NESHAP for Brick and Structural Clay Products Manufacturing; and NESHAP for Clay Ceramics Manufacturing

Federal RegisterDec 18, 2014

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2013-0290 and EPA-HQ-OAR-2013-0291; FRL-9913-58-OAR]

RIN 2060-AP69

NESHAP for Brick and Structural Clay Products Manufacturing; and NESHAP for Clay Ceramics Manufacturing

AGENCY:

Environmental Protection Agency.

ACTION:

Proposed rule.

SUMMARY:

The Environmental Protection Agency (EPA) is proposing national emission standards for hazardous air pollutants (NESHAP) for brick and structural clay products manufacturing and NESHAP for clay ceramics manufacturing. The EPA is proposing that all major sources in these categories meet maximum achievable control technology (MACT) standards for mercury, non-mercury metal hazardous air pollutants (HAP) (or particulate matter (PM) surrogate) and dioxins/furans (Clay Ceramics only); health-based standards for acid gas HAP; and work practice standards, where applicable. The proposed rule, which has been informed by input from industry and other stakeholders, including small businesses, would protect air quality and promote public health by reducing emissions of HAP listed in section 112 of the Clean Air Act (CAA).

DATES:

Comments.

Comments must be received on or before February 17, 2015. A copy of comments on the information collection provisions should be submitted to the Office of Management and Budget (OMB) on or before January 20, 2015.

Public Hearing.

If anyone contacts the EPA requesting a public hearing by January 15, 2014 the EPA will hold a public hearing on January 20, 2015 from 1:00 p.m. [Eastern Standard Time] to 5:00 p.m. [Eastern Standard Time] at the U.S. Environmental Protection Agency building located at 109 T.W. Alexander Drive, Research Triangle Park, NC 27711. If the EPA holds a public hearing, the EPA will keep the record of the hearing open for 30 days after completion of the hearing to provide an opportunity for submission of rebuttal and supplementary information.

ADDRESSES:

Comments.

Submit your comments, identified by Docket ID No. EPA-HQ-OAR-2013-0291 for Brick and Structural Clay Products Manufacturing and EPA-HQ-OAR-2013-0290 for Clay Ceramics Manufacturing, by one of the following methods:

•

Federal eRulemaking Portal: http://www.regulations.gov:

Follow the on-line instructions for submitting comments.

•

Email: A-and-R-docket@epa.gov

. Include Docket ID No. EPA-HQ-OAR-2013-0291 for Brick and Structural Clay Products Manufacturing or EPA-HQ-OAR-2013-0290 for Clay Ceramics Manufacturing in the subject line of the message.

•

Fax:

(202) 566-9744.

•

Mail:

Environmental Protection Agency, EPA Docket Center (EPA/DC), Mailcode 28221T, Attention Docket ID No. EPA-HQ-OAR-2013-0291 (for Brick and Structural Clay Products Manufacturing) or EPA-HQ-OAR-2013-0290 (for Clay Ceramics Manufacturing), 1200 Pennsylvania Ave. NW., Washington, DC 20460. In addition, please mail a copy of your comments on the information collection provisions to the Office of Information and Regulatory Affairs, Office of Management and Budget (OMB), Attn: Desk Officer for EPA, 725 17th Street NW., Washington, DC 20503.

•

Hand/Courier Delivery:

EPA Docket Center, Room 3334, EPA WJC West Building, 1301 Constitution Ave. NW., Washington, DC 20004. Such deliveries are only accepted during the Docket's normal hours of operation and special arrangements should be made for deliveries of boxed information.

Instructions.

Direct your comments to Docket ID No. EPA-HQ-OAR-2013-0291 for Brick and Structural Clay Products Manufacturing or EPA-HQ-OAR-2013-0290 for Clay Ceramics Manufacturing. The EPA's policy is that all comments received will be included in the public docket without change and may be made available online at

http://www.regulations.gov,

including any personal information provided, unless the comment includes information claimed to be confidential business information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through

http://www.regulations.gov

or email. The

http://www.regulations.gov

Web site is an “anonymous access” system, which means the EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an email comment directly to the EPA without going through

http://www.regulations.gov,

your email address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, the EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If the EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, the EPA may not be able to consider your comment. Electronic files should not include special characters or any form of encryption and be free of any defects or viruses. For additional information about the EPA's public docket, visit the EPA Docket Center homepage at:

http://www.epa.gov/dockets.

Docket.

The EPA has established dockets for this rulemaking under Docket ID No. EPA-HQ-OAR-2013-0291 for Brick and Structural Clay Products Manufacturing and Docket ID No. EPA-HQ-OAR-2013-0290 for Clay Ceramics Manufacturing. All documents in the dockets are listed in the regulations.gov index. Although listed in the index, some information is not publicly available,

e.g.,

CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy. Publicly available docket materials are available either electronically in regulations.gov or in hard copy at the EPA Docket Center, EPA WJC West Building, Room 3334, 1301 Constitution Ave. NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744 and the telephone number for the EPA Docket Center is (202) 566-1742.

Public Hearing.

If requested by January 15, 2014, we will hold a public hearing on January 20, 2015, from 1:00 p.m. [Eastern Standard Time] to 5:00 p.m. [Eastern Standard Time] at the U.S. Environmental Protection Agency building located at 109 T.W. Alexander Drive, Research Triangle Park, NC 27711. Please contact Ms. Pamela Garrett of the Sector Policies and Programs Division (D243-01), Office of Air Quality Planning and Standards, Environmental Protection Agency, Research Triangle Park, NC 27711; telephone number: (919) 541-7966; email address:

garrett.pamela@epa.gov;

to request a hearing, register to speak at the hearing or to inquire as to whether or not a hearing will be held. The last day to pre-register in advance to speak at the hearing will be December 30, 2014. Additionally, requests to speak will be taken the day of the hearing at the hearing registration desk, although

preferences on speaking times may not be able to be fulfilled. If you require the service of a translator or special accommodations such as audio description, we ask that you pre-register for the hearing, as we may not be able to arrange such accommodations without advance notice. The hearing will provide interested parties the opportunity to present data, views or arguments concerning the proposed action. The EPA will make every effort to accommodate all speakers who arrive and register. Because this hearing is being held at a U.S. government facility, individuals planning to attend the hearing should be prepared to show valid picture identification to the security staff in order to gain access to the meeting room. Please note that the REAL ID Act, passed by Congress in 2005, established new requirements for entering federal facilities. If your driver's license is issued by Alaska, American Samoa, Arizona, Kentucky, Louisiana, Maine, Massachusetts, Minnesota, Montana, New York, Oklahoma or the state of Washington, you must present an additional form of identification to enter the federal building. Acceptable alternative forms of identification include: Federal employee badges, passports, enhanced driver's licenses and military identification cards. In addition, you will need to obtain a property pass for any personal belongings you bring with you. Upon leaving the building, you will be required to return this property pass to the security desk. No large signs will be allowed in the building, cameras may only be used outside of the building and demonstrations will not be allowed on federal property for security reasons. The EPA may ask clarifying questions during the oral presentations, but will not respond to the presentations at that time. Written statements and supporting information submitted during the comment period will be considered with the same weight as oral comments and supporting information presented at the public hearing. Verbatim transcripts of the hearing and written statements will be included in the docket for the rulemaking. The EPA will make every effort to follow the schedule as closely as possible on the day of the hearing; however, please plan for the hearing to run either ahead of schedule or behind schedule. Again, a hearing will not be held on this rulemaking unless requested. A hearing needs to be requested by December 23, 2014. Again, please contact Ms. Pamela Garrett of the Sector Policies and Programs Division (D243-01), Office of Air Quality Planning and Standards, Environmental Protection Agency, Research Triangle Park, NC 27711; telephone number: (919) 541-7966; email address:

garrett.pamela@epa.gov

to request a hearing.

FOR FURTHER INFORMATION CONTACT:

For questions about the proposed rule for Brick and Structural Clay Products Manufacturing and Clay Ceramics Manufacturing, contact Ms. Sharon Nizich, Minerals and Manufacturing Group, Sector Policies and Program Division (D243-04), Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711; Telephone number: (919) 541-2825; Fax number: (919) 541-5450; Email address:

nizich.sharon@epa.gov.

SUPPLEMENTARY INFORMATION:

Preamble Acronyms and Abbreviations.

This preamble includes several acronyms and terms used to describe industrial processes, data inventories and risk modeling. While this list may not be exhaustive, to ease the reading of this preamble and for reference purposes, the EPA defines the following terms and acronyms here:

3×RDL representative detection level values multiplied by three

ACI activated carbon injection

AEGL Acute Exposure Guideline Level

AERMOD air dispersion model used by the HEM-3 model

APCD air pollution control device

ATSDR Agency for Toxic Substances and Disease Registry

BDL below detection limit

BLD bag leak detection

BSCP brick and structural clay products

CAA Clean Air Act

CalEPA California EPA

CAS Chemical Abstract Services

CBI Confidential Business Information

CDX Central Data Exchange

CEDRI Compliance and Emissions Data Reporting Interface

CFR Code of Federal Regulations

chlorine

CO carbon monoxide

CPMS continuous parameter monitoring system

DHHS Department of Health and Human Services

DIFF dry lime injection fabric filter

DLA dry limestone adsorber

DLL detection level limited

DLS/FF dry lime scrubber/fabric filter

EPA Environmental Protection Agency

ERPG Emergency Response Planning Guideline

ERT Electronic Reporting Tool

°F degrees Fahrenheit

FF fabric filter

FTIR Fourier transform infrared

gr/dscf grains per dry standard cubic foot

HAP hazardous air pollutant

HCl hydrogen chloride

HEM-3 Human Exposure Model (Community and Sector version 1.3.1)

HF hydrogen fluoride

Hg mercury

HQ hazard quotient

IARC International Agency for Research on Cancer

ICR information collection request

IOM Institute of Medicine

IRFA initial regulatory flexibility analysis

IRIS Integrated Risk Information System

K kurtosis statistic

lb/hr pounds per hour

lb/ton pounds per ton

LML lowest measured level

MACT maximum achievable control technology

mg/m

milligrams per cubic meter

MMBtu/yr million British thermal units per year

MRL Minimal Risk Level

NAAQS National Ambient Air Quality Standards

NAICS North American Industry Classification System

NATA National Air Toxics Assessment

NEI National Emissions Inventory

NESHAP national emissions standards for hazardous air pollutants

ng/dscm nanograms per dry standard cubic meter

No. number

nitrogen dioxide

NOAEL no observable adverse effect level

non-Hg non-mercury

nitrogen oxides

NTTAA National Technology Transfer and Advancement Act

oxygen

OM&M operation, maintenance and monitoring

OMB Office of Management and Budget

PIC products of incomplete combustion

PLC programmable logic controller

PM particulate matter

2.5

particulate matter with particles less than 2.5 micrometers in diameter

RDL representative detection level

REL reference exposure level

RFA Regulatory Flexibility Act

RfC reference concentration

RIA Regulatory Impact Analysis

S skewness statistic

SBA Small Business Administration

SBAR Small Business Advocacy Review

SBE Standard Brick Equivalent

SBREFA Small Business Regulatory Enforcement Fairness Act

SEK standard error of kurtosis

SER small entity representative

SES standard error of skewness

sulfur dioxide

SSM startup, shutdown and malfunction

TCDD tetrachlorodibenzo-p-dioxin

TEQ 2,3,7,8-TCDD toxic equivalents

TOSHI target organ-specific hazard index

tph tons per hour

tpy tons per year

TTN Technology Transfer Network

UMRA Unfunded Mandates Reform Act

μg/dscm micrograms per dry standard cubic meter

μg/m

micrograms per cubic meter

UPL Upper Prediction Limit

VCS voluntary consensus standards

VE visible emissions

WHO World Health Organization

Organization of This Document.

The information in this preamble is organized as follows:

I. General Information

A. Executive Summary

B. Does this action apply to me?

C. Where can I get a copy of this document and other related information?

D. What should I consider as I prepare my comments for the EPA?

II. Background Information

A. What is the statutory authority for the proposed rule?

B. What is the background for startup, shutdown and malfunction?

C. What is the history of the proposed rule?

D. What are the health effects of pollutants emitted from the Brick and Structural Clay Products and Clay Ceramics Manufacturing source categories?

III. Summary of the Proposed Rule for the Brick and Structural Clay Products Manufacturing Source Category

A. What source category is affected by the proposed rule?

B. What are the affected sources?

C. Does the proposed rule apply to me?

D. What emission limitations and work practice standards must I meet?

E. What are the startup and shutdown requirements?

F. What are the testing and initial compliance requirements?

G. What are the continuous compliance requirements?

H. What are the notification, recordkeeping and reporting requirements?

I. How would I submit emissions test results to the EPA?

IV. Rationale for the Proposed Rule for Brick and Structural Clay Products Manufacturing

A. How did the EPA determine which sources would be regulated under the proposed rule?

B. How did the EPA select the format for the proposed rule?

C. How did the EPA consider different subcategories?

D. What approaches did the EPA consider in developing the proposed emission limitations for existing and new sources?

E. How did the EPA determine the MACT floors for existing sources?

F. How did the EPA determine the MACT floor for new sources?

G. What is our approach for applying the upper prediction limit to limited datasets?

H. How did the EPA consider beyond-the-floor for existing sources?

I. How did the EPA consider beyond-the-floor for new sources?

J. How did the EPA determine whether to set health-based standards for existing and new sources?

K. How did the EPA determine whether to set work practice standards for existing and new sources?

L. How did the EPA develop the startup and shutdown requirements?

M. How did the EPA select the compliance requirements?

N. How did the EPA determine compliance times for the proposed rule?

O. How did the EPA determine the required records and reports for the proposed rule?

P. How does the proposed rule affect permits?

Q. What are the alternate approaches the EPA is considering?

V. Summary of the Proposed Rule for the Clay Ceramics Manufacturing Category

A. What source category is affected by the proposed rule?

B. What are the affected sources?

C. Does the proposed rule apply to me?

D. What emission limitations and work practice standards must I meet?

E. What are the startup and shutdown requirements?

F. What are the testing and initial compliance requirements?

G. What are the continuous compliance requirements?

H. What are the notification, recordkeeping and reporting requirements?

I. How would I submit emissions test results to the EPA?

VI. Rationale for the Proposed Rule for Clay Ceramics Manufacturing

A. How did the EPA determine which sources would be regulated under the proposed rule?

B. How did the EPA select the format for the proposed rule?

C. How did the EPA consider different subcategories?

D. What approaches did the EPA consider in developing the proposed emission limitations for existing and new sources?

E. How did the EPA determine the MACT floors for existing sources?

F. How did the EPA determine the MACT floors for new sources?

G. What is our approach for applying the upper prediction limit to limited datasets?

H. How did the EPA consider beyond-the-floor for existing sources?

I. How did the EPA consider beyond-the-floor for new sources?

J. How did the EPA determine whether to set health-based standards for existing and new sources?

K. How did the EPA determine whether to set work practice standards for existing and new sources?

L. How did the EPA develop the startup and shutdown requirements?

M. How did the EPA select the compliance requirements?

N. How did the EPA determine compliance times for the proposed rule?

O. How did the EPA determine the required records and reports for the proposed rule?

P. How does the proposed rule affect permits?

VII. Summary of the Environmental, Energy and Economic Impacts of the Proposed Standards

A. What are the cost and emission reduction impacts?

B. What are the secondary impacts?

C. What are the economic impacts?

D. What are the social costs and benefits of the proposed rule?

VIII. Public Participation and Request for Comment

IX. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: Improving Regulation and Regulatory Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments

G. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks

H. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution or Use

I. National Technology Transfer and Advancement Act

J. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations

I. General Information

A. Executive Summary

1. Purpose of the Regulatory Action

Section 112(d) of the CAA requires the EPA to set emissions standards for HAP emitted by major stationary sources based on the performance of the MACT. We issued the NESHAP for Brick and Structural Clay Products (BSCP) manufacturing and the NESHAP for Clay Ceramics Manufacturing on May 16, 2003. The two NESHAP were vacated and remanded by the United States Court of Appeals for the District of Columbia Circuit on March 13, 2007. To address the vacatur and remand of the original NESHAP, we are proposing new standards for BSCP manufacturing and clay ceramics manufacturing.

2. Summary of the Major Provisions

BSCP NESHAP.

The EPA is proposing MACT emission limits for mercury (Hg) and non-mercury (non-Hg) HAP metals (or PM surrogate) and a health-based emission limit for acid gases (hydrogen fluoride (HF), hydrogen chloride (HCl) and chlorine (Cl

)) for BSCP tunnel kilns. In addition, the EPA is proposing work practice standards for periodic kilns, for dioxins/furans from tunnel kilns and for periods of startup and shutdown for tunnel kilns. To demonstrate compliance with the emission limits, the EPA is proposing initial and repeat 5-year performance testing for the regulated pollutants, continuous parameter monitoring and daily visible emissions (VE) checks. Owners/operators whose BSCP tunnel kilns are equipped with a fabric filter (FF) (

e.g.,

dry lime injection fabric filter (DIFF), dry lime scrubber/fabric filter (DLS/FF)) have the option of

demonstrating compliance using a bag leak detection (BLD) system instead of daily VE checks.

Clay Ceramics NESHAP.

The EPA is proposing MACT emission limits for Hg, PM (surrogate for non-Hg HAP metals) and dioxins/furans and health-based emission limits for acid gases (HF and HCl) for sanitaryware tunnel kilns and ceramic tile roller kilns. In addition, the EPA is proposing MACT emission limits for dioxins/furans for ceramic tile spray dryers and floor tile press dryers, MACT emission limits for Hg and PM (surrogate for non-Hg HAP metals) for ceramic tile glaze lines and MACT emission limits for PM (surrogate for non-Hg HAP metals) for sanitaryware glaze spray booths. The EPA is also proposing work practice standards for shuttle kilns and for periods of startup and shutdown. To demonstrate compliance with the emission limits, the EPA is proposing initial and repeat 5-year performance testing for the regulated pollutants, continuous parameter monitoring and daily VE checks. Owners/operators whose affected sources are equipped with a FF (

e.g.,

DIFF, DLS/FF) have the option of demonstrating compliance using a BLD system instead of daily VE checks.

3. Costs and Benefits

Table 1 of this preamble summarizes the costs and benefits of this proposed action for 40 CFR part 63, subpart JJJJJ (BSCP Manufacturing NESHAP), while Table 2 of this preamble summarizes the costs of this proposed action for 40 CFR part 63, subpart KKKKK (Clay Ceramics Manufacturing NESHAP). See section VII of this preamble for further discussion of the costs and benefits for the BSCP Manufacturing NESHAP and the costs for the Clay Ceramics Manufacturing NESHAP. See section IX.B of this preamble for discussion of the recordkeeping and reporting costs.

Table 1—Summary of the Costs and Benefits of 40 CFR Part 63, Subpart JJJJJ

[Millions of 2011 dollars]

Requirement

Capital cost

Annual cost

Net benefit

Emission controls

$54.9

$18.4

$26 to $99.

Emissions testing

0.977

0.238

Monitoring

0.346

Table 2—Summary of the Costs of 40 CFR Part 63, Subpart KKKKK

[Millions of 2011 dollars]

Requirement

Capital cost

Annual cost

Emission controls

Emissions testing

0.102

0.0249

Monitoring

0.0209

B. Does this action apply to me?

The regulated categories and entities potentially affected by the proposed standards are shown in Table 3 of this preamble:

Table 3—NESHAP and Industrial Source Categories Affected by This Proposed Action

See also, Weyerhaeuser

Costle,

590 F.2d 1011, 1058 (D.C. Cir. 1978) (“In the nature of things, no general limit, individual permit, or even any upset provision can anticipate all upset situations. After a certain point, the transgression of regulatory limits caused by `uncontrollable acts of third parties,' such as strikes, sabotage, operator intoxication or insanity, and a variety of other eventualities, must be a matter for the administrative exercise of case-by-case enforcement discretion, not for specification in advance by regulation.”). In addition, emissions during a malfunction event can be significantly higher than emissions at any other time of source operation. For example, if an air pollution control device with 99-percent removal goes off-line as a result of a malfunction (as might happen if, for example, the bags in a baghouse catch fire) and the emission unit is a steady state type unit that would take days to shut down, the source would go from 99-percent control to zero control until the control device was repaired. The source's emissions during the malfunction would be 100 times higher than during normal operations, and the emissions over a 4-day malfunction period would exceed the annual emissions of the source during normal operations. As this example illustrates, accounting for malfunctions could lead to standards

that are not reflective of (and significantly less stringent than) levels that are achieved by a well-performing non-malfunctioning source. It is reasonable to interpret CAA section 112 to avoid such a result. The EPA's approach to malfunctions is consistent with CAA section 112 and is a reasonable interpretation of the statute.

In the event that a source fails to comply with the applicable CAA section 112 standards as a result of a malfunction event, the EPA would determine an appropriate response based on, among other things, the good faith efforts of the source to minimize emissions during malfunction periods, including preventative and corrective actions, as well as root cause analyses to ascertain and rectify excess emissions. The EPA would also consider whether the source's failure to comply with the CAA section 112(d) standard was, in fact, “sudden, infrequent, not reasonably preventable” and was not instead “caused in part by poor maintenance or careless operation.” 40 CFR 63.2 (definition of malfunction).

If the EPA determines in a particular case that enforcement action against a source for violation of an emission standard is warranted, the source can raise any and all defenses in that enforcement action and the federal district court will determine what, if any, relief is appropriate. The same is true for citizen enforcement actions. Similarly, the presiding officer in an administrative proceeding can consider any defense raised and determine whether administrative penalties are appropriate.

In summary, the EPA interpretation of the CAA and, in particular, section 112 is reasonable and encourages practices that will avoid malfunctions. Administrative and judicial procedures for addressing exceedances of the standards fully recognize that violations may occur despite good faith efforts to comply and can accommodate those situations.

C. What is the history of the proposed rule?

Pursuant to CAA section 112(c)(5), the EPA was originally required to promulgate standards for the BSCP Manufacturing and Clay Ceramics Manufacturing source categories by November 2000. The agency initially promulgated standards for these categories in 2003. See 68 FR 26690 (May 16, 2003). Those standards were challenged and subsequently vacated by the Court of appeals for the District of Columbia Circuit in 2007.

See Sierra Club

EPA,

479 F.3d 875, 876 (D.C. Cir. 2007). In 2008, Sierra Club filed suit in the Court of Appeals for the District of Columbia Circuit under CAA section 304(a)(2), alleging that the EPA had a continuing mandatory duty to promulgate standards for these categories under CAA section 112 based on the 2000 deadline under CAA section 112(c)(5). The EPA challenged that claim in a motion to dismiss, arguing that the mandatory duty to act by the 2000 deadline was satisfied by the 2003 rule and that the 2007 vacatur of the 2003 rule did not recreate the statutory duty to act by the 2000 deadline. Ultimately, the District Court found that the vacatur of the 2003 rule recreated the mandatory duty to set standards by 2000 and held that Sierra Club's claims could continue.

See Sierra Club

EPA,

850 F.Supp.2d 300 (D.D.C. 2012). The EPA and Sierra Club then negotiated a consent decree to settle the litigation and establish proposal and promulgation deadlines for establishing standards for these categories.

Following the 2007 vacatur of the 2003 rule, the EPA began efforts to collect additional data to support new standards for the BSCP and clay ceramics industries. The EPA conducted an initial information collection effort in 2008 to update information on the inventory of affected units, hereafter referred to as “the 2008 EPA survey.” The EPA conducted a second information collection effort in 2010 to obtain additional emissions data and information on each facility's SSM procedures, hereafter referred to as “the 2010 EPA survey.” The information collected as part of these surveys and not claimed as CBI by respondents is available in Docket ID Nos. EPA-HQ-OAR-2013-0290 and EPA-HQ-OAR-2013-0291. In addition, the dockets A-99-30 and OAR-2002-0054 are incorporated by reference for BSCP. The dockets A-2000-48, OAR-2002-0055 and EPA-HQ-OAR-2006-0424 are incorporated by reference for clay ceramics.

D. What are the health effects of pollutants emitted from the Brick and Structural Clay Products Manufacturing and Clay Ceramics Manufacturing source categories?

The proposed rule protects air quality and promotes the public health by reducing emissions of HAP emitted from BSCP and clay ceramics kilns. Emissions data collected during development of the proposed rule shows that acid gases such as HF, HCl and Cl

represent the predominant HAP emitted by BSCP and clay ceramics kilns, accounting for 99.3 percent of the total HAP emissions. These kilns also emit lesser amounts of other HAP compounds such as HAP metals and dioxins/furans, accounting for about 0.7 percent of total HAP emissions. The HAP metals emitted include antimony, arsenic, beryllium, cadmium, chromium, cobalt, lead, manganese, mercury, nickel and selenium. Exposure to these HAP, depending on exposure duration and levels of exposures, can be associated with a variety of adverse health effects. These adverse health effects could include chronic health disorders (

e.g.,

irritation of the lung, skin and mucus membranes, effects on the central nervous system and damage to the kidneys) and acute health disorders (

e.g.,

lung irritation and congestion, alimentary effects such as nausea and vomiting and effects on the kidney and central nervous system). We have classified two of the HAP as human carcinogens (arsenic and chromium VI) and four as probable human carcinogens (cadmium, lead, dioxins/furans and nickel).

III. Summary of the Proposed Rule for the Brick and Structural Clay Products Manufacturing Source Category

This section summarizes the requirements for the BSCP Manufacturing source category proposed in today's action. Section IV of this preamble provides our rationale for the proposed requirements.

A. What source category is affected by the proposed rule?

Today's proposed rule for BSCP Manufacturing applies to BSCP manufacturing facilities that are located at or are part of a major source of HAP emissions. The BSCP Manufacturing source category includes those facilities that manufacture brick (face brick, structural brick, brick pavers and other brick); clay pipe; roof tile; extruded floor and wall tile; and/or other extruded, dimensional clay products.

B. What are the affected sources?

The affected sources, which are the portions of each source in the category for which we are setting standards, are: (1) all tunnel kilns at a BSCP manufacturing facility; and (2) each periodic kiln. For purposes of this proposed BSCP manufacturing rule, tunnel kilns are defined to include any type of continuous kiln used at BSCP manufacturing facilities, including roller kilns.

Tunnel kilns are fired by natural gas or other fuels, including sawdust. Sawdust firing typically involves the use of a sawdust dryer because sawdust typically is purchased wet and needs to be dried before it can be used as fuel.

Consequently, some sawdust-fired tunnel kilns have two process streams, including: (1) A process stream that exhausts directly to the atmosphere or to an APCD and (2) a process stream in which the kiln exhaust is ducted to a sawdust dryer where it is used to dry sawdust before being emitted to the atmosphere. Both process streams are subject to the requirements of today's proposed BSCP manufacturing rule.

The following BSCP process units are not subject to the requirements of today's proposed rule: (1) kilns that are used exclusively for setting glazes on previously fired products and (2) dryers. See section IV.A of this preamble for information on why these sources are not subject to the proposed BSCP manufacturing rule.

C. Does the proposed rule apply to me?

This proposed BSCP manufacturing rule applies to owners or operators of an affected source at a major source meeting the requirements discussed previously in this preamble. A major source of HAP emissions is 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, 10 tons per year (tpy) or more of any HAP or 25 tpy or more of any combination of HAP.

D. What emission limitations and work practice standards must I meet?

1. Emission Limitations

We are proposing a choice of emission limits for total non-Hg HAP metals for all new and existing tunnel kilns. The options include a total non-Hg HAP metals limit (pounds per hour (lb/hr)) and options for limiting PM as a surrogate for non-Hg HAP metals (pounds per ton (lb/ton) or grains per dry standard cubic foot (gr/dscf) at 7 percent oxygen (O

)). We are also proposing a choice of emission limits for Hg (lb/ton, lb/hr or micrograms per dry standard cubic meter (µg/dscm) at 7 percent O

) for new and existing tunnel kilns in two subcategories based on kiln size. In this proposed BSCP manufacturing rule, a large tunnel kiln is defined as a new or existing tunnel kiln with a design capacity of 10 tons per hour (tph) or greater and a small tunnel kiln is defined as a new or existing tunnel kiln with a design capacity of less than 10 tph. We are also proposing an emission limit for HCl-equivalent for all existing and new tunnel kilns at the facility to reduce the acid gases HF, HCl and Cl

. The proposed emission limits for Hg and non-Hg HAP metals are presented in Table 4 of this preamble.

Table 4—Proposed Total Non-Mercury HAP Metals and Mercury Emission Limits for Brick and Structural Clay Products Tunnel Kilns

Subcategory

Acid gases

Total non-Hg HAP metals

Limits for existing sources

Large tunnel kilns

(≥ 10 tph)

2.2 E-05 lb/ton OR 2.7 E-04 lb/hr OR 29 µg/dscm at 7-percent O

for each existing large tunnel kiln at facility.

Small tunnel kilns

(< 10 tph)

2.0 E-04 lb/ton OR 0.0011 lb/hr OR 70 µg/dscm at 7-percent O

for each existing small tunnel kiln at facility.

All tunnel kilns

57 lb/hr HCl-equivalent for collection of all existing tunnel kilns at facility

0.16 lb/ton PM OR 0.040 gr/dscf PM at 7 percent O

OR 0.023 lb/hr non-Hg HAP metals for each existing tunnel kiln at facility

Limits for new sources

Large tunnel kilns

(≥ 10 tph)

2.0 E-05 lb/ton OR 2.4 E-04 lb/hr OR 13 µg/dscm at 7-percent O

for each new large tunnel kiln at facility.

Small tunnel kilns

(< 10 tph)

2.0 E-04 lb/ton OR 0.0011 lb/hr OR 70 µg/dscm at 7-percent O

for each new small tunnel kiln at facility.

All tunnel kilns

57 lb/hr HCl-equivalent for collection of all new tunnel kilns at facility

0.022 lb/ton PM OR 0.0066 gr/dscf PM at 7-percent O

OR 0.0032 lb/hr non-Hg HAP metals for each new tunnel kiln at facility

2. Work Practice Standards

We are proposing work practice standards for BSCP periodic kilns in lieu of HAP emission limits. The work practice standards would require developing and using a designed firing time and temperature cycle for each product produced in the periodic kiln; labeling each periodic kiln with the maximum load (in tons) that can be fired in the kiln during a single firing cycle; documenting the total tonnage placed in the kiln for each load to ensure that it is not greater than the maximum load; developing and implementing maintenance procedures for each kiln that specify the frequency of inspection and maintenance; and developing and maintaining records for each periodic kiln, including logs to document the proper operation and maintenance procedures of the periodic kilns.

We are also proposing work practice standards for BSCP tunnel kilns in lieu of dioxin/furan emission limits. The

work practice standards would require maintaining and inspecting the burners and associated combustion controls (as applicable); tuning the specific burner type to optimize combustion; keeping records of each burner tune-up; and submitting a report for each tune-up conducted.

E. What are the startup and shutdown requirements?

The EPA's position on SSM events is discussed in section II.B of this preamble. Standards for periods of startup and shutdown are discussed in this section.

We are proposing the work practice standards described in this paragraph for periods of startup and shutdown for BSCP tunnel kilns with APCD. For startup, the owner or operator would be required to vent the exhaust from the kiln through the APCD by the time the kiln exhaust temperature reaches 400 degrees Fahrenheit (°F). In addition, no bricks or other product may be introduced to the kiln until the kiln exhaust temperature reaches 400 °F and the exhaust is being vented through the APCD. For shutdown, the owner or operator would be required to vent the exhaust from the kiln through the APCD until the kiln exhaust temperature falls below 300 °F. In addition, no bricks or other product may be put into the kiln once the kiln exhaust temperature falls to 300 °F and the exhaust is no longer being vented through the APCD. When the kiln exhaust is being vented through the APCD, the owner or operator would be required to comply with the applicable continuous compliance requirements described in section III.G of this preamble.

We are proposing work practice standards for periods of startup and shutdown for BSCP tunnel kilns without an APCD as well. For startup, no bricks or other product may be introduced to the kiln until the kiln exhaust temperature reaches 400 °F. For shutdown, no bricks or other product may be put into the kiln once the kiln exhaust temperature falls to 300 °F.

F. What are the testing and initial compliance requirements?

We are proposing that owners or operators of all affected sources subject to emission limits conduct an initial performance test using specified EPA test methods to demonstrate initial compliance with all applicable emission limits. A performance test would have to be conducted before renewing the facility's 40 CFR part 70 operating permit or at least every five years following the initial performance test, as well as when an operating limit parameter value is being revised.

Under today's proposed BSCP manufacturing rule, the owner or operator would have to measure emissions of HF, HCl, Cl

, Hg and PM (or non-Hg HAP metals). We are proposing that the owner or operator measure HF, HCl and Cl

using one of the following methods:

• EPA Method 26A, “Determination of Hydrogen Halide and Halogen Emissions from Stationary Sources—Isokinetic Method,” 40 CFR part 60, appendix A-8;

• EPA Method 26, “Determination of Hydrogen Chloride Emissions from Stationary Sources,” 40 CFR part 60, appendix A-8, when no acid particulate (

e.g.,

HF, HCl or Cl

dissolved in water droplets emitted by sources controlled by a wet scrubber) is present;

• EPA Method 320, “Measurement of Vapor Phase Organic and Inorganic Emission by Extractive FTIR” 40 CFR part 63, appendix A, provided the test follows the analyte spiking procedures of section 13 of Method 320, unless the owner or operator can demonstrate that the complete spiking procedure has been conducted at a similar source; or

• Any other alternative method that has been approved by the Administrator under 40 CFR 63.7(f) of the General Provisions.

Following the performance test, the owner or operator would calculate the HCl-equivalent for the kiln using proposed Equation 2 in 40 CFR 63.8445(f)(2)(i). If there are multiple kilns at a facility, the owner or operator would sum the HCl-equivalent for each kiln using proposed Equation 3 in 40 CFR 63.8445(f)(2)(ii) to get the total facility HCl-equivalent and compare this value to the proposed limitation.

If the owner or operator chooses to comply with one of the two PM emission limits, we are proposing that the owner or operator measure PM emissions using one of the following methods:

• EPA Method 5, “Determination of Particulate Emissions from Stationary Sources,” 40 CFR part 60, appendix A-3;

• EPA Method 29, “Determination of Metals Emissions From Stationary Sources,” 40 CFR part 60, appendix A-8, where the test results would report the weight of the PM on the filter as PM filterable; or

• Any other alternative method that has been approved by the Administrator under 40 CFR 63.7(f) of the General Provisions.

If the owner or operator chooses to comply with the non-Hg HAP metals emission limit instead of one of the PM emission limits, the owner or operator would measure non-Hg HAP metals emissions using EPA Method 29 cited above or any other alternative method that has been approved by the Administrator under 40 CFR 63.7(f) of the General Provisions. The owner or operator may also use Method 29 or any other approved alternative method to measure Hg emissions.

The following paragraphs discuss the initial compliance requirements that we are proposing. Prior to the initial performance test, the owner or operator would need to install the continuous parameter monitoring system (CPMS) equipment to be used to demonstrate continuous compliance with the operating limits. During the initial test, the owner or operator would use the CPMS to establish site-specific operating parameter values that represent the operating limits.

For a DIFF or DLS/FF, we are proposing that the owner or operator ensure that lime in the feed hopper or silo and to the APCD is free-flowing at all times during the HF/HCl/Cl

performance test and record the feeder setting (on a per ton of fired product basis) for the three test runs. If the lime feed rate varies, the owner or operator would be required to determine the average feed rate from the three test runs. The average of the three test runs establishes the minimum site-specific feed rate operating limit. If there are different average feed rate values during the PM/non-Hg HAP metals and HF/HCl/Cl

tests, the highest of the average values becomes the site-specific operating limit. If a BLD system is present, the owner or operator would need to submit analyses and supporting documentation demonstrating conformance with EPA guidance and specifications for BLD systems.

For a stand-alone FF (

i.e.,

no dry sorbent injection or DLS) and a BLD system, we are proposing that the owner or operator submit analyses and supporting documentation demonstrating conformance with EPA guidance and specifications for BLD systems.

For a dry limestone adsorber (DLA), we are proposing that the owner or operator continuously measure the pressure drop across the DLA during the HF/HCl/Cl

performance test and determine the 3-hour block average pressure drop. The average of the three test runs establishes the minimum site-specific pressure drop operating limit. Alternatively, the owner or operator may continuously monitor the bypass stack damper position at least once every 15 minutes during the performance test. The owner or operator also would need to maintain an adequate amount of limestone in the limestone hopper, storage bin (located at the top of the DLA) and DLA at all times. In addition, the owner or operator would need to establish the limestone

feeder setting (on a per ton of fired product basis) 1 week prior to the performance test and maintain the feeder setting for the 1-week period that precedes the performance test and during the performance test. Finally, the owner or operator would need to document the source and grade of the limestone used during the performance test.

For a wet scrubber, we are proposing that the owner or operator continuously measure the scrubber pressure drop during the PM/non-Hg HAP metals performance test, the scrubber liquid pH and chemical addition rate (if applicable) during the HF/HCl/Cl

performance test and the scrubber liquid flow rate during both the PM/non-Hg HAP metals and HF/HCl/Cl

performance tests. For each wet scrubber parameter, the owner or operator would need to determine and record the average values for the three test runs and the 3-hour block average value. The average of the three test runs establishes the minimum site-specific pressure drop, liquid pH, liquid flow rate and chemical addition rate operating limits. If different average wet scrubber liquid flow rate values are measured during the PM/non-Hg HAP metals and HF/HCl/Cl

tests, the highest of the average values become the site-specific operating limit.

For an activated carbon injection (ACI) system, we are proposing that the owner or operator measure the activated carbon flow rate during the Hg performance test and determine the 3-hour block average flow rate. The average of the three test runs establishes the minimum site-specific activated carbon flow rate operating limit.

For a source with no APCD installed, we are proposing that the owner or operator calculate the maximum potential HCl-equivalent using proposed Equation 4 in 40 CFR 63.8445(g)(1)(i). The owner or operator would use the results from the performance test to determine the emissions at the maximum possible process rate. For example, if the design capacity of the kiln is 10 tph and the production rate during the performance test was 9 tph, then the test results represent 90 percent of the maximum potential emissions. If there are multiple kilns at a facility, the owner or operator would need to sum the maximum potential HCl-equivalent for each kiln to get the total facility maximum potential HCl-equivalent and compare this value to the proposed health-based emission limitation for acid gases. If the total facility maximum potential HCl-equivalent is greater than the proposed limitation, we are proposing that the owner or operator determine the maximum process rate for which the total facility maximum potential HCl-equivalent remains at or below the proposed limitation. If there are multiple kilns, the owner or operator would need to determine one or more combinations of maximum process rates that would result in a total facility maximum potential HCl-equivalent remains at or below the proposed limitation. The maximum process rate(s) would become the operating limit(s) for process rate.

G. What are the continuous compliance requirements?

Today's BSCP manufacturing rule proposes that the owner or operator demonstrate continuous compliance with each emission limitation that applies. The owner or operator would have to follow the requirements in the operation, maintenance and monitoring (OM&M) plan and document conformance with the OM&M plan. The owner or operator would need to operate a CPMS to monitor the operating parameters established during the initial performance test as described in the following paragraphs. The CPMS would have to collect data at least every 15 minutes, including at least three of four equally spaced data values (or at least 75 percent if there are more than four data values per hour) per hour to have a valid hour of data. The owner or operator would have to operate the CPMS at all times when the process is operating. The owner or operator would also have to conduct proper maintenance of the CPMS (including inspections, calibrations and validation checks) and maintain an inventory of necessary parts for routine repairs of the CPMS. Using the recorded readings, the owner or operator would need to calculate and record the 3-hour block average values of each operating parameter. To calculate the average for each 3-hour averaging period, the owner or operator would need to have at least 75 percent of the recorded readings for that period.

For a DIFF or DLS/FF, we are proposing that the owner or operator demonstrate compliance with the acid gas (HF/HCl/Cl

) health-based emission limit by maintaining free-flowing lime in the feed hopper or silo and to the APCD at all times. If lime is not flowing freely, according to load cell output, carrier gas/lime flow indicator, carrier gas pressure drop measurement system or other system, the owner or operator would have to promptly initiate and complete corrective actions according to the OM&M plan. The owner or operator would also have to maintain the feeder setting (on a per ton of fired product basis) at or above the level established during the HF/HCl/Cl

performance test and record the feeder setting once each shift.

The proposed rule would provide the option to use either a BLD system or VE monitoring to demonstrate compliance with the PM/non-Hg HAP metals emission limit.

For the option of a BLD system, we are proposing that the owner or operator initiate corrective action within 1 hour of a BLD system alarm and complete corrective actions according to the OM&M plan. The owner or operator would also need to operate and maintain the FF such that the alarm is not engaged for more than 5 percent of the total operating time in a 6-month block reporting period. In calculating this operating time fraction, the owner or operator would not count any alarm time if inspection of the FF demonstrates that no corrective action is required. If corrective action is required, the owner or operator must count each alarm as a minimum of 1 hour. If corrective action is initiated more than 1 hour after an alarm, the owner or operator must count as alarm time the actual amount of time taken to initiate corrective action.

For the option of monitoring VE, we are proposing that the owner or operator perform daily, 15-minute VE observations in accordance with the procedures of EPA Method 22, “Visual Determination of Fugitive Emissions from Material Sources and Smoke Emissions from Flares,” 40 CFR part 60, appendix A-7. During the VE observations, the kiln would need to be operating under normal conditions. If VE are observed, the owner or operator would have to promptly initiate and complete corrective actions according to the OM&M plan. If no VE are observed in 30 consecutive daily EPA Method 22 tests, the owner or operator may decrease the frequency of EPA Method 22 testing from daily to weekly for that kiln stack. If VE are observed during any weekly test, the owner or operator would have to promptly initiate and complete corrective actions according to the OM&M plan and the owner or operator would need to resume EPA Method 22 testing of that kiln stack on a daily basis until no VE are observed in 30 consecutive daily tests, at which time the owner or operator may again decrease the frequency of EPA Method 22 testing to a weekly basis.

For a stand-alone FF, we are proposing that the owner or operator use a BLD system or monitor VE as described above to demonstrate compliance with the PM/non-Hg HAP metals emission limit.

For a DLA, we are proposing that the owner or operator demonstrate compliance with the acid gas (HF/HCl/Cl

) health-based emission limit by collecting and recording data documenting the DLA pressure drop and reducing the data to 3-hour block averages. The owner or operator would need to maintain the average pressure drop across the DLA for each 3-hour block period at or above the average pressure drop established during the HF/HCl/Cl

performance test. Alternatively, the owner or operator may continuously monitor the bypass stack damper position at least once every 15 minutes during normal kiln operation. Any period in which the bypass damper is opened allowing the kiln exhaust gas to bypass the DLA would trigger corrective actions according to the OM&M plan. The owner or operator also would need to verify that the limestone hopper, storage bin (located at the top of the DLA) and DLA contain an adequate amount of limestone by performing a daily visual check of the limestone hopper and the storage bin. A daily visual check could include one of the following: (1) conducting a physical check of the hopper; (2) creating a visual access point, such as a window, on the side of the hopper; (3) installing a camera in the hopper that provides continuous feed to a video monitor in the control room; or (4) confirming that load level indicators in the hopper are not indicating the need for additional limestone. If the hopper or storage bin does not contain adequate limestone, the owner or operator would have to promptly initiate and complete corrective actions according to the OM&M plan. The owner or operator also would have to record the limestone feeder setting daily (on a per ton of fired product basis) to verify that the feeder setting is being maintained at or above the level established during the HF/HCl/Cl

performance test. The owner or operator also would need to use the same grade of limestone from the same source as was used during the HF/HCl/Cl

performance test and maintain records of the source and type of limestone. Finally, the owner or operator would need to monitor VE, as described in the previous paragraph.

For a wet scrubber, we are proposing that the owner or operator continuously maintain the 3-hour block averages for scrubber pressure drop, scrubber liquid pH, scrubber liquid flow rate and chemical addition rate (if applicable) at or above the minimum values established during the applicable performance test. Maintaining the 3-hour block average for scrubber pressure drop at or above the minimum value established during the PM/non-Hg HAP metals performance test would demonstrate compliance with the PM/non-Hg HAP metals emission limit. Maintaining the 3-hour block average for scrubber liquid pH and chemical (

e.g.,

lime, caustic) addition rate at or above the minimum values established during the HF/HCl/Cl

performance test would demonstrate compliance with the acid gas (HF/HCl/Cl

) health-based emission limit. Maintaining the 3-hour block average for scrubber liquid flow rate at or above the lowest minimum value established during the PM/non-Hg HAP metals and HF/HCl/Cl

performance tests would demonstrate compliance with all applicable emission limits by showing that the scrubber is in proper working order.

For an ACI system, we are proposing that the owner or operator demonstrate compliance with the Hg emission limit by continuously monitoring the activated carbon flow rate and maintaining it at or above the operating limit established during the Hg performance test.

For sources with no APCD, we are proposing that the owner or operator monitor VE as described above to demonstrate compliance with the PM/non-Hg HAP metals emission limit. In addition, if the last calculated total facility maximum potential HCl-equivalent was not at or below the proposed health-based emission limitation for acid gases, then we are proposing that the owner or operator collect and record data documenting the process rate of the kiln and reduce the data to 3-hour block averages. The owner or operator would need to maintain the kiln process rate at or below the kiln process rate operating limit(s) that would enable the total facility maximum potential HCl-equivalent to remain at or below the proposed limitation.

H. What are the notification, recordkeeping and reporting requirements?

All new and existing sources would be required to comply with certain requirements of the General Provisions (40 CFR part 64, subpart A), which are identified in proposed Table 8 of 40 CFR part 64, subpart JJJJJ. The General Provisions include specific requirements for notifications, recordkeeping and reporting.

Each owner or operator would be required to submit a notification of compliance status report, as required by 40 CFR 63.9(h) of the General Provisions. This proposed BSCP manufacturing rule would require the owner or operator to include in the notification of compliance status report certifications of compliance with rule requirements. Semiannual compliance reports, as required by 40 CFR 63.10(e)(3) of subpart A, would also be required for each semiannual reporting period.

This proposed BSCP manufacturing rule would require records to demonstrate compliance with each emission limit and work practice standard. These recordkeeping requirements are specified directly in the General Provisions to 40 CFR part 63 and are identified in proposed Table 8 of subpart JJJJJ.

Specifically, we are proposing that the owner or operator keep the following records:

• All reports and notifications submitted to comply with this proposed BSCP manufacturing rule.

• Records of performance tests.

• Records relating to APCD maintenance and documentation of approved routine control device maintenance exemption.

• Continuous monitoring data as required in this proposed BSCP manufacturing rule.

• Records of BLD system alarms and corrective actions taken.

• Records of each instance in which the owner or operator did not meet each emission limit (

i.e.,

deviations from operating limits).

• Records of production rates.

• Records of approved alternative monitoring or testing procedures.

• Records of maintenance and inspections performed on the APCD.

• Current copies of the OM&M plan and records documenting conformance.

• Logs of the information required to document compliance with the periodic kiln work practice standard.

• Records of burner tune-ups used to comply with the dioxin/furan work practice standard for tunnel kilns.

• Logs of the information required to document compliance with the startup and shutdown work practice standards.

• Records of each malfunction and the corrective action taken.

We are also proposing that the owner or operator submit the following reports and notifications:

• Notifications required by the General Provisions.

• Initial Notification no later than 120 calendar days after the affected source becomes subject to this subpart.

• Notification of Intent to conduct performance tests and/or other compliance demonstration at least 60 calendar days before the performance test and/or other compliance demonstration is scheduled.

• Notification of Compliance Status 60 calendar days following completion of a compliance demonstration that includes a performance test.

• Notification of Compliance Status 30 calendar days following completion of a

compliance demonstration that does not include a performance test (

i.e.,

compliance demonstrations for the work practice standards).

• Compliance reports semi-annually, including a report of the most recent burner tune-up conducted to comply with the dioxin/furan work practice standard and a report of each malfunction resulting in an exceedance and the corrective action taken.

• Results of each performance test within 60 days of completing the test, submitted to the EPA by direct computer-to-computer electronic transfer via EPA-provided software for data collected using supported test methods.

I. How would I submit emissions test results to the EPA?

In this proposal, the EPA is describing a process to increase the ease and efficiency of performance test data submittal while improving data accessibility. Specifically, the EPA is proposing that owners and operators of BSCP manufacturing facilities submit electronic copies of required performance test reports by direct computer-to-computer electronic transfer using EPA-provided software. The direct computer-to-computer electronic transfer is accomplished through the EPA's Central Data Exchange (CDX) using the Compliance and Emissions Data Reporting Interface (CEDRI). The CDX is the EPA's portal for submittal of electronic data. The EPA-provided software is called the Electronic Reporting Tool (ERT), which generates electronic reports of performance tests and evaluations. The ERT report package will be submitted using the CEDRI. The submitted report package will be stored in the CDX archive (the official copy of record) and the EPA's public database called WebFIRE. All stakeholders will have access to all reports and data in WebFIRE via the WebFIRE Report Search and Retrieval link (

http://cfpub.epa.gov/webfire/index.cfm?action=fire.searchERTSubmission

). A description and instructions for use of the ERT can be found on the ERT Web site (

http://www.epa.gov/ttn/chief/ert/index.html

), and CEDRI can be accessed through the CDX Web site (

www.epa.gov/cdx

The proposal to submit performance test data electronically to the EPA applies only to those performance tests conducted using test methods that are supported by the ERT at the time of the test. The ERT supports most of the commonly used EPA reference methods. A listing of the pollutants and test methods supported by the ERT is available on the ERT Web site.

We believe that the electronic submittal of reports increases the usefulness of the data contained in those reports, is in keeping with current trends in data availability and may ultimately result in less burden on the regulated community. Electronic reporting can eliminate paper-based, manual processes, thereby saving time and resources, simplifying data entry, eliminating redundancies and providing data quickly and accurately to the affected sources, air agencies, the EPA and the public.

By making data readily available, electronic reporting increases the amount of data that can be used for the development of emission factors. The EPA has received feedback from stakeholders asserting that many of the EPA's emission factors are outdated or not representative of a particular industry emission source. While the EPA believes that the emission factors are suitable for their intended purpose, we also recognize that emissions profiles on different pieces of equipment can change over time due to a number of factors (fuel changes, equipment improvements, industry work practices), and it is important for emission factors to be updated to keep up with these changes. The EPA is currently pursuing emission factor development improvements that include procedures to incorporate the source test data that we are proposing be submitted electronically.

Emission factors are used in the development of emissions inventories, and improved emission factors means that the quality of these inventories will be improved more quickly than they would under the current paper reporting requirements. Emissions inventories are used for tracking emission trends and identifying potential sources of emissions for reduction. For example, the EPA's National Air Toxics Assessment (NATA) uses the EPA's National Emissions Inventory (NEI) in its screening level assessments to characterize the nationwide chronic cancer risk estimates and noncancer hazards from inhaling air toxics. The NATA is used as a screening tool for air agencies to prioritize pollutants, emission sources and locations of interest for further study to gain a better understanding of risks. Therefore, improving the quality of these inventories is an on-going goal for the agency and a benefit to the public, air agencies and the regulated community.

Additionally, the EPA, the regulated community and the public may benefit from electronic reporting when the EPA conducts its CAA-required technology and risk-based reviews. Because we will already have access to these reports, our ability to do comprehensive reviews will be increased and achieved within a shorter period of time. Under an electronic reporting system, the EPA would have performance test data in hand; thus, it is possible that fewer or less substantial information collection requests (ICRs) in conjunction with prospective CAA-required technology and risk-based reviews may be needed. This may result in a decrease in the need for industry staff time to respond to data collection requests. It may also allow the EPA to conduct these required reviews more quickly, as we will not have to include the ICR collection time in the process. While the regulated community may benefit from reduced ICRs, the general public benefits from the agency's ability to conduct these required reviews more quickly.

Electronic reporting could minimize submission of unnecessary or duplicative reports in cases where facilities report to multiple government agencies and the agencies opt to rely on the EPA's electronic reporting system to view report submissions. Where air agencies continue to require a paper copy of these reports and will accept a hard copy of the electronic report, facilities will have the option to print paper copies of the electronic reporting forms to submit to the air agencies, thus minimizing the time spent reporting to multiple agencies. Additionally, maintenance and storage costs associated with retaining paper records could likewise be minimized by replacing those records with electronic records of electronically submitted data and reports.

There are benefits of information that is submitted in a standardized format. Standardizing the reporting format will require the reporting of specific data elements, thereby helping to ensure completeness of the data and allowing for accurate assessment of data quality. Additionally, imbedded quality assurance checks will perform some of the required method calculations, reducing errors in test reports. And because the system is entirely electronic, it eliminates transcription errors in moving data from paper reports to data systems for analysis. These quality assurance checks and procedures will increase the accuracy of test report data, improve the overall quality of test data, and lead to more accurate emission factors and higher quality emissions inventories. These features benefit all users of the data.

Air agencies could benefit from more streamlined and automated review of the electronically submitted data. For example, because the performance test data would be readily-available in a standard electronic format, air agencies

would be able to review reports and data electronically rather than having to conduct a review of the reports and data manually. Having reports and associated data in electronic format will facilitate review through the use of software “search” options, as well as the downloading and analyzing of data in spreadsheet format. Additionally, air agencies would benefit from the reported data being accessible to them through the EPA's electronic reporting system whenever they want or need access (as long as they have access to the Internet). The ability to access and review information electronically will assist air agencies in more quickly determining compliance with emission standards. This benefits both air agencies and the general public.

The general public would also benefit from electronic reporting of emissions data because the data would be available for viewing sooner and would be easier for the public to access. The EPA Web site that stores the submitted electronic data is easily accessible to the public and provides a user-friendly interface that any stakeholder could access.

In summary, in addition to supporting regulation development, control strategy development and other air pollution control activities, having an electronic database populated with performance test data would save industry, air agencies and the EPA significant time, money and effort while also improving the quality of emission inventories and air quality regulations.

IV. Rationale for the Proposed Rule for Brick and Structural Clay Products Manufacturing

A. How did the EPA determine which sources would be regulated under the proposed rule?

In the BSCP manufacturing industry, the primary sources of HAP emissions are kilns, including tunnel kilns and periodic kilns. The HAP emitted from BSCP kilns include HF, HCl, Cl

, Hg and other non-Hg HAP metals. At one time, dryers were a potential source of HF, HCl, Cl

and non-Hg HAP metals emissions, but the design and operation of kilns and dryers has changed such that emissions released from the heating of the raw materials and the products of combustion no longer pass from the kiln into the dryer. In addition, the 2010 EPA survey requested that owners/operators of specific dryers test for dioxins/furans, and none of the tests found detectable levels of dioxins/furans. See the technical memorandum “Determination of “Non-Detect” Test Data for the BSCP Proposed Rule” in Docket ID No. EPA-HQ-OAR-2013-0291. Other process units at BSCP manufacturing facilities (

e.g.,

raw material processing and handling) have not been found to emit measurable quantities of HAP. For this reason, the proposed rule covers existing and new kilns at major source BSCP manufacturing facilities which meet the applicability criteria in the rule.

BSCP kilns that do not meet the applicability criteria include kilns that are used exclusively for setting glazes on previously fired products. Nearly all of the acid gas emissions from the firing of BSCP products are released during the initial firing, so kilns that are used exclusively for setting glazes on previously fired products emit little to no HF, HCl or Cl

B. How did the EPA select the format for the proposed rule?

For Hg and total non-Hg HAP metals, this proposed BSCP manufacturing rule provides owners and operators of regulated sources with a choice between a numerical emission rate limit as a mass of pollutant emitted per ton of bricks produced and a numerical emission limit in units of concentration. The selection of numerical emission rate limits and numerical emission limits as the format for this proposed BSCP manufacturing rule provides flexibility for the regulated community by allowing a regulated source to choose any control technology or technique to meet the emission limits, rather than requiring each unit to use a prescribed control method that may not be appropriate in each case. In addition, the selection of numerical emission rate limits as mass of pollutant emitted per ton of bricks produced ensures that differences in kiln sizes or production rates do not affect the level of emissions control achieved.

The PM limits are proposed as a surrogate for non-Hg HAP metals. The same control techniques that would be used to control PM will control non-Hg HAP metals. Particulate matter was also chosen instead of requiring control of specific individual HAP metals because all kilns do not emit the same type and amount of HAP metals due to differences in raw materials and fuels used to fire the kilns. However, most kilns generally emit PM that includes some amount and combination of HAP metals. The use of PM as a surrogate will also eliminate the cost of performance testing needed to comply with numerous standards for individual non-Hg HAP metals. We have used PM as a surrogate for non-Hg HAP metals NESHAP for other rules with similar processes (

e.g.,

Portland Cement Manufacturing, Lime Manufacturing).

Although we continue to believe that PM is a good surrogate for non-Hg HAP metals and that complying with a PM emission limit rather than non-Hg HAP metals limits will be less costly for most kilns, we understand that some owners and operators may find that meeting a total non-Hg HAP metals limit is less costly than meeting a PM limit. To provide that flexibility, we have developed an alternative compliance option of a numerical emission rate limit for total non-Hg HAP metals as a mass of pollutant emitted per hour. The ability to comply with this limit would provide additional flexibility for small tunnel kilns and tunnel kilns with a low metals content in the PM emissions and would achieve equivalent emission reductions to the options to limit PM.

For acid gases (HF, HCl and Cl

), this proposed BSCP manufacturing rule includes a health-based emission limit as a mass of HCl-equivalent emitted per hour. Further discussion about the development of the health-based standard for the proposed BSCP manufacturing rule is provided in section IV.J of this preamble.

This proposed BSCP manufacturing rule includes work practices for dioxins/furans from tunnel kilns. As described in more detail in section IV.K.2 of this preamble, 83 percent of the dioxin/furan data collected during the ICR process were below the detection level and it is not practicable due to technological and economic limitations to apply measurement methodology to test for compliance with a numerical limit.

This proposed BSCP manufacturing rule also includes work practices for periodic kilns. As described in more detail in section IV.K.1 of this preamble, technological and economic limitations make it impracticable to measure compliance with numerical emission limits for BSCP periodic kilns.

C. How did the EPA consider different subcategories?

Section 112(d)(1) of the CAA allows the EPA to promulgate emission standards for either categories or subcategories of sources. Through subcategorization, we are able to define subsets of similar emission sources within a source category if differences in emissions characteristics, processes or opportunities for pollution prevention exist within the source category. Upon initial consideration of the available information on the BSCP manufacturing industry, we determined that separate subcategories for periodic kilns and tunnel kilns were warranted

for several reasons. First, periodic kilns are smaller than tunnel kilns (with lower production on an hourly basis, as well as accounting for only about 4 percent of total BSCP industry production). Second, periodic kilns are operated in batch cycles, whereas tunnel kilns operate continuously. Third, periodic kilns are typically operated at higher temperatures than tunnel kilns and products are typically heated in the kiln for longer periods than products fired in tunnel kilns, resulting in higher energy requirements. As noted in section IV.K.1 of this preamble, we have determined that it is technologically and economically infeasible to test periodic kilns, thereby ruling out a quantitative analysis of how these differences impact emissions. However, a qualitative comparison can be made, in that smaller kilns operated periodically (

i.e.,

periodic kilns) would be expected to have lower emissions over time compared to the larger, continuously operated tunnel kilns.

We then examined the potential for additional subcategories for tunnel kilns, including subcategorization based on kiln fuel and kiln size. Based on the available emissions test data, we could not discern differences in emissions based on fuel type. For that reason, we have not subcategorized by fuel type. We request comment, including additional data if appropriate, on whether we should subcategorize by fuel type. In particular, we request comment on whether we should create a subcategory for kilns fired with sawdust (with or without a sawdust dryer).

We then considered subcategorization of tunnel kilns based on kiln size. There are several differences between the design, operation and efficiency of larger kilns and smaller kilns. In particular, many small kilns are the older, less efficient kilns in the industry and newer kilns can be constructed to be larger and more efficient due to advances in design. Smaller, older kilns were constructed with large amounts of heavy refractory brick and are narrow and tall in shape, with high arched ceilings. Larger, newer kilns can be constructed with more efficient refractories and can include features such as fiber linings and insulating brick, resulting in a wider kiln with lower ceilings. In addition, the burners in a small kiln are generally less efficient and are located near the bottom of the kiln, where some of the heat is absorbed by the cars that move the bricks through the kiln rather than by the bricks themselves. In a large kiln, the burners are more efficient and are often located at the top of the kiln, where they can fire downward to the product. Combined with the kiln size and shape differences, the difference in burner efficiency and location results in a more even temperature distribution throughout the kiln and product in a large kiln than in a small kiln.

To assess whether these design and operation differences have an effect on emissions and provide support for defining size subcategories in the proposed BSCP manufacturing rule, we conducted a set of statistical analyses on the emissions dataset. In the vacated rule, “small kilns” were defined as kilns with a design capacity less than 10 tph and “large kilns” were defined as kilns with a design capacity of 10 tph or greater. The main goal of the statistical analyses was to determine if these definitions are supported by our current dataset. Because we have Cl

, Hg and non-Hg HAP metals data for only about 10 percent of the kilns in the industry, we conducted the series analyses based on the HF, HCl and PM datasets, which are available for a much larger percentage of the kilns in the industry, providing more representative kiln datasets for the analyses.

We found that the median of the emissions data from kilns in the large kiln dataset was statistically different than the median of the emissions data from kilns in the small kiln dataset for all three pollutants. Also, based on a logistic model, we found high association between emissions and the hypothesized design capacity classification. Finally, we conducted a cluster analysis and considered all three pollutants together to investigate whether the combined dataset supported changing the definitions of small and large kilns. This cluster analysis supported the subcategory definitions from the vacated rule. (For more information on the statistical analyses, see “Analysis of Potential Subcategories for BSCP Tunnel Kilns” in Docket ID No. EPA-HQ-OAR-2013-0291.)

Based on the above information and analyses, we determined that differences in design and emissions exist between large (10 tph or greater) and small (less than 10 tph) kilns. Therefore, we are proposing to exercise our discretion to subcategorize based on kiln size for these kilns' emissions of Hg. As discussed in section IV.D of this preamble, we are not proposing to exercise our discretion to subcategorize for other pollutants.

D. What approaches did the EPA consider in developing the proposed emission limitations for existing and new sources?

All standards established pursuant to CAA section 112(d)(2) must reflect MACT, the maximum degree of reduction in emissions of air pollutants that the Administrator, taking into consideration the cost of achieving such emissions reductions and any nonair quality health and environmental impacts and energy requirements, determined is achievable for each category.

For existing sources, MACT cannot be less stringent than the average emission limitation achieved by the best performing 12 percent of existing sources for categories and subcategories with 30 or more sources or the best performing five sources for subcategories with less than 30 sources. This requirement constitutes the MACT floor for existing sources. The CAA specifies that MACT for new sources shall not be less stringent than the emission control that is achieved in practice by the best controlled similar source. This minimum level of stringency is the MACT floor for new units.

The EPA may not consider costs or other impacts in determining the MACT floor. However, the EPA must consider cost, nonair quality health and environmental impacts and energy requirements in connection with any standards that are more stringent than the MACT floor (beyond-the-floor controls).

The remainder of this section describes the development of the pool of data used to calculate the MACT floors for Hg and PM (as a surrogate for non-Hg HAP metals). As noted in section IV.J of this preamble, health-based emissions standards are being proposed for the acid gases HF, HCl and Cl

under the provisions of CAA section 112(d)(4). Consequently, the EPA has not prepared a MACT floor analysis for these pollutants.

1. Mercury

In our MACT floor analysis for Hg, we separated the sources into large kiln and small kiln subcategories, as described in section IV.C of this preamble. For each subcategory, we ranked the sources based on the data in terms of lb/ton (as described in section IV.E of this preamble) and identified the best performing 12 percent of sources. Once we identified the best performing kilns, we then calculated the MACT floor in units of lb/ton for each subcategory as described in section IV.E of this

preamble. We also calculated the MACT floor in lb/hr and concentration units (μg/dscm at 7-percent O

) for each subcategory, based on the concentration emissions data for the same top 12 percent (best performing) sources as the lb/ton floor. This is further discussed in section IV.E of this preamble and in the technical memorandum “Maximum Achievable Control Technology (MACT) Floor Analysis for Brick and Structural Clay Products” in Docket ID No. EPA-HQ-OAR-2013-0291.

2. Total Non-Hg HAP Metals

We developed MACT floors for PM as a surrogate for total non-Hg HAP metals. The available PM data show that kilns controlled with a FF-based APCD (

e.g.,

DIFF, DLS/FF) as a group are better performers than kilns without FF-based controls. When we divided the kilns into two groups, one group consisting of kilns with a FF-based APCD and the other group consisting of uncontrolled kilns and kilns with a different type of APCD, we found that the test data for kilns with FF-based APCD showed they were consistently good performers, while the test data for kilns without a FF-based APCD varied widely. The worst performing kiln with a FF-based APCD performs better than the average kiln in the group without a FF-based APCD. The best performing 75 percent of the kilns with a FF-based APCD showed better performance than 80 percent of the kilns without a FF-based APCD. We also conducted a t-test on the averages of the two groups and we found that the average of the test data for kilns with FF-based APCD was statistically different from the average of the test data for kilns without a FF-based APCD (with 99-percent confidence). See the technical memorandum “Analysis of Potential Subcategories in the BSCP Source Category” in Docket ID No. EPA-HQ-OAR-2013-0291.

One consequence of the wide variability in emissions from kilns without a FF-based APCD is that there are a few uncontrolled kilns and kilns controlled with DLA with lower lb/ton emissions than some of the kilns controlled with a FF-based APCD. We understand that that the emissions from kilns with FF-based APCD will be consistently low over time, based on the design of these APCD and years of experience with these devices. On the other hand, we do not have multiple tests over time that would enable us to say the same for kilns that have a different type of APCD (

e.g.,

DLA) or are uncontrolled. Thus, we are requesting information and analysis as to whether the data showing low emissions from some kilns without a FF-based APCD are reliable.

Further, as discussed in section IV.P.1 of this preamble, the EPA is also considering setting emission limits for PM and total non-Hg HAP metals based on the top 12 percent of the data available in each of the kiln size subcategories. The reliability of the data showing low emissions from some kilns without a FF-based APCD is a key factor in the EPA's determination of which approach is appropriate.

As of January 1, 2014, there were 225 operating BSCP tunnel kilns in the industry (including kilns at major sources and synthetic area sources); the top 12 percent of the kilns in the industry would be represented by the 27 best performing kilns. Therefore, we ranked the kilns with a FF-based APCD in terms of lb/ton (as described in section IV.E of this preamble) and identified the 27 best performing sources from that group. Once we identified the best performing kilns, we then calculated the MACT floor in units of lb/ton as described in section IV.E of this preamble. We also calculated the MACT floor in concentration units (gr/dscf at 7-percent O

), based on the concentration emissions data for the same top 12 percent (best performing) sources as the lb/ton floor. As another alternative, we calculated an equivalent lb/hr total non-Hg HAP metals limit using the average non-Hg HAP metals content of the PM emissions and the average process rates of the best performing kilns. This limit would provide additional compliance flexibility for small tunnel kilns and tunnel kilns with a low metals content in the PM emissions. The alternatives are further discussed in section IV.E of this preamble and in the technical memorandum “Maximum Achievable Control Technology (MACT) Floor Analysis for Brick and Structural Clay Products” in Docket ID No. EPA-HQ-OAR-2013-0291.

E. How did the EPA determine the MACT floors for existing sources?

The EPA must consider available emissions information to determine the MACT floors. The EPA must exercise its judgment, based on an evaluation of the relevant factors and available data, to determine the level of emissions control that has been achieved by the best performing sources under variable conditions. The United States Court of Appeals for the District of Columbia Circuit has recognized that the EPA may consider variability in estimating the degree of emission reduction achieved by best performing sources and in setting MACT floors.

See Mossville Envt'l Action Now

EPA,

370 F.3d 1232, 1241-42 (D.C. Cir. 2004) (holding EPA may consider emission variability in estimating performance achieved by best performing sources and may set the floor at level that best performing source can expect to meet “every day and under all operating conditions”).

As discussed in section IV.D of this preamble, the EPA established the MACT floors for PM (as a surrogate for non-Hg HAP metals) for BSCP kilns based on sources representing 12 percent of the number of sources in the category. For Hg emitted from each of the kiln subcategories, the EPA established the MACT floors based on sources representing 12 percent of the sources for which we had emissions information. The MACT floor limitations for Hg and PM (as a surrogate for total non-Hg HAP metals) were calculated based on the performance of the best performing sources in each of the subcategories. The best performing sources were determined by ranking each source's average emission value from lowest to highest.

Once the best performing sources in the MACT floor pools were identified, the MACT floors were calculated using an Upper Prediction Limit (UPL). The UPL takes into consideration the average performance of the units in the MACT floor pool and the variability of the test runs during the testing conditions. For more information regarding the general use of the UPL and why it is appropriate for calculating MACT floors, see the memorandum “Use of the Upper Prediction Limit for Calculating MACT Floors” in Docket ID No. EPA-HQ-OAR-2013-0291.

The UPL represents the value which one can expect the mean of a specified number of future observations (

e.g.,

3-run average) to fall below for the specified level of confidence, based upon the results of an independent sample from the same population. A prediction interval for a future observation or an average of future observations, is an interval that will, with a specified degree of confidence, contain the next (or the average of some other pre-specified number of) randomly selected observation(s) from a population. Given this definition, the UPL represents the value which we can expect the mean of three future observations (3-run average) to fall below, based upon the results of an independent sample from the same population. In other words, if we were to randomly select a future test condition from any of these sources (

i.e.,

average of three runs), we can be 99 percent confident that the reported level will fall at or below the UPL value.

There are different UPL equations depending on the distribution of the data (

e.g.,

normal, lognormal, skewed/unknown). We first determined the distribution of each MACT floor pool's data to determine the appropriate UPL equation using statistical tests of the kurtosis (K), standard error of kurtosis (SEK), skewness (S) and standard error of skewness (SES). The skewness statistic (S) characterizes the degree of asymmetry of a given dataset. According to the skewness hypothesis test, if S is less than two times the SES, the data distribution can be considered to be normal. The kurtosis statistic (K) characterizes the degree of peakedness or flatness of a given data distribution in comparison to a normal distribution. According to the kurtosis hypothesis test, if K is less than two times the SEK, the data distribution can be considered to be normal. The skewness and kurtosis hypothesis tests were applied to both the reported test values and the log-transformed values of the reported test values to determine the distribution of each dataset. A UPL was then calculated for each MACT floor pool with the UPL equation corresponding to the dataset's distribution (

e.g.,

normal, lognormal, skewed/unknown).

A more detailed explanation of all the UPL equations used, including the calculations of kurtosis, standard error of kurtosis, skewness and standard error of skewness, can be found in the technical memorandum “Maximum Achievable Control Technology (MACT) Floor Analysis for Brick and Structural Clay Products” in Docket ID No. EPA-HQ-OAR-2013-0291.

Test method measurement imprecision can also be a component of data variability. Of particular concern are those data that are reported near or below a test method's pollutant detection capability. There is a concern that a floor emissions limit calculated using values at or near the method detection limit may not account adequately for data measurement variability. The expected measurement imprecision for an emissions value occurring at or near the detection limit is about 40 to 50 percent. Relative pollutant measurement imprecision decreases to a consistent 10 to 15 percent for values measured at a level about 3 times the method detection limit.

American Society of Mechanical Engineers,

Reference Method Accuracy and Precision (ReMAP): Phase 1, Precision of Manual Stack Emission Measurements,

CRTD Vol. 60, February 2001.

One approach that we believe could be applied to account for measurement variability would require defining a detection limit that is representative of the data used in establishing the floor emissions limitations and also minimizes the influence of an outlier test-specific method detection limit value. The EPA has developed a list of representative detection levels (RDL) developed from available pollutant specific method detection levels.

These RDL values are then multiplied by three to decrease measurement imprecision to around 10 to 15 percent (as noted in the previous paragraph), resulting in values referred to as “3×RDL” values.

“

Data and procedure for handling below detection level data in analyzing various pollutant emissions databases for MACT and RTR emissions limits.

” Memorandum from Peter Westlin, SPPD, MPG and Raymond Merrill, AQAD, MTG, to SPPD management and MACT rule writers. December 13, 2011.

The appropriate 3×RDL value was compared to the calculated UPL value for each pollutant and subcategory. If the 3×RDL value was less than the calculated UPL value, we concluded that measurement variability is adequately addressed and we used the calculated UPL value as the MACT floor emissions limit. If, on the other hand, the 3×RDL value was greater than the calculated UPL value, we concluded that the calculated UPL value does not account entirely for measurement variability. We then used the 3×RDL value in place of the calculated UPL value to ensure that measurement variability is adequately addressed in the MACT floor emissions limit. This check was part of the variability analysis for all existing MACT floors that had below detection limit (BDL) or detection level limited (DLL) run data present in the best performing datasets (see the technical memorandum “Maximum Achievable Control Technology (MACT) Floor Analysis for Brick and Structural Clay Products” in Docket ID No. EPA-HQ-OAR-2013-0291).

As previously discussed, we accounted for variability in setting floors, not only because variability is an element of performance, but because it is reasonable to assess best performance over time. For example, we know that the HAP emission data from the best performing units are, for the most part, short-term averages and that the actual HAP emissions from those sources will vary over time. If we do not account for this variability, we would expect that even the units that perform better than the floor on average could potentially exceed the floor emission levels a part of the time, which would mean that variability was not properly taken into account. This variability may include the day-to-day variability in the total HAP input to each unit; variability of the sampling and analysis methods; and variability resulting from site-to-site differences for the best performing units. The EPA's consideration of variability accounted for that variability exhibited by the data representing multiple units and multiple data values for a given unit (where available). We calculated the MACT floor based on the UPL (upper 99th percentile) as described earlier from the average performance of the best performing units and the variability of the best performing units.

We believe this approach reasonably ensures that the emission limits selected as the MACT floors adequately represent the level of emissions actually achieved by the average of the units in the top 12 percent, considering operational variability of those units. Both the analysis of the measured emissions from units representative of the top 12 percent and the variability analysis are reasonably designed to provide a meaningful estimate of the average performance or central tendency, of the best performing 12 percent of units in a given subcategory. A detailed discussion of the MACT floor methodology is presented in the technical memorandum “Maximum Achievable Control Technology (MACT) Floor Analysis for Brick and Structural Clay Products” in Docket ID No. EPA-HQ-OAR-2013-0291.

Table 5 of this preamble presents the average emission level of the best performing sources and the existing source MACT floor. For this source category, all the existing source MACT floors are based on the UPL.

Table 5—Summary of MACT Floor Results for Brick and Structural Clay Products Existing Sources

Subcategory

Parameter

b c

Large tunnel kilns (≥ 10 tph)

Avg. of best performing sources

1.6 E-05 lb/ton

1.7 E-04 lb/hr

14 μg/dscm

MACT floor

2.2 E-05 lb/ton

2.7 E-04 lb/hr

29 μg/dscm

Small tunnel kilns (< 10 tph)

Avg. of best performing sources

1.8 E-04 lb/ton

0.0010 lb/hr

62 μg/dscm

MACT floor

2.0 E-04 lb/ton

0.0011 lb/hr

70 μg/dscm

All kilns

Avg. of best performing sources

0.041 lb/ton.

0.011 gr/dscf.

MACT floor

0.16 lb/ton.

0.040 gr/dscf.

For this source category, all the existing source MACT floors are based on the UPL.

Concentration units are at 7-percent O

PM is a surrogate for non-Hg HAP metals.

F. How did the EPA determine the MACT floors for new sources?

The approach that we used to calculate the MACT floors for new sources is somewhat different from the approach that we used to calculate the MACT floors for existing sources because the statutory standard is different. Although the MACT floors for existing units are intended to reflect the performance achieved by the average of the best performing 12 percent of sources, the MACT floors for new units are meant to reflect the emission control that is achieved in practice by the best controlled similar source. Thus, for existing units, we are concerned about estimating the central tendency of a set of multiple units, whereas for new units, we are concerned about estimating the level of control that is representative of that achieved by a single best performing source. As with the analysis for existing sources, the new source analysis must account for variability.

Similar to the MACT floor process used for existing units, the approach we used for determining the MACT floor for new units was based on available emissions test data. Specifically, we calculated the new source MACT floor for a subcategory of sources by ranking each unit's average emission value within the subcategory from lowest to highest to identify the best performing similar source. The new source MACT floor limits for Hg and PM (as a surrogate for total non-Hg HAP metals) were calculated based on the performance of the best performing source for each pollutant in each of the subcategories.

The MACT floor limits for new sources were calculated using the same UPL formula as was used for existing sources, except the data used were from the best performing source rather than the best performing 12 percent of sources. As previously discussed, we accounted for variability of the best performing source in setting floors, not only because variability is an element of performance, but because it is reasonable to assess best performance over time. We calculated the new source MACT floor based on the UPL (upper 99th percentile) as described earlier from the average performance of the best performing similar source, Student's t-factor and the total variability of the best performing source.

This approach reasonably ensures that the emission limit selected as the MACT floor for new sources adequately represents the average level of control achieved in practice by the best controlled similar source, considering ordinary operational variability. A detailed discussion of the MACT floor methodology is presented in the technical memorandum “Maximum Achievable Control Technology (MACT) Floor Analysis for Brick and Structural Clay Products” in Docket ID No. EPA-HQ-OAR-2013-0291.

Table 6 of this preamble presents, for each subcategory and pollutant, the average emission level of the best performing similar source and the new source MACT floor. The new source MACT floors are based on the UPL unless otherwise noted.

Table 6—Summary of MACT Floor Results for Brick and Structural Clay Products New Sources

Subcategory

Parameter

b c

Large tunnel kilns (≥ 10 tph)

Avg. of top performer

1.5 E-05 lb/ton

1.8 E-04 lb/hr

10 μg/dscm

MACT floor

2.0 E-05 lb/ton

2.4 E-04 lb/hr

13 μg/dscm

Small tunnel kilns (< 10 tph)

Avg. of top performer

1.8 E-04 lb/ton

0.0010 lb/hr

62 μg/dscm

MACT floor

2.0 E-04 lb/ton

0.0011 lb/hr

70 μg/dscm

All kilns

Avg. of top performer

0.0060 lb/ton.

0.0020 gr/dscf.

MACT floor

0.022 lb/ton

0.0066 gr/dscf

The new source MACT floors are based on the UPL unless otherwise noted.

Concentration units are at 7 percent O

PM is a surrogate for non-Hg HAP metals.

The MACT floor is based on the 3×RDL value.

G. What is our approach for applying the upper prediction limit to limited datasets?

In a recent United States Court of Appeals for the District of Columbia Circuit decision in

National Association of Clean Water Agencies

EPA,

which involved challenges to EPA's MACT standards for sewage sludge incinerators, questions were raised regarding the application of the UPL to limited datasets. We have since addressed these questions, as explained in detail in the memorandum titled, “Approach for Applying the Upper Prediction Limit to Limited Datasets” (hereafter referred to as the “Limited Dataset Memo”), which is available in Docket ID No. EPA-HQ-OAR-2013-0291.

A limited dataset is defined as having less than seven data points. In calculating MACT floor limits based on limited datasets, we considered additional factors as described in the Limited Dataset Memo. We seek comments on the approach described in the Limited Dataset Memo and whether there are other approaches we should consider for such datasets. We also seek comments on the application of this approach for the derivation of MACT limits based on limited datasets in this proposal, which are described in the Limited Dataset Memo.

For the BSCP manufacturing source category, we have limited datasets for the following pollutants and subcategories: Hg for existing and new small tunnel kilns; PM for new tunnel kilns; and Hg for new large tunnel kilns. For each dataset, we performed the steps outlined in the Limited Dataset Memo. See the Limited Dataset Memo for more information.

H. How did the EPA consider beyond-the-floor for existing sources?

As discussed in sections II.A and IV.D of this preamble, the EPA must consider emissions limitations and requirements that are more stringent than the MACT floor (

i.e.,

beyond-the-floor options). When considering beyond-the-floor options, the EPA must consider not only the maximum degree of reduction in emissions of HAP, but must take into account the associated costs, energy and non-air quality health and environmental impacts.

Once the MACT floor determinations were complete for each subcategory, we considered regulatory options more stringent than the MACT floor level of control (

e.g.,

the performance of technologies that could result in lower emissions) for the different subcategories. We considered requiring all existing sources to meet the new source MACT floors for Hg and PM (as a surrogate for total non-Hg HAP metals) developed as described in section IV.F of this preamble. We analyzed the beyond-the-floor options for Hg and total non-Hg HAP metals separately for existing sources. Our analyses are documented in the technical memorandum, “Development of Cost and Emission Reduction Impacts for the BSCP NESHAP,” in Docket ID No. EPA-HQ-OAR-2013-0291.

The beyond-the-floor option for total non-Hg HAP metals is estimated to achieve additional non-Hg HAP metals reductions of 2.86 tpy and cost an additional $22.8 million per year (2011 dollars), for a cost effectiveness of $7,960,000 per ton of total additional non-Hg HAP metals removed. The beyond-the-floor option for Hg is estimated to achieve additional Hg reductions of 0.0625 tpy (125 pounds per year) and cost an additional $9.25 million per year (2011 dollars), for a cost effectiveness of $148,000,000 per ton of total additional Hg removed ($74,000 per pound of additional Hg removed). We have concluded that the incremental costs of additional control beyond the MACT floor emission limits are not reasonable relative to the level of emission reduction achieved for either the Hg or total non-Hg HAP metals beyond-the-floor options. Therefore, we are not proposing beyond-the-floor limits for Hg or total non-Hg HAP metals.

I. How did the EPA consider beyond-the-floor for new sources?

The MACT floor level of control for new tunnel kilns for each pollutant was based on the emission control that is achieved in practice by the best controlled similar source within each of the subcategories. A new kiln would likely need both a FF and ACI system for control of non-Hg HAP metals and Hg to meet the new source MACT floors. When we establish a beyond-the-floor standard, we typically identify control techniques that have the ability to achieve an emissions limit more stringent than the MACT floor. No techniques were identified that would achieve HAP reductions greater than the new source floors for the subcategories. Therefore, the EPA is not proposing a beyond-the-floor limit for new sources in this proposed BSCP manufacturing rule.

J. How did the EPA determine whether to set health-based standards for existing and new sources?

In developing the proposed BSCP manufacturing rule, we considered whether it was appropriate to establish health-based emission standards under CAA section 112(d)(4) for the acid gases HF, HCl and Cl

. As a general matter, CAA section 112(d) requires MACT standards at least as stringent as the MACT floor to be set for all HAP emitted from major sources. However, CAA section 112(d)(4) provides that for HAP with established health thresholds, the EPA has the discretionary authority to consider such health thresholds when establishing emission standards under CAA section 112(d). This provision is intended to allow the EPA to establish emission standards other than technology-based MACT standards, in cases where an alternative emission standard will still ensure that the health threshold will not be exceeded, with an ample margin of safety. This section discusses the prerequisite for setting a CAA section 112(d)(4) standard, the factors the EPA considered in exercising its discretion to set a CAA section 112(d)(4) standard and how the EPA set the level of the proposed standard.

1. What Are the Prerequisites for Setting a CAA Section 112(d)(4) Standard?

The prerequisites for setting a CAA section 112(d)(4) standard are that the pollutant must have a health threshold and not be carcinogenic.

Whether a pollutant has a health threshold is based on certain factors, including evidence and classification of carcinogenic risk and evidence of noncarcinogenic effects:

See

Portland Cement NESHAP Final Rule,

75 FR 54970, 54985 (col. 2-3) (September 9, 2010) (“In order to exercise this discretion [to set health threshold standards under 112(d)(4)], EPA must first conclude that the HAP at issue has an established health threshold . . .”).

See

Pulp and Paper Chemical Recovery Combustion Sources NESHAP Proposed Rule,

63 FR 18754, 18766/1-18767/1 (April 15, 1998).

• The EPA “presumptively concludes” that known, probable and possible carcinogens (Group A, B and C pollutants) “should not be categorized as threshold pollutants.”

• Pollutants for which there is not enough evidence to make a conclusion on carcinogenicity (Group D pollutants) will be evaluated on a case-by-case basis.

• Pollutants classified as non-carcinogens (Group E pollutants) are “presumptively considered” to be threshold pollutants.

The current weight-of-evidence under the 2005 EPA Guidelines for Carcinogen Risk Assessments, which replaced the 1986 cancer guidelines, recommends the following cancer hazard descriptors: “Carcinogenic to Humans,” “Likely to Be Carcinogenic to Humans,” “Suggestive Evidence of Carcinogenic Potential,” “Inadequate Information to Assess Carcinogenic Potential,” and “Not Likely to Be Carcinogenic to Humans” (which are considered equivalent to the 1986 groups A, B, C, D and E respectively).

Health threshold standards may not be set for pollutants that are carcinogenic.

See

Pulp and Paper Chemical Recovery Combustion Sources NESHAP Proposed Rule,

63 FR 18754, 18765/3 (“The EPA presumptively applies section 112(d)(4) only to HAP's that are not carcinogens because Congress clearly intended that carcinogens be considered nonthreshold pollutants”).

The EPA has exercised its discretionary authority under CAA section 112(d)(4) in a handful of prior actions setting emissions standards for other major source categories, including the emissions standards issued in 2004 for commercial and industrial boilers and process heaters, which were vacated on other grounds by the United States Court of Appeals for the District of Columbia Circuit. In the proposals for both the Pulp and Paper Chemical Recovery Combustion Sources NESHAP, 63 FR at 18765 (April 15, 1998) and Lime Manufacturing NESHAP, 67 FR at 78054 (December 20, 2002), the EPA invoked CAA section 112(d)(4) for HCl emissions for discrete units within the facility. In those proposed actions, the EPA concluded that HCl had an established health threshold (in those cases it was interpreted as the reference concentration for chronic effects or RfC) and was not classified as a human carcinogen. In light of the absence of evidence of carcinogenic risk, the availability of information on noncarcinogenic effects and the limited potential health risk associated with the discrete units being regulated, the EPA concluded that it was within the EPA's discretion to set an emissions standard under CAA section 112(d)(4) for HCl under the circumstances of those actions.

In more recent actions, the EPA noted that HCl was a threshold pollutant, but decided not to propose a health-based emission standard for HCl emissions under CAA section 112(d)(4) for Portland Cement facilities (74 FR at 21154; May 6, 2009) or for Boilers and Process Heaters (75 FR at 32032; June 4, 2010) for other reasons. To date, the EPA has not implemented a NESHAP that applied the provisions of CAA section 112(d)(4) to HF or Cl

The EPA has not classified HF or Cl

gas with respect to carcinogenicity. However, at this time the agency is not aware of any data that would suggest either of these HAP are carcinogens.

Since any emission standard under CAA section 112(d)(4) must consider the established health threshold level, with an ample margin of safety, in this proposed BSCP manufacturing rulemaking the EPA has considered the adverse health effects of the HAP acid gases, HCl, Cl

and HF. The standard approach for determining potential hazards of a pollutant has been to use a health benchmark below which effects are not expected to occur. Described below are the health effects and benchmarks for HCl, Cl

and HF and the rationale for their designation as threshold pollutants. It is important to note that if exposure levels as proposed by the emissions limits in this proposed BSCP manufacturing rulemaking are achieved, the adverse health effects described below will not be of concern for emissions from these source categories.

Hydrogen chloride is corrosive to the eyes, skin and mucous membranes. Acute inhalation exposure may cause eye, nose and respiratory tract irritation and inflammation and pulmonary edema in humans. Chronic occupational exposure to HCl has been reported to cause gastritis, bronchitis and dermatitis in workers. Prolonged exposure to low concentrations may also cause dental discoloration and erosion. No information is available on the reproductive or developmental effects of HCl in humans. In rats exposed to HCl by inhalation, altered estrus cycles have been reported in females and increased fetal mortality and decreased fetal weight have been reported in offspring. The EPA conducted a toxicity assessment of chronic inhalation exposure to HCl and has established an RfC of 20 micrograms per cubic meter (µg/m

An RfC is defined as an estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure to the human population (including sensitive subgroups

) that is likely to be without an appreciable risk of deleterious effects during a lifetime. The EPA RfC for HCl was based on respiratory toxicity observed in animals. An uncertainty factor of 300 was applied to the lowest adverse effect level noted in animals. This assessment did not take into account effects associated with acute exposure.

The EPA has not classified HCl for carcinogenicity.

U.S. Environmental Protection Agency.

Integrated Risk Information System (IRIS)

. Hydrogen chloride (CASRN 7647-01-0). 1995. Available at:

http://www.epa.gov/iris/subst/0396.htm

. Accessed on April 11, 2014.

“Sensitive subgroups” may refer to particular life stages, such as children or the elderly or to those with particular medical conditions, such as asthmatics.

California EPA considered acute toxicity and established a 1-hour reference exposure level (REL) of 2.1 mg/m

. An REL is the concentration level at or below which no adverse health effects are anticipated for a specified exposure duration. RELs are designed to protect the most sensitive individuals in the population by the inclusion of margins of safety.

With respect to the potential health effects of HCl, we know the following:

• Chronic exposure to concentrations at or below the RfC is not expected to cause chronic respiratory effects.

• Little research has been conducted on its carcinogenicity. The one occupational study of which we are aware found no evidence of carcinogenicity.

• There is a significant body of scientific literature addressing the health effects of acute exposure to HCl.

See California Office of Health Hazard Assessment.

Acute Toxicity Summary for Hydrogen Chloride.

Available at:

http://www.oehha.ca.gov/air/hot_spots/2008/AppendixD2_final.pdf#page=112

, EPA, 2008.

Based on this information, the agency believes it is reasonable to classify HCl as a Group D pollutant.

Based on the negative carcinogenicity data and on the EPA's knowledge of how HCl reacts in the body and its likely mechanism of action, as discussed above, the agency considers HCl to be a threshold pollutant.

See

Health Assessment Document for Chlorine and Hydrogen Chloride, Review Draft;

EPA-600/8-87/041A, August 1994.

The effects of acute exposure to humans and animals to Cl

have been well characterized. Similar to HCl, Cl

a well-known sensory irritant (capable of eliciting sensory irritation) and the most sensitive target for toxicity in humans and animals is the respiratory system. Acute exposures to low levels of Cl

(approximately 3 to 40 milligrams per cubic meter (mg/m

)) have been shown to cause nose, eyes and throat irritation in humans. Acute exposure to high levels (above 40 mg/m

) of Cl

in humans can result in chest pain, vomiting, toxic pneumonitis and pulmonary edema. Chronic (long-term) exposure to Cl

gas in workers has resulted in respiratory effects including eye and throat irritation and airflow obstruction. Animal studies have reported decreased body weight gain, eye and nose irritation, non-neoplastic nasal lesions and respiratory epithelial hyperplasia from chronic inhalation exposure to Cl

. There is no evidence that Cl

causes reproductive or developmental effects in animals or humans. A few studies of workers in the chemical industry did not find any evidence that Cl

is carcinogenic. The EPA, the International Agency for Research on Cancer (IARC) and the Department of Health and Human Services (DHHS) have not classified Cl

gas as to its carcinogenicity.

The human health value for Cl

is an Agency for Toxic Substances and Disease Registry (ATSDR) Minimal Risk Level (MRL) of 0.00015 µg/m

The MRL is defined as an estimate of daily human exposure to a substance that is likely to be without an appreciable risk of adverse effects (other than cancer) over a specified duration of exposure.

The MRL was based on respiratory toxicity (nasal lesions) observed in a chronic inhalation exposure (1 year) in monkeys. An uncertainty factor of 30 was applied to the MRL to account for uncertainties in extrapolating results from animal to humans and to account for human variability. Since the effects of acute exposure of humans and animals to Cl

have been well characterized, the ATSDR toxicity profile for Cl

also included acute MRL.

Toxicological Profile for Chlorine, Agency for Toxic Substances and Disease Registry (ATSDR) 2010. Available at

http://www.atsdr.cdc.gov/toxprofiles/tp.asp?id=1079&tid=36

Inhalation MRLs are used in noncancer assessments when IRIS RfCs are not available because their concept, definition and derivation are philosophically consistent (though not identical) with the basis for EPA's RfCs (

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

With respect to the potential health effects of Cl

, we know the following:

• Chronic exposure to concentrations at or below the MRL is not expected to cause chronic respiratory effects.

• The acute effects of Cl

have been well characterized in humans.

• Studies of workers in the chemical industry did not find any evidence that Cl

is carcinogenic.

Based on the negative carcinogenicity data and on the EPA's knowledge of how Cl

reacts in the body and its likely mechanism of action, as discussed above, the agency presumptively considers Cl

to be a threshold pollutant.

There is a significant body of scientific literature addressing the health effects of acute exposure to HF.

Hydrogen fluoride is a respiratory tract irritant capable of causing severe tissue damage in the respiratory system. Acute (short-term) inhalation exposure to gaseous HF can cause severe respiratory effects in humans, including severe irritation and pulmonary edema. Severe ocular irritation and dermal burns may occur following eye or skin exposure in humans. Because the toxic effects of HF are, to a large extent, based on the fluoride ion rather than the hydrogen ion, it is noteworthy to mention that the major health effect of chronic inhalation exposure to high levels of fluoride is skeletal fluorosis. In skeletal fluorosis, fluoride accumulates in the bone progressively over many years and can cause a variety of symptoms including stiffness and pain in the joints. In severe cases, the bone structure may change and ligaments may calcify, resulting in muscle impairment and pain. Chronic inhalation exposure to HF (with particulate fluorides) in the aluminum industry has been associated with increased risk of asthma. Chronic oral exposure to fluoride at low levels has a beneficial effect of dental cavity prevention and may also be useful for the treatment of osteoporosis. Exposure to higher levels of fluoride may cause dental and bone fluorosis. Although the existing toxicological database on fluoride does not provide strong evidence for the consideration of fluoride as an essential element, several organizations consider fluoride an important dietary element for humans. The Institute of Medicine (IOM) has derived adequate intake values ranging from 0.01 to 4 milligrams per day to reduce the occurrence of dental caries.

The World Health Organization (WHO) considers fluoride to be “essential” because it considered “resistance to dental caries to be a physiologically important function.”

With regard to HF carcinogenic potential, the ATSDR Public Health Statement document states that “carcinogenicity via inhalation of fluoride is not considered to be likely by most investigators reporting in the existing literature.” The EPA has not classified HF for carcinogenicity.

California EPA Chronic Toxicity Summary for Fluorides including Hydrogen Fluoride. 2003. Available at

http://www.oehha.org/air/hot_spots/2008/AppendixD3_final.pdf#page=270

IOM. 1997. Dietary reference intakes for calcium, phosphorus, magnesium, vitamin Dand fluoride. Washington, DC: Institute of Medicine. National Academy of Sciences. National Academy Press.

www4.nationalacademies.org/iom/iomhome.nsf

WHO. 2002. Fluorides. Geneva, Switzerland: World Health Organization. Environmental Health Criteria Number 227.

http://www.inchem.org/pages/ehc.html

The chronic inhalation noncancer human health value the EPA uses for HF is the REL of 0.014 mg/m

derived by California EPA (CalEPA).

CalEPA defines the REL as a concentration level at (or below) which no adverse health effects are anticipated for specific exposure durations, a concept that is substantially similar to EPA's non-cancer dose-response assessment perspective and we, therefore, use it as an alternate value in the absence of an IRIS RfC.

REL are designed to protect the most sensitive individuals in the population by the inclusion of margins of safety. The REL was based on minimal changes in bone density (skeletal fluorosis) in the workplace by Derryberry et al.

CalEPA states that major strengths of the key study on which the chronic REL is based is the observation of health effects in a large group of workers exposed over many years and the identification of no observable adverse effect level (NOAEL). The primary uncertainty in the study is the lack of comprehensive health effects examination. Another source of concern is the potential for greater susceptibility of children to the effects of inhaled fluorides, considering the rapid bone growth at early lifestages. This effect applies with particular importance to children's teeth since it has been established that excessive exposure to fluoride during tooth development in infancy and childhood causes dental fluorosis. To account for uncertainties, the CalEPA REL included a factor of 10 for intraspecies differences

(which also accounts for variation in kinetics between children and adults). In addition, the chronic inhalation REL is lower than the oral chronic REL and the California Public Health Guidance for fluoride in drinking water, which are based on lifetime exposure and protective of infants and children. CalEPA also considered the acute toxicity of HF and established a 1-hour REL of 0.24 mg/m

based on mild eye and respiratory irritation.

California EPA Chronic Toxicity Summary for Fluorides including Hydrogen Fluoride. 2003. Available at

http://www.oehha.org/air/hot_spots/2008/AppendixD3_final.pdf#page=270

The California Office of Environmental Health Hazard Assessment has developed dose-response assessments for many substances, based both on carcinogenicity and health effects other than cancer. The process for developing these assessments is similar to that used by the EPA to develop IRIS values and incorporates significant external scientific peer review. The EPA may use CalEPA values in the absence of an IRIS value.

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

Derryberry OM, Bartholomew MD, Fleming RBL. 1963. “Fluoride exposure and worker health.”

Arch Environ Health

6:503-514.

With respect to the potential health effects of HF, we know the following:

• Chronic exposure at or below the REL is not expected to cause adverse effects.

• There is limited/equivocal evidence of the carcinogenic potential of HF. With regard to the carcinogenic potential evidence available, the ATSDR Public Health Statement document on HF states that “carcinogenicity via inhalation of fluoride is not considered to be likely by most investigators reporting in the existing literature.”

Toxicological Profile for Chlorine, Agency for Toxic Substances and Disease Registry (ATSDR) 2010. Available at

http://www.atsdr.cdc.gov/toxprofiles/tp.asp?id=1079&tid=36

• There is significant evidence on the health effects of acute exposure to HF allowing for the derivation of an acute health benchmark.

Based on the negative carcinogenicity data and on the EPA's knowledge of how HF reacts in the body and its likely mechanism of action, as discussed above, the agency considers HF to be a threshold pollutant.

2. What factors does the EPA consider in exercising its discretion whether to set a CAA section 112(d)(4) standard?

The EPA may exercise its discretionary authority under CAA section 112(d)(4) only with respect to pollutants with a health threshold. Where there is an established threshold, the EPA interprets CAA section 112(d)(4) to allow it to weigh additional factors, beyond any established health threshold, in making a judgment whether to set a standard for a specific pollutant based on the threshold or instead follow the traditional path of developing a MACT standard after determining a MACT floor. In deciding whether to exercise its discretion for a threshold pollutant for a given source category, the EPA interprets CAA section 112(d)(4) to allow it to take into account factors such as the following:

• The availability of data to set the health-based standard;

• Co-benefits that would be achieved via the MACT standard, such as reductions in emissions of other HAP and/or criteria pollutants;

• The potential impacts on ecosystems of releases of the pollutant; and

• The potential for cumulative adverse health effects due to concurrent exposure to the same HAP or other HAP with similar biological endpoints, from either the same or other source categories, where the concentration of the threshold pollutant emitted from the given source category is below the threshold.

If the EPA does determine that it is appropriate to set a standard based on a health threshold, the agency must develop emission standards that will ensure the public will not be exposed to levels of the pertinent HAP emitted from the source category in question in excess of the health threshold, with an ample margin of safety.

a. Availability of Data To Determine a Standard

In determining whether to set a health-based standard, the EPA considered whether sufficient data for a particular industry are available to determine such a standard. In previous rules, the EPA declined to set a health-based standard, based in part on the unavailability of data to determine a standard.

However, for the proposed BSCP manufacturing rule, because of the relatively small number of facilities compared to other rules such as the Boiler MACT proposal, the EPA was able to determine facility-specific information, including tunnel kiln locations and operating characteristics and stack parameters, available for all BSCP facilities to assess the feasibility of health-based standards in this rule. Such information enabled us to conduct the dispersion modeling necessary to establish a health-based emission limit for acid gases.

Consequently, we have concluded that we have enough information to determine the health-based emission standards for the acid gases HF, HCl and Cl

for the BSCP manufacturing industry. As discussed in further detail below, these limits have been developed to ensure that exposure is below the health threshold for each facility and also ensure that acute exposures will not pose any health concerns.

See

Boiler MACT Proposed Rule,

75 FR 32006, 32031/3 (June 4, 2010) (“[W]e have concluded that we do not have sufficient information at this time to establish what the health-based emission standards would be for HCl or the other acid gases.”).

For more information, see the technical memorandum, “Risk Assessment to Determine a Health-Based Emission Limitation for Acid Gases for the Brick and Structural Clay Products Manufacturing Source Category,” in Docket ID No. EPA-HQ-OAR-2013-0291.

See

Portland Cement NESHAP Final Rule,

75 FR 54970, 54986/1 (September 9, 2010) (“[W]e currently lack information on the peak short-term emissions of HCl from cement kilns which might allow us to determine whether a chronic health-based emission standard for HCl would ensure that acute exposures will not pose health concerns.”).

b. Co-Benefits

We also considered whether setting technology-based MACT standards for HF, HCl and Cl

from BSCP plants would result in significant reductions in emissions of other pollutants, most notably sulfur dioxide (SO

). Although MACT standards may directly address only HAP, not criteria pollutants, Congress did recognize, in the legislative history to CAA section 112(d)(4), that MACT standards would have the collateral benefit of controlling criteria pollutants as well and viewed this as an important benefit of the air toxics program.

Therefore, even where the EPA concludes a HAP has a health threshold, the agency may consider such co-benefits as a factor in determining whether to exercise its discretion under CAA section 112(d)(4). The additional nationwide reductions of SO

that would be attributable to BSCP MACT standards for acid gases are estimated to be only 4,300 tpy in the third year following promulgation of the proposed BSCP standards. This reduction is substantially lower than the co-benefits from MACT standards for other industries for which the EPA has decided not to set a health-based limit,

and it would not be expected to provide a significant public health benefit.

See

S. Rep. No. 101-228, 101st Cong. 1st sess. at 172.

See

Portland Cement NESHAP Final Rule,

75 FR 54970 (September 9, 2010)—Co-benefits was identified as the “decisive factor” in the

Portland Cement NESHAP Final Rule

. 75 FR 54970, 54985/3. There, EPA declined to set a health-based standard for HCl where setting a MACT standard also controlled other HAP and criteria pollutants. Specifically discussed were SO

and other HAP gases. See 75 FR at 54984/3 (“The additional reductions of SO

alone attributable to the MACT standards for HCl are estimated to be 124,000 tons per year” and discussing both direct SO

effects and effects of SO

as a precursor to PM

2.5

) and 75 FR at 54986/1 (“[Other HAP gases (chlorine (Cl

), hydrogen cyanide (HCN) and hydrogen fluoride (HF))] are also controlled during the process of controlling HCl emissions from cement kilns using a wet scrubber. As such, their health impacts must be taken into account when considering a health-based emission limit for HCl.” See also

Boiler MACT Final Rule,

76 FR at 15644/1 (“EPA considered the comments received on this issue and continues to believe that the co-benefits are significant and provide an additional basis for the Administrator to conclude that it is not appropriate to exercise her discretion under section 112(d)(4).”) and

Boiler MACT Proposed Rule,

75 FR 32006, 32032 (June 4, 2010)—Co-benefits from MACT standard for HCl and PM as surrogate for HAP metals included the reduction of 340,000 tons per year of SO

and unspecified reductions of PM, other non-HAP acid gases (hydrogen bromide) and Hg. See also

MATS Proposed Rule,

76 FR 24976, 25051/1—Co-benefits from MACT standard for HCl and PM as surrogate for HAP metals included the reduction of 2.1 million tons per year of SO

and unspecified reductions of PM, other non-HAP acid gases (hydrogen bromide) and Hg.

c. Ecosystem Impacts

In addition to potential health impacts, the EPA has evaluated the potential for environmental impacts when considering whether to exercise discretion under CAA section 112(d)(4).

The agency applied the environmental risk screen methodology that it uses in the Risk and Technology Program under section 112 of the CAA to evaluate the potential for chronic exposure to acid gases emitted by BSCP facilities to cause phytotoxicity and reduced productivity of plants.

See

Portland Cement NESHAP Final Rule,

75 FR 54970, 54986/3 (September 9, 2010).

The environmental screen uses air concentrations from the HEM-3 model used in the human health exposure and risk analysis. We take these concentrations and derive an area-weighted average offsite annual ambient air concentration for each pollutant. The area-weighted average concentrations are compared directly to the appropriate ecological benchmarks for a given pollutant by dividing the area-weighted average concentration by the appropriate ecological benchmark. The result is called a hazard quotient (HQ). An HQ greater than 1 indicated that the area-weighted average concentration exceeded the ecological benchmark.

For the section 112(d)(4) evaluation, the EPA assessed the acid gases HCl and HF around each BSCP facility. Although Cl

may also be emitted from BSCP facilities, chlorine gas is so reactive that it is not expected to remain in the environment very long after it is released. Chlorine immediately reacts with both organic and inorganic materials that it comes into contact with. Chlorine undergoes direct photolysis in the air and its half-life in the troposphere is on the order of several minutes. Therefore, it was not considered in the environmental risk screening for the BSCP Manufacturing source category.

For HCl, the environmental risk screen indicated that the area-weighted average modeled concentrations of HCl around each facility (

i.e.,

the area-weighted average concentration of all offsite data points in the modeling domain) did not exceed the ecological benchmark. In addition, there was only one facility with a modeled concentration of HCl at an offsite receptor location that exceeded the ecological benchmark and that was at a single receptor.

For HF, the environmental risk screen indicated that the area-weighted average modeled concentrations of HF around each facility (

i.e.,

the area-weighted average concentration of all offsite data points in the modeling domain) did not exceed the ecological benchmarks. There were multiple facilities with modeled concentrations of HF at offsite receptor locations that exceeded the ecological benchmark, but the area over which the value was exceeded was less than one percent of the offsite modeling domain for each facility, indicating that there would not be any significant or widespread environmental effects.

d. Cumulative Effects

The EPA may consider the availability of information on emissions from co-located and nearby sources and consider if it is feasible to determine the potential cumulative health effects from emissions from the sources in the category when combined with other emissions from other sources that are co-located or located nearby. Relevant emissions may include both emissions of the same pollutant and emissions of other pollutants that may cause cumulative effects.

Through the BSCP industry's responses to the 2008 EPA survey and the 2010 EPA survey, we have substantial information on the locations of BSCP plants and the levels of HF, HCl and Cl

emitted from those plants. BSCP plants are not commonly co-located with any other type of operations. They are typically located near the source of the raw materials on large tracts of land from which raw materials are extracted. This provides an additional buffer between the BSCP plants and the surrounding area. Because of the relatively low plume heights, maximum risks from the BSCP plants are located close to the facility property line. In trying to define cumulative risks from nearby non-BSCP emissions, the location and emissions associated with other sources not in the BSCP Manufacturing source category are far less certain. While the EPA 2008 survey and EPA 2010 survey data for BSCP facilities have been reviewed by EPA engineers and scientists, the emissions levels and locations of nearby other facilities, such as those in the NEI, have not undergone the same level of detailed review. Thus, a quantitative analysis of nearby emissions may contain significant uncertainty. However, as discussed above, because of the large footprint of BSCP facilities, their rural locations and the BSCP risks being confined to the near plant locations, we do not expect that the combined emissions of HF, HCl or Cl

from BSCP facilities and nearby other sources would result in substantial cumulative health and environmental effects.

3. How did the EPA set the level of the standard?

Based on the EPA's findings, including the minimal cumulative health and environmental effects expected from co-located and nearby sources, the minimal co-benefits of setting technology-based MACT standards for acid gases, the minimal ecosystem impacts from setting a health-based standard in place of a MACT standard and the availability of data to determine a health-based standard, the EPA is proposing to exercise its discretion to use CAA section 112(d)(4). This conclusion is consistent with the EPA's prior decisions where we found it appropriate not to exercise the discretion to invoke the authority in CAA section 112(d)(4) for acid gases, because the circumstances in this case differ from those previous considerations. We request comment on the analysis and conclusions regarding setting health-based standards.

Following from the EPA's determination that a health-based standard is appropriate, the standard must be set as follows:

• There must be an ample margin of safety to avoid the health effects on which the threshold is based.

• There must be no observable adverse effect.

• The standard must not allow greater adverse environmental effects than the MACT standard that would otherwise be established.

• A standard must be set; there can be no exclusions from compliance based on a showing that the source's emissions do not pose a health risk.

CAA section 112(d)(4) expressly states that the health-based standard must be set at the threshold level “with an ample margin of safety.” In addition, the legislative history of CAA section 112(d)(4) indicates that a health-based emission limit under CAA section 112(d)(4) should be set at the level at which no observable effects occur, with an ample margin of safety.

Because the statute requires an ample margin of safety, it would be reasonable to set any CAA section 112(d)(4) emission standard for a pollutant with a health threshold at a level that at least assures that, for the sources in the controlled category or subcategory, persons exposed to emissions of the pollutant would not experience the adverse health effects on which the threshold is

based.

The legislative history also states that establishing a CAA section 112(d)(4) standard rather than a conventional MACT standard “shall not result in adverse environmental effects which would otherwise be reduced or eliminated.”

See

Boiler MACT Proposed Rule,

75 FR 32006, 32030/2 (June 4, 2010), citing S.Rep. 101-228 at 171-72.

See

Boiler MACT Proposed Rule,

75 FR 32006, 32031/3 (June 4, 2010).

See

Portland Cement NESHAP Final Rule,

75 FR 54970, 54985/2 (September 9, 2010), citing S.Rep. 101-228 at 171-72.

The EPA's decision to exercise its discretion to use CAA section 112(d)(4) will not be used to exclude sources from compliance. The EPA does not believe that a plain reading of the statute supports the establishment of an approach in which the EPA excludes specific facilities from complying with emissions limits if the facility demonstrates that its emissions do not pose a health risk. While CAA section 112(d)(4) authorizes the EPA to consider the level of the health threshold for pollutants which have an established threshold, that threshold may be considered when establishing emissions standards under CAA section 112(d). Therefore, the EPA must still establish emissions standards under CAA section 112(d) even if it chooses to exercise its discretion to consider an established health threshold.

See

Boiler MACT Final Rule,

76 FR 15608, 15643/3-14644/1 (March 21, 2011). See also

MATS Final Rule,

77 FR 9304, 9406/1 (February 16, 2012) (same point using nearly identical text).

As part of the development of the proposed standards, we have maintained an inventory of major source facilities, including the size and operating hours of each tunnel kiln and the geographic location and physical attributes (

e.g.,

stack height, diameter, exit gas flow rate) of each tunnel kiln stack. To develop a health-based emission limit, both long-term and short-term inhalation exposure concentrations and health risks from the BSCP manufacturing source category were estimated using the Human Exposure Model (Community and Sector HEM-3 version 1.3.1). The HEM-3 performs three primary risk assessment activities: (1) Conducting dispersion modeling to estimate the concentrations of HAP in ambient air, (2) estimating long-term and short-term inhalation exposures to individuals residing within 50 kilometers of the modeled sources and (3) estimating individual and population-level inhalation risks using the exposure estimates and quantitative dose-response information.

The air dispersion model used by the HEM-3 model (AERMOD) is one of the EPA's preferred models for assessing pollutant concentrations from industrial facilities. To perform the dispersion modeling and to develop the preliminary risk estimates, HEM-3 draws on three data libraries. The first is a library of meteorological data, which is used for dispersion calculations. This library includes one year (2011) of hourly surface and upper air observations for 824 meteorological stations, selected to provide coverage of the United States and Puerto Rico. A second library of United States Census Bureau census block internal point locations and populations provides the basis of human exposure calculations.

In addition, for each census block, the census library includes the elevation and controlling hill height, which are also used in dispersion calculations. A third library of pollutant unit risk factors and other health benchmarks is used to estimate health risks. These risk factors and health benchmarks are the latest values recommended by the EPA for HAP and other toxic air pollutants. The chronic and acute values for the acid gases evaluated in this assessment are presented in Tables 7 and 8 of this preamble, respectively. Further information on the development and sources of these benchmarks and the overall modeling approach is presented in the technical memorandum, “Risk Assessment to Determine a Health-Based Emission Limitation for Acid Gases for the Brick and Structural Clay Products Manufacturing Source Category” in Docket ID No. EPA-HQ-OAR-2013-0291.

USEPA Human Exposure Model; available at

http://www2.epa.gov/fera/download-human-exposure-model-hem

Table 7—Dose-Response Values for Chronic Inhalation Exposure to Acid Gases

Pollutant

CAS Number

RfC

(mg/m

)

Source

Hydrogen chloride

7647010

0.02

IRIS.

Hydrogen fluoride

7664393

0.014

CalEPA.

Chlorine

7782505

0.00015

ATSDR.

Chemical Abstract Services identification number. For groups of compounds that lack a CAS number, we have used a surrogate 3-digit identifier corresponding to the group's position on the CAA list of HAP.

Table 8—Dose-Response Values for Acute Inhalation Exposure to Acid Gases

Pollutant

CAS No.

AEGL-1

(1-hr)

(mg/m

)

AEGL-2

(1-hr)

(mg/m

)

ERPG-1

(mg/m

)

ERPG-2

(mg/m

)

REL

Hydrogen chloride

7647010

2.7

4.5

2.1

Hydrogen fluoride

7664393

0.82

1.6

0.24

Chlorine

7782505

1.5

5.8

2.9

8.7

0.21

AEGL = Acute Exposure Guideline Level, ERPG = Emergency Response Planning Guideline.

In developing the risk assessment for chronic exposures, we used the estimated annual average ambient air concentrations of each acid gas emitted by each source in the source category. The air concentrations at each nearby census block centroid were used as a surrogate for the chronic inhalation exposure concentration for all the people who reside in that census block. Chronic noncancer health hazards are expressed by comparing a chronic exposure to a reference level as a ratio. The HQ is the estimated exposure divided by a reference level (

e.g.,

the RfC). For a given acid gas, exposures at or below the reference level (HQ less than or equal to 1) are not likely to cause adverse health effects. As exposures increase above the reference level (HQs increasingly greater than 1),

the potential for adverse effects increases. For a typical risk assessment where multiple pollutants are co-emitted, we aggregate noncancer HQs of HAP that act by similar toxic modes of action or (where this information is absent) that affect the same target organ. This process creates, for each target organ, a specific hazard index (TOSHI) defined as the sum of HQs for individual HAP that affect the same organ or organ system. Because we performed HEM-3 model runs for each acid gas individually, we did not aggregate HQ values of different acid gases. Of course, multiple acid gas pollutants are emitted at BSCP facilities, but a 250 tpy level of HCl-equivalent emissions (based on the HEM risks modeling) ensures that a TOSHI of 1 is not exceeded as long as the HCl-equivalent emissions do not exceed 250 tpy. It is important to note that this emission limit is only applicable to the sources in this source category and should not be considered for sources other than those included in this analysis. Equivalent emissions for other acid gases are determined by the ratio of the chronic RfCs to that for HCl, such that the HCl-equivalent emissions for HF are 175 tpy and for Cl

are 1.9 tpy.

For the assessment of potential health risks from acute exposures to the acid gases, we performed a screening assessment using conservative assumptions that in combination approximate a worst-case exposure. The acute exposure scenario assumed worst-case meteorology (from one year of local meteorology) and that a person is located downwind at the point of maximum impact during this same worst-case 1-hour period, but no nearer to the source than 100 meters, which is conservative for this industry given our understanding of the locations of these facilities.

Screening for potentially significant acute inhalation exposures also followed the HQ approach. We divided the maximum estimated acute exposure by each available short-term threshold value to develop an array of HQ values relative to the various acute endpoints and thresholds. In general, when none of these HQ values are greater than 1, there is low potential for acute risk. In those cases where HQ values above 1 are seen, additional information is used to determine if there is a potential for significant acute risks. Additional information for facilities in the BSCP manufacturing source category included using aerial imagery of the facilities to determine the maximum offsite 1-hour concentrations.

Because the emissions equivalency was based on chronic dose-response values, the 250 tpy level does not necessarily ensure that acute reference levels will not be exceeded. For the HCl and Cl

model runs, there were no facilities with acute screening HQ values exceeding 1. For HF, we estimate that four of the 91 facilities examined had an acute value exceed the REL, with the highest being 2. However, no facility exceeded an HQ (AEGL-1) value for HF. To assure that no source emits more than the 250 tpy HCl-equivalent limit in a single hour, we propose setting the emissions limit at the hourly equivalent of 250 tpy (57 lb/hr of HCl-equivalent emissions).

It is important to note that the above emissions thresholds are developed from back-calculating the emissions that would result in an HQ of 1 at the worst-case facility. Potential risks at other facilities (not the worst-case facility) are predicted to be well below 1.

Because we had site-specific data on the operation of each tunnel kiln, we were able to use dispersion modeling to ensure that (1) the health-based emission limit cited above for BSCP facilities provides an ample margin of safety and (2) persons exposed to emissions of the pollutant would not experience the adverse health effects on which the threshold is based. In addition, as stated previously, the levels of acid gas emissions associated with BSCP kilns, based on results from the EPA's environmental risk screen methodology outlined above, are not expected to have an adverse environmental impact.

Facilities would demonstrate compliance with the health-based emission limit by determining their facility-wide HCl, HF and Cl

emissions, calculating the HCl-equivalent emissions for HF and Cl

using RfC values and adding the HCl emissions to the HCl-equivalent values to calculate the total HCl-equivalent emissions. An equation to perform this calculation is provided in the proposed BSCP manufacturing rule. For more information on the development of the health-based standard see the technical memorandum “Risk Assessment to Determine a Health-Based Emissions Limitation for Acid Gases for the Brick and Structural Clay Products Manufacturing Source Category” in Docket ID No. EPA-HQ-OAR-2013-0291. For more information on the calculation of an HCl-equivalent value, see the technical memorandum “Development of Cost and Emission Reduction Impacts for the BSCP NESHAP” in Docket ID No. EPA-HQ-OAR-2013-0291.

K. How did the EPA determine whether to set work practice standards for existing and new sources?

Under CAA section 112(h), the EPA may set work practice standards in place of an emissions standard where it is not feasible to prescribe or enforce an emission standard. The EPA is proposing to conclude that an emissions standard for certain HAP from certain BSCP manufacturing sources is not feasible because the application of measurement methodology to certain sources is not practicable due to technological and economic limitations. Specifically, the EPA is proposing a work practice standard for BSCP periodic kilns in lieu of emission limits for acid gases (HF, HCl and Cl

), Hg and non-Hg HAP metals. The EPA is also proposing a work practice standard for dioxin/furan emissions from BSCP tunnel kilns in lieu of a dioxin/furan emission limit. The rationale for these work practice standards is discussed in the paragraphs below. We request comment on how the work practice standards were developed and the proposed standards themselves.

1. Periodic Kilns

a. Rationale for Setting Work Practice Standard in Lieu of Emission Standard

Overview.

Periodic kilns are batch process units that are used for firing BSCP under a carefully controlled environment. The large majority of BSCP are fired in tunnel kilns, which operate continuously and are much more energy-efficient than periodic kilns when producing BSCP of a uniform type, such as standard building bricks. In contrast, periodic kilns can readily accommodate variations in firing temperature profiles and cycle time

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