and 8 mills needing to upgrade their steam 

strippers.167 The commenter believed the capital cost to meet an increase in required treatment 

efficiency from 92 to 94 percent would be closer to approximately $300 million (approximately

$150 million annually, or $38,000/ton HAP). The commenter noted that their cost estimates are 

based an increase in condensate treatment only, using their methodology for the equivalent 

lb/ODTP treatment (10.4/6.8 lb/ODTP), and not the lb/ODTP limits (12.8/8.3 lb/ODTP) 

proposed by EPA that are not achievable without additional collection. The commenter pointed 

out that most of the emission reductions would be methanol, which the commenter said does not 

present a risk, according to EPA’s own risk analysis, and is of relatively low toxicity.

According to commenter 0162, EPA did not include any information in the preamble to 

the December 27, 2011 proposed rule or in the docket describing how EPA expected mills to 

comply with the new standards, so the commenter carefully examined what would be necessary 

to comply with the proposal. The commenter noted that all cost estimates in their comment are 

based on the best information available, given the limited time to gather data during the 60-day

comment period, and were developed using conservative estimates of upgrades and number of 

units affected and not detailed mill-by-mill engineering estimates. The commenter pointed out 

that, even with these caveats, their cost estimates are an order of magnitude higher than EPA’s. 

The commenter acknowledged that these estimates are somewhat different from those presented 

to EPA on January 12, 2012 because they made further refinements and gained more information 

from member companies since that time.

Commenter 0162 noted that EPA estimated that a change in treatment efficiency from 92 

to 94 percent would result in the reduction of 4,000 tons of HAP from the industry per year (76 

FR 81345, 81349). The commenter stated that this estimate assumes that all 97 mills achieve a 

0.2 lb/ODTP HAP reduction, at a production rate of 1,000 ODTP per mill per day, but the 

commenter noted that EPA estimated only 15 mills would be required to spend capital to comply 

with the proposed standard.

168 According to commenter 0162, the 15 mills for which EPA 

generated an estimated compliance cost would only achieve a total estimated annual HAP 

reduction of 547 tons (0.2 lb/ton x 1000 tons per day (tpd) x 365 days per year (d/yr) x 15 mills / 

2000 lb/ton). According to the commenter, if EPA was inaccurate in its assessment of the 

number of mills that would need to make upgrades to meet the proposed 94 percent reduction 

requirement and the cost for them to do so, then the correct estimated cost/ton would be 

$7490/ton, rather than the $1000/ton stated by EPA. Commenter 0162 noted that even that cost 

per ton (to control mostly methanol) is much lower than what they believe would be the true cost 

 

167 See memorandum from T. Holloway, K. Hanks, and C. Gooden, RTI, to J. Bradfield and B. Schrock, EPA, 

titled,Costs and Environmental and Energy Impacts for Subpart S Risk and Technology Review, November 17, 

2011, in the docket for the subpart S rulemaking. (“EPA 11/17/2011 Cost Document”).

168 Id.
187

per ton of increasing required condensate treatment from 92 to 94 percent efficiency, as shown 

below.

As noted elsewhere, the commenter believes that EPA incorrectly calculated the proposed 

lb/ODTP treatment standards that are equivalent to 94 percent. For the purposes of this estimate, 

the commenter assumed that the treatment standards equivalent to 94 percent are 10.4/6.8 

lb/ODTP (bleached/unbleached). As shown in Table 10 below, the commenter estimated that 

total capital costs would be approximately $320 million, with annual costs of approximately 

$150 million, or $38,000/ton (using the same 4,000 tons of reductions identified by EPA).

Table 10. Costs of Proposed Condensate Treatment Standards

(Assuming Nominal 2 Percent Change in Treatment Efficiency)

(Submitted by Commenter 0162)

Capital 

Cost

Annualized 

Capital169

Annual 

Energy Cost

Annual 

Maintenance 

Cost

Total 

Annual 

Cost

Stripper Upgrade $ 94 M $ 8.8 M $ 8 M $ 3 M $ 20 M

Current Strippers 

(Energy Only)

$ 8 M $ 3 M $ 11 M

Aeration $ 230 M $ 21.6 M $ 90 M $ 9 M $ 121 M

Nutrient Addition $ 2 M $ 2 M

Total Cost $ 324 M $ 30.4 M $ 106 M $ 17 M $ 154 M

According to commenter 0162, the costs were based on the following (and further 

detailed in an attachment to their comment):

 The commenter projected that upgrades to both steam strippers and wastewater treatment 

systems will result in control systems that can achieve the required treatment efficiencies.

o According to the commenter, achieving higher treatment efficiency in steam strippers 

will require more energy, trays, and steam contact area per incremental percent 

reduction.

o The commenter noted that their estimates assume the 10 percent downtime provision 

for steam strippers remains in place; otherwise, the commenter indicated a back-up 

control device (at a minimum) would be needed, which the commenter said would 

significantly raise costs.

o For wastewater treatment systems, the commenter assumed that an increase in 

aeration and nutrient addition would be sufficient to achieve the requirements. For 

reasons described above, the commenter noted that wastewater treatment systems are 

currently required to target treatment levels close to 99 percent to comply with the 

current standard of 92 percent. According to the commenter, as required efficiency

increases, upgrading the wastewater treatment systems will become technically

infeasible and cost prohibitive. The commenter argued that, in many if not most 

 

169 Capital costs annualized using the same 0.094 capital recovery factor EPA used, see EPA 11/17/2011 Cost 

Document, p. 4.
188

cases, it will not be feasible to respond to increased required treatment efficiency

through upgrading the condensate collection and wastewater treatment system, and 

said that the mill would most likely decide to install a new stand-alone steam stripper, 

at much higher cost than estimated. However, to be conservative, the commenter 

assumed that all 39 mills that use only the WWTS as a condensate control device will 

only need increased aeration and nutrient addition to achieve a 94 percent control 

efficiency.

 The commenter used a cost of $2.9 M each for steam stripper upgrades, based on 

information from member companies, rather than EPA’s assumed cost of $2.7 M. 

 The commenter noted that strippers can either be stand-alone units or integrated and 

indicated that, based on initial input from their members, they identified 10 integrated 

units. Because the total number of strippers being used for subpart S compliance is 52, 

the commenter assumed that 20 percent of strippers that required upgrades were 

integrated and the remaining 80 percent were stand-alone units. The commenter indicated

it is unlikely that integrated units can be upgraded in the same way as stand-alone units, 

and used estimated unit costs for integrated units that are twice the cost for a stand-alone 

unit.

 Commenter 0162 believes that 27 mills would actually require upgrades to meet the 94 

percent treatment efficiency requirement, based on the need for a margin of safety for 

compliance at 96 percent removal, instead of the 8 strippers assumed by EPA. Therefore, 

the commenter assumed that mills that only have a stream stripper for condensate control 

and reported a treatment efficiency at or below 96 percent (23 mills) would need 

upgrades. The commenter also assumed that 50 percent of the mills that have dual 

treatment systems (6 mills that use both steam stripping and biological treatment and the 

2 mills that use steam stripping and recycling) that reported treatment efficiencies at or 

below 96 percent would need steam stripper upgrades, for a total of 27 mills that would 

require steam stripper upgrades.

 According to commenter 0162, capital costs for increased aeration were based on the 

average cost for four different mills. In addition to the capital costs outlined above, the 

commenter indicated that each mill would have the following increase in operating costs:

o Additional energy to operate steam strippers at a higher efficiency

o Additional energy to operate more aerators in the wastewater treatment system.

o Additional maintenance for steam strippers to maintain higher treatment efficiencies

o Additional maintenance for aeration and nutrient addition equipment

Commenter 0162 argued that these daily activities would not only add more cost to 

implement the proposed changes, but would also increase emissions from combustion units 

required to generate additional energy in the form of steam and/or electricity. The commenter 

stated that EPA had not accounted for these additional costs or energy impacts in its evaluation.

Commenter 0162 noted that, in considering whether to make the existing MACT 

standards more stringent pursuant to CAA section 112(d)(6), EPA must take into consideration 

the cost of achieving additional emission reductions and non-air-quality health and 
189

environmental impacts and energy requirements. See NRDC v. EPA, 529 F.3d at 1084. 

According to the commenter, EPA had not done so, even with respect to EPA’s greatly 

understated estimate of the expenditures required. The commenter further noted that EO 13563 

directs EPA to assure, to the extent allowed by law, that the benefits of any new rule justify its 

costs and that EPA chose regulatory approaches that minimized the net burden imposed. The 

commenter stated that EPA can and should consider such factors in a technology review under 

CAA section 112(d)(6). According to the commenter, requiring an expenditure of approximately

$38,000 per ton of methanol removed is not at all cost-effective. The commenter also argued that

requiring a diversion of $300 million of capital from other productive investments to address an 

insignificant risk, and also increasing mills’ energy needs for the higher steam stripper 

performance, was not a reasonable action under CAA section 112(d)(6).

In addition to commenter 0162, commenter 0163 also found issue with EPA’s reported 

costs for the 94 percent condensate control option. i.e., $36 million capital cost, an annualized 

investment of $4 million per year for the industry, and a cost effectiveness of $1000 per ton of 

HAP. [76 FR 813452] The commenter believed that the EPA's proposed standard was

inaccurately determined and subject to being changed substantially. Therefore, the commenter 

did not develop a cost estimate for their facilities that may be impacted by a more stringent 

condensate HAP standard. The commenter believed EPA may have understated the potential 

costs because the loss of compliance margin at many mills does not seem to be accounted for in 

the small number of projected facilities (15) that would be affected.

Commenter 0170 believed the proposed lb/ton of methanol destruction requirement for 

process condensates was determined based on an errant methodology, resulting in a limit that 

would necessitate substantial modification or replacement of over 20 of their control systems that 

employ the lb/ton compliance option. The commenter stated that the proposed increase in 

methanol destruction efficiency for condensates (from 92 to 94 percent) would require 

substantial modification or replacement of up to 8 of their control systems in order to maintain an 

adequate margin of compliance. The commenter noted that EPA had estimated fewer system 

changes would be necessary.

Commenter 0167 stated that it was important for the EPA to recognize that additional 

collection would be required and an increase in steam demand would be required for condensate 

strippers when considering the proposed kraft pulping condensate standards. The commenter 

stated that it was not apparent that the EPA had appropriately factored these costs or associated 

environmental impact to produce the necessary steam. The commenter stated that the EPA 

should more fully evaluate these impacts in its cost/benefit analysis.

Response: We disagree with commenter 0162’s claim that EPA did not include any 

information in the preamble to the December 27, 2011 proposed rule or in the docket describing 

how EPA expected mills to comply with the new standards. The preamble indicated that, “The 

three control strategies expected to be used by most mills are recycling the condensates, 

biological treatment and steam stripping,” (76 FR 81345) and noted that biotreatment system and 

stripper upgrades were considered in EPA’s cost analysis (76 FR 81349). In addition, two 

separate memoranda were included in the docket (and referenced in the proposal preamble) to 

address our conclusions at proposal regarding the performance of condensate treatment systems 
190

and cost and environmental impacts of the proposed changes to the condensate standards.170,171

Following proposal, EPA met with this commenter on multiple occasions to discuss the kraft 

condensate standards and the basis for the commenter’s cost estimates.172 The commenter 

supplied additional information based on actual mill experiences and refined their cost estimate 

(that was developed quickly during the 60-day comment period) in response to EPA questions. 

The commenter’s refined estimate was $222 million capital cost and $68 million annualized 

cost.173

Elements of the commenter’s cost and energy impact calculation were included in EPA’s 

independent cost assessment for promulgation. The EPA considered two regulatory options for 

promulgation, 93 and 94 percent HAP removal from condensates. Treatment system

performance levels were completely reanalyzed on a mill-by-mill basis, using data from both the 

pulp and paper Part I ICR Kraft Condensates and Wastewater tables. Mills using the lb/ODTP 

(or ppmw) compliance option were evaluated based on those options instead of using the 

equivalent percent reduction derived for the proposal analysis (also used as the basis for portions 

of the commenter’s cost calculation). We also updated the predominant treatment method for a 

few mills after a closer review of their ICR data and identified mills operating strippers 

integrated with multiple effect evaporators. Our revised analysis took operational and treatment 

system performance variability into account and assigned costs to mills where their reported 

performance level plus a variability cushion did not meet the 93 or 94 percent treatment (or 

equivalent lb/ODTP or ppmw) regulatory option. 

Our analysis revealed that, of the 40 mills using biotreatment as their predominant 

condensate treatment method, 20 mills would be affected under the 93 percent option and 23 

mills would be affected under the 94 percent regulatory option. Either biotreatment system 

upgrade (aeration and nutrient addition) costs or new steam stripper costs were assigned for these 

facilities. A total of 13 and 15 mills were predicted to install a new steam stripper under the 93 

and 94 percent options, respectively. Of 49 mills using strippers, a combination of stripping and 

recycling, or stripping and biotreatment as the predominant form of condensate control, 24 were 

determined to have integrated stripper systems (though not all of these integrated strippers were 

determined to be affected). Stripper upgrade costs were assigned for 28 and 31 stripper systems 

under the 93 and 94 percent regulatory options, respectively. Thus, the overall number of mills 

affected by the 94 percent kraft condensate option increased from 15 mills (at proposal) to 54 

mills in the promulgation analysis.

At proposal, the estimated HAP emission reduction from condensates was attributed to 

all 97 kraft mills because the proposed revisions would reduce the permissible HAP emissions 

even at mills that would not realize any actual emissions reduction because they are already 

 

170 See memorandum from J. Bradfield and K. Spence, EPA, to Docket EPA-HQ-OAR-2007-0544, titled Summary 

of Kraft Condensate Control Technology Review, October 23, 2011, in the docket for the subpart S rulemaking.

171 See memorandum from T. Holloway, K. Hanks, and C. Gooden, RTI, to J. Bradfield and B. Schrock, EPA, titled

Costs and Environmental and Energy Impacts for Subpart S Risk and Technology Review, November 17, 2011, in 

the docket for the subpart S rulemaking.

172 See U.S. EPA documents, titled Meeting notes for the January 12, 2012 meeting with AF&PA; Meeting notes for 

the March 16, 2012 meeting with AF&PA; Meeting notes for the March 28, 2012 meeting with AF&PA; and 

Meeting notes for the May 2, 2012 meeting with AF&PA, in the docket for the subpart S rulemaking.

173 See U.S. EPA document, titled Meeting notes for the May 2, 2012 meeting with AF&PA.
191

performing better than the proposed 94 percent removal. In the promulgation analysis, the HAP, 

VOC, and TRS emissions reduction calculations were revised to apply only for the mills 

anticipated to need upgrades, rather than to reflect the potential emissions reduction for all 97 

kraft mills. This approach more accurately estimates the emission reduction that would actually 

occur as a result of revising the kraft condensate standards.

The promulgation analysis considered the cost impact of revisions to the condensate 

standards on CCA mills. Of the 38 CCA mills, we estimated that the CCA compliance approach 

could potentially be negated by the condensate standard revisions at 11 mills, and that these mills 

would switch from the CCA to use HVLC controls. Switching from CCA to HVLC control was 

estimated to cost $15 million in capital costs and $1.89 million/year in annual costs per mill. We 

also estimated that 34 of the 38 CCA mills would be required to repeat their CCA compliance 

demonstration, at a cost of $130,000 per mill.174

Table 11 summarizes the nationwide cost impacts and emissions reductions estimated for 

the kraft condensate regulatory options considered for promulgation. The estimated nationwide 

HAP emissions reductions range from 989 to 2,300 tpy for the 93 and 94 percent removal 

options. When the costs associated with the repeat CCA demonstration and switching from CCA 

to HVLC are added, the cost effectiveness of the kraft condensates regulatory options becomes 

$75,000/ton and $37,000/ton for the 93 and 94 percent removal options, respectively. Estimated 

costs for promulgation are significantly higher than the proposal estimates because a greater 

number of mills were determined to be affected, considering variability in performance and 

because we have accounted for potential effects on CCA mills. Three small businesses were 

determined to be affected by the kraft condensates regulatory options, one with a cost-to-sales 

ratio of 15 percent (well above the criteria for further consideration of small business impacts 

under the Regulatory Flexibility Act as amended by the Small Business Regulatory Enforcement 

Fairness Act (SBREFA)).

Energy impacts of the regulatory options include electricity use by upgraded aerators in 

biotreatment systems or for new stripper systems, and increased steam use by upgraded or new 

steam strippers. Energy impacts (and associated secondary air emissions) for stripper steam 

generation were not estimated prior to proposal, based on an assumption that upgraded steam 

strippers would likely be more efficient. Energy and secondary air emission impacts for new and 

upgraded steam strippers were included in the promulgation analysis, and were found to be 

significantly higher than the secondary air emissions estimates for electricity usage. Secondary

impacts from additional steam requirements are the consequence of the additional boiler loads 

necessary to generate the steam. These impacts are summarized in Table 12 below and include 

the criteria pollutants PM, CO, NOX, and SO2 and the greenhouse gases (GHGs) carbon dioxide 

(CO2), methane (CH4), and nitrous oxide (N2O). When converted to CO2 equivalents (CO2eq), 

the GHG emissions associated with the 93 and 94 percent removal options would be 1,018,048 

and 1,402,084 tpy CO2eq, respectively.

 

174 See memorandum from T. Holloway, K. Hanks, and C. Gooden, RTI, to J. Bradfield and B. Schrock, EPA, titled 

Costs, Environmental, and Energy Impacts for the Promulgated Subpart S Risk and Technology Review, May 15, 

2012, in the docket for the subpart S rulemaking.
192

Table 11. Summary of Nationwide Costs and Cost Effectiveness for the Kraft Condensate Regulatory Options

Subpart S regulatory 

option

Costs Emissions reductions, tpy

Cost effectiveness, 

$/ton HAP

No. of mills 

affected

Capital, 

$million

Annualized, 

$million/yr HAP/ VOCa TRS

92% → 93% $227 $52.6 989 336 $53,175 48

92% → 94% $254 $63.3 2,300 702 $27,508 54

Repeat CCA 

Demonstration

$4.42 $0.996 -- -- -- 34

Switching from CCA 

to HVLC

$165 $20.8 Not estimatedb Not estimatedb-- 11

Total costs for 

condensate options:

 93%

 94%

$396

$423

$74.4

$85.1

989

2,300

336

702

$75,000

$37,000

a. HAP emissions are approximately 99% methanol and 1% acetaldehyde. VOC emissions reductions would be essentially equivalent to HAP emissions 

reductions.

b. Because the CCA compliance approach, by design, must achieve greater HAP emission reduction than the HVLC compliance approach would have achieved, 

it can be expected that HAP emissions may increase as a result of switching to HVLC if the mill were to abandon the CCA technology generating emissions 

credits.

Table 12. Summary of Estimated Nationwide Environmental and Energy Impacts 

Subpart S 

regulatory 

option

Energy impacts, 

MMBtu/yr Secondary emissions, tpy No. of mills 

Electricity Steam PM affected a CO NOX SO2 CO2 CH4 N2O

92% → 93% 99,419 660 430 2,082 1,443 659 1,004,258 65 40 48

92% → 94% 113,685 910 593 2,870 1,986 901 1,383,081 89 55 54

a. Filterable (front-half) PM.
193

The revised kraft condensate standards were considered under the technology review 

authority of CAA section 112(d)(6), and not under section 112(f)(2). The EPA must take into 

consideration the cost of achieving additional emission reductions and non-air-quality health and 

environmental impacts and energy requirements when setting standards pursuant to CAA section 

112(d)(6). The EPA no longer considers the proposed 94 percent revision to the kraft condensate 

standards to be cost-effective in terms of the amount of HAP reduced. Nor does EPA consider 

the 93 percent regulatory option considered for promulgation to be cost-effective. The 

nationwide energy impacts and secondary air emissions associated with regulatory options are 

substantial compared to the HAP emissions reduction, primarily due to the power boiler 

emissions associated with the increased steam demand needed for new and upgraded steam 

stripper systems. Additionally one affected small business was estimated to experience a cost-tosales ratio of 15 percent. For all of these reasons, EPA decided not to finalize the proposed 

amendments to the kraft condensate standards (based on the 94 percent reduction option) or to 

promulgate a slightly less stringent standard than proposed (based on the 93 percent reduction 

option).

131. Comment: Cost Impact to Comply with Proposed Lb/Ton Removal Limits. Commenter 

0162 argued that EPA underestimated the cost impact to comply with the lb/ton of pulp removal 

limits in the proposed rule. For the purposes of this estimate, the commenter assumed that the 

treatment standards were those published in the December 27, 2011 proposal, and that mills 

wishing to use the compliance option based on demonstrating the mass of HAP removed per ton 

of pulp produced would have to demonstrate the 12.8/8.3 lb/ODTP (bleached/unbleached) 

removal rates in the proposal, rather than the nominal increase in removal rates associated with 

increasing condensate treatment efficiency from 92 to 94 percent, described above. The 

commenter estimated that total capital costs would be approximately $834 million, and 

annualized capital costs plus operation and maintenance costs would be over $200 million, or 50 

times greater than EPA estimated.

Commenter 0162 stated that the proposed lb/ODTP standard for condensate treatment 

would require additional collection of condensates from non-CCA mills, as explained above, 

based on the investments described above, plus additional collection of condensates from CCA 

mills. The commenter estimated that currently 38 mills use the CCA in §63.447 for MACT I 

Phase 2. Of those 38 mills, the commenter estimated that 34 demonstrated compliance through 

collection of additional condensates, which the commenter said would need to be increased. 

According to the commenter, if those mills were required to demonstrate an increased removal of 

HAPs in condensate of approximately 25 percent, as EPA has proposed, then, based on their 

current configurations, the mills using the CCA likely could not continue to rely on the CCA to 

comply with the new lb/ODTP removal requirements. Therefore, the commenter assumed that all 

mills currently using the CCA would need to collect HVLC gases and route them to a single 

control device. The commenter estimated this capital cost at $15 million per mill. The 

commenter noted that this cost assumed the 4 percent venting provision for HVLC systems 

remained in place; otherwise the commenter indicated a back-up control device (at a minimum) 

would be needed, at substantial additional cost.

Commenter 0162 argued that imposing a cost of approximately $200 million per year to 

achieve only an incremental reduction in emissions of mostly methanol would not be costeffective. The commenter also argued that requiring a diversion of $834 million in capital from 
194

other productive investments to address an insignificant risk, and also increasing mills’ energy

needs for the higher steam stripper performance, was not a reasonable action under section 

112(d)(6).

Response: As stated previously, EPA did not intend to propose an increase in the 

condensate collection requirements. Therefore, the commenter’s cost estimates included here 

(and the revised costs discussed on May 2, 2012) are not relevant.175 Costs for 11 mills (i.e.,

costs for switching from CCA to HVLC compliance) where the CCA option may be negated due 

to the more stringent condensate removal standard (e.g., 93 or 94 percent removal) were included 

in the revised cost analysis for promulgation.

132. Comment: Two other commenters (0212 and 0170) believed that EPA had

underestimated the cost to implement the proposed rule changes. Both commenters referred to 

the information provided by commenter 0162 on the subject to support their argument.

Commenter 0170 further argued that EPA’s estimate at proposal of a $36 million industry-wide 

investment to upgrade condensate control system efficiencies was a significant underestimation. 

According to the commenter, the AF&PA’s rough estimate, based on the incomplete 

understanding left by the proposal, indicates that the rule, which EPA determined would have a 

minor economic impact, could cost the industry as much as $2.4 billion dollars, an amount 

exceeding the costs of the air process portion of the original Cluster Rule and the combustion 

source rule (subparts S and MM). Even with this type of investment, it was not clear to the 

commenter whether the industry or their company could comply with all of the changes to the 

proposed rule because of cost and safety considerations. Given EPA’s conclusion in the 

accompanying residual risk review that the industry presented acceptable risks, the commenter 

asserted that the prospect of billions of dollars of additional investment was unwarranted because 

it would not materially increase public protection.

Response: We interpret this comment as referring to costs associated with: (1) the 

proposed kraft condensate limits, and (2) our request for comment on the excess emissions 

allowances. Discussion of costs for the kraft condensate regulatory options is provided in the 

responses above. The EPA has decided not to revise the kraft condensate standards. The EPA has 

deferred action on the excess emissions allowances and will explore the costs associated with 

removal of the excess emission allowances in analyses supporting proposal of a future 

regulation.

133. Comment: Commenter 0172 argued that EPA is obligated to consider the cost of 

modifications during the RTR process. The cost of complying with the standards without the 

1 percent, 4 percent, and 10 percent allowances must be considered. The commenter’s initial 

assessment of the cost of complying with these standards at their facilities alone was between 

$100 and $180 million, primarily in the form of process modifications, alternative condensate 

and vent gas collection systems, backup condensate treatment systems and backup vent gas 

incineration systems. 

Response: The EPA has deferred action and will further investigate the removal of the 

excess emission allowances in a future regulation.

 

175 See U.S. EPA document, titled Meeting notes for the May 2, 2012 meeting with AF&PA.
195

12. Miscellaneous Comments

12.1 Commenter Endorsements

134. Comment: Multiple commenters (0164, 0165, 0167, 0170, 0172, 0174, 0193, 0195, 

0207, and 0212) endorsed the comments made by the AF&PA on the pulp and paper proposal. 

Five comments (0163, 0167, 0170, 0172, and 0212) also specifically endorsed the comments 

made by NCASI. Commenters 0170 and 0172 noted that they had also participated in the 

creation and/or review of the comments made by the AF&PA and NCASI.

Commenter 0164 specifically expressed support for the comments on the proposed SSM 

provisions that were submitted by the AF&PA. Rather than repeat those comments here, the 

commenter (0164) incorporated AF&PA’s comments on the proposed SSM provisions into their

comments by reference. Commenter 0163 specifically endorsed and submitted a copy (0163.2) 

of the February 18, 2012 interim comments provided by NCASI on RTR condensate treatment 

requirements.

Response: We acknowledge the commenters’ collective support for the AF&PA and 

NCASI comments.

135. Comment: Commenter 0174 supported the article by the NCSAB entitled “Risk 

Assessment for Arsenic and Inorganic Arsenic Compounds” and provided a copy of the article.

Response: We acknowledge the commenter’s reference to the article.

136. Comment: In support of their mills-specific NEI updates, several commenters (0154, 

0187 (0187.3), 0190, and 0198) provided copies of the February 24, 2012 NCASI memorandum 

entitled “Hexachloroethane Emissions from Brownstock Washers and Bleach Plant Sources.”

Response: We acknowledge the commenters’ support for NCASI’s HCE memo, which 

was summarized as Attachment 3 to comment 0162.

137. Comment: Commenter 0214/0225 endorsed the comments submitted by Earthjustice and 

coalition.

Response: We acknowledge the commenter’s support for the Earthjustice (and coalition) 

comments.

12.2 Other Comments

138. Comment: Commenter 0170 suggested the EPA did not interpret mill ICR data 

correctly. The commenter stated that, without the familiarity with the process equipment and 

control systems that only company representatives could have, the EPA incorrectly interpreted 

the data. The commenter stated that they had suggested discussion with EPA, but they were not

consulted in developing the proposal. The commenter believed substantial additional 

communication with EPA is needed to help interpret the data, the cost impact of the proposed 

provisions, the unrecognized adverse impacts that would result if the pulp and paper NESHAP
196

rule is promulgated (as proposed), and reasonable means for revising the standards. The 

commenter again offered to communicate with the Agency to whatever extent is needed to share 

understanding of these important matters.

Response: We appreciate the commenter’s willingness to describe pulp and paper mill 

operations and to assist the Agency with future interpretations of the ICR data.

139. Comment: Commenter 0214/0214.1 provided 2009 reported air toxics releases for 

Nippon Paper Industries in Port Angeles, WA as additional input on typical reported emissions 

under present laws. The commenter noted that Nippon is regulated by Olympic Region Clean Air 

Agency.

Response: We thank the commenter for providing the inventory information for Nippon 

Paper. We compared the inventories with the NEI inventory used for our residual risk assessment 

and found that the HAP emissions in the inventories supplied by the commenter compare 

favorably with the NEI data. The NEI data set used for risk modeling included additional HAPs 

and in some cases a higher tonnage of selected HAPs.

140. Comment: Commenter 0225 provided a 2009 emissions inventory for Port Townsend 

Paper (see comment attachment 0225.1). The commenter noted that the TRI and the Regional 

Airs’ Point Source Emissions Inventory are good tools for compiling and understanding 

emissions data, but data for many reported pollutants or point sources are elusive. The 

commenter pointed out that the inventories do not list several NESHAP pollutants for PTPC. 

Response: We thank the commenter for providing the two inventories for PTPC. We 

compared the commenter’s inventories with the NEI inventory used for our pre-proposal residual 

risk assessment and the NEI inventory that includes post-proposal NEI revisions from the mill.

We found that the HAP emissions in the inventories supplied by the commenter compare 

favorably with the pre- and post-proposal NEI data. The pre- and post-proposal NEI data sets

include additional HAPs not listed on the inventories supplied by the commenter. The 

commenter should also note that the TRI does not include emissions data for pollutants emitted 

below specified threshold levels. 

141. Comment: Commenter 0214 attached a set of five documents (comment attachments 

0214.1 through 0214.6) that the commenter believed illustrate a disconnect between enacted laws 

and how their actual enforcement plays out, or other areas for attention within the regulatory

system. The commenter’s Attachment B1 is a summary of State laws the commenter contended

that the Washington Department of Ecology has refused to enforce. The commenter’s 

Attachment B2 provides examples of misinformation to the public. The commenter’s 

Attachments B3, B4, and B5 are 2008 letters calling for Washington Department of Ecology

Industrial Section oversight of Port Townsend Paper. Commenter 0214 also attached a photo 

(comment attachment 0214.7) illustrating how the tops of Port Townsend Paper’s stack point 

directly at the local hospital. Commenter 0214 also attached two documents in electronic form:

(1) a petition regarding Port Townsend Paper (comment attachment 0214.8), and (2) complaint 

summary logs (comment attachment 0214.9). The commenter stated that the call logs that are on 

file with the Washington Department of Ecology relate accounts of heart palpitations, migraines, 

respiratory distress, burning eyes and skin, headaches, sinus and breathing problems, coughing, 
197

nausea and vomiting, sleep apnea, and other sleep disturbances, along with daily inconveniences, 

such as having to change plans to avoid being in certain parts of town when the plume arrives. 

The commenter stated that it is notable that midway in the 6-month spreadsheet, Port Townsend 

Paper stopped recording the reasons for the calls after having already ceased to log what they did 

about it.

Response: We acknowledge this comment and the concerns of the commenter, but note 

that comments pertaining to enforcement or compliance issues at specific facilities are outside 

the scope of this rulemaking. We should note that the final rule requires repeat emission testing 

for kraft pulping processes and steam strippers and removes the SSM exemption–changes which 

should reduce the potential for the emissions episodes of concern to the commenter.

142. Comment: Commenter 0225 stated that the current environmental laws discourage 

upgrading until absolutely forced to, and much of the equipment at Port Townsend Paper is 

approaching the end of its design life. The commenter asserted that it is easier for the mill to 

begin a 25 megawatt (MW) power generating expansion than to upgrade existing technologies. 

The commenter encouraged MACT rules that would require the mills to install modern 

equipment, instead of relying on the best available retrofit technology (BART) options. 

Commenter 0225 believed that tighter rules are necessary, but would be meaningless if 

not enforced. Because PTPC is a kraft pulp mill in the state of Washington, it is regulated by the

Washington Department of Ecology's Industrial Section, rather than by the regional air quality

authority, in contrast to other pulp mills. The commenter stated that the Department of Ecology

coached the facility on ways to avoid PSD, which also allowed them to avoid MACT rules that 

otherwise would have been triggered by PSD. 

Response: We acknowledge this comment and the concerns of the commenter, but note 

that comments pertaining to enforcement or compliance issues at specific facilities and issues 

pertaining to PSD are outside the scope of this rulemaking. It is expected that there would be 

some discussion between the permitting authority and an affected source’s responsibilities in 

regard to permitting requirements.

143. Comment: Commenter 0225 expressed concern that CO2 emissions data are not 

collected, as it is under the supervision of the Washington Department of Ecology Industrial 

Section rather than the regional air quality authority. Exemptions such as this should not be 

allowed. The commenter also noted that the 25 MW expansion project would lead to greatly 

increased CO2 emissions, a contributing factor in climate change. The commenter estimated that 

the mill emits around 300 million pounds of CO2 per year. The commenter noted that the 

expansion project may "more than double" the CO2 emissions to 600 million pounds, yet that 

was not taken into account when approving the project--even though CO2 emissions are a major 

issue.

Response: The reporting and collection of CO2 emission data are outside the scope of the

subpart S pulp and paper NESHAP. The current review of the subpart S NESHAP addresses 

HAP emissions from subpart S emission sources, which does not include recovery furnaces or 

industrial boilers. 
198

However, we note that biogenic and non-biogenic CO2 emissions (and other GHGs) from 

the Port Townsend facility’s recovery furnace and industrial boilers are required to be reported to 

EPA annually under EPA’s Mandatory Greenhouse Gas Reporting rule (40 CFR part 98 subparts 

C and AA). Additionally, EPA is conducting a detailed examination of the science associated 

with biogenic CO2 emissions from stationary sources, and this work is undergoing SAB review.

144. Comment: Commenter 0218 attached many of the documents referenced in their 

comment (e.g., toxicity studies, background information). These documents are included as six 

file sets, items 0219.1 - 0224.18 in the docket.

Response: We acknowledge the referenced documents provided by the commenter.
A-1

Appendix A. Mills Providing NEI Revisions

NEI Code

Docket 

ID for 

NEI 

Revision Nature of the NEI Revision

NEI13363 0147 Reduced acetaldehyde, formaldehyde from WWT

NEI54400 0151 -Reduced acetaldehyde, methanol from paper machine

-Changed latitudes/longitudes for pulp operation, paper machines, hot water accumulator drain

NEI45206 0154 Deleted HCE from bleach plant, pulp storage

NEI26581 0155 -Deleted HCE from bleach plant and 2-methylnaphthalene from SDTs

-Changed pollutant from hexachlorobenzene to hexachlorocyclopentadiene for SDTs

NEI42338 0158 Reduced acetaldehyde, chloroform, formaldehyde, 13 other HAPs from WWT

NEI6273 0159 -Increased acetaldehyde from paper machines, pulp dryer

-Reduced acetaldehyde from WWT

-Deleted records for non-operational boiler

-Deleted carbon tetrachloride from paper machines, pulp dryer

-Changed latitudes/longitudes for groundwood operations, NDCE recovery furnace, and boiler

-Recommended change to receptor location

NEI11338 0166 -Reduced fugitive area of WWT

-Reduced acetaldehyde from BLO unit and nickel from lime kiln

-Deleted naphthalene from BLO unit

-Changed latitudes/longitudes for WWT, BLO unit

-Split up BLO unit emissions

-Change release point type for BLO unit from vertical to vertical with rain cap

NEI42482 0169 -Reduced formaldehyde from EU BLT12 (Bleach Tower 2)

-Replaced formaldehyde from EU BLT22 (Bleach Tower 2) with much lower estimate for EU 

BLT14 (Bleach Tower 4)

NEIWI4050324 0169 -Added vinyl acetate to dryformer

-Reduced acetaldehyde from dryformer

NEI12980 0173 -Reduced stack velocity and increased stack diameter for Bleach Tower 1 

-Increased stack velocity and reduced stack diameter for Bleach Tower 2

NEI40282 0174 -Reduced acetaldehyde, formaldehyde from paper machines

-Reduced 1,2-dichloroethane from brownstock washing

-Deleted 1,2-dichloroethane from oxygen delignification, lime kiln, boiler

NEI40686 0175 -Deleted HCE from bleach plant

-Deleted acetaldehyde, chloroform, formaldehyde, methanol, 18 other HAPs from causticizing

-Deleted acetaldehyde, acrolein, chloroform, formaldehyde, methanol, naphthalene, 28 other 

HAPs from SDT

-Changed latitude/longitude for WWT

-Recommended change to receptor location

NEI18652 0176 Reduced arsenic from boiler

NEI32869A 0177 -Reduced acetaldehyde, formaldehyde from paper machines, pulp dryer

-Deleted HCE from bleach plant, pulp storage

NEI18373 0178 Reduced acetaldehyde from WWT

NEI40738 0179 -Reduced nickel from paper machine

-Deleted acetaldehyde, methanol from papermaking fugitives

-Recommended change to receptor location

NEI42695 0180 -Deleted antimony, beryllium, and cadmium from digester

-Changed latitudes/longitudes for digester, decker, and ClO2 generator

-Recommended change to receptor location

NEI34066 0181/0191 -Increased fugitive area for WWT

-Deleted HCE from bleach plant

-Changed latitude/longitude for WWT
A-2

NEI Code

Docket 

ID for 

NEI 

Revision Nature of the NEI Revision

NEI46739,

NEI42963, & 

NEIWI7720116

0182 NEI46739:

-Increased acetaldehyde, methanol, benzene, MIBK, toluene from causticizing miscellaneous

-Reduced chloroform, formaldehyde, 7 other HAPs from causticizing miscellaneous

-Deleted carbon tetrachloride and 1,1,2-trichloroethane from causticizing miscellaneous

NEIWI7720116:

-Reduced acetaldehyde, chloroform, formaldehyde, methanol, catechol, cresol, ethylene glycol, 

phenol from WWT

-Recommended change to receptor location

NEI12407 0183 Deleted records for NCG incinerator (includes metals, formaldehyde, naphthalene)

NEI6261 0184 Reduced acetaldehyde, naphthalene, carbon disulfide, propionaldehyde from WWT

NEI41599 0185 Added bis(2-ethylhexyl) phthalete, dibutyl phthalate, toluene to WWTP1/2; formaldehyde to 

WWTP1; cresol, phenol to WWTP2

-Reduced acetaldehyde, methanol from WWTP1/2; formaldehyde from WWTP2

-Deleted HCE from bleach plant

-Deleted acetaldehyde, chloroform, formaldehyde, methanol, naphthalene, 21 other HAPs from 

causticizing

-Deleted acetaldehyde, acrolein, chloroform, formaldehyde, methanol, naphthalene, 28 other 

HAPs from SDT

NEI18338 0186 -Added ASB (includes acetaldehyde, carbon disulfide, chloroform, formaldehyde, methanol, 

naphthalene)

-Reduced acetaldehyde, chloroform, formaldehyde, naphthalene from primary clarifier

-Deleted methanol, HCE, and 17 other HAPs from primary clarifier

NEI18658 0187 -Reduced naphthalene, 10 other HAPs from bleach plant

-Deleted HCE from brownstock washing, bleach plant, knotters, BLO unit

NEI46599 0188 -Reduced acetaldehyde, chloroform, formaldehyde, methanol, naphthalene, 27 other HAPs 

from brownstock washing, black liquor storage tanks

-Increased stack temperature and velocity/flow for brownstock washing, SOG, pulp storage, 

oxygen delignification, black liquor tanks, causticizing, bleach plant, knotter, secondary fiber 

pulping when changed release point type

-Changed release point type for brownstock washing and black liquor storage tanks from 

fugitive to vertical with rain cap

-Recommended change to receptor location

NEI42211 0189 Changed latitudes/longitudes and fugitive angles for OCC plant and paper machine

NEI8186 0190 -Increased methylene chloride from LVHC

-Reduced acetaldehyde, formaldehyde, chloroform, methanol from LVHC

-Deleted records for causticizing miscellaneous, lime slaker (includes acetaldehyde, 

chloroform, naphthalene)

NEI8560 0190 -Deleted records for causticizing miscellaneous, lime slaker (includes acetaldehyde, 

chloroform, naphthalene)

-Changed latitude/longitude and fugitive angle for WWT

-Recommended change to receptor location

NEI8619 0190 Deleted records for causticizing miscellaneous, lime slaker (includes acetaldehyde, chloroform, 

methanol, naphthalene)

NEI11251 0190 -Replaced undifferentiated records for paper machine with new records for paper machine 

wet/dry end

-Increased stack height for paper machines

-Increased fugitive area for WWT

-Deleted records for causticizing miscellaneous, lime slakers (includes acetaldehyde, 

chloroform, methanol, naphthalene)

-Changed latitude/longitude for WWT

NEI18335 0190 -Deleted records for causticizing miscellaneous, lime slaker (includes acetaldehyde, 

chloroform, methanol, naphthalene)

-Deleted HCE from bleach plant

NEI18357 0190 Deleted HCE from bleach plants
A-3

NEI Code

Docket 

ID for 

NEI 

Revision Nature of the NEI Revision

NEI26309 0190 -Increased fugitive area for WWT (ASB)

-Deleted HCE from bleach plant

-Changed latitudes/longitudes for WWT (ASB, up/downstream ditches)

-Changed fugitive angle for WWT (upstream ditch)

NEI26495 0190 Recommended change to receptor location

NEI26514 0190 -Reduced fugitive area of WWTP6

-Increased fugitive area for WWTP1-4

-Deleted records for causticizing miscellaneous, lime slaker (includes acetaldehyde, 

chloroform, methanol, naphthalene)

-Deleted HCE from bleach plant

-Changed latitudes/longitudes for WWTP1-4,6

-Changed fugitive angle for WWTP1,6

NEI33013 0190 Deleted records for causticizing miscellaneous, lime slaker (includes acetaldehyde, chloroform, 

methanol, naphthalene)

NEI33025 or 

NEW71411

0190 Deleted records for causticizing miscellaneous, lime slaker (includes acetaldehyde, chloroform, 

methanol, naphthalene)

NEI34070 0190 -Replaced undifferentiated records for paper machine with new records for paper machine wet 

and dry end

-Increased stack height and stack velocity/flow for paper machine when replaced paper 

machine records with separate wet/dry end records

-Deleted records for causticizing miscellaneous, lime slaker (includes acetaldehyde, 

chloroform, methanol, naphthalene, 15 other HAPs)

-Changed latitude/longitude for paper machine when replaced paper machine records with 

separate wet/dry end records

NEI35908 0190 -Deleted records for causticizing miscellaneous, lime slaker, green liquor processing (includes 

acetaldehyde, chloroform, methanol, naphthalene)

-Deleted HCE from bleach plant

NEI40247 0190/0227 -Added phenol to digester chip bin

-Reduced acetaldehyde, formaldehyde, chloroform, methanol, and 16 other HAPs from digester 

chip bin

-Deleted records for causticizing miscellaneous, lime slaker (includes acetaldehyde, 

chloroform, naphthalene, methanol)

-Deleted HCE from bleach plant

NEI41314 0190 -Deleted records for causticizing miscellaneous, lime slaker (includes acetaldehyde, 

chloroform, methanol, naphthalene)

-Deleted HCE from bleach plants

-Deleted naphthalene from causticizing miscellaneous, LVHC, NCG incinerator, BLO unit

-Deleted 8 HAPs from WWT

-Changed latitude/longitude for WWT

-Recommended change to receptor location

NEI41628 0190 -Deleted records for causticizing miscellaneous, lime slaker (includes acetaldehyde, 

chloroform, methanol, naphthalene)

-Deleted HCE from bleach plant

NEI45182 0190/0227 -Added phenol to digester chip bin

-Reduced acetaldehyde, formaldehyde, chloroform, methanol, and 16 other HAPs from digester 

chip bin and LVHC

-Changed latitude/longitude for WWT

NEI46760 0190 -Deleted records for causticizing miscellaneous, lime slaker (includes acetaldehyde, 

chloroform, methanol, naphthalene)

-Deleted HCE from bleach plants

NEI33883 0192 -Reduced acetaldehyde, formaldehyde, naphthalene from WWT

-Changed fugitive angle for WWT

-Recommended change to receptor location

NEI47104 0193 -Increased stack height, temperature, and velocity/flow for paper machine when changed 

release point type

-Changed release point type for paper machines from fugitive to vertical point source
A-4

NEI Code

Docket 

ID for 

NEI 

Revision Nature of the NEI Revision

NEI54342 0194 -Changed release point type for causticizing, pulp storage, black liquor tanks, brownstock 

washing, decker from fugitive to stack

-Reduced stack height for some black liquor storage tanks

-Increased fugitive release height and reduced fugitive area for other black liquor storage tanks

-Increased stack height for causticizing (lime mud filter, lime slaker), pulp storage, decker

-Increased stack temperature, diameter, and velocity/flow for causticizing, pulp storage, black 

liquor tanks, brownstock washing, decker when changed release point type

NEI41552 0195 Recommended change to receptor location

NEI18334 0197 -Reduced stack height for screens, lime mud filter, green liquor processing when changed their 

release point type from fugitive to stack

-Increased formaldehyde, Cr+6, 2 other HAPs from recovery furnace

-Increased acetaldehyde, methanol, formaldehyde, metals, naphthalene, 5 other HAPs from 

SDT

-Reduced velocity of NCG incineration

-Added metals, chloroform, POM, toluene, hexane to recovery furnace

-Added Cr+6, POM, 6 other HAPs to SDT

-Increased stack height for SDT and multiple subpart S units (50) when changed their release 

point type from fugitive to stack

-Reduced naphthalene from WWT

-Reduced acetaldehyde, carbon tetrachloride, chloroform, formaldehyde, methanol, 

naphthalene, phenol, other HAPs from decker

-Reduced acetaldehyde metals, methanol, naphthalene, 7 other HAPs from recovery furnace

-Reduced chloroform, metals, 18 other HAPs from SDT

-Increased stack temperature for SDT and multiple subpart S units (46) when changed their 

release point type from fugitive to stack

-Increased stack velocity/flow for SDT and multiple subpart S units (55) (56 if include just 

stack flow of NCG incineration) when changed release point type

-Deleted records for bleach plant, knotter, brownstock washing, digester, screens (accounted 

for elsewhere) and decker, causticizing miscellaneous, lime mud washer (no longer in service) 

(includes acetaldehyde, chloroform, formaldehyde, methanol, naphthalene)

-Deleted HCE from bleach plants

-Deleted HCl from recovery furnace

-Changed release point type for SDT and multiple subpart S units (56) from fugitive to stack

NEI46817 0198 -Reduced nickel from boiler

-Deleted HCE from bleach plants

NEI34030 0199 -Reduced stack height for mechanical pulping

-Reduced stack velocity, flow for mechanical pulping

-Replaced undifferentiated records for paper machine with new records for paper machine 

wet/dry end

-Increased stack temperature for mechanical pulping

-Increased stack velocity/flow for boilers

-Changed latitude/longitude for paper machine when replaced paper machine records with 

separate wet/dry end records

-Changed latitudes/longitudes for boilers

NEI26504 0200 Deleted records for recovery furnaces, SDTs (being replaced with new units, emissions data for 

which will not be ready until September 2012)

NEI7181 0201 Deleted HCE from bleach plant, LVHC, HVLC, recovery furnace, SDT, lime kiln

NEI18660 0202 -Reduced acetaldehyde from oxygen delignification

-Deleted HCE from bleach plant

-Deleted formaldehyde from pulp dryer

-Recommended change to receptor location

NEI8265 0203 -Deleted HCE from bleach plant

-Deleted toluene-2,4-diamine from black liquor storage tanks
A-5

NEI Code

Docket 

ID for 

NEI 

Revision Nature of the NEI Revision

NEI47074 0204 - Replaced fugitive records for causticizing, paper machines with stack records for green liquor 

processing, paper machines

-Increased stack height, temperature, diameter, and velocity/flow for paper machines when 

replaced fugitive paper machine records with stack records

- Changed release point type for causticizing, paper machines from fugitive to stack

-Changed latitudes/longitudes for paper machines

-Changed brownstock washing to paper machine (SCC changed)

NEIME0250002 0205 -Reduced stack temperature of boilers

-Replaced fugitive records for pressurized groundwood emission units with stack records (with 

lower emissions for acetaldehyde, formaldehyde, methanol, phenol, napthalene, etc.)

-Increased stack height, temperature, velocity/flow of pressurized groundwood emission units 

when replaced them with stack equivalents

-Increased stack height, diameter, velocity/flow of boilers

-Changed release point type for pressurized groundwood emission units from fugitive to stack

-Changed latitudes/longitudes for pressurized groundwood emission units and boilers

-Recommended change to receptor location

NEI8178 0206 -Increased acetaldehyde, chloroform, methanol, toluene, biphenyl from decker

-Replaced unconsolidated records for paper machines with new (consolidated) records

-Added 10 HAPs to bleach plant, paper machines, decker

-Reduced acetaldehyde, formaldehyde, chloroform, methanol, toluene, benzene, MIBK, carbon 

disulfide from WWT, decker

-Deleted naphthalene from WWT and acrylonitrile from paper machines

-Changed maximum hourly emissions

NEI40600 0209 -Replaced fugitive records for paper machines with stack records

-Reduced acetaldehyde, formaldehyde, chloroform, methanol, 19 other HAPs from black liquor 

storage tanks

NEI8196 0210 -Increased stack heights for lime mud filter, lime slaker

-Reduced acetaldehyde, naphthalene from WWT

-Increased stack temperature and velocity/flow for lime mud filter when changed its release 

point type

-Deleted toluene-2,4-diamine from black liquor storage tanks

-Changed release point type for lime mud filter from fugitive to stack

-Changed latitude/longitude for lime mud filter

-Increased stack diameter for lime slaker

NEI40554 0211 -Increased stack temperature, diameter, and velocity/flow for HD/LD pulp storage when 

changed release point type

-Changed release point type for HD/LD pulp storage from fugitive to horizontal point source

NEI33981 0213 -Reduced stack temperature of boilers

-Increased stack height, diameter, and velocity/flow for boilers

-Deleted duplicate HAP data from boilers (includes acetaldehyde, formaldehyde, naphthalene, 

metals, and 22 other HAPs)

-Changed latitudes/longitudes for boilers

NEI11172 0217 -Reduced fugitive area of WWT

-Reduced acetaldehyde from WWT

-Changed latitude/longitude and fugitive angle for WWT

-Changed fugitive angle for WWT

NEI7104 0226 -Added metals to boiler

-Increased stack height for bleach plant, deckers

-Reduced metals from boiler

-Deleted methylene chloride and carbon disulfide from lime kiln

NEI47091 0230 -Increased acetaldehyde, formaldehyde, methanol, naphthalene, metals, 29 other HAPs from 

recovery furnace, SDT, lime kiln

-Increased metals, HCl from boilers

-Reduced metals, chloroform, 11 other HAPs from recovery furnace, SDT, lime kiln

-Reduced metals from boilers

-Deleted HCE from bleach plant, brownstock washing

-Changed maximum hourly emissions for recovery furnace, SDT, lime kiln, boilers
A-6

NEI Code

Docket 

ID for 

NEI 

Revision Nature of the NEI Revision

NEI7933 0232 -Increased stack diameter and velocity/flow for green liquor processing when changed release 

point type

-Deleted chloroform and 10 other chlorinated HAPs from digester, pulp storage, LVHC, 

brownstock washing, secondary fiber pulping

-Deleted o-cresol from brownstock washing, green liquor processes

-Deleted o-xylene from pulp storage

-Deleted biphenyl from paper machine

-Changed release point type for green liquor processing

-Changed latitude/longitude for pulp storage

NEI8261 0232 -Replaced records for PB5 and PB7 with updated records (that increase emissions)

-Deleted 11 chlorinated HAPs from tall oil, pulp storage, black liquor tanks, brownstock 

washing, LVHC, screens, secondary fiber pulping, paper machines

-Deleted biphenyl from secondary fiber pulping, paper machine

-Deleted o-cresol from brownstock washing

NEI8278 0232 -Increased stack diameter and velocity/flow for green liquor processing, black liquor tanks, 

pulp storage when changed release point type

-Deleted HCE from bleach plant

-Deleted o-cresol from bleach plant, green liquor processing, brownstock washing, recovery 

furnace

-Changed release point type for green liquor processing, black liquor tanks, pulp storage

-Changed pollutant code for m,p-cresol

NEI11461 0232 -Replaced records for secondary clarifier and boiler with new records

-Deleted biphenyl from secondary fiber pulping and paper machines

-Changed latitudes/longitudes for primary/secondary clarifiers

-Changed fugitive angle for secondary clarifier

NEI11610 0232 -Replaced records for paper machine with new records for all 12 vents on machine

-Increased stack height, temperature, diameter, and velocity/flow for secondary fiber pulping, 

paper machines, space heaters when changed release point type

-Changed release point type for secondary fiber pulping, paper machines, space heaters

NEI18347 0232 -Reduced fugitive area for primary/secondary clarifier

-Replaced records for primary/secondary clarifier, ASB with new records (with revised fugitive 

angle)

-Increased fugitive area for ASB

-Deleted 9 chlorinated HAPs from HVLC

-Deleted biphenyl from secondary fiber pulping

-Deleted 11 chlorinated HAPs from SDT

NEI26304 0232 -Added records for primary clarifier, ASB

-Deleted o-xylene, 4 chlorinated HAPs from pulp storage

-Deleted biphenyl, methylene chloride from paper machine and secondary fiber pulping

NEI33023 0232 -Reduced fugitive area of primary clarifier, WWTP

-Increased metals, PCB emissions from boilers

-Added Cr+3, methanol, POM, PCBs, 11 other HAPs to boilers

-Reduced metals emissions from boilers

-Increased stack temperature, diameter, velocity/flow for stock chests when changed release 

point type

-Deleted chloroform, 11 other chlorinated HAPs from brownstock washing, paper machine, 

secondary fiber pulping, NCG incinerator, pulp storage, tall oil

-Deleted biphenyl from paper machine

-Deleted o-cresol from green liquor processing

-Deleted Be, Se from boiler

-Changed release point type for stock chests

-Reduced fugitive angle for primary clarifier

-Increased fugitive angle for WWTP
A-7

NEI Code

Docket 

ID for 

NEI 

Revision Nature of the NEI Revision

NEI42254 0232 -Replaced records for boilers with new records

-Added total xylenes to screens, lime kiln

-Increased stack height and temperature for evaporator/concentrator when changed release 

point type

-Increased stack diameter and velocity/flow for evaporator/concentrator, green liquor 

processing when changed release point type

-Deleted biphenyl from paper machines

-Deleted o-cresol from bleach plant, green liquor processing, recovery furnace

-Deleted o-xylene from tall oil, screens, lime kiln, recovery furnace

-Changed release point type for evaporator/concentrator, green liquor processing

NEI42317 0232 -Increased stack diameter and velocity/flow for green/white liquor processing, pulp storage, 

black liquor tanks, lime slaker when changed release point type

-Deleted 12 chlorinated HAPs from digester, brownstock washing, tall oil, pulp storage, 

evaporator/concentrator

-Deleted o-xylene from pulp storage

-Changed release point type for green/white liquor processing, pulp storage, black liquor tanks, 

lime slaker from fugitive to stack

-Changed SCC from 30700122 (causticizing miscellaneous) to 30700132 (green liquor 

processing)

NEI45474 0232 -Deleted records for ClO2 mixer (includes acetaldehyde, Cl2, chloroform, formaldehyde, 

methanol)

-Deleted HCE from bleach plants

-Deleted o-xylene from pulp storage, recovery furnace

-Changed fugitive angle for WWT

NEI42341A 0234 -Added chloroform to AST system (tanks 1-3)

-Reduced chloroform from cooling towers, primary clarifier

NEI759 none Deleted HCE from brownstock washing/HVLC

NEI6450 none -Increased fugitive area for WWT and paper machines

-Reduced acetaldehyde, formaldehyde emissions from paper machines

-Changed latitudes/longitudes and fugitive angle for WWT, paper machines

NEI33135 & 

NEI706

none -Increased stack height, temperature, velocity/flow for decker, knotter, pulp storage, black 

liquor tanks, causticizing when changed release point type

-Reduced formaldehyde from white liquor processing

-Deleted records for brownstock washing (emissions go to power boilers) (includes 

acetaldehyde, formaldehyde, methanol, carbon tetrachloride)

-Changed release point type for decker, knotter, pulp storage, black liquor tanks, causticizing 

from fugitive to stack

NEI41552 none -Reduced stack height and velocity for paper machines (3 records)

-Increased acetaldehyde from paper machines (2 records)

-Replaced fugitive records for black liquor tanks with replacement stack records (no change in 

emissions) (2 unique records)

-Reduced acetaldehyde from paper machines (91 records) and ASB (1 record)

-Increased stack velocity/flow of black liquor tanks (4 unique records)

-Increased stack diameter for paper machines (3 unique records) and black liquor tanks (2 

unique records)

-Deleted acetaldehyde from primary settling basin

-Changed release point type for black liquor tanks from fugitive to stack (3 unique records)

-Changed latitude/longitude for ASB

-Recommended change to receptor location

-Changed SCC from 30700122 (causticizing miscellaneous) to 30700132 (green liquor 

processing)
A-8

NEI Code

Docket 

ID for 

NEI 

Revision Nature of the NEI Revision

NEI42357 none -Reduced acetaldehyde from ASB

-Reduced acetaldehyde, metals, naphthalene from LK

-Reduced arsenic from SDT

-Reduced metals from boiler

-Deleted acrolein, formaldehyde, acetaldehyde, naphthalene, methanol, 5 other HAPs from 

SDT

-Reduced fugitive area and increased release temperature for ASB

-Reduced stack diameter and calculated increased stack velocity for RF

-Changed latitudes/longitudes for ASB, RF, SDT, LK, boiler