## Kraft Pulp Mills New Source Performance Review (40 CFR Part 60

, Subpart BBa)

Final Amendments

Response to Public Comments on May 23, 2013 Proposal

U.S. Environmental Protection Agency Office of Air Quality Planning and Standards

Sector Policies and Programs Division Research Triangle Park, NC 27711

March 13

, 2014i 

## Table of Contents

Page

1. Introduction

................................ ................................ ................................ ................................ . 6 2. Technology Review

................................ ................................ ................................ .................... 8

2.1 General Comments

................................ ................................ ................................ ................ 8 2.2 Recovery Furnace, Lime Kiln, and Smelt Dissolving Tank Technology

........................... 13 2.3 Digester and Brown Stock Washer Technology

................................ ................................ . 26

3. Continuous Emission Monitoring System Data Review

................................ .......................... 31 3.1 Data Evaluation and Quality Analysis

................................ ................................ ................ 31 3.1.1 General Quality Analysis

................................ ................................ ................................ 31 3.1.2 Op erating Period

................................ ................................ ................................ ............. 33 3.2 Opacity Limits

................................ ................................ ................................ .................... 46

3.3 TRS Limits

................................ ................................ ................................ .......................... 48 3.4 Startup and Shutdown Performance Data

................................ ................................ ........... 49 4. Startup, Shutdown, and Malfunction

................................ ................................ ........................ 51 4.1 Periods of Startup and Shutdown

................................ ................................ ........................ 51

4.2 Periods of Malfunction

................................ ................................ ................................ ....... 80

4.3 Affirmative Defense

................................ ................................ ................................ ............ 86 5. Testing and Monitoring

................................ ................................ ................................ ........... 100 5.1 Emissions Testing

................................ ................................ ................................ ............. 100 5.2 Parameter Monitoring

................................ ................................ ................................ ....... 104

5.2.1 Incinerator Parameter Monitoring

................................ ................................ ................ 104 5.2.2 Recovery Furnace Parameter Monitoring

................................ ................................ ..... 106 5.2.3 Smelt Dissolving Tank Parameter Monitoring

................................ ............................. 108 5.2.4 Lime Kiln Parameter Monitoring

................................ ................................ ................. 110 5.2.5 Digester Parameter Monitoring

................................ ................................ .................... 111

5.3 TRS CEMS Data O 2 Correction Procedure

................................ ................................ ...... 111 5.4 Averaging Times

................................ ................................ ................................ ............... 117

5.5 Electron ic Reporting

................................ ................................ ................................ ......... 121 5.6 Other Testing and Monitoring Comments

................................ ................................ ........ 122 6. Cost and Impacts

................................ ................................ ................................ ..................... 126

7. Greenhouse Gas Emissions

................................ ................................ ................................ ..... 127ii 

## List of Tables

Page

Table 1. List of Commenters on 40 CFR Part 60, Subpart BBa, Proposed May 23, 2013 (78 FR 31316)

................................ ................................ ................................ .................. 7 Table 2. Typical Uncontrolled TRS Emissions from Salt Cake Mix Tanks and Processes Covered Under the Kraft Pulp NSPS

................................ ................................ ............. 15 Table 3A. Summary of Recovery Furnace COMS Data Sets Analyzed

................................ ....... 38 Table 3B. Summary of Lime Kiln COMS Data Sets Analyzed

................................ ................... 39 Table 3C. Summary of Recovery Furnace TRS CEMS Data Sets Analyzed

............................... 40 Table 3D. Summary of Lime Kiln TRS CEMS Data Sets Analyzed

................................ ........... 41 Table 4. Example Lime Kiln O 2 Corrections

................................ ................................ .............. 113



## List of Figures

Page

Figure 1. 99 th Percentile of the TRS Averaging Periods (NSPS and Non

- NSPS Furnaces)

....... 1 8 Figure 2. 99 th Percentile of the TRS Averaging Periods by APCD (NSPS Furnaces)

.. ............. 1 9 Figure 3. 99 th Percentile of TRS Averaging Per iods for Lime Kilns (NSPS Kilns Only............. 20 Figure 4. Opacity Monitor ing Allowance Data for Recovery F urnaces

........................... ......... 42 Figure 5. Opacity Monitoring Allowance Data for Lime Kilns

.............................................. 43 Figure 6

. TRS Monitoring Allowance Data for Recovery Furnaces Subject to the Subpart BB NSPS Limit (5 ppm)

............................................................................ . 44 Figure 7 . TRS Monitoring Allowance Data for Lime Kilns Subject to the Subpart BB NSPS Limit (8 ppm)

... ................................................................... .............. 45iii 

## List of Acronyms and Units of Measure

Act Clean Air Act

ADTP a ir

- d ried t on (s) of p ulp

ADTP D a ir

- d ried t on (s) of p ulp per d ay AF&PA American Forest & Paper Association

AFS EPA’s Air Facility System Agency U.S. Environmental Protection Agency

AIRS EPA’s Aerometric Information Retrieval System

ALAPCO Association of Local Air Pollution Control Officers

APCD air pollution control device

Ass’n Association

BACT best available control t echnology

BID b ackground i nformation d ocument
BLO black l i quor o xidation

BLRBAC Black Liquor Recovery Boiler Advi sory Committee

BL S black l iquor solids

BSER b est system of emission r eduction

BSW b rown stock w asher

CAA Clean Air Act

CaCO 3 calcium carbonate

CAM c ompliance assurance m onitoring

CaO c alcium o xide ( l ime)

CCA Clean Condensate Alternative

CDX EPA’s Central Data Exchange

CEDRI EPA’s Compliance and Emissions Data Reporting Interface

CEMS continuous e missions m onitoring s ystem

cert. certiorari (writ seeking judicial review)

c f. c onfer (compare)

CFR Code of Federal Regulations

CH 4 m ethane

Cir. Circuit Court

CMS continuous monitoring system

CO carbon monoxide

CO 2 carbon d ioxide

CO 2 e CO 2 e quivalents

c ol. c olumn

COMS continuous opacity monitoring system

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

CPM condensable PM

CPMS c ontinuous parameter m onitoring s ystem
CROMERR Cross Media Electronic Reporting Rule

CWA Clean Water Act

D

. C

. District of Columbia

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

DAS data acquisition system(s)iv

DBESP d ry

- b ottom ESP

DCE d irect c ontact e vaporator
d scf dry standard c ubic f oot

e.g. e xempli gratia (for example)

EPA Environmental Protection Agency

ERT Electronic Reporting Tool

ESP electrostatic p recipitator

etc. et cetera (and other things)

FIP Federal Implementation Plan

FR Federal Register

GHG g reenhouse g as GHGRP Greenhouse Gas Reporting Program

g r g rain(s)

H 2 S hydrogen s ulfide

HAP h azardous air p ollutant

hr hour

HVLC high

- volume l ow

- c oncentration

i.e. i d est (that is)

ICR i nformation collection r equest

i d. i dem (the same)

LAER l owest a chi evable e mission r ate
lb p ound

LVHC low

- volume h igh

- c oncentration

MACT maximum a chievable c ontrol t echnology

mg m illigram(s)

MMBtu million British thermal unit(s)

N 2 O n itrous o xide

Na 2 CO 3 s odium carbonate

Na 2 S s odium sulfide

Na 2 SO 4 s odium sulfate

NaOH s odium h ydroxide

NCASI National Council for Air and Stream Improvement , Inc.

NCG non

- c ondensable g as NDCE n on

- direct contact e vaporator
NESHAP n ational emissions s tandards for h azardous a ir p ollutants

No. Number

NO X n itrogen o xides

NRDC N atural Resources Defense Council

NSPS n ew s ource p erformance s tandards

NSSC n eutral s ulfite s emichemical

O 2 o xygen

p. page PM p articulate m atter

PM 2.5 PM ≤ 2.5 microns in diameter (fine PM)

pp. pages

ppm part(s) per m illionv

ppm d v p art(s) per m illion of dry v olume QA q uality a ssurance QC quality c ontrol

RACT r easonably a vailable c ontrol t echnology

RBLC RACT/BACT/LAER Clearinghouse

RTR residual risk and technology review

S/S startup(s) and/or shutdown(s)

SAB EPA’s Science Advisory Board

SCBR scrubber

scfm standard cubic f eet per m inute

SDT s melt dissolving t ank

SIP State Implementation Plan

SO 2 s ulfur d ioxide

SSM s tartup, shutdow n, and m alfunction

STAPPA State and Territorial Air P ollution Program Administrators tpd ton(s) per day
tpy ton(s) per t ear TRS t otal r educed s ulfur

U.S. United States

U.S.C. United States Code

v. v ersus VOC volatile organic c ompound

WBESP wet

- bottom ESP

WPR wet PM return

WWW World W ide Web6 

## 1. Introduction

Section 111(b)(1)(B) of the CAA requires the EPA to review and, if appropriate, revise existing

NSPS at least every 8 years. As part of the review, the EPA considers what degree of emission

limitation is achievable through the application of the BSER, which (taking into account the cost

of achieving such reduction and any nonair quality health and environmental impact and energy requirements) the Administrator determines has been adequately demonstrated. The EPA also

considers the emission limitations and reductions that have been achieved in practice.

In addition to conducting the NSPS review, the EPA evaluated the SSM provisions in light of the

D.C. Circuit Court of Appeals decision in Sierra Club v. EPA , 551 F.3d 1019 (D.C. Cir. 2008),

which held that the SSM exemption provisions in the General Provisions in 40 CFR part 63 violated the CAA’s requirement that some standard apply continuously. In the Sierra Club case, the D.C. Circuit vacated the SSM exemption provisions in the General Provisions of 40 CFR part

63 for non

- opacity and opacity standards. The Court explained that under section 302(k) of the CAA, emission standards or limitations must be continuous in nature. The Court then held that the SSM exemption violates the CAA’s requirement that some section 112 standard apply continuously. In light of the Court’s reasoning, all rule provisions must be carefully examined to

dete rmine whether they provide for periods when no emission standard applies. The EPA believes the reasoning behind the D.C. Circuit’s decision in Sierra Club v. EPA applies equally to CAA section 111 and section 129 rules. The EPA’s general approach to SSM pe riods has been used consistently in promulgating new NSPS standards under CAA section 111, and in section 112 and section 129 rulemaking actions, since the D.C. Circuit’s decision in Sierra Club . See,

e.g. , New Source Performance Standards Review for Nitri c Acid Plants, Final Rule , 77 FR 48433 (August 14, 2012); New Source Performance Standards for New Stationary Sources and Emission Guidelines for Existing Sources; Commercial and Industrial Solid Waste Incineration Units, Final rule , 76 FR 15704, (March 21 , 2011); Oil and Natural Gas Sector: New Source Performance Standards and National Emission Standards for Hazardous Air Pollutants Reviews; Final rules , 77 FR 49490, (August 16, 2012).

The NSPS for kraft pulp mills (40 CFR part 60, subpart BB) were promulgated in 1978 and last

reviewed in 1986. To address the latest NSPS review, SSM exemptions and other changes, the

EPA propos ed new standards on May 23, 2013 , which apply to affected sources at kraft pulp mills for which construction, modification or reconstruction commences after the May 23, 2013 proposal date. A 60

- day period ending July 23, 2013 was provided for the public to submit

comments to EPA on the proposal. The following sections of this document summarize the public comments received on the proposal and present EPA’s responses to those comments:

 Section 2

– Technology Review

 Section 3

– Continuous Emission Monitoring System Data Review

 Section 4

– Startup, Shutdown, and Malfunction

 Section 5

– Testing and Monitoring

 Section 6

– Costs and Impacts

 Secti on 7

– Greenhouse Gas Emissions7

A total of six separate sets of written comments were received on the proposal

. (See www.regulations.gov, D ocket ID N o. EPA

- HQ

- OAR

- 20 12

- 0 6 4 0 , 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 of the document numbers specific to each commenter are presented in this document ( e.g. , commenter 00 55 , instead of commenter EPA

- HQ

- OAR

- 20 12

- 0 640

- 00 55 ). One c ommenter
submitted comments in multiple documents a nd is identified by the number of the first document

submitted ( i. e. , commenter 0059 for documents 0059, 0060, and 006 2 )

.

Table 1 . List of Commenters on 40 CFR Part 60

, Subpart BBa, Proposed May 23, 2013 (78 FR 31316)

Docket ID No.

EPA

- HQ

- OAR

2012

- 0640 Commenter n ame Affiliation

0 0 55 E. Christopher

Abruzzo Pennsylvania Department of Environmental

Protection

0056 Stephen E. Woock Weyerhaeuser

0057 Vera P. Pardee and

Helen Kang Center for Biological Diversity, Greenpeace, Inc.,

and Port Townsend Air Watchers

0058 Vipin K. Varma National Council for Air and Stream Improvement
0059, 0060, 0062 Paul Noe American Fo rest & Paper Association

0061 Russell Frye SSM Coalition8 

## 2

. Technology Review

2. 1 General Comments

2.1

- 01 Comment : Commenter 0059 agreed with EPA’s decision not to include additional pollutants in its kraft pulp m ill NSPS review. According to the commenter, t he 8

- y ea r review provision in CAA section 111(b)(1)(B) by its terms addresses only review of existing standards, not imposing additional performance standards. 1 The commenter pointed out that the re is no

statement in the statute establishing any deadline for EPA to consider whether to adopt NSPS for

new pollutants or new emission sources not covered by the current regulations.

The commenter argued that EPA was not even required to complete a comprehensive review of

the current s ubpart BB regulations . According to the commenter, CAA section 111(b)(1)(B) gives EPA the option of determining that periodic review “is not appropriate in light of readily

available information on the efficacy” of the existing NSPS. 2 The com menter noted that they provided EPA with information that they believe d demonstrated that EPA could and should have

made such a finding, rather than going through a full review of the existing standards. 3

Noting that EPA nevertheless chose to conduct a review of the kraft pulp m ill NSPS , the commenter argued that EPA had broad discretion to determine the sources that it would evaluate

and the pollutants for which it would consider establishing standards. The commenter contended

that EP A’s decision not to expand the sources or the poll utants currently covered under s ubpart

BB was well within that discretion.

According to the commenter, EPA is under no obligation to add pollutants, nor to consider adding pollutants, to those already regulated under s ubpart BB. The commenter argued that

n othing in CAA section 111 requires that NSPS cover all pollutants emitted by a source, and that EPA has never interpreted it that way. 4 The commenter contended that , before expanding the

kraft p ulp m il l NSPS to cover additional pollutants, EPA would have to justify its departure from its prior decisions about which pollutants the NSPS should cover. 5 The commenter stated that

1 See also Portland Cement Ass’n v. EPA , 665 F.3d 177, 193 (D.C. Cir. 2011) (“it is unclear whether EPA has such a duty with respect to pollutants it has not previously regulated”).

2 See 78 FR 31 322.

3 See, e.g. , AF&PA November 22, 2011 comments on EPA’s October 24, 2011, proposed plan for periodic review of NSPS, 76 FR 65 655 ( document no. EPA

- HQ

- OAR

- 2010

– 0223

- 0008).

4 See, e.g. , National Lime Ass ’ n v. EPA , 627 F.2d 416, 426 (D.C. Cir. 1980) (observing that, while EPA had determined that lime plants were sources of NOx

, CO , and SO 2 as well as particulates, standards of performance were proposed and ultimately promulgated only for PM ); 70 FR 9706, 9711 (Feb. 28, 2005) (declining to set NOx

limits for boilers below 100 MMBtu /hr heat input, based on current emission levels, av ailable technologies, and costs); 74 FR 51950, 51957 (Oct. 8, 2009) (“The statutory scheme thus provides EPA with significant discretion to determine which pollutant(s) should be regulated under the NSPS.”); 75 FR 54970, 54996 (Sept

. 9, 2010) (declining

to set CO limits for cement kilns in part because new emission units “are designed to combust fuel as efficiently as possible, and CO emissions from fuel combustion are minimized, regardless of any potential emission limit”).

5 Clearly the fact that pulp mil l sources emit VOCs, NOx, CO, and GHGs, none of which are subject to emission limitations in the kraft pulp mill NSPS, has been known for many years. See, e.g. , RTI March 29, 2013 memorandum, Technology Review and Regulatory Options for the Kraft Pulp Mill NSPS , document no. EPA

- HQ

OAR

- 2012

- 0640

- 0048, p. 10. If EPA were required to include in NSPS every pollutant that is emitted by a source category, that objection to the kraft pulp mill NSPS should have been raised years ago.9

EPA is under no obligation to include pollutants in NSPS before EPA, in its dis cretion, determines that it has enough information to decide whether F ederal standards of performance are necessary or appropriate for the pollutant. 6

The commenter further argued that, a s a practical matter, there would be little benefit to expanding the number of pollutants subject to emission limitations in the kraft pulp m ill NSPS. First of all, the commenter pointed out that there are relatively few new affected facilities being constructed, and so there would be relatively little to be gained by EPA spending the resources to develop NSPS for additional pollutants. The commenter noted that EPA has recognized that this is an appropriate reason for choosing not to promulgate NSPS. 7 According to the commenter,

t here has not been a greenfield chemical pulp mill built in the U.S. in over 20 years. Because of a variety of factors, including stringent environmental controls and reduced access to forest fiber supplies due to land development and access to Federal forests, the commenter stated that there

almost certainly will be few if any new pulp mills built in the U.S. in the coming 8 years. Moreover, because of overcapacity, environmental regulations, and the like, the commenter said

that there likely will be only a few new subpart BB affected facilities inst alled in the next
8 years. The commenter pointed out that, i n the decade from 1990 to 1999, 21 new kraft recovery

furnaces and 25 new lime kilns came on

- line in the U.S. According to the commenter, from 2000

to 2010, only 3 new kraft recovery furnaces and 3 new lime kilns came on

- line (and one recovery

furnace and one lime kiln were at a mill that has since shut down). The commenter contended

that n ew source standard t echnology reviews should be more than adequate to assure that these

few new units use the best emission control technology.

Secondly, the commenter noted that other CAA regulations already comprehensively address

emissions from kraft pulp mills, such that adding pollutants to the k raft pulp m ill NSPS would provide little if any incremental benefit. According to the commenter, MACT standards in

40 CFR p art 63

, s ubpart S require mills to control emissions of volatile HAP s, through collecting and incinerating vent gases or using clean condensates to minimize re lease of volatile HAPs, which also controls VOC emissions (as do measures to minimize total reduced sulfur ( TRS ) emissions under the existing subpart BB NSPS). The commenter noted that EPA very recently completed a review and revision of those s ubpart S st andards. 8 The commenter pointed out that EPA has acknowledged, in its proposed plan for reviewing and prioritizing NSPS, that MACT standards result in effective control of criteria pollutants as well. 9

In addition, the commenter indicated that all kraft pulp mills are large enough sources of conventional pollutants to be above the “major station ary source” threshold for major source new source review requirements and that new source review regulations will require BACT or LAER

for pollutants (other than HAPs) at new and modified sources that might be addressed in current or revised kraft pulp mill NSPS . According to the commenter , the statutory criteria for those technology requirements make them at least as stringent as, and generally more stringent than

, NSPS.

6 Cf . 78 FR 31 321.

7 See 76 FR 65655, 65658

- 59 (Oct. 24, 2011).

8 See 77 FR 55698 (Sept. 11, 2012).

9 See 76 FR 65655, 65658

- 59 (Oct. 24, 2011); see also, e.g. , 75 FR at 54 996 (declining to set NSPS for VOC

emissions from cement kilns because VOCs would be adequately controlled by NESHAP limits on THC emissions).10

Moreover, the commenter stated that a number of recently promulgated or pending EPA regulations that are not specifically directed at pulp mills will impose additional limits on their emissions, because they will require further reductions from la rge sources of the types of pollutants emitted by pulp mills. According to the commenter, t hese regulations include, for example, more stringent ambient air quality standards and EPA requirements for implementation of those standards, such as the NOx SIP c all; visibility protection and regional haze programs; other regional pollutant transport programs; and Boiler MACT standards in 40 CFR p art 63

,

s ubpart DDDDD. The commenter contended that t hese and other programs will require pulp mills to spend billions of dollars on additional emission controls (for existing as well as new sources) in the coming years

.

Response: We acknowledge this comment in support of focusing the NSPS review on the

current standards for PM and TRS due for review under CAA section 111(b)(1)(B)

.

2.1

- 02 Comment : C ommenter 0059 stated that the EPA was justified in choosing not to expand
the list of “affected facilities ” covered by the kraft pulp mill NSPS

. According to the commenter

, as with adding pollutants to the list of those cove red by subpart BB , the CAA does not require EPA to review its previous decision not to include other emission units in the NSPS, nor does it require EPA to regulate, or even consider regulating, all emission units at a source category for

which EPA chooses to promulgate NSPS

. 10 The commenter noted that EPA in fact often has chosen to regulate only some emission units at industrial plants. 11

The commenter also noted that there is no reason for EPA to consider adding other affected

facilities to the kraft pulp mill NSPS because EPA regulated “all process gas streams which have

been identified as major sources of TRS compounds or particulate matter at kraft pulp mills” in the original subpart BB NSPS

, 12 and t hat conclusion remains valid today. The commenter noted

that EPA chose not to address boiler emissions w hen it initially promulgated the kraft pulp mill

NSPS

, even though they were a significant source of emissions at pulp mills, because EPA anticipated promulgating NSPS for industrial boilers

, 13 which have sin ce been promulgated, and

reviewed and revised

. 14 In addition, the commenter noted that EPA has also recently promulgated MACT standards for industrial boilers and process heaters. 15 The commenter also

noted that the NESHAPs applicable to kraft pulp mill processes, s ubparts S and MM, thoroughly regulate the process sources of volatile HAP and HAP metals, and therefore the sources of TRS

and PM , at kraft pulp mills, applying technology requirements at least as stringent as could be imposed under NSPS. Because the se NESHAPs already cover additional emission points not addressed by the NSPS , the commenter argued that there would be no practical benefit from adding those emission points to the kraft pulp mill NSPS , which the commenter said EPA had

re cognized. 16

10 See CAA section 111(a)

- (b).

11 See, e.g. , 73 FR 35 838, 35848, 35 868 (June 24, 2008) (adding fluid coking units, not previously regulated, to list

of affected facilities in Petroleum Refineries NSPS

12 See 41 FR 42012, 40 213 (Sept

. 24, 1976).

13 See i d . at 40 213.

14 See 40 CFR p art 60

, s ubparts Db and Dc.

15 See 40 CFR p art 63

, s ubpart DDDDD.

16 See 78 FR 31322.11

Response: We acknowledge this comment in support of focusing the NSPS review on the

current standards due for review under CAA section 111(b)(1)(B)

. The kraft pulp mill NSPS limits emissions of PM and TRS from the most significant and measurabl e sources of these emissions from kraft pulp mills that are not covered under other NSPS

, such as the boiler NSPS

.

2.1

- 03 Comment : C ommenter 0059 stated that the EPA was correct in determining not to expand NSPS to other chemical pulping processes. The commenter pointed out that, w hen subpart BB was originally promulgated, EPA considered setting standards for sulfite and NSSC pulping processes

, as well as for the kraft process. The commenter noted that EPA determined at

that time that there would be litt le benefit to establishing an NSPS for those types of mills, and

the commenter stated that the considerations that led EPA to that conclusion are even stronger today, noting that sulfite and NSSC pulping have become even less prevalent. 17

Response: We acknowledge this comment in support of continuing to focus the kraft pulp mill NSPS on mills that use the kraft pulping process , which is the predominant pulping process used by the most mills in the U.S

. We agree that the use of other chemical pulping pr ocesses is becoming less prevalent. 18

2.1

- 04 Comment : C ommenter 0057 argued that the technology

- forcing nature of section 111 requires EPA to consider all realistic means of emission control for each emission source in conducting its NSPS review

. According to the commenter, t he courts have indicated that EPA may consider emerging technologies and the benefits of raising standards to promote technology

innovation. 19 The commenter stated that EPA’s entire emission control technology review apparently considered only emission limitations achieved in practice by existing k raft pulp mills,

which the commenter said falls short of BSER. The commenter contended that o ther technologies exist and have been adequately demonstrated t o achieve additional emission

reductions and should be incorporated into the revised NSPS.

Response: We disagree that our analyses of the B S ER fell short of what is required under CAA

section 111. The technology review focused on the emission limitations that have been adequately demonstrated to be achieved in practice, taking into account the cost of achieving such reduction and any non

- air quality health and environmental impact and energy requirements . Determining the BSER th at has been adequately demonstrated and the emission

limitations achieved in practice necessarily involves consideration of emission reduction

methods in use at existing kraft mills. To determine the BSER, the EPA performed an extensive

review of several r ecent sources of information including :

 Process, equipment, and control device details from industry responses to EPA’s 2011 pulp and paper industry ICR;

17 U.S. Environmental Protection Agency. Screening Study on Feasibility of Standards of Performance for Two Wood Pulping Processes

. Document no. EPA

- HQ

- OAR

- 2012

– 0640

- 0029

. November 1978

. 18 Hanks, K., Holloway, T., and Gooden, C., RTI International. Projections of the Number of New, Modified, and Reconstructed Emission Units for the Kraft Pulp Mill NSPS Review . Memorandum to U.S. Environmental Protection Agency. February 4, 2013.

19 See, e.g. , Sierra Club v. Costle , 657 F.2d 298, 346 (D.C. Cir. 1981).12

 Permit limits from permits submitted with the ICR and collected from state agencies;

 RAC T/BACT/LAER C learinghouse ;

 A 20 1 0 European Commission document titled Integrated Pollution Prevention and Control (IPPC): Reference Document on Best Available Techniques in the Pulp and Paper Industry ;

 A document from STAPPA/ALAPCO titled Controlling Fine Particulate Matter Under the Clean Air Act: A Menu of Options ;

 Stack test data for PM and TRS;

 COMS data for recovery furnaces and lime kilns;

 TRS CEMS data for recovery furnaces, lime kilns, and NCG sources; and

 Technical bulletins prepared by NCASI, a major source o f environmental data affecting the pulp and paper industry

.

The conclusions from review of the above information are consolidated in a March 29, 2013 report titled, “ Technology Review and Regulatory Options for the Kraft Pulp Mill NSPS

, ”

available in D ock et ID No. E PA

- HQ

- OAR

- 2012

- 0640 . Additional reports that are also available in the docket provide a detailed discussion of the data sets and information sources described

above:

 Review of the Air Permits for Kraft Pulp Mills . April 26, 2013 ;

 Review of the Continuous Emission Monitoring and Continuous Opacity Monitoring Data from the Pulp and Paper Information Collection Request Responses Pertaining to Subpart BB Sources . April 5, 2013 ;

 Updated Review of the Continu ous Emission Monitoring and Continuous Opacity Monitoring Data from the Pulp and Paper ICR Responses for NSPS Sources

. February 28, 2014 ;

 Summary of RBLC and Other Findings to Support Section 111(b) Review of Kraft Pulp

Mill NSPS . October 18, 2012 ; and

 Emissions Test Data for the Kraft Pulp Mill NSPS Review . April 22, 2013

.

In our review of the ICR data, permits, the RBLC, and literature

, we looked for new and

innovative emission s reduction technologies that would result in greater emissions reductions than are currently required by the NSPS. In our comprehensive reviews of CEMS data and emissions test data, we looked specifically at the PM and TRS emission limitations that are achieved in practice at nearly all kraft mills. Next, we identified options f or reducing the promulgated NSPS emission limits and analyzed the impacts of r educing the limits

. 20 Based on

the analyses described above , the EPA is increasing the stringency of the NSPS PM limit for new

and reconstructed recovery furnaces; new and reconstructed SDTs associated with new and reconstructed recovery furnaces; and new, modified, and reconstructed lime kilns . The EPA is

also increasing the stringency of monitoring limits for opacity and TRS by tightening or placing

restrictions o f use of the monitoring allowances in the current NSPS. I n the sections below, we

20 Holloway, T. and Hanks, K., RTI International. Emissions Inventory for Kraft Pulp Mills and Costs/Impacts of the Section 111( b) Review of the Kraft Pulp Mills NSPS

. Memorandum to U.S. Environmental Protection Agency. February 4, 2013

.13

address commenters ’ specific examples of other technologies that they believe should have been incorporated into the NSPS review

.

2.1

- 0 5 Comment : Comment er 0056 noted that E PA generally did not find any advances in technology that were adequately demonstrated beyond certain more stringent emission limits for PM already established for the same types of sources and systems in 40 CFR part 63, subpart

MM. 21 As a result, the comme nter noted that EPA proposed to reset the NSPS for certain new and reconstructed sources to the same PM levels established for new sources in the NESHAP, and to adjust the PM limit only for modified lime kiln sources to the NESHAP existing unit

limit. The commenter supported the rationale that EPA used for the proposed emission limit changes

.

Similarly, c ommenter 0059 agreed with EPA’s conclusion in the preamble that the technologies being used to control PM and TRS emissions from sources regulated under NSPS subpart BB have not changed. The commenter noted that PM emissions are controlled by ESPs and

scru bbers, and TRS emissions are reduced using process controls, scrubbers, or incineration. According to the commenter, there have been no changes in the technologies used in the industry

since the last review of subpart BB (or since implementation of the pul p and paper MACT standards) to control PM, TRS, or any other criteria pollutants.

Response: We acknowledge the support of commenter 0056 for the proposed changes to the

numeric emission limits for PM and TRS , and the support of both commenters for our

con clusions regarding advances in technology . The EPA proposed to:

 Reduce the NSPS PM limit for new and reconstructed recovery furnaces from 0.044 gr/dscf to the new source PM limit of 0.015 gr/dscf found in the subpart MM NESHAP.

 Maintain the current NSPS TR S limits for recovery furnaces (5 ppmdv for straight recovery furnaces and 25 ppmdv for cross recovery furnaces ).

 Reduce the NSPS PM limit for new and reconstructed SDTs associated with new or reconstructed recovery furnaces from 0.2 lb /ton BLS to the new source PM limit of 0.12 lb/ton BLS in the subpart MM NESHAP.

 Reduce the NSPS PM limit for lime kilns from 0.066 gr/dscf for gas

- fired kilns and 0.13
gr/dscf for liquid

- fired kilns (in subpart BB) to the PM limits found in the s ubpart MM

NESHAP for all fuels, 0.064 gr/dscf for modified lime kilns and 0.010 gr/dscf for new or

reconstructed lime kilns.

 Maintain the current NSPS TRS limit for lime kilns at 8 ppmdv.

The reductions in the emission limits are being promulgated as proposed.



### 2.2 Recovery Furnace
, Lime Kiln , and Smelt Dissolving Tank Technology

2.2

- 01 Comment : Commenter 0057 argued that EPA must consider control techniques that are currently used in some mills when making the BSER determination for e missions from recovery furnace process units. According to t he commenter

, the process of mixing collected PM salt from

21 See 66 FR 3180

.14

a recovery furnace ESP with strong black liquor before the liquor is injected into the recovery furnace is a large source of TRS, VOC

, and HAP emissions at a kr aft pulp mill. The commenter stated that, i n the design of modern kraft recovery furnaces

, precipitator mix tanks are part of the recovery furnace process unit

. The commenter provided a real

- life narrative illustrating the sign i ficance of controlling the p rocess gases from the hot concentrated black liquor in recovery furnace precipitator mix tanks. 22

In the narrative , a malfunction cause d process gas from the mix tanks to be redirected from a

SDT to the recovery furnace

, resulting in a TRS excursion exceeding 5 ppm and complaints of strong odors. In response to the complaints and ongoing regulatory attention, the mill operator

re

- directed the precipitator mix tank process gas flow to an available HVLC vent system discharg ed to a combustion unit , eliminating the TRS, VOC, HAP

, and significant odors that had previously been emitted by the precipitator mix tank and discharged virtually uncontrolled from

the SDT low

- energy weak wash scrubber vent.

The commenter pointed to thi s re

- direction of gas from a precipitator mix tank to a combustion

unit a s an example of an enhanced control a lternative for TRS, VOC

, and HAP and noted that combustion units are widely used throughout the industry to control emissions. The commenter

con te nded that EPA must consider this technique for emissions reductions as part of its BSER determination. However, t he commenter no ted that they found no review and consideration of precipitator mix tank TRS and VOC process gas emissions within the proposed kraft pulp mill

NSPS.

T he commenter further suggest ed that the revised NSPS for kraft pulp mills should rule out precipitator mix tank designs at the base of ESPs that allow mix tank off

- gases to reach recovery

furnace fuel gas emission points, stating that such designs cannot meet section 111 requirements

for the BSER that has been adequately demonstrated.

Response: The commenter refers to emissions from salt cake mix tanks

, which are used to

collect the Na 2 SO 4 (salt cake ) and Na 2 CO 3 captured in the recovery furnace ESP for reuse in the pulping process in order to conserve chemicals

. The Na 2 SO 4 recycled back to the recovery

furnace is reduced to Na 2 S, a cooking liquor chemical, in the reducing zone of the furnace. Reprocessing of the Na 2 S and Na 2 CO 3 into cooking liquor continues in the SDT. 23

Emissions of TRS from salt cake mix tanks, and emissions of VOC and HAP

, were considered to

be outside the scope of this NSPS review because the review focused on the current PM and TRS

standards that were due for review under CAA section 111(b)(1)(B). In addition

, HAP s are regulated under the authority of a separate section of the CAA (section 112). Salt cake mix tanks are not known to be a source of PM ( i.e. , no PM data are available for salt cake mix tanks alone

uncombined with other exhaust streams ). Furthermore, salt cake mix tanks typically are not a significant source of TRS compared to the emission units currently regulated for TRS under the

22 This narrative concerns the 1200 tpd ADP bleached kraft pulp mill constructed by Champion International Corporation in 1986 in Quinnessec, MI.

23 U.S. Environmental Protection Agency. Technical Support Document: Chemical Recovery Combustion Sources at Kraft and Soda Pulp Mills. Office of Air Quality Planning and Standards. Research Triangle Park, NC. Publicat ion

No. EPA

- 453/R

- 96

- 012. October 1996. p. 5

- 13.15

NSPS, as shown in Table 2

. Similarly, emission factor ca lculations reveal that typical emissions of VOC and HAP (methanol) from salt cake mix tanks a re also less than 1 tpy

.

Table 2 . Typical Uncontrolled TRS Emissions from Salt Cake Mix Tanks and Processes Covered Under the Kraft Pulp NSPS

Process TRS e missions, t p y a
Recovery furnace b 2

, 700 Condensate stripper system 360 Digester system 270 Evaporator system 180

Lime kiln 144 BSW system 54

SDT 36

BLO system 18

Salt cake mix tank c 0.6

a. Uncontrolled emissions of TRS are based on information in Table 2.1 (p. 2

- 5) of the 1983 NSPS review BID,

entitled Review of New Source Performance Standards for Kraft Pulp Mills

, Publication No. EPA

- 450/3

- 83

- 017

, September, 1983. Emission estimates are ba sed on a kraft mill producing 1 000 ADTPD

, operating 360 days per year. Conversions used included 1.6 tons BLS/ ADTP and 0.275 tons lime ( CaO )/ A DTP

. b. Based on a range of data from DCE and NDCE recovery furnaces.

c. Salt cake mix tank emission estimates are based on a TRS emission factor of 0.0022 lb sulfur /ton BLS in

NCASI Technical Bulletin No. 849 (August 2002).

We provide typical emissions estimates for salt cake mix tanks above. Howev er, we acknowledge that there can be variability in equipment configuration and emissions from mill to

mill. The commenter describ es a malfunction event caused by blockage of the process gas evacuation in gas flow to the SDT vent at one mill as a reason why they believe salt cake mix

tanks should be covered under the NSPS . T he EPA does not consider malfunction s to be valid operating condition s for which emission standards are set. The pulp and paper ICR data collected by EPA confirms that the mill noted by the commenter continues to route salt cake mix tank

emissions to their HVLC system for control, and therefore has resolved the pro blem noted by the

commenter . The ICR data also indicate that the practice of routing salt cake mix tank emissions through a collection system to incineration

- based control is used for approximately 20 percent of salt cake mix tanks in the kraft pulping ind ustry ( e.g. , tanks where variability in operations may have led to odors the mill has opted to eliminate )

. Considering the typically low emissions from salt cake mix tanks and the variability in operations from mill to mill, the fact that some mills

have o pted to route salt cake mix tank emissions to their HVLC collection system for

incineration

- based control does not necessarily mean that this practice is reasonable for a ll kraft

mills

, as we show below.

The annualized cost for HVLC systems was recently estimated to be $1.89 million per year. 24 A typical HVLC system designed for subpart S regulated equipment handles around 133,525

24 Holloway, T., Hanks, K., and Gooden, C., RTI International. Costs, Environmental, and Energy Impacts for the Promulgated Subpart S Risk and Technology Review . Memorandum to U.S. Environmental Protection Ag ency. May 15, 2012.16

scfm

. 25

, 26 The average flow rate of uncontrolled vent gas streams from salt cake mix tanks is 5,045 scfm b ased on the 2011 ICR responses. T he average flow of exhaust fro m salt cake mix

tanks is about 4 percent of the typical HVLC gas flow

. Adding this exhaust stream would require new stainless steel duct work (and the associated moisture removal and pressure relief components)

. Co nsidering that HVLC system costs are related to the gas flow transported, t he

estimated cost of the additional components to an HVLC system to accommodate the salt ca ke mix tank would be roughly $71,0 00 for 1 ton of TRS emissions controlled ( e.g. , $71,000 / ton)

, assuming an incineration device is available to acce pt the salt cake mix tank gas flow. If additional incineration capacity would be required, costs would rise significantly. Thus, even though salt cake mix tanks were not addressed in the proposed NS PS review, after further analysis

, we conclude in response to this comment that it would not be cost

- effective to regulate TRS (or VOC) emissions from salt cake mix tanks under the NSPS.

2.2

- 02 Comment : Commenter 0057 argued that the proposed rule failed to fully consider changes in technology since the last review, resulting in a 5 ppm TRS limit for recovery furnaces

that is very likely too lax . The commenter noted that when the standard was first promulgated in 1978, it was based on the use of direct contact black liquor evaporation, black liquor oxidation, and control of black liquor sulfidity. 27 The commenter pointed out that, while modern mills still rely on control of sulfidity as a process

- specific means of l imiting TRS emissions and controlling pulping process chemistry, direct contact evaporation and black liquor oxidation is outdated technology

, and no new kraft recovery furnaces will be constructed in this fashion.

The commenter argued that the 8 ppm TRS standard for lime kilns is also based on old technology

. The commenter noted that under the 1978 rule, a lime kiln would comply through

the maintenance of effective lime mud washing, good operational and combustion practice, and wet scrubbing (which was not required to be caustic scrubbing). 28 However, according to the

commenter, EPA made very clear in the final rule that caustic scrubbing was an appropriate and

demonstrated control for H 2 S and TRS emissions that performed in a superior manner t o non

caustic assisted wet scrubbing for TRS control , b ut EPA did not explain why it did not require caustic scrubbing for TRS control, even th ough it was the demonstrated BSER

. The commenter

recommended that the lime kiln TRS standard be revised to reflec t the fact that today’s lime kilns are designed with greater TRS control technology and that c austic scrubbing is a demonstrated

BSER for TRS.

Response: In general

, we disagree with the commenter that we have not considered modern technology. We performed an extensive review of recent information on the processes, emissions controls, and emission data for the pulp and paper industry. This information was obtained by EPA through a very detailed ( and costly ) ICR completed by the pulp and paper industry in 20 11.

25 Oommen, R., Radian Corp. Changes made to the Design and Unit Costing o f Equipment used to Transport, Treat, and Control Emissions from Pulp and Paper Vents. Memorandum to U.S. Environmental Protection Agency.

Docket ID No. A

- 92

- 40, item IV

- B

- 13. February 26, 1996.

26 The 133,525 scfm value is the sum of gas flows from HVLC components, including weak liquor storage tanks, knotters/screens, deckers, pulp storage tanks, vacuum washers, and associated tanks and chests, and O 2 delignificati on for a kraft mill processing 1000 ADTPD.

27 Kraft Pulp Mills Standards of Performance for New Stationary Sources , Final Rule, 43 FR 7568 (Feb. 23, 1978).

28 Id.17

Our review of the ICR data, permit limits, the RBLC, and other relevant literature is documented in a series of technical reports available in D ocket ID No. EPA

- HQ

- OAR

- 2012

- 0640 , including:

 Review of the Continuous Emission Monitoring and Continuous Opacity Monitoring Data from the Pulp and Paper Information Collection Request Responses Pertaining to Subpart BB Sources . April 5, 2013

 Updated Review of the Continuous Emission Monitoring and Continuous Opacity Monitoring Data from the Pulp and Paper ICR Responses for NSPS Sou rces

. F ebruary 28, 2014

 Emissions Test Data for the Kraft Pulp Mill NSPS Review . April 22, 2013

 Summary of RBLC and Other Findings to Support Section 111(b) Review of Kraft Pulp

Mill NSPS . October 18, 2012

 Review of the Air Permits for Kraft Pulp Mills . April 26, 2013

 Technology Review and Regulatory Options for the Kraft Pulp Mill NSPS . March 29,

2013

 Review of Pulp and Paper Information Collection Request (ICR) Responses Pertaining to Startup and Shutdown of Subpart BB Equipment . M arch 22, 2013

 Projections of the Number of New, Modified, and Reconstructed Emission Units for the Kraft Pulp Mill NSPS Review. F ebruary 4, 2013

 Emissions Inventory for Kraft Pulp Mills and Costs/Impacts of the Section 111(b) Review of the Kraft Pulp Mills NSPS. February 4, 2013

 Economic Impact Analysis for the Section 111(b) Review of the Kraft Pulp Mills New Source Performance Standards Subpart BB . February 22, 2013

This extensive body of information builds on and supersedes conclusions from the 1978 original

NSPS and 1986 NSPS review.

Recovery furnaces

. We agree with the commenter’s assessment that there will never be a new DCE recovery furnace and associated BLO system in the U.S . The last of these systems was

installed in 198 9 . Non

- direct contact e vaporator recovery furnaces are now the prevailing design. The original NSPS promulgated in 1978 considered DCE with BLO and NDCE recovery furnace designs and concluded that a TRS limit of 5 ppm reflected the best demonstrated technology ( i.e. , use of an N DCE or DCE with sufficient black liquor oxidation to meet 5 ppm)

. This limit

was reaffirmed i n the 1986 NSPS review , and was reaffirmed again in the 2013 proposed NSPS review based on review of a very comprehensive TRS CEMS data set for rec overy furnaces i n use today ( roughly 3/4 of which are NDCE recovery furnaces). Given the extensive data set

evaluated , w e disagree with the commenter that we did not evaluate the performance of to d a y’s recovery furnace technology. We considered data from all recovery furnaces and then focused only on the recovery furnaces that have triggered NSPS to examine the performance of newer or upgraded recovery furnac es relative to the 5 ppm limit. Figure 1 below shows the 99 th percentile of the TRS concentrations measured by C EMS for each recovery furnace , including recovery furnaces that are not currently subject to NSPS

. 29 Figure 1 shows that most DCE recovery furnaces do not perform as well on TRS as NDCE recovery furnaces. Non

- NSPS recovery

29 The 99 th percentile indicates the emission limitation consistently met by each emission unit considering emissions variability ( i.e., 99 percent of the TRS averages measured by the CEMS were at or below the 99 th percentile value shown for each recovery furnace).18

furnaces are not subject to the sa me low TRS limit as NSPS furnaces. Figure 2 presents the 99 th
percentile TRS concentrations for the recovery furnaces subject to the subpart BB NSPS broken out by DCE and NDCE design and control device type

. Two of the three DCE recovery furnaces subject t o subpart BB had 99 th percentile TRS values above the 5 ppm limit, while the majority of NDCE recovery furnaces met the 5 ppm limit regardless of control device design. Based on the data in Figures 1 and 2, we agree with the commenter that DCE recovery fur naces do not perform as well on TRS as NDCE recovery furnaces and that DCE recovery furnaces would be challenged to meet a 5 ppm TRS limit. Thus, we can conclude based on the data that the 5 ppm NSPS TRS limit effectively deters installation of new DCE rec overy furnaces. Any DCE recovery furnaces that trigger NSPS through modification or reconstruction are expected to either convert to NDCE technology or use another means of demonstrating compliance with the 5 ppm limit ( e.g. , through improved process controls, additional black liquor oxidation stages, and switching to oxidized black liquor in the wet

- bottom ESP). In either case, modified and reconstructed recovery furnaces are held to the same level of performance as NDCE recovery

furnaces.

Figure 1. 99 th Percentile of the TRS Averaging Periods (NSPS and Non

- NSPS Furnaces)19

Figure 2. 99 th Percentile of the TRS Averaging Periods by APCD (NSPS Furnaces)

Lime kilns

. Based on our evaluation of an extensive TRS CEMS data set and other literature, we disagree with the commenter that caustic scrubbing represents the BSER for lime kilns

. Lime kiln control technology has evolved since promulgation of the NSPS in 1978, as has the pool of available emissions data upon which we based our conclusions for the 2013 proposed NSPS

review. In addition to good mud washing and operational practice s, t oday’s lime kiln control technologies inclu de wet scrubbers, ESPs, and ESP/ scrubber combination controls. Electrostatic precipitators are becoming increasingly common for lime kiln PM control. We evaluated all of

these control systems for the proposed NSPS review and found that wet scrubbers (regardless of

c austic addition), ESPs, and ESP / scrubber combinations all performed similarly with regard to

TRS . The fact that ESP

- controlled kilns performed as well as scrubber

- controlled kilns (when ESPs are not designed for TRS control) suggests that process factors such as mud washing and good com bustion of NCGs are important factors in reducing lime kiln TRS emissions. Figure 3

below affirms that 8 ppm is the emission level that has been achieved in practice and adequately

demonstrated as the BSER. 30

30 Spence, K., U.S. Environmental Protection Agency. Updated Review of the Continuous Emission Monitoring and Continuous Opacity Monitoring Data from the Pulp and Paper ICR Responses for NSPS Sources

. Memorandum to
Docket ID No. EPA

- HQ

- OAR

- 2012

- 0640. Februar y 28, 2014

.20

Figure 3. 99 th Percentile of TRS Averaging Per iods for Lime Kilns (NSPS Kilns Only)

One issue with wet scrubbers is that the scrubbing liquid m u st not introduce reduced sulfur compounds into the lime kiln exhaust gas stream. Lime kiln scrubber makeup water can be a

source of TRS emission s if the scrubber uses process water ( e.g. , process condensates)

contaminated with reduced sulfur compounds. Reduced sulfur compounds can be stripped from the scrubber makeup water as the hot kiln flue gases pass through the scrubber. Caustic (or weak wash) scrubbing is not effective on all TRS compounds and is not necessary to achieve the 8 ppm limit. 31

Review of lime kiln TRS emissions data and the technologies used to reduce TRS emissions from lime kilns suggests that use of process controls such as good l ime mud washing and avoidance of scrubbing liquid contaminated with reduced sulfur compounds continues to be adequately demonstrated as the BSER

.

2.2

- 03 Comment : C ommenter 0059 agree d that it is appropriate to revise the PM and opacity

limits in subpart BB a for new and reconstructed lime kilns and recovery furnaces to match the PM and opacity limits in MACT s ubpart MM . The commenter noted that t he new source PM and opacity limits in MACT s ubpart MM are more stringent than those in NSPS subpart BB and that these limits represent what new and reconstructed kilns and furnaces have achieved and th at th e units would have to meet the new source MACT standards anyway. The commenter further

noted that the re is no cost impact for this change

.

31 Hanks, K. and Holloway, T., RTI International. Technology Review and Regulatory Options for the Kraft Pulp

Mill NSPS. Memorandum to U.S. Environmental Protection Agency. March 29, 2013.21

The commenter also agr ee d that it is appropriate only to change the PM limit for

new/reconstructed SDTs that are associat ed with new recovery furnaces. The commenter noted

that f acilities often replace or reconstruct existing SDTs without modifying the associated recovery furna ce or modifying the existing SDT scrubber. Therefore, the commenter agreed that

it is not cost

- effective to lower the PM limit for these units because a lower PM limit would likely require a scrubber replacement for a reconstructed SDT

.

Response: We ackno wledge th e comment in favor of the proposed limits for new and

reconstructed lime kilns and recovery furnaces. The numeric values for the PM and opacity limits for lime kilns and recovery furnaces are being promulgated as proposed. We also acknowledge the commenter’s agreement with our conclusion to reduce the PM limit from 0.2 to

0.12 lb/ton BLS for new and reconstructed SDTs that are associated with new recovery furnaces

. The numeric limits for SDTs are being promulgated as propose d.

2.2

- 04 Comment : C ommenter 0057 contended that EPA’s discussion of TRS emission control is flawed, since it incorrectly assumes that the terms “white liquor scrubber,” “caustic scrubber

, ” and “wet scrubber” all are directly equivalent and interchangeable when addressing TRS emission control for lime kilns, SDT vents

, and recovery furnaces

. A ccording to the commenter,

a ll white liquor scrubbers and caustic scrubbers are wet scrubbers , but a wet scrubber using water

is never co nsidered as a caustic scrubber or white liquor scrubber. The commenter further noted

that a ll white liquor scrubbers are caustic scrubbers

, but a caustic scrubber using only sodium or potassium hydroxide is not a white liquor scrubber. Commenter 0057 noted that w hite liquor scrubbers use white liquor, which is a solution of Na 2 CO 3 , Na 2 S, and NaOH obtained from the

kraft pulp mill process, for re

- circulating wet scrubbing systems. The commenter argued that

g rouping together white liquor scrubbers, caustic sc rubbers

, and wet scrubbers that only use water instead of caustic compounds is a technical error because they do not have equivalent

emiss ion control reduction effects. The commenter recommended that these scrubber types be addressed as separate categories for TRS emission s data review, control efficacy

, and analysis, and each should be separately analyzed for purposes of the final rule on required emissions

limitations.

According to the commenter, the reason this distinction is important is that the substantial Na 2 S

contained in re

- circulating white liquor scrubbers will cause formation of H 2 S

, Na 2 CO 3 , and

Na 2 SO 4 in the flue gas from reactions with CO 2 and water contained in the recovery furnace and lime kiln flue gas. The commenter stated that, d ue to this chemical reaction, EPA cannot accurately conclude that white liquor scrubbing, caustic scrubbing

, and scrubbing with water all

have the same emission control efficacy and thus the same percent age reduction control for H 2 S emission concentrations relative to the inlet gas stream H 2 S and methyl mercaptan

concentrations.

The commenter concluded that EPA must analyze whether the control technology level achieved by caustic scrubbing for TRS contro l on lime kilns, recovery furnaces, and SDT vents does in

fact constitute the BSER as required by section 111. The commenter recommended that EPA require caustic scrubbing wet scrubber control of TRS (as opposed to white liquor scrubbing) in

the final rule and establish that position by ensuring appropriate subcategorization of its TRS22

emission control database analysis determination on each process unit under the rule and in all

emissions database analyses.

Response: The commenter appears to be confused by the complexities of the kraft pulping

process, the location and types of emissions controls that can appear within the process v

. end

- of

pipe, and the summary of findings from our technology review that was condensed co nsiderably for the preamble. The technical memoranda in the docket for the proposed rule explain the subject matter in greater detail. We also explain the differences in scrubber types here in response to this comment.

“ White liquor ” is a solution of NaO H and Na 2 S that is used for cooking wood chips. “ White liquor scrubbers ” are not end

- of

- pipe controls used on recovery furnace or lime kiln flue gases as

describ ed by the commenter. White liquor scrubbers are in

- process scrubbers installed at some mills to reduce sulfur in an NCG stream prior to incineration of that stream in a combustion

device. White liquor scrubbers may also be referred to as “NCG scrubbers” or “NCG pre

scrubbers.” The intended purpose of white liquor scrubbers is to remove sulfur compounds from NCG streams prior to combustion in order to reduce SO 2 emissions that result from combustion

of TRS

- laden NCG streams. The effectiveness of white liquor scrubbers has been determined to be process

- specific and dependent on the molecular makeup of the NCG stream scrubbed. As part of the NSPS review, EPA evaluated whether use of white liquor scrubbers prior to

incineration of TRS results in reduced emissions of residual TRS following combustion. The

EPA found no c onclusive evidence that white liquor scrubbing reduces post

- combustion TRS

emission s. 32

“W et scrubbers

, ” as we refer to them in the NSPS review documentation are end

- of

- pipe scrubbers regardless of the scrubbing liquid used

, whether water alone or water with addition of caustic or other liquids. Kraft pulp mills are large industrial users of water, so mills recycle and reuse water within their processes whenever possible without causing adverse effects. Often

, mixtures of fresh water and other process l iquids are used for scrubbing. The ICR requested data on scrubbing liquid, and a wide variety of responses were received which do not group neatly into “water only” or “caustic” scrubbers . There are many differe nt sources of scrubbing liquid and process

- sp ecific ranges in concentrations of caustic that could be added to scrubbing liquids

or are already present in liquids recycled from another process

. Some common scrubbing liquids

are described below.

 “ Water ” can be various forms of mill water including sur face water ( e.g. , from a

river ), groundwater, and/ or water that has already been used in some aspect of the

process.

 “ Condensates ” are process liquids that condense from various pulping processes which may be treated for removal of HAP and reduced sulfur c ompounds with condensate strippers or in

- process biological treatment systems

. Treated “clean”

condensates and other condensates with low concentrations of nuisance compounds are often reused in the pulping process as scrubbing liquid or for another purpos e.

32 See Figure 7 of the February 28, 2014 EPA memorandum e ntitled Updated Review of the Continuous Emission Monitoring and Continuous Opacity Monitoring Data from the Pulp and Pa per ICR Responses for NSPS Sources

, Appendix E, for NSPS kilns with no NCG, NCG, and pre

- scrubbed NCG.23 Care must be taken to avoid use of contaminated condensates ( i.e. , condensates with a high concentration of reduced sulfur compounds) in scrubbers

, as this would result in

TRS emissions.

 “Weak wash” is the lime mud washer filtrate. Lime mud is predomina ntly CaCO 3

. Weak wash is often used in SDT scrubbers and then drains into t he SDT

, where the weak wash dissolves recovery furnace smelt. Based on the ICR data

, we observe that

w eak wash typically has a pH of 10 or greater. Additional alkali (caustic) may be added if necessary to further increase the pH of the scrubbing medium.

As discussed in a previous response, TRS CEMS data for wet scrubbers on lime kilns subject to the NSPS exhibited similar performance regardless of scrubbing liquid used

, so it was no t necessary to distinguish among scrubber types, especially given that wet scrubbers are not the only lime kiln control technology in use today. Based on the data

, we can conclude that caustic scrubbing is not the one and only BSE R for TRS from lime kilns

. Review of lime kiln TRS emissions data and the technologies used to reduce TRS emissions from lime kil ns shows that use of process controls such as good lime mud washing and avoidance of scrubbing liquid contaminated with reduced sulfur compounds represen ts the BSER.

Wet scrubbers are only present on 6 of the 149 recovery furnaces in the U.S.

, including 3 DCE furnaces and 3 NDCE furnaces. Four of the scrubbers are preceded by a recovery furnace ESP
system. Regardless of whether the scrubbing fluid used con tained caustic , scrubber

- controlled recovery furnaces did not achieve TRS emissions lower than their ESP

- controlled counterparts.

Thus

, we can conclude that caustic scrubbing does not constitute BSER for TRS from recovery

furnaces.

Similarly, caustic scrubbing alone does not constitute the BSER for SDTs. In our NSPS review, we concluded that variability in SDT TRS emissions can be attributed to process factors unique to individual facilities, that no one specific process factor alone dictates TRS emiss ions from mill to mill, and that control of SDT TRS emissions depends on more than scrubbing alone ( i.e. , the scrubbing solution, scrubber variables, and site

- specific process parameters all play a role). The TRS emissions arise from the sulfide present in the smelt and in the scrubbing liquid. Scrubbers with scrubbing solution that is high in sulfides can contribute to TRS emissions rather than reducing them. Therefore, the BSER for SDTs was determined to be the use of water that is not highly contaminated with dissolved sulfides for dissolving the smelt and for scrubbing. In addition to ensuring that the scrubbing and smelt dissolving liquid is not contaminated with sulfides, TRS removal can be enhanced through use of an alkaline scrubbing medium at mills where the principle TRS compounds are acidic ( e.g. , H 2 S, and to some extent methyl mercaptan). Review of the ICR data base indicates that the vast majority of SDTs are using alkaline solutions such as weak wash or a combination of water (or weak wash) and caustic as the scrubbing

medium. 33

Whether or not a salt cake mix tank vents into the SDT for control by the SDT scrubber could

also affect SDT emissions at some mills

, depending on the concentration and specific TRS compounds attributable to the salt cake mix tank. As mentioned elsewhere, one mill found it necessary to implement a process change to remove a salt cake mix tank vent from the SDT

33 Hanks , K. and H olloway, T., RTI International

. Technology Review and Regulatory Options for the Kraft Pulp

Mill NSPS

. Memorandum to U.S. Environmental Protection Agency. March 29, 2013.24

scrubber system in order to meet the SDT TRS limit

. However, this is not typical of salt cake

mix tank emissions fr om all mills , and the configuration of the salt cake m ix tank vent with respect to the SDT can be different from mill to mill ( e.g. , some may route salt cake mix tanks to the SDT scrubbers, others may not)

.

The current NSPS limit for TRS emissions from SDTs is 0.033 lb as H 2 S/ton BLS. The original

1976 SDT TRS limit of 0.0168 lb/ton BLS was raised to 0.033 lb/ton BLS during the 1986 NSPS review because some SDTs with wet scrubbers could not meet the original limit

. During the 1986 NSPS review, it was determined that there was a larger range of variation in TRS emissions

from well

- controlled SDTs than indicated by data obtained during NSPS development.

Rather than attempt to estimate and account for every equip ment design and operating variable in SDT and scrubber systems that could potentially affect TRS emissions, we took the more direct and accurate approach of analyzing SDT TRS stack test measurements to evaluate the performance of today’s SDTs. Emissions te st data collected at the SDT scrubber stack account for all of the process

- and scrubber

- related fact ors that affect SDT emissions. A total of 106 TRS

stack tests performed between 1987 and 2011 (on 90 SDTs) were reviewed for purposes of the

NSPS review. A ll but seven of the tests were performed as recently as 2004. The TRS emissions

test data allowed us to determine the emission limitation that has been achieved in practice though the combination of process changes and controls that have been demonstrated at modern kraft mills. We determined that the emission limitation achieved in practice considering process variability and cost is 0.033 lb as H 2 S/ton BLS.

2. 2

- 05 Comment : C ommenter 0057 noted that SDT emissions could be substantially reduced through application of control methods used on other equipment at pulp mills. The commenter

noted that h istorically, the k raft pulp mil l sector has generally used low

- pressure scrubbing plus demisters, or demisters only, as the sole emission control techniques app lied to PM and TRS

emissions from SDT vents. According to the commenter, s uch PM and TRS emissions could be

better controlled by high

- energy wet scrubbing, spray towers, packed towers, and caustic

scrubbers and through process modification if the facility employ ed recovery furnace precipitator

salt

- strong black liquor mixing tanks that are v en ted to the SDT process vent. Th e commenter pointed out that s ome of these same controls are applied to other kraft pulp mill process equipment and could be applied to SDT process vents. The commenter recommended that EPA

evaluate these controls as part of its BSER determination.

Response: The commenter suggests that SDT emissions could be further reduced if SDTs employed various types of scrubbers ( i.e. , high

- energy wet scrubbers, spray towers, packed

towers, or ca ustic scrubbers) instead of low

- energy wet scrubbers or demisters, or presumably if

salt cake mix tanks we re not vented though the SDT. If a salt cake mix tank vent were remove d

from the SDT scrubber

, then t he salt cake mix tank would either be completely uncontrolled, or possibly routed through an HVLC collection system to incineration

- based control. We discuss ed the typical TRS and VOC emission reduction that could be achieved and high cost of routing salt cake mix tank emissions through an HVLC system in response to comment 2.2

- 01, where we

conclude d that this practice is not adequately demonstrated as the BSER considering cost

effectiveness.25

Regarding scrubber controls, we discuss ed caustic scrubbing of SDT emissions in response to

comment 2.2

- 04

, where we conclude d that caustic scrubbing alone is not the BSER and that additional process factors were accounted fo r through our analysis of recent stack test data

. Spray towers are a for m of low

- energy wet scrubber, having pressure drops that are typically lower than other types of scrubbers. 34 Various types of wet scrubbers are used that differ not only in their design ( e.g. , spray tower, venturi, packed

- bed

, etc. ), but in how they are op erated ( e.g. , operating pressure drop, type of scrubbing liquid used, pH, etc

. ). 35

The combination of scrubber design and operating variables makes each scrubber system

somewhat mill

- specific

, necessitating some level of generalization in nationwide analyses. Rather than attempt to account for every equipment design and operating variable , we analyzed SDT TRS stack test measurements to evaluate the performance of today’s SDTs. In our analysis

o f TRS stack test data for SDTs

, we grouped SDTs with demisters, packed

- bed scrubbers, and all other types of wet s crubbers separately

. Information on the type of scrubbing solution used during TRS emissions testing was limited in the stack test reports. Ho wever, review of the ICR data base indicated that the vast majority of SDTs in the U.S. are using weak wash or a combination of fresh water and caustic as the scrubbing medium. Figures D

- 1 and D

- 2 in our technology review presented the emissions test data for SDT scrubbers

. 36 We concluded based on the emissions test data and additional information from prior studies of SDT TRS emissions

that:

 The baseline level of SDT TRS emissions of 0.033 lb/ton BLS has been achieved in practice.

 The technological basis for this limit (use of water in the smelt tank and scrubber with low sulfide content) has not changed since the 1986 NSPS review.

 Because many SDTs have achieved levels below 0.0168 lb/ton BLS, it would be appropriate to evaluate the cost effectiveness an d environmental impacts of reducing the NSPS limit for new, modified, and reconstructed SDTs to the original NSPS and emissions guidelines level of 0.0168 lb/ton BLS

. 37

34 U.S. E nvironmental Protection Agency. Air Pollution Control Cost Manual

- Sixth Edition

. Publicatio n No. EPA

452/B

- 02

- 001. Section 6, Chapter 2

- Wet Scrubbers for Particulate Matter

. July, 15 2002. Table 2.1. Available at http://www.epa.gov/ttn/catc/dir1/cs6ch2.pdf

. 35 U.S. E nvironmental Protection Agency. Air Pollution Control Technology Fact Sheet: Packed

- bed/Packed

- Tower

Wet Scrubber . Publication No. EPA

- 452/F

- 03

- 015. July 15, 2003. Available at http://www.epa.gov/ttn/catc/dir1/fp ack.pdf

. U.S. Environmental Protection Agency. Air Pollution Control Technology Fact Sheet: Spray

- Chamber/Spray

- Tower

Wet Scrubber. Publication No. EPA

- 452/F

- 03

- 016. July 15, 2003. Available at

ht tp://www.epa.gov/ttn/catc/dir1/fsprytwr.pdf

. U.S. Environmental Protection Agency. Air Pollution Control Technology Fact Sheet: Venturi Scrubber. Publication

No. EPA

- 452/F

- 03

- 017. July 15, 2003. Available at http://www.epa.gov/ttn/catc/dir1/fventuri.pdf

. U.S. Environmental Protection Agency. Air Pollution Control Cost Manual

- Sixth Edition. Section 6, Chapter 2

- Wet Scrubbers for Particulate Matter . Publication No. EPA 452/B

- 02

- 001

. July, 15 2002. Available at http://www.epa.gov/ttn/catc/dir1/cs6ch2.pdf

. 36 Hanks , K. and Holloway, T., RTI International. Technology Review and Regulatory Options for the Kraft Pulp

Mill NSPS

. Memor andum to U.S. Environmental Protection Agency. March 29, 2013.

37 Id.26

We considered use of a high

- energy wet scrubber in our cost and impacts analysis. We concluded that the costs to upgrade to a high

- energy scrubber were not justified by the incremental TRS emission reductions that would be achieved (assuming the scrubber reduced

emissions from 0.033 to 0.0168 lb/ ton BLS). Although not justified for TRS, a high

- energy wet
scrubber was determined to be the BSER for PM emissions from new and reconstructed SDTs associated with new or reconstructed recovery furnaces. The same high

- energy wet scrubbers

used for SDT PM control would also be used for SDT TRS con trol in the future.



### 2. 3 Digester and Brown Stock Washer Technology

2.3

- 01 Comment : Commenter 0057 argued that t he proposed rule has not fully evaluated the

actual TRS emissions reductions with combustion units or non

- combustion units. The

commenter conten ded that n on

- combustion units are typically not as effective for reducing TRS in discharge gases from digester systems, BSW systems, evaporator systems

, and condensate stripper systems. Thus, the commenter concluded that EPA must consider the actual reduct ions

achievable with combustion

- controlled systems and revise the TRS standard to ensure that all pulp mills are reducing TRS emissions accordingly.

The commenter also stated that the TRS limit should be expressed as a percentage reduction to

ensure that the emissions reductions available through the BSER are actually achieved at all pulp

mills. The commenter noted that the current TRS limit is expressed as 5 ppm , but pointed out

that emissions reductions with combustion units are typically in the range o f 98 percent to greater than 99 percent destruction efficiency for both TRS and VOC contained in the process

gases. The commenter concluded that t his percentage reduction may very well put TRS emissions consistently below 5 ppm

.

Response: Regarding the co mmenter’s statements about combustion versus non

- combustion technology, it appears that the commenter is referring to the TRS compliance option for digester,

BSW , evaporator, and condensate stripper systems in §60.283a(a)(1)(v)

, where a non

combustion cont rol device must meet a TRS limit of 5 ppm. In the proposal preamble, we stated that incineration remains the best demonstrated technology and t hat 5 ppm remains the appropriate limit , and noted that :

Alternatives to incineration, such as scrubbing, are less effective at the removal of TRS because only two of the four TRS compounds (H 2 S and methyl mercaptan) are acidic enough to be removed with alkaline scrubbing, resulting in a removal efficiency much lower than that achieved by incineration. 38

In response to the commenter, we note that the NSPS does not dictate which controls must be used, as long as the emission limit is met. The 5 ppm emission limit in §60.283a(a)(1)(v) for

non

- combustion is equivalent to the 5 ppm TRS emission limit for incinera tion

- based control in §60. 283a(a)(1). We identified only a few facilities using the 5 ppm non

- combustion TRS

standard in §60.283a(a)(1)(v) to show compliance

. Even though the vast major ity of facilities use

incineration

- based control , facilities are not pr ecluded from using other forms of control that

achieve the TRS emission limit. This construction of NSPS allows for innovation of new

38 7 8 FR 31322.27

technologies in the future that can show compliance with the same 5 ppm limit as required for

incineration

- based control.

We disagree with the commenter that the 5 ppm limit should be replaced with a percent reduction limit for several reasons. First, percent reduction requirements would not necessarily equate to emissions below 5 ppm. In circumstances where uncontrolled emi ssions are highly concentrated ( e.g. , 5000 ppm)

, a percent reduction would not reduce emissions to 5 ppm ( e.g. , a 99 percent reduction in concentration would be 50 ppm

, as compared to the currently required

5 ppm limit). E missions of this magnitude would n ot be unusual for kraft mill digester, evaporator, or condensate stripper systems if left uncontrolled

. Typical uncontrolled TRS concentrations from digester, evaporator, BSW, and condensate stripper systems would be or the

order of 9500, 6700, 30, and 500 0 ppm, respectively. 39 Thus, requiring a percent reduction instead of a 5 ppm limit, in most cases, would effectively relax the low TRS limits that have

reflected the level of control achieved in practice for over 30 years

.
Second, while it may seem that reducing low

- concentration gas streams by 99 percent would result in emissions below 5 ppm, this may not be reasonably achievable (considering cost, environmental, and energy impacts)

, as would a 5 ppm limit. Dilute gas streams such as a high

volume BSW ga s stream with a 30 ppm TRS concentration are more difficult and costly to control in a thermal oxidizer than concentrated gas streams because of the high air flow volumes

that must be incinerated

. 40 Large amounts of supplemental fuel would be needed to sust ain combustion of the dilute gas stream in a thermal oxidizer, which in turn would result in emissions of additional criteria po llutants and GHG s. Instead of prescribing a specific emission reduction be met, the NSPS contains multiple compliance options in cluding the 5 ppm TRS limit

or equ ivalent combustion of vent gases in process equipment such as lime kilns, recovery furnaces, or boilers where capacity of these devices to treat HVLC air flow volumes is available. Lime kilns, recovery furnaces, and boiler s do not suffer from the supplemental fuel requirements needed for thermal oxidizers and have been demonstrated in practice to achieve low TRS

emissions.

Finally, percent reduction limits would require periodic emissions testing at the inlet and outlet

of the control device, whereas continuous TRS monitoring in the stack is used to demonstrate compliance with the 5 ppm limit. Inlet

- outlet testing of TRS vent gas streams entering incineration devices poses a safety hazard and is particularly impractical for process equipment such as lime kilns, recovery furnaces, and boilers because outlet emissions are confounded by emissions from sulfur compounds that enter the process in other ways ( e.g. , with the BLS or lime mud). Measurement of inlet

- outlet concentration s is also complicated in situations where multiple inlet streams are introduced separately into the control device which has one comingled exhaust, or i n situations where gases from multiple emissions units are combined in a common duct that can be split a nd routed to more than one control device ( e.g. , a primary control device and backup control device),

2. 3

- 0 2 Comment : C ommenter 0057 recommended that the EPA clarify that digester process gases released into the interiors of buildings that house digester process equipment should be

39 U.S. Environmental Protection Agency. Review of New Source Performance Standards for Kraft Pulp Mills.

Publication No. EPA

- 450/3

- 83

- 017

. September 1983

. 40 Id.28

considered a discharge to the atmosphere. The commenter noted that digester process equipment, including continuous d igesters, chip bins, chip hoppers, knotter cyclones, low and high pressure feeders, pre

- steaming vessels, flash tanks, etc. are usually housed together in the digester process building , which also include s a ventilation system. The commenter further noted that c hip steaming is often used to charge digesters in k raft pulp mills, thereby making beneficial use of

low

- grade steam , but the common industry practice of using contaminated flash steam during chip steaming can also lead to the release of TRS, VOC

, an d HAP.

The commenter noted that the se emissions are typically first released int o the building that

houses the k

raft mill digester, and then released to the outside through building ventilation fans. According to the commenter , this occurs when the chip bin is charged with an excessive amount

of flash steam and the low pressure feeder from the chip hopper to the chip bin is breached with process gases entering the chip hopper. The commenter further noted that k notter cyclones are used to charge chip bins with incompletely digested wood knots that are recycled from the output of continuous digesters and digester blow

- down tank/pre

- brown stock pulp management. The

commenter stated that s uch cyclones are another potentia l source of emissions to the air in digester buildings.

The commenter also cited the following passage i n the proposed rule:

(a) On and after the date on which the performance test required to be conducted by §60.8 is completed, no owner or operator subj ect to the provisions of this subpart must cause to be discharged into the atmosphere

... 41 (emphasis added)

The commenter contended that t his language is vague and may allow for uncontrolled release of process gases from equipment inside of buildings that ar e not directly ducted to a vent or stack

on the exterior of the building. The commenter was concerned that t his terminology could be misinterpreted to mean that there must be an intentional, direct release of air pollutants to the outside atmosphere, which the commenter feared may create a loophole in some states to which EPA has delegated authority for NSPS implementation

. The commenter noted that, i n certain states, process gases emitted into the interior of buildings are considered solely under the purvi ew of occupational health regulation

.

Response: The proposed subpart BB a language “cause to be discharged into the atmosphere” applies for both captured and uncaptured (fugitive) emissions that are discharged into the atmosphere.

Federal air pollution regulations address the most significant sources of emissions from the pulp and paper industry, including captured emissions emitted through a conveyance and fu gitive emissions. Any remaining fugitive emissions not explicitly addresse d under Federal regulations that could potentially escape from digester buildings are likely to be very minor in comparison to regulated emissions

, and any such remaining emissions may be best characterized as episodic equipment leaks that are not part of normal operations. Such emissions would first pose an occupational hazard if they are emitted in significant concentrations , along with nuisance odors,

41 Kraft Pulp Mills NSPS Review , Proposed Rule, 43 FR 31336 (May 23, 2013) , citing proposed § 60.283a(a).29

and potential non

- compliance with air regulations (especially if a mill has interpreted the regulations loosely

, as the commenter contends )

.

We believe the broad language in the NSPS, which is further enhanced by the collection and control requirements under NESHAP subpart S, already ensure s that releases of air pollutants into digester buil dings from regulated equipment are subject to control. “ Digester systems ” are defined broadly in the NSPS to include each continuous digester or each batch digester used for the cooking of wood in white liquor, and associated flash tank(s), blow tank(s), ch ip steamer(s), and condenser(s). In addition, the NSPS contains broad definitions for other NCG

- producing equipment subject to the TRS limitations. For example, the definition of a “ brown stock washer
system ” includes BSW s and associated knotters, vacuum pumps, and filtrate tanks used to wash the pulp following the digester system. Thus, the equipment referred to by the commenter ( continuous digesters, chip bins, chip hoppers, knotter cyclones, low and high pressure feeders,

pr e

- steaming vessels, and flas h tanks) are addressed by the NSPS equipment definitions

.

Similarly, under the subpart S NESHAP, broad definitions cover the equipment referred to by the commenter. For example, under subpart S, the definition of an “emission point” includes open pieces o f process equipment and equipment leaks. As defined in subpart S, a “chip steamer” is a vessel used for the purpose of preheating or pretreating wood chips prior to the digester, using flash steam from the digester or live steam. A subpart S “knotter syste m” includes the knotter, knot drainer tanks, ancillary tanks, and any other equipment serving the same function. The subpart S NESHAP contains specific standards for capture of HAP emissions from affected facilities (see §63.450

– Standards for enclosures and closed

- vent systems) which involve VOC leak detection as a surrogate for HAP . T he subpart S NESHAP , which was promulgated in 1998, results in refined monitoring and control of NCG emission sources beyond that required in the

NSPS. Collection, control, and leak de tection of HAP emissions under s ubpart S results in collection, control, and leak detection of TRS emissions in the same NCG streams covered under

the NSPS. To ensure that the collection system requirements under subpart S are implemented under subpart BBa, and to promote consistency between these two Federal rules, we are revising §§60.283a(a)(1)(i)

- (iii) and (v) of the proposed subpart BBa to reference the § 63.450 collection system standards in subpart S. W e believe that the applicable Federal air regulations (NSPS and NESHAP together), combined with worker safety regulations, leave little opportunity for any significant emissions of TRS, VOC, or HAP from mod ern digester buildings.

In addition to incorporating the §63.450 standards for closed

- vent systems, as an outgrowth of this comment, we are changing the final NSPS to clarify that chip bins using live steam (flash steam) are considered to be chip steamers within the definition of digester system in the NSPS. Emission factor estimations show that the uncontrolled TRS emissions associated with digester chip bins using live steam are significantly greater than digester chip bins using fresh steam. For example , if uncontrolled, a digester chip bin could emit on the order of 40 t py TRS, while an uncontrolled digester chip bin using fresh steam would emit only 0.1 t py TRS. In light of these data, we are revising the NSPS definition of “digester system” to clarify that “chip steamer(s) including chip bins using live steam” are subject to the NSPS.

2. 3

- 03 Comment : C ommenter 0057 stated that t he proposed limits for TRS include an exemption for BSW s that could allow uncontrolled TRS emissions. The commenter noted th at
the proposed regulation states that BSW s do not have to comply with the TRS requirements if30

the Administrator is convinced that “incinerating the exhaust gases from a new, modified, or

reconstructed brown stock washer system is technologically or economically unfeasible.” 42

The commenter argued that t his subsection creates an impermissible exception based on

economic considerations. The commenter noted that s ection 111 directs the Administrator to take account of cost when making a determination of what constitutes BSER for each standard of performance. 43 Once the Administrator has determined what reductions are available under this standard, the commenter argued there is no longer a statutory basis for avoiding compliance

based on cost. The commente r contended that the subsection a s drafted opens the possibility of avoiding the statutory duty to implement the standards of performance.

The commenter further argued that the Administrator’s determination of what constitutes BSER has already established what constitutes BSER from a technical standpoint , so taking a second

bite at the apple in this subsection simply allows the circumvention of a determination already

made. According to the commenter , even if the exemption in the proposed regulation at § 60 .283a(a)(1)(iv) could be justified, it fails to explain what the alternative standard would be if an exemption were granted. The commenter cited the court ruling in Sierra Club v. EPA

, which

stated that Congress intended that “constant or continuous means of reducing emissions must be

used to meet these requirements. By the same token, intermittent or supplemental controls or other temporary, periodic, or limited systems of control would not be permitted as a final means of compliance.” 44 Although this case related to CAA section 112, the commenter argued the drafting of section 111 is highly analogous, which the commenter said EPA recognized in the proposed rule. 45

According to the commenter , the proposed regulation as it is currently draf ted does not state

what standard will apply to exempted BSW s. Th e commenter stated th a t th is must be remedied to ensure that, as required by law, adequate and continuous controls for TRS will be in place, even for exempt BSW s.

Response: The exemption codi fied in §60.283a(a)(1)(iv) continues the same exemption that EPA previously promulgated and codified in §60.283(a)(1)(iv) in Subpart BB. This exemption was originally promulgated in 1978 and was reconsidered and retained in the subsequent NSPS

review that was concluded in 1986. In this rulemaking, EPA did not invite comment on this exemption or otherwise reopen this exemption for comment, and is not reconsidering it.

42 Kraft Pulp Mills Standards of Performance for New Stationary Sources , Final Rule, 43 FR 7568 (Feb. 23, 1978).

43 See 42 U.S.C. 7 411(a)(1).

44 See Sierra Club v. EPA , 551 F.3d 1019, 1027 (D.C. Cir. 2008).

45 See Proposed Rule, supra, at 31317.31



## 3 . Continuous Emission Monitoring System Data Review

3.1 Data Evaluation and Quality Analysis

3.1.1 General Quality Analysis

3.1.1

- 01 Comment: In commenter 0058’s review of C EMS/CO MS data, the commenter found multiple instances of inclusion of erroneous/inappropriate data ( e.g. , negative values, values corresponding to “zero production,” etc. ), 46 some of which were also cited by commenter 0056. 47
Commenter 0058 acknowledged that the EPA was tasked with the analysis of a large quantity of fairly complex data set s in a short period of time. However, according to the commenter, the lack of consistency in applying QA/QC procedures has the potential to significantly impact the conclusions from this data analysis, especially given the need to ascertain that performanc e is “adequately demonstrated” even when including S/S periods. The commenter contended that a thorough review of NSPS unit performance that includes a consistent QA of all data, including

those related to S/S conditions, is essential in order to support t he “adequately demonstrated”

conclusion.

Citing the CEMS/COMS data review memorandum, 48 commenter 0058 contended that, while omitting abnormally large values that occur during periods of “process downtime” (zero production) is appropriate, the inclusion of any data used during “process downtime” can artificially skew the averages. Commenter 0056 cited a specific example where EPA included

zeros in its calculation of the 12

- hour block average for TRS for one of their mills. 49

Commenter 0058 noted that i nclusion of zeros during times of non

- operation not only artificially

lower s calculated averages but also inflate s the count of averaging periods containing numeric

data . According to the commenter, t he count of averaging periods with numeric data appears in the denominator when the percentage of periods exceeding a proposed limit (20 percent opacity

, 8 ppmdv TRS @ 10 percent O 2 , or 5 ppmdv TRS @ 8 percent O 2 ) is calculated. Thus, the

commenter noted that inclusion of these values in the analyses results in artificially low “monitoring exceedance” percentage calculations as well.

Response: The COMS and TRS CEMS data sets analyzed by EPA prior to proposal were provided as part of ICR responses. The ICR respondents handled erroneous/inappropriate monitoring data in a variety of ways: (a) some respondents replaced invalid measurements with text which prevented the data from being used in EPA’s calculations, (b) some respondent s added a note when invalid measurements occurred but did not remove the data, and (c) some respondents did not provide any indication when invalid measurements occurred. In response to comments on our analysis of the CEMS and COMS data, EPA scrutinized the data sets to ensure the following types of data were removed:

46 See comment 0058, p. 9.

47 See comment 0056, pp. 6

- 7.

48 U.S. Environmental Protection Agency. Review of the Continuous Emission Monitoring and Continuous Opacity Monitoring Data from the Pulp and Paper Information Collection Request Responses Pertaining to Subpart BB

Sources . Document no. EPA

- HQ

- OAR

- 2012

- 0640

- 0039. April 5, 2013.

49 See comment 0056, p. 7.32

 Negative opacity and negative TRS concentrati on measurements

 Measurements corresponding with periods of zero (or negative) production values or labeled as “process down” times

 Measurements recorded during monitoring system malfunctions, out

- of

- control periods

or r epairs, and monitor QA/QC checks, calibration checks, or zero or span adjustments to the extent that these time periods were labeled in the data sets.

The EPA also resolved double TRS O 2 corrections for units pointed out by commenters 0056 and

005 8 below

, rechecked calculation references

, ensured any O 2 correction calculations added to

the data sets were based on the 12

- hour average TRS concentration and 12

- hour average O 2 concentration (consistent with the rule), and updated other information as needed

.

The resultant “cleaned” data sets after removal of the erroneous/inappropriate data described above were used for further analysis of the promulgated standards. These data sets are described in an updated documentation memorandum , available in the docket for the final rule

. 50 The

cleaned data sets and revised memorandum replace and supersede the pre

- proposal data sets and analysis.

3.1. 2

- 03 Comment: Commenters 0056 and 0058 stated that some of the TRS data have been

double

- corrected for O 2 . Commenter 0058 noted that i n the CEMS/COMS data review

memorandum

, 51 the EPA assumed that the data submitted in certain TRS CEMS datasheets were

uncorrected because the percent O 2 c orrection data provided in the adjacent column of the spreadsheet(s) were not reported as 8 percent or 10 percent . The co mmenter indicated they have

obtained confirmation from two facilities so far that O 2 - corrected TRS data were provided as requested, and that the 12

- hour O 2 averages used to correct the data to 8 percent or 10 percent , as appropriate, were reported in the “ % O 2 correction ” column. Thus, commenter 0058 concluded,

the TRS data for units 109.RB3, 109.RB4, 109.LK1, and 112.AA

- 110 have been erroneously

double

- corrected for O 2 in the EPA’s analysis.

Response: The EPA removed the double

- O 2 correction for TRS from recovery furnaces

109.RB3 and 109.RB4 and lime kilns 109.LK1 and 112.AA

- 110 identified by the commenters and used the data provided in the original submissions for these units. The EPA did not change

the O 2 corrections for other units unless they were sp ecifically identified as double

- corrected by

commenters

. However, EPA did review the TRS data sets to determine the number of CEMS

data sets for which double correction may have occurred and the potential eff ects of the double correction. We determined that double correction may have occurred ( e.g. , a 50/50 chance) in up

to seven additi onal recovery furnace CEMS data sets and seven additional lime kiln CEM S data

sets submitted by multiple companies. Upon further examination of the data sets, we determined that the impact of the potential double correction on our conclusions relative to the prop osed

emissions limits and monitori ng allowances is insignificant because th e number of exceedances

50 U.S. Environmental Protection Agency. Updated Review of the Continuous Emission Monitoring and Continuous Opacity Monitoring Data from the Pulp and Paper ICR Responses for NSPS Sources

. Memorandum to Docket ID

No. EPA

- HQ

- OAR

- 2012

- 0640. February 28, 2014.

51 U.S. Environmental Protection Agency. Review of the Continu ous Emission Monitoring and Continuous Opacity Monitoring Data from the Pulp and Paper Information Collection Request Responses Pertaining to Subpart BB

Sources . Memorandum to Docket ID No. EPA

- HQ

- OAR

- 2012

- 0640. April 5, 2013.33

of the proposed standard was similar in the original TRS ppm column and the potentially double

corrected TRS ppm column of each CEMS data sheet . Therefore, we did not burden ICR respondents with follow

- up questions on the TRS CEMS d ata, nor did we remove the 14 potentially double

- corrected data sets from the analysis.

3.1. 2 Operating Period

3.1.2

- 01 Comment: C ommenter 0055 believes that the semiannual basis for determining the monitoring allowance is more appropriate than the quarterly basis, stating that a semiannual basis for this requirement would not result in an increase in emissions, but would decrease the opportunity for reported violations. According to the commenter, this alleviates some of the burden on the industry w ithout harming the environment. The commenter stated that this approach is consistent with ICR data accumulated by the EPA and includes limitations that are achievable so long as the current SSM exemption is maintained. The commenter noted that industry ha s concerns that by removing the current SSM exemption, it would be difficult to meet the proposed 1 percent allowance.

Response: The EPA acknowledges the commenter ’s support for using a semi annual basis for

determi ning monitoring allowance and has chosen to finalize this requirement consistent with the semiannual reporting frequency in §60.288a(a). The EPA agrees the semiannual allowance

calculation basis will reduce reporting burden on the industry without harming the environment. As proposed, t he EPA is eliminating the SSM exemption for reasons discussed in section 4 of

this document.

3. 1

. 2

- 02 Comment : C ommenter 0058 stated that the EPA did not evaluate whether compliance with the proposed monitoring allowances ha d been “adequately demonstrated” under the currently proposed quarterly reporting basis or the alternative semiannual reporting basis. The

commenter concluded that achieving compliance on an annual basis is not equivalent to achieving compliance on a quarte rly or a semiannual basis. The commenter noted that a 1
percent annual monitoring allowance of the 730 TRS reporting periods in a year corresponds to

a maximum of seven reporting periods of excess emissions without triggering a violation of the standard (p rovided the applicable proposed cap is not exceeded). The commenter further noted that, w hen considered on a quarterly or semiannual basis, this corresponds to 1.8 (rounded up to 2) reporting periods per quarter or 3.6 (rounded up to 4) reporting periods s emiannual ly.

A ccording to the commenter, a facility with seven or fewer reporting periods in a year would therefore be in compliance on an annual basis , but if more than two excursions occur red in any given quarter, or more than four occur red in a semiannual period, the facility would fail to meet the requirement on either a quarterly or a semiannual basis. T he commenter stated that EPA

, therefore, cannot conclude, based on a review of annual performance data, that compliance with the proposed quart erly

- based standards has been adequately demonstrated. To illustrate his point, the commenter provided two specific examples

. 52

 In the first example, the annual average TRS from a current NSPS recovery furnace [NDCE

- WBESP] is reported as 0.75 ppm @ 8 percent O 2 (99 th percentile = 2.55 ppm @ 8 percent O 2 ) for the year 2009. In the same year, five exceedances of the 5 ppmdv limit

52 Comment 0058, p. 2.34

were reported. Data w ere available from 694 of 730 possible 12

- hour averaging periods. On an annual basis, it would appear that the data from this NSPS recovery furnace demonstrate that the proposed standards are achievable. However, even though the annual percentage of averaging periods that exceeded 5 ppmdv was less tha n 1 percent (5/694 = 0.72 percent), 4 of the 5 exceedances occurred in the third quarter

, and the fifth exceedance occurred in the following quarter. If the proposed standards were applicable to this NSPS unit, the 1 percent monitoring allowance would be e xceeded on a quarterly basis, and also on a semiannual basis.

 In the second example, another NSPS recovery furnace [NDCE

- DBESP] in the data set has an annual average TRS of 0.30 ppm @ 8 percent O 2 and a 99 th percentile of 4.44 ppm @ 8 percent O 2 . Six excee dances of the 5 ppmdv emission limit were reported (all during periods of S/S ) with data available for 726 reporting periods. The percentage of averaging periods exceeding 5 ppmdv was calculated on an annual basis to be less than 1 percent (6/726 = 0.83 pe rcent). However, all 6 exceedances occurred on four consecutive days in one quarter while trying to bring the recovery furnace back online. During this period,

BLS were fired at a reduced rate along with supplementary fossil fuel firing. As indicated

in Ta ble 1 of the comment, 3.3 percent (6/180) of averaging periods in the third quarter exceeded 5 ppmdv. The example also indicates that the 1 percent monitoring allowance would not be adequate when periods of S/S are included. Hourly production and 12

- hour

T RS data for this unit were plotted in Figure 1 of the comment.

Commenter 0058 noted that EPA’s data analysis also included some e xamples of recovery furnaces reported to be meeting the proposed 20 percent opacity limit and 2 percent monitoring

allowance on an annual basis, but unable to meet the requirements on a quarterly basis. Table 2

of the comment compare d the quarterly and annual evaluation of exceedances for an NSPS

NDCE

- DBESP recovery furnace, reported to have an annual average opacity of 13.07 perc ent excluding exceedances. 53 While the recovery furnace achi e ved the 2 percent allowance on an annual basis (at 1.33 percent), it did not ach ie ve it for the 1 st quarter of the year, with 2.24 percent of the averaging periods for the quarter exceeding 20 percent opacity. Table 3 of the

comment provide d the same comparison for another NSPS NDCE

- DBESP recovery furnace reported to have an annual average opacity of 5. 71 percent excluding exceedances. 54 Similar to the other recovery furnace, this furnace m et the 2 percent allowance on an annual basis (at 1.31 percent) , but d id not achieve it for the 3rd quarter, with opacity greater than 20 percent for 2.28 percent of th e averaging periods for that quarter

.

Commenter 0058 further noted that EPA, in its review of COMS data from recovery furnaces, ascertained that only 12 out of 160 recovery furnaces were unable to meet these limits and thereby concluded that compliance at these levels was adequately demonstrated. However, the commenter pointed out that EPA’s assessment of performance used annual performance data (as opposed to quarterly or semiannual ). The commenter also noted that 7 out of the 12 furnaces that

were unable to meet the limits were subject to NSPS, indicating that achievability is an issue for

NSPS units. The commenter recommended that EPA carry out a thorough review of NSPS unit performance using the same averaging time as proposed in the standard, in order to support the “adequately demonstrated” conclusion.

53 Id.

, Table 2.

54 Id. , Table 3.35

Commenter 0059 supported the conclusions of commenter 0058, stating that the EPA’s approach in analyzing COMS and CEMS data does not adequately support the proposed changes in monitoring allowances

. The commenter asserted that it is inappropriate to assess the ability of NSPS units to comply with a proposed quarterly pe rcent exceedance requirement using annual

exceedance data. Given that percent exceedance is a function of the total number of exceedances in the applicable “period,” the commenter argued that the use of a longer analysis period has the potential to overstate the unit’s performance and yield erroneous conclusions on the ability of

furnaces and lime kilns to meet the allowances on a quarterly basis.

Response: The EPA is finalizing a semiannual period for the monitoring allowance calculation consistent with the semiannual reporting frequency in §60.288a(a)

. In an up dated analysis of the

TRS CEMS and COMS data , the EPA repeated monitoring allowance calculations based on a semiannual reporting period instead of the annual basis used for the proposal. Details of this analys is can be found in the memorandum titled, Updated Review of the CEM S and COM

S Data from th e Pulp and Paper ICR Responses for NSPS Sources

, found in D ocket ID No. EPA

- HQ

OAR

- 2012

- 0640. We address commenter 0058’ s specific examples below.

In the first example provided by commenter 0058, an NDCE

- WBESP recovery furnace ( 226.R ECB2 ) indicated by EPA prior to proposal to have a 99 th percentile TRS concentration of 2.55 ppm and 5 exceedances for the year was reassessed by the commenter on a semiannual

basis . The commenter found that 4 of the 5 exceedances occurred in the 2 nd reporting period

, which would exceed the 1 percent allowance for that period. In EPA’s updated assessment, data

for 111 reporting periods included in the pre

- proposal assessment were removed due to “process down” or “0 production” periods . The new assessm ent showed zero exceedances in the first

semiannual reporting period and one exceedance in the second reporting period , resulting in a monitoring allowance usage of 0.3 percent (1 exceedance/ 33 1 reporting periods). This unit would be in compliance with the 5 ppm TRS limit and 1 percent monitoring allowance for both

semiannual reporting periods based on the 2009 data analyzed

.

In the second example provided by commenter 0058, an NDCE

- DBESP recovery furnace ( 180.D001) analyzed by EPA prior to proposal to have a 99 th percentile TRS concentration of 4.44 ppm and 6 exceedances for the year was reassessed by the commenter and foun d to have exceedances occurring in the 3 rd quarter, resulting in the need for a 3.3 percent monitoring

allowance. In EP A’s updated assessment based on semiannual reporting , there were zero

exceedances in the first semiannual reporting period and six in the secon d, resulting in an exceedance of 1.6 percent (6 exceedances/365 reporting periods). This unit would not be in

com pliance with the 5 ppm TRS limit and 1 percent monitoring allowance for both semiannual reporting period s of the year.

Table 2 of comment 0058 shows the commenter’s reanalysis of a n NDCE

- DBESP recovery

furnace ( 174.G

- 32 ) that EPA analyzed prior to proposal and found met a 20 percent opacity limit with a 2 percent monitoring allowance. The commenter’s assessment shows that the unit would not meet the standard if assessed on a quarterly basis. The EPA’s updated assessment, based on

semiannual reporti ng periods, show s that the unit exceeded 20 percent opacity in 2.13 percent of valid readings in the first semiannual reporting period (847/39

, 771) and by 0.59 percent in the36

second period (254/43

, 165)

. T h is unit could be out of compliance with the 20 perc ent opacity limit and 2 percent monitoring allowance for the first reporting period of the year if the enforcement authority does not round the 2.13 percent allowance down to 2 percent

.

Table 3 of comment 0058 shows the commenter’s re analysis of a n NDCE

- DBESP recovery

furnace ( 195.003 ) that EPA proposed could meet a 20 percent opacity limit with a 2 percent monitoring allowance. The commenter’s assessment shows that the unit would not meet the standard if assessed on a quarterly basis. The EPA’s upd ated assessment based on semiannual reporting and with the removal of data associated with periods of no production show s that the unit exceeded 20 percent opacity for 0.63 percent of readings in the first reporting period (173/27348) and 1.54 percent of r eadings in the second reporting period (665/43297). This unit would be in compliance with the proposed 20 percent opacity limit and 2 percent monitoring

allowance calculated on a semiannual basis

.

Table s 3 A through 3D below summarize the number of CEMS and COMS data sets analyzed for new, modified (or reconstructed), and existing recovery furnaces and lime kilns. The number of data sets in compliance with the proposed standards and monitoring allowances before proposal

and i n the final data sets is indicated. The values presented from the proposal analysis represent calculation of the monitoring allowance s on an annual basis, while the values from the final analysis reflect the revised data sets and calculation of monitoring allow ances on a semiannual basis. Use of a semiannual basis for calculating the allowance s resulted in only minor differences in the number of emission units that would not be in compliance with the proposed standards and monitoring allowances. The semiann ual allow ance calculation would change the compliance

outcome for:

 3 out of 160 recovery furnace COMS data sets,

 0 out of 29 lime kiln COMS data sets,

 2 out of 141 recovery furnace TRS data sets, and

 2 out of 110 lime kiln TRS data sets.

As shown in Table s 3 A through 3D below, EPA’s revised analysis accounts for the reason a unit became subject to the NSPS ( e.g. , new or modified [including reconstructed] ). The majority of data sets for new and modified recovery furnaces and lime kilns demonstrate compliance with the proposed standards. For opacity, the majority of the data sets for existing (non

- NSPS) recovery furnaces and lime kilns also showed compliance with the proposed 20 percent opacity limit and monitoring allowance. A number of existing (non

- NSPS) data sets also showed compliance with the proposed TRS limits and allowances. Therefore, EPA maintains that the proposed standards are adequately demonstra ted based on the final revised data sets with the proposed monitoring allowances calculated on a semiannual basis. Considering the large number of data sets analyzed for this NSPS review (including most of the emission units in the U.S.) and the prepondera nce of emission units meeting the proposed standards, we do not believe it is necessary for every single data set and emission unit analyzed to have shown compliance with the standards and monitoring allowances proposed for subpart BBa in order for EPA to conclude that the proposed standards are adequately demonstrated and achievable . Subpart BBa is not immediately applicable to the emission units analyzed, but will become applicable to emission units as they are newly installed, modified, or reconstructed in the future.37

Figures 4 through 7 depict the semiannual monitoring allowance calculations for lime kilns or recovery furnaces. The monitoring allowance represents the percent of CEMS or COMS averaging periods exceeding the applicable emission limit for e ach emission unit. Figure 4 shows that the 2 percent monitoring allowance (calculated on a semiannual basis) for recovery furnace opacity is achieved by the majority of recovery furnaces in the U.S. Figure 5 shows that a 1 percent opacity monitoring all owance (calculated on a semiannual basis) is achieved by most lime kilns with ESPs in the U.S. Figures 6 and 7 show that the majority of recovery furnaces and lime kilns subject to subpart BB achieved a 1 percent TRS monitoring allowance on a

semiannual b asis. TRS data for existing non

- NSPS (subpart BB) sources are omitted from Figures 6 and 7 because existing non

- NSPS sources are subject to TRS limits less stringent than

the current NSPS limits

.38 Table 3A. Summary of Recovery Furnace COMS Data Sets Analyzed

Unit NSPS

Classification 1 Proposal data set with monitoring allowance

calculated on an annual

basis Final data set with

monitoring allowance

calculated on an

semiannual basis Notes

No. of COMS data sets 160

New 52

Modified 32 Existing (not subject to NSPS) 76 No. of COMS meeting 20% opacity
with a 2% allowance 144 141

New 45 44

Modified 30 30 Existing (not subject to NSPS) 69 67

No. of COMS not meeting 20% opacity with a 2% allowance 16 19

New 7 8 Installation dates ranged from 1978 to 1991. The semiannual percentage of periods exceeding 20% opacity ranged from 0.59 to

8.05%. Four of the 8 units in the final data set
achieved a 4% allowance on a semiannual

basis. 2

Modified 2 2 Two stacks having separate COMS on a furnace that became subject to the NSPS in 1990. The semiannual percentage of periods exceeding 20% opacity ranged from 1.26 to

7.72%. Neither of these COMS achieved a
4% allowance. 2

Exis ting (not subject to NSPS) 7 9 5 of the 9 units in the final data set achieved a
4% allowance on a semiannual basis. 2 The semiannual percentage of periods exceeding 20% opacity ranged from 0.39 to 35.2%.

1. New and modified units are defined in terms of the subpart BB NSPS 1976 applicability date (not the more recent subpart MM applicability date). 2. See response to comment 3.2

- 01 for more discussion of the commenter

- requested 4% monitoring allowance.39 Table 3B. Summary of Lime Kiln COMS Data Sets Analy zed

Unit NSPS

Classification 1 Proposal data set with monitoring allowance

calculated on an annual

basis Final data set with

monitoring allowance

calculated on an

semiannual basis Notes

No. of COMS data sets 29

New 23

Modified 2 Existing (not subject to NSPS) 4 No. of COMS meeting 20% opacity
with a 1% allowance 27 27

New 21 21

Modified 2 2 Existing (not subject to NSPS) 4 4

No. of COMS not meeting 20% opacity with a 1% allowance 2 2

New 2 2 Exceedances of the 1% allowance were
1.84% and 2.19% on a semiannual basis.

These ESP

- controlled kilns became subject to the NSPS in 1997 and 1994, respectively (prior to establishment of the subpart MM opacity monitoring requirements).

Modified 0 0 Existing (not subject to NSPS) 0 0 1. New and modified units are defined in terms of the subpart BB NSPS 1976 applicability date (not the more recent subpart MM applicability
date).40 Table 3C. Summary of Recovery Furnace TRS CEMS Data Sets Analyzed

Unit NSPS

Classification 1 Proposal data set with monitoring allowance

calculated on an annual

basis Final data set with

monitoring allowance

calculated on an

semiannual basis Notes

No. of TRS CEMS data sets 141

New 51

Modified 28 Existing (not subject to NSPS) 62 No. of CEMS meeting 5 ppm with a
1% allowance 95 93

New 45 45

Modified 26 26 Existing (not subject to NSPS) 24 22

No. of CEMS not meeting 5 ppm
with a 1% allowance 46 48

New 6 6 Installation dates range from 1977 to 1992.

Modified 2 2 Modified in 1989 and 1990. Existing (not subject to NSPS) 38 40 Includes 33 DCE recovery furnace CEMS. The TRS emission guideline for existing DCE recovery furnaces is 20 ppm.

4 of these existing units were DCE furnaces

in the final data set that have since been replaced with or converted to NDCE technology (in 2011

- 2012 after the data were collected). 1. New and modified units are defined in terms of the subpart BB NSPS 1976 applicability date (not the more recent subpart MM applicability
date).41 Table 3D. Summary of Lime Kiln TRS CEMS Data Sets Analyzed

Unit NSPS

Classification 1 Proposal data set with monitoring allowance

calculated on an

annual basis Final data set with

monitoring allowance

calculated on an

semiannual basis Notes

No. of TRS CEMS data sets 112 110 2 data sets (for 1 new kiln and 1 existing kiln) were removed from the final analysis due to data quality issues.

New 48 47

Modified 11 11 Existing (not subject to NSPS) 53 52 No. of CEMS meeting 8 ppm with a
1% allowance 68 64

New 45 44

Modified 7 7 Existing (not subject to NSPS) 16 13

No. of CEMS not meeting 8 ppm

with a 1% allowance 44 46

New 3 3 Installed 1997, 1989, and 1994.

Modified 4 4 Modified in pre

- 1990, pre

- 1995, and 2007.

Scrubber

- controlled. Some of these kilns were up and down and had data availability issues throughout the year. Existing (not subject to NSPS) 37 39 The TRS emission guideline for existing lime kilns is 20 ppm. 1. New and modified units are defined in terms of the subpart BB NSPS 1976 applicability date (not the more recent subpart MM applicability
date).42 Figure 4

. O pacity Monitoring Allowance Data for Recovery Furnaces43 Figure 5

. O pacity Monitoring Allowance Data for Lime K ilns44

Figure 6 . TRS Monitoring Allowance Data for Recovery Furnace s Subject to the Subpart BB NSPS Limit (5 ppm)45 Figure 7 . TRS Monitoring Allowance Data for Lime Kiln s Subject to the Subpart BB NSPS Limit (8 ppm)46



### 3.2 Opacity Limits

3.2

- 01 Comment : C ommenter 0056 d oes not support EPA’s decision to propose making the opacity limit more stringent for modified recove ry furnace units under the NSPS . The

commenter noted that EPA proposes to reset the current 35 percent opacity limit to a 20 percent limit, 55 which, except for reducing the allowances percentage, is equivalent to that for new and

reconstructed units under the s ubpart MM NESHAP. The commenter argued that, a s the EPA

fo und no reason to reduce PM for modified recovery furnaces, it is not logical to reduce the opacity limit to the level for new and reconstructed units under the NESHAP either. The

commenter noted that o pacity is a continuous compliance monitoring demonstrat ion for the PM

limit

, 56 long recognized as an approximate PM surrogate . The commenter believes the EPA may have reached these opposite decisions on related parameters as a consequence of conducting the opacity COMs analyses of the ICR data separately from t he PM analyses and in part, as a consequence of the potential errors in the opacity analyses identified in previous comments

.

Commenter 0058 stated that EPA’s analysis of COMS data does not sufficiently support the decision to propose lowering the opacity limit and monitoring allowance for modified recovery

furnaces . According to the commenter, EPA’s COMS data analysis does not (a) distinguish

between new/reconstructed and modified furnaces and (b) assess the performance of modified recovery furnaces using the proposed quarterly or semiannual period. Therefore, it is unclear to
the commenter whether compliance with the proposed 20 percent opacity limit, at the 2 percent monitoring allowance level, is adequately demonstrated for modified NSPS recovery furnaces.

Commenter 0059 made similar conclusions and stated that, g iven uncertainties in the data analysis, EPA should reconsider the proposal to lower the opacity monitoring allowance to 2
percent and instead consider a higher allowance of 4 percent , cal culated on a semiannual basis,

to account for the differences between furnaces and be consistent with the reporting requirements

under subpart BB and proposed for subpart BB a. 57

C ommenter 0055 support s EPA’s decision to propos e an opacity limit of 20 percent for new, modified and reconstructed units subject to subpart BB a. The commenter believes that the 20
percent opacity requirement should be ac hievable for modified sources. According to the

commenter, t his opacity standard has been an existing requ irement in their state for over 30 years (25 PA Code §123.41) and has been achieved by the owners and operators of the affected

facilities. 58 The commenter also cited this standard as support for EPA’s decision to establish a

20 percent opacity requirement on lime kilns where an ESP control device is used. The

commenter believes that the 20 percent opacity limit proposed is practicable and achievable for

lime kilns and noted that their opinion is supported by the EPA ’ s own data.

Respons e: Our res p onses to the co mmenters’ concerns in the contex t of recovery furnaces and lime kilns are provided below.

55 S ee proposed §60.284a(d)(1)(ii)

. 56 See 78 FR 31323

. 57 S ee §60.288a(a).

58 25 PA Code §123.41: “ A person may not permit the emission into the outdoor atmosphere of visible air contaminants in such a manner that the opacity of the emission is either of the following: (1) Equal to or greater than 20 percent for a period or periods aggregating more than 3 minutes in any 1 hour. (2) Equal to or greater than 60 percent at any time. ”47

Recovery furnaces

. The subpart MM NESHAP specifies a 20 percent opacity limit for new and reconstructed recovery furnaces and a 20 percent opacity corrective action threshold for existing recovery furnaces (which includes existing recovery furnaces that are modified under NSPS definitions). In addition to the precedent for a 20 percent opacity limit under subpart MM, the EPA reviewed state pe rmits and found many recovery furnaces with state permit limits of

20 percent opacity. 59 As an example, commenter 0055 noted that a 20 percent opacity limit for recovery furnaces has been the Pennsylvania state requirement for over 30 years

.

The opacity limit under subpart BBa is part of the emission standards set forth in §60.282a. Therefore, it was reviewed independently from the PM limit. Table 3 A above summarizes the COMS data reviewed for recovery furnaces. Most of the recovery furnaces i n the U.S. were included in this analysis. Of the COMS data sets analyzed, 141 of 160 total data sets achieved the 20 percent opacity limit with a 2 percent monitoring allowance proposed for subpart BBa. In response to comments on the proposal , EPA broke the recovery furnace COMS data into new, modified, and existing sources based on the reason each recovery furnace became subject to the NSPS following the 1976 applicability date ( e.g. , new units installed after 1976, modifi cations occurring after 1976). W hile a few recovery furnaces that became subject to the NSPS when they

were installed new or were modified did not achieve the limit pro po sed for subpart BB a , we note that these units all became subject to the NSPS over 20 years ago. Recovery furnaces that have come online as new units or been upgraded over the past decade showed compliance with the proposed 20 percent opacity limit with a 2 percent monitoring allowance. The EPA is unaware of any technological reason that would hinder modified units from me eting this limit, especially considering that the majority of existing sources not subject to the NSPS already meet the proposed limit.

Although a 4 percent monitoring allowance (suggested by commenter 0059) would provide some additional flexibility, it would not resolve the issues noted for all of the new and modified NSPS

units in Table 3 A that did not meet 20 percent opacity with a 2 percent allowance. The two modified recovery furnaces that did not meet the 2 percent allowance also would not meet a

4 percent allowance. We fail to see any basis for the 4 percent allowance suggested by the

commenter.

O ur analysis of the COMS data show s that 20 percent opacity (with a 2 percent monitoring allowance calculated on a semiannual basis) has been achieved by most of the recovery furnaces

in the U.S. Based on that analysis , and given the opacity levels established under subpart MM and permit limits, we maintain that this opacity limit has been adequately demonstrated

, and we are finalizing this limit in subpart BBa.

Lime kilns

. The EPA proposed to add an opacity standard to subpart BBa for lime kilns controlled by ESPs alone ( i.e. , without a scrubber) based on the subpart MM 20 percent opacity corrective action level for new and existing lime kilns and our review of 29 COMS data sets for

27 lime kilns (including 2 kilns with separate COMS in dual stacks)

, showing that 20 percent opacity with a 1 percent monitoring allowance has been adequately demonstrated under periods

59 U.S. Environmental Protection Agency. Review of the Air Permits for Kraft Pulp Mills. Memorandum to Docket

ID No. EPA

- HQ

- OAR

- 2012

- 064. April 26, 2013.48

of normal operation and during S/S . Th e lime kiln opacity data sets were reanalyzed and broken out by NSPS applicability to address public comments on the proposed NSPS review. Based on reanalysis of the data , we maintain that 20 percent opacity an d a 1 percent monitoring allowance

has been ad equately demonstrated for lime kilns. Only two ESP

- controlled kilns that became subject to the NSPS in 1994 and 1997 as new units were unable to meet the 20 percent opacity limit with a 1 percent monitoring allowance. One of these kilns exceeded the 20 per cent opacity limit during 1.84 percent of averaging periods in one semiannual period , but ach i e ved the allowance (at 0.27 percent ) in the other semiannual period. The second kiln exceeded the 20 percent opacity limit during 2.19 percent of averaging periods in the only semiannual period for which data were provided. The remaining 25 kilns (with 27 COMS) , including existing and modified kilns, showed compliance with the proposed opacity standard and monitoring

allowance calculated on a se miannual basis. W e maintain that the 20 percent opacity limit with a 1 percent monitoring allowance calculated on a semiannual basis is adequately demonstrated to be achieved in practice because the majority of ESP

- controlled kilns achieved this standard.



### 3.3 TRS Limits

3.3

- 01 Comment : Commenter 0055 believes that adding an upper limit of 30 ppmdv @ 8
percent O 2 to the monitoring allowance for TRS for recovery furnaces tightens emissions limitations without undue burden to the industry. However, t he commen ter believes that there is an inconsistency in how the upper limit of TRS for recovery furnaces is applied. For straight kraft recovery furnaces, which have a limit of 5 ppmdv @ 8 percent O 2 , the commenter noted

that this never

- to

- exceed limit is 600 percent of the normal requirement. For cross recovery furnaces, which have a limit of 25 ppmdv @ 8 percent O 2 , the commenter noted that this never

to

- exceed limit is only 20 percent above the norm al limit. The commenter stated that i t is inappropriate to establish limits for cross recovery furnaces because there is a lack of data. The

commenter also added that data for straight recovery furnaces should not be used to establish limits for cross recovery furnaces. The commenter agreed with establishing the u pper limit of 22 ppmdv @ 10 percent O 2 for TRS emissions from lime kilns.

R esponse: The EPA agrees with commenter 0055 that the calculated upper limit for TRS from recovery furnaces (30 ppm) should be specified to be for straight recovery furnaces , and th e final rule language h as been edited for clarification. This 30 ppm upper limit was based on analysis of data for straight recovery furnaces and also coincides with the span of the TRS monitor required

in §6 0 .284 a (a)(2)(i) for straight recovery furnaces.

The cross recovery furnace TRS emission limit is higher than the straight recovery furnace TRS

emission limit for three technical reasons. First, the sulfur content of the semichemical liquor is higher than traditional kraft liquor. Second, the heat conte nt of the liquor is lower because it contains less organic material than kraft liquor due to higher pulping yields. Third, the heavier sulfur loading and the lower operating temperature puts a restriction on the amount of excess O 2 available to oxidize the sulfur compounds. If we were to base a cross recovery furnace upper limit on the straight recovery furnace data, the limit would be 150 ppmdv (600 percent x 25 ppmdv, to utilize the same ratio). This limit is unreasonable because the span of the monitors are required to be set at 50 ppmdv. Because we do not have continuous monitoring data for cross recovery furnaces to analyze (with no known cross recovery furnaces subject to NSPS at this time), we are setting the upper TRS limit for cross recovery furnace s at the instrument span of 5049

ppm dv for these units. This upper limit can be reevaluated during the next NSPS review should data become available for cross recovery furnaces in the future.



### 3. 4 Startup and Shutdown Performance Data

3.4

- 01 Comment : C ommenter 0058 stated that the EPA needs to consider performance data

under S/S conditions before proposing more stringent monitoring allowances that include S/S periods. According to the commenter, their targeted review of ICR data has identified instances

where S/S data were either excluded from data submittals or inappropriately labeled/included, which has the potential to influence EPA’s conclusions on the ability of NSPS units to comply with the proposed monitoring allowances, when also including S/S pe riods. T he commenter noted that EPA indicated in its CEMS review that 29 NSPS lime kilns were achieving the proposed 1 percent monitoring allowance o n an annual basis. The commenter stated that (1) 13 of the 29 lime kilns did not include any S/S data; (2) a mixture of blank cells and values were included for 4 kilns during periods of S/S ; and (3) 2 additional mills included comments that they are required to maintain records of startup, shutdown and/or malfunction only when an emission

standard is exceeded. In cases where shutdown data w ere included and identified in a data set, they were sometimes reported as ‘zero’ and corresponded to periods of ‘zero’ production, artificially overstating unit performance, and potentially impacting the results and conclusions.

The commenter also stated that it is inappropriate to include periods when onl y oil (or other fossil fuel) is fired during periods of S/S in the analyses because excess emissions are defined as periods when BLS are fired (for recovery furnaces). The commenter stated that they were not able to substantially comment on S/S due to insu fficient time to fully evaluate the extensive data.

In a similar comment, c ommenter 0056 stated that EPA may have inadvertently misconstrued portions of the ICR data used in the proposed rulemaking, raising concerns that EPA used impaired analyses to reac h certain conclusions that may in reality be unsupported. As an example, the commenter cited the proposal to eliminate the monitoring exemptions for excess emissions during SSM periods and instead require the normal operating emission standards to be

met a t all times. The commenter cited reports finding that the EPA based some facility demonstrations of achievability on emissions performance measured on an annual basis by evaluating the annual percentage of the excess emissions allowances, b ut when the actual regulated quarterly performance was examined, the allowance would not have been adequate and the facility would have had un

- allowed excess emissions subject to enforcement. The commenter also noted another example reporting the apparent misident ification of S/S data, or the lack thereof, in a large fraction of the 29 units that EPA analyzed in its analysis of lime kiln TRS

CEMS data; the commenter said that this analysis led EPA to a probably erroneous conclusion

that kilns could meet the emissio n standard given a 1 percent monitoring allowance even while including S/S periods

.

In another comment, c ommenter 0059 stated that t he 2011 ICR did not include data during S/S in all cases. Therefore, the commenter concluded that EPA may not have adequate ly considered all operating scenarios and data associated with S/S conditions in its analysis. Consequently, the underlying conclusions about performance during S/S conclusions are also potentially in error. Commenter 0059 referred specifically to the focused review of NSPS data by commenter 0058,50

which the commenter said identified i nstances where facilities either excluded 60 or mislabeled data collected during S/S periods. According to commenter 0059, t his exclusion of relevant data

could extend to a larger subset of evaluated sources, is a cause for concern, and has the potential to lead to wrong conclusions about S/S periods. The commenter also noted that there also is the potential for overstatement of unit performance as a result of the use of annu al data in assessing compliance with a proposed quarterly allowance. The commenter indicated that the potential

exclusion of S/S data from ICR data set s may further impact the “adequately demonstrated” conclusion associated with the monitoring allowances.

Response: The EPA analyzed the data available to the A gency collected through ICR responses. The ICR requested that S/S periods be included and labeled in the CEMS and COMS data sets.

The EPA used the data that it received to assess each unit’s performance for all operating periods, which would have included S/S periods that were not labeled as such. Approximately 75 percent of COMS data sets and 60 percent of TRS data sets EPA analyzed con tained S/S periods that were clearly labeled. Based on this review, EPA proposed to add a 1 percent monitoring

allowance for lime kiln TRS to account for process variability (including S/S ) in light of removal of the SSM exemption. Previously

, there was no monitoring allowance for lime kiln TRS.

EPA reviewed the continuous monitoring data again following proposal and has addressed

commenters’ concerns by removing all values associated with zero BLS or lime mud throughput and negative values. The EPA has also reanalyzed the data using a semiannual basis for calculation of the monitoring allowance, consistent with the final rule. Following reanalysis of the continuous monitoring data, EPA maintains that the proposed monitoring allowances have

be en adequately demonstrated. The commenter has not provided any specific information to the
contrary.

60 In many cases, state reporting requirements require facilities to exclude S/S data from periodic reports.51 

## 4 . Startup, Shutdown, and Malfunction

4.1 Periods of Startup and Shutdown

4.1

- 01 Comment : Commenter 0057 supported EPA’s decision to review the NSPS for kraft pulp mills and apply the standards continuously, including during times of SSM , which the commenter said was undoubtedly correct and well supported.

Response: We acknowledge the commenter ’s agreement with our proposal to apply the standards continuously and have decided to finalize a continuous standard, including during

times of SSM.

4.1

- 0 2 Comment : Regarding the elimination of exemptions from excess emissions monitoring during SSM perio ds, commenter 0056 requested that the EPA re

- evaluate how SSM periods will be treated, ( a ) in light of the potential data analysis errors regarding the ability of many sources to meet normal operating condition emission limits at all times, and (b ) with respect to the EPA’s legal view of SSM provisions of the CAA

. The commenter noted that EPA is proposing to eliminate the exemptions from the emission standards for S/S events as its response to the 2008 decision by the U.S. Court of Appeals for the D. C. Circuit vacating certain aspects of the emission exemption under the NESHAP rules, a decision EPA says it believes “applies equally

to section 111 rules

. ” 61 According to t he commenter

, the EPA concludes

, based on its ICR data analyses

, that “affected uni ts will be able to comply with the proposed standards at all times” including the operating parameter limits during S/S periods, and consequently did not propose a new standard for these periods separate from the operating emission standards.

C ommenter 005 6 does not believe that the Sierra Club court decision requires the EPA to set

numerical emission limits fo r S/S periods. As noted by the commenter, t he Sierra Club

decision 62 vacated the broad emission standard exemption during SSM events contained in the

40 CFR P art 63, S ubpart A

, General Provisions

, under CAA section 112. T he commenter

contend ed that EPA

, in the proposed NSPS revisions, proposes to change regulations that ha ve been in place for many years and change SSM provisions that were never challenged in court, without any justification of its authority to do so and without adequate factual analysis of the statutory criteria for standard

- setting. The commenter also cont ended that the court did not say

that the same emission limitations that the EPA has derived for normal operations must also apply during SSM events, and

, therefore

, it did not preclude the EPA from applying different standards during SSM events than stand ards that apply during normal operations. A ccording to the commenter, a pplying the same emission standards during SSM periods is not compelled by the statute or applicable case law, and the commenter said EPA has several options for setting NSPS for such p eriods, including establishing a design, equipment, work practice, or operational standard under CAA section 111(h ). The commenter also pointed out that , even under the NESHAP regulations promulgated after the Sierra Club decision, such as for the Boiler M ACT, EPA has established work practices for S/S periods rather than applying the same emission limits that are in effect during normal operating periods or even setting separate numerical emission

limits. 63

61 See 78 FR 31317

. 62 Sierra Club v. EPA , 551F.3d 1019 (D.C. Cir. 2008), cert. denied , 130 S. Ct. 1735 (2010).

63 S ee 40 CFR 63.11201(d)

.52

In a related comment, commenter 0061 believe s that the approach the EPA t oo k in its review of

the kraft p ulp m ill NSPS fail s to account adequately for emissions that occur during SSM periods. Commenter 0061’s comments on this issue are also supported by commenter 0056 and adopted by reference. Accord ing to commenter 0061, the EPA based its actions on insufficiently supported assumptions about SSM events and emissions during SSM periods. The commenter

asserted that the EPA has for decades recognized, in technology

- based standards under the CAA

and othe r statutes, that in many cases it is not feasible, using the identified technology, to achieve

the same emission limitations established for normal operations during SSM periods. According to the commenter, the EPA has not justified departing from that pra ctice in the p roposed r ule , n or has the EPA demonstrated that the amended standards it is proposing reflect the performance actually demonstrated by best

- performing existing sources. The commenter argued that a pplying the same emission standards during SSM periods is not compelled by the statute or applicable

case law and that EPA has several options for setting NSPS for such periods, including establishing a design, equipment, work practice, or operational standard under CAA section 111(h).

Another co mmenter ( 0059 ) noted that nothing fundamental has changed as it relates to the technologies available to control TRS emissions at kraft pulp mills or the ability of those technologies to mitigate or eliminate the unavoidable excess emissions during some op erational periods. Absent such new or improved technologies, the commenter said there is no basis for EPA to revise the standards to indicate that they apply at all times.

C ommenter 0059 also stated that th e proposed rule contains a number of changes that affect mills’ compliance obligations during periods of SSM . For the most part, the commenter said those changes are not the result of EPA’s assessment of developments concerning demonstrated control technology for kraft pulp mills, but rather an expressio n of EPA policy preferences that are at odds with 40 years of EPA interpretation and application of CAA section 111. Commenter 0059 stated that they are familiar with and support comments being filed on this proposed rule by

commenter 0061 , which they inco rporated by reference. Commenter 0059 also noted that they provided exte nsive comments during the MACT S ubpart S RTR related to the necessity of having provisions that address startup, shutdown, and safety

- related vent ing for pulp mill sources that they ha ve included in a ttachments to their comments.

Response: The General Provisions in 40 CFR part 60 provide that emissions in excess of the level of the applicable emission limit during periods of SSM shall not be considered a violation of the applicable emission limit unless otherwise specified in the applicable standard. See 40 CFR 60.8(c)

. The Gen eral Provisions, however, may be superseded by language in individual subparts as we are doing in subpart BBa . The EPA proposed standards in subpart BBa that apply at all times (as specified in the proposed §§60.282a(b) and 60.283a(b)) based on EPA’s view that the reasoning of the Sierra Club decision calls into question the legality of source category

specific SSM exemptions in rules promulgated pursuant to section 111 . That reasoning guided

our review of continuous monitoring data and parametric methods f or demonstrating continuous compliance with the emission standards. For the final rule the EPA is superseding §60.8(c) with revised language in §60.285a(a) of subpart BBa

. The EPA also revised the proposed wording of §§60.282a(b) and 60.283a(b) to further clarify that the standards in subpart BBa apply at all53

times as specified in the monitoring and testing sections of the rule. In the paragraphs below, we describe the analyses and considerations that support applying the standard at all times.

Prior to p roposal EPA reviewed numerous COMS and TRS CEMS data set s that included periods of SSM, and concluded the affected units would be able to comply with the proposed

standards at all times . The proposed rule specified excess emissions monitoring allowances

based on review of the COMS and CEMS data. In light of public comments questioning certain aspects of our analysis, we have reanalyzed the COMS and TRS CEMS data following proposal (as described in Section 3). The reanalysis supports our original conclusio ns in the proposal regarding the ability of sources to meet the proposed standard during both normal operations and periods of S/S. 64 The COMS and TRS CEMS data analyzed included COMS and TRS CEMS data for most of the recovery furnaces in the U.S., TRS CEMS data for most of the lime kilns in the U.S., and COMS data for most of the lime kilns using ESP control in the U.S. Thus, the best

performing units were included in the analysis.

The EPA also reviewed the incinerator temperature, ESP, and wet scrubber parametric monitoring requirements prior to proposal

. 65 The EPA proposed several provisions to help ensure the feasibility of parametric monitoring limits during S/S

. In addition to specifying a 3

- hour block averaging time for incinerator temperature monitors, the EPA proposed to define e xcess emissions as periods below the minimum temperature of 1200 ° F when TRS emissions are fired ( i.e. , periods when an incinerator is not burning TRS

, such as during wa rm

- up and cool

- down or when an alternative control device is used, would not be considered violations). To address the need for ESPs to warm to a specified temperature (typically above 20 0°F ) before full power is applied to the transformer

- rectifier set, E PA proposed to define excess emissions as ESP parameter measurements below the minimum requirements duri ng times when BLS or lime mud

is fired (as applicable) based on several responses to the ICR indicating that mills must bring

the ir ESP online before in troducing BLS or lime mud into the recovery furnace or lime kiln, respectively. The EPA also proposed language that would allow affected units to use wet scrubber liquid flow rate (or liquid supply pressure) to demonstrate compliance during periods of

S/S because pressure drop is difficult to achieve during these periods. The EPA is finalizing these provisions substantially as proposed, and

, in response to comments, is adding to the final rule a provision that will allow facilities to use only ESP secondary voltage to show co mpliance with the ESP parameter limits for combined ESP / scrubber systems during S/S because of the difficulty in achieving the secondary current or total secondary power operating limits during

S/S

. (See comment 4.1

- 09 for details).

The commenter s question the application of the Sierra Club decision to a section 111 rule. The

EPA does not claim that the Sierra Club case constrains its authority to prescribe unique standards for SSM periods or directly addresses the legality of SSM exempti ons for section 111 standards. The EPA’s view is that the reasoning of the Sierra Club decision calls into question

64 U.S. E nvironmental Protection Agency

. Updated Review of the Continuous Emission Monitoring and Continuous Opacity Monitoring Data from the Pulp and Paper ICR Responses for NSPS Sources

. Memorandum to Docket ID

No. EPA

- HQ

- OAR

- 2012

- 0640. February 28, 2014.

65 Hanks, K. and Gooden, C., RTI International. Review of Pulp and Paper Information Collection Request (ICR) Responses Pertaining to Startup and Shutdown of Subpart BB Equipment

. Memorandum to U.S. Environmental Protection Agency. March 22, 2013

.54

the legality of source category

- specific SSM exemptions in rules promulgated pursuant to section

111. The EPA h as concluded that applying the subpart BBa standards at all times is both practical and achievable. We disagree with the commenter s ’ argument regarding the Sierra Club court decision, and we have set a numerical limit applicable during S / S. W e have evaluated

whether different standa rds during S/S periods are justified, and in this case, we have concluded

different standards are not warranted for subpart BBa given the monitoring allowances and parametric monitoring provisions provided.

We believe the monitoring allowances set here re cognize that kraft pulp mills may have brief periods where production conditions occur leading to excess emissions above the emission limits

set in the standard . Comment e rs 00 56, 00 58 and 00 59 discuss ed those types of circumstances in

their comments on this proposal and the previous subpart S NESHAP RTR proposal. For example, there is a 1 percent monitoring allowance for TRS emissions above the 5 ppm limit for straight recovery furnace s and the 8 ppm limit for lime kiln s . However, the CAA requires tha t a continuous standard must be in place. Consequently, for periods covered by the TRS monitoring allowance, we set an upper limit for periods of excess emission s of 30 ppm for straight recovery

furnaces and 22 ppm for lime kilns. Regarding the suggestio n that a separate S/S standard should be considered, industry comment e rs had previously noted that production events that lead to excess emissions can occur in both normal operation and during S/S. Our analysis of the ICR

data confirmed that observation

, so consequently we chose neither to restrict the application of

this monitoring allowance to normal operation nor to set an alternative standard that applied to periods of S/S. The flexibility inherent in the monitoring allowance approach to setting a

con tinuous standard applies at all times here

. A thorough explanation of our S/S analysis is

discussed in our response s to comments 4.1

- 04 and 4.1.05

.
The commenters have not suggested any specific work practices for subpart BBa equipment that

could be used in place of the numeric limits during S/S periods, nor have the commenters provided data to show that the standards (demonstrated through continuous opacity monitoring

, TRS emissions monitoring , or parametric monitoring) cannot be met during those times

.
Although commenter 0059 suggests that there is no basis for revising the standards so they will apply at all times absent new and improved technologies, we note that changes in control technologies are not a prerequisite for EPA to update monitoring proced ures for demonstrating continuous compliance to square them with recent legal precedent or to reflect what review of monitoring data shows is achievable with current technology

. Also, commenter s 0056 and 0061 incorrectly suggest that EPA proposed to change previous NSPS, whi ch included SSM provisions. The subpart BBa proposal did not take actions regarding any previous NSPS or equipment currently permitted to be in compliance with an NSPS, including subpart BB

.
We acknowledge the s ubpart S RTR comments prov ided by commenter 0059 that pertain to startup, shutdown, and safety

- related venting for pulp mill sources . Closed

- vent collection
systems ar e discussed further in comments 4.1

- 06 and 4.1

- 07 below.

4.1

- 0 3 Comment : Commenter 0061 argued that EPA has not justified its rejection of relief from numerical emission limitations that it has provided in NSPS for d ecades. According to the commenter, f

or the past 40 years, EPA has recognized that often it is unreasonable to require sources to meet technology

- based emission standards, such as NSPS promulgated under CAA55

section 111, during SSM periods. 66 The commenter noted that the existence of such an allowance for SSM events has been an important element of court decisions

, concluding that EPA

established reasonable NSPS for particular source categories. Despite that fact, the commenter

stated that EPA proposes that the emission limitations in the revised NSPS for kraft pulp mills would be applicable at all times, even during SSM events. 67

The commenter contended tha t t here is ample precedent for EPA applying a different standard during SSM events. According to the commenter, prior to the CAA Amendments of 1977 (which

defined “emission limitation” and “emission standard” to be something that “limits the quantity,

rate , or concentration of emissions of air pollutants on a continuous basis”) and since that time, EPA has not required sources to meet NSPS emission limitations under CAA section 111 established for normal operations, during SSM events. 68 T he commenter argued that t here is nothing in the legislative history of the 1977 amendments to the CAA that suggests Congress

intended to overturn that practice. 69 Moreover, the commenter stated that court decisions both

before and after the CAA Amendments of 1977, some of whi ch the commenter cited below, have

affirmed the appropriateness of including special SSM provisions in standards issued under

section 111.

A ccording to the commenter, a n emission limitation that applies during SSM events does not

meet the requirement of CAA section 111(a) that EPA establish “standards of performance” under that section that are “achievable” with the “best” emission control technology, “taking into consideration the cost of achieving such emission reduction, and any nonair quality health a nd environmental impact and energy requirements” that has been “adequately demonstrated,” if in

fact EPA has not demonstrated that the limitation is reasonably “achievable” with available technology during S/S or malfunction events.

66 See 40 CFR 60.8(c).

67 See, e.g. , 78 FR 31 317, 31322 & 31328; proposed §§ 60.282a(b) and 60.283a(b).

68 See 40 CFR 60.8(c).

69 Congress’s insertion of the “continuous basis” language in the definition of “emission limitation” or “emission standard” in CAA section 302(k) 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); Nat iona 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 tho se which entailed temporary

reductions in emissions when weather conditions were poor.”). When it added the language in the definition of

“emission standard” about “continuous reduction,” Congress did not in any way address the question of what

emission li mitations may apply during SSM periods, nor take any issue with EPA’s established practice of exempting excess emissions during SSM events from its performance standards applicable to normal operations. In fact, the legislative history indicates Congress w as 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 th e continuous emission limitation.”).56

Commenter 0061 asserte d t hat this plain

- language reading of the applicable statutory requirements is echoed by extensive case law. The commenter said that t he courts have long recognized that a “technology based standard discards its fundamental premise when it ignores

the limi ts inherent in technology.” 70 As an example, the commenter cited Portland Cement Ass'n

v. Ruckelshaus , 486 F.2d 375, 398 (D.C. Cir. 1973), a decision reviewing standards under CAA section 111, wherein the D.C. Circuit recognized the concern that “‘start

- up’ and ‘upset’ conditions, due to plant or emission device malfunction, are an inescapable aspect of industrial

life and that allowance must be made for such factors in the standards that are promulgated.” 71
Similarly, in 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, the commenter noted that the court held that SSM provisions are “necessary to preserve the reasonableness of the standards as a
whole.” 72 The commenter also 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, wherein the court held that the CAA requirement that NSPS be “achievable” means that the standards must be capable of be ing met “under most adverse circumstances which can reasonably be expected to

recur....” 73

Commenter 0061 noted that c ourts have reached a similar conclusion when considering the analogous CWA requirements that EPA establish technology

- based effluent limitat ions based on the best available control technology. According to the commenter, i n one such case

, the 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. 74

, 75

, 76

The commenter noted EPA ’s assertion that it “is required to ensure that section 111 emissions standards are continuous,” citing the definition of “emission limitation” and “emission standard”

70 NRDC v. EPA, 859 F.2d 156, 208 (D.C. Cir. 1988)

. 71 See also Portland Cement Ass'n v. Ruckelshaus

, at 399.

72 See also Essex Chem. Corp. v. Ruckelshaus

, at 433.

73 See also National Lime Ass’n v. EPA

, at 431n.46.

74 Marat hon Oil Co. v. EPA , 564 F.2d 1253, 1273

- 74 (9 th Cir. 1977).

75 See also, e.g. , 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 limita tions, which are tied to achieving water quality standards rather than being based on available technology, and therefore need not include an upset provision)

. 76 The Weyerhaeuser Co. v. Costle decision, 590 F. 2d 1011 (D.C. Cir. 1978), which EPA cites in the proposed r ule,

78 FR 31 329, does not support EPA’s position. In that case, the court was discussing a “technology forcing” standard, rather than one, like NSPS, that is to be based on what has already been demonstrated to be achievab le. Also, 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 Weyerh aeuser Court was considering in the passage quoted by EPA, see id . Industry is not requesting that

EPA establish NSPS that can be met even during those exceedingly unusual types of events, and just because there may be certain kinds of malfunctions that EP A could not reasonably account for in the NSPS does not mean that EPA is free to ignore all types of malfunctions when it establishes the standards. Just as importantly, the Weyerhaeuser decision came long before NRDC v. EPA, 859 F.2d 156 (D.C. Cir. 1988)

, which, as 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

.57

in CAA section 302(k) and Sierra Club v. EPA , 551 F.3d at 1021. 77 Th e commenter remarked

that this s tatement fails entirely to justify EPA’s abandonment of its longstanding provisions excusing sources from complying with numerical emission limitations (but imposing operational requirements) during SSM periods. 78

Commenter 0061 noted that EPA’s argument w ith respect to the definition of “emission

limitation” and “emission standard” in CAA section 302(k) seems to be that the statement in the definition that an emission limitation is “a requirement...which limits the quantity, rate, or
concentration of emissio ns of air pollutants on a continuous basis...” means that the same limitation must apply at all times; in other words, that by describing emission limitations as applying “on a continuous basis,” Congress intended to require that processes and associated pol lution control equipment operate perfectly at all times and without variation. The commenter argued that t here is no basis for that position, and contended that there are many indications that EPA’s (new) position about the effect of the definition of “emi ssion limitation” is wrong.

The commenter pointed out that, o n its face, a “requirement” that limits emissions “on a

continuous basis” does not have to impose the same limitation at all times , n or does the form of

the limitation have to always be the same

. 79 A ccording to the commenter, a set of regulations that imposes numerical limitations on the mass or concentration of pollutants emitted during normal operations, but that also includes conditions during which those numerical limitations do not apply, sti ll represents a continuously applicable requirement. The commenter stated that the

NSPS regulations spell out the circumstances under which a kraft pulp mill affected facility would be allowed to deviate from the numerical emission limitations that apply during normal operations, and they impose requirements for the operation of the facility during SSM events and for reporting of those events. 80 The commenter remarked that i t is simply inaccurate to describe these regulations as not providing for control of emissions on a continuous basis.

According to the commenter, EPA’s attempt to give overarching significance to the phrase “on a

continuous basis” is also undercut by the language of CAA section 302(k). The commenter pointed out that s ection 302(k) define s “emission limitation” and “emission standard” to be not solely a numerical limit on the quantity, rate, or concentration of emissions of an air pollutant on

a continuous basis, but rather “a requirement... which limits” the quantity, rate, or concentration of emissions of air pollutants on a continuous basis. The commenter stated that the statute does not say that requirement must be expressed as a single, numerical, not

- to

- be

- exceeded

- at

- all

times limitation. The commenter also noted that the remainder of CAA section 302(k) provides alternatives to a specific limitation on the quantity, rate, or concentration of emissions: “any requirement relating to the operation or maintenance of a source to assure continuous emission

77 See 78 FR 31 329.

78 See 40 CFR 60.7(b)

- (c), 60.8(c), 60.11.

79 The D.C. Circuit also reached that conclusion in Sierra Club v. EPA

, acknowledging that section 302(k)’s “inclusion of [the] broad phrase” “any requirement relating to the operation or maintenance of a source to assure continuous emission reduction” in the definition of “emission standard” suggests that EPA can establish MACT
standards consistent with CAA section 112 “without necessarily continuously applying a single standard.” 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”).

80 See 40 CFR 60.2 (definition of ma lfunction), 60.7(b)

- (c), 60.8(c), 60.11.58

reduction,” and “any design, equipme nt, work practice or operational standard promulgated under” the Act (hereafter, a “work practice standard”). 81

The commenter claimed that, a s section 302(k) is constructed, the portion of section 302(k) that

mentions “continuous basis” does not even apply to work practice standards. But even if it did, the commenter argued that a requirement to, for example, use, on a continuous basis, a particular work practice to minimize emissions in no way mandates that emissions be constant as a consequence, nor that the work practice must avoid any level of emissions during startup,
shutdown

, or malfunction that is higher than during steady

- state operations. The commenter

stated that EPA and the courts have recognized on many occasions the fact that just because a

par ticular set of processes and air pollution controls are properly designed to minimize emissions does not mean that those emissions will be at the same level at all times, nor does it mean that the properly designed equipment or work practice will operate f lawlessly, free from any variation in emissions associated with, for example, startup, shutdown, or unavoidable malfunctions. 82

According to the commenter, EPA offers no explanation how the statutory definition of
“emission limitation” and “emission standard” could support or compel its insertion of language

in the proposed rule that states that the limitations apply at all times (and, according to the preamble to the proposed rule , thereby preventing reliance on the SSM provisions of the NSPS

General Provisions), when EPA contemporaneously has promulgated categorical standards imposing “emission limitations” or “emission standards” under CAA section 112 that expressly do not apply during periods of startup, shutdown, or malfunction

. 83

T he bottom line

, according to the commenter, is that an “emission limitation” can include a design, equipment, work practice, or operational standard (which would include an SSM provision, which specifies required actions during SSM events to qualify for an exemption for

otherwise

- applicable emission limitations), and the work practice standards expressed in an SSM provision apply continuously, if at all. According to the commenter, t he rhetorical arguments in the preamble to the proposed r ule notwithstanding, the longstan ding SSM provisions of EPA’s NSPS regulations ( that EPA now suggests fail to comply with the CAA because they do not
constitute “emission limitations” ) in fact fall well within the statutory definition of that term.

The commenter further argued that Sierr a Club v. EPA did not involve NSPS at all, but rather concerned an open

- ended blanket exemption from applicable category

- specific NESHAPs

contained in a generic provision in the NESHAP General Provisions. According to the commenter, the Court concluded that this blanket exemption did not attempt to reflect the emission limitations achieved by the best

- performing sources, as required by CAA section 112(d), and so did not satisfy the CAA requirement that MACT standards be “section 112

-

81 See i d

. 82 See, e.g. , Portland Cement Ass'n v. Ruckelshaus , 486 F.2d at 399 (“‘start

- up’ and ‘upset’ conditions due to plant

or emission device malfunction, is an inescapable aspect of industrial life and...allowance must be made for such

factors in the standards that are promulgated”); Sierra Club v. EPA , 551 F.3d at 1027.

83 See, e.g. , 78 FR 7138 (Jan. 31, 2013), 40 CFR 63.7500(f) and subp ar t DDDDD Table 3 (numerical emission limitations for hazardous pollutants for Industrial Boilers do not apply during S/S ; sources must follow work practices); 77 FR 9304 (Feb. 16, 2012), 40 CFR 63.10000(a) (numerical emission limitations for hazardous pollutants for Utility Boilers do not apply during S/S ; sources firing natural gas are not even subject to work practices during those periods).59

compliant” at all tim es. 84 The commenter pointed out that the Court did not say anything about standards of performance under CAA section 111 and the requirement of section 111 that those standards reflect the performance achieved by demonstrated control technologies. Even more importantly, the commenter pointed out that the decision did not concern whether EPA could apply different emission limitations, even for HAP s, during SSM events , n or did it consider whether EPA could address SSM events through work practice standards, in cluding work practices that result in different levels of emissions during SSM

. The commenter noted that EPA did not argue that the NESHAP General Provisions SSM exemption that the Court struck down

in Sierra Club was a work practice standard under CAA sec tions 112(h) or 302(k), and so that

issue was not before the Court

, 85 b ut the Sierra Club panel did imply that EPA could establish

emission standards under CAA section 112 that specify numerical emission limits during normal operations and a work practice s tandard for SSM periods, as noted above. The commenter pointed out that n o court has struck down an SSM provision in a specific NESHAP standard, of which there are many. 86

Response: We disagree with the commenter’s statement that “ EPA has not justified its rejection of relief from numerical emission limitations that it has provided in NSPS for decades. ” The EPA did not propose to take actions regarding any previous existing NSPS or equipment currently permitted to be in compliance with an existing NSPS, inc luding subpart BB . Instead, the EPA proposed a new standard (subpart BBa) fo r which the Agency analyzed continuous monitoring data and parametric methods for demonstrating continuous compliance and developed rule provisions pertaining to continuous monitor ing that encompass or address S/S periods. With such provisions, EPA concluded that outright exemption from the standards during

S/S is un necessary . The EPA also added affirmative defense provisions to address malfunctions (discussed further in Section s 4.2 and 4.3 below). We also disagree with the comment that EPA did not show that the emission standard was achievable with available technology during S/S. As discussed in the response comment 3.4

- 01, EPA analyzed the data collected through the ICR,

which contained data for S/S periods. Our analysis shows that the standard is achievable at all times, including during periods of S/S.

The EPA disagrees with the commenter who asserts the case law supports its assertion that an NSPS cannot satisfy the requi rements in CAA section 111(a)(1) if that NSPS applies at all tim es (i.e. during malfunctions). For malfunctions, the EPA recognizes that even equipment that is properly designed and maintained can sometimes fail and that such failure can cause a violation of an emission standard, but does not agree with commenters that argue that the EPA’s approach to malfunctions is flawed. As discussed in the preamble to the final rule, the relevance of the

cases such as Portland Cement and Essex Chemical Corp. are called into question in light of subsequent case law and the 1977 amendme nts to the CAA’s definition of “ emission standard” requiring that such standards be continuous. In any event, even if those cases are relevant, as also explained in the prea mble to the fina l rule, the EPA’ s overall approach to malfunction events in this rule, including the promulgation of an affirmative defense, is consistent wit h the approach
set forth in EPA’ s 1972 proposed rules cited favorably in Portland Cement in that both the

84 Sierra Club v. EPA , 551 F.3d at 1021.

85 See 551 F.3d at 1028, 1030.

86 Since the Sierra Club v. EPA decision on the NESHAP General Provisions SSM exemption, EPA has taken it upon itself to remove SSM provisions from existing NESHAPs as EPA revises them. No court has upheld such a revision to categorical NESHAPs on the merits, either.60

EPA’s ap proach 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 criticized the EPA regulati ons that contained no specific provisions to address malfunctions and the EPA‘s assertion that malfunctions would be dealt with by the informal exerc ise of discretion in the Agency’ s enforcement activities. Those decisions did not require exemptions or les s 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 d efense to civil penalties for exceedances of emission limits that are caused by

malfunctions. The court in Marathon Oil Co. v. EPA , 564 F.2d 1253, 1272 (9th Cir. 1977) held that the EPA must formalize its approach to upsets under the Clean Water Act. The a ffirmative

defense does so. See

, Mont. Sulphur & Chem. Co. v. United States EPA , 2012 U.S. App. LEXIS 1056 (5 th Cir. Jan 19, 2012) (in rejecting industry argument based on Marathon Oil that reliance on the affirmative defense was not adequate, 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 the EPA place the burden on t he permit holder of producing the relevant data and proving that the upset could not have been prevented. Id.

Regarding Sierra Club , the EPA does not claim that the Sierra Club case constrains its authority to prescribe unique standards for SSM periods or directly addresses the legality of SSM exemptions for section 111 standards. The EPA’s view is that the reasoning of the Sierra Club decision calls into question the legality of source category

- specific SSM exemptions in rules promulgated pursuant to section 111. Our concerns regarding the legality of SSM exemptions in

section 111 rule s prompted us to identify alternatives to an SSM exemption in the newly proposed subpart BBa to ensure that the standards are applied continuously (see our response to

comment 4.1

- 02 )

. The EPA disagrees with the commenter ’ s suggestion that the existence of an SSM exemption in rules implementing section 111 in 1977 when Congress enacted the

continuous basis language in the definition of emission standard is evidence that Congress approved of that regulatory SSM exemption. We do not believe the legislative history and the other evidence cited supports that Congress was aware or approved of that e xemption.

The commenters state in several different ways that they believe that the ‘continuous standard’ principle allows EPA to se t a different standard during S/S than applies during normal operation. We generally agree and, as they cite, have set different stand ards during S/S in rules ( e.g. , Boiler MACT [78 FR 7138] and Utility MACT [77 FR 9304]

. W e have evaluated whether differen t standards during S/S periods are justified for subpart BBa

, and we believe different standards are not warranted. Here, our analysis showed that the best

- performing sources could achieve a continuous emission limit that was applicable at all times if we set monitoring parameters that

allowed brief excursions above the base line limit, but set a cap on any exceedance or ensured that the source was continuously monitored in some way . By sett ing a cap on the standards

monitored with TRS CEMS , a continuous standard remains in place during the allowance

. Technically, the commenter is correct in stating that we did not set a separate baseline standard during S / S. However, we did recognize that so urces with the best

- performing control technology may briefly exceed the continuously monitored baseline emission limit from time to time,61

including during S / S periods. Thus we accommodated those circumstances, which we acknowledged as having the potential to occur during S / S, with an allowance. Again, setting a cap on the allowance sets a standard that applies continuously. Not limiting the periods that the capped exceedance was available, for example to just S / S periods , we believe adds flexibility to

the use of the capped exceedance. We also added a provision to subpart BBa that would allow enforcement authorities to consider an alternative compliance calculation that allows TRS

emissions to be uncorrected for O 2 during S/S periods because the O 2 correcti on equation could

cause an otherwise

- compliant TRS measurement to exceed the applicable concentration emission

limit when O 2 levels in the stack approach ambient conditions. For opacity monitors, we provided an opacity monitoring allowance to address exces s emissions during any times including S/S periods , and added an ESP parametric monitoring requirement to ensure the opacity standard is continuous. Furthermore, as described in response to the previous comment, we developed provisions for parametric monit ors that would allow flexibility during S/S events while ensuring the standards apply continuously ( e.g ., monitoring one of two wet scrubber or ESP parameters during S/S so that transient parameters with potential to be unachievable during

S/S are not used for enforcement during those times). W e believe that the suggestion that perhaps EPA should have developed a separate emission limit or work practice standard for S / S periods for subpart BBa would have added a n unnecessary layer of complexity t o the standard, not flexibility. For example, the Boiler MACT and Utility MACT work practices necessitated

definition s of startup and shutdown, and specification of when startup ends and “clean fuels” that could be burned during startup. These concepts have been the subject of many comments, and continue to persist as reconsideration issues. The commenters have not suggested any specific work practices that could be used in place of the numeric limits during S/S periods for subpart

BBa , nor have the commenters pr ovided data to show that the standards (demonst rated through continuous opacity monitoring , TRS emissions monitoring , or parametric monitoring) can not be met during those times.

The commenter makes several arguments regarding the definitions of “emission l imitation” and “emission standard” in CAA section 302(k) to essentially argue that EPA can provide for SSM exemptions in its NSPS by promulgating separate work practice standards that apply during SSM events, and those separate work practice standards for SSM events need include nothing more than what is currently contained in the general d uty clause in 40 CFR 60.11(d). As explained earlier, EPA agrees that it may promulgate separate standards for S/S events that, together with the standards that apply duri ng normal operations, constitute sta ndards that apply at all times. EPA also agrees that those standards

– either for normal operations or S/S events

– may be in the form of numerical emissions limits or work practice standards (assuming the requirements o f CAA section 111(h) are met). However, The EPA flatly disagrees that we can promulgate an NSPS that includes an exemption from those standards during SSM events. To promulgate such a standard would be to perpetuate another form of an SSM exemption, which means that no standard w ould apply during an SSM event. As explained above and in the preambles for both the proposed and final rules, EPA does not believe the Sierra Club decision allows for such an exemption

. 87

87 See section 5 of the proposed rule preamble ( Periods of startup, shutdown and malfunction) at 78 FR 31328

- 3 1330, May 23, 2013, and section B (Startup, Shutdown and Malfunction) in the “Summary of Significant Changes Following Proposal” section of the final rule preamble.62

As explained earlier, in the final rule we are setting standards that apply during startup and shutdown periods in response to the Sierra Club decision. We have explained in the preambles for the proposed and final rules our rationale for not setting a separate standard for S/S events for this source category. The commenter has not provided information to support development of

alternative standards that w ould apply during S/S events or offered any evidence, information or other specific argument regarding why these facilities cannot meet the standard that applies during normal operations during its S/S events given the monitoring allowances and other

flexi ble provisions included in the final rule. Therefore, EPA is promulgating the same standards that apply during normal operation for periods of startup and shutdown.

4.1

- 0 4 Comment: Commenter 0061 argued that EPA must fully justify applying the same

emissi on limitations during S/S as during normal operations

. The commenter noted that, i n the preamble to the proposed rule , EPA does not say that it is precluded from adopting different emission limitations that would apply during S/S periods. 88 The commenter po inted out that EPA has done just that in some other recent NSPS and NESHAP rulemakings. Instead, according to

the commenter , EPA asserts that because “periods of startup, normal operations and shutdown are all predictable and routine aspects of a source’s operations ” and because “in developing the proposed standards, it reviewed numerous continuous opacity and TRS monitoring data set s that included periods of startup and shutdown,” EPA concludes that “the affected units will be able to comply with the propo sed standards at all times.” 89 ( The commenter noted that EPA also proposes a provision that would allow enforcement authorities to consider an alternative compliance calculation that allows TRS emissions to be uncorrected for O 2 during S/S periods

because t he O 2 correction equation could cause an otherwise

- compliant TRS measurement to

exceed the applicable concentration emission limit when O 2 levels in the stack approach ambient

conditions. 90 )

Commenter 0061 noted that its members do not have sufficient info rmation to comment on applying the emission limitations derived for normal operations at all times, including during

SSM events. The commenter was concerned, however, that EPA does not seem to apply the same rigor in analyzing that question as it does when deriving the emission limitations for normal operations. According to the commenter, u nder CAA section 111, EPA must determine that emission limitations that are based on steady

- state operation but will apply during S/S are ”achievable” using emission reduction technology that the Administrator determines is the “best” and has been “adequately demonstrated.” The commenter contended that EPA cannot conclude that special provisions for emissions during S/S are not need ed b ased on “mere speculation.” 91

According to the commenter, i t is not app arent from the preamble to the proposed r ule that EPA

has conducted a sufficient analysis to demonstrate the achievability of the proposed emission limits during S/S events. Although EP A stated that it reviewed numerous continuous opacity and TRS monitoring data set s that included periods of S/S

, 92 the commenter was skeptical that EPA

had done a sufficient analysis, because adequate emissions data for such an analysis often are not

availa ble for periods of S/S

.

88 See 78 FR 31328 col. 2.

89 See i d . at 31 328

- 31239.

90 See i d . at 31 328.

91 See NRDC v. EPA , 859 F.2d 156, 210 (D.C. Cir. 1988).

92 See 78 FR 31328.63

According to the commenter, t here 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 demonstra ted control technology during S/S :

 To the extent emissions data come from required performance tests, the 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. 93

 To the extent EPA evaluates emissions data collected through continuous monitoring, the applicable regulations often require

, or allow

, the source to exclude from its reporting of

c ontinuous monitoring any data r eflecting SSM conditions.

 Also, atypical pollutant concentrations and other stack conditions that may exist during

S/S can result in the continuous monitoring system producing unusable data because the pollutant concentration may be outside of the monitori ng equipment’s span or the stack conditions may not meet monitoring system QA/QC parameters, or the data may be truncated on the high end because of limitations of the monitoring equipment. 94

(Conversely, the commenter noted that, once an NSPS numerical emission limitation has been established that applies during S/S , if unusual stack conditions during a S/S event are outside the QA/QC parameters for a continuous monitor that is installed and calibrated to monitor normal operations, then the source may be in violation of the NSPS because of monitor unavailability, even if the emissions during S/S , if they could have been measured adequately, would not have caused the source to exceed the average emission limitation.)

According to th e commenter, t hese factors would cause EPA to calculate an average emission

limitation that understates emissions occurring during S/S

. The commenter also pointed to a n additional problem , in that it can be unclear whether a condition that leads to excess emissions

should be characterized as a S/S event or a malfunction event. According to the commenter,

w ithout a clear demarcation (both in EPA regulations and in practice), EPA may be analyzing

data sets that exclude events that were treated as malfunctions but that EPA would say should be included in calculating average performance as S/S conditions.

While EPA sa id that it determined from continuous monitoring data that the p roposed s tandards

would be met all of the time

, 95 the commenter said it is not apparent whether or how that analysis adjusted for the limitations in monitoring data for periods of S/S described above. According to the commenter, S/S events, b y their very nature, can vary considerably in both duration and

effect on emission rate. The commenter stated that EPA would need to analyze monitoring data

for an extended period of time and for numerous facilities to try to establish emission limitations

93 See, for example, the General Provisions applicable to NSPS, which state that performance tests can only be conducted under representative conditions and which specify that: “Operations during peri ods of startup, shutdown,

and malfunction shall not constitute representative conditions for the purpose of a performance test....” 40 CF R 60.8(c).

94 Data from periods when the monitoring system is malfunctioning or being repaired is required to be excluded from emission averages under the NSPS General Provisions, 40 CFR 60.13(h).

95 S ee 78 FR 31 328, col. 2.64

that could be met during S/S (with the level of control technology provided in CAA section 1 11).

The commenter further stated that e xpressing an emission limitation as a long

- term average, while helping to address higher emissions during S/S

, could also fail to account adequately for the potential wide variation in emissions during S/S events, wh ich could be masked if EPA simply assumed that calculating a long

- term

- average emission rate from existing monitoring data

would adequately address S/S

.

According to the commenter, t here are a number of ways in which EPA could better ensure that

the stand ards applicable during S/S comply with the criteria for NSPS in CAA section 111:

 For certain types of sources and stack configurations, EPA may be able to conduct stack testing during S/S events to better delineate the variations in emissions occurring du ring

S/S (rather than extrapolating from continuous emissions or parametric monitoring).

 In a more thorough analysis, EPA may be able to analyze continuous monitoring data specific to S/S events, and at more facilities. 96

T he commenter indicated that t hese data could enable EPA to set alternative emission standards that apply during S/S , or to conclude with greater certainty that sources with the identified control technology would be able to meet emission limitations established for normal operations

d uring S/S periods, as well. The commenter suggested i t would be appropriate for EPA to defer promulgating any emission limitations that apply during periods of S/S until after EPA obtains

such data. According to the commenter, EPA also could study faciliti es’ operational logs to be sure it has chosen an averaging time for an emission standard sufficiently long that typical S/S periods would not cause an exceedance of the standard.

The commenter indicated that EPA also might determine, based on the infeasib ility of collecting representative data during S/S events, that it is necessary and appropriate to promulgate a design, equipment, work practice, or operational standard, pursuant to CAA section 111(h) and/or section 302(k), in lieu of deriving limitations on the mass or concentration of pollutants emitted during S/S . A ccording to the commenter, a s set forth in section 111(h)(2), EPA may determine
that it is “not feasible to prescribe or enforce a standard of performance” because it is not

feasible to captu re the pollutant and emit it through a particular conveyance, or because it is not practicable to measure emissions “due to technological and economic limitations.” In the case of

S/S events, the commenter said that one or both of these circumstances often will apply.

Commenter 0061 contended that EPA cannot, consistent with CAA sections 111 and 302(k), simply ignore the possibility of using some type of work practice, etc. standard during SSM events, instead of an unachievable emission limitation based on normal operations.

A ccording to the commenter, the prece ding paragraphs demonstrate that EPA had a number of
ways to approach NSPS for S/S conditions that would be consistent with the CAA. The

96 As suggested above, emissions testing or continuous monitoring during S/S will not be an option in all cases, because it may not be possible to obtain accurate sampling of exhaust gases during S/S periods of certain types of process or pollution control equipment. Stack sampling procedures may not apply or may not produce accurate results during the abnormal flow and concentration conditions prese nt during S/S periods . During some S/S events, gas streams may have to be diverted from the control device, and thus from the stack being monitored, altogether for a time. This is a particular concern where the gas streams being controlled are potentially flammable or explosive, as is the case at kraft pulp mills.65

commenter argued that the approach EPA took in the p roposed r ule

— assuming there is no problem based on only a limited analysis of the performance actually achieved

— was not
consistent with the CAA

. The commenter recommended that EPA defer establishment of any

standards under CAA section 111 for S/S periods until the Agency either can collect and analyze the necessary data or determine the appropriate work practice or operational standards to
establish “emission standa rds”

— either the same as or less stringent than those established for normal operations

— that apply duri ng S/S

.

Response: The EPA has used an extensive amount of information collected from pulp and paper

ICR responses (not “mere speculation” ) to justify applying the same emission limits during S/S as during normal operations. Again, we agree with the commenter ’ s suggestion that EPA can set alternative standards during S / S. W e have evaluated whether different standards during S/S periods are justified in this case ; we believe different standards are not warranted and did not propose them for subpar t BBa

. Prior to proposal, we analyzed continuous monitoring data and parametric methods for demonstrating continuous compliance and developed rule provisions pertaining to continuous monitoring that encompass or address S/S periods. These proposed provisio ns include:

 Monitoring allowances which specify a certain number of exceedances that will not be considered as violations, developed through review of TRS CEMS and COMS data set s that included SSM periods. 97

 A provision for enforcement authorities to consider the uncorrected TRS concentration during periods of S/S if O 2 levels in the stack approach ambient conditions where the O 2 correction equation could cause an otherwise

- compliant TRS measurement to exceed the applicable emission limit

.

 For ESP p arameter monitors, provisions that define excess emissions as ESP parameter measurements below the minimum requirements during times when BLS or lime mud is fired (as applicable)

.

 For wet scrubber parameter monitors, language that allows facilities to use wet scrubber liquid flow rate (or liquid supply pressure) to demonstrate compliance during periods of

S/S because pressure drop is difficult to achieve during these periods.

 For temperature monitors, a lengthened 3

- hour block averaging time, and provisions that acknowledge that the minimum temperature of 120 0°F is not met during periods when an incinerator is not burning TRS ( e.g ., during incinerator warm

- up and cool

- down or when an alternative control device is used).

The EPA is finalizing these provisions substantially as proposed, and

, in response to comments, is adding to the final rule a provision that will allow facilities to use only ESP secondary voltage to show compliance with the ESP parameter limits for combined ESP / scrubber systems during

S/S bec ause of the difficulty in achieving the secondary current or total secondary power operating limits during S/S. (See comment 4.1

- 09 for details).

With the above monitoring provisions that address periods of S/S , EPA concluded that alternative standards ( e. g ., work practices ) during S/S are unnecessary

. Again, we believe that

97 The TRS monitoring allowances are capped with an upper TRS ppm limit and ESP parameter monitoring is required during the times when the opacity monitoring allowance is used, resulting in standar ds that are continuously applied and monitored at all times even during times when the allowances are invoked.66

the suggestion that perhaps EPA should have developed a separate emission limit or work practice standard for S/S periods would have added an unnecessary layer of complexity to the

stan dard, not flexibility. The EPA added affirmative defense provisions to address malfunctions (discussed further in Sections 4.2 and 4.3 below).

The commenter questions our rigor and whether we “conducted a sufficient analysis to

demonstrate the achievabilit y” of the proposal. We believe we did. Two technical memos were provided at proposal to document our analysis of monitoring systems during S/S for p ulp and

p aper processes subject to subpart BBa:

 Review of the Continuous Emission Monitoring and Continuous Opacity Monitoring Data from the Pulp and Paper Information Collection Request Responses Pertaining to Subpart BB Sources. April 5, 2013 (EPA

- HQ

- OAR

- 2012

- 0640

- 025)

 Review of Pulp and Paper Information Collection Request (ICR) Responses Pertaining to

Startu p and Shutdown of Subpart BB Equipment (March 22, 2013) (EPA

- HQ

- OAR

2012

- 0640

- 039 thru 045)

The first memo has been updated following proposal to reflect additional analy sis of the CEMS

and COMS data. The revised memo, Updated Review of the Continuous Emis sion Monitoring and Continuous Opacity Monitoring Data from the Pulp and Paper ICR Responses for NSPS

Sources , is available in the docket for the final rule

.
The commenter appears to believe that sufficient information is unavailable on operations during

S SM because compliance testing is precluded during those periods and sources have the option of excluding CEMS and COMS data collected during SSM from reports to regulatory authorities. However, contrary to this assertion, we collected extensive TRS CEMS an d COMS data covering SSM periods. Actual monitoring data (not summary reports) were collected and analyzed prior to proposal. Our ICR specified that SSM periods be included in the data provided

to EPA

, so numerous data sets including these periods were ava ilable to EPA and analyzed for the proposal

. Opacity and TRS emissions occurring during periods of SSM were retained in the continuous monitoring data averages analyzed in order to evaluate whether the updated NSPS should distinguish between periods of S/S and normal operation as revised emission limits were

considered. A memorandum in the docket, Updated Review of the Continuous Emission Monitoring and Continuous Opacity Monitoring Data from the Pulp and Paper ICR Responses for NSPS Sources, document s the extensive amount of data that was received. The commenter suggests that EPA needs to analyze monitoring data for an extended period of time and for numerous facilities. The CEMS and COMS data sets EPA analyzed included an entire year of

data for most of th e pulp mill recovery furnaces and lime kilns in the U.S. W e believe this data

set was sufficient to repr esent the sources with the best

- performing technology and to support our conclusion that with the proposed monitoring allowances there is no need for a separate
standard fo r S/S periods.

The commenter suggests that “ atypical pollutant concentrations and other stack conditions that may exist during S/S can result in the continuous monitoring system producing unusable data ” in terms of monitor span, monitor QA/QC requirements, or m onitoring system malfunction or repairs. Periods of monitor QA/QC and monitor malfunction or repairs are excluded from the6 7

data set used to determine compliance, so these periods are irrelevant. 98 See §60.284a(c)(5)

- (7)

. We did not find exceedances of monitoring system span during periods of S/S to be a persistent problem in our analysis , and, at the best

- performing sources, any such exceedances would be accounted for with the monitoring allowance

. 99 There is no upper lim it on the COMS monitoring allowances because ESP parameter monitoring also applies, ensuring a continuous standard. We reviewed the highest values reported to establish the upper limits on continuously monitored

TRS emissions . W e noted a few high values th at would be considered malfunctions (subject to the affirmative defense provisions), prior to establishing the TRS upper limit caps at the highest representative values observed including periods of S/S (22 ppm for lime kilns and 30 ppm for recovery furnac es ). 100

Regarding the commenters’ concern that it may be unclear whether a condition that leads to

excess emissions should be characterized as a S/S event or a malfunction event, we note that the 40 CFR part 60 General Provisions provide s generic definitions of “startup,” “shutdown,” and “malfunction” to help facilities determine how to label their emissions data. The EPA has not included rigorous, equipment

- specific definitions of these terms in subpart BBa because defining these terms on an equi pment

- specific basis adds complexity to the rule and inevitably would
create issues where a “one

- size

- fits

- all” definition is not a good fit for the entire population of subpart BBa affected emission units. Most mills are likely to have site

- specific crite ria that they use in distinguishing S/S within the framework of the General Provisions definitions. Regarding labeling of the data set s EPA analyzed, EPA’s analysis treated periods labeled as “ S/S ” as S/S and periods labeled as “ malfunction s” as malfunctio ns, and EPA has no reason to believe that data were mislabeled. Even if data were mislabeled (or not labeled at all), it would have little effect on the outcome of our analysis because all SSM periods were retained in the CEMS and

COMS data set s analyzed w hether labeled or not . See also our response to comment 3.4

- 01.

For emission units where compliance is based on stack testing and continuous parameter monitoring (as opposed to continuous emissions monitoring), the EPA collected ICR responses to equipment

- specific questions seeking information on parameter limits that may be difficult to meet during periods of S/S. These responses wer e analyzed and used to design the continuous parameter monitoring provisions listed above to address periods of S/S.

When stack tests are the sole means of directly measuring emissions ( i.e. , when continuous emissions monitors are not used), we recognize the commenter’s point that emissions data are not available for SSM periods because performance testing is not conducted du ring periods of SSM. Subpart BBa does not require stack testing during periods of SSM, and in fact, through incorporation of the § 60.8 (c) language as superseded by § 60.285a(a)

, prevents stack testing during SSM.

The commenter makes three additional suggestions. First, it is suggested that EPA conduct stack testing during S/S rather than extrapolate from continuous emissions or parametric monitoring. We disagree that stack testing during S/S is necessary or appropr iate because subpart BBa does

98 See §60.284a(c)(5 )

- (7).

99 Our response to comment 5.3

- 03 further addresses our position with respect to use of values above the instrument

sp an for compliance determination.

100 U.S. Environmental Protection Agency. Updated Review of the Continuous Emission Monitoring and Continuous Opacity Monitoring Data from the Pulp and Paper ICR Responses for NSPS Sources. February 28, 201468

not require (and in fact precludes) stack testing during S/S. Continuous compliance with subpart

BB a (including periods of S/S) is determined based on continuous monitoring of emissions or
parameters.

Second, it is suggested t hat operational logs be studied closer. We believe our analyses of the

CEM S /COM S data and ICR responses to SSM questions related to parametric monitoring are sufficient in that regard. The ICR provided information on S/S times that EPA took into account

wh en establishing the 12

- hour block averaging times for ESP and scrubber parameters, and the temperature monitoring provisions. The proposal requested additional data, but none were received for EPA to analyze further. 101

Third, it is suggested that it might be appropriate for EPA to “promulgate a design, equipment, work practice, or operational standard .” As mentioned above, we did not “ignore the possibility of using some type of work practice” as the commenter insinuates. Instead, we built flexibility

into the monitoring provisions to accommodate S/S periods. The EPA requested information in the ICR on work practices that could apply during S/S, but received no useful information. The

ICR responses did provide CEMS and COMS data and valuable information on t he duration of S/S periods and their effects on operating parameters. This information was used in constructing monitoring requirements that encompass S/S periods for sources using the best

- performing control technologies.

4 .1

- 0 5 Comment: Commenter 0059 ar gued that EPA wa s not justified in reversing longstanding practice and current NSPS regulations by e liminating the exemption for SSM events meeting

certain criteria

. According to the commenter, EPA has recognized, f or the past 40 years, that

often it is unreasonable to require sources to meet technology

- based emission standards, such as NSPS promulgated under CAA section 111, during SSM periods. Accordingly, the commenter noted, 40 CFR 60.8(c) provides that “emissions in excess of the level of the applica ble emission limit during periods of startup, shutdown, and malfunction [shall not] be considered a violation of the applicable emission limit unless otherwise specified in the applicable standard.” The commenter pointed out that o ther provisions require f acilities to keep records of the occurrence and duration of any SSM event and to report to EPA a bout periods of excess emissions that occur during SSM events (or that no excess emissions occurred). 102 As noted by the commenter,

w hen EPA promulgated the emiss ion limitations currently contained in subpart BB , it was with the understanding that those emissions limitations would not apply during periods that qualified as SSM, as defined in 40 CFR 60.2.

The commenter further noted that the proposed rule includes nothing explicitly stating that the

above

- cited regulations in the General Provisions would not apply to subpart BB a. T he

commenter remarked that t his apparently is what EPA intend ed to accomplish, however, by

addin g language, in proposed §§ 60.282a(b) and 60.283a(b), that stated : “The standards in this

101 See 78 FR 31328. “ The EPA solicits comment on whether the proposal to apply these standards at all times is practicable and achievable. In particular, the EPA notes that the General Provisions in part 60 require facilities to keep records of the occurren ce and duration of any startup, shutdown or malfunction (40 CFR 60.7(b)) and either report to the EPA any period of excess emissions that occurs during periods of startup, shutdown or malfunction (40 CFR 60.7(c)(2)) or report that no excess emissions occur red (40 CFR 60.7(c)(4)). In light of this requirement, comments that contend that sources cannot meet the proposed standard during startup and shutdown periods should include data and other specifics supporting this claim.”

102 See 40 CFR 60.7(b), (c)(2), (c )(4).69

section apply at all times.” 103 Th e commenter argued that th is proposed action is not only unclear, but is also directly contrary to past EPA interpretations of the statute and of the operative facts.

C ommente r 0059 noted that C AA section 111(a) requires that NSPS be “achievable” with the

“best” emission control technology,” taking into consideration the cost of achieving such

emission reduction, and any non

- air quality health and environmental impact and energ y requirements,” that has been “adequately demonstrated.” According to the commenter, NSPS

that will cause facilities to be in noncompliance, due to unavoidable variation in emissions

associated with SSM , do not meet those statutory criteria. The commenter stated that the courts have been explicit about this. As an example, the commenter cited Portland Cement Ass'n v.

Ruckelshaus , 486 F.2d 375, 398 (D.C. Cir. 1973), a decision reviewing standards under CAA section 111, wherein the D.C. Circuit recognized th e concern that “‘start

- up’ and ‘upset’ conditions, due to plant or emission device malfunction, are an inescapable a spect of industrial

life and that allowance must be made for such factors in the standards that are promulgated.” 104
Similarly, in 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, the commenter noted that the court held that SSM provisions are “necessary to preserve the reasonableness of the standards as a
whole.” 105 The commenter also 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, wherein

the court held that the CAA requirement that NSPS be “achievable” means that the standards must be capable of being met “under most adverse circumstances which can reasonably be expected to recur ....” 106 The commenter was not aware of a si ngle court decision that reached a different conclusion with respect to NSPS. Thus, the commenter con tended that EPA’s proposal to simply delete long

- standing provisions accommodating excess emissions during SSM events

is directly contrary to judicial precedent.

C ommenter 0059 referred to EPA ’s suggest ion that it is appropriate to remove the 40 CFR 60.8( c) SSM exemption from applicability to subpart BB a because the statutory definition of “emission limitation” and “emission standard” specifies a requirement that limits air pollutant
emissions “on a continuous basis.” The commenter indicated the re are mult iple problems with

that argument:

 The qualifier that an emission limitation must apply on a continuous basis was adopted to preclude the use of intermittent or temporary controls ( e.g. , controls that operate only during “dirty air” periods), and nothing in the legislative history suggests that Congress intended to overturn existing EPA regulations that recognize the need for relief from

otherwise

- applicable emission standards during SSM events. 107

 The “continuous basis” language was inserted into the definiti on of “emission limitation” in 1977, before the D.C. Circuit’s 1980 National Lime Ass’n decision affirming the need

103 See 78 FR 31 328

- 29.

104 See also id . at 399.

105 See i d . at 433.

106 See i d . at 431 n.46.

107 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, 172; S. Rep. No. 94

- 717 (March 29, 1976) at 78.70

for NSPS to be achievable even during anticipated SSM events. It also was followed by 30 years of EPA promulgating NSPS that incorporated th e SSM exemption in 40 CFR 60.8(c) and other SSM provisions.

 The court decision EPA cite d on the “continuous” issue, Sierra Club v. EPA , 551 F.3d 1019, 1021, did not say anything about standards of performance under CAA section 111 and the requirement of se ction 111 that those standards reflect the performance achieved by demonstrated control technologies. Rather, that decision addressed what the Court concluded was a requirement of section 112 that MACT standards be “section 112

- compliant” at all times. 108 Mo reover, the Sierra Club decision interpreted the definition of “emissions standard” in CAA section 302(k) not to require “unchanging” standards and to allow EPA to promulgate MACT standards “without necessarily continuously applying a single standard.” 109

 Th e definition of “emission standard” in CAA section 302(k) does not in any way suggest that the requirement that standards limit emissions of air pollutants on a continuous basis means that the standard must be the same at all times. Moreover, section 302(k ) specifically recognizes that this requirement can be met through “any requirement relating to the operation or maintenance of a source to ensure continuous emission reduction” or “any design, equipment, work practice or operational standard promulgated

u nder” the CAA (hereafter, “work practices”). The current kraft pulp mill NSPS conform to this definition: Although the numerical emission limitations that apply during normal operations do not apply during incidents that meet the definition of SSM, pursuan t to 40

CFR 60.8(c), there are requirements related to the operation and maintenance of the source or work practices that do apply during SSM events. 110

C ommenter 0059 referred to EPA’s conclusion , which applies only to S/S, that affected facilities

can in fact meet the emission standards during S/S. For the reasons set forth elsewhere in their

current comment and in their previously submitted comments ( included in a ttachments to their

current comment )

, the commenter argued that this conclusion is not factually accurate, and indicated that, in fact

, short

- term venting of gas streams controlled under the NSPS will be unavoidable during some S/S events. According to the commenter, EPA has recognized that it

could set alternative emissio n standards for S/S periods, however, if needed to make the NSPS consistent with the performance achieved by demonstrated control technology. 111 The

commenter argued that EPA is inaccurate in it s assumption that mills can meet the numerical and

other emissio n limitations in the proposed subpart BB a standards at all times during S/S, and

, therefore , the commenter concluded that EPA wa s not justified in eliminating the 40 CFR 60.8(c) provision for excess emissions during S/S.

Response: As discussed in response to comment 4.1

- 02, 40 CFR 60.8(c) of the NSPS General

Provisions provides that emissions in excess of the level of the applicable emission limit during

108 See i d

. 109 551 F.3d at 1021, 1027.

110 See, e.g. , 40 CFR 60.11(d) (operator “shall, to the extent practicable, maintain and operate any affected facility including associated air pollution control equipment in a manner consistent with good air pollution control practice for minimizing emissions,” at “all times, including periods of startup, shutdown, and malfunction”).

111 See 78 FR 31 328; see also, e.g. , 77 FR 52554, 52558 (August 29, 2012) (same conclusion with respect to NSPS for gas turbines); 75 FR 54970, 54991 (September 9, 2010) (establishing different stan dards to apply to cement plants during S/S).71

periods of SSM shall not be considered a violation of the applicable emission limi t unless otherwise specified in the applicable standard. The General Provisions, however, may be amended for individual subparts. The EPA is finalizing standards in subpart BBa that apply at all times ( as specified in §§60.282a(b) and 60.283a(b)) based on EPA’s view that the reasoning of

the Sierra Club decision calls into question the legality of source category

- specific SSM exemptions in rules promulgated pursuant to section 111, and following review of continuous monitoring data and parametric methods fo r demonstrating continuous compliance with the

emission standards. We evaluated whether different standards during S/S periods are justified,

and

, in this case, we concluded different standards are not warranted for subpart BBa given the monitoring allowan ces and parametric monitoring provisions provided. For periods of

malfu nction, which are addressed in S ection 4.2 and 4.3 of this document, we set a standard for

affirmative defense. 112

The commenter cites several historical facts regarding the development of NSPS, including the subpart BB NSPS and the development of its SSM standard. First, we did not perform a source

category specific evaluation to support a separate standard for period s of SSM either in the 1978

standard or in the 1986 review of subpart BB . Consequently, there is no historical basis for the comparison the commenter attempts to make.

Following review of this comment and other comments related to SSM, we recognize that

ap plicability of certain sections of the General Provisions should be clarified. We offer the following clarifications :

 The definitions of startup

, shutdown , and malfunction in §60.2 apply to subpart BBa.

 The requirement to maintain records of SSM periods an d periods when CMS are inoperative under §60.7(b) applies to subpart BBa.

 The requirements under § 60.7(c) (2) to identify in the excess emissions report each period of excess emissions that occurs during SSM, and the nature of any malfunction apply to subpa rt BBa

. 113

 Inclusion of S/S in the summary report format provided in §60.7(d) applies for subpart

BBa.

 The §60.11(c) exemption from the opacity standards during SSM is superseded for
subpart BBa by §60.282a(c).

 The §60.11(d) requirement to use good air pollution control practices at all times

includ ing SSM applies to subpart BBa.

In addition, in the final rule, we have explicitly clarified the relationship between §60.8(c), the §§60.284a(d) and (e) excess emissions definitions and allowances, and §§ 60.28 2a(b) and 60.283a(b) which state that the standards apply at all times

. We changed §§ 60.282a(b) and 60.283a(b) to state that the standards apply at all times as specified in §§60.284a and 60.285a (the monitoring and testing provisions). We added a statemen t to § 60.285a(a) that §60.8 (c) shall

be read as :

112 See 78 FR 31328.

113 Note that sections within subpart BBa in addition to §60.7(c)(2) also pertain to malfunction recordkeeping and reporting.72

“ Performance tests shall be conducted under such conditions as the Administrator shall specify to the plant operator based on representative performance of the affected facility. The owner or operator shall make available to the Administrator such records as may be necessary to determine the conditions of the performance tests. Operations during periods

of startup, shutdown, and malfunction shall not constitute representative conditions f or the purpose of a performance test. ”

The SSM exemption phrase “ nor shall emissions in excess of the level of the applicable emission limit during periods of startup, shutdown, and malfunction be considered a violation of the applicable emission limit unless otherwise specified in the applicable standard ” has been

e l i m inated from the revised wording of §60.8(c) incorporated into §60.285a(a) of subpart BBa.

Section §60.285a(a) in subpart BBa now supersedes §60.8(c).

The commenter cites several co urt rulings and claims t hat our removal of the SSM exemption is inconsistent with those rulings which the commenter considers to compel EPA to recognize and address SSM periods. We believe that we have built provisions into subpart BBa that address SSM and render subpart BBa consistent with the court rulings cited by the commenter. As noted elsewhere in this section, emissions testing during SSM is not required (and in fact is prohibited), monitoring provisions are used to demonstrate continuous compliance, and these monitori ng provisions ( along with their associated definitions of excess emissions and allowances ) have been reviewed and developed

, giving special consideration to their achievability during SSM periods. For example, c ontinuous compliance is demonstrated th r ough:

 TRS monitoring provisions that contain a monitoring allowance with an upper limit cap based on S/S periods;

 Wet scrubber liquor flow rate monitoring only during S/S, not pressure drop monitoring, because pressure drop varies considerably over the S/S time frame ; and

 ESP secondary voltage monitoring only during S/S, not ESP secondary current or total secondary power because these parameters are expected to vary conside rably over the S/S

timeframe.

Other examples of flexibility built into subpart BBa to acco mmodate SSM, such as the ability to

consider TRS emissions uncorrected for O 2 when O 2 reaches ambient levels, are discussed throughout this section in other comment

- responses. Thus, we believe we have considered SSM thoroughly and reasonably in the constru ction of subpart BBa and that this new subpart is

consistent with the rulings cited by the commenter.

Regarding the commenter’s interpretation of the CAA terms “emission limitation” and “emission

standard

, ” EPA disagrees with the suggestion that the existence of an SSM exemption in rules implementing section 111 in 1977 when Congress enacted the continuous basis language in the

definition of emission standard is evidence that Congress approved of that regula tory SSM exemption.

We acknowledge the commenter’s prior and current comments related to the unavoidable short

term venting of pulping closed

- vent gas streams during S/S events for safety reasons. This topic is addressed in response s to comments below.73

4.1

- 0 6 Comment: Commenter 0059 noted that EPA added language at §§ 60.282a(b) and 60.283a(b) that states “the standards in this section apply at all times.” The commenter argued

that i t is not feasible to comply with the standards at all times. To provide context, the commenter noted the following:

 The TRS emission standard that applies to affected digester systems, BSW systems, multiple

- effect evaporator systems, or condensate stripper systems is (a) 5 ppm TRS or (b) combustion in a lime kiln, recovery fu rnace, boiler, or incinerator. Exhaust gases from these systems are collected and conveyed to a combustion device in order to meet the

standard.

 The current NSPS subpart BB states that excess emissions occur when there is a period in

excess of 5 minutes where these gases are not combusted at a temperature of at least

1200°F. 114

 Excess emissions that occur during periods of SSM are recorded and reported according

to 40 CFR 60.7.

 These systems are also subject to MACT standards at 40 CFR part 63, s ubpart S. Subpart S allows periods of excess emissions up to 1 percent of the time for LVHC pulp mill gas collection systems ( e.g. , digester, evaporator, and stripper off

- gases) and up to 4 percent of the time for HVLC gas collection systems ( e.g. , BSW gases), inclu ding periods of

SSM.

Commenter 0059 noted that t he proposed subpart BB a is more stringent than either MACT

s ubpart S or NSPS subpart BB , as EPA has added language to subpart BBa that states the standards apply at all times, and changed the definition of e xcess emissions as all 3

- hour block

averages during which the combustion temperature is less than 1200°F. 115 The commenter noted

that the re are no provisions in this standard specifically addressing short periods of safety

- related venting. According to the c ommenter, b est available technology includes unavoidable periods

wherein all vent gases cannot be routed to the control device for safety reasons and/or when the control device is inoperable or necessarily operating at a reduced rate due to a malfunction. The commenter noted that they provided m ore detail in previously submitted comments , which they

included in attachments to their current comment.

Commenter 0059 requested that EPA add the words “, as provided in §§ 60.284a and 60.285a.” to
the end of the statements in proposed §§ 60.282a(b) and 60.283a(b) that say “The standards in this section apply at all times.” Th e commenter stated that th is change is necessary to avoid

confusion about EPA’s intent in adding these short, unqualified statement s to the sections describing the PM and TRS standards. The commenter stated that it may be obvious that the monitoring and performance testing sections that follow, including provisions defining excess emissions, govern implementation of the emission limit ations, but the wording in proposed §§ 60.282a(b) and 60.283a(b) might be misinterpreted. ( As an example, the commenter noted that § 60.283a as proposed might be misunderstood to impose TRS limitations on recovery furnace emissions even during periods when B LS are not being fired.)

114 S ee §60.284(d)(3).

115 See § 60.284a(d)(3).74

Response: We acknowledge the comments on s ubpart S provided previously and attached by commenter 0059 that pertain to startup, shutdown, and safety

- related venting for pulp mill

sources

. We also acknowledge that there are overlapp ing requirements in subpart S and subpart

BBa for digester systems, BSW systems, multiple

- effect evaporator systems, and condensate stripper systems. Vent gases from these systems are collected in LVHC or HVLC collection
systems meeting the closed

- vent collection system standards in §63. 450 of subpart S. The

closed

- vent collection system standards in subpart S were promulgated in 1998 and work in

tandem with the NSPS requirements to ensure and document that pulping vent ga ses are routed through a closed

- vent collection system to the control device. In response to this com ment and

comment 2.3

- 02 on the proposed subpart BBa

, and in order to promote consistency between subpart S vent gas standards and the subpart BBa TRS standards (which use the same collection and incineration systems), we have added a re ference to the subpart S closed

- vent collection system standards in the subpart BBa standards in §§60.283a(a )(1 )(i)

- (iii) and (v)

. We have also

added definitions and criteria related to closed

- v ent collection systems to § 60.281a and §§ 60.284a(d) and (e) to ensure the standards are implemented consistently. Furthermore, as stated in response to the comment above, we have clarified the language in §§60.282a(b) and 60.283a(b) by adding the p hrase “as specified in § §60.284a and 60.285a ” to ensure that §§60.282a(b) and 60.283a(b) are not misinterpreted as being inconsistent with the monitoring and performance testing sections in subpart BBa.

4.1

- 0 7 Comment: Commenter 0059 recommended that EPA a dopt the excess emissions

p rovisions in MACT s ubpart S for d igesters, BSWs

, e vaporators, and s trippers c overed by NSPS subpart BB a . According to the commenter, t he excess emission provisions in the MACT s ubpart S regulations 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 p artially controlled pulping process vent gases. 116 The commenter cited the following text from the preamble to the final s ubpart S rule:

“EPA established appropriate excess emission provisions to approximate the level of backup control that exists at the be st

- performing mills and the associated period of time during which no control device is available.” 117

After “an analysis of the public comments and the available data regarding excess emissions and the level of backup control in the industry,” EPA determin ed 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 ba lancing problems and unpredictable pressure changes inherent in HVLC control systems.” 118

116 See 63 FR 18504, 18529 (April 15, 1998).

117 See i d

. 118 See i d

.75

“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

consid ered startup, shutdown, or malfunction under the Part 63 General Provisions....” 119

Commenter 0059 pointed out that EPA adopted the excess emission provisions after reviewing

extensive data from continuous monitoring systems and considering industry comments that

, although some mills had backup combustion devices as part of their LVHC control system, venting of NCG s is an essential safety practice (because of their explosion hazard) 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 was unavoidable for process and other reasons. 120 For HVLC
systems, the commenter noted that few m ills 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 cost

- effective due to the low concentration

of pollutants in the large gas stream. 121

In short, the commenter stated that the MACT determinations that EPA made when promulgating the s ubpart S emission standards correctly concluded that best available technology includes unavoidable periods wherein all vent gases cann ot be routed to the control device, and/or when the control device is inoperable or necessarily operating at a reduced rate.

The commenter noted that the s ubpart S emission standards (including the excess emission provisions) were designed to reflect the p erformance of the MACT technology and the actual performance of the “best

- performing” mills. The commenter indicated the re have been no technology developments for new/modified sources that would change the conclusions reached

under s ubpart S. Without any excess emission provisions, the commenter said that subpart BB a emissions standards would impose limitations not achieved even by the “best performers” and

not demonstrated as achievable at any facility.

Commenter 0059 noted that p rovisions 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. A ccording to the commenter,

a s the technology for the collection and treatment of HAPs under s ubpart S has not changed,

neither has the capability for mills to operate without needing these provisions. T he commenter

insisted that t hese provisions are necessary due to process variability and not fo r situations

defined as SSM . T he commenter said that t hese events generally are not due to situations where

119 See 63 FR 18530

. 120 See, e.g. , U.S. Environmental Protection Agency, Pulp, Paper and Paperboard Industry

– Background Information for Promulgated Air Emission Standards

– Final EIS

, Publication No. EPA

- 453/R

- 93

- 050b

, October 1997 (“BID”) at pp. 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 “pre dictably” 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 0 . MACT

- 173

- 74.

121 See 63 FR 18529; BID at pp. 4

- 81 to 4

- 82; AF&PA April 18, 1994 comments at p. 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 p. MACT

- 174 (backup combustion devices for HVLC systems could be an additional

cost of $1 billion)

.76

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 situa tion that requires a release.

Regarding LVHC systems, commenter 0059 noted that LVHC NCG gases ( e.g. , those from digesters and evaporators) are potentially explosive and cannot be burned saf ely without supplemental fuel. The commenter noted that m ost mill s have both a primary and back

- up control device 122 for the treatment of LVHC gases. T he commenter stated that t hese gases must be incinerated with support fuel and be interlocked to failsafe on loss of support fuel, combustion air, and/or boiler load. The c ommenter noted that 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, the commenter said 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. The commenter pointed out that the se conditions are required for both safety an d protection of process equipment. The commenter
noted that safety interlocks are required by both Factory Mutual Insurance and the National Fire Protection Association for burning of these NCG s. Also, when these gases are burned in a recovery furnace, the commenter indicated there are safety guidelines issued by BLRBAC.

Regarding HVLC systems, commenter 0059 noted that t he HVLC system (used to collect gases

from sources such as BSWs ) is similar to the LVHC system in causes of venting events : “The

best

- pe rforming 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

. ” 123 According to the commenter, t he main difference is that most HVLC systems do not have back

- up control devices. Therefore, the commenter noted, when boiler/firing permissives prevent the incineration of these gases, the mill must decide if emissions will be best minimized by waiting for the c ontrol device to become available or shutting down the HVLC sources.

Regarding TRS emissions d uring s tartup, s hutdown, and s afety v enting , commenter 0059 noted that, f or each type of release, it is not possible to estimate emissions on a site

- or event

- specific

basis. According to the commenter, e missions will vary based on the cause, location, and source

of the release. The commenter pointed out that e missions will vary not only between mills and

sources but between the same sources at the same mill und er different circumstances.

C ommenter 0059 noted that commenter 0058 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 , but noted that that s ite

- specific data cannot be collected for the releases

listed above , because the events cannot be anticipated, the events are typically short in duration, and it is unsafe to perform sampling. Therefore, the commenter concluded it is not possible to

develo p or suggest a TRS standard that might apply during these periods.

122 Common control devices for LVHC gases include power boilers, lime kilns, stand

- alone incinerators, and recovery furnaces.

123 See 63 FR 18529 (April 15, 1998)

.77

Commenter 0059 noted that, f or s ubpart S, EPA decided to develop MACT “floors” on a unit ( i.e. , system) basis.” 124 The commenter asserted that d evelopment of a numerical emissions

standard (other than tracking vent time) is not feasible due to limitations in technology. The

commenter indicated that there are no data available to quantify site

- specific emissions from the

vents of LVHC and HVLC systems.

Regarding p rocedures to m inimize TRS e m issions d uring startup, s hutdown, and s afety v enting

, commenter 0059 noted that, u nder s ubpart S, mill s were required to develop SSM p lans, and

stated that the same procedures are followed for sources subject to NSPS subpart BB

, even though SSM plans are n ot required. The commenter indicated that m ills use these plans and standard operating procedures to define the work practices mills must follow to minimize emissions during a release. As an example, the commenter noted that during extended steam stripper downtimes (that exceed the buffering capacity of the condensate collection tank), many facilities route their condensates to the secondary wastewater treatment system. According to the commenter, d epending on process and system design, mills also monitor the location and duration of releases from NCG systems by detecting changes in pressure (most popular), valve position, temperature at the vent location, or flow meters. The commenter noted that f acilities have instituted standard operating procedures and corrective actions to minimize these intermittent venting periods and record this information either electronically or in log books and report events, causes, and corrective actions.

Response: As stated previously, t he closed

- vent collection system standards in subpart S were promulgated in 1998 and work in tandem with the NSPS requirements to ensure and document that pulping vent ga ses are routed through a closed

- vent collection system to the control device.

In order to ensure consistency between the subpart S vent gas standards and the subpart BBa TRS standards (which use the same collection and incineration systems), we have added a reference to the subpart S closed

- vent collection system standards in the subpart BBa standard s in §§60.283a(a)(1)(i)

- (iii) and (v) . We have also added definitions and criteria related to closed

vent collection systems to §60.281a and §§60.284a(d) and (e) to ensure the standards are implemented consistently.

While we appreciate the overview of the subpart S MACT determinations provided by the commenter, we are not responding in detail to this discussion because it is outside the scope of the subpart BBa rulemaking. The preamble to the final subpart BBa rule discusses the timing of

future actions related to the industry’s subpart S petition for reconsideration of the final subpart S RTR rule relating to safety

- related venting of pulp mill vent gases

.

4.1

- 08 Comment: Commenter 0055 agree d with the EPA ’ s approach to define excess emissions as ESP par ameter measurements below the minimum requirements during times when BLS or lime mud is fired. The commenter also believes the use of wet scrubber liquid flow rate (or liquid supply pressure) by the affected units to demonstrate compliance during periods o f S/S to be reasonable. In addition, it is the commenter’s understanding that, due to the requirements of 40 CFR 60.7(b), (c)(2), and (c)(4), these exceedances were already required to be reported and, in conjunction with the monitoring allowances, are not considered violations unless they exceed the

124 U.S. Environmental Protection Agency. Pulp, Paper, and Paperboard Industry

— Background Information for Promulgated Air Emission Standards: Manufacturing Processes at Kraft, Sulfite, Soda, Semi

- Chemical, Mechanical, and Secondary and Non

- wood Fiber Mills. Publication No. EPA

- 453/R

- 93

- 050b

. October 1997. p

. 4

- 6.78

proposed upper limits. Therefore, the commenter stated, compliance is practicable and

achievable.

Response: We appreciate the support. We are promulgating our approach to define excess emissions as ESP parameter measurements below the minimum requirements during times when

BLS or lime mud is fired as proposed. We are also promulgating the use of only wet scrubber liquid flow rate (or liquid supply pressure) to demonstrate c ompliance during periods of S/S as proposed

. Similarly, as discussed in comment 4.1

- 09 below, we are promulgating a provision that requires only the use of ESP secondary voltage (as opposed to both ESP secondary voltage and current, or total secondary powe r) to be included in the compliance demonstration during periods of S/S

.
The commenter is correct that the recordkeeping and reporting requirements of 40 CFR 60.7(b), ( c)(2), and (c)(4) apply.

4.1

- 09 Comment: Commenter 0059 supported the following provisi ons from the proposed rule and believes they are necessary:

 EPA did not propose alternate standards during periods of S/S , but instead proposed some adjustments and clarifications to accommodate S/S periods for incinerators, recovery furnaces, and lime kilns.

 EPA clarified that the TRS limits for recovery furnaces and lime kilns only apply when

BLS or lime mud is being fired.

 EPA has also allowed the use of uncorrected TRS concentrations during S/S w hen the O 2 concentration is greater than 15 percent.

 B ecause incineration devices must warm to 1200 ° F during control startup prior to firing TRS gases (and subsequently cool to below 1200 ° F during control shutdown), the EPA proposed to allow facilities to omit 5

- minute recorded temperature measurements from

the 3

- hour block averages when no TRS emissions are fired. This means that when the incinerator is not burning TRS ( e.g. , during incinerator warm

- up and cool

- down periods when TRS gases are not being bur ned or when an alternative control device is used), the low temperature does not constitute a violation.

 To address the need for ESPs to warm to a specified temperature before full power is applied to the transformer

- rectifier set, the EPA proposed to def ine excess emissions as ESP parameter measurements below the minimum requirements during times when BLS or lime mud is fired (as applicable).

 T he EPA is also proposed language that would allow affected units to use only wet scrubber liquid flow rate (or li quid supply pressure) to demonstrate compliance during periods of S/S because pressure drop is difficult to achieve during these periods.

C ommenter 0059 believe s it is appropriate for EPA to acknowledge that operations of control equipment are different during periods of S/S than during periods of steady state, normal operation and indicated that the proposed monitoring provisions that accommodate these differences in operation are appropriate. However, the commenter stated that ad ditional provisions are needed to more fully account for S/S periods , as discussed in the following paragraphs

.79

Startup and ESPs

. With PM emissions from recovery furnaces (and some lime kilns) controlled using ESPs

, commenter 0059 noted that subpart BB a a s proposed does not require compliance with the opacity standard until BLS or lime mud is being fired, which provides time for the
operators to warm up the equipment on auxiliary fuel, su ch as fuel oil or natural gas. Noting that

t he ESP cannot practica b ly be engaged until a certain flue gas temperature is reached , the

commenter said that p remature starting of this equipment would lead to short

- term stability problems that could result in unsafe actions and longer term degradation of ESP performance due

to fouling, increased chances of wire damage, or increased corrosion within the chambers. The commenter pointed out that v endors providing this equipment incorporate these safety and operational concerns into their standard operating procedures. 125

According t o the commenter, d uring periods of startup, auxiliary fuel ( e.g. , fuel oil or natural gas) is introduced to the furnace or kiln and the ESP warms up on a designated curve that could

last for a few hours. The commenter noted that s ome ESPs have O 2 sensors a nd alarms that shut down the ESP at high flue gas O 2 levels to avoid a fire in the unit. The commenter further noted

that the O 2 level is typically high during startup, so the ESP may not engage due to these safety

controls until more stable operating cond itions are reached. In addition, the commenter noted

that w hen the furnace or kiln is started on residual oil, the ESP cannot be engaged until a certain temperature is reached to avoid fouling the plates.

The commenter pointed out that o perators have a fi nancial incentive to minimize the time spent in startup. According to the commenter, w hen units are starting up, they are not operating in the most efficient mode, auxiliary fuel is being burned, and the process is not operating optimally. Therefore, the c ommenter indicated that furnaces and kilns are started up as expeditiously as possible, but safety concerns cannot be ignored, and proper procedures must be followed. The

commenter stated that EPA wa s correct in applying the opacity standard only after BLS or lime

mud is introduced into the furnace or kiln. However, the commenter pointed out that ESPs are operated using a power management system to ensure the most efficient mode of operation. According to the commenter, t he efficient functioning of an ESP m eans minimizing power consumption and maximizing dust collection. T he commenter noted that t hese automated power
management systems sense the amount of loading and adjust the amount of current applied accordingly, based on the spark rate. Therefore, the co mmenter stated, at low loads during S/S

when BLS or lime mud is being fired at less than normal operation, the secondary current may not be within the range achieved during the last performance test, but the ESP would still be operating optimally. As a res ult, t he commenter explained, the first 12

- hour block average secondary current or total secondary power reading could be less than the established operating parameter range, but the PM emissions and opacity could below the standards.

Therefore, the comme nter request ed that EPA exclude from the definition of excess emissions all

12

- hour average measurements of secondary current or total power during S/S that are less than

the site

- specific operating parameter limits

, as it has done for scrubber pressure dr op. 126 Given

the difficulties associated with maintaining steady secondary current, and extending the logic

behind allowing liquid flow rate (as opposed to pressure drop) for scrubbers during S/S

, the

125 See Appen dix I of AF&PA’s August 23, 2010 comments on the June 4, 2010 proposed Boiler MACT rule for an excerpt of an ESP operational manual.

126 S ee §60.284a(d)(4)(ii) and (5)(ii).80

commenter requested that EPA also allow facilities to mon itor only secondary voltage during

S/S

.

Longer averaging times

. In addition to incorporating provisions that address the S/S issues raised above, commenter 0059 requested that EPA also incorporate a longer averaging time to the

various emission standards ( e.g. , 24

- hour average) to better account for short safety venting episodes and short excursions during S/S

. The commenter also requested that the definition of

excess emissions in subpart BB 127

— as a period in excess of 5 minutes where gases are not

combuste d at a temperature of at least 1200°F

— should be retained in subpart BB a. The commenter argued that EPA had not provided a sufficient rationale for its elimination. The commenter noted, h owever, that a longer averaging time or a 5

- minute allowance w ould not be

sufficient to account for the time needed to safely start up digester, evaporator, stripper, and

BSW systems

, and

, thu s, the commenter indicated other changes are necessary

, as discussed

above.

Response: The commenter supports and understands corr ectly our proposals regarding operating parameters and the applicability of TRS limits during recovery furnace and lime kiln operation. Similarly, they understand and support our proposal on O 2 correction of TRS CEM S readings. We appreciate their support and are finalizing those sections of the proposal. These monitoring provisions were developed in recognition that selected parameters during S/S periods may different from parameters observed during normal steady

- stat e operations.

T he commenter’s observation regarding ESP secondary current during periods of low load, such as would occur during S / S, is helpful. The commenter notes that f or control systems where an ESP is followed by a wet scrubber, the ESP secondary cu rrent (or total secondary power which is calculated using secondary current) can be below the established operating parameter range while the PM and opacity limits meet the standard. We agree with the commenter that secondary current (or total secondary po wer) can vary during startup and shutdown. We have changed the

definition of ESP

- related excess emissio ns for combined ESP/ scrubber controls in §60.284a(d)(5) of the final rule to include all 12

- hour block averages of ESP secondary voltage

below the minimu m operating limit at all times (including S/S) , and all 12

- hour block averages of secondary current or total secondary power below the minimum operating limit at all times except during S/S . The rule changes make the S / S accommodations proposed for wet scrubbers and those for this type of ESP comparable. This change does not apply f or systems that only employ an ESP and have longer averaging periods in conjunction with an opacity limit.

Given the 12

- hour averaging times for most parameters and other changes incorporated into the final rule to promote consistency between subpart S and subpart BBa, we do not believe it is necessary to also lengthen the averaging time for continuously monitored parameters or to
reinstate the definition of excess emissions as a period in excess of 5 minutes where gases are not combusted at a temperature of at least 120 0°F

.



### 4.2 Periods of Malfunction

127 S ee §63.284(d)(3)(ii).81

4.2

- 01 Comment: Commenter s 0059 and 0061 contended that EPA is required to take

malfunctions into account when adopting NSPS. According to the commenter s
, EPA categorically asserts that “section 111 does not require that emissions that occur during periods of malfunction be factored into development of CAA 111 standards,” 128 but offers very little support for that assertion, other than stating its own, often counterintuitive, conclusions.

C ommenter 0059 indicated that the plain language of section 111 and the explicit direction of all

of the relevant case law state that malfunctions must be accommod ated by the NSPS if they in fact are to be achievable when using the best demonstrated control technology on which the

NSPS are based. C ommenter 0061 argued that EPA cannot simply change its mind without providing a factual analysis supporting its new conc lusion that NSPS need not include the allowances for malfunctions that were included in dozens of NSPS issued over the past 40

years. 129

C ommenter 0059 rejected EPA’s claim that the technology basis for NSPS incorporates the notion of “operating units in su ch a way as to avoid malfunctions” and setting emission standards at levels “achieved by a well

- performing non

- malfunctioning source.” 130 The commenter stated that EPA’s claim has no basis in the statutory language or the case law. According to the

commenter , rather than set standards of performance that reflect what is achieved by demonstrated technology as the statute requires, the EPA has instead assured that the proposed NSPS are inconsistent with the statutory criteria for NSPS, by assuring that sources will be in

violation of the standards despite installation of the identified control technology. 131 Far from being “consistent with section 111 and... a reasonable interpretation of the statute,” 132 the commenter argued that EPA’s approach to malfunctions disreg ards congressional intent that NSPS be achievable with demonstrated technology and instead sets limits EPA knows sources will violate even if they install that technology and operate and maintain it properly.

According to commenters 0059 and 0061, EPA ass erts that emissions during malfunctions

should not be used to characterize the source’s operations for purposes of deriving NSPS . The commenters cited EPA’s argument that NSPS should be characterized only by a source’s emissions during normal operations, because “accounting for malfunctions would be difficult, if not impossible, given the myriad different types of malfunctions that can occur across all sources in the category and given the difficulties associated with predicting or accounting for the frequ ency, degree and duration of various malfunctions that might occur

. ” 133 Commenter 0061 contended that, o n its face, acknowledging that malfunctions are part of the affected facility’s operation, but then excluding emissions during malfunctions when determini ng emission limitations for the affected facility, makes no sense.

According to commenter 0061, EPA acknowledges that even properly designed and operated equipment will sometimes exceed emission limitations based on steady

- state operation

, due to

128 See 78 FR 31329 , col.1.

129 See, e.g. , Transactive Corp. v. United States , 91 F.3d 232, 237 (D.C. Cir. 1996) (agency must provide a “reasoned analysis” to support departing from prior practice).

130 See 78 FR 31329

. 131 See id

. (recognizing that “even equipment that is properly designed and maintained” can be expected to fail sometimes, and therefore not to achieve the emission limitations EPA is proposing).

132 See 78 FR 31329

. 133 See id

.82

malfunct ions. 134 The commenter stated that operators of the affected facility 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 r esponse actions. The commenter agree d with EPA’s conclusion that the factual complexity of differing processes and of the severity, frequency, and duration of malfunctions makes standard

- setting

difficult. 135 In addition, the commenter pointed out that it is often impossible to gather emission data during malfunctions either for standard

- setting or for compliance demonstration purposes. According to the commenter, m alfunctions are by definition unexpected, so it is not possible to plan to have test equipment in place to measure emissions when one occurs. The commenter also pointed out that, e ven if test or monitoring equipment is in place, emissions during malfunctions 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.

Rather than supporting 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 , commenters 0059 and

0061 said these findings should lead EPA to its authority under CAA section 111(h) to prescribe alternative design, equipment, work practice, or operational standards where it is not feasible to

set or enforce a numerical emission limit. Commenter 0059 pointed out that EPA has done so in

s ubpart BB and should do so in s ubpart BBa as well. 136 The commenters argued that EPA cannot rationally defend its articulated view that applying the concept of “best system of emission reduction which ... has been adequately demonstrated” to periods during which a source is malfunctioning “presents difficulties.” 137 T he commenters contended that t his ignores the fact that there are work practices that represent the best practices for minimizing emissions during a

malfunction. Wh ile the measures that represent these best practices will depend on facility

specific issues, such as process design, pollution control train, and other factors, the commenters

said they are nonetheless the “best system of emission reduction which ... has be en adequately
demonstrated.” 138

Commenter 0061 noted EPA ’s claim that “accounting for malfunctions when setting standards of performance under section 111...could lead to standards that are significantly less stringent than levels that are achieved by a well

- performing non

- malfunctioning source.” 139 According to the

commenter, t hat “end justifies the means” rationale ignores the congressional directive that NSPS are to represent limitations that have been achieved in practice and that reflect operation of

134 See i d

. 135 See id

. 136 EPA suggests that its position is supported by Weyerhaeuser Co. v. Costle , 590 F.2d 1011 (D.C. Cir. 1978). But that opinion: (a) involved a CWA “technology

- forcing” requirement that is different from the best demonstrated technology requirement of CAA section 111; (b) was issued long before the D.C. Circuit concluded in NRDC v. EPA, 859 F .2d 156 (D.C. Cir. 1988) that the CWA technology

- based effluent limitations must include an upset provision to address circumstances where compliance with effluent limitations is impossible through no fault of the permittee; and (c) in any event speaks to highly unusual events (“’uncontrollable acts of third parties,’ such as strikes, sabotage, operator intoxication, or insanity”) rather than to anticipated inability of identified control technology to meet specified emission limitations 100 percent of the time. See 590 F.2d at 1058. Moreover, the fact

that there may be certain kinds of malfunctions that EPA could not reasonably account for in the NSPS does not in any way demonstrate that EPA is justified in ignoring all types of malfunctions when it establi shes the standards.

137 See 78 FR 31329.

138 See i d

. 139 See i d

.83

the “b est” control technology, taking into account various statutory factors, including cost and energy impacts...not limitations that represent the highest level of pollution control achievable. The commenter argued that i t is not reasonable and inconsistent with congressional intent for EPA to ignore the undisputed existence of malfunctions even at best

- performing sources, and then claim falsely that the best

- performing sources “achieve” emission levels that they undisputedly do not achieve part of the time. Acco rding to the commenter, since EPA described 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 representati ve of best

- performing sources. 140 T he commenter acknowledged that one goal (although not “ the goal”) of best

- performing sources is “operating in such a way as to

avoid malfunctions of their units

, ” 141 b ut the commenter said 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 0061 argued that, b y proposing an NSPS that EPA recognizes even sources with the

best demonstrated control technolo gy cannot achieve at all times, the Agency fail ed to meet the statutory requirement that NSPS be adequately demonstrated. Th e commenter stated that th is is especially obvious when one considers the multitude of conditions EPA proposes to impose on

sources during malfunctions, in order to be excused from civil penalties. According to the

commenter, EPA ma de no attempt to justify those conditions as reasonable “taking into consideration the cost of achieving such reduction and any nonair quality health and

en vironmental impact and energy requirements....” 142

Commenter 0061 also noted that EPA did not present any substantiation for its belief that “it

would be difficult, if not impossible, to take malfunctions into account in setting CAA section
111 standards.” 143 A ccording to the commenter, i t is indefensible for EPA to acknowledge that

malfunctions ar e inevitable, even for the best

- performing sources, and yet refuse to include emissions data representing malfunctions in its calculations of the emission limitations fo r the proposed standards. The commenter contended that, i f it is possible to gather sufficient representative data reflecting emissions during malfunctions, then EPA is obligated to consider these data in its calculations of NSPS for steady

- state operati ng conditions. To the extent EPA had access to continuous monitoring data for emission units using technology on which the proposed s tandards are based that included malfunction periods, the commenter said EPA could have conducted analyses of emissions lev els during malfunction events. 144 The commenter also

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. The commenter stated that EPA d id 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.

140 See id.

141 Cf. id.

142 See CAA section 111(a)(1).

143 See 78 FR 31 329.

144 Even if the continuous monitoring data are for parameters not regulated by the proposed standards, analysis of monitoring data for those other parameters during malfunction events might form a reasonable basis for EPA’s assessment of what standards are achieved or achievable during malfunctions.84

According to commenter 0061, t here are several options EPA could use for setting NSPS under

CAA section 111 that would apply during malfunction events. The commenter noted that EPA,

f or example, could establish an emission limitation that applies at all ti mes, but that has an averaging time of sufficient duration that short, infrequent spikes in emissions due to

malfunctions would not cause the source to exceed the emission limitation (while at the same

time ensuring that the source does not operate in a wa y that causes frequent, lengthy excursions above the normal controlled emission rate). The commenter stated that EPA d id not appear to have done any analysis that would show whether the averaging times proposed would accommodate excess emissions during mal functions typical of this source category.

Commenter 0061 noted that EPA also could use the flexibility accorded by CAA section 302(k) (defining “emission limitation” and “emission standard” to include “any requirement relating to the operation or mainten ance 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 t he same limits on pollutant concentrations in exhaust gases that apply during normal operations. According to the commenter, EPA could have concluded, as explained for S/S events above, that it has grounds to exercise its authority under CAA section 111(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. The commenter noted that EPA might

also use several of these approaches in combinat ion.

According to commenter 0061, there is no indication in the p roposed r ule that EPA gave much, if

any, consideration to these types of options. The commenter said that, i n short, there are ample reasons to reject EPA’s conclusory assertions that it can not take malfunctions into account when setting NSPS for kraft pulp mills. The commenter argued that EPA’s failure to evaluate these options thoroughly renders the p roposed r ule arbitrary and requires EPA to develop a new proposal.

Like commenters 0059 and 0061, commenter 0056 also objected to EPA’s argument that the CAA does not require them to include malfunction periods in development of NSPS emission

standards. 145 While commenter 0056 agreed with EPA that the emissions from malfunc tion events typically cannot reasonably be measured or monitored, making those emissions not amenable to regulation under specific emission limits

, the commenter contended that setting a single emission limitation that applies at all times, even though it cannot be met during some malfunctions (or S/S ) events, does not represent a limitation “achievable,” as required by C AA

section 111. The commenter noted that the original NSPS standards for pulp mill chemical recovery and combustion sources were written w ith the understanding that excess emissions

associated with SSM events would not be considered violations of the standards. Because of the court decision and the underlying C AA achievability criteria, the commenter said EPA must

focus its reassessment of m alfunction standards applicable to the pulp mill chemical recovery processes in a way that captures the fundamental information on best performers on which the

current standards were based . F or practical reasons , the commenter said EPA should either re

eva luate and provide adequate monitoring allowances to cover malfunctions as part of the

s tandard, or establish work practices that are feasible to implement during a malfunction ( i.e.

,

145 See 78 FR 31329.85

best engi neering and safety practices). According to the commenter, set ti ng appropriate allowances or work practice standards as the NSPS during malfunction events is t he legally

defens ible and feasible approach

.

Response: The EPA disagrees with the comment that it is required to take malfunctions into account when adopting NSPS and that a separate standard be set for periods of malfunction. As explained in the preamble, the EPA has determined that CAA section 111 does not require that

emissions that occur du ring periods of malfunction be factored into development of CAA section 111 standards. As the EPA further explained, accounting for malfunctions would be difficult, if not impossible, given the myriad different types of malfunctions that can occur across a ll sources in the category and given the difficulties associated with predicting or accounting for the frequency, degree, and duration of various malfunctions that might occur. Setting work practice standards under section 111(h) as the commenters suggest presents the same issues as setting numerical emission limits given the varied nature of malfunctions. The commenters have not suggested any specific work practices for subpart BBa equipment that could be used in place of the numeric limits during per iods of malfunction. C onsequently, to assure continuous compliance for periods of malfunction, we added affirmative defense provisions to subpart BBa.

The EPA also disagrees with the comment that our approach ignores congressional intent that the

NSPS be achiev able with demonstrated technology because the proposed NSPS does not

accommodate malfunctions . The affirmative defense provisions give the EPA the flexibility to

both ensure that its emission standards are “ continuous,” as required by 42 U.S.C. 7602(k), an d account for unplanned upsets and thus support the reasonableness of the standard as a whole.

The EPA also disagrees that we “ ignore the undisputed existence of malfunctions even at best

performing sources.” We recognized that malfunctions occur even at the best

- controlled sources

and included the affirmative defense provisions for this standard in order to address them. Also,

the comment that EPA did not consider malfunction events fro m the CEMS/COMS ICR data is

in correct. We collected and evaluated malf unction data in our CEMS/COMS analysis

.

We appreciate the commenter’s suggestion regarding the use of an “ averaging time of sufficient duration [to ensure] that short, infrequent spikes in emissions due to malfunctions would not

cause the 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)

. ” We also appreciate their evaluation of the averaging approaches

propos ed for §60.284a, though we disagree with the commenter’s assessment of the utility of such averaging approaches regarding malfunctions. The EPA has determined that CAA section 111 does not require that emissions that occur during periods of malfunction be factored into development of CAA section 111 standards , as stated elsewhere in this response. Consequently, we did not perform a specific “analysis that would show whether the averaging times proposed would accommodate excess emissions during malfunctions typical of this source category

. ” Our proposal sought to establish reasonable averaging period s that reflect the BSER at the best

controlled sources. Our initial and subsequent analyses (see section 3 of this response) both

confirm this BSER assessment. Es tablishing an averaging period is an acknowledgment that even the best sources experience some level of process variability. Further, we recognize that averaging periods can encompass events that some sources might characterize as minor equipment malfuncti ons. Such an accommodation is inherent in any averaging approach. This86

aspect of averaging periods serves to limit the circumstances where affirmative defense might apply to events that are significant malfunctions, with excess emissions def ined in §§60.28 4a(d)

and (e). Again, these excess emission definitions were reviewed using recent ICR data collected

at the best

- controlled sources. Consequently, we do not believe that affirmative defense will be frequently applicable since new, reconstructed and modifi ed sources will need to employ control technology already in use at the best sources and the prospect of affirmative defense assures that these control systems will be properly maintained.



### 4.3 Affirmative Defense

4.3

- 01 Comment: C ommenter 0059 referred to EPA’s suggestion that its position on use of an affirmative defense was supported by a recent 5 th Circuit decision in Luminant Generation LLC

v. EPA , 714 F.3d 841 (2013). The commenter indicated there are many problems with that

assertion.

1. The Luminant decision addressed EPA’s discretion to approve and disapprove SIP s under CAA section 110; it had nothing to do with establishment of standards achievable with best demonstrated technology under CAA section 111.

2. The Luminant decision largely dealt with whe ther EPA’s approval of the Texas SSM provisions was consistent with the CAA enforcement authorities in section 113(e), which again does not bear on whether use of the affirmative defense is an adequate substitute for establishing achievable NSPS under sect ion 111.

3. The Luminant court sustained EPA’s approval of a Texas SIP affirmative defense provision that includes unplanned S/S events, while EPA takes the position in the proposed s ubpart BBa preamble that an affirmative defense is not appropriate for S/S

events.

4. The Luminant decision currently is the subject of a petition for writ of certiorari pending before the Supreme Court.

Response: As stated in the proposed rule preamble (at 78 FR 31330 (col. 1 ) ), the Luminant decision is cited to support EPA’s view that an affirmative defense provision is consistent with

CAA section 113(e), which is only one part of the discussion supporting EPA’s promulgation of

an affirmative defense for malfunction events. See 78 FR 31329

- 330. Notwithstanding the comments summarized above concerning the Luminant decision, EPA stands by both its citation

of Luminant for the specific proposition for which it was cited and the overall basis for the affirmative defense as discussed in the prop osed rule preamble.

4.3

- 02 Comment: Commenter 0061 argued that the proposed affirmative defense is not a substitute for addressing malfunction events in the performance standards themselves. The commenter noted EPA’s acknowledgement that the sources that will be subject to the p roposed

r ule sometimes will be unable to comply with the p roposed s tandards because of malfunctions, even if their equipment is properly designed and maintained, through no fault of the source. 146

146 See 78 FR 31 329.87

Rather than pro mulgate a standard of performance that eliminates that situation, so that the regulated emission sources will be subject to differentiated requirements, achievable with the identified best demonstrated technology, during malfunction events, the commenter n oted that EPA offered instead an “affirmative defense.” According to the commenter, the proposed affirmative defense shifts the burden to the source to prove that a myriad number of criteria are met and actions were taken by the source (which criteria bear no direct relation to the statutory factors for standards of performance under CAA section 111), in order to avoid “civil penalties.”

The commenter contended that inclusion of the affirmative defense does not cure EPA’s failure

to set emission standards t hat are achievable during malfunctions. The commenter argued that

the p roposed s tandards, incorporating the affirmative defense, still do not represent emission limitations that have been “adequately demonstrated” to be “achievable” through use of the best control technology under CAA section 111(a)(1).

According to commenter 0061, i t is unclear where EPA f ound 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 noted that the statute is silent as to the issue and “the ordinary

default rule [is] that plaintiffs bear the risk of failing to prove their claims.” 147 While the Supreme Court has recognized exceptions such as affirmative defenses, the comme nter noted

that courts retain the authority to establish such rules unless Congress acts to delegate that authority. In this instance, the commenter said EPA had not provided any statutory authority, nor any real justification, for requiring a source to pr ove its innocence...moreover, to fully demonstrate its innocence when reporting the event...without even being charged. The commenter suggested that if EPA adopt s an approach along the lines of the proposed affirmative defense, it should be stated instead in t erms 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 malfuncti on.

Further more
, according to commenter 0061, EPA offer ed no defensible rationale for excluding

S/S events from the proposed affirmative defense. As the commenter noted above, EPA has for decades recognized in NSPS regulations that it may not be possible to meet normally applicable emission limitations, even using the best demonstrated technology, during SSM events. The commenter argued that, i f EPA persist ed in its proposal not to provide separate emission

limitations for S/S of regulated units, and if in fact excess emissions from those units c ould n ot reasonably be avoided during a S/S event , not because of failure of a process or equipment but because of the nature of conditions while starting up or shutting down the source, there is no justification fo r EPA not to provide the same kind of affirmative defense that it proposes to provide for malfunctions. The commenter noted EPA ’s statement that, through analysis of “numerous continuous opacity and TRS monitoring data set s that included periods of startup and shutdown...the affected units will be able to comply with the proposed standards at all times ,” 148

147 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 w ho 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”).

148 See 78 FR 31 328.88

and said that, e ven if this assumption is true, it would not justify excluding startup and

malfunction events from the affirmative defense, to cover those s ituations where the S/S event is of such a duration or magnitude that it causes an exceedance of the emission limitation.

Commenter 0061 maintained that, e ven if the proposed affirmative defense were not unreasonably restrictive, as discussed below, being able to assert a defense obviously is not the same as being able to comply wit h emission limitations that properly reflect the limitations of available technology as required by CAA section 111. The commenter pointed out that, a lthough

a source believes i t 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.

The commenter contended 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. 149

Furtherm ore, commenter 0061 remarked that it is not even clear what t he affirmative defense covers. The commenter noted that, i n the p roposed r ule, EPA states that the affirmative defense is “to civil penalties that are caused by malfunctions.” 150 The commenter inqu ired whether the term “civil penalties,” which wa s not defined in the p roposed r ule, 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 cont exts means only penalties imposed by a court.) The commenter also inquired whether the affirmative defense applies to “noncompliance penalties” under CAA section 120 (which apply, inter alia , to noncomp liance with a section 111 NSPS). According to the comm enter, in order t o 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

, 151 the affirmative defense would need

to apply to civil and administrative penalties, incl uding noncompliance penalties. 152

Commenter 0061 remarked that i t is also unclear how the affirmative defense would apply to

enforcement actions by state and local governments, or to private citizen enforceme nt actions

under CAA section 304. The commenter noted that the preamble to the proposed r ule, for example, sp oke only in terms of application of the affirmative defense in an EPA enforcement

action. 153 The commenter said that a n affirmative defense should clearly state that it is applicable

to enforcement actions by states or citizen

- suit plaintiffs , as well.

149 See, e.g. , Portland Cement , 486 F.2d at 398 n.1 (enforcement discretion is not a lawful means of curing rules that

create uncertai n compliance obligations).

150 See, e.g., 78 FR 31 322, 31329 , 31330.

151 Se e id . at 31329.

152 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 22.77).” 78 FR 31329, col.3. This does not answer the questions state d above. Moreover, there is no “part 22.77” in the July 1, 2012, edition of Title 40 of the Code of Federal Regulations. The proposed rule, therefore, is unclear on this key issue of what the affirmative

defense is intended to cover.

153 See 78 F R 31329, col .3 (“In any judicial or administrative proceeding, the Administrator may challenge the assertion of the affirmative defense....”) (emphasis added).89

Regarding the statement in the p roposed r ule that “The affirmative defense shall not be available

for claims for injun ctive relief,” 154 commenter 0061 noted that the preamble to the p roposed r ule

g ave no explanation for why the affirmative defense would not apply to injunctive relief. 155
According to the commenter, i f the excess emissions associated with the equipment or process failure are not reasonably preventable, then there is no apparent reason why injunctive relief

should not be available either. 156 The commenter noted that, i n fact, as a matter of law, injunctive relief may not be available in cases where a civil penalty cannot be imposed. 157

Commenter s 0059 and 0061 stated that EPA’s plan to limit the affirmative defense to civil penalties only and m aintain liability for injunctive relief renders the affirmative defense inadequate for the purpose EPA has claimed. Since injunctive relief would be available even where a malfunction was unavoidable despite installation and operation of the identified “best” control technology, the commenters argued that mills still would be subject to enforcement action, including citizen suits, and liability for rem edial action and citizens group attorneys’ fees, under emission standards that are supposed to be achievable using demonstrated technology. Consequently, 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. For the affirmative defense to provide relief from violations that were unavoidable with the specified technology, the commenters said it can not be

limited to civil penalties alone.

Commenter 0061 contended that EPA ha d not addressed these and other apparent limitations and shortcomings of the affirmative defense, which the commenter said ma d e it an inadequate

substitute for setting NSPS that i nclude provisions for SSM events. Commenter 0059 contended

that EPA’s proposal to allow an affirmative defense to civil penalties for a malfunction, if the source can meet extensive criteria, does not cure the Agency’s failure to set NSPS that are

achievab le in the first place. According to both commenters, EPA ha d 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. 158 The commenters said that the courts have adopted the same

view. 159

, 160

, 161

154 Proposed § 60.286a.

155 See 78 FR 31330.

156 EPA does not explain how excluding injunctive relief from the affirm ative defense would in practice achieve any greater protection of air quality. The affirmative defense is only available in the first place where the problem was sudden, unpredictable, beyond the control of the operator, incapable of being avoided by better design or operation and maintenance, expeditiously repaired, etc. Under those particular circumstances, it is hard to see what the basis

would be for a court to impose injunctive relief. Nor is it apparent how a court order, issued long after the ev ent but directed at these unavoidable, unpredictable circumstances, would improve air quality or otherwise implement requirements of the CAA.

157 See Sierra Club v. Otter Tail Power Co

., 615 F.3d 1008 (8 th Cir. 2010) (under concurrent remedy doctrine, injunc tive relief for a CAA violation is barred when civil penalty is barred by statute of limitations).

158 See 37 FR 17214 (Aug. 25, 1972) (establishing SSM provision in NSPS).

159 See National Lime , 627 F.2d at 431 n.46 (the promised flexibility in enforcement “ will not render ‘achievable’ a [NSPS] which cannot be achieved on a regular basis, either for the reasons expressly take into account in compliance determination regulations (here startup, shutdown and malfunction), or otherwise. ” ).

160 See also Marathon Oil Co. v. EPA , 564 F.2d at 1253, 1273 ( 9 th Cir. 1977) ( explaining why EPA’s proffered

assurances that it would not take enforcement action against sources that exceeded effluent limitations because of90

At a minimum, commenter 0061 recommended that EPA should state that the affirmative defense applies to civil penalties, civil administrat ive penalties, noncompliance penalties, and injunctive relief, in an action brought by EPA, a state, or a citizen

- suit plaintiff. The commenter

recommended that EPA also should revise the “ affirmative defense, ” so that it states that a
source “will not be deemed in violation of” the NSPS 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. 162
The commenter argued that, c onfigured in that way, this provision should be called something other than an “affirmative defense,” such as an “alternative standard for SSM events.”

Like commenters 0059 and 0061, commenter 0056 also argued that EPA’s a ffirmative defense approach for excess emissions during periods of malfunction is flawed. C ommenter 0056 said

that EPA , r ather than structure a discrete and achievable emissions standard for malfunction

events, had instead placed th ose events 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 broad and mixed set of prec ise quantitative conditions and actions with “eye

- of

- the

- beholder” qualitative conditions. The c ommenter also noted that EPA provided an affirmative d efense provision against civil penalties that requires a “preponderance” of evidence to support. 163 Accordin g to the commenter, t he a ffirmative defense policy EPA propose d to codify as potential legal protection when malfunctions lead to emissions that exceed standards, does not adequately address the issue. On its own , the commenter said the policy is overly co mplex in its documentation and reporting requirements that would be difficult, if not impossible, to meet during extreme or catastrophic malfu nction events. The commenter said the policy also is objectionable in that it shifts to the operator the burden o f proof, turning
the doctrine of “innocent unt il proven guilty” on its head.

Response: The EPA disagrees with comments regarding our decision to use affirmative defense provisions to address malfunction events. T o assure continuous compliance for periods of malfunction, we added affirmative defense provisions to subpart BBa.

upset events was “not an adequate response” to the argume nt that standards that cannot be met during unavoidable upsets fail to reflect available technology).

161 Commenter 0061noted that they are not suggesting that EPA lacks authority to include an affirmative defense provision in NSPS, but rather that doing so is not an adequate substitute for establishing NSPS that are achievable under anticipated operating conditions in the first place. The EPA has broad discretion in how it fashions NSPS. The EPA can carve out types of sources or circumstances that do not hav e to meet the emission limitations that would otherwise be imposed by an NSPS, and it frequently has. See, e.g. , exemptions for engines in certain uses in the

NSPS for Compression Ignition Internal Combustion Engines, § 60.4200; exemption from control requirement for

BSWs at mills where controls would be technologically or economically infeasible, § 60.283. Using work practice

standards under section 111(f) is also a way that EPA sometimes has provided relief from compliance with certain

numerica l standards. Contrary to objections that some have raised to affirmative defense language in NESHAPs, EPA does not usurp the role of the courts in enforcing emission standards when EPA includes an affirmative defense provision in those emissions standards; it simply is designing those emission standards so that they will, in EPA’s judgment, meet the letter and intent of the relevant statutory requirement.

162 Cf., e.g. , 40 CFR 80.613 (stating that persons demonstrating specified defenses “will not be deemed i n violation”
and are not “deemed liable for a violation” of diesel fuel sulfur program regulations).

163 See 78 FR 31329

.91

The EPA disagrees with comments that we failed to set “emission limitations that have been adequately demonstrated to be achievable through use of the best control technology .” As noted previously, the affirmative defense provisions give the EPA the flexibility to both ensure that its
emission standards are “ continuous,” as required by 42 U.S.C. 7602(k), and account for unplanned upsets and th us support the reasonableness of the standard as a whole.

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 instead

of r equiring 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 utilized where a violation has been established. The bur den of proof remains with the plaintiff in an enforcement action. 164 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. 165

The EP A further disagrees that we have offered “no defensible rationale for exclu ding S/S events from the proposed affirmative defense.” As explained in the preamble, the EPA believes that malfunction events should be treated differently than periods of S/S , which are predictable and routine aspects of a source’s operations. In contras t, the EPA has determined that CAA section 111 does not require that emissions that occur during malfunctions be factored into development

of CAA section 111 standards. Because S/S periods are part of a source’s normal operations, the same approach to comp liance with, and enforcement of, applicable emissions standards during those periods should apply as otherwise applies during a source’s operations. Further, as explained above, periods of S/S

— but not malfunctions

— are taken into account when establishing s ection 111 emissions standards. For these reasons, the EPA does not believe it is appropriate to apply the affirmative defense provision to S/S periods. Additionally, this argument is not accurate since malfunctions that occur during S/S would be eligible for coverage under the

affirmative defense. Consequently, the EPA is promulgating the affirmative defense for malfunctions only, not for periods of S/S

.

The commenter correctly observes that the affirmative defense provisions do not relieve a source

from any reporting obligations required by the standard or noncompliance certifications under

the CAA

. Sources are required to comply with the standards at all times, including periods of malfunction. To the extent a source experiences a malfunction that causes the source to exceed

the excess emission allowances defined in §60.284a(d) and (e) , the source is in noncompliance and subject to penalties unless the source demonstrates that the affirmative defense applies. The source will need to include in its malfunction report the additional calculations and an explanation to demonstrate that the source complied with the standard notwithstanding the

malfunction event.

164 See, e.g. , 40 CFR 22.24.

165 See, e.g. , Arizona Pub. Serv. Co. v. EPA , 562 F.3d 1116, 1120, 1129

- 30 (10 th Cir. 2009) (rejecting industry challenge to the EPA’s use of an affirmative defense to address excess emissions during malfunction events).92

The commenter indicates the coverage of affirmative defense or its applicability to injunctive

relief is not clear. 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 st ate 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 commenters is not on point and does not undermine EPA’s ability to limit the affirmative defense to penalty claims. The concurrent remedy doctrine

prov ides 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. The EPA does not intend to provide an affirmative defense to criminal charge s, 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 negligent release that threatens imminent danger to persons (CAA section 113(c)(4) and (5)). In these circumst ances, 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, such circumstances can be raised in any enforcement action and may be the

basis for a defense. The affirmative defense is available in any 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. Although the preamble‘s reference to the ‘Administrator’ may have c aused some confusion, there is nothing in the language of the regulatory text establishing the affirmative defense that suggests that the affirmative defense is limited to EPA enforcement actions.

The commenter indicates that coverage of affirmative defe nse to private citizen actions under

CAA section 304 is unclear

. The EPA’s view is that the affirmative defense is consistent with CAA section 304, as well as section 113(e). Section 304 gives district courts jurisdiction “to apply appropriate civil penalt ies.” 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 re gulatory 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 pursua nt to the section 113(e)(1) factors does not occur. In exercising its authority under section 111 to establish emission standards (at a level that meets the stringency requirements of section 111), the EPA necessarily defines conduct that

constitutes a vio lation. 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 a re 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 allo ws 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 p rovision 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 v iolation (not93

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 standard s 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 penaliz ed for violations caused by malfunctions that could not have been prevented and were otherwise appropriately handled (as reflected in the affirmative defense criteria). The EPA has utilized 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 with the statement that we are relying “on enforcement, rather than regulatory language, to address the inability to comply with technology

- based standar ds during SSM events.” 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 emissio n limits that are caused by

malfunctions. Regarding Marathon Oil , the Court clearly states the following in its opinion regarding an affirmative defense : “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.” The affirmative defense comports with the court‘s suggestion

in Marath on 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.

4.3

- 03 Comment: Commenter 0061 argued that the proposed affirmative defense as written is unreasonable and imprac ticable. According to the commenter, i f EPA refuses to set alternative emission standards that apply during SSM periods and continues to rely instead on the proposed affirmative defense, the affirmative defense must be substantially modified for it to prov ide any significant relief. First, as noted above, the commenter said the affirmative defense 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. Th e commenter indicated that if EPA does that, it may be unnecessary to state also that the affirmative defense relieves the source from liability for all types of penalties and injunctive relief (save criminal penalties), but that should

be the clear effect of qualifying for the affirmative defense.

Commenter 0061 suggested that affirmative defense should be available not only for malfunctions, but also for excess emissions, if any, during S/S . As the commenter stated above, there is no logical reason why a source that experiences excess emissions during S/S periods that were not reasonably preventable (either because the source experienced conditions EPA did not anticipate in setting the standards, or because EPA’s assumption about the achievability of thos e standards during S/S periods was wrong) should be excluded from the affirmative defense.

Commenter 0061, with the support of commenter 0059, argued that many aspects of the affirmative defense would make it unavailable as a practical matter for many, if not most malfunctions. According to commenter 0061, many of the limitations on the affirmative defense are not directly related to the question of whether an exceedance of the emission limitations due

to a malfunction should be excused. Commenter 0061 fur ther stated that EPA needs to substantially revise and streamline the proposed affirmative defense for it to be of practical

value. Commenters 0059 and 0061 both noted that EPA has estimated that there will be no more94

than two instances of a mill seeking t o avail itself of the affirmative defense during the first 3 years after the subpart BBa standards are promulgated. 166 Commenter 0061 argued that this is inconsistent with EPA’s recognition of the fact that mills with the identified technology still will experience unavoidable exceedances from time to time, and its estimate that nearly 20 emission units will be subject to subpart BBa during that period. 167 According to commenters 0059 and 0061, EPA’s assumption that those mills will not even attempt to invoke the affirmative defense even once a year is a clear indication that the affirmative defense as proposed fails entirel y to meet the statutory requirement that NSPS be set at a level that facilities will be able to meet with the identified control technology.

According to commenter 0061, several of the conditions for establishing an affirmative defense in proposed §60.286 a list numerous items which may be appropriate considerations in determining whether excess emissions during a malfunction should be considered a violation, but which ought not to be listed as mandatory criteria, all of which have to be met in order for an exceedance to be excused. For example, the commenter cited proposed §60.286a(a)(1)(i), which requires that the excess emissions must have been “caused by a sudden, infrequent, and unavoidable failure of air pollution control and monitoring equipment, proc ess equipment, or a process to operate in a normal or usual manner....” The commenter remarked that there is no apparent reason why a “sudden” and “unavoidable” equipment failure or process upset leading to emissions greater than the NSPS should be considere d 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.” 168

Commenter 0061 noted that a number of the conditions for establishing an affirmative defense use phrases that are subject to a wide range of interpretations, and that on their face do not recognize any need for reaso nableness or cost

- effectiveness. The commenter inquired how the enforcement authority, or a judge, would determine whether “proper design” or “better operation and maintenance practices” could have prevented a malfunction (§60.286a(a)(1)(ii)), whether a

re curring malfunction is a result of “inadequate design” (§60.286a(a)(1)(iv)), whether repairs were made “as expeditiously as possible” (§60.286a(a)(2)), whether the source took “all possible steps” to minimize the impact of the excess emissions (§60.286a(a) (5)), and whether emissions monitoring and control systems “were kept in operation if at all possible” (§60.286a(a)(6))? The commenter contended that affirmative defense, as proposed, leaves open the possibility that a

source will be considered to be in vi olation because the enforcement authority decides 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. According to the commenter EPA or the court may, in

effect , impose an extreme version of best demonstrated technology, during malfunction periods. The commenter contended that the vague and unqualified descriptors in the criteria for demonstrating the affirmative defense will, at a minimum inevitably lead to vary ing conclusions as to whether a violation has occurred, resulting in inconsistency from one jurisdiction to the

next.

166 See 78 FR 31 333.

167 See 78 FR 31332.

168 See § 60.286a(a)(1)(ii) and (iv).95

Noting that proposed §60.286a(a)(6) requires, as a condition for the affirmative defense, that all emissions “control systems were kept i n operation if at all possible,” commenter 0061 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 argued that this provision

shoul d be qualified, as EPA has qualified similar provisions in the NSPS General Provisions in 40 CFR 60.11(d) and the NESHAP General Provisions in 40 CFR 63.6. As an example, the commenter advised that 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 o r standby pollution control equipment. 169
According to the commenter, EPA has long recognized, in the General Provisions applicable to NSPS, that it is appropriate to require sources to operate the affected facility and related air pollution control technolo gy “to the extent practicable ... consistent with good air pollution control practice for minimizing emissions” during SSM periods, not “if at all possible.” 170 The commenter argued that EPA cannot abandon those rational approaches and adopt the kind of

absolu te requirements implied by the proposed rule, without an explanation of why it is necessary and appropriate to do so.

According to commenter 0061, proposed §60.286a(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 , personal injury, or severe property damage.” The commenter argued that this language is stated in such strong terms that it may be difficult or impossible for a source to demonstrate that it met this criterion, even though bypassing the control equipment or the process was an appropriate exercise of good air pollution control practices. As an example, the commenter noted 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 noted that there can be substantial room for disagreement ab out what constitutes “severe” property damage. Besides the unclear and subjective nature of these criteria, the commenter said there is nothing inherent to standards of performance under CAA section 111 that requires a source to avoid bypassing control equ ipment to such a degree. Lastly, the commenter contended that it is not apparent at all why the CAA would disfavor bypassing “a process”

— as opposed to pollution control equipment

— in this way.

Commenter 0061 noted that, under proposed §60.286a(a)(5), a sou rce claiming the affirmative defense must prove that “[a]ll possible steps were taken to minimize the impact of the excess emissions on ambient air quality, the environment and human health.” In addition to the subjective term “all possible steps,” the com menter argued that this provision again presents a disconnect between the absolute and extreme requirement of the affirmative defense and the

169 See, e.g. , 40 CFR 63.483(a), 76 F R 22566, 22583, 22588 (April 21, 2011), where EPA agreed it was appropriate to include such a qualifier in comparable language in NESHAPs: “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 t his standard have
been achieved.” 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).

170 See 40 CFR 60.11(d).96

provisions of the CAA designed to attain ambient air quality standards and protect human health

and the environmen t. Commenter 0061 argued that the CAA does not require sources to take “all possible steps” to control emissions; the commenter pointed out that, even for HAPs, the CAA specifies a level below which further reductions are not required. 171 In addition, the co mmenter said it is unclear how this criterion for qualifying for the affirmative defense differs from proposed §60.286a(a)(3), which requires that the frequency, amount, and duration of excess emissions “were minimized to the maximum extent practicable.” U nless EPA explains what additional showing would be needed by §60.286a(a)(5), the commenter recommended that it

should be eliminated.

According to commenter 0061, the requirement proposed in §60.286a(a)(8)

— that the source must show that “[a]t all times, t he affected source was operated in a manner consistent with good practices for minimizing emissions” (emphasis added)

— could be read to go way beyond an analysis of why equipment may have malfunctioned and place an overwhelming burden on the

source to meet a “good practices” standard (undefined) for the whole industrial plant or commercial premises. The commenter pointed out that this factor potentially could allow a regulatory enforcement official to judge the entirety of operations at a site against a mult itude of arbitrary “good practices” and subjectively find the stationary source lacking, thereby denying the source the ability to assert an affirmative defense for NSPS applicable to a particular operation at the site. If EPA retains this condition for th e affirmative defense, of demonstrating operation consistent with good practices for minimizing emissions, the commenter insisted the Agency must clarify that this condition applies to the “affected facility,” as that term is defined

in 40 CFR 60.2. If EPA really does intend for this condition to apply to operation of the entire site, and not just “the apparatus to which a standard is applicable,” 172 the commenter insisted that EPA must explain why it has the statutory authority to shift the focus of the prop osed standards from the apparatus subject to the NSPS to the plant as a whole. The commenter indicated that this does not appear to be EPA’s intention, however, since, in apparent response to their comments, EPA changed the similar provision in the final N SPS for Nitric Acid plants to read “the affected facility was operated,” rather than “the affected source was operated” in a manner consistent with good practices for minimizing emissions. 173

Commenter 0061 argued that the requirement in proposed §60.286a(a )(9) that the source prepare 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 f or standard

- setting under section 111. The commenter said that read literally, the provision 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 un able to correct that cause. Noting that EPA has defined a malfunction as an event that is “unavoidable” and unforeseeable, and “not reasonably preventable,” 174 the commenter said that it, therefore, may not always be possible to identify and address the spec ific causes of the

171 See CA A sections 112(d) and (f).

172 S ee 40 CFR 60.2 definition of “affected facility.”

173 See 40 CFR 60.74a(a)(8), 77 FR 48 433, 48447 (Aug. 14, 2012).

174 See proposed § 60.286a(a)(1)(i) and (iii) and 40 CFR 60.2.97

malfunction or the excess emissions associated with it. 175 The commenter also noted that requiring the facility to eliminate the primary causes of the malfunction, without regard to “taking into account the cost of achieving such” eliminat ion and the “nonair quality health and environmental impact and energy requirements” associated with its elimination is unreasonable and entirely inconsistent with the criteria for NSPS established under CAA section 111(a)(1). 176

Commenter 0061 also reporte d as unreasonable and unnecessary the requirement in proposed §60.286a(b) to submit a written report to the Administrator “with all necessary supporting documentation,” indicating that the source met all of the multitude of criteria for the affirmative

def ense, which report is to be included in the first periodic compliance, deviation or excess emission report. 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 or her enti re defense before he or she is even notified of a potential enforcement action. The commenter argued 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 un der 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.

Commenter 0061 noted that, according to proposed §60.286a(b), if the compliance, deviation or

excess emission re port 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 relevan t standard. The commenter noted that the proposed minimum 45

- day period for submitting a written report demonstrating that the source qualifies for the affirmative defense commences on the date of “the

initial occurrence of the exceedance of the standard.” 177 The commenter said this presents several problems. According to the commenter, much of the required content of that written report could

not be created until the malfunction event ceased

— which could be days or even weeks after the

malfunction commenced. The commenter said this could make the amount of time the source would have, in practice, to prepare the report much less than it might seem.

Response: We disagree with the commenter’s statement that qualification for affirmative

defense should absolve a source from any violation of the applicable standard. That is not our

intent. Sources are required to comply with the standards at all time s , including periods of

175 EPA has long acknowledged this reality in the General Provisions applicable to NSPS, which require 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).

176 For example , 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. But this would not reflect control technology that has been “adequately demonstrated,” nor would the NSPS take cost and other factors into consideration as the statute requires. On the other hand, even with redundancy and extra capacity certain sources can in cur malfunctions that would result in excessive emissions. Moreover, 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 o f EPA’s authority under the CAA, which is limited to establishing and enforcing emission limitations, not dictating plant operations.

177 See proposed § 60.286a(b).98

malfunction. To the extent a source experiences a malfunction that causes the source to excee d

the excess emission limits defined in §§60.284a(d) and (e) , the source is in noncompliance and subject to penalties unless the source demonstrates that the affirmative defense applies. If there is

a violation of the emission s standard and the source demo nstrates that all the elements of the affirmative defense are met, only injunctive relief is available.

The commenter appears unclear about the availability of an affirmative defense during S/S . As

stated above

, the affirmative defense is available for malfunctions that occur during S/S and during the normal course of operations.

We do not agree with the opinion that our estimate on the future use of the affirmative defense in subpart BBa indicates that it is not a pr actical standard. Rather, we believe that our proper application of BSER serves to limit the circumstances where the affirmative defense might apply to events that are significant malfunctions, with excess emissions defined in §§60.284a( d) and (e). The NSP S excess emission definitions were reviewed using ICR data collected at the best

controlled sources. Consequently, we do not believe that the affirmative defense will be frequently applicable since new, reconstructed and modified sources will need to emplo y control technology already in use at the best sources and the prospect of the affirmative defense assures that these control systems will be properly maintained.

The commenter questions the use of several terms and phrases used to describe circumstances characterizing malfunctions eligible for the affirmative defense

– ‘sudden,’ ‘infrequent,’ ‘proper design,’ ‘better operation and maintenance practices,’ ‘unavoidable to prevent loss of life, personal injury, or severe property damage,’ ‘all possible steps ,’ ‘good practices,’ etc. The commenter describes these phrases as vague
, unqualified descriptors and “extreme terms” that should not become mandatory criteria. The comme nter expresses concern that terminology will be applied inconsistently. We disagree. T hese words and phrases provide parameters needed to facilitate assessments made by delegated authorities responsible for determining the reasonableness of an affirmative defense claim. Contrary to the commenters concerns, these

terms have a successful hist ory of consistent application. Many were modeled after the conditions of the affirmative defense in EPA‘s 1999 SIP SSM policy, which several states have adopted into their SIPs. We do not have any indication that parties to enforcement proceedings

have had any significant difficulties applying the terms of these SIP affirmative defenses. Other

conditions are modeled after a FIP promulgated by EPA. 178 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 disagrees with suggestions that it is unnecessary to satisfy all of the requirements of the affirmative defense. As noted above, the requirements set forth in the affirmative defense provision s are modeled after the conditions of the affirmative defense in EPA ’ s SIP SSM policy. Additionally,

affirmative def

ense provisions are now in multiple rules, and EPA has both received comment and made reasonable adjustments to the terms we have proposed. 179 The EPA disagrees that

other terms and conditions in § 60.286a or in the other conditions of the affirmative defense are overly subjective or extreme or need further qualification. EPA acknowledges that some of the criteria may overlap to some extent and under some circumstances but does not believe it is necessary to change the requirements. To the extent there is over lap, the same information can be

178 See 40 CFR 50.1312.

179 See, e.g. , EPA

- HQ

- OAR

- 2009

- 0559

- 0171 chapter 15.99

used to meet the provisions in question. Consequently, we have concluded that establishing these parameters for evaluating malfunctions is the best approach to determining eligibility for the affirmative defense provisions.

We disagree with the comment on root cause analyses. 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. A roo t cause analysis 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 ro ot cause analysis is one example of what constitutes good air pollution control practices to minimize emissions. A root cause analysis is not required for every malfunction

- only those malfunctions for which the source chooses to assert an

affirmative def

ense. Not every malfunction is so significant that it would require asserting an affirmative defense. The EPA believes that sources seeking to minimize emissions will endeavor to find out what went wrong anytime there is a minor or major malfunction. The f acility should decide what level of investigation is needed in each instance. 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 meaning ful results which successfully identify and address the cause of the malfunction. However, if the malfunction rises to the level

of one that the source seeks to avail themselves of the affirma tive defense, then a root cause analysis is required. In the con text of section 111, 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 a nd causes 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 part 60 General Provisions) or in the subpart being promulgated, subpart BBa. 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 60.

With respect to the commenter’s suggestions on the timing of the reporting requirements, the written reports required to demonstrate that the affirmative defense provisions have been met may be submitted electronically , providing the facility with greater flexibility on the timing of the reporting requirements

. In addition, the facility has the option to submit a request for an extension of the deadline for these reports, and this request may also be submitted electronically

. Consequently, we believe the re porting requirements to be reasonable and have decided to finalize the reporting requirements as proposed.

We believe 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.100 

## 5 . Testing and Monitoring

5.1 Emissions Testing

5.1

- 01 Comment : Commenters 0058 and 0059 noted that EPA is propos ing under subpart BB a to require initial and repeat CPM emissions testing in conjunction with filterable PM testing, citing the lack of CPM data and the need to develop a better understanding of CPM emissions from pulp and paper sources. The commenters contended that initial a nd repeat performance testing of CPM may not help address current data gaps, given the unresolved method artifact and bias issues associated with the new EPA Method 202. According to the commenters, r ecent work carried out by commenter 0058 has identified several unresolved issues with the new version of EPA Method 202, which was promulgated in December 2010. The commenters provided a summary of the s ignificant findings from the ongoing technical studies on CPM measurement

and emissions (with the details pr ovided in an attachment to commenter 0058’s comments) . The summary items are listed below.

1. Method evaluation studies carried out by commenter 0058 indicate that the new M ethod 202 yields train blank values ~6.0 mg. The EPA’s field evaluation study also yi elded an average train blank of 5.33 mg, with values ranging from 4.6 to 6.2 mg. However, the currently promulgated version of M ethod 202 only allows a maximum blank correction of 2 mg. The resulting positive bias associated with subtracting only 2 mg (as opposed to the observed ~6.0 mg) can be a significant component of the total CPM measured during

tests on low

- emitting sources.

2. Commenter 0058’s studies on a low

- emitting source (natural gas package boiler) using

the new M ethod 202 also indicate the potent ial for positive bias due to the capture of SO 2 in the impingers and subsequent characterization of this SO 2 as sulfate ( and CPM) in the

method. The positive biases resulting from (a) the use of an inappropriate blank correction and (b) the formation of method artifacts are also relevant for the sources covered by this rulemaking.

3. Commenter 0058 recently carried out characterization studies on concurrently collected filterable particulate (EPA Method 5

– front half) and CPM (new EPA Method 202

– back half) sa mples from a DCE recovery furnace. The primary cation captured in the CPM

train was ammonium , while the anions included sulfate, chloride, and carbonate. By comparison, the front half sample did not contain any ammonium , suggesting that the

ammonium captur ed in the back

- half cannot be attributed to a partial breakthrough of filterable particulate. The presence of sodium in the front

- half catch, and its absence in

the back

- half catch, further confirms that there was no breakthrough of filterable particulate ( Na 2 SO 4 particulate is captured on the front

- half filter). These results indicate the potential for positive bias in CPM measurements in the presence of free ammonia. Any free ammonia in stack gases would pass through the front

- half filter, react with any acid gases to form ammonium sulfate or ammonium chloride, and be characterized as CPM during subsequent gravimetric measurements. Ammonium was also identified as the predominant cation on CPM filters obtained from wood

- fired boilers.

4. Commenter 0058 has als o carried out characterization studies on the CPM catches from three DCE furnaces and three NDCE furnaces. Ammonium accounted for ~30 percent of the total CPM mass captured in two of the three DCE furnaces and 5 to 10 percent of the101

total CPM mass in the t hree NDCE furnaces. 180 Ammonium accounted for 15 to 25 percent of CPM mass collected during sampling on six lime kilns and from 10 to 35 percent of CPM mass in three SDT s. 181 These results indicate the potential for positive

bias in CPM measurements due to fre e ammonia: ( a ) is relevant for the sources covered in this rulemaking ( recovery furnaces ) , and ( b ) merits a more thorough investigation.

Commenter 0058 is carrying out additional CPM method evaluation studies as part of the ongoing technical studies program, including ( a ) identifying the source and extent of SO 2 and other method artifact biases, ( b ) comparing the performance of M ethod 202 against other equivalent test methods, and (c ) developing modifications to mitigate these issues. Therefore,

comme nters 0058 and 0059 recommended that EPA defer proposing the CPM testing requirement until more information on the unresolved method issues becomes available. According to the commenters, any CPM data generated in the interim will be of questionable qualit y and will further contribute to the uncertainty surrounding CPM emissions.

Response: The EPA acknowledges and appreciates the independent efforts of commenter 0058 to improve the implementation of EPA’s reference method for CPM (Method 202). The EPA

als o acknowledges the commenter ’s concern with the current implementation of the method by

the testing community. The EPA is working to address those issues with implementation by the testing community and will collect and consider the blank levels in the use of the data . The

comments listed above (Nos. 1 through 4) are addressed one

- by

- one in the paragraphs below.

1. Field blanks in this context represent material present in the sampling system that was not removed from initial cleaning and material carryover that was not removed when samples were collected during serial use of the sampling equipment. The intent of the field blank

is to alert the tester t o residual material beyond that determined to be an inherent correction to the method to enable the tester to identify the cause of the residual material and implement best practices to minimize this residual. Field bla nks reported to EPA from the testers using Method 202 range from less than 2 mg per sampling train to more than 10 mg. Testing firms that measure less than 2 mg per sampling train of residual condensable mass have identified and instituted best practices t o routinely maintain th is

low residual mass in their field blanks. Proof blanks described in the method can be used

to determin e if a particular tester has an inherent blank or contamination issue that should be resolved before routine implementation of th is method. The EPA disagrees that the excess ( greater than 2.0 mg) field blank resulting from commenter 0058’ s tests is attributable to artifacts. The field test data supplied by the commenter do not contain documentation that the glassware was heated to o ver 300 o C or that a p roof b lank was performed to verify that particulate residue was not introduced from improper sample train preparation. If one assumes that the sample trains were appropriately prepared and discounts the lack of documentation, any resid ue in the field blank is likely to originate from either contamination or residual particulate which was not removed during the sample train recovery process. Neither the inability to control contamination nor the inability to recover all of the PM collect ed by the sample train is an indication that the

additional residue is an artifact.

180 Unpublished results from NCASI study

. 181 See id

.102

2. The EPA acknowledges that Method 202 sampling runs of longer duration accumulate additional condensed moisture and run the potential to generate SO 2 artifact in much the

s ame way as the previous version of Method 202 behaved. The positive biases resulting from increased potential for SO 2 absorption in the condensed water combined with longer exposure to this greater accumulation of moisture can be overcome by periodic remov al and purging of the moisture as allowed in the method. The EPA recommends that

commenter 0058 institute this best practice to minimize the impact of the longer sampling runs they feel necessary to achieve sensitivities necessary for use of the Method 202

CPM data.

3. The EPA acknowledges that ion characterization studies of filterable particulate and CPM samples showed the primary cation captured in the CPM train was ammonium with potential balancing anions of sulfate, chloride, and carbonate. The comparison of the ion

characterization of the filterable and condens a ble fraction provides an incomplete assessment of the stack matrix and how it interacts with the sampling train a nd immediately in the atmosphere. Also

, as indicated in several published studies, 182 higher concentrations of ammonia are known to react quickly with SO 2 at ambient temperature to form primary ammonium sulfate particulate near or at the stack exit. Therefor e, we believe Method 202 correctly measures primary ammonia particulate and should be characterized as CPM during subsequent gravimetric measurements

. We have included these published studies in our docket for those who are interested in a better

understan ding of this issue.

4. The EPA appreciates information and comparison of reference Method 202 results with other “equivalent test methods” to further understand the differences between the

methods. The EPA eagerly anticipates comparison data to further evalu ate the performance of Method 202.

The EPA is retaining the requirement to conduct CPM testing in conjunction with filterable PM testing for the final rule . This requirement will apply for new, modified, and reconstructed recovery furnaces, SDT s, and lime kilns that become subject to subpart BBa over time . As we noted in the proposal, the CPM data collected will build experience with implementation of

Method 202 and will aid in research to develop a broader understanding of C PM emissions from pulp and paper combustion sources and to determine mech anisms for reducing C PM

. Because subpart BBa references Method 202, any improvements to the method that are codified in the CFR over time will automatically be referenced in subpart BBa.

5.1

- 0 2 Comment: Commen ter 0056 supported EPA’s decision to continue basing the PM emission limits compliance tests on filterable PM as measured by EPA Method 5. The commenter noted that this is the approach used under the current NSPS subpart BB and NESHAP subpart MM. The comme nter further noted that EPA is not proposing separate

standards for filterable PM 2.5 (“fine PM ”), recognizing the limited availability of PM 2.5 emission data for kraft pulp mill sources, the lack of a reliable method for measuring PM 2.5 emissions

182 See, e.g. , Burke, J. and Johnson, K., Radian Corp. Ammonium Sulfate and Bisulfate Formation in Air Preheaters

. Prepared for U.S. Environmental Protection Agency. DCN 81

- 202

- 187

- 68

- 14. February 1981.103

from sour ces equipped with wet control devices, and the limited effectiveness of traditional PM control technologies in removing filterable PM 2.5 . Likewise, the commenter noted that EPA is not proposing to base limits on condensable PM. 183

Response: We acknowledge th is comment and appreciate the commenter’s support for continuing to base the emission limits on filterable PM measured with EPA Method 5

.

5.1

- 03 Comment: Commenter 0059 noted that EPA has proposed to require repeat testing at least once every 60 months for PM and TRS. The commenter request ed that, to provide operational flexibility, the testing be required once every 5 calendar years, at any time during the fifth calendar year.

Response: We agree it is reasonable for facilities to have some operational flexibility in when they do the repeat testing and have amended the final rule text to refer to repeat testing every “5

years

. ”

5.1

- 04 Comment: Commenter 0057 stated that the test methods in the proposed rule do not

address instances in which SDT emission vents consist only of a demister pad with no extending

stack. In such situations, the commenter indicated that it is impossible to use a Method 5 probe to accurately dete rmine the PM emission rate. The commenter suggested that the rule be revised to require a stack with a suitable emission point for a Method 5 PM stack test and suitable emission test point for TRS emissions.

The commenter also suggested that EPA state wha t procedures should be used when making a

Method 5 and/or Method 16, 16a, 16b

, or 16c determination during high

- aerosol, relatively low

temperature cond itions in SDTs

.

Response: Section 60.8 of the NSPS General P rovisions specifies performance testing requirements. Section 60.8(e)(1) requires that the owner or operator provide s ampling ports adequate for test meth ods applicable to such facility including: (i) constructing the air pollution control system such that volumetric flow rates and pollutant emi ssion rates can be accurately

determined by applicable test methods and procedures

, and (ii) providing a stack or duct free of cyclonic flow during performance tests, as demonstrated by applicable test methods and procedures. These General P rovisions requi rements address the commenter’s concern regarding SDT demisters with no extending stack.

Regarding the commenter’s concern about testing during periods of high

- aerosol and low

temperature conditions within the SDT, we note that § 60.8(c) , as incorporated i nto subpart BBa and superseded with §60.285a(a), requires that emissions testing be performed under representative operating conditions. We also note that testing is performed at the outlet of the control device (usually a wet scrubber) that would entrain aerosols from the SDT. Method 5 is a widely used method applicable for the determination of PM emissions from stationary sources

, including those controlled by wet scrubbers

. Similarly, Methods 16, 16A, 16B, 16C are applicable for SDT scrubber stacks. The EPA is not aware of any reason why th ese method s could not be applied under the SDT conditions described by the commenter.

183 See 78 FR 31321.104



### 5.2 Parameter Monitoring

5.2

- 01 Comment: Commenter 0056 supported making the monitoring, recordkeeping and reporting requirements more consistent with the current s ubpart MM NESHAP requirements.

Response: We acknowledge the commenter’s support

.

5.2.1 Incinerator Parameter Monitoring

5.2.1

- 01 Comment: Commenter 0055 noted that t he EPA is proposing to allow facilities to omit

5

- minute recorded temperature measurements from the 3

- hour block averages when no TRS emissions are fired and requests comment on the 3

- hour averaging time for incinerator temperature monitoring, especially as it relates to temperature data recording and averaging practices specified for individual mills under the s ubpart S NESHAP. The commenter agree d

with the 5

- minute frequency and the omission of all 5

- minute recorded temperature

measurements from the 3

- hour block averages when no TRS emissions are fired.

Response: We acknowledge the commenter’s support fo r our decision to use a 5

- minute frequency for recording temperature measurements . As proposed, the 5

- minute temperature readings will be used in a 3

- hour block average of the incineration temperature. The 3

- hour block averaging period is consistent with the averaging time many mills use for subpart S NESHAP compliance

.
We also acknowledge the commenter’ s support for omitting the 5

- minute recorded temperature

measurements from the 3

- hour block averages when no TRS emissions are fired. We are finalizing this provision as proposed in order to account for incinerator warm

- up and cool

- down periods before TRS emissions are generated or when an alternative control device is used

.

5.2.1

- 02 Comment: Commenter 0059 stated that t he reference to temperature monitoring for incinerators controlling emissions of BLO systems in §§ 60.284a(b)(1) and 60.287a(b)( 3) should

be removed because NSPS subpart BBa does not require control of black liquor oxidation
systems.

Response: We agree with th e commenter about removing the provisions in §§60.284a(b)(1) and 60.287a(b)(3) that include BLO systems in the list of proc esses for which incinerator temperature monitoring is required. When subpart BB was reviewed in 1983, the requirement to control TRS emissions from BLO systems was rescinded, but BLO systems were erroneously retained in the incinerator temperature monitori ng provision. The same wording including BLO systems was

carried over into the proposed subpart BBa. We have removed mention of BLO systems from § § 60.284a(b)(1) and 60.287a(b)(3) in subpart BBa for the final rule

. We have also removed the definition of BLO system because this term no longer appears in subpart BBa following its removal from § § 60.284a(b)(1) and 60.287a(b)(3 ).

5.2.1

- 03 Comment: Commenter 0059 noted th e following:105

 M ost facilities control TRS emissions from affected digesters, evaporators, BSWs , and condensate strippers by ducting the exhaust gases to a combustion device.

 I f the gases are ducted to a stand

- alone incinerator, temperature monitoring is used to

ensure th e device is operating at a temperature of at least 1200°F.

 I f the gases are ducted to a combustion device such as a lime kiln, recovery furnace, or power boiler, they are injected either with the primary fuel, with the combustion air, or

into the flame zon e , as allowed

.

 T he same emissions control scheme is used for HAP emissions control from these

sources under MACT s ubpart S , which does not require temperature monitoring when the gases are controlled in a lime kiln, recovery furnace, or power boiler

, per § 63.443(d)(4).

Commenter 0059 recommended that EPA make the clarification in NSPS subpart BB a that temperature monitoring is only required when TRS control is achieved in a stand

- alone

incinerator. The commenter cited the 1983 NSPS r eview BID

, which indica ted that there is no need to monitor combustion temperature from devices other than an incinerator because these devices normally operate at temperatures higher than 1200°F. 184

Th e commenter suggested the clarification be made as follows:

§ 60.284a(d)(3)(ii): All 3

- h our block averages during which the combustion temperature at the point of incineration is less than 650°C (1200°F), where the provisions of § 60.283a(a)(1)(iii) apply and an incinerator is used as the combustion device.

§ 60.287a (b)(3) : Records of the incinerator combustion temperature at the point of incineration of effluent gases which are emitted from any digester system, brown stock washer system, multiple effect evaporator system, black liquor oxidation system, or

condensate stripper system where the provisions of § 60.283a(a)(1)(iii) apply and an

incinerator is used as the combustion device.

The commenter support ed EPA’s proposed incinerator temperature monitoring provisions at § 60.284a(c)(2) that require 3

- hour averages for determining compliance status, as this approach is required in MACT s ubpart S.

Response: We agree with the commenter’s suggested changes to § § 60.284a(d)(3)(ii) and 60.287a(b)(3) to clarify that temperature monitoring would not be required for combustion devices such as a lime kiln, recovery furnace, or power boiler, since those devices normally operate at temperatures higher than 1200 ° F. These changes will make the subpart BBa provisions consistent with the monitoring methods mills use to comply with subpart S. Accordingly, we have revised § § 60.284a(d)(3)(ii) and 60.287a(b)(3) in subpart BBa for the final

rule.

184 U.S. Environmental Protection Agency. Review of New Source Performance Standards for Kraft Pulp Mills.

EPA

- 450/3

- 83

- 017

. September 1983 . p. 9

- 2.106

5.2. 2 Recovery Furnace Parameter Monitoring

5.2.2

- 01 Comment: Co mmenter 0055 noted the following from the subpart BBa proposal:

 The EPA is p roposing that ESP secondary voltage and secondary current (or total secondary power) be monitored and averaged over the same calendar quarter as the opacity monitoring allowance.

 The 2 percent opacity monitoring allowance will only be available for recover y furnaces with ESP parameters that are above the minimum limits established during the PM performance test ( i.e. , above the minimum secondary current and secondary voltage or

above minimum total secondary power).

 Subpart BB currently requires that the opa city allowance be calculated based on the percent of the total number of possible contiguous periods of excess emissions in a
quarter.

 The EPA is solicit ing comment on the proposed requirement, specifically whether a semiannual basis would be more appropri ate based on the semiannual reporting requirement.

Commenter 0055 noted that t he previous opacity allowance of 6 percent allowed a maximum of 1,314 contiguous periods of excess emissio ns in a quarter (131.4 hours). According to the

commenter, t he proposed opacity allowance of 2 percent reduces the maximum number of contiguous periods of excess emissions to 438 per quarter (43.8 hours). The commenter stated

that t his is consistent with data accumulated by the EPA, and tightens the limitations without

undue burden so long as the current SSM exemption is maintained. The commenter noted that

i ndustry has concerns that by removing the current SSM exemption, it would be difficult to meet the proposed 2 percent allowance. The commenter has determined that a semian nual basis for this requirement would not result in an increase in emissions, but would decrease the opport unity for reported violations. According to the commenter, t his alleviates some of the burden on the industry without harming the environment. Theref ore, the commenter support ed the semiannual basis for the opacity allowance.

The commenter stated that sources using a COMS should not be required to conduct parametric monitoring for the ESP. In addition, the commenter stated that sources should be allo wed to use alternative methods of compliance in lieu of the specified parametric monitoring requirements as proposed. As an example, the commenter suggested that facilities could correlate opacity to PM emissions and then monitor the opacity to show compli ance with the PM standards. Th e commenter noted that th is is a similar approach to that used in CAM plans approved under 40 CFR p art 64.

Response: We acknowledge the commenter’s support for using a semiannual basis to determine the opacity allowance

. As mentioned previously, EPA is promulgating a semiannual basis for calculation of monitoring allowances consistent with the semiannual reporting requirement in §60.28 8 a(a).

Regarding the commenter’s statement that sources using COMS should not be require d to conduct ESP parameter monitoring, we proposed ESP parameter monitoring in addition to107

COMS use to enable affected units to show continuous compliance with the PM concentration standards at all times, including periods when the opacity monitoring allow ance is u sed. As

discussed in section 4.1 of this document, the EPA has included language in subpart BBa to clarify that the standards apply at all times as specified in the §§60.284a and 60.285a monitoring and testing provisions in the rule . The ESP monit oring requirements were added to provide a measure of continuous compliance in order to enable retention of an opacity monitoring

allowance in the NSPS

. The 2 percent opacity monitoring allowance will only be available for recovery furnaces with ESP parame ters that are above the minimum limits established during the PM performance test ( i.e. , above the minimum secondary current and secondary voltage or above minimum total secondary power).

Regarding the commenter’s request that sources be allowed to use alternative methods of compliance in lieu of the proposed paramet r ic monitoring requirements, it should be noted that sources are allowed to request alternative monitoring requirements under 40 CFR 60.13(i).

5.2.2

- 02 Comment: Commenter 0055 noted the following from the subpart BBa proposal:

 The EPA is proposing to require ESP and wet scrubber parameter monitoring for recovery furnaces equipped with an ESP followed by a wet scrubber because opa city is not a suitable monitoring requirement for recovery fur naces with wet scrubber stacks.

 The EPA is specifying that the scrubber parameters would be measured and recorded at least once every 15 minutes and these 15

- minute measurements used to ca lculat e 12

- hour block averages.

 The EPA is reque sting comment on the use of parameter monitoring instead of opacity monitoring in systems that utilize both an ESP and a wet scrubber.

 The EPA is also requesting comment on the parameter recording frequency and

ave raging time for ESP parameters and wet scrubber parameters.

Commenter 0055 requested that EPA clarify whether a source controlled by an ESP/scrubber combination is relieved from meeting the 20 percent opacity requirement. The commenter a lso requested that EPA clarify if it is EPA ’ s intention to relieve a recovery furnace controlled solely by a scrubber from the 20 percent opacity requirement.

Commenter 0055 believes that the use of a scrubber, either solely or in combination with an ESP,

should relieve the source from the 20 percent opacity requirement. T he commenter agreed with the use of paramet r ic monitoring in lieu of opacity monitoring. The commenter concurred with the proposed parametric monitoring and recording on the ESP and wet scrubber every 15

minutes , and the 12

- hour block averaging time for ESP parameters and wet scrubber parameters.

However, the commenter believes that sources should be allowed to use alte rn ative methods in lieu of the specified parametric monitoring requirements as propose d using an approach similar to that used in CAM plans approved under 40 CFR part 64. According to the commenter, t he

TRS C EMS would demonstrate that the scrubber is working properly and would preclude the need to do parametric monitoring for the scrubber.

Response: Recovery furnaces with either a scrubber alone or an ESP/scrubber combination

control are not required to monitor opacity. Section 60.282a(a)(1)(ii) and (a) (2)(ii) clarify that108

the opacity limit only applies for recovery furnaces with ESP controls. Section 60.284a(b) specifies wet scrubber parameter monitoring requirements for recovery furnaces, and § 60.284a(b)(4) of subpart BBa states that opacity monitoring is not required for ESP/scrubber

combination controls.

We acknowledge the commenter’s support for the proposed 15

- minute recording frequency and

12

- hour block averaging time for recovery furnace ESP and scrubber parameter monitoring. Regarding the commenter’s request that sou rces be allowed to use alternative methods of compliance in lieu of the proposed parameter monitoring requirements, it should be noted that sources are allowed to request alternative monitoring requirements under 40 CFR 60.13(i).

The commenter suggests tha t TRS CEMS would demonstrate that a scrubber is working properly and would preclude the need to do parametric monitoring for the scrubber . However, we note that TRS emissions are affected by more than scrubber operation alone ( e.g. , process factors play

a role which could potentially be more significant than scrubber operation in reducing TRS emissions). Thus, any alternative monitoring request that TRS CEMS replace scrubber parameter monitoring should contain justification explaining why TRS CEMS would be appropriate.

5.2.2

- 03 Comment: In the event EPA decides to finalize its proposed secondary voltage, secondary current, and alternat iv e secondary power CPMS monitoring requirement for ESPs serving recovery furnaces, commenter s 0056 and 0059 believe that EPA’s rule language at proposed §60.284a(e)(1)(ii) 185 for recovery furnace ESPs should add secondary power as an alternate to secondary voltage and secondary current, similar to its inclusion at proposed §60.284a(e)(1)(iv) for lime kiln ESPs

. 186

Response: We agree with the clarification to subpart BBa provided by the commenter s and have made the suggested change to §60.284a(e)(1)(ii) of the final rule.

5.2.3 Smelt Dissolving Tank Parameter Monitoring

5.2.3

- 01 Comment: Commenter 0055 noted that t he EPA is propos ing a 12

- hour averaging time for wet scrubber parameters recorded at least once every 15 minutes rather than retaining the current NSPS requirement to record wet scrubber parameters only once per shift at SDT s . The

commenter also noted that EPA is s olicit ing comment on the SDT scrubber parameter monitoring requirements, especially the recording frequency and the averaging time for wet scrubber parameters.

The commenter agreed with the proposed SDT scrubber parameter monitoring and recording frequen cy of 15 minutes and the 12

- hour averaging time for wet scrubber parameters. The

commenter also believes that sources should be allowed to use alternative methods of compliance in lieu of the specified parametric monitoring requirements as proposed using a n approach similar to that used in CAM plans approved under 40 CFR p art 64.

Response: We acknowledge the commenter’s support for the proposed 15

- minute frequency and

12

- hour block averaging time for SDT scrubber parameter monitoring. Regarding the

185 See 78 FR 31339

. 186 See 78 FR 31324

.109

comment er’s request that sources be allowed to use alternative methods of compliance in lieu of the proposed parameter monitoring requirements, it should be noted that sources are allowed to request alternative monitoring requirements under 40 CFR 60.13(i).

5.2.3

- 02 Comment: Commenter 0057 argued that the monitoring requirements and test methods for SDTs in the proposed rule are insufficient . As support for this argument, the commenter noted the following:

 SDT vent emissions can increase during recovery furn ace conditions in which there is a temporary loss of combustion on part of the smelt bed at the base of the recovery furnace and subsequent sluicing of such uncombusted material in to the hot SDT

.

 Dimethyl sulfide, dimethyl disulfide and potentially other s ulfur compounds ( i.e. methyl mercaptan, ethyl mercaptan, phenyl mercaptan, etc. ) contained in uncombusted concentrated black liquor can then be carried over on the surface of the smelt bed and conveyed into the SDT

.

 Once in the tank, such organic sulfur co mpounds can boil off as process gas emission s from the SDT

.

The commenter contended that b ecause problems during the operation of recovery furnaces can

influence SDT vent emissions of TRS and other sulfur compounds, continuous TRS monitoring

of such tank vents should be required as part of the continuous monitoring requirements under proposed § 60.284 a . Alternatively, the commenter suggested that continuous parameter monitoring be required for (a ) SDT vent scrubbers to ensure a minimum level of causticity and ( b ) sulfidity of green liquor.

Response: The situation described by the commenter of a temporary loss of combustion on part

of t he recovery furnace smelt bed and discharge of uncombusted concentr ated black liquor in to the SDT is not a normal operating condition, and would be considered a malfunction. Malfunctions are not valid operating conditions for which EPA establishes emissions standards.

The commenter requests that the NSPS require TRS CEMS on SDT stacks, or alternatively parameter monitoring to ensure a minimum level of causticity ( e.g. , pH monitoring) or sulfidity of green liquor

. Regarding the commenter’s suggestion to monitor TRS emissions and sulfidity,

t he BID for the original NSPS stat ed the following:

Since the standard for smelt dissolving tanks is express ed in a format of pollutant mass per unit of production, the gas flow rate and the production rate would have to be measured simultaneously to reduce the TRS concentrations measured by the monitor to units of the proposed standard. Inaccuracies would arise from measuring velocities continuously, and the production rate cannot be measured accurately except over relatively long periods of time. The inaccuracies involved in continuously measuring emissions from the smelt dissolving tank are felt to be sufficiently large that EPA has determined that the direct monitoring of TRS emissions from the smelt dissolving tank is not practical.

Another method exists for continuously monitoring the proper operation of smelt dissolving tanks to ensure that TRS emissions are well controlled. The TRS emissions110

from the smelt dissolving tank are related to the concentration of dissolved sulfides in the smelt dissolving tank water and in the water used in the scrubber. The concentration of the dissolved sulfides could be monitored, but neither EPA nor the industry have experience with this type of monitoring. The proposed standards therefore do not require the monitoring of dissolved sulfides in the smelt dissolving water or the scrubber

water. 187

The concerns noted in the original NSPS BID regarding continuous SDT monitoring remain valid today. The mass per unit production format of the SDT TRS standard has not changed. Sulfidity is not measured directly, bu t is calculated based on the concentration of multiple chemicals in solution which would to be continuously measured individually in order to allow for continuous calculation of sulfidity.

Even if SDT TRS monitoring were practical, the typical TRS emissio ns from SDTs (36 tpy) are too low to make TRS monitoring a cost

- effective monitoring option, compared to typical

uncontrolled TRS emissions from sources that are required to conduct TRS monitoring ( e.g. , 2,700 tpy from recovery furn aces, 144 tpy from lime kilns). Nevertheless, we have strengthened the continuous compliance requirements for SDTs relative to subpart BB

. In addition to specifying a minimum 15

- minute recording time and 12

- hour averaging time for wet scrubber parameters (as opposed to a once

- per

- shift reading), t he NSPS revisions for subpart BBa require

5

- y ea r repeat testing for all NSPS affected sources, which include s TRS tests for SDTs , ensuring ongoing compliance with the SDT TRS limit

.
5.2.4 Lime Kiln Parameter Monitoring

5.2.4

- 01 Comment: Commenter 0055 noted the following from the subpart BBa proposal:

 The EPA is proposing a 12

- hour averaging time for wet scrubber parameters recorded at least once every 15 minutes (instead of the current NSPS requirement to record wet scrubber parameters only once per shift).

 Excess emissions for lime kilns with ESP/scrubber combination controls would be any

12

- hour block ESP or scrubber para meter below its respective site

- specific limit (established during the performance test) during times when lime mud is fired in the kiln.

 The EPA is request ing comment on the 12

- hour averaging time specified for ESP and scrubber parameters, and whether a 3

- hour averaging time (such as that specified under

the s ubpart MM NESHAP for wet scrubber parameters) would be more appropriate and adequately account for periods of process variability in the absence of a monitoring

allowance.

Commenter 0055 agree d with the proposed parametric monitoring and recording frequency of

once every 15 minutes and averaging time of 12 h ou rs. The commenter did not consider the necessity to calculate a 3

- hour average for 40 CFR p art 63, s ubpart MM and a 12

- hour average for this NSPS to constitute an undue burden.

187 U.S. Environmental Protection Agency. Standards Support and Environmen tal Impact Statement Volume 1: Proposed Standards of Performance for Kraft Pulp Mills . Publication No. EPA

- 450/2

- 76

- 014

- a. September 1976.

Section 9.8.111

According to the commenter, compliance with the 3

- hour average would imply complia nce with

the 12

- hour average. The commenter noted that EPA has expressed concern that a 3

- hour average may not account for process variability and recommended that, i f EPA decides to pursue
the 3

- hour averaging time, any violation indicated by the 3

- hour a veraging block be examined

from the 12

- hour averaging standpoint before determining if a violation has occurred.

The commenter also stated that sources should be allowed to use alternative methods of compliance in lieu of the specified parametric monitori ng requirements as proposed using an approach similar to that used in C AM plans approved under 40 CFR p art 64.

Response: W e acknowledge the commenter’s support for the proposed 15

- minute frequency and

12

- hour block averaging time for scrubber parameter monitoring. The final rule retains the 12

- hour averaging time for wet scrubber parameters and ESP parameters (when an ESP is used in combination with a wet scrubber). The commenter is correct that compliance wit h the 3

- hour average would imply compliance with the 12

- hour average. Regarding the commenter’s request that sources be allowed to use alternative methods of compliance in lieu of the proposed parameter monitoring requirements, it should be noted that sour ces are allowed to request alternative monitoring requirements under 40 CFR 60.13(i).

5.2.5 Digester Parameter Monitoring

5.2.5

- 01 Comment: Commenter 0057 argued that t he proposed NSPS do not contain sufficient monitoring requirements to assure compliance with digester emission limitations and TRS control requirements from digester chip bins

. A ccording to the commenter, an operator of a k raft pulp mill using a continuous digester and ha ving the potential to emit digester process gases from chip bins to the atmosphere cannot assure compliance with the proposed TRS emission limitations without monitoring and instrumentation. The commenter recommended that such monitoring should , at the ver y least, include parameter monitoring for chip steaming bin gas pressure and exhaust temperature. The commenter contended that a minimum level of digester process monitoring, recordkeeping and reporting is needed to assure that digester process gases

are n ot released because the operator has maintained below

- atmospheric pressure chip bin steaming conditions.

Response: We address applicability of the NSPS to digester chip bins in response to comment

2.3

- 02 above . Chip bins in which flash /live steam is introduced are part of the digester system, and digester process gases are required to meet the NSPS emission limits for TRS

. In addition to the NSPS emission limits, the subpart S NESHAP contains detailed collection system requirements (see §63. 450

– Standards for enclosures and closed

- vent systems) that further ensure emissions from all digester emission points are routed to a control device. These closed

- vent system standards have been incorporated into the subpart BBa TRS standards. Therefore, we believe it is unnecessary to include parametric monitoring requirements specific to chip bins, which are one component of the digester system, in the NSPS.



### 5.3 TRS CEMS Data O 2 

### Correction Procedure

5.3

- 01 Comment: Commenter 0059 agreed with EPA’s ratio nale in allowing facilities to use

uncorrected TRS concentrations during periods when stack O 2 values are greater than or equal to112

15 percent. According to the commenter, t hese high stack O 2 periods are typically indicative of (a) periods of S/S or (b) tra nsient changes in boiler/lime kiln loading that have not been reflected

in air flows. The commenter stated that the ability to use uncorrected TRS concentrations mitigates the use of an artificially inflated (and inappropriate) O 2 correction factor.

The commenter noted that EPA has, however, limited the applicability of this approach by further stipulating that it can be used only during periods of S/S where the uncorrected TRS concentrations are below applicable limits (5 ppm for recovery furnaces an d 8 ppm for lime kilns). The commenter countered that there are two operating scenarios that are applicable :

1. Periods of S/S where uncorrected TRS concentrations are below the respective upper restriction levels (30 ppm and 22 ppm for recovery furnaces an d lime kilns, respectively)

and stack O 2 concentration is greater than or equal to 15 percent; and

2. Limited normal operating periods where uncorrected TRS concentrations are below the respective upper restriction levels (30 ppm and 22 ppm for recovery furna ces and lime kilns, respectively) and stack O 2 concentration is greater than or equal to 15 percent.

Commenter 0059 noted that EPA conclude d in the COMS/CEMs background document 188 that brief spikes in recovery furnace TRS concentrations ( greater than 5 ppm) occurred during S/S periods and that the proposed upper restriction of 30 ppm adequately encompasses these spikes, after addressing extreme

- value outliers. Noting that spikes greater than 5 ppm do occur during

S/S periods, the commenter concluded t hat it is only logical to allow the use of uncorrected TRS

concentrations for these instances (uncorrected values below upper restriction level AND stack

O 2 greater than or equal to 15 percent ). The commenter stated that t his option would be of

limited use if TRS “limits” (as opposed to “upper restriction levels”) are stipulated as a threshold for applicability.

Commenter 0059 noted that t he scenario identified in Item 2 above (normal operation) also can

occur. Given that EPA is proposing a standard that i ncludes all operating periods, including S/S

, the commenter concluded that EPA should allow the use of this approach for all operating periods when the uncorrected TRS concentration is below the applicable upper restriction level

and stack O 2 greater than or equal to 1 5 percent

.

Response: We acknowledge the commenters’ support for the provision allowing facilities and

enforcement authorities to consider the TRS concentration uncorrected for O 2 when determining compliance with the excess emissions provision s for TRS during periods of S/S when stack O 2 percentage approaches ambient conditions . We are retaining this provision as proposed.

The purpose of O 2 correction is to prevent circumvention of the concentration standards for combustion sources by dilution ( e.g. , through leakage of ambient air in the control device or exhaust ductwork)

. Although the NSPS G eneral P rovisions (§60.12 ) prohibit circumvention of the concentration standards by dilution, it is difficult to distinguish between process air needed

188 U.S. Environmental Protection Agency. Review of Continuous Emission Monitoring and Continuous Opacit y Monitoring Data from the Pulp and Paper Information Collection Request Responses Pertaining to Subpart BB

Sources

. Docket ID. No. EPA

- HQ

- OAR

- 2012

- 0640. April 5, 2013.113

fo r combustion and dilution air. Therefore the O 2 correction provision is needed to correct for

excess air in

- leakage in the outlet stream. 189

The O 2 correction procedure increases the reported TRS concentration when O 2 levels exceed the

correction value of 8 percent or 10 percent for recovery furna ces or lime kilns, respectively

. These O 2 correction values were established when the NSPS were originally promulgated based on analysis of the O 2 concentrations in recovery furnace and lime kiln exhaust streams, and are still representative today. Table 4 below provides some examples for a lime kiln to help illustrate this point.

Table 4 . Example Lime K iln O 2 C orrections

Measured TRS ppm (limit f

or lime kilns) Measured

O 2 % TRS ppm

corrected to
10% O 2 Note

5 6 3.7 O 2 levels lower than the 10% correction standard reduce the corrected TRS ppm. Dilution is not suspected.

5 10 5 There is no change to the reported TRS ppm when

measured O 2 equals the O 2 correction value (10%)

5 15 9.2 Higher O 2 , potentially from dilution during normal operation, increases the corrected TRS ppm

. 5 20 55 Very high O 2 levels

, possibly symptomatic of excessive dilution under normal operation, malfunction, or transient O 2 levels under S/S

conditions

, inflate the TRS ppm

. 5 20.9 550

O 2 correction equation: Corrected ppm = Measured ppm x (21

- 10)/(21

- measured O 2 )

The proposed rule language to allow otherwise compliant uncorrected TRS concentration s (5 ppm and 8 ppm f

or recovery furnaces and lime kilns, respectively) to be considered when

stack O 2 percentage approaches ambient conditions was limited to periods of S/S because in some cases the stack gas O 2 percentage may not be stable during these times and could approach

ambient levels if combustion conditions do not consume the O 2 in the process air. We disagree that the 30 ppm and 22 ppm upper limits are appropri ate values to represent the uncorrected TRS concentrations because the 30 ppm and 22 ppm upper limits were derived from analysis of O 2 - corrected values. We also disagree that extending the provision to normal operations is appropriate because this would co ntradict the purpose of O 2 correction to prevent dilution.

We believe the rule, as proposed, provides ample flexibility. In addition to allowing facilities to dismiss otherwise compliant TRS values inflated by the O 2 correction equation during S/S

, monitoring is based on a 12

- hour averaging period that works to smooth out variability in the hourly TRS and O 2 measurements during all time periods. We further note that removal of periods in which no BLS or lime mud is processed through the recovery furn ace or lime kiln,

189 U.S. Environmental Protection Agency. Standards Support and Environmental Impact Stat ement Volume 1: Proposed Standards of Performance for Kraft Pulp Mills . Publication No. EPA

- 450/2

- 76

- 014

- a. September 1976. Chapter 9.114

respectively, also addresses times when O 2 levels may be high due to changing combustion

conditions.

5.3

- 02 Comment: Commenter 0059 requested clarification on the procedure used to calculate

the 12

- hour corrected TRS concentrations used t o demonstrate compliance with (a) the applicable TRS limits and (b) the applicable “upper restriction level” during periods when the monitoring allowance is invoked. The commenter noted that the need to consider uncorrected TRS concentrations during periods when stack O 2 levels are greater than or equal to 15 percent is another reason for requesting this clarification.

According to commenter 0059, t he currently proposed procedure in §60.284a(c)( 1) involves (a) calculating the 12

- hour uncorrected TRS concentrations, (b) calculating the corresponding

12

- hour O 2 concentrations, and (c) carrying out the O 2 correction on the 12

- hour average. Commenter 0059 noted that §60.284(e)(3) states that “If the measured TRS concentration

uncorrected for O 2 is less than the applicable.....during periods of startup or shutdown when the

stack O 2 concentration is 15 percent or greater, then the Administrator will consider the TRS average to be in compliance.” A ccording to commenter 0059 , a procedure that performs the O 2 correction on 1

- hour uncorrected TRS data, and subsequently uses hourly corrected values to

calculate the 12

- hour average may be more appropriate given this new O 2 correction requirement. Commenter 0056 concurred that EPA needed to consider a procedure for incorporating uncorrected TRS values in support of the proposed policy of using uncorrected

data when stack O 2 concentration approaches ambient levels. C ommenter s 0056 and 0059

recommended that EPA use the following procedure developed by commenter 0058 for calculating the corrected 12

- hour TRS concentrations:

1. Compute 1

- hour averages of uncorrected TRS concentrations ; 2. Calculate the 1

- hour averages of stack O 2 concentrations ; 3. Skip to step 5 if the uncor rected 1

- hour average TRS concentration is less than the applicable TRS limit 190 AND the 1

- hour stack O 2 greater than or equal to 15 percent ; 4. Carry

- out the O 2 correction according to equation in §60.2 84a(c)(1)(iii), if the 1

- hour

stack O 2 is less than 15 percent to obtain the corrected 1

- hour TRS concentration ; skip to step 6;

5. Use uncorrected 1

- hour TRS concentration to ca lculate the 12

- hour block average;

6. Repeat steps 1 through 5 for each h ourly average in the 12

- hour block; and

7. Roll

- up t he hourly averages to calculate the 12

- hour block average concentration.

According to commenter 0059, t he procedure outlined above w ould help streamline the calculations required to demonstrate compliance with the 12

- hour block average TRS standard,

while accommodating the need to comply with upper restriction levels and the need to use

uncorrected TRS values in certain instances. T he commenter suggested that t his procedure could

be added as an option in § 60.284(c)(1).

Response: We are not adopting the co mmenter’s calculation procedure. It was not EPA’s intention to completely overhaul the longstanding NSPS TRS and O 2 data reduction procedures with the proposed rule. As the commenter notes, the data reduction procedure in the rule

190 Commenter 0059 proposed that EPA modify this to the TRS upper restriction level

.115

involves computing 1

- hour TRS and O 2 values from valid monitoring data, and then av eraging

the 1

- hour values to arrive at 12

- hour TRS and O 2 values. The O 2 correction is performed using

the 12

- h ou r averages for TRS and O 2 to arrive at each 12

- hour block O 2 - corrected TRS concentration that is either characterized as a compliant 12

- hour block or as a 12

- hour block period of excess emissions. Next, the total number of possible contiguous 12

- hour blocks in the semiannual reporting period is compared with the number of 12

- hour blocks that are excess emissions to calculate the monitoring allowance and determine if a violation of the standards has occurred. The intent of the proposed rule was not to significantly alter the fundamental data reduction procedure, but to insert some additional criteria for defining invalid data and characterizing 12

- hour blocks considered to be excess emissions or violations

. See also our
response to comment 5.4

- 01 for reasons why we chose not to use a shorter averaging time

. We clarify the key steps in the data reduction procedure below and have added the words “12

- hour”

or “12

- hour average” to the final rule to clarify when the 12

- hour block average is used for a particular calculation.

Step 1. Removing invalid data and calculating the 12

- hour average

. Sections 60.284a (c) (5)

- (7) require operation of TRS CEMS to collect data at all required intervals at all times the affected facility is operating

, except for periods of monitoring system malfunctions or out

- of

- control periods, repairs associated with monitoring system malfunctions or out

- of

- control periods, and required monitoring system quality assurance or quality control activities including, as applicable, calibration checks and required zero and span adjustments

. D ata recorded during monitoring system malfunctions or out

- of

- control periods, repairs associated with monitoring system malfunctions or out

- of

- control periods, or required monitoring s ystem quality assurance

or control activities are considered invalid data . Invalid data may not be used in calculation s, such as the 1

- hour average values rolled into the 12

- hour block average TRS and O 2 calculations required under § 60.284a (c)(1).

Followi ng removal of invalid data as described in § § 60.284a (c) ( 5)

- (7), the 12

- hour block averages of TRS and O 2 are calculated and subsequently used to calculate the 12

- hour O 2 - corrected TRS concentration following the procedures in § § 60.284a(c ) (1) (i)

- (iii)

.

Step 2. Determining which 12

- hour blocks are e xcess emissions

. Next, each O 2 - corrected

12

- hour block average is evaluated to determine if it is (1) a compliant block, or (2) an excess emissions block. Excess emissions from recovery furnaces and lime kilns are defined as all

12

- hour block averages above the TRS ppm limit corrected for O 2 when BLS or lime mud is

fired. Thus, 12

- hour blocks during which no (zero) BLS or lime mud is fired are not considered

to be excess emissions even if the TRS concentration i s higher than the applicable 5 or 8 ppm limit ( possibly because of startup or shutdown conditions contributing to near

- ambient O 2 )

. We recognize that some 12

- hour blocks may only include a brief time wh en BLS or lime mud was

fired. As noted in our response to comment 5.4

- 03 , such blocks were included in the data sets

used to reevaluate the TRS standards , and

, therefore

, are appropriate for evaluation as compliant

or excess emissions blocks

.

While subpart BBa does not specify rigorous procedures for monitoring and averaging of BLS and lime mud throughput data , we note that production monitoring data are readily available and

are required under subpart MM. Mills are expected to match the available production data with116

the 12

- hour block T RS averages for purposes of identifying 12

- hour blocks in which there was zero throughput

. Furthermore, §60. 7(b) requires recordkeeping of startup and shutdown periods

, which will aid in identifying 12

- hour periods of zero throughput.

Step 3. Determining whether excess emissions are in violation of the standard

. Excess emissions and violations are determined using the 12

- hour block averages. Excess emissions are not considered to be violations if good air pollution practices are used (per §60.284a( e)(2)) and the
percent age of the total number of possible contiguous periods of excess emissions in the semiannual period does not exceed:

 One percent for TRS emissions from straight recovery furnaces, provided that the

12

- hour average TRS concentration d oes not exceed 30 ppm corrected to 8 percent O 2

. (§60.284a(e)(1)(i))

 One percent for TRS emissions from lime kilns, provided that the 12

- hour average TRS concentration does not exceed 22 ppm corrected to 10 percent O 2

. (§60.284a(e)(1)(ii))

Except as provided in §60.284a(e)(3), all O 2 - corrected 12

- hour average TRS concentrations that exceed the upper TRS limits (22 ppm for lime kilns and 30 ppm for straight recovery furnaces) are considered to be violations. In addition, if the 1 percent monitor ing all owance is exceeded,

then other 12

- hour periods of excess emissions would also be considered in violation of the

standards.

Section 60.284a(e)(3) states that the 12

- hour average TRS concentration uncorrected for O 2 may be considered when determining compliance with the excess emissions provisions during periods of startup or shutdown when stack O 2 percentage approaches ambient conditions. If the 12

- hour

average TRS concentration uncorrected for O 2 is less than the ap plicable limit (5 ppm for recovery furnaces or 8 ppm for lime kilns) during periods of startup or shutdown when the

12

- hour stack O 2 concentration is 15 percent or greater, then the Administrator will consider the TRS average to be in compliance. This prov ision only applies during periods of affected facility startup and shutdown.

Given the multiple nested criteria in § 60.284a(e)(3)

– that they only appl y during S /S, that

uncorrected TRS must not exceed 5 or 8 ppm , and that O 2 must exceed 15 percent

– the provision was not intended to be programmed into DAS, but instead was intended to provide mills and enforcement personnel with some recourse should the O 2 correction requirement during S/S be the only reason a violation would have been reco rded. It is expected that mills exceeding the

1 percent monitoring allowance would carefully review their TRS CEMS data in order to explain

violation s to enforcement personnel. During this review, the monitoring allowance could be recalculated following re moval of any blocks meeting all of the conditions in § 60.284a(e)(3) to
determine if it still exceeds 1 percent

.

While it was not EPA’s intent that extensive reprogramming of DAS be completed in order to comply with the subpart BBa standards, mills a re free to program their software as they choose

, if they wish to incorporate § 60.284a(e)(3) into the programming logic

, as opposed to using this provision as an after

- the

- fact consideration should they exceed the 1 percent monitoring117

allowance

. It is expecte d that some reprogramming of DAS would be helpful to address the 22 and 30 ppm upper limits.

5.3

- 03 Comment: Commenters 0056, 0058, and 0059 requested that EPA clarify the procedure

for the reporting and treatment of uncorrected TRS concentrations that ex ceed the span value (30 ppmdv) for the TRS CEMS instrument. One approach that the commenters suggested was to (a)

allow the use of uncorrected TRS measurements for readings up to 60 ppmdv (2 times the instrument span) for calculating the 1

- hour uncorrected averages and (b) for those measurements greater than 60 ppm dv, require the use of 60 ppm dv in averaging calculations. According to the

commenters, t his approach minimizes the use of extreme

- value data that typically have high

levels of measure ment uncertainty

.

Response: When a CEMS reads between the calibrated span and instrument range, the value s the CEMS reads should be used in the emissions average calculation. While th ese data fall

outsi de a calibrated instrument span , we recognize that th e data ha ve value and must be included in any CEMS hourly average or other long

- term rolling average calculation

. Otherwise, facilities could inappropriately dismiss non

- compliant values as invalid data. Additional language has

been added to the final rule in §60.284a(a)(2) to state that the range of the continuous monitoring system must encompass all expected concentration values, including the zero and span values

used for calibration.

When a CEMS reads above the instrument range, the instrument range value should be used in the emissions average calculation. Where an instrument signal output has “flat lined” because it has reached its maximum signal, that value must be included in any CEMS hourly average or other long

- term rolling average calculation. In this case, the source would need to flag these data so that the enforcement agency knows they are likely biased low and the agency can develop an appropriate response ( e.g. , consider if the facility should increase the range of their instrument).

5.3

- 0 4 Comment: Commenter 0059 recommended that EPA make the following editorial changes to T RS and O 2 m onitoring :

 U nder § 60.284a(c)(1)(ii)

, change the cross

- reference from “paragraph (c)(1) of this section” to “paragraph (c)(1)(i) of this section.”

 U nder § 60.284a(c)(1)(iii) , revise the definition of the C

meas term as follows : C meas = the

measured 12

- h ou r average concentration uncorrected for O 2

.

 Under § 60. 2 84a(e) (1) (i) and (iii) , provide clarification to indicate a “12

- h ou r average”

TRS concentration.

Response: We agree with the clarifications to subpart BBa provided by the commenter and have made the suggested changes to subpart BBa for the final rule.



### 5.4 Averaging Times

5.4

- 01 Comment: Commenter 0057 recommended that the k raft pulp mill NSPS be revised to require rolling averages over shorter intervals, or

, at a minimum

, reporting of 12

- hour block averages each hour. The commenter noted that the proposed TRS standard retains 12

- hour block averaging times, which , according to th e commenter, allows excursions from the TRS standard118

to occur. The commenter contended that under the proposed rule, instances of elevated emissions could be avoided by cherry picking which 12

- hour block is reported.

Commenter 0057 indicated that the use of 12

- hour block averages appears to be based on technology from the 1970s when the NSPS were first promulgated, but stated that current technology makes possible both the ability to average over shorter intervals and to use rolling

averages. The commenter pointed out that, w hen the kraft pulp mill NSPS were first proposed in 1976, TRS emission limitations for the digester process group, lime kilns

, and recovery furnaces were all proposed as 4

- hour averages for purposes of emission limitation, compliance evaluation

, and monitoring /

recordkeeping/reporting data integration. 191 The commenter noted that the final NSPS, however, included a less stringent TRS standard and required only 12

- hour block averaging. 192

While not explained, the commenter indicated that th is decision seems to reflect a concern that pulp mills existing at the time would have been unable to comply with more stringent requirements. According to the commenter, n one of the subsequent rulemakings has justified the

12

- hour averaging times or provi ded any review or consideration of shorter averaging times for

TRS emissions. The commenter further noted that EPA generally does not provide for such long

12

- hour averaging times in the NSPS for other sources. The commenter concluded that EPA, a t a
minimu m, must explain why shorter averaging times have been rejected.

Response: The EPA disagrees that block averages allow for cherry picking data to avoid reporting elevated emissions. Block averages are fixed averaging periods ( e.g. , 12 midnight to

12 noon and 12 noon to 12 midnight ) and will include periods of elevated emissions.

The majority of mills are using 12

- hour block averaging times for their TRS monitors and have

12

- h ou r averaging times written into their state permits. Data from 12

- hour average data sets for most mills in the U.S. were analyzed for the NSPS review and used to reevaluate the TRS emission limit and monitoring allowances. In order to review the NSPS TRS limit, it was necessary to compare 12

- hour average data to the NSPS limit

, whic h is currently enforced on a

12

- hour average. T o deviate from a 12

- hour averaging time would require reconsideration of the TRS concentration limit ( e.g. , reducing the averaging time could necessitate increasing the TRS concentration limit). The record keep ing requirements of 12

- hour TRS averages reflect the majority of the data analyzed and the compliance requirements by the state enforcement

authorities , and

, therefore

, were retained for the final rule

. Stack testing (which does not involve

12

- hour averages) is also used in addition to TRS monitoring for enforcement purposes

, as explained in our response to the comment below.

5.4

- 02 Comment: Commenter 0057 requested that EPA c larify h ow to evaluate stack test reports

for p urposes of TRS c ompliance d eterminations

. The commenter stated that EPA’s proposed rule does not explain or indicate how and whether TRS test method run results will be evaluated in order to determine compliance with a 12

- hour average TRS emission limitation. According to the

191 Kraft Pulp Mills Standards of Performance for New Stationary So urces, Proposed Rule, 41 FR 42012, 42016 (Sept. 24, 1976).

192 Kraft Pulp Mills Standards of Performance for New Stationary Sources , Final Rule, 43 FR 7568 (Feb. 23, 1978).119

comme nter, t he proposed rule at §60.285a(d) contemplates Method 16 (or related TRS approved determination method) runs in which “[t]he sampling time must be at least 3 hours, but no longer

than 6 hours.” The c ommenter 0057 stated that, w hile the 5

- y ea r interval s on compliance stack testing are shown as performance tests, there is no explanation, method or narrative in the proposed rule that explains how to make a determination of compliance with a 12

- hour TRS

emission limitation on the basis of a 3 to 6

- hour sam pling time using EPA Method s 16 through 16c testing.

Response: Stack testing and continuous emissions monitoring are two separate and independent methods for determining compliance with the TRS emission limits. Stack testing is used to determine initial compliance, and is repeated in 5

- y ea r intervals as one method of determining

continuous compliance. Continuous monitoring of TRS emissions is also u sed by the regulating

authorities to determine continuous compliance and e xcess emissions

, with data averaged and

r eported on a 12

- hour basis. The stack test uses Method 16, 16A, 16B

, or 16C

, in which t hree

test runs with samplin g times of 3 to 6 hours are averaged together for one emission value to determine compliance

. The data from stack tests may be compared to continuous monitoring data, but are not averaged or intermingled with the CEMS data. The stack test and the CEMS

12

- h ou r averages are both used to demonstrate compliance, but are used individually.

5.4

- 0 3 Comment : Commenter 0059 noted that the proposed rule requires calculation of 12

- hour block average TRS concentrations for the two consecutive periods of each operating day and 3

- hour block averages for several parameters. The commenter further noted that m onitoring is not required during S/S of affected sources when TRS gases are not being fired in an incinerator, when black liquor is not being fired in a recovery furnace, or when lim e mud is not being fired in

a lime kiln. For purpos es of demonstrating compliance, the commenter noted the following

concerns :

 T hese 12

- hour and 3

- hour block average “periods” are fixed (12 midnight to 12 noon and

vice versa), i.e. , the start of the 12

- hou r block does not c oincide with equipment startup.

 F acilities need flexibility to be able to S/S in line with process demands.

 I f a recovery furnace is starting up and begins firing black liquor at 11:0 0, there is only

1 h ou r of data that will be used to calculate the 12

- hour bl ock average TRS concentration.

 I f the operation is not stable

, such that TRS emissions are below 5 ppm, that 1 operating

h ou r will result in excess emissions for that 12

- hour avera ge.

 Similarly, if a source starts up at 12:00, begin s firing BLS or lime mud, and then operators need to sh ut the source down within an h ou r or 2 because operations are not stable and emissions are greater than 5 ppm, 1 operating h ou r will result in excess

emissions for that 12

- hour average.

Commenter 0059 stated that, b ecause EPA has proposed to apply the standards at all times, sources will no longer be able to rely on the NSPS General Provisions to excuse excess emissions during periods of SSM. Therefore, to address these situations, the commenter

recomm ended that EPA establish that a 12

- hour TRS block average must contain at least 8 h ou rs of data and a 3

- hour block average temperature must contain at least 2 h ou rs of data.

Response: For the reasons below

, we are denying the commenter ’ s request for a minimum data availability requirement for TRS and temperature monitoring under the NSPS.120

First, we point out that monitoring requirements do not affect a mill’s ability to start up and shut

dow n in line with process demands. It is not expected that process equipment S/S periods are to coincide with the block averaging periods under the NSPS.

Second, we would like to address any confusion about when monitoring is required. Contrary to
the commenters statement that “ [m] onitoring is not required during S/S of affected sources when TRS gases are not being fired in an incinerator, when black liquor is not being fired in a recovery furnace, or when lime mud is not being fired in a lime kiln, ” we point out that monitoring is required during these times . The mon itoring data required to be collected during

these times are considered specially : (a) when calculating the 3

- hour average incinerator temperature, or (b) in the assessment of which monitoring data constitute excess emissions (zero production periods)

. Mon itoring is required during S/S . Section 60.284a(c ) (5) through (7) requires continuous monitoring systems to collect data at all times the affected facility is operating except for periods of monitoring system malfunctions or out

- of

- control periods, repairs associated with monitoring system malfunctions or out

- of

- control periods, and required monitoring system QA or QC activities including, as applicable, calibration checks and required zero and span adjustments. These monitor downtime and QA periods are to be excluded from calculations used to report emissions or operating limits . Otherwise, f ailure to collect required data is a deviation of the monitoring requirements

.
Taken together, several aspects of the monitoring requirements combine to provide significant flexibility for mills in their efforts to demonstrate compliance with the standard. We discuss

several below.

Rather than specifying that entire block averages be discarded if they do not meet a minimum data availability requirement ( e.g. , the 8 h ou rs per 12

- hour block, or 2 h ou rs per 3

- hour block suggested by the commenter) , t he provisions in § 60.284a(c ) (5) through (7) maximize the number of recorded readings that are included in block averages, and increase the number of block averages acqui r ed over each semiannual period . Maximizing the number of recording readings and block averages over the semiannual period is a more robust approach to mo nitoring, particularly for subpart BBa , which contain s monitoring allowances and r elatively long averaging periods for TRS and most operating parameter limits. Temperature is the only operating parameter limit for which a 3

- hour block average is required (based on at least 36 readings recorded every 5 minutes or less ). The ESP and scrubber operating p arameter limits are

based on a 12

- hour block average (comprised of at least 48 readings recorded in 15

- minute

intervals or less ). E lectrostatic precipitator parameters monitored in conjunction with opacity are based on a semiannual average ( e.g. , over 17,0 00 readings)

.

The TRS data analyzed by EPA to reevaluate the NSPS included S/S periods occurring at varying times in relation to the 12

- hour block average TRS data. The data set analyzed by EPA

included situations w h ere positive process throughput was only reported for 1 h ou r of the 12

- hour block TRS calculation. Such 12

- hour block periods were retained in the data set and considered in the evaluation of the monitoring allowance. Twelve

- hour block averages calculated

with less than 12 h ou rs of data do n ot automatically render the 1 2

- hour block in violation of the applicable TRS concentration limit. In order for a violation to occur

, the emission limit first must121

be exceeded, and then the 1 percen t semiannual monitoring allowance must also be exceeded. 193

A s mentioned by the commenter

, 12

- hour blocks characterized as zero

- throughput blocks would

not be considered as excess emissions. Also, under §60.284a(e)(3)

, otherwise

- compliant blocks

where the 12

- hour O 2 - corrected TRS emissions exceed the limit solely because the O 2 percentage exceeded 15 percent during S/S periods

, would be considered compliant.

Section 60.284a(c ) (2) states that t emperature measurements recorded when no TRS emissions

are fired in the i ncinerator ( e.g. , during incinerator warm

- up and cool

- down periods when no TRS emissions are generated or an alte rnative control device is used) may be omitted from the block average calculation. Thus temperature is recorded during incinerator warm

- up and cool

down, but is not used in the 3

- hour block average calculation when TRS emissions are not fired in the incinerator. Given this requirement and the requirement to exclude monitor downtime and QA periods from calculations of the 3

- hour block average, we recognize that some 3

- hour blocks will be comprised of less than 3 h ou rs of valid data. Addition of a minimum data availability requirement for temperature monitoring would serve to omit 3

- hour block averages from consideration for compliance purposes when TRS emissions are fired into the incinerator for a portion of the block. Use of less than 3 h ou rs of data does not automatically render a block out of compliance with the 120 0°F incinerator te mperature operating limit. Incineration devices used to combust vent gas streams containing TRS are also used to comply with NESHAP s ubpart S

, which requires a higher temperature (160 0°F ) for the incineration of HAP. Incineration devices are usually brough t up to the required incineration temperature prior to accepting vent gases containing TRS or HAP for safety reasons , and backup controls may be used in the interim. It is very unlikely that TRS emissions would be fired into an incinerator when the combust ion temperature is less than 120 0°F , even for a partial block comprised of less than 3 h ou rs of data.



### 5.5 Electronic Reporting

5.5

- 01 Comment: Commenter 0059 argued that EPA has included a new reporting requirement in proposed subpart BB a that was not ju stified and w ould be excessively burdensome to industry. The commenter cited proposed §60.288a(b) and (c), which state that, within 60 days of completing each performance test and CEMS performance evaluation test, the owner/operator

must submit the test da ta to the EPA’s CDX by using the ERT

, when the data and methods are compatible with the ERT.

Commenter 0059 pointed out that f acilities are already required to submit performance test data to regulatory agencies and provide certifications on their semiannual compliance reports that they have performed the required monitoring and will provide information on any deviations from the testing requirements. A ccording to the commenter, a dditional performance test report submittals to EPA provide no useful purpose, environmental or otherwise, and would be an additional administrative burden on operating facilities. The commenter stated that ERT continues to be revised and updated due to various flaws. The commenter argued that i t would be unreasonable to put sources at risk of violations (late reporting) because of EPA reporting tool issues or availability. As an example, the commenter noted that the CDX system went down on

193 Note however that 12

- hour block averages exceeding the applicable ppm upper violation limits (e.g., 30 ppm for straight recovery furnaces, 22 ppm for lime kilns) are automatic violations unless the 12

- hour block met the criteria in §60.284a(e)(3).122

July 1, 2013, the due date for TRI reports

, and that many facilities were unable to su bmit reports electronically until July 2.

Commenter 0059 noted that a number of states already specify that performance test results be

submitted in an electronic format. The commenter requested that EPA remove its reporting format requirement from the ru le 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 that is not problematic and l abor

- intensive for data entry. The commenter contended

t hat, a s proposed, the rule’s ERT requirement is an extra, excessive burden for mills and stack testing vendors. The commenter concluded that EPA needs to defer any electronic collection of data until the CDX system is fully functional, user

- friendly, and s treamlined with s tates.

Response: The EPA acknowledges that there may be existing reporting programs in place. However, the compliance test reporting requirement in this rule allow s for quick and easy access of the data by state, local, and tribal entitie s, 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 wer e 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 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 AIRS/AFS and expect to replace manually entered

information with el ectronic 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 pri or to establishing the requirement for regulated sources to submit compliance data electronically.



### 5.6 Other Testing and Monitoring Comments

5.6

- 01 Comment: Commenter 0056 was concerned that, with this proposal, EPA has reduced or

eliminated the compliance margin and increased the complexity of the NSPS. The c ommenter stated that the proposed incremental changes in surrogate (opacity for PM) and parametric monitoring requirements, in excess emissions monitoring allowances, an d in exemptions during SSM periods unnecessarily reduces or eliminates the compliance margin for future new,

reconstructed or modified facilities. According to the commenter, m onitoring allowances and SSM exemptions were built into the current NSPS based on the large, complex a nd multifaceted

processes. The commenter pointed out that e xisting facilities have worked to achieve compliance margins that take into account these allowances and exemptions because they are necessary to maintain and assure compliance and provide operatin g flexibility. The commenter expected that

f uture facilities will have the same concerns, but noted that EPA has not really identified new

cost

- effective technology to rebuild those margins. The commenter also noted that, while this is a technology

- based r eview, there are no new identified health risks , and, as EPA has noted

, no major pollutant reductions. 194 T hus, the commenter concluded that this proposal may severely narrow compliance margins for new, reconstructed or modified units, adding significant cos t and reducing operating flexibility of those units without improving emissions or reducing health risk.

194 See 78 FR 31332

.123

According to the commenter, e xamples of going beyond the NESHAP s ubpart MM are the proposals to:

 R educe the opacity limit for modified recovery furnaces from 35 percent to 20 percent ;

 R educe the monitoring allowance for opacity from 6 percent of the monitoring periods during a quarter while excluding SSM periods, to 2 percent of the monitoring periods while including SSM periods;

 Require CPMS moni toring and establishing operating limits of secondary voltage and secondary current of each ESP field serving a recovery furnaces and lime kiln where opacity already is monitored 195 and then using the CPMS measurements to potentially

eliminate the ability to use the monitoring allowance, and;

 S ubstitute the current use of CPMS measurements that fall outside of established operating limits as deviations warranting corrective actions (which if not corrected and

exceed certain limits becomes an excess emission u nder the NESHAP), to instead define them immediately as excess emissions subject to enforcement whether or not an actual emission limit for a concentration regulated parameter (PM, TRS) has been exceeded. 196

The commenter noted that c urrent NSPS and NESHAP and rules applicable to pulp mill systems are complex enough that it is sometimes difficult to manage all the compliance requirements, even for sophisticated and dedicated staff at advanced companies. A ccording to the commenter,

a s the standards are appli ed through SIPS by states and other authorities, differing approaches emerge that further challenge standardized compliance efforts. To illustrate the problem, the commenter provided an example

. W ith operations in multiple states , the commenter’s company

h as observed state

- by

- state differences in current monitoring and reporting practices, and even

within state s, differences among mills, with facilities considering the pros and cons of including or excluding monitor downtimes or QA/QC adjustment periods or even including SSM period emissions when they could legally be excluded from compliance calculations. The commenter explained that f

acilities do this because the effort to separate reportable values during normal monitor operating periods from monitor down times or SSM periods is vie wed as excessively burdensome. The commenter noted that, i n some cases
, states require facilities to include non

normal periods in reports of monitoring data. By doing this approach, the commenter said monitoring and reporting bu rdens are reduced

, while emissions during SSM periods are conservatively included when they otherwise could be exempt. The commenter noted that a ir pollution control systems and processes have been developed to establish compliance margin to accomplish thi s.

The commenter stated that the incremental and multiple monitoring additions, 197 the setting of CPMS operating limits as enforceable excess emissions points instead of corrective action triggers, and reduced monitoring allowances converge to make th e proposed kraft pulp m ill NSPS more complex, rather than achieving regulatory flexibility and consistency with current NESHAP and other regulations. The commenter requested that EPA address the additional complexities it is proposing, and

, at a minimum

, re

- evaluate the potentially flawed analyses, as

195 S ee proposed §63.284a(b)(3) and (b)(4 ).

196 See NESHAP s ubpart MM §63.864(k) v. propose d NSPS subpart BBa §60.284a(d) and (e).

197 Such as the proposed ramp

- up in opacity restrictions, to which EPA also adds ESP secondary voltage and current monitoring and operating limits as “another indicator o f ESP performance” [78 FR 31324]) .124

identified by commenter 0058 , that EPA used to develop its proposals to increase restrictions. As a partial solution, commenter 0056 believes re

- proposing a more equitable set of monitoring

allowances would sub stantially alleviate many of these concerns.

Response: In support of their comments on compliance margin and rule complexity, the commenter refers to four changes from subpart BB:

 Reduction in opacity limit;

 Additional ESP monitor ing requirements/operatin g limits (secondary voltage and current ) where opacity is already monitored;

 Setting operating limits as enforceable excess emissions points instead of corrective action triggers; and

 Reduction in monitoring allowances.

W e have conducted a review of t he data used in developing the proposed opacity limit. Table 3 A above summarizes the COMS data reviewed for recovery furnaces. Most of the recovery furnaces in the U.S. were included in this analysis. Of the COMS data sets analyzed, 141 of 160

total data sets achieved the 20 percent opacity limit with a 2 percent monitoring allowance proposed for subpart BBa. In response to comments on the proposal, EPA broke the recovery furnace COMS data into new, modified, and existing sources based on the reason each recov ery furnace became subject to the NSPS following the 1976 applicability date ( e.g. , new units installed after 1976, modifications occurring after 1976). While a few recovery furnaces that became subject to the NSPS when they were installed or modified did not achieve the limit prosed for subpart BBa, we note that these units all became subject to the NSPS over 20 years ago. Recovery furnaces that have come online as new units or been upgraded over the past decade showed compliance with the proposed 20 perce nt opacity limit with a 2 percent monitoring allowance. The EPA is unaware of any technological reason that would hinder modified units from meeting this limit, especially considering that the majority of existing sources not subject to the NSPS already me et the proposed limit.

Based on our analysis of the COMS data showing that 20 percent opacity (with a 2 percent monitoring allowance calculated on a semiannual basis) has been achieved by most of the recovery furnaces in the U.S., and given the opacity le vels established under subpart MM and permit limits, we maintain that 20 percent opacity (with a 2 percent monitoring allowance calculated on a semiannual basis) has been adequately demonstrated and we are finalizing this limit in subpart BBa.

Regarding th e commenter’s concern that sources using COMS should not also be required to conduct ESP parameter monitoring, we proposed ESP parameter monitoring in addition to

COMS use so affected units would have a mechanism to show continuous compliance with the

PM c oncentration standards at all times, including periods when the opacity monitoring

allowance is used. As discussed in section 4.1 of this document, the EPA has included language in subpart BBa to clarify that the standards apply at all times as specified i n the monitoring and testing provisions in the rule . The ESP monitoring requirements were added to provide a measure of continuous compliance in order to enable retention of an opacity monitoring

allowance in the NSPS . The 2 percent opacity monitoring allowance will only be available for recovery furnaces with ESP parameters that are above the minimum limits established during the125

PM performance test ( i.e. , above the minimum secondary current and secondary voltage or above

min imum total secondary power).

Regarding the commenter’s concern about the reduction in excess emissions monitoring

allowances for opacity from 6 percent of the moni toring periods while excluding periods of S/S

, to 2 percent of the monitoring periods while including p eriods of S/S

, t he proposed rule specified

these allowances based on our review of the COMS data. In light of comments questioning certain aspects of our analysis, we have reanalyzed the COMS data following proposal (as described in Section 3). The reanalysis supports the original conclusions in the proposal regarding the ability of sources to meet the proposed standard during both normal operations and periods of S/S. The most significant change we are making as a result of our reanalysis of the COMS data is to require calculation of the opacity monitoring allowance on a semiannual basis instead of quarterly.

We acknowledge that simultaneous implementation of NSPS, NESHAP, and s tate rules is complex and that there could be some inconsistencie s especially while EPA is in the process of updating Federal rules to address SSM. While the revised NSPS subpart BBa may seem more complicated than subpart BB, we note that EPA has added language to the revised NSPS to update the NSPS requirements to be c onsistent with the NES H AP and clarify how emissions are to be reported during time periods that previously were not required to be addressed ( e.g. , S/S periods). Several of the new requirements added to the revised NSPS were included to ensure adequate fle xibility was maintained in the NSPS in light of the need to address SSM periods. Review of the NESHAP (subpart MM) is forthcoming and will provide an opportunity for EPA to address SSM in a manner consistent with the revised NSPS. While EPA hopes that s tat e rules will be consistent with Federal rules, we note that s tate rules

, and the timing in which s tate requirements are made consistent with Federal rules as they are updated

, may vary
, and this timing is not entirely within EPA’s control

. Finally, as the commenter mentioned, this is a technology

- based review, so health risks cannot be a consideration for this rule. No health risk

assessment has been conducted for this rule.126 

## 6

. Cost and Impacts

6

- 01 Comment : Commenter 0059 submitted comments on the costs associated with the proposed NSPS review, specifically the costs associated with lowering the NSPS PM emission

limits for modified and reconstructed SDTs and for modified lime kilns. These comments were previ ously submitted to EPA prior to proposal and can be found in the document titled

, Meeting Notes for the March 14, 2013 meeting with AF&PA and NCASI

, in the docket for the proposed rulemaking.

Response: We received and evaluated the aforementioned comments prior to proposal of the NSPS review and took them into account in preparing the costs of the proposal, which can be

found in the memorandum titled

, Emissions Inventory for Kraft Pulp Mills and Costs/Impacts of the Section 111(b) Review of the Kraft Pulp M ills NSPS

, in the docket for the proposed rulemaking. We appreciate the commenter’s input to the cost estimates for the proposed rule.

6

- 02 Comment : Commenter 0056 supported EPA’s decision and rationale for maintaining the modified recovery furnace PM limit. The commenter noted that, because modified unit status under the NSPS has no equivalent status trigger under the NESHAP regulations, EPA evaluated the cost effectiveness of moving the PM limit for such modified units to the more restrictive PM

limits under the s ubpart MM NESHAP for new and reconstructed units. The commenter further noted that EPA found “poor cost effectiveness” as a result, especial ly for modified units

, that for economic reasons would need to attempt to comply with more stringent limits by upgrading existing controls, and that EPA chose to retain the current NSPS limit. 198 The commenter agreed that this was an appropriate choice.

Resp onse: We appreciate the commenter’s support for our decision to maintain the current PM emission limit for modified kraft recovery furnaces.

198 See 78 FR 31323.127 

## 7

. Greenhouse Gas Emissions

7

- 01 Comment: Commenters 0057 and 0059 presented opposing arguments regarding the

re gulation of GHGs from kraft pulp mills. Commenter 0059 argued that EPA has ample practical reasons not to consider adding GHGs to the kraft pulp mill NSPS

. The commenter stated that EPA is not required to promulgate NSPS for all, or indeed for any, pollutants emitted by a particular source category. Although EPA has made an “endangerment finding” with respect to GHG emissions from motor vehicles, 199 the commenter contended that this finding does not by its terms address GHG emissions from pulp mills. B ut even if it did, the commenter argued that

section 111 contains no requirement that EPA include emission limitations in current NSPS for all air pollutants that are emitted by a given source category, even for pollutants that EPA has determined may reaso nably be anticipated to en danger public health or welfare, 200 in contrast to section 202(a)(1), which requires EPA to set standards for emissions of “any air pollutant” from new motor vehicles that, in the Administrator’s judgment, cause or contribute to air pollution that “may reasonably be anticipated to en danger public health or welfare. ”

C ommenter 0059 contended that

, i n any event, including GHGs in the kraft pulp mill NSPS would be premature. First, the commenter noted that no court has held that EPA is authorized to

use NSPS under CAA section 111 to combat climate change. 201 According to the commenter,

the re are numerous reasons why CAA section 111 is not an appropriate vehicle for addressing climate change. Among other things, the commenter cited the f act that GHG emissions do not have local effects, but have been identified as a concern only as they build up in the global atmosphere, which, according to the commenter, means that controlling their emissions from new and modified sources using the best d emonstrated technology is likely not to be the most

cost

- efficient way of achieving desired reductions in global GHG emissions. The commenter

stated that v irtually everyone agrees that stabilizing GHG concentrations in the global atmosphere would be an eno rmously costly proposition, and

, therefore

, it is particularly important that any GHG reductions be obtained in a cost

- effective manner. The commenter pointed out that NSPS, which by statute must be based on an evaluation of the best

- performing

emission co ntrol technology for a particular emission unit, do not incorporate any explicit consideration of whether the same or greater reduction in GHGs could be achieved at lower cost through other measures. The commenter also pointed out that NSPS typically are e xpressed as uniform emission rates for every unit in a particular source category or subcategory, without providing for consideration of site

- specific factors or incorporating the flexibility necessary to

minimize the cost of emission reductions on a globa l scale.

Commenter 0059 contended that i nclu ding GHGs in the kraft pulp mill NSPS would be premature on technical grounds, as well. According to the commenter, t echnologies for control of GHGs are just beginning to be developed, and it could actually be c ounterproductive for EPA

199 74 FR 66496 (Dec. 15, 2009).

200 Compare CAA sections 111(b)(1)(A), (f)(2)(B), and (g)(2).

201 See, e.g. , EPA’s Combined Motion To Govern Further Proceedings and Response to Environmental and State

Petit ioners’ Motion To Govern Further Proceedings in New York v. EPA , D.C. Cir. No. 06

- 1322, June 18, 2007, at 8 (“To date neither Massachusetts nor any other judicial decision has specifically addressed either the legal or policy aspects of the potential regulation of greenhouse gas emissions under section 111 of the Act....”).128

to establish NSPS for GHGs, which likely would not be reviewed for at least another 8 years, based on current technologies. The commenter also noted that a large portion of GHG emissions from kraft pulp mills comes from biomass, and pointed out that EPA is currently in the midst of developing its policy with respect to regulation of biogenic GHG emissions, in light of the carbon cycle. 202 As an example, the commenter indicated that a recovery furnace can be viewe d

as an energy efficiency device

— recovering energy value from a byproduct of the pulping process that would otherwise be wasted

— and also a device whose carbon emissions displace

carbon emissions from fossil fuel that otherwise would be transformed from sub surface deposit to atmospheric pollutant. The commenter stated that EPA does not yet have the conceptual framework to address these distinct qualities of pulp mill GHG emission sources. Thus, according to the commenter, there are numerous legal and practic al reasons for EPA to exercise its ample discretion not to include GHGs in the kraft pulp mill NSPS

.

By contrast, c ommenter 0057 argued that GHG emissions, especially CO 2 , should be inventoried, monitored

, and analyzed for future review of the NSPS for kr aft pulp mills. According to the commenter, e stimates for the pulp and paper industry as a whole indicate that

CO 2 emissions from biogenic sources, such as black liquor and other waste biomass at pulp mills, are approximately double the emissions from other fuel combustion. 203 The commenter noted, however, that the se substantial biogenic CO 2 emissions are not currently reported for the purpose

of GHG inventories. Consequently, the commenter indicated there are no accurate m easures of

the total GHG emissions from pulp mills. Commenter 0057 contended that t hese biogenic

emissions should be inventoried just as fossil sources are currently inventoried for GHG emissions. Even though these CO 2 emissions are biogenic i n origin, the commenter stated that

EPA must consider how they could be reduced through improvements in efficiency or other

methods.

Response: We agree with commenter 0059 that GHG emissions, regardless of biogenic or non

biogenic origin, we re outside the scope of the proposed NSPS review. The proposed NSPS

review focused on the PM and TRS emission standards in subpart BB that were due for review under CAA section 111(b)(1)(B).

Even though GHG emissions were outside of the scope of the propos ed NSPS review,

commenter 0057 raises other topics that we would like to address here. First, we disagree with

commenter 0057 that CO 2 emissions from the combustion of black liquor and biomass are not reported for the purpose of GHG inventories and that th ere are no accurate measures of the total

GHG emissions from pulp mills. The pulp and paper industry reports biogenic CO 2 emissions from black liquor and biomass combustion through EPA’s GHGRP, and has done so since 2010. Under the GHGRP, biogenic CO 2 emis sions are reported separately from the C O 2 e emissions associated with (a) CO 2 from burning fossil fuels, (b) CH 4 and N 2 O from burning biomass and fossil fuels, and (c) process

- related CO 2 ( e.g. , from sorbent or make

- up chemical use). Based on reporting yea r 2012 data from the GHGRP, commenter 0057 is correct that biogenic CO 2 emissions from the pulp and paper industry are higher than emissions of non

- biogenic CO 2 e (42 million metric tons).

202 See 76 FR 43 490 (July 20, 2011).

203 U.S. Environmental Protection Agency. Available and Emerging Technologies for Reducing Greenhouse Gas Emissions from the Pulp and Paper Industry

. 2010.129

Given the scientific and technical issues surrounding biogenic CO 2 ( e.g. , carbon cycle considerations), since 2010 and while EPA has been collecting biogenic CO 2 emissions data

f r o m the pulp and paper industry under the GHGRP, EPA has also taken a number of actions related to biogenic CO 2 emissions from stationary sources . These EPA actions include issuing a call for information on GHG emissions associated with bioenergy and other biogenic s ources and drafting an Accounting Framework for Biogenic C O 2 Emissions from Stationary Sources for p eer review by a SAB panel specially convened to study the scientific and technical issues associated with biogenic CO 2

. The final peer review report from the SAB panel on the draft framework was published on September 28, 2012. The EPA is currently in the process of determining the appropriate next steps with respect to biogenic CO 2

.

We also note that the EPA is taking common

- sense steps to regulating GHG emissions from stationary sources, beginning with the largest sources of GHG ( i.e. , power plants). According to data from the GHGRP, GHG emissions from the pulp and paper industry are only a small fraction of the approximately 2 billion metric tons of GHG emissions from the power sector, even considering biogenic CO 2 emissions.