United States Environmental Protection Agency



# Summary of Public Comments and Responses for the

National Emissions Standards for Hazardous Air Pollutants: Mineral Wool Production and Wool Fiberglass Manufacturing (Risk and Technology Review)

June 2015This page intentionally left blankNATIONAL EMISSIONS STANDARDS FOR HAZARDOUS AIR POLLUTANTS: MINERAL WOOL PRODUCTION AND WOOL FIBERGLASS MANUFACTURING (RISK AND TECHNOLOGY REVIEW)

SUMMARY OF PUBLIC COMMENTS AND RESPONSES

U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policies and Programs Division Research Tri angle Park, North Carolina 27711

June 2 5 , 2015

The primary contact regarding questions or comments on this document is:

Susan Fairchild U.S. Environmental Protection Agency Metals and Minerals Group (D243

- 02) Research Triangle Park, North Carolina 27711

Email : Fairchild. Susan@epa .govSummary of Public Response to Commen ts N

ESHAP: Mineral Wool Production And Wool Fiberglass Manufacturing (Risk And Technology Review)

TABLE OF CONTENTS

Section Page

I. INTRODUCTION

................................ ................................ ................................ ............. 1

II. LIST OF COMMENTERS

- MINERAL WOOL

................................ .......................... 3

III. LIST OF COMMENTERS

- WOOL FIBERGLASS

................................ .................... 5

IV. GENERAL COMMENTS PER TAINING TO BOTH MINE RAL WOOL PRODUCTION AND WOOL FIBER GLASS MANUFACTURING

.......................... 7
A. Risk Assessment

................................ ................................ ................................ ............ 7
B. Ample Margin of Safety Analysis

................................ ................................ ............... 30
C. UPL Approach to Limited Datasets

................................ ................................ ............. 46
D. SSM Provisions

................................ ................................ ................................ ............ 54
E. Authority to Fill Data Gaps in Existing MACT Standards

................................ .......... 72
F. M onitoring, Recordkeeping and Reporting

................................ ................................ . 73
G. G eneral A pproach T o C alculating MACT

................................ ................................ ... 76

V. MINERAL WOOL PRODUCT ION (SUBPART DDD)

................................ ............. 88
A. Cupola PM Limits

................................ ................................ ................................ ........ 88
B. Cupola HF and HCl Limits

................................ ................................ .......................... 88
C. Cupola COS Limit

................................ ................................ ................................ ..... 105
D. Colle ction and Curing limits

................................ ................................ ...................... 111
E. Compliance Schedule

................................ ................................ ................................ . 114
F. Small Business and Economic Impacts

................................ ................................ ..... 114
G. Environmental Benefits

................................ ................................ ............................. 119
H. Surrogacy

................................ ................................ ................................ ................... 120
I. Testing and monitoring Issues

................................ ................................ ................... 121
J. Miscellaneous

................................ ................................ ................................ ............ 121

VI. WOOL FIBERGLASS MANU FACTURING SOURCE CAT EGORY

.................. 123
A. Issues Related to Both Major and Area Sources

................................ ........................ 123 1. Chromium Emission Limits for Gas

- Fired Glass

- Melting Furnaces

.................. 123 2. PM Limit for Glass

- Melting Furnaces

................................ ................................ 131 3. Testing and Monitoring Issues

................................ ................................ ............ 137
B. Issues Related to Major Sources Only

................................ ................................ ....... 140 1. Applicability

................................ ................................ ................................ ....... 140 2. Technol ogy Developments and Controls

................................ ............................ 141 3. HCl and HF Emission Limits for Glass

- Melting Furnaces

................................ . 141 4. Formaldehyde, Phenol, and Methanol Limits

................................ ..................... 150 5. Compliance Schedule

................................ ................................ .......................... 156

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ESHAP: Mineral Wool Production And Wool Fiberglass Manufacturing (Risk And Technology Review)

TABLE OF CONTENTS (Continued)

Section Page

6. Economic Impacts

................................ ................................ ............................... 162 7. MACT Floor Analyses

................................ ................................ ........................ 166 8. Environmental Justice

................................ ................................ ......................... 170 9. Miscellaneous

................................ ................................ ................................ ..... 186
C. Issues Related to Area Sources Only

................................ ................................ ......... 189 1. EPA Decision and Authority to Regulate Area Sources

................................ ..... 189 2. Decision to Apply GACT to Area Sources

................................ ......................... 190 3. Glass

- Melting Furnace Emission Limits

................................ ............................ 191 4. Economic Impacts

................................ ................................ ............................... 192 5. Miscellaneous

................................ ................................ ................................ ..... 194

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LIST OF ACRONYMS AND ABBREVIATIONS

ATSDR Agency for Toxic Substances and Disease Registry AEGL Acute Exposure Guideline Level
BDL Below Detection Limit (of the method) BLDS Bag Leak Detection System CAA Clean Air Act CA

- REL California Reference Exposure Level CEMS Continuous Emissions Monitoring System CERCLA Comprehensive Environmental Respo nse, Compensation, and Liability Act of 1980 CL Confidence Limit
CIIT Chemical Industry Institute of Toxicology CSEFH Child

- Specific Exposure Factors Handbook CTE Central Tendency Exposure CWA Clean Water Act D/F Dioxins and Furans dscm Dry standard cubic meters
EFH Exposure Factors Handbook
EPA U. S. Environmental Protection Agency EPCRA Emergency Planning and Community Right

- to

- Know Act ERPG Emergency Response Planning Guideline
FR Federal Register GACT Generally Available Control Technology GEAE Generic Ecological Assessment Endpoint
HAP Hazardous Air Pollutant
HEM Human Exposure Model
HEPA High Efficiency Particulate Air Filter
HI Hazard Index HON Hazardous Organic NESHAP HQ Hazard Quotient IQ Intelligence quotient IQA Information Quality Act IRIS Integrated Risk Information System LOAEL Lowest Observable Adverse Effect Level MACT Maximum Achievable Control Technology
MDL Minimum Detection Limit (of the pollutant)
MEI Maximum Exposed Individual
MIR Maximum Individual Risk NAAQS National Ambient Air Quality Standards
NEI National Emissions Inventory NESHAP National Emission Standards for Hazardous Air Pollutants

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NOAEL No Observable Adverse Effect Level OAQPS Office of Air Quality Planning and Standards ODW Office of Drinking Water OEHHA Office of Environmental Health Hazard Assessment OHEA Office of Health and Environmental Assessment
PB

- HAP Persistent Bioaccumulative Hazardous Air Pollutant

ppmv Parts per million by volume
PEL Probable Effect Level PSD Prevention of Significant Deterioration RCRA Resource Conservation and Recovery Act
RDL Representative Detection Limit (of the pollutant)
REL Reference Exposure Level RfC Reference Concentrations
RME Reasonable Maximum Exposure RQ Reportable Quantity (CERCLA)
RTR Risk and Technology Review SAB Science Advisory Board SARA Superfund Amendments and Reauthorization Act SIC Standard Industrial Classification SIP State Implementation Plan SOP Standard Operating Procedure SSM Startup, Shutdown, and Malfunction STEL Short

- term Exposure Limit
TEF Toxic Equivalency Factor TOSHI Target Organ specific Hazard Index
TRI Toxic Release Inventory
UPL Upper Predictive Limit
URE Unit Risk Exposure WHO World Health Organization

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I. INTRODUCTION On June 1, 1999 (64 FR 29490), the EPA promulgated the National Emission Standards for Hazardous Air Pollutants (NESHAP) for the Mineral Wool Production source category (40 CFR part 63, subpart DDD). The EPA promulgated the NESHAP for the Wool Fiberglass Manufacturing source category (40 C FR part 63, subpart NNN) on June 14, 1999 (62 FR 31695). Under section 112(d)(6) of the Clean Air Act ( CAA ), t he EPA is required to review NESHAP no less frequently than every 8 years following promulgation and to revise the standards ‘‘as necessary, takin g into account developments in practices, processes, and control technologies.’’ Additionally, under section 112(f)(2), the EPA must evaluate the risk to public health remaining after application of the technology

- based standards and revise the standards, if necessary to provide an ample margin of safety to protect public health or to prevent, taking into consideration costs, energy, safety and other relevant factors, an adverse environmental effect. The residual risk review is also required within 8 years after promulgation of the technology

based standards. This review process is referred to as the Residual Risk and Technology Review (RTR).

On November 25, 2011 (76 FR 72770), EPA proposed revisions to the Mineral Wool Production and the Wool Fiberglass Man ufacturing NESHAP to address the results of the RTR. In the November 2011 notice, the EPA proposed several amendments to both NESHAP and announced the a gency’s intention to list and to regulate area sources in the wool fiberglass area source category pendi ng the collection of new test data. Following the November 2011 proposal, the EPA obtained information regarding PM and chromium compounds that are either used in or emitted by glass

- melting furnaces in the wool fiberglass manufacturing industry through an information collection request (ICR) under CAA section 114. The EPA published a supplemental proposal on April 15, 2013 (78 FR 22369) that made corrections to the November 2011 proposal for the Mineral Wool Production and Wool Fiberglass Manufacturing sou rce categories, addressed certain comments received on the earlier November 25, 2011 proposal, added gas

fired glass

- melting furnaces at area sources in the Wool Fiberglass Manufacturing source category to the category list, under CAA sections 112(c)(3) an d 112(k)(3)(B), and proposed first

time standards for these sources under CAA section 112(d)(5).

On November 13, 2014 (79 FR 68012), the EPA proposed, and requested comment on, revisions and clarifications to the following aspects addressed under previous proposals:

• Additional explanation of the upper prediction limit (UPL) approach;

• An explanation of our approach to limited datasets;

• An explanation of why we are withdrawing the proposed provisions establishing an affirmative defense to civil penalties fo r violations caused by malfunctions;

• Proposed basis for our determination on ecological effects of pollutants emitted from major sources in these source categories;

• Work practice requirements at startup and shutdown for mineral wool production and wool fiberglass manufacturing source categories under CAA section 112(h)(2);

• Changes to previously proposed emission limits for the mineral wool production source category;

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• Changes to previously proposed standards for both major and area sources in the wool fib erglass manufacturing source category.

This document contains summaries of the public comments that the EPA recei ved on the proposed standards. The preamble to the final rules also contains responses to significant public comments. Copies of all comments submitted are available at the EPA docket Center Public Reading Room. Comment letters and transcripts of the public hearings are also available

e lectronically through http://www.regulations.gov by searching Docket IDs EPA

- HQ

- OAR

2010

- 1041 and

- 1042.

This document does not contain comment summaries or responses to comments submitted in response to the follo wing proposed regulatory changes because the EPA has already provided responses to these comments in the preamble to the 2013 proposal (78 FR 22370, April 15, 2013) and the preamble to the 2014 proposal (79 FR 68011, November 13, 2014) and is not finalizin g these changes :

• Establishing an affirmative defense to civil penalties for violations caused by malfunctions, including revised compliance date for provisions related to affirmative defense and definition of affirmative defense (see 79 FR 68015 for expla nation).

• Establishing numerical emission limits for startup and shutdown periods (see 78 FR 22378

- 22379 and 22388 for explanation).

• Establishing numerical emission limits for hydrogen chloride ( HCl ) and hydrogen fluoride ( HF ) from for wool fiberglass fur naces (78 FR 22387 for explanation).

• Requiring use of EPA Method 202 when measuring particulate matter from wool fiberglass furnaces (78 FR 22386 for explanation).

• Using a sodium hydroxide (NaOH) scrubber as the EPA’s technology basis for reducing chromium emissions from wool fiberglass furnaces (79 FR 68020

- 69024 for explanation).

• Requiring use of Method 26A or Method 320 to test HF and HCl.

In this document, we are including comment summaries of comments related to the formaldehyde, methanol, and phenol emissions from wool fiberglass manufacturing lines that use rotary spin (RS) lines . However
, t he EPA is not finalizing in this final rulemaking a revised emission limit for formaldehyde for RS lines or new emission limits for methanol and phenol for RS lin es. The EPA will address these limits in a future rulemaking. Based on the information available to the EPA, the majority of wool fiberglass facilities no longer use phenol/formaldehyde ( PF ) binder and only one facility currently manufactures product using a PF binder. W e have issued a CAA Section 114 ICR to obtain emissions and process data from RS production lines. See section V.H of the preamble to the final rule for a more complete discussion of EPA’s decision regarding PF binder production lines.

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II. LIS T OF COMMENTERS

- MINERAL WOOL

Table 2

- 1 presents the public comment letters received by the EPA in resp onse to the 2011, 2013, and 2014 proposals for the mineral wool production source category. The table shows the commenter, affiliation, and identificati on number assigned to each letter in Docket EPA

- HQ

- OAR

- 2010

- 1041.

Table 2

- 1. Public Comments for Mineral Wool Production NESHAP, Proposed Rules Docket EPA EPA

- HQ

- OAR

- 2010

- 1041

Commenter ID Commenter Affiliation
November 25, 2011 Proposal

1041

- 0073 Russell S. Frye SSM Coalition (duplicate of 1042

- 0111)

1041

- 0074 Vinson Hellwig and Robert Colby National Association of Clean Air Agencies (NACAA) (duplicate of 1042

- 0113)

1041

- 0075 James and Dorothy McField Private Citizens (duplicate of 1042

- 0117)

1041

- 0076 E. Tellis Private Citizen

1041

- 0077 Melvin Keener Coalition for Responsible Waste Incineration (duplicate of 1042

- 0116)

1041

- 0078 Ann Mason American Chemistry Council (ACC) (duplicate of 1042

- 0119)

1041

- 0079 Mathew Todd Residual Risk Coalition (R2C)

1041

- 0080 Angus Crane and Christopher Martin North American Insulation Manufacturers Association (NAIMA)

1041

- 0 0 81

Emma Cheuse E arthjustice on behalf of Sierra Club and Oak Grove Neighborhood Association, Inc. 1041

- 0 0 82
1041

- 0 083
1041

- 0 0 84
1041

- 0 0 85

1041

- 0 0 86
1041

- 0 0 87 April 15, 2013 Supplemental Proposal

1041

- 0123 David T. Hudson Strategic Materials, Inc.

1041

- 0124 G. Vinson Hellwig and Robert H. Colby NACAA (duplicate of 1042

- 0298 )

1041

- 0125 Emma Cheuse Earthjustice on behalf of Sierra Club and Oak Grove Neighborhood Association (duplicate of 1042

- 0299 )

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Table 2

- 1. Public Comments for Mineral Wool Production NESHAP, Proposed Rules Docket EPA EPA

- HQ

- OAR

- 2010

- 1041

Commenter ID Commenter Affiliation

1041

- 0126 Angus E. Crane NAIMA (restatement of comments from 1041

- 0080)

1041

- 0127 Angus E. Crane NAIMA
November 13, 2014 Supplemental Proposal

1041

- 0162 Ken Cammarato Roxul USA, Inc.

1041

- 0163 Ken Cammarato Roxul USA, Inc.

1041

- 0164 Angus E. Crane NAIMA

1041

- 0165 Emma Cheuse Earthjustice on behalf of Sierra Club

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III. LIST OF COMMENTERS

- WOOL FIBERGLASS

Table 3

- 1 presents the public comment letters received by the EPA received in response to the 2011, 2013, and 2015 proposals for the wool fiberglass manufacturing source category. The table presents the commenter, affiliation, and identification number ass igned to each letter in Docket EPA

- HQ

- OAR

- 2010

- 1042.

Table 3

- 1. Public Comments for Wool Fiberglass Manufacturing NESHAP, Proposed Rules Docket EPA EPA

- HQ

- OAR

- 2010

- 1042
Commenter ID Commenter Affiliation November 25, 2011 Proposal
1042

- 0108 Anonymous Private Citizen

1042

- 0111 Russell S. Frye SSM Coalition (duplicate of 1041

- 0073)

1042

- 0112 Marvin Robinson, II Quindaro Ruins/ UGRR Exercise 2012

1042

- 0113 Vinson Hellwig and Robert Colby NACAA (duplicate of 1041

- 074)

1042

- 0115a Richard Mabion Kansas Sierra Club

1042

- 0115b Rachel Jefferson Southeast Blvd & Quindaro Blvd. Family Health Care
1042

- 0115c Junette Hunter Private Citizen
1042

- 0115d Chester Owens Private Citizen
1042

- 0115e Marilyn White Private Citizen
1042

- 0115f Craig Volland Private Citizen
1042

- 0115g L.V. Quinn Private Citizen
1042

- 0115h Marvin Robinson, II Quindaro Ruins / UGRR Exercise 2012
1042

- 0115i Clintel Betts Private Citizen
1042

- 0115j Angus Crane NAIMA
1042

- 0115k Elnora Jefferson Oak Grove Neighborhood Association

1042

- 0116 Melvin Keener Coalition for Responsible Waste Incineration (duplicate of 1041

- 0077)

1042

- 0117 James and Dorothy McField Private Citizens (duplicate of 1041

- 0075)

1042

- 0118 Mathew Todd R2C (duplicate of 1041

- 0079)

1042

- 0119 Ann Mason ACC (duplicate of 1041

- 0078)

1042

- 0120 Angus Crane and Christopher Martin NAIMA

1042

- 0121

Emma Cheuse Earthjustice on behalf of Sierra Club and Oak Grove Neighborhood Association, Inc. (duplicate of 1041

- 0080) 1042

- 0122

1042

- 0123

1042

- 0124

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Table 3

- 1. Public Comments for Wool Fiberglass Manufacturing NESHAP, Proposed Rules Docket EPA EPA

- HQ

- OAR

- 2010

- 1042
Commenter ID Commenter Affiliation
1042

- 0125

1042

- 0126 Lauren Alterman Saint

- Gobain Corporation

1042

- 0127 Angus Crane and Christopher Martin NAIMA

April 15, 2013 Supplemental Proposal

1042

- 0298 G. Vinson Hellwig and Robert H. Colby NACAA (duplicate of 1041

- 0124)

1042

- 0299 Emma Cheuse Earthjustice on behalf of Sierra Club and Oak Grove Neighborhood Association (duplicate of 1041

- 0125)

1042

- 0300 Angus E. Crane NAIMA November 13, 2014 Supplemental Proposal 1042

- 0348 Angus E. Crane and Christopher C. Martin NAIMA

1042

- 0347 Emma Cheuse Earthjustice on behalf of Sierra Club

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IV. GENERAL COMMENTS PER TAINING TO BOTH MINE RAL WOOL PRODUCTION AND WOOL FIBERGLASS MANUFACTU RING

A. Risk Assessment

1. Comment: One commenter (1041

- 0074/1042

- 0113) stated that Acute Exposure Guideline Levels (AEGLs) and Emergency Response Planning Guidelines (ERPGs) were developed for accidental release emergency planning and they are not appropriate for assessing daily human exposure to toxic air pollutants because they do not includ e adequate safety and uncertainty factors. The commenter stated that they are not meant to evaluate the acute impacts from routine emissions that occur over the life of a facility and cannot be relied upon to protect the public from the adverse effects of exposure to toxic air pollutants. The commenter concluded that their use is not appropriate in risk assessments and urged the EPA to increase its reliance on the California Reference Exposure Levels (RELs) to address acute exposures in the residual risk

as sessments.

Response: The acute assessment is not an assessment of daily human exposure. Rather, the acute assessment uses conservative estimates of maximum hourly emissions to assess potential impacts of short

- term, acute exposures. As such, AEGLs and ERPG values are among the appropriate values to use in the acute assessment. The EPA does not rely exclusively upon AEGL or ERPG values for assessment of acute exposures. Rather, the EPA’s approach is to consider various acute health effect reference values, i ncluding the California REL, in assessing the potential for risks from acute exposures. To better characterize the potential health risks associated with estimated acute exposures to HAP, and in response to a key recommendation from the SAB’s peer review o f the EPA’s RTR risk assessment methodologies, 1 we generally examine a wider range of available acute health metrics ( e.g., RELs, AEGLs) than we do for our chronic risk assessments. This is in response to the SAB’s acknowledgement that there are generally more data gaps and inconsistencies in acute reference values than there are in chronic reference values. In some cases, when Reference Value Arrays 2 for HAP have been developed, we consider additional acute values (i.e., occupational and international valu es) to provide a more complete risk characterization. T he exposure guidelines EPA considers depends on which exposure guidelines are available for the various hazardous air pollutants emitted. The EPA uses AEGL and ERPG values (when available) in conjuncti on with REL values (again, when available) to characterize potential acute health risks. However, it is often the case that HAP do not have all of these acute reference benchmark values. In these instances, the EPA describes the potential acute health risk in relation to the acute health values that are available. Importantly, when interpreting the results, we are careful to identify the benchmark being used and the health implications associated with any specific benchmark being exceeded.

1 The SAB peer review of RTR Risk Assessment Methodologies is available at: http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File/EPA

- SAB

- 10

- 007

- unsigned.pdf

. 2 U.S. EPA. (2009) Ch apter 2.9 Chemical Specific Reference Values for Formaldehyde in Graphical Arrays of Chemical

- Specific Health Effect Reference Values for Inhalation Exposures (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R

– 09/061, and avail able on

- line at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=211003

.

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2. Comment : Two com menters (1042

- 0121 and 1041

- 0074/1042

- 0113) objected to the EPA’s use of the geographic centroid of the census block in the risk assessment instead of the closest or maximum point of exposure. One commenter explained that this approach underestimates expos ure and could easily be remedied because HEM

- AERMOD allows the system to make such an adjustment. The commenter noted that this conflicts with the recommendation of the SAB, which has urged the EPA to consider “specific locations of residences.” That comme nter added that the EPA has regularly received comments on this issue from state air pollution control agencies in past rulemakings. That commenter recommended that in this and future rulemakings, the EPA should follow the advice of these state regulators and start assessing risk at the edge or fence

- line of the facility

– i.e. , the point of maximum exposure

– not just at the centroid of a census block. That commenter concluded that failing to do so would be unlawful, arbitrary and capricious, as this appro ach fails to assess risk for the person “most exposed” to the source category‘s emissions.

The commenters stated that census blocks are not homogeneous and, even if the area near the property line is not developed, over time homes and businesses could loc ate closer to the facility. The commenters also believed the EPA has at other times recognized that the maximum exposed individual for acute risks is likely present closer to or at the fence line.

Another commenter (1042

- 0115f) stated that some neighborin g residents live on the bluffs overlooking the Fairfax industrial district (Kansas City, K ansas ) at an elevation above the tops of some of the smoke stacks. While the EPA's model does take nearby terrain into account, the commenter was concerned that it ma kes the exposure calculation only at the center of the census tract. The commenter noted that this would underestimate the risk to residents living on the edge of the track toward the stacks. That commenter argued that the modeling would not adequately con sider the risk to anyone working regularly just beyond the fence line of the CertainTeed plant. According to that commenter, the model does not fully take into account the lifetime of harm that can be caused when a child is exposed at an early age to toxic chemicals.

Response: In a national

- scale assessment of lifetime inhalation exposures and health risks from facilities in a source category, it is appropriate to identify exposure locations where it may be reasonably expected that an individual will spend a majority of his or her lifetime. In determining chronic risks, it is appropriate to use census block information on where people actually reside, rather than points at the property line, to locate the estimation of exposures and risks to individuals livi ng near such facilities. Census blocks are the finest resolution available as part of the nationwide population data (as developed by the U.S. Census Bureau); on average, a census block is comprised of approximately 40 people and about 10 households. In th e EPA risk assessments, the geographic centroid of each census block containing at least one person is used to represent the location where all the people in that census block live. The census block centroid with the highest estimated exposure then becomes the location of maximum exposure, and the entire population of that census block is assumed to experience the maximum individual risk. In some cases, because actual residence locations may be closer or farther from facility emission points, this may resul t in an overestimate or underestimate of the actual annual concentrations (although there is no systematic bias for average levels). Given the relatively small dimensions of census block in densely

- populated areas, there is little uncertainty introduced by using the census block centroids in lieu of actual residence locations. There is the potential for more uncertainty when the census block are larger, although there is still no systematic bias. The EPA

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concludes that the most appropriate locations at whic h to estimate chronic exposures and risks are the census block centroids because: ( 1) census blocks are the finest resolution available in the national census data; ( 2) facility fence lines do not typically represent locations where chronic exposures are l ikely (i.e., people do not typically live at the fence line of facilities); and ( 3) there is no bias introduced into the estimate of the maximum individual risk (MIR) by using census block centroid locations. In its peer review of the methodologies used to estimate risks as part of the RTR rulemaking efforts, the EPA’s Science Advisory Board (SAB) endorsed this approach. 3

3. Comment: One c ommenter (1041

- 0081) stated that in assessing acute health risk, the EPA used a multiplier of 10 to assess the peak 1

- hour emissions, compared to average emission rates, for Wool Fiberglass, and a factor of 3 for Mineral Wool. As a result, the commenter noted that the EPA found that the highest, worst

- case acute hazard quotient ( HQ ) for the Wool Fiberglass source category is 3 0, based on the acute REL for formaldehyde, and for Mineral Wool it is 8, based on formaldehyde. According to the commenter, the EPA has not demonstrated that using a factor of 10 is high enough for Wool Fiberglass to assess the true acute risk to the most

- exposed individual and community under the EPA’s existing standards and that its use is therefore not justified.

Response: The acute risk assessment methodology uses a tiered, iterative approach that begins with an assessment of an approximation of a worst

- case exposure. To this end, we assumed that peak 1

- hour emissions are equal to 10 times the average 1

- hour emissions rate for the wool fiberglass manufacturing source category and 3 times the average 1

- hour emissions rate for the mineral wool manufacturing source category, which are only one of the worst

- case assumptions that we made for each source category in our acute hea lth risk screening analysis. Other worst

- case assumptions included:

• For facilities with multiple emission points, peak 1

- hour emissions were assumed to occur at all emission points at the same time.

• For facilities with multiple emission points, 1

- hour con centrations at each receptor were assumed to be the sum of the maximum concentrations due to each emission point, regardless of whether those maximum concentrations occurred during the same hour.

• Worst

- case meteorology (from one year of local meteorology) was assumed to occur at the same time the peak emission rates occur. The recommended EPA local

- scale dispersion model, AERMOD, is used for simulating atmospheric dispersion.

• A person was assumed to be located downwind at the point of maximum impact during this same 1

- hour period, but no nearer to the source than 100 meters.

3 U.S. Environmental Protection Agency, Office of the Administrator Science Advisory Board. Review of EPA’s draft entitled, “Risk and Technology Review (RTR) Risk Assessment Methodologies: For Review by the EPA’s Science Advisory Board with Case Studies

– MACT I Petroleum Refining Sources and Portland Cement Manufacturing.” EPA

- SAB

- 10

- 007. May 7, 2010. http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File/EPA

- SAB

- 10

- 007

- unsigned.pdf

.

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The maximum impact was compared to multiple short

- term health benchmarks for the chemical being assessed to determine if a possible acute health risk might exist. These benchmarks are d escribed in section 2.6 of the Final Risk Assessment Report in the project dockets.

Based on industry

- specific information, we determined that a refined emissions multiplier of 3 better represents the peak hourly emission rates for the Mineral Wool Produc tion source category. (See acute effects memorandum in the docket for a detailed description of how the refined emissions multiplier was developed for the Mineral Wool Production source category: EPA

- HQ

- OAR

- 2010

- 1041

- 0022). For the Wool Fiberglass Manufact uring source category data were not available to develop an industry specific refined emissions multiplier, therefore, the default emissions multiplier of 10 was used. In the Wool Fiberglass risk assessment, we relied upon the SAB guidance that the 10

- fold factor was recommended because it represented a level that is amply conservative in the absence of such information. Also, based on an analysis of data on short

- term emission rates relative to long

- term emission rates , the EPA has determined that the tenf old ratio assumption for short

- term releases is protective, and that the facilities for which it may underestimate event releases may tend to be smaller emitters. See Appendix 4 o f the document titled “Residual Risk Assessment for the Mineral Wool Producti on and Wool Fiberglass Manufacturing Source Categories in Support of the June 2015 Final Rule

, ” found in the docket for this rulemaking, for a detailed discussion of this analysis. We therefore disagree with the commenters on their characterization of the acute risk factor of 10 for wool fiberglass as insufficient.

4. Comment: According to one commenter (1042

- 0121/1042

- 0347), the EPA‘s multipathway risk assessment fell short because the EPA did not use “allowable” emissions for this assessment and the proposed rule shows multipathway risks that are 60 times greater than the EPA‘s threshold. The commenter stated that the EPA acknowledged in its 2014 Risk Assessment that the emissions allowed by the standard may be up to 3 times greater than actual emissions for phenol, methanol, and formaldehyde, such that the HQ of 30 could be 3 times higher based on allowable emissions. The commenter stated that by using actual emissions, the EPA’s analysis is likely to be an underestimate of the health risks from multipathway routes of exposure. The commenter supports the EPA’s use of “allowable” as well as “actual” emissions to assess inhalation risk.

Response : Consistent with previous risk assessments, the EPA considers both allowable and actual emissions in assessing chronic risks under CAA section 112(f)(2). (See, e.g., National Emission Standards for Coke Oven Batteries (70 FR 19998

- 19999, April 15, 2005); proposed and final National Emission Standards for Organic Hazardous Air Pollutants from the Synthetic Organic Chemical Manufacturing Industry (71 FR 34428, June 14, 2006, and 71 FR 76603, December 21, 2006). This approach is both reasonable and consistent with the flexibility inherent in the Benzene NESHAP framework for assessing acceptable risk and ample margin of safety . As a general matter, modeling allowable emission levels is inherently reasonable since this reflects the maximum level sources could emit and still comply with national emission standards. But it is also reasonable to consider actual emissions, where suc h data are available, in the acceptable risk and ample margin of safety (AMOS) analyses. See National Emission Standards for Coke Oven Batteries, 70 FR 19992, 19998 (April 15, 2005). The commenter

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claims that limiting our review to actual emissions would b e inconsistent with the applicability section of p art 63 rules. As explained, however, we did not limit our review to actual emissions.

The commenter also urged the agency to rely on allowable emissions , which we estimate to be three times the actual emi ssions, for the purpose of our acute assessment. The commenter indicated that the estimated maximum acute HQ of 30 (REL) would then be three times higher. The use of allowable emissions was not considered due to the conservative assumptions used to
gauge w orst

- case potential acute health effects. The conservative assumptions built into the acute health risk screening analysis include: (1) use of peak 1

- hour emissions that are, on average, 10 times the annual average 1

- hour emission rates; (2) that all emiss ion points experience peak emissions concurrently; (3) worst

- case meteorology (from 1 year of local meteorology); and (4) that a person is located downwind at the point of maximum impact during this same 1

- hour period. Thus, performing an acute screen base d on allowable emissions would be overly conservative and at best, of questionable utility to decision makers.

5. Comment: One commenter (1041

- 0081) stated that the EPA should find the acute health risk from Wool Fiberglass and Mineral Wool to be unacceptable . For both Wool Fiberglass and Mineral Wool, the commenter noted that the EPA’s assessment found an acute risk of 30 for Wool Fiberglass, and 8 for Mineral Wool. The commenter challenged the EPA’s consideration of a HQ below 1 as safe and argued that the E PA should find the health risk from both source categories to be unacceptable under CAA section 112(f)(2).

The commenter stated that the EPA has a presumption that an HQ below 1 is safe, that the EPA has stated that a HQ less than or equal to one indicates that adverse noncancer effects are not likely to occur, and that exposure below that threshold level is sa fe.

The commenter added that the EPA did not adequately explain why the formaldehyde risks were found to be acceptable although they are 30 times higher than the threshold for Wool Fiberglass, and 8 times the threshold for Mineral Wool.

Response: The high est acute risk is based on the reference exposure level (REL) is 20 (formaldehyde) for Mineral Wool Production facilities and is 30 (formaldehyde) for Wool Fiberglass Manufacturing facilities. As explained in our 2011 proposal, w e proposed to find the risk acceptable after consideration of various factors, including that the one mineral wool facility is located in a rural area with a small population, that the HQ estimates for formaldehyde based on the AEGL

- 1 and ERPG

- 1 values for this facility are at 1 and because the acute modeling is a
worst

- case scenario. With respect to the wool fiberglass manufacturing source category, we explained that the maximum acute HQ value based on the REL for formaldehyde could exceed a value of 1 at a total of 7 facilities wit h one facility indicating the potential to have an H Q up to 30. We further explained that this maximum worst

- case acute impact corresponds to maximum HQ of 1 based on the AEGL

- 1 and ERPG

- 1 levels for formaldehyde. We proposed to find the risk acceptable af ter consideration of various factors, including that the HQ estimates for formaldehyde based on the AEGL

- 1 and ERPG

- 1 values for these facilities are at 1 and because the acute modeling is a worst

- case scenario.

We note that the REL value is not a concentr ation at which health effects are expected to be observed. That is, the REL is defined as “the concentration level at or below which no adverse

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health effects are anticipated for specified exposure duration

. ” Moreover, we note that the acute risk assessmen t is a worst case assessment. For example, the acute assessment assumes worst

case meteorology, peak emissions and an individual being located at the site of maximum concentration for an hour. Taken together, the EPA does not believe that in all RTR review s, HQ values must be less than or equal to 1. Rather, the EPA finds that acute risks must be judged on a case by case basis in the context of all the available health evidence and risk analyses.

To better characterize the potential health risks associated with estimated acute exposures to HAP, and in response to a key recommendation from the SAB’s peer review of the EPA’s RTR risk assessment methodologies, 4 we generally examine a wider range of available acute health metrics ( e.g., RELs, AEGLs) than we do for our chronic risk assessments. This is in response to the SAB’s acknowledgement that there are generally more data gaps and inconsistencies in acute reference values than there are in chronic reference values. In some cases, when Reference Value Arrays 5 for HAP have been developed, we consider additional acute values (i.e., occupational and international values) to provide a more complete risk characterization. As discussed in the preamble to the proposed OSWRO rule (79 FR 37857, July 2, 2014), the expos ure guidelines the EPA considers depends on which exposure guidelines are available for the various hazardous air pollutants emitted. The EPA uses AEGL and ERPG values (when available) in conjunction with REL values (again, when available) to characterize potential acute health risks. However, it is often the case that HAP do not have all of these acute reference benchmark values. In these instances, the EPA describes the potential acute health risk in relation to the acute health values that are available. Importantly, when interpreting the results, we are careful to identify the benchmark being used and the health implications associated with any specific benchmark being exceeded. By definition, the acute CA

- REL represents a health

protective level of expo sure, with no risk anticipated below those levels, even for repeated exposures; however, the health risk from higher

- level exposures is unknown. Therefore, when a CA

- REL is exceeded and an AEGL

- 1 or ERPG

- 1 level is available (i.e., levels at which mild eff ects are anticipated in the general public for a single exposure), we have used them as a second comparative measure. Historically, comparisons of the estimated maximum off

- site one

hour exposure levels have not been typically made to occupational levels f or the purpose of characterizing public health risks in RTR assessments. This is because occupational ceiling values are not generally considered protective for the general public since they are designed to protect the worker population (presumed healthy a dults) for short duration (<15 minute) increases in exposure 6

. As a result, for most chemicals, the 15

- minute occupational ceiling values are set at levels higher than a one

- hour AEGL

- 1, making comparisons to them irrelevant unless the AEGL

- 1 or ERPG

- 1 lev els are exceeded (U

. S

. EPA 2009). Such is not the case when

4 The SAB pe er review of RTR Risk Assessment Methodologies is available at: http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771 F00668381/$File/EPA

- SAB

- 10

- 007

- unsigned.pdf

. 5 U.S. EPA. (2009) Chapter 2.9 Chemical Specific Reference Values for Formaldehyde in Graphical Arrays of Chemical

- Specific Health Effect Reference Values for Inhalation Exposures (Final Report). U.S. Environmen tal Protection Agency, Washington, DC, EPA/600/R

– 09/061, and available on

- line at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=211003

. 6 U.S. EPA. (2009) Chapter 2.9 Chemical Specific Reference Values for Formaldehyde in Graphical Arrays of

Chemical

- Specific Health Effect Reference Values for Inhalation Exposures (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600 /R

- 09/061, and available on

- line at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=211003

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comparing the available acute inhalation health effect reference values for formaldehyde (U

. S

. EPA 2009).

6. Comment: One commenter (1041

- 0078/1042

- 0119) asserted that, by applying the outdated Integ rated Risk Information System ( IRIS ) dose

- response values in determining formaldehyde inhalation exposure risk, the EPA is not basing the proposed rule on the best available science. The commenter urged the EPA to revise the Proposed Rule to accurately convey the best available science and a weight

- of

- evidence approach in compliance with the Information Quality Act ( IQA ) Guidelines and Executive Order 13563. In particular, the commenter argued that the EPA should reject the 1991 IRIS dose

- response value and incorporate the Chemical Industry I nstitute of Toxicology (CIIT, 1999) cancer dose

- response value for formaldehyde. The commenter noted that President Obama issued Executive Order 13563, requiring agencies to improve regulation and regulatory review. According to the commenter, the EPA used the 1991 IRIS value without conducting a comprehensive review of the body of research that may suggest an alternative value is supported by the best available science.

The commenter argued that U.S. Court of Appeals for the D.C. Circuit, in Chlorine Chemi stry Council v. EPA , 206 F.3d 1286 (D.C. Cir. 2000), further underscored the importance of rulemaking “on the basis of the best available science at the time of the rulemaking.” Id . at 1291 (emphasis in original). In holding that the best available science is the science available at the time of rulemaking, the commenter noted that the court unanimously rejected the EPA’s contention that it would defer the application of the best available science until after input from the SAB on the carcinogenic mode of a ction of chloroform. “The word ‘available’ would be senseless if construed to mean ‘expected to be available at some future date.’” Id . Similarly, the commenter stated that the research and data considered in the NAS Report of the Draft IRIS Assessment sho uld be incorporated into this rulemaking, and that the EPA has illegally deferred application of the best available science.

Response: In 2002 for this rule, and at various dates for other rules, we have complied with the IQA which requires us to “issue guidelines” to ensure and maximize data quality. We disagree with the commenter that scientific information used in the EPA risk assessme nts does not adhere to a rigorous standard of quality. The EPA has an approach for selecting the most appropriate and scientifically defensible health benchmarks and, in general, this approach places greater weight on the EPA derived health benchmarks than those from other authoritative bodies. 7 The approach of favoring the EPA benchmarks (when they exist) has been endorsed by the SAB and ensures the use of values most consistent with well

- established and scientifically

based EPA science policy. We also dis agree with the commenter that the EPA considers the CIIT value as a viable dose response value to be used in EPA risk assessments. In 2004, the EPA determined that the CIIT cancer dose

- response value for formaldehyde (5.5 x 10

- 9 per microgram per cubic met er, μg /m 3 ) was based on better science than the IRIS dose

- response value (1.3 x 10

-
5 per μg/m 3 ), and we switched from using the IRIS value to the CIIT value in risk assessments supporting regulatory actions. Subsequent research published by the EPA suggest ed that the CIIT model was not appropriate and in 2010 EPA returned to using 1991 IRIS value, which is more health protective ( U.S. EPA. 2010. Memorandum from Peter Preuss to Steve Page entitled,

7 http://www.epa.gov/ttn/atw/nata1999/99pdfs/healtheffectsinfo.pdf

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“Recommendation for Formaldehyde Inhalation Cancer Risk Valu es” January 22, 2010. ) . The EPA is currently revising the formaldehyde IRIS assessment and in the interim, we will present findings using the 1991 IRIS value as a primary estimate, and may also consider other information as the science evolves. This approa ch is consistent with the EPA’s information guidelines and fully compliant with the IQA.

The case cited by the commenter ( Chlorine Chemistry Council v. EPA ) is totally inapplicable to this circumstance. The rule in Chlorine Chemistry Council was issued und er the Safe Drinking Water Act, which statutorily mandates the use of the “best available science.” There is no such requirement under the CAA . But even if there were, EPA has fully and reasonably explained its decision to use the best available science in this rulemaking.

7. Comment: One commenter (1041

- 0081) stated that the EPA should find the chronic

non

- cancer risk from Wool Fiberglass and Mineral Wool to be unacceptable. The commenter believes the EPA has underestimated the risk by considering a target organ specific hazard index ( TOSHI ) below 1 as acceptable. For example, the commenter did not agree that the EPA adequately accounted for the greater risk to children due to early exposure, facility

- wide risk or cumulative toxic air health risk and did not consider impacts that are occurring above the critical dose in the development of the TOSHI.

The commenter pointed out that the EPA found the chronic non

- cancer risk (TOSHI) ( 0.5 for w ool f iberglass and 0.1 for m ineral w ool

, based on allowable em issions ) to be acceptable. The commenter recommended that the TOSHI should be no higher than 0.2, echoing an internal EPA draft memo randum

.
The commenter further asserted that even a 0.2 contribution should not be assumed to be protective, when many local communities have already experienced a long history of air emissions and continue to be exposed to emissions from many sources, and the EPA should consider an additional safety factor to reduce this risk further.

Response: First we would point out that, f or the final rule, the chronic noncancer TOSHI is 0.1 for both categories.

Second, w e disagree with the comment that any TOSHI value greater than 0.2 should be considered unacceptable. We note that pollutant

- specific reference concentrations (RfCs) are n ot absolute thresholds, but estimates of chronic inhalation exposures at or below which health effects would not be expected to occur, including in sensitive subgroups. We further note that these RfCs are developed using a health

- protective approach (see u ncertainty discussion in risk assessment document section 4.2), that TOSHI values of 1 or less are (like RfC levels) generally considered to carry no appreciable risk of adverse health effects and that there is generally no need to compound this protection by suggesting that any source category maximum TOSHI value would need to be at or below 0.2 before we would consider it to be acceptable.

We generally draw no bright lines of acceptability regarding cancer or noncancer risks from source category HAP emiss ions. It is always important to consider the specific uncertainties of the emissions and health effects information regarding the source category in question when deciding exactly what level of cancer and noncancer risk should be considered acceptable. In

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addition, the source category

- specific decision of what constitutes an acceptable level of risk should be a holistic one; that is, it should simultaneously consider all potential health impacts

-- chronic and acute, cancer and noncancer, and multipathway

- - along with their uncertainties, when determining the acceptable level of source category risk. In other words, we look at the risk numbers within the context of uncertainty associated with emissions and health benchmark values. The Benzene NESHAP decisio n framework of 1989 acknowledged this; in today’s world, such flexibility is even more imperative, because new information relevant to the question of risk acceptability is being developed all the time, and the accuracy and uncertainty of each piece of inf ormation must be considered in a weight

- of

- evidence approach for each decision. This relevant body of information is growing fast (and will continue to grow even faster), necessitating a flexible weight

- of

- evidence approach that acknowledges both complexit y and uncertainty in the simplest and most transparent way possible. While this challenge is formidable, it is nonetheless the goal of the EPA’s RTR decision

- making, and it is the goal of the risk assessment to provide the information to support the decisi on

- making process.

Finally, we note that the commenter’s source for its statement that default limits for a HI should or must be established at 0.2 rests on an unsigned, internal and deliberative EPA staff memorandum that was neither adopted as agency pol icy nor reviewed by either the public or any peer review body and, consequently, carries no precedential weight.

8. Comment: Two commenters (1041

- 0080/1042

- 0120 and 1042

- 0118) stated that the EPA does not have authority to consider “total facility” emissions in conducting the residual risk assessments for a given source category. The commenter argued that it would be impossible for the EPA to fulfill its unambiguous obligation for CAA section 112(f) standards to protect public health with an ample margin of sa fety in cases where facilities contain sources in a category where the 8

- year deadline for conducting the CAA section 112(f) risk review precedes the adoption of MACT standards for other sources at the facilities. Both c ommenter s added that CAA section 112 (f)(2)(A) requires the EPA to promulgate standards on a source category basis. One com menter (1041

- 0080/1042

- 0120) continued that this provision unambiguously requires the CAA section 112(f) risk assessment to be focused exclusively on “emissions from a so urce in the category or subcategory”, asserting that the EPA does not have authority to consider emissions from any sources other than those in the source category or subcategory under review at that time.

Response: First, we point out that for mineral woo l and wool fiberglass facilities

, no significant sources of HAP were identified that are outside the source categories covered by these standards. Therefore, separate facility

- wide risk estimates were not determined for the Mineral Wool Production or the W ool Fiberglass Manufacturing Source Categories.

Secondly, w e disagree that examining facility

- wide risk in a risk assessment conducted under CAA section 112(f) exceeds the EPA’s authority. The development of facility

- wide risk estimates provides additional information about the potential cumulative risks in the vicinity of the RTR sources, as one means of informing potential risk

- based decisions about the RTR source category in question. Whi le we recognize that, because these risk estimates are derived from facility

- wide emissions estimates which have not generally been subjected to the same level of engineering review as the source category emission estimates, they may be less certain than o ur

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risk estimates for the source category in question, but they remain important for providing context as long as their uncertainty is taken into consideration in the process.

Section 112(f)(2) of the CAA expressly preserves our use of the two

- step proce ss for developing standards to address residual risk and interpret “acceptable risk” and “ample margin of safety” as developed in the Benzene NESHAP (54 FR 38044, September 14, 1989). In the Benzene NESHAP, the EPA rejected approaches that would have manda ted consideration of background levels of pollution in assessing the acceptability of risk, concluding that “...comparison of acceptable risk should not be associated with levels in polluted urban air. With respect to considering other sources of risk from b enzene exposure and determining the acceptable risk level for all exposures to benzene, the EPA considers this inappropriate because only the risk associated with the emissions under consideration is relevant to the regulation being established and, conseq uently, the decision being made.” (54 FR 38044, 38061, September 14, 1989).

Although not appropriate for consideration in the determination of acceptable risk, we note that background risks or contributions to risk from sources outside the source category under review could be one of the relevant factors considered in the AMOS determination, along with cost and economic factors, technological feasibility, and other factors. Background risks and contributions to risk from sources outside the facilities unde r review were not considered in the AMOS determination for this source category, mainly because of the significant uncertainties associated with emissions estimates for such sources. Our approach here is consistent with the approach we took regarding this issue in the Hazardous Organic NESHAP (HON) RTR (71 FR 76603, December 21, 2006), which the court upheld in the face of claims that the EPA had not adequately considered background ( NRDC v. EPA , 529 F.3d 1077 (D.C. Cir. 2008)). In our November 25, 2011 pro posal, we explained that for these source categories, there are no other significant HAP emissions sources present at wool fiberglass manufacturing and mineral wool production facilities beyond those included in the source category. We also explained that all significant HAP sources have been included in the source category risk analysis. We therefore concluded that the facility wide risk is essentially the same as the source category risk and that no separate facility wide analysis was necessary. (76 FR 72 783, November 25, 2011). Our evaluation of facility

- wide risks did not change our decisions under CAA section 112(f)(2) about acceptability and ample margin of safety of the risks associated with the mineral wool and wool fiberglass source categories.

9. Com ment: One commenter (1041

- 0081/1042

- 0347) was concerned that the EPA is assessing noncancer hazards for lead solely through reliance on the 2008 National Ambient Air Quality Standards ( NAAQS ) for lead, which the commenter believes is not protective enough because the NAAQS was created to protect the average exposed member of the population from

an intelligence quotient ( IQ ) point loss above 2 points and only must satisfy the test to provide an “adequate margin of safety.” The commenter added that the NAAQS was also designed to address only a single pollutant (elemental lead). In contrast, the commenter observed that CAA section 112(f)(2) requires the EPA to assess and address health risk and to create an “ample margin of safety to protect public health”, and that lead can interact with other pollutants, such as arsenic, to cause greater harm than lead exposure alone. The commenter (1042

- 0347) further argued that EPA’s use of the NAAQS is unlawful and arbitrary due to the EPA’s refusal to consider or address t he most recent data that show health effects in children at exposure levels

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lower than the lead NAAQS: Center for Disease Control (CDC) decrease in the lead exposure level from 10 to 5 micrograms per deciliter ( μg/dL ) ; California’s benchmark shows that inc reases in blood

- lead level of 1.0 μg/dL can correlate to loss of 1 IQ point; Children’s Health Protection Advisory Committee (CHPAC) recognition that loss of 1 IQ point can occur at 0.01 μg/dL; CHPAC recommendation of protecting children from ambient lead concentration of 0.02 μg/m3;CHPAC evidence showing a link between lead levels in maternal blood and low birth weight. The commenter concluded that rather than only relying on the NAAQS to assess health risk from lead, the EPA should use all of the best ava ilable, most current information, including California‘s lead health benchmark.

Response: We disagree with the comment that the lead NAAQS was designed to protect the average exposed member of the population from an IQ loss above 2 points. The lead NAAQS primary standard targets protection to the most susceptible group in the human population

– children

– and is designed to protect against adverse effects to children’s most sensitive organ system

– the developing neurological system. (See 73 FR at 66975, 6 6976.) It is specifically targeted at those children living near major sources of lead, such as secondary smelters. (See 73 FR at 67002/3

, “in applying the evidence

- based framework, we are focused on a subpopulation of U.S. children, those living near air sources and more likely to be exposed at the level of the standard”; to the same effect see 73 FR 67000/3

-- “The framework in effect focuses on the sensitive subpopulation that is the group of children living near sources and more likely to be exposed at th e level of the standard. The evidence

- based framework estimates a mean air

- related IQ loss for this subpopulation of children; it does not estimate a mean for all U.S. children”; 73 FR 67005/1

-- “the air

- related IQ loss framework provides estimates for the mean air

- related IQ loss of a subset of the population of U.S. children, and there are uncertainties associated with those estimates. It provides estimates for that subset of children likely to be exposed to the level of the standard, which is generally ex pected to be the subpopulation of children living near sources who are likely to be most highly exposed.”)

. In addition, in reviewing and sustaining the lead primary NAAQS, we note that the D.C. Circuit specifically noted that the rule was targeted to prot ect children living near lead sources: “EPA explained that the scientific evidence showing the impact of lead exposure in young children in the United States led it ‘to give greater prominence to children as the sensitive subpopulation in this review’ and to focus its revision of the lead NAAQS on the ‘sensitive subpopulation that is the group of children living near [lead emission] sources and more likely to be exposed at the level of the standard.’ Given the scientific evidence on which it relied, the EPA ’s decision to base the revised lead NAAQS on protecting the subset of children likely to be exposed to airborne lead at the level of the standard was n ot arbitrary or capricious.” Coalition of Battery Recyclers , 604 F.3d at 618.

In response to the commen t that the EPA is required to assess the combined effect of a source category on the most exposed person, we agree and consider our analysis to have done this. The approach used to calculate chronic non

- cancer risks, developing the target

- organ specific ha zard index, specifically considers the combined effect of multiple pollutants on the same target organ. Any new scientific information concerning lead will be reviewed in accordance with the next NAAQS review process.

The commenter also makes the legal arg ument that the primary lead NAAQS provides an “adequate” margin of safety, but that CAA section 112(f)(2) requires that a residual risk standard provide an “ample” margin of safety, reasoning from this that a NAAQS cannot just be

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substituted as the measure for evaluating acceptability of risk and that some greater level of protection is required. The EPA disagrees with the commenter that CAA section 112(f)(2) requires that in all cases standards must be more protective than what is achieved by attainment of a primary NAAQS. Nothing in CAA section 112(f)(2) requires a conclusion that a standard that results in attainment of a primary NAAQS might not also in fact provide an ample margin of safety to protect public health. Further, to the extent the commenter’s argument rests on the difference between ‘adequate’ and ‘ample’ margin of safety, the argument is misplaced. 8 The EPA is considering the primary lead NAAQS

-- which incorporates an adequate margin of safety

-- merely to determine whether lead risks from ai r

- borne lead from Mineral Wool Production or Wool Fiberglass Manufacturing facilities are acceptable or unacceptable. The actual margin

- of

safety determinations for this rule are conducted in accord with the two

- step framework set forth in the Benzene NESH AP and the en banc opinion in the D.C. Circuit’s ruling in the Vinyl Chloride case. See not only Vinyl Chloride , 824 F.2d 1146, 1165

- 66 (D.C. Cir. 1987), but also NRDC v. EPA , 902 F.2d 962, 973

- 74 (D.C. Cir. 1990) (distinguishing the NAAQS process, whereby the margin of safety analysis is incorporated as part of the standard without a two

- step analysis, from residual risk determinations). 9 Using that framework, with its consideration of costs, cost

- effectiveness, technological feasibility, and other factors set out in the Benzene NESHAP, at proposal we did not identify any additional controls beyond those that would need to be implemented to ensure an acceptable level of risk with an ample margin of safety to protect public health.

Regarding the comment that the NAAQS does not account for combined impacts from multiple source exposure, refer to comment number 15 for the EPA’s response to the issue of multiple source exposure.

10. Comment: One commenter (1041

- 0081) stated that the EPA should assess health risk fro m all pollutants, even where it has no current reference value, and must use an uncertainty factor to make up for the lack of a reference value. Specifically, the commenter noted that the docket shows that the EPA has no human health reference value for HF

, trivalent chromium, antimony, or mercury. According to the commenter, it appears that the EPA did not account for the health risks posed by these pollutants, which is irrational and unlawful.

The commenter stated that the EPA did not identify the pollut ants for which reference values are not available or how the EPA has sought information it could use to address the data gaps. The commenter further stated that the EPA did not provide a transparent discussion that could inform public comment in a meaningf ul way on this issue, as required by 42 U.S.C. § 7607(d). The commenter stated that the EPA may not treat risk as zero for a HAP simply because it has no reference value for the health risk of the HAP. The commenter argued that the EPA must address the unc ertainty associated with data gaps in its risk analysis by selecting a health protective value based on information it does have or by using an uncertainty factor.

8 Indeed, the EPA’s utilization of a standard which also incorporates an adequate margin of safety to evaluate acceptability of risk, which is the first step in the CAA section 112(f)(2) residual risk assessment, is an added conservative (i.e. protective) el ement in its approach here.

9 The court was referring to the predecessor provision to the current CAA section 112(f), but its analysis is equally applicable to the revised provision.

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Response: The dose

- response values used for HF , antimony, gaseous divalent mercury and parti culate divalent mercury were omitted from the dose

- response value tables in the risk assessment document in error. The tables below show the dose

- response values for each of these pollutants that were used to evaluate human health risks.

Dose

- Response Va lues for Chronic Inhalation Exposure to Noncarcinogens

Pollutant CAS Number RfC (mg/m 3 ) Source 10 Antimony 7440360 2.0E

- 04 IRIS

- L Hydrofluoric acid 7664393 0.014 CAL Mercury (gaseous divalent) 201 3.0E

- 4 IRIS

- M Mercury (particulate divalent) 202 3.0E

- 4 IRIS

- M

Dose

- Response Values for Acute Exposure

Pollutant CAS Number AEGL

- 1 (1

- hr) (mg/m 3 ) AEGL

- 2 (1

- hr) (mg/m 3 ) ERPG

- 1 (mg/m 3 ) ERPG

- 2 (mg/m 3 ) REL Hydrofluoric acid 7664393 0.82 20 1.6 16 0.24

The only HAP emitted from the Mineral Wool Production and the Wool Fiberglass Manufacturing source categories for which dose

- response values are not available from sources in EPA’s hierarchy is trivalent chromium. Emissions of trivalent chromium were very low with 0.04 t ons per year (t py ) emitted f rom mineral wool facilities and 0.05 tpy emitted from wool fiberglass facilities.

In SAB’s May 7, 2010 response to the EPA Administrator 11

, the panel recommended that, for HAP that do not have dose

- response values from the EPA’s list, the EPA should consider and utilize, as appropriate, additional sources for such values that have undergone adequate and rigorous scientific peer review. The SAB pa nel further recommended that the inclusion of additional sources of dose

- response values into the EPA’s list should be adequately documented in a transparent manner in any residual risk assessment case study. We agree with this approach and have considered other sources of dose

- response data when conducting our risk determinations under RTR. However, in some instances , such as for trivalent c hromium, no sources of information beyond the EPA’s list are available.

It is important to note, that for the Miner al Wool Production source category, carbonyl sulfide (COS) is emitted from cupolas and COS does not have an IRIS reference value. In this case, we consulted the available research literature and found a series of studies that allowed us to derive of a chro nic noncancer screening level of 0.163 mg/m 3 for COS based on a No Observed Adverse Effects Level of 200 parts per million by volume ( ppm v) for lesions and

10 The descriptors L (low), M (medium), and H (high) have been added for I RIS RfC values to indicate the overall level of confidence in the RfC value, as reported in IRIS.

11 The SAB peer review of RTR Risk Assessment Methodologies is available at: http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File/EPA

- SAB

- 10

- 007

- unsigned.pdf

.

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neurophysiological alteration in rodents. 12
, 13
, 14 The EPA agrees that we should ultimately develop toxi city values for all HAP utilizing all credible and relevant toxicity information. The need to update assessments with newly available data as well as the need to complete toxicological assessments for all HAP lacking dose

- response assessments further incre ases the importance of a gency activities to streamline and fully utilize the EPA’s already overloaded IRIS program. To that end, the EPA has always prioritized for future IRIS assessments those HAP without dose

- response values but with the greatest potenti al for public exposure. As a result of this prioritization, while not all HAP may have scientifically accepted dose

- response values that can be used in residual risk assessments, it is clear that the vast majority of HAP which might carry the potential to significantly impact the results of residual risk assessments do, in fact, have credible dose

- response values. Thus, while we are not yet at the point where all HAP have dose

response values, we are generally capable of deriving reasonable risk estimates f or those HAP which dominate the risks from any one source category. In the course of each residual risk assessment, should we encounter HAP without dose

- response values which carry the potential to create significant risks, we shall clearly point those out as uncertainties and target them for future IRIS assessments. Moreover, as additional dose

- response values become available, the EPA will incorporate these dose

- response values into future risk assessments.

11. Comment: One commenter (1041

- 0081) stated that i t was not clear whether there are HAP missing from the EPA’s risk assessments for wool fiberglass and mineral wool. The commenter further stated that it was not clear whether the EPA’s health risk assessments include the currently uncontrolled emission poi nts for which the EPA proposed to set standards. The commenter also asked for confirmation that the EPA has assessed the health risk for all emitted HAP.

The commenter cited CAA section 112(f)(2) text that instructs EPA to assess health risk for “each cat egory or subcategory of sources,” and the commenter interpreted this text to mean “all HAP emissions and emission points, not just the emission points that the CAA section 112(d) standard previously covered.”

Response: The EPA has complied with CAA sectio n 112(f)(2) by assessing the health risk for all HAP and emission points for these two categories for which emissions data and dose

response value data were available. As indicated above, EPA cannot determine risk values for HAP that do not have dose

- respo nse values available, such as for trivalent c hromium. Refer to the previous response for further discussion of the EPA’s approach to addressing HAP associated with the wool fiberglass manufacturing and mineral wool production source categories where dose

- r esponse values were not available to assess risk.

12 Morgan, D.L., Little, P.B., Herr, D.W., Moser, V.C., Collins, B., Herbert, R., Johnson, G.A., Maron pot, R.R., Harry, G.J., and Sills, R.C.: Neurotoxicity of carbonyl sulfide in F344 rats following inhalation exposure for up to 12 weeks. Toxicol. Appl. Pharmacol. 200(2):131

- 145, 2004.

13 Herr, D.W., Graff, J.E., Moser, V.C., Crofton, K.M., Little, P.B., M organ, D.L., and Sills, R.C.: Inhalation exposure to carbonyl sulfide produced altered brainstem auditory and somatosensory

- evoked potentials in Fischer 344N rats. Toxicol. Sci. 95(1):118

- 135, 2007.

14 Sills, R.C., Morgan, D.L., Herr, D.W., Little, P.B., Ge orge, N.M., Ton, T.V., Love, N.E., Maronpot, R.R., and Johnson, G.A.: Contribution of magnetic resonance microscopy in the 12

- week neurotoxicity evaluation of carbonyl sulfide in Fischer 344 rats. Toxicol. Pathol. 32:501

- 510, 2004.

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12. Comment: One c ommenter (1041

- 0 0 81) stated that an IRIS review is currently underway to update EPA’s toxicity information for formaldehyde, hexavalent chromium, and methanol, which are pollutants emit ted by these source categories. The commenter further stated that the EPA should use the best available scientific information from the IRIS review during the current rulemaking and that the EPA should take a more protective approach until these
reassessments are complete.

Response: T he dose

- response values that were used in this risk analysis for formaldehyde

, hexavalent chromium , and methanol are based on the curr ent peer reviewed IRIS values. The dose

- response value used for methanol was updated to reflect the September 2013 IRIS findings . At the time this analysis was performed these values were deemed to represent the best science and thus represent the most protective approach.

13. Comment : One commenter (1041

- 0081/1042

- 0121/1042

- 0347) added that the EPA should perform a multipathway risk assessment for all metals emitted by this source category, including arsenic, chromium, nickel, and manganese. The commenter noted that California OEHHA has recommended multipathway assessment for these metals based on scientifi c research, and the EPA should follow its lead instead of the 2003 Risk Assessment Guidance. The commenter provided additional information for each of these pollutants for the EPA’s consideration (e.g., California OEHHA’s recommended multipathway assessmen t for nickel, arsenic, manganese, and hexavalent chromium based on scientific research). The commenter concluded that the EPA simply may not assume that the ingestion and other multipathway risks are zero for these pollutants, because doing so when science shows otherwise results in an underestimate of the health risks of HAP emissions from this source category and is arbitrary and capricious.

Response : In the Air Toxics Assessment Library, we developed the current persistent and bioaccumulative HAP (PB

- HAP) list considering all of the available information on persistence and bioaccumulation (see http://www.epa.gov/ttn/fera/risk_atra_main.html ). This list was created by reviewing HAP identified as PB

- HAP by other EPA Program Offices (e.g., The Great Waters Program) and also used information from the PBT Profiler (see http://www.pbtprofiler.net). This list was peer

- reviewed by the SAB, and it is reasonable to use it in the RTR program. Based on these sources and the limited available information on the persistence and bioaccumulation of other HAP, we do not believe that the potential for multipathway risk from other HAP rises to the level of the PB

- HAP currently on the list.

14. Comment: O ne commenter (1042

- 0121/1042

- 0347) stated that the EPA must consider this science and update its risk assessment in each of the following ways before finalizing the rule:

• Adopt the OEHHA of the California Environmental Protection Agency child

protective sc ientific approach on cancer and other pollutants, and use at least an additional 10

- fold uncertainty factor to protect children in addition to the uncertainty factors it already uses, when a child

- specific reference value or vulnerability information is no t available. The commenter observed that Congress recognized this science in toxics legislation in 1996, the Food Quality Protection Act (FQPA) for

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pesticide chemical residue, where Congress used a ten

- fold margin of safety for infants and children.

• Follow the lead of OEHHA by using age

- dependent adjustment factors for all carcinogens emitted by this source, including naphthalene, polycyclic aromatic hydrocarbons ( PAHs ) and arsenic; use a 10

- fold adjustment factor to account for prenatal susceptibility to P OM; and use the OEHHA factors for prenatal susceptibility and exposures.

• Use the OEHHA child

- specific reference doses to assess chronic noncancer and acute health risk, where they are available.

Consult with multiple scientific bodies on the scientific ba sis of the proposed rulemaking, including multiple citations provided by the commenter in support of the commenter’s assertions about risks from POM, PAHs and arsenic.

The commenter also provided a table of comparisons between OEHHA child

- health reference values and those of EPA.

The commenter opined that the EPA did not provide a valid justification for not using the method developed by California’s Office of Environmental Health Hazard Assessment to assess the risks from nickel, arsenic, manganese, and h exavalent chromium.

Response: We disagree with the general comment that the EPA should adopt the Cal OEHHA methods to estimate cancer risk and non

- cancer hazard for specific pollutants. The EPA has an approach for selecting appropriate health benchmarks an d in general, this approach places greater weight on the EPA derived health benchmarks than those from other agencies (see http://www.epa.gov/ttn/atw/nata1999/99pdfs/healtheff ectsinfo.pdf ). Notably, this approach favoring EPA benchmarks (when they exist) over all others has been endorsed by the SAB. The EPA is currently evaluating whether it is appropriate to use specific benchmarks derived by the Cal OEHHA. We note that there are currently no such values for HAP inhalation, therefore their current utility would be limited to persistent and bioaccumulative PB

- HAP, which may be associated with non

- negligible ingestion exposures. The evaluation of the appropriateness of these values in the context of the RTR Program and EPA science policy is necessary prior to using these child

- specific reference doses (RfDs)

. We also disagree with the comment that a children’s default safety factor of 10 or more should be added to EPA’s reference values. In response to the 10X factor enacted by Congress in the Food Quality Protection Act (1996) 15 to the EPA non

- cancer referenc e value derivation, the

a gency evaluated their methods for considering children’s risk in the development of reference values. As part of their response, the U.S. EPA (i.e. the Science Policy Council and Risk Assessment Forum) established the RfD/RfC Techn ical Panel to develop a strategy for implementing the Food Quality Protection Act (FQPA) and examine the issues relative to protecting children’s health and application of the 10X safety factor. One of the outcomes of the Technical Panel’s efforts was an i n depth review of a number of issues related to the RfD/RfC process (U.S. EPA 2002). The most critical aspect in the derivation of a reference value

15 US Environmental Prote ction Agency, Pesticide: Regulating Pesticides. The Food Quality Protection Act (FQPA). 1996. Available at http://www.epa.gov/pesticides/regulating/laws/fqpa/backgrnd.htm

.

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pertaining to the FQPA has to do with variation between individual humans and is accounted for by a default uncertainty factor (UF

- H) when no chemical

- specific data are available. EPA reviewed the default UF for inter

- human variability and found the EPA’s default value of 10 adequate for all susceptible populations, including children and infants. The EPA also recommended the use of chemical

- specific data in preference to default uncertainty factors when available (US EPA, 1994, 2011) and is developing a gency guidance to facilitate consistency in the development and use of data

- derived extrapolation factors for RfCs and RfDs (U.S EPA, 2011). Additionally, the EPA also applies a database uncertainty factor (UF

- D) which is intended to account for the potential for deriving an under

- protective RfD/RfC as a result of an incomplete characterization of the chemical’s t oxicity. In addition to the identification of toxicity information that is lacking, review of existing data may also suggest that a lower reference value might result if additional data were available.

We acknowledge that population subgroups, including ch ildren, may have a potential for risk that is greater than the general population due to greater relative exposure and/or greater susceptibility to the toxicant. As explained in previous actions, including the final HON RTR (71 FR 76610

- 76611), the assessm ents we undertake to estimate risk account for this potential vulnerability. With respect to exposure, the risk assessments we perform implicitly account for this greater potential for exposure by assuming lifetime exposure, in which populations are

conser vatively presumed to be exposed to airborne concentrations at their residence continuously, 24 hours per day for a full lifetime, including childhood. With regard to children’s potentially greater susceptibility to non

- cancer toxicants, the assessments rel y on EPA (or comparable) hazard identification and dose

- response values which have been developed to be protective for all subgroups of the general population, including children. In the latest review 16 of the chronic reference value process EPA concluded that the EPA’s reference concentration (RfC) derivation processes adequately considers potential susceptibility of different subgroups with specific consideration of children, such that the resultant RfC values pertain to the full human population “includi ng sensitive subgroups,” a phrase which is inclusive of childhood. With respect to cancer, the EPA uses the age

- dependent adjustment factor approach referred to by the commenter, but limits the use of those factors only to carcinogenic pollutants that are known to act via mutagenic mode of action, in contrast to the OEHHA approach, which uses them across the board for all carcinogens regardless of mode of action (MOA). In lieu of chemical

- specific data on which age or life

- stage specific risk estimates or p otencies can be determined, default age dependent adjustment factors can be applied when assessing cancer risk for early

- life exposures to chemicals which cause cancer through a mutagenic MOA. With regard to other carcinogenic pollutants for which early

- li fe susceptibility data are lacking, it is the

a gency’s long

- standing science policy position that use of the linear low

- dose extrapolation approach (without further adjustment) provides adequate public health conservatism in the absence of chemical

- specifi c data indicating differential early

- life susceptibility or when the

16 U.S. EPA. A Review of the Reference Dose and Reference Concentration Processes. U. S. Environmental Protection Agency, Risk Assessment Forum, Washington, DC, EPA/630/P

- 02/002F, 2002.

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mode of action is not mutagenicity. 17 The basis for this methodology is provided in the 2005 Supplemental Guidance. 18

The estimated risks for this source category must also be considered in the context of the full set of assumptions used for this risk assessment. For example, we used a health

- protective assumption of a 70

- year exposure duration in our risk estimates; however, using the national average residency time of 12 years would reduce the estimate of risk by roughly a factor of 6. Our unit risk estimates for HAP are considered a plausible upper

- bound estimate; actual potency is likely to be lower and some of which could be as low as zero. After considering these and other factors, we c ontinue to consider the risks from emissions after application of the revisions to the NESHAP for this source category to provide an ample margin of safety (consistent with the Benzene NESHAP framework).

15. Comment : Two commenters (1041

- 0081/1042

- 0121 and 104 1

- 0081) opined that the EPA should assess the cumulative burden of exposures to multiple pollutants and sources via multiple pathways. To do this, the commenters suggested that the EPA include the interaction of multiple pollutants and account for exposure to multiple emissions sources including other emissions sources at the facilities and from other sources of toxic air pollutants in the area. Another commenter (1041

- 0 076) underscored the importance of considering other sources of HAP regardless of indust ry segment.

One commenter (1041

- 0081) stated EPA needs to assess the synergistic, carcinogenic, and other effects of different pollutants because multiple carcinogens work together to create a cancer risk greater than the single effect of any one pollutant . The commenter stated that EPA combines the risk for different pollutants in determining the cancer risk or MIR and also combines the chronic non

- cancer risk HQ for pollutants that work in a similar way or on the same organ system, to create a “target org an specific hazard index or TOSHI. The commenter asserted that EPA does not create a combined acute risk number that would represent the total
acute risk for all pollutants that act in a similar way on the same organ system or systems, similar to the chron ic TOSHI, and that without that, the full acute health risk is not accounted for.

One commenter (1041

- 0081/1042

- 0121) contended that, if a source category’s risk is between 1

- in

- 1 million and the presumptive limit on acceptability (currently 100

- in

- 1 milli on) and the source category is contributing risk along with numerous other source categories, then CAA section 112(f)(2) requires the EPA, and gives the EPA full authority, to include in its residual risk analysis the risk associated with the whole cumulat ive health burden on the people living near the source category, not just the future risk for the source category. According to the commenter, whole cumulative health burden includes the following impacts in addition to future health impact: (1) cumulative impacts over time (i.e., persistent, bioaccumulative HAP and health risk due to past exposure, which increases the current health risk) and (2) impacts from all HAP

- emitting sources in the local area. The commenter also suggested that, to account for thes e additional cumulative impacts including other sources, the EPA could incorporate an uncertainty

17 Id.

18 U.S. EPA. (2005), Supplemental Guidance for Assessing Susceptibility from Early

- Life Exposure to Carcinogens

. EPA/630/R

- 03/003F. Washington, DC. Av ailable online at: http://www.epa.gov/cancerguidelines/guidelines

carcinogen

- supplement.htm.

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factor into its residual risk analysis. The commenter also stated that this approach of accounting for cumulative risks in its residual risk analysis would be consistent with the SAB’s recommendation (made in May 2010), which stated that RTR assessments will be most useful to decision makers and communities if results are presented in the broader context of aggregate and cumulative risks, including background c oncentrations and contributions from other sources in the area.

Regarding cumulative impacts, one commenter (1041

- 0081/1042

- 0121) cited the CertainTeed facility in Kansas City. The commenter noted that the EPA recognized the potential for that facility to emit 913 pounds per year of chromium compounds, of which 840 pounds is hexavalent chromium. The commenter suggested that these data show that this one facility may have emitted 7 times 840 pounds (or over 5,000 pounds) hexavalent chromium into this one

com munity during the last 7 years. The commenter surmised that the EPA did not evaluate how long facilities have existed at their current locations and did not calculate the impact of their past emissions on the current health risk of the most

- exposed local c ommunities. The commenter recommended that the EPA aggregate people’s risk when deciding how much additional risk is acceptable for a single source category. The commenter added that for the CertainTeed facility the acceptable level of cancer, non

- cancer c hronic, and acute risk from the source category should be adjusted (e.g., divided by an uncertainty factor) based on the number of other facilities contributing HAP exposure risks, over a period of 7 years.

Regarding impacts from other sources, one comment er (1041

- 0081/1042

- 0121) alleged that the EPA used uncertainty as the basis for focusing the risk assessment on only the sources in the mineral wool and wool fiberglass source categories, and added that uncertainty is not a rational explanation for failing to address this important element of health risk. Where public health is concerned, the commenter believed that uncertainties require more conservative assessment and more protective action, rather than inaction. The commenter suggested that the EPA shoul d, at minimum, use an uncertainty factor to account for the greater health risk. The commenter argued that the EPA should follow the recommendations in the SAB Report stating that: “the Panel recommends that the Agency perform a sensitivity analysis to ide ntify the major uncertainties in both the human health and ecological risk assessments. The Agency should then proceed to: (1) explain them clearly in the risk characterization section and (2) take steps to reduce them.”

The commenter argued that EPA did n ot adequately assess facility wide risk and vicinity risks from nearby communities in developing a combined impacts assessment. Per the commenter, EPA should more adequately address children‘s health, multiple source exposure, and environmental justice fac tors in deciding what margin is needed to provide ‘ample’ protection for public health.

The commenter suggested that the EPA did not consider in its residual risk analysis the existing baseline (cumulative impacts from persistent, bioaccumulative HAP and h ealth risk due to past exposure) and impacts from all HAP

- emitting sources in the local area beyond the wool fiberglass and mineral wool source categories. According to the commenter, that type of cumulative impacts analysis is a routine consideration that is also required under other provisions of the CAA and other environmental statutes and would characterize a full risk assessment. The

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commenter alleged that the EPA did not fully consider such factors in this risk assessment, and therefore did not fulfil l its obligation to provide the legally required ample margin of safety.

Response: We have combined risk assessment results to the extent that it is appropriate to do so. We consider the effect of mixtures of carcinogens and use a TOSHI approach for our ch ronic noncancer assessments. We do not use a TOSHI approach for our acute analyses nor do we combine the results of our inhalation and multipathway assessments.

For the wool fiberglass and mineral wool manufacturing source categories, the EPA conducted assessments of the cumulative cancer risks from emitted carcinogens and the cumulative noncancer hazard indices from all emitted non

- carcinogens affecting the same target organ system for both the source category emissions. To address the effect of mixtures of carcinogens, our assessment used the guideline ’ s default assumption for mixtures of additivity of effects, and combine d the cancer risks by summing them using the independence formula in the mixtures guidelines. In assessing noncancer hazard from chronic exposures for pollutants that have similar modes of action or that affect the same target organ, we aggregated the HQ to provide a TOSHI. A TOSHI is defined as the sum of HQs for individual HAP that affect the same organ or organ system. All TOSHI calculations presented here were based exclusively on effects occurring at the “critical dose” (i.e., the lowest dose that produces adverse health effects). We also dis agree with the commenter’s assertion that additional quantitative assessment of risks from sources outside the source categories is required under the statute. The statute requires the EPA to provide the quantitative risk information necessary to inform RT R regulatory decisions, and to this end, the EPA conducts a comprehensive assessment of the risks associated with exposure to the HAP emitted by the source categories and supplements that with additional information that is available about other possible c oncurrent and relevant risks.

While the incorporation of additional background concentrations from the environment in our risk assessments (including those from mobile sources and other industrial and area sources) could be technically challenging, they ar e neither mandated nor barred from our analysis. In developing the decision framework in the Benzene NESHAP currently used for making residual risk decisions, the EPA rejected approaches that would have mandated consideration of background levels of pollut ion in assessing the acceptability of risk, concluding that comparison of acceptable risk should not be associated with levels in polluted urban air (54 FR 38044, 38061, September 14, 1989). Background levels (including natural background) are not barred f rom the EPA’s AMOS analysis, and the EPA may consider them, as appropriate and as available, along with other factors, such as cost and technical feasibility, in the second step of its CAA section 112(f) analysis. This assessment excludes background contri butions because the available data are of insufficient quality upon which to base a meaningful analysis.

As described in the risk assessment report (available in the docket for this action), we do not sum results of the acute noncancer inhalation assessmen t to create a combined acute risk number that would represent the total acute risk for all pollutants that act in a similar way on the same organ system or systems (similar to the chronic TOSHI). As noted in previous responses, the worst

- case acute screen is already a conservative scenario. That is, the acute screening scenario assumes worst

- case meteorology, peak emissions for all emission points occurring concurrently and an individual being located at the site of maximum concentration for an hour. Thus, as noted in section 2.7.2 of the Draft Residual Risk Assessment for the Mineral Wool

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Production and Wool Fiberglass Manufacturing Source Categories (Docket Item No. EPA

- HQ

OAR

- 2010

- 1042

- 0328), “because of the conservative nature of the acute inhalation scr eening and the variable nature of emissions and potential exposures, acute impacts were screened on an individual pollutant basis, not using the TOSHI approach.”

16. Comment: One commenter (1042

- 0347) disagreed with the EPA’s use of workplace benchmarks to ju stify that an HQ of 30 is acceptable because the workplace benchmarks do not protect the vulnerable populations (children, pregnant women, elderly, and those with health conditions).

Response: The commenter is responding to the EPA’s request for comment on whether the occupational values should be used in the interpretation of these worst

- case acute screening exposure estimates for these source categories. The EPA thanks the commenter for provid ing this feedback. In the preamble to the 2014 supplementary proposal, the EPA did not include workplace benchmarks as part of its discussion of risk, but rather relied on the HQ for only REL and AEGL

- 1. The EPA considered the workplace benchmarks in asses sing the acceptability of an HQ of 30, but did not determine acceptability based solely on this metric. In the preamble to the 2011 proposal (76 FR 71782, November 25, 2011), the EPA presented multiple HQ levels based on multiple acute dose

- response values , including acute REL, AEGL, ERPG, and the 15

- minute occupational ceiling values referred to by the commenter. The EPA used all such HQ values in assessing the risk associated with the wool fiberglass and mineral wool production industries. In the preamble cited above, the EPA acknowledged that, historically, comparisons of the estimated maximum off

- site one

- hour exposure levels have not typically been made to occupational levels for the purpose of characterizing public health risks in RTR assessments due
t o the fact that occupational ceiling values are not generally considered protective for the general public since they are designed to protect the worker population (presumed healthy adults) for short duration (< 15 minute) increases in exposure.”

17. Comment: One commenter (1042

- 0347) argued that the EPA’s proposed “acceptable” risk determination based on an HQ of 30 is arbitrary and capricious because this determination conflicts with the EPA’s recently proposed National Emission Standards for Hazardous Air P ollutants: Ferroalloys Production, 79 Fed. Reg. 60,238, 60,269

- 70 (October 6, 2014) that concluded an HQ of 40 contributed to the EPA’s determination that risk is unacceptable for that industry, when combined with high cancer risk.

Response: The commenter is referring to the maximum chronic non

- cancer TOSHI established as part of the EPA’s risk assessment conducted for the EPA’s review of the Ferroalloys Production NESHAP. In the EPA’s proposal cited by the commenter, the EPA specified in Table 8 of the pre amble (79 FR 60266, October 6, 2014) that the maximum chronic

non

- cancer TOSHI was 40 based on allowable emissions and 4 based on actual emissions, with an HQ (REL) of 1. In comparison, the EPA’s risk assessment supporting the EPA’s 2014 proposal for wool fiberglass manufacturing established a maximum chronic non

- cancer TOSHI of 0.5 based on allowable emissions and 0.2 based on actual emissions, with an HQ (REL) of 30. The commenter is asking the EPA to compare the TOSHI value of 40 generated for ferroalloy s to the HQ (REL) of 30 generated for wool fiberglass; however, these two values are not comparable because they represent two different measures of risk. A TOSHI, defined as the sum of HQ s for individual HAP that affect the same organ or organ system, is used for assessing noncancer

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hazards from chronic exposures. A n HQ based on an REL is used for assessing health risks from acute exposures. Therefore, the TOSHI of 40 for ferroalloys would better be compared to the TOSHI of 0.5 for wool fiberglass.

18. Comment: According to one commenter (1042

- 0121), the EPA’s risk review failed to assess the health risk from malfunctions or violations of the existing MACT standard because facilities may violate that standard and emit HAP at a level beyond what is “allow able” under the rule. The commenter noted that the CAA specifically requires EPA to base its risk analysis on the highest potential risk “to the individual most exposed to emissions from a source in the category or subcategory” (42 U.S.C. § 7412(f)(2)(A); § 7412(f)(1)(C))

. The commenter stated that the EPA must consider the full potential for health risk that will occur should sources emit above the level the CAA section 112(d) standard allows (e.g., due to control device failure), not just the risk based o n the amount of emissions that the standard would allow. In the commenter’s opinion, ignoring the potential for non

- compliance is equivalent to treating additional health risk caused by exceedances as zero, but the EPA knows that there is additional risk f rom malfunctions and violations and it cannot ignore that risk.

Response : We disagree with the commenter that emissions that exceed standards and are violations, whether or not they are caused by malfunction events, should be considered as part of the risk analysis for purposes of determining the sufficiency of pre

- existing standards, particularly when we are revising the standards to eliminate any excused periods of non

compliance during upset periods. The purpose of the risk review is to evaluate whether the emission limits

-- the “standards promulgated pursuant to subsection (d),” not the non

compliance with those standards ( CAA section 112(f)(2)(A))

-- should be made more stringent to reduce the risk posed after compliance with the underlying MACT stand ard. To the extent that a source is violating the underlying MACT standard, no tightening of the emission standard under the residual risk rule will avoid or militate against such violations. In other words, a source that is violating the emission standard promulgated under CAA section 112(d) would not be any more likely to be able to avoid such violations and comply with a different presumably more stringent standard promulgated under CAA section 112(f). Such events are violations and subject to enforcemen t by the EPA, the states or citizens, and an action for injunctive relief is the most effective means to address violations, whether or not they are caused by malfunctions, if an emissions event poses a significant health or environmental risk.

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

- case potential acute health effects. The conservative estimates built into the assessment include worst

- case meteorology, emissions at 10 times the maximum peak emission rate from all w ool f iberglass point sources simultaneously (a multiplier of 3 is used for m ineral

w ool sources) , and the sum of the maximum impact of each emission source, regardless of receptor location. Thus, even if we were to consider emissio ns that are in violation of the standard, we do not believe that they would result in any different level of control than we are promulgating here.

With regard to the failure of a control device, this would constitute a violation of the emission standard. The acute risk emissions factor is designed to account for fluctuations in emissions for facilities complying with the standards, not for facilities in non

- compliance. Therefore, it would be inappropriate to use the emissions factor suggested by the commen ter for

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purposes of determining whether the NESHAP’s current requirements are in need of revision under CAA section 112(f)(2).

19. Comment: One commenter (1042

- 0115f) asserted that the EPA’s Heath Risk Assessment is not conservative and additional analysis is needed because the EPA has insufficient data as demonstrated by how many years the plants operated before the EPA discovered the high emissions and how much the data vary.

Response: The EPA disagrees with the commenter that the EPA did not have sufficient data to establish standards for the wool fiberglass source category and to conduct its risk analysis. The EPA began developing the original NESHAP (subpart NNN) in 1996 and the final rule was promulgated on June 1, 1999. Subpart NNN includes PM emission l imits for glass

melting furnaces which serve as a surrogate for HAP metals, including chromium compounds. As part of the residual risk and technology review, the agency began collecting additional information related to wool fiberglass manufacturing in the 2008

– 2009 timeframe. Meetings with industry representatives and one of their trade associations (NAIMA) led to a voluntary survey being sent out in 2010. A CAA section 114 ICR was sent out in November 2011 to collect additional information and test data on all glass

- melting furnaces. The EPA had sufficient data to establish standards and conduct a risk assessment for all pollutants except methanol, phenol, and formaldehyde for RS manufacturing lines at wool fiberglass manufacturing facilities. As discuss ed in section V. H of the preamble to the final rule, we have issued an ICR under section 114 of the CAA to collect updated emissions and process information from the industry and we will analyze the ICR data and evaluate MACT limits for RS lines at wool fi berglass manufacturing facilities at a future date.

Uncertainty and the potential for bias are inherent in all risk assessments, including those performed for this rulemaking. Although uncertainty exists, our approach, which uses conservative tools and as sumptions, ensures that our decisions are appropriately health protective and environmentally protective. A discussion of the uncertainties in the RTR emissions datasets, dispersion modeling, inhalation exposure estimates and dose

- response relationships ca n be found in the residual risk assessment document in the rulemaking docket.

20. Comment : One commenter (1041

- 0 076) stated that the EPA, in assessing risks in the Oak Grove Neighborhood in Kansas City, Kansas (and other similarly situated neighborhoods across the country), should consider that residents are more likely to have 24/7 exposure to HAP than residents in geographic areas where the population is younger and more mobile, and where the discretionary income is higher and transportation is more accessibl e.
Response: Our residual risk characterization does make this health protective assumption that people will be in their home 24/7 for 70 years.

21. Comment : One commenter (1042

- 0115/1042

- 0120/1042

- 0300/1042

- 0348) alleged that potential errors in the EPA's risk and exposure assessment led the a gency to overestimate the risk from this source category.

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Response: The commenter did not provide any information or data to characterize the “potential errors” in the risk and exposure assessment conducted for the Mineral Wool Production or Wool Fiberglass Manufacturing source categories.

B. Ample Margin of Safety Analysis

22. Comment : Two commenters (1041

- 0081/1042

- 0121/1 042

- 0299 and 1042

- 0300/1042

- 0348) opined that, for both RTRs, the EPA should provide the analysis that was conducted to determine whether an ample margin of safety is achieved by the standard, as well as all options that were considered along with the emis sion reductions, the risk level of each option, and the cost of each option. One commenter (1042

- 0300/1042

- 0348) asked whether the EPA identified other limits that would have also provided an AMOS with far lower costs . One commenter (1042

- 0299) also believ ed that for wool fiberglass, the EPA should improve the AMOS analysis conducted for major sources and then apply that improved AMOS analysis to the proposed area source standards in order to consider and provide sufficient protection for public health.

On e commenter (1041

- 0081/1042

- 0121) stated that the EPA does not discuss how the proposed rule provides an ample margin of safety, describe the ample margin, present what are less expensive options, or discuss why the agency considers the margin of safety as “ample”. The commenter contended that the EPA is not authorized to put cost of controls above health of people, but that the EPA has done that because it did not adequately consider health impacts of the most

- exposed person. The commenter added that the E PA did not sufficiently explain how the cost

- based decision on the AMOS determination was made and that the EPA should have considered additional options for reductions. The commenter added that the EPA did not satisfy its own “ample margin of safety” test because it did not consider whether the proposed rules provide the maximum feasible protection against health risks for the greatest number of people, did not discuss or analyze what the maximum feasible protection would be, or how many people could be pr otected from a greater level of risk.

Response: We agree with the commenter that the agency did not provide an explanation of the analysis we conducted for the AMOS review in the 2011 and 2013 proposals. These proposals did not contain a discussion of opti ons for both the mineral wool and the wool fiberglass source categories, along with the costs, emission reductions, and associated risk of each option. In response to comments like this, f ollowing the 2011 and 2013 proposals, the EPA provided its analysis in the docket with the 2014 proposal . Our discussion and review of options can be found in the memoranda titled: “Mineral Wool RTR Ample Margin of Safety (AMOS)

– Analysis and Proposed Controls,” October 15, 2014 (EPA

- HQ

- OAR

- 2010

- 1041

- 0154); and Wool Fiber glass RTR Ample Margin of Safety

– Analysis and Proposed Controls,” October 15, 2014 (EPA

- HQ

- OAR

- 2010

- 1042

- 0334). For the Mineral Wool source category, the AMOS analysis did not identify any feasible options for increasing the ample margin of safety, consi dering cost and technical feasibility. For the Wool Fiberglass source category the AMOS analysis identified that reducing the operational life of the gas

- fired furnaces from 10 years to 7 years was the option that the EPA determined necessary to provide an ample margin of safety

. We disagree with the comment that the EPA did not sufficiently explain how the cost

based decision on the AMOS determination was made. As also explained in our November 2011

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proposal, the EPA may consider costs in its decision to s et standards under the ample margin of safety step of CAA section 112(f)(2). This is consistent with the approach set out in the Benzene NESHAP framework for assessing acceptable risk and ample margin of safety. As previously explained, section 112(f)(2) o f the CAA expressly preserves our use of the two

- step process for developing standards to address residual risk and interpret “acceptable risk” and “ample margin of safety” as developed in the Benzene NESHAP (54 FR 38044, September 14, 1989). We also
note that the U.S. Court of Appeals for the D.C. Circuit has affirmed this approach of implementing CAA section 112(f)(2)(A): NRDC v. EPA , 529 F.3d 1077, 1083 (D.C. Cir. 2008). Our cost considerations can be found in the memo randum “Wool Fiberglass RTR Ample Margin of Safety

– Analysis and Controls for the Final Amendments” , which is in the docket for this rulemaking

.

23. Comment : One commenter (1042

- 0300/1042

- 0348) opined that there is only one facility in the industry with elevated chrom ium emissions, such that all risk of chromium associated with this source category is attributable to the one facility that has unusually high emissions. The commenter suggested that the EPA consider the lower levels emitted by all other facilities to be an ample margin of safety to the risk posed by the one facility, and that the EPA address these elevated chromium emissions by addressing one facility’s high emissions, separate from this rulemaking.

Response: The EPA does not agree with the commenter that only one facility in the source category has elevated chrom ium emissions or that all risk of chromium associated with this source category is attributable to that facility. In our April 2013 proposal, we explained that
gas

- fired glass

- melting furnaces can emit higher levels of met al HAP as well as higher than expected levels of chr omium as a result of using high

- chromium refractories. (78 FR 22377, 79 FR 68024). As also documented in the memorandum “Chromium Emissions and Furnace Age” (EPA

- HQ

- OAR

- 2010

- 1042

- 0332), of the six gas

- fir ed furnaces at major sources tested, three furnaces emit chromium at levels higher than the proposed chromium limit, and two of these furnaces emit chromium at significantly higher levels. Further, as the EPA stated in the preamble to the April 15, 2013 pr oposal (78 FR 22379), the EPA has determined that it is possible that the lower

- emitting furnaces could emit higher levels of chromium, and that lower

- emitting furnaces could be replaced with other types of furnaces that emit higher levels of chromium. For further discussion of these conclusions, refer to the memorandum cited above, which discusses the EPA’s conclusion that chromium emissions increase with furnace age, and section IV.A of the preamble to the April 15, 2013 proposal (78 FR 22380), which disc usses the industry trend is to utilize oxyfuel gas

- fired furnaces, which have the highest potential for elevated chromium emissions. In our various proposals, we have also indicated that hexavalent chromium is the secondary risk driver. An MIR of 3

- in

- 1 mi llion was attributable to hexavalent chromium from the facility that contributes the highest risk. Therefore, in the final rule we are finalizing emission limits for chromium emissions from gas

- fired glass

- melting furnaces of 0.00025 pounds of total chromi um per ton of glass pulled to provide an ample margin of safety and prevent adverse environmental effects.

24. Comment: One commenter (1042

- 0300) opined that the existing risk does not warrant imposing the chromium emission limit in addition to the PM limit. T he commenter (1042

- 0300 / 1042

- 0348) suggested that facilities with less than 1

- in

- 1 million cancer risk should be exempt from the chromium limits in the rule.

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Response : Regarding the comment that the existing risk does not warrant imposing the chromium em ission limit in addition to the PM limit, the EPA disagrees with the commenter. In our November 2011 proposal, we performed an auxiliary risk characterization analysis to assess the potential maximum individual lifetime cancer risks in the event that all w ool fiberglass facilities switch to high

- chromium refractory. We assumed that chromium emissions for facilities would be the same as CertainTeed’s annual emission of 420 pounds of hexavalent chromium per furnace. The results of the auxiliary analysis indic ated that emissions from 14 facilities could lead to maximum individual cancer risks greater than 100

- in

- 1

- million, with the highest emitting facility posing a potential MIR of 900

- in

- 1

- million. See 76 FR 72800

- 72 801 for a complete discussion of the risk a ssessment of the Wool Fiberglass Manufacturing source category. As also explained in our November 2014 proposal, we limited the chromium emissions from gas

- fired glass

- melting furnaces in response to similar comments. (79 FR 68024). This is because an MIR of 3

- in

- 1 million was attributable to hexavalent chromium from a gas

- fired glass

- melting furnace located at the facility that contributes the highest risk in this source category

. Regarding the comment that facilities with less than 1

- in

- 1 million cancer risk should be exempt from the chromium limits in the rule, we have no such authority under CAA section 112(f)(2). According to CAA section 112(f)(2)(A), if the MACT standards for HAP “classified as a known, probable, or possible human carcinogen do not re duce lifetime excess cancer risks to the individual most exposed to emissions from a source in the category or subcategory to less than one in one million,” the EPA must promulgate residual risk standards for the source category (or subcategory), as necess ary to provide an ample margin of safety to protect public health. The final chromium emissions limit appl ies to affected sources in the source category (i.e., gas

- fired glass

- melting furnaces) . If such sources have chromium emissions that fall below this emission limit, as many gas

- fired furnaces currently do, they are in compliance with the chromium limits, and their only impacts are the cost of conducting emissions tests to demonstrate compliance with the limit. As discussed in the memorandum “Chromium E missions and Furnace Age” (EPA

- HQ

- OAR

- 2010

- 1042

- 0332), available chromium emissions testing data and information indicate that emissions of chromium increase with furnace age; therefore a furnace whose chromium emissions tested at levels well below the lim its (with risk below 1

- in

- 1 million) during a particular year’s compliance test, may test at or above the limit in subsequent years due to furnace degradation. Requiring emission limits for all gas

- fired sources prevents all such furnaces from emitting chr omium at the high levels similar to the gas

- fired glass

- melting furnace with the highest emissions level tested (approximately 500 pounds per year of hexavalent chromium) and presenting a much higher risk.

The EPA has limited the scope of applicability of the chromium limit to only gas

- fired glass

- melting furnaces because electric

- only glass

- melting furnaces do not have the potential to emit elevated emissions of hexavalent chromium due to fundamental design, temperature, and fuel differences. As a result, electric glass

- melting furnaces at wool fiberglass manufacturing facilities are subject to a PM limit, but not a chromium limit.

25. Comment: One commenter (1041

- 0081) contended that EPA did not set residual risk standards for either source category that pro vide the requisite AMOS to protect public health, pursuant to CAA section 112(f)(2). For the Wool Fiberglass Manufacturing source category, the commenter supported the EPA’s recognition that a residual risk standard is needed, but urged the EPA to finalize stronger residual risk standards. The commenter noted that EPA’s

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proposed chromium limit ( 6.0E

- 05 lbs per ton of glass pulled) was expected to decrease the cancer risk (MIR) from 40

- in

- 1 million to 20

- in

- 1 million, based on actual emissions. According
to the commenter, the standards are not expected to reduce the acute or chronic noncancer health risks at all. According to the commenter, the requirement for an AMOS is designed to protect public health in light of scientific uncertainty regarding what preci se level of risk is safe.

According to the commenter, the statutory term “ample” means more than adequate, implying a generous, health

- protective approach to set a margin of safety that is copious and abundant, and the commenter believed that the EPA did not take such an approach, rendering the phrase “ample margin of safety to protect public health” superfluous and in violation of CAA section 112(f)(2). The commenter argued that EPA does not discuss how the health risk information shows that an AMOS is provided by the proposed rule or what constitutes that ample margin. The commenter argued that EPA also does not explain how it follows that, just because EPA has been unable to identify what it deems to be less expensive options, the margin of safety is ample.

The commenter noted th at EPA interpreted CAA section 112(f)(2) as requiring the agency to provide maximum feasible protection against risks to health from HAP, both by protecting the greatest number of persons possible from an individual lifetime risk level no higher than 1

- in

- 1 million and by protecting the most

- exposed person from a cancer risk of 100

- in

- 1 million. The commenter contended that EPA failed to satisfy even this standard, which the commenter characterized as not protective enough.

The commenter urged EPA to consid er and require additional emission reductions at the ample margin stage to ensure that there is a truly ample amount of protection for affected communities’ health, particularly for children.

Response: As stated in the Benzene NESHAP (54 FR 38044, 38061, S eptember 14, 1989), in determining the need for residual risk standards, we strive to limit to no higher than approximately 1

- in

- 10 thousand (100

- in

- 1 million) the estimated cancer risk that a person living near a plant would have if he or she were exposed to the maximum pollutant concentrations for 70 years and, in the AMOS decision, to protect the greatest number of persons possible to an individual lifetime risk level of no higher than approximately 1

- in

- 1 million. However, in determining whether to requ ire additional standards under CAA section 112(f), these levels are not considered rigid lines, and we weigh the cancer risk values with a series of other health measures. In the AMOS determination we also consider costs, energy, safety and other relevant factors for the available control options. We continue to believe that CAA section 112(f)(2) does not impose a mandatory obligation to reduce maximum lifetime cancer risk to below 1

- in

- 1 million. As explained in the November 2011 proposal, we believe CAA s ection 112(f)(2) expressly preserves our use of the two

- step process for developing standards to address any residual risk in our interpretation set out in the Benzene NESHAP. Section 112(f)(2)(B) of the CAA preserves this interpretation and the U.S. Court of Appeals for the District of Columbia Circuit has upheld as reasonable the EPA’s interpretation that CAA subsection 112(f)(2) incorporates the approach established in the Benzene NESHAP. NRDC v. EPA , 529 F.3d 1077, 1083 (D.C. Cir. 2008) (“[S]ubsection 1 12(f)(2)(B) expressly incorporates the EPA’s interpretation of the Clean Air Act from the Benzene standard, complete with a citation to the

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Federal Register.”); see also “ A Legislative History of the Clean Air Act Amendments of 1990, ” vol ume 1, p. 877 (Sen ate debate on Conference Report).

We agree with the commenter that we did not show the options for reducing HAP emissions that were explored to reduce risk from these source categories in our 2011 and 2013 proposals. As previously explained in response t o comments like this, we provided the analyses in the docket for our 2014 proposal and have subsequently updated them for the final rule (see the memoranda “Mineral Wool RTR Ample Margin of Safety (AMOS)

– Analysis and Proposed Controls” and “Wool Fibergla ss RTR Ample Margin of Safety (AMOS)

– Analysis and Proposed Controls.”)

In our AMOS analysis for mineral wool

, we evaluated several potential measures or options for reducing formaldehyde emissions from bonded lines, but no new technologies (beyond those technologies already in place) were found. A pollution prevention option (the use of non

- HAP binders) was consi dered, but we found that product (performance) specifications of mineral wool products made this option technically infeasible. In addition, we evaluated controls for the collection process on bonded lines and found that controls capable of handling the hi gh volume air flows characteristic of most collection processes would be cost prohibitive. The potential of re

- routing exhaust from the collection process through existing incineration or other control equipment was also considered. We found that existing facilities do not have equipment with sufficient capacity to handle the additional flow and pollutant loading of the collection chamber ; therefore

, this option would not be technically feasible (see Section 112(d)(6) Technology Review for Mineral Wool NESH AP , docket item EPA

- HQ

- OAR

- 2010

- 1041

- 0111). Therefore, considering cost and technical feasibility, no feasible options for increasing the ample margin of safety were identified for mineral wool production facilities.

In our AMOS analysis for wool fibergla ss , w e considered several process alternatives and control options for reducing chromium emissions from glass

- melting furnaces which are summarized in the AMOS memorandum

. Considering cost and technical feasibility, rebuilding
gas

- fired glass

- melting furna ces before degradation of the refractory causes elevated chromium emissions (i.e., reducing the operational life of the gas

- fired furnaces from 10 years to 7 years ) was identified as the most feasible option for increasing the ample margin of safety for wo ol fiberglass manufacturing facilities. Sources may choose to rebuild a high

- emitting furnace earlier than its projected end

- of

- campaign to meet the chromium emissions limit of 2.5E

- 04 pounds total chromium per ton of glass pulled for gas

- fired glass

- melti ng furnaces. Industry identified other chromium emission reduction measures that may also be used, but our analyses show that an earlier furnace rebuild is likely to be the most cost effective way to meet the chromium emission limit. We also looked for pot ential measures or options for reducing formaldehyde emissions from bonded lines and n o new technologies (beyond those technologies already in place) were found. We also evaluated the use of non

- HAP binders in the wool fiberglass manufacturing industry and found that most facilities have already phased out the use of formaldehyde on bonded lines

.

26. Comment: One commenter (1041

- 0081) asserted that, for both source categories, the EPA’s analysis is completely based on cost, and that the EPA may not lawfully con sider cost in the AMOS decision, without an express authorization to consider cost in that analysis. The

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commenter asserted that the Supreme Court precedent in Whitman v. Am. Trucking Ass’n , 531 U.S. 457, 467 (2001), bars the EPA from considering cost absent a clear textual commitment.

It was unclear to the commenter whether the EPA considered any other control options or methods to further reduce emissions other than the controls for which it deems cost to be negligible. The commenter argued that, even assuming if cost was a factor, the EPA may consider in an AMOS analysis, the commenter asserted that the EPA’s proposal does not provide any analysis of what is, by definition, the central question in the inquiry into the AMOS to protect public health. Th e commenter contended that the EPA’s analysis does not consider the ample margin in terms of health or what margin would provide ample protection, particularly for children.

The commenter conceded that the D.C. Circuit previously allowed the agency to co nsider cost in the HON decision, but asserted that the case was wrongly decided and that the EPA should not rely on it as justification to evade the statute. The commenter maintains that the statute prohibits the agency from considering cost in its AMOS an alysis.

Response: We disagree with the commenter that CAA section 112 prohibits us from considering cost when evaluating technologies for the AMOS decision. As explained in our November 2011 proposal, the first step in the process of evaluating residual r isk is the determination of acceptable risk. If risks are unacceptable, the EPA cannot consider cost in identifying the emissions standards necessary to bring risks to an acceptable level . The second step is the determination of whether standards must be f urther revised in order to provide an ample margin of safety to protect public health. The ample margin of safety is the level at which the standards must be set, unless an even more stringent standard is necessary to prevent, taking into consideration cos ts, energy, safety and other relevant factors, an adverse environmental effect. As the commenter has correctly pointed out, case law precedence in the HON decision specifically allows us to consider cost impacts, and we did that for the risk drivers in the se source categories. However, we agree with the commenter that we should have explained our analysis of the ample margin of safety more completely in our 2011 and 2013 proposals . The details of this analysis can be found in the revised and updated risk as sessment report entitled, “ Residual Risk Assessment for the Mineral Wool Production and Wool Fiberglass Manufacturing Source Categories in Support of the June 2015 Final Rule ” found in the docket for this rulemaking.

27. Comment: One commenter (1041

- 0081) con tended that because the proposed wool fiberglass chromium limit is a production

- based limit, rather than a health

- based limit, it does not identify what amount of total chromium reduction is needed to provide an AMOS. Rather than set a limit measured only in terms of production, the commenter argued that EPA should set a total chromium limit to achieve an AMOS.

Response: Regarding the production

- based chromium emission limit in the wool fiberglass rule, while the emission limits are expressed in terms of po unds of pollutant per ton of product manufactured, this is a metric that lends itself to direct comparison with permit limits. Additionally, the total annual emissions of any of the regulated pollutants for these industries may be calculated using the emis sion limits and site

- specific production rate as follows:

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Production rate (ton/yr) x Emission limit (lb/ton) = Annual Emissions (lb chromium compounds), and Emissions (lb/yr)/2000 lb/ton = Annual Emissions (tons all other regulated pollutants).

Further, we did consider what the total chromium emissions would be for each facility, and we revisited the risk assessment based on post

- RTR compliance for each plant (76 FR 72802, November 25, 2011). For d etails on this reassessment of the risk, see the document entitled Risk Assessment for the Mineral Wool Production and Wool Fiberglass Manufacturing Source Categories in Support of the June 2015 Final Rule found in the docket for this rulemaking.

28. Comment: One commenter (1042

- 0121) noted that the proposed rule for the wool fiberglass manufacturing source category allows a cancer risk greater than 1

- in

- 1 million and a higher chronic non

- cancer risk twice EPA’s safety threshold

. Another commenter (1041

- 0081) stated that the EPA recognized the need for the wool fiberg lass manufacturing source category to reduce health risk due to chromium, but did not explain why it is only requiring a standard that would reduce cancer risk by 20

- in

- 1 million, and is still allowing emissions that will cause an MIR of 20 times the statu tory goal (1

- in

- 1 million based on allowable emissions). The commenter urged the EPA to set an absolute pollutant limit as measured in lbs or lbs per hour on chromium, not just a production

- based limit and that it is possible for the EPA to set an absolute limit in addition to a production

- based limit as evidenced by the proposed limit for startup and shutdown.

The commenter noted that the EPA does not consider or propose any standard to reduce acute or chronic non

- cancer risk for the wool fiberglass manuf acturing source category , even though the acute health risk is 30 times the EPA’s safety threshold. According to the commenter, in the 2011 proposal, the EPA appears to be relying on the industry statement that the industry “has converted or . . . announce d plans to convert to non

- phenol formaldehyde binders.” The commenter asserted that the agency cannot base the current rule on an industry group’s stated future plans and that relying on industry’s stated plans is an unlawful evasion of the EPA’s legal dut y.
The commenter supported the EPA’s proposed determination to promulgate a chromium limit but asserted that the EPA should finalize more stringent emission limits than it has proposed for the Wool Fiberglass Manufacturing source category and should stren gthen the proposed limits to achieve a cancer risk below 1

- in

- 1 million (the statutory goal), a chronic non

cancer risk below 0.2, and an acute health risk below 0.2 (per the EPA’s memorandum, Residual Risk Program: Selection of Hazard Index Limits (dated Oct. 4, 2002), EPA

- HQ

- OAR

- 2003

- 0048

- 0203), a multipathway risk below 1, and a cumulative burden that ensures an ample margin of safety from the combined health risks to this community.

Response : Setting an absolute pollutant emission limit, as suggested by the commenter, is not practical in this situation. Since risk is a function of emission rate, release height, meteorology and proximity to populations, establishing such an absolute emissions limit would require either a plant

- specific emission limit for each facility based on that facility’s emissions and distance to the surrounding population, or identifying the one facility that is located closest to populations or sensitive receptors and de termining the maximum emissions rate for that

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facility and applying that rate to all facilities in the source category. In either case, the circumstances could change from year to year. Note that we generally do not draw bright lines (i.e., 1

- in

- 1 million MIR) of acceptability regarding cancer or non

- cancer risks from source category HAP emissions, and that it is always important to consider the specific uncertainties of the emissions and health effects information regarding the source category in question when deciding exactly what level of cancer and non

- cancer risk should be considered acceptable. In addition, the source category

- specific decision of what constitutes an acceptable level of risk should be a holistic one; that is, it should simultaneously c onsider all potential health impacts

-- chronic and acute, cancer and non

- cancer, and multipathway

-- along with their uncertainties, when determining the acceptable level of source category risk. Experience with source category rulemakings in the past tells u s that this means that drawing bright lines for such decision

making is impossible. The Benzene NESHAP decision framework of 1989 acknowledged this; in today‘s world, such flexibility is even more imperative, because new information relevant to the questio n of risk acceptability is being developed all the time, and the accuracy and uncertainty of each piece of information must be considered in a weight

- of

- evidence approach for each decision. This relevant body of information is growing fast (and it will con tinue to grow faster and faster), necessitating a flexible weight

- of

- evidence approach that acknowledges both complexity and uncertainty in the simplest and most transparent way possible. While this challenge is formidable, it is nonetheless the goal of th e EPA‘s RTR decision

- making, and it is the goal of the risk assessment to provide the information to support the decision

- making
process.
Regarding the comment that we are relying on an industry statement that the industry will be phasing out the use of PF binders and that we are evading our legal duty, we disagree with the
commenter. As discussed in section V.H of the preamble to the final rule, sources that use RS lines have been phasing out the use of PF binders , but, at the time we conducted the risk

as sessment, we did not know which lines and facilities were formaldehyde

- free. We therefore, included the available actual emissions from the RS bonded lines in the risk assessment we conducted for this source category

. Regarding the proposed formaldehyde, m ethanol, and phenol limits for RS lines, as noted in the preamble to the final rule, we are not establishing MACT standards for RS manufacturing lines at wool fiberglass manufacturing facilities in this final action. We have issued an ICR under CAA section 114 to collect updated emissions and process information from the industry and we will analyze the ICR data and evaluate MACT limits for RS lines at wool fiberglass manufacturing facilities at a future date. With regard to FA lines, we have explained that the EPA proposed to discontinue the use of formaldehyde as a surrogate for phenol and methanol. 76 FR 72788, 72791; 72796. The EPA may attribute characteristics of a subclass of substances to an entire class of substances if doing so is scientifically rea sonable. Dithiocarbamate Task Force v. EPA , 98 F.3d 1394, 1399 (D.C. Cir. 1996). As also explained in the preamble to the final rule, we are establishing emission limits for formaldehyde, phenol and methanol at the MACT floor level of control because the e xisting standard for formaldehyde was calculated incorrectly

. With regard to the emissions limit for chromium compounds, we evaluated the public comments received in response to the 2014 supplemental proposal and the available emissions data for gas

- fired glass

- melting furnaces that had been rebuilt, which is the most demonstrated technology for reducing chromium emissions. We received comment that, in one case, newly

rebuilt furnaces may not be able to demonstrate compliance with the proposed emission lim it of

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6.0E

- 05 pounds of total chromium per ton of glass, based on one specific example from the 2012 test data in which a 1

- year old furnace emitted 2.5E

- 04 pounds of chromium per ton of glass. We reevaluated the technology, and based on the data available , newly

- rebuilt gas

- fired glass

melting furnaces operate below an emissions level of 2.5E

- 04 pounds per ton of glass pulled. We conducted an assessment of the risk attributable to all HAP for each facility and determined that increasing the chromium compou nd emission limit from 6.0E

- 05 to 2.5E

- 04 pounds total chromium per ton of glass pulled has a minimal effect on the post

- RTR risks because these risks are largely driven by formaldehyde emissions. Specifically, at the chromium compounds emission limit of 2. 5E

- 04 pounds total chromium per ton of glass pulled, the MIR due to only chromium emissions for the source category is 3

- in

- 1 million; whereas, the MIR due to only formaldehyde post

- RTR emissions for the source category is 60

- in

- 1 million. As noted above, these post

- RTR risks were determined to be acceptable. Therefore, a more stringent emissions limit for chromium compounds would not significantly reduce the risks

.
We note that

, based on information provided by the industry, the wool fiberglass industry has phased out the use of PF binders on 95 percent of the RS lines. However, this phase out is not reflected in the actual emissions data available to us. Therefore, we believe the risks from wool fiberglass manufacturing from actual emissions are lower than our estimated MIR of 60

- in

1 million for formaldehyde emissions for major sources

. The emissions and risks associated with formaldehyde emissions will be further investigated ba sed on industry responses to the CAA section 114 ICR that we have issued as mentioned in the previous paragraph.

Further, we note that the source for the commenter’s statement that default limits for HI should or must be established at 0.2 rests on an internal EPA staff memorandum (from 2002) that was never adopted as agency policy (and never reviewed by the public or by any peer review body) and consequently carries no precedential weight.

29. Comment: According to one commenter (1041

- 0081), the EPA also m ust consider enforceability when setting standards, and the commenter urged EPA to ensure that it sets a limit that will allow concerned local residents to assess compliance.

Response : Regarding the public’s ability to assess compliance with the standard, Enforcement and Compliance History Online (ECHO) is a Web

- based tool that provides public access to compliance and enforcement information for approximately 800,000 EPA

- regulated facilities. ECHO allows users to find permit, inspection, violation, enforce ment action, and penalty information covering the past three years. The site includes facilities regulated as CAA stationary sources, Clean Water Act (CWA) direct dischargers, and Resource Conservation and Recovery Act hazardous waste generators/handlers. The data in ECHO are updated monthly.

Review of the detailed facility report in ECHO lists whether a stack test was conducted and whether the source passed or failed their compliance demonstration.

Regarding the enforceability of the standard, the EPA co nsidered this aspect in both the November 25, 2011 proposed rule and in the April 15, 2013 supplemental proposal, and the Office of Enforcement and Compliance Assurance (OECA) was involved in the development of both proposals and the final rule so that the resulting rule could be enforced and compliance with the rule determined. To further aid in compliance , the final rule includes requirement s (further

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discussed in section VI. A of the preamble to the final rule) for facilities to establish the percentage o f cullet used in the materials mix fed to the furnace during the initial performance test and to maintain the percentage of cullet at or below th at established level

.

30. Comment: One commenter (1041

- 0081) stated that the EPA did not provide a determination of the environmental effects and that EPA cannot assume there is no potential for environmental effects based on the health assessment.

According to the commenter, the EPA did not consider or address whether a more stringent limit than the existing MACT is r equired to protect the environment. The commenter noted that the EPA proposed environmental risks were deemed negligible, and evaluated the potential for significant ecological exposures to non PB

- HAP. The commenter noted that the EPA based the environment al determination on the human health assessment.

The commenter observed that under CAA section 112(f)(2), the EPA is required to determine whether to set a standard to prevent an adverse environmental effect. According to the commenter, adverse environment al effect is defined as any significant and widespread adverse effect, which may reasonably be anticipated to wildlife, aquatic life, or other natural resources, including adverse impacts on populations of endangered or threatened species or significant de gradation of environmental quality over broad areas. As the D.C. Circuit has explained (244 Sierra Club v. EPA , 353 F.3d 976, 992 (D.C. Circuit 2004)), the commenter asserted that the residual risk review is the proper time for the EPA to consider these ef fects, including the need to engage in Endangered Species Act consultation under 16 U.S.C. §536.

According to the commenter, the EPA may not rely on its human health risk assessment alone to satisfy its environmental duty under CAA section 112(f)(2). Alth ough the EPA states that the reference doses it is using are more protective than the EPA believes is necessary to protect laboratory animals such as rodents, the commenter asserted that EPA gives no basis for why this is a sufficient way to prevent an adv erse environmental effect for more sensitive wildlife or other environmental receptors. The commenter noted that the EPA also says nothing at all about ESA consultation, which provides further evidence that it has not considered or addressed its duty to pr event adverse environmental effects, as recognized by the D.C. Circuit.

The commenter asserted that the SAB has stated: “The assumption that ecological receptors will be protected if human health is protected is incorrect.” In addition to inhalation risk f or wildlife and air impacts to plants, the commenter observed that chemicals that are persistent in the environment or bioaccumulative in living tissue will remain or increase over time, particularly in areas of high emissions. Accordingly, the commenter s tated that any additional exposure from current activities would thus be added to a background that is likely unsafe already for wildlife and other environmental resources. The commenter contended that the EPA should perform an appropriate ecological asses sment.

The commenter argued that the EPA should perform an ecological risk assessment for these source categories, and not simply rely only on the human health assessment. According to the commenter, the EPA neither carried out the required ecological risk assessment nor presented a reasoned explanation supported by science in the record.

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Response: We agree with the commenter that we did not evaluate environmental impacts independent of our human health assessment in either our November 25, 2011 or our Apri l 15, 2013 proposals. We also agree with the commenter that the approach used to evaluate environmental impacts in our 2011 and 2013 proposals did not address SAB’s concerns that “The assumption that ecological receptors will be protected if human health i s protected is incorrect.” To address these issues, we developed the environmental screening methodology that is briefly described below. This environmental screen was used to screen for environmental impacts in our 2014 proposal (79 FR 68016

- 68017) and th e final rule

. The environmental screen focuses on the following seven environmental HAP:

• Five persistent bioaccumulative HAP (PB

- HAP)

– cadmium, dioxins/furans, polycyclic organic matter (POM), mercury (both inorganic mercury and methyl mercury) and lead

.

• Two acid gases

- HCl, and HF.

In the environmental risk screen we evaluate the following four exposure media: terrestrial soils, surface water bodies, fish consumed by wildlife, and air. Within these four exposure media, we evaluate nine Generic Ecologi cal Assessment Endpoints (GEAEs). The GEAEs reflect the overall “health” of aquatic and terrestrial ecosystems and any important biota or community types that could b e exposed in those ecosystems. For persistent and bioaccumulative (PB) HAP, the generic se t of receptors include s both community

- level and population

- level endpoints; for acid gases, the receptors are terrestrial plant communities. Selection of species for the population

- level assessments for PB

- HAP was based on those organisms that are likely to be the most highly exposed due to bioaccumulation of the PB

- HAP through aquatic and terrestrial food chains.

For each HAP evaluated

, we identified the available ecological benchmarks for each of the GEAEs. An ecological benchmark represents a concentra tion of HAP (e.g., 0.77 μ g of HAP per liter of water) that has been linked to a particular environmental effect l evel through scientific study. Where possible, we identified existing ecological benchmarks for each ecological assessment endpoint at each of the following effect levels: Probable effect levels (PEL), Lowest

- observed

- adverse

- effect level (LOAEL), and No

- observed

- adverse

- effect levels (NOA EL). The benchmarks used in the environmental risk screen are shown in the Appendix to the final risk assessm ent document that is available in the docket.

For cadmium, mercury, PAHs, and dioxins/furans, the environmental screening analysis consists of two tiers. In Tier 1 of the screening analysis , HAP concentrations are modeled using facility specific HAP emissi ons at a hypothetical facility and using worst

- case meteorology. The hypothetical facility includes a conceptual model for the environment surrounding the facility

, including a conceptual lake. The Tier 1 modeling parameters are designed to encompass worst

case conditions to provide conservat ively high HAP concentrations. For those facilities that exceed the no

- effect level in the Tier 1 screening analysis, we conduct a Tier II screening analysis that estimates the emissions concentrations based on the actu al meteorology near the facilities and the actual locations of lakes in the vicinity of the facilities.

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Potential adverse environmental effects on terrestrial plant communities caused by acid gas emissions are screened in a single

- tier. The acid gas scre en utilizes HF and HCl concentrations that are modeled based on actual facility emissions and meteorology. W e compare these modeled concentrations to conservative lowest observable effect level (LOEL) ecological benchmarks in order to evaluate the p otentia l phytotoxicity and reduced productivity of plants due to chronic exposure to acid gases.

Of the seven pollutants included in the environmental risk screen, the facilities subject to this rulemaking emit lead, mercury (elemental and divalent), cadmium, HF and HCl . In the Tier I screening analysis for PB

– HAP other than lead (which was evaluated differently, as noted in the reference above), none of the individual modeled concentrations for any facility in the source categories exceed any of the ecological be nchmarks (either the LOAEL or NOAEL) for mercury or cadmium. Therefore, we did not conduct a Tier II screening assessment. For lead, we did not estimate any exceedances of the secondary lead NAAQS. For HC l and HF, the average modeled concentration around e ach facility (i.e., the average concentration of all off

- site data points in the modeling domain) did not exceed any ecological benchmarks (either the LOAEL or NOAEL). In addition, each individual modeled concentration of HF and HCl (i.e., each off

- site da ta point in the modeling domain) was below the ecological benchmarks for all facilities.

Because our environmental risk screen does not indicate an environmental effect from this source category, we disagree with the commenter’s statement that the EPA must engage in consultations (e.g., with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service) under 16 U.S.C. 1536(a)(2)

.

31. Comment: Three commenters (1042

- 0115f, 1042

- 0115k, and 1042

- 0126) questioned the validity of the emissions testing related to CertainTeed’s K2 furnace. One commenter (1042

- 0126) argued that EPA’s concer n over chromium emissions are overstated because they are based on a single test conducted in 2010 which the commenter characterized as erroneous. The commenter stated that the furnace was retested in 2011 and the resulting hexavalent chromium emission rat es were far less than the rates determined from the November 2010 test. The commenter estimated a linear relationship between risk and emission rate would result in a MIR of less than 10

- in

- 1

- million which is a risk factor generally accepted by EPA as bein g within a reasonable range.

One commenter (1042

- 0115f) stated that subsequent testing of the same furnace showed much lower emissions of hexavalent chromium. The commenter stated that EPA did the right thing by initiating direct monitoring of the air in G arland Park just south of the plant.

One commenter (1042

- 0115k) requested further clarification on the stack testing done at CertainTeed, specifically whether the testing conducted by CertainTeed in November 2010 was of the same merit as that conducted i n September of 2011; whether EPA considered both tests valid; and whether EPA can explain any differences between the two tests and operations at the company being tested.

Response: In response to the chromium testing at one facility exhibiting the highest hexavalent chrom ium emissions, EPA reviewed three tests at that facility: two tests on the K2 furnace and one test on the K1 furnace. The test on the K1 furnace and the first test conducted on

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the K2 furnace were done correctly and emissions were correctly calculated according to the test report submitted by the company. We also note that the company did not assert that an error was made in the K2 testing when we contacted them to d iscuss the results in April 2011. To the contrary, the company knew it had high emissions of chromium; that these emissions were attributed to the type of furnace, its production rate and operating temperatures; and the type of refractory used to construct the furnace, but that they did not realize that most of the chromium emitted was in the hexavalent state. The company also noted that it inspected the electrostatic precipitator in place on the K2 kiln and confirmed that it was working properly.

The compa ny retested the K2 furnace using a different test contractor in October 2011 and submitted a second source test for it to EPA. We completed a thorough review of the source test report submitted by the company, and conclude the following:

1. The results report ed for hexavalent chromium in the report submitted by the company are in error, and are reported low by at least one order of magnitude. This error is due to the test contractor referencing the wrong lab data in calculating the hexavalent chromium emission s. The reported hexavalent chromium emissions are based on reported values from the nitric acid sample analysis from method 0061, while these calculations should have been derived from the potassium hydroxide samples analyzed and reported by the lab. Our c alculations show the hexavalent chromium average of the three test runs to be in the neighborhood of 75 lb/yr of hexavalent chromium emissions, rather than the reported result of approximately 7 lbs/yr.

2. Furthermore, the results reported for hexavalent chr omium were blank

- corrected based on the wrong lab data as well. Blank values from M ethod 29 nitric reagent analysis were used, when the appropriate blank values should have been taken from the potassium hydroxide blank analysis instead.

3. While the Test Prot ocol for this sampling stated that the testing company would send the method 0061 filter to the lab for total chrom ium analysis, this was not done (at least there is no lab data to support this) and so the total chrom ium result from the M ethod 29 multi

- met als test is the total chrom ium number presented in the report. Method 29 calculations and lab data are appropriate, save the minor concern with barium spike recovery listed in the lab’s narrative, and some background zinc present in the method blank, and w e expect the total chromium measured by M ethod 29 to be an accurate assessment of the emissions during the testing.

4. We found no deficiencies in the laboratory analysis, other than the omission of the method 0061 filter analysis; though it appears this was not submitted to them for analysis.

5. Flow rate measurement indicates very low flow, with delta

- p values recorded below the method sensitivity level of 0.05” H 2 O column. There are delta

- P data points that show three significant figures which indicate the us e of a gauge other than an inclined manometer (the test method standard) however there is no documentation in the test report to substantiate this. While this is a minor deviation from the method, it is not likely to have a significant impact on the result and indicates an effort on the part of the tester to improve their data quality above the method minimum.

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a. The flow rate change (less than 40 percent) in the October testing indicates that the source was making process changes that would lower their chrom ium emissions for this second round of testing (versus the 2010 test results).

b. If the source conducted the second tests with the same flow rate as the first set of tests they would have been emitting about 125 lb/yr of hexavalent chromium. This is about 2 5 percent of the total measured during the first testing in 2010, so we conclude the source is likely to have made other process changes in an effort to minimize the chromium emissions. Slowing the flow rate through the ESP particulate control device is on e way to improve the collection efficiency of the device and lower metals emissions. This is consistent with the results as we calculate them, but may not be solely responsible for the lower emissions result of this data set.

c. Lower CO 2 emissions and lower stack temperature noted in the October tests generally point to an increase in dilution air for this testing; however with a lower flow rate measurement this is contraindicated. If the source were able to find a way to keep the melt at the needed temperat ure and use less fuel, this would seem to reconcile well with the results measured by the October testing.

6. Sample temperature on arrival at the laboratory was noted at 19.6°C which is higher than the lab method requirement of 4°C to 6°C. The impact of this is likely to be minimal, in the EPA’s estimation, as this requirement is meant to safeguard the stability of hexavalent chromium in the solution. The risk of elevated sample temperature prior to analysis is that it may drive the fraction of hexavalent to trivalent chromium in the sample toward a trivalent bias. However, after calculating the emissions based on the appropriate lab data we find that over 90 percent of the chromium emissions were measured as hexavalent, so we conclude that any impact this had on the stability of hexavalent chromium in the reagent solution prior to analysis is likely to be of minimal impact to the result.

7. The pH of the #1 impinger solution during test run 1 was listed below method specification at the conclusion of the test run . The solution pH is reported as being 8.5, while the test method (SW

- 846 method 0061, section 5.2.2) stipulates that this value should be “...above 8.5 after sampling.” It is our understanding from conversation with the testing officials at EPA Region 7 tha t there was some difficulty reading the pH indicator in the field following this run and that it was difficult to determine if the value was 8, 8.5, or 9, and that 8.5 was chosen as a compromise with the understanding of those present that it met the metho d minimum. While this reported value technically does not meet the method minimum, we find that the data is likely to be representative of emissions based on the following:

a. Test run 1 results are neither the high nor low of this sample set, but the middle of the three samples. Emissions averages calculated with or without this number in the set do not markedly change the calculated emissions when the appropriate hexavalent chromium data are used.

b. T he analytical portion of this test method, EPA method 7199, states that good sample stability is achieved when the pH is kept at 7 or higher (above 6.5). This

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indicates to us that a pH of 8.5 is not likely to have had a negative impact on the measured hexavalent chromium emissions.

c. A sample compromised by lower pH would present itself in a shift of the result away from hexavalent chromium toward trivalent chromium emissions, with the expectation that the ratio of hexavalent to trivalent would be lower. Test run 1 still shows hexavalent chromium emissions to be above 90 percent of the sample catch, both consistent with the other test data and indicative of minimal interference from any pH driven chemical changes in the matrix of the solution. In summary, we concluded that the 2011 testing was conducted properly; howev er , because the calculations done during the reporting phase were in correct, the reported numbers

were also incorrect and low. The corrected values presented by the test contractor were appropriate (and much higher than their original report). There remain s the issue of discarded filters that were required under the method to be analyzed for hexavalent chromium; this step was not conducted and contributed to the low measured hexavalent emissions. While there appears to be no further reasons to discard the 2 010 data (after corrections and assumptions of the level of hexavalent chromium that the discarded filter may have contained), the corrected 2011 report confirms emissions of the same order of magnitude, though slightly lower than the 2010 testing. This lo wer value may be attributed to the discarded filter. Subsequently, we issued

a CAA section 114 ICR in December 2012, requesting test data on total chromium compounds emissions from all glass

- melting furnaces and we were able to confirm our view of chromium emissions from this source category in our April 2013 proposal

.

32. Comment: One c ommenter ( 1042

- 0115 ) opined that the EPA had concluded that the health risks from this category are unacceptable and the commenter argued that the proposed new standard for chromium does not provide an ample margin of safety. The commenter stated that the higher temperature of oxyfuel design is part of the problem and this is a special concern in Kansas City, Kansas. The commenter believe d it is likely that citizens near the plant have been exposed to higher hexavalent chromium emissions than was assumed in the health risk assessment conducted by the EPA. The commenter noted that even the EPA's limited analysis showed that Owens Corning plant adds about 25 percent to the r isk calculated from the CertainTeed operation.

Response: Contrary to the statement made by the commenter, the EPA did not determine that risks from the Wool Fiberglass Manufacturing source category were unacceptable at proposal. Rather, we explained that w e had conducted a risk assessment that provided estimates of the MIR posed by the allowable and actual HAP emissions from this source category, the distribution of cancer risks within the exposed populations, cancer incidence, HI for chronic exposures to H AP with noncancer health effects, and HQ for acute exposures to HAP with non

cancer health effects. Specifically, we found that formaldehyde is the primary HAP driving the risks from this source category. The greatest MIR resulted from MACT

- allowable forma ldehyde emissions from one facility in the source category and was assessed at 40

- in

- 1 million. Additional analyses showed that the cancer incidence and number of people with cancer risk over 1

- in

- 1 million were low. We found that the residual risks to pub lic health are acceptable. We also proposed emission limits for total chromium compounds that would achieve an ample margin of safety to protect public health and prevent adverse environmental effects. At proposal, we also performed an auxiliary risk chara cterization analysis to assess the potential maximum

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individual lifetime cancer risks in the event that all Wool Fiberglass facilities switch to high chromium refractory brick. We assumed that chromium emissions for facilities would be the same as CertainT eed’s annual emission of 420 pounds of hexavalent chromium per furnace. The results of the auxiliary analysis indicated that emissions from 14 facilities could lead to maximum individual cancer risks greater than 100

- in

- 1

- million, with the highest emitting facility posing a potential maximum individual risk of 900

- in

- 1

- million. See 76 FR 72800

- 801 for a complete discussion of the risk assessment of the Wool Fiberglass Manufacturing source category

. Regarding the secondary risk driver, hexavalent chromium, we reevaluated the performance associated with rebuilding gas

- fired glass

- melting furnaces, based on public comments and the available emissions data, and determined that newly

- rebuilt furnaces operate below an emissions level of 2.5E

- 04 pounds per ton of glass pulled. The final standard for chromium reflects this level of emissions and the cancer risk from hexavalent chromium after implementation of the final standards is no higher than 3

- in

- 1 million . The results of the risk assessment are presented in mo re detail in the final residual risk memorandum titled “Residual Risk Assessment for the Mineral Wool Production and Wool Fiberglass Manufacturing Source Categories in Support of the June 2015 Final Rule”, which can be found in Docket ID No. EPA

HQ

- OAR

- 201 0

- 1042.

Additionally, we have further evaluated the cost, emissions reductions, energy implications and cost

- effectiveness of both the PM and total chromium compounds emission limits being promulgated in this final rule and have determined that they are co st effective, technically feasible and will provide an ample margin of safety to protect public health and prevent adverse environmental effects. We have further determined that there have been developments in practices, processes or control technologies s ince promulgation of the MACT standards that warrant revisions to the MACT standard. Therefore, to satisfy CAA sections 112(d)(6) and 112(f)(2) of the CAA, we are promulgating a limit of 2.5E

- 04 pounds of chromium compounds per ton of glass pulled for both existing and new furnaces and lowering the MACT standard for PM from the current 0.50 lb PM per ton of glass pulled to 0.33 lb of PM per ton of glass pulled for both existing and new furnaces.

33. Comment: One commenter (1042

- 0115f) suggested that air monito ring around Kansas City, Kansas, was conducted for the residual risk assessment, and added that such monitoring should be conducted for other RTR rules being proposed by the agency.

The commenter also stated that the health risk assessment is not conserva tive for other reasons as well. The commenter noted that the EPA's model did not consider risks from other nearby sources of industrial pollution that included a medical waste incinerator, the General Motors assembly plant and the Quindaro Coal Fire Power Station. The commenter observed that the area is also home to large numbers of diesel trucks and trains.

Another commenter (1042

- 0115k) stated that the EPA needs to rerun the risk models so that a full picture of the effects of the pollutants on the bluff s (Kansas City, Kansas) can be obtained.

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Response : We agree that ambient air monitoring, when available for specific HAP of concern, can be a useful tool for ground

- truthing emission estimates. In this particular case, EPA Region 7 conducted the monitoring to determine if the levels of hexavalent chromium from any local sources posed health concerns for local residents. In addition to emissions of hexavalent chromium from wool fiberglass furnaces, other sources of HAP in the area include a coal

- fired power plant, a medical waste incinerator, and a landfill. While the monitoring results were not conducted for the residual risk assessment of the wool fiberglass RTR, we note that the results of the ambient air monitoring gen erally agree with our risk assessment results for this source category.

Our approach here is consistent with the approach we took regarding this issue in the Hazardous Organic NESHAP (HON) RTR, which the court upheld in the face of claims that the EPA had not adequately considered background ( NRDC v. EPA , 529 F.3d 1077 (D.C. Cir. 2008)). Questions regarding risk from industrial sources other than those specifically addressed by this rulemaking may be addressed to Region 7 as a part of the larger stakeholde r meetings in which the Region may answer questions that go beyond the context of this rulemaking.

C. UPL Approach to Limited Datasets

34. Comment: One commenter (1042

- 0348) agreed with the EPA that an analysis of the uncertainty inherent in source test data is r equired, and agreed that the EPA’s proposed UPL methodology to addressing limited datasets (79 FR 68017, November 13, 2014), if correctly applied, is necessary and useful to account for the uncertainty associated with available emission data (e.g., due to the number of emission samples available and the number of samples that will be collected to assess compliance with the emission limit).

The commenter indicated, however, that they were not able to adequately review the EPA’s application of this UPL metho d because the EPA did not provide in the docket a detailed explanation of its application of the method, and, as a result, the EPA’s determinations were “far from clear or identifiable.” The commenter maintained that it was not possible to determine if the UPL methodology was consistently applied and what the rationale was for the EPA’s results (e.g., use of data below the detection limit from testing, properly skewing of data, data distribution fit, use of only relevant data). The commenter provided the ex ample that it was not clear if certain formaldehyde, phenol and methanol limits (e.g., those for the RS wool forming process) developed using the UPL method were based on data that were “clearly generated in accordance with the protocols that were gathered in accordance with the present MACT rule requirements.” Another commenter (1042

- 0347) stated that the EPA failed to provide adequate justification and factual support because the EPA’s limited datasets and UPL memoranda do not clearly explain EPA’s analys is.

One commenter (1042

- 0348) further pointed out that the UPL method for limited datasets was applied to every limit in the 2014 proposal except for chromium compounds, noting that application of the method to chromium data would yield a higher limit than proposed.

Response : We disagree with the commenters that we did not provide detailed explanations of the use of the UPL approach in support of the 2014 supplemental proposal. O ur use of the UPL and the approach followed to calculate the MACT floors is clearly explained in

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the following memorand a available in the dockets to this rulemaking: “Use of the Upper Prediction Limit for Calculating MACT Floors,” “Approach for Applying the Upper Prediction Limit to Limited Datasets,” “ Revised Technical Approach f or Mineral Wool MACT Floor Calculations,” and “ Revised Technical Approach for Wool Fiberglass MACT Floor Calculations.” The various memorandum detail our approach to evaluating which data sets require additional scrutiny and what steps we now use to ensure that limited data sets are appropriately evaluated.

With regard to the commenter’s observation that we did not apply the UPL methodology in establishing the emission limit for chromium compounds, the commenter is correct. T his limit is being finalized und er CAA section s 112(d)(6) and 112(f)(2) as an outcome of both our technology review and our AMOS analysis. Consequently, we did not calculate a MACT floor and, therefore, we did not use the UPL approach which is applied when establishing emission limits as part of the MACT floor analysis.

35. Comment : One commenter (1042

- 0347) opined that the EPA’s use of UPL is arbitrary and capricious, resulting in proposed MACT floors that do not reflect CAA section 112(d)(3) language: “the average emission limitation achie ved by the best performing 12 percent of the existing sources.” The commenter pointed out that the D.C. Circuit remanded under CAA section 7429(a)(2) the EPA’s use of the UPL method in NACWA v. EPA , 734 F.3d 1115, 1139

- 45 (D.C. Cir. 2013) for sewage sludge incinerators. The Court found that the EPA seemed to have interpreted “‘average emissions limitation achieved by the best performing 12 percent’ . . . [to] refer to the future average of a 3

- run test that the EPA predicts a source in the best

performing 1 2 percent will fall below with 99 percent confidence.” It then held that the EPA must provide clarification on two points:

Although EPA may be able to justify its novel interpretation that “average” means the average of a future 3

- run compliance test, one sentence in the Federal Register is not enough of a basis to uphold EPA’s new approach to incorporating variability against arbitrary and capricious review. Accordingly, on remand, we expect EPA to clarify how the upper prediction limit represents the “av erage emissions limitation achieved by the best performing 12 percent.” The Court also noted that the upper prediction limit produces an “apparently illogical result.” For example, EPA predicted a “higher MACT floor for an incinerator with raw test data ra nging from 0.31 to 2.26 than for a group of incinerators with raw test data ranging from 0.31 to 40.32 and a mean of 9.38.” The Court remanded on this issue as well, observing “[w]e are hesitant to rubber

- stamp EPA’s invocation of statistics without some e xplanation of the underlying principles or reasons why its formulas would produce an accurate result, particularly when the ‘facts found’

– the MACT floor datasets

– demonstrate flaws in the formula.” [footnotes omitted]

Response : The EPA first notes tha t the commenters reference a court decision that addressed MACT standards for a different source category, which are not at issue in this rulemaking. Second, the commenter did not assert that the methodology resulted in an “apparently illogical result” in this rulemaking (the apparently illogical result was where the calculated limit for the best performing unit was higher than the calculated limit for the best performing 12 percent of units), as the court pointed out in NACWA. Rather, the commenter
asserts that the methodology results in limits that are less stringent than they believe is required.

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Finally, the UPL methodology used to establish the MACT standards referenced in the comment (from the sewage sludge incinerators rule) was not the same UPL metho dology used to set the standards in the final action. We note that the “apparently illogical result” in the sewage sludge incinerators rule resulted from analysis of small datasets and the use of procedures that the EPA no longer follows. We included in th e docket a memorandum explaining how we adjusted the UPL methodology to a ddress situations in which the a gency must establish MACT standards with limited data. That memorandum, entitled Approach for Applying the Upper Predictive Limit to Limited Datasets ( Docket No. EPA

- HQ

- OAR

- 2010

- 0895

- 0178) (Limited Datasets Memorandum), provides an analysis of the use of the UPL for limited data sets and includes procedures to evaluate whether additional analyses beyond the use of the 99 percent UPL are needed. We also n ote that the “apparently illogical results” questioned by the court will no longer occur provided the procedures laid out in our UPL memorandum and limited data sets memorandum are followed. The EPA followed those procedures in this rulemaking. Therefore, this criticism of a prior rulemaking’s record is irrelevant to analyzing the record supporting the standards in this rulemaking. The commenter provides no analysis of the approach described in the limited data sets memorandum, but simply refers to a court decision addressing standards in a different rule that pre

- dated that approach. The limited data sets memorandum outlines procedures for the EPA to follow to ensure that the statistical approach results in limits that reflect the actual performance of the best performing unit or units. Three key changes to the EPA’s methodology that are outlined in the limited data sets memorandum are the establishment of a minimum size data set for statistical analyses (3 data points), the use of improved analytical tools for determining the data distribution (which is key in selecting the appropriate equation to perform the calculations), and the establishment of qualitative criteria for comparing unit performance in order to inform the selection of the best performing uni t.

36. Comment: One commenter (1042

- 0347) stated that the EPA’s claim that it has discretion to set standards using an UPL “is unlawful under the Act, per Chevron .” The commenter opined that the statute is clear, and EPA may not read ambiguity into the statute where it does not exist, nor ignore the use of the unambiguous term “average emission limitation.” The commenter further argued that CAA section 7412(d)(3) unambiguously requires that floors reflect the “average” emission level “achieved in practice” by t he best

- performing 12 percent of sources, and by using the 99

- percent confidence level for calculating the UPL (to reasonably assure that the calculated limit can be met at all times by the best

- performing source(s)) the EPA has proposed a floor that resul ts in a greater

- than

- average level of emissions being achieved in practice, which fails to protect communities surrounding the wool fiberglass and mineral wool sources and is unlawful, arbitrary, and capricious.

Response : We disagree. Section 112(d)(3) of the CAA requires the EPA to promulgate standards for major sources of HAP that are based on MACT performance. For existing sources, MACT standards must be at least as stringent as the average emission limitation achieved by the best performing 12 percent o f existing sources (for which the Administrator has emissions information) or the best performing 5 sources for source categories with less than 30 sources. For new sources, the MACT standards must be at least as stringent as the control level achieved in practice by the best controlled similar source. The reference to “sources” does not lead to the assumption the commenter makes that the best performing sources can only be the best

performing sources for the entire suite of regulated HAP. Instead, the lang uage can be reasonably interpreted as referring to the source as a whole or to performance as to a particular HAP.

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Similarly, the reference in the new source MACT floor provision to “emission control achieved by the best controlled similar source” can mean emission control as to a particular HAP or emission control achieved by a source as a whole. Also, CAA section 112(d) includes language such as “existing source,” “best performing,” and “achieved in practice” in referring to sources’ actual operations, bu t again the language does not address the question of whether, in assessing which sources perform best or are best controlled, emission levels should be evaluated either over time or in a single test result. Thus, the EPA has discretion to interpret the ph rase “average emission limitation achieved” by the best performing source or sources.

Further, the D.C. Circuit has held repeatedly that variability of best performing sources may be taken into account in establishing MACT floors. Id at 881

- 882. See also N ational Lime Ass’n v. EPA , 627 F.2d 416, 431 n.46, 443 (D.C. Cir. 1980). Therefore, we believe it is appropriate to consider statistical variability to ensure that regulated sources can meet the proposed limits at all times. Our analyses used the data from the best performing units to assess the actual performance of the units, considering the variability demonstrated by the data.

Regarding the assertion that by using the 99

- percent confidence level for calculating the UPL (to reasonably assure that the cal culated limit can be met at all times by the best

- performing source(s)) the EPA has proposed a floor that results in a greater

- than

- average level of emissions, the commenter misunderstands the meaning of the upper prediction limit. The UPL is in fact a ref lection of the relevant source or sources’ performance over time, and is calculated using the mathematical average emissions level of those sources based on stack test data, and then applying a factor that addresses the sources’ expected variation in emiss ions over time. As noted above, the D.C. Circuit has recognized that it is appropriate for the EPA to account for variability in establishing MACT standards. The data gathered through emission testing of sources in the ferroalloys source category are short

- term measurements rather than measures of what has been and can be achieved over time by the best performing source or sources. The EPA also disagrees that it lacks discretion to use the UPL in establishing MACT standards and as earlier stated that the te rm “average emission limitation” is unambiguous. In fact, the D.C. Circuit has long recognized the ambiguity in this term. See NACWA v. EPA , 734 F.3d at 1131 (noting that court has accorded Chevron deference to EPA’s interpretation of CAA sections 129 MACT floor requirement) and 112 (“the phrase ‘average emissions limitation achieved by the best performing 12 percent of units’ could be interpreted several different ways, with several different variations of what the MACT floor is supposed to represent”). Th e phrase “average emission limitation achieved by the best performing 12 percent of units” simply says nothing about the methodology the EPA should use to determine what the best performing sources are actually achieving. Absent a method for adjusting for variability like the UPL, a straight average of test runs for a unit does not capture the performance of a unit over time. As outlined in the UPL memorandum, we use short

- term test data to determine the actual performance of the best unit or units over tim e, based on the average of the emissions data.

37. Comment: One commenter (1042

- 0347) stated that use of the 99

- percent confidence level in the UPL approach results in proposed floors that are based on the EPA’s hypothetical emission levels that are much highe r than the level in the emissions data in the record, and that the EPA should collect better test data if the available data do not accurately reflect what sources have achieved. The commenter contended that the EPA may not collect test data and then sugge st that the data do not actually reflect source achievements.

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Response : The UPL is in fact a reflection of the relevant source or sources’ performance over time, and is calculated using the mathematical average emissions level of those sources based on sta ck test data, and then applying a factor that addresses the sources’ expected variation in emissions over time. While we acknowledge that the UPL can be calculated at different confidence levels, we selected the 99 percent level to provide reasonable assur ance that the limit can be met at all times by a source with emissions at the average level achieved by the best performing source or sources. The emissions data submitted by the industry to support this rulemaking were collected following the procedures s pecified in EPA reference test methods and under normal process conditions; however, the emissions data submitted to EPA represent emissions over the short term (e.g., a few hours per year). The purpose of the UPL is to predict the level of emissions that the sources upon which the floor is based are expected to meet over time, considering both the average emissions level achieved as well as emissions variability and the uncertainty that exists in the determination of emissions variability given the availab le, short

term data. As noted above, the D.C. Circuit has recognized that it is appropriate for the EPA to account for variability in establishing MACT standards. The data gathered through emission testing of sources in the ferroalloys source category are short

- term measurements rather than measures of what has been and can be achieved over time by the best performing source or sources. The EPA also disagrees that it lacks discretion to use the UPL in establishing MACT standards and as earlier stated that t he term “average emission limitation” is unambiguous. In fact, the D.C. Circuit has long recognized the ambiguity in this term. See NACWA v. EPA , 734 F.3d at 1131 (noting that court has accorded Chevron deference to the EPA’s interpretation of CAA section s 129 MACT floor requirement) and 112 (“the phrase ‘average emissions limitation achieved by the best performing 12 percent of units’ could be interpreted several different ways, with several different variations of what the MACT floor is supposed to repre sent”). The phrase “average emission limitation achieved by the best performing 12 percent of units” simply says nothing about the methodology EPA should use to determine what the best performing sources are actually achieving. Absent a method for adjustin g for variability like the UPL, a straight average of test runs for a unit does not capture the performance of a unit over time. As outlined in the UPL memorandum, we used short

- term test data to determine the actual performance of the best unit or units o ver time, based on the average of the emissions data.

Finally, the EPA is tasked with setting standards using available data and, while we agree that more data is desirable, the standards that we proposed are based on a considerable amount of data that, wh ile not perfect, provide sufficient information with which to develop standards that reasonably reflect the required levels of performance. (“EPA typically has wide latitude in determining the extent of data

- gathering necessary to solve a problem. We gener ally defer to an agency's decision to proceed on the basis of imperfect scientific information, rather than to invest the resources to conduct the perfect study.” Sierra Club v. EPA , 334 U.S. App. D.C. 421, 167 F.3d 658, 662 (D.C. Cir. 1999) (citation omit ted)). The EPA must rely on emission test methods that are available to the Agency and to sources. The task of s electing an appropriate test method is one for the technical expertise of the agency, and the approach we take to setting standards accounts for the accuracy of the emission test method. See NACWA at 1155. As described in the UPL memorandum, our standards reflect the average emission limitation achieved by the best source or sources as required under the statute.

38. Comment: One commenter (1042

- 0347) contended that the EPA violated CAA section 7412(d)(3) by failing to ensure that the average of emissions achie ved in practice by the

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best

- performing sources is reflected in the floors it proposes based on use of Representative Detection Limit values (RDL). The commenter opined that the EPA’s documentation regarding the RDL does not clearly identify which sources c ontained BDL data and when the 3xRDL approach was used to create floors; therefore, it is not possible to provide a meaningful comment without a clear explanation on this.

Response : We disagree with the commenter that the documentation regarding the use of the RDL approach (Revised Technical Approach for Wool Fiberglass MACT Floor Calculations) was unclear. However, because the data submitted by the industry were claimed as CBI, we were unable to present specific data values in the memorandum.

We note that the use of the RDL in establishing the emission limit for HCl is consistent with the approach approved by the court in NACWA v. EPA , 734 F.3d 1115, 1154

– 55. Specifically, the EPA calculated a numeric limit according to our standard UPL

- based procedure, and then compared that result to a value equal to 3 x RDL. The 3 x RDL value is a value that the EPA established as the lowest level of emissions that can be accurately measured using the required test method. Descriptions of the development of 3 x RDL val ues and the rationale that was upheld by the court are included in Docket Item No. EPA

- HQ

- OAR

- 2010

- 0895

- 0034. Our standard MACT methodology includes comparing each calculated limit to the 3 x RDL value in order to ensure that emissions at the level of the standard can be accurately measured. For the emission limit being questioned by the commenter, the 3 x RDL value was greater than the UPL

based value, and we therefore set the limit at the 3 x RDL value. In the court decision cited above, the court stated the following regarding this methodology:

“We agree with EPA that its method of incorporating nondetect data is reasonable, and not arbitrary or capricious. We do not expect EPA to perform the impossible, s ee Cement Kiln , 255 F.3d at 871, and that includes recording emission levels that are not accurately detectable with its current emissions testing technology. As EPA explains the issue, emission levels from zero up to some value above the method detection level cannot be stated with accuracy. Because any emission level EPA selects at that point will necessarily be an estimate, EPA adopted a method to account for measurement imprecision that has a rational basis in the correlation between increased emission values and increased testing precision.”

39. Comment: One commenter (1042

- 0347) contended that the EPA may not lawfully account for malfunctions in setting standards, and thus may not use the UPL method because it accounts for variability that builds in potential malfunction

- caused higher emissions as a pote ntial driver of the floor. The commenter opined that use of the UPL is just as likely to create a weaker standard due to sources operating improperly as it is to account for any other causes of variability. The commenter contended that use of the UPL metho d is unlawful and arbitrary because the EPA does not explain how use of the UPL method will avoid accounting for malfunctions in setting standards.

Response : There is nothing in CAA section 112 that directs the a gency to consider malfunctions in determinin g the level “achieved” by the best performing sources when setting emission standards. As the D.C. Circuit has recognized, the phrase “average emissions limitation achieved by the best performing 12 percent of” sources “says nothing about how the

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performan ce of the best units is to be calculated.” Nat'l Ass'n of Clean Water Agencies v. EPA

, 734 F.3d 1115, 1141 (D.C. Cir. 2013). As discussed above, nothing in CAA section 112 requires the a gency to consider malfunctions as part of that analysis, accounting fo r malfunctions in setting emission standards would be difficult, if not impossible, and could lead to standards that are not reflective of levels achieved by a well

- performing non

- malfunctioning source.

Regarding the commenter’s assertion that use of the U PL is unlawful and arbitrary because we do not explain how to avoid accounting for malfunctions when setting standards, the EPA does not use emissions test data collected from processes during malfunctions to establish emissions standards.

40. Comment: One co mmenter (1041

- 0081) argued that the EPA should use the average, not a high variability factor, in setting the MACT standards for these pollutants, as use of a variability factor is unsupported and results in a standard that is higher than appropriate.

The commenter noted that the EPA may consider variability in calculating the best sources’ performance. The commenter contended that the EPA’s method of considering variability seeks to assure that none of the sources among those identified as best performers would ever exceed the floor level which ignores the reality that sources’ emission levels are largely within their control. The commenter claimed that a great deal of variability may be statistically conceivable if the EPA chooses a high enough prediction limit (in this case the 99th percentile), but that does not mean that a well

- run source actually would experience such variability. Indeed, the commenter asserted that one of the main points of having emission standards is to ensure that sources not only d eploy the appropriate control measures, but use those control measures properly and consistently to minimize emissions.

Citing dicta in a 1999 D.C. Circuit decision ( Sierra Club v. EPA , 167 F.3d 658, 665), the commenter stated that industry groups have arg ued that EPA should set weak standards to accommodate sources’ worst reasonably foreseeable performance. According to the commenter, those dicta have no precedential value and do not bind the EPA’s rulemaking in any way. The commenter further stated that e ven if they constituted a holding

– which they do not

– they do not apply to the EPA’s floors for existing sources. Moreover, the commenter observed that the underlying assumption

– that if a particular standard reflects what a given source achieves in
pra ctice, that source will never violate the standard

– is plainly flawed. No matter what level a given source normally achieves in practice, the commenter asserted that the source may emit far higher levels if it is not run properly. The commenter cited the following example: if a careless operator allows a combustion unit to operate outside the proper parameters for temperature and pressure, its emissions may increase. Likewise, the commenter observed that if a baghouse is not properly maintained or the pres sure drop is allowed to exceed the proper parameters, emissions may increase.

According to the commenter, the high emissions that occur when a source is poorly operated must be treated as exceedances or violations of the emission standards, even though it is foreseeable that periods of sloppy or negligent operation may occur even at the source with the lowest emission tests. The commenter argued that floors should not be set at a level that the best performers could never exceed even when they operate poorl y or fail to maintain their control equipment. Indeed, the commenter claimed that such an approach violates CAA section

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112(d)(3) and frustrates its intent. The commenter asserted that floors must be set at the average emission level achieved by the best p erformers when they are operating properly. The commenter contended that using a UPL approach to set standards reflecting the worst performance these sources could have in a purely statistical sense does not yield an accurate picture of the best sources’ a ctual performance, and it is especially arbitrary in the absence of any explanation of why EPA thinks that the relevant best sources’ performance would ever be so bad, other than the fact that it is statistically possible.

Response: We disagree with the co mmenter that the EPA should use the short

- term average in setting MACT standards. We also disagree with the comment that using the UPL in MACT floor calculation does not yield an accurate picture of the best sources actual performance. As explained in two memoranda submitted to the docket in support of the 2014 supplemental proposal (the limited data sets memorandum and the UPL memorandum), the UPL represents the average emission limitation achieved by the best performing 12 percent (or best 5 sources for s ubcategories with fewer than 30 sources) as required by the statute. S ection 112(d)(3) of the CAA requires the EPA to promulgate standards for major sources of HAP that are based on MACT performance. For existing sources, MACT standards must be at least as stringent as the average emission limitation achieved by the best performing 12 percent of existing sources (for which the Administrator has emissions information) or the best performing 5 sources for source categories with less than 30 sources. For new s ources, the MACT standards must be at least as stringent as the control level achieved in practice by the best controlled similar source. CAA Section 112(d)(3). In construing CAA section 112(d)(3), the D.C. Circuit has stated that “[t]hough section 7412(d) (2) does direct EPA to require the maximum emission reduction that it determines to be achievable, section 7412(d)(3) provides that the maximum degree of reduction in emissions that is deemed achievable... shall not be less stringent that what the best

- per forming sour ces achieve. Section 112(d)(3) therefore limits the scope of achievable in section 7412(d)(2).” Sierra Club v. EPA , 479 F.3d at 878. (Internal quotations omitted). As the Court has also explained “[i]t is reasonable to suppose that if an emissi ons standard is as stringent as the emissions control that is achieved in practice by a particular unit, then that particular unit will not v i o la te the standard. This only results if “achieved in practice” in CAA section 112(d)(3) “to mean achieved under t he worst foreseeable circumstances.” Sierra Club v. EPA , 167 F.3d 658, 665. Moreover, the Court has further stated that “to comply with the statute, EPA’s method of setting emissions floors must reasonably estimate the performance of the best performing plants.” Id . And

, that “EPA would be justified in setting the floor as a level that is a reasonable estimate of the performance of the best controlled similar unit under the worst reasonably foreseeable circumstances.” Id . Earlier, in National Lime Ass’n v. EPA , 627 F.2d 416, 431 n.46, the Court also stated that “where a statute requires that a standard be achievable it must be achievable under most adverse circumstances which can reasonably be expected to recur.” As we have explained in various rules, CAA section 112(d)(3) does not address the question of whethe r, in assessing which sources perform best or are best controlled, emission levels should be evaluated either over time or in a single test result. We believe, however, that our MACT floor calculation should identify the best performers (i.e., the best per forming 12 percent or best performing five sources in smaller source categories for existing sources, and the best controlled single source for new sources) as those sources likely to emit the least HAP over time considering variability. Further, the D.C. Circuit has held repeatedly that variability of best performing sources may be taken into account in establishing MACT floors. Sierra Club v. EPA

, 479 F.3d at 881

- 882. See also National Lime Ass’n v. EPA

, 627 F.2d 416, 431 n.46, 443 (D.C.

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Cir. 1980). There fore, we believe it is appropriate to consider statistical variability in order to ensure that units could meet the floors at all times.

Further, in the context of development of MACT floors, the UPL is a value, calculated from a dataset, which identifies the average emissions level that a source or group of sources is meeting and would be expected to meet a specified percent of the time that the source is operating. As explained in our November 13, 2014 supplemental proposal, c ontrary to the commenter’s as sertion, the NACWA court did not find the UPL to be an arbitrary approach, but simply asked for a better explanation from the Agency. The UPL memorandum provides the explanation of what the UPL represents sought by the NACWA Court. It also explains why the UPL is representative of the level of performance achieved by the best performing unit or units. The court did not state that the “average emissions limitation achieved by the best performing 12 percent” must be equal to the mean of the available data, as suggested by the commenter, and in past decisions the court has upheld that it is appropriate for EPA to account for variability when establishing numeric MACT standards. See Mossville Environmental Action Now v. EPA , 370 F.3d 1232, 1241

- 42 (D.C. Cir. 200 4).

We also refer the commenter to the proposal MACT floor memorandum, which is in the rulemaking docket. This memorandum provides a detailed discussion of the EPA’s authority to consider variability, especially given that MACT and other technology

- based s tandards are necessarily derived from short term emissions test data and such data are not representative of the range of operating conditions that the best

- performing facilities face on a day

- to

- day basis. In statistical terms, each test produces a limite d data sample, not a complete enumeration of the available data for performance of the unit over a long period of time. The EPA, therefore, often needs to adjust the short

- term data to account for these varying conditions in order to properly estimate thes e sources’ performance over time. The types of variability that the EPA accounts for include variability between and within tests at the same unit as well as between units in the pool of “best performing units”. This memo also describes the EPA’s selection of the UPL methodology to address such variability

. Additionally, the EPA has incorporated new data and data corrections received during the public comment period that were based on all emission stack test data of appropriate quality available to the EPA. (“ EPA typically has wide latitude in determining the extent of data

gathering necessary to solve a problem. We generally defer to an agency's decision to proceed on the basis of imperfect scientific information, rather than to invest the resources to cond uct the perfect study. ” Sierra Club v. EPA , 334 U.S. App. D.C. 421, 167 F.3d 658, 662 (D.C. Cir. 1999) (citation omitted) )

. As a result, we have revised the appropriate limits in the final rule. These calculations can be found in the memoranda “Revised MAC T floor Analysis for the Wool Fiberglass Manufacturing Source Category” and “Revised MACT floor Analysis for the Mineral Wool Production Source Category,” which are in the docket for this rulemaking.

D. SSM Provisions

41. Comment : One commenter (1041

- 0073/1042

- 01 11) stated that the 2011 amendments to the SSM provisions make the rule more stringent and that the EPA does not have this authority.

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The commenter supported their assertion noting that CAA section 112(d)(6) tells the EPA to “review and revise as necessa ry (taking into account developments in practices, processes, and control technologies), emissions standards promulgated under this section no less often than every 8 years.”, but that the EPA did not invoke its authority under CAA section 112(d)(6) to
sup port the SSM provisions in their 2011 proposal (see, e.g., 76 Fed. Reg. at 72794 cols. 1

- 2). The commenter continued, stating that CAA section 112(d)(6) does not provide broad authority to reconsider aspects of previously issued MACT standards unrelated to “developments in practices, processes, and control technologies.” Thus, the commenter questioned the EPA’s authority to revise the standard as it does with the proposed SSM Provisions.

Per the commenter, reassessing existing NESHAP that were based on the MACT floor now, and imposing more

- stringent requirements, would be inconsistent with the statute’s provision of technology

- review and residual

- risk authority to follow establishment of MACT standards and with Congress’s desire for finality evident in the judicial review provisions of CAA section 307(b).

The commenter stated that challenges to MACT standards needed to be raised within 60 days of their promulgation. The commenter highlighted that this provision ensures that regulated entities, the EPA, and the public know what emission limitations will apply to the source, rather than having those limitations be subject to flux. In the instant case, the commenter contended, facilities regulated by the two NESHAP long ago made capital investment decisions and developed and honed their operating procedures to meet the existing MACT standards. The commenter highlighted that CAA does not allow the EPA simply to revisit the analysis and decisions involved in developing emission standards that meet the requirements of CAA sections 112(d)(2) and (3).

Response: In the 2011 proposal (76 FR 72775, 72794), we explained that the D.C. Court had recently vacated the SSM exemption contained in 40 C.F.R. sections 63.6(f)(1) and 63.6(h)(1). Sierra Club v. EPA , 551 F.3d 1019 (D.C. Cir. 2008) cert. denied, 130 S. Ct 1735 (2010). The exemptions for startup and shutdown and for malfunctions in subpart DDD (Table 1 and 63.1180(d)) and NNN (Table 1) are inconsistent with the holding in Sierra Club that emissions lim itations under CAA sectio n 112 must apply continuously. Thus, EPA is eliminating the SSM exemption in subpart s DDD and NNN. The EPA does not claim that the Sierra Club case constrains its authority to prescribe unique standards for startup and shutdown or malfunction periods.

In the 2011 proposal, the EPA also explained that unique standards were not necessary for periods of startup and shutdown. Some industry representatives believe, based on observations, that emissions during periods of startup and shut down are lower than emissions during production. Other industry representatives believe, based on observation, that startup and shutdown emissions may be higher for some pollutants while other pollutants are not emitted at all during such periods. However, with the exception noted below, no industry representatives provided emission monitoring, testing, or records of visual emissions observations in support of separate emission limits for startup or shutdown. We explained that the pollutants emitted from th ese processes are captured and controlled by the technologies in place regardless of the concentration of pollutant loading at the inlet to the control devices. We also explained that

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applicable control devices are started up prior to the process units and are also operational during the shutdown phase of the process. (76 FR 72794).

We therefore continue to believe that unique standards are not necessary for periods of startup and shutdown . In the final rule, we are establishing work practice standards th at apply at all times.

With regard to our approach to periods of malfunctions, we explained in the 2011 proposal that while periods of startup, normal operations and shutdown are all predictable and routine, malfunctions in contrast are “sudden, infrequent and not reasonably preventable failure of air pollution control and monitoring equipment, process equipment or a process to operate in a normal or usual manner.” (40 CFR 63.2) As the preamble explained, the EPA has determined that CAA section 112 does not require that emissions that occur during periods of malfunction be factored into development of CAA section 112 standards. That approach is consistent with CAA section 112 and is re asonable. (72 FR 72794).

Further, the commenter is incorrect that CAA sect ion 112(d)(6) provides the exclusive authority to address standards that apply during SSM events. In Medical Waste Institute v. EPA

, 645 F.3d 420, 425

- 27 (D.C. Cir. 2011), the D.C. Circuit held that the EPA may permissibly amend improper MACT determination s, including amendments to improperly

- promulgated floor determinations, using its authority under CAA sections 112(d)(2) and (3). Similarly, the absence of standards for periods of startup and shutdown and periods of malfunction is not proper. Sierra Club v. EPA , 551 F.3d 1019 (D.C. Cir. 2008) cert. denied, 130 S. Ct 1735 (2010); see also Medical Waste Incinerator

, 645 F.3d at 426 (resetting MACT floor, based on post

- compliance data, permissible when originally

- established floor was improperly established). Additionally, Portland Cement Ass’n v. EPA

, 665 F.3d 177, 189 (D.C. Cir. 2011) confirms that “nothing prohibits the EPA from reassessing its standards more often” than every 8 years under CAA section 112(d)(6). The commenters are thus incorrect that CAA s ection 112(d)(6) provides the exclusive authority to address standards that apply during SSM events. Here, the EPA adopted no MACT standard at all during SSM events, an approach soundly rejected by the D.C. Circuit in Sierra Club v. EPA , 551 F.3d 1019. Con sequently, the emission limits of the final rule apply at all times, including during periods of SSM.

42. Comment: One commenter (1041

- 0073/1042

- 0111) stated the proposed SSM provisions are not required in order to be consistent with Sierra Club v. EPA and that it is unreasonable to require sources to meet technology

- based emission standards during SSM periods. See 40 CFR section 60.8(c). The commenter believes this opinion is supported by the exemption of SSM periods under and incorporation by reference of the General Provisions SSM requirements in numerous MACT standards, but also noted that the Mineral Wool MACT specifically exempts SSM events rather than relying solely on reference to the General Provisions.

According to the commenter, the EPA suggested that its treatment of excess emissions during SSM events in the 2011 proposal is appropriat e, even “required,” in order to make the standards “consistent with” the D.C. Circuit’s decision in Sierra Club v. EPA , 551 F.3d 1019 (D.C. Cir. 2008), cert. denied, 130 S. Ct. 1735 (2010), which vacated the exemption for excess emissions during SSM events contained in the 40 CFR part 63, subpart A General Provisions for

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emission standards for HAP under CAA section 112. See, e.g., 76 Fed. Reg. at 72775, col. 3; 72787, col. 2; 72794 col. 1

- 3; 72795, col. 2

- 3. The commenter stated that D.C. Circuit’s Sierra Club decision does not compel or support the proposed SSM provisions because of the following:

1. The Sierra Club decision interpreted the NESHAP Genera l Provisions, but did not dictate what the EPA may or may not include in category

- specific MACT standards. See 40 CFR. section 63.1180(d); see also July 22, 2009 letter to counsel from Adam Kushner, Director of EPA’s Office of Civil Enforcement, Table 2 (stating that
stan dards in 40 CFR. part 63 subpart DDD, among others, are “not affected” by the Sierra Club decision).

2. The Sierra Club decision does not preclude the EPA from applying different standards during SSM events than apply during normal operations, adding that section 302(k)’s “inclusion of [the] broad phrase” “any requirement relating to the operation or maintenance of a sourc e to assure continuous emission reduction” in the definition of “emission standard” suggests that MACT standards can be consistent with CAA section 112 “without necessarily continuously applying a single standard.”

The commenter added that legislative prec edent, court precedence, and the language of CAA section 112(h) supports application of a different standard during SSM events. The commenter stated that the language that the D.C. Circuit considered dispositive in interpreting EPA’s standards

- setting auth ority under CAA section 112 has been in the statute since 1977, that the language in section 302(k) of section 111 exempted SSM periods, that sources are not required to meet NSPS emission limits under CAA section 111, and that nothing in the legislative h istory of the 1977 amendments to the CAA that suggests Congress intended to overturn that practice. See 40 CFR. S ection 60.8(c)

.
The commenter continued that court decisions both before and after the CAA Amendments of 1977 have affirmed that special SSM pr ovisions are appropriate in CAA section 111 standards despite the “continuous basis” language in the definition of “emission limitation.” The commenter extended the NSPS rationale to MACT continuing that the legislative history of the CAA Amendments of 199 0 does not suggest Congress intended different meanings in both 111 and 112 language for the same terms “emission standard” and “emission limitation,” in the 1990 amendments directing EPA to establish MACT standards.

Additionally, the commenter cited that the Sierra Club decision did not address EPA’s authority to set a “design, equipment, work practice or operational standard,” in lieu of a numerical emission limitation under CAA section 112(h) for SSM events. The commenter stated EPA told the Court that t he General Provisions SSM exemption struck down in Sierra Club was not an alternative standard based on the work practice standard authority. See 551 F.3d at 1028. The commenter believes EPA argued in that case that CAA section 112(h) was irrelevant to its authority to exempt excess emissions during SSM events, contending that even the “best performers” may be unable to achieve the emission limits of a MACT standard established for normal operations during SSM events.

The commenter argued that the approach the EPA is proposing would not establish the required “continuous CAA section 112

- compliant standards” because MACT emission standards

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must be “achievable”, and “achieved” by the best performers. See CAA section 112(d)(3). The commenter continued that the courts recognize that a “technology based standard discards its fundamental premise when it ignores the limits inherent in technology.” NRDC v. EPA , 859 F.2d 156, 208 (D.C. Cir. 1988). The commenter cited an example of this from the D.C. Circuit: Portland Cement Ass'n v. Ruckelshaus , 486 F.2d 375, 398 (D.C. Cir. 1973), in a decision reviewing standards under CAA section 111, that “‘start

- up’ and ‘upset’ conditions due to plant or emission device malfunction, is an inescapable aspect of industrial life and t hat allowance must be made for such factors in the standards that are promulgated.” Id . at 399. Another example cited by the commenter stated that in Essex Chem. Corp. v. Ruckelshaus , 486 F.2d 427, 432 (D.C. Cir. 1973), cert. denied, 416 U.S. 969 (1974), t he court held that SSM provisions are “necessary to preserve the reasonableness of the standards as a whole.” Id . at 433. The commenter contended that in National Lime Ass’n v. EPA , 627 F.2d 416 (D.C. Cir. 1980), a third case reviewing emission standards p romulgated under CAA section 111, the court held that the CAA requirement that NSPS be “achievable” means that the standards must be capable of being met “on a regular basis,” including “under most adverse circumstances which can reasonably be expected to recur,” including during periods of SSM. 627 F.2d at 431 n.46.

Arguing that the CWA in this regard is analogous to the CAA, the commenter continued that courts have reached a similar conclusion under the CWA requirements that the EPA establish technology

- b ased effluent limitations based on the best available control technology. The commenter cited one such case in which the court held that where the EPA knew that there would be periods where a discharger, even with “exemplary use of” the identified best
tec hnology, would exceed the effluent limitations because of conditions “beyond the control of the permit holder,” the EPA had violated the CWA by failing to provide an “upset provision” to address those periods. Marathon Oil Co. v. EPA , 564 F.2d 1253, 1273

- 7 4 (9th Cir. 1977). 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 limitations, which are tied to achieving water qu ality standards rather than based on available technology, and therefore need not include an upset provision).

The commenter stated that, in the preamble to the 2014 proposal, the EPA acknowledges this precedent, but suggests that “intervening case law suc h as Sierra Club v. EPA and the CAA 1977 amendments undermine the relevance of these cases today.” 76 Fed. Reg. at 72795 col. 3. According to the commenter, the EPA does not explain why it believes that to be the case but contends Sierra Club v. EPA did no t address this precedent, and the 1977 CAA amendments support the conclusion that emission standards should account for the inability of a source to meet the normal emission limits during particular circumstances. Moreover, the commenter contended that Nat ional Lime Association decision discussed above, which relied in part on the cases the EPA referenced in the preamble, and which addresses the need for emission limits that address reasonably anticipated adverse circumstances, post

- dates the CAA Amendments of 1977 by 3 years.

The commenter also stated that the Sierra Club decision did not prohibit the EPA from setting a “requirement relating to the operation or maintenance of a source to assure continuous emission reduction” as the emission standard to appl y to malfunctions. See 551 F.3d at 1027. The commenter contended that the Sierra Club decision only rejected the EPA’s assertion that it had discretion to decide not to impose any emission standard covering SSM periods. See Id . at

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1027

- 28, 1030 (noting that the EPA was not claiming that the General Provisions SSM exemption was either an emission standard under CAA section 112(d) or a design, equipment, work practice, or operational standard under CAA section 112(h)).

The commen ter argued that, despite implications to the contrary, the Sierra Club decision recognized that different standards may (and in some cases must) apply during non

- standard operating conditions, such as SSM.

Response: As explained in our responses to other c omments in this section, the exemptions for startup and shutdown and for malfunctions in subparts DDD and NNN promulgated in 1999 are inconsistent with the holding in Sierra Club that emissions limitations under CAA section 112 must apply continuously. As also earlier explained, we do not claim that the Sierra Club decision constrains our authority to prescribe unique standards or work practice standards during startup and shutdown periods where such standards are justified. We have evaluated whether differ ent standards during startup and shutdown periods are justified, and in this case, we believe different standards are not warranted. We maintain that control devices, such as baghouses for PM and metal HAP particulate control and regenerative thermal oxidi zers (RTOs) for control of COS, are started prior to process units in use by these sources and are also operational during the shutdown phase, and to require that the emission limits apply at all times.

However, based on comments received from representat ives of the wool fiberglass industry during a December 12, 2012 meeting discussing this and other topics, we added a provision in the April 15, 2013 supplemental proposal that required sources to demonstrate compliance with the limits during periods of sta rtup by showing the emissions are routed to the control device operated at the same conditions that showed compliance with the standard during the most recent performance test. In the 2014 supplemental proposal, we added a requirement for facilities to mai ntain records that show that only clean fuels were used during startup and shutdown periods. We also added a requirement for cold

- top furnaces at wool fiberglass facilities to maintain records that show that only cullet was used as the raw material during startup.

With respect to periods of startup and shutdown, we agree that in some circumstances, separate standards for such periods may be appropriate. However, as explained in the preamble to the 2013 proposal (78 FR 22378), we believe our approach to pe riods of startup and shutdown is reasonable because we have taken into account these periods and expect sources will be able to meet emission limits during such periods based on comments the agency received on its various proposals. The EPA has established work practice standards in this rule that apply during startup and shutdown periods

. For periods of malfunction, the EPA provided a detailed justification for its approach to malfunctions in the preamble to the 2011 proposed rule (76 FR 72794). As the D .C. Circuit noted in Sierra Club v

. EPA , 167 F.3d 658 (D.C. Cir. 1999), the phrase "average emissions limitation achieved by the best performing 12 percent of units” in section 112 of the CAA "says nothing about how the performance of the best units is to be calculated.” Id . at 661. Congress has not directly addressed the issue of whether emissions that occur during periods of malfunction must be taken into account in calculating the performance of the best units and the EPA’s approach to malfunctions is re asonable for the reasons set out in the preamble to the proposed rule. The EPA further explained that the performance of units that are malfunctioning is not

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reasonably foreseeable and cited case law supporting its approach to malfunctions. See Sierra Cl ub at 665 (discussing need to take into account the worst reasonably foreseeable performance) and Weyerhaeuser v

. Costle , 590 F.2d 1011, 1058 (D.C. Cir. 1978) (“In the nature of things, no general limit, individual permit, or even any upset provision can ant icipate all upset situations.”). Although the EPA bases emission standards on different manners of operations and circumstances, the EPA only takes into account conditions that are “foreseeable” and “which can reasonably be expected to recur.” Sierra Club

, 167 F.3d at 665; see also Nat. Lime , 627 F.2d. at 431, n.46. Virtually no malfunction is foreseeable in terms of its nature, timing or effect on emission levels and no operator knows if or when a malfunction could recur.

With respect to commenters’ sugges tion that EPA consider work practice standards, the decision to use a work practice standard is wholly within the discretion of the EPA. See CAA section 112(h) (“[T]he Administrator may , in lieu [of a numeric standard], promulgate a design, equipment, work practice, or operational standard, or combination thereof.”). In exercising the option to establish a work practice standard, that standard must “ in the Administrator’s judgment [be] consistent with the provisions of subsection (d) or (f).” CAA section 11 2(h)(1) (emphasis added). These subsections make clear that the EPA is to base emission standards on the emission levels already achieved by the best performing sources and to ensure that public health is protected, as applicable. This means that work prac tice standards, although written in non

numeric form, must still satisfy statutory requirements such as those applicable to MACT standards, including the requirement to be no less stringent than the MACT floor.

It is just as difficult to establish a work p ractice standard for malfunctions that can approximate the level of emission reduction achieved by the best performing sources during malfunctions as it would be to factor emission levels that occur during malfunctions into the numeric standards, as discus sed above, the EPA would have to design a single work practice standard that applies equally to a tank explosion as it does to innumerable types of operator error, computer glitches or a myriad of other unknown events, or alternatively create innumerable w ork practice standards.

In summary, the EPA believes that, based on this rulemaking record, it would be clearly inappropriate to set a work practice standard for malfunctions in lieu of the otherwise applicable numerical emission limit. We also note that w e would consider any response to violations caused by a malfunction on a case

- by

- case basis through the exercise of enforcement discretion. Regarding startup and shutdown periods, we do not replace the emission limits with a work practice standard, but we provide an option for companies to demonstrate compliance with the standard during periods of startup and shutdown. Thus, contrary to the commenter’s argument, we believe that the standards that apply during startup and shutdown periods will establish “con tinuous section 112

- compliant standards” that the Sierra Club decision concluded are required. We also disagree with the comment that the Sierra Club decision “did not by its terms” concern what EPA may or may not include in category

- specific MACT standard s. (Citing letter to counsel from Adam Kushner, Director of EPA’s Office of Civil Enforcement, July 22, 2009 (see Table 2 of the letter)). This letter, which addressed potential compliance issues arising from the Sierra Club court decision, contained EPA’s plans for addressing those concerns, including potential future revisions to CAA section 112(d) standards. As explained in the letter, our initial analysis indicated that certain rules, such as the mineral wool production NESHAP, included specific regulatory text exempting or excusing compliance during SSM events in addition to

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cross

- r eferences to 40 CFR. S ections 63.6(f)(1) and 63.6(h)(1). At the time, we indicated that the vacatur in Sierra Club would have no direct impact on such source category

- specific SSM provisions because we believed these provisions were not challenged in Sierr a Club . We, however, also recognized that the legality of those source

- category specific provisions may have been called into question and indicated that we were evaluating them in light of Sierra Club

. “The tables attached to this letter are based on the EPA‘s initial analysis and are, therefore, subject to change.” (p. 3) [footnote omitted]. We have now evaluated the relevant provisions and determined that they need to be revised to address the Sierra Club decision.

We disagree with commenters claim that case law under the CAA and CWA supports its argument that EPA’s approach to startup and shutdown and malfunction periods is inconsistent with CAA section 112. As explained above and in the preamble to the 2013 and 2014 proposed rules, the EPA has taken int o account startup and shutdown periods in determining appropriate standards. Further, the case law cited by commenters does not undermine the EPA’s approach to malfunctions. As noted in the preambles to the 2013 and 2014 proposed rules, the relevance of Po rtland Cement and Essex Chem. Corp . is questionable in light of subsequent case law and the 1977 amendments to the CAA definition of emission standard requiring that such standards be continuous. As the D.C. Circuit noted in National Lime v

. EPA , 627 F.2d. 416, 434 at n 54, “[w]hether the 1977 Amendments have effectively repealed the regulations permitting flexibility to account for startups, shutdowns and malfunctions regulations applauded by this court in Portland Cement I , 486 F.2d at 398

- 99 is certainly unclear.” The EPA’s approach to malfunction is consistent with CAA section 112 and is a reasonable interpretation.

In any event, the EPA’s overall approach to malfunction events in this rule is consistent with the approach set forth in the EPA’s 1972 p roposed rules cited favorably in Portland Cement and Essex Chemical in that both EPA’s approach today and in 1972 impart a construction of "reasonableness" to the standards as a whole and adopts a more flexible system of regulation than can be had by a sys tem devoid of "give." Portland Cement at 399. Portland Cement and Essex criticized the EPA regulations that contained no specific provisions to address malfunctions and the EPA‘s assertion that malfunctions would be dealt with by the informal exercise of d iscretion in the a gency‘s enforcement activities. Those decisions did not require exemptions or less stringent standards for malfunction events as the commenter suggests.

The NRDC v

. EPA ( 859 F.2d 156, 207(D.C. Cir. 1988)) case cited by commenter interpre ts provisions of the CWA that are different in nature than provisions governing standards under section 112 of the CAA. Furthermore, the discussion of technology

- based standards in the NRDC case is dicta. Nevertheless, the EPA‘s approach to malfunctions is also consistent with NRDC

.

43. Comment: One commenter (1041

- 0073/1042

- 0111) stated that the EPA should fully justify applying the same emission limitations during startup and shutdown as during normal operations.

The commenter contended that it is not appar ent from the cursory treatment of this issue in the preamble, however, that the EPA has sufficiently justified the conclusion that emissions during startup and shutdown would be no greater than during normal operations, adding that a control device may be less efficient when the pollutant concentrations in the gases to be treated

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are lower than during steady state operation (as they often will be when a process is starting up or shutting down). See, e.g., 68 Fed. Reg. 1276 at 1287

- 88 (January 9, 2003). The commenter noted that higher emissions may occur during startup and shutdown, either on a total mass basis or on a mass per unit of production basis. See, e.g., 76 Fed. Reg. 63878, 63883 col. 2 (October 14, 2011).

The commenter stated that, even if the EPA did have authority to go back and change the existing MACT standards, the EPA would have to justify why the decisions reflected in the current standards are wrong and why the new standards meet the required criteria that the EPA should satisfy in issuing MACT standards under CAA sections 112(d)(2) and (3). The commenter stated that the EPA did not ma k e either showing in the 2011 proposal.

The commenter argued that the EPA has not analyzed sufficient data on emissions during startup and shutdown to justify the conclusion that the emission limits should apply at all times, and that the EPA should conduct a thorough analysis to determine whether the best

- performing sources (the MACT floor) achieve the same emission limitation during startup and shutdown as dur ing normal operations.

The commenter noted that adequate data do not often exist to establish emission limits for periods of startups and shutdowns because regulations generally prohibit compliance testing during SSM conditions, instead requiring data to be obtained during normal operating conditions. Also, the commenter stated that atypical pollutant concentrations outside of the monitoring equipment’s span, stack conditions outside of QA/QC parameters, and limitations of the monitoring equipment may yiel d unusable data, or data that would understate emissions during startup and shutdown periods.

The commenter added that a clear demarcation of startup, shutdown, and malfunction events is needed to avoid confusing one event with another in the data sets. T he commenter surmised that the EPA may be analyzing data for malfunctions that should be included in startup or shutdown emission calculations.

Response: We disagree with the comment that the agency provided a “cursory” description of the proposed startup and shutdown provisions. As explained in the 2011 proposal (76 FR 72775, 72794), the D.C. Court had recently vacated the SSM exemption contained in NESHAP General Provisions (40 CFR sections 63.6(f)(1) and 63.6(h)(1)). Therefore, we eliminated the SSM exem ption in subparts DDD and NNN and proposed that the emission limitations under CAA section 112 must apply continuously. I n the April 2013 proposal, we withdrew our previously

- proposed alternative emission limits for startup and shutdown, and instead proposed that sources may demonstrate compliance with the MACT floor emission limits during periods of startup and shutdown. Also, i n our November 2014 no tice , we proposed work practice standards for startup and shutdown periods, under CAA section 112(h), based on comments regarding the practices used by the best performers among mineral wool producers to minimize emissions during these activities

. As expl ained in the 2013 and 2014 proposals, industry trade association conducted a voluntary survey among all owners and operators of mineral wool and wool fiberglass manufacturing facilities. The survey sought test data for PM, CO, and HAP emissions and

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informa tion on process equipment, control devices, point and fugitive emissions, practices used to control point and fugitive emissions. The survey also sought emissions data during periods of startup and shutdown. (Form D of Enclosure 1). We did not receive any relevant data for periods of startup and shutdown in response to the survey. We also note that although we again requested test data for startup and shutdown events at proposal, the EPA did not receive any relevant data on startup and shutdown in response to the survey.

The EPA is allowed to set standards using available information, under CAA section 112(d)(3)(A) (Standards are to be based on the average emissions limitation achieved by the best performing units “for which the Administration has information).” Further, a s earlier explained, we do not claim that the Sierra Club decision constrains our authority to prescribe unique standards during SSM periods.

We also disagree with the comment that there is no demarcation between malfunctions and startup and shutdown even ts. As explained at proposal (79 FR 68015, November 13, 2014), the EPA believes that malfunction events should be treated differently than periods of startup and shutdown, which are predictable and routine aspects of a source’s operations. As also explaine d, the EPA has determined that CAA section 112 does not require that emissions that occur during malfunctions be factored into development of CAA section 112 standards. Because startup and shutdown periods are part of a source’s standard operating procedur es, the same approach to compliance with, and enforcement of, applicable emissions standards during those periods should apply as otherwise applies during a source’s operations.

While the starting up or shutting down of a batch or continuous process is pa rt of a regulated source’s standard operating procedures, it is not a period of normal production, that is, no mineral wool melt or usable glass is being produced during periods of startup and shutdown. If data were collected for either source category dur ing periods of startup, shutdown or malfunction, those data would not be representative of normal operations, and would not be used to determine the emissions limits for normal production periods in the source categories. Such data would only be used to de termine emission limits for periods of startup and shutdown. Because our emissions testing methods are currently only valid for periods of normal production, sources correctly tested only during such periods, and did not test for periods of startup or shut down. If, in the future, new methods are developed for periods of startup and shutdown, we will consider amendments to these rules for such testing at that time.

As explained in response to earlier comments in this section, pollutants emitted from these in dustry processes are reduced by the control devices regardless of concentration at the inlet loading of the control device. Therefore, properly operated controls (that is, controls operated at the parameters established at the most recent successful perfor mance test) would achieve the same emission limit as during normal operation. We therefore disagree with the commenter that even the best performers may not achieve the standards during periods of startup and shutdown.

In the final rule, the EPA has estab lished work practice standards that apply during startup and shutdown periods . See 40 CFR 63.1197 and 63.1 388.

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44. Comment: One commenter (1042

- 0299) objected to the EPA proposing to allow sources to demonstrate compliance during startup and shutdown by showin g that the emissions were controlled during these periods, because the commenter believes this amounts to an exemption from the standard

-- rather than compliance with the standard

-- during startup and shutdown periods. The commenter sees this requirement as only a recordkeeping exercise, not as a provision that limits emissions to levels that meet the limits of the proposed rule. The commenter believes this approach undermines enforcement of the rule and asks how the EPA enforces a recordkeeping provision to ensure compliance with a limit. The commenter also believes that this approach undermines citizen enforcement because these records cannot be accessed by the community. In an earlier letter submitted in r e spon s e to the 2011 proposal (1041

- 0081), the commen ter suggested that the EPA should implement strong enforcement provisions to prevent emission spikes, malfunctions and other violations in a way that will be enforceable by citizens in the Title V permits for these source categories. The commenter asserted that the past exemption during periods of startup, shutdown, and malfunction shows the need for strong enforcement of the EPA’s standards to apply at all times.

In the more recent comments (1042

- 0299), the commenter asked why the EPA has not required work practices for startup and shutdown periods (e.g., use of certain raw materials, preheating empty furnace) for wool fiberglass facilities (major sources) as the EPA discussed in the preamble to the 2012 proposal b ecause work practices establish specific re quirements to ensure compliance with the emission limit. The commenter added that, to establish work practice standards, the EPA must demonstrate that an “alternative standard” is technologically or economically impracticable or is consistent with CAA subs ection (d) or (f). The commenter noted that, in the original rule, the EPA acknowledged it has data to assess compliance during startup and shutdown (78 FR 22378, 22388).

Response: In the 2013 and 2014 proposals, we stated that the limits of the rule apply at all times. However, because emissions during startup and shut down periods are not at steady state (which is necessary for accurate emissions testing) and cannot be measured (as discussed in section V I .D of the preamble to the final rule ), we considere d ways in which a source could demonstrate that they meet the limits of the rule. One way to do this is to control the process emissions at all times using a control device that is operated at the same parameters as when the source conducted the most recen t successful performance test, that is, the compliance test showing that the source met the limits. The control devices used in these processes are wet and dry electrostatic precipitators and fabric filters (baghouses). These types of controls achieve the same level of emission reduction regardless of loading as long as they are properly maintained and operated. However, to determine whether a control is properly maintained and operated, adequate recordkeeping must exist that documents the parameters of ope ration, frequency of maintenance and monitoring. Thus, the requirements of startup and shutdown are that sources must control all emissions during these periods and also must keep records of their operating, maintenance, and monitoring that demonstrate the controls are operational and properly functioning.

Additionally, we do not believe this weakens or compromises the ability to enforce the rule, because it is straightforward to determine if sources can demonstrate compliance with the limits during startu p and shutdown. Regarding citizen enforcement, failure of owners or operators to maintain records of control device operation during startup and shutdown periods

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would be a violation of the standards. U nder the provisions of 40 CFR 63.15, the public can

re quest access to reports submitted to the regulatory agency whenever they choose, with the exception of information protected through 40 CFR part 2 (e.g., CBI ). In addition, as discussed in section IV.F of this document, we are promulgating requirements for electronic reporting of emissions test data that will improve public access to emissions information.

Regarding work practice standards, we did not replace the emission limits with a work practice standard, but we provided an option for owners or operator s to demonstrate compliance with the standard during periods of startup and shutdown. Thus, contrary to the commenter’s argument, we believe that the standards that apply during startup and shutdown periods will establish “continuous section 112

- compliant standards” that the Sierra Club decision concluded are required.

Regarding the assertion that the EPA had previously indicated that it had data to assess compliance during startup and shutdown, the EPA does not have any such data. The commenter misinterpre ted the EPA’s statement in the 2013 proposal preamble “Based on the information before the Agency, which includes information provided by industry, we expect facilities can meet the proposed emission standards during startup and shutdown.” (78 FR 22378) “T he information before the A gency” includes the two docket items EPA

- HQ

- OAR

- 1042

- 0334 and EPA

- HQ

- OAR

- 1042

- 0307, which provide adequate information to establish a recordkeeping requirement, but not to establish emission limits during periods of startup and shutdown.

45. Comment : One commenter (1041

- 0126) objected to the monitoring requirements for control devices during startup and shutdown, adding that sources may have to install new control devices in order to demonstrate compliance during periods of startup a nd shutdown, a requirement that the commenter considered cost

- prohibitive considering the emissions, while although unquantified, are likely negligible during this period of time. The commenter added that presumably some emissions may be higher during star tup and shutdown, but that EPA does not have data on which to base the requirement that the emissions limit should apply during these periods.

Response: No data were provided by the commenter in support of statements regarding the magnitude of emissions du ring startup and shutdown. While we agree that emissions during startup and shutdown are likely to be negligible, emissions during this time may not be excluded from regulation. As addressed elsewhere in the response to comments received on the November 25 , 2011 proposed RTR, recent court decisions have made clear that sources subject to MACT must comply with the limits in the rule at all times, and are not exempt from regulation due to startup, shutdown, or malfunction. Further, according to information submitted by all mineral wool manufacturers, all cupolas are currently equipped with controls that can meet the limits of the rule, and curing and collection processes only operate when fed melt from the cupola. Thus, no facilities would have to purchase and install new air pollution control devices to comply with the startup and shutdown provisions, as alleged by the commenter. Additionally, we disagree with the commenter that monitoring the control device parameters is burdensome: according to information c ollected during site visits, all manufacturing processes, operating parameters and production processes are already monitored and recorded by sophisticated computerized systems.

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In addition, we note that the commenter later filed an amended comment in a letter to EPA (EPA

- HQ

- OAR

- 2010

- 0142

- 0300) in support of the revised rule requirements for periods of startup and shutdown.

46. Comment: One commenter (1041

- 0126) expressed concerned that mineral wool facilities may be in violation of the rule because their co ntrol devices may not be as effective during startup and shutdown as they are during steady

- state normal production. While the commenter noted that EPA’s test methods are only used to measure emissions during steady

state operations, companies have not att empted to measure emissions that occur during startup and shutdown, and requested that EPA conduct further analyses to determine actual emissions during these periods, determine the best performing sources and evaluate whether they achieve the limits durin g startup and shutdown. The commenter also questioned whether the controls in use would achieve the same emissions reductions during startup and shutdown as they achieve during steady

- state operations.

Response: We considered the air pollution control devi ces in use in this industry to determine whether a properly operated fabric filter (baghouse), ESP, thermal oxidizer or RTO would achieve the same reduction in emissions regardless of loading, temperature of the process exhaust, and stability of the emissi ons stream. According to the information available to us on the mineral wool industry, the control devices used at mineral wool facilities achieve the same emission reduction regardless of changes in these parameters. For these reasons, we proposed and are finalizing the requirement that facilities must route emissions occurring during startup and shutdown to the control device operating at the parameters that showed compliance with the rule during the most recent performance test.

With regard to testing d uring startup and shutdown periods, emissions are not at steady state during startup and shutdown (a necessary factor for accurate emissions testing), and the varying stack conditions, gas compositions and low emission rates make accurate emission

measurem ents impracticable. In addition, the startup period for mineral wool cupolas is usually 2 hours, which is too short a time in which to conduct source testing.

Furthermore, as stated above, the commenter later filed an amended comment in a letter to EPA (EP A

- HQ

- OAR

- 2010

- 0142

- 0300) in support of the revised rule requirements for periods of startup and shutdown.

47. Comment: The commenter (1041

- 0126) requested changes to the proposed definitions for startup and shutdown, closed

- top cupolas, open

- top cupolas, and the three definitions for the curing and collection subcategories. The commenter also supported the proposed definition of the combined collection/curing process.

Response: We met with industry representatives on July 16 and July 25, 2013 to discuss these issues with both the existing facility representatives and with representatives of a new facility undergoing construction in Mississippi. Because the new facility is planning to construct process equipment meeting the applicability description of subpart D DD, but of a distinctly unique design, we are incorporating into the final rule requirements for startup and shutdown that are applicable to all mineral wool facilities. Specifically, these requirements will include compliance demonstrations for cupolas op erating in oxidizing conditions, with oxygen

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concentrations above 24 percent. These provisions provide a means for mineral wool production facilities to meet the limits of the rules at all times, including during periods of startup and shutdown, regardless of cupola design.

We also acknowledge the commenter’s support for the proposed definition of the “combined collection/curing” process. However, we disagree with the commenter’s suggestions regarding the definition of “closed

- top cupola” and “open

- top cup ola,” and with the need to include definitions for vertical, drum, and horizontal collection. Therefore, in the final amendments to the Mineral Wool NESHAP, we included the definition of “combined collection/curing,” as proposed.

48. Comment : Three commenters (1041

- 0073/1042

- 0111, 1042

- 0120, and 1041

- 080) stated that EPA should take malfunctions into account when adopting emission standards, adding that there is nothing in CAA section 112 that allows EPA to ignore malfunctions and set MACT standards based on a level of emissions that even best

- performing sources only achieve part of the time.

According to the commenters, the EPA’s rationale contravenes congressional intent that MACT floor standards be based on what the best sources actually achieve, and “account ing for malfunctions could lead to standards that are significantly less stringent than levels that are achieved by a well

- performing non

- malfunctioning source.” The commenters stated that the EPA acknowledges that even properly designed and operated equip ment will sometimes exceed emission limitations that were based on steady

- state operation, due to malfunctions, and emissions during such often are not routed to a stack where they can be measured, and upsets during stack testing invalidate the test result s under the EPA’s approved test methods. The commenters agreed with the EPA’s understanding that SSM events can lead to higher emissions even at well

- operated facilities with the best control equipment, but thought that should lead the EPA to prescribe alt ernative design, equipment, work practice or operational standards under its CAA section 112(h) authority (where it is not feasible to set or enforce a numerical emission limit). The commenters argued that the concept of “best performing” is inconsistent w ith a source experiencing a malfunction because it ignores that there are work practices

– such as monitoring operating parameters to identify a malfunction and stopping or cutting back the process accordingly

– that represent the best practices for minimi zing emissions during a malfunction. The commenters noted that while the measures that represent these best practices will depend on facility

- specific issues, such as process design, pollution control train, and other factors, they are nonetheless the “bes t technological system of continuous emission reduction ... adequately demonstrated.” The commenter claimed that “significant difficulties” are encountered by the proposed approach to malfunctions because even best

- performing sources, do not achieve the emis sion limit part of the time and since the EPA agrees they may be unavoidable or “not reasonably preventable,” despite proper design and maintenance of equipment, the commenter contended that there is no basis for the EPA’s conclusion that malfunction event s are not representative of best

- performing sources. By proposing MACT standards that the EPA recognizes even the best performing existing sources cannot achieve part of the time, the commenters argued that the EPA is going beyond the MACT floor without ma king the demonstrations that those conditions are reasonable “taking into consideration the cost of achieving such emission reduction.” See CAA section 112(d)(2).

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According to the commenters, the EPA does not present any substantiation for its belief that “[a]pplying the concept of ‘best controlled’ or ‘best performing’ to a unit that is malfunctioning presents significant difficulties” in setting CAA section 112 standards. See 76 Fed. Reg. at 72794 col. 3. The commenters argued that if the EPA acknowledge s that malfunctions are inevitable, even for the best performing sources, they should include emissions data representing malfunctions in calculating the MACT floor (see 76 Fed. Reg. at 72794 col. 3), and then require that those MACT floor limitations be m et even during malfunctions. However, the commenters also questioned whether it is possible to obtain emissions data during periods of malfunction.

The commenters contended that if it is possible to gather sufficient representative data reflecting emission s during malfunctions, then the EPA should consider such data in its MACT floor calculations for steady

- state operating conditions. The commenters added that, to the extent EPA had access to continuous monitoring data for emission units covered by the NESH AP, it should have conducted analyses of emissions levels during malfunction events. According to the commenters, many types of sources are required by many state agencies to submit deviation reports or malfunction reports when they experience a malfunctio n that causes an exceedance of an applicable limitation. The commenters argued that the EPA does 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 emiss ion units during malfunctions.

According to the commenters, there are several options the EPA could use for setting MACT standards under CAA section 112 that would apply during malfunction events, including establishing an emission limitation that applies at all times, but that has an averaging time of sufficient duration that short, infrequent spikes in emissions due to malfunctions would not cause the source to exceed the emission limit (while at the same time assuring that the source does not operate in a way that causes frequent, lengthy excursions above the normal controlled emission rate). The commenters noted that the EPA could also use the flexibility accorded by CAA section 302(k) (defining “emission limitation” and “emission standard” to include “a ny requirement relating to the operation or maintenance of a source to ensure continuous emission reduction, and any design, equipment, work practice or operational standard promulgated under” the CAA) to address emissions during malfunction events through operational requirements. The commenters added that the EPA might use a combination of such approaches for malfunction events.

Finally, if the EPA continues to conclude that it must eliminate the SSM exemption, the commenters stated that the limits are u nsupportable. Therefore, the EPA should instead adopt work practice standards, specifically to require that sources only operate existing pollution control equipment during startup and shutdown periods consistent with current practices, with exemptions for maintenance.

According to the commenters, because it is unclear whether the EPA considered these types of options, the proposed rule is arbitrary and the EPA should develop a new proposal.

Response: The EPA has provided a detailed justification for its approach to malfunctions in the preambles to the 2013 and 2014 proposals. There is nothing in CAA section 112 that directs the agency to consider malfunctions in determining the level “achieved” by the best performing sources when setting emission standards. As the D.C. Circuit has recognized, the

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phrase “average emissions limitation achieved by the best performing 12 percent of sources” says nothing about how the performance of the best units is to be calculated.” Nat'l Ass'n of Clean Water Agencies v. EPA , 734 F.3d 1115, 1141 (D.C. Cir. 2013). As discussed above, nothing in CAA section 112 requires the a gency to consider malfunctions as part of that analysis, accounting for malfunctions in setting emis sion standards would be difficult, if not impossible, and could lead to standards that are not reflective of levels achieved by a well

- performing non

malfunctioning source. As the D.C. Circuit also noted in Sierra Club v

. EPA , 167 F.3d 658 (D.C. Cir. 1999) , the phrase "average emissions limitation achieved by the best performing 12 percent of units” in section 112 of the CAA "says nothing about how the performance of the best units is to be calculated.” Id . at 661. Congress has not directly addressed the is sue of whether emissions that occur during periods of malfunction must be taken into account in calculating the performance of the best units and the EPA’s approach to malfunctions is reasonable for the reasons set out in the preamble to the proposed rule. For example, the EPA explained, and commenter agrees, that the factual complexity of differing processes and of the severity, frequency, and duration of malfunctions makes standard

- setting impracticable. In fact, the commenter’s statement that the best wo rk practices employed during malfunctions “will depend on facility

- specific issues, such as process design, pollution control train, and other factors” highlights the impracticability of setting work practice standards that apply across all sources in the category for the myriad types of malfunction that could occur. The commenter does not explain how any of the options suggested would make it any easier or practicable for the EPA to set a national standard that accounts for the innumerable types of malfunc tions that, as commenter points out, might vary depending on facility

- specific issues. The EPA further explained that the performance of units that are malfunctioning is not reasonably foreseeable and cited to case law supporting its approach to malfunctio ns. See Sierra Club at 665 (discussing need to take into account the worst reasonably foreseeable performance) and Weyerhaeuser v

. Costle , 590 F.2d 1011, 1058 (D.C. Cir. 1978) (“In the nature of things, no general limit, individual permit, or even any upse t provision can anticipate all upset situations.”).

In pointing out that “accounting for malfunctions could lead to standards that are significantly less stringent than levels that are achieved by a well

- performing non

malfunctioning source,” the EPA was m erely pointing out one possible consequence of taking malfunctions into account in setting standards if such an approach were practicable. This theoretical consequence is not driving the EPA’s approach to malfunctions. Further, the EPA’s is not going beyon d the MACT floor as the commenter suggests. Rather, the EPA is setting floor standards based on a reasonable interpretation of a statutory provision that is ambiguous as to how the performance of the best units is to be calculated.

The commenter argues tha t, if it is possible to gather sufficient representative data reflecting emissions during malfunctions, then the EPA is obligated to consider these data in its MACT floor calculations, but also makes the seemingly inconsistent point that it is often infeas ible to gather emission data during malfunctions.

With respect to commenters’ suggestion that the EPA consider work practice standards, section 112(h) of the CAA allows the EPA to set work practice standards instead of an emissions floor “if it is not fe asible in the judgment of the Administrator to prescribe or enforce an emission standard.” (“[T]he Administrator may , in lieu [of a numeric standard], promulgate a design, equipment, work practice, or operational standard, or combination thereof.”). In

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exe rcising the option to establish a work practice standard, that standard must “ in the Administrator’s judgment [be] consistent with the provisions of subsection (d) or (f).” CAA section 112(h)(1) (emphasis added). Under CAA section 112(h)(2)(B), it is “not feasible” to set an emission standard when “the application of measurement methodology to a particular class of sources is not practicable due to technological and economic limitations.” Thus, section 112(h) “allows EPA to substitute work practice standard s for emission floors only if measuring emission levels is technologically or economically infeasible.” Sierra Club v. EPA , 479 F.3d 875, 884 (D.C. Cir. 2007). These subsections make clear that the EPA is to base emission standards on the emission levels already achieved by the best performing sources as applicable. This means that work practice standards, although written in non

- numeric form, must still satisfy statutory requirements such as those applicable to MACT standards, including the requirement to be no less stringent than the MACT floor.

It is just as difficult to establish a work practice standard for malfunctions that can approximate the level of emission reduction achieved by the best performing sources during malfunctions as it would be to fac tor emission levels that occur during malfunctions into the numeric standards, as discussed above. The EPA would have to design a single work practice standard that applies equally to a tank explosion as it does to innumerable types of operator error,
comp uter glitches or a myriad of other unknown events, or alternatively create innumerable work practice standards.

In summary, the EPA believes that based on this rulemaking record it would be clearly inappropriate to set a work practice standard for malfunct ions in lieu of the otherwise applicable numerical emission limit. For all the reasons explained in the preamble to the final rule and above, the EPA’s approach to malfunctions is reasonable and consistent with the statute regardless of whether collection of certain types of malfunction data under certain circumstances is theoretically possible. We also note that we would consider any response to violations caused by a malfunction on a case

- by

- case basis through the exercise of enforcement discretion.

49. Com ment: One commenter (1041

- 0081) supported the EPA’s proposed removal of the startup, shutdown, and malfunction (SSM) exemption. The commenter asserted that D.C. Circuit struck down the SSM exemption as a violation of CAA section 112, 42 U.S.C. § 7412. All such exemptions are unlawful and must be removed.

Response: In the 2011 proposal, we explained that the D.C. Court had recently vacated the SSM exemption contained in 40 C.F.R. sections 63.6(f)(1) and 63.6(h)(1). Sierra Club v. EPA , 551 F.3d 1019 (D.C. Cir . 2008) cert. denied, 130 S. Ct 1735 (2010). The exemptions for startup and shutdown and for malfunctions in subpart DDD (Table 1 and 63.1180(d)) and NNN (Table 1) are inconsistent with the holding in Sierra Club that emissions limitations under CAA sectio n 112 must apply continuously. Thus, EPA is eliminating the SSM exemption in subpart DDD and NNN. The EPA has established work practice standards in this rule that apply during startup and shutdown periods.

50. Comment: One commenter (1041

- 0081) noted that the EPA should promulgate specific public reporting and notification requirements for malfunctions, or any e mission exceedance that occurs. According to the commenter, the EPA should require telephone reporting by the facility no later than 24 hours after the malfunction or exceedance, that such

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notice would be made publicly available on the EPA’s website and through ECHO within 24 hours, and that the Regional office must notify the local community on the Internet, by direct communication, and through all avai lable means.

In addition, the commenter argued that the EPA should promulgate the requirement that when such notification is made, the facility must also provide for community notification of the malfunction or emission standard exceedance within 24 hours, through an appropriate public forum that is designed to reach residents who live near the facility, including but not limited to a notice on the facility’s own website (if it has one), a written notice to the local municipality and local school district a nd a press release to the local newspaper, radio, and television news station that contains any information community members may need to try to protect themselves and their families from the additional air pollution. The commenter supported the EPA’s prop osal to require reporting of malfunctions, but prioritized this information so that the public can evaluate associated health risks.

According to the commenter, the EPA should also require a written report to be submitted within 7 days, and use the same di stribution method as outlined above, including publication on ECHO, the EPA’s Regional website, and sending this to active local community members who are interested (such as through setting up an email list, a local listserv, Twitter ®
, and other media).Th e commenter argued that, in the written report, the EPA should require the facility to report: (1) the nature of the event; (2) the duration of the event; (3) estimate of emissions released during the event; and (4) a description and timing of corrective a ctions that were taken and any planned to be taken.

The commenter contended that the reporting of malfunctions or other exceedances is not enough to protect the most exposed people from high metal and other HAP emissions like those from the Wool Fiberglass and Mineral Wool source categories. The commenter contended that the EPA also should promulgate additional requirements that apply in the event of a malfunction or violation of the numerical emission standards. According to the commenter, the CAA requires continuous compliance with the emission standards. The commenter provided the ECHO reports of a number of existing sources in the Wool Fiberglass source category for the EPA to consider as part of this rulemaking. The commenter stated that the EPA should take action to protect local communities from unacceptable risk. The commenter stated that facilities must not be able to emit in an unlimited manner for an unlimited period of time.

The commenter stated that, in addition to requiring reporting of exceedan ces and malfunctions, the EPA should:

1. Require automatic shut

- off of the malfunctioning equipment or process for the time needed to take corrective action whenever an exceedance or malfunction occurs.

2. Assign responsibility and liability to the plant manager or a senior staff member that allows only that person to restart the equipment or process.

3. Require specific corrective measures to be taken immediately to remedy and prevent recurrence of the malfunction or violation.

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The commenter also stated that, for a facility that has had one or more malfunction, exceedance, or other violation incident in the prior month, written authorization by EPA should be required to restart equipment or processes. The commenter further noted that EPA should only authorize restar t after making a public determination that provides information on the corrective measures that EPA is requiring. The commenter claimed that EPA should release this public determination on the Internet and require its Regional office to communicate this de termination to all interested members of the public, including local community representatives. If a facility has more than 4 exceedances or malfunctions during the same quarter, the commenter urged EPA to require automatic shut down of the operation for a period of time needed to conduct and publish a full investigation and ensure systematic correction of the problems.

The commenter further claimed that the EPA should create a community complaint mechanism in the standards that ensures that citizen complai nts of clouds, plumes, exceedances, odors, other air pollution incidents or health concerns receive an immediate response, in which EPA commits to initiate an investigation and provide a publicly available report of the result of the investigation, includi ng whether it leads to an enforcement outcome from EPA’s enforcement division within 7 days.

Response: The final rule requires malfunction recordkeeping and reporting, including for each failure to meet a standard, the date, time, and duration, a list of t he affected sources or equipment, an estimate of the volume of each regulated pollutant emitted over the standard, a description of the method used to estimate such emissions, and actions taken to minimize emissions and any corrective actions taken. Any re ports submitted to the EPA are publicly available subject to the requirements of CAA section 114(c). We do not agree with the commenter that the suggested additional notification and reporting requirements are necessary, as they would be duplicative of the immediate notification requirements of the Superfund Amendments and Reauthorization Act ( SARA ) / Comprehensive Environmental Response, Compensation, and Liability Act ( CERCLA ) / Emergency Planning and Community Right

- to

Know Act ( EPCRA ) , would be burdensome f or both facilities and agencies to review, and would not enhance compliance beyond that of the requirements in the rule for reporting violations of emission limits.

E. Authority to Fill Data Gaps in Existing MACT Standards

51. Comment: One commenter (1041

- 0081) s tated that the EPA should set a standard to limit all HAP emissions. The commenter pointed out that the EPA’s dataset for both source categories includes mercury emissions that are currently uncontrolled by the standards. T he commenter argued that the EPA has failed to propose a limit to control these emissions. According to the commenter, CAA section 112 requires the EPA to set an emission standard to control all HAP emitted at all times. The commenter stated that the EPA s hould do so, at least by setting the mercury limit at the detection level if emissions fall below that.

The commenter was also concerned that, because the furnaces in this source category use a combustion process, the source category may emit dioxin. The c ommenter contended that the EPA has not addressed dioxin and that it is unclear whether the EPA required testing for dioxin.

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The commenter urged the EPA to ensure that it sets a limit on dioxin if these source categories emit this pollutant.

Response: In t he 1999 NESHAP, we established emissions limits for many HAP that were emitted from processes under both the Mineral Wool Production and the Wool Fiberglass Manufacturing source categories, and we are amending those standards with emission limits for HAP t hat are emitted from the sources and which can be measured and controlled using existing air pollution control technology.

At this time we are not setting limits for mercury under this rulemaking. We do not believe that the limited data we have at this time is sufficient to set a mercury emissions limit. Regarding dioxin, the EPA had no information suggesting that dioxin was expected to be emitted from sources in either of these industries, and no information indicated that conditions conducive for dioxi n formation were present in these source categories. In light of this, we did not require emission testing for dioxin from sources in these industries. Consequently, we did not propose emission limits for dioxin. Additionally, no information was brought to us during any of the three comment periods upon which we could base emission limits for dioxin, and no information was brought forth that would lead us to reconsider this decision. Therefore, the final emission limits for these industries do not include e mission limits for dioxin

.

F. Monitoring, R ecordkeeping and R eporting

52. Comment: One commenter (1041

- 0081) urged the EPA to strengthen enforcement, monitoring, and reporting requirements for these source categories. According to the commenter, EPA should take this action both under CAA section 112(f)(2) and under CAA section 112(d)(6). The commenter also stated that, considering that the risk from the Wool Fiberglass source category has disproportionate effects on minority and economically disadvantaged communi ties, additional monitoring and stronger enforcement provisions would help provide environmental justice, especially in Kansas City.

Response: We believe that the monitoring requirements included in these rules are sufficient to ensure compliance with the standards regardless of whether or when a violation occurs. Under the provisions of 40 CFR 63.15, the public can request access to reports submitted to the regulatory agency whenever they choose, with the exception of information protected through 40 CFR part 2 (e.g., CBI ). In addition, as discussed below, we are promulgating requirements for electronic reporting of emissions test data that will improve public access to emissions information.

53. Comment: One commenter (1041

- 0081) asserted that the EPA should require periodic testing that will assure compliance and demonstrate to the EPA, states, and the public whether or not the facilities are in compliance. The commenter added that the EPA should write standards that ensure prompt compliance, pursuant to the deadlines set by the Act. Section 112 of the CAA includes strict compliance provisions for residual risk standards and all other CAA section 112(d) standards. The commenter contended that the EPA also must ensure that strict monitoring and enforcement pro visions are part of its standards to enforce the permit condition requirements of the Act. The commenter noted that the CAA requires permits to contain ―conditions as are necessary to assure compliance with applicable requirements of [the Act]. 40

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C.F.R. P art 70 adds detail to this requirement. 40 C.F.R. § 70.6(a)(3) requires ―monitoring sufficient to yield reliable data from the relevant time period that are representative of the source’s compliance. The commenter noted that section 70.6(c)(1) requires all Part 70 permits to contain testing, monitoring, reporting, and recordkeeping requirements sufficient to assure compliance with the terms and conditions of the permit. The commenter suggested that the EPA should fully review the monitoring requirements it has proposed and ensure that they are sufficient to quickly determine the compliance status of a facility. The commenter further stated that the EPA should require performance tests every year instead of every 5 years to stay up

- to

date on the industry’s e missions and compliance status.

Response: We believe that the monitoring requirements included in these rules are sufficient to ensure compliance with the standards. With regard to the frequency of performance tests, we agree that there are many instances in which annual performance tests can be used as a tool by which the citizens can be informed of the emissions of HAP from particular industrial sources. We also are concerned with the impact to regulated entities that annual testing imposes. Performance tests can interrupt production and manufacturing at a facility, and can be costly; we are therefore mindful to temper imposing the frequency of testing with the hazard that may be assessed by release of a highly toxic pollutant. Based on information from i ndustry, we found that both formaldehyde and chromium compounds are highly toxic HAP emitted from wool fiberglass facilities. We anticipate in general that formaldehyde emissions from bonded lines at wool fiberglass facilities will continue to decline, but that chromium emissions from the furnaces will both continue and may increase rapidly and unexpectedly. We therefore are requiring annual testing at wool fiberglass gas

- fired furnaces for chromium emissions. For the PM, formaldehyde, methanol and phenol e mission limits for wool fiberglass facilities, the final rule requires performance testing initially and every 5 years. We are also requiring owners or operators of mineral wool facilities to conduct performance tests initially and every 5 years.

54. Comment : One commenter (1041

- 0081) supported the EPA’s proposal for electronic reporting because it will strengthen EPA, state, and citizen enforcement, and provide prompt information transparency for local communities near facilities. The commenter stated that b ecause the public has a right to all reports collected under the CAA, it is important that the EPA ensure immediate disclosure of these reports within 7 days of receipt and without necessitating a FOIA request.

Response : We appreciate the commenter’s support for requiring electronic reporting in the NESHAP and GACT standards. However, we disagree with the commenter that reports submitted electronically should be available to the public within 7 days of receipt. In our
pro posed revisions to certain New Source Performance Standards (NSPS) regulations to require electronic reporting (80 FR 15100) and our anticipated revisions to certain part 63 NESHAP , we are proposing that electronic reports submitted to the Compliance and E missions Data Reporting Interface (CEDRI) be stored on the EPA’s Central Data Exchange (CDX) for 60 days before they will be available for public access. During this 60

- day processing period, the report will be available to the EPA or registered air agency personnel to conduct a quality review of the report data and supporting documentation and the report preparer may submit corrections to the report to CEDRI based on the air agency’s review. We believe that this processing period is necessary to ensure tha t the data available to the public are as complete and accurate as possible and we do

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not agree with the commenter that a 7

- day period is sufficient for the air agency to review the submissions.

55. Comment : One commenter ( 1041

- 0081 ) stated that the EPA should require continuous monitoring of emissions from this source category. The commenter noted there is technology available to perform continuous emissions monitoring for Hg, HCl, HF, PM, and opacity, among others, and asked the EPA to require the use of this technology to assure compliance, adding that the EPA should require immediate Internet reporting of all monitoring records.

Response : We disagree with the commenter that continuous emissions monitoring systems (CEMS) are necessary for ensuring compliance with the final emission limits for PM and chromium. The final standards require that owners or operators conduct performance tests initially and annually thereafter to demonstrate compliance with the chromium emission limit. For PM, owners or operators mu st conduct performance tests initially and every 5 years to demonstrate compliance with the final emissions limits. We believe that the performance testing schedule specified in the final rule is appropriate for demonstrating compliance with the chromium a nd PM emission limits.

We also disagree with the commenter that the EPA should require CEMS for HCl and HF emissions from furnaces. As noted in our April 2013 notice, we proposed work practice standards for HF and HCl emissions because the test data showed that for at least 80 percent of the furnaces tested, emissions were lower than the detection level of the methods used to measure those pollutants. Section 112(h) of the CAA allows the EPA to set work practice standards instead of an emissions floor “if i t is not feasible in the judgment of the Administrator to prescribe or enforce an emission standard.” Under CAA section 112(h)(2)(B), it is “not feasible” to set an emission standard when “the application of measurement methodology to a particular class of sources is not practicable due to technological and economic limitations.” Thus, CAA section 112(h) “allows EPA to substitute work practice standards for emission floors only if measuring emission levels is technologically or economically infeasible.” Sie rra Club v. EPA , 479 F.3d 875, 884 (D.C. Cir. 2007). Because we identified technological and economic limitations associated with measuring HF and HCl emissions from furnaces, the EPA has the discretion to adopt work practice standards rather than establis hing numeric emission limits.

The final rule also requires owners or operators to ensure that the cullet fed to gas

- fired glass

- melting furnaces does not contain glass from the following chloride

- , fluoride

- , or fluorine

bearing components that would form HF or HCl in the furnace exhaust: glass from industrial (also known as continuous strand, or textile) fiberglass, cathode ray tubes (CRT), computer monitors that include CRT, and glass from microwave ovens, televisions or other electronics. ensure their cu llet feedstock does not contain any of these chloride

- , fluoride

- , or fluorine

bearing components by one of two approaches: (1) Require the providers of external cullet to verify that the cullet does not include waste glass from the chloride

- , fluoride

- or fluorine

bearing components, or (2) Sample their raw materials to show the cullet entering the furnace does not contain glass from these components. To demonstrate compliance, the final rule requires facilities to maintain quality assurance records for ra w materials and/or records of glass formulations indicating the facility does not process fluoride

- , fluorine

- , or chloride

- bearing materials in their furnaces, and that they thereby maintain low HF and HCl emissions. The final

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rule also requires facilitie s to record the percentage of cullet in the materials mix fed to the furnace during the performance t est and to maintain the rolling 30

- day average cullet percentage at or below the level established during the test these types of sources either by conduct ing their own internal inspection and recordkeeping program, or by receiving certification from their cullet suppliers. Given the low level of emissions and the monitoring and recordkeeping requirements of the final rule, we do not believe that CEMS are wa rranted for HCl and HF emissions from gas

- fired glass

- melting furnaces.

G. G eneral A pproach T o C alculating MACT

56. Comment: One commenter (1042

- 0120/1041

- 0080) argued that the EPA can revise an existing standard only under CAA section 112(d)(6) because the NRDC v. EPA decision (HON RTR rule: Cf. NRDC v. EPA

, 529 F.3d 1077, 1084 (D.C. Cir. 2008)) plainly holds that the EPA is not required to “correct” prior MACT standards or recalculate MACT standards under CAA section 112(d)(6).

Response: We disagree with the comment. The commenter mischaracterizes the HON decision, which involved RTR revisions to existing and properly promulgated MACT standards. CAA section 112(d)(6) provides that the agency must review and revise “as necessary.” The “as

n ecessary” language must be read in the context of the provision, which focuses on the review of developments that have occurred since the time of the original promulgation of the MACT standard and thus, should not be read as a mandate to correct flaws that existed at the time of the original promulgation. Further , the D.C. Circuit has held that the EPA may permissibly amend improper MACT determinations, including amendments to improperly promulgated floor determinations, using its authority under CAA sectio ns 112 (d)(2) and (3). Medical Waste Institute v. EPA , 645 F.3d 420, 425

- 27 (D.C. Cir. 2011). (Resetting MACT floor, based on post

compliance data, permissible when originally

- established floor was improperly established, and permissibility of the EPA’s ac tion does not turn on whether the prior standard was remanded or vacated). Similarly, Portland Cement Ass’n v. EPA , 665 F.3d 177, 189 (D.C. Cir. 2011) confirms th at CAA section 112 (d)(6) does not constrain EPA and it may reassess its standards more often, including revising existing floors if need be.

As also previously explained, in several recent rulemakings, we have chosen to fix underlying defects in existing MACT standards under CAA sections 112(d)(2) and (3), provisions that directly govern the initi al promulgation of MACT standards (see National Emission Standards for Hazardous Air Pollutants From Petroleum Refineries, October 28, 2009, 74 FR 55670; and National Emission Standards for Hazardous Air Pollutants: Group I Polymers and Resins; Marine Tank Vessel Loading Operations; Pharmaceuticals Production; and the Printing and Publishing Industry, April 21, 2011, 76 FR 22566). We believe that our approach is reasonable because using those provisions ensures that the process and considerations are those associated with initially establishing a MACT standard, and it is reasonable to make corrections following the process that would have been followed if we had not made an error at the time of the original promulgation.

57. Comment: One commenter (1042

- 0120/10 41

- 0088/1041

- 0126) disagreed with the EPA’s interpretation of the CAA that the lowest performing sources are representative of the actual performance of the best performing sources. The commenter argued that the EPA is not

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constrained by the Brick MACT to interpret “best controlled similar source” to mean “those with the lowest emission levels” because this Brick MACT language is an isolated statement and does not necessarily underpin the Brick MACT decision, is not supported by any other D.C. Circuit decis ion, and is contradicted by the technology approach endorsed by the courts for the Portland Cement and National Lime MACT standards . According to the commenter, Congress did not intend, and the courts have never required that the EPA equate the “lowest emi tting” sources to the “best performing” sources and that the EPA is not required to set emission standards equivalent to the level achieved by the lowest emitting sources. 19

The commenter argued that in its review of the 1999 Portland Cement MACT Standards

, the court endorsed a “technology approach” to setting the MACT standards, whereby the EPA would use the relative performance of air pollution control technology to select the best performing sources. 20

The commenter quoted the D.C. circuit:

“ According to the Sierra Club, section 7412(d)(3) requires EPA to set new source floors at the lowest recorded emission level for which it has data and existing source floors at the average of the lowest twelve percent of recorded emission levels for which it has data. Nothing in the statute, the Sierra Club argues, permits the Agency to set floors based on the performance of technology as opposed to the recorded performance of plants.

In resolving this issue, we do not write on a clean slate. EPA’s technology

- based
appr oach to setting new source emission standards has already faced and survived a Chevron one challenge. In Sierra, 334 U.S. App. D.C. 421, 167 F.3d 658, we reviewed a new source emission standard for solid waste combustion that EPA promulgated pursuant
to se ction 7429, which establishes emission requirements virtually identical to that of section 7412. There, as here, the Sierra Club argued that EPA’s MACT technology approach to setting emission standards is unambiguously forbidden by the CAA . Sierra rejected that argument, holding that EPA may estimate the performance of the best performing units and that it was not “impossible” that EPA’s methodology constituted a reasonable estimation technique. See 167 F.3d at 665.” [ National Lime Ass’n v. EPA , 233 F.3d 62 5, 631 (D.C. Cir. 2000).]”

The commenter concluded that the D.C. Circuit in National Lime endorsed the EPA’s use of a technology

- based approach that uses the relative performance of pollution control technology to set the MACT floor.

The commenter observed that the EPA’s decisions to equate best performance with lowest emissions, rather than with other means of measuring performance, is based on a parenthetical phrase found in the Brick MACT decision that refers to the “best performing” sources as “those wi th the lowest emission levels.” The commenter stated that this isolated statement is dictum; it is not a necessary underpinning of the Brick MACT decision, nor is it

19 See Sierra Club v. EPA , 167 F.3d 658, 661 (D.C. Cir. 1999) ( CAA section 112(d) “on its own says nothing about how the performance of the best units is to be calculated”).

20 National Lime Ass’n v. EPA , 233 F.3d 625, 631 (D.C. Cir. 2000).

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supported by any other D.C. Circuit decision on this issue. The commenter argued that in B rick MACT , the D.C. Circuit affirmed its decision in Cement Kiln that the EPA cannot redefine “best performing” to mean those sources with emission levels achievable by all sources:

“But EPA cannot circumvent Cement Kiln’s holding that section 7412(d)(3) requires floors based on the emission level actually achieved by the best performers (those with the lowest emission levels), not the emission level achievable by all sources.”

The commenter stated that the EPA’s interpreta tion of this dictum is to prohibit the adoption of any measure of “best performing” other than lowest emission levels, but this is an unnecessarily narrow view of the language of Brick MACT . The commenter asserted that the Brick MACT decision did not overrule either of the National Lime or Sierra decisions, in which the D.C. Circuit approved approaches that did not simply equate “best performing” sources with “those with the lowest emission levels.” According to the commenter, the EPA responded to the demonstrably contradictory yet binding precedent by electing to follow non

- binding language that would appear to place great restraint on the EPA’s discretion. The commenter questioned why the EPA is willing to sacrifice its discretion on this issue when it has repeatedly asserted its discretion to characterize “best performing” sources by criteria other than simply the lowest emission level.

The commenter asserted that there is no reason to read the Brick MACT language the way the EPA doe s for purposes of the Proposed Rule when there is an alternative interpretation

– relative performance of sources and control technology

– that harmonizes Brick MACT with prior and still binding case law.

The commenter observed that the EPA’s interpretatio n of Brick MACT collides with CAA section 112(d)(3) and other D.C. Circuit decisions requiring the EPA to take non

technological and non

- intentional factors into consideration if they impact emissions levels achieved in practice by sources, particularly as the EPA is advocating a “pollutant

- by

- pollutant” approach to setting the MACT floor. The commenter maintained that the EPA has the discretion to address factors such as technologies that lower a particular HAP but increase emissions of another air polluta nt, and not be constrained to identify the lowest emitters of that particular HAP as the best performing sources regardless of any collateral negative impacts.

The commenter noted that the EPA has, since the Brick MACT decision, acknowledged its discretio n to define “best performing” sources in a manner that accounts for all the relevant factors. The commenter noted that in its Notice of the Proposed Hazardous Waste Combustor (“HWC”) Reconsideration Rule, the EPA justified using control efficiency rather t han the simplistic emissions levels in defining “best controlled” and “best performing” HCl production furnaces, and although the final HWC rule hews to the narrow view of the Brick MACT decision, the commenter quoted the EPA that, “standards requiring HAP reduction of a given percent limit the emission quantity, rate, and (in any realistic scenario) concentration of the HAP and so falls squarely within the statutory definition [of emission standard].”

The commenter maintained that NESHAP standards must ‘co nsider emissions in the best performing sources as they would be under the worst foreseeable circumstances’ per instruction

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in Sierra Club v. EPA , 167 F.3d 658, 665 (D.C. Cir. 1999). The commenter suggests that the EPA should use this consideration as one basis to increase the EPA’s emissions estimate of the performance of the sources defining the MACT floor, thereby raising the proposed emission limits, which the commenter believes is appropriate.

Response: S ection 112(d) of the CAA requires the EPA to pro mulgate standards for major sources of HAP that are based on MACT performance. For existing sources, MACT standards must be at least as stringent as the average emissions limitation achieved by the best performing 12 percent of existing sources (for which the Administrator has emissions information) or the best performing 5 sources for source categories with less than 30 sources. For new sources, the MACT standards must be at least as stringent as the control level achieved in practice by the best controlle d similar source. In construing CAA section 112(d)(3), the D.C. Circuit has stated that “[t]hough section 7412(d)(2) does direct the EPA to require the maximum emission reduction that it determines to be achievable, section 7412(d)(3) provides that the

max imum degree of reduction in emissions that is deemed achievable. . . shall not be less stringent that what the best

- performing sources achieve. Section 112(d)(3) therefore limits the scope of achievable in section 7412(d)(2).” Sierra Club v. EPA , 479 F.3d at 878. (Internal quotations omitted). The Court has also stated that “to comply with the statute, the EPA’s method of setting emissions floors must reasonably estimate the performance of the best performing plants.” Sierra Club v. EPA , 167 F.3d at 665. As also previously explained, the D.C. Circuit has consistently rejected the EPA’s reading of “achieved by the best performers,” in section 112(d)(3), as meaning achievable by all sources within a source category. “EPA’s rationales . . . amount to nothing mo re than concern about ensuring that its floor is achievable by all kilns in the subcategory

-- precisely the position we rejected in Cement Kiln.” Sierra Club v. EPA , 479 F.3d at 881. See also, Cement Kiln v. EPA , 255 F.3d at 861 “EPA may not deviate from se ction 7413(d)(3)’s requirement that floors reflect what the best performers actually achieve by claiming that floors must be achievable by all sources using MACT technology.”

With regard to the comment that the EPA justified using control efficiency rathe r than the simplistic emissions levels in defining “best controlled” and “best performing," in more recent rulemakings, the EPA has not proposed an alternative standard expressed as a percent reduction reflecting the average of the best removal efficiencie s. We have reasoned that one problem with a percent reduction standard is that it could downplay the role of HAP inputs on emissions by allowing more HAP to be emitted provided a given level of removal efficiency reflecting the average of best removal effi ciencies is achieved. We have also explained that we believe percent reduction standards are not legally permissible because the Brick MACT opinion states, arguably in dicta, that best performers are those emitting the least HAP (see 479 F. 3d at 880 (“sec tion [112 (d)(3)] requires floors based on emission levels actually achieved by best performers (those with the lowest emission levels)”). More important, the opinion stresses that raw material inputs must be accounted for in determining MACT floors. Id . a t 882

- 83.

Thus, while the Brick MACT decision did not overrule either National Lime or Cement Kiln , it did reiterate prior holdings and again invalidated our prior reading of section 112(d)(3) as allowing factors other than the performance of the best per forming sources in our MACT floor calculations. More recently, in Portland Cement Ass’n v. EPA , 665 F.3d 177, 189 (D.C. Cir. 2011), the Court stated “PCA also argues EPA violated the CAA when it premised the NESHAP standards on bare emissions data rather than on data that specifically isolated the effect of

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technology by controlling for variations in input quality. We considered and rejected this very argument quite recently” in Sierra Club . (“We declined to read the Clean Air Act’s command that it assess the emission ‘control’ or ‘limitation’ achieved [as] refer[ring] to the deliberate steps kiln o perators take to reduce emissions rather than to the ‘happenstance’ of being located near cleaner clay.” Id . at 189. (Alterations in original)).

As explained earlier, CAA section 112(d)(3), does not address the question of whether, in assessing which sour ces perform best or are best controlled, emission levels should be evaluated either over time or in a single test result. We believe, however, that our MACT floor calculation should identify the best performers (i.e., the best performing 12 percent or best performing five sources in smaller source categories for existing sources, and the best controlled single source for new sources), as those sources likely to emit the least HAP over time considering variability. In other words, the EPA does not believe th at the statute requires or contemplates a random sample. Rather, use of data from the best performing sources is specified for developing the MACT floor limits. The EPA also believes that the lowest emission value available from a given source is a reliabl e measure of the best performance the source has achieved. We use the lowest emission value to rank the different facilities and to select the best performing sources. We do not use the average because it is affected by extreme values, both large and small , and does not represent the best performance of the source. We believe that use of the lowest emissions value is consistent with the D.C. Circuit construct of CAA sections 112(d)(2) and (d)(3).

Thus, in calculating the MACT floor for each pollutant for th e two source categories, we used the lowest emission value to rank the different facilities and to select the best performing sources. We did not assign unusually low emissions to any unit. We also used all the available emission data from all best perform ing sources to estimate the variability in the UPL, as discussed in the preamble to the 2011 proposal and the memorandum “Use of the Upper Prediction Limit for Calculating MACT Floors” (available in the docket for this action), accounting for within and be tween source variability. Additionally, where a dataset consisted of limited data, we used a UPL approach based on limited datasets, as discussed in more detail in the preamble to the 2014 proposal. We obtained the available data from emissions tests that the commenter submitted in accordance with the voluntary survey it conducted of wool fiberglass manufacturing facilities and from the CAA section 114 survey conducted to collect data for all furnaces not represented by the voluntary survey, in support of t he 2013 proposal. As explained in the November 2011 proposal, industry conducted a voluntary survey that called for test data for HAP emissions and process equipment and processes. In lieu of testing, the EPA also allowed for submittal of prior existing an d well documented test data that were representative of wool fiberglass manufacturing operations. 76 FR 72778. In certain instances, industry opted to submit existing test data in lieu of conducting new testing. (“ EPA typically has wide latitude in determi ning the extent of data

- gathering necessary to solve a problem. We generally defer to an agency's decision to proceed on the basis of imperfect scientific information, rather than to invest the resources to conduct the perfect study. ” Sierra Club v. EPA , 3 34 U.S. App. D.C. 421, 167 F.3d 658, 662 (D.C. Cir. 1999) (citation omitted) )

. Thus, the limits being finalized are based on data representing all existing wool fiberglass manufacturing facilities and mineral wool production facilities, and we disagree wit h the comment’s assertion that EPA’s dataset for each of these two source categories is a “very small data set, collected during a specific time period, and without any historical data.” We conducted outlier analyses of these datasets and do not believe th at the data in the resultant MACT floor pool data sets are outlier data. Thus, contrary to

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the commenter’s assertions, we have also identified the best performers for each source category for purposes of the MACT floor calculation in the memoranda “Revised MACT Floor Analyses for Wool Fiberglass Manufacturing Source Category” and “Revised MACT Floor Analyses for Mineral Wool Production Source Category,” both of which are in the docket for this rulemaking.

Further, because the D.C. Circuit has held repeated ly that variability of best performing sources may be taken into account in establishing MACT floors. Sierra Club , 479 F.3d at 881

- 882, ( See also National Lime Ass’n v. EPA , 627 F.2d 416, 431 n.46, 443(D.C. Cir. 1980)), we believe it is appropriate to cons ider statistical variability in order to ensure that units could meet the floors at all times.

As noted earlier, we are prohibited from setting floors on the level that can simply be achieved by all sources; the MACT floor emission limit must be set at the level achieved by the average of the best 12 percent of existing sources (and may consider variability); new source MACT must be the limit achieved by the best controlled similar source.

58. Comment: One commenter (1041

- 0080/1041

- 0126/1042

- 0120) suggested t hat the EPA did not adequately take variability into account in its MACT floor determinations for the mineral wool production and wool fiberglass manufacturing source categories.

According to the commenter, the EPA has historically demonstrated persuasive ly why the

a gency might in its discretion choose some other or more complex measure of what constitutes a “best performing” source. The data that the EPA collected for the wool fiber glass manufacturing industry and the mineral wool production industry ind icate such an approach

– which accounts for operational and other variability that undermines any straightforward connection between the “lowest emitters” and the “best performing” sources

– would be justified.

The commenter stated that the D.C. Circuit h as held that NESHAP must consider emissions in the best performing sources as they would be “under the worst foreseeable circumstances.” To evaluate the emission limits achieved by existing sources, the commenter noted that the EPA is required to develop m ethodologies for estimating the variability associated with all factors that impact a source’s emissions, including process, operational and non

technological variables. The commenter asserted that these factors may change on a frequent basis in relation t o price fluctuations and availability, such as fuel type, or may only change slowly over time, such as by operational decisions regarding waste management and product specifications. While courts have affirmed the EPA’s authority to choose a methodology de signed to estimate emissions in setting the MACT floor, the commenter noted that the courts have also made clear that the EPA’s method “must ‘allow a reasonable inference as to the performance of the top 12 percent of units.’” Accordingly, the commenter no ted that the Court of Appeals for the D.C. Circuit has stated that “EPA must show not only that it believes its methodology provides an accurate picture of the relevant sources’ actual performance, but also why its methodology yields the required estimate. ” ( Sierra Club v. EPA , 167 F.3d at 663; DC Circuit 1999)

The commenter stated that the EPA has a clear policy of considering long

- term variability when establishing enforceable emission rates for both Prevention of Significant Deterioration (PSD) permits u nder the CAA and Best Available Control Technology (BACT)

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emissions limits. The commenter asserted that the Environmental Appeals Board has recognized the use of “safety factor[s]” in the calculation of BACT permit limits to take into account both the vari ability and fluctuation in the expected performance of pollution controls and the fact that setting emissions limitations for one facility at the highest control efficiency demonstrated at another facility would make violations of the permit unavoidable. F or this reason, the commenter argued that the policy and common sense approach used by the EPA in PSD permitting should also apply in establishing MACT standards.

The commenter contended that the EPA should not rely solely on short

- term data from similar s ources and ignore the variability and long

- term impact of the proposed emission rates. The commenter stated that the EPA has expressed caution regarding reliance on stack test and short

- term emissions data results to derive a MACT floor due to the variabil ity in operating conditions at any facility. In the EPA’s proposed rule to set a NESHAP for mercury at coal

- fired electric utilities, the commenter noted that the a gency identified a number of factors that contribute to the variability in emission test dat a that must be considered, including the ( 1) emission test method; ( 2) analytical method; ( 3) design of the unit and the control device(s); ( 4) operating conditions of the facility and the control device(s); ( 5) amount of constituent being tested in the fu el; and 6) composition of the constituents in the fuel or flue gases. The commenter stated that the EPA should consider these sorts of factors in this rulemaking.

Furthermore, the commenter argued that this policy and common sense approach is recognized an d required by the D.C. Circuit. Once the “similar sources” category is established, the EPA should identify the lowest emission limitation that has been “achieved in practice” by these sources. In another MACT case, the commenter cited that the D.C. Circui t has held that the phrase “achieved in practice” refers to the performance of the source “under the wor st foreseeable circumstances.” ( Sierra Club , 167 F.3d at 664. )

The commenter contended that the EPA should follow its own common sense approach and the directive of the D.C. Circuit and develop MACT standards that consider the long

- term emission variations in mineral wool and wool fiberglass facilities. Specifically, the commenter argued that HCl and HF emissions data are limited to the BTEC data collecte d during a single season, and there are no historic data. The commenter asserted that mineral wool companies are concerned that given the limitations of the data, consistent compliance with the EPA’s proposed limits will be difficult. Therefore, the commen ter urged the EPA to apply liberal variation factors to account for the limitation of the HCl and HF data.

Response: S ection 112(d)(3) of the CAA requires that the MACT standards for existing sources be no less stringent than the average emission limitatio n achieved by the best performing 12 percent of existing sources for which the EPA has emissions information. “Section 112(d)(3) requires floors that are based on the emission level actually achieved by the best performers (those with the lowest emission l evels).” Sierra Club , 479 F.3d at 880. As we have explained in various rules, CAA section 112(d)(3) does not address the question of whether emission levels should be evaluated either over time or in a single test result for assessing which sources perform best or are best controlled. We believe, however, that our MACT floor calculation should identify the best performers (i.e., the best performing 12 percent or best performing five sources in smaller source categories for existing sources, and the best controlled single source for new sources) as those sources likely to emit the least H AP over time considering variability. Further,

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the D.C. Circuit has held repeatedly that variability of best performing sources may be taken into account in establishing MACT floors. Id at 881

- 882. See also National Lime Ass’n v. EPA , 627 F.2d 416, 431 n.4 6, 443(D.C. Cir. 1980). Therefore, we believe it is appropriate to consider statistical variability to ensure that regulated sources can meet the proposed limits at all times.

Further, as explained in earlier responses, the EPA believes that the UPL calcul ation is a valid statistical approach to estimate a MACT floor level (including variability) that is equivalent to the average of the best performing sources based on future compliance tests. The EPA believes it is entirely appropriate to consider the vari ability within the best performing sources in developing emission limits based on the average performance of those sources. We also believe that if we did not account for variability in this manner, and instead set the limit based solely on the average (me an) performance (e.g., as measured by a single test at each source), then it would be reasonable to expect these same units to exceed the limit half the time or more. The EPA agrees with the commenter that there are alternatives to the UPL statistics. But, we believe that because the floor calculations represent the average of the best performing 12 percent of existing sources, it is reasonable for the EPA to use an appropriate statistical analysis to assess the effect that both intra

- unit and inter

- unit va riability have on the emissions profiles.

Consistent with CAA sections 112(d)(2) and (3), the MACT floors for both source categories were calculated using the UPL approach, which includes variability based on the individual test runs from the top five per forming sources for which we have data. We have also revised and updated our calculation of the proposed limits for both source categories using additional test data we received in response to the proposed rules, including new data and data corrections fro m the wool fiberglass and mineral wool industries and they are based on all certified or independently

- verifiable emission stack test data of appropriate quality available to the EPA. As a result, we have revised the appropriate limits in the final rule. O ur calculations and detailed explanations can be found in the memoranda, Use of the Upper Prediction Limit for Calculating MACT Floors,” and “Approach for Applying the Upper Predicti on Limit to Limited Datasets,” which are available in the dockets for this rulemaking.

Further, as explained in the 2011 proposal, the EPA and industry, as documented in the trade association’s (NAIMA’s) April 13, 2010 letter, agreed on the sources and emissions testing that would be conducted for these rules using the EPA appro ved test methods. In that letter, industry assured the EPA that these tests would provide data that would be representative of other mineral wool producers across the U.S. In acknowledging this agreement, the April 13, 2010 letter indicated that the bases for representativeness would include design type and size of process units or equipment, fuel type, operating temperatures, control devices and raw material content. We note that all mineral wool producers participated in this process and agreed with the

v oluntary data collection effort initiated by the trade association. The industry conducted these emissions tests during 2010, submitted them to the EPA in January 2011 and submitted new information regarding cupola design and raw material use after the pro posed rules were published in November 2011 and in April 2013. (“ EPA typically has wide latitude in determining the extent of data

- gathering necessary to solve a problem. We generally defer to an agency's decision to proceed on the basis of imperfect scien tific information, rather than to invest the resources to conduct the perfect study. ” Sierra Club v. EPA , 334 U.S. App. D.C. 421, 167 F.3d 658, 662 (D.C. Cir. 1999) (citation omitted) )

.

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59. Comment: One commenter (1042

- 0120/1042

- 0348/1041

- 0126) stated the prop osed standards for the mineral wool production and wool fiberglass manufacturing source categories are based on pollutant

- by

- pollutant analyses that rely on different sets of best performing sources for each HAP standard. The commenter maintained that the EPA has “cherry

- picked” the best performing data in setting each standard, without regard for the sources from which the data originated. The commenter stated that the result is a set of standards that reflect the performance of a hypothetical set of best performing sources that simultaneously achieve the greatest emission reductions for each HAP, rather than the actual performance of one or more real sources. The commenter asserted that this biased approach is contrary to the language of section 112 of the CAA and produces unrealistic and impracticable standards.

The commenter (1042

- 0120/1042

- 0348) argued that the statute unambiguously directs the EPA to set standards based on the overall performance of sources. The commenter observed that sections 112(d)(1 ), (2), and (3) of the CAA specify that emissions standards must be established based on the performance of “sources” in the category or subcategory and that the EPA’s discretion in setting standards for such units is limited to distinguishing among classe s, types, and sizes of sources. The commenter pointed out that these provisions make clear that standards must be based on actual sources, and cannot be the product of pollutant

- by

- pollutant parsing. The commenter noted that Congress also provided express limits on the EPA’s authority to parse units and sources for purposes of setting standards and that express authority does not allow the EPA to “distinguish” units and sources by individual pollutant as it has proposed in this rule.

The commenter (1042

- 012 0/1042

- 0348) observed that in other MACT standards, the EPA has taken the position that the cherry

- picking argument was waived if not raised in the original promulgation of the MACT. The commenter argued that in the original wool fiberglass MACT, the EPA o nly directly regulated one pollutant per affected facility

– PM for furnaces and formaldehyde for forming, collection, and curing lines (either RS or FA ). The commenter concluded that the EPA did not engage in “cherry

- picking” in the original MACT rule and neither the commenter nor the industry had the need to raise the issue in the original 1999 rulemaking.

Response: The EPA disagrees with the commenter. Contrary to the commenter’s suggestion, CAA section 112(d)(3) does not mandate a total facility approach. A reasonable interpretation of CAA section 112(d)(3) is that MACT floors may be established on a HAP

- by

HAP basis, so that there can be different pools of best performers for each HAP. Indeed, as illustrated below, the total facility approach is not compelled by the statutory language but can lead to results so arbitrary that the approach may simply not be legally permissible.

S ection 112(d)(3) of the CAA is ambiguous as to whether the MACT floor is to be based on the performance of an entire sour ce or on the performance achieved in controlling particular HAP. Congress specified in CAA section 112(d)(3) the minimum level of emission reduction that could satisfy the requirement to adopt MACT. For new sources, this floor level is to be “the emission control that is achieved in practice by the best controlled similar source.” For existing sources, the floor level is to be “the average emission limitation achieved by the best performing 12 percent of the existing sources” for categories and subcategorie s with 30 or more sources, or “the average emission limitation achieved by the best performing 5 sources” for categories and

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subcategories with fewer than 30 sources. The language of the CAA does not address whether floor levels can be established HAP

- by

- H AP or by any other means. The reference to “sources” does not lead to the assumption the commenter makes that the best performing sources can only be the best

- performing sources for the entire suite of regulated HAP. Instead, the language can be reasonably interpreted as referring to the source as a whole or to performance as to a particular HAP. Similarly, the reference in the new source MACT floor provision to “emission control achieved by the best controlled similar source” can mean emission control as t o a particular HAP or emission control achieved by a source as a whole.

Also, CAA section 112(d) includes language such as “existing source,” “best performing,” and “achieved in practice” in referring to sources’ actual operations, but again the language s ays nothing about whether it is referring to performance as to individual HAP or to single facility’s performance for all HAP. Industry commenters also said that Congress could have mandated a HAP

- by

- HAP result. The argument that MACT floors set HAP

- by

- HAP are based on the performance of a hypothetical facility, so that the limitations are not based on those achieved in practice, just re

- begs the question of whether CAA section 112(d)(3) refers to whole facilities or individual HAP. All of the limitations i n the floors in this rule of course reflect sources’ actual performance and were achieved in practice.

The commenter also points to EPA’s subcategorization authority, and claims that because Congress authorized the EPA to distinguish among classes, types, and sizes of units, the EPA cannot distinguish units by individual pollutant, as they allege the EPA did in the proposed rules. However, that statutory language addresses the EPA’s authority to subcategorize sources within a source category prior to setti ng standards. In doing so, the EPA does not distinguish within each subcategory based on HAP emitted. Rather, it establishes emissions standards based on the emissions limits achieved by units in each subcategory. Therefore, the EPA’s subcategorization
aut hority is irrelevant to the question of how the EPA establishes MACT floor standards once it has made the decision to distinguish among sources and create subcategories.

The EPA’s long

- standing interpretation of the CAA is that the existing and new source MACT floors are to be established on a HAP

- by

- HAP basis. One reason for this interpretation is that a whole plant approach could yield least common denominator floors

– that is floors reflecting mediocre or no control, rather than performance which is the average of what best performers have achieved. See 61 FR 173687 (April 19, 1996); 62 FR 48363

- 64 (September 15, 1997) (same approach adopted under the very similar language of CAA section 129 (a)(2)). Such an approach would allow the performance of sources that are outside of the best

- performing 12 percent for certain pollutants to be included in the floor calculations for those same pollutants, and it is even conceivable that the worst performing source for a pollutant could be considered a best performer overall, a result Congress could not have intended. Inclusion of units that are outside of the best performing 12 percent for particular pollutants would lead to emission limits that do not meet the requirements of the statute.

For example, if the best per forming 12 percent of facilities for HAP metals were also the worst performing units for acid gas HAP, the floor for acid gases or metals would end up not reflecting best performance. In such a situation, the EPA would have to make some type of value judgm ent as to which pollutant reductions are most critical to decide which sources are best

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controlled. Such value judgments are antithetical to the direction of the statute at the MACT floor

- setting stage.

The central purpose of the amended air toxics provis ions was to apply strict technology

based emission controls on HAP. See, e.g., H. Rep. No. 952, 101st Cong. 2d sess. 338. The floor’s specific purpose was to assure that consideration of economic and other impacts not be used to “gut the standards. Althoug h costs are by no means irrelevant, they should by no means be the determining factors. There needs to be a minimum degree of control in relation to the control technologies that have already been attained by the best existing sources.” A Legislative Histo ry of the Clean Air Act, Vol. II at 2897 (statement of Rep. Collins). An interpretation that the floor level of control must be limited by the performance of devices that only control some of these pollutants effectively “guts the standards” by including w orse performers in the averaging process, whereas the EPA’s interpretation promotes the evident Congressional objective of having the floor reflect the average performance of best performing sources. Because Congress has not spoken to the precise question at issue and the a gency’s interpretation effectuates statutory goals and policies in a reasonable manner, its interpretation must be upheld. See Chevron v. NRDC , 467 U.S. 837 (1984).

The EPA notes, however, that if optimized performance for different HAP is not technologically possible due to mutually inconsistent control technologies (for example, if metals performance decreased if organics reduction is optimized), then this would have to be taken into account by the EPA in establishing a floor (or floors ). The Senate Report indicates that if certain types of otherwise needed controls are mutually exclusive, the EPA is to optimize the part of the standard providing the most environmental protection. S. Rep. No. 228, 101st Cong. 1st sess. 168 (although, as noted, the bill accompanying this Report contained no floor provisions). It should be emphasized, however, that, “the fact that no plant has been shown to be able to meet all of the limitations does not demonstrate that all the limitations are not achievab le.” Chemical Manufacturers Association v. EPA , 885 F.2d at 264 (upholding technology

- based standards based on best performance for each pollutant by different plants, where at least one plant met each of the limitations but no single plant met all of them ).

Finally, we note that the D.C. Circuit recently found a challenge to the a gency’s practice of setting floors based on emissions levels achieved by the best performing units on a pollutant

by

- pollutant basis to be barred on jurisdictional grounds. Medica l Waste Institute v. EPA , 645 F.3d 420 (D.C. Cir. 2011).

60. Comment: One commenter (1042

- 0115f) stated that the EPA has the duty under the MACT Review, CAA section 112(d)(6), both to look back and to have reductions now achievable and to look around at develo pments in the technology processes and work practices to update the rule to obtain all appropriate emission reductions.

Response: We agree with the commenter, and note that the final rule addresses technology review for these source categories. Specificall y, the EPA conducted a technology review on the wool fiberglass MACT to determine what emission limits are appropriate due to improvements in technology and work practices that have developed since the MACT standard was promulgated in 1999. We determined t hat there are developments in practices, processes, and control technologies that warrant revisions to the MACT standards for the Wool Fiberglass

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Manufacturing source category. Therefore, to satisfy the requirements of CAA section 112(d)(6), we are revisin g the existing MACT standards to include an emission limit for glass

- melting furnaces of 0.33 pounds of PM per ton of glass pulled as we proposed in April 2013. In this action, we are also revising the proposed chromium emission limit for gas

- fired glass

- m elting furnaces from 6.0E

- 05 to 2.5E

- 04 pounds of total chromium per ton of glass pulled, based on our

re

- assessment of emissions data for newly

- rebuilt gas

- fired glass

- melting furnaces. As explained in the preamble to the final rule, we have adopted both standards, under CAA sections 112(f)(2) and 112(d)(6), but these standards rest on independent statutory authorities and independent rationales. Consequently, these standards remain independent and legally severable

.

We a lso reviewed but did not find new developments in technology within the mineral wool production industry, and therefore we are readopting the existing PM standards under CAA section 112(d)( 6)

.

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V. MINERAL WOOL PRODUCT ION (SUBPART DDD)

A. Cupola PM Limits

61. Comme nt: One commenter (1041

- 0081) supported the EPA’s retention of particulate matter (PM) as a surrogate for HAP metals and the PM emission limit for mineral wool production. As noted by the EPA, the commenter stated that the courts have held that PM is
an ap propriate surrogate for HAP metals. Therefore, the commenter agreed that the EPA is correct in retaining PM as a surrogate for the Mineral Wool MACT.

Response: The a gency acknowledges the commenter’s support.

B. Cupola HF and HCl Limits

62. Comment: One commente r (1041

- 0164) supported the EPA's proposed emission limits for HF and HCl for existing sources in both cupola subcategories published on November 13, 2014.

Response: The a gency acknowledges the commenter’s support.

63. Comment: One commenter (1041

- 0080/1041

- 01 26) asserted that the EPA did not provide complete disclosure of the way the emission limits proposed in 2011 and 2013 were determined, including the specific data that the EPA did and did not consider in developing the limits. The commenter argued that th e EPA’s MACT floor calculation method for new and existing sources was improperly applied. The commenter argued that the EPA’s discussion in the preambles to the 2011 and 2013 proposed rules and the MACT floor memorandum lacked any details on the analysis itself. The commenter opined that, due to the insufficient detail regarding the data that the EPA did and did not consider, the EPA record is inadequate and, according to the commenter, subject to challenge. The commenter provided as an example, to determi ne UPL, the EPA should conduct statistical analysis related to the normality of the test data and possibly transform the data to produce a suitable distribution. The commenter noted that the MACT floor memorandum discusses this, but does not fully explain how the analysis was done for the mineral wool industry, which the commenter found to be a significant lapse. The commenter asserted that the EPA has a legal obligation under the CAA to include in the record a “statement of basis and purpose” that should i nclude such information. The commenter maintained that its absence violates s ection 307(d)(3) of the CAA, and, if not corrected prior to promulgation, would render the final rule arbitrary.

Response: We note that, in another letter (1041

- 0164), the commen ter subsequently expressed support for the HCl and HF limits for existing sources that we proposed in 2014 and are finalizing in this action (see comment number 6 2 ). We disagree with this comment and we believe that we clearly presented the data sources an d our approach used to calculate the MACT floors. In our November 25, 2011 proposal, we included a detailed explanation of our calculation of the MACT floors in the MACT Floor Analysis for the Mineral Wool Production Manufacturing Source Category memorandu m that is available in the docket for this rulemaking (docket item number EPA

- HQ

- OAR

- 2010

- 1041

- 0019). As explained in the 2011 proposal, we received test data from all the mineral wool production facilities in response to a voluntary survey conducted by th e commenter of both the mineral wool and wool fiberglass manufacturing

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facilities. The EPA requested from the commenter, and the commenter agreed (see the May 5, 2010 letter contained as Appendix A to docket item number EPA

- HQ

- OAR

- 2010

- 1041

- 0080), that the data submitted in response to the voluntary survey would include existing test data and test data collected from a subset of facilities that were representative of emission sources from certain mineral wool production facilities. In acknowledging this agr eement, the commenter’s May 5, 2010 letter indicated that the bases for representativeness would include design type and size of process units or equipment, fuel type, operating temperatures, control devices and raw material content. We also explained in t he November 25, 2011 preamble (76 FR 72778) that these responses included test data for most HAP metals, CO, PM, formaldehyde, methanol, and phenol emissions from cupolas, curing ovens and collection operations. We relied on these test data in calculating the MACT floor level of control for cupolas used in mineral wool production for the 2011 proposal.

In the April 15, 2013 supplemental proposal to the RTR (78 FR 22385) and in the memorandum “ Technical Approach for Mineral Wool MACT Floor Calculations ” (doc ket item number EPA

- HQ

- OAR

- 2010

- 1041

- 0109), we presented our rationale for developing subcategories for different types of cupolas and for revising the HF and HCl emission limits using the UPL approach. Additionally, more recently in the November 13, 2014 supplemental proposal (79 FR 68019) and in the memorandum “ Revised Technical Approach for Mineral Wool MACT Floor Calculations” (docket item number EPA

- HQ

- OAR

- 2010

- 1041

- 0156), we subsequently proposed and discussed our decision to revise the HF and HCl emi ssions limits for cupolas based on our updated approach for evaluating limited data sets (also see the memorandum “ Approach for Applying the Upper Prediction Limit to Limited Datasets

– Ferroalloys ” (docket item number EPA

- HQ

- OAR

- 2010

- 1041

- 0129) for the up dated approach for limited datasets).

64. Comment: One commenter (1041

- 0126) suggested in response to the 2013 proposal that one alternative approach for the EPA to use in developing the MACT floor limits for the acid gases HF and HCl from the two subcategorie s of cupolas (those that process slag and those that do not) is to set work practice standards instead of emission limits for HF and HCl for the subcategory of cupolas not processing slag.

Response: We note that, in another letter (1041

- 0164), the commente r subsequently expressed support for the HCl and HF limits for existing sources that we proposed in 2014 and are finalizing in this action (see comment number 6 2 ). We disagree with the commenter’s recommended alternative approach because it is unsupported by available test data and therefore, impermissible under the CAA. As explained in our 2011 and 2013 proposals, under CAA section 112(d), the EPA is required to promulgate standards for major sources of HAP based on MACT performance. For existing sources, MACT standards must be at least as stringent as the average emissions limitation achieved by the best performing 12 percent of existing sources (for which the Administrator has emissions information) or the best performing 5 sources for source categories w ith less than 30 sources. For new sources, the MACT standards must be at least as stringent as the control level achieved in practice by the best controlled similar source (section 112(d)(3)). The EPA is not allowed to consider costs in establishing the MA CT floor standards; “Congress imposed minimum stringency requirements

- the EPA calls them ‘emission floors’

- which apply without regard to either costs or other factors and methods listed in section 7412(d)(2).” Sierra Club , 479 F.3d at 877. The EPA also must consider more stringent “beyond

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the

- floor” control options. In doing so, the EPA must take into consideration the costs of achieving such options, and any non

- air quality health and environmental impacts and energy requirements ( CAA section 112(d)(2))

. Section 112(h) of the CAA allows the EPA to set work practice standards instead of an emissions floor “if it is not feasible in the judgment of the Administrator to prescribe or enforce an emission standard.” Under CAA section 112(h)(2)(B), it is “not feasible” to set an emission standard when “the application of measurement methodology to a particular class of sources is not practicable due to technological and economic limitations.” Thus, CAA section 112(h) “allows EPA to substitute work practice standards for emission floors only if measuring emission levels is technologically or economically infeasible.” Sierra Club v. EPA , 479 F.3d 875, 884 (D.C. Cir. 2007). Because we did not identify any t echnological or economic limitations associated with measuring HF and HCl emissions from cupolas, the EPA does not have the discretion to adopt work practice standards rather than establishing emission limits.

65. Comment : One commenter (1041

- 0080/1041

- 0126) s tated that their understanding was that the proposed MACT standards for HF and HCl for existing sources were calculated by taking the average of the top five cupolas and multiplying it by different multipliers

– possibly 2, 2.5, or 3. The commenter noted t hat current calculations of the EPA’s proposed emission limits seem to average out as follows:

• COS

– 3 times the Top 5 Cupola Average

• HF

– 1.5 times the average of the top five cupolas

• HCl

– 1.5 times average of the top five cupolas

Pollutant Emission Li mit (lb/ton of melt)

Average of Top 5 Cupolas EPA’s Proposed Rule Multiplied Average by 3 for COS and 1.5 for HF and HCl Multiplied Average by 2 Multiplied Average by 2.5 Multiplied Average by 3 99% UPL Existing Sourc es

COS 1.066979 3.30 2.1338 2.667 3.2007

HF 0.008895 0.014 0.01778 0.0222 0.02669

HCl 0.0066 0.0096 0.01316 0.0165 0.0198

The commenter urged the EPA to use a higher multiplier, where possible, for all pollutants to account for greater variability in emission limits.

Response : We note that this commenter subsequently expressed support for the finalized HCl and HF limits for existing sources, as summarized in comment number 6 2

. Regarding the commenter’s understanding of the EPA’s MACT floor calculations and the EPA’s use of multipliers, as explained in the 2011 proposal (6 FR 72788), the 2013 supplemental proposal (78 FR 22385

- 22386), and the 2014 supplemental proposal (79 FR 680 17

- 68018, and 68109), we

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used the UPL approach our updated approach to evaluated limited datasets to develop the HF and HCl emissions limits, rather than multipliers as noted by the commenter.

66. Comment: One c ommenter (1041

- 0080/1041

- 0126) argued that the EP A is not required to set limits for HCl and HF. The commenter (1041

- 0080) stated that the EPA is not required to regulate HCl and HF because, as the EPA acknowledged, HCl and HF were not regulated under the 1999 Mineral Wool MACT Standard and the emissions of these pollutants have not increased in the mineral wool industry since that time. The commenter added that the industry has experienced a significant reduction in the number of operating plants since implementation of the MACT standard. The commenter a rgued that because of the EPA's interpretation of the Brick MACT decision, the EPA believes that the court decision mandates imposition of emission limits for HCl and HF.

The commenter stated that the EPA’s interpretation is incorrect, and that the a gency is not mandated to regulate HCl and HF. The commenter noted that the amount of HCl and HF emitted by mineral wool sources does not meet the 10 tons per year threshold required to trigger MACT applicability. Moreover, the commenter stated that the EPA can r evise an existing MACT standard only under CAA section 112(d)(6). The commenter claimed that the NRDC v. EPA decision (HON RTR rule) plainly holds that the EPA is not required to “correct” prior MACT standards or recalculate MACT standards under CAA sectio n 112(d)(6). Therefore, the commenter asserted

, the EPA does not need to regulate HCl and HF. But if it decides to do so, the commenter contended that the EPA does not need to set a standard under CAA sections 112(d)(2) and (d)(3).

The commenter (1041

- 0126 ) opined that precedent exists in the CAA section 112 MACT standard for utility boilers to support the premise that the EPA is not required to set emission limits for all HAP emitted from a source category. The commenter observed that for coal

- fired utilit ies, the EPA has published AP

- 42 emission factors indicating that organic HAP are emitted from these sources, but the EPA has not regulated organic HAP emissions either directly or by using a surrogate. The commenter requested that the EPA refrain from set ting any standard for HF and HCl from mineral wool production processes on the basis of this example from the coal

fired utility industry.

Response: We disagree with the comment er that CAA section 112(d)(6) is the EPA’s sole authority for revising existing MACT standards. We believe that CAA section 112 does not expressly address this issue, and that the EPA has discretion in determining how to address potential revisions to a promulgated standard. CAA section 112(d)(6) provides that the agency must review and revise “as necessary.” The “as necessary” language must be read in the context of the provision, which focuses on the review of developments that have occurred since the time of the original promulgation of the MACT standard and thus, should not be rea d as a mandate to correct flaws that existed at the time of the original promulgation. Further, recent D.C. Circuit’s decisions support the EPA amending improper MACT determinations under CAA sections 112 (d)(2) and (3). The D.C. Circuit held that the EPA may permissibly amend improper MACT determinations, including amendments to improperly promulgated floor determinations, using its authority under CAA sections 112(d)(2) and (3). Id . Thus, we believe that we may amend improper MACT determinations, includin g amendments to improperly promulgated floor determinations, under CAA sections 112 (d)(2) and (3). Medical Waste Institute v. EPA , 645

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F.3d 420, 425

- 27 (D.C. Cir. 2011) (resetting MACT floor, based on post

- compliance data, is permissible when originally

- e stablished floor was improperly established, and permissibility of the EPA’s action does not turn on whether the prior standard was remanded or vacated). Here, the EPA did not establish a MACT standard for these HAP, an approach soundly rejected by the D.C . Circuit in National Lime , 233 F.3d at 633

- 34. We also note that, i n National Lime Association v. EPA , 233 F.3d 625 (D.C. Cir. 2000), the D.C. Circuit remanded the Portland Cement MACT to the EPA to establish MACT floors for HCl holding that we had a clea r “statutory obligation to set emission standards for each listed HAP.” Therefore, we believe the EPA is not barred from making MACT floor determinations and issuing MACT standards pursuant to CAA sections 112(d)(2) and (3) for this source category. Additi onally, in several recent rulemakings, we have chosen to fix underlying defects in existing MACT standards under CAA sections 112(d)(2) and (3), the provisions that directly govern the initial promulgation of MACT standards (see National Emission Standards for Hazardous Air Pollutants From Petroleum Refineries, October 28, 2009, 74 FR 55670; and National Emission Standards for Hazardous Air Pollutants: Group I Polymers and Resins; Marine Tank Vessel Loading Operations; Pharmaceuticals Production; and the Pr inting and Publishing Industry, April 21, 2011, 76 FR 22566). We believe that our approach is reasonable because using those provisions ensures that the process and considerations are those associated with initially establishing a MACT standard, and it is reasonable to make corrections following the process that would have been followed if we had not made an error at the time of the original promulgation.

We also disagree with the comment that the EPA did not regulate (directly or by surrogate) any organic HAP from coal

- fired utilities in the recent Utility MACT rule. To the contrary, the EPA established work practice standards for organic HAP under CAA section 112(h). Additionally, in the Boilers NESHAP we established a MACT standard for HCl emissions. Both HCl and HF are listed HAP under CAA section 112(b), and we are statutorily required to establish MACT standards for all HAP emitted by major sources under CAA section s 112(d)(2) and (3).

67. Comment: One commenter (1014

- 0164) opposed the emission limits for H F and HCl for new sources in both cupola subcategories proposed on November 13, 2014. The commenter argued that the proposed limits were very stringent and impossible to meet with existing technology available to the industry, and would prohibit expansion or growth of the mineral wool industry. The commenter argued that the proposed new source emission limits are based on very limited a dataset resulting in too much uncertainty (a large standard deviation) and an unacceptably high MACT floor. The commenter argued that historical data are lacking because mineral wool facilities have not been regulated for HF and HCl emissions. The commenter asked that the EPA delay HF and HCl emission limits for new sources until the next residual risk analysis when more data are available.

The commenter (1041

- 0088/1041

- 0126) expressed a similar concern in response to the HF and HCl emission limits for new and existing sources proposed on November 25, 2011, and April 15, 2013, saying that these limits were based on a very smal l data set collected in a brief period of time and in one season of the year, and that these data failed to correctly account for variation in emissions over time (e.g., season to season or over the course of the year). The commenter added that there has b een no indication that HCl and HF emissions from industry have increased since the 1999 NESHAP was finalized. To address this lack of data and unknown

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variability, the commenter requested that the EPA recalculate the proposed limits using data in a way tha t maximizes variability, such as calculating emission limits based on the best performing sources rather the lowest emitting sources. In their comment on the 2014 proposal (1041

- 0164), the commenter expressed support for the EPA's method for addressing dat a variability and limited data availability by calculating emission HF and HCl limits using the UPL approach.

In addition to considering variability in the emissions data, the commenter emphasized that the EPA should also consider variability in the proces sing rate. Given the fact that EPA is using lbs per ton of melt data to calculate the MACT floor, the commenter believed that variability in that processing rate is equally important.

Response: Regarding the comment that the EPA should delay finalizing HF and HCl emission limits, the EPA is finalizing emission limits for HF and HCl proposed in 2014 to meet the EPA’s statutory obligation to set emission standards for each listed HAP, as reinforced by the court’s decision in National Lime v. EPA (233 F.3d 625, 634 (DC Cir. 2000)) (see the 2011 proposed rule (76 FR 72788)). Congress specified in CAA section 112(d)(3) the minimum level of emission reduction that could satisfy the requirement to adopt MACT. For new sources, this floor level is “the emission control that is achieved in practice by the best controlled similar source.” Thus, CAA section 112(d)(3) requires the EPA to establish the MACT floor for new sources differently for new sources and e xisting sources and the EPA is prohibited from adopting the same standard for new sources as for existing sources, as recommended by the commenter, where the available data indicate that new sources can achieve a more stringent level of control, which is t he case here. As such, the EPA may not set limits for new sources equal to the limits for existing sources because the available data indicates that new sources can achieve “the emission control that is achieved in practice by the best controlled similar s ource.”

The EPA’s analysis of the available data indicate that the proposed limits for new sources were based on the emission controls that are achiev ed by the best controlled similar source, as discussed in the preamble to the 2014 proposed rule (79 FR 68 020) and in the supporting memorandum in the docket for this rulemaking (EPA docket item EPA

- HQ

- OAR

- 2010

- 1041

- 0156).

In response to the comment that the EPA’s dataset for HCl and HF is too limited and does not include historical data, as explained in the 2 011 proposal, industry conducted a voluntary survey among all owners and operators of mineral wool production facilities to collect HCl and HF data. Further, the EPA requested and industry agreed (see the May 5, 2010 letter contained as Appendix A to docke t item number EPA

- HQ

- OAR

- 2010

- 1041

- 0080), that a subset of facilities that were representative of emission sources from both the mineral wool and wool fiberglass industries would conduct emissions testing. The April 13, 2010 letter indicated that the bases for representativeness included design type and size of process units or equipment, fuel type, operating temperatures, control devices and raw material content. With regard to HCl and HF emissions data, the letter states that “[f]ive of the six companies are collecting new data. The Thermafiber data is representative of Amerrock Products based on the following: all of the cupolas are coke

- fired, melting blast furnace slag and producing slag wool products.” In lieu of new testing, the EPA also allowed indus try to submit prior existing and well

- documented test data that were representative of wool fiberglass manufacturing operations (76 FR 72778). In certain instances, industry opted to submit existing test data in lieu of conducting new testing.

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(“ EPA typica lly has wide latitude in determining the extent of data

- gathering necessary to solve a problem. We generally defer to an agency's decision to proceed on the basis of imperfect scientific information, rather than to invest the resources to conduct the perfe ct study. ” Sierra Club v. EPA , 334 U.S. App. D.C. 421, 167 F.3d 658, 662 (D.C. Cir. 1999) (citation omitted) )

. Thus, we disagree with the commenter’s assertion that the EPA’s data set is a very small, collected during a specific time period, and without hi storical data.

Further, regarding the comment that the EPA’s dataset failed to correctly account for variations in processing and emissions over time, the D.C. Circuit has held repeatedly that variability of best performing sources may be taken into acco unt in establishing numeric MACT floors. See Mossville Environmental Action Now v. EPA , 370 F.3d 1232, 1241

- 42 (D.C. Cir. 2004). Section 112(d)(3) of the CAA “requires that floors reflect a reasonable estimate of the emissions achieved in practice by the b est

- performing sources.” Cement Kiln Recycling Coalition v. EPA , 255 F.3d 855, 872

- 73 (D.C. Cir. 2001) (internal quotes omitted); See also, Sierra Club v. EPA , 479 F.3d at 881

- 82. Consistent with section 112(d)(2) and (3), the MACT floors for HCl and HF we re calculated using the UPL approach, which includes variability based on the individual test runs from the best performing 12 percent of sources

– or in this case, the top 5 performing sources. A more detailed explanation of how we calculated the MACT flo ors can be found in the “Technical Approach for Mineral Wool MACT Floor Calculations” (September 15, 2011) 21 and in the two memoranda updating this 2011 analysis, “Technical Approach for Mineral Wool MACT Floor Calculations” (February 7, 2013), 22 and “ Revise d Technical Approach for Mineral Wool Production MACT Floor Calculations (September 26, 2014) .” 23

Regarding the commenter’s request that the EPA address data limitations and variability by calculating emission limits based on the “best performing sources” rather the “lowest emitting sources,” the EPA uses the lowest emission value to rank the different facilities and to select the best performing sources (see the EPA’s response to comment number 5 7 for a detailed EPA response to this comment).

The EPA appr eciates the commenter’s support for its use of the UPL approach in the 2014 proposal.

68. Comment: One commenter (1041

- 0080; 1041

- 0126) stated that the EPA’s calculation of the MACT floor for the HCl and HF emission limits proposed on November 25, 2011 was flawed because the EPA erred in selecting and analyzing the data used in the MACT analysis. The commenter argued that, in selecting the top five performing sources (the Mineral Wool Source Category has less than 30 sources), the EPA calculated the MACT floor for HCl and HF with data from two facilities that are synthetic area sources. The commenter argued that the MACT floor can be based only on data from sources in the source category being regulate d. The commenter noted that there are no reported legal decisions supporting the use of synthetic area sources in setting MACT floors under CAA section 112(d)(3), and the commenter challenged and objected to using synthetic area sources for this MACT deter mination. The

21 EPA docket item number EPA

- HQ

- OAR

- 2010

- 1041

- 0019.

22 EPA docket item number EPA

- HQ

- OAR

- 2010

- 1041

- 0109.

23 EPA docket item number EPA

- HQ

- OAR

- 2010

- 1041

- 0156.

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commenter argued that only major sources compose the source category, so only major sources should be included in the MACT floor. The commenter noted that true area sources are not included in MACT floor determinations, and concluded that syn thetic area sources should be treated similarly. The commenter argued that including synthetic area sources would lead to controls that would be both technologically and economically infeasible, especially for specific plants. The commenter argued that thi s could lead to a result in which the "MACT floor" meeting the criteria in CAA section 112(d)(3) would be rejected if the criteria in CAA section 112(d)(2) were applied. 24 The commenter urged the EPA to reconsider the sources it selected to create the MACT floor.

Response: We disagree with the commenter’s assertion that test data for the two synthetic area sources may not be used to establish the MACT floor for major sources, as well as the commenter’s suggestion that the EPA should exclude these data, becau se such an exclusion would be impermissible under the CAA. As explained in previous rulemakings ( e.g., Brick NESHAP, 68 FR 26697

– 26698, May 16, 2003), the EPA has determined that including synthetic area sources in calculating the MACT floor for major sour ces is consistent with CAA section 112(d). We continue to believe that inclusion of synthetic area sources in MACT floor determinations is justified for the reasons explained below. Section 112 of the CAA does not specifically address the inclusion of synt hetic area sources in the MACT floor calculations. These are sources that emit fewer than 10 tons per year of any HAP or fewer than 25 tons per year of any combination of HAP because they use some emission control device(s), pollution prevention techniques or other measures (collectively referred to as controls in this document ) adopted under Federal or State regulations. If not for the enforceable controls they have implemented, synthetic area sources would be major sources under section 112 of the CAA. We believe that the better interpretation of the CAA's plain language and legislative history requires that synthetic area sources be included in MACT floor determinations.

First, the plain language of the statute makes clear that our MACT floor determinati ons are to reflect the best sources in a category. For new sources in a category or subcategory, the MACT floor shall not be less stringent than the emission control that is achieved in practice by the best

- controlled similar source, as determined by the E PA. Section 112(d)(3) of the CAA requires that MACT floors reflect what the best controlled new sources and the best performing existing sources achieve in practice. These phrases contain no exemptions and are not limited by references to sources with or w ithout controls. Therefore, they suggest that all of the best

controlled or best

- performing sources should be considered in MACT floor determinations, regardless of whether or not such sources rely upon controls.

Second, CAA section 112(d)(3) expressly exc ludes certain sources that meet LAER requirements from MACT floor determinations for existing sources. (See CAA section 112(d)(3)(A).) The fact that Congress expressly excluded such LAER sources but did not also exclude synthetic area sources suggests that no exclusion was intended for synthetic area sources. Indeed, nothing in the statute suggests that EPA should exclude a control technology from its consideration of the MACT floor because the technology is so effective that it reduces source emissions suc h that the source is no longer a major source of HAP.

24 The commenter c ited Sierra Club v. EPA , 479 F.3d 875, 884, and 885.

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Third, the EPA disagrees that the CAA contemplates that synthetic area sources must be treated like true area sources and excluded from MACT floor determinations. Section 112(a) of the CAA defines a ma jor source as: any stationary source or group of stationary sources located within a contiguous area and under common control that emits or has the potential to emit considering controls, in the aggregate, 10 tons per year or more of any hazardous air poll utant or 25 tons per year or more of any combination of hazardous air pollutants * * * (See CAA section 112(a)(1).) An area source is defined as any stationary source of hazardous air pollutants that is not a major source. (See CAA section 112(a)(1).) In th e major source definition, the reference to a source's potential to emit considering controls allows the interpretation that a source's potential to emit before and after controls is relevant, such that synthetic area sources may be considered within the m eaning of this definition and included in MACT floor determinations for categories of major sources. This is because w e believe synthetic area sources, because they have already reduced HAP emissions below the major source threshold, they are among the bes t performing 12 percent of existing sources and thus help to define the level of the MACT emission limit. Thus, i ncluding synthetic area sources in MACT floor determinations ensures that MACT floors reflect the best

- performing sources, as the CAA requires. While the effect of excluding the best performing sources in a category from MACT floor determinations and therefore would be contrary to the statutory mandate that the EPA set MACT floors based on the levels the best controlled new sources and the best p erforming existing sources achieve in practice. We believe the statutory reference to potential to emit considering controls should be read in a manner consistent with the other requirements of section 112(d) of the CAA to allow for the consideration of sy nthetic area sources in MACT floor determinations for categories of major

sources.
Fourth, relevant legislative history for this section suggests that synthetic area sources should be included in MACT floor determinations. In a floor statement, Senator Du renberger stated that in implementing section 112(d)(3) of the CAA, "the [Senate] managers intend the Administrator to take whatever steps are necessary to assure that [the Administrator] has collected data on all of the better

- performing sources within ea ch category. [The Administrator] must have a data

- gathering program sufficient to assure that [EPA] does not miss any sources that have superior levels of emission control." (See Environment and Natural Resources Policy Division, Congressional Research Ser vice, 103d Cong., S.Prt. 103

- 38 (prepared for the U.S. Senate Committee on Environment and Public Works), A Legislative History of the Clean Air Act Amendments of 1990 at 870, Nov. 1993, emphasis added.) This statement underscores that Congress intended for MACT floor determinations to reflect consideration of all of the sources in each category with the best emission controls. We believe it would be inconsistent with Congress's intent and the plain language of the CAA to exclude synthetic area sources

- those sources with superior controls which became synthetic area sources by implementing such controls

- from MACT floor determinations. Therefore, we believe that the inclusion of synthetic

a rea sources in MACT floor determinations is justified because of the reasons explained above.

The EPA Title V Operating Permits Program (Title V) tracks the performance, compliance, operational status and major source status of all permitted sources, incl uding wool fiberglass facilities currently in operation in the U.S. In finalizing this rule, we have not included sources that have been identified by the Title V program as area sources in the floor calculations. Therefore, true area sources (i.e., source s that do not have the potential to emit at least 10 tons per year of a single pollutant or at least 25 tons per year of any combination of HAP) were not

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part of the MACT floor calculation for phenol, formaldehyde, or methanol. We note that most of the sou rces identified by the commenter as area sources were not described as area sources in the May 5, 2010 letter that was submitted in response to the voluntary survey conducted by the commenter. The letter states in pertinent part “[n]ew PM2.5 [and] total PM will be collected from Knauf’s Lannett, Alabama facility (621 Furnace)”(p.5);” [n]ew PM2.5 [and] total PM data will be collected from Johns Manville’s Richmond, Indiana facility (Melter)”(p.7);[e]xisting PM2.5 [data] will be provided from Knauf’s Shasta L ake, California facility” (p.7); and [e]xisting PM 2.5, and total PM data from Johns Manville’s Willows California facility will be provided.” (p. 9).”

As explained in the 2011 proposal, industry conducted a voluntary survey among all owners and operator s of mineral wool and wool fiberglass manufacturing facilities that were major sources. The survey sought test data for PM, CO and HAP emissions and information on process equipment, control devices, point and fugitive emissions, practices used to control point and fugitive emissions. Further, the EPA requested and industry agreed in a May 5, 2010 letter (see Appendix A of docket item number EPA

- HQ

- OAR

- 2010

- 1041

- 0080), that a subset of facilities that were representative of emission sources from both the mi neral wool and wool fiberglass industries would conduct emissions testing. The May 5, 2010 letter indicated that the bases for representativeness included design type and size of process units or equipment, fuel type, operating temperatures, control device s and raw material content. The commenter did not identify in its May 5, 2010 letter these two synthetic area sources as synthetic area sources or as not representative of major sources. Rather, the letter states in pertinent part that “[n]ew hydrogen fluo ride and hydrochloric acid data will be collected from USG Interiors’ Walworth, Wisconsin facility (1 Cupola) [and] [n]ew HF and HCl will be collected at USG Interiors’ Red Wing, MN facility.” (May 5, 2010 letter, p. 14). (“ EPA typically has wide latitude in determining the extent of data

- gathering necessary to solve a problem. We generally defer to an agency's decision to proceed on the basis of imperfect scientific information, rather than to invest the resources to conduct the perfect study. ” Sierra Club v. EPA , 334 U.S. App. D.C. 421, 167 F.3d 658, 662 (D.C. Cir. 1999) (citation omitted) ).

Synthetic area sources are essentially major sources by design that agree to operate at a level that is synonymous with area sources. Due to their design, emissions fr om a synthetic area source are reflective of emissions from a major source. Their reduced level of operation to qualify to be a synthetic area source has no impact on the representativeness of their emission data as a major source. The commenter has argued elsewhere (see comment number 6 7 ) that the proposed HF and HCl emission limits are flawed due to limited data availability. Use of these data for the two synthetic area sources provides more data availability. For these reasons and the reasons stated abov e, the EPA has established no justification for removing the emission data for these two synthetic area sources from its emission dataset.

69. Comment: One commenter (1041

- 0080/1041

- 1026) argued that the EPA should have counted the data from two sources that s hare a common exhaust stack as only a single

source , and should not have counted them twice when doing the MACT floor calculation s. According to the commenter, the EPA should not have counted the two cupolas that share one exhaust stack at two of the facil ities (Isolatek and USG’s Red Wing, MN) because in each case the single stack should count as one point source. The commenter argued that counting one point source as two was inaccurate, particularly when the emissions from each cupola cannot be

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accurately ascertained. The commenter urged the EPA to count each of these facilities as one source, not two. As an alternative, the commenter suggested that because the EPA cannot distinguish the specific data for each cupola, the EPA should not include any of thes e data to set the MACT floor. The commenter stated that this approach would enable the EPA to establish a limit that is more representative of the actual performance of the industry.

Response: The EPA disagrees with commenter. As explained in the Industria l Boiler NESHAP, the EPA continues to believe that emissions from a common stack should be considered as representing the average emissions of process units, in this instance a cupola or furnace, exhausting to the common stack and thus, should be considere d representative of emissions from both process units or cupolas or furnaces. The commenters have provided no data to support the contention that this assumption is false. The EPA used data from combined stacks where multiple cupolas or furnaces were route d to a common stack and control device. Emissions were allocated to each cupola or furnace based on production capacities. Similar to testing conducted for the voluntary survey, the EPA expects that companies will comply with the final rule by conducting t esting at the common stack as that is usually where the sampling locations are (rather than in the intermediate ductwork) and will report the results as being for each cupola or furnace.

Further, the commenter’s May 5, 2010 letter (see Appendix A of docket item number EPA

- HQ

- OAR

- 2010

- 1041

- 0080) indicated that mineral wool production facilities would be conducting and submitting test results for the two cupolas that are the subject of this comment

Isolatek and Red Wing. At the time, the commenter only ident ified two cupolas at the Isolatek facility as having “combined baghouse/combined point source." No mention was made of USG's Red Wing cupola as sharing common control equipment. (May 5, 2010 letter, pp. 13

- 14). Second, the EPA requested testing of all emis sions points and the submission of test results as part of the voluntary survey. Specifically, Enclosure 2 of the survey requested testing at both the inlet and outlet of each cupola. "Testing should be conducted on 1) both the inlet and outlet for CO and COS testing on the cupola and organic HAP testing on the curing oven and 2) the outlet from at least one of the controls systems used to control emissions from the [each fiber collection operation, each curing oven and each cooling operation]. . . If the p rocess unit you are testing does not have a control system, test the outlet from your process unit." Section 1.2, Enclosure 2. Third, as earlier explained, the EPA and industry agreed that a subset of facilities that were representative of emission sources from both the mineral wool and wool fiberglass industries would conduct emissions testing. The May 5, 2010 letter indicated that the bases for representativeness included design type and size of process units or equipment, fuel type, operating temperature s, control devices and raw material content. The EPA and industry agreed to submission of data that would be considered representative of other process units. The commenter's response in relevant part was that "“[n]ew hydrogen fluoride and hydrochloric aci d data will be collected from USG Interiors’ Walworth, Wisconsin facility (1 Cupola) [and] [n]ew hydrogen fluoride and hydrochloric acid will be collected at USG Interiors’ Red Wing, MN facility.” (May 5, 2010 letter, p. 14). Moreover, owners or operators of these facilities certified the results submitted to the agency as being true, accurate, and complete.

The EPA has reviewed the data based on comments received and does not believe that there are any inconsistencies in the data set used for the final ru le. In the MACT floor analysis, the EPA used data only from stacks that were tested or for which test data were provided.

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(“ EPA typically has wide latitude in determining the extent of data

- gathering necessary to solve a problem. We generally defer to an agency's decision to proceed on the basis of imperfect scientific information, rather than to invest the resources to conduct the perfect study. ” Sierra Club v. EPA , 334 U.S. App. D.C. 421, 167 F.3d 658, 662 (D.C. Cir. 1999) (citation omitted) )

.

70. Comment: One commenter (1041

- 0080/1041

- 0126) recommended that data characterized as below

- the

- minimum

- detection

- limit (below

- MDL) should not be used to set the MACT floor because such data are unquantifiable. The commenter (1041

- 0080) requested that the EPA remove the Industrial Insulation Group (IIG) data from the calculation for the MACT floor because below

- MDL data are unquantifiable. The commenter expressed concern that using below

- MDL data is likely to set limits so stringent that even the best performing sourc es cannot meet those limits. The commenter cited a memorandum from RMB Consulting and Research about relying on below

- MDL data. 25

According to the commenter, the EPA should use only values that are above the MDL (i.e., actual values) in calculating the MAC T floor. The commenter stated that the emissions floor must be determined by quantifiable data, and thus, the EPA should not use the IIG data to set the MACT floor.

The commenter (1041

- 0126) said that the EPA should allow those sources whose tests showed r esults below the detection limits of the method to use work practices rather than testing to show compliance with the emission limits of the rule.

Response: The EPA disagrees with the commenter’s assertion that data returned from an ICR with a value report ed as below the detection limit should be excluded from the MACT floor data set simply because a specific value for this data is not reported. Where no detection of an analyte is found across an industry sector, we find no need to regulate such pollutants as they are not present in measureable quantities; however, in an industry sector where the pool of best performing units are represented, in part, by measured and in part by values at or below the method detection limit, we have no discretion available w ith which to exclude data at or below the method detection limit from the pool of best performing units and, as a matter of practice, assign a value at the method detection limit to those data for the purposes of conducting the MACT floor analysis. We also disagree that use of such data would result in limits so stringent that they cannot be met by the best performing sources.

A small percentage of the tests at cupolas returned values for HF and HCL that were BDL of the method. With such data, that often represent best performing units in a data set, we use a procedure for identifying a representative method detection level (RDL). The procedure for determining an RDL starts with identifying all of the available reported pollutant specific method detection levels for tests of the best performing units regardless of any subcategory (e.g., existing or new, fuel type). By limiting the data set to those tests used to establish the floor or emissions limit (i.e., best performers), we believe that the result is r epresentative also of the better performing testing companies and laboratories. From that combined pool of data, we calculate an arithmetic mean value. The averaging step would minimize the effect of a test(s) with an

25 RMB Consulting & Research, Inc. Memorandum, Comments on Proposed EGU MACT Rule, July 19, 2011,
p. 18.

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inordinately high method detection lev el (e.g., the sample volume was too small, the laboratory technique was insufficiently sensitive, or the procedure for determining the detection level was other than that specified). We then call the resulting mean of the method detection levels as the RDL as characteristic of accepted source emissions measurement performance.

The second step in the process is to calculate three times the RDL to compare with the calculated floor or emissions limit. Using a multiplication factor of three is comparable to
pr actice common among testing and analytical laboratories for defining a measurement reporting limit. This step is also similar to what we have used in other rulemakings, including for the Portland cement MACT determination. The multiplication factor of thre e approximates a 99

- percent upper confidence interval for a data set of 7 or more values. We then compared this value to the calculated floor and if three times the RDL were less than the calculated floor or emissions limit (e.g., calculated from the UPL), we would conclude that measurement variability was adequately addressed. The calculated floor or emissions limit would need no adjustment. If, on the other hand, the value equal to three times the RDL were greater than the UPL, we would conclude that the calculated floor or emissions limit does not account entirely for measurement variability. If indicated, we substituted the value equal to three times the RDL for the calculated floor or emissions limit.

We determined the RDL for each pollutant using data from tests of all the best performers for all of the final regulatory subcategories (i.e., pooled test data). We applied the same pollutant

- specific RDL and emissions limit adjustment procedure to all subcategories for which we established emissions limits . We believe that emissions limits adjusted in this manner better ensure measurement variability is adequately addressed relative to compliance determinations than did the procedure applied for the proposal that may have been based on data sets smaller tha n seven tests and as few as one test. We also believe that the emissions testing procedures and technologies available now and in the future will be adequate to provide the measurement certainty sufficient for sources to demonstrate compliance at the level s of the adjusted emissions limits.

We note that the use of the RDL in establishing the emission limits for HF and HCl is consistent with the approach approved by the court in NACWA v. EPA , 734 F.3d 1115, 1154

– 55:

“We agree with EPA that its method of incorporating nondetect data is reasonable, and not arbitrary or capricious. We do not expect EPA to perform the impossible, s ee Cement Kiln , 255 F.3d at 871, and that includes recording emission levels that are not accurately detectable with its current e missions testing technology. As EPA explains the issue, emission levels from zero up to some value above the method detection level cannot be stated with accuracy. Because any emission level EPA selects at that point will necessarily be an estimate, EPA ad opted a method to account for measurement imprecision that has a rational basis in the correlation between increased emission values and increased testing precision.”

71. Comment : One commenter (1041

- 0080/1041

- 0126) recalculated the MACT floor for HCl and HF after eliminating the three following categories of mineral wool production facilities, and recommended that the EPA adopt these revised limits: (1) synthetic area sources,

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(2) sources that share common stacks/controls that were represented by one data poi nt (Isolatek and USG

– Red Wing), and (3) sources with data that were below

- MDL (IIG). The commenter’s rationale for eliminating each of these three categories of sources is summarized in comment numbers 68
, 69 , and 70 . The commenter’s MACT floor calculati ons for HCl and HF are shown in the two following tables:

Facilities HCl Emission Limit (lb/ton of melt)

Average of Cupolas 99% UPL Existing Sources Multiplied Average by 2 Multiplied Average by 2.5 Multiplied Average by 3

Rock Wool & Thermafiber 0.098 0.249 0.196 0.245 0.294

Facilities HF Emission Limit (lb/ton of melt)

Average of

Cupolas 99% UPL Existing Sources Multiplied Average by 2 Multiplied Average by 2.5 Multiplied Average by 3

Rock Wool, Thermafiber, & Amerrock 0.0844 0.190 0.169 0.211 0.2532

Response : As explained in section VI.D of the preamble to this final rule and also in this response to comment document, w e are not adopting the numerical limits proposed on November 25, 2011 for HCl and HF emissions from cupolas. As explained in our proposal on April 15, 2013, we are subcategorizing cupolas according to whether they use slag in the raw material introduced to the cupola, and are finalizing the 2014 proposed HF and HCl limits specific to these two different subcategories. We also note that the commenter subsequently expressed support for the finalized HCl and HF limits for existing sources, as summarized in comment number 6 2

. We disagree with the commenter’s recommended alternative calc ulations because they are not permissible under the CAA, as discussed in the EPA’s responses to comment numbers 70
, 71 , and 72 . As discussed earlier in response to comment numbers 68
, 69 , and 70
, respectively, the EPA cannot exclude synthetic area sources from the MACT analysis, the EPA must consider sources with shared stacks and can treat them as two distinct sources, and the EPA must account for measures of emitted HAP that are at or below the MDL.

72. Comment: One commenter (1042

- 0080) urged the EPA to esta blish risk

- based standards for HCl and HF emissions from the mineral wool industry. The commenter noted that CAA section 112(d)(4) expressly authorizes the EPA to establish risk

- based standards for threshold pollutants for which a health threshold has been established. 42 U.S.C. § 7412(d)(4). The commenter asserted that this provision was established by Congress because "[f]or some pollutants a MACT emissions limitation may be far more stringent than is necessary to protect

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public health and the environment " and quotes from the legislative history for the 1990 CAA amendments. The commenter also asserted that EPA has previously determined that HCl is a threshold pollutant. It also asserts that the EPA has established what the commenter characterized as a lack of risk. The commenter further assert ed that health

- based limits would be more reasonable and achievable and would enable the EPA to achieve the ample margin of safety to health and the environment.

Response: Section 112(d)(4) of the CAA provides that: "[ w]ith respect to pollutants for which a health threshold has been established, the Administrator may consider such threshold level, with an ample margin of safety, when establishing emissions standards under this subsection." Notably, the statute confers l imited discretionary authority on the EPA and does not mandate the use of health

- based standards. The legislative history cited by the commenters contains similarly permissive language and does not suggest that health

- based standards would be required in a ny circumstances. Specifically, the legislative history quoted by the commenter provides that "where health thresholds are well

- established . . . and the pollutant presents no risk of other adverse health effects, including cancer, for which no threshold c an be established, the administrator may use the threshold with an ample margin of safety (and not considering cost) to set emissions limitations for sources in the category or subcategory." S. Rep. No. 101

- 228, at 144 (1989). In other words, where certai n preconditions are met (i.e. health thresholds are well

established and the pollutant presents no other risks), the EPA has discretionary authority to set health

- based standards. Here, the commenter urges the EPA to create risk

- based limits based largely on their assertion that EPA has authority to do so because the pre

- conditions are met. The commenter does not, however, offer a rationale to support their assertion that the EPA should exercise this discretionary authority in this rulemaking. In fact, the only rationale offered is a bald assertion that such limits would be more reasonable and achievable and would enable the EPA to achieve the ample margin of safety to health and the environment. This comment was offered in response to the 2011 proposal, as pects of which were modified in the 2013 proposal. As explained in the 2013 proposal (78 FR 22370 at 22389), the HF and HCl standards are not only reasonable and achievable, but will in fact have minimal impact on the mineral wool industry.

73. Comment: One c ommenter (1041

- 0126/1041

- 0164) supported the subcategories in the proposed rules published on April 15, 2013 and November 13, 2014, that proposed separate limits with respect to HF and HCl emissions for cupolas processing slag and cupolas not processing sl ag. Previously, in response to the 2011 proposal, the commenter (1041

- 0080) had recommended that the EPA subcategorize cupolas and provided a rationale for each of their recommended subcategory options based on six criteria: ( 1) permitted capacity (permitt ed maximum melt rate); ( 2) manufactured product (residential loose fill insulation, ceiling tiles, fireproofing materials, and commercial and industrial insulation); ( 3) raw material (i.e., recycled slag vs. mineral rock (non

- recycled material)); ( 4) bonde d vs. unbonded products; ( 5) unique fuels and raw materials that would put each facility in its own separate subcategory; and ( 6) air pollution control differences (i.e., cupolas with an incinerator vs. those without). The commenter also said that the EPA was assuming that raw material substitution could reduce the HCl, HF, and COS emissions to the proposed limits. According to the commenter, there are no supporting data, analyses, or feasibility determinations in the docket to support the EPA’s assumption, and therefore, the proposed standards are unsupported on the record and patently arbitrary.

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Response: The a gency acknowledges the commenter’s support for HCl and HF limits proposed in 2013 and 2014 for two different subcategories of cupolas according to w hether slag is among the raw materials melted in the cupola. As the EPA specified in the 2013 proposal (78 FR 22385), the EPA considered the information provided by the commenter in response to the 2011 proposal, and the EPA obtained and reviewed additiona l information from industry regarding which companies use slag in the cupola and which do not as well as the emissions characteristics of the different raw material mixtures. These data indicate that there are differences in the emissions of the acid gases HF and HCl depending on whether slag is used in the cupola to produce mineral wool. Of the 7 facilities, three reported using slag and four reported only using minerals (rock) and coke (e.g., no slag). Slag is a waste by

- product from the iron and steel in dustry and is location

- specific depending on the type of facility/process generating the slag. Some types of slag have residual fluorides or chlorides which vary from location to location and from process to process. The EPA determined that cupolas that di d not process slag had lower emissions of acid gases than those that did not. We agreed with the commenter that cupolas could be subcategorized according to these raw material differences, and in April 2013 we proposed to subcategorize the mineral wool cup olas into two categories (those that process slag materials and those that do not), and we proposed revised standards for HCl and HF based on the cupola subcategories. Subsequently, the EPA applied its updated approach for evaluating limited datasets to th e HF and HCl emission limits and proposed revised limits in November 2014 (79 FR 68017) for the same two subcategories of cupolas: those that process slag and those that do not. The finalized emission limits for HF and HCl reflect the same subcategories as proposed in 2014.

74. Comment: One commenter (1041

- 0080) recommended that the EPA use the following alternative emission limits for HCl and HF because the majority of the commenter’s members cannot meet the EPA’s proposed limits for HCl and HF, and none of the commenter’s members were confident that the proposed HCl and HF limits proposed on November 25, 2011, could be met on a consistent basis. The commenter also argued that raw material substitution was not a feasible alternative to me et the proposed limits. These alternative limits were formulated by the commenter as follows:

Formula for calculating X at a known cumulative probability (99.0 percent):


### X = x + Z(.99)* s

Pollutant Emission Limit (lb/ton of melt)
Existing Cupol as New and Reconstructed Cupolas

HCl 0.258 0.258

HF 0.172 0.172

COS 8.4 8.4

With a 99 percent calculated probability, the commenter recommended that these limits could be generally met by all mineral wool companies.

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Based on the commenter’s statistical/probability calculations using existing mineral wool HCl and HF data, the commenter estimated the following probabilities of failing to meet the EPA’s proposed limits and the commenter’s recommended limits:

• HCl

– with t he EPA’s proposed limit, there is a 77.1 percent chance of failure to meet the proposed limit.

• HCl

– with the commenter’s recommended limit, there is 1.0 percent chance of failure to meet the limit.

• HF

– with the EPA’s proposed limit, there is a 78.8 perce nt chance of failure to meet the proposed limit.

• HF

– with the commenter’s recommended limit, there is 1.0 percent chance of failure to meet the limit.

According to the commenter, adoption of these recommended limits would: ( 1) eliminate the need to instal l costly wet scrubber/dry scrubber; ( 2) avoid costs of control equipment too burdensome for small businesses; ( 3) establish measurable/quantifiable emission limits; ( 4) avoid environmental waste caused by installation of wet scrubbers; ( 5) preserve the EPA’s objective of avoiding installation of new control equipment as stated in the Proposed Rule; and ( 6) establish limits commensurate with the low level of risk posed by HCl and HF from the mineral wool industry.

Response: We note that th e commenter subsequently expressed support for the HCl and HF limits being finalized for existing sources (1041

- 0164), as summarized in comment number 6 2 . As explained in section VI.D of the preamble to th e final rule and in the November 13, 2014 supplemen tal proposal, we are not finalizing the numerical limits for HCl and HF emissions from cupolas presented in the November 25, 2011 notice, but are setting emission limits for two subcategories of cupolas: cupolas that process slag and those that do not proc ess slag. Further, as explained in the 2014 proposal, the finalized HCl and HF limits for new and existing sources in each subcategory were calculated using the UPL approach to account for uncertainty and variability in the measured emission levels. For mo re information on the EPA’s approach to calculating the finalized limits for HCl and HF, refer to the memoranda “Revised Technical Approach for Mineral Wool MACT Floor Calculations” (docket item number EPA

- HQ

- OAR

2010

- 1041

- 0156) and “ Approach for Applying the Upper Prediction Limit to Limited Datasets

– Ferroalloys ” (docket item number EPA

- HQ

- OAR

- 2010

- 1041

- 0129).

The limits suggested by the commenter for existing sources, in response to the 2011 and 2013 proposals, were not supported by the test data submi tted by industry for this source category, and as such are not permissible under CAA section 112. To set the level of the MACT floor at the level suggested by the commenter would be to set the floor on the highest emitting source; that is, a level that cou ld be achieved by all existing sources in the industry. As earlier explained, however, the D.C. Circuit has consistently rejected a reading of “achieved by the best performers,” in section 112(d)(3), as meaning achievable by all sources within a source cat egory. “EPA’s rationales . . . amount to nothing more than concern about ensuring that its floor is achievable by all kilns in the subcategory

-- precisely the position we rejected in Cement Kiln.” Sierra Club v. EPA

, 479 F.3d at 881. See also, Cement Kiln R ecycling Coalition v. EPA , 255 F.3d at 861 “EPA may not deviate from section 7413(d)(3)’s requirement that floors reflect what

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the best performers actually achieve by claiming that floors must be achievable by all sources using MACT technology.” (“EPA cann ot circumvent Cement Kiln ’s holding that section 7412(d)(3) requires floors based on the emission level actually achieved by the best performers (those with the lowest emission levels), not the emission level achievable by all sources, simply by redefining “best performing” to mean those sources with emission levels achievable by all sources.”). Sierra Club v. EPA , 479 F.3d at 881. ( E mphasis in original).

Also, regarding the comment on the 2011 proposed rule’s potential impact to small businesses, while the EPA may use regulatory flexibility to ease section 112 impacts on small businesses such as those in the mineral wool industry, the EPA may not dismiss the requirements of CAA section 112 due to small business impacts.

C. Cupola COS Limit

75. Comment: One comment er (1041

- 0126/1041

- 0164) supported the subcategories in the proposed rules published on April 15, 2013 and November 13, 2014, that established separate limits with respect to COS emissions for closed top and open top cupolas.

Response: The a gency acknowledges the commenter’s support.

76. Comment: One commenter (1041

- 0164) supported the proposed COS emission limits published on November 13, 2014 for existi ng sources within both the open

- top and closed

top subcategories for cupolas.

Response: The a gency acknowledges the commenter’s support.

77. Comment: One commenter (1041

- 0164) opposed the COS emission limits proposed on November 13, 2014 and being finalized in this action for new sources within both the open top and closed top subcategories for cupolas. The commenter argued that t he proposed emission limits are too stringent and technology is not available to achieve compliance with those proposed limits.

Response: In the 2011 proposed rule, limits were proposed for COS to replace the use of CO as a surrogat e for COS. In the 2013 and 2014 proposed rules, the proposed limits were revised to reflect the addition of subcategories for cupolas that are open topped and those that are closed topped, and to reflect the performance of the best controlled similar sourc e as the limit for

new sources. Congress specified in CAA section 112(d)(3) the minimum level of emission reduction that could satisfy the requirement to adopt MACT. For new sources, this floor level is “the emission control that is achieved in practice by the best controlled similar source.” The EPA’s analysis of the available data indicate that the proposed limits for new sources are achievable using the controls identified as MACT, as discussed in the preamble to the 2014 proposed rule (79 FR 68020) and in the supporting memo in the docket for this rulemaking (EPA docket item EPA

- HQ

- OAR

- 2010

- 1041

- 0156).

Further, section 112(d) requires the EPA to promulgate standards for major sources of HAP that are based on MACT performance. For existing sources, MACT s tandards must be at least as stringent as the average emissions limitation achieved by the best performing 12 percent of existing sources (for which the Administrator has emissions information) or the best

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performing 5 sources for source categories with le ss than 30 sources. The worst performing sources would have to take action to reduce their air toxic emissions. As a general matter, emissions standards under section 112(d) include measures that “reduce the volume of, or eliminate emissions of pollutants through process changes, substitution of materials or other modifications.”

78. Comment: One commenter (1041

- 0080) stated that the proposed limits for COS published on November 25, 2011, are not achievable for the entire industry without additional control equ ipment. Specifically, based on new and existing data, the commenter expressed concern that the following two existing facilities would have problems meeting the EPA’s 2011 proposed limit for COS:

• Rockwool

– New and existing data shows that the limit cannot be met.

• Amerrock

– Data show that meeting the proposed limit consistently may be problematic.

According to the commenter, data show that the four remaining companies can meet the EPA’s 2011 proposed limit range. However, the commenter stated that many of these companies expressed concern about meeting the limits consistently, and therefore, all companies supported a revised limit.

The commenter asserted that COS should not be regulated as a HAP. The commenter argued that the majority of COS emissions origi nate from nature, the scientific record does not support COS as a significant risk, and because COS emissions do not present any threat to public health or the environment, imposing stringent COS emissions limitations would simply be regulation for regulat ion’s sake. The commenter stated that such an approach is not necessary under the law and not justifiable in light of the significant costs that would be incurred by affected sources. The commenter recommended alternatives to the proposed rule.

Response: W e note that this commenter subsequently expressed support for the finalized COS limits for existing sources (for both open

- top and closed

- top subcategories of cupolas), as summarized in comment number 7 6

. In 2011, we proposed COS emissions limit that would apply to all cupolas in the industry without regard to design. In response to our 2011 proposal, we received additional information from industry indicating that two types of cupolas are used in the production of mineral wool: cupolas with closed tops and those with open tops. Based on this additional information, we identified that there are two operating open

- top cupolas and 9 closed

- top cupolas. As explained in the preamble to the April 15, 2013 supplemental proposal, we proposed separate subcategories for open

- top and closed

- top cupolas.

In 2014, we proposed a limit of 3.4 lb COS/ton melt for closed

- top cupolas at existing sources. We also proposed a limit of 6.8 lb COS/ton melt for open

- top cupolas at existing sources. We based the COS emission limits for these two cupola subcategories on the MACT floor calculation as required under CAA section 112. A more detailed explanation of how we calculated the MACT floors can be found in the memo randum , " Revised Technical Approach for

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Mineral Wool Production MA CT Floor Calculations ," which is in the docket for this rulemaking (see docket item number EPA

- HQ

- OAR

- 2010

- 1041

- 0156).

While the commenter contends that COS emissions also originate from non

anthropogenic sources, this does not affect that COS is a listed HAP for regulation under section 112 of the CAA, and that the EPA must regulate such HAP under section 112 provisions. We also note that any individual or group may petition to add or delete a chemical from the list of HAP under CAA section 112(b)(3)(A).

The EPA recognizes that the final limits would not necessarily be met by all mineral wool producers without the addition of either control equipment or selection of raw materials with lower sulfides content. As explained in detail in the EPA’s response to comment number 5 7 , the D.C. Circuit has consistently rejected a reading of “achieved by the best performers,” in CAA section 112(d)(3), as meaning achievable by all sour ces within a source category.

79. Comment : One commenter (1042

- 0080) urged the EPA to estab lish risk

- based standards for COS emissions from the mineral wool industry. The commenter noted that CAA section 112(d)(4) expressly authorizes the EPA to establish risk

- based standards for threshold pollutants for which a health threshold has been establi shed. 42 U.S.C. § 7412(d)(4). The commenter asserted that this provision was established by Congress because "[f]or some pollutants a MACT emissions limitation may be far more stringent than is necessary to protect public health and the environment" and qu otes from the legislative history for the 1990 CAA amendments. The commenter also asserted that the EPA has previously determined that COS is a threshold pollutant. It also asserts that the EPA has established what the commenter characterized as a lack of risk. The commenter further asserted that health

- based limits would be more reasonable and achievable and would enable the EPA to achieve the ample margin of safety to health and the environment.

Response: Section 112(d)(4) of the CAA provides that: "[w]it h respect to pollutants for which a health threshold has been established, the Administrator may consider such threshold level, with an ample margin of safety, when establishing emissions standards under this subsection." Notably, the statute confers limit ed discretionary authority on the EPA and does not mandate the use of health

- based standards. The legislative history cited by the commenters contains similarly permissive language and does not suggest that health

- based standards would be required in any circumstances. Specifically, the le gislative history quoted by the commenter provides that "where health thresholds are well

- established . . . and the pollutant presents no risk of other adverse health effects, including cancer, for which no threshold can be established, the administrator m ay use the threshold with an ample margin of safety (and not considering cost) to set emissions limitations for sources in the category or subcategory." S. Rep. No. 101

- 228, at 144 (1989). In other words, where certain preconditions are met (i.e. health t hresholds are well

established and the pollutant presents no other risks), the EPA has discretionary authority to set health

- based standards. Here, the commenter urges the EPA to create risk

- based limits based largely on their assertion that EPA has author ity to do so because the pre

- conditions are met. The commenter does not, however, offer a rationale to support their assertion that the EPA should exercise this discretionary authority in this rulemaking. In fact, the only rationale offered is a bald asse rtion that such limits would be more reasonable and achievable and would enable the EPA to achieve the ample margin of safety to health and the environment. This comment was

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offered in response to the 2011 proposal, aspects of which were modified in the 20 13 proposal. As explained in the 2013 proposal (78 FR 22370 at 22389), the final COS standard is not only reasonable and achievable, but will in fact have minimal impact on the mineral wool industry.

80. Comment : The commenter (1041

- 0080) argued that the EPA i s not required to set standards for COS emissions from the mineral wool industry, and urged the EPA to forego setting any COS emission limits from cupola furnaces. The commenter also stated that the EPA is not required to “correct” existing MACT standards when it conducts a review under CAA section 112(d)(6). According to the commenter, even if the EPA decides to set a standard for COS, it is not required under CAA section 112(d)(6) to set a “floor” when doing so.

Response : As explained in earlier response s , the D.C. Circuit has held that the EPA may permissibly amend improper MACT determinations, including amendments to improperly promulgated floor determinations, using its authority under sections 112(d)(2) and (3). Refer to the EPA’s response to comment number 6 6 for a detailed discussion of these rulings. We also note that, i n National Lime Association v. EPA , 233 F.3d 625 (D.C. Cir. 2000), the D.C. Circuit remanded the Portland Cement MACT to the EPA to establish MACT floors for HCl holding that we had a clear “statutory obligation to set emission standards for each listed HAP.” A detailed discussion of this court case and the EPA’s authority to address potential revisions to a promulgated standard (e.g., the fact that we used improper surrogates (such a s CO) in the 1999 NESHAP for the mineral wool production source category ) is provided in the EPA’s response to comment number 6 6

. The EPA further discusses its assessment of the use of surrogates in the 1999 NESAHP in section IV.C.4 of the preamble to the final rule.

Further, in several recent rulemakings, we have chosen to fix underlying defects in existing MACT standards under CAA sections 112(d)(2) and (3), as discussed in the EPA’s response to comment number 5 6

. As also explained in various responses in cluding comment number 66 , we disagree with the comment that CAA section 112(d)(6) is the EPA’s sole authority for revising existing MACT standards. We believe that CAA section 112 does not expressly address this issue, and that the EPA has discretion in d etermining how to address potential revisions to a promulgated standard. CAA section 112(d)(6) provides that the agency must review and revise “as necessary.” The “as necessary” language must be read in the context of the provision, which focuses on the re view of developments that have occurred since the time of the original promulgation of the MACT standard and thus, should not be read as a mandate to correct flaws that existed at the time of the original promulgation.

81. Comment : One commenter (1041

- 0080) ur ged the EPA to apply a more liberal variability factor in calculating the 2011 proposed COS limit to avoid a scenario of frequent non

compliance. According to the commenter, all mineral wool companies expressed concern about meeting the limit for new and r econstructed sources. At a minimum, the commenter requested that the EPA set the COS limits for new sources that are equal to the limits for existing sources identical limits, as the EPA did for HF and HCl in the November 25, 2011 proposed rule.

Further, the commenter stated that the mineral wool industry provides environmental benefits by creating a product that increases energy efficiency and by re

- using blast furnace slag

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as an input material. The commenter argued that the EPA should avoid directly impo sing overly stringent or unnecessary emission limits or indirectly imposing technological requirements that will threaten the viability of mineral wool companies that provide such significant environmental benefits. Therefore, the commenter strongly urged the EPA to consider alternatives to imposing a COS MACT limit.

Response : Congress specified in CAA section 112(d)(3) the minimum level of emission reduction that could satisfy the requirement to adopt MACT. For new sources, this floor level is “the emissio n control that is achieved in practice by the best controlled similar source.”

For existing sources, MACT standards must be at least as stringent as the average emissions limitation achieved by the best performing 12 percent of existing sources (for which the Administrator has emissions information) or the best performing 5 sources for source categories with less than 30 sources. The worst performing sources would have to take action to reduce their air toxic emissions. Thus, CAA section 112(d) requires the EPA to establish the MACT floor for new sources differently for new sources and existing sources and the EPA is prohibited from adopting the same standard for new sources as for existing sources, as recommended by the commenter, where the available dat a indicate that new sources can achieve a more stringent level of control, which is the case here. As such, the EPA may not set the COS limits for new sources equal to the limits for existing sources because the available data indicates that new sources ca n achieve “the emission control that is achieved in practice by the best controlled similar source.”

Regarding the comment that the EPA proposed in 2011 equivalent new and existing source limits for HCl and HF, we acknowledge that the emission limits for n ew and existing sources were the same in the 2011 proposal. However, we revised the emission limits in the 2013 supplemental proposal based on subcategories develop for slag and non

- slag using cupolas (78 FR 22385

- 22386). In the 2014 supplemental proposal (79 FR 68019), we further revised the HF and HCl emissions for new sources using our updated approach for evaluating limited datasets. This is to be consistent with CAA section 112(d)(3).

Further, regarding the comment that EPA should apply a more liberal variability factor, we do not believe that such a factor would be consistent with our authority to set MACT standards under CAA section 112(d). We note that the EPA’s more recent approach in the 2014 proposal for setting MACT standards employs a formula th at accounts for variability, which was described in the preambles to the proposed rules published on April 15, 2013 and November 13, 2014. See the memoranda “Approach for Applying the Upper Prediction Limit to Limited Datasets” (docket ID EPA

- HQ

- OAR

- 2010

- 1 042

- 0331) and “Use of the Upper Prediction Limit for Calculating MACT Floors” (docket ID EPA

- HQ

- OAR

- 2010

- 1042

- 0333) prepared for the 2014 supplemental proposal. As explained in the preamble to the final rule, we are promulgating a limit of 3.4 lb COS/ton m elt for closed

- top cupolas at existing sources. We are also promulgating a limit of 6.8 lb COS/ton melt for open

- top cupolas at existing sources. These limits were calculated using the 99

- percent UPL for existing sources.

Regarding the comment that the EPA should avoid imposing overly stringent or unnecessary emission limits or indirectly imposing technological requirements that will threaten the viability of mineral wool companies, the EPA is precluded from considering costs in

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calculating MACT floors. Nat ional Lime Ass’n v. EPA , 233 F.3d at 640. Section 112(d) of the CAA requires the EPA to promulgate standards for major sources of HAP, and COS is on the list of HAP that can be found in CAA section 112(b). Additionally, as noted in the EPA’s response
to co mment number 7 8 , petitions to add or delete chemicals from the list of HAP are allowed under CAA section 112(b)(3)(A).

In response to the commenter’s statement that incineration of COS would create SO 2 and NO X emissions, we note that, while several source s already incinerate COS and other sources could also install controls on added incinerators that would reduce SO 2 and NO x , this would be done at great expense and for little environmental benefit. We have instead exercised our discretion under CAA section 112(d) to subcategorized cupolas according to whether they are
open

- or closed

- top, as this design feature factors prominently into the COS emission potential of cupolas.

We note that the commenter subsequently expressed support (1041

- 0164) for the COS l imits for existing sources in the 2014 proposal and being finalized, as summarized in comment number 76

.

82. Comment: One commenter (1041

- 0080) described the EPA’s MACT floor calculation methods in the November 25, 2011 proposed rule as improper. According to the commenter, a thorough and complete analysis of the EPA’s calculation method was not possible because the preamble to the proposed rule and the MACT floor memorandum lacked details of the data the EPA relied on in its analysis and calculations. As a res ult, the commenter challenged the record as inadequate. According to the commenter, the EPA has improperly exercised its discretion and failed to provide an assessment of how many actual mineral wool cupolas would be able to meet the standards without inst alling further controls. The commenter highlighted the need for a full explanation of how the UPL was determined for the mineral wool industry, including the statistical analysis related to the normality of the test data and transformation of the data to p roduce a suitable distribution. The commenter argued that the absence of the identified data was a significant lapse, given that the CAA requires the EPA to include in the record a “statement of basis and purpose” that should include such information. The commenter stated that its absence violated CAA section 307, and, if not corrected prior to promulgation, would render the final rule arbitrary.

Response: We note that the commenter subsequently expressed support (1041

- 0164) for the COS limits for existing sources in the 2014 proposal and being finalized, as summarized in comment number 7 6 . We disagree with this comment on the 2011 proposal that the EPA did not provide complete disclosure, and we believe we clearly presented the data source and our approach used to calculate the MACT floors. Please refer to the EPA’s response to comment

num ber 7 8 for a detailed discussion of how the EPA provided the data sources, our approach to calculating all MACT floors (including a list of documents that the EPA provided in the docket), a description of the test data collected by the EPA, and the comment er’s indication back in 2010 that these data were representative of industry emissions.

In the April 15, 2013 proposal (78 FR 22385) and in the memorandum “ Technical Approach for Mineral Wool MACT Floor Calculations ” (docket item number EPA

- HQ

- OAR

2010

- 10 41

- 0109), we presented our rationale for developing subcategories for different types of

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cupolas and for revising the COS emission limits using the UPL approach. Additionally, more recently in the November 13, 2014 proposal (79 FR 68019) and in the memoran dum “ Revised Technical Approach for Mineral Wool MACT Floor Calculations” (docket item number EPA

HQ

- OAR

- 2010

- 1041

- 0156), we subsequently proposed and discussed our decision to revise the COS emissions limits for cupolas based on our updated approach for e valuating limited data sets (also see the memorandum “ Approach for Applying the Upper Prediction Limit to Limited Datasets ” (docket item number EPA

- HQ

- OAR

- 2010

- 1041

- 0 331 ) for the updated approach for limited datasets).

83. Comment : One commenter (1041

- 0080) re calculated the MACT floors for COS, eliminating all synthetic area sources (all USG sources), sources that share common controls and a stack and were represented by one data point (Isolatek and USG

– Red Wing), and measured emissions data that were below

- M DL (Thermafiber). The commenter’s rationale for eliminating these facility data is described in the comment summaries for HF and HCl in comment numbers 68
, 69 , and 70 . The same rationales summarized for HCl and HF in those comment summaries also apply to C OS. The commenter revised the MACT floor calculations for COS as follows:

Facility COS Emission Limit (lb/ton of melt)

Average of

Cupolas 99% UPL Existing Sources Multiplied Average by 2 Multiplied Average by 2.5 Multiplied Average by 3

IIG, Rock Wool, & Amerrock 2.915 10.439 5.83 7.2875 8.745

Response : As explained in section IV.A of the preamble to th e final rule and also in this response to comment document, w e are not adopting the numerical limits proposed on November 25, 2011 for COS from cupolas. As explained in our proposal on April 15, 2013, we are subcategorizing cupolas according to whether they use slag in the raw material introduced to the cupola, and are finalizing COS limits specific to these two different subcategories, as proposed in 2014. We also note that the commenter subsequently expressed support for the finalized COS emission limits for existing sources, as summarized in comment number 7 6

.

We disagree with the commenter’s recommended alternative calculations because they are not permissible under the CAA, as discussed in the EPA’s responses to comment numbers 68
, 69 , and 70 for HF and HCl. We note in those responses that the EPA cannot exclude synthetic area sources from the MACT analysis, the EPA must consider sources with shared stacks and can treat them as two distinct sources, and the EPA must account for measures of emitted HAP that are at or below the MDL.

D. Collectio n and Curing limits

84. Comment: One commenter (1041

- 0080/1041

- 0126/1041

- 0164) strongly supported the EPA’s combining curing and collection sources into a single source. The commenters also supported the EPA’s proposed three subcategories for that source (vert ical, horizontal, and drum) with respect to formaldehyde, phenol, and methanol emissions.

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Response: The a gency acknowledges the commenter’s support.

85. Comment: One commenter (1041

- 0164) strongly supported the proposed revised emission limits for formaldehyde , phenol, and methanol for both existing and new sources within the Curing and Collection Source Category, and in each subcategory (vertical, horizontal, and drum). In earlier comments, the same commenter (1041

- 0080) had suggested the EPA’s 2011 proposed

e mission limits on formaldehyde, phenol, and methanol were unnecessarily stringent, unreasonably costly, and not achievable in some cases. The commenter had recommended the following alternative emission limits for formaldehyde, phenol, and methanol in each of the proposed subcategories:

Design Pollutant Proposed Emission Limit (lb/ton of melt) Recommended Emission Limit (lb/ton of melt)

Vertical collection plus curing oven Formaldehyde 0.46 1.2

Phenol 0.52 0.60

Methanol 0.63 0.70

Horizontal collection plus curing oven Formaldehyde 0.054 0.5

Phenol 0.15 0.3

Methanol 0.022 0.1

Drum collection plus curing oven Formaldehyde 0.067 0.67

Phenol 0.0023 0.70

Methanol 0.00077 0.23

Vertical Collection The commenter noted the following issues related to the proposed vertical collection subcategory:

• Very limited emissions data were available for the collection chamber. E ngineering data from each of two inlet ducts to the filter house were provided

.

• For phenol and methanol, the EPA correctly summed the tw o data points. However, for formaldehyde, it appeared the EPA incorrectly averaged the two points. Representatives from facilities in the vertical collection subcategory have discussed this matter with EPA and it has been acknowledged that indeed this misc alculation did occur.

• The EPA’s proposed limits would necessitate installation of additional control technology, which, as noted earlier, is inconsistent with the EPA’s stated position.

• The commenter urged a liberal application of variability factors to account for very likely fluctuations in emissions given the very limited actual data.

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Horizontal Collection The commenter noted the following issues related to the proposed horizontal col lection subcategory:

• This is a small data set

– limited in volume, time, and season

– and application of a liberal variability factor is absolutely essential to insure the company can meet emission limits without the installation of control equipment. New data are being collected for the EPA’s consideration.

• There are limited data on formaldehyde, phenol, and methanol. The data for phenol and methanol are limited to the BTEC data. Specifically, this facility has only 6 data points for methanol and 6 data po ints for phenol; it is new data, not historical. The formaldehyde data are similarly limited.

• Increasing the EPA’s limits is particularly important for this subcategory because the data for formaldehyde range from 0.73 lbs per ton of melt to lower numbers that are within the proposed limits.

• These data points do not reflect possible fluctuations due to weather changes.

Drum Collection The commenter noted the following issues related to the proposed drum collection subcategory:

• BTEC data were collected from the exhaust of the oven RTO and not the exhaust duct from the collection drum for this subcategory and were not properly collected. New data have already been provided to the EPA to show more reliable drum emissions, which the commenter has requested be u sed to set the MACT floor.

• The commenter emphasized the importance of the EPA applying variability factors.

• No plant worldwide, to the commenter’s knowledge, using a collection drum had previous emission testing done on its emissions. Therefore, the propos ed emission limits for formaldehyde, phenol, and methanol need to be modified.

Response: The a gency acknowledges the commenter’s support. Regarding the commenter’s earlier comment on the 2011 proposal, the subcategorization of bonded products and emission l imits had been based on the data available to the EPA from the voluntary survey industry conducted within the industry. In our November 25, 2011 proposal, we explained that the survey included requests for existing test data on cupolas, curing ovens and co llection operations as well as test data for most HAP metals, CO, PM, formaldehyde, methanol and phenol. We also explained that all 7 mineral wool manufacturing facilities submitted existing test data and in some instances for multiple years. We included a detailed explanation of our calculation of the MACT floors in the MACT Floor Analysis for the Mineral Wool Production Manufacturing Source Category (EPA docket item EPA

- HQ

- OAR

- 2010

- 1041

- 0019), which was placed in the docket for this rulemaking.

Following the November 2011 proposal, we evaluated comments and data we received on the proposed emissions limits for the drum and vertical collection and curing subcategories

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and in response we revised the MACT floor emission limits for formaldehyde, phenol and
met hanol for these two subcategories, and in our supplemental proposal on April 15, 2013, we corrected the MACT floor limits for these pollutants. We further revised the limits in our 2014 proposal based on the EPA’s updated approach for limited dataset and o n new test data received in response to our 2013 proposal. The EPA acknowledges the commenter’s more recent support on the 2014 proposed emission limits for the formaldehyde, phenol, and methanol being finalized for both existing and new sources within the Curing and Collection Source Category, and in each subcategory (vertical, horizontal, and drum).

E. Compliance Schedule

86. Comment: One commenter (1041

- 0164) supported the EPA's proposed compliance dates, including the three year compliance period for existing sources.
Response: The a gency acknowledges the commenter’s support.

F. Small Business and Economic Impacts

87. Comment: One commenter (1041

- 0080) observed that the mineral wool industry already responded to one Advanced Notice of Proposed Rulemaking and a Notice of Proposed Rulemaking (October 10, 2008) on residual risk and provided the EPA extensive emissions data. The commenter noted that the EPA concluded in the proposed rulemaking in 2007 that additional controls or requirements were not necessary.

Response: T he October 10, 2008 proposed rulemaking was based upon one source test data point from the National Emissions Inventory (NEI) from a facility that closed subsequent to that proposal. The EPA did not receive additional data during the comment period on whic h to support a no

- risk conclusion. Moreover, the Brick MACT issues, and the General Provisions vacatur were not addressed by that rule. For these reasons, EPA decided to collect new data from operating facilities to assess risks, and re

- propose a rule that addressed the other MACT amendments identified by recent litigation referenced above.

88. Comment : One commenter (1041

- 0080, 1041

- 0126) disagreed with the conclusions of the EPA’s economic impact analysis on both the November 25, 2011 and April 15, 2013
prop osed rules. Specifically, the commenter believed some companies may have to install incinerators or wet or dry scrubbers to meet the emission limits, and the cost of additional control would be unaffordable by the companies and they would be forced out of business. The commenter expressed concern that when the EPA considered the economic impact of the proposed rule, it did so under the erroneous assumption that no new additional controls would be
necessary.
The commenter argued that an independent analysis of the proposed 1999 standards conducted by Price Waterhouse for the industry association estimated that the capital cost of installing an incinerator would be equal to three years of income and equal to 25 percent of the assets of a rock and slag wool fac ility. (A copy of the study was attached to comment letter 1041

- 0080.) The commenter reported that the study also estimated that the ratio of control costs to pre

- tax profits would range from 94.9 to 118.5 percent depending on the elasticity of demand for non

- bonded products. The commenter reported that the study concluded that the economic

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impact would be substantially reduced if cupola incinerators were not needed to meet the standards. The commenter argued that the costs of wet and dry scrubbers would ha ve similar impacts. The commenter stated that the study was not updated to address the impacts of the 2013 proposed rule, but argued that the overall impacts estimated in 1999 would still be applicable to the 2013 proposed rule.

The commenter argued that the technology needed to meet the emission limits proposed in 2011 and 2013 would cause the closure of some existing facilities. The commenter argued that the legislative history of the CAA indicates that MACT standards were not intended to force the shutd own of facilities. 26

The commenter also argued that controls needed to achieve the proposed limits would not be cost effective, and would be unreasonable based on earlier EPA findings that costs above a specified dollar amount per ton are unreasonable. 27 Th erefore, according to the commenter, the EPA should modify the proposed emission limits to avoid requiring additional control equipment, as done in other NESHAP, especially with respect to emissions of COS. The commenter argued that the EPA should not thre aten the existence of the mineral wool industry over the control of COS, which the commenter argued is naturally produced in abundance.

The commenter noted that the controls needed to meet the proposed limits, particularly incineration, would also create s econdary emissions of NO x and SO 2 , and that these would offset the emission reductions and also offset the environmental benefits of mineral wool products. The commenter noted that SO 2 has also been targeted by the EPA with a vigorous program of reduction. The commenter also argued that installation of control equipment would increase energy consumption for mineral wool companies, and thus increase greenhouse gas production.

Finally, the commenter argued that the mineral wool industry itself provides economic benefits in creating domestic employment opportunities and creating a quality product to meet both domestic and international markets, instead of relying on lesser

- qualit y foreign products.

Response: Section 112(d) of the CAA requires the EPA to promulgate standards for major sources of HAP based on the performance of the MACT. For existing sources, MACT standards must be at least as stringent as the average emissions limitation achieved by the best performing 12 percent of exi sting sources (for which the Administrator has emissions information) or the best performing 5 sources for source categories with less than 30 sources, as is the case here. For new sources, the MACT standards must be at least as stringent as “the emission control that is achieved in practice by the best controlled similar source.” 42 U.S.C. section 7412(d)(3). The EPA is precluded from considering costs in determining the minimum stringency of the MACT standards ( National Lime Ass’n v. EPA , 233 F.3d at 640 ), but the EPA

26 The commenter cited, H.R. Rep. No. 101

- 490(I) at 335 (1990) (“MACT is not intended to . . . drive sources to the brink of shutdown.”) S. Rep. No. 101

- 228 at 152 (1989) (“Controls which are so expensive that they force closure of the source or would severely impair its continuation as an economic entity are not ‘available.’”

27 The commenter cited, 59 F ed. Reg. 25,387, 25,391 (May 16, 1994).

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must consider more stringent “beyond

- the

- floor” control options in which cost can be considered.

In the 2011 proposal (76 FR 72787), we explained that section 609(b) of the Regulatory Flexibility Act (RFA), as amended, requires the EPA to convene a SBAR Panel prior to publication of the initial regulatory flexibility analysis (IRFA) that an agency may be required to prepare under the RFA. We explained that an SBAR was conducted for the M ineral W ool P roduction source category along with site visits to two mineral wool facilities. As also explained in the 2011 proposal, the SBREFA directs federal agencies to use regulatory flexibility in setting standards that apply to small businesses. And under the RFA, the EPA may consider legal alternative s that result in lower impacts to the industry where there is a significant impact on a substantial number of small entities (SISNOSE).

We agree with the commenter that for some companies there were economic impacts associated with the November 25, 2011 pr oposed rule

, but we note that it was not SISNOSE. (76 FR 72810). In the 2011 proposal, therefore, to the extent allowed under CAA section 112, we considered the SBAR panel recommendations, and these were reflected in the proposed subcategorization of colle ction and curing processes ( CAA section 112(d)) and the proposed compliance deadlines ( CAA section 112(i)). The EPA proposed three subcategories based on the industry identified collection and curing processes used in the U.S. mineral wool industry to prod uce bonded products, which are: vertical, horizontal and drum collection and curing. In response to comments such as this one, we obtained additional information on the raw materials and design of cupolas in the mineral wool industry that was not included in the voluntary ICR on which the November 2011 proposed rule was based. We then proposed additional subcategories for compliance with the HF and HCl numeric limits in our April 15, 2013 proposal. At that time, we again found that there was no SISNOSE. (78 FR 22391).

As explained in the 2014 proposal (79 FR 68025), we revised the emission limits for horizontal collection and curing operations, based on additional test data received, and the associated cost impacts. We performed an economic impact analysis for mineral wool consumers and producers nationally, using the annual compliance costs estimated for this proposed rule, and we again found that there was no SISNOSE. (79 FR 68029).

The EPA is finalizing the standards as proposed in 2013 and 2014. As shown in section III.F of the preamble to the final rule

, there is no SISNOSE and we believe the overall economic impact of the final rule is expected to be low on the affected industries and their consumers.

89. Comment: One commenter (1041

- 0080) expressed concern over the economic impacts from the EPA’s 2011 proposed rule on the mineral wool industry. The commenter disagreed with the EPA’s conclusion that the 2011 proposed emission limits would not necessitate any additional controls. The commenter stated that the majority of the industry could not meet some of the emission limits without installing additional air pollution controls, with capital cost estimates on possible controls ranging between $3 million to $6 million. According to the commenter, the remaining companies were concerned over their ability to consistently meet the emission limits going forward. In addition, according to the commenter, the investment to collect data and complete the research necessary to predict emission levels of HF and HCl for the different raw material combinations and fuel sources would cost the industry hundreds of

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thousands of dollars. The commenter expressed concern that given the current economic conditions, forcing mineral wool companies to install additional equipment likel y would result in many companies going out of business. The commenter contended that the economic downturn has been particularly severe for these companies since the building industry is experiencing the greatest downturn since building growth measurements were first taken in the 1950s.

The commenter agreed, in general, with the EPA’s characterization of the mineral wool industry, but corrected the EPA’s estimate of the facilities that are small businesses, and stated that five of the 7 facilities are owned by small businesses, and five of the six companies in the mineral wool source category are small businesses. The commenter pointed out that mineral wool industry has been reduced by more than half since the implementation of the Mineral Wool MACT in 1999. In addition, stated the commenter, many of the surviving plants have reduced the number of operating cupolas or production lines. Also, the commenter stated, no new mineral wool production facilities have started operations since the promulgation of the M ineral Wool MACT Standard, and two companies have changed owners. The commenter pointed out that the reduction in facilities and shut down of production lines are a permanent loss in industrial capacity and a permanent reduction in pollutant emissions.

The commenter (1041

- 0080) provided the following list of operating facilities in the United States:

Company Location Production Lines Date of Installation Bonded

- Product Nonbonded

- Product Amerrock Nolanville, TX 0 2 1986 Isolatek Huntington, IN 0 2 1929 IIG Phenix City, AL 1 1 1990 Rock Wool Mfg Leeds, AL 1 1 1970 Thermafiber Wabash, IN 1 1 1935 USG Walworth, WI 0 1 1969

USG Red Wing, MN 0 2 1973 1979 TOTAL 3 10

The commenter indicated that it had recently learned of the construction of a new mineral wool production facility by a company known as Armstrong and that the new facility would manufacture ceiling tile fibers, which the company had previously obtained fr om the now

- closed Sloss facility.

The commenter also recommended that the EPA should follow the recommendations of the Small Business Advocacy Review (SBAR) Panel that could effectively reduce the impact of the Proposed Rule on small businesses. The recom mendations highlighted by the commenter

were:

• The Panel recommended that the EPA propose amendments to the mineral wool MACT that offer regulatory flexibility to the maximum extent possible.

• The SBAR Panel observed that the EPA has flexibility in the avera ging method used for calculating the MACT floor and could use one of several averaging methods.

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Consistent with the SBAR Panel’s admonition to “offer regulatory flexibility to the maximum extent possible,” the commenter strongly urged the EPA to use the

av eraging method that accurately reflects the floor level of performance, but minimizes cost impacts on affected sources. The commenter argued that the manner in which the EPA calculated the 2011 proposed limits created limits that the majority of the facili ties could not meet, and, in many instances, may not be met on a consistent basis by the facilities on which the EPA based their calculation.

• The Panel recommended subcategorization wherever appropriate. The commenter strongly endorsed the EPA’s subcategor ization of the collection and curing sources, and requested subcategorization of the cupolas. (In response to the EPA’s proposed revisions in 2014 (79 FR 68025), the commenter ( 1041

- 0164 ) supported the EPA’s final subcategories for cupolas.)

• The Panel reco mmended setting MACT limits for new sources equal to MACT limits for existing sources. The commenter supported the EPA proposing identical limits for HF and HCl for new and existing sources, and requested that the EPA set identical limits for new and exist ing sources for COS.

• The Panel recommended the maximum amount of compliance time (3 years) for existing sources. (In response to the EPA’s proposed revisions in 2014 (79 FR 68025), the commenter ( 1041

- 0164 ) supported the EPA’s proposal to allow a 3 year

co mpliance period for existing sources.)

• The Panel recommended modifications for affirmative defense requirements to address malfunctions that reflect changes made in other Section 112 rules, and to provide guidance on complying during startup and shutdown.

Response: As previously explained, i n the 2011 proposal (76 FR 72787), we explained that section 609(b) of the RFA, as amended, requires the EPA to convene a SBAR Panel prior to publication of the IRFA that an agency may be required to prepare under the RF A. We explained that an SBAR was conducted for the mineral wool production source category along with site visits to two mineral wool facilities. We also explained that the SBAR panel is required to report findings on four key items that the EPA is to cons ider when completing the draft of the proposed rule. The Panel’s report addressing these key items has been placed in the docket for this rulemaking.

Under the RFA, the EPA may consider legal alternatives that result in lower impacts to the industry where there is a SISNOSE. As also explained in the 2011 proposal, the SBREFA directs federal agencies to consider using regulatory flexibility in setting standards that apply to small businesses. In the 2011 proposal, therefore, to the extent allowed under CAA s ection 112(d), we considered the SBAR panel recommendations, where possible, and these are reflected in the proposed subcategorization of collection and curing processes and the proposed compliance deadlines. The EPA proposed three subcategories based on t he industry identified collection and curing processes used in the U.S. mineral wool industry to produce bonded products, which are: vertical, horizontal and drum collection and curing. In response to comments on our November 2011 proposal, and after our r eview of additional data, we proposed in November 2013 two different subcategories for cupolas: open

- top and closed

- top cupolas. We

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also proposed a 3

- year compliance deadline for existing sources. As explained in the earlier response, none of the proposals resulted in a SISNOSE.

As also explained earlier, CAA section 112(d) requires the EPA to promulgate standards for major sources of HAP based on the performance of the MACT. For existing sources, MACT standards must be at least as stringent as the average emissions limitation achieved by the best performing 12 percent of existing sources (for which the Administrator has emissions information) or the best performing 5 sources for source categories with less than 30 sources, as is the case here. For new sourc es, the MACT standards must be at least as stringent as “the emission control that is achieved in practice by the best controlled similar source.” 42 U.S.C. section 7412(d)(3). The EPA is precluded from considering costs in determining the minimum stringency of the MACT standards ( National Lime Ass’n v. EPA , 233 F.3d at 640), but the EPA must consider more stringent “beyond

- the

- floor” control options in which cost can be considered. Thus, the EPA is prohibited from adopting the same standard for ne w sources as for existing sources, as recommended by the commenter, where the available data indicate that new sources can achieve a more stringent level of control, which is the case here.

We also note that the impacts of the 2014 proposed rule to mineral wool producers, which are associated with conducting performance tests, are estimated to be $48,800 (2013 dollars) for the whole industry, and range from 0.006 percent to 0.1 percent, expressed as annual compliance costs as a percent of sales. 28 The price elasticity of demand for the mineral wool industry is estimated at

- 0.8 29 , and the price elasticity of supply for the industry is estimated at

- 0.7. 30 With the responsiveness of mineral wool demand and supply to be less in percentage terms than the ch ange in product price as approximated by the cost to revenue ratio, since this ratio is the maximum price change that producers may face, and with this ratio at or below 1 percent for the majority of production from this industry, it is expected that miner al wool price and output changes in response to this final rule will be less than 1 percent. 31 Given these estimates of expected impacts, the EPA believes there is no SISNOSE and has so certified in the preamble to the final rule.

G. Environmental Benefits

90. Co mment: One commenter (1041

- 0080) stated that insulation has provided fundamental and very pragmatic health benefits. The commenter emphasized that rock and slag wool insulation resists mold, fungi, and bacteria growth because the material is inorganic. The commenter observed that the industry’s products also offer enhanced protection against

28 Use of this metric for economic impacts when small businesses are prevalent in an industry affected by a regulation is consistent with the EPA guidance on SBREFA compliance ( http://www.epa.gov/sbrefa/documents/Guidance

- RegFlexAct.pdf ), chapters 2 and 3.

29 Ho, M. S, R. Morgenstern, and J. S. Shih. 2008. “Impact of Carbon Price Policies on US Industry.” R FF Discussion Paper 08

- 37. Http://Www.Rff.Org/Publications/Pages/Publicationdetails.Aspx?. Publicationid=20680. Accessed August 2009. Table 8.A.6.

30 Broda, C., N. Limao, and D. Weinstein. 2008b. “Export Supply Elasticities.” <http://faculty. chicagobooth.e du/christian.broda/website/research/unrestricted/TradeElasticities/ TradeElasticities.html.>

31 This conclusion is consistent with perfect competition for this industry. This conclusion may change somewhat to the extent that this industry is imperfectly com petitive.

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damaging moisture infiltration that can rob insulation of R

- value. Other advantages of rock and slag wool insulation offered by the commenter are:

• Thermal performance

– mineral wool achieves higher R

- values than other insulation products; higher R

- values mean greater insulating power, translating into increased
year

- round comfort and more significant energy savings;

• Fire protection and life safety

- mineral wool product s lend enhanced fire protection to buildings and structures;

• Energy conservation

- mineral wool makes buildings more energy efficient, in a highly cost effective manner, and reducing GHG and other emissions;

• Waste reduction

- Slag wool is made from blast

- furnace slag, a waste by

- product of steel manufacturing, and consumes less energy during production than using entirely natural rock. Many insulation manufacturers are also reducing process waste by re

engineering manufacturing to incorporate production sc rap back into the primary production process, or reprocessing it into other products.

Response: We acknowledge the comment.

H. Surrogacy

91. Comment: One commenter (1041

- 0080) noted that the EPA specifically requested comments on the a gency decision to discontin ue use of formaldehyde as a surrogate for phenol and methanol (as well as a direct measure of formaldehyde emissions) and the use of CO as a surrogate for COS. The commenter and its members supported the EPA’s decision to abandon a surrogate for COS. With the development of EPA Test Method 318 for COS, the measurement will be a more accurate reflection of the actual COS emissions. While there is a correlation between CO emissions and formation of organic HAP emissions, COS is a single HAP, not multiple HAP like the metals, and the commenter argued that testing directly for that one HAP is preferable.

The commenter also supported the EPA’s decision to retain PM as a surrogate for the various metals that may be present in trace amounts in the mineral wool proc ess. Specifically, there are various metals that have an identified presence in mineral wool emissions, but the volume is so miniscule that to test for each metal seems counterintuitive, and, given that the majority of mineral wool manufacturers are small businesses, the commenter noted that it also seems unnecessarily costly when the emissions can just as effectively be monitored with one test for particulate matter. The commenter also noted that, a s acknowledged by the EPA, the courts have held that PM is an appropriate surrogate for HAP metals. 32

The commenter urged the EPA to retain formaldehyde testing as a surrogate for phenol and methanol for the same reasons PM data is more efficient than multiple tests for separate metals.

32 76 Fed. Reg. at 72,775 (citing Sierra Club v. EPA , 353 F.3d 976 (D.C. Cir. 2004)).

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Response: We acknowledge th e commenter’s support for our decision to discontinue the use of CO as a surrogate for COS and the continued use of PM as a surrogate for metals. However, as further discussed in section IV.C.4 of the preamble to the final rule, we disagree that formaldeh yde should be retained as a surrogate for phenol and methanol because the control device does not necessarily achieve the same reduction in all three pollutants.

I. Testing and monitoring Issues

92. Comment: One commenter (1041

- 0080/1041

- 0164) supported the EPA's proposed performance test schedule and the modified performance test methods. The commenter also supported the EPA’s proposed changes that require electronic notification, recordkeeping and reporting requirements.

Response: The a gency acknowledges the commenter’s support.

J. Miscellaneous

93. Comment : Commenter (1041

- 0126) identified a correction in the record for the EPA regarding the acronym for their organization. The EPA erroneously identified NAIMA as the National Association of Insulation Manufacturers of America. The correct identification is the North American Insulation Manufacturers Association.

Response: We appreciate the commenter pointing out this error on our part. The EPA regrets this error and will correct it in the final rule.

94. Comment : One co mmenter (1041

- 0126/1041

- 0164) argued that the EPA should delist COS from the CAA section 112 list of HAP based on three findings: no adverse health effects have been attributed to COS, no evidence of carcinogenicity exists, and no data supporting chronic t oxicity have been reported to date. The commenter (1041

- 0164) also argued that there is no evidence that COS presents a risk to the environment, that COS is naturally present in the atmosphere, and that 43 percent of emissions are from natural sources and 35 percent derives from atmospheric transformation of carbonyl disulfide (CS 2 ) to COS. The commenter argued that all worldwide anthropogenic sources account for only 4 percent of total COS levels, and that U.S. mineral wool manufacturing accounts for only a small fraction of these emissions. The commenter also argued that mineral wool provides environmental benefits that increase energy efficiency that reduces emissions from other sources.

Response: The issue of delisting COS from the HAP list is outside th e scope of this rulemaking. However, we invite the commenter to petition the EPA to delist COS. In order to do so, the petitioner is required to provide data showing that COS is not toxic. The absence of health effects data for any HAP is not the same as d ata showing no adverse health effects.

95. Comment : The commenter’s (1041

- 0126) stated that significant environmental and public health benefits are realized by the use of mineral wool, and requested that the a gency’s decisions and actions regarding the standa rd reflect the need to preserve and protect the mineral wool industry as a U.S. business that supplies the insulation market without resorting to foreign markets.

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Response: This comment is outside the scope of CAA section 112. The EPA’s mission in regard t o this MACT rule is to establish emission standards for all HAP emitted by sources in the mineral wool industry.

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VI. WOOL FIBERGLASS MANU FACTURING SOURCE CAT EGORY

A. Issues Related to Both Major and Area Sources

1. C hromium Emission Limits for Gas

- F ired Glass

- Melting Furnace s 96. Comment : One commenter (1042

- 0300/1042

- 0348) opined that the EPA should increase the chromium emission limits for oxyfuel furnaces and allow such furnaces to emit 4.6E

- 4 lb hexavalent chromium per ton of glass because this would not adversely impact the wool fiberglass industry. The commenter further believes this emission limit would present an acceptable risk as has been accepted in other RTR rules.

Response : We have reviewed the available chromium test data and information provided in comments received in response to our 2011, 2013, and 2014 proposals (76 FR 72770, November 25, 2011; 78 FR 22370, April 15, 2013; and 79 FR 68011, November 13, 2014), and based on this information we are revising the emissions limit for total chromium in this final rule. One such comment indicated that a newly

- rebuilt furnace, which we believe is the likely compliance technology, may not be able to demonstrate compliance with the proposed emission limit. The comment was based on one specific example fro m 2012 test data that showed a 1

- year old gas

- fired glass

- melting furnace emitting 0.00025 pounds chromium per ton of glass. We also reviewed comments and information, such as this one, and are revising the estimated costs of rebuilding the furnace as an o ption to comply with the chromium limit. We note that EPA may consider cost in revising emissions standards under CAA section 112(d)(6). ( Ass'n of Battery Recyclers v. EPA , 716 F.3d 667, 673 (D.C. Cir. 2013)

. We also note in section VIII.D.1 of the preamble to the final rule that rebuilding the furnace has a reasonable cost per pound of emissions reduction. Given the fact that the 2.5E

- 04 emissions level is achievable and cost effective, and results in lower ch romium emissions and lower risk, the EPA sees no reason to set the limit at a higher level. Thus, in the final rule, EPA is establishing a total chromium compound limit of 2.5E

- 04 pounds per ton of glass pulled

.

N ote that the HAP listed for regulation is c hromium compounds, and is not limited only to the hexavalent species of the pollutant. The EPA is establishing a chromium limit that applies to total chromium compounds.

As further discussed in sections VI.A and B of the preamble to the final rule regardin g major sources, and in sections VII of the preamble to the final rule regarding area sources, we have reviewed the available chromium test data and information provided in comments received in response to our 2011, 2013, and 2014 proposals (76 FR 72770, N ovember 25, 2011; 78 FR 22370, April 15, 2013; and 79 FR 68011, November 13, 2014), and based on this information we are revising the emissions limit for total chromium in these final rules. Based on comments we received in response to the proposed chromiu m compounds limits for gas

- fired glass

- melting furnaces the November 2014 supplemental proposal, we reviewed the cost and control options and found using new cost information that the limit, as proposed, was not as cost effective as we initially believed.

One such comment indicated that a newly

- rebuilt furnace, which we believe is the likely compliance technology, may not be able to demonstrate compliance with the proposed emission limit. The comment was based on one specific example from 2012 test data th at showed a 1

- year

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old gas

- fired glass

- melting furnace emitting 0.00025 pounds chromium per ton of glass. We also reviewed comments and information, such as this one, and are revising the estimated costs of rebuilding the furnace as an option to comply wit h the chromium limit, as discussed in section VI.B of the preamble to the final rule.

For major sources in this source category, consistent with the legislative history on CAA section 112(f)(2), and as discussed in sections IV and V of the preamble to the final rules, we conduct our risk assessment in two steps. The first step in the process of evaluating residual risk is the determination of acceptable risk. If risks are unacceptable, the EPA cannot consider cost in identifying the emissions standards nec essary to bring risks to an acceptable level. The second step is the determination of whether standards must be further revised in order to provide an ample margin of safety to protect public health. The ample margin of safety is the level at which the sta ndards must be set, unless an even more stringent standard is necessary to prevent, taking into consideration costs, energy, safety and other relevant factors, an adverse environmental effect.

As discussed in sections IV and V of the preamble to the final rules, in assessing risk for the major sources in the Wool Fiberglass Manufacturing source category, we found that risk was acceptable. In our ample margin of safety analysis we determined that a chromium limit was necessary to provide an ample margin of safety. To establish the level of the chromium limit, we considered costs and economic impacts, technological feasibility, and other factors.

Also for major sources in the Wool Fiberglass Manufacturing source category, we note that EPA may consider cost in revising emissions standards under CAA section 112(d)(6). ( Ass'n of Battery Recyclers v. EPA , 716 F.3d 667, 673 (D.C. Cir. 2013). We also note in section VI.B of the preamble to the final rule that rebuilding the furnace has a reasonable cost per pound of emissions reduction. For our technology review conducted under CAA section 112(d) (6), in reviewing advancements and new technology; we consider cost, availability, transferability, and other factors of all relevant new technology as well as improvements in technology since the time that the MACT standard was last amended. Our analysis is explained in section VI of the preamble to the final rule, and in the Technology Review Memo for the Wool Fiberglass Manufacturing source category.

For area sources in the wool fiberglass manufacturing source category, consistent with the legislative history on CAA sections; in the Urban Air Toxics Strategy (Strategy) as defined by CAA sections 112(d)(5), (c) (3) and (k), in determining GACT, we may consider costs and

ec onomic impacts, in addition to considering technical capabilities of the facilities and the availability of control measures. This is particularly important when developing regulations for source categories ...when determining whether additional control is n ecessary for sources with emissions that are already well controlled as a result of other existing or applicable standards. (Senate Report Number 101

- 228, December 20, 1989).

We determined that it was appropriate to modify the proposed limit of 6.0E

- 5 pou nds per ton of glass pulled because the cost effectiveness for the emission reduction options ($660,000 per pound of chromium reduced for the raw material substitution option, and $620,000 per pound chromium reduced for the furnace rebuild) were not reason able compared to other cases where the EPA has regulated highly toxic pollutants, such as hexavalent chromium. We therefore

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reviewed the data to determine whether a higher limit than previously proposed would be more cost effective while still significantl y reducing chromium emissions from wool fiberglass gas

fired glass

- melting furnaces. The EPA found that most wool fiberglass gas

- fired glass

- melting furnaces at major sources currently emit chromium compounds at rates below 2.5E

- 04 pounds chromium per ton of glass pulled. We compared the chromium emission reductions that would have resulted under the previously proposed emission limit of 6.0E

- 5 pounds chromium per ton of glass pulled to the reductions that result from the final limit of 2.5E

- 04 pounds chrom ium per ton of glass pulled. We found that the proposed limit would have reduced chromium from major sources by 567 pounds per year, and that the final limit reduces chromium by 524 pounds per year. Because these emissions reductions are comparable, we fin alized the emission limit for 2.5E

- 04 pounds chromium per ton of glass pulled for gas

- fired glass

- melting furnaces located at wool fiberglass facilities. Given the fact that the 2.5E

- 04 emissions level is achievable and cost effective, and results in lower chromium emissions and lower risk, the EPA sees no reason to set the limit at a higher level. Thus, in the final rule, EPA is establishing a total chromium compound limit of 2.5E

- 04 pounds per ton of glass pulled.

Note that the HAP listed for regulation i s chromium compounds, and is not limited only to the hexavalent species of the pollutant. The EPA is establishing a chromium limit that applies to total chromium compounds.

97. Comment: Two commenters (1042

- 0120 and 1042

- 0115/1042

- 0120/1042

- 0300/1042

- 0348) req uested that the EPA treat furnace K2 at Certain T eed’s Kansas City facility as an outlier. The commenters (1042

- 0120; 1042

- 0126) stated that the EPA is attempting to subject the entire industry either to the existing MACT and new area source standards based on a single facility’s test results showing high hexavalent chromium emissions from one of several types of furnaces used in the industry, which is an oxyfuel melter. According to the commenters, this approach was flawed, as was the EPA’s understanding of the facts, and the approach lacks sound scientific support for its proposed regulation.

One commenter (1042

- 0115/1042

- 0120/1042

- 0300/1042

- 0348) observed that the EPA acknowledged during the August 31, 2011 meeting that, but for this one test result

– Cert ainTeed, Kansas City

– chromium emissions from this industry would not be a concern on the part of the agency. The commenter agreed with this characterization and urged the EPA to treat this result as an outlier and deal with it accordingly without implica ting the entire wool fiberglass industry. The commenter contended that the EPA should either reject the outlier entirely from the dataset or address it in a separate action from the RTR for the wool fiberglass industry. The commenter argued that the EPA, i n deciding that these furnaces are not outliers, has not considered key information about the furnaces indicating that they are outliers (i.e., design and raw material variation). The commenter believed additional data would support a conclusion that the h ighest emissions should be viewed as an outlier, and not as an industry

- wide concern. The commenter reserved the right to submit supplemental comments to provide additional analysis on this very point.

The commenter (1042

- 0115/1042

- 0120/1042

- 0300/1042

- 0348 ) continued that there is reason to believe that the CertainTeed data are either flawed (because emissions from this facility are so much greater than emissions from other tested facilities) or at least are not representative of the industry as a whole, an d that a separate subcategory should be established for this facility

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to assure that it (and the industry as a whole) is appropriately regulated. The commenter argued that it should be evident that because the second highest emission data point is less tha n two percent of the outlier from CertainTeed’s Kansas City, Kansas furnace, the CertainTeed data point is not statistically significant when viewed in the context of all hex avalent chrom ium emi tted from the industry , and should be treated as an outlier.

Response : We disagree with the comment. As explained in our April 2013 proposal, w e issued a CAA section 114 ICR in December 2012, requesting test data on total chromium compounds emissions from all glass

- melting furnaces and we were able to confirm our view of chromium emissions from this source prior to our April 2013 proposal. In our November 2014 proposal, we al so explained that as part of the data collection effort associated with this rulemaking, we collected source test data on 14 furnaces with information on furnace age, last rebricking or repair dates, current furnace age, and anticipated or planned future f urnace replacement. We also explained that we had obtained emissions data for repeat ed testing of three rebuilt gas

- fired glass

- melting furnaces. We further explained that of the 14 tested furnaces, all four furnaces over 12 years old exceeded the proposed chromium limit. Of the 10 furnaces under 12 years old, three exceeded the limit (one only marginally), and seven tested in compliance with (i.e., below) the proposed chromium limit. (79 FR 68021). See also 72 FR 22379

- 82 for our discussion of the test dat a the a gency used to support the proposed chromium compounds limit.

As part of our data gathering exercise, we carefully reviewed each test report conducted for this industry and discussed the results with company operators. We learned through that
process that, although the Kansas City K2 emitted in 2012 at extremely high levels, when the furnace was less than two years old, chromium emissions measured on the same scale as other newer furnaces in this industry currently measure. We also confirmed that chro mium emissions increase with furnace age as the refractories age, and that the type of furnace at the high emitter is an emerging new technology that is preferred across the industry where a source of industrial oxygen is economically available. As explain ed in section VI.B of the preamble for the final rule, we view this as a “development in practices, processes and control technologies” for this source category and are therefore, promulgating the chromium compounds limit under CAA s ection 112(d)(6). The r esults of our technology review can be found in the Section 112(d)(6) Technology Review for Wool Fiberglass NESHAP memorandum, which is in the docket for this rulemaking.

As explained earlier, we did obtain test data subsequent to the test data that this

c ommenter describes as an “outlier.” We also note that when we conducted our review of the data, we learned that the company operator knew the emissions of chromium compounds were very high, that the source of the chromium was the refractory lining of the f urnace, and that the emissions of chromium increased with furnace age. Only the amount of chromium that was in the hexavalent state (93 percent) was new information to the operator. As also explained in our November 2014 proposal, w e also learned at indust ry meetings, and from our CAA section 114 data collection, that most wool fiberglass furnaces are constructed using similar high

- chromium refractories, and that gas

- fired (oxyfuel and air

- gas) furnaces have the greatest potential to emit chromium compounds because they have the internal temperature, the availability of oxygen, reactivity, and corrosivity of the furnace environment that are typical of wool fiberglass furnaces. (79 FR 68021).

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As explained in the November 2011 proposal, under the second step of the risk assessment, under CAA section 1 12( f )( 2), the EPA also considers whether existing risk can be lowered, and considers the cost of those reductions. This second step of the analysis is also known as an ample margin of safety analysis. We are also finalizing the chromium compounds limit as a result of our ample margin of safety analysis. This is because in our April 2013 proposal, we also explained that we have no reason to believe the exact process that was found at the Kansas City, Kansas facility could not be replicated at any wool fiberglass manufacturer elsewhere, and we continue to believe that the test results at issue are simply indicative of the potential chromium (and hexavalent chromium) emissions that can result from the combination of ga s

- fired glass

- melting furnaces that are constructed using high

- chromium refractories. (78 FR 22379). In our April 15, 2013 supplemental proposal, we also explained that the elevated chromium emissions from gas

- fired furnaces are of concern due to the toxic nature of the type of chromium emitted ( hexavalent chromium ) and the effects associated with its inhalation. For example , we explained that hexavalent chromium inhalation is associated with lung cancer and that it is classified as a Class A known human ca rcinogen. (76 FR 22374). In our November 2011 proposal

, we explained that we had also performed an auxiliary risk characterization analysis to assess the potential maximum individual lifetime cancer risks in the event that all

w ool f iberglass m anufacturing facilities emitted at the level of the highest hexavalent chromium emitter. We also explained that the auxiliary risk analysis indicated that if other facilities were to emit at that high level, emissions of hexavalent chromium could potentially pose unac ceptable risks to public health due to inhalation exposures resulting from stack emissions of hexavalent chromium. This is because the results of the auxiliary analysis indicated that the estimated emissions from 14 facilities could lead to maximum individ ual lifetime cancer risks greater than 100

- in

- 1

- million, with the highest emitting facility posing a potential maximum individual risk of 900

- in

- 1

- million; 8,100 people would be exposed to risks greater than 100

- in

- 1

- million, 460,000 people would be expose d to risks of greater than 10

- in

- 1

- million, and over 7 million people would be exposed to cancer risks of greater than 1

- in

- 1

- million. The results of the auxiliary risk assessment were presented in Table 9 of the preamble, which can be found at 76 FR 72801

- 80

.

98. Comment : One commenter (1042

- 0299) challenged the EPA’s authority to exclude electric furnaces at major sources from regulation because CAA section 112(d) requires the EPA to set standards for all HAP emitted from the source category, and electric arc furnaces ar e part of the source category and emit chromium, albeit at lower levels than the gas

- fired furnaces. The commenter (1042

- 0299) argued that the EPA had not justified excluding electric furnaces from the definition of category. In the commenter’s (1042

- 0299) view, the EPA is not allowed to exempt electric

- only furnaces from regulation under the RTR because electric furnaces are part of the source category and because they emit chromium compounds, a HAP. Another commenter (1042

- 0300) agreed with the EPA’s deci sion to exclude electric furnaces from the rule because, in the commenter’s opinion, electric furnaces do not have the design features needed to emit high (or frequently even measurable) levels of chromium compounds, and therefore do not warrant regulation

. Response: In the final rule, we are promulgating an emission limit of 0.33 pounds of PM per ton of glass pulled that is applicable to all glass

- melting furnaces in the W ool F iberglass M anufacturing source category. Accordingly, the PM limit will apply t o electric furnaces at major sources as a surrogate limit for non

- mercury metal HAP. The EPA may use a surrogate to

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regulate HAP if there is reasonable basis to do so and in several rulemakings, we have used PM as a surrogate ‘‘for HAP metals because PM co ntrol technology traps HAP metal particles and other particulates indiscriminately.’’ National Lime v. EPA
, 233 F.3d at 639 . We continue to believe that PM controls would be effective for chromium emissions commensurate with the levels from both steel and electric furnaces used by wool fiberglass manufacturing facilities.

In response to comments on our November 2011 proposal, we proposed to limit the applicability of the chromium compounds standards to only gas

- fired glass

- melting furnaces in our April 2013 proposal (72 FR 22386). We also retained the PM limits for all glass

- melting furnaces that would include electric glass

- melting furnaces at major sources . We explained that electric furnaces emit metal HAP including chromium, albeit at generally lower emi ssion levels than gas

- fired furnaces. Our propos al was based on emissions test data collected for all furnace types at all facilities in the source category. As explained in the preamble to the 2013 proposal, furnace construction and source test data colle cted via CAA section 114 questionnaires show that electric furnaces are not constructed using high

- chromium refractories above the glass

- metal line, do not reach the temperatures necessary to transform chromium to the hexavalent state, and do not emit sign ificant amounts of chromium compounds, as do the gas

- fired furnaces. In fact, all test data for electric furnaces show that chromium emissions were below the detection limit or were at least one order of magnitude below the proposed limit. Refer to the pre amble discussion to the 2013 proposal (78 FR 22379

- 22382, April 15, 2013) for further discussion about the low potential for metal emissions from electric glass

- melting furnaces as compared to gas

- fired glass

melting furnaces. We have also provided a det ailed explanation on our decision to set both PM and total chromium standards in the memorandum “ Technical Basis for Separate Chromium Emission Limits for Wool Fiberglass Glass

- Melting Furnaces, ” which is in the docket for this rulemaking.

Therefore, we believe that PM controls for electric glass

- melting furnaces are an appropriate surrogate for all non

- mercury HAP metals

.

99. Comment: One commenter (1042

- 0120/1042

- 0300/1042

- 0348) argued that the EPA should not promulgate a chromium limit for wool fiberglass furnaces and that PM is a valid surrogate for all HAP metals, including chromium. The commenter (1042

- 0120) stated that non

oxyfue l furnaces should not have a chromium limit, but should be subject instead to a PM limit as surrogate for all non

- mercury metal HAP including chromium. The commenter noted that

non

- oxyfuel furnaces

– steel shell, cold

- top electric, air

- gas, and specialty

– have extremely low
to non

- detectable chromium emissions. The commenter referred to the summary spreadsheet setting forth the chromium content of refractories and chrom ium emissions (provided in Attachment 8 of comment letter 1042

- 0120) and the test report s sent to the EPA. The commenter continued that this summary spreadsheet establishes that oxyfuel furnaces are the furnaces that are more likely to have different chromium e missions. The commenter stated th at this conclusion will be substantiated by the da ta submitted through companies pursuant to the EPA’s CAA section 114 inquiry. The commenter stated that these data sets demonstrate that the other furnace types do not pose a chrom ium issue. Therefore, the commenter urged the EPA not to impose a chromium l imit for the other furnace types. The commenter argued that because PM limits will remain in place, a specific chromium limit for non

- oxyfuel furnaces is duplicative and certainly not justified by the EPA’s risk and exposure assessment for chromium emissio ns.

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The commenter (1042

- 0300/1042

- 0348) noted that in the original 1999 MACT standard, PM appropriately was considered a surrogate for all HAP metals. In the commenter’s opinion, the EPA should continue with this 1999 designation for this industry, as curr ently allowed by the courts. The commenter (1042

- 0120) stated that because the courts have recognized that PM is a valid surrogate for heavy metals, it should be retained as a surrogate for all heavy metals, including chromium.

The commenter (1042

- 0120) ar gued that, if the EPA were to retain a chromium limit, the EPA should not also retain PM as a surrogate.

Response: The commenter (1042

- 0300/1042

- 0348) is correct that we used PM as a surrogate for all non

- mercury metals in the 1999 NESHAP. The commenter, h owever, is incorrect in asserting that there is no justification for a PM limit if there is also a chromium limit. As explained earlier, the EPA may use a surrogate to regulate HAP if there is reasonable basis to do so. We have used PM as a surrogate to r egulate non

- mercury HAP metals when (1) “HAP metals are invariably present . . . in PM;” (2) “PM control technology indiscriminately captures HAP metals along with other particulates;” and (3) “PM control is the only means by which facilities achieve reduc tion in HAP metal emissions.” National Lime v. EPA

, 233 F.3d at 639. We have also always reasoned that “[i]f HAP metals are invariably present in ...PM, then even if the ratio of metals to PM is small and variable, or simply unknown, PM is a reasonable sur rogate for the metals

- assuming ... that PM control technology indiscriminately captures HAP metals along with other particulates.” Id

. As explained earlier, we are promulgating a PM standard that is applicable to all glass melting furnaces in the Wool Fibe rglass Manufacturing source category. Accordingly, the PM limit will apply to electric furnaces at major sources as a surrogate limit for

non

- mercury metal HAP.

I n response to comments on our November 2011 proposal, in April 2013 we proposed to limit the applicability of the chromium compounds limit to only gas

- fired glass

- melting furnaces (72 FR 22386) . As explained in our 2013 proposal, gas

- fired furnaces have a higher chromium emission potential due to their technical design and operation. For example, because they operate at higher temperatures, gas

- fired furnaces are constructed with chromium refractories at various parts of the furnace that are above the molten glass, including the crown. Temperatures above the melt in gas

- fired furnaces range from 2

, 500 to 4
, 500 ◦ F, and these temperatures are sufficient to convert chromium to its hexavalent state. When chromium is available, as it is in the refractories above the melt in gas

- fired furnaces, it may be converted to the hexavalent state by the heat of the gas

- fired furnace. Thus, gas

- fired furnaces have the potential to emit elevated levels of chromium, even when meeting the total PM limit. (78 FR 22379

- 82; 78 FR 22386). These higher chromium emissions do not occur with electric furnaces because they are c onstructed with either

non

- chromium refractories (cold

- top electric) or steel in place of refractories (electric steel shell) above the glass/metal line. As also explained in our 2013 proposal, available test data from both electric and steel shell glass

- m elting furnaces consistently showed chromium emission below the detection level of the emissions measurement method. (78 FR 22379

- 80). Retaining a PM surrogate without also requiring a chromium limit for gas

- fired furnaces (as in the 1999 MACT) would ignor e the new information we have obtained from industry regarding the potentially high chromium emissions from gas

- fired furnaces, and would not sufficiently reduce emissions of hexavalent chromium, a known human carcinogen, from these sources. For non

- gas

- fi red

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furnaces, as explained earlier, we continue to believe that the control devices used in the industry to reduce emissions of PM are effective for all non

- mercury HAP metals.

Therefore, we are finalizing a chromium emissions limit that is applicable to a ll gas

- fired furnaces in order to address the higher chromium emission potential for such furnaces, under both sections 112(d)(6) and (f)(2). We are also finalizing a PM limit to serve as the surrogate for all non

- mercury metal HAP for non

- gas

- fired furnac es and the surrogate for all non

- mercury and

non

- chromium metal HAP for gas

- fired furnaces, under section 112(d)(6).

100. Comment : One commenter (1042

- 0115/1042

- 0120/1042

- 0300/1042

- 0348) asked why a chromium limit is needed if recent air monitoring in Kansas Ci ty shows that the hexavalent chromium levels in air do not indicate a health concern.

Response: The monitoring mentioned by the commenter presents a short snapshot of time and may not be indicative of long

- term risk

. In addition, it is our understanding th at the monitoring was conducted during a time period when the furnace with the highest chromium emissions was shut down.

In section VI of the preamble to the final rule, we present our RTR results, which were conducted under both CAA sections 112(d)(6) an d (f)(2). As explained in the preamble for the final rule, we are promulgating the chromium compounds limit under CAA s ection 112(d)(6) because we have found that a “development in practices, processes and control technologies” for this source category. A dditionally, as also explained in the preamble to the final rule, we are finalizing the chromium compounds limit under the ample margin of safety step of CAA section 112(f)(2). The final rule requirements are b ased on information we have gathered from indu stry meetings and our CAA section 114 data collection, and we have established that most wool fiberglass furnaces are constructed using similar high

- chromium refractories as the Kansas City facility referred to by the commenter, that emissions of chromium increase with furnace age ( see the memorandum “Explanation of the Mechanisms of Chromium Emissions from Gas

- Fired Furnaces” in docket EPA

- HQ

- OAR

- 2010

- 1042 ), and that gas

- fired (oxyfuel and air

- gas) furnaces have the greatest potential to emit chromium comp ounds because they have the internal temperature, the availability of oxygen, reactivity, and corrosivity of the furnace environment that are typical of wool fiberglass furnaces. Based on these facts (as further discussed in section VI.B.3 of the preamble to the final rule)

, we have reason to believe that there is a potential for
gas

- fired furnaces to emit chromium at levels significant enough to potentially present a health risk to nearby populations in the absence of chromium air emissions limits. The aux iliary risk analysis performed as part of this rulemaking ( “Draft Residual Risk Assessment for the Mineral Wool Production and Wool Fiberglass Manufacturing Source Categories” and “Maximum Predicted HEM

- 3 Chronic Risks (Wool Fiberglass Manufacturing) based on Revised

– What If Analysis,” available in the docket for this rulemaking (EPA

- HQ

- OAR

- 2010

- 1042

- 0086 and EPA

- HQ

- OAR

- 2010

- 1042

- 0263, respectively ) specifically addressed health risks if the potential for high chromium emissions at other location s of wool fiberglass were realized, and these risks were found to be as much as 400

- in

- 1 million. Therefore, even if one were to accept that the actual monitoring data from Kansas City does not indicate a health concern, that fact does not mean that chromiu m emissions from furnaces are not a national health concern sufficient to warrant regulation

. We have also confirmed that chromium emissions increase with furnace age as the refractories age, and that the type of furnace at the high emitter is an emerging new

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technology that is preferred across the industry where a source of industrial oxygen is economically available.

2. PM Limit f or Glass

- Melting Furnace s 101. Comment : One commenter (1042

- 0120) argued that the EPA should not have proposed in 2011 to reestablish t he PM MACT floor for glass

- melting furnaces or use post

MACT compliance data. According to the commenter, the EPA issued new and existing source MACT standards for PM in 1999 and therefore, is not required to revisit those standards. The commenter contende d that the 1999 PM standards are valid MACT standards when PM is used as a surrogate for HAP metals. The commenter argued that, even if it were appropriate to otherwise revise the 1999 PM standards, the EPA has not provided an explanation or asserted
any r ational basis for choosing to calculate a new MACT floor and standard for PM, as opposed to using its discretion under CAA section 112(d)(6) to make an appropriate adjustment without recalculating the floor and standard.

The commenter added that nothing in CAA section 112(d) suggests that the EPA is required to establish a floor under CAA section 112(d)(3) more than once in issuing or revising MACT standards under CAA section 112(d). The commenter contended that the structure of CAA section 112(d) envisions the initial setting of new and existing source MACT standards that are no less stringent than the formulations set forth in paragraph (d)(3). The commenter noted that the EPA then is to revisit those standards every 8 years when it conducts its “technolog y review” under section CAA 112(d)(6), and determines whether it is appropriate to revise the standards. Moreover, according to the commenter (1042

- 0120), the U.S. Court of Appeals for the D.C. Circuit upheld the position that there should not be an inexor able downward ratcheting effect for the MACT floors in the challenge to the Hazardous Organic NESHAP rule. The commenter claimed that the EPA proposed exactly such a downward ratcheting of the floors by setting the floor for a second time and using data ga thered following compliance with the 1999 MACT standards. According to the commenter, the “new technology development” identified by the EPA exists as a result of industry having to comply with the 1999 MACT standard and that there are no new control techn ologies in use in this industry beyond those used to comply with the 1999 standard. The commenter argued that the EPA’s proposal uses test data that have achieved much lower emissions levels as a result of complying with the 1999 PM standards to
set more s tringent standards now, but that the CAA does not allow the EPA to drive down the floors as a result of using data from sources that already have installed MACT controls.

Response: In the 2011 proposal, the EPA had intended to set a PM limit that represent ed what we considered to be the demonstrated current performance of PM controls for the entire population of furnaces as part of the technology review performed under the authority of CAA section 112(d)(6). We explained that most sources had reported PM em issions that were less than 10 percent of the current limit with several sources achieving PM emissions that were two to three orders of magnitude lower than the current MACT limit. We reasoned that new furnace designs and improvements in control devices o perations, design and bags since the 1999 MACT promulgation were most likely responsible for reductions in PM emissions. However, a s explained in the preamble to the 2013 proposal (78 FR 22837), in reviewing comments related to the proposed PM limit, we re alized that we had erred in calculating the 2011 proposed PM limit based on the best performing 12 percent of the sources

, and we proposed a revised PM limit of 0.33 pounds per ton of glass pulled based on the level achieved by well

- controlled units that w e

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evaluated, not based on recalculation of the MACT floor. Recalculating the MACT floor would have been the correct approach if our intent had been to establish a MACT limit under CAA section s 112(d)(2) and (3), but that was not our intent. W e are finalizing the PM limit of 0.33 pounds per ton of glass pulled. This standard and t he results of our technology review, including our calculations

, can be found in the memorandum “Section 112(d)(6) Technology Review for Wool Fiberglass NESHAP

, ” which is in the docket for this rulemaking.

However, w e disagree with the commenter’s view that CAA section 112(d)(6) is the EPA’s sole authority for revising existing MACT standards. As a general matter, an agency remains free to revise improperly promulgated or otherwise unsupportable rules. Further, we believe that Portland Cement Ass’n v. EPA , 665 F.3d 177, 189 (D.C. Cir. 2011) confirms that the EPA is not constrained by CAA section 112(d)(6) and may reassess its standards more often, including revising exi sting floors if need be under the authority of CAA section s 112(d)(2) and (3). The commenter is, thus, incorrect that CAA section 112(d)(6) provides the exclusive authority to situations where (e.g., HCl and HF) the EPA did not adopt a proper MACT standard initially

.

102. Comment : One commenter (1042

- 0120) suggested that the PM limits proposed by the EPA in 2011 cannot be met by the majority of wool fiberglass manufacturing facilities (or the facilities are not confident they can meet the proposed PM limits on a consistent basis with the controls implemented to meet the original MACT limits), even with the controls that were implemented as a result of the initial MACT limits. The commenter provided a list of facilities that, based on the available data, cannot m eet the 2011 proposed PM emission limit for existing sources. The commenter stated that existing data provided to the EPA as part of the fiberglass industry’s voluntary data submission show the range for PM emissions as 0.0043

– 0.50 pounds per ton of melt (filterable PM only). The commenter opined that the EPA should retain the current PM limit of 0.5 pound per ton of melt.

Response: As discussed in the preamble to the 2013 proposal, we did not intend to propose a PM MACT floor limit in 2011. We intended t o develop a limit under CAA section 112(d)(6) based on the level achieved by well

- controlled units that we evaluated, not based on recalculation of the MACT floor. As noted in our response to comment number 10 1 , we corrected our error by re

- proposing a new PM limit in our 2013 proposal. Based on the PM data available to the EPA , all current furnaces can meet the final limit of 0.33 pounds per ton glass pulled. The results of our technology review including more information on the development of the PM limit can be found in the memorandum, “Section 112(d)(6) Technology Review for Wool Fiberglass NESHAP,” which is in the docket for this rulemaking.

103. Comment: One commenter (1042

- 0120) opined that because PM is not a HAP, the EPA lacks authority to regulate PM in a MACT standard except as a surrogate, and that the 2011 proposal did not indicate that the EPA was retaining PM as a surrogate for HAP in this rule.

Response: The EPA clarifies that the PM limit being finalized is a surrogate for non

mercury HAP metals. Refer to the EPA’s response to comment number 99 for a discussion of the EPA’s decision to finalize PM as a surrogate for non

- mercury metal HAP for major sources.

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104. Comment: One commenter (1042

- 0115f) recommended that the EPA minimize the use of surrogates in all related industries to avoid situations like Certain T eed’s K2 facility in Kansas.

Response: We disagree with the commenter regarding minimizing the use of surrogates. As outlined in our response to comment number 99
, we may use surrogates to regulat e HAP if there is a reasonable basis to do so. We do recognize, however, that in cases where a surrogate is not reasonable, we should regulate specific HAP as we are regulating chromium from gas

- fired furnaces in this final rule.

105. Comment: One commenter (10 42

- 0120) asserted that the EPA’s position that “synthetic area sources” may be considered in the floor determination for PM for this source category is unfounded because CAA section 112 expressly defines the terms “major source” and “area source” and provi des for separate listing and regulation of major sources and area sources, but that the statute does not distinguish between “area sources” and “synthetic area sources.” Therefore, the commenter contended that “synthetic area sources” are not part of a cor responding major source category and cannot be used in determining the MACT floors for the major source category. The commenter argued that the MACT floor should be recalculated using data from only sources that are currently subject to the MACT.

The comme nter provided a list of six area source facilities that the commenter argued should be eliminated from EPA’s MACT floor calculation for PM : Knauf’s Lanett, Alabama; Knauf’s Shasta Lake, California; Johns Manville’s Richmond, Indiana (7603); Johns Manville’ s Richmond, Indiana (7602); Johns Manville’s Willows, California; and Owens Corning’s Fairburn, Georgia.

The commenter noted that, in other MACT standards for other source categories , the EPA has not included true (or “natural”) area sources in establishi ng the MACT floor for PM. In the recent Portland Cement MACT, the commenter argued that the EPA conceded that it would be inappropriate to include true area sources in the MACT floor. See Office of Air Quality Planning and Standards, Development of the MAC T Floors for the Final NESHAP for Portland Cement, August 6, 2010 at 14 (“Subsequent to proposal, we received comments that indicated we had inappropriately (albeit inadvertently) included certain natural area sources in the MACT floor analysis.”). See als o 68 Fed. Reg. 26,690, 26,698 (May 16, 2003) (“EPA disagrees that the CAA contemplates that synthetic minor sources must be treated like true area sources and excluded from the MACT floor determinations.”) The commenter observed that EPA has interpreted th e Act to require inclusion of synthetic area sources in the MACT floor determination. See I d . (“We believe that the better interpretation of the CAA’s plain language and legislative history requires that synthetic minor sources be included in MACT floor de terminations.”)

The commenter stated that CAA section 112 expressly defines the terms “major source” and “area source” and provides that major sources and area sources must be separately listed and regulated. The commenter argued that the statute does not distinguish between “area sources” and “synthetic area sources” (i.e., an area source is an area source, regardless of whether emissions limitations or control requirements are needed). Therefore, the commenter argued that

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“synthetic area sources” are not part of a corresponding major source category and cannot be used in determining the MACT floors for the major source category.

Response: As discussed in the preamble to the 2013 proposal, w e did not intend to propose a PM MACT floor limit in 2011. We inten ded to develop a limit under CAA section 112(d)(6). As noted in our response to comment number 101
, we corrected our error and the PM limit is no longer based on a MACT floor calculation

. Moreover, and as explained in previously rulemakings ( e.g., Brick NESHAP, 68 FR 26697

– 26698, May 16, 2003) we believe that the better interpretation of the plain language of section 112(d)(3) and relevant legislative history requires that synthetic minor sources should be included in MACT floor determinations

.

106. Comment: O ne commenter (1042

- 0120) stated that five of the sources

– Guardian’s Albion, Michigan (counted as three sources for the MACT floor) and Johns Manville’s Richmond, Indiana (counted as two sources)

– are inappropriately used to set the MACT floor. The comme nter observed that Guardian’s Albion, Michigan facility is used as three sources for the MACT floor calculation. According to the commenter, this is problematic for a number of reasons: ( 1) one of three furnaces was not operating when the testing was condu cted; ( 2) the emissions from all three sources are emitted to one common exhaust point, so the testing sampling was collected from this one exhaust point; ( 3) EPA did not accurately identify the emissions from each furnace; and ( 4) after testing these furn aces under these conditions for years, the company could not accurately identify or predict the specific emissions from each furnace. The commenter claimed that to count one point source as three sources when the emissions from each furnace cannot be accur ately ascertained is incorrect. The commenter also stated that Johns Manville Richmond, Indiana facility is counted as two sources, but there is only one furnace at the Richmond, Indiana facility. The commenter contended that EPA should count Guardian’s Al bion, Michigan facility as one source, not three, and count Johns Manville’s Richmond, Indiana facility as one source, not two.

The commenter also contended that PM data from Guardian’s Albion, Michigan facility (counted as three sources); Johns Manville’ s Willows, California facility; Johns Manville’s Richmond, Indiana facility (counted as two sources); and Knauf’s Lanett, Alabama facility are below

- MDL, even though the data were generated from runs longer than the promulgated methods contemplate. The com menter requested that the EPA remove all seven of these sources from the calculation for the MACT floor because below

- MDL data is unquantifiable. The commenter expressed concern that using below

- MDL data is likely to set limits so stringent that the best p erforming sources cannot even meet those limits. The commenter cited a memorandum from RMB Consulting about relying on below

- MDL data. 33 According to the commenter, the EPA should only use values that are above the MDL, i.e., actual values, in calculating t he MACT floor. The commenter stated that the emissions floor must be determined by quantifiable data.

Response: As discussed in the preamble to the 2013 proposal and a s noted in response to comment number 101
, the PM limit is no longer based on a MACT floo r calculation

.

33 RMB Consulting & Research, Inc. Memorandum, Comments on Proposed EGU MACT Rule, July 19, 2011,
p. 18.

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107. Comment: One commenter (1042

- 0299) contended that standard developed under section 112(d) of the CAA must first meet the requirements of CAA sections 112(d)(2) and (3) for developing MACT standards, and that the provisions in CAA section 112 (d)(6) for technology review serve to continually re

- evaluate MACT and thereby ratchet down emissions from each source category under review to control emissions to the greatest degree possible. The commenter pointed out that the court recently ruled again st this view in two court cases and upheld the EPA’s decisions. The commenter contended that the similarity between these rules’ issues and the recently litigated rules are insufficient for that precedent to apply, and additionally argues that, in the comm enter’s opinion, those cases were wrongly decided.

Response: We disagree with the commenter’s view that a MACT standard should be recalculated each time a source category is reviewed for technology review, under CAA section 112(d)(6). In response to a simi lar argument that the EPA was obligated to completely recalculate MACT in conducting a technology review, under CAA section 112(d)(6), the D.C. Cir. held “[w]e do not think the words ‘review, and revise as necessary’ can be construed reasonably as imposing any such obligati on.” NRDC v. EPA, 529 F.3d 1077, 1084, (D.C. Cir. 2008) . The D.C. Cir affirmed this holding more recently in Ass'n of Battery Recyclers v. EPA, 716 F.3d 667, 673 (D.C. Cir. 2013) . (Section 112(d)(6) “could not be construed r easonably as imposing an obligation on EPA ‘to completely recalculate the maximum achievable control technology’ when it revises standards under that provision.”) (Internal citations omitted). Thus, we disagree with the commenter that recent court decision s in Association of Battery Recyclers v. EPA and NRDC v. EPA are sufficiently dissimilar to these decisions as to render them not applicable, and maintain that the issues are the same.

It is, however, appropriate for the EPA to consider data showing chan ges in emissions profiles and emission levels when conducting a technology review under 112(d)(6). This section broadly directs the EPA to review existing standards to determine if revisions are appropriate considering, among other things, developments tha t have occurred since promulgation of the original MACT standard. As previously explained, th e D.C. Circuit has also held that the EPA may permissibly amend improper MACT determinations, including amendments to improperly promulgated floor determinations, using its authority under CAA sections 112(d)(2) and (3). Medical Waste Institute v. EPA , 645 F. 3d 420, 425

- 27 (D.C. Cir. 2011). In doing so, the EPA is not constrained by post

- MACT compliance data. Medical Waste Incinerator

, 645 F. 3d at 426 (resetting MACT floor, based on post

- compliance data, is permissible when originally

established floor was improperly established, and permissibility of the EPA’s action does not turn on whether the prior standard was remanded or vacated). Similarly, the D.C. Circuit ’s December 9, 2011 decision in Portland Cement Ass’n v. EPA , 665 F.3d 177, 189 (D.C. Cir. 2011) confirms that CAA section 112(d)(6) does not constrain the EPA and it may reassess its standards more often, including revising existing floors if need be.

108. Co mment: One commenter (1042

- 0120) stated that a thorough and complete analysis of the EPA’s calculation method is not possible since the EPA’s preamble discussion and MACT floor memorandum lack any details on the analysis itself. The commenter stated that
t he EPA has not provided enough information in the record to support its proposed floor analysis and proposed standards for HCl, HF, and PM. For example, to determine UPL, the commenter explained that the EPA should do statistical analysis related to the no rmality of the test data and possibly transform the data to produce a suitable distribution. The commenter noted that the

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MACT floor memorandum talks about this but does not fully explain how the analysis was done for the fiber glass industry. The commente r asserted that the EPA has a legal obligation under the CAA to include in the record a “statement of basis and purpose” that should include such information. According to the commenter, its absence violates Section 307, and, if not corrected prior to prom ulgation, would render the final rule arbitrary.

Response: As discussed in the preamble to the 2013 proposal and as noted in response to comment number 101 , the PM limit is no longer based on a MACT floor calculation as proposed in 2011. Also, as discussed in the preamble to the 2013 proposal and as noted in the EPA’s response to comment number s 11 7 and 118 , the HF and HCl standards are no longer numerical limits as proposed in 2011, but are being finalized as work practices.

W ith regard to HF and HCl , we proposed work practice standards in our 2013 proposal to reflect comments and our evaluation of test data from industry on our 2011 proposal. We explained that we had re

- evaluated available test data that we had used to calculate the MACT floor limits for the HCl and HF limits proposed in 2011 , and found that most of the test data reflected values that were below the detection limit of the test methods. Specifically, over 80 percent of the test results were values indicating that either HF or HCl, or b oth pollutants in the exhaust gas stream were below the detection limit of the methods. We believe that such values are not a measurement of pollutants but rather an indication that such pollutants are not present in measurable concentrations. (78 FR 22387 ). We therefore proposed work practices standards for the control of HF and HCl emissions from furnaces that would require air pollution control equipment associated with glass

- melting furnaces to be operated according to the parameters established in the most recent performance test. The final rule contains work practices consistent with our 2013 proposal

.

109. Comment: One commenter (1042

- 0299) stated that the 2013 proposal included weaker PM and chromium limits for the wool fiberglass source category than pro posed in 2011, and the commenter requested that the EPA revert to the PM limits proposed in November 2011.

Response: A s a practical matter, the chromium emission limits are unchanged between the 2011 proposal and the 2013 supplemental proposal . The value o f the chromium limit is identical in both the 2011 and 2013 proposals, but we did propose to change the applicability of the chromium limits to only gas

- fired furnaces, and not to electric furnaces. However, that proposed change does not significantly affe ct the stringency of the rule because all the electric furnaces either did not detect chromium emissions during testing, or detected chromium at least one order of magnitude below the proposed limit. Therefore, the change in applicability will not result i n any chromium emissions increases. So

, as a practical matter

, stringency is unchanged. In addition, due to design and construction differences, and as supported by the source test data collected for the rulemaking, electric furnaces do not have the potent ial to emit increasing chromium emission over time, so we do not believe that a limit is necessary to provide assurance against future emissions increases

Regarding the numerical limits for PM for wool fiberglass manufacturing furnaces than had been propos ed in 2011

, the EPA intended for the stringency of the limit to be unchanged. As explained in the 2013 supplemental proposal preamble (78 FR 22387) and our response to comment number 101 , the changes in the numerical limit occurred because the EPA was

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correcting an error in the 2011 proposal. In the 2011 proposal, the EPA intended to set a PM limit that represented what we considered to be the demonstrated current performance of PM controls for the entire population of furnaces as part of the technology review performed under the authority of CAA section 112(d)(6). So

, even though the numerical limit increased, the stringency of the limit the EPA intended to set did not change. We believe that new furnace designs and improvements in control device operat ion, design

, and bag house s are the factors that are responsible for the improvements in PM control performance from 0.5 lb/ton (1999 MACT) to 0.33 lb/ton in the industry. The results of our technology review, including our calculations can be found in the memorandum, “Section 112(d)(6) Technology Review for Wool Fiberglass NESHAP”, which is in t he docket for this rulemaking

.

3. Testing and M onitoring Issues
110. Comment : Two commenters (1042

- 0300/1042

- 0348; 1042

- 0120) requested that the EPA leave the testing durati on of 1 hour for Method 318 unchanged from the MACT compliance requirements originally proposed in 2011 . One commenter (1042

- 0300/1042

- 0348) pointed out that sources were required to test under Method 318 for a period of 1 hour, but the EPA is proposing to change this duration by requiring 10 spectra.

Response : In Method 318, sample gas is continuously extracted from the source and the sample gas is conveyed to a Fourier transform infrared (FTIR) spectroscopy cell where a spectrum of the sample gas is rec orded. Section 8.6.3 of Method 318 specifies that the sample integration time, the sample flow rate through the FTIR gas cell, and the total run time must be chosen so that the collected data consist of at least 10 spectra with each spectrum being of a
sep arate cell volume of flue gas. The EPA is finalizing its proposed change to require 10 spectra for Method 318 rather than specifying a minimum sampling duration to be consistent with the sampling requirements of Method 318.

111. Comment : One commenter (1042

- 0 300/1042

- 0348) expressed concern about proposed changes to Method 316 that would increase the testing duration from 1 to 2 hours. The commenter noted that the increase in sampling time would not increase the accuracy or reliability of the method. The comme nter asked that the EPA retain the original test duration of 1 hour.

Response : We are finalizing, as proposed, the requirement to collect a minimum sampling volume of 2 d ry standard cubic meters (d scm ) ; however, we are not finalizing the proposed minimum sampling run time for EPA Method 316 of 2 hours. Method 316 is capable of formaldehyde detection limits as low as 0.01 ppmv with a 1

- hour test run when matrix interferences are not present. However, where concentrations of formaldehyde may be very low, it may be necessary to collect additional sample volume to ensure that the in

- stack detection capability of the test method is sufficient to demonstrate compliance with the limit in the rule. Although Method 316 is very sensitive, it is incumbent upon the sou rce and tester to ensure that sample collection during performance testing is sufficient for compliance demonstration. To that end, we are finalizing the requirement to collecting 2 dscm sample volume when using Method 316.

112. Comment : One commenter (1042

- 01 20) cautioned the EPA against setting the MACT floor based on data from one test method or testing duration and mandating compliance testing based on data from a different test method or testing duration. The commenter provided

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one example in the proposed rule that the EPA set the MACT floor using Method 316 data for formaldehyde, but now proposes use of Method 318 for compliance testing even though no data were collected using Method 318. Given the very low proposed limits, the commenter was concerned that compliance testing would not correspond with the data used to set the floor and, therefore, a disparity in test methods would cause compliance issues. The commenter provided a second example that the EPA set the MACT floors based on data collected using M ethod 316 during extended four

- hour runs; whereas compliance is based on data collected using fewer runs. The commenter believed it would be more appropriate for economic reasons to perform compliance testing using the shorter runs

– one to two hours, but that it is quite possible that one or two hour runs could result in data that are below the method detection limit (MDL), which when converted to a lb/ton number could exceed the MACT standard. The commenter was concerned with how the EPA would handle non

- detects in such instances and urged the EPA to consider this correlation before publishing its final rule.

The c ommenter urged the EPA to examine the correlation between the test methods the EPA used for calculating the MACT floor for PM, HF, HCl, formaldehyde, phenol, and methanol and proposed test methods for future compliance testing to ensure that these test methods correlate with currently used test methods. The commenter urged the EPA to recalculate the MACT floor so that the same test methods are used when setting the MACT floor and for compliance testing.

For measuring the concentration of formaldehyde, phenol, and methanol, the commenter stated that the use of Method 318 can result in non

- quantifiable levels that are inappropriate to determi ne the levels proposed for this regulation. In the alternative, the commenter requested the option to determine all organics by FTIR Method 318 or determine formaldehyde by Method 316, determine phenol by Method 8270D, and determine methanol by Method 308.

Response: The EPA agrees that Method 316 is capable of obtaining measurements with enough sensitivity to demonstrate compliance for this source category . In response to this comment, we proposed in the April 15, 2013 supplemental notice (78 FR 22387

- 88) that owners or operators could use Method 318 for measuring concentrations of phenol, methanol, and formaldehyde ; Method 316 or Method 318 for measuring concentrations of formaldehyde ; and Method 318 or Method 308 for measuring concentrations of methanol. The final rule, consistent with the 2014 proposal, provides alternative test methods to facilities for demonstrating compliance with the emission limits. For measuring formaldehyde concentrations, the final rule continues to allow owners or oper ators to use EPA Methods 316 or 318. For methanol, facilities can use EPA Method 318 or 308. With regard to the commenter’s suggestion to allow owners or operators to measure phenol concentrations using Method SW

- 846 8270D, we will consider providing this alternative when we evaluate MACT limits for RS lines at wool fiberglass manufacturing facilities as discussed in section V.H of the preamble to the final rule.

R egarding the comment that the same sampling time should be used for both the test data used to establish a MACT limit and the test method used to enforce that limit, for many test methods the detection limit decreases with increases in sampling time (i.e., larger sample volume). As the sensitivity of the method increases, the detection level decrea ses. ICR guidance directs testers and laboratories to gather large r sample volume s (longer test runs) in the pursuit of returning detectable amounts of each analyte. The EPA has adopted a method to establish floor

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limits based on actual emissions measureme nts or, in the case of detection limit issues, a 3x RDL (Representative Detection Limit

- determined from the pool of lab information provided through the ICR) value. The result of this process is that, if the emission limit is not based on actual measured concentrations as applied with the UPL procedure, compliance may be demonstrated with a test that includes detectable amounts of the pollutant of interest , or the data are returned as below the detection limit

. We expect that many emissions measurements w ill be sufficiently above the detection limit such that a UPL

- calculated floor value results in test durations less than the four hour tests required by the ICR; however, we also expect sources, testers, and laboratories to research method detection and ca refully plan their detection limits prior to any compliance sampling and design their testing and analytical protocols to attain detection of the analytes of concern before starting any field work. In no instance should a non

- detect value result in a non

- c ompliance situation unless the tester and/or laboratory does not appropriately consider the concern of detection limitations prior to sampling.

113. Comment: One commenter (1042

- 0120) supported the EPA’s proposed electronic notification, recordkeeping, and repo rting requirements in the 2011 proposal (76 FR 72770, November 25, 2011). The commenter, however, expressed concerns regarding the recordkeeping and notification requirements for refractory brick composition of glass

- melting furnaces. According to the comm enter, because refractory brick composition does not have any effect on hexavalent chromium emissions, the data requested would be irrelevant and therefore, inappropriate for recordkeeping purposes. The commenter believed that, moreover, sources consider t his information as CBI , while some sources have also indicated that such data would be unavailable at certain facilities or plants. The commenter noted that the proposed requirement would subject sources to electronic reporting after January 1, 2012 and wi thin 60 days of completion of each performance testing . The commenter suggest ed the reporting should begin within 60 days of the effective date of the rule instead.

Response: The requirement to report refractory brick composition was initially considered as a way to track the potential for chromium emission increases. Because we are establishing chromium emissions limits in this final rule, there is no longer a need for this information and the final rule amendments do not contain any refractory compositio n recordkeeping and notification requirements. With regard to the commenter’s suggestion to require electronic reporting within 60 days of the effective date of the rule instead of the proposed requirement for electronic reporting within 60 days of complet ion of each performance testing after January 1, 2012, we note that it was not our intent that sources would have to retroactively go back and report all emission tests that were performed since January 1, 2012. Therefore, we have changed the language in t he final rule to simply require reporting within 60 days of each performance test and deleted the reference to January 1, 2012

. Regarding the timing of reporting, we disagree with the commenter that electronic reporting of the results of compliance tests should be delayed until 60 days after the effective date of the f inal r ule. First, the commenters’ preference would amount to submission of only one report while we have information that hexavalent chromium emissions are expected to increase over the life of a wool fiberglass furnace , as further discussed in section VI.B.3 of the preamble to the final rule . This alone illustrates the usefulness of timely data from industry indicating the levels of chromium compounds being emitted from any wool fiberglass furnace. More important is the likelihood that certain wool fiberglass furnaces emitting close to but below the rule limits

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one year may exceed the limits the next year. Second, the public has a right to be aware of the toxic compounds emitted into the atm osphere by wool fiberglass manufacturing facilities and these reporting requirements assure that timely reports are made available to the public as they become available.

Third, we do not believe this requirement is burdensome because test results can now be submitted electronically, as compared to when emissions reports were only available on paper. Moreover, we also believe that this rule, including the reporting requirements, is cost effective because the costs analyses shows the entire cost of the rule (of which reporting requirements are a small fraction) as less than one

- tenth of one percent of the industry profits.

114. Comment : One commenter (1042

- 0299) requested in response to the EPA’s 2013 proposal (78 FR 22370, April 15, 2013) that the EPA require con tinuous monitoring of PM and HCl, as it has done for other source categories, or at the very least, annual testing.

Response : In the final regulation, we are requiring that owners or operators conduct annual emissions tests for chromium. The EPA is finaliz ing the requirements to conduct emissions tests for filterable PM initially and every five years, and to conduct continuous parametric monitoring of control devices used to reduce PM emissions from furnaces, as proposed. As discussed in the 2011 proposal ( 76 FR 72803), the data submitted to the EPA show that most , if not all, facilities are achieving much lower levels of PM emissions than the level allowed under the 1999 NESHAP , and this is also the case for the revised PM emission limit of 0.33 pounds per ton glass in the final rule. We believe that the PM data collected as part of this rulemaking indicate that facilities are maintaining PM emission levels well below the emission limits by using the current parameter monitoring requirements in the rule. The refore, we disagree with the commenter that CEMS and/or annual testing are necessary to ensure compliance with the final PM emission limits.

For HCl, the final rule requires facilities to comply with the work practice standards and the final rule does not require emissions testing for HCl. As discussed in the 2013 proposal (78 FR 22387), the test data submitted to EPA showed that HCl concentration levels were very low (approximately 80 percent of the test data were BDL). Therefore, we did not establish num erical emission limits for HCl. Based on the low levels of HCl emissions, we disagree with the commenter that additional requirements beyond the work practice standards in the final rule are justified for HCl emissions.

B. Issues Related to Major Sources Only

1. Applicability
115. Comment : One commenter (1042

- 0300/1042

- 0348) objected to footnote 3 in the 2013 proposal (78 FR 22374, April 15, 2013) explaining that the EPA’s original intent was to regulate all wool fiberglass furnaces, and the commenter expressed the op inion that the EPA and industry had agreed prior to promulgation of the MACT rule that certain furnaces should be exempt from regulation. The commenter referred to the 2002 EPA Applicability Determination in which the EPA agreed that furnaces feeding a lin e that is not processing formaldehyde were not subject to the MACT standard. Therefore, the commenter found the footnote to be misleading on this matter. The commenter (1042

- 0348) also requested the exact citation for the

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EPA’s reference to EPA’s response indicating EPA’s original intent regarding applicability to

non

- bonded lines.

Response : The EPA’s footnote 3 in the 2013 proposal (78 FR 22374, April 15, 2013) was intended to clarify the EPA’s original intent in 1999 regarding the applicability of MACT to

non

- bonded lines, and simply reiterated the EPA’s intent stated in the RTC to the original 1999 rulemaking. As documented in section 2.3 of the RTC accompanying the 1999 promulgation preamble (“Summary of Public Comment and Responses on Wool Fiberglass Ma nufacturing NESHAP,” March 31, 1999, available in EPA

- HQ

- OAR

- 2010

- 1042

- 0244), in response to a comment requesting that the EPA modify the definition of “wool fiberglass” by adding “bonded” to the definition, we responded that “Because the EPA’s intent is t o regulate all glass furnaces located at wool fiberglass plants that are major sources of HAP, and not just those melters that feed molten glass to manufacturing lines producing bonded wool fiberglass products, the EPA has decided to not modify the definit ion of “wool fiberglass” by adding “bonded” to the definition.”

We disagree that this clarification of the EPA’s original 1999 intent creates confusion about the EPA’s current intent. The EPA made it clear in the 2011 and 2013 proposals that the major sour ce rule applies to non

- bonded lines (regardless of the EPA’s original intent), and that the area source rule would apply to bonded lines.

2. Technology Developments and C ontrols
116. Comment : One commenter (1042

- 0121) stated that the EPA had appropriately recogni zed in their 2011 proposal (76 FR 72770, November 25, 2011) that there are significant industry developments that require the EPA to update the PM and formaldehyde standards for the Wool Fiberglass Manufacturing source category. The commenter expressed sup port for the EPA’s proposed PM and formaldehyde standards and the proposal to set a chromium limit under CAA section 112(d)(6). The commenter urged EPA to ensure that these limits are as stringent as allowed under the statute. The commenter also expressed support for EPA’s decision to seek and obtain appropriate test data to support these proposed standards.

Response: The EPA acknowledges this comment. Regarding the proposed formaldehyde, methanol, and phenol limits for RS lines, as noted in section V.H of the preamble to the final rule, we are not establishing MACT standards for RS manufacturing lines at wool fiberglass manufacturing facilities in this final action. We have issued an ICR under CAA section 114 to collect updated emissions and process informa tion from the industry and we will analyze the ICR data and evaluate MACT limits for RS lines at wool fiberglass manufacturing facilities at a future date.

3. HC l and HF Emission Limits for Glass

- Melting Furnaces
117. Comment: One commenter (1041

- 0081) supported the EPA’s decision to set limits for previously uncontrolled emissions of HF and HCl from glass

- melting furnaces. The commenter noted that CAA section 112(d) requires the EPA to set emission standards for all emitted po llutants. According to the commenter, closing loopholes and correcting problems that exist in the existing standard is an important part of the EPA’s job under CAA section 112(d)(6). The commenter believed that EPA should ensure that these standards fully satisfy both CAA sections 112(d)(2) and 112(d)(3).

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Response: As explained above, the EPA disagrees that correcting problems with existing MACT standards is a necessary part of a 112(d)(6) technology review conducted under CAA section 112(d)(6) . Nonethele ss, EPA is finalizing new standards under 112(d)(2) for HCl and HF as part of this final action. It is not, however, promulgating these standards as part of its 112(d)(6) technology review. For the reasons discussed in the preamble to the 2013 proposal (78 FR 22387) and explained in response to comment 118, the EPA is finalizing work practice standards for HCl and HF. Further, the EPA is revising these work practice standards to address public comments received in response to the 2013 and 2014 proposals . Sp ecifically, we are replacing the 2013 proposed requirement that cullet be “free of chloride

- , fluoride

- , and fluorine

bearing constituents” with work practice standards that require wool fiberglass facilities to maintain records from either cullet supplier s or their internal inspections showing that cullet is free of the following components that would form HF or HCl in the furnace exhaust (i.e., chlorides, fluorides and fluorine): glass from industrial (also known as continuous strand, or textile) fibergla ss, cathode ray tubes (CRT), computer monitors that include CRT, and glass from microwave ovens, televisions or other electronics. For further discussion of this revision, refer to section V I .D of the preamble to the final rule.

118. Comment : One commenter (104 2

- 0120) contended that HCl and HF emissions from the wool fiberglass industry are both so low and present such low risk that regulation is not necessary. The commenter argued that, despite the EPA’s claim in the preamble to the 2011 proposal that the Brick MACT case requires regulation of every HAP emitted (regardl ess of amount), the EPA has not followed that argument in other recent rulemakings. In the recent Utility MACT, the commenter noted that the EPA did not regulate, either directly or by surrogate, any organic HAP from coal

- fired utilities. The commenter stated that this is despite the EPA’s own AP

- 42 factors that indicate significant emission factors for a number of organic HAP. The commenter recommended that the EPA take the same approach for the w ool fiber glass source category because the several below

- MDL results in the test data indicate that the numeric standard is close enough to the detection and quantification limits that companies could not reliably show compliance.

According to the comment er, the EPA can revise an existing MACT standard only under CAA section 112(d)(6). The commenter cited that the NRDC v. EPA decision (Hazardous Organic NESHAP RTR Rule) plainly holds that EPA is not required to correct prior MACT standards or recalculate M ACT standards under CAA section 112(d)(6). Therefore, the EPA does not need to regulate HCl and HF, but, if it decides to do so, the EPA does not need to set the standard under CAA sections 112(d)(2) and (3).

The commenter stated that the EPA’s interpretation is incorrect and that the a gency is not mandated to regulate de minimis HAP like HCl and HF, as demonstrated by the EPA’s decision not to regulate organic HAP in the recent Utility MACT. Moreover, the comm enter contended that the amount of HCl and HF emitted by any single wool fiber glass facility does not meet the 10 tpy and 25 tpy threshold required to trigger MACT applicability.

Response: The EPA is finalizing new standards under 112(d)(2) for HCl and HF as part of this final action. It is not, however, promulgating these standards as part of its 112(d)(6) technology review. For the reasons discussed in the preamble to the 2013 proposal (78 FR 22387) the EPA is finalizing work practice standards for HCl a nd HF. Further, the EPA is

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revising these work practice standards to address public comments received in response to the 2013 and 2014 proposals. As explained in the preamble to the 2013 proposal (78 FR 22387), in response to this comment on the HCl and HF emission limits proposed in 2011, we re

- evaluated test data that we used to calculate the MACT floor for the proposed HCl and HF standards, and we had found that most of the test data reflected values below the detection limit of the test method. Specific ally, over 80 percent of the test results were values indicating that either HF or HCl, or both pollutants in the exhaust gas stream, were below the detection limit of the methods. We believe such values are not a measurement of pollutants but rather an in dication that such pollutants are not present in measurable concentrations. We therefore proposed in 2013 work practices standards for the control of HF and HCl emissions to ensure that the cullet does not include waste materials that would form HF or HCl in the furnace exhaust. In the final rule, we are revising the work practice standards proposed in 2013 and 2014, as discussed in section VI.D of the preamble to the final rule.

As explained above, the EPA disagrees that correcting problems with existing M ACT standards is a necessary part of a 112(d)(6) technology review. We also disagree with the comment that CAA section 112(d)(6) is the EPA’s sole authority for revising existing MACT standards. As a general matter, an agency remains free to revise imprope rly promulgated or otherwise unsupportable rules, even in the absence of a remand from a Court. United Gas Improvement Co. v. Callery Props. Inc.

, 382 U.S. 223, 229 (1996) (An agency, like a court, can undo what is wrongfully done by virtues of its order.” ). As explained in earlier responses in this response to comment document, we believe that CAA section 112 does not expressly address this issue, and the EPA has discretion in determining how to address improperly promulgated floor determinations. CAA sect ion 112(d)(6) provides that the agency must review and revise “as necessary.” The “as necessary” language must be read in the context of the provision, which focuses on the review of developments that have occurred since the time of the original promulgati on of the MACT standard and thus, should not be read as a mandate to correct flaws that existed at the time of the original promulgation. Further, we believe that Portland Cement Ass’n v. EPA , 665 F.3d 177, 189 (D.C. Cir. 2011) confirms that EPA is not con strained by CAA section 112(d)(6) and may reassess its standards more often, including revising existing floors if need be. We also note that the D.C. Circuit also held that EPA may permissibly amend improper MACT determinations, including amendments to im properly promulgated floor determinations, using its a uthority under CAA sections 112 (d) (2) and (3). Id

. Thus, we believe that we may amend improper MACT determinations, including amendments to improperly promulgated floor de terminations, under sections 1 12 (d) (2) and (3). Medical Waste Institute v. EPA

, 645 F.3d 420, 425

- 27 (D.C. Cir. 2011) (resetting MACT floor, based on post

- compliance data, permissible when originally

- established floor was improperly established, and permissibility of the EPA’s action does not turn on whether the prior standard was remanded or vacated). The commenter is, thus, incorrect that CAA section 112 (d)(6) provides the exclusive authority to address for e.g., HCl and HF emissions here. Put another way, if the EPA did not adopt a proper MACT standard initially, it is not amending a MACT standard but adopting one for the first time. Here, the EPA adopted no MACT standard at all for these HAP, an approach soundly rejected by the D.C. Circuit in National Lime , 233 F.3d at 633

- 34. We a lso note that we note that i n National Lime Association v. EPA , 233 F.3d 625 (D.C. Cir. 2000), the D.C. Circuit remanded the Portland Cement MACT to EPA to establish MACT floors for HCl holding that we had a clear “statutory obligation to set emission stan dards for each listed HAP.” Therefore, we believe the EPA is not barred from making MACT floor determinations and issuing MACT standards pursuant to CAA

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sections 112(d)(2) and (3) for this source category. Additionally, in several recent rulemakings, we ha ve chosen to fix underlying defects in existing MACT standards under CAA sections 112(d)(2) and (3), the provisions that directly govern the initial promulgation of MACT standards (see National Emission Standards for Hazardous Air Pollutants From Petroleum Refineries, October 28, 2009, 74 FR 55670; and National Emission Standards for Hazardous Air Pollutants: Group I Polymers and Resins; Marine Tank Vessel Loading Operations; Pharmaceuticals Production; and the Printing and Publishing Industry, April 21, 20 11, 76 FR 22566). We believe that our approach is reasonable because using those provisions ensures that the process and considerations are those associated with initially establishing a MACT standard, and it is reasonable to make corrections following the process that would have been followed if we had not made an error at the time of the original promulgation.

We also disagree with the comment that the EPA is not mandated to regulate de minimis HAP like HCl and HF. While the EPA’s de minimis authority exi sts to help avoid what might be perceived as excessive regulation of tiny amounts of pollutants, it is unavailable “where the regulatory function does provide benefits, in the sense of furthering the regulatory objectives, but the agency concludes that the acknowledged benefits are exceeded by the costs.” Alabama Power v. EPA , 636 F.2d 323, 360

- 61 &n.89 (D.C. Cir. 1979). According a de minimis exemption
to CAA section s 112(d)(2) and (3) are unavailable because it would frustrate a primary legislative goal b y carving out tons of HAP emissions from regulation. Moreover, the EPA’s rejection of the de minimis concept has been affirmed by the U.S. Court of Appeals for the D.C. Circuit in National Lime Ass’n v. EPA , 233 F.3d 625, 640 (D.C. Cir. 2000), where the co urt rejected the petitioner’s claim that in light of both high costs and low quantities of HAP at issue in that rule, the EPA should read a de minimis exemption into the requirement to regulate all HAP emitted by major sources. The Court found that “EPA r easonably rejected this argument on the ground that the statute ‘does not provide for exception from emissions standards based on de minimis principles where a MACT floor exists.’ ” National Lime Ass’n , at 640. We also continue to believe that CAA section 112 is replete with careful definitions of volume or effect based limitations on regulation, indicating that Congress has already defined what amounts of HAP emissions are too small to warrant MACT standards. The requirement to adopt MACT emission limitat ions, for example, applies without exception to “category or subcategory of major sources . . . of [HAP].” CAA section 112(d)(1). For sources below the major sources threshold, however, EPA has discretion to require “generally available control technologie s or management practices.” CAA section 112(d)(5). Congress has thus defined volumetrically which sources’ emissions are small enough not to warrant mandatory MACT standards.

Finally

, we also disagree with the comment that the EPA did not “did not regulat e, either directly or by surrogate, any organic HAP from coal

- fired utilities,” in the recent Utility MACT rule. To the contrary, the EPA did set work practice standards for organic HAP, under CAA section 112(h). Additionally, in the Boilers NESHAP we set MACT standard for HCl. As explained earlier above, both HCl and HF are listed HAP, under CAA section 112(b) and we are required to establish MACT standards for all HAP emitted by major sources, un der CAA sections 112(d)(2) and (3).

119. Comment: One commenter (1042

- 0120) urged the EPA to establish risk

- based standards for HCl and HF emissions from the wool fiberglass industry . The commenter stated that CAA section 112(d)(4) expressly authorizes the EPA to establish risk

- based standards for

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threshold pollutants for which a health threshold has been established. 42 U.S.C. § 7412(d)(4)

. The commenter asserted that this provision was established by Congress because “[f]or some pollutants a MACT emissions li mitation may be far more stringent than is necessary to protect public health and the environment” and quotes from the legislative history for the 1990 CAA amendments

. The commenter also asserted that the EPA has previously determined that HCl is a thresho ld pollutant and that the EPA has established what the commenter characterized as a lack of risk. The commenter further asserted that health

- based limits would be more reasonable and achievable and would enable the EPA to achieve the ample margin of safety to health and the environment

. Response: Section 112(d)(4) of the CAA provides that: “[w]ith respect to pollutants for which a health threshold has been established, the Administrator may consider such threshold level, with an ample margin of safety, whe n establishing emissions standards under this subsection.” Notably, the statute confers limited discretionary authority on the EPA and does not mandate the use of health

- based standards. The legislative history cited by the commenters contains similarly pe rmissive language and does not suggest that health

- based standards would be required in any circumstances. Specifically, the legislative history quoted by the commenter provides that “where health thresholds are well

- established . . . and the pollutant pre sents no risk of other adverse health effects, including cancer, for which no threshold can be established, the administrator may use the threshold with an ample margin of safety (and not considering cost) to set emissions limitations for sources in the ca tegory or subcategory.” S. Rep. No. 101

- 228, at 144 (1989). In other words, where certain preconditions are met (i.e., health thresholds are well

established and the pollutant presents no other risks), the EPA has discretionary authority to set health

- base d standards. Here, the commenter urges the EPA to create risk

- based limits based largely on their assertion that the EPA has authority to do so because the pre

- conditions are met. The commenter does not, however, offer a rationale to support their assertio n that the EPA should exercise this discretionary authority in this rulemaking. In fact, the only rationale offered is a bald assertion that such limits would be more reasonable and achievable and would enable the EPA to achieve the ample margin of safety to health and the environment. This comment was offered in response to the 2011 proposal in which EPA had proposed to establish numeric emissions limits for HCl and HF for furnaces at wool fiberglass manufacturing facilities. In this final rule case we are setting work practice standards for HCL and HF because the emissions of HCl and HF are so low as to make measurement impracticable. As explained in the 2013 proposal (78 FR 22389), these standards are not only reasonable and achievable, but will in fact h ave minimal if any impact on the wool fiberglass industry

.

120. Comment: One commenter (1042

- 0120) asserted that the EPA’s position that “synthetic area sources” may be considered in the floor determination for HCl and HF is unfounded because CAA section 112 e xpressly defines the terms “major source” and “area source” and provides for separate listing and regulation of major sources and area sources, but that the statute does not distinguish between “area sources” and “synthetic area sources.” Therefore, the co mmenter contended that “synthetic area sources” are not part of a corresponding major source category and cannot be used in determining the MACT floors for the major source category. The commenter argued that the MACT floor should be recalculated using dat a from only sources that are currently subject to the MACT.

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Response: We disagree with the comment that our use of synthetic area sources in MACT floor calculations is unfounded. We believe that the better interpretation of the plain language of CAA secti on 112(d)(3) and relevant legislative history requires that synthetic minor sources should be included in MACT floor determinations. As explained in previous rulemakings ( e.g., Brick NESHAP, 68 FR 26697

– 26698, May 16, 2003), the EPA has determined that inc luding synthetic area sources in calculating the MACT floor for major sources is consistent with CAA section 112(d). We continue to believe that inclusion of synthetic area sources in MACT floor determinations is justified for the reasons explained below. Section 112 of the CAA does not specifically address the inclusion of synthetic area sources in the MACT floor calculations. These are sources that emit fewer than 10 tons per year of any HAP or fewer than 25 tons per year of any combination of HAP because they use some emission control device(s), pollution prevention techniques or other measures (collectively referred to as controls in this preamble) adopted under Federal or State regulations. If not for the enforceable controls they have implemented, synt hetic area sources would be major sources under CAA section 112 of the CAA. We believe that the better interpretation of the CAA's plain language and legislative history requires that synthetic area sources be included in the MACT floor determinations.

Fi rst, the plain language of the statute makes clear that our MACT floor determinations are to reflect the best sources in a category. For new sources in a category or subcategory, the MACT floor shall not be less stringent than the emission control that is achieved in practice by the best

- controlled similar source, as determined by the EPA. Section 112(d)(3) of the CAA requires that MACT floors reflect what the best controlled new sources and the best performing existing sources achieve in practice. These ph rases contain no exemptions and are not limited by references to sources with or without controls. Therefore, they suggest that all of the best

controlled or best

- performing sources should be considered in MACT floor determinations, regardless of whether o r not such sources rely upon controls.

Second, CAA section 112(d)(3) expressly excludes certain sources that meet LAER requirements from MACT floor determinations for existing sources. (See CAA section 112(d)(3)(A).) The fact that Congress expressly exclud ed such LAER sources but did not also exclude synthetic area sources suggests that no exclusion was intended for synthetic area sources. Indeed, nothing in the statute suggests that the EPA should exclude a control technology from its consideration of the MACT floor because the technology is so effective that it reduces source emissions such that the source is no longer a major source of HAP.

Third, the EPA disagrees that the CAA contemplates that synthetic area sources must be treated like true area sourc es and excluded from MACT floor determinations. Section 112(a) of the CAA defines a major source as: any stationary source or group of stationary sources located within a contiguous area and under common control that emits or has the potential to emit

cons idering controls, in the aggregate, 10 tons per year or more of any hazardous air pollutant or 25 tons per year or more of any combination of hazardous air pollutants * * * (See CAA section 112(a)(1).) An area source is defined as any stationary source of hazardous air pollutants that is not a major source. (See CAA section 112(a)(1).) In the major source definition, the reference to a source's potential to emit considering contro ls allows the interpretation that a source's potential to emit before and after controls is relevant, such that synthetic area sources may be considered within the meaning of this definition and included in MACT floor determinations for categories of major sources. This is because w e believe synthetic area sources, because they have already

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reduced HAP emissions below the major source threshold, they are among the best performing 12 percent of existing sources and thus help to define the level of the MACT e mission limit. Thus, i ncluding synthetic area sources in MACT floor determinations ensures that MACT floors reflect the best

- performing sources, as the CAA requires. While the effect of excluding the best performing sources in a category from MACT floor de terminations and therefore would be contrary to the statutory mandate that the EPA set MACT floors based on the levels the best controlled new sources and the best performing existing sources achieve in practice. We believe the statutory reference to poten tial to emit considering controls should be read in a manner consistent with the other requirements of section 112(d) of the CAA to allow for the consideration of synthetic area sources in MACT floor determinations for categories of major

sources.
Fourth, relevant legislative history for this section suggests that synthetic area sources should be included in MACT floor determinations. In a floor statement, Senator Durenberger stated that in implementing section 112(d)(3) of the CAA, "the [Senate] managers intend the Administrator to take whatever steps are necessary to assure that [the Administrator] has collected data on all of the better

- performing sources within each category. [The Administrator] must have a data

- gathering program sufficient to assure th at [EPA] does not miss any sources that have superior levels of emission control." (See Environment and Natural Resources Policy Division, Congressional Research Service, 103d Cong., S. Prt. 103

- 38 (prepared for the U.S. Senate Committee on Environment and Public Works), A Legislative History of the Clean Air Act Amendments of 1990 at 870, Nov. 1993, emphasis added.) This statement underscores that Congress intended for MACT floor determinations to reflect consideration of all of the sources in each categor y with the best emission controls. We believe it would be inconsistent with Congress's intent and the plain language of the CAA to exclude synthetic area sources

- those sources with superior controls which became synthetic area sources by implementing such controls

- from MACT floor determinations. Therefore, we believe that the inclusion of synthetic

area sources in MACT floor determinations is justified because of the reasons explained above.

The EPA Title V Operating Permits Program (Title V) tracks the p erformance, compliance, operational status and major source status of all permitted sources, including wool fiberglass facilities currently in operation in the U.S. In finalizing this rule, we have not included sources that have been identified by the Titl e V program as area sources in the floor calculations. Therefore, true area sources (i.e., sources that do not have the potential to emit at least 10 tons per year of a single pollutant or at least 25 tons per year of any combination of HAP) were not part of the MACT floor calculation for phenol, formaldehyde, or methanol.

As also explained in the November 2011 proposal, the commenter conducted a voluntary survey among all owners and operators of mineral wool production and wool fiberglass manufacturing fa cilities. The survey sought test data for PM, and HAP emissions, such as hydrogen fluoride and hydrochloric acid and information on process equipment, control devices, point and fugitive emissions, and practices used to control point and fugitive emissions . Further, the EPA requested and industry agreed in a May 5, 2010 letter, that a subset of facilities that were representative of emission sources from wool fiberglass industries would conduct testing and submit existing test data. The May 5, 2010 letter i ndicated that the bases for representativeness included design type and size of process units or equipment, fuel type, operating temperatures, control devices and raw material content. The commenter did not

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identify any sources as synthetic area sources in its May 5, 2010 letter. Rather, the letter states in pertinent part that “new hydrogen fluoride and hydrochloric acid data will be collected from Johns Manville, Richmond, IN facility and Knauf’s Shasta Lake, CA facility.” The letter further stated Owens Corning operates a Cold Top Electric furnace with batch wetting and “new hydrogen fluoride and hydrochloric acid data will be collected from Owens Corning Kansas City, KS facility.” (p. 7)

.

121. Comment: One commenter (1042

- 0120) contended that the HF and HCl d ata from the following sources that the EPA used to set the MACT floor for HCl are below

- MDL, and that the EPA should remove all of these sources from the calculation for the MACT floor for HF and HCl: Owens Corning’s Kansas City, Kansas (K5); Owens Cornin g’s Newark, Ohio (F6); Knauf’s Shasta Lake, California (641); CertainTeed’s Kansas City, Kansas (K2); Guardian’s Mineral Wells, Mississippi; Johns Manville’s Richmond, Indiana (incorrectly split into two sources by EPA); and Johns Manville’s Defiance, Ohio (3 sources).

The commenter argued that below

- MDL data are unquantifiable and that using below

MDL data is likely to set limits so stringent that the best performing sources cannot even meet those limits. The commenter observed that every source relied upo n to set the MACT floor is below

- MDL data; and the majority of HCl data points are below the detection limit. The commenter contended that facilities will have difficulty showing compliance with an emission limit that is based on data from testing that was below

- MDL. According to the commenter, the EPA should only use values that are above the MDL (i.e., actual values) in calculating the MACT floor, and that the emissions floor must be determined by quantifiable data.

According to the commenter, in the Boil er MACT, the EPA reassessed the proposed emission limits for dioxins/furans. The commenter noted that, as explained by the EPA, a large amount of the emission measurement used to set the dioxin/furan limits were below the level that could be accurately mea sured. Alternatively, the commenter stated that the EPA could propose a work practice standard in order for facilities to show compliance. Under the Boiler MACT, the commenter noted that the EPA chose to regulate dioxins/furans by using a work practice
sta ndard. In that case, the commenter stated that 55 percent of facilities tested had dioxin/furan emissions below the MDL for EPA Method 23 test. The commenter stated that a work practice standard would allow facilities to decrease HCl and HF emissions and b e able to show compliance.

Response: We disagree with commenter that we should disregard values less than the MDL in the data set used to calculate the floor. As explained in earlier responses, we evaluated test data that we had used to calculate the MACT floor limits for HCl and HF in response to comments such as this one. Industry had conducted testing in an attempt to obtain data for the acid gases HF and HCl, under the terms of the voluntary survey. Emissions tests were conducted over three 1

- hour test runs, which is, for similar industries, sufficient time to detect these acid gases when they are emitted. However, even with 3

- hour sampling times, such data were not obtained. Rather, we found that most of the test data reflected values that were below th e detection limit of the test method. Specifically, more than half (80 percent) of the test results were values indicating that either HF or HCl in the exhaust gas stream was below the detection limit of the method. As earlier explained also, such values a re not a measurement of the pollutant but indicate that the pollutant was not present in measurable concentrations. We therefore

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proposed work practice standards for HF and HCl in our April 15, 2013 supplemental proposal to reflect comments and our evaluat ion of test data from industry on our November 2011 proposal. As explained in our April 15, 2013 supplemental proposal, EPA regards situations where, as here, the majority of measurements are below the detection limit as being a situation where
measurement is not “technologically practicable” within the meaning of section 112(h)(2)(B). EPA also believes that unreliable measurements raise issues of practicability, feasibility and enforceability. The application of measurement methodology in this situation wo uld also not be “practicable due to . . . economic limitation” within the meaning of section 112(h)(2)(B) because it would just result in cost expended to produce analytically suspect measurements. (78 FR 22387). Section 112(h) of the CAA “allows EPA to s ubstitute work practice standards for emission floors only if measuring emission levels is technologically or economically infeasible.” Sierra Club v. EPA , 479 F. 3d 875, 884 (D.C. Cir. 2007.

Additionally, as explained in the Industrial Boiler NESHAP, th e EPA continues to believe that emissions from a common stack should be considered as representing the average emissions of process units ̧ in this instance a furnace, exhausting to the common stack and thus, should be considered representative of emissions from either process units or furnaces. The commenters have provided no data to support the contention that this assumption is false. The EPA used data from combined stacks only where both furnaces were operating. Similar to testing conducted for the volun tary survey, the EPA expects that companies will comply with the final rule by conducting testing at the common stack as that is usually where the sampling locations are (rather than in the intermediate ductwork) and will report the results as being for ea ch furnace

.

122. Comment : One commenter (1042

- 0348) asked for clarification on whether the limits on cullet apply to the company’s own internal cullet, or only to external cullet purchased from third

- party suppliers.

Response: The final work practice standards apply only to external cullet used at a wool fiberglass manufacturing facility because based on industry representations external cullet is the source of chloride

- , fluoride

- , and fluorine

- bearing constituents at wool fiberglass manufacturing facilities.

123. Comment : One commenter (1042

- 0347) argued that the HCl and HF work practice standards should require reporting, not just recordkeeping, to demonstrate compliance and enable citizen to be informed and participate in enforcement. The commenter stated that t he EPA has not justified excluding these data from reporting.

Response: The final rule specifies recordkeeping requirements for owners or operators to demonstrate compliance with the work practice standards for HCl and HF emissions. We believe that the fin al rule requirements will ensure compliance. As explained in the section VI.D of the preamble to the final rule, we found that most of the test data reflected values that were below the detection limit of the test method. Specifically, approximately 80 per cent of the test results were values indicating that either HF or HCl in the exhaust gas stream was below the detection limit of the method. Given the very low level of HCl and HF emitted from wool fiberglass facilities, we do not believe that requiring ad ditional reporting requirements is warranted.

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4. Formaldehyde, Phenol, and Methanol Limits
124. Comment : One commenter (1042

- 0120/1042

- 0300) stated that the proposed limits for formaldehyde, phenol, and methanol seem superfluous given that majority of the fiberglass industry is no longer subject to the MACT standards since, according to the commenter, only

“ bonded” lines using PF binders are subject to the Wool Fiberglass MACT standard. According to the commenter, 23 facilities have switched to non

- PF binders while most other facilities are in the process of switching to non

- PF binders and would have complete d that process before the new MACT compliance deadline, which means that there has been a virtual elimination of formaldehyde emissions from the binder for the vast majority of the fiber glass building insulation industry.

The commenter also expressed conc erns regarding the EPA’s proposed limits for formaldehyde, phenol, and methanol in that while most of the industry has voluntarily switched from a PF binder to non

- PF binders, certain products continue to use PF binders. Therefore, the commenter contended that it remains important that the limits for formaldehyde, phenol, and methanol be feasibly achieved when PF binder is used, and that some formaldehyde and methanol is created from the combustion of natural gas in the wool fiber glass production
process e ven when PF binders are not used.

Response: Regarding the comment that the proposed limits for formaldehyde, phenol, and methanol “seem superfluous given that majority of the fiberglass industry is no longer subject to the MACT standards,” the EPA disagree s. The final standards are based on test data provided by major sources pursuant to a voluntary survey that they conducted. As explained in the preamble to the final rule, we are establishing emission limits for formaldehyde, phenol and methanol from FA li nes at the MACT floor level of control even though there is an existing standard for formaldehyde in the current MACT rule. This is because in conducting our review, we also found that in the current rule we had calculated a MACT floor for formaldehyde tha t was intended to be achievable by all existing sources. This is an approach that the D.C. Circuit has consistently rejected. “EPA may not deviate from section 7413(d)(3)’s requirement that floors reflect what the best performers actually achieve by claimi ng that floors must be achievable by all sources using MACT technology.” Cement Kiln Recycling Coalition v. EPA , 255 F.3d at 861. (“EPA cannot circumvent Cement Kiln’s holding that section 7412(d)(3) requires floors based on the emission level actually ach ieved by the best performers (those with the lowest emission levels), not the emission level achievable by all sources, simply by redefining “best performing” to mean those sources with emission levels achievable by all sources.” Sierra Club v. EPA , 479 F. 3d at 881. (Emphasis in original). Additionally, the EPA proposed to discontinue the use of formaldehyde as a surrogate for phenol and methanol because we no longer believe that there is a correlation and therefore, reasonable bases, between formaldehyde and phenol and methanol. 76 FR 72788, 72791 : 72796. ( The EPA may attribute characteristics of a subclass of substances to an entire class of substances if doing so is scientifically reasonable. Dithiocarbamate Task Force v. EPA, 98 F.3d 1394, 1399 (D.C. Cir . 1996)). Based on our revised analyses, we are setting standards for FA lines at the MACT floor level of control for these emissions.

We note that sources should have already installed thermal oxidizers to control emissions of formaldehyde in response to the existing MACT rule requirements. Thus, any further reductions called for in the final action may not necessitate the installation of new air pollution controls.

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Regarding RS manufacturing lines at wool fiberglass manufacturing facilities, we are not

e stablishing in this final action standards for formaldehyde, phenol, and methanol. We have issued an ICR under CAA section 114 to collect updated emissions and process information from the industry, and we will analyze the ICR data and evaluate MACT limits for RS lines at wool fiberglass manufacturing facilities at a future date (see section V. H of the preamble to the final rule).

Comment: One commenter (1042

- 0120) asserted that the EPA incorrectly calculated the floor for FA lines because the EPA counted certain sources that share a common stack as one source for the curing section

– Johns Manville line 81 at Defiance, Ohio and lines 92 an d 93 at Cleburne, Texas. According to the commenter, even though there are no MACT limits for FA lines, the state permit imposes a bubble emission limit across the two lines, because Johns Manville cannot distinguish total emissions from each line. Therefo re, the Cleburne, Texas lines should be counted as one line, not two. The commenter also urged the EPA to consider the total emissions from Cleburne, Texas flame attenuation and the total emissions from Defiance, Ohio Line 81 as either one line each, or tw o lines in total. By doing so, the commenter noted that the average (before EPA applied its confidence level analysis) should be what is reflected in the “Two Line” column in the table below. But even if the Cleburne, Texas lines are considered separate, t he calculated average is still incorrect, and counting as three lines, the commenter argued that the average (before EPA applied its confidence level analysis) should be what is reflected in the “Three Line” column in the table below (all numbers in lb/ton ). According to the commenter, these numbers are far higher than the numbers in the EPA’s spreadsheet and way higher than even the proposed standards. The commenter opined that it is reasonable to conclude that the EPA did not properly account for the scie ntific notation in which all stack test data were reported. The commenter stated that, perhaps, the EPA did not include all of the forming and curing stacks, though the footnote in EPA’s spreadsheet indicates that such consideration was intended.

Response: At the November 25, 2011 proposal, the EPA only had emissions test data for FA lines making heavy density products. The 1999 MACT standard for the Wool Fiberglass Manufacturing established two subcategories for the forming process (i.e., FA and RS lines )

. It also included no control floors for existing sources that make light density, automotive and heavy density products on FA line. 34 But
, CAA section 112(d) requires the EPA to set standards for all HAP. Therefore, it was our intent to eliminate the subcat egories for FA lines because we believed that the technical or design differences that distinguished these subcategories in 1999 no longer existed. We, however, did not clearly state that we were eliminating the subcategories for FA lines. In response to c omments such as this one, in our April 15, 2013 supplemental notice, we proposed eliminating the subcategories for FA bonded lines because we believe d that the technical or design differences that distinguished these subcategories when the original rule wa s developed no longer exist. We also proposed establishing standards at the MACT floor level of control for phenol, formaldehyde and methanol emissions from FA bonded lines. As the

34 W e divided the FA lines into 4 subcategories: 1. light density, 2. automotive, 3. heavy density and 4. pipe products. We set standards for two subcategories

-- heavy density (new) and pipe product (new and existing). And we said "[b]ecause no controls are currently used, the MACT floor is no control and be cause the cost effectiveness of additional controls beyond the floor is not reasonable , the Agency is not setting emission limits for existing FA manufacturing lines producing [1] light

- density, [2] automotive or [3] heavy

- density products or new FA manufa cturing lines producing [1] light

- density or [2] automotive products ." 61 Fed. Reg. 15239 (March 31, 1997).

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commenter notes, Johns Manville only submitted data for FA lines producing heavy density products and no data for FA lines producing pipe products. Additionally, we note that industry had indicated that the test data for this subcategory were representative of other subcategories. Thus, the data available to us at proposal were o nly emissions test data for heavy density products. As earlier explained, CAA section 112(d)(3) requires the EPA to promulgate standards that must be at least as stringent as the average emissions limitation achieved by the best performing 12 percent of ex isting sources “for which the Administrator has emissions information.” ( The EPA typically has wide latitude in determining the extent of data

- gathering necessary to solve a problem. NRDC v. EPA , 529 F.3d 1077, 1086) (D.C. Cir. 2008)

. Since both our November 2011 and April 15, 2013 proposals

, no additional information has been provided to support further subcategor ization of FA lines. We are therefore concluding that the limits developed for FA lines are representative of all products made on FA lines and that further subcategorization was no longer supportable.

As also explained in our April 15, 2013 proposal, in examining the 1999 MACT rule, we found that we had set emissions standards for certain subcategories of the FA bonded lines. (78 FR 22387). But

, EPA has a “clear statutory obligation to set emission standards for each listed HAP. Although Sierra permits the agency to look at technological controls to set emissions standards, it does not say that EPA may avoid setting standards for HAP not controlled with technology.” National Lime Association v. EPA , 233 F.3d 625, 634 (D.C. Cir. 2000)(internal citation o mitted). As explained in section VI.C of the preamble to the final rule, we are therefore, also finalizing emissions limits at the MACT level of control for formaldehyde, phenol and methanol for flame attenuation lines.

125. Comment: One commenter (1042

- 012 0) noted that all data used by the EPA to calculate emission limits for formaldehyde, methanol, and phenol for FA lines included only those lines producing heavy density products. The commenter stated that Johns Manville did not submit any data for FA line s producing pipe products, because Johns Manville only uses FA lines as a backup for pipe insulation products. The commenter stated that the EPA’s spreadsheet of the floor locations did not include anything for FA lines making pipe products. Thus, the

comm enter expressed concern that they do not know how the EPA calculated the floor for FA lines making pipe products.

Response: As the commenter notes, Johns Manville only submitted data for FA lines producing heavy density products and no data for FA lines pr oducing pipe products. Additionally, we note that in the 2011 voluntary survey industry had indicated that the test data for this subcategory were representative of other subcategories. Thus, the data available to us at proposal were only emissions test da ta for heavy density products. As earlier explained, CAA section 112(d)(3) requires the EPA to promulgate standards that must be at least as stringent as the average emissions limitation achieved by the best performing 12 percent of existing sources “for w hich the Administrator has emissions information.” ( The EPA typically has wide latitude in determining the extent of data

- gathering necessary to solve a problem. NRDC v. EPA , 529 F.3d 1077, 1086) (D.C. Cir. 2008) ). As subsequently explained in the 2013 proposal preamble (78 FR 22387, April 15, 2013), though we did not clearly state in the 2011 proposal that we were eliminating the subcategories for FA lines, this was our intent. The reason for eliminating these subcategories was that we determined that there was no longer any technical basis for distinguishing these subcategories.

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We also note that we confirmed with Johns Manville, who supplied all the F A line data, that the emission data was representative of emissions from all their FA products and thus suitable to use to calculate MACT floors.

126. Comment : One commenter (1042

- 0120/1042

- 0300/1042

- 0348) recommended agai nst the EPA setting limits for phenol and methanol because available data on phenol and methanol are very limited and the data were collected in different seasons. The commenter indicated that weather conditions could impact test results. The commenter rec ommended that the EPA use formaldehyde as a surrogate for phenol and methanol or, in the alternative, use liberal variability factors in setting limits for phenol and methanol.

Response : We disagree with the comment. Section 112(d)(3) of the CAA requires the EPA to promulgate standards for major sources of HAP that are based on MACT performance. For existing sources, MACT standards must be at least as stringent as the average emission limitation achieved by the best performing 12 percent of exist ing sources (for which the Administrator has emissions information) or the best performing 5 sources for source categories with less than 30 sources. For new sources, the MACT standards must be at least as stringent as the control level achieved in practic e by the best controlled similar source. CAA Section 112(d)(3). Section 112(d)(3) of the CAA does not address the question of whether, in assessing which sources perform best or are best controlled, emission levels should be evaluated either over time or i n a single test result. We believe, however, that our MACT floor calculation should identify the best performers, i.e., the best performing 12 per cent or best performing five sources in smaller source categories for existing sources, and the best controll ed single source for new sources, as those sources likely to emit the least HAP over time considering variability. Thus, the EPA does not believe that the statute requires or contemplates a random sample. Rather, use of data from the best performing source s is specified for developing the MACT floor limits. We note that the D.C. Circuit has held repeatedly that variability of best performing sources may be taken into account in establishing numeric MACT floors. Sierra Club , 479 F.3d at 881

- 882. (See also Na tional Lime Ass’n v. EPA , 627 F.2d 416, 431 n.46, 443(D.C. Cir. 1980)). In general, MACT standards are based on short term emissions test data because such data are derived from emissions tests conducted in response to CAA section 114 ICR. Because data may not represent the range of operating conditions that best performing sources face on a day

- to

- day basis EPA adjusts these short

- term data to account for the range of operating conditions. The varying conditions that the EPA is concerned with are variation s between tests at the same unit, and variations between the separate test runs that comprise a single test at the same unit. (A single test at a unit usually includes at least three separate test runs.). Between tests variability may be caused by differe nt setting for testing equipment, different people performing tests or different laboratories analyzing test results. These differences can lead to variations in results from different runs comprising the same test, which is known as within

- test variabilit y i.e., variability among the three separate test runs. In sum, each separate test run is a snapshot of actual performance that gives information about the normal and unavoidable variations in emissions that would be expected to occur over time. The EPA be lieves that the UPL calculation is a statistical formula designed to estimate a MACT floor level (including variability) that is equivalent to the average of the best performing sources based on future compliance tests. And that it is entirely appropriate to consider the variability within the best performing sources in developing emission limits based average performance of those sources. We also believe that if we did not account for variability in this manner and instead set the limit based solely on the

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average (mean) performance, then these units could exceed the limit half the time or more. The EPA agrees with the commenter that there are alternatives to the UPL statistics. But, we believe that because the floor calculations represent the average of th e best performing 12 percent of existing sources, it is reasonable for the EPA to use an appropriate statistical analysis to assess the impact both intra

- unit and inter

- unit variability have on the emissions profiles.

The final standards are based on test data provided by sources pursuant to a voluntary survey that they conducted. As explained in the November 2011and April 2013 proposals, the EPA had requested and the commenter agreed in a May 5, 2010 letter, that existing test data and testing data from a subset of facilities that were representative of emission sources from certain facilities would be submitted in response to the voluntary survey. In acknowledging this agreement, the commenter’s statements of May 5, 2010 indicated that the bases for
repres entativeness would include design type and size of process units or equipment, fuel type, operating temperatures, control devices and raw material content. (76 FR 72778 ; 78 FR 22379).

As also explained in our various proposals, the EPA proposed to disconti nue the use of formaldehyde as a surrogate for phenol and methanol. 76 FR 72788, 72791; 72796. The EPA may attribute characteristics of a subclass of substances to an entire class of substances if doing so is scientifically reasonable. Dithiocarbamate Task Force v. EPA , 98 F.3d 1394, 1399 (D.C. Cir. 1996). We no longer believe that there is a correlation and therefore, reasonable bases, between formaldehyde and phenol and methanol.

As also explained in section VI.C of the preamble to the final rule, we are establishing emission limits for formaldehyde, phenol and methanol at the MACT floor level of control even though there is an existing standard for formaldehyde in the current MACT rule. This is because in conducting our review, we also found that in the c urrent rule we had calculated a MACT floor for formaldehyde that was intended to be achievable by all existing sources.

In earlier responses, we have noted that we are not establishing new MACT standards for formaldehyde, phenol, and methanol emissions fro m RS manufacturing lines at wool fiberglass manufacturing facilities in this final action. We have issued an ICR under CAA section 114 to collect updated emissions and process information from the industry and we will analyze the ICR data and evaluate MACT limits for RS lines at wool fiberglass manufacturing facilities at a future date.

With regard to the commenter’s concern related to weather effects on testing, as explained earlier, we note that the commenter conducted a voluntary survey among all owners and operators of mineral wool production and wool fiberglass manufacturing facilities. The survey sought test data for PM, and HAP emissions, such as HF and HCl and information on process equipment, control devices, point and fugitive emissions, and pract ices used to control point and fugitive emissions. Further, the EPA requested and industry agreed in a May 5, 2010 letter, that a subset of facilities that were representative of emission sources from wool fiberglass industries would conduct testing and submit existing test data. The requirements in the final rule are based on test data submitted by the commenter

.

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127. Comment : One commenter (1042

- 0299) opined that the EPA has not sufficiently strengthened the formaldehyde limits, and argued that the EPA should consider the phase out of phenol

- formaldehyde binders as a new technology under technology review.

Response: As explained in earlier responses, CAA section 112(d) requires the EPA to promulgate standards for major sources of HAP based on the MACT performan ce. For existing sources, MACT standards must be at least as stringent as the average emissions limitation achieved by the best performing 12 percent of existing sources (for which the Administrator has emissions information) or the best performing 5 sourc es for source categories with less than 30 sources, as is the case here. For new sources, the MACT standards must be at least as stringent as the control level achieved in practice by the best controlled similar source. CAA Section 112(d)(3). As also earli er explained, the final standards are based on test data provided by sources pursuant to a voluntary survey that they conducted, which indicate the presence of formaldehyde despite indications that industry is phasing out its use. Our MACT floor calculatio ns are consistent with the CAA section 112(d) and can be found in the “ Revised Technical Approach for Wool Fiberglass Manufacturing MACT Floor Calculations” which is available in the docket. W e subsequently proposed and discussed our decision to revise the se emissions limits for based on our updated approach for evaluating limited data sets (also see the memorandum “ Approach for Applying the Upper Prediction Limit to Limited Datasets

– Wool Fiberglass Manufacturing ” for the updated approach for limited data sets).

128. Comment: One commenter (1041

- 0081) supported the EPA’s decision to set limits for previously uncontrolled emissions of formaldehyde, phenol and methanol for RS manufacturing lines and FA lines. The commenter cited that CAA section 112(d) requires th e EPA to set emission standards for all emitted pollutants. According to the commenter, closing loopholes and correcting problems that exist in the existing standard is an important part of the EPA’s job under CAA section 112(d)(6). The commenter believes that the EPA should ensure that these standards fully satisfy both CAA sections 112(d)(2) and (d)(3).

Response: The EPA acknowledges this support. Note that we are not establishing new MACT standards for RS manufacturing lines at wool fiberglass manufactu ring facilities in this final action. We have issued an ICR under CAA section 114 to collect updated emissions and process information from the industry and we will analyze the ICR data and evaluate MACT limits for RS lines at wool fiberglass manufacturing facilities at a future date. Subsequent responses below discuss specific details on the status of emission standards for flame attenuation manufacturing lines.

129. Comment: One commenter (1042

- 0120) noted that a significant shift in the use of

non

- PF binders had reduced enormously the residual risk remaining from formaldehyde. Therefore, the commenter contended that EPA is not justified in revising the formaldehyde limit.

Response : We disagree with the comment. As explained in our various proposals, the EPA pr oposed to discontinue the use of formaldehyde as a surrogate for phenol and methanol. 76 FR 72788, 72791; 72796. The EPA may attribute characteristics of a subclass of substances to an entire class of substances if doing so is scientifically reasonable. Di thiocarbamate Task Force v. EPA , 98 F.3d 1394, 1399 (D.C. Cir. 1996). We no longer believe that there is a correlation and therefore, reasonable bases, between formaldehyde and phenol and methanol.

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As also explained in the preamble to the final rule, we are establishing emission limits for formaldehyde, phenol and methanol at the MACT floor level of control because the existing standard for formaldehyde was calculated incorrectly. We also note that t he requirement to adopt MACT emission limitations, for e xample, applies without exception to “category or subcategory of major sources . . . of [HAP].” CAA section 112(d)(1). Regarding emission limits for RS lines, as discussed in section V. H of the preamble to the final rule, we are not establishing emission limits for RS manufacturing lines in this final action because we believe that the data no longer represent current industry conditions, most notably the significant reduction in the use of PF binders in wool fiberglass manufacturing. Consequently, we have issued a CAA section 114 ICR to obtain process and emissions data for RS manufacturing lines and we will evaluate MACT limits for these sources, based on the CAA section 114 ICR data, at a future date.

5. Compliance Schedule
130. Comment : One commenter (1042

- 0120/1042

- 0300/1042

- 0348) urged the EPA to adopt a 3

- year compliance period, with an option for facilities to petition for a 1

- year extension of time. The commenter (1042

- 0120) strongly objec ted to the EPA’s 90

- day deadline for compliance with requirements related to total chromium compounds. According to the commenter, 1 year is insufficient to design, obtain capital approval, purchase, construct, and install any additional control equipment. The commenter stated that companies cannot begin to design in advance of the final rule, given the known errors in the EPA’s floor and standard setting process as proposed in 2011. The commenter urged the EPA to consider granting further time, if necessar y, for the installation and implementation of control measures such as during a time when the furnace is idle and undergoing construction.

The commenter (1042

- 0300/1042

- 0348) contended that the EPA incorrectly concluded in its 2014 proposal that a furnace rebuild alone could achieve the chromium limit of 6.0E

- 05 pounds of chromium compounds per ton glass pulled and that proven emission controls currently exist. The commenter explained that compliance with this chromium limit will require additional time to implement the necessary experimental, unproven equipment (e.g., scrubbers) in the wool fiberglass industry, including facilitating research options including pilot programs, experimentation with different control systems, furnace design changes, and improv ements to existing control systems. The commenter invited the EPA to fund chromium emission reduction research programs for wool fiberglass furnaces.

Response : The compliance schedule for all finalized limits for existing major and area sources is 2 years from the effective date of this rule. The finalized chromium limit is 2.5E

- 04 pounds of chromium compounds per ton glass pulled, and the EPA has determined that rebuilding gas

- fired glass

- melting furnaces before degradation of the refractory causes elevat ed chromium emissions will be sufficient for facilities to meet this limit , as further discussed in section VI.B of the preamble to the final rule

. In the preamble to the 2014 proposal, we explained that standards promulgated under CAA section 112(f)(2) d o not apply until 90 days after the effective date of the final action amending this rule and sources may have up to 2 years after the effective date of the standard to comply, if the EPA finds that such period is necessary for the installation of controls . (CAA section 112(f)(2)(B).) We further explained that under CAA section 112(i)(3), the EPA must require sources to comply as expeditiously as practicable, but no later than 3 years after

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promulgation of the standard. ( Ass'n of Battery Recyclers v. EPA , 7 16 F.3d 667, (D.C. Cir. 2013). To establish the compliance schedule for major and new existing sources, we consulted our records from voluntary ICR responses and CAA section 114 responses regarding furnace ages and rebuilds, as well as statements by indust ry regarding furnace replacements. These sources of information indicated that the time period required to replace furnace refractory (for a complete furnace deconstruction and reconstruction) ranges from a few weeks (in the case of a “hot repair,” done wh ile the furnace is operating) to 20 months. According to industry information, existing sources subject to the phenol, formaldehyde, and methanol limits for FA lines are already equipped with control devices that can achieve the MACT floor limits, but may need to operate these devices more often than would be required to meet the limits of the 1999 MACT. Regarding chromium emission limits for gas

- fired furnaces, we are allowing the time period allowed by statute (up to 2 years). Existing sources may need to undertake such improvements as design, construction and installation of fans, ductwork, monitors and feed for add

- on controls, or may choose to replace their furnaces earlier than the furnace’s maximum expected lifetime. These activities cannot be accompl ished in 90 days, and 2 years is a reasonable amount of time to carry them out. Based on all of this information, we concluded that 2 years would be sufficient for sources to comply with the finalized standards. We see no reason for furnaces at area source s to require additional time for compliance not afforded to major sources, as there is no difference in the operation of the furnace itself as a result of major or area source status. If a major or area source were to require more than 2 years to comply wi th the finalized rule, then the owner or operator may request an extension under 40 CFR 63.1387(b).

Accordingly, the EPA has corrected regulatory text to reflect the applicable compliance dates, including revision of 40 CFR 63.1382(d) to remove the require ment to complete the initial performance test within 90 days of the effective date of the rule.

131. Comment: One commenter (1042

- 0120) supported the proposal to provide a categorical 1

- year compliance extension for sources covered by the CAA section 112(f)(2) residual risk standards. In other recent rules, the commenter stated that the EPA has adopted an unnecessarily constrained view of its authority to provide categorical extensions under CAA section 112(i)(3)(B), which is comparable to CAA section 112(f)(4)( B) in all relevant respects. The commenter believes that the better reading of CAA sections 112(f)(4)(B) and (i)(3)(B) is that, given adequate factual support, both provisions authorize the EPA to grant categorical compliance extensions. Therefore, the com menter supported this aspect of the proposal.

The commenter, however, contended that the EPA was mistaken in its assertion in the 2011 preamble that compliance with the CAA section 112(f)(2) standards must be required, in the first instance, no later than 90 days after the effective date of the rule. Although the EPA does not expressly say so in the proposal, the commenter stated that this assertion appears to be grounded in CAA section 112(f)(4)(A), which states that a standard adopted under CAA section 11 2(f) “shall not apply until 90 days after its effective date.” In contrast to the proposed wool fiberglass RTR, the commenter stated that the EPA set out a comprehensive and authoritative interpretation of CAA section 112(f)(4)(A) in the proposed RTR for t he “Hazardous Organic NESHAP.” The commenter opined that the interpretation therein is a correct assessment of the law and should be adopted in this and all other RTR rules.

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In the preamble to the proposed HON RTR, the commenter stated that EPA observed th at CAA sections 112(f)(4)(A) and (B) “are at odds with the rest of the statutory scheme governing compliance deadlines for section 112 rules in several respects.” The commenter noted that the EPA provided the following explanation of these inconsistencies:

• The 90

- day compliance deadline for existing sources in CAA section 112(f)(4)(A) directly conflicts with the up

- to

- 3

- year deadline in CAA section 112(i)(3)(A) allowed for existing sources subject to “any” rule under section 112.

• The CAA section 112(f)(4)( A) deadline results in providing a shorter deadline for ordinary existing sources to comply with residual risk standards than would apply under CAA section 112(i)(2) to new sources that are built after a residual risk standard is proposed but a more string ent version is promulgated.

• While both CAA section 112(i)(1), for new sources subject to any CAA section 112(d), (f), or (h) standard, and CAA section 112(i)(3), for existing sources subject to any CAA section 112(d) standard, refer to and rely upon the n ew title V permit program added in 1990 and explicitly provide for State permitting authorities to make relevant decisions regarding compliance and the need for any compliance extensions, CAA section 112(f)(4)(B) still reflects the pre

- 1990 statutory schem e in which only the Administrator is referred to as a decision

- making entity, notwithstanding the fact that even residual risk standards under CAA section 112(f) are likely to be delegated to States for their implementation, and will be reflected in source s’ title V permits and need to rely upon the title V permit process for memorializing any compliance extensions for those standards.

• “While we appreciate the fact that CAA section 112(i)(3)(B) refers specifically only to standards under CAA subsection 112( d), which some might argue means that CAA subsection 112(i)(3), in general, applies only to existing sources subject to section 112(d) standards, we believe that Congress inadvertently limited its scope and created a statutory conflict in need of our resol ution.”

The commenter noted that the EPA concluded that the requirements of CAA section 112(i)(3)(B) should take precedence over the conflicting provisions of CAA section 112(f)(4) and, as a result, proposed in the HON RTR to provide a three

- year complia nce period for sources covered by the proposed CAA section 112(f)(2) standards.

The commenter stated that the EPA’s interpretation in the HON RTR is not only persuasive, but correct. The commenter argued that the requirements of CAA section 112(f)(4)
are p lainly at odds with those of CAA section 112(i)(3) and the only rational way to resolve the inconsistencies is to implement the comprehensive and cohesive compliance deadline scheme outlined in CAA section 112(i). Thus, in the 2011 proposal , the commenter contended that the EPA should provide in the first instance a three

- year compliance period for sources covered by the CAA section 112(f)(2) standards and should consider granting further time if necessary for the installation and implementation of control measures.
Response: We acknowledge the commenter’s support for the 1

- year compliance period proposed in 2011 in 40 CFR 63.1387(a)(2)(i). As explained in response to comment number 131
,

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the compliance date for all emission limits being finalized is 2 years from the effective date of this rule.

With regard to the applicability of CAA section 112(i)(3), we have explained in more recent rules than the HON RTR mentioned by the commenter (e.g., Primary Lead RTR) that CAA section 112(i)(3) does not apply where we are setting the compliance date consistent with CAA section 112(f)(4). The EPA’s construct has recently been upheld in Ass'n of Battery Recyclers v. EPA

, 716 F.3d 667 (D.C. Cir. 2013) . “Although section 112(i)(3)’s three

- year maximum compliance period applies generally to ‘any emissions standard . . . promulgated under [section 112],’. . . section 112(f)(4)’s two

- year maximum applies more specifically to standards ‘under this section,’ i.e., section 112(f).” Id . at 672 (Alteration in original). We continue to believe that CAA section 112(f)(4) independently requires the agency to set a compliance date of 90 days and, as the commenter state s, specifies the basis for providing a longer compliance period of up to 2 years. Thus, at proposal we explained that CAA section 112(f)(4)(B) allows us to extend the compliance timeframe in circumstances where we believe that additional time is
necessary for installation of equipment or other measures to reduce HAP emissions.

We also note that we are promulgating emissions for chromium under both CAA sections 112(f)(2) and 112(d)(6). Consistent with CAA section 112(i)(3), standards developed under CAA section112(d)(6) would provide up to a 3

- year compliance date for existing sources. However, as explained in the EPA’s response to comment num ber 131 , the EPA is finalizing a 2

- year compliance period for both existing major and existing area sources.

132. Comm ent : One commenter (1042

- 0121) stated that compliance delays are unlawful and arbitrary. The commenter further stated that the EPA’s 2011 proposal to delay compliance with the new chromium limit for Wool Fiberglass for 1 year after the effective date would mean that local communities would have to wait until 2013 to receive protection from health risk. The commenter noted that the EPA proposed to delay compliance with the new MACT standards for both Wool Fiberglass and Mineral Wool for 3 years. The commente r asserted that facilities would be allowed to continue emitting manganese, lead, arsenic, nickel, and other HAP above the levels allowed by the proposed rules.

The commenter asserted that the proposed 1

- year compliance chromium limit date violates the pl ain text of CAA sections 112(f)(3) and (4), which require immediate compliance for new sources and a 90

- day compliance date for existing sources. The commenter stated that CAA section 112(f)(3) provides that ―[a]ny emission standard established pursuant to this subsection [section 112(f)] shall become effective upon promulgation. According to the commenter, CAA section 112(f)(4) establishes a prohibition on violating the new standard, stating that ―[n]o air pollutant to which a standard under this subsectio n applies may be emitted from any stationary source in violation of such standard, except that in the case of an existing source . . . such standard shall not apply until 90 days after its effective date. Thus, the commenter claimed that the statute establ ishes an immediate compliance date for new sources and a 90

- day compliance date for existing sources. The commenter asserted that, for existing sources only, the statute provides the following: the Administrator may grant a waiver permitting such source a period of up to 2 years after the effective date of a standard to comply with the standard if two statutory factors are met for a particular source. The commenter argued that the EPA may grant such a waiver only if (1) the Administrator finds that such per iod is necessary for

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the installation of controls

, and (2) that steps will be taken during the period of the waiver to assure that the health of persons will be protected from imminent endangerment.

The commenter observed that the statute creates a waiver process for an existing source to apply for an extension of the date, if it can meet the statutory factors. To implement that requirement, the commenter argued that the EPA’s own regulations have established an application process where an individual facil ity unable to comply with a relevant standard under CAA section 112(f) may file an application for a 2

- year extension of compliance after the standard’s effective date to comply with the standard. The commenter noted that the regulation follows the languag e of the statute. The commenter asserted that the regulation also provides a specific list of information that an application for a compliance extension must include and that the EPA should consider, including specific details on the compliance plan and th e need for an extension.

According to the commenter, neither the statute nor the EPA’s own regulation authorize the EPA to use the national rulemaking process to grant a CAA section 112(f)(4) waiver to an entire source category of facilities, absent any a pplication. There is no indication in this record that any waiver application has been submitted to the EPA. In order for the EPA to consider such a waiver, a facility must submit a request for that waiver with supportive evidence. The EPA should evaluate that request on a case

- by

- case basis, with full notice and comment from the local community. Using the national rule process to delay compliance is arbitrary and capricious and an abuse of discretion.

Moreover, the commenter contended that the EPA’s propos al to delay the chromium limit also violates CAA section 112(f)(4) because the EPA has failed to satisfy the required statutory factors. The commenter claimed that the EPA’s record includes no evidence that the statutory factors are met. The commenter note d that the proposed rule simply states that we are proposing that a 1

- year compliance timeframe is necessary so that affected facilities have adequate time to install additional controls and demonstrate compliance. The commenter claimed that the agency’s b elief is not sufficient to satisfy the statute when it has the burden of proof.

The commenter argued that the second statutory factor also bars the compliance delay proposed by the EPA. The commenter contended that there is no evidence in the record that

n ecessary steps will be taken during the additional year to assure that the health of persons will be protected from imminent endangerment. According to the commenter, there is evidence of endangerment for this source category that makes it particularly dan gerous, among major source categories. The commenter concluded that the EPA has the burden to prove that allowing the delay will avoid imminent endangerment.

Although it is not the commenter’s burden to show this, there are many reasons to be concerned about imminent endangerment during the year the EPA proposes to delay compliance. First, although the EPA has not recognized this, the commenter noted that existing health risk from the Wool Fiberglass Manufacturing source category is currently unacceptabl e, and the EPA’s own auxiliary analysis shows that even the EPA believes it is likely to become much worse if EPA does not finalize a chromium limit. Per the commenter, every additional day that the EPA allows children to be exposed to these unacceptable h ealth risks is itself indefensible. Second, because of the history of exposure to chromium, mercury, and other PB

- HAP in the

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affected communities, the commenter contended that there is an even greater health risk from each additional day of exposure than t here would be if none of the pollutants were PB

- HAP. Third, the commenter asserted that there is an indication of socioeconomic disparities for the Wool Fiberglass Manufacturing source category which shows the affected communities are likely to be more vul nerable and less equipped to handle the increased health risk from this source category. In view of this, the commenter asserted that the EPA may not lawfully delay compliance without assuring public health protection during the delay period, and therefore the proposed rule is also unlawful on this basis.

The commenter asserted that by failing to begin this rulemaking for so long, the EPA has already delayed satisfying its legal duties both under CAA sections 112(f)(2) and (d)(6) to provide protection for a ffected local communities. The commenter argued that these provisions actually required the EPA to perform this rulemaking and set the required standards no later than 8 years after the MACT standards were first promulgated. According to the commenter, thi s occurred in 1999, and this rulemaking duty became due in 2007. The commenter observed that the EPA did not propose this rule until 2011. The commenter argued that the EPA should not deny local communities vital protection they need for an additional 2 ye ars when the EPA was obligated to promulgate this rule more than 4 years ago. According to the commenter, the EPA has no lawful justification, in view of the statutory context and these circumstances, to delay the compliance date any longer.

Per the commen ter, in enacting the provision governing the compliance schedule for CAA section 112(d), which is 42 U.S.C. section 7412(i), Congress stated it wanted “expeditious” compliance. The commenter observed that this principle also applies to CAA section 112(f)(4 ), 42 U.S.C. section 7412(f)(4). There, the commenter noted that the statute has established a “prohibition on non

- compliance by existing sources after the 90

- day period, unless a waiver of up to 2 years is specifically granted based on the statutory facto rs provided.” Moreover, the commenter asserted that Congress intended for similarly “expeditious compliance with the deadline set by section 112(f)(4), and ―[w]here Congress explicitly enumerates certain exceptions to a general prohibition, additional exce ptions are not to be implied, in the absence of a contrary legislative intent.”

For these reasons, the commenter argued that the compliance delay for the residual risk standard for chromium is arbitrary and capricious, and without the required evidentiary support in the record.

The commenter continued that EPA’s proposed 3

- year delay for the new MACT standards is also unlawful for reasons similar to those described above. In addition, the commenter argued that EPA also has not met the standard under section 112(i)(3) to demonstrate that a MACT compliance date for existing sources ―shall provide for compliance as expeditiously as practicable. According to the commenter, not only is there no evidence of this required determination in the record, but also EPA c annot meet this test because it is ensuring no additional protection for communities in the meantime.

Response: As explained in the EPA’s response to comment number 13 2 , we believe that CAA section 112(i)(3) does not apply where we are setting the complian ce date consistent with CAA section 112(f)(4). The EPA is not ignoring the requirements of CAA sections 112(f)(3) and

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(4). Section 112(f)(4)(B) of the CAA is a direct grant of authority, which can be implemented not just by regulation but by other EPA acti on, as done here. The EPA considered how much time would be required by industry to comply with the finalized standards, and concluded that 2 years would be sufficient.

We also note that we are promulgating emissions for chromium under both CAA sections 1 12(f)(2) and (d)(6). Consistent with CAA section 112(i)(3), standards developed under CAA section 112(d)(6) would provide up to a 3

- year compliance date for existing sources. However, as explained in the EPA’s response to comment number 131 , the EPA is fin alizing a 2

- year compliance period for both existing major and existing area sources.

133. Comment : One commenter (1042

- 0300) requested that the EPA extend the compliance deadline to coincide with currently planned furnace rebuilds for each facility rather tha n the compliance date one year from promulgation of the standards, due to the cost of unplanned furnace rebuilds. The commenter added that the cost of an oxyfuel or air

- gas furnace rebuild is on the order of between $7

- 10 million, depending on size and mat erials. If a company has recently undertaken a furnace rebuild at this cost, that cost would recur for a company to reconstruct the furnace within a year after promulgation of this rule.

Response : The final rule requires owners or operators to demonstrate initial compliance with the chromium emissions limit for existing sources within 2 years of the effective date of the rule and to conduct emissions test each year thereafter. A furnace rebuild would be needed only if a furnace can no longer achieve the ch romium limit, regardless of age.

6. Economic Impacts
134. Comment : One commenter (1042

- 0120) argued that the emission limits proposed in 2011 (76 FR 72770) for new and reconstructed sources (PM, formaldehyde (RS lines only), phenol (RS lines only), and methanol ( RS lines only)) would have a devastating impact on many wool fiberglass manufacturing companies, and that the EPA’s economic impacts analysis did not address this cost. The commenter claimed that companies estimate $1 million or more per source to install this equipment. The commenter opined that the EPA was mistaken in its 2011 proposal in assuming that existing sources could meet the 2011 proposed limits without using additional controls not considered by the EPA in its cost analysis (wet or dry scrubbers in addition to the existing control devices). With regard to the proposed limits for phenol, formaldehyde, and methanol for RS manufacturing lines, the commenter stated that these limits cannot be achieved even by sources using non

- PF binders.

The commen ter asserted that such an outcome is inconsistent with the legislative history of the CAA , which makes clear that the MACT standards were not intended to force the shutdown of facilities. H.R. Rep. No. 101

- 490, at 335 (1990) (“MACT is not intended to . . . drive sources to the brink of shutdown.”) S. Rep. No. 101

- 228, at 152 (1989) (“Controls which are so expensive that they force closure of the source or would severely impair its continuation as an economic entity are not ‘available.”)

Response: As previou sly explained, CAA section 112(d) requires EPA to promulgate standards for major sources of HAP based on the performance of the maximum achievable control technology. For existing sources, MACT standards must be at least as stringent as the

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average emissio ns limitation achieved by the best performing 12 percent of existing sources (for which the Administrator has emissions information) or the best performing 5 sources for source categories with less than 30 sources, as is the case here. For new sources, the MACT standards must be at least as stringent as the control level achieved in practice by the best controlled similar source. CAA Section 112(d)(3). The EPA is not allowed to consider costs in setting MACT standards. National Lime Ass’n v. EPA , 233 F.3d at 640.

Regarding the emission limits for formaldehyde, phenol, and methanol for RS lines proposed in the November 25, 2011 notice, we do not believe that the available data for RS manufacturing lines are sufficient for EPA to establish appropriate emissio n limits

. Consequently, we have issued a CAA section 114 ICR to wool fiberglass facilities to obtain process and emissions data for RS manufacturing lines. We will analyze ICR data and evaluate MACT floor limits for RS lines at a future date. See section V.H of the preamble to the final rule for a more detailed discussion regarding the status of RS lines.

Regarding the comment that the EPA did not include in its economic impacts analysis the control technologies needed to meet the PM limit, th e EPA has revised the PM limits since the 2011 proposal (76 FR 72770, November 25, 2011). The final PM limit is 0.33 pounds per ton of glass pulled. As noted in the November 13 2014 supplemental proposal (79 FR 68026), we believe that all facilities will b e able to comply with the final PM emission limit based on the data submitted to EPA.

Price elasticities of demand and supply obtained by the EPA and included in the economic impact analysis report show that consumers of wool fiberglass products will inc ur some of the costs of this rule in the form of increases in price. Thus, producers will not incur the entirety of the costs of this rule, and should not bear large enough costs to lead to facilities or firms being at risk of closure or other substantial economic impacts based on the EPA’s estimates of the compliance costs. Refer to the EPA’s responses to comment number 101 for further discussion of the technology basis for the final PM standard and the memorandum “Economic Impact and Small Business Analys is

– Mineral Wool and Wool Fiberglass RTRs and Wool Fiberglass Area Source NESHAP,” which is available in the docket, for further discussion of the economic analysis

.

135. Comment : One commenter (1042

- 0120) argued that the EPA’s justifying the cost

effectivenes s values supporting the 2011 proposed chromium limit by comparing compliance costs to annual sales or revenues of the affected companies is arbitrary and fails to provide a reasoned basis for the proposed standards because gross sales have no necessary rel ationship to the financial viability of the affected company. The commenter cited the EPA’s rationale for the
cost

- effectiveness values for the 2011 proposed chromium limit (76 FR 72770, November 25, 2011): “The economic impact on [affected] firms measured in annual compliance costs as a percent of sales or revenues, is less than 0.001 percent for each of the affected firms.” According to the commenter, many companies with very high sales are highly unprofitable. The commenter concluded that sales alone pro vide no insight into the ability of the affected company to reasonably bear the cost of compliance. In addition, the commenter argued that the use of revenues as a measure of cost effectiveness is arbitrary because the level of emissions control that might be required would depend on the profitability of the affected companies. The commenter concluded that, therefore, if an industry happens to be doing well financially at the

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time the EPA conducts an RTR rulemaking, the industry could be regulated much more stringently than if the same industry happened to be doing poorly at the time the rules are developed.

Response: The economic impact analysis mentions that the change in product price associated with the impact of the rule is “approximated by the cost to revenue ratio, since this ratio is the maximum price change that producers may face” to recover from consumers all costs of the rule. In addition, the a gency never uses revenue data as part of estimating the cost

effectiveness of its rules since the cost

- effectiveness is, by definition, the annualized cost of control divided by emissions reduction, and does not consider revenue data. The EPA used sales rather than profits in its economic impact analysis since the sales data is more complete and accurate th an profit data for individual companies, data that often incorporates provisions of tax laws than may yield estimates of prof i t that do not reflect the true economic profit experienced by companies. Price elasticities of demand and supply obtained by the E PA are used in the economic impact analysis to show that consumers of wool fiberglass products will incur some of the costs of this rule in the form of increases in price. Thus, producers will not incur the entirety of the costs of this rule, and should no t bear large enough costs to lead to facilities or firms being at risk of closure or other substantial economic impacts based on the EPA’s estimates of the compliance costs and our economic impact analysis . That being said, the a gency is mindful of the pot ential impact of this rule upon wool fiberglass producers and their consumers regardless of the financial condition of such producers and consumers.

We also note that we found $11,000 per pound chromium removed to be a reasonable cost in the final Chromiu m Electroplating RTR rulemaking, where we regulated chromium compounds (77 FR 59220, September 19, 2012). Thus, contrary to the commenter’s assertion the
cost

- effectiveness for this rule is not in excess of the cost effectiveness values the EPA has found

a cceptable in prior CAA section 112 cost effectiveness analyses. Moreover, CAA section 112(d) neither specifies nor mandates a cost methodology. In Husqvrna AB v. EPA, 254 F.3d 195, 200 D.C. Cir. 2001), the D.C. Circuit found EPA’s chosen methodology “reaso nable” because the statute “did not mandate a specific method of cost analysis.”

136. Comment : Two commenters (1042

- 0300/1042

- 0348, 1042

- 0120) argued that the EPA’s cost effectiveness measure for chromium using dollars per pound pollutant is unreasonable becaus e in other rules the EPA has used a ‘dollars per ton pollutant removed’ metric to evaluate cost effectiveness. The commenter believes the EPA has artificially deflated the true cost effectiveness of the emission reductions by employing the dollars per poun d pollutant metric, and if the a gency used the dollars per ton metric, as in the 1999 MACT rule, the limits proposed by the EPA would have been rejected as too costly.

Response : Regarding the commenter’s assertion that our cost effectiveness measure is

u nreasonable, we disagree. For highly toxic pollutants such as hexavalent chromium, mercury, and lead, we use unit of measure dollars spent per pound of pollutant removed. As earlier explained, the cost

- effectiveness for the chromium compound limit in the f inal rule is consistent with the approach the EPA has taken in numerous rulemakings including the RTRs for chromium electroplating industr y . W e also note that we found $11,000 per pound chromium removed to be a reasonable cost in the final Chromium Electroplating RTR rulemaking, where we regulated chromium compounds (77 FR 59220, September 19, 2012). Thus, contrary to the

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commenter’s assertion

, the cost

- effectiveness for this rule is not in excess of the cost effectiveness values the EPA has found ac ceptable in prior CAA section 112 cost effectiveness analyses. Moreover, CAA section 112(d) neither specifies nor mandates a cost methodology. In Husqvrna AB v. EPA, 254 F.3d 195, 200 D.C. Cir. 2001), the D.C. Circuit found EPA’s chosen methodology “reason able” because the statute “did not mandate a specific method of cost analysis.”

137. Comment : One commenter (1042

- 0300/1042

- 0348) stated that the proposed increase in the testing duration for Method 316 from one to two hours will add cost that the EPA did not f actor into its estimated rule cost burden.

Response : Consistent with our proposal, we are finalizing, as proposed, the requirement to collect a minimum sampling volume of 2 dscm; however, we are not finalizing the proposed minimum sampling run time for EP A Method 316 of 2 hours . In the final rule, the EPA is specifying the use of Method 31 8 for measuring concentrations of formaldehyde, methanol, and phenol. The final rule also allows facilities use the options of using either (1) Method 31 6 for formaldehyd e , or (2) Method 30 8 for methanol. The EPA’s testing cost estimate is based on the use of Method 318 rather than Method 316.

138. Comment : One commenter (1042

- 0348) argued that the EPA, in changing applicability for FA lines to lines not previously regulated, h as not considered this expansion in its cost estimates, which is required by law expands applicability to lines not previously regulated. The EPA’s new applicability language will affect the competitiveness of lines not previously regulated.

Response : As p reviously explained, CAA section 112(d) requires the EPA to promulgate standards for major sources of HAP based on the performance of the maximum achievable control technology. For existing sources, MACT standards must be at least as stringent as the

avera ge emissions limitation achieved by the best performing 12 percent of existing sources (for which the Administrator has emissions information) or the best performing 5 sources for source categories with less than 30 sources, as is the case here. For new so urces, the MACT standards must be at least as stringent as the control level achieved in practice by the best controlled similar source. CAA Section 112(d)(3). The EPA is not allowed to consider costs in setting MACT standards. National Lime Ass’n v. EPA

, 233 F.3d at 640. As also earlier explained, the 1999 MACT standard for the Wool Fiberglass Manufacturing source category included no control floors for existing sources making light density, automotive and heavy density products on FA line s . But , the EPA h as a “clear obligation to set emissions standards for each listed HAP.” National Lime v. EPA , 233 F. 3d at 634. As also explained earlier, the existing source limits for formaldehyde were set at the highest measured value for each of the subcategories. Aga in, the D.C. Circuit has consistently rejected the EPA’s construct of CAA section 112(d) as requiring standards that can be achieved by all sources. “EPA may not deviate from section 7413(d)(3)’s requirement that floors reflect what the best performers actually achieve by claiming that floors must be achievable by all sources u sing MACT technology.” Cement Kiln Recycling Coalition v. EPA , 255 F.3d at 861. Thus, in addition to setting no control floors, the emission limits were set not at the level defined by the MACT floor, but at a level that was achievable by all sources withi n the wool fiberglass manufacturing source category.

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We based our cost estimate for FA lines on the process and emissions data submitted by industry in response to voluntary surveys and information collection requests under CAA section 114. As discussed in the April 15, 2013 supplemental proposal (78 FR 22388), based on the industry

- supplied data, we do not believe that the subcategories for FA lines in the 1999 NESHAP continue to have a technical basis. Based on the data submitted, we also do not believe
t hat our cost estimate for FA lines did not cover all FA lines that will be subject to the final rule and the commenter did not provide any data or information that would substantiate the claim that previously

- unregulated FA lines would be covered under the final rules.

7. MACT Floor Analyses
139. Comment: One commenter (1042

- 0120), in response to the 2011 proposal, highlighted that the EPA cannot simply change its mind about what standards are required to comply with CAA sections 112(d)(2) and (3), nor can it recalculate a MACT floor based on subsequent pe rformance. Cf. NRDC v. EPA , 529 F.3d 1077, 1084 (D.C. Cir. 2008) (rejecting contention that CAA section 112(d)(6) requires the EPA to “start from scratch” and develop new MACT standards).

Response: We disagree with the comment. The D.C. Circuit has held th at the EPA may permissibly amend improper MACT determinations, including amendments to improperly promulgated floor determinations, using its authority under CAA sections 112 (d) (2) and (3). Medical Waste Institute v. EPA , 645 F.3d 420, 425

- 27 (D.C. Cir. 2011). (Resetting MACT floor, based on post

- compliance data, permissible when originally

- established floor was improperly established, and permissibility of the EPA’s action does not turn on whether the prior standard was remanded or vacated). Similarly, P ortland Cement Ass’n v. EPA , 665 F.3d 177, 189 (D.C. Cir. 2011) confirms that CAA section 112 (d)(6) does not constrain EPA and it may reassess its standards more often, including revising existing floors if need be.

We note that in this instance, we had improperly promulgated a floor determination in 1999 for formaldehyde as well as a surrogacy requirement that lacked correlation (76 FR 72775)

. (The EPA may attribute characteristics of a subclass of substances to an entire class of substances if doing so is scientifically reasonable. Dithiocarbamate Task Force v. EPA , 98 F.3d 1394, 1399 (D.C. Cir. 1996)). Put another way, if the EPA did not adopt a proper MACT standard initially, it is not amending a MACT standard but adopting one for the first time. That was the case for formaldehyde, methanol, and phenol emissions in the 2011 proposal. Here, the EPA either adopted no MACT standard at all for these HAP or improperly promulgated a floor determination for formaldehyde, which is an approach soundly rejected b y the D.C. Circuit in both National Lime

, 233 F.3d at 633

- 34 and in Portland Cement Ass’n v. EPA , 665 F.3d at 189

. Therefore, the EPA is not barred from making MACT floor determinations and issuing MACT standards for formaldehyde, phenol, and methanol purs uant to CAA sections 112 (d)(2) and (3).

As also previously explained, in several recent rulemakings, we have chosen to fix underlying defects in existing MACT standards under CAA sections 112(d)(2) and (3), provisions that directly govern the initial pro mulgation of MACT standards (see National Emission Standards for Hazardous Air Pollutants From Petroleum Refineries, October 28, 2009, 74 FR 55670; and National Emission Standards for Hazardous Air Pollutants: Group I Polymers and Resins; Marine Tank Vesse l Loading Operations; Pharmaceuticals Production; and the Printing and Publishing Industry, April 21, 2011, 76 FR 22566). We believe that our approach is

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reasonable because using those provisions ensures that the process and considerations are those associ ated with initially establishing a MACT standard, and it is reasonable to make corrections following the process that would have been followed if we had not made an error at the time of the original promulgation.

Note that we are not finalizing in this fin al action MACT standards for formaldehyde, phenol, and methanol for RS manufacturing lines at wool fiberglass manufacturing facilities. We have issued an ICR under section 114 of the CAA to collect updated emissions and process information from the industr y, and we will analyze the ICR data and evaluate MACT limits for RS lines at wool fiberglass manufacturing facilities at a future date. Refer to section V. H of the preamble to the final rule for further discussion of the EPA’s rationale for postponing
esta blishing MACT standards for formaldehyde, phenol, and methanol emission data for RS lines until a future date and for issuing an ICR for additional data.

140. Comment : One commenter (1042

- 0348) opined that “cherry picking” the best data individually for formald ehyde, phenol, and methanol results in unachievable limits because it does not account for the relationship among formaldehyde, phenol, and methanol and their use together in the insulation binding process. The commenter further argued that, according to t he EPA’s database, very few units are best performers for more than one pollutant, meaning that the proposed standards reflect the performance of exceedingly few actual sources. The commenter claimed that the EPA has improperly exercised its discretion in this rule and has failed to provide an assessment of how many actual fiber glass furnaces or lines will be able to meet the proposed standards without taking any further control measures.

Response : The EPA disagrees with the commenter who believes MACT flo ors cannot be set on a pollutant

- by pollutant basis. Regarding determination of the MACT floor, and as earlier explained in various responses, above, the intent of CAA s ection 112(d)(3) is to bring all industry into compliance with the emission limits achi eved by the best performing sources across the industry. As also explained earlier, the D.C. Circuit has consistently rejected a reading of “achieved by the best performers,” in CAA section 112(d)(3) as meaning achievable by all sources within a source cat egory. “EPA’s rationales . . . amount to nothing more than concern about ensuring that its floor is achievable by all kilns in the subcategory

-- precisely the position we rejected in Cement Kiln.” Sierra Club v. EPA , 479 F.3d at 881. See also, Cement Kiln Recycling Coalition v. EPA , 255 F.3d at 861 “EPA may not deviate from section 7413(d)(3)’s requirement that floors reflect what the best performers actually achieve by claiming that floors must be achievable by all sources using MACT technology.” (“EPA ca nnot circumvent Cement Kiln’s holding that section 7412(d)(3) requires floors based on the emission level actually achieved by the best performers(those with the lowest emission levels), not the emission level achievable by all sources, simply by redefinin g “best performing” to mean those sources with emission levels achievable by all sources.” Sierra Club v. EPA , 479 F. 3d at 881. (Emphasis in original)).

Contrary to the commenter’s suggestion, CAA section 112(d)(3) does not mandate a total facility approa ch. A reasonable interpretation of CAA section 112(d)(3) is that MACT floors may be established on a HAP

- by

- HAP basis, so that there can be different pools of best performers for each HAP. Indeed, as illustrated below, the total facility approach is not

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co mpelled by the statutory language but can lead to results so arbitrary that the approach may simply not be legally permissible.

S ection 112(d)(3) of the CAA is ambiguous as to whether the MACT floor is to be based on the performance of an entire source or on the performance achieved in controlling particular HAP. Congress specified in CAA section 112(d)(3) the minimum level of emission reduction that could satisfy the requirement to adopt MACT. For new sources, this floor level is to be “the emission contro l that is achieved in practice by the best controlled similar source.” For existing sources, the floor level is to be “the average emission limitation achieved by the best performing 12 percent of the existing sources” for categories and subcategories with 30 or more sources, or “the average emission limitation achieved by the best performing 5 sources” for categories and subcategories with fewer than 30 sources. The language of the CAA section 112(d) does not address whether floor levels can be established HAP

- by

- HAP or by any other means. The reference to “sources” does not lead to the assumption commenters make that the best performing sources can only be the best

- performing sources for the entire suite of regulated HAP. Instead, the language can be reaso nably interpreted as referring to the source as a whole or to performance as to a particular HAP. Similarly, the reference in the new source MACT floor provision to “emission control achieved by the best controlled similar source” can mean emission control as to a particular HAP or emission control achieved by a source as a whole.

Also, CAA section 112(d) includes language such as “existing source,” “best performing,” and “achieved in practice” in referring to sources’ actual operations, but again the langu age says nothing about whether it is referring to performance as to individual HAP or to single facility’s performance for all HAP. The argument that MACT floors set HAP

- by

- HAP are based on the performance of a hypothetical facility, so that the limitation s are not based on those achieved in practice, also just re

- begs the question of whether CAA section 112(d)(3) refers to whole facilities or individual HAP. All of the limitations in the floors in this rule of course reflect sources’ actual performance and were achieved in practice. The commenter also points to the EPA’s subcategorization authority, and claims that because Congress authorized the EPA to distinguish among classes, types, and sizes of units, the EPA cannot distinguish units by individual poll utant, as they allege the EPA did in the proposed rule. However, that statutory language addresses the EPA’s authority to subcategorize sources within a source category prior to setting standards. In doing so, the EPA does not distinguish within each subca tegory based on HAP emitted. Rather, it establishes emissions standards based on the emissions limits achieved by units in each subcategory. Therefore, the EPA’s subcategorization authority is irrelevant to the question of how the EPA establishes MACT floo r standards once it has made the decision to distinguish among sources and create subcategories.

The EPA’s long

- standing interpretation of the CAA is that the existing and new source MACT floors are to be established on a HAP

- by

- HAP basis. One reason for t his interpretation is that a whole plant approach could yield least common denominator floors

– that is floors reflecting mediocre or no control, rather than performance which is the average of what best performers have achieved. See 61 FR 173687 (April 19 , 1996); 62 FR 48363

- 64 (September 15, 1997) (same approach adopted under the very similar language of CAA section 129 (a)(2)). Such an approach would allow the performance of sources that are outside of the best

- performing 12 percent for certain pollutant s to be included in the floor calculations for those same pollutants, and it is even conceivable that the worst performing source for a pollutant could be considered a

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best performer overall, a result Congress could not have intended. Inclusion of units th at are outside of the best performing 12 percent for particular pollutants would lead to emission limits that do not meet the requirements of the statute.

For example, if the best performing 12 percent of facilities for HAP metals were also the worst perfo rming units for acid gas HAP, the floor for acid gases or metals would end up not reflecting best performance. In such a situation, the EPA would have to make some type of value judgment as to which pollutant reductions are most critical to decide which so urces are best controlled. Such value judgments are antithetical to the direction of the statute at the MACT floor

- setting stage.

The central purpose of the amended air toxics provisions was to apply strict technology

based emission controls on HAP. See, e.g., H. Rep. No. 952, 101st Cong. 2d sess. 338. The floor’s specific purpose was to assure that consideration of economic and other impacts not be used to “gut the standards. Although costs are by no means irrelevant, they should by no means be the determ ining factors. There needs to be a minimum degree of control in relation to the control technologies that have already been attained by the best existing sources.” A Legislative History of the Clean Air Act, Vol. II at 2897 (statement of Rep. Collins). An interpretation that the floor level of control must be limited by the performance of devices that only control some of these pollutants effectively “guts the standards” by including worse performers in the averaging process, whereas the EPA’s interpretatio n promotes the evident Congressional objective of having the floor reflect the average performance of best performing sources. Because Congress has not spoken to the precise question at issue and the a gency’s interpretation effectuates statutory goals and policies in a reasonable manner, its interpretation must be upheld. See Chevron v. NRDC , 467 U.S. 837 (1984).

The EPA notes, however, that if optimized performance for different HAP is not technologically possible due to mutually inconsistent control tech nologies (for example, if metals performance decreased if organics reduction is optimized), then this would have to be taken into account by the EPA in establishing a floor (or floors). The Senate Report indicates that if certain types of otherwise needed controls are mutually exclusive, the EPA is to optimize the part of the standard providing the most environmental protection. S. Rep. No. 228, 101st Cong. 1st sess. 168 (although, as noted, the bill accompanying this Report contained no floor provisions). It should be emphasized, however, that, “the fact that no plant has been shown to be able to meet all of the limitations does not demonstrate that all the limitations are not achievable.” Chemical Manufacturers Association v. EPA , 885 F. 2d at 264 (upholdi ng technology

- based standards based on best performance for each pollutant by different plants, where at least one plant met each of the limitations but no single plant met all of them).

Finally, we note that the D.C. Circuit recently found a challenge to the a gency’s practice of setting floors based on emissions levels achieved by the best performing units on a pollutant

by

- pollutant basis to be barred on jurisdictional grounds. Medical Waste Institute v. EPA , 645 F. 3d 420 (D.C. Cir. 2011).

We also note t hat the final rule limits are based on data that industry submitted to the

a gency pursuant to a voluntary survey they requested and conducted.

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Regarding the proposed formaldehyde, methanol, and phenol limits for RS lines, as noted in section V.H of the pre amble to the final rule, we are not establishing MACT standards for RS manufacturing lines at wool fiberglass manufacturing facilities in this final action. We have issued an ICR under CAA section 114 to collect updated emissions and process information fr om the industry and we will analyze the ICR data and evaluate MACT floor limits for RS lines at wool fiberglass manufacturing facilities at a future date.

8. Environmental Justice
141. Comment : One commenter (1042

- 0121) opined that the EPA’s environmental justice (EJ) analysis is incomplete and the EPA should include the following additional elements to assess environmental justice impacts:

• Assess the baseline “overall health” status and cancer levels of individuals and communities.

• Follow the recommendations of t he EPA’s interim guidance found in the Environmental Justice Strategic Enforcement Assessment Tool (EJSEAT).

• Include statistics on the percentages of population with limited English proficiency, infant mortality, and low birth weight.

T he commenter stated that socioeconomic disparity in health risk from the Wool Fiberglass Manufacturing source category makes the risk the EPA has found unacceptable, and the EPA should finalize a rule that is consistent with the principle of environmental justice. According t o the commenter, the EPA’s socioeconomic analysis for the Wool Fiberglass Manufacturing source category finds disproportionate impacts on minorities and people below the poverty level. The commenter noted that this document indicates that the demographic r esults for the population potentially impacted by wool fiberglass emissions indicate that the Minority, African American, Other and Multiracial, and Hispanic or Latino percentages are higher than their respective national percentages (by 11, 7, 5, and 2 pe rcentage points, respectively).

Response: Where the agency finds risks to be acceptable, the EPA’s obligation under EO 12898 is to ensure that no group is subject to adverse impacts. The agency conducts its risk assessments based on the risks posed to the general population which includes ethnic a nd socio economically disadvantaged communities. Where we find those risks to be acceptable no further action is warranted. For the Wool Fiberglass Manufacturing source category, we determined that the current health risks posed by emissions from the sourc e category are acceptable. However, there are about 1
, 20 0 ,000 people nationwide that are currently subject to health risks which are

non

- negligible (i.e., cancer risks greater than 1

- in

- 1 million) due to emissions from this source category. We performed an analysis of the demographic makeup of these 1
, 2 0 0 ,000 people. The demographic distribution of this ‘‘at

- risk’’ population is similar to the national distribution of demographics for all groups except for the ‘‘minority’’ group (defined as total population minus the white population), which is 1 6 percent greater than its corresponding national percentage. See the Risk and Technology Review

— Analysis of Socio

- Economic Factors for Populations Living Near Wool Fiberglass Facilities dated March 23, 2015 in the d ocket for additional details on the demographic analysis. The EPA has determined that the current health risks posed by emissions from this source category are acceptable.

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With respect to the EJSEAT tool, it is currently a draft tool in development and ha s not undergone a sufficient level of peer review. Additionally, EJSEAT is a simple screening tool whereas the aforementioned demographic distributions of “at

- risk” populations reflect a much more thorough examination of populations.

Regarding the comment that the EPA should assess the baseline “overall health” status and cancer levels of individuals and communities, in our Risk and Technology Review

— Analysis of Socio

- Economic Factors for Populations Living Near Wool Fiberglass Facilities we looked at the percentages of the “at

- risk” population that were “Over 25 without a high school diploma” and that were considered to be in “Linguistic Isolation.” We found that the percentages in these demographic categories in the “at

- risk” population were similar to th e percentages in the national population.

Regarding the comment that the EPA should include statistics on the percentages of population with limited English proficiency, in our Risk and Technology Review

— Analysis of Socio

- Economic Factors for Populations L iving Near Wool Fiberglass Facilities we looked at the percentages of the “at

- risk” population that were “Over 25 without a high school diploma” and that were considered to be in “Linguistic Isolation.” We found that the percentages in these demographic ca tegories in the “at

- risk” population were similar to the percentages in the national population.

Regarding the comment that the EPA should include statistics on the percentages of the population with infant mortality and low birth weight, in our Risk and T echnology Review

— Analysis of Socio

- Economic Factors for Populations Living Near Wool Fiberglass Facilities we looked at the percentages of the “at

- risk” population that were between the ages of “0 to 17.” We found the percentage of the population in the “0 to 17” demographic category to be identical in the “at risk” population and the national population. In a ddition, the risk assessment for this source category considers the groups that may be most at

- risk. When the EPA derives exposure reference concentrations and unit risk estimates for HAP, it also considers the most sensitive populations identified in the available literature, and importantly, these are the values used in our risk assessments (see “ A Review of the Reference Dose and Reference Concentration Processes,” U.S. EPA, Risk Assessment Forum, Washington, DC, EPA/630/P

- 02/002F, 2002,

a vailable online at http://www.epa.gov/raf/publications/pdfs/rfd

- final.pdf ) . For further discussion of the parameters considered as part of our risk assessment, refer to the final risk assessment docum ent titled “Residual Risk Assessment for the Mineral Wool Production and Wool Fiberglass Manufacturing Source Categories in Support of the June 2015 Final Rule”, which is located in the docket

.

142. Comment: Two commenters (1042

- 0121 and 1042

- 0113) recommended that the EPA conduct the demographic analysis on individuals projected to experience a risk greater than 1

- in

- 1

- million and also on individuals living within five kilometers ( km ) of the facility, regardless of projected risk, consistent with the approach u sed for the Hard and Decorative Chromium Electroplating and Chromium Anodizing Tanks source category. One commenter also suggested analyzing risk as close as a 2 km radius of each facility. One commenter (1042

- 0113) noted that the socio

- economic analysis f or this rule did not evaluate potential disparities within five km for cancer risk at maximum allowable emission levels. The commenter observed that this type of analysis is especially important in instances where a facility is located in a

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minority and lo w

- income community. The commenter asserted that because the EPA only evaluated the risk to the population within a 50

- km radius, the results could be diluted by including populations not in the demographic groups most at risk, especially if the source is l ocated in or next to a minority or low

- income population. Therefore, the commenter recommended an analysis at the five

- km distance be conducted to assess facility impacts to nearby environmental justice communities.

The commenters recommended that the rul e writers work with the EPA Office of Environmental Justice to develop criteria and specific guidance on how to interpret and apply the outcome of the demographics analyses in the rulemaking process.

Response: The commenter is correct that we performed the demographic analyses for the Wool Fiberglass Manufacturing source category differently than we did for the October 2010 proposed RTR for the Hard and Decorative Chromium Electroplating and Chromium Anodizing Tanks source categories. We performed the demog raphic analyses for the se two source categories using two approaches as examples of how such analyses might be developed, and invited public comment on the approaches used and the interpretations made from the results. In the first approach, we focused the analysis on the total populations residing within 5 km of each facility, regardless of their estimated risks, and examined the distributions across various demographic groups within those 5 km circles. That analysis was a “proximity” analysis in that it

c onsidered only the distance from the emission sources to surrounding populations, and not the estimated risks to those populations.

In the second approach, we focused the analysis on the populations within 5 km of any facility estimated to have exposures t o HAP which result in cancer risks of 1

- in

- 1 million or greater or non

- cancer hazard indices of 1 or greater. We examined the distributions of those risks across various demographic groups. In each approach, we compared the percentages of particular demogr aphic groups to the total number of people in those demographic groups nationwide. We stated in the proposed rule for the chrom ium source categories that in future rules we planned to extend the analyses to cover the entire modeled domain for a facility (5 0 km radius) to capture all individuals with risks above 1

- in

- 1 million or greater or non

- cancer hazard indices of 1 or greater. We also stated that generally we have found that using a 5 km radius in the analysis will capture more than 90 percent of the i ndividuals with cancer risks above 1

- in

- 1 million.

In the February 2012 supplemental proposal for the RTR for the chrom ium source categories, our demographic analyses included populations within 50 km of each source (including those very near the sources) with risks of 1

- in

- 1 million or greater or non

- cancer hazard indices of 1 or greater (77 FR 6628, Feb. 8, 2012). We did not include analyses using a 5 km radius in that supplemental proposal nor in the RTR proposal for the Wool Fiberglass Manufacturing sou rce category. We believe that, where a risk assessment has been performed, it is more informative to consider the demographics of all populations (including those beyond 5 km) with elevated risks than to limit the demographics analysis to populations locat ed within 5 km of a facility. Where a risk assessment has been performed, these populations are identified, and the source parameters (like the low release height mentioned by the commenter) are taken into account. As discussed above, we have found that mo st exposure locations with the highest estimated risks are within 5 km of a facility, so extending the radius to 50 km has little impact on an analysis based on risks, but makes more sense because 50 km corresponds to the risk

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modeling radius and includes all populations with elevated risk estimates. We also note that we are working with the Office of Environmental Justice in an ongoing effort to develop new tools for considering environmental justice in rulemakings.

We did not perform a risk

- based demogra phics analysis for the Mineral Wool Production source category because the population of individuals with risks greater than or equal to 1

- in

- 1 million is very small (12,000 individuals) and would not be sufficient to conduct a robust demographic analysis.

143. Comment: Two commenters (1042

- 0121 and 1042

- 0113) opined that the poverty statistics used by the EPA in its demographics analysis to identify low

- income communities should be updated to include 2010 census data, rather than relying on older information, a s number of people in poverty in 2010 is the largest number in the 52 years for which poverty estimates have been published.

Response: The risk

- based demographics analysis for the Wool Fiberglass Manufacturing source category has been updated to use the 20 10 census data. The memorandum “ Risk and Technology Review

— Analysis of Socio

- Economic Factors for Populations Living Near Wool Fiberglass Facilities” dated March 23, 2015 summarizes the results and is available in the docket

.

144. Comment: One commenter (1042

- 0121/1042

- 0299) requested that the EPA provide EJ outreach to affected communities including a plain

- language statement of the health risks and benefits from the rule. The commenter (1042

- 0299) requested that this document include a statement and ana lysis of the supporting cost vs. emission reductions. The commenter (1042

- 0121) requested that this document include the types of harm to public health that the EPA proposes are “acceptable” or “unacceptable.”

Response: A plain

- language statement of the he alth risks and benefits from this rule is provided in the preamble of this rule and more information is available in the docket. For information on supporting cost vs. emission reductions and EJ outreach activities, this information is also available in th e docket. Regardin g the comment that these outrea ch materials should include the types of harm to public health that the EPA proposes are “acceptable” or “unacceptable,” refer to section VI.A of the preamble to the final rule.

145. Comment : One commenter (1042

- 0081/1042

- 0299) opined that the EJ impacts of the wool fiberglass industry warrant stronger standards than proposed by the EPA in 2013 . The commenter cited the socioeconomic analysis for the highest risk area in Kansas City, Kansas, which showed that altho ugh minorities comprise 25 percent of the population, they bear 41 percent of the cancer risk above 1

- in

- 1

- million, and that African Americans comprise 12 percent of the national population compared to 30 percent of the population bearing the highest risk from the facilities in this area.

The commenter added that EPA should consider that the baseline health status of Wyandotte County (which encompasses Kansas City, K ansas ) is lower than the national average according the EPA’s EJ View Health Analysis.

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The commenter also urged the EPA to do more than look at numbers for multiple source categories in a given location and actually use these data in its decision making process and reduce risk and health impacts to local communities beyond what is proposed.

Re sponse: As discussed in our response to comment number 14 2 , where the agency finds risks to be acceptable, the EPA’s obligation under EO 12898 is to ensure that no group is subject to adverse impacts. Where we find those risks to be acceptable no further a ction is warranted.

Regarding the elevated chromium emissions that occurred in Kansas City, the EPA shares the commenters’ concerns about adverse health effects associated with indoor and outdoor air pollution. As further discussed in our response to comm ent number 15 2 , the a gency is committed to making environmental justice a priority. The a gency has worked in the past with the northeast Kansas City, Kansas, neighborhoods on a number of issues, the EPA is committed to continuing the dialogue to help the c ommunity understand the rulemaking process for this rule and future rules, and provide meaningful comment in the process.

Regarding the comment that EPA should consider that the baseline health status of Wyandotte County is lower than the national average, ” w e are not able to determine the baseline health status of individuals or communities in a national rulemaking. Individual privacy issues as they relate to health records and the costs that would be associated with such an analysis make the analysis infe asible. Through the EPA’s interim guidance on EJ and the Action Development Process, the agency is encouraging rule writers and policy makers to look at the whole range of factors that impact communities and population groups when crafting rules. The EPA i s continuing to discuss and pilot approaches that are consistent with the agency’s responsibilities regarding EJ as outlined in EO 12898. In determining the need for tighter residual risk standards, the EPA strives to limit to no higher than 100

- in

- 1 milli on the estimated cancer risk for persons living near a plant if exposed to the maximum pollutant concentration for 70 years and to protect the greatest number of persons to an individual lifetime risk of no higher than 1

- in

- 1 million. Considerations are ma de for all people regardless of racial or socioeconomic status, and the EPA does not believe it is necessary to establish a default factor to account for socioeconomic and other community

- based stressors.

Regarding the risk caused by the Wool Fiberglass Ma nufacturing source category as a whole, we determined that the current health risks posed by emissions from the source category are acceptable , as discussed in refer to section VI.A of the preamble to the final rule ; however, we have taken steps based on o ur AMOS analysis to ensure that these NESHAP reduce the risks posed by this industry. There are approximately 1,200,000 people nationwide that are currently subject to health risks that are non

- negligible (i.e., cancer risks greater than 1

- in

- 1 million) du e to emissions from the Wool Fiberglass Manufacturing source category. We performed an analysis of the demographic makeup of these 1,200,000 people. The demographic distribution of this ‘‘at

risk’’ population is similar to the national distribution of demo graphics for all groups except for the ‘‘minority’’ group (defined as total population minus the white population), which is 16 percent greater than its corresponding national percentage. See the Risk and Technology Review

— Analysis of Socio

- Economic Factor s for Populations Living Near Wool Fiberglass Facilities dated March 23, 2015 in the docket for additional details on the demographic analysis

.

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146. Comment : One commenter (1042

- 0299) advocated for the following additional measures due to environmental justice concerns, to assure compliance and protect the most exposed people:

• Immediate reporting to the public;

• Removal of the freedom of information (FOIA) request process, to allow prompt citizen enforcement of rule violations (including malfunctions);

• Shorter compliance period (than the 1

- year period proposed for wool fiberglass furnaces and the 3

- year period for other sources of pollutants);

• Public distribution of reports detailing each violation;

• Automatic shutoff of the malfunctioning equipment and associated process during the period of corrective action; and

• Measures to ensure a prompt and effective response by facility personnel to malfunctioning equipment.

Response: The EPA has evaluated the appropriate compliance assurance measures and the final rule includes measures that allow effective implementation of the NESHAP requirements, which are designed to protect the health of all populations. The compliance dates were selected considering the shortest amount of time that the affected sources need t o achieve compliance. These requirements include reporting of any emissions exceedance, and requirements to promptly correct malfunctions. Information on exceedances and malfunctions is available to the public through the required reports which are require d in a semiannual basis. Though the pollutants of concern are toxic, their effects are long term, not short term. In situation s where a release can result in an immediate public health effect

, the EPA had developed a separate set of regulations under the authority of CAA section 112(r) that deal with requirement s for immediate public notice. Additionally, t he EPA’s enforcement office or the delegated state, local or tribal office will be inv est igating violation s of the emissions limits established in this rulemaking and will assesses penalties where appropriate. These penalties serve to encourage sources to minimize these exceedances by promptly responding to malfunctions and other types of exce edances.

147. Comment: Three commenters (1042

- 0115a; 0115(d); 0115(f)) stated that it appears that EPA knew about the high levels of hexavalent chromium emitted by CertainTeed in Kansas City, Kansas, but did not inform the community affected by those emissions. The commenters asked the EPA to explain why the community was not informed immediately after CertainTeed testing was conducted.

Response: After the initial tests were conducted, follow up analyses were conducted to verify the accuracy of the results, aft er which community, stakeholders, and industry representatives were informed. EPA Region 7 conducted the monitoring to determine if the emissions pose d health concerns for local residents. When Region 7 informed the public of the ambient air monitors at th e local park, the Certain T eed facility in Kansas City idled ( stopped production but did not shut down) the K2 high emitting furnace

.

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148. Comment: Four commenters (1042

- 0299; 1042

- 0300; 1042

- 0115f; and 1042

- 0115k) expressed concern that the air monitoring c onducted in Kansas City by EPA Region 7 was inadequate. Two commenters (1042

- 0115f and 1042

- 0299) requested that the EPA extend the monitoring program in Garland Park. One commenter (1042

- 0115f) urged the EPA to extend the monitoring program to at least si x months after CertainTeed's K2 furnace returns to service, as a matter of fairness and considering that the risk falls disproportionately on minorities and people who are economically disadvantaged. One commenter (1042

- 0299) requested the EPA to
restart t he monitoring program in this area for at least a year to inform compliance and ensure the rule’s effectiveness at reducing chromium emissions. One commenter (1042

- 0115f) pointed out that the six months of monitoring at Garland Park planned following the 2 011 proposal was not sufficient because it would capture no emissions at all from the K2 furnace because the furnace was shut down due to unfavorable economic conditions, and thus the testing would greatly underestimate the risk that would occur when K2 st arts up again. Another commenter (1042

- 0115k) added that the EPA has gone through a lot of expense to install the air monitoring equipment in Garland Park. The commenter questioned whether there is adequate, ongoing monitoring of pollutants coming from th e Fairfax industrial plants. The commenter also stated that the a gency should conduct air quality monitoring similar to that done in Garland Park (just south of CertainTeed’s K2 plant) each time it proposes RTR rules.

Response : We continue to believe that the risk modeling performed as part of the residual risk assessment is sufficient to determine the risks to potentially exposed populations. These risk assessments give a better long

- term analysis of the risks as opposed to ambient modeling which would be a short

- term snapshot of ambient levels of HAP. As a result, performing monitoring each time EPA proposed an RTR would simply result in a huge expenditure of resources for no real benefit. The other comments specifically relating to Kansas City are beyond the scope of this rulemaking

.

149. Comment: One commenter (1042

- 0115k) requested clarification as to whether the testing conducted by CertainTeed in November 2011 was of the same merit as the testing conducted in September 2011 and whether the EPA considered b oth tests valid. The commenter also asked if the furnace allegedly retired by CertainTeed for 2013 was still in place at the facility, and if so, why? Further, the commenter asked what the penalties will be for not meeting the established standards when th ey are promulgated.

Response: Regarding the quality of the testing, EPA Region 7 conducted the monitoring to determine if the emissions in Garland Park posed health concerns for local residents. After the initial tests were conducted, follow up analyses w ere conducted to verify the accuracy of the results, after which community, stakeholders, and industry representatives were informed. CertainTeed provided actual production data for both K1 and K2 furnaces located at its Kansas City, K ansas facility, as we ll as emissions testing data for the K2 furnace and from its collection and cooling processes on bonded lines. We have not made a comparison between these production data and the Region 7 monitoring data, which was initiated in December 2007. This is becau se the monitoring conducted by Region 7 was not for purposes of the risk and technology review for the Wool Fiberglass Manufacturing NESHAP.

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Regarding the status of the K2 furnace, that furnace was idled for several years before the company shut it down. C ertainTeed is in the process of rebuilding the K2 furnace. The rebuilt furnace has not at this writing been permitted.

Regarding the penalties for not meeting the established standards, establishment of such penalties is outside of the scope of this rulem aking

.

150. Comment: One commenter (1042

- 0075/1042

- 0117) asked if the EPA had collected data on CertainTeed’s production rates during the months preceding the December (2011) monitoring at John Garland Park. According to the commenter, such data would be used to determine if a comparison can be made between production rates and the monitoring and sampling data.

Response: The EPA did not collect production rate data over the December 2011 monitoring period.

151. Comment: There were several comments related to issues involving the local community in Kansas City, Kansas where two wool fiberglass manufacturing facilities are located. These local community issues have been consolidated and grouped under this comment; the following paragraphs summarize specific issues raised by the com menters:

1. One commenter (1042

- 0115a) stated that over 70 percent of African Americans live in counties in violation of the federal air pollution standards and that in every one of the 44 major metropolitan areas in the U.S., African Americans are more likel y than whites to be exposed to a higher level of air toxic contamination. The commenter theorized that as a result of air toxics concentrations within predominantly African American communities, African Americans are nearly three times as likely to be hosp italized or killed. The commenter stated that emissions of air pollutants include lead, which has been tied to educational and behavioral challenges thereby impacting the learning opportunities for children of color and potentially contributing to the ‘sch ool

- to

- prison’ pipe line. The commenter added that air pollutants include mercury, which has been tied to negative birth outcomes in African American families already suffering from high rates of low birth weight and infant mortality.

The commenter added that the presence of toxic facilities in the Kansas City, Kansas communities have negative effects on property values, thereby negatively impacting the economic well

- being and wealth development potential within the communities of color which disproportion ately host facilities that emit pollution. The commenter stated that multiple policy initiatives have been introduced in Congress to defund, that is, to lessen the power of the CAA as well as to significantly reduce the authority of the EPA , which is taske d with monitoring and regulating pollution and other harms in the air that we breathe, the water we drink and the land on which we live.

The commenter noted its support for the CAA as a critical bedrock policy for the protection of the environment and the human health and well

- being and stated that the NAACP will put the power and resources of the association's unit and members behind protecting and defending environmental policies designed to provide

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safeguards to assure that all communities are breathing clean air, ingesting clean water and living and thriving on safe lands.

2. One commenter (1042

- 0115b) stated that as a provider of medical services in the neighborhood, she is very interested in the health of our community. The commenter asked the EPA to prov ide strong oversight on emissions from all manufacturing in the commenter’s geographic area. The commenter stated that history shows that lack of strong oversight often reflects harm to those who reside nearby when toxic chemicals are released without trea tment.

3. One commenter (1042

- 01115c) described the air quality in the Kansas City, Kansas area as terrible and the cause of various health problems, including respiratory and pulmonary effects. The commenter further stated that she was having problems with h er oxygen. The commenter stated that she wants EPA to take corrective action in the Kansas City, Kansas area to lower emissions of air toxics and other pollutants contributing to adverse health effects so people living in her neighborhood can have the same opportunity as anybody else.

4. One commenter (1042

- 0115d) stated that when the Kansas Health Institute in 2009 ranked the 105 counties of Kansas as related to their health, Wyandotte County was ranked 105th, the last of all the counties, the lowest

- rated co unty in the State of Kansas. The commenter observed that physical environment was listed as one of the poor health determents. Quoting from the report, the commenter stated that the physical environment determines the daily condition in which we live, thes e conditions, the quality of air we breathe and the water we drink among them, significantly affect our health. The commenter stated he has lived in the northeast area of Kansas City, Kansas for 63 years and he sees the smoke that comes from many of the pl ants in the Fairfax area of Kansas City, and he wonders how this is affecting his health and the health of the children in the area. The commenter stressed that the agency should set stronger standards that take into account the vulnerability of children. The commenter stated that the citizens who live closest to Fairfax are probably the most vulnerable persons in Wyandotte County. The commenter added that he must depend on agencies like the EPA to provide the proper controls to see that the residents of Fa irfax receive the best protection.

The commenter added that the air quality of the Fairfax district fluctuates and that some days are worse than others in terms of health impacts associated with that air quality. The commenter requested some type of mask b e made available to citizens for days during which poor air quality is present for persons with special pulmonary and/or respiratory needs due to poor air quality.

The commenter continued that it is important for the EPA to learn about the communities which may be more affected by air and water pollution. The commenter added that communication between EPA and the local community should be improved to form a dialogue (between EPA and the community) instead of only a monologue from EPA without opportunity for feedback.

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The commenter was concerned about the toxicity of a local lake and whether it was safe to eat the fish from that lake. The commenter continued that alth ough testing of the waters is now going on, subsistence fishing is practiced in the community and the community has queried EPA for a determination on whether or not it was safe for persons to consume fish from the lake based on their reports, but the EPA has not provided a definitive answer as to whether or not it is safe to eat the fish.

5. One commenter (1042

- 0115e) stated that John Garland Park was a local ‘dump’ that was later repurposed as a landfill, permitted by EPA to be sited in the Quindaro townshi p, a predominantly minority and low

- income community. The commenter recalled that the EPA established the landfill and the clay cap for later use as a playground or low

- income housing project because it was eventually deemed reasonably safe for residential use. The commenter also stated that as a longtime resident of Kansas City, Kansas in the vicinity of John Garland Park, she has experienced air pollution continually released from the John Garland Park landfill, and believes the landfill emissions are neg atively affecting the health of persons in the community. The commenter asserted that it is unfair for the U.S. Government to work against the health and welfare of low

- income people. The commenter added that she does not have much faith in government bec ause government work is counter

- productive to the good will of people who are less well off than others.

6. One commenter (1042

- 0115f) recommended that the EPA should minimize the use of surrogates in all related industries.

7. The commenter (1042

- 0115f) state d that EPA needs to confirm whether and when the wool fiberglass facilities in Kansas City, Kansas (Owens Corning and CertainTeed) ceased using formaldehyde in their binder ingredients, and determine if this is a permanent change. The commenter added that this is important because of the concentration of facilities in Kansas City, Kansas and the fact that formaldehyde is one of the risk drivers.

8. The commenter 1042

- 0115g stated that she works with North East KCK Healthy Kids developing projects that increas e physical fitness and decrease factors of childhood obesity. The commenter explained the relationship between physical activity, increased inhalation depth and frequency and reduction in childhood obesity. The commenter also attended three

- day EPA trainin g on “interior combatants”, which she described as what is dangerous in the home. The commenter explained that increased inhalation during physical activity exposes young people and children to additional risk from inhalation of toxic pollutants, including PM, formaldehyde and hexavalent chromium from wool fiberglass manufacturing and pollutants from many other industries in the area. The commenter is personally aware of children in the community that have started to develop different types of diseases: ast hma, diabetes, childhood obesity, among others. The commenter suggested plant closings, an enclosed playground or similar activity center that could allow children to participate in prolonged and strenuous physical activity without the added inhalation ris k from air toxics.

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9. One commenter (1042

- 0115h) stated that when former president Bill Clinton signed the Executive Order for Environmental Justice, the commenter was led to believe that this was a great moment in time, but it now seems that the Environment al Justice Executive Order is without a spine. The commenter asserted that there were no regulatory tools or teeth or mandates to be enforce reductions in pollution. The commenter observed only industry

- friendly provisions of the Executive Order for Enviro nmental Justice are exercised. The commenter observed huge environmental inequities remain in the area. The commenter noted examples including the toxic waste sites in the northeast area of Wyandotte County, and stated that many people are becoming sick wi th asthma, respiratory cancers, and pancreatic cancer from the exposures to air toxics and other pollution. The commenter added that others are turning to drugs such as crack cocaine because it helps users to breathe and acts as an antidepressant.

Two comm enters (1041

- 076; 1042

- 0115h) opined that the EPA should put in place a more effective and efficient method of communicating with the affected communities in order to ensure excellence in the exchange of relevant, meaningful and timely information. One com menter (1042

- 0115h) requested that the EPA take the following steps to make information available for the population of the Fairfax area of Kansas City, Kansas:

• make information available online and in other formats so that active community members are abl e to disburse that amongst the community;

• make relevant information available in a user friendly context online and in a format that is easily understood by the general public (i.e., the non

- technical reader);

• provide plain language community outreach tool s;

• provide contact phone numbers and email addresses to get additional information.

10. One commenter (1042

- 0115i) stated that he served on the committee to help refurbish John Garland Park, which is a landfill in this area. The commenter observed that it

see ms like a cloud of toxic smoke is coming out of the area, and added that on a clear day, it is easily seen. The commenter added that several studies on the John Garland Park project have been undertaken but no real risk assessment of the landfill has been done. The commenter added that many individuals experienced pulmonary health effects and have died from unknown causes. The commenter stated that this (residual risk) assessment should have been done a long time ago and added that it still seems like ther e are health impacts to residents from the poor air quality of the Fairfax district.

The commenter stated that a relative living in the Fairfax district wears a paper air mask to alleviate breathing problems caused by the poor air quality, and added that the two fiberglass plants and the medical waste incinerator are releasing emissions to the air, and contributing to the area’s air toxics. The commenter stated that from his front porch he has a perfect view of downtown Kansas City, Missouri and a perfect

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view of the Fairfax industrial area and visually observes emissions from these sources as they are released into the ambient air.

11. One c ommenter (1042

- 0115k) stated that she is the President of the Oak Grove Neighborhood Association. The commenter noted th at the Oak Grove Neighborhood is the most northeast situated neighborhood in Wyandotte County. The commenter noted that this is the area impacted by the John Garland Park, the Fairfax industrial complex, coal

- fired plants, the medical waste incinerator and the two wool fiberglass manufacturing facilities. The commenter added that she is speaking on behalf of her neighborhood on the subject of environmental justice. The commenter asked EPA to relay pertinent information in a more timely manner to the communi ty so that residents have an opportunity to get educated about the subject matter and can have meaningful participation. Specifically, the commenter asked that Region 7 take an opportunity to make all information available to the community; notify resident s of information in the local paper, put it on the internet, and give all interested persons the opportunity to understand the risk assessment and impacts to the local area.

The commenter added that despite the fact that hexavalent chromium is a carcinoge n she doesn’t know anyone who would say let’s shut down Fairfax, let’s shut down Owens Corning, let’s shut down everything, because everyone needs jobs and opportunities. However, the commenter added that she would be a proponent or advocate to shut down t he industries if they cannot, and will not, produce their goods and services in a clean and environmentally conscientious manner.

The commenter added that the EPA has the muscle to be able to monitor and enforce rules and regulations. The commenter observ ed that the industry would itself have on

site, and as part of their payroll, the chemists and scientists and whatever else is needed in order to produce a safe product, and that they should have on site anyone and everyone that is need ed to ensure the hex avalent chromium from their manufacturing process does not escape and cause possible harm.

The commenter (1042

- 0115k) asked if the CertainTeed furnace allegedly retired by CertainTeed for 2013 was still in place, and if so, what is the cost effectiveness o f that? What are we looking to determine, to gain from that?

The commenter asked the EPA to do the following:

• to hold a meeting as soon as possible to review the technicalities in this new rule;

• give people an opportunity to give considerable thought and logical input;

• address specific questions including:

- Does EPA know and ensure that this wool fiberglass industry in Fairfax has a process for which to identify and report all the pollutant being emitted?

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- Does EPA have in place something to determine how long the hexavalent chromium was emitted prior to being reported in November of 2010? And if not, then why?

- Does EPA have a method of knowing if the hexavalent chromium has been found in here, by, near

– by any soils or water samples?

- Does EPA know at what point in time the production process emits the most pollutants?

- Does EPA know the short and long

- term risks of the pollutants on our children and adults and the elderly?

- Does the EPA have an obligation to indirectly use its influence to correct environmental justice inequities?

12. A nother commenter (1042

- 0115k) raised the issue of other sources of air toxics and particulate matter, sulfur dioxide and nitrogen oxides the coal

- fired plant that a re added with the hexavalent chromium, the methane coming from the John Garland Park and whatever is emitted from the medical waste incinerator that are mixing in the air.

13. The commenter (1042

- 0115k) wanted EPA to consider whether or not the Oak Grove

comm unity and the northeast area neighborhoods, which are predominantly minority communities, have really been the subject over time of environmental injustice. The commenter explained that environment injustice is one component of a system of external forces, including laws, rules and regulations that have been in place since there was slavery in the U.S. The commenter further stated that when people who looked like her were denied certain opportunities, education opportunities, housing opportunities and so fo rth and so on. The commenter continued that during the '50s and in the '60s and in the '70s there was an ushering in of all kinds of rules and new laws purported to correct the errors of slavery, but these laws and rules and regulations not necessarily did the right thing, and acted not to improve, but to keep the same level of low income, the same level of low attainment and the same level of low quality of life. It is the commenter’s opinion that, as a result, there has been no improvement in the Oak Grov e community from 1995 until now. The commenter accessed a website with information regarding the Federal Interagency Working on Environmental Justice, which includes not only the EPA, but also HUD, the Department of Labor, the Department of Energy, and th e Department of Transportation. The commenter added that all Federal Agencies are supposed to address environmental justice in their rules and regulations to make sure that communities don't turn into communities like hers; and specify corrective action

un der which communities like hers can be improved under the Environmental Justice rules and regulations. To that end, the commenter requested the EPA to use its influence to improve and correct environmental injustice issues in the Oak Grove and the Northeas t neighborhood communities. Specifically, the commenter asked the EPA to secure funding and other resources needed to educate the community and improve the lives of residents through communication, an information exchange and a virtual

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call center. The com menter also suggested the following supplemental environmental projects (SEP) projects:

• A tilapia fishery;

• Investment in the Parkwood Learn to Earn, for youth ages 12 to 14;

• A youth camp; and

• A curb and sidewalk program to train youth and adults how to construct and pour sidewalks and curbs

Response: The EPA shares the commenters’ concerns about adverse health effects associated with indoor and outdoor air pollution. The a gency is committed to making environmental justice a priority. The a gency has wor ked in the past with the northeast Kansas City, Kansas, neighborhoods on a number of issues, some of which have been raised in comments on this proposed rule. The EPA is committed to continuing the dialogue to help the community understand the rulemaking p rocess for this rule and future rules, and provide meaningful comment in the process. The final rule requirements are based on all data collected during the project and those requirements apply to all major sources located in the U.S.

We agree that is crit ically important to provide sufficient information so that affected communities have a meaningful opportunity to participate in EPA rulemakings. In order to disseminate information to the public the agency works with state and local agencies, regional offi ces and community

- based partners. Additionally, the agency continues to think of and pilot new ways to disseminate information to the public.

The Wool Fiberglass rulemaking seeks to minimize adverse health effects by decreasing emissions associated the haz ardous air pollutants emitted from this industry. Furthermore, the EPA has met with various community stakeholders to listen to their environmental justice and other concerns and is involved in an ongoing process with these stakeholders. The issues raised in these comments address source categories that are outside the scope of this rulemaking. However, meetings with stakeholders and the development of actions to address the community’s environmental justice concerns are ongoing as part of the local communi ty stakeholder process.

As explained in the preamble to the final rule, we are promulgating requirements under CAA section 112(f)(2) for the Wool Fiberglass Manufacturing source category. These standards will result in reductions of chromium compound emiss ions , compared to the 2010 baseline estimates . We are also promulgating standards for formaldehyde, methanol and phenol because the 1999 standard was based on an illegal MACT floor calculation as well as served an illegal surrogate . We will address reducti ons in formaldehyde, phenol, and methanol emissions from RS lines in a separate rulemaking

. Detailed documentation of the analysis can be found in: Cost Impacts of the Revised NESHAP for the Wool Fiberglass Manufacturing Source Category (see docket EPA

- HQ

- OAR

- 2010

- 1042). Further, we have determined that the current health risks posed to anyone b y emissions from this source category are acceptable. Because there are about 1,20 0 ,000 people nationwide that are currently subject to health risks which are non

- negligible (i.e., cancer risks greater than 1

- in

- 1 million) due to emissions from this source category, we have performed an analysis of the demographic makeup of these 1,20 0 ,000 people. See section

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VIII.F of the preamble to the final rule and the Risk and Technology Review

– Analysis of Socio

- Economic Factors for Populations Living near Wool Fibe rglass Facilities (dated March 23, 2015) in the docket for additional details on the demographic analysis.

152. Comment: One commenter (1042

- 0115f) added that it is critical that the EPA follow through on their intention to regulate area sources in this category because the elimination of formaldehyde emissions may allow a plant to become technically a minor source while still posing a serious risk from highly dangerous pollutants like hexavalent chromium. The commenter also urged the EPA to set the strongest chromium limits and to set robust limits on all other toxic air pollutants to insure that the Kansas City community recei ves the required ample level of health protection. One commenter (1042

- 0121) strongly supported the EPA’s announcement of plans to regulate wool fiberglass area sources in a future action. According to the commenter, the EPA appropriately recognizes that l ocal communities near wool fiberglass facilities need protection from high chromium emissions, and urged the EPA to promulgate requirements that should also ensure full protection for the most exposed people near these facilities from all HAP and other hig h risks, including acute health risk. The commenter urged the EPA to propose this rule as soon as possible during 2012, without delay.

Response: Regarding the comments on area sources, the EPA is finalizing standards for area sources. Regarding the comment on chromium limits, the EPA is finalizing chromium standard for this source category to provide an ample margin of safety, as discussed in the preamble to the final action.

153. Comment: One commenter (1041

- 0 0 76) stated that, because the EPA (along with othe r federal agencies) is charged with affecting environmental justice for all and because an ecological balance is a desired outcome of a sustainable community, the EPA should exercise due diligence in strongly encouraging and promoting resource partnerships (along the lines of SEPs (Supplemental Environmental Projects)) that will significantly accelerate the rate at which the affected community sustainably heals f rom the wounds inflicted by HAP producing decisions and processes.

Response: The agency agrees w ith the commenter and supports partnerships across multiple stakeholders. In the case of this specific rule, the EPA regional offices, in particular Region 7 has provided technical support as a means to assist collaboration between community

based organiza tions and governmental entities. Additionally, the agency also recommends that public work with their regional EPA office and local and state departments of health and environmental quality to devise a community involvement strategy to address local air po llution health issues.

154. Comment: One c ommenter (1041

- 0080/1042

- 0120) stated that while the EPA reasonably interprets the term “public health” as used in CAA section 112(f) to include consideration not only of potential impacts to the population as a whole, but also to sensitive subpopulations, those populations should be identified according to their particular health

- based sensitivities (e.g., asthmatics) rather than demographic classifications unrelated to particular health

- based sensitivities (e.g., popul ation without a high school diploma). In the commenter’s opinion, injecting “environmental justice” considerations into CAA section 112(f) standard

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setting would inappropriately cause arbitrary policy and political considerations to trump objective scienti fic analysis and would not be a supportable interpretation of CAA section 112(f).

Two commenters (1041

- 0080/1042

- 0120 and 1042

- 0118) asserted that the EPA does not have authority to consider demographics in conducting residual risk assessments. The
comment ers stated that it would not be reasonable to construe the term “public health” as used in CAA section 112(f) as allowing consideration of demographic classifications that bear no relationship to the potential health effects presented by the HAP at issue f or the given source category or subcategory. The commenters added that the EPA’s proposal would unreasonably inject racial, ethnic, and other policy considerations into a program designed to provide protection for the public at large, thus inappropriately causing arbitrary policy and political considerations to trump objective scientific analysis.

Response: Through the EPA’s interim guidance on Environmental Justice and the Action Development Process, the agency is encouraging rule writers and policy makers to look at the whole range of factors that impact communities and population groups when crafting rules. The EPA is continuing to discuss and pilot approaches that are consistent with the agency’s responsibilities regarding environmental justice as outlin ed in EO 12898. In determining the need for tighter residual risk standards, the EPA strives to limit to no higher than 100

- in

- 1 million the estimated cancer risk for persons living near a plant if exposed to the maximum pollutant concentration for 70 year s and to protect the greatest number of persons to an individual lifetime risk of no higher than 1

- in

- 1 million. Considerations are made for all people regardless of racial or socioeconomic status, and the EPA does not believe it is necessary to establish a default factor to account for socioeconomic and other community

- based stressors. The EPA defines “environmental justice” to mean fair treatment and meaningful involvement of all people, and this definition represents a commitment to ensuring that the EPA works to improve conditions affecting the public health of all Americans so that everyone has access to clean water, clean air

, and healthy communities

. As stated in the Benzene NESHAP ((54 FR 38044, 38061, September 14, 1989), in determining the need f or residual risk standards, we strive to limit to no higher than approximately 1

- in

- 10 thousand (100

- in

- 1 million) the estimated cancer risk that a person living near a plant would have if he or she were exposed to the maximum pollutant concentrations for 70 years and, in the AMOS decision, to protect the greatest number of persons possible to an individual lifetime risk level of no higher than approximately 1

- in

- 1 million. These considerations are made for all people, regardless of racial or socioeconomic status. However
, in determining whether to require additional standards under the second step of the Benzene analyses, we are allowed to weigh the cancer risk value with series of other health measures and factors such as control costs and demographic anal yses. This is consistent with the position presented in the Residual Risk Report to Congress where we explained that the Agency typically uses population and demographic data that are based on the census block level in its air toxic exposure assessments. ( p. 42)

. As previously explained, section 112(f)(2) of the CAA expressly preserves our use of the two

- step process for developing standards to address residual risk and interpret “acceptable risk” and “ample margin of safety” as developed in the Benzene NESHAP (54 FR 38044, September 14, 1989). And the U.S. Court of Appeals for the D.C. Circuit has affirmed this approach of implementing CAA section 112(f)(2)(A): NRDC v. EPA , 529 F .3d 1077, 1083 (D.C. Cir. 2008)

.

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As explained at proposal and in various responses to c omments in this document, we conducted a risk

- based demographic analysis for the Wool Fiberglass Manufacturing source category as part of the risk assessment. We determined that the current health risks posed by emissions from the source category are accep table for all population groups. However, because there are about 1.2 million people nationwide that are currently subject to health risks which are

non

- negligible (i.e., cancer risks greater than 1

- in

- 1 million) due to emissions from this source category, we performed an analysis of the demographic makeup of these 1.2 million people. The demographic distribution of this ‘‘at

- risk’’ population is similar to the national distribution of demographics for all groups except for the ‘‘minority’’ group (defined a s total population minus the white population), which is 16 percent greater than its corresponding national percentage. See the document titled “Risk and Technology Review

— Analysis of Socio

- Economic Factors for Populations Living Near Wool Fiberglass Facil ities” dated March 23, 2015 in the docket for additional details on the demographic analysis. In summary, while we analyzed the demographic makeup of the at

- risk populations surrounding the facilities with source categories addressed by this rule making, w e ultimately reaffirm our initial findings that the risks from each source category are acceptable for all population groups and protect public health with an ample margin of safety.

Regarding the comment that the EPA does not have authority to consider de mographics in conducting residual risk assessments, we note that in this rulemaking the risk considerations were made for all people regardless of racial or socioeconomic status. Therefore this comment is moot. However, because there are about 849,000 peop le nationwide that are currently subject to health risks which are non

- negligible (i.e., cancer risks greater than 1

- in

- 1 million) due to emissions from this source category, we performed an analysis of the demographic makeup of these 849,000 people. The d emographic distribution of this ‘‘at

- risk’’ population is similar to the national distribution of demographics for all groups except for the ‘‘minority’’ group (defined as total population minus the white population), which is 11 percent greater than its c orresponding national percentage. See the Risk and Technology Review

— Analysis of Socio

- Economic Factors for Populations Living Near Wool Fiberglass Facilities in the docket for additional details on the demographic analysis. 76 FR 72807. In sum, while we a nalyzed the demographic makeup of the
at

- risk populations surrounding the facilities with source categories addressed by this rule making, we ultimately reaffirm our initial findings that the risks from each source category are acceptable and protect publi c health with an ample margin of safety.

9. Miscellaneous
155. Comment : One commenter (1042

- 0348) requested that the EPA modify those instances in the 2014 proposal where furnace rebuilds are characterized as reconstruction, explaining that fiber glass furnaces ar e “rebuilt,” not “reconstructed,” which has a very specific meaning in 40 C.F.R. section 63.2.

Response: There is only one instance in the 2014 proposal where “reconstruction” was used in place of “rebuild” in the preamble, and there were no instances in t he rule. In the final proposal, the EPA does not confuse these terms.

156. Comment: One commenter (1041

- 0075/1042

- 0117) asked if CertainTeed would be required to utilize the less toxic type of refractory bricks in its glass

- melting furnaces.

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Response: We are no t imposing requirements on the kind of bricks to be used in glass

melting furnaces as part of the final rule. As explained in section VI.B of the preamble to the final rule, we are promulgating a limit of 2.5E

- 04 lb chromium compounds per ton of glass pull ed for both existing and new furnaces. The final rule does not specify the actions owners or operators must take to compl y with this limit.

157. Comment: Two commenters (1042

- 0115j and 1042

- 0120) stated that wool fiberglass industry provides significant enviro nmental benefits and is proud of the public health and environmental benefits realized by the use of fiber glass insulation products. The commenters emphasized that their products save energy and prevent pollution, including GHG, and reduce waste by the in dustry’s reuse of waste materials. One commenter (1042

- 0115j) also noted other benefits of insulation, such as its cost effectiveness in saving energy, comfortable buildings, and health benefits.

One commenter (1042

- 0115j) noted that the wool fiberglass i ndustry is a strong advocate for responsible product stewardship, citing the voluntarily reformulation to non

- PF binders and that the entire industry will have phased out PF binders within the next couple of years. The commenter added that research conducted by the International Agency for Research on Cancer, the National Toxicology Program and the California Office of Environmental Health, has resulted in a determination that wool fiberglass is not a carcinogen.

Response: The a gency acknowledges the comment.

158. Comment: One commenter (1042

- 0108) stated that the government is going to enact a new law that would not allow people 16 and younger to work. According to the commenter, horse owners would be unable to take care of them. The commenter further stated if the government were to pass this law, people could not participate in 4

- H, an organization that works with youths

. As a result, many would have spare time which they would u se in non

productive ways and therefore the government would have created more problems than solutions. The commenter requested that the government please take this into consideration.

Response: This comment is beyond the scope of this rulemaking.

159. Comment : One commenter (1042

- 0115f) requested that the EPA confirm whether the Owens Corning and CertainTeed facilities in Kansas City, Kansas have ceased using PF binders, and if not, when and whether this is a permanent change. The commenter stated that this is important because of the concentration of facilities in Kansas City, Kansas and the fact that formaldehyde is one of the risk drivers.

Response: We are not requiring that any wool fiberglass facilities cease using PF binders. Facilities that use PF bind ers are subject to the major source standards being finalized. Facilities that do not use PF binders are subject to the area source standards being finalized.

160. Comment: One commenter (1042

- 0120) stated that sources in the wool fiberglass source category do not emit COS in response to preamble language (at page 72791) that stated “We are proposing to replace CO as a surrogate for COS with COS emission limits. We are, therefore proposing to add emission limits for COS.” The commenter requested that this text

s hould be deleted.

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Response: We agree and have revised the final rule text accordingly.

161. Comment: One commenter (1042

- 0120) stated that the emissions inventory data the EPA used for modeling risks contained several inaccuracies. Specifically, the commenter stated that several sources are incorrectly described as having FA lines when in fact they have RS lines. According to the commenter some manufacturing lines at the OCIS Eloy, Kansas City, and Santa Clara facilities are described with an SCC code for flame attenuation lines. The commenter suggested that the SCC codes and descriptions should be updated to denote the correct status of the manufacturing lines. The commenter recommended that the EPA should check the coding for all fiber glass facilities for acc uracy. The commenter asked that the EPA also check to be sure that similar misclassifications did not occur with respect to the manufacturing facilities in other analyses performed by the EPA for rulemaking purposes.

Response: We have noted and verified the commenter’s information and made the appropriate changes to the project data base and modeling file.

162. Comment: One commenter (1042

- 0120) formally requested that the EPA provide a second public comment period, which would allo w sufficient time, such as 60 days, to review a revised proposal. As these comments illustrate, the commenter asserted, there are issues that the EPA has yet to resolve as to the legal viability of the 2011 proposed rule and that will impact the ability of the wool fiberglass manufacturers to conduct business. Specifically, the commenter listed the following: (1) the EPA’s collection and consideration of data not available during the public comment period, especially the latest data from the CAA section 114 information request; (2) the EPA’s use of non

- PF emissions data, use of below the minimum detection limit data and use of data from area sources to set the MACT floor; (3) the EPA’s representation that all companies could meet the proposed emission limits , when in reality the majority of fiber glass manufacturers cannot meet, at a minimum, the proposed PM, HF, HCl, formaldehyde, phenol, and methanol limits; (4) improper consideration of the facts surrounding hexavalent chromium emissions due to a rush to i ssue the 2011 proposal; and (5) various other concerns articulated in its comments.

Response: The commenter provided comment during the comment period, provided comment after the close of the comment period, and initiated several meetings with the EPA to discuss the issues mentioned above. We addressed these and other comments in our supplemental proposal on April 15, 2013. Our responses to comments received on the supplemental proposal are included in this document.

163. Comment : One commenter (1042

- 0300/1042

- 0348) opined that the health and environmental benefits of their manufactured product (i.e., use of waste glass as a raw material, cost effectiveness of energy efficiency achieved as a result of insulation use, and pollution prevention achieved through en ergy efficiency) should factor more significantly into EPA’s cost

effectiveness value.

Response : We note that the CAA does not mandate a specific method of cost analysis. However, the factors cited by the commenter are beyond the scope of the types of co st analyses that EPA typically performs to support rulemaking under the CAA. The EPA believes that in order to promote consistency in the types of economic burdens we impose on regulated

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industries, we should use a consistent set of criteria to determine c osts and benefits. In addition, the commenter did not provide data that the EPA could use to include the cited product benefits in our cost analysis

.

C. Issues Related to Area Sources Only

1. EPA Decision and Authority to Regulate Area Sources
164. Comment : One comm enter (1042

- 0120/1042

- 0300/1042

- 0348) contended that, because chromium emissions do not exceed 10 tons per year from any one facility, a MACT standard for chromium is not appropriate for area sources.

Response : The EPA in finalizing a GACT standard for ga s

- fired glass

- melting furnaces located at wool fiberglass manufacturing facilities that are area sources, not a MACT standard. S ection 112(a) of the CAA defines major sources as those that have the potential to emit at least 10 tons of HAP per year or 25 t ons of any combination of HAP per year. The requirement to adopt MACT standards applies to each category or subcategory of major sources of HAP, under CAA section 112(d)(1). For sources below the major source threshold, the EPA has the discretion to require GACT under CAA section 112(d)(5). Only major sources are subject to a MACT standard under 40 CFR part 63, subpart NNN, and area sources producing wool fiberglass are subject to a GACT standard in 40 CFR part 63, subpart NN. Refer to the EPA’s
respo nse to comment number 16 7 for further discussion of the EPA’s decision to establish a GACT standard for chromium emissions from gas

- fired furnaces at area sources.

165. Comment : One commenter (1042

- 0120) noted that the EPA has recognized that the majority of w ool fiber glass manufacturing is no longer subject to the MACT standard, yet the EPA has allowed a single facility’s test results in an oxyfuel furnace showing elevated hexav a lent chrom ium emissions to trigger pulling the entire industry back into the MACT or area source standards. The commenter stated that this decision ignores the significant

– near elimination

– reduction of the only specific HAP regulated under the Wool Fiberglass MACT and would bring all the wool fiber glass facilities back under the M ACT when virtually all facilities’ testing showed very low hex avalent chrom ium emissions.

Response: We disagree with this comment. As explained in our April 2013 proposal and further discussed in section VII.A.3 of the preamble to the final rule , we issue d a CAA section 114 ICR in December 2012 requesting test data on total chromium compounds emissions from all glass

- melting furnaces and we were able to confirm our view of chromium emissions from this source prior to our April 2013 proposal. In our Novembe r 2014 proposal, we also explained that as part of the data collection effort associated with this rulemaking, we collected source test data on 14 furnaces with information on furnace age, last rebricking or repair dates, current furnace age, and anticipat ed or planned future furnace replacement. We also explained that we had obtained repeat testing for three rebuilt gas

- fired glass

- melting furnaces. We further explained that of the 14 tested furnaces, all four furnaces over 12 years old exceeded the
propos ed chromium limit. Of the 10 furnaces under 12 years old, three exceeded the limit (one only marginally), and seven tested in compliance with (i.e., below) the proposed chromium limit. (79 FR 68021). See also 72 FR 22379

- 82 for our discussion of the test d ata the a gency used to support the proposed chromium compounds limit.

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As part of our data gathering exercise, we carefully reviewed each test report conducted for this industry and discussed the results with company operators. We learned that although the Kansas City K2 emitted in 2012 at extremely high levels, when the furnace was less than two years old, chromium emissions measured on the same scale as other newer furnaces in this industry currently measure. We also confirmed that chromium emissions incr ease with furnace age as the refractories age, and that the type of furnace at the high emitter is an emerging new technology that is preferred across the industry where a source of industrial oxygen is economically available.

As explained earlier, we did obtain test data subsequent to the test data that this commenter describes as an “outlier.” We also note that when we conducted our review of this data, we learned that the company operator knew the emissions of chromium compounds were very high, that the source of the chromium was the refractory lining of the furnace, and that the emissions of chromium increased with furnace age. Only the amount of chromium that was in the hexavalent state (93 percent) was new information to the operator. Thus, contrary t o the commenter’s opinion, the EPA’s decision to regulate area sources was not based on the performance of a single facility. Furnace emissions test data were collected from all wool fiberglass manufacturing facilities to determine the scope and extent of the area source emission levels. The data collected for gas

- fired furnaces demonstrate the current and potential future high levels of chromium emitted from multiple gas

- fired glass

- melting furnaces located at wool fiberglass manufacturing facilities that are area sources.
The EPA acknowledged in the 2011 proposal (76 FR 72778) and 2013 proposal (78 FR 22375) the significant effect that binder change has had on reducing HAP emissions from the source category; however, as discussed in section II.B of the pre amble to the 2013 proposal, chromium emissions from furnaces are not affected by the reformulation of the binder (78 FR 22373

- 22374, 22375). Further, as discussed in the preamble to the 2013 proposal (78 FR 22375), the Urban Air Toxics Strategy (Strategy) requires the EPA to ‘‘assure that sources accounting for 90 percent or more of the 30 identified hazardous air pollutants are subject to standards.’’ These are the HAP that pose the greatest potential health threat in urban areas, including chromium
compou nds. It is under this Strategy that the EPA is establishing a chromium standard for area

sources.

2. Decision to Apply GACT to Area Sources
166. Comment : One commenter (1042

- 0299) contended that a GACT limit for area sources is not justified and the EPA should set a MACT standard. The commenter argued that the EPA must establish a MACT standard, not technology review, for area sources because this rulemaking is the first time the EPA is setting standards for chromium for area sources in this source category, and a technology review is a post

- MACT compliance review. The commenter also opined that the EPA is not prohibited from setting MACT standards for area sources, and the EPA has this opportunity to achieve additional public health protection.

The commenter (1042

- 0299) noted that the EPA’s socioeconomic analysis for Wool Fiberglass showed that this source category’s emissions have disproportionate impacts on minorities and people below the poverty level; and that the EPA’s socioeconomic analysis for the high

- risk C ertainTeed facility shows an even more extreme, disproportionate impact of its pollution on minority communities. The commenter argued that, because of the environmental

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justice effects of this rule and the need to protect public health, the EPA should app ly CAA sections 112(d)(2) and (3) instead of CAA section 112(d)(5) to set the area source standards. The commenter maintained that the EPA has full authority under CAA section 112(d)(5) to use the MACT analysis to set these standards, instead of setting st andards based on GACT.

Response: We disagree with the comment. Under CAA section 112(d)(5), the Administrator may, in lieu of standards requiring MACT under CAA section 112(d)(2), elect to promulgate standards or requirements for area sources "which provi de for the use of generally available control technologies or management practices by such sources to reduce emissions of hazardous air pollutants." Section 112 of the CAA gives us discretion in addressing area sources, providing in section (d)(5) an alter native standard for area sources for categories listed pursuant to subsection (c), we may, in lieu of a MACT standard, elect to promulgate GACT standards or management practices by such sources to reduce emissions of HAP. Thus, we are not required to condu ct a MACT analysis for area sources under s ection 112 of the CAA as the commenter has suggested, but have elected to propose and promulgate GACT standards, as is our discretion to do so. As the commenter notes, we did consider what the MACT limits would be in making this election, and rejected that option based on both the cost of the option and the absence of environmental benefits for the cost.

Beginning in 1999, the a gency set MACT standards for the wool fiberglass manufacturing source category. As expl ained in our April 2013 proposal, in the conducting the mandatory RTR for this source category we determined that there were elevated chromium emissions from gas

- fired glass

- melting furnaces. Under existing regulations, major sources become area sources by virtue of eliminating formaldehyde from their processes. There are no differences between gas

- fired glass

- melting furnaces in use at area and major sources. Area sources were largely unregulated until this final action . Our April 2013 contains a lengthy d iscussion on the industry trend for this source category. (78 FR 22374

- 76).

Additionally, we note that while we have no obligation under CAA section 112(f)(2) to evaluate risk for area sources in standards developed under the Urban Air Toxics Strategy, we also included area sources in the risk assessment conducted for this source category to support the 2011, 2013, and 2014 proposals , and therefore, we reviewed the risk from area sources at their current emissions levels. Finally, we are setting the same chromium compound limits for glass

- melting furnaces at area and major sources.

Based on this review, we believe we have achieved both the requirements for an area source rule and protection of public health with the final chromium limits for wool fiberglas s furnaces located at area sources.

3. Glass

- Melting Furnace Emission Limits
167. Comment : One commenter (1042

- 0347) contended that the EPA failed to comply with the Act ( 42 U.S.C. § 7412(d)(1), 7412(d)(5); 42 U.S.C. § 7412(k); Nat’l Lime Ass’n v. EPA

, 233 F.3d 62 6, 633 (D.C. Cir. 2000 ) in not regulating all listed HAP for listed area sources. The commenter supported the EPA’s addition of a chromium limit but expressed concern that the EPA’s removing PM as a surrogate for metal HAP has removed protections from emis sions of

non

- chromium metals (e.g., arsenic, nickel, manganese, lead, selenium, cadmium, cobalt, beryllium, and antimony ) that are not already controlled by the chromium limit. The commenter

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also contended that the EPA has failed to fulfill the requirement to provide a reasonable explanation for not setting a limit on area sources’ emissions of these other metals.

Response: We disagree with the comment. As explained in section VII.A of the preamble to the final rule, under CAA sections 112(c)(3), (d)(5), an d (k)(3), we regulate emissions of the 30 most toxic HAP emitted by area sources. These provisions do not require the EPA to regulate all HAP from all HAP

- emitting processes as we must do when setting MACT standards. For the reasons stated in section III.E of the preamble to the 2014 proposal, the EPA determined that a PM limit is not warranted for area sources. As stated therein,

“setting emission limits for chromium alone achieves the objectives of the Strategy because controls needed to meet the chromium limit will reduce both total PM and its chromium component as the furnace emissions pass through operational PM controls. We also note that for gas

- fired glass

- melting furnaces, chromium and PM reductions are achieved due to the co

- control charact eristics of the existing controls (the DESP). Because owners/ operators must maintain PM controls in order to continue to meet the chromium limits in the rule, PM co

- control benefits are realized from the reduction in chromium compounds.”

The EPA has det ermined that a chromium limit is sufficient for the EPA to achieve its goals under the Urban Air Toxics Strategy (Strategy), which was discussed at length in the 2013 proposal (78 FR 22375

– 22378).

4. Economic Impacts
168. Comment : One commenter (1042

- 0299) conte nded the EPA failed to explain why pound per dollar of reduction is an appropriate metric of cost effectiveness because it does not assess the value of health protection including reductions in cancer incidence and non

- cancer risks, toxicity and health haz ards reduced for children’s health and early life exposures, and environmental justice considerations. The commenter argued that the EPA must consider how much emission reduction is needed to reduce the high cancer risk numbers and protect public health, a s required by the CAA.

Response: Regarding the commenter’s assertion that our cost effectiveness measure is unreasonable, we disagree as explained in the response to comment number 13 7 . Section 112(d) of the CAA neither specifies nor mandates a cost methodology. In Husqvrna AB v. EPA, 254 F.3d 195, 200 D.C. Cir. 2001), the D.C. Circuit found EPA’s chosen methodology “reasonable” because the statute “did not mandate a specific method of cost analysis.”

Regarding t he comment that the EPA must consider how much emission reduction is needed to reduce the high cancer risk numbers and protect public health, as we explained in the Benzene NESHAP, in determining the need for residual risk standards, we strive to limit to no higher than approximately 1

- in

- 10 thousand (100

- in

- 1 million) the estimated cancer risk that a person living near a plant would have if he or she were exposed to the maximum pollutant concentrations for 70 years and, in the AMOS decision, to protect the greatest number of persons possible to an individual lifetime risk level of no higher than approximately 1

- in

- 1 million. These considerations are made for all people regardless of racial or socioeconomic status.

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However, in determining whether to require additional standards under CAA section 112(f), these levels are not considered rigid lines, and we weigh the cancer risk values with a series of other health measures and factors in both the decision regarding risk acceptability and in the AMOS determinat ion. We also consider cost of controls in the AMOS determination. While we analyzed the demographic makeup of the at

- risk populations surrounding the facilities within the source category addressed by this rule making, we ultimately concluded that the risk s were acceptable for all population groups and that they would protect public health with an ample margin of safety.

Regarding the risk caused by the Wool Fiberglass Manufacturing source category as a whole, we determined that the current health risks pos ed by emissions from the source category are acceptable (79 FR 68020) ; however, we have taken steps based on our AMOS analysis to ensure that these NESHAP reduce the risks posed by this industry. There are about 1,200,000 people nationwide that are current ly subject to health risks that are non

- negligible (i.e., cancer risks greater than 1

- in

- 1 million) due to emissions from the Wool Fiberglass Manufacturing source category. We performed an analysis of the demographic makeup of these 1,200,000 people. The d emographic distribution of this ‘‘at

- risk’’ population is similar to the national distribution of demographics for all groups except for the ‘‘minority’’ group (defined as total population minus the white population), which is 16 percent greater than its c orresponding national percentage. See the Risk and Technology Review

— Analysis of Socio

- Economic Factors for Populations Living Near Wool Fiberglass Facilities dated March 23, 2015 in the docket for additional details on the demographic analysis.

169. Comment : O ne commenter (1042

- 0300/1042

- 0348) indicated that facilities will need to install control equipment to achieve the chromium standard for area sources and that the EPA has grossly underestimated the cost of this equipment for area sources in both the 2013
p roposal (78 FR 22370, April 15, 2013) and 2014 proposal (79 FR 68011, November 13, 2014). The commenter provided cost

- effectiveness estimates (in dollars per pound of chromium emission reduction) developed by Trinity Consultants for various technologies: H EPA filter would be $18,500 to $24,100; venturi scrubber would be $29,700 to 41,700; 3

- stage filter after dry ESP would be $49,100 to $63,900.

Response : In response to comments such as this one, the EPA has amended the proposed chromium limit for gas

- fire d glass

- melting furnaces at major sources and is establishing a limit of 2.5E

- 04 pounds chromium per ton of glass pulled in the final rule. Section VII.A of t he preamble to the final rule also contains the discussion on the cost considerations based on

co mments the a gency received on the November 2014 proposal. Based on emissions data submitted in 2010 and 2012 by all area source wool fiberglass manufacturers on every furnace type, the EPA believes that all area source furnaces currently meet this chromium limit. Therefore, we disagree with the commenter that area source facilities will need to install control equipment to comply with subpart NN. As also previously explained, we found $11,000 per pound chromium removed to be a reasonable cost in the final C hromium Electroplating RTR rulemaking, where we regulated chromium compounds (77 FR 59220, September 19, 2012). Thus, contrary to the commenter’s assertion the cost

- effectiveness for this rule is not in excess of the cost effectiveness values the EPA has found acceptable in prior CAA section 112 cost effectiveness analyses. Moreover, CAA section 112(d) neither specifies nor mandates a cost methodology. In Husqvrna AB v. EPA, 254 F.3d 195, 200 D.C. Cir. 2001), the D.C. Circuit

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found the EPA’s chosen methodo logy “reasonable” because the statute “did not mandate a specific method of cost analysis.” We consider these costs reasonable because chromium is a toxic HAP.

5. Miscellaneous
170. Comment : One commenter (1042

- 0299) opined that the EPA has not shown that it has m et the 90 percent requirement for chromium under the Urban Air Toxics Strategy (Strategy). The commenter asserted that the EPA has full authority to regulate wool fiberglass area sources for chromium emissions and should do so.

Response: The EPA has docume nted in the following memorandum that is has achieved the 90 percent reduction of chromium emissions required by the Strategy: memorandum “Technical Memorandum

- Emission Standards for Meeting the 90 Percent Requirement under Section 112(c)(3) and Section 112(k)(3)(B) of the Clean Air Act” (February 18, 2011 )(EPA

HQ

- OAR

- 2010

- 1042

- 0262), the EPA. The EPA also indicated in the preamble to the 2013 proposal (78 FR 22375, April 15, 2013) that it had achieved the 90 percent target. Further, we agree with the co mmenter that the EPA has full authority to regulate wool fiberglass area sources for chromium emissions because nothing prevents us from going beyond the minimum 90 percent and subjecting more categories of area sources to regulation under this program, an d we are doing so in the final rule.

171. Comment : One commenter (1042

- 0299) opined that the EPA is not allowed under the CAA sections 112(d)(5) and (6) to consider cost

- effectiveness of the rule as part of its analyses and conclusions on technology review, AMOS, and GACT, especially for wool fiberglass because CAA section 112(d)(5) already includes the consideration of “economic impacts.” The commenter a rgued that this reading of the CAA is supported by a Senate Report (S. REP. NO. 101

- 228, at 144 (1989)), which states that “generally available” includes “methods, practices and techniques which are commercially available and appropriate for application by the sources in the category considering economic impacts and the technical capabilities of the firms to operate and maintain the emissions control systems.”

The commenter further argues that, even if the EPA could use cost

- effectiveness to set standards , it has failed to justify such weak levels given that the EPA’s selection of acceptable
cost

- effectiveness is arbitrary, especially considering that the costs represent such a small fraction of the wool fiberglass industry’s profits.

Response: The EPA dis agrees that the Senate Report cited by the commenter means that the EPA cannot consider cost in establishing GACT. This Senate Report describes GACT as standards or requirements reflecting application of generally available control technology or management practices, that is, “methods, practices and techniques which are commercially available and appropriate for application by the sources in the category considering economic impacts and the technical capabilities of the firms to operate and maintain the emi ssions control systems” (Senate Report Number 101

- 228, December 20, 1989). Consistent with the legislative history, in addition to considering technical capabilities of the facilities and the availability of control measures, we may consider costs and eco nomic impacts in determining GACT, which is particularly important when developing regulations for source categories that may have few establishments and many small businesses, or when determining whether additional control is

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necessary for sources with em issions that are already well controlled as a result of other existing or applicable standards.

As also explained in our November 2011 proposal, the EPA may consider costs in its decision to set standards under the ample margin of safety step of CAA sect ion 112(f)(2). This is consistent with the approach set out in the Benzene NESHAP framework for assessing acceptable risk and ample margin of safety. As previously explained, s ection 112(f)(2) of the CAA expressly preserves our use of the two

- step process for developing standards to address residual risk and interpret “acceptable risk” and “ample margin of safety” as developed in the Benzene NESHAP (54 FR 38044, September 14, 1989). We also note that the U.S. Court of Appeals for the D.C. Circuit has affirm ed this approach of implementing CAA section 112(f)(2)(A): NRDC v. EPA , 529 F.3d 1077, 1083 (D.C. Cir. 2008). We also believe that the EPA may consider cost in revising emissions standards under CAA section 112(d)(6). ( Ass'n of Battery Recyclers v. EPA , 716 F.3d 667, 673 (D.C. Cir. 2013)

. We evaluated the costs of the chromium compounds limits and presented our analy ses in the various proposals. As explained earlier, section VII.A of the preamble to the final rule also contains detailed discussions of the cost considerations based on comments the a gency received on the November 2014 proposal. Refer to our AMOS analysi s memorandum for a discussion of the other options we considered, the cost impacts of those options, and the associated risk results, which is available in the docket to this rule.

172. Comment: One commenter (1042

- 0299) contended that the EPA must consider public health in setting area source standards under CAA sections 112(c)(3) and (k), as follows : (1) whether the rule achieves (or contributes to) achievement of “a substantial reduction in emissions of HAP from area sources,” which is a key purpose of th e area source program 42 U.S.C. § 7412(k)(1); (2) what potential reductions in cancer and non

- cancer risks are associated with lower emissions, and does the rule achieve or contribute to the achievement of the reduction of cancer incidence by 75 percent, w hich is a major purpose of the area source program? 42 U.S.C. § 7412(k)(1); (3) use the best available science in considering health hazards crea ted by the specific emitted HAP and the National Academy of Sciences recommendations toxicity (including childr en’s health and early

- life exposure); and (4) follow EPA’s environmental justice plan (Draft Technical Guidance for Assessing Environmental Justice in Regulatory Analysis (May 1, 2013); EJ Plan 2014, http://www.epa.gov/environmentaljustice/plan

- ej/).

Respo nse: We disagree with the comment. The a gency listed gas

- fired glass

- melting furnaces at areas sources and proposed emissions standards for some of the 30 urban HAP, under CAA sections 112(c)(3), (d)(5), and (k)(3). (78 FR 22376).

Section 112 of the CAA c ontains several provisions that authorize the a gency to regulate

area sources. As explained in our April 2013 proposal, CAA section s 112(c)(3) and (k) require the EPA to identify and list the area source categories that represent 90 percent of the emission s of the 30 urban air toxics associated with area sources and then set standards for them under CAA section 112(d). We also explained that CAA section 112(k)(3), which cross

- references CAA section 112(c)(3), requires the EPA to identify a list of at least 30 air toxics that pose the greatest potential health threat in urban areas (the “urban” HAP). This is considered the Urban Air Toxics Strategy. ( CAA Section 112(k)(3)(B)(i) and (ii); 64 FR 38706 (July 19, 1999)).

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We acknowledge that CAA section 112(c) also authorizes the agency to list area sources pursuant to a finding of a threat of adverse health effect.

Additionally, as previously explained, while we have no obligation under CAA section 112(f)(2) to evaluate risk for area sources in standards developed under the Urban Air Toxics Strategy, we also included area sources in the risk assessment conducted for this source category

. All wool fiberglass facilities were major sources at the time of the MACT standard and all facilities are incl uded in the source category

.

173. Comment : One commenter (1042

- 0299) contended that the EPA must do the following in setting area source standards: (1) collect and consider the starting point or baseline “overall health” status of the affected individuals and communities as part of its Environmental Justice (EJ) analysis; (2) include in its EJ analysis an assessment of the percent of the population with limited English proficiency, infant mortality, and low birth

- weight births; (3) analyze those who are the mos t exposed, within 3 miles of existing plants; for urban areas like Kansas City; and (4) assess the demographics within 1 mile of each plant; and use the most recent census data from 2010 (as available), rather than data from 2000

. Response: Our risk

- based demographic analysis for the Wool Fiberglass Manufacturing source category included both area and major sources. With regard to the commenter’s suggestion regarding overall health and elements to include in the EJ analysis, see our response
to comment s in section VI.B.8 of this document . We also note that we updated the demographics analysis to use the 2010 census data. The memorandum “ Risk and Technology Review

— Analysis of Socio

- Economic Factors for Populations Living Near Wool Fiberglass Facilities” date d March 23, 2015 summarizes the results and is available in the docket.

174. Comment : One commenter (1042

- 0299) expressed concern that the EPA’s residual risk assessment (docket ID EPA

- HQ

- OAR

- 2010

- 1042

- 0263) does not explain how the EPA calculated the results that showed that emissions from some facilities could cause cancer risk of 200

- 400

- in

- 1 million, and emissions from almost all other facil i ties cause a cancer risk of 1

- in

- 1 million or higher

. Response: The EPA described the auxiliary risk characterization in section 4.3 of the 2011 memorandum “Draft Residual Risk Assessment for the Mineral Wool Production and Wool Fiberglass Manufacturing Source Categories,” (available in the docket for this rulemaking as EPA

- HQ

- OAR

- 2010

- 1042

- 0086). For the 2013 proposal, we revised our analysis to incorporate new emissions data that we received for one of the furnaces at the facility with the highest hexavalent chromium emissions, and we prepared a table of our results for each of 28 area and major source facilities “Maxim um Predicted HEM

- 3 Chronic Risks (Wool Fiberglass Manufacturing) based on Revised

– What If Analysis,” available in the docket for this rulemaking (EPA

- HQ

- OAR

- 2010

- 1042

- 0263).

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