Document ID: EPA-HQ-OAR-2010-0895-0144
Agency: epa
Document Type: Proposed Rule
Title: National Emission Standards for Hazardous Air Pollutants: Ferroalloys Production; Supplemental Notice of Proposed Rulemaking
Posted Date: 2014-10-06T04:00Z

[Federal Register Volume 79, Number 193 (Monday, October 6, 2014)]
[Proposed Rules]
[Pages 60237-60291]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-23266]

[[Page 60237]]

Vol. 79

Monday,

No. 193

October 6, 2014

Part II

Environmental Protection Agency

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40 CFR Part 63

 National Emission Standards for Hazardous Air Pollutants: Ferroalloys 
Production; Proposed Rule

  Federal Register / Vol. 79 , No. 193 / Monday, October 6, 2014 / 
Proposed Rules  

[[Page 60238]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2010-0895; FRL-9909-26-OAR]
RIN 2060-AQ11

National Emission Standards for Hazardous Air Pollutants: 
Ferroalloys Production

AGENCY: Environmental Protection Agency (EPA).

ACTION: Supplemental notice of proposed rulemaking.

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SUMMARY: This action supplements our proposed amendments to the 
national emission standards for hazardous air pollutants (NESHAP) for 
the Ferroalloys Production source category published in the Federal 
Register on November 23, 2011. In that action, the Environmental 
Protection Agency (EPA) proposed amendments based on the initial 
technology and residual risk reviews for this source category. Today's 
action presents a revised technology review and a revised residual risk 
review for the Ferroalloys Production source category and proposes 
revisions to the standards based on those reviews. This action also 
proposes new compliance requirements to meet the revised standards. 
This action would result in significant environmental improvements 
through the reduction of fugitive manganese emissions and through more 
stringent emission limits for several processes.

DATES: Comments. Comments must be received on or before November 20, 
2014. A copy of comments on the information collection provisions 
should be submitted to the Office of Management and Budget (OMB) on or 
before November 5, 2014.
    Public Hearing. If anyone contacts the EPA requesting a public 
hearing by October 14, 2014 the EPA will hold a public hearing on 
October 21, 2014 from 1:00 p.m. [Eastern Standard Time] to 8:00 p.m. 
[Eastern Standard Time] in Marietta, Ohio. 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-2010-0895, by one of the following methods:
     Federal eRulemaking Portal:
    http://www.regulations.gov. Follow the online instructions for 
submitting comments.
     Email: A-and-R-Docket@epa.gov. Include ``Attention Docket 
ID No. EPA-HQ-OAR-2010-0895'' in the subject line of the message.
     Fax: (202) 566-9744. Attention Docket ID Number EPA-HQ-
OAR-2010-0895.
     Mail: Environmental Protection Agency, EPA Docket Center 
(EPA/DC), Mail Code 28221T, Attention Docket ID No. EPA-HQ-OAR-2010-
0895, 1200 Pennsylvania Avenue NW., Washington, DC 20460. Please 
include a total of two copies. 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 Avenue NW., Washington, DC 20004, 
Attention Docket ID No. EPA-HQ-OAR-2010-0895. 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-
2010-0895. 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 
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 a docket for this rulemaking under 
Docket ID Number EPA-HQ-OAR-2010-0895. All documents in the docket 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, we will hold a public hearing on 
October 21, 2014, from 1:00 p.m. [Eastern Standard Time] to 8:00 p.m. 
[Eastern Standard Time] in Marietta, Ohio. There will be a dinner break 
from 5:00 p.m. [Eastern Standard Time] until 6:00 p.m. [Eastern 
Standard Time]. Please contact Ms. Virginia Hunt of the Sector Policies 
and Programs Division (E143-01), Office of Air Quality Planning and 
Standards, Environmental Protection Agency, Research Triangle Park, NC 
27711; telephone number: 919-541-0832; email address: 
hunt.virginia@epa.gov; to 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 October 20, 
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, please let us know at the time of registration. If you 
require an accommodation 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

[[Page 60239]]

action. The EPA will make every effort to accommodate all speakers who 
arrive and register.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Mr. Phil Mulrine, Sector Policies and Programs Division 
(D243-02), Office of Air Quality Planning and Standards, Environmental 
Protection Agency, Research Triangle Park, NC 27711; telephone (919) 
541-5289; fax number: (919) 541-3207; and email address: 
mulrine.phil@epa.gov. For specific information regarding the risk 
modeling methodology, contact Ms. Darcie Smith, Health and 
Environmental Impacts Division (C539-02), Office of Air Quality 
Planning and Standards, U.S. Environmental Protection Agency, Research 
Triangle Park, NC 27711; telephone number: (919) 541-2076; fax number: 
(919) 541-2076; and email address: smith.darcie@epa.gov. For 
information about the applicability of the National Emissions Standards 
for Hazardous Air Pollutants (NESHAP) to a particular entity, contact 
Cary Secrest, Office of Enforcement and Compliance Assurance (OECA), 
telephone number: (202) 564-8661 and email address: 
seacrest.cary@epa.gov.

SUPPLEMENTARY INFORMATION: 
Preamble Acronyms and Abbreviations
    We use multiple acronyms and terms in this preamble. 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:

AEGL--acute exposure guideline levels
AERMOD--air dispersion model used by the HEM-3 model
ATSDR--Agency for Toxic Substances and Disease Registry
BLDS--bag leak detection system
BTF--Beyond the Floor
CAA--Clean Air Act
CalEPA--California EPA
CBI--Confidential Business Information
CFR--Code of Federal Regulations
EJ--environmental justice
EPA--Environmental Protection Agency
ERPG--Emergency Response Planning Guidelines
ERT--Electronic Reporting Tool
FR--Federal Register
HAP--hazardous air pollutants
HCl--hydrochloric acid
HEM-3--Human Exposure Model, Version 1.1.0
HI--Hazard Index
HQ--Hazard Quotient
ICR--Information Collection Request
IRIS--Integrated Risk Information System
km--kilometer
LOAEL--lowest-observed-adverse-effect level
MACT--maximum achievable control technology
MACT Code--Code within the National Emissions Inventory used to 
identify processes included in a source category
mg/dscm--milligrams per dry standard cubic meter
mg/kg-day--milligrams per kilogram-day
mg/m\3\--milligrams per cubic meter
MIR--maximum individual risk
MRL--Minimal Risk Level
NAAQS--National Ambient Air Quality Standards
NAICS--North American Industry Classification System
NAS--National Academy of Sciences
NATA--National Air Toxics Assessment
NESHAP--National Emissions Standards for Hazardous Air Pollutants
NOAEL--no-observed-adverse-effect level
NRC--National Research Council
NTTAA--National Technology Transfer and Advancement Act
OAQPS--Office of Air Quality Planning and Standards
OECA--Office of Enforcement and Compliance Assurance
OMB--Office of Management and Budget
PAH--polycyclic aromatic hydrocarbons
PB-HAP--hazardous air pollutants known to be persistent and bio-
accumulative in the environment
PEL--probable effect level
PM--particulate matter
POM--polycyclic organic matter
ppm--parts per million
RDL--representative method detection level
REL--reference exposure level
RFA--Regulatory Flexibility Act
RfC--reference concentration
RfD--reference dose
RTR--residual risk and technology review
SAB--Science Advisory Board
SBA--Small Business Administration
SSM--startup, shutdown and malfunction
TOSHI--target organ-specific hazard index
TPY--tons per year
TRIM.FaTE--Total Risk Integrated Methodology.Fate, Transport, and 
Ecological Exposure model
TTN--Technology Transfer Network
UF--uncertainty factor
[micro]g/dscm--micrograms per dry standard cubic meter
[micro]g/m\3\--micrograms per cubic meter
UMRA--Unfunded Mandates Reform Act
UPL--Upper Prediction Limit
URE--unit risk estimate
VCS--voluntary consensus standards
    Organization of this Document. The information in this preamble is 
organized as follows:

I. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related 
information?
    C. What should I consider as I prepare my comments for the EPA?
II. Background Information
    A. What is the statutory authority for this action?
    B. What is this source category and how does the current NESHAP 
regulate its HAP emissions?
    C. What is the history of the Ferroalloys Production Risk and 
Technology Review?
    D. What data collection activities were conducted to support 
this action?
III. Analytical Procedures
    A. For purposes of this supplemental proposal, how did we 
estimate the post-MACT risks posed by the Ferroalloys Production 
Source Category?
    B. How did we consider the risk results in making decisions for 
this supplemental proposal?
    C. How did we perform the technology review?
IV. Revised Analytical Results and Proposed Decisions for the 
Ferroalloys Production Source Category
    A. What actions are we taking pursuant to CAA sections 112(d)(2) 
and 112(d)(3)?
    B. What are the results of the risk assessment and analyses?
    C. What are our proposed decisions regarding risk acceptability, 
ample margin of safety and adverse environmental effects based on 
our revised analyses?
    D. What are the results and proposed decisions based on our 
technology review?
    E. What other actions are we proposing?
    F. What compliance dates are we proposing?
V. Summary of the Revised Cost, Environmental and Economic Impacts
    A. What are the affected sources?
    B. What are the air quality impacts?
    C. What are the cost impacts?
    D. What are the economic impacts?
    E. What are the benefits?
VI. Request for Comments
VII. Submitting Data Corrections
VIII. 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. Does this action apply to me?

    Table 1 of this preamble lists the industrial source category that 
is the subject of this supplemental proposal. Table 1 is not intended 
to be exhaustive but rather to provide a guide for readers regarding 
the entities that this proposed action is likely to affect. The 
proposed standards, once finalized, will be

[[Page 60240]]

directly applicable to the affected sources. Federal, state, local and 
tribal government agencies are not affected by this proposed action. As 
defined in the ``Initial List of Categories of Sources Under Section 
112(c)(1) of the Clean Air Act Amendments of 1990'' (see 57 FR 31576, 
July 16, 1992), the ``Ferroalloys Production'' source category is any 
facility engaged in producing ferroalloys such as ferrosilicon, 
ferromanganese and ferrochrome.\1\ The EPA redefined the Ferroalloys 
Production source category when it promulgated the 1999 Ferroalloys 
Production standard so that it now includes only major sources that 
produce products containing manganese (Mn). (64 FR 27450, May 20, 
1999.) The 1999 standard applies specifically to two ferroalloy product 
types: Ferromanganese and silicomanganese.
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    \1\ U.S. EPA. Documentation for Developing the Initial Source 
Category List--Final Report, EPA/OAQPS, EPA-450/3-91-030, July, 
1992.

    Table 1--NESHAP And Industrial Source Categories Affected by This
                             Proposed Action
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         Source category                  NESHAP         NAICS code \a\
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Ferroalloys Production...........  Ferroalloys                    331110
                                    Production.
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\a\ 2012 North American Industry Classification System

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

    In addition to being available in the docket, an electronic copy of 
this action is available on the Internet through the EPA's Technology 
Transfer Network (TTN) Web site, a forum for information and technology 
exchange in various areas of air pollution control. Following signature 
by the EPA Administrator, the EPA will post a copy of this proposed 
action at: http://www.epa.gov/ttn/atw/ferropg.html. Following 
publication in the Federal Register, the EPA will post the Federal 
Register version of the proposal and key technical documents at this 
same Web site. Information on the overall residual risk and technology 
review program is available at the following Web site: http://www.epa.gov/ttn/atw/rrisk/rtrpg.html.

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

    Submitting CBI. Do not submit information containing CBI to the EPA 
through http://www.regulations.gov or email. Clearly mark the part or 
all of the information that you claim to be CBI. For CBI information on 
a disk or CD-ROM that you mail to the EPA, mark the outside of the disk 
or CD-ROM as CBI and then identify electronically within the disk or 
CD-ROM the specific information that is claimed as CBI. In addition to 
one complete version of the comments that includes information claimed 
as CBI, you must submit a copy of the comments that does not contain 
the information claimed as CBI for inclusion in the public docket. If 
you submit a CD-ROM or disk that does not contain CBI, mark the outside 
of the disk or CD-ROM clearly that it does not contain CBI. Information 
not marked as CBI will be included in the public docket and the EPA's 
electronic public docket without prior notice. Information marked as 
CBI will not be disclosed except in accordance with procedures set 
forth in 40 Code of Federal Regulations (CFR) part 2. Send or deliver 
information identified as CBI only to the following address: Roberto 
Morales, OAQPS Document Control Officer (C404-02), OAQPS, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711, Attention Docket ID Number EPA-HQ-OAR-2010-0895.

II. Background Information

A. What is the statutory authority for this action?

    Section 112 of the Clean Air Act (CAA) establishes a two-stage 
regulatory process to address emissions of hazardous air pollutants 
(HAP) from stationary sources. In the first stage, after the EPA has 
identified categories of sources emitting one or more of the HAP listed 
in CAA section 112(b), CAA section 112(d) requires us to promulgate 
technology-based NESHAP for those sources. ``Major sources'' are those 
that emit or have the potential to emit 10 tons per year (tpy) or more 
of a single HAP or 25 tpy or more of any combination of HAP. For major 
sources, the technology-based NESHAP must reflect the maximum degree of 
emission reductions of HAPs achievable (after considering cost, energy 
requirements and non-air quality health and environmental impacts) and 
are commonly referred to as maximum achievable control technology 
(MACT) standards.
    MACT standards must reflect the maximum degree of emissions 
reduction achievable through the application of measures, processes, 
methods, systems or techniques, including, but not limited to, measures 
that (1) reduce the volume of or eliminate pollutants through process 
changes, substitution of materials or other modifications; (2) enclose 
systems or processes to eliminate emissions; (3) capture or treat 
pollutants when released from a process, stack, storage or fugitive 
emissions point; (4) are design, equipment, work practice or 
operational standards (including requirements for operator training or 
certification); or (5) are a combination of the above. CAA section 
112(d)(2)(A)-(E). The MACT standards may take the form of design, 
equipment, work practice or operational standards where the EPA first 
determines either that (1) a pollutant cannot be emitted through a 
conveyance designed and constructed to emit or capture the pollutant, 
or that any requirement for, or use of, such a conveyance would be 
inconsistent with law; or (2) the application of measurement 
methodology to a particular class of sources is not practicable due to 
technological and economic limitations. CAA section 112(h)(1)-(2).
    The MACT ``floor'' is the minimum control level allowed for MACT 
standards promulgated under CAA section 112(d)(3) and may not be based 
on cost considerations. For new sources, the MACT floor cannot be less 
stringent than the emissions control that is achieved in practice by 
the best-controlled similar source. The MACT floor for existing sources 
can be less stringent than floors for new sources, but not less 
stringent than the average emissions limitation achieved by the best-
performing 12 percent of existing sources in the category or 
subcategory (or the best-performing five sources for categories or 
subcategories with fewer than 30 sources). In developing MACT 
standards, the EPA must also consider control options that are more 
stringent than the floor. We may establish standards more stringent 
than the floor based on considerations of the cost of achieving the 
emission reductions, any

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non-air quality health and environmental impacts and energy 
requirements.
    The EPA is then required to review these technology-based standards 
and revise them ``as necessary (taking into account developments in 
practices, processes, and control technologies)'' no less frequently 
than every eight years. CAA section 112(d)(6). In conducting this 
review, the EPA is not required to recalculate the MACT floor. Natural 
Resources Defense Council (NRDC) v. EPA, 529 F.3d 1077, 1084 (D.C. Cir. 
2008). Association of Battery Recyclers, Inc. v. EPA, 716 F.3d 667 
(D.C. Cir. 2013).
    The second stage in standard-setting focuses on reducing any 
remaining (i.e., ``residual'') risk according to CAA section 112(f). 
Section 112(f)(1) required that the EPA prepare a report to Congress 
discussing (among other things) methods of calculating the risks posed 
(or potentially posed) by sources after implementation of the MACT 
standards, the public health significance of those risks and the EPA's 
recommendations as to legislation regarding such remaining risk. The 
EPA prepared and submitted the Residual Risk Report to Congress, EPA-
453/R-99-001 (Risk Report) in March 1999. CAA section 112(f)(2) then 
provides that if Congress does not act on any recommendation in the 
Risk Report, the EPA must analyze and address residual risk for each 
category or subcategory of sources 8 years after promulgation of such 
standards pursuant to CAA section 112(d).
    Section 112(f)(2) of the CAA requires the EPA to determine for 
source categories subject to MACT standards whether the emission 
standards provide an ample margin of safety to protect public health. 
Section 112(f)(2)(B) of the CAA expressly preserves the EPA's use of 
the two-step process for developing standards to address any residual 
risk and the agency's interpretation of ``ample margin of safety'' 
developed in the National Emissions Standards for Hazardous Air 
Pollutants: Benzene Emissions From Maleic Anhydride Plants, 
Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene Equipment 
Leaks, and Coke By-Product Recovery Plants (Benzene NESHAP) (54 FR 
38044, September 14, 1989). The EPA notified Congress in the Risk 
Report that the agency intended to use the Benzene NESHAP approach in 
making CAA section 112(f) residual risk determinations (EPA-453/R-99-
001, p. ES-11). The EPA subsequently adopted this approach in its 
residual risk determinations and in a challenge to the risk review for 
the Synthetic Organic Chemical Manufacturing source category, the 
United States Court of Appeals for the District of Columbia Circuit 
upheld as reasonable the EPA's interpretation that subsection 112(f)(2) 
incorporates the approach established in the Benzene NESHAP. See NRDC 
v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 2008) (``[S]ubsection 
112(f)(2)(B) expressly incorporates the EPA's interpretation of the 
Clean Air Act from the Benzene standard, complete with a citation to 
the Federal Register.''); see also A Legislative History of the Clean 
Air Act Amendments of 1990, vol. 1, p. 877 (Senate debate on Conference 
Report).
    The first step in the process of evaluating residual risk is the 
determination of acceptable risk. If risks are unacceptable, the EPA 
cannot consider cost in identifying the emissions standards necessary 
to bring risks to an acceptable level. The second step is the 
determination of whether standards must be further revised in order to 
provide an ample margin of safety to protect public health. The ample 
margin of safety is the level at which the standards must be set, 
unless an even more stringent standard is necessary to prevent, taking 
into consideration costs, energy, safety and other relevant factors, an 
adverse environmental effect.
1. Step 1--Determination of Acceptability
    The agency in the Benzene NESHAP concluded that ``the acceptability 
of risk under section 112 is best judged on the basis of a broad set of 
health risk measures and information'' and that the ``judgment on 
acceptability cannot be reduced to any single factor.'' Benzene NESHAP 
at 38046. The determination of what represents an ``acceptable'' risk 
is based on a judgment of ``what risks are acceptable in the world in 
which we live'' (Risk Report at 178, quoting NRDC v. EPA, 824 F. 2d 
1146, 1165 (D.C. Cir. 1987) (en banc) (``Vinyl Chloride''), recognizing 
that our world is not risk-free.
    In the Benzene NESHAP, we stated that ``EPA will generally presume 
that if the risk to [the maximum exposed] individual is no higher than 
approximately one in 10 thousand, that risk level is considered 
acceptable.'' 54 FR at 38045, September 14, 1989. We discussed the 
maximum individual lifetime cancer risk (or maximum individual risk 
(MIR)) as being ``the estimated risk that a person living near a plant 
would have if he or she were exposed to the maximum pollutant 
concentrations for 70 years.'' Id. We explained that this measure of 
risk ``is an estimate of the upper bound of risk based on conservative 
assumptions, such as continuous exposure for 24 hours per day for 70 
years.'' Id. We acknowledged that maximum individual lifetime cancer 
risk ``does not necessarily reflect the true risk, but displays a 
conservative risk level which is an upper-bound that is unlikely to be 
exceeded.'' Id.
    Understanding that there are both benefits and limitations to using 
the MIR as a metric for determining acceptability, we acknowledged in 
the Benzene NESHAP that ``consideration of maximum individual risk * * 
* must take into account the strengths and weaknesses of this measure 
of risk.'' Id. Consequently, the presumptive risk level of 100-in-1 
million (1-in-10 thousand) provides a benchmark for judging the 
acceptability of maximum individual lifetime cancer risk, but does not 
constitute a rigid line for making that determination. Further, in the 
Benzene NESHAP, we noted that:

[p]articular attention will also be accorded to the weight of 
evidence presented in the risk assessment of potential 
carcinogenicity or other health effects of a pollutant. While the 
same numerical risk may be estimated for an exposure to a pollutant 
judged to be a known human carcinogen, and to a pollutant considered 
a possible human carcinogen based on limited animal test data, the 
same weight cannot be accorded to both estimates. In considering the 
potential public health effects of the two pollutants, the Agency's 
judgment on acceptability, including the MIR, will be influenced by 
the greater weight of evidence for the known human carcinogen.

Id. at 38046. The agency also explained in the Benzene NESHAP that:

[i]n establishing a presumption for MIR, rather than a rigid line 
for acceptability, the Agency intends to weigh it with a series of 
other health measures and factors. These include the overall 
incidence of cancer or other serious health effects within the 
exposed population, the numbers of persons exposed within each 
individual lifetime risk range and associated incidence within, 
typically, a 50 km exposure radius around facilities, the science 
policy assumptions and estimation uncertainties associated with the 
risk measures, weight of the scientific evidence for human health 
effects, other quantified or unquantified health effects, effects 
due to co-location of facilities, and co-emission of pollutants.

Id. at 38045. In some cases, these health measures and factors taken 
together may provide a more realistic description of the magnitude of 
risk in the exposed population than that provided by maximum individual 
lifetime cancer risk alone.
    As noted earlier, in NRDC v. EPA, the court held that section 
112(f)(2)

[[Page 60242]]

``incorporates the EPA's interpretation of the Clean Air Act from the 
Benzene Standard.'' The court further held that Congress' incorporation 
of the Benzene standard applies equally to carcinogens and non-
carcinogens. 529 F.3d at 1081-82. Accordingly, we also consider non-
cancer risk metrics in our determination of risk acceptability and 
ample margin of safety.
2. Step 2--Determination of Ample Margin of Safety
    CAA section 112(f)(2) requires the EPA to determine, for source 
categories subject to MACT standards, whether those standards provide 
an ample margin of safety to protect public health. As explained in the 
Benzene NESHAP, ``the second step of the inquiry, determining an `ample 
margin of safety,' again includes consideration of all of the health 
factors, and whether to reduce the risks even further. . . . Beyond 
that information, additional factors relating to the appropriate level 
of control will also be considered, including costs and economic 
impacts of controls, technological feasibility, uncertainties and any 
other relevant factors. Considering all of these factors, the agency 
will establish the standard at a level that provides an ample margin of 
safety to protect the public health, as required by section 112.'' 54 
FR at 38046, September 14, 1989.
    According to CAA section 112(f)(2)(A), if the MACT standards for 
HAP ``classified as a known, probable, or possible human carcinogen do 
not reduce lifetime excess cancer risks to the individual most exposed 
to emissions from a source in the category or subcategory to less than 
one in one million,'' the EPA must promulgate residual risk standards 
for the source category (or subcategory), as necessary to provide an 
ample margin of safety to protect public health. In doing so, the EPA 
may adopt standards equal to existing MACT standards if the EPA 
determines that the existing standards (i.e., the MACT standards) are 
sufficiently protective. NRDC v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 
2008) (``If EPA determines that the existing technology-based standards 
provide an `ample margin of safety,' then the Agency is free to readopt 
those standards during the residual risk rulemaking.'') The EPA must 
also adopt more stringent standards, if necessary, to prevent an 
adverse environmental effect,\2\ but must consider cost, energy, safety 
and other relevant factors in doing so.
---------------------------------------------------------------------------

    \2\ ``Adverse environmental effect'' is defined as any 
significant and widespread adverse effect, which may be reasonably 
anticipated to wildlife, aquatic life or natural resources, 
including adverse impacts on populations of endangered or threatened 
species or significant degradation of environmental qualities over 
broad areas. CAA section 112(a)(7).
---------------------------------------------------------------------------

    The CAA does not specifically define the terms ``individual most 
exposed,'' ``acceptable level'' and ``ample margin of safety.'' In the 
Benzene NESHAP, 54 FR at 38044-38045, September 14, 1989, we stated as 
an overall objective:

    In protecting public health with an ample margin of safety under 
section 112, EPA strives to provide maximum feasible protection 
against risks to health from hazardous air pollutants by (1) 
protecting the greatest number of persons possible to an individual 
lifetime risk level no higher than approximately 1-in-1 million and 
(2) limiting to no higher than approximately 1-in-10 thousand [i.e., 
100-in-1 million] the estimated risk that a person living near a 
plant would have if he or she were exposed to the maximum pollutant 
concentrations for 70 years.

The agency further stated that ``[t]he EPA also considers incidence 
(the number of persons estimated to suffer cancer or other serious 
health effects as a result of exposure to a pollutant) to be an 
important measure of the health risk to the exposed population. 
Incidence measures the extent of health risks to the exposed population 
as a whole, by providing an estimate of the occurrence of cancer or 
other serious health effects in the exposed population.'' Id. at 38045.
    In the ample margin of safety decision process, the agency again 
considers all of the health risks and other health information 
considered in the first step, including the incremental risk reduction 
associated with standards more stringent than the MACT standard or a 
more stringent standard that EPA has determined is necessary to ensure 
risk is acceptable. In the ample margin of safety analysis, the agency 
considers additional factors, including costs and economic impacts of 
controls, technological feasibility, uncertainties and any other 
relevant factors. Considering all of these factors, the agency will 
establish the standard at a level that provides an ample margin of 
safety to protect the public health, as required by CAA section 112(f). 
54 FR 38046, September 14, 1989.

B. What is this source category and how does the current NESHAP 
regulate its HAP emissions?

    Ferroalloys are alloys of iron in which one or more chemical 
elements (such as chromium, manganese and silicon) are added into 
molten metal. Ferroalloys are consumed primarily in iron and steel 
making and are used to produce steel and cast iron products with 
enhanced or special properties. The ferroalloys products that are the 
focus of the NESHAP are ferromanganese (FeMn) and silicomanganese 
(SiMn), which are produced by two facilities in the United States. One 
facility (Eramet) is located in Marietta, Ohio and produces both FeMn 
and SiMn. The other plant (Felman) is located in Letart, West Virginia 
and produces only SiMn.
    Ferroalloys within the scope of this source category are produced 
using submerged electric arc furnaces, which are furnaces in which the 
electrodes are submerged into the charge. The submerged arc process is 
a reduction smelting operation. The reactants consist of metallic ores 
(ferrous oxides, silicon oxides, manganese oxides, etc.) and a carbon-
source reducing agent, usually in the form of coke, charcoal, high- and 
low-volatility coal, or wood chips. Raw materials are crushed and sized 
and then conveyed to a mix house for weighing and blending. Conveyors, 
buckets, skip hoists or cars transport the processed material to 
hoppers above the furnace. The mix is gravity-fed through a feed chute 
either continuously or intermittently, as needed. At high temperatures 
in the reaction zone, the carbon source reacts with metal oxides to 
form carbon monoxide and to reduce the ores to base metal.\3\ The 
molten material (product and slag) is tapped from the furnace, 
sometimes subject to post-furnace refining and poured into casting beds 
on the furnace room floor. Once the material hardens, it is transported 
to product crushing and sizing systems and packaged for transport to 
the customer.
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    \3\ EPA. AP-42, 12.4. Ferroalloy Production. 10/86.
---------------------------------------------------------------------------

    The NESHAP for Ferroalloys Production: Ferromanganese and 
Silicomanganese were promulgated on May 20, 1999 (64 FR 27450) and 
codified at 40 CFR part 63, subpart XXX.\4\ The 1999 NESHAP applies to 
all new and existing ferroalloys production facilities that manufacture 
ferromanganese or silicomanganese and are major sources or are co-
located at major sources of HAP emissions.
---------------------------------------------------------------------------

    \4\ The emission limits were revised on March 22, 2001 (66 FR 
16024) in response to a petition for reconsideration submitted to 
the EPA following promulgation of the final rule and a petition for 
review filed in the U.S. Court of Appeals for the District of 
Columbia Circuit.
---------------------------------------------------------------------------

    The existing Ferroalloys Production NESHAP rule applies to process 
emissions from the submerged arc furnaces, the metal oxygen refining 
process and the product crushing equipment; process fugitive emissions 
from the furnace; and outdoor fugitive dust emissions sources such as

[[Page 60243]]

roadways, yard areas and outdoor material storage and transfer 
operations. For the electric (submerged) arc furnace process, the 
NESHAP specifies numerical emissions limits for particulate matter (as 
a surrogate for non-mercury (or particulate) metal HAP). The NESHAP 
also includes emissions limits for particulate matter (again as a 
surrogate for particulate metal HAP) for process emissions from the 
metal oxygen refining process and product crushing and screening 
equipment. Table 2 is a summary of the applicable limits in the 
existing Subpart XXX.

                                     Table 2--Emission Limits in Subpart XXX
----------------------------------------------------------------------------------------------------------------
   New or reconstructed or existing                              Applicable PM emission
                source                     Affected source             standards          Subpart XXX reference
----------------------------------------------------------------------------------------------------------------
New or reconstructed.................  Submerged arc furnace..  0.23 kilograms per hour  40 CFR 63.1652(a)(1)
                                                                 per megawatt (kg/hr/     and (a)(2)
                                                                 MW) (0.51 pounds per
                                                                 hour per megawatt (lb/
                                                                 hr/MW) or 35
                                                                 milligrams per dry
                                                                 standard cubic meter
                                                                 (mg/dscm) (0.015
                                                                 grains per dry
                                                                 standard cubic foot
                                                                 (gr/dscf).
Existing.............................  Open submerged arc       9.8 kg/hr (21.7 lb/hr).  40 CFR 63.1652(b)(1)
                                        furnace producing
                                        ferromanganese and
                                        operating at a furnace
                                        power input of 22
                                        megawatts (MW) or less.
Existing.............................  Open submerged arc       13.5 kg/hr (29.8 lb/hr)  40 CFR 63.1652(b)(2)
                                        furnace producing
                                        ferromanganese and
                                        operating at a furnace
                                        power input greater
                                        than 22 MW.
Existing.............................  Open submerged arc       16.3 kg/hr (35.9 lb/hr)  40 CFR 63.1652(b)(3)
                                        furnace producing
                                        silicomanganese and
                                        operating at a furnace
                                        power input greater
                                        than 25 MW.
Existing.............................  Open submerged arc       12.3 kg/hr (27.2 lb/hr)  40 CFR 63.1652(b)(4)
                                        furnace producing
                                        silicomanganese and
                                        operating at a furnace
                                        power input of 25 MW
                                        or less.
Existing.............................  Semi-sealed submerged    11.2 kg/hr (24.7 lb/hr)  40 CFR 63.1652(c)
                                        arc furnace (primary,
                                        tapping and vent
                                        stacks) producing
                                        ferromanganese.
New, reconstructed, or existing......  Metal oxygen refining    69 mg/dscm (0.03 gr/     40 CFR 63.1652(d)
                                        process.                 dscf).
New or reconstructed.................  Individual equipment     50 mg/dscm (0.022 gr/    40 CFR 63.1652(e)(1)
                                        associated with the      dscf).
                                        product crushing and
                                        screening operation.
Existing.............................  Individual equipment     69 mg/dscm (0.03 gr/     40 CFR 63.1652(e)(2)
                                        associated with the      dscf).
                                        product crushing and
                                        screening operation.
----------------------------------------------------------------------------------------------------------------

    The 1999 NESHAP established a building opacity limit of 20 percent 
that is measured during the required furnace control device performance 
test. The rule provides an excursion limit of 60 percent opacity for 
one 6-minute period during the performance test. The opacity 
observation is focused only on emissions exiting the shop due solely to 
operations of any affected submerged arc furnace. In addition, blowing 
taps, poling and oxygen lancing of the tap hole, burndowns associated 
with electrode measurements and maintenance activities associated with 
submerged arc furnaces and casting operations are exempt from the 
opacity standards specified in Sec.  63.1653.
    For outdoor fugitive dust sources, as defined in Sec.  63.1652, the 
1999 NESHAP requires that plants prepare and operate according to an 
outdoor fugitive dust control plan that describes in detail the 
measures that will be put in place to control outdoor fugitive dust 
emissions from the individual outdoor fugitive dust sources at the 
facility. The owner or operator must submit a copy of the outdoor 
fugitive dust control plan to the designated permitting authority on or 
before the applicable compliance date.

C. What is the history of the Ferroalloys Production Risk and 
Technology Review?

    Pursuant to section 112(f)(2) of the CAA, we first evaluated the 
residual risk associated with the Ferroalloys Production NESHAP in 
2011. We also conducted a technology review, as required by section 
112(d)(6) of the CAA. Finally, we also reviewed the 1999 MACT rule to 
determine if other amendments were appropriate. Based on the results of 
that previous residual risk and technology review (RTR) and the MACT 
rule review, we proposed amendments to subpart XXX on November 23, 2011 
(76 FR 72508) (referred to from here on as the 2011 proposal in the 
remainder of this FR notice). The proposed amendments in the 2011 
proposal which we are revisiting in today's supplemental proposal 
include the following:
     Revisions to particulate matter (PM) standards for 
electric arc furnaces and local ventilation control devices;
     emission limits for mercury, polycyclic aromatic 
hydrocarbons (PAHs), and hydrochloric acid (HCl);
     proposed requirements to control process fugitive 
emissions based on full-building enclosure with negative pressure, or 
fenceline monitoring as an alternative;
     a provision for emissions averaging;
     amendments to the monitoring, notification, recordkeeping 
and testing requirements; and
     proposed provisions establishing an affirmative defense to 
civil penalties for violations caused by malfunctions.
    The comment period for the 2011 proposal opened on November 23, 
2011, and ended on January 31, 2012. We received significant comments 
from industry representatives, environmental organizations local 
community groups. We also met with stakeholders (from industry, 
community groups and environmental organizations) after proposal to 
further discuss their comments, concerns and related issues. After 
reviewing the comments and after consideration of additional data and 
information received since the 2011 proposal, we determined it is

[[Page 60244]]

appropriate to revise some of our analyses and publish a supplemental 
proposal. Therefore, in today's Notice of Supplemental Proposed 
Rulemaking we present revised analyses, and based on those analyses we 
are proposing revised amendments for the items listed above to allow 
the public an opportunity to review and comment on these revised 
analyses and revised proposed amendments. In addition, we have 
reevaluated the proposed affirmative defense provisions in light of a 
recent court decision vacating an affirmative defense in one of the 
EPA's Section 112(d) regulations. NRDC v. EPA, 749 F.3d 1055 (D.C. 
Cir., 2014) (vacating affirmative defense provisions in Section 112(d) 
rule establishing emission standards for Portland cement kilns). In 
this supplemental proposal, we are withdrawing our 2011 proposal to 
include an affirmative defense provision in this regulation.
    However, we also proposed other requirements in the 2011 proposal 
(listed below) for which we have made no revisions to the analyses, we 
are not proposing any changes and are not reopening for public comment. 
The other requirements that we proposed in the 2011 proposal, for which 
we are not re-opening for comment, are the following:
     PM standards for metal oxygen refining processes and 
crushing and screening operations;
     emissions limits for formaldehyde;
     elimination of SSM exemptions; and
     electronic reporting.
We will address the comments we received on these other proposed 
requirements during the public comment period for the 2011 proposal at 
the time we take final action.
    In the 2011 proposal, we also included information about several 
ATSDR health consultations and a study (Kim et al.) that had been 
conducted in the Marietta area. We note that the Kim et al. study was 
included in the 2012 ATSDR review of manganese. Since the 2011 
proposal, additional studies on the potential toxicity of manganese 
have been published. These studies add to the literature regarding 
potential health effects from exposure to manganese and will be 
included, along with the complete body of scientific evidence, in 
future reviews of manganese toxicity.

D. What data collection activities were conducted to support this 
action?

    Commenters on the 2011 proposal expressed concern that the data set 
used in the risk assessment did not adequately reflect current 
operations at the plants. In response to these comments, we worked with 
the facilities to address these concerns and we obtained a significant 
amount of new data in order to establish a more robust dataset than the 
dataset we had for the 2011 proposal. Specifically, the plants provided 
data collected during their 2011 and 2012 compliance tests and, in 
response to an Information Collection Request (ICR) from the EPA in 
December 2012, they conducted more tests in the spring of 2013. This 
combined testing effort provided the following data:
     Additional stack test data for arsenic, cadmium, chromium, 
lead, manganese, mercury, nickel, HCl, formaldehyde, PAH, 
polychlorinated biphenyls (PCB) and dioxins/furans;
     Test data collected using updated, state-of-the-art test 
methods and procedures;
     Hazardous air pollutant (HAP) test data for all 
operational furnaces;
     Test data obtained during different seasonal conditions 
(i.e., spring and fall);
     Test data for both products (ferromanganese and 
silicomanganese) for both furnaces at Eramet (Felman only produces 
silicomanganese).
    With the new data, we no longer have to extrapolate HAP emissions 
from a ratio of PM to HAP emissions from just one or two tested 
furnaces. We are also using test data collected using state-of-the-art 
test methods that provide better QA/QC of the test results. For 
mercury, test data were collected for the supplemental proposal using 
EPA Method 30B, which requires paired samples collected for each test 
run, in addition to a spiked sample during the 3-run test. Test data 
for PAH were collected using CARB 429, which provides greater 
sensitivity, precision and identification of individual PAH compounds 
as compared to Method 0010 which was used for previous tests. We also 
received PCB and dioxin/furan test data that were collected using CARB 
428, which uses high resolution instruments and provides a specific 
procedure for measuring PCBs in addition to dioxin/furans.
    The data described above, which we received prior to summer 2014, 
were incorporated into our risk assessment, technology review and other 
MACT analyses presented in this Notice. However, we recently received 
additional test reports and data for PAH, mercury and PM emissions from 
one of the furnaces at Eramet (Furnace 12). We also received 
additional data on PM emissions for Furnaces 1 and 12 
at Eramet and for the tapping baghouse at Eramet. We have not yet 
completed our technical review of these new data and we were not able 
to incorporate these new data (on PAHs, PM, or Hg) into our RTR or MACT 
analyses in time for the publication of today's Notice.\5\ \6\ These 
test reports (which we received on August 19, 2014) are available in 
the docket for today's action. We have not yet determined the technical 
viability of these data or how these data would affect the RTR and MACT 
analyses. Nevertheless, we seek comment on these new data and how these 
data would impact our analyses and results presented in today's Notice. 
Based on comments and information that we receive in response to this 
supplemental proposal, and after we complete our review of these data, 
we will consider these data as appropriate as we develop the final 
rule.
---------------------------------------------------------------------------

    \5\ Emission Measurement Summary Report. Furnace No. 12 
Scrubber. PAHs and Mercury. Eramet Marietta, Inc. Marietta, OH. 
Prepared for: Eramet Marietta, Inc. Marietta, Ohio. Prepared by 
Environmental Quality Management, Inc. 1800 Carillon Boulevard, 
Cincinnati, Ohio 45240. January 2013.
    \6\ Emission Measurement Summary Report. Filterable Particulate 
Matter Furnaces 1 and 12. Eramet Marietta, Inc. Marietta, OH. 
Prepared for: Eramet Marietta, Inc. Marietta, Ohio 45750-0299 
Prepared by: Environmental Quality Management, Inc., Cincinnati, 
Ohio 45240. April 2014.
---------------------------------------------------------------------------

    Commenters also expressed concern that the estimated cost and 
operational impacts of the 2011 proposed process fugitive standards 
based on use of a total building enclosure requirement were 
significantly underestimated. In their comments both companies 
submitted substantial additional information and estimates regarding 
the elements, costs and impacts involved with constructing and 
operating a full building enclosure for their facilities. We also 
received comments saying that full-enclosure with negative pressure can 
lead to worker safety and health issues related to indoor air quality 
if the systems are not designed and operated appropriately to provide 
sufficient air exchanges and air conditioning in the work space. 
Furthermore, in their comments and in subsequent meetings and other 
communications, the companies also provided design and cost information 
for an alternative approach to substantially reduce fugitive emissions 
based on enhanced local capture and control of these emissions at each 
plant. In the summer of 2012 and fall of 2013, both plants submitted 
updated enhanced capture plans and cost estimates to implement those 
plans. We also consulted with outside ventilation experts and control 
equipment vendors to re-evaluate the costs of process fugitive capture 
as well as costs of other control measures such as activated carbon 
injection. We also gathered a

[[Page 60245]]

substantial amount of opacity data from both facilities and collected 
additional information regarding the processes, control technologies 
and modeling input parameters (such as stack release heights and 
fugitive emissions release characteristics). We reviewed and evaluated 
these data and information provided by the facilities, the ventilation 
experts and vendors, and revised our analyses accordingly.

III. Analytical Procedures

A. For purposes of this supplemental proposal, how did we estimate the 
post-MACT risks posed by the Ferroalloys Production Source Category?

    The EPA conducted a risk assessment that provides estimates of the 
MIR posed by the HAP emissions from each source in the source category, 
the hazard index (HI) for chronic exposures to HAP with the potential 
to cause noncancer health effects and the hazard quotient (HQ) for 
acute exposures to HAP with the potential to cause noncancer health 
effects. The assessment also provides estimates of the distribution of 
cancer risks within the exposed populations, cancer incidence and an 
evaluation of the potential for adverse environmental effects. The risk 
assessment consisted of eight primary steps, as discussed in detail in 
the 2011 proposal. The docket for this rulemaking contains the 
following document which provides more information on the risk 
assessment inputs and models: Residual Risk Assessment for the 
Ferroalloys Production Source Category in Support of the September 2014 
Supplemental Proposal (risk assessment document). The methods used to 
assess risks (as described in the eight primary steps below) are 
consistent with those peer-reviewed by a panel of the EPA's Science 
Advisory Board (SAB) in 2009 and described in their peer review report 
issued in 2010; \7\ they are also consistent with the key 
recommendations contained in that report.
---------------------------------------------------------------------------

    \7\ U.S. EPA SAB. Risk and Technology Review (RTR) Risk 
Assessment Methodologies: For Review by the EPA's Science Advisory 
Board with Case Studies--MACT I Petroleum Refining Sources and 
Portland Cement Manufacturing, May 2010.
---------------------------------------------------------------------------

1. How did we estimate actual emissions and identify the emissions 
release characteristics?
    As explained previously, the revised data set for the ferroalloys 
production source category, derived from the two existing 
ferromanganese and silicomanganese production facilities, constitutes 
the basis for the revised risk assessment. We estimated the magnitude 
of emissions using emissions test data collected through ICRs along 
with additional data submitted voluntarily by the companies. We also 
collected information regarding emissions release characteristics such 
as stack heights, stack gas exit velocities, stack temperatures and 
source locations. In addition to the quality assurance (QA) of the 
source data for the facilities contained in the data set, we also 
checked the coordinates of every emission source in the data set 
through visual observations using tools such as GoogleEarth and 
ArcView. Where coordinates were found to be incorrect, we identified 
and corrected them to the extent possible. We also performed a QA 
assessment of the emissions data and release characteristics to ensure 
the data were reliable and that there were no outliers. The emissions 
data and the methods used to estimate emissions from all the various 
emissions sources are described in more detail in the technical 
document: Revised Development of the RTR Emissions Dataset for the 
Ferroalloys Production Source Category for the 2014 Supplemental 
Proposal, which is available in the docket for this action.
2. How did we estimate MACT-allowable emissions?
    The available emissions data in the RTR emissions dataset include 
estimates of the mass of HAP emitted during the specified annual time 
period. In some cases, these ``actual'' emission levels are lower than 
the emission levels required to comply with the MACT standards. The 
emissions level allowed to be emitted by the MACT standards is referred 
to as the ``MACT-allowable'' emissions level. We discussed the use of 
both MACT-allowable and actual emissions in the final Coke Oven 
Batteries residual risk rule (70 FR 19998-19999, April 15, 2005) and in 
the proposed and final Hazardous Organic NESHAP residual risk rules (71 
FR 34428, June 14, 2006, and 71 FR 76609, December 21, 2006, 
respectively). In those previous actions, we noted that assessing the 
risks at the MACT-allowable level is inherently reasonable since these 
risks reflect the maximum level facilities could emit and still comply 
with national emission standards. We also explained that it is 
reasonable to consider actual emissions, where such data are available, 
in both steps of the risk analysis, in accordance with the Benzene 
NESHAP approach. (54 FR 38044, September 14, 1989.)
    For this supplemental proposal, we evaluated allowable stack 
emissions based on the level of control required by the 1999 MACT 
standards. We also evaluated the level of reported actual emissions and 
available information on the level of control achieved by the emissions 
controls in use. Further explanation is provided in the technical 
document: Revised Development of the RTR Emissions Dataset for the 
Ferroalloys Production Source Category for the 2014 Supplemental 
Proposal, which is available in the docket.
3. How did we conduct dispersion modeling, determine inhalation 
exposures and estimate individual and population inhalation risks?
    Both long-term and short-term inhalation exposure concentrations 
and health risks from the source category addressed in this proposal 
were estimated using the Human Exposure Model (Community and Sector 
HEM-3 version 1.1.0). 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 (km) of the modeled sources \8\, and (3) estimating 
individual and population-level inhalation risks using the exposure 
estimates and quantitative dose-response information.
---------------------------------------------------------------------------

    \8\ This metric comes from the Benzene NESHAP. See 54 FR 38046.
---------------------------------------------------------------------------

    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.\9\ 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 1 year (2011) of 
hourly surface and upper air observations for more than 800 
meteorological stations, selected to provide coverage of the United 
States and Puerto Rico. A second library of United States Census Bureau 
census block \10\ internal point locations and populations provides the 
basis of human exposure calculations (U.S. Census, 2010). 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

[[Page 60246]]

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. These values are available at: 
http://www.epa.gov/ttn/atw/toxsource/summary.html and are discussed in 
more detail later in this section.
---------------------------------------------------------------------------

    \9\ U.S. EPA. Revision to the Guideline on Air Quality Models: 
Adoption of a Preferred General Purpose (Flat and Complex Terrain) 
Dispersion Model and Other Revisions (70 FR 68218, November 9, 
2005).
    \10\ A census block is the smallest geographic area for which 
census statistics are tabulated.
---------------------------------------------------------------------------

    In developing the risk assessment for chronic exposures, we used 
the estimated annual average ambient air concentrations of each HAP 
emitted by each source for which we have emissions data 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. We 
calculated the MIR for each facility as the cancer risk associated with 
a continuous lifetime (24 hours per day, 7 days per week, and 52 weeks 
per year for a 70-year period) exposure to the maximum concentration at 
the centroid of inhabited census blocks. Individual cancer risks were 
calculated by multiplying the estimated lifetime exposure to the 
ambient concentration of each of the HAP (in micrograms per cubic meter 
([mu]g/m\3\)) by its unit risk estimate (URE). The URE is an upper 
bound estimate of an individual's probability of contracting cancer 
over a lifetime of exposure to a concentration of 1 microgram of the 
pollutant per cubic meter of air. For residual risk assessments, we 
generally use URE values from the EPA's Integrated Risk Information 
System (IRIS). For carcinogenic pollutants without EPA IRIS values, we 
look to other reputable sources of cancer dose-response values, often 
using California EPA (CalEPA) URE values, where available. In cases 
where new, scientifically credible dose response values have been 
developed in a manner consistent with the EPA guidelines and have 
undergone a peer review process similar to that used by the EPA, we may 
use such dose-response values in place of, or in addition to, other 
values, if appropriate.
    In the case of nickel compounds, to provide a conservative estimate 
of potential cancer risks, we used the IRIS URE value for nickel 
subsulfide (which is considered the most potent carcinogen among all 
nickel compounds) in the assessment for the 2011 proposed rule for 
ferroalloys production. In the 2011 proposed rule, the determination of 
the percent of nickel subsulfide was considered a major factor for 
estimating the risks of cancer due to nickel-containing emissions. 
Nickel speciation information for some of the largest nickel-emitting 
sources (including oil combustion, coal combustion and others) 
suggested that at least 35 percent of total nickel emissions may be 
soluble compounds and that the cancer risk for the mixture of inhaled 
nickel compounds (based on nickel subsulfide and representative of pure 
insoluble crystalline nickel) was derived to reflect the assumption 
that 65 percent of the total mass of nickel may be carcinogenic.
    Based on consistent views of major scientific bodies (i.e., 
National Toxicology Program (NTP) in their 12th Report of the 
Carcinogens (ROC) \11\, International Agency for Research on Cancer 
(IARC) \12\ and other international agencies) \13\ that consider all 
nickel compounds to be carcinogenic, we currently consider all nickel 
compounds to have the potential of being carcinogenic to humans. The 
12th Report of the Carcinogens states that the ``combined results of 
epidemiological studies, mechanistic studies, and carcinogenic studies 
in rodents support the concept that nickel compounds generate nickel 
ions in target cells at sites critical for carcinogenesis, thus 
allowing consideration and evaluation of these compounds as a single 
group.'' Although the precise nickel compound (or compounds) 
responsible for carcinogenic effects in humans is not always clear, 
studies indicate that nickel sulfate and the combinations of nickel 
sulfides and oxides encountered in the nickel refining industries cause 
cancer in humans (these studies are summarized in a review by Grimsrud 
et al., 2010 \14\). The major scientific bodies mentioned above have 
also recognized that there are differences in toxicity and/or 
carcinogenic potential across the different nickel compounds.
---------------------------------------------------------------------------

    \11\ National Toxicology Program (NTP), 2011. Report on 
carcinogens. 12th ed. Research Triangle Park, NC: US Department of 
Health and Human Services (DHHS), Public Health Service. Available 
online at http://ntp.niehs.nih.gov/ntp/roc/twelfth/roc12.pdf.
    \12\ International Agency for Research on Cancer (IARC), 1990. 
IARC monographs on the evaluation of carcinogenic risks to humans. 
Chromium, nickel, and welding. Vol. 49. Lyons, France: International 
Agency for Research on Cancer, World Health Organization Vol. 
49:256.
    \13\ World Health Organization (WHO, 1991) and the European 
Union's Scientific Committee on Health and Environmental Risks 
(SCHER, 2006).
    \14\ Grimsrud TK and Andersen A. Evidence of carcinogenicity in 
humans of water-soluble nickel salts. J Occup Med Toxicol 2010, 5:1-
7. Available online at http://www.ossup-med.com/content/5/1/7.
---------------------------------------------------------------------------

    In the inhalation risk assessment for the 2011 proposed rule, to 
take a conservative approach, we considered all nickel compounds to 
have the same carcinogenic potential as nickel subsulfide and used the 
IRIS URE for nickel subsulfide to estimate risks due to all nickel 
emissions from the source category. However, given that there are two 
additional URE values \15\ derived for exposure to mixtures of nickel 
compounds, as a group, that are 2-3 fold lower than the IRIS URE for 
nickel subsulfide, the EPA also considers it reasonable to use a value 
that is 50 percent of the IRIS URE for nickel subsulfide for providing 
an estimate of the lower end of the plausible range of cancer potency 
values for different mixtures of nickel compounds. In the public 
comments provided in response to the proposal and available in the 
docket, one facility provided additional data in the form of a 
laboratory test report that indicated it would be unlikely that 100 
percent of the nickel from the furnace would be in the form of nickel 
subsulfide. Given our current knowledge of the carcinogenic potential 
of all nickel compounds, and the potential differences in carcinogenic 
potential across nickel compounds, we consider it reasonable to use a 
value that is 50 percent of the IRIS URE for nickel subsulfide for 
providing an estimate of the cancer potency values for different 
mixtures of nickel compounds in the revised data set for the current 
supplemental proposal.
---------------------------------------------------------------------------

    \15\ Two UREs (other than the current IRIS values) have been 
derived for nickel compounds as a group: One developed by the 
California Department of Health Services (http://www.arb.ca.gov/toxics/id/summary/nickel_tech_b.pdf) and the other by the Texas 
Commission on Environmental Quality (http://www.epa.gov/ttn/atw/nata1999/99pdfs/healtheffectsinfo.pdf).
---------------------------------------------------------------------------

    The EPA estimated incremental individual lifetime cancer risks 
associated with emissions from the facilities in the source category as 
the sum of the risks for each of the carcinogenic HAP (including those 
classified as carcinogenic to humans, likely to be carcinogenic to 
humans, and suggestive evidence of carcinogenic potential \16\) emitted 
by the modeled sources. Cancer incidence and the distribution of 
individual cancer risks for the population within 50 km of the sources 
were also estimated for the source category as part of this

[[Page 60247]]

assessment by summing individual risks. A distance of 50 km is 
consistent with both the analysis supporting the 1989 Benzene NESHAP 
(54 FR 38044, September 14, 1989) and the limitations of Gaussian 
dispersion models, including AERMOD.
---------------------------------------------------------------------------

    \16\ These classifications also coincide with the terms ``known 
carcinogen, probable carcinogen, and possible carcinogen,'' 
respectively, which are the terms advocated in the EPA's previous 
Guidelines for Carcinogen Risk Assessment, published in 1986 (51 FR 
33992, September 24, 1986). Summing the risks of these individual 
compounds to obtain the cumulative cancer risks is an approach that 
was recommended by the EPA's Science Advisory Board (SAB) in their 
2002 peer review of EPA's National Air Toxics Assessment (NATA) 
entitled, NATA--Evaluating the National-scale Air Toxics Assessment 
1996 Data--an SAB Advisory, available at: http://yosemite.epa.gov/
sab/sabproduct.nsf/214C6E915BB04E14852570CA007A682C/$File/
ecadv02001.pdf.
---------------------------------------------------------------------------

    To assess the risk of non-cancer health effects from chronic 
exposures, we summed the HQ for each of the HAP that affects a common 
target organ system to obtain the HI for that target organ system (or 
target organ-specific HI, TOSHI). The HQ is the estimated exposure 
divided by the chronic reference value, which is a value selected from 
one of several sources. First, the chronic reference level can be the 
EPA reference concentration (RfC) (http://www.epa.gov/riskassessment/glossary.htm), 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.'' Alternatively, in cases where an RfC from the EPA's IRIS 
database is not available or where the EPA determines that using a 
value other than the RfC is appropriate, the chronic reference level 
can be a value from the following prioritized sources: (1) The Agency 
for Toxic Substances and Disease Registry Minimum Risk Level (MRL) 
(http://www.atsdr.cdc.gov/mrls/index.asp), which is defined as ``an 
estimate of daily human exposure to a hazardous substance that is 
likely to be without an appreciable risk of adverse non-cancer health 
effects (other than cancer) over a specified duration of exposure''; 
(2) the CalEPA Chronic Reference Exposure Level (REL) (http://www.oehha.ca.gov/air/hot_spots/pdf/HRAguidefinal.pdf), which is defined 
as ``the concentration level (that is expressed in units of micrograms 
per cubic meter ([mu]g/m\3\) for inhalation exposure and in a dose 
expressed in units of milligram per kilogram-day (mg/kg-day) for oral 
exposures), at or below which no adverse health effects are anticipated 
for a specified exposure duration''; or (3), as noted above, a 
scientifically credible dose-response value that has been developed in 
a manner consistent with the EPA guidelines and has undergone a peer 
review process similar to that used by the EPA, in place of or in 
concert with other values.
    For the ferroalloys source category, we applied this policy in our 
estimate of noncancer inhalation hazards and note the following related 
to manganese. There is an existing IRIS RfC for manganese (Mn) 
published in 1993.\17\ This value was used in the RTR risk assessment 
supporting the Ferroalloys Notice of Proposed Rulemaking.\18\ However, 
since the 2011 proposal, ATSDR has published an assessment of Mn 
toxicity (2012) which includes a chronic inhalation value (i.e., an 
ATSDR Minimal Risk Level or MRL).\19\ Both the 1993 IRIS RfC and the 
2012 ATSDR MRL were based on the same study (Roels et al., 1993). In 
developing their assessment, ATSDR used updated dose-response modeling 
methodology (benchmark dose approach) and considered recent 
pharmacokinetic findings to support their MRL derivation. Consistent 
with Agency policy, which was supported by SAB,\20\ the EPA has chosen 
in this instance to rely on the ATSDR MRL for Mn in the current 
ferroalloys supplemental proposal.
---------------------------------------------------------------------------

    \17\ US EPA Integrated Risk Information System Review of 
Manganese (1993) available at http://www.epa.gov/iris/subst/0373.htm.
    \18\ 2011 Notice of proposed Rulemaking reference (76 FR 72508).
    \19\ Agency for Toxic Substances & Disease Registry 
Toxicological Profile for Manganese (2012) available at http://www.atsdr.cdc.gov/toxprofiles/tp.asp?id=102&tid=23.
    \20\ The SAB peer review of RTR Risk Assessment Methodologies is 
available at: http://yosemite.epa.gov/sab/sabproduct.nsf/
4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-unsigned.pdf.
---------------------------------------------------------------------------

    The EPA also evaluated screening estimates of acute exposures and 
risks for each of the HAP at the point of highest potential off-site 
exposure for each facility. To do this, the EPA estimated the risks 
when both the peak hourly emissions rate and worst-case dispersion 
conditions occur. We also assume that a person is located at the point 
of highest impact during that same time. In accordance with our mandate 
in section 112 of the Clean Air Act, we use the point of highest off-
site exposure to assess the potential risk to the maximally exposed 
individual. The acute HQ is the estimated acute exposure divided by the 
acute dose-response value. In each case, the EPA calculated acute HQ 
values using best available, short-term dose-response values. These 
acute dose-response values, which are described below, include the 
acute REL, acute exposure guideline levels (AEGL) and emergency 
response planning guidelines (ERPG) for 1-hour exposure durations. As 
discussed below, we used conservative assumptions for emissions rates, 
meteorology and exposure location for our acute analysis.
    As described in the CalEPA's Air Toxics Hot Spots Program Risk 
Assessment Guidelines, Part I, The Determination of Acute Reference 
Exposure Levels for Airborne Toxicants, an acute REL value (http://www.oehha.ca.gov/air/pdf/acuterel.pdf) is defined as ``the 
concentration level at or below which no adverse health effects are 
anticipated for a specified exposure duration.'' Id. at page 2. Acute 
REL values are based on the most sensitive, relevant, adverse health 
effect reported in the peer-reviewed medical and toxicological 
literature. Acute REL values are designed to protect the most sensitive 
individuals in the population through the inclusion of margins of 
safety. Because margins of safety are incorporated to address data gaps 
and uncertainties, exceeding the REL does not automatically indicate an 
adverse health impact.
    As we state above, in assessing the potential risks associated with 
acute exposures to HAP, we do not follow a prioritization scheme and 
therefore we consider available dose-response values from multiple 
authoritative sources. In the RTR program, EPA assesses acute risk 
using toxicity values derived from one hour exposures. Based on an in-
depth examination of the available acute value for nickel [California 
EPA's acute (1-hour) REL], we have concluded that this value is not 
appropriate to use to support EPA's risk and technology review rules. 
This conclusion takes into account: The effect on which the acute REL 
is based; aspects of the methodology used in its derivation; and how 
this assessment stands in comparison to the ATSDR toxicological 
assessment, which considered the broader nickel health effects 
database.
    The broad nickel noncancer health effects database strongly 
suggests that the respiratory tract is the primary target of nickel 
toxicity following inhalation exposure. The available database on acute 
noncancer respiratory effects is limited and was considered unsuitable 
for quantitative analysis of nickel toxicity by both California EPA 
\21\ and ATSDR.\22\ The California EPA's acute (1-hour) REL is based on 
an alternative endpoint, immunotoxicity in mice, specifically depressed 
antibody response measured in an antibody plaque assay.
---------------------------------------------------------------------------

    \21\ http://oehha.ca.gov/air/allrels.html.
    \22\ http://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=44.
---------------------------------------------------------------------------

    In addition, the current California acute (1-hour) REL for Ni 
includes the application of methods that are different from those 
described in EPA guidelines. Specifically, the (1-hour) REL applies 
uncertainty factors that depart from the defaults in EPA guidelines and 
does not

[[Page 60248]]

apply an inhalation dosimetric adjustment factor.
    Further, the ATSDR's intermediate MRL (relevant to Ni exposures for 
a time frame between 14 and 364 days), was established at the same 
concentration as the California EPA (1- hour) REL, indicating that 
exposure to this concentration ``is likely to be without appreciable 
risk of adverse noncancer effects'' (MRL definition) \23\ for up to 364 
days.
---------------------------------------------------------------------------

    \23\ Agency for Toxic Substances and Disease Registry (ATSDR), 
Toxic Substances Portal. Minimal Risk Levels (MRLs) http://www.atsdr.cdc.gov/mrls/index.asp.
---------------------------------------------------------------------------

    We have high confidence in the nickel ATSDR intermediate MRL. Our 
analysis of the broad toxicity database for nickel indicates that this 
value is based on the most biologically-relevant endpoint. That is, the 
intermediate MRL is based on a scientifically sound study of acute 
respiratory toxicity. Furthermore, this value is supported by a robust 
subchronic nickel toxicity database and was derived following 
guidelines that are consistent with EPA guidelines.\24\ Finally, there 
are no AEGL-1/ERPG-1 or AEGL-2/ERPG-2 values available for nickel. 
Thus, for all the above mentioned reasons, we will not include Ni in 
our acute analysis for this source category or in future assessments 
unless and until an appropriate value becomes available.
---------------------------------------------------------------------------

    \24\ US EPA 2002. Review of the reference dose and reference 
concentration processes (EPA/630/P-02/002F), December 2002, http://www.epa.gov/raf/publications/pdfs/rfd-final.pdf
---------------------------------------------------------------------------

    AEGL values were derived in response to recommendations from the 
National Research Council (NRC). As described in Standing Operating 
Procedures (SOP) of the National Advisory Committee on Acute Exposure 
Guideline Levels for Hazardous Substances (http://www.epa.gov/oppt/aegl/pubs/sop.pdf),\25\ ``the NRC's previous name for acute exposure 
levels--community emergency exposure levels--was replaced by the term 
AEGL to reflect the broad application of these values to planning, 
response and prevention in the community, the workplace, 
transportation, the military and the remediation of Superfund sites.'' 
Id. at 2. This document also states that AEGL values ``represent 
threshold exposure limits for the general public and are applicable to 
emergency exposures ranging from 10 minutes to eight hours.'' Id. at 2.
---------------------------------------------------------------------------

    \25\ National Academy of Sciences (NAS), 2001. Standing 
Operating Procedures for Developing Acute Exposure Levels for 
Hazardous Chemicals, page 2.
---------------------------------------------------------------------------

    The document lays out the purpose and objectives of AEGL by stating 
that ``the primary purpose of the AEGL program and the National 
Advisory Committee for Acute Exposure Guideline Levels for Hazardous 
Substances is to develop guideline levels for once-in-a-lifetime, 
short-term exposures to airborne concentrations of acutely toxic, high-
priority chemicals.'' Id. at 21. In detailing the intended application 
of AEGL values, the document states that ``[i]t is anticipated that the 
AEGL values will be used for regulatory and nonregulatory purposes by 
U.S. Federal and state agencies and possibly the international 
community in conjunction with chemical emergency response, planning, 
and prevention programs. More specifically, the AEGL values will be 
used for conducting various risk assessments to aid in the development 
of emergency preparedness and prevention plans, as well as real-time 
emergency response actions, for accidental chemical releases at fixed 
facilities and from transport carriers.'' Id. at 31.
    The AEGL-1 value is then specifically defined as ``the airborne 
concentration (expressed as ppm (parts per million) or mg/m\3\ 
(milligrams per cubic meter)) of a substance above which it is 
predicted that the general population, including susceptible 
individuals, could experience notable discomfort, irritation, or 
certain asymptomatic nonsensory effects. However, the effects are not 
disabling and are transient and reversible upon cessation of 
exposure.'' Id. at 3. The document also notes that, ``Airborne 
concentrations below AEGL-1 represent exposure levels that can produce 
mild and progressively increasing but transient and nondisabling odor, 
taste, and sensory irritation or certain asymptomatic, nonsensory 
effects.'' Id. Similarly, the document defines AEGL-2 values as ``the 
airborne concentration (expressed as parts per million or milligrams 
per cubic meter) of a substance above which it is predicted that the 
general population, including susceptible individuals, could experience 
irreversible or other serious, long-lasting adverse health effects or 
an impaired ability to escape.'' Id.
    ERPG values are derived for use in emergency response, as described 
in the American Industrial Hygiene Association's ERP Committee document 
entitled, ERPGS Procedures and Responsibilities (http://sp4m.aiha.org/insideaiha/GuidelineDevelopment/ERPG/Documents/ERP-SOPs2006.pdf), which 
states that, ``Emergency Response Planning Guidelines were developed 
for emergency planning and are intended as health based guideline 
concentrations for single exposures to chemicals.'' \26\ Id. at 1. The 
ERPG-1 value is defined as ``the maximum airborne concentration below 
which it is believed that nearly all individuals could be exposed for 
up to 1 hour without experiencing other than mild transient adverse 
health effects or without perceiving a clearly defined, objectionable 
odor.'' Id. at 2. Similarly, the ERPG-2 value is defined as ``the 
maximum airborne concentration below which it is believed that nearly 
all individuals could be exposed for up to one hour without 
experiencing or developing irreversible or other serious health effects 
or symptoms which could impair an individual's ability to take 
protective action.'' Id. at 1.
---------------------------------------------------------------------------

    \26\ ERP Committee Procedures and Responsibilities. November 1, 
2006. American Industrial Hygiene Association.
---------------------------------------------------------------------------

    As can be seen from the definitions above, the AEGL and ERPG values 
include the similarly-defined severity levels 1 and 2. For many 
chemicals, a severity level 1 value AEGL or ERPG has not been developed 
because the types of effects for these chemicals are not consistent 
with the AEGL-1/ERPG-1 definitions; in these instances, we compare 
higher severity level AEGL-2 or ERPG-2 values to our modeled exposure 
levels to screen for potential acute concerns. When AEGL-1/ERPG-1 
values are available, they are used in our acute risk assessments.
    Acute REL values for 1-hour exposure durations are typically lower 
than their corresponding AEGL-1 and ERPG-1 values. Even though their 
definitions are slightly different, AEGL-1 values are often the same as 
the corresponding ERPG-1 values, and AEGL-2 values are often equal to 
ERPG-2 values. Maximum HQ values from our acute screening risk 
assessments typically result when basing them on the acute REL value 
for a particular pollutant. In cases where our maximum acute HQ value 
exceeds 1, we also report the HQ value based on the next highest acute 
dose-response value (usually the AEGL-1 and/or the ERPG-1 value).
    To develop screening estimates of acute exposures in the absence of 
hourly emissions data, generally we first develop estimates of maximum 
hourly emissions rates by multiplying the average actual annual hourly 
emissions rates by a default factor to cover routinely variable 
emissions. We choose the factor to use partially based on process 
knowledge and engineering judgment. The factor chosen also reflects a 
Texas study of short-term emissions variability, which showed that most 
peak emission events in a

[[Page 60249]]

heavily-industrialized four-county area (Harris, Galveston, Chambers 
and Brazoria Counties, Texas) were less than twice the annual average 
hourly emissions rate. The highest peak emissions event was 74 times 
the annual average hourly emissions rate, and the 99th percentile ratio 
of peak hourly emissions rate to the annual average hourly emissions 
rate was 9.\27\ Considering this analysis, to account for more than 99 
percent of the peak hourly emissions, we apply a conservative screening 
multiplication factor of 10 to the average annual hourly emissions rate 
in our acute exposure screening assessments as our default approach. 
However, we use a factor other than 10 if we have information that 
indicates that a different factor is appropriate for a particular 
source category.
---------------------------------------------------------------------------

    \27\ See http://www.tceq.state.tx.us/compliance/field_ops/eer/index.html or docket to access the source of these data.
---------------------------------------------------------------------------

    For this source category, data were available to determine process-
specific factors. Some processes, for example the electric arc 
furnaces, operate continuously so there are no peak emissions. These 
processes received a factor of 1 in the acute assessment. Other 
processes, for example tapping and casting, have specific cycles, with 
peak emissions occurring for a part of that cycle (e.g., 30 minutes 
during a 2-hour period). For these processes, we used a factor of 4 in 
the acute assessment. Even with data available to develop process-
specific factors, our acute assessment is still conservative in that it 
assumes that every process releases its peak emissions at the same hour 
and that this is the same hour as the worst-case dispersion conditions. 
This results in a highly conservative exposure scenario. A further 
discussion of why this factor of 4 was chosen can be found in the 
memorandum, Revised Development of the RTR Emissions Dataset for the 
Ferroalloys Production Source Category for the 2014 Supplemental 
Proposal, available in the docket for this rulemaking.
    As part of our acute risk assessment process, for cases where acute 
HQ values from the screening step were less than or equal to 1 (even 
under the conservative assumptions of the screening analysis), acute 
impacts were deemed negligible and no further analysis was performed. 
In cases where an acute HQ from the screening step was greater than 1, 
additional site-specific data were considered to develop a more refined 
estimate of the potential for acute impacts of concern. For this source 
category, the data refinements employed consisted of determining that 
the receptor with the maximum concentration was off of plant property. 
These refinements are discussed more fully in the Residual Risk 
Assessment for the Ferroalloys Production Source Category in Support of 
the September 2014 Supplemental Proposal, which is available in the 
docket for this source category. Ideally, we would prefer to have 
continuous measurements over time to see how the emissions vary by each 
hour over an entire year. Having a frequency distribution of hourly 
emissions rates over a year would allow us to perform a probabilistic 
analysis to estimate potential threshold exceedances and their 
frequency of occurrence. Such an evaluation could include a more 
complete statistical treatment of the key parameters and elements 
adopted in this screening analysis. Recognizing that this level of data 
is rarely available, we instead rely on the multiplier approach.
    To better characterize the potential health risks associated with 
estimated acute exposures to HAP, and in response to a key 
recommendation from the SAB's peer review of the EPA's RTR risk 
assessment methodologies,\28\ we generally examine a wider range of 
available acute health metrics (e.g., RELs, AEGLs) than we do for our 
chronic risk assessments. This is in response to the SAB's 
acknowledgement that there are generally more data gaps and 
inconsistencies in acute reference values than there are in chronic 
reference values. In some cases, when Reference Value Arrays \29\ for 
HAP have been developed, we consider additional acute values (i.e., 
occupational and international values) to provide a more complete risk 
characterization.
---------------------------------------------------------------------------

    \28\ The SAB peer review of RTR Risk Assessment Methodologies is 
available at: http://yosemite.epa.gov/sab/sabproduct.nsf/
4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-unsigned.pdf.
    \29\ U.S. EPA. (2009) Chapter 2.9 Chemical Specific Reference 
Values for Formaldehyde in Graphical Arrays of Chemical-Specific 
Health Effect Reference Values for Inhalation Exposures (Final 
Report). U.S. Environmental Protection Agency, Washington, DC, EPA/
600/R-09/061 and available online at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=211003.
---------------------------------------------------------------------------

4. How did we conduct the multipathway exposure and risk screening?
    The EPA conducted a screening analysis examining the potential for 
significant human health risks due to exposures via routes other than 
inhalation (i.e., ingestion). We first determined whether any sources 
in the source category emitted any hazardous air pollutants known to be 
persistent and bioaccumulative in the environment (PB-HAP). The PB-HAP 
compounds or compound classes are identified for the screening from the 
EPA's Air Toxics Risk Assessment Library (available at http://www2.epa.gov/fera/risk-assessment-and-modeling-air-toxics-risk-assessment-reference-library).
    For the Ferroalloys Production source category, we identified 
emissions of cadmium compounds, chlorinated dibenzodioxins and furans, 
lead compounds, mercury compounds and polycyclic organic matter. 
Because one or more of these PB-HAP are emitted by at least one 
facility in the Ferroalloys Production source category, we proceeded to 
the second step of the evaluation. In this step, we determined whether 
the facility-specific emissions rates of each of the emitted PB-HAP 
were large enough to create the potential for significant non-
inhalation human health risks under reasonable worst-case conditions. 
To facilitate this step, we developed emissions rate screening levels 
for several PB-HAP using a hypothetical upper-end screening exposure 
scenario developed for use in conjunction with the EPA's Total Risk 
Integrated Methodology.Fate, Transport, and Ecological Exposure 
(TRIM.FaTE) model. The PB-HAP with emissions rate screening level 
values are: Lead, cadmium, chlorinated dibenzodioxins and furans, 
mercury compounds, and polycyclic organic matter (POM). We conducted a 
sensitivity analysis on the screening scenario to ensure that its key 
design parameters would represent the upper end of the range of 
possible values, such that it would represent a conservative but not 
impossible scenario. The facility-specific emissions rates of these PB-
HAP were compared to the emission rate screening levels for these PB-
HAP to assess the potential for significant human health risks via non-
inhalation pathways. We call this application of the TRIM.FaTE model 
the Tier I TRIM-screen or Tier I screen.
    For the purpose of developing emissions rates for our Tier I TRIM-
screen, we derived emission levels for these PB-HAP (other than lead 
compounds) at which the maximum excess lifetime cancer risk would be 1-
in-1 million (i.e., for polychlorinated dibenzodioxins and furans and 
POM) or, for HAP that cause non-cancer health effects (i.e., cadmium 
compounds and mercury compounds), the maximum hazard quotient would be 
1. If the emissions rate of any PB-HAP included in the Tier I screen 
exceeds the Tier I screening emissions rate for any facility, we 
conduct a second screen, which we call the Tier II TRIM-screen or Tier 
II screen.

[[Page 60250]]

    In the Tier II screen, the location of each facility that exceeded 
the Tier I emission rate is used to refine the assumptions associated 
with the environmental scenario while maintaining the exposure scenario 
assumptions. We then adjust the risk-based Tier I screening level for 
each PB-HAP for each facility based on an understanding of how exposure 
concentrations estimated for the screening scenario change with 
meteorology and environmental assumptions. PB-HAP emissions that do not 
exceed these new Tier II screening levels are considered to pose no 
unacceptable risks. When facilities exceed the Tier II screening 
levels, it does not mean that multipathway impacts are significant, 
only that we cannot rule out that possibility based on the results of 
the screen.
    If the PB-HAP emissions for a facility exceed the Tier II screening 
emissions rate and data are available, we may decide to conduct a more 
refined multipathway assessment. A refined assessment replaces some of 
the assumptions made in the Tier II screen, with site-specific data. 
The refined assessment also uses the TRIM.FaTE model and facility-
specific emission rate screening levels that are created for each PB-
HAP. For the ferroalloys production source category, we did conduct a 
refined multipathway assessment for one facility in the category. A 
detailed discussion of the approach for this assessment can be found in 
Appendix 10 (Technical Support Document: Human Health Multipathway 
Residual Risk Assessment for the Ferroalloys Production Source 
Category) of the risk assessment document.
    In evaluating the potential multi-pathway risk from emissions of 
lead compounds, rather than developing a screening emissions rate for 
them, we compared maximum estimated chronic inhalation exposures with 
the level of the current National Ambient Air Quality Standard (NAAQS) 
for lead.\30\ Values below the level of the primary (health-based) lead 
NAAQS were considered to have a low potential for multi-pathway risk.
---------------------------------------------------------------------------

    \30\ In doing so, EPA notes that the legal standard for a 
primary NAAQS--that a standard is requisite to protect public health 
and provide an adequate margin of safety (CAA section 109(b))--
differs from the section 112(f) standard (requiring among other 
things that the standard provide an ``ample margin of safety''). 
However, the lead NAAQS is a reasonable measure of determining risk 
acceptability (i.e. the first step of the Benzene NESHAP analysis) 
since it is designed to protect the most susceptible group in the 
human population--children, including children living near major 
lead emitting sources. 73 FR 67002/3; 73 FR 67000/3; 73 FR 67005/1. 
In addition, applying the level of the primary lead NAAQS at the 
risk acceptability step is conservative, since that primary lead 
NAAQS reflects an adequate margin of safety.
---------------------------------------------------------------------------

    For further information on the multipathway analysis approach, see 
the Residual Risk Assessment for the Ferroalloys Production Source 
Category in Support of the September 2014 Supplemental Proposal, which 
is available in the docket for this action.
5. How did we assess risks considering the revised emissions control 
options?
    In addition to assessing baseline inhalation risks and potential 
multipathway risks, we also estimated risks considering the emissions 
reductions that would be achieved by the control options under 
consideration in this supplemental proposal. In these cases, the 
expected emissions reductions were applied to the specific HAP and 
emissions points in the RTR emissions dataset to develop corresponding 
estimates of risk that would exist after implementation of the proposed 
amendments in today's action.
6. How did we conduct the environmental risk screening assessment?
a. Adverse Environmental Effect
    The EPA has developed a screening approach to examine the potential 
for adverse environmental effects as required under section 
112(f)(2)(A) of the CAA. Section 112(a)(7) of the CAA defines ``adverse 
environmental effect'' as ``any significant and widespread adverse 
effect, which may reasonably be anticipated, to wildlife, aquatic life, 
or other natural resources, including adverse impacts on populations of 
endangered or threatened species or significant degradation of 
environmental quality over broad areas.''
b. Environmental HAP
    The EPA focuses on seven HAP, which we refer to as ``environmental 
HAP,'' in its screening analysis: Five persistent bioaccumulative HAP 
(PB-HAP) and two acid gases. The five PB-HAP are cadmium, dioxins/
furans, polycyclic organic matter (POM), mercury (both inorganic 
mercury and methyl mercury) and lead compounds. The two acid gases are 
hydrogen chloride (HCl) and hydrogen fluoride (HF). The rationale for 
including these seven HAP in the environmental risk screening analysis 
is presented below.
    The HAP that persist and bioaccumulate are of particular 
environmental concern because they accumulate in the soil, sediment and 
water. The PB-HAP are taken up, through sediment, soil, water, and/or 
ingestion of other organisms, by plants or animals (e.g., small fish) 
at the bottom of the food chain. As larger and larger predators consume 
these organisms, concentrations of the PB-HAP in the animal tissues 
increase as does the potential for adverse effects. The five PB-HAP we 
evaluate as part of our screening analysis account for 99.8 percent of 
all PB-HAP emissions nationally from stationary sources (on a mass 
basis from the 2005 NEI).
    In addition to accounting for almost all of the mass of PB-HAP 
emitted, we note that the TRIM.FaTE model that we use to evaluate 
multipathway risk allows us to estimate concentrations of cadmium 
compounds, dioxins/furans, POM and mercury in soil, sediment and water. 
For lead compounds, we currently do not have the ability to calculate 
these concentrations using the TRIM.FaTE model. Therefore, to evaluate 
the potential for adverse environmental effects from lead compounds, we 
compare the estimated HEM-modeled exposures from the source category 
emissions of lead with the level of the secondary National Ambient Air 
Quality Standard (NAAQS) for lead.\31\ We consider values below the 
level of the secondary lead NAAQS as unlikely to cause adverse 
environmental effects.
---------------------------------------------------------------------------

    \31\ The secondary lead NAAQS is a reasonable measure of 
determining whether there is an adverse environmental effect since 
it was established considering ``effects on soils, water, crops, 
vegetation, man-made materials, animals, wildlife, weather, 
visibility and climate, damage to and deterioration of property, and 
hazards to transportation, as well as effects on economic values and 
on personal comfort and well-being.''
---------------------------------------------------------------------------

    Due to their well-documented potential to cause direct damage to 
terrestrial plants, we include two acid gases, HCl and HF, in the 
environmental screening analysis. According to the 2005 NEI, HCl and HF 
account for about 99 percent (on a mass basis) of the total acid gas 
HAP emitted by stationary sources in the U.S. In addition to the 
potential to cause direct damage to plants, high concentrations of HF 
in the air have been linked to fluorosis in livestock. Air 
concentrations of these HAP are already calculated as part of the human 
multipathway exposure and risk screening analysis using the HEM3-AERMOD 
air dispersion model, and we are able to use the air dispersion 
modeling results to estimate the potential for an adverse environmental 
effect.
    The EPA acknowledges that other HAP beyond the seven HAP discussed 
above may have the potential to cause adverse environmental effects. 
Therefore, the EPA may include other relevant HAP in its environmental 
risk

[[Page 60251]]

screening in the future, as modeling science and resources allow. The 
EPA invites comment on the extent to which other HAP emitted by the 
source category may cause adverse environmental effects. Such 
information should include references to peer-reviewed ecological 
effects benchmarks that are of sufficient quality for making regulatory 
decisions, as well as information on the presence of organisms located 
near facilities within the source category that such benchmarks 
indicate could be adversely affected.
c. Ecological Assessment Endpoints and Benchmarks for PB-HAP
    An important consideration in the development of the EPA's 
screening methodology is the selection of ecological assessment 
endpoints and benchmarks. Ecological assessment endpoints are defined 
by the ecological entity (e.g., aquatic communities including fish and 
plankton) and its attributes (e.g., frequency of mortality). Ecological 
assessment endpoints can be established for organisms, populations, 
communities or assemblages, and ecosystems.
    For PB-HAP (other than lead compounds), we evaluated the following 
community-level ecological assessment endpoints to screen for organisms 
directly exposed to HAP in soils, sediment and water:
     Local terrestrial communities (i.e., soil invertebrates, 
plants) and populations of small birds and mammals that consume soil 
invertebrates exposed to PB-HAP in the surface soil.
     Local benthic (i.e., bottom sediment dwelling insects, 
amphipods, isopods and crayfish) communities exposed to PB-HAP in 
sediment in nearby water bodies.
     Local aquatic (water-column) communities (including fish 
and plankton) exposed to PB-HAP in nearby surface waters.
    For PB-HAP (other than lead compounds), we also evaluated the 
following population-level ecological assessment endpoint to screen for 
indirect HAP exposures of top consumers via the bioaccumulation of HAP 
in food chains.
     Piscivorous (i.e., fish-eating) wildlife consuming PB-HAP-
contaminated fish from nearby water bodies.
    For cadmium compounds, dioxins/furans, POM and mercury, we 
identified the available ecological benchmarks for each assessment 
endpoint. An ecological benchmark represents a concentration of HAP 
(e.g., 0.77 ug of HAP per liter of water) that has been linked to a 
particular environmental effect level (e.g., a no-observed-adverse-
effect level (NOAEL)) through scientific study. For PB-HAP we 
identified, where possible, ecological benchmarks at the following 
effect levels:
    Probable effect levels (PEL): Level above which adverse effects are 
expected to occur frequently.
    Lowest-observed-adverse-effect level (LOAEL): The lowest exposure 
level tested at which there are biologically significant increases in 
frequency or severity of adverse effects.
    No-observed-adverse-effect levels (NOAEL): The highest exposure 
level tested at which there are no biologically significant increases 
in the frequency or severity of adverse effect.
    We established a hierarchy of preferred benchmark sources to allow 
selection of benchmarks for each environmental HAP at each ecological 
assessment endpoint. In general, the EPA sources that are used at a 
programmatic level (e.g., Office of Water, Superfund Program) were 
used, if available. If not, the EPA benchmarks used in regional 
programs (e.g., Superfund) were used. If benchmarks were not available 
at a programmatic or regional level, we used benchmarks developed by 
other federal agencies (e.g., National Oceanic and Atmospheric 
Administration (NOAA)) or state agencies.
    Benchmarks for all effect levels are not available for all PB-HAP 
and assessment endpoints. In cases where multiple effect levels were 
available for a particular PB-HAP and assessment endpoint, we use all 
of the available effect levels to help us to determine whether 
ecological risks exist and, if so, whether the risks could be 
considered significant and widespread.
d. Ecological Assessment Endpoints and Benchmarks for Acid Gases
    The environmental screening analysis also evaluated potential 
damage and reduced productivity of plants due to direct exposure to 
acid gases in the air. For acid gases, we evaluated the following 
ecological assessment endpoint:
     Local terrestrial plant communities with foliage exposed 
to acidic gaseous HAP in the air.
    The selection of ecological benchmarks for the effects of acid 
gases on plants followed the same approach as for PB-HAP (i.e., we 
examine all of the available benchmarks). For HCl, the EPA identified 
chronic benchmark concentrations. We note that the benchmark for 
chronic HCl exposure to plants is greater than the reference 
concentration for chronic inhalation exposure for human health. This 
means that where the EPA includes regulatory requirements to prevent an 
exceedance of the reference concentration for human health, additional 
analyses for adverse environmental effects of HCl would not be 
necessary.
    For HF, the EPA identified chronic benchmark concentrations for 
plants and evaluated chronic exposures to plants in the screening 
analysis. High concentrations of HF in the air have also been linked to 
fluorosis in livestock. However, the HF concentrations at which 
fluorosis in livestock occur are higher than those at which plant 
damage begins. Therefore, the benchmarks for plants are protective of 
both plants and livestock.
e. Screening Methodology
    For the environmental risk screening analysis, the EPA first 
determined whether any facilities in the ferroalloys production source 
category sources emitted any of the seven environmental HAP. For the 
ferroalloys production source category, we identified emissions of five 
of the PB HAP (cadmium, mercury, lead compounds, dioxins and polycyclic 
organic matter) and one acid gas (HCl).
    Because one or more of the seven environmental HAP evaluated are 
emitted by the facilities in the source category, we proceeded to the 
second step of the evaluation.
f. PB-HAP Methodology
    For cadmium, mercury, POM and dioxins/furans, the environmental 
screening analysis consists of two tiers, while lead compounds are 
analyzed differently as discussed earlier. In the first tier, we 
determined whether the maximum facility-specific emission rates of each 
of the emitted environmental HAP were large enough to create the 
potential for adverse environmental effects under reasonable worst-case 
environmental conditions. These are the same environmental conditions 
used in the human multipathway exposure and risk screening analysis.
    To facilitate this step, TRIM.FaTE was run for each PB-HAP under 
hypothetical environmental conditions designed to provide 
conservatively high HAP concentrations. The model was set to maximize 
runoff from terrestrial parcels into the modeled lake, which in turn, 
maximized the chemical concentrations in the water, the sediments and 
the fish. The resulting media concentrations were then used to back-
calculate a screening level emission rate that corresponded to the

[[Page 60252]]

relevant exposure benchmark concentration value for each assessment 
endpoint. To assess emissions from a facility, the reported emission 
rate for each PB-HAP was compared to the screening level emission rate 
for that PB-HAP for each assessment endpoint. If emissions from a 
facility do not exceed the Tier I screening level, the facility 
``passes'' the screen, and therefore, is not evaluated further under 
the screening approach. If emissions from a facility exceed the Tier I 
screening level, we evaluate the facility further in Tier II.
    In Tier II of the environmental screening analysis, the emission 
rate screening levels are adjusted to account for local meteorology and 
the actual location of lakes in the vicinity of facilities that did not 
pass the Tier I screen. The modeling domain for each facility in the 
tier II analysis consists of eight octants. Each octant contains 5 
modeled soil concentrations at various distances from the facility (5 
soil concentrations x 8 octants = total of 40 soil concentrations per 
facility) and 1 lake with modeled concentrations for water, sediment 
and fish tissue. In the tier II environmental risk screening analysis, 
the 40 soil concentration points are averaged to obtain an average soil 
concentration for each facility for each PB-HAP. For the water, 
sediment and fish tissue concentrations, the highest value for each 
facility for each pollutant is used. If emission concentrations from a 
facility do not exceed the Tier II screening levels, the facility 
passes the screen and typically is not evaluated further. If emissions 
from a facility exceed the Tier II screening level, the facility does 
not pass the screen and, therefore, may have the potential to cause 
adverse environmental effects. Such facilities are evaluated further to 
investigate factors such as the magnitude and characteristics of the 
area of exceedance.
g. Acid Gas Methodology
    The environmental screening analysis evaluates the potential 
phytotoxicity and reduced productivity of plants due to chronic 
exposure to acid gases. The environmental risk screening methodology 
for acid gases is a single-tier screen that compares the average off-
site ambient air concentration over the modeling domain to ecological 
benchmarks for each of the acid gases. Because air concentrations are 
compared directly to the ecological benchmarks, emission-based 
screening levels are not calculated for acid gases as they are in the 
ecological risk screening methodology for PB-HAPs.
    For purposes of ecological risk screening, the EPA identifies a 
potential for adverse environmental effects to plant communities from 
exposure to acid gases when the average concentration of the HAP around 
a facility exceeds the LOAEL ecological benchmark. In such cases, we 
further investigate factors such as the magnitude and characteristics 
of the area of exceedance (e.g., land use of exceedance area, size of 
exceedance area) to determine if there is an adverse environmental 
effect. For further information on the environmental screening analysis 
approach, see the Residual Risk Assessment for the Ferroalloys 
Production Source Category in Support of the September 2014 
Supplemental Proposal, which is available in the docket for this 
action.
7. How did we conduct facility-wide assessments?
    To put the source category risks in context, we typically examine 
the risks from the entire ``facility,'' where the facility includes all 
HAP-emitting operations within a contiguous area and under common 
control. In other words, we examine the HAP emissions not only from the 
source category of interest, but also emissions of HAP from all other 
emissions sources at the facility for which we have data. However, for 
the Ferroalloys Production source category, we did not identify other 
HAP emissions sources located at these facilities. Thus, we did not 
perform a separate facility wide risk assessment.
8. How did we consider uncertainties in risk assessment?
    In the Benzene NESHAP, we concluded that risk estimation 
uncertainty should be considered in our decision-making under the ample 
margin of safety framework. Uncertainty and the potential for bias are 
inherent in all risk assessments, including those performed for this 
proposal. Although uncertainty exists, we believe that our approach, 
which used conservative tools and assumptions, ensures that our 
decisions are health protective and environmentally protective. A brief 
discussion of the uncertainties in the RTR emissions dataset, 
dispersion modeling, inhalation exposure estimates and dose-response 
relationships follows below. A more thorough discussion of these 
uncertainties is included in the Revised Development of the RTR 
Emissions Dataset for the Ferroalloys Production Source Category for 
the 2014 Supplemental Proposal (Emissions Memo) and the other 
uncertainties are described in more detail in the Residual Risk 
Assessment for the Ferroalloys Production Source Category in Support of 
the September 2014 Supplemental Proposal, which is available in the 
docket for this action.
a. Uncertainties in the RTR Emissions Dataset
    Although the development of the RTR emissions dataset involved 
quality assurance/quality control processes, the accuracy of emissions 
values will vary depending on the source of the data, the degree to 
which data are incomplete or missing, the degree to which assumptions 
made to complete the datasets are accurate, errors in emission 
estimates and other factors. The emission estimates considered in this 
analysis generally are annual totals for certain years, and they do not 
reflect short-term fluctuations during the course of a year or 
variations from year to year. The estimates of peak hourly emission 
rates for the acute effects screening assessment were based on an 
emission adjustment factor applied to the average annual hourly 
emission rates, which are intended to account for emission fluctuations 
due to normal facility operations.
    As described above and in the emissions technical document, we 
gathered a substantial amount of emissions test data for the stack 
emissions from both facilities. Therefore, the level of uncertainty in 
the estimates of HAP emissions from the stacks is relatively low. 
Regarding fugitive emissions, we lack direct quantitative measurements 
of these emissions, therefore, we had to rely on available emissions 
factors and other technical information to derive the best estimates of 
emissions for these emissions. To estimate these fugitive emissions, we 
relied on information and observations gathered through several site 
visits by the EPA technical experts, reviewed and evaluated all 
available emissions factors and analyzed other relevant information 
such as the measured ratios of HAP metals to particulate matter, 
estimated capture efficiencies of the various ventilation hoods 
currently used to capture and control some of the fugitive emissions 
and the production rates for various products. Based on this 
information, we have derived the best estimates of fugitive emissions 
from these sources. Details are described in the Emissions Memo, which 
is available in the docket for this action. Nevertheless, there are 
still some uncertainties regarding the precise quantities of fugitive 
HAP being emitted from these plants.

[[Page 60253]]

b. Uncertainties in Dispersion Modeling
    We recognize there is uncertainty in ambient concentration 
estimates associated with any model, including the EPA's recommended 
regulatory dispersion model, AERMOD. In using a model to estimate 
ambient pollutant concentrations, the user chooses certain options to 
apply. For RTR assessments, we select some model options that have the 
potential to overestimate ambient air concentrations (e.g., not 
including plume depletion or pollutant transformation). We select other 
model options that have the potential to underestimate ambient impacts 
(e.g., not including building downwash). Other options that we select 
have the potential to either under- or overestimate ambient levels 
(e.g., meteorology and receptor locations). On balance, considering the 
directional nature of the uncertainties commonly present in ambient 
concentrations estimated by dispersion models, the approach we apply in 
the RTR assessments should yield unbiased estimates of ambient HAP 
concentrations.
c. Uncertainties in Inhalation Exposure
    The EPA did not include the effects of human mobility on exposures 
in the assessment. Specifically, short-term mobility and long-term 
mobility between census blocks in the modeling domain were not 
considered.\32\ The approach of not considering short or long-term 
population mobility does not bias the estimate of the theoretical MIR 
(by definition), nor does it affect the estimate of cancer incidence 
because the total population number remains the same. It does, however, 
affect the shape of the distribution of individual risks across the 
affected population, shifting it toward higher estimated individual 
risks at the upper end and reducing the number of people estimated to 
be at lower risks, thereby increasing the estimated number of people at 
specific high risk levels (e.g., 1-in-10 thousand or 1-in-1 million).
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    \32\ Short-term mobility is movement from one micro-environment 
to another over the course of hours or days. Long-term mobility is 
movement from one residence to another over the course of a 
lifetime.
---------------------------------------------------------------------------

    In addition, the assessment predicted the chronic exposures at the 
centroid of each populated census block as surrogates for the exposure 
concentrations for all people living in that block. Using the census 
block centroid to predict chronic exposures tends to over-predict 
exposures for people in the census block who live farther from the 
facility and under-predict exposures for people in the census block who 
live closer to the facility. Thus, using the census block centroid to 
predict chronic exposures may lead to a potential understatement or 
overstatement of the true maximum impact, but is an unbiased estimate 
of average risk and incidence. We reduce this uncertainty by analyzing 
large census blocks near facilities using aerial imagery and adjusting 
the location of the block centroid to better represent the population 
in the block, as well as adding additional receptor locations where the 
block population is not well represented by a single location.
    The assessment evaluates the cancer inhalation risks associated 
with pollutant exposures over a 70-year period, which is the assumed 
lifetime of an individual. In reality, both the length of time that 
modeled emission sources at facilities actually operate (i.e., more or 
less than 70 years) and the domestic growth or decline of the modeled 
industry (i.e., the increase or decrease in the number or size of 
domestic facilities) will influence the future risks posed by a given 
source or source category. Depending on the characteristics of the 
industry, these factors will, in most cases, result in an overestimate 
both in individual risk levels and in the total estimated number of 
cancer cases. However, in the unlikely scenario where a facility 
maintains, or even increases, its emissions levels over a period of 
more than 70 years, residents live beyond 70 years at the same 
location, and the residents spend most of their days at that location, 
then the cancer inhalation risks could potentially be underestimated. 
However, annual cancer incidence estimates from exposures to emissions 
from these sources would not be affected by the length of time an 
emissions source operates.
    The exposure estimates used in these analyses assume chronic 
exposures to ambient (outdoor) levels of pollutants. Because most 
people spend the majority of their time indoors, actual exposures may 
not be as high, depending on the characteristics of the pollutants 
modeled. For many of the HAP, indoor levels are roughly equivalent to 
ambient levels, but for very reactive pollutants or larger particles, 
indoor levels are typically lower. This factor has the potential to 
result in an overestimate of 25 to 30 percent of exposures.\33\
---------------------------------------------------------------------------

    \33\ U.S. EPA. National-Scale Air Toxics Assessment for 1996. 
(EPA 453/R-01-003; January 2001; page 85.)
---------------------------------------------------------------------------

    In addition to the uncertainties highlighted above, there are 
several factors specific to the acute exposure assessment that the EPA 
conducts as part of the risk review under section 112 of the CAA that 
should be highlighted. The accuracy of an acute inhalation exposure 
assessment depends on the simultaneous occurrence of independent 
factors that may vary greatly, such as hourly emissions rates, 
meteorology and the presence of humans at the location of the maximum 
concentration. In the acute screening assessment that we conduct under 
the RTR program, we assume that peak emissions from the source category 
and worst-case meteorological conditions co-occur, thus resulting in 
maximum ambient concentrations. These two events are unlikely to occur 
at the same time, making these assumptions conservative. We then 
include the additional assumption that a person is located at this 
point during this same time period. For this source category, these 
assumptions would tend to be worst-case actual exposures as it is 
unlikely that a person would be located at the point of maximum 
exposure during the time when peak emissions and worst-case 
meteorological conditions occur simultaneously.
d. Uncertainties in Dose-Response Relationships
    There are uncertainties inherent in the development of the dose-
response values used in our risk assessments for cancer effects from 
chronic exposures and non-cancer effects from both chronic and acute 
exposures. Some uncertainties may be considered quantitatively, and 
others generally are expressed in qualitative terms. We note as a 
preface to this discussion a point on dose-response uncertainty that is 
brought out in the EPA's 2005 Cancer Guidelines; namely, that ``the 
primary goal of EPA actions is protection of human health; accordingly, 
as an Agency policy, risk assessment procedures, including default 
options that are used in the absence of scientific data to the 
contrary, should be health protective'' (EPA 2005 Cancer Guidelines, 
pages 1-7). This is the approach followed here as summarized in the 
next several paragraphs. A complete detailed discussion of 
uncertainties and variability in dose-response relationships is given 
in the Residual Risk Assessment for the Ferroalloys Production Source 
Category in Support of the September 2014 Supplemental Proposal, which 
is available in the docket for this action.
    Cancer URE values used in our risk assessments are those that have 
been developed to generally provide an upper bound estimate of risk. 
That is, they represent a ``plausible upper limit to the

[[Page 60254]]

true value of a quantity'' (although this is usually not a true 
statistical confidence limit).\34\ In some circumstances, the true risk 
could be as low as zero; however, in other circumstances the risk could 
be greater.\35\ When developing an upper bound estimate of risk and to 
provide risk values that do not underestimate risk, health-protective 
default approaches are generally used. To err on the side of ensuring 
adequate health protection, the EPA typically uses the upper bound 
estimates rather than lower bound or central tendency estimates in our 
risk assessments, an approach that may have limitations for other uses 
(e.g., priority-setting or expected benefits analysis).
---------------------------------------------------------------------------

    \34\ IRIS glossary (http://www.epa.gov/NCEA/iris/help_gloss.htm).
    \35\ An exception to this is the URE for benzene, which is 
considered to cover a range of values, each end of which is 
considered to be equally plausible and which is based on maximum 
likelihood estimates.
---------------------------------------------------------------------------

    Chronic non-cancer RfC and reference dose (RfD) values represent 
chronic exposure levels that are intended to be health-protective 
levels. Specifically, these values provide an estimate (with 
uncertainty spanning perhaps an order of magnitude) of a continuous 
inhalation exposure (RfC) or a daily oral exposure (RfD) to the human 
population (including sensitive subgroups) that is likely to be without 
an appreciable risk of deleterious effects during a lifetime. To derive 
values that are intended to be ``without appreciable risk,'' the 
methodology relies upon an uncertainty factor (UF) approach (U.S. EPA, 
1993, 1994) which considers uncertainty, variability and gaps in the 
available data. The UF are applied to derive reference values that are 
intended to protect against appreciable risk of deleterious effects. 
The UF are commonly default values,\36\ e.g., factors of 10 or 3, used 
in the absence of compound-specific data; where data are available, UF 
may also be developed using compound-specific information. When data 
are limited, more assumptions are needed and more UF are used. Thus, 
there may be a greater tendency to overestimate risk in the sense that 
further study might support development of reference values that are 
higher (i.e., less potent) because fewer default assumptions are 
needed. However, for some pollutants, it is possible that risks may be 
underestimated.
---------------------------------------------------------------------------

    \36\ According to the NRC report, Science and Judgment in Risk 
Assessment (NRC, 1994) ``[Default] options are generic approaches, 
based on general scientific knowledge and policy judgment, that are 
applied to various elements of the risk assessment process when the 
correct scientific model is unknown or uncertain.'' The 1983 NRC 
report, Risk Assessment in the Federal Government: Managing the 
Process, defined default option as ``the option chosen on the basis 
of risk assessment policy that appears to be the best choice in the 
absence of data to the contrary'' (NRC, 1983a, p. 63). Therefore, 
default options are not rules that bind the Agency; rather, the 
Agency may depart from them in evaluating the risks posed by a 
specific substance when it believes this to be appropriate. In 
keeping with EPA's goal of protecting public health and the 
environment, default assumptions are used to ensure that risk to 
chemicals is not underestimated (although defaults are not intended 
to overtly overestimate risk). See EPA, 2004, An Examination of EPA 
Risk Assessment Principles and Practices, EPA/100/B-04/001 available 
at: http://www.epa.gov/osa/pdfs/ratf-final.pdf.
---------------------------------------------------------------------------

    While collectively termed ``UF,'' these factors account for a 
number of different quantitative considerations when using observed 
animal (usually rodent) or human toxicity data in the development of 
the RfC. The UF are intended to account for: (1) Variation in 
susceptibility among the members of the human population (i.e., inter-
individual variability); (2) uncertainty in extrapolating from 
experimental animal data to humans (i.e., interspecies differences); 
(3) uncertainty in extrapolating from data obtained in a study with 
less-than-lifetime exposure (i.e., extrapolating from sub-chronic to 
chronic exposure); (4) uncertainty in extrapolating the observed data 
to obtain an estimate of the exposure associated with no adverse 
effects; and (5) uncertainty when the database is incomplete or there 
are problems with the applicability of available studies.
    Many of the UF used to account for variability and uncertainty in 
the development of acute reference values are quite similar to those 
developed for chronic durations, but they more often use individual UF 
values that may be less than 10. The UF are applied based on chemical-
specific or health effect-specific information (e.g., simple irritation 
effects do not vary appreciably between human individuals, hence a 
value of 3 is typically used), or based on the purpose for the 
reference value (see the following paragraph). The UF applied in acute 
reference value derivation include: (1) Heterogeneity among humans; (2) 
uncertainty in extrapolating from animals to humans; (3) uncertainty in 
lowest observed adverse effect (exposure) level to no observed adverse 
effect (exposure) level adjustments; and (4) uncertainty in accounting 
for an incomplete database on toxic effects of potential concern. 
Additional adjustments are often applied to account for uncertainty in 
extrapolation from observations at one exposure duration (e.g., 4 
hours) to derive an acute reference value at another exposure duration 
(e.g., 1 hour).
    Not all acute reference values are developed for the same purpose 
and care must be taken when interpreting the results of an acute 
assessment of human health effects relative to the reference value or 
values being exceeded. Where relevant to the estimated exposures, the 
lack of short-term dose-response values at different levels of severity 
should be factored into the risk characterization as potential 
uncertainties.
    Although every effort is made to identify appropriate human health 
effect dose-response assessment values for all pollutants emitted by 
the sources in this risk assessment, some HAP emitted by this source 
category are lacking dose-response assessments. Accordingly, these 
pollutants cannot be included in the quantitative risk assessment, 
which could result in quantitative estimates understating HAP risk. As 
we state above in section III.A.3, based on a recent in-depth 
examination of the available acute value for nickel (California EPA's 
acute (1-hour) REL), we have concluded that this value is not 
appropriate for our regulatory needs in characterizing the potential 
for acute health risks. This conclusion takes into account the effect 
on which the acute REL is based, aspects of the methodology used in its 
derivation, and how this assessment stands in comparison to other 
comprehensive toxicological assessments which considered the broader 
nickel health effects database. Also, there are no AEGL-1 or -2 or 
ERPG-1 or -2 values available to use in this acute risk assessment. 
Therefore, we will not include nickel in our acute analysis for this 
source category or in future assessments unless and until an 
appropriate value becomes available.
    To help to alleviate this potential underestimate, where we 
conclude similarity with a HAP for which a dose-response assessment 
value is available, we use that value as a surrogate for the assessment 
of the HAP for which no value is available. To the extent use of 
surrogates indicates appreciable risk, we may identify a need to 
increase priority for new IRIS assessment of that substance. We 
additionally note that, generally speaking, HAP of greatest concern due 
to environmental exposures and hazard are those for which dose-response 
assessments have been performed, reducing the likelihood of 
understating risk. Further, HAP not included in the quantitative 
assessment are assessed qualitatively and considered in the risk 
characterization that informs the risk management decisions, including 
with regard to consideration of HAP reductions achieved by various 
control options.

[[Page 60255]]

    For a group of compounds that are unspeciated (e.g., glycol 
ethers), we conservatively use the most protective reference value of 
an individual compound in that group to estimate risk. Similarly, for 
an individual compound in a group (e.g., ethylene glycol diethyl ether) 
that does not have a specified reference value, we also apply the most 
protective reference value from the other compounds in the group to 
estimate risk.
e. Uncertainties in the Multipathway Assessment
    For each source category, we generally rely on site-specific levels 
of PB-HAP emissions to determine whether a refined assessment of the 
impacts from multipathway exposures is necessary. This determination is 
based on the results of a two-tiered screening analysis that relies on 
the outputs from models that estimate environmental pollutant 
concentrations and human exposures for four PB-HAP. Two important types 
of uncertainty associated with the use of these models in RTR risk 
assessments and inherent to any assessment that relies on environmental 
modeling are model uncertainty and input uncertainty.\37\ Model 
uncertainty concerns whether the selected models are appropriate for 
the assessment being conducted and whether they adequately represent 
the actual processes that might occur for that situation. An example of 
model uncertainty is the question of whether the model adequately 
describes the movement of a pollutant through the soil. This type of 
uncertainty is difficult to quantify. However, based on feedback 
received from previous EPA Science Advisory Board reviews and other 
reviews, we are confident that the models used in the screen are 
appropriate and state-of-the-art for the multipathway risk assessments 
conducted in support of RTR.
---------------------------------------------------------------------------

    \37\ In the context of this discussion, the term ``uncertainty'' 
as it pertains to exposure and risk encompasses both variability in 
the range of expected inputs and screening results due to existing 
spatial, temporal, and other factors, as well as uncertainty in 
being able to accurately estimate the true result.
---------------------------------------------------------------------------

    Input uncertainty is concerned with how accurately the models have 
been configured and parameterized for the assessment at hand. For Tier 
I of the multipathway screen, we configured the models to avoid 
underestimating exposure and risk. This was accomplished by selecting 
upper-end values from nationally-representative data sets for the more 
influential parameters in the environmental model, including selection 
and spatial configuration of the area of interest, lake location and 
size, meteorology, surface water and soil characteristics and structure 
of the aquatic food web. We also assume an ingestion exposure scenario 
and values for human exposure factors that represent reasonable maximum 
exposures.
    In Tier II of the multipathway assessment, we refine the model 
inputs to account for meteorological patterns in the vicinity of the 
facility versus using upper-end national values and we identify the 
actual location of lakes near the facility rather than the default lake 
location that we apply in Tier I. By refining the screening approach in 
Tier II to account for local geographical and meteorological data, we 
decrease the likelihood that concentrations in environmental media are 
overestimated, thereby increasing the usefulness of the screen. The 
assumptions and the associated uncertainties regarding the selected 
ingestion exposure scenario are the same for Tier I and Tier II.
    For both Tiers I and II of the multipathway assessment, our 
approach to addressing model input uncertainty is generally cautious. 
We choose model inputs from the upper end of the range of possible 
values for the influential parameters used in the models, and we assume 
that the exposed individual exhibits ingestion behavior that would lead 
to a high total exposure. This approach reduces the likelihood of not 
identifying high risks for adverse impacts.
    Despite the uncertainties, when individual pollutants or facilities 
do screen out, we are confident that the potential for adverse 
multipathway impacts on human health is very low. On the other hand, 
when individual pollutants or facilities do not screen out, it does not 
mean that multipathway impacts are significant, only that we cannot 
rule out that possibility and that a refined multipathway analysis for 
the site might be necessary to obtain a more accurate risk 
characterization for the source category.
    For further information on uncertainties and the Tier I and II 
screening methods, refer to the risk document Appendix 4, Technical 
Support Document for TRIM-Based Multipathway Tiered Screening 
Methodology for RTR.
    We also completed a refined multi-pathway assessment for this 
supplemental proposal. The refined assessment contains considerably 
less uncertainty compared to the Tier I and Tier II screens. 
Nevertheless, some uncertainties also exist with the refined 
assessments. The refined multi-pathway assessment and related 
uncertainties are described in detail in the risk document Appendix 10, 
Residual Risk Assessment for the Ferroalloys Production Source Category 
in Support of the September 2014 Supplemental Proposal, which is 
available in the docket for this action.
f. Uncertainties in the Environmental Risk Screening Assessment
    For each source category, we generally rely on site-specific levels 
of environmental HAP emissions to perform an environmental screening 
assessment. The environmental screening assessment is based on the 
outputs from models that estimate environmental HAP concentrations. The 
same models, specifically the TRIM.FaTE multipathway model and the 
AERMOD air dispersion model, are used to estimate environmental HAP 
concentrations for both the human multipathway screening analysis and 
for the environmental screening analysis. Therefore, both screening 
assessments have similar modeling uncertainties.
    Two important types of uncertainty associated with the use of these 
models in RTR environmental screening assessments--and inherent to any 
assessment that relies on environmental modeling--are model uncertainty 
and input uncertainty.\38\
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    \38\ In the context of this discussion, the term 
``uncertainty,'' as it pertains to exposure and risk assessment, 
encompasses both variability in the range of expected inputs and 
screening results due to existing spatial, temporal and other 
factors, as well as uncertainty in being able to accurately estimate 
the true result.
---------------------------------------------------------------------------

    Model uncertainty concerns whether the selected models are 
appropriate for the assessment being conducted and whether they 
adequately represent the movement and accumulation of environmental HAP 
emissions in the environment. For example, does the model adequately 
describe the movement of a pollutant through the soil? This type of 
uncertainty is difficult to quantify. However, based on feedback 
received from previous EPA Science Advisory Board reviews and other 
reviews, we are confident that the models used in the screen are 
appropriate and state-of-the-art for the environmental risk assessments 
conducted in support of our RTR analyses.
    Input uncertainty is concerned with how accurately the models have 
been configured and parameterized for the assessment at hand. For Tier 
I of the environmental screen for PB-HAP, we configured the models to 
avoid underestimating exposure and risk to reduce the likelihood that 
the results indicate the risks are lower than they actually are. This 
was accomplished by

[[Page 60256]]

selecting upper-end values from nationally-representative data sets for 
the more influential parameters in the environmental model, including 
selection and spatial configuration of the area of interest, the 
location and size of any bodies of water, meteorology, surface water 
and soil characteristics and structure of the aquatic food web. In Tier 
I, we used the maximum facility-specific emissions for the PB-HAP 
(other than lead compounds, which were evaluated by comparison to the 
secondary lead NAAQS) that were included in the environmental screening 
assessment and each of the media when comparing to ecological 
benchmarks. This is consistent with the conservative design of Tier I 
of the screen. In Tier II of the environmental screening analysis for 
PB-HAP, we refine the model inputs to account for meteorological 
patterns in the vicinity of the facility versus using upper-end 
national values, and we identify the locations of water bodies near the 
facility location. By refining the screening approach in Tier II to 
account for local geographical and meteorological data, we decrease the 
likelihood that concentrations in environmental media are 
overestimated, thereby increasing the usefulness of the screen. To 
better represent widespread impacts, the modeled soil concentrations 
are averaged in Tier II to obtain one average soil concentration value 
for each facility and for each PB-HAP. For PB-HAP concentrations in 
water, sediment and fish tissue, the highest value for each facility 
for each pollutant is used.
    For the environmental screening assessment for acid gases, we 
employ a single-tiered approach. We use the modeled air concentrations 
and compare those with ecological benchmarks.
    For both Tiers I and II of the environmental screening assessment, 
our approach to addressing model input uncertainty is generally 
cautious. We choose model inputs from the upper end of the range of 
possible values for the influential parameters used in the models, and 
we assume that the exposed individual exhibits ingestion behavior that 
would lead to a high total exposure. This approach reduces the 
likelihood of not identifying potential risks for adverse environmental 
impacts.
    Uncertainty also exists in the ecological benchmarks for the 
environmental risk screening analysis. We established a hierarchy of 
preferred benchmark sources to allow selection of benchmarks for each 
environmental HAP at each ecological assessment endpoint. In general, 
EPA benchmarks used at a programmatic level (e.g., Office of Water, 
Superfund Program) were used if available. If not, we used EPA 
benchmarks used in regional programs (e.g., Superfund Program). If 
benchmarks were not available at a programmatic or regional level, we 
used benchmarks developed by other agencies (e.g., NOAA) or by state 
agencies.
    In all cases (except for lead compounds, which were evaluated 
through a comparison to the NAAQS), we searched for benchmarks at the 
following three effect levels, as described in section III.A.6. of this 
notice:

    1. A no-effect level (i.e., NOAEL).
    2. Threshold-effect level (i.e., LOAEL).
    3. Probable effect level (i.e., PEL).

    For some ecological assessment endpoint/environmental HAP 
combinations, we could identify benchmarks for all three effect levels, 
but for most, we could not. In one case, where different agencies 
derived significantly different numbers to represent a threshold for 
effect, we included both. In several cases, only a single benchmark was 
available. In cases where multiple effect levels were available for a 
particular PB-HAP and assessment endpoint, we used all of the available 
effect levels to help us to determine whether risk exists and if the 
risks could be considered significant and widespread.
    The EPA evaluates the following seven HAP in the environmental risk 
screening assessment: Cadmium, dioxins/furans, POM, mercury (both 
inorganic mercury and methyl mercury), lead compounds, HCl and HF, 
where applicable. These seven HAP represent pollutants that can cause 
adverse impacts for plants and animals either through direct exposure 
to HAP in the air or through exposure to HAP that is deposited from the 
air onto soils and surface waters. These seven HAP also represent those 
HAP for which we can conduct a meaningful environmental risk screening 
assessment. For other HAP not included in our screening assessment, the 
model has not been parameterized such that it can be used for that 
purpose. In some cases, depending on the HAP, we may not have 
appropriate multipathway models that allow us to predict the 
concentration of that pollutant. The EPA acknowledges that other HAP 
beyond the seven HAP that we are evaluating may have the potential to 
cause adverse environmental effects and, therefore, the EPA may 
evaluate other relevant HAP in the future, as modeling science and 
resources allow.
    Further information on uncertainties and the Tier I and II 
screening methods is provided in Appendix 4 of the document ``Technical 
Support Document for TRIM-Based Multipathway Tiered Screening 
Methodology for RTR: Summary of Approach and Evaluation.'' Also, see 
the Residual Risk Assessment for the Ferroalloys Production Source 
Category in Support of the September 2014 Supplemental Proposal, 
available in the docket for this action.

B. How did we consider the risk results in making decisions for this 
supplemental proposal?

    As discussed in section II.A of this preamble, in evaluating and 
developing standards under section 112(f)(2), we apply a two-step 
process to address residual risk. In the first step, the EPA determines 
whether risks are acceptable. This determination ``considers all health 
information, including risk estimation uncertainty, and includes a 
presumptive limit on maximum individual lifetime [cancer] risk (MIR) 
\39\ of approximately [1-in-10 thousand] [i.e., 100-in-1 million].'' 54 
FR 38045, September 14, 1989. If risks are unacceptable, the EPA must 
determine the emissions standards necessary to bring risks to an 
acceptable level without considering costs. In the second step of the 
process, the EPA considers whether the emissions standards provide an 
ample margin of safety ``in consideration of all health information, 
including the number of persons at risk levels higher than 
approximately 1-in-1 million, as well as other relevant factors, 
including costs and economic impacts, technological feasibility, and 
other factors relevant to each particular decision.'' Id. The EPA must 
promulgate emission standards necessary to provide an ample margin of 
safety.
---------------------------------------------------------------------------

    \39\ Although defined as ``maximum individual risk,'' MIR refers 
only to cancer risk. MIR, one metric for assessing cancer risk, is 
the estimated risk were an individual exposed to the maximum level 
of a pollutant for a lifetime.
---------------------------------------------------------------------------

    In past residual risk actions, the EPA considered a number of human 
health risk metrics associated with emissions from the categories under 
review, including the MIR, the number of persons in various risk 
ranges, cancer incidence, the maximum non-cancer HI and the maximum 
acute non-cancer hazard. See, e.g., 72 FR 25138, May 3, 2007; 71 FR 
42724, July 27, 2006. The EPA considered this health information for 
both actual and allowable emissions. See, e.g., 75 FR 65068, October 
21, 2010; 75 FR 80220, December 21, 2010; 76 FR 29032, May 19, 2011. 
The EPA also discussed risk estimation uncertainties

[[Page 60257]]

and considered the uncertainties in the determination of acceptable 
risk and ample margin of safety in these past actions. The EPA 
considered this same type of information in support of this action.
    The agency is considering these various measures of health 
information to inform our determinations of risk acceptability and 
ample margin of safety under CAA section 112(f). As explained in the 
Benzene NESHAP, ``the first step judgment on acceptability cannot be 
reduced to any single factor'' and thus ``[t]he Administrator believes 
that the acceptability of risk under [previous] section 112 is best 
judged on the basis of a broad set of health risk measures and 
information.'' 54 FR 38046, September 14, 1989. Similarly, with regard 
to the ample margin of safety determination, ``the Agency again 
considers all of the health risk and other health information 
considered in the first step. Beyond that information, additional 
factors relating to the appropriate level of control will also be 
considered, including cost and economic impacts of controls, 
technological feasibility, uncertainties, and any other relevant 
factors.'' Id.
    The Benzene NESHAP approach provides flexibility regarding factors 
the EPA may consider in making determinations and how the EPA may weigh 
those factors for each source category. In responding to comment on our 
policy under the Benzene NESHAP, the EPA explained that:

    ``[t]he policy chosen by the Administrator permits consideration 
of multiple measures of health risk. Not only can the MIR figure be 
considered, but also incidence, the presence of non-cancer health 
effects, and the uncertainties of the risk estimates. In this way, 
the effect on the most exposed individuals can be reviewed as well 
as the impact on the general public. These factors can then be 
weighed in each individual case. This approach complies with the 
Vinyl Chloride mandate that the Administrator ascertain an 
acceptable level of risk to the public by employing [her] expertise 
to assess available data. It also complies with the Congressional 
intent behind the CAA, which did not exclude the use of any 
particular measure of public health risk from the EPA's 
consideration with respect to CAA section 112 regulations, and 
thereby implicitly permits consideration of any and all measures of 
health risk which the Administrator, in [her] judgment, believes are 
appropriate to determining what will `protect the public health'.''

See 54 FR at 38057, September 14, 1989. Thus, the level of the MIR is 
only one factor to be weighed in determining acceptability of risks. 
The Benzene NESHAP explained that ``an MIR of approximately one in 10 
thousand should ordinarily be the upper end of the range of 
acceptability. As risks increase above this benchmark, they become 
presumptively less acceptable under CAA section 112, and would be 
weighed with the other health risk measures and information in making 
an overall judgment on acceptability. Or, the Agency may find, in a 
particular case, that a risk that includes MIR less than the 
presumptively acceptable level is unacceptable in the light of other 
health risk factors.'' Id. at 38045. Similarly, with regard to the 
ample margin of safety analysis, the EPA stated in the Benzene NESHAP 
that: ``EPA believes the relative weight of the many factors that can 
be considered in selecting an ample margin of safety can only be 
determined for each specific source category. This occurs mainly 
because technological and economic factors (along with the health-
related factors) vary from source category to source category.'' Id. at 
38061. We also consider the uncertainties associated with the various 
risk analyses, as discussed earlier in this preamble, in our 
determinations of acceptability and ample margin of safety.
    The EPA notes that it has not considered certain health information 
to date in making residual risk determinations. At this time, we do not 
attempt to quantify those HAP risks that may be associated with 
emissions from other facilities that do not include the source 
categories in question, mobile source emissions, natural source 
emissions, persistent environmental pollution or atmospheric 
transformation in the vicinity of the sources in these categories.
    The agency understands the potential importance of considering an 
individual's total exposure to HAP in addition to considering exposure 
to HAP emissions from the source category and facility. We recognize 
that such consideration may be particularly important when assessing 
non-cancer risks, where pollutant-specific exposure health reference 
levels (e.g., RfCs) are based on the assumption that thresholds exist 
for adverse health effects. For example, the agency recognizes that, 
although exposures attributable to emissions from a source category or 
facility alone may not indicate the potential for increased risk of 
adverse non-cancer health effects in a population, the exposures 
resulting from emissions from the facility in combination with 
emissions from all of the other sources (e.g., other facilities) to 
which an individual is exposed may be sufficient to result in increased 
risk of adverse non-cancer health effects. In May 2010, the SAB advised 
the EPA ``that RTR assessments will be most useful to decision makers 
and communities if results are presented in the broader context of 
aggregate and cumulative risks, including background concentrations and 
contributions from other sources in the area.'' \40\
---------------------------------------------------------------------------

    \40\ EPA's responses to this and all other key recommendations 
of the SAB's advisory on RTR risk assessment methodologies (which is 
available at: http://yosemite.epa.gov/sab/sabproduct.nsf/
4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-unsigned.pdf) 
are outlined in a memo to this rulemaking docket from David Guinnup 
entitled, EPA's Actions in Response to the Key Recommendations of 
the SAB Review of RTR Risk Assessment Methodologies.
---------------------------------------------------------------------------

    In response to the SAB recommendations, the EPA is incorporating 
cumulative risk analyses into its RTR risk assessments, including those 
reflected in this proposal. The agency is: (1) Conducting facility-wide 
assessments, which include source category emission points as well as 
other emission points within the facilities; (2) considering sources in 
the same category whose emissions result in exposures to the same 
individuals; and (3) for some persistent and bioaccumulative 
pollutants, analyzing the ingestion route of exposure. In addition, the 
RTR risk assessments have always considered aggregate cancer risk from 
all carcinogens and aggregate non-cancer hazard indices from all non-
carcinogens affecting the same target organ system.
    Although we are interested in placing source category and facility-
wide HAP risks in the context of total HAP risks from all sources 
combined in the vicinity of each source, we are concerned about the 
uncertainties of doing so. Because of the contribution to total HAP 
risk from emission sources other than those that we have studied in 
depth during this RTR review, such estimates of total HAP risks would 
have significantly greater associated uncertainties than the source 
category or facility-wide estimates. Such aggregate or cumulative 
assessments would compound those uncertainties, making the assessments 
too unreliable.

C. How did we perform the technology review?

    Our technology review focused on the identification and evaluation 
of developments in practices, processes and control technologies that 
have occurred since the MACT standards were promulgated. Where we 
identified such developments, in order to inform our decision of 
whether it is ``necessary'' to revise the emissions standards, we 
analyzed the technical feasibility of applying these developments and 
the estimated costs,

[[Page 60258]]

energy implications, non-air environmental impacts, as well as 
considering the emission reductions. We also considered the 
appropriateness of applying controls to new sources versus retrofitting 
existing sources.
    Based on our analyses of the available data and information, we 
identified potential developments in practices, processes and control 
technologies. For this exercise, we considered any of the following to 
be a ``development'':
     Any add-on control technology or other equipment that was 
not identified and considered during development of the original MACT 
standards.
     Any improvements in add-on control technology or other 
equipment (that were identified and considered during development of 
the original MACT standards) that could result in additional emissions 
reduction.
     Any work practice or operational procedure that was not 
identified or considered during development of the original MACT 
standards.
     Any process change or pollution prevention alternative 
that could be broadly applied to the industry and that was not 
identified or considered during development of the original MACT 
standards.
     Any significant changes in the cost (including cost 
effectiveness) of applying controls (including controls the EPA 
considered during the development of the original MACT standards).
    We reviewed a variety of data sources in our investigation of 
potential practices, processes or controls to consider. Among the 
sources we reviewed were the NESHAP for various industries that were 
promulgated since the MACT standards being reviewed in this action. We 
reviewed the regulatory requirements and/or technical analyses 
associated with these regulatory actions to identify any practices, 
processes and control technologies considered in these efforts that 
could be applied to emission sources in the Ferroalloys Production 
source category, as well as the costs, non-air impacts and energy 
implications associated with the use of these technologies. 
Additionally, we requested information from facilities regarding 
developments in practices, processes or control technology. Finally, we 
reviewed information from other sources, such as state and/or local 
permitting agency databases and industry-supported databases.
    For the 2011 proposal, our technology review focused on the 
identification and evaluation of developments in practices, processes 
and control technologies that have occurred since the 1999 NESHAP was 
promulgated. In cases where the technology review identified such 
developments, we conducted an analysis of the technical feasibility of 
applying these developments, along with the estimated impacts (costs, 
emissions reductions, risk reductions, etc.) of applying these 
developments. We then made decisions on whether it is necessary to 
propose amendments to the 1999 NESHAP to require any of the identified 
developments. Based on our analyses of the data and information 
collected by the 2010 ICR and our general understanding of the industry 
and other available information on potential controls for this 
industry, we identified several potential developments in practices, 
processes and control technologies.
    Based on our technology review for the 2011 proposed rule, we 
determined that there had been advances in emissions control measures 
since the Ferroalloys Production NESHAP was originally promulgated in 
1999. Based on that review, we proposed lower PM emissions limits for 
the process vents because we determined that the existing add-on 
control devices (baghouses and wet venture scrubbers) were achieving 
better control than that reflected by the emissions limits in the 1999 
MACT rule. Furthermore, based on that previous technology review, to 
reduce fugitive process emissions, in 2011 we proposed a requirement 
for sources to enclose the furnace building, prevent the fugitive 
emissions from being released to the atmosphere by maintaining the 
furnace building under negative pressure and collect and duct those 
fugitive emissions to a control device. We proposed that approach in 
2011, because at that time, we believed it represented a technically-
feasible cost-effective advance in emissions control since the 
Ferroalloys Production NESHAP was originally promulgated in 1999. 
Additional details regarding the previously-conducted technology review 
can be found in the Technology Review for Ferroalloys Production Source 
Category (Docket No. EPA-HQ-OAR-2010-0895-0044), which is available in 
the docket and are discussed in the preamble to the 2011 proposal (76 
FR 72508). However, we received significant adverse public comments 
regarding the proposed requirement for full-enclosure with negative 
pressure. After reviewing and considering the comments and other 
information regarding the costs and feasibility of full-enclosure, we 
determined that full-enclosure with negative pressure may not be 
feasible for these facilities and, if feasible, would be much more 
costly than what we had estimated for the 2011 proposal. Therefore we 
evaluated other potential approaches to reduce fugitive process 
emissions based on enhanced local capture and control of the fugitive 
emissions and secondary capture and control, which are described in 
more detail below.
    We also gathered additional emissions data for the process vents. 
Therefore, we have updated and revised our technology review for the 
process vent emissions and fugitive emissions control options. The 
following paragraphs describe the up-dated and revised technology 
review and additional analyses that were performed for today's 
supplemental proposal.
1. Process Vent Emission Limits
    The ferroalloy production facilities have add-on control devices 
such as venturi scrubbers or fabric filters to control emissions of 
metal HAP from the furnace operations. The furnace operations include 
charging, smelting and tapping. Other operations that take place inside 
the furnace buildings include casting and ladle treatment. The vast 
majority of emissions from the charging and smelting processes are 
currently vented to the add-on control devices. However, the percent of 
emissions currently captured and controlled from tapping, ladle 
treatment and casting are considerably lower and varies across 
furnaces. The ferroalloy production facilities also use add-on control 
devices to reduce emissions from the metal oxygen refining (MOR) 
process, local ventilation sources (e.g., tapping fugitive control 
device) and the product crushing operations.
    To evaluate the effectiveness of these emission control 
technologies currently used to reduce emissions and meet the emission 
limits in the 1999 MACT rule, an ICR under section 114 of the Clean Air 
Act was sent to each of the ferroalloy production facilities on April 
28, 2010 and December 21, 2012 to gather source emissions test data and 
other information for the furnaces, the MOR process and the product 
crushing operations. The HAP source test data that were collected from 
the control device outlet for each furnace include: metal HAP (arsenic, 
cadmium, chromium (total and Cr\+6\), lead compounds, manganese, 
mercury and nickel) \41\, HCl, formaldehyde, PAH,

[[Page 60259]]

PCB and chlorodibenzodioxins and chlorodibenzofurans (CDD/CDF). In 
addition, emissions were measured from the furnace control device 
outlet for two non-HAP air pollutants (carbon monoxide and particulate 
matter). The pollutants measured from the MOR and crushing and sizing 
operations in 2010 include particulate matter (PM) and metal HAP 
(arsenic, total chromium, lead compounds, manganese, mercury and 
nickel).\42\ In addition, the facilities provided compliance test 
reports from 2011 and 2012 and additional emissions data they collected 
voluntarily, which included test data for PM, metal HAP (arsenic, 
cadmium, total chromium, lead compounds, manganese, mercury and nickel) 
and organic HAP (PAH, PCB, CDD/CDF) from the furnace control device 
outlets.
---------------------------------------------------------------------------

    \41\ Total phosphorus was also measured for the ICR using EPA 
Method 29; however this method does not distinguish between white 
phosphorus (which is a non-HAP) and red phosphorus (which is a HAP). 
Due to the uncertainty of the percentage of red phosphorus in the 
total phosphorus test results, it was concluded that phosphorus 
would not be incorporated in the emissions used for modeling.
    \42\ Total phosphorus was also measured using Method 29, but was 
not used in the technology review.
---------------------------------------------------------------------------

    The test data collected from the ICR responses, the compliance 
reports and other testing indicate that the PM emissions from the 
furnace process vents (also known as process stacks) are well below the 
level of emissions allowed by the current emission standards in subpart 
XXX. In the 2011 proposal, we proposed lower PM limits to reflect the 
better performance of these sources. We also proposed lower limits for 
the MOR process and the crushing and screening process vents in the 
2011 proposal. We did not receive any additional test data for the MOR 
process or the crushing and screening process since the 2011 proposal 
and have received no other information indicating that changes to the 
limits we proposed in 2011 for these sources are necessary, therefore 
we plan no changes to the proposed emission standards in this 
supplemental proposal for the MOR process and the crushing and 
screening processes.
    However, for the furnace process vents, we did receive additional 
data and based on that data combined with the data we already had, we 
evaluated whether it is appropriate to propose revised emissions limits 
for PM from the furnace process vents. We also re-evaluated the 
proposed emission limits for the local ventilation system based on the 
new test data received. Further discussions of the re-evaluations and 
the proposed revised limits are presented in Section IV below.
    For purposes of addressing new ferroalloy production facilities, we 
considered the feasibility of more stringent emission limits. 
Specifically, we examined what emission level could be met using 
available add-on control devices and the emission concentrations that 
could be achieved by the use of the control devices. The results of 
this analysis and the proposed decisions are described in Section IV 
below.
2. Process Fugitive Control Standards
    We re-evaluated the costs and operational feasibility associated 
with the option of requiring full building enclosure with negative 
pressure at all openings. We also consulted with ventilation experts 
working with hot process fugitives like those found in the ferroalloys 
industry (e.g., electric arc furnace steel mini-mills and secondary 
lead smelters). Furthermore, we received detailed information from each 
of the Ferroalloys facilities that provides an alternative approach to 
achieve significant reductions of process fugitive emissions using 
enhanced local capture, including primary and secondary hoods, which 
would effectively capture most of the fugitive process emissions and 
route these emissions to a PM control device (e.g., baghouse or wet 
scrubber). The plans provided by the facilities are designed to achieve 
a high overall level of control. These plans are available in the 
docket for this action (identified by document numbers: EPA-HQ-OAR-
2010-0895-0106 and EPA-HQ-OAR-2010-0895-0073).
    We also reviewed other options to control process fugitive 
emissions. When we consider the evolution of the EPA rules on process 
fugitives in the metallurgical industry, we observe that the primary 
emphasis on quantifiable emission standards is based on controlling 
stack emissions with a high degree of efficiency. Standards related to 
emissions capture are generally related to parameter monitoring of flow 
rates and damper positions of capture equipment when the stack emission 
test is occurring. There typically has not been an independent 
evaluation of the effectiveness of process fugitive control through 
local ventilation in a quantitative, rigorous manner.
    However, there is a history of addressing fugitive emissions by 
requiring a building opacity limit, including a 20 percent limit in the 
current subpart XXX (although this limit also contains a 60-percent 
short-term excursion and it excludes some key process fugitives events 
such as casting). Subpart FFFFF of Part 63, National Emission Standards 
for Hazardous Air Pollutants for Integrated Iron and Steel 
Manufacturing Facilities, contains various building opacity limits 
ranging from 20 percent for existing sources to 10 percent for new 
sources. Section 60.272a in the Subpart AAa--Standards of Performance 
for Steel Plants: Electric Arc Furnaces and Argon-Oxygen 
Decarburization Vessels Constructed After August 17, 1983 establishes a 
shop building opacity limit of 6 percent, due solely to the operations 
of affected electric arc furnace (EAF)(s) or argon-oxygen 
decarburization vessel (AOD vessel)(s). Building opacity limits in 
these rules serve as an emissions standard for the control of process 
fugitive emissions. Opacity limits can ensure effective capture and 
control of these fugitive emissions if they are established at the 
appropriate levels and have appropriate compliance monitoring 
requirements to ensure the fugitive emissions are minimized 
continuously over time.
    After reviewing and evaluating available information regarding 
approaches to reduce process fugitive emissions, we revised our 
analysis of options to control these fugitive emissions. The results of 
the revised analyses of control options for process fugitive emissions 
are summarized in Section IV and also presented in the Cost Impacts of 
Control Options to Address Fugitive HAP Emissions for the Ferroalloys 
Production NESHAP Supplemental Proposal document and the Revised 
Technology Review for the Ferroalloys Production Source Category for 
the Supplemental Proposal document (Revised Technology Review 
document), which are available in the docket.

IV. Revised Analytical Results and Proposed Decisions for the 
Ferroalloys Production Source Category

A. What actions are we taking pursuant to CAA sections 112(d)(2) and 
112(d)(3)?

    As described previously, CAA section 112(d) requires the EPA to 
promulgate national technology-based emission standards for hazardous 
air pollutants (NESHAP) for listed source categories, including this 
source category. In the 2011 proposal, we proposed emissions limits for 
mercury, PAHs and HCl, which were previously unregulated HAP, pursuant 
to section 112(d)(2) and 112(d)(3). After proposal, we received a 
substantial amount of additional data for these HAP and re-analyzed the 
proposed limits for these HAP considering the additional data.
    Based on those analyses we determined it is appropriate to propose 
revised limits for these three HAP. Therefore, in today's supplemental 
notice, we are proposing revised emissions limits pursuant to section 
112(d)(2) and 112(d)(3) for mercury, PAHs and HCl. In this section, we 
describe how we developed the revised

[[Page 60260]]

proposed standards for these HAP, including how we calculated MACT 
floor limits, how we account for variability in those floor 
calculations and how we considered beyond the floor (BTF) options. The 
revised MACT analyses for these previously unregulated pollutants 
(i.e., mercury, PAH and HCl) are presented in the following paragraphs. 
For more information on these analyses, see the Revised MACT Floor 
Analysis for the Ferroalloys Production Source Category and the Mercury 
Control Options and Impacts for the Ferroalloys Production Industry 
documents which are available in the docket for this action.
1. How do we develop MACT floor limits?
    As discussed in the 2011 proposal (76 FR 72508), the MACT floor 
limit for existing sources is calculated based on the average 
performance of the best performing units in each category or 
subcategory, and also on a consideration of these units' variability, 
and the MACT floor for new sources is based on the single best 
performing source, with a similar consideration of that source's 
variability. The MACT floor for new sources cannot be less stringent 
than the emissions performance that is achieved in practice by the 
best-controlled similar source. To account for variability in the 
operation and emissions, the stack test data were used to calculate the 
average emissions and the 99 percent upper predictive limit (UPL) to 
derive the MACT floor limits. For more information regarding the 
general use of the UPL and why it is appropriate for calculating MACT 
floors, see the memorandum titled Use of the Upper Prediction Limit for 
Calculating MACT Floors (UPL Memo), which is available in the docket 
for this action. Furthermore, with regard to calculation of MACT Floor 
limits based on limited datasets, we considered additional factors as 
summarized below and described in more details in the memorandum 
titled: Approach for Applying the Upper Prediction Limit to Limited 
Datasets, which is available in the docket for this action.
2. What is our approach for applying the upper prediction limit to 
limited datasets?
    The UPL approach addresses variability of emissions data from the 
best performing source or sources in setting MACT standards. The UPL 
also accounts for uncertainty associated with emission values in a 
dataset, which can be influenced by components such as the number of 
samples available for developing MACT standards and the number of 
samples that will be collected to assess compliance with the emission 
limit. The UPL approach has been used in many environmental science 
applications.43 44 45 46 47 48 As explained in more detail 
in the UPL Memo, the EPA uses the UPL approach to reasonably estimate 
the emissions performance of the best performing source or sources to 
establish MACT floor standards.
---------------------------------------------------------------------------

    \43\ Gibbons, R. D. (1987), Statistical Prediction Intervals for 
the Evaluation of Ground-Water Quality. Groundwater, 25: 455-465 and 
Hart, Barbara F. and Janet Chaseling, Optimizing Landfill Ground 
Water Analytes--New South Wales, Australia, Groundwater Monitoring & 
Remediation, 2003, 23, 2.
    \44\ Wan, Can; Xu, Zhao; Pinson, Pierre; Dong, Zhao Yang; Wong, 
Kit Po. Optimal Prediction Intervals of Wind Power Generation. 2014. 
IEEE Transactions on Power Systems, ISSN 0885-8950, 29(3): pp. 1166-
1174.
    \45\ Khosravi, Abbas; Mazloumi, Ehsan; Nahavandi, Saeid; 
Creighton, Doug; van Lint, J. W. C. Prediction Intervals to Account 
for Uncertainties in Travel Time Prediction. 2011. IEEE Transactions 
on Intelligent Transportation Systems, ISSN 1524-9050, 12(2):537-
547.
    \46\ Ashkan Zarnani; Petr Musilek; Jana Heckenbergerova. 2014. 
Clustering numerical weather forecasts to obtain statistical 
prediction intervals. Meteorological Applications, ISSN 1350-4827. 
21(3): 605.
    \47\ Rayer, Stefan; Smith, Stanley K; Tayman, Jeff. 2009. 
Empirical Prediction Intervals for County Population Forecasts. 
Population Research and Policy Review, 28(6): 773-793.
    \48\ Nicholas A Som; Nicolas P Zegre; Lisa M Ganio; Arne E 
Skaugset. 2012. Corrected prediction intervals for change detection 
in paired watershed studies. Hydrological Sciences Journal, ISSN 
0262-6667, 57(1): 134-143
---------------------------------------------------------------------------

    With regard to the derivation of MACT limits using limited 
datasets, in a recent D.C. Circuit Court of Appeals decision in 
National Association of Clean Water Agencies v. EPA (NACWA), 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 (i.e., Limited Dataset 
Memo), which is available in the docket for this action. 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 
supplemental proposal, which are described in the following sections of 
today's notice and in the Limited Dataset Memo.
3. How did we apply the approach for limited datasets to limited 
datasets in the ferroalloys source category?
    For the ferroalloys source category, we have limited datasets for 
the following pollutants and subcategories: PAHs for existing and new 
furnaces producing ferromanganese (FeMn); PAHs for new furnaces 
producing silicon manganese (SiMn); mercury for new furnaces producing 
SiMn; mercury for existing and new furnaces producing FeMn; and HCl for 
new furnaces producing FeMn or SiMn. Therefore, we evaluated these 
specific datasets to determine whether it is appropriate to make any 
modifications to the approach used to calculate MACT floors for each of 
these datasets.
    For each dataset, we performed the steps outlined in the Limited 
Dataset Memo, including: Ensuring that we selected the data 
distribution that best represents each dataset; ensuring that the 
correct equation for the distribution was then applied to the data; and 
comparing individual components of each small dataset to determine if 
the standards based on small datasets reasonably represent the 
performance of the units included in the dataset. The results of each 
analysis are described and presented below in the applicable sections 
for each of the three HAP (i.e., mercury, PAHs and HCl). We seek 
comments regarding the specific application of the limited dataset 
approach used to derive the proposed emissions limits for Hg, PAHs and 
HCl described in the sections below.
4. How did we develop proposed limits for mercury emissions?
a. Background on Mercury
    As described above, we obtained significant additional data on 
mercury emissions from the two ferroalloys production facilities since 
the 2011 proposal. In particular, we obtained data from each furnace 
and for each product type (ferromanganese and silicomanganese). While 
the mercury test data from the 2010 ICR were collected using EPA Method 
29 and the mercury test data from the 2012 ICR and other submitted test 
reports were collected using EPA Method 30B, the mercury test results 
from the two test methods were considered to be comparable and were 
used in the MACT Floor analysis. All of the test reports provided 
analytical results for mercury that were above the detection limit.
    The raw materials used to produce ferroalloys contain various 
amounts of mercury, which is emitted during the smelting process. These 
mercury emissions are derived primarily from

[[Page 60261]]

the manganese ore although there may be trace amounts in the coke or 
coal used in the smelting process. Some of the mercury that is in 
oxidized form is captured on the particulate matter (PM) and then 
collected in the particle control device (e.g., fabric filter or wet 
scrubber). In contrast, most of the gaseous elemental mercury is not 
captured by these particulate control devices and is largely emitted to 
the atmosphere. Based on the available emissions test data, we estimate 
Eramet (which, as noted above, produces FeMn and SiMn) emits about 342 
pounds per year of mercury from their furnaces and that Felman, which 
produces only SiMn, emits about 35 lb/yr of mercury from their 
furnaces. Pursuant to CAA section 112(d)(2) and 112(d)(3), we are 
proposing to revise the 1999 NESHAP to include emission limits for 
mercury.
b. Calculation of MACT Floor Limits for Mercury
    With regard to determining appropriate MACT limits for mercury, 
importantly, the new test data confirm that ferromanganese (FeMn) 
production has substantially higher mercury emissions compared to 
silicomanganese (SiMn) production and that emissions are considerably 
higher at Eramet as compared to Felman. This finding is based on an 
analysis of the product-specific data sets. Furthermore, we evaluated 
differences in the processes and input materials to try to determine 
the reasons for the significant difference in mercury emissions. Based 
on this evaluation, we have determined the input material recipes for 
producing the different products are quite different. In the case of 
FeMn production, much more of the Mn ore and high carbon coke are used 
to reduce the MnO2 in the ore to Mn to produce FeMn. We 
conclude the difference in emissions of mercury is due to the 
significant differences in the input materials and recipe for FeMn as 
compared to SiMn production.
    Because of the significant differences in the input material and 
the mercury emissions between FeMn and SiMn, we determined that 
subcategories should be created for ferromanganese and silicomanganese 
production, with separate MACT limits for mercury proposed for each 
ferroalloys product (FeMn and SiMn).
    The MACT floor dataset for mercury from existing and new furnaces 
producing FeMn includes 6 test runs from a single furnace. As described 
above, this dataset (for the calculation of MACT limits for mercury 
from furnaces producing FeMn) was considered limited and therefore we 
followed the steps described in the Limited Dataset Memo to determine 
the appropriate MACT floor limits for mercury for furnaces producing 
FeMn. We first determined that the dataset is best represented by a 
normal distribution and ensured that we used the correct equation for 
the distribution. Because the floor for both existing and new furnaces 
is based on the performance of a single unit, our evaluation of the 
data was limited to ensuring that the emission limit is a reasonable 
estimate of the performance of the unit based on our knowledge about 
the process and controls. Accordingly, we compared the calculated 
emission limit to the highest measured value and the average short-term 
emissions from the unit, and found that the calculated emission limit 
is about 2.5 times the short-term average from the unit, which is 
within the range that we see when we evaluate larger data sets using 
our MACT floor calculation procedures. The fairly wide range in mercury 
emissions shown by the available data for this best performing unit 
indicate that variability is significant, and we determined that the 
emission limit is representative of the actual performance of the unit 
upon which the limit is based, considering variability. Therefore, we 
determined that no changes to our standard floor calculation procedure 
were warranted for this pollutant and subcategory, and we are proposing 
that the MACT floor is 170 [micro]g/dscm for Hg from existing furnaces 
producing FeMn. We also note that while we calculated the same MACT 
floor value for new sources, we are proposing a beyond-the-floor 
standard for new sources, which is discussed later in this section of 
this preamble.
    The MACT floor dataset for mercury from new furnaces producing SiMn 
includes 3 test runs from a single furnace (furnace 7 at 
Felman) that we identified as the best performing unit based on average 
emissions. After determining that the dataset is best represented by a 
normal distribution and ensuring that we used the correct equation for 
the distribution, we evaluated the variance of this unit (furnace 
7 at Felman). Our analysis showed that this unit, identified 
as the best unit based on average emissions, also had the lowest 
variance, indicating consistent performance. Therefore, we determined 
that the emission limit reasonably accounts for variability and that no 
changes to the standard floor calculation procedure were warranted for 
this pollutant and subcategory, and we are proposing that the MACT 
floor is 4.0 [mu]g/dscm for Hg from new furnaces producing SiMn.
    With regard to mercury emissions from existing furnaces producing 
SiMn, we have 12 test runs in our dataset. This data set was not 
determined to be a limited data set. Using the 99 percent UPL method 
described above, we calculated the MACT floor limit (or 99 percent UPL) 
for exhaust mercury concentrations from existing furnaces producing 
SiMn to be 12 [mu]g/dscm.
    The MACT floor limits for mercury for existing furnaces are higher 
than the actual emissions measured during the ICR performance tests at 
each plant due to an allowance for variability reflected in the UPL. We 
anticipate that both of the existing sources would be able to meet 
these product-specific MACT Floor limits for existing sources without 
installing additional controls. Therefore, the costs and reductions for 
the MACT floor option were estimated to be zero because we conclude 
that the facilities would be able to meet the mercury limits with their 
current furnace controls.
    The next step in establishing MACT standards is the BTF analysis. 
In this step, we investigate other mechanisms for further reducing HAP 
emissions that are more stringent than the MACT floor level of control 
in order to ``require the maximum degree of reduction in emissions'' of 
HAP. In setting such standards, section 112(d)(2) requires the Agency 
to consider the cost of achieving the additional emission reductions, 
any non-air quality health and environmental impacts and energy 
requirements. Historically, these factors have included factors such as 
solid waste impacts of a control, effects of emissions on bodies of 
water, as well as the energy impacts.
c. Beyond the Floor Analysis for Mercury for Existing Furnaces
    As described below, we considered BTF control options to further 
reduce emissions of mercury. The BTF mercury control options were 
developed assuming sub-categorization of furnace melting operations 
into ferromanganese production operations and silicomanganese 
production operations and installing activated carbon injection (ACI) 
technology with brominated carbon to control mercury emissions.
    The BTF mercury limits would be based on the estimated mercury 
emission reduction that can be achieved through the use of ACI and 
brominated carbon. The bromine in the activated carbon can oxidize 
elemental mercury (Hg\0\) to oxidized mercury (Hg\+2\). The oxidized 
mercury is then suitable for capture on the activated carbon sorbent

[[Page 60262]]

or further reacts with the bromine to produce mercuric bromide 
(HgBr2). Both the oxidized mercury and the mercuric bromide 
can be removed using a PM control device. It is generally accepted that 
the installation of ACI in conjunction with a fabric filter achieves at 
least 90 percent reduction of mercury.\49\
---------------------------------------------------------------------------

    \49\ Sargent & Lundy, IPM Model--Revisions to Cost and 
Performance for APC Technologies, Mercury Control Cost Development, 
Final, March 2013.
---------------------------------------------------------------------------

    All three furnaces at Felman and one of the two furnaces at Eramet 
(Furnace 1) are equipped with a fabric filter system to reduce 
PM. The other furnace at Eramet (Furnace 12) controls PM using 
a wet venturi scrubber. Limited data are available for mercury 
reduction using ACI with a venturi scrubber system, as described in the 
mercury control options memorandum.\50\ However, we identified one 
study conducted by the Minnesota Taconite Mercury Control Advisory 
Committee that evaluated mercury reductions from particulate scrubber 
systems and ACI.\51\ In 2011, a field trial was conducted at Hibbing 
Taconite to demonstrate the effectiveness of brominated ACI in 
controlling mercury emissions from a taconite facility. The trial of 
the brominated ACI system was conducted in September and October 2011 
and it was determined that 75 percent Hg removal could be achieved with 
a brominated ACI rate of about 3 lb/MMacf (126 lb/hr) for the taconite 
iron ore processing sources. This 75 percent mercury reduction was 
demonstrated during a two-week continuous injection run in this study. 
The project also noted that better mercury removal results could be 
achieved with improved sorbent distribution. Therefore, although the 
ferroalloys production furnaces are different than the taconite 
production sources, we assume that the retrofit of ACI on the furnace 
at Eramet controlled by a wet scrubber would achieve 50 percent 
additional mercury reduction beyond the level of control that the 
scrubber is currently achieving. Because of the lower potential mercury 
reductions expected for brominated carbon ACI and a venturi scrubber 
(compared to the reductions that would be achieved with use of ACI with 
fabric filters), we determined that a reduction of 50 percent should be 
used in establishing the BTF mercury emissions limit to ensure that the 
limit could be achieved with brominated ACI on both furnaces at all 
times during FeMn production. Therefore, the BTF limit for FeMn 
production for existing sources would be 82 [mu]g/dscm.
---------------------------------------------------------------------------

    \50\ Memorandum from Bradley Nelson, EC/R to Phil Mulrine, EPA 
OAQPS/SPPD/MICG, Mercury Control Options and Impacts for the 
Ferroalloys Production Industry, March 16, 2014.
    \51\ Michael E Berndt, Minnesota Department of Natural 
Resources, Division of Lands and Minerals, Minnesota Taconite 
Mercury Control Advisory Committee: Summary of Phase One Research 
Results (2010-2012), November 29, 2012. http://files.dnr.state.mn.us/lands_minerals/reclamation/berndt_2012_final.pdf.
---------------------------------------------------------------------------

    We estimated the capital costs, annualized costs, emissions 
reductions and cost effectiveness for the BTF limits for FeMn and SiMn 
production sources. The details regarding how these limits were derived 
and the estimated costs and expected reductions of mercury emissions by 
installing ACI controls, are provided in the Mercury Control Options 
and Impacts for the Ferroalloys Production Industry document which is 
available in the docket.
    Regarding the BTF control option for existing sources that produce 
ferromanganese, we estimated the costs and reductions based on the 
installation of ACI on Furnaces 1 and 12 at Eramet with operation only 
during the production of ferromanganese and a polishing baghouse on 
Furnace 1. Other costs include labor, materials and waste disposal. The 
emissions and annual cost for this BTF control option are based on the 
assumption that both furnaces at Eramet produce ferromanganese 50 
percent of the time annually and produce SiMn the other 50 percent of 
the year. We based this reasonable assumption on available information 
regarding production patterns for the 2 products at Eramet. The 
estimated mercury reduction that would be achieved at Furnace 1 at 
Eramet (which is currently controlled with a baghouse) is assumed to be 
90 percent based on the installation of ACI and a new polishing 
baghouse. Regarding Furnace 12 at Eramet (which is currently controlled 
with a wet venturi scrubber), the mercury reductions that would be 
achieved with brominated ACI are assumed to be 50 percent. For the BTF 
control option for existing sources that produce ferromanganese, we 
estimate the capital costs would be about $30 million, annualized costs 
of about $3.3 million and would achieve about 191 pounds per year of 
reductions in mercury emissions, which results in estimated cost-
effectiveness of about $17,600 per pound. All the costs and reductions 
would be at Eramet since Eramet is the only facility in the U.S. that 
produces FeMn.
    As stated earlier the cost-effectiveness is estimated to be 
$17,600/lb. However, it is important to note that cost-effectiveness is 
but one factor we consider in assessing the cost of the emission 
reduction at issue here. See NRDC v. EPA, 749 F.3d 1055, 1060 (D.C. 
Cir. April 18, 2014) (``Section 112 does not command EPA to use a 
particular form of cost analysis.''). We also consider other factors in 
assessing the cost of the emission reduction as part of our beyond-the-
floor analysis, including, but not limited to, total capital costs, 
annual costs and costs compared to total revenues (e.g., costs to 
revenue ratios).
    As mentioned above, we estimate the capital costs would be about 
$30 million, annualized costs of about $3.3 million and that all these 
costs would be for Eramet, which is the only facility in the United 
States that produces FeMn. Furthermore, we estimate the annual costs 
for BTF controls for mercury at Eramet (in addition to the costs for 
controls for fugitive HAP emissions required as part of the risk 
analysis explained later in this preamble) would be about 3 percent of 
revenues, which we believe is potentially significant given the facts 
at issue here. In addition, it is our understanding that for the past 
few years the plant has not made any profits. More details regarding 
the potential economic impacts of the BTF option are provided in the 
Economic Impact Analysis (EIA) for the Manganese Ferroalloys RTR 
Supplemental Proposal document which is available in the docket for 
this action.
    We also evaluated an approach that could reduce the compliance 
costs of the BTF option. We considered the possibility that Eramet 
could potentially decide to produce FeMn in only one furnace and if so, 
would only need to install ACI for 1 furnace. If so, the costs for 
Eramet to comply with the BTF option could be significantly lower. This 
approach would reduce production flexibility, which could pose 
significant production issues for the company, but would allow Eramet 
to avoid some of the emissions control costs under the BTF option. 
However, we realize there would likely be production issues and other 
issues, with this approach. Furthermore, we believe it would be 
inappropriate for the rule to essentially restrict production 
flexibility. Therefore for our cost impacts analysis of the BTF option 
we have assumed brominated ACI would be needed for both furnaces.
    Based on the available economic information, assuming market 
conditions remain approximately the same, we believe Eramet Marietta 
would not be able to sustain the costs of BTF mercury controls (in 
addition to the fugitive control costs required as part of the risk 
analysis explained later in this

[[Page 60263]]

preamble, in Section IV.C.).\52\ This would likely result in 
substantial economic impacts in the short-term and potential closure of 
the facility in the longer-term. Since Eramet Marietta is the only 
facility in the United States which produces FeMn, closure of this 
facility would eliminate 100 percent of the United States production of 
FeMn, which is an important product for the steel industry. After 
considering all the factors described above, we are not proposing BTF 
limits for mercury for FeMn production.
---------------------------------------------------------------------------

    \52\ As noted in our risk analysis explained later in this 
preamble, proposal of the MACT floor standard for mercury (along 
with the controls for fugitive manganese emissions, which are 
explained later in this preamble) provide an ample margin of safety 
to protect public health.
---------------------------------------------------------------------------

    We also evaluated possible BTF controls for existing SiMn 
production sources, which have much lower mercury emissions as compared 
to FeMn production. We estimated that the BTF option for SiMn would 
achieve an additional 60 pounds/year reductions and that the cost-
effectiveness would be about $109,000 per pound of mercury reduced for 
SiMn production, which we conclude is not cost-effective as a BTF 
option. Furthermore, based on our economic analyses, we believe that 
the Felman facility could be at potential risk of closure under this 
option, especially given that these costs would be in addition to the 
costs for controlling fugitive HAP metals emissions (such as Mn, As, Ni 
and Cd). Therefore, we are not proposing BTF limits for mercury for 
SiMn production.
d. Beyond the Floor Analysis for New and Reconstructed Furnaces
    Regarding BTF controls for new or major reconstructed furnaces, we 
believe such sources would be constructed to include a baghouse as the 
primary PM control device (in order to comply with the proposed lower 
new source limits for PM) and then they could add ACI after the 
baghouse for mercury control along with a polishing baghouse and would 
achieve at least 90 percent reduction. Therefore, the BTF limit for new 
FeMn production sources is calculated to be 17 [mu]g/dscm. Regarding 
SiMn, the BTF limit for new sources producing SiMn would be 1.2 [mu]g/
dscm.
    The estimated costs for beyond the floor controls for mercury for 
new and reconstructed sources are based on the costs of installing and 
operating brominated ACI and a polishing baghouse. Based on this, we 
estimate that the cost effectiveness of BTF controls for a new and 
major reconstructed FeMn production source would be about $12,000/lb. 
Therefore, we conclude that BTF controls would be cost-effective and 
feasible for any new or major reconstructed furnace that produces FeMn. 
Therefore we are proposing a limit of 17 [mu]g/dscm for new or major 
reconstructed furnaces that produce FeMn.
    However, for a new SiMn production source, the cost effectiveness 
would be at least $51,000/lb. Therefore, we believe BTF controls for 
new SiMn production sources would not be cost-effective. Furthermore, 
for SiMn production, as described above, the new source MACT floor 
limit is already low (i.e., 4.0 [mu]g/dscm). Therefore we are proposing 
an emissions limit of 4.0 [mu]g/dscm for new or major reconstructed 
SiMn production furnaces based on the new source MACT Floor.
e. Proposed Limits for Existing, New and Reconstructed Sources
    Based on all our analyses described above, we are proposing mercury 
limits based on the MACT Floor (UPL) for each product type 
(ferromanganese, silicomanganese) for existing furnaces; BTF limits for 
mercury for new and reconstructed FeMn production furnaces; and mercury 
limits for new and reconstructed SiMn production furnaces based on the 
MACT Floor. These limits are summarized in Table 4.

     Table 4--Summary of the Proposed Mercury Control Emissions Limits ([mu]g/dscm) From the Furnace Melting
                                                    Processes
----------------------------------------------------------------------------------------------------------------
                                                          FeMn production                       SiMn production
                                       FeMn production        (new and       SiMn production        (new and
      Proposed mercury controls           (existing        reconstructed        (existing        reconstructed
                                           sources)           sources)           sources)           sources)
----------------------------------------------------------------------------------------------------------------
MACT Floor limits for FeMn and SiMn                 170                 17                 12                4.0
 existing sources; BTF limit for new
 and reconstructed FeMn sources; and
 MACT floor limit for new and
 reconstructed SiMn sources.........
----------------------------------------------------------------------------------------------------------------

5. How did we develop proposed limits for Polycyclic Aromatic 
Hydrocarbons (PAHs)?
    As described above, we obtained additional data on PAH emissions 
from the two ferroalloys production facilities since the 2011 proposal. 
In particular, we obtained data from each furnace and for each product 
type (FeMn and SiMn). We used the resulting dataset to re-evaluate the 
MACT floor limits and BTF options. For more information on this 
analysis, see Revised MACT Floor Analysis for the Ferroalloys 
Production Source Category, which is available in the docket.
    As in the case of the mercury analysis, our results show that there 
is a significant difference in PAH emissions during FeMn production as 
compared to SiMn production. Furthermore, similar to mercury, we 
conclude that this difference is due to significant differences in the 
recipe and input materials for FeMn compared to SiMn production.
    Therefore, we determined that it would be appropriate to have two 
subcategories for PAH emissions and establish separate MACT limits for 
each of these two subcategories.
    The MACT floor dataset for PAHs from existing furnaces producing 
FeMn includes 6 test runs from 2 furnaces. As described above, this 
dataset (for the calculation of the MACT Floor limit for PAHs for FeMn 
production furnaces) was considered a limited dataset and therefore we 
followed the steps described in the Limited Dataset Memo to determine 
the appropriate MACT Floor limit for PAHs for these sources. This 
subcategory includes only two units, and the CAA specifies that the 
existing source MACT floor for subcategories with fewer than 30 sources 
shall not be less stringent than ``the average emission limitation 
achieved by the best performing 5 sources.'' However, since there are 
only 2 units in the subcategory and we have data for both units, the 
data from both units serve as the basis for the MACT floor. After 
determining that the dataset is best represented by a normal 
distribution and ensuring that we used

[[Page 60264]]

the correct equation for the distribution, we considered the selection 
of a lower confidence level for determining the emission limit by 
evaluating whether the calculated limit reasonably represents the 
performance of the units upon which it is based. In this case, where 
two units make up the pool of best performers, the calculated emission 
limit is about twice the short-term average emissions from the best 
performing sources, indicating that the emission limit is not 
unreasonable compared to the actual performance of the units upon which 
the limit is based and is within the range that we see when we evaluate 
larger datasets using our MACT floor calculation procedures. Therefore, 
we determined that no changes to our standard floor calculation 
procedure are warranted for this pollutant and subcategory, and we are 
proposing that the MACT floor is 1,400 [mu]g/dscm for PAHs from 
existing furnaces producing FeMn.
    The MACT floor dataset for PAHs from new furnaces producing FeMn 
includes 3 test runs from a single furnace (furnace 12 at 
Eramet) that we identified as the best performing unit based on average 
emissions performance. After determining that the dataset is best 
represented by a normal distribution and ensuring that we used the 
correct equation for the distribution, we evaluated the variance of the 
best performing unit. Our analysis showed that this unit, which was 
identified as the best unit based on average emissions, also had the 
lowest variance. Therefore, we determined that the emission limit would 
reasonably account for variability and that no changes to the standard 
floor calculation procedure were warranted for this pollutant and 
subcategory, and we are proposing that the MACT floor is 880 [mu]g/dscm 
for PAHs from new furnaces producing FeMn.
    The MACT floor dataset for PAHs initially identified for new 
furnaces producing SiMn includes 6 test runs from a single furnace 
(furnace 2 at Felman) that we identified as the best 
performing unit based on average emissions. After determining that the 
dataset is best represented by a normal distribution and ensuring that 
we used the correct equation for the distribution, we evaluated the 
variance of this unit (furnace 2 at Felman) and concluded that 
further consideration of the variance was warranted. In particular, we 
noted that the variance of the dataset for this unit was almost twice 
as large as the variance of the dataset for the pool of best performing 
units that was used to calculate the existing source MACT floor. The 
high degree of variance in the dataset for the unit with the lowest 
average prompted us to question whether this unit was, in fact, the 
best performing unit and to evaluate the dataset for the unit with the 
next lowest average (furnace 7 at Felman). The dataset for 
furnace 7 includes 3 test runs, the furnaces are controlled 
with the same type of add-on control technology, and the average 
emissions from furnace 2 are only about 22 percent lower than 
the average emissions from furnace 7. While we find the 
average performance of these 2 units to be similar, the unit with the 
higher average has a variance more than 2 orders of magnitude lower 
than that of the unit with the lower average, thus indicating that the 
unit with the higher average has a far more consistent level of 
performance. The combination of components from the unit with the 
higher average (furnace 7) yields an emissions limit that is 
lower than that calculated from the dataset of the unit (furnace 
2) with the lowest average (71.7 versus 132.8 [mu]g/dscm). For 
these reasons, we determined that the unit with the lowest average 
(furnace 2) is not the best performing source for this 
pollutant and we are instead selecting furnace 7 as the best 
performing source. After selecting the source upon which the new source 
limit would be based, we next considered whether the selection of a 
different confidence level would be appropriate. In this case, we 
determined that a lower confidence level was not warranted given the 
small amount of variability in the data for the unit that we identified 
as the best performer. Based on the factors outlined above, we are 
proposing that the MACT floor is 72 [mu]g/dscm for PAHs from new 
furnaces producing SiMn.
    With regard to PAH emissions from existing furnaces producing SiMn, 
we have 18 test runs in our dataset. This dataset was not determined to 
be a limited data set. The UPL results for this dataset using a 99 
percent confidence level was determined to be 120 [mu]g/dscm for SiMn 
production and was determined to be the MACT floor limit for PAHs for 
existing furnaces producing SiMn.
    Based on the data we received prior to summer 2014, we estimate 
that neither source would need to install additional controls to meet 
the MACT Floor emission limits described above. However, as mentioned 
in Section II.D of today's notice, we received additional PAH data in 
August 2014. We have not yet completed our review and technical 
analyses of those new data, and have not yet incorporated these new 
data into our analyses. Nevertheless, we are seeking comments regarding 
the new PAH data and how these data could affect our analyses.
    The current PM controls on both facilities capture some of PAH 
emissions. Nevertheless, we also considered BTF options for control of 
PAH emissions based on the additional reductions that could be achieved 
via control with ACI. Based on information from carbon vendors, an 
activated carbon system that is designed to achieve up to 90 percent 
reduction in mercury emissions should also achieve significant 
reductions in PAH with no additional costs. However, significant 
uncertainties remain regarding the percent of reductions in PAHs that 
would be achieved with ACI. One study \53\ found that ACI can achieve 
74-91 percent reduction in PAH emissions depending on the concentration 
of activated carbon in the flue gas. Based on this information, we 
assume that ACI probably can achieve 75 percent reduction in PAH 
emissions from the furnace. Therefore, for our analysis of BTF options, 
we assumed an ACI system can achieve 75 percent reduction of PAH 
emissions from the furnace exhaust. Based on this assumption, possible 
BTF limits for PAHs would be 340 [mu]g/dscm for FeMn production 
furnaces and 28 [mu]g/dscm for SiMn production furnaces. The estimated 
capital and annualized costs to achieve these BTF PAH limits are the 
same costs as those shown for mercury in the mercury control options 
memorandum. For FeMn production, the capital cost was calculated to be 
$30.2 million and the annual cost was calculated to be $3.4 million and 
would only apply to the furnaces at Eramet and the estimated PAH 
reductions would be 2.35 tons per year, which results in cost-
effectiveness of $1.4 million per ton of PAH. The capital cost for a 
beyond the floor PAH option for SiMn and FeMn production was calculated 
to be $41.7 million with an annual cost of $6.9 million and the 
estimated PAH reductions would be 4.0 tons per year, which results in 
cost-effectiveness of $1.7 million per ton, which we conclude is not 
cost-effective for PAHs. Given the uncertainties regarding the percent 
of PAH reductions that can be achieved with ACI and since the cost-
effectiveness is relatively high for this HAP, we are not proposing BTF 
limits for PAHs. Instead, we have determined that it is appropriate to 
propose PAH limits based on the MACT Floor level of control, therefore 
we are proposing a MACT limit of 1,400 [mu]g/

[[Page 60265]]

dscm for PAHs for existing FeMn production furnaces and 880 [mu]g/dscm 
for PAHs for new and reconstructed FeMn production furnaces and we are 
proposing a MACT floor limit of 120 [mu]g/dscm for PAHs for existing 
SiMn production furnaces and 72 [mu]g/dscm for PAHs for new and 
reconstructed SiMn production furnaces.
---------------------------------------------------------------------------

    \53\ Hong-Cang Zhou, Zhao-Ping Zhong, Bao-Sheng Jin, Ya-Ji Huang 
and Rui Xiao, Experimental study on the removal of PAHs using in-
duct activated carbon injection, Chemosphere, November 17, 2004.

           Table 5--Proposed Emissions Limits ([mu]g/dscm) for PAHs From the Furnace Melting Processes
----------------------------------------------------------------------------------------------------------------
                                                                       FeMn                            SiMn
                                                       FeMn         production         SiMn         production
                                                    production       (new and       production       (new and
                                                     (existing     reconstructed     (existing     reconstructed
                                                     sources)        sources)        sources)        sources)
----------------------------------------------------------------------------------------------------------------
Proposed Emissions Limits for PAHs..............            1400             880             120              72
----------------------------------------------------------------------------------------------------------------

6. How did we develop limits for hydrochloric acid (HCl)?
    Like mercury and PAH, we obtained additional HCl test data since 
proposal. However, more than half the test results (20 of the 36 test 
runs) were below the detection limit. This situation required the use 
of additional statistical analysis, as described in the Revised MACT 
Floor Analysis for the Ferroalloys Production Source Category, which is 
available in the docket. We determined the data set for HCl from 
furnace outlets has a non-normal distribution. The non-normal 
distribution of the data is a result of the mix of analytical results 
reported above and below the detection limit and is not due to the type 
of product being produced (FeMn or SiMn) in the furnace. Therefore, for 
HCL we are not establishing subcategories based on product. An equation 
for log-normally distributed data was used to determine the UPL of the 
HCl dataset for both FeMn and SiMn production combined. The UPL for the 
log-normal dataset was calculated to be 1,100 [mu]g/dscm. Because more 
than half of the dataset were reported below the detection limit, using 
EPA procedures, three times the representative method detection level 
(RDL) for HCl (180 [mu]g/dscm), was compared to the calculated UPL. The 
calculated UPL was higher and, thus, was selected as the MACT floor 
limit for existing furnaces. At this level, we expect neither source 
would need to install additional controls to meet the MACT floor 
emission limits.
    The MACT floor dataset for HCl from new furnaces producing FeMn or 
SiMn includes 6 test runs from a single furnace (furnace 5 at 
Felman) that we identified as the best performing unit based on average 
emissions. As described above, this dataset (for the calculation of the 
new source limit for HCL) was considered a limited dataset and 
therefore we followed the steps described in the Limited Dataset Memo 
to determine the appropriate MACT Floor limit for HCl for new furnaces. 
After determining that the dataset is best represented by a non-normal 
distribution and ensuring that we used the correct equation for the 
distribution, we evaluated the variance of this best performing unit. 
Our analysis showed that this unit, identified as the best unit based 
on average emission, also had the lowest variance, indicating 
consistent performance. Therefore, we determined that the emission 
limit reasonably accounts for variability and that no changes to the 
standard floor calculation procedure were warranted for this pollutant 
and subcategory. We also note that for this standard, the calculated 
new source floor level was below the level that can be accurately 
measured (the level that we refer to as ``3 times the representative 
detection level'' or 3xRDL). Therefore, we are proposing a new source 
MACT emission limit of 180 ppm for HCl, which is the 3xRDL value for 
HCl.
    No facilities in the source category use add-on control devices or 
work practices to limit emissions of HCl beyond what is normally 
achieved as co-control of the emissions with particulate matter control 
device. Also, as explained above, there are a significant number of 
non-detects for HCl. Thus, emissions are already low. Nevertheless, we 
evaluated possible beyond the floor options to further reduce HCl to 
ensure our analyses were complete. The BTF analyses are described in 
the Revised MACT Floor Analysis for the Ferroalloys Production Source 
Category document which is available in the docket. We did not identify 
any appropriate BTF options for HCl.
    Given the low emissions of HCl and the results of our analyses, we 
are not proposing beyond the floor limits for HCl. Therefore, in this 
supplemental proposal, we are proposing emission limits for HCl of 
1,100 [mu]g/dscm for existing furnaces and 180 [mu]g/dscm for new or 
reconstructed furnaces, which are at the level of the MACT floors.

   Table 6--Proposed Emissions Limits ([micro]g/dscm) for HCl From the
                        Furnace Melting Processes
------------------------------------------------------------------------
                                                FeMn and   FeMn and SiMn
                                                  SiMn       production
                                               production     (new and
                                                (existing  reconstructed
                                                sources)      sources)
------------------------------------------------------------------------
Proposed Emissions Limits for HCl............       1100           180
------------------------------------------------------------------------

B. What are the results of the risk assessment and analyses?

1. Inhalation Risk Assessment Results
    Table 7 of this preamble provides an overall summary of the results 
of the inhalation risk assessment.

               Table 7--Ferroalloys Production Source Category Inhalation Risk Assessment Results
----------------------------------------------------------------------------------------------------------------
                                                              Estimated
                                     Estimated Population   Annual Cancer      Maximum       Maximum Screening
 Maximum Individual Cancer Risk (-    at Increased Risk       Incidence     Chronic Non-    Acute Non-cancer HQ
         in-1 million) \a\             Levels of Cancer      (cases per     cancer TOSHI            \c\
                                                                year)            \b\
----------------------------------------------------------------------------------------------------------------
Actual Emissions
                                    >= 1-in-1 million:
                                     31,000.
20................................  >= 10-in-1 million:             0.002               4  HQREL = 1 (arsenic
                                     400.                                                   compounds,
                                                                                            hydrofluoric acid,
                                                                                            formaldehyde)

[[Page 60266]]

 
                                    >= 100-in-1 million:
                                     0.
Allowable Emissions \d\
                                    >= 1-in-1 million:
                                     94,000.
100...............................  >= 10-in-1 million:             0.005              40  --
                                     2,500.
                                    >= 100-in-1 million:
                                     0.
----------------------------------------------------------------------------------------------------------------
\a\ Estimated maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
\b\ Maximum TOSHI. The target organ with the highest TOSHI for the Ferroalloys Production source category for
  both actual and allowable emissions is the neurological system. The estimated population at increased levels
  of noncancer hazard is 1,500 based on actual emissions and 11,000 based on allowable emissions.
\c\ See Section III.A.3 of this notice for explanation of acute dose-response values. Acute assessments are not
  performed on allowable emissions.
\d\ The development of allowable emission estimates can be found in the memorandum titled Revised Development of
  the RTR Emissions Dataset for the Ferroalloys Production Source Category for the 2014 Supplemental Proposal,
  which is available in the docket.

    The inhalation risk modeling performed to estimate risks based on 
actual and allowable emissions relied primarily on emissions data from 
the ICRs and calculations described in the Emissions Memo. The results 
of the chronic baseline inhalation cancer risk assessment indicate 
that, based on estimates of current actual emissions, the maximum 
individual lifetime cancer risk (MIR) posed by the ferroalloys 
production source category is 20-in-1 million, with chromium compounds, 
PAHs and nickel compounds from tapping fugitives, furnace fugitives and 
a furnace accounting for 70 percent of the MIR. The total estimated 
cancer incidence from ferroalloys production sources based on actual 
emission levels is 0.002 excess cancer cases per year or one case every 
500 years, with emissions of PAH, chromium compounds and cadmium 
compounds contributing 42 percent, 18 percent and 15 percent, 
respectively, to this cancer incidence. In addition, we note that 
approximately 400 people are estimated to have cancer risks greater 
than or equal to 10-in-1 million, and approximately 31,000 people are 
estimated to have risks greater than or equal to 1-in-1 million as a 
result of actual emissions from this source category.
    When considering MACT-allowable emissions, the maximum individual 
lifetime cancer risk is estimated to be up to 100-in-1 million, driven 
by emissions of arsenic compounds and cadmium compounds from the MOR 
process baghouse outlet. The estimated cancer incidence is estimated to 
be 0.005 excess cancer cases per year or one excess case in every 200 
years. Approximately 2,500 people are estimated to have cancer risks 
greater than or equal to 10-in-1 million and approximately 94,000 
people are estimated to have cancer risks greater than or equal to 1-
in-1 million considering allowable emissions from ferroalloys 
facilities.
    The risk results described in this section and shown in Table 7 are 
based on the emissions data received prior to summer 2014. These 
results do not reflect the new PAH, PM or mercury data we received in 
August 2014 (as described in Section II.D. in this notice). We seek 
comment on the new data, which are available in the docket for today's 
action, and how these additional data would impact the risk assessment.
    The maximum modeled chronic non-cancer HI (TOSHI) value for the 
source category based on actual emissions is estimated to be 4, with 
manganese emissions from tapping fugitives accounting for 93 percent of 
the HI. Approximately 1,500 people are estimated to have exposure to HI 
levels greater than 1 as a result of actual emissions from this source 
category. When considering MACT-allowable emissions, the maximum 
chronic non-cancer TOSHI value is estimated to be 40, driven by 
allowable emissions of manganese from the MOR process baghouse outlet. 
Approximately 11,000 people are estimated to have exposure to HI levels 
greater than 1 considering allowable emissions from these ferroalloys 
facilities.
2. Acute Risk Results
    Our screening analysis for worst-case acute impacts based on actual 
emissions indicates the potential for three pollutants--arsenic 
compounds, formaldehyde, and hydrofluoric acid--to have HQ values of 1, 
based on their respective REL value. Both facilities have estimated HQs 
of 1 for these pollutants.
    To better characterize the potential health risks associated with 
estimated worst-case acute exposures to HAP from the source category at 
issue and in response to a key recommendation from the SAB's peer 
review of the EPA's section 112(f) RTR risk assessment methodologies, 
we examine a wider range of available acute health metrics than we do 
for our chronic risk assessments. This is in acknowledgement that there 
are generally more data gaps and inconsistencies in acute reference 
values than there are in chronic reference values. By definition, the 
acute CalEPA REL represents a health-protective level of exposure, with 
no risk anticipated below those levels, even for repeated exposures; 
however, the health risk from higher-level exposures is unknown. 
Therefore, when a CalEPA REL is exceeded and an AEGL-1 or ERPG-1 level 
is available (i.e., levels at which mild effects are anticipated in the 
general public for a single exposure), we have used them as a second 
comparative measure. Historically, comparisons of the estimated maximum 
off-site 1-hour exposure levels have not been typically made to 
occupational levels for the purpose of characterizing public health 
risks in RTR assessments. This is because occupational ceiling values 
are not generally considered protective for the general public since 
they are designed to protect the worker population (presumed healthy 
adults) for short-duration (less than 15-minute) increases in exposure. 
As a result, for most chemicals, the 15-minute occupational ceiling 
values are set at levels higher than a 1-hour AEGL-1, making 
comparisons to them irrelevant unless the AEGL-1 or ERPG-1 levels are 
also exceeded.
    All the HAP in this analysis have worst-case acute HQ values of 1 
or less, indicating that they carry no potential to pose acute 
concerns. In characterizing

[[Page 60267]]

the potential for acute non-cancer impacts of concern, it is important 
to remember the upward bias of these exposure estimates (e.g., worst-
case meteorology coinciding with a person located at the point of 
maximum concentration during the hour) and to consider the results 
along with the conservative estimates used to develop peak hourly 
emissions as described earlier, as well as the screening methodology. 
Refer to the document titled Revised Development of the RTR Emissions 
Dataset for the Ferroalloys Production Source Category for the 2014 
Supplemental Proposal (which is available in the docket for this 
action) for a detailed description of how the hourly emissions were 
developed for this source category.
3. Multipathway Risk Screening Results
    Results of the worst-case Tier I screening analysis indicate that 
PB-HAP emissions (based on estimates of actual emissions) from one or 
both facilities in this source category exceed the screening emission 
rates for cadmium compounds, mercury compounds, dioxins and PAH. For 
the compounds and facilities that did not screen out at Tier I, we 
conducted a Tier II screen. The Tier II screen replaces some of the 
assumptions used in Tier I with site-specific data, including the land 
use around the facilities, the location of fishable lakes and local 
wind direction and speed. The Tier II screen continues to rely on high-
end assumptions about consumption of local fish and locally grown or 
raised foods (adult female angler at 99th percentile consumption for 
fish \54\ and 90th percentile for consumption of locally grown or 
raised foods \55\) and uses an assumption that the same individual 
consumes each of these foods in high end quantities (i.e., that an 
individual has high end ingestion rates for each food). The result of 
this analysis was the development of site-specific emission rate 
screening levels for each PB-HAP. It is important to note that, even 
with the inclusion of some site-specific information in the Tier II 
analysis, the multi-pathway screening analysis is still a very 
conservative, health-protective assessment (e.g., upper-bound 
consumption of local fish, locally grown and/or raised foods) and in 
all likelihood will yield results that serve as an upper-bound multi-
pathway risk associated with a facility.
---------------------------------------------------------------------------

    \54\ Burger, J. 2002. Daily consumption of wild fish and game: 
Exposures of high end recreationists. International Journal of 
Environmental Health Research 12:343-354.
    \55\ U.S. EPA. Exposure Factors Handbook 2011 Edition (Final). 
U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/
052F, 2011.
---------------------------------------------------------------------------

    While the screening analysis is not designed to produce a 
quantitative risk result, the factor by which the emissions exceed the 
screening level serves as a rough gauge of the ``upper-limit'' risks we 
would expect from a facility. Thus, for example, if a facility emitted 
a PB-HAP carcinogen at a level 2 times the screening level, we can say 
with a high degree of confidence that the actual maximum cancer risks 
will be less than 2-in-1 million. Likewise, if a facility emitted a 
noncancer PB-HAP at a level 2 times the screening level, the maximum 
noncancer hazard would represent an HQ less than 2. The high degree of 
confidence comes from the fact that the screens are developed using the 
very conservative (health-protective) assumptions that we describe 
above.
    Based on the Tier II screening analysis, no facility emits cadmium 
compounds above the Tier II screening levels. One facility emits 
mercury compounds above the Tier II screening levels and exceeds that 
level by a factor of 9. Both facilities emit chlorinated dibenzodioxins 
and furans (CDDF) as 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity 
equivalent (TEQ) above the Tier II screening levels and the facility 
with the highest emissions of dioxins exceeds its Tier II screening 
level by a factor of 20. Both facilities emit POM as benzo(a)pyrene TEQ 
above the Tier II screening levels and the facility with the highest 
emissions exceeds its screening level by a factor of 20.
    Polychlorinated biphenyls (PCB) are PB-HAP that do not currently 
have multi-pathway screening values and so are not evaluated for 
potential non-inhalation risks. These HAP however, are not emitted in 
appreciable quantities (estimated to be 0.00026 tpy) from the 
ferroalloys source category and we do not believe they contribute to 
multi-pathway risks for this source category.
    Results of the analysis for lead indicate that based on the 
baseline, actual emissions, the maximum annual off-site ambient lead 
concentration was only 50 percent of the NAAQS for lead and if the 
total annual emissions occurred during a 3-month period, the maximum 3-
month rolling average concentrations would exceed the NAAQS. However, 
as shown later in this preamble, based on emissions estimated for the 
post-control scenario, the maximum annual off-site ambient lead 
concentration was only 3 percent of the NAAQS for lead. If the total 
annual emissions occurred during a 3-month period, the maximum 3-month 
rolling average concentrations would be about 12 percent of the NAAQS 
for lead, indicating that there is no concern for multi-pathway risks 
due to lead emissions.
4. Multipathway Refined Risk Results
    A refined multipathway analysis was conducted for one facility in 
this source category using the TRIM.FaTE model. The facility, Eramet 
Marietta Incorporated, in Marietta, Ohio, was selected based upon its 
close proximity to nearby lakes and farms as well as having the highest 
potential multipathway risks for three of the four PB-HAP based on the 
Tier II analysis. These three PB-HAP were cadmium, mercury and PAHs. 
(Even though neither facility exceeded the Tier II screening levels for 
cadmium, Eramet had the higher value.) Eramet also emits dioxins, but 
the other facility had a higher exceedance of its Tier II screening 
level. The refined analysis was conducted on all four PB-HAP. The 
refined analysis for this facility showed that the Tier II screen for 
each pollutant over-predicted the potential risk when compared to the 
refined analysis results.
    Overall, the refined analysis predicts a potential lifetime cancer 
risk of 10-in-1 million to the maximum most exposed individual due to 
exposure to dioxins and PAHs. The non-cancer HQ is predicted to be 
below 1 for cadmium compounds and 1 for mercury compounds.
    Further details on the refined multipathway analysis can be found 
in Appendix 10 of the Residual Risk Assessment for the Ferroalloys 
Production Source Category in Support of the September 2014 
Supplemental Proposal, which is available in the docket.
5. Environmental Risk Screening Results
    As described in Section III.A, we conducted an environmental risk 
screening assessment for the ferroalloys source category. In the Tier I 
screening analysis for PB-HAP the individual modeled Tier I 
concentrations for one facility in the source category exceeded some 
sediment, fish--avian piscivorus and surface soil benchmarks for PAHs, 
methylmercury and mercuric chloride. Therefore, we conducted a Tier II 
assessment.
    In the Tier II screening analysis for PAHs and methylmercury none 
of the individual modeled concentrations for any facility in the source 
category exceeded any of the ecological benchmarks (either the LOAEL or 
NOAEL). For mercuric chloride, soil benchmarks were exceeded for some 
individual modeled points that collectively accounted for 5 percent of 
the modeled area. However, the

[[Page 60268]]

weighted average modeled concentration for all soil parcels was well 
below the soil benchmarks.
    For HCl, each individual concentration (i.e., each off-site data 
point in the modeling domain) was below the ecological benchmarks for 
all facilities. The average modeled HCl concentration around each 
facility (i.e., the average concentration of all off-site data points 
in the modeling domain) did not exceed any ecological benchmark.
6. Facility-Wide Risk Assessment Results
    For both facilities in this source category, there are no other HAP 
emissions sources present beyond those included in the source category. 
Therefore, we conclude that the facility-wide risk is the same as the 
source category risk and that no separate facility-wide analysis is 
necessary.
7. Demographic Analysis Results
    To examine the potential for any environmental justice (EJ) issues 
that might be associated with the source category, we performed a 
demographic analysis, which is an assessment of risks to individual 
demographic groups, of the population close to the facilities. In this 
analysis, we evaluated the distribution of HAP-related cancer risks and 
non-cancer hazards from the ferroalloys production source category 
across different social, demographic and economic groups within the 
populations living near facilities identified as having the highest 
risks. The methodology and the results of the demographic analyses are 
included in a technical report, Risk and Technology Review--Analysis of 
Socio-Economic Factors for Populations Living Near Ferroalloys 
Facilities, which is available in the docket for this action.
    The results of the demographic analysis are summarized in Table 8 
below. These results, for various demographic groups, are based on the 
estimated risks from actual emissions levels for the population living 
within 50 km of the facilities.

                        Table 8--Ferroalloy Production Demographic Risk Analysis Results
----------------------------------------------------------------------------------------------------------------
                                                                 Population with cancer  Population with chronic
                                                                risk at or above 1-in-1    hazard index above 1
                                              Nationwide             million due to         due to ferroalloys
                                                                 ferroalloys production         production
----------------------------------------------------------------------------------------------------------------
Total Population.....................              312,861,265                   31,283                    1,521
----------------------------------------------------------------------------------------------------------------
                                                 Race by Percent
----------------------------------------------------------------------------------------------------------------
White................................                       72                       96                       99
All Other Races......................                       28                        4                        1
----------------------------------------------------------------------------------------------------------------
                                                 Race by Percent
----------------------------------------------------------------------------------------------------------------
White................................                       72                       96                       99
African American.....................                       13                        1                        0
Native American......................                        1                        0                        0
Other and Multiracial................                       14                        2                        1
----------------------------------------------------------------------------------------------------------------
                                              Ethnicity by Percent
----------------------------------------------------------------------------------------------------------------
Hispanic.............................                       17                        1                        1
Non-Hispanic.........................                       83                       99                       99
----------------------------------------------------------------------------------------------------------------
                                                Income by Percent
----------------------------------------------------------------------------------------------------------------
Below Poverty Level..................                       14                       15                        7
Above Poverty Level..................                       86                       85                       93
----------------------------------------------------------------------------------------------------------------
                                              Education by Percent
----------------------------------------------------------------------------------------------------------------
Over 25 and without High School                             15                       11                       11
 Diploma.............................
Over 25 and with a High School                              85                       89                       89
 Diploma.............................
----------------------------------------------------------------------------------------------------------------

    The results of the ferroalloys production source category 
demographic analysis indicate that emissions from the source category 
expose approximately 31,000 people to a cancer risk at or above 1-in-1 
million and approximately 1,500 people to a chronic non-cancer TOSHI 
greater than 1 (we note that many of those in the first risk group are 
the same as those in the second). The percentages of the at-risk 
population in each demographic group (except for White and non-
Hispanic) are similar to or lower than their respective nationwide 
percentages. Implementation of the provisions included in this proposal 
is expected to significantly reduce the number of people estimated to 
have a cancer risk greater than 1-in-1 million due to HAP emissions 
from these sources from 31,000 people to about 6,600 people. 
Implementation of the provisions included in the proposal also is 
expected to reduce the number of people estimated to have a chronic 
non-cancer TOSHI greater than 1 from 1,500 people to no people with a 
TOSHI greater than 1.

C. What are our proposed decisions regarding risk acceptability, ample 
margin of safety and adverse environmental effects based on our revised 
analyses?

1. Risk Acceptability
    As noted in Section II.A.1 of this preamble, the EPA sets standards 
under CAA section 112(f)(2) using ``a two-step standard-setting 
approach, with an analytical first step to determine an `acceptable 
risk' that considers all health information, including risk estimation 
uncertainty and includes a presumptive limit on maximum individual 
lifetime risk (MIR) of

[[Page 60269]]

approximately 1 in 10 thousand\[\\56\\]\.'' (54 FR 38045, September 14, 
1989).
---------------------------------------------------------------------------

    \56\ 1-in-10 thousand is equivalent to 100-in-1 million. The EPA 
currently describes cancer risks as `n-in-1 million.'
---------------------------------------------------------------------------

    In this proposal, the EPA estimated risks based on both actual and 
allowable emissions from ferroalloy facilities. In determining 
acceptability, we considered risks based on both actual and allowable 
emissions.
a. Estimated Risks From Actual Emissions
    The baseline inhalation cancer risk to the individual most exposed 
to emissions from sources in the ferroalloys source category is 20-in-1 
million based on actual emissions. The estimated incidence of cancer 
due to inhalation exposures is 0.002 excess cancer cases per year, or 1 
case every 500 years. Approximately 31,000 people face an increased 
cancer risk greater than 1-in-1 million due to inhalation exposure to 
actual HAP emissions from this source category and approximately 400 
people face an increased risk greater than 10-in-1 million and up to 
20-in-1 million. The agency estimates that the maximum chronic non-
cancer TOSHI from inhalation exposure is 4, with manganese emissions 
from tapping fugitives accounting for a large portion (93 percent) of 
the HI.
    The Tier II multipathway screening analysis of actual emissions 
indicated the potential for PAH emissions that are about 20 times the 
screening level for cancer, dioxin emissions that are about 20 times 
the screening level for cancer and mercury emissions that are 9 times 
above the screening level for non-cancer.
    As noted above, the Tier II multipathway screen is conservative in 
that it incorporates many health-protective assumptions. For example, 
the EPA chooses inputs from the upper end of the range of possible 
values for the influential parameters used in the Tier II screen and 
assumes that the exposed individual exhibits ingestion behavior that 
would lead to a high total exposure. A Tier II exceedance cannot be 
equated with a risk value or a HQ or HI. Rather, it represents a high-
end estimate of what the risk or hazard may be. For example, an 
exceedance of 2 for a non-carcinogen can be interpreted to mean that we 
have high confidence that the HI would be lower than 2. Similarly, an 
exceedance of 30 for a carcinogen means that we have high confidence 
that the risk is lower than 30-in-1-million. Confidence comes from the 
conservative, or health-protective, assumptions that are used in the 
Tier II screen.
    The refined multipathway analysis that the EPA conducted for one 
specific facility showed that the Tier II screen for each pollutant 
over-predicted the potential risk when compared to the refined analysis 
results. That refined multipathway assessment showed that the Tier II 
screen resulted in estimated risks that are higher than the risks 
estimated by the refined analysis by 3 times for PAH, 2 times for 
dioxins, and 6 times for cadmium. The HQ for mercury went from 9 in 
Tier II to 1.
    The screening assessment of worst-case acute inhalation impacts 
from baseline actual emissions indicates that all pollutants have HQ 
values of 1 or less, based on their respective REL values. Considering 
the conservative, health-protective nature of the approach that is used 
to develop these acute estimates, it is highly unlikely that an 
individual would have an acute exposure above the REL. Specifically, 
the analysis is based on the assumption that worst-case emissions and 
meteorology would coincide with a person being at the exact location of 
maximum impact for a period of time long enough to have an exposure 
level above the conservative REL value. The fact that the facilities in 
this source category are not located in areas that naturally lead to 
people being near the fence line for periods of time indicates that the 
exposure scenario used in the screening assessment would be unlikely to 
occur.
b. Estimated Risks From Allowable Emissions
    The EPA estimates that the baseline inhalation cancer risk to the 
individual most exposed to emissions from sources in the ferroalloys 
source category is up to 100-in-1 million based on allowable emissions, 
with arsenic and cadmium emissions driving the risks. The EPA estimates 
that the incidence of cancer due to inhalation exposures could be up to 
0.005 excess cancer cases per year, or 1 case approximately every 200 
years. About 94,000 people could face an increased cancer risk greater 
than 1-in-1 million due to inhalation exposure to allowable HAP 
emissions from these source categories and approximately 2,500 people 
could face an increased risk greater than 10-in-1 million and up to 
100-in-1 million due to allowable emissions.
    The risk assessment estimates that the maximum chronic non-cancer 
TOSHI from inhalation exposure values is up to 40, driven by allowable 
manganese emissions. Approximately 11,000 people are estimated to have 
exposure to HI levels greater than 1.
c. Acceptability Determination
    In determining whether risks are acceptable for this source 
category, the EPA considered all available health information and risk 
estimation uncertainty as described above.
    The risk results indicate that the allowable inhalation cancer 
risks to the individual most exposed are up to but no greater than 
approximately 100-in-1 million, which is the presumptive limit of 
acceptability. The MIR based on actual emissions is 20-in-1 million, 
well below the presumptive limit. The maximum chronic exposure to 
manganese exceeds the human health dose-response value for manganese by 
a factor of approximately 4 based on actual emissions. For allowable 
emissions, exposures could exceed the health value up to a factor of 
approximately 40. The noncancer hazard is driven by manganese 
emissions.
    Neither the acute risk nor the risks from the multipathway 
assessment exceeded levels of concern, however the EPA does note that 
the refined multipathway exposure estimate for mercury was at the level 
of the RfD.
    The EPA proposes that the risks are unacceptable for the following 
reasons. First, the EPA considered the fact that the noncancer hazard 
quotient ranges from 4 based on actual emissions to 40 based on 
allowable emissions. The EPA has not established under section 112 of 
the CAA a numerical range for risk acceptability for noncancer effects 
as it has with carcinogens, nor has it determined that there is a 
bright line above which acceptability is denied. However, the Agency 
has established that, as exposure increases above a reference level (as 
indicated by a HQ or TOSHI greater than 1), confidence that the public 
will not experience adverse health effects decreases and the likelihood 
that an effect will occur increases. For the ferroalloys source 
category, the potential for members of the public to be exposed to 
manganese at concentrations up to 40 times the MRL reduces the Agency's 
confidence that the public is protected from adverse health effects and 
diminishes the Agency's ability to determine that such exposures are 
acceptable. Second, the EPA considered the fact that the cancer risk 
estimate for actual emissions is 20-in-1 million and up to 100-in-1 
million for allowable emissions. While 20-in-1 million is well within 
the acceptable range, risks from allowable emissions are at the upper 
end of the range of acceptability. This fact, combined with

[[Page 60270]]

the fact that the noncancer hazard is up to 40 times the MRL and the 
refined multipathway HQ for mercury is at the RfD, leads the agency to 
conclude that the risk from this source category is unacceptable.

2. Proposed Controls to Address Unacceptable Risks

a. Stack Emissions
    In order to address the unacceptable risk from this source 
category, we evaluated the potential to reduce MACT-allowable stack 
emissions, which resulted in a cancer MIR of 100-in-1 million, 
primarily due to allowable stack emissions of arsenic and cadmium and 
contributed significantly to the chronic noncancer TOSHI of 40, 
primarily due to allowable stack emissions of manganese. Our analysis 
determined that we could lower the existing particulate matter emission 
limits by approximately 50 percent for furnace stack emissions, by 80 
percent for crushing and screening stack emissions and by 98 percent 
for the metal oxygen refining (MOR) process, which would help reduce 
risk to an acceptable level. As explained above, the MOR is a major 
driver of the allowable risks. Therefore, by lowering the MOR limit by 
98 percent, this results in a large reduction in the allowable risks.
    For the reasons described above, under the authority of CAA section 
112(f)(2), we propose particulate matter emission limits for the stacks 
at the following levels: 4.0 mg/dscm for new or reconstructed electric 
arc furnaces and 25 mg/dscm for existing electric arc furnaces. In the 
2011 proposal, we proposed a limit of 3.9 mg/dscm for any new, 
reconstructed or existing MOR process and 13 mg/dscm for any new, 
reconstructed or existing crushing and screening equipment. We believe 
sources can achieve the limits we are proposing today with existing 
controls. These emissions limits will substantially reduce potential 
risks due to allowable emissions from the stacks. We propose that 
compliance for all existing and new sources will be demonstrated by 
periodic stack testing, along with installation and continuous 
operation of bag leak detection systems for both new and existing 
sources that have baghouses, and continuous monitoring of liquid flow 
rate and pressure drop for sources controlled with wet scrubbers.
b. Process Fugitive Emissions Sources
    Process fugitive sources are partially controlled by the existing 
MACT rule via a shop building opacity standard; however, that standard 
was only intended to address tapping process fugitives generated under 
``normal'' tapping process operating conditions. Casting and crushing 
and screening process fugitives in the furnace building were not 
included. Under the authority of section 112 of the Act, which allows 
the use of measures to enclose systems or processes to eliminate 
emissions and measures to collect, capture or treat such pollutants 
when released from a process, stack, storage, or fugitive emissions 
point, we evaluated options to achieve improved emissions capture. In 
the 2011 proposal, we proposed full-enclosure with negative pressure 
and viewed local capture as not being an appropriate method of risk 
reduction. However, based on comments and other information gathered 
since the 2011 proposal and after further review and analyses of 
available information, we reevaluated whether the necessary risk 
reduction could be accomplished by an alternative approach to control 
fugitive emissions based on enhanced local capture of emissions. This 
control approach would include a combination of primary and secondary 
hoods that effectively capture process fugitive emissions and vents 
those emissions to PM control devices. The secondary capture would 
include hooding at the roof-lines whereby remaining fugitives are 
collected and vented to control devices. As described further under the 
technology review section of this preamble, this approach (based on 
enhanced local capture and control of process fugitives, using primary 
and secondary hoods), will effectively reduce process fugitive 
emissions. We conclude that this approach will achieve substantial 
reductions of process fugitive emissions (approximately 95 percent 
capture and control of fugitive emissions) and will also substantially 
reduce the estimated risks due to these emissions. Therefore, under 
section 112(f) of the CAA we are proposing this control option that is 
based on enhanced capture of fugitive emissions using primary hoods 
(that capture process fugitive emissions near the source) and secondary 
capture of fugitives (which would capture remaining fugitive emissions 
near the roof-line) and includes a tight opacity limit of 8 percent to 
ensure fugitives are effectively captured and controlled. We are 
proposing that the facilities in this source category must install and 
maintain a process fugitives capture system that is designed to capture 
and control 95 percent or more of the process fugitive emissions. This 
is the same exact control approach described in more detail under the 
technology review section of today's notice and the same control 
approach that we are proposing under section 112(d)(6) of the Act, as 
described below. We estimate that this control approach will achieve 
about 95 percent capture of process fugitive emissions and will achieve 
about 77 tpy reduction in HAP metals emissions and will substantially 
reduce risks due to process fugitive emissions. We conclude that 
achieving these reductions is the level of control needed to address 
the unacceptable risks due to HAP emissions from the source category.
c. Results of the Post-control Risk Assessment
    The results of the post-control chronic inhalation cancer risk 
assessment indicate that the maximum individual lifetime cancer risk 
posed by these two facilities, after the implementation of the proposed 
controls, could be up to 10-in-1 million, reduced from 20-in-1 million 
(i.e., pre-controls), with an estimated reduction in cancer incidence 
to 0.001 excess cancer cases per year, reduced from 0.002 excess cancer 
cases per year. In addition, the number of people estimated to have a 
cancer risk greater than or equal to 1-in-1 million would be reduced 
from 31,000 to 6,600. The results of the post-control assessment also 
indicate that the maximum chronic noncancer inhalation TOSHI value 
would be reduced to 1, from the baseline estimate of 4. The number of 
people estimated to have a TOSHI greater than 1 would be reduced from 
1,500 to 0. We also estimate that after the implementation of controls, 
the maximum worst-case acute HQ value would be reduced from 1 to less 
than 1 (based on REL values).
    Considering post-control emissions of multipathway HAP, mercury 
emissions would be reduced by approximately 3 lbs/yr, lead would be 
reduced by about 1,600 lbs/yr, POM emissions would be reduced by 
approximately 5,200 lbs/yr, cadmium would be reduced by about 150 lbs/
yr and dioxins and furans would be reduced by about 0.002 lbs/yr from 
the baseline emission rates.
3. Ample Margin of Safety Analysis
    Under the ample margin of safety analysis, we again consider all of 
the health factors evaluated in the acceptability determination and 
evaluate the cost and feasibility of available control technologies and 
other measures (including the controls, measures and costs reviewed 
under the technology review) that could be applied in this source 
category to further reduce the risks due to

[[Page 60271]]

emissions of HAP identified in our risk assessment.
    We estimate that the actions proposed under CAA section 112(f)(2), 
as described above to address unacceptable risks, will reduce the MIR 
associated with arsenic, nickel, chromium and PAHs from 20-in-1 million 
to 10-in-1 million for actual emissions. The cancer incidence will be 
reduced from 0.002 to 0.001 cases per year and the number of people 
estimated to have cancer risks greater than 1-in-1 million will be 
reduced, from 31,000 people to 6,600 people. The chronic noncancer 
inhalation TOSHI will be reduced from 4 to 1 and the number of people 
exposed to a TOSHI level greater than 1 will be reduced from 1,500 
people to 0. In addition, the potential multipathway impacts will be 
reduced.
    Based on all of the above information, we conclude that the risks 
after implementation of the proposed controls are acceptable. Based on 
our research and analysis, we did not identify any cost-effective 
controls beyond those proposed above that would achieve further 
reduction in risk. While in theory the 2011 proposed approach of total 
enclosure would provide some additional risk reduction, the additional 
risk reduction is minimal and, as noted, we have substantial doubts 
that it would be feasible for these facilities. Therefore we conclude 
that the controls to achieve acceptable risks (described above) will 
also provide an ample margin of safety to protect public health.

D. What are the results and proposed decisions based on our technology 
review?

1. Metal HAP Emissions Limits From Stacks
    As mentioned in the previous section, the available test data from 
the five furnaces located at two facilities indicate that all of these 
furnaces have PM emission levels that are well below their respective 
emission limits (the emission limits are based on size and product 
being produced in the furnace) in the 1999 MACT rule. These findings 
demonstrate that the add-on emission control technologies (venturi 
scrubber, positive pressure fabric filter, negative pressure fabric 
filter) used to control emissions from the furnaces are quite effective 
in reducing particulate matter (used as a surrogate for metal HAP) and 
that all of the facilities have emissions well below the current 
limits.
    Under section 112(d)(6) of the Clean Air Act (CAA), we are required 
to revise emission standards, taking into account developments in 
practices, processes and control technologies. The particulate matter 
(PM) emissions, used as a surrogate for metal HAP, that were reported 
by the industry in response to the 2010 ICR were far below the level 
specified in the current NESHAP, indicating improvements in the control 
of PM emissions since promulgation of the current NESHAP. We re-
evaluated the data received in 2010, along with additional data 
received in 2012 and 2013, to determine whether it is appropriate to 
propose revised emissions limits for PM from the furnace process vents. 
The re-evaluation of the PM limits was completed using available PM 
emissions test data from all the furnaces and consideration of 
variability across those data. More details regarding the available PM 
data and this re-evaluation are provided in the Revised Technology 
Review for the Ferroalloys Production Source Category for the 
Supplemental Proposal, which is available in the docket. Unlike PAH and 
mercury stack data, we did not see significant differences in 
variability of the PM data sets depending on product produced (e.g., 
ferromanganese or silicomanganese). Therefore, we are not proposing to 
subcategorize the PM stack limits based on product type.
    Based on this analysis, we determined that it is appropriate to 
propose revised PM limits for the furnaces and that the revised 
existing source furnace stack PM emissions limit should be 25 
milligrams per dry standard cubic meter (mg/dscm). Therefore, we are 
proposing a revised emissions limit of 25 mg/dscm for existing furnace 
stack PM emissions in this supplemental proposal. This emission limit 
is slightly higher than the existing source furnace PM emission limit 
of 24 mg/dscm that we proposed in the 2011 proposal. The revised 
emissions limit is based on more data than the previous proposed limit. 
No additional add-on controls are expected to be required by the 
facilities to meet the revised existing source limit of 25 mg/dscm. 
However, this revised limit would result in significantly lower 
``allowable'' PM emissions from the source category compared to the 
level of emissions allowed by the 1999 MACT rule and would help prevent 
any emissions increases. To demonstrate compliance, we propose these 
sources would be required to conduct periodic performance testing and 
develop and operate according to a baghouse operating plan or 
continuously monitor venturi scrubber operating parameters. We also 
propose that furnace baghouses would be required to be equipped with 
bag leak detection systems (BLDS).
    The revised new source PM standard for furnaces was determined by 
evaluating the available data from the best performing furnace (which 
was determined to be furnace 2 at Felman). The new source MACT 
limit was determined to be 4.0 mg/dscm based on data from furnace 
2 and was selected as the proposed MACT emissions limit for PM 
from new and reconstructed source furnace stacks.
    The PM emission limit for the local ventilation control device 
outlet was also re-evaluated using compliance test data and test data 
from the 2012 ICR. A local ventilation control device is used to 
capture tapping, casting, or ladle treatment emissions and direct them 
to a control device other than one associated with the furnace. The 
2011 proposal included a proposed PM limit for the local ventilation 
control device that was based on PM data from the furnaces. After the 
2011 proposal, we received test data from 3 different emissions tests 
(for a total of 9 test runs) specifically for this local ventilation 
source. We determined these data were more appropriate for the 
development of a limit for this source than the furnace data we had 
used for the 2011 proposal. There is currently only one local 
ventilation control device outlet emissions source in this source 
category.
    Using the new data for the one existing local ventilation source, 
we calculated a revised emissions limit of 4.0 mg/dscm and determined 
that this was an appropriate emissions limit for this source. Therefore 
we are proposing this emissions limit of 4.0 mg/dscm for existing, new 
and reconstructed local ventilation control device emissions sources.
2. Metal HAP Emissions From Process Fugitives
    In the 2011 proposal, we concluded that a proposed requirement for 
sources to enclose the furnace building, collect fugitive emissions 
such that the furnace building is maintained under negative pressure 
and duct those emissions to a control device represented an advance in 
emissions control measures since the Ferroalloys Production NESHAP was 
originally promulgated in 1999. Commenters on the 2011 proposal 
disagreed with our assessment. Based on these comments, we reassessed 
the proposed requirement for negative pressure ventilation and 
determined that the installation and operation of the proposed system 
may not be feasible and would likely be very costly. For example, the 
recent secondary lead NESHAP requires use of such a system, but we 
recognize that a much smaller volume of air must be evacuated at 
secondary lead facilities because of their

[[Page 60272]]

smaller size compared to ferroalloy facilities. We agree that we had 
underestimated the costs of such negative pressure systems and we have 
provided updated cost analyses.
    Commenters also raised concerns about worker safety and comfort in 
designing and operating such systems based on historical examples. We 
believe that such issues can be overcome with proper ventilation design 
and installation of air conditioning systems and other steps to ensure 
these issues are not a problem. However, after further review and 
evaluation we conclude that it would be quite costly for these 
facilities to become fully enclosed with negative pressure and achieve 
the appropriate ventilation and conditioning of indoor air.
    Going back to the original goal of identifying advances in 
emissions control measures since the Ferroalloys Production NESHAP was 
promulgated in 1999, we have arrived at a different conclusion than we 
described in the 2011 proposal. We re-evaluated the costs and 
operational feasibility associated with the full building enclosure 
with negative pressure that we proposed in 2011. We consulted with 
ventilation experts who have worked with hot process fugitives similar 
to those found in the ferroalloys industry (e.g., electric arc furnace 
steel mini-mills and secondary lead smelters). We determined that 
substantially more air flow, air exchanges, ductwork, fans and control 
devices and supporting structural improvements would be needed 
(compared to what we had estimated in the 2011 proposal) to achieve 
negative pressure and also ensure adequate ventilation and air quality 
in these large furnace buildings. Therefore, we determined that the 
proposed negative pressure approach presented in the 2011 proposal 
would be much more expensive than what we had estimated in 2011 and may 
not be feasible for these facilities.
    We also evaluated another option based on enhanced capture of the 
process fugitive emissions using a combination of effective local 
capture with primary hooding close to the emissions sources and 
secondary capture of remaining fugitives with roof-line capture hoods 
and control devices. These buildings are currently designed such that 
fugitive emissions that are not captured by the primary hoods flow 
upward with a natural draft to the open roof vents and are vented to 
the atmosphere uncontrolled. Under our enhanced control scenario, the 
primary capture close to the emissions sources would be significantly 
improved with effective local hooding and ventilation and the remaining 
fugitive emissions (that are not captured by the primary hoods) would 
be drawn up to the roof-line and captured with secondary hooding and 
vented to control devices.
    In cases where additional collection of fugitives from the roof 
monitors is needed to comply with building opacity limits, fume 
collection areas may be isolated via baffles (so the area above the 
furnace where fumes collect may be kept separated from ``empty'' spaces 
in large buildings) and roof monitors over fume collection areas can be 
sealed and directed to control devices. The fugitive emission capture 
system should achieve inflow at the building floor, but outflow toward 
the roof where most of the remaining fugitives would be captured by the 
secondary hooding. We conclude that a rigorous, systematic examination 
of the ventilation requirements throughout the building is the key to 
developing a fugitive emission capture system (consisting of primary 
hoods, secondary hoods, enclosures and/or building ventilation ducted 
to particulate matter control devices) that can be designed and 
operated to achieve very low levels of fugitive emissions. Such an 
evaluation considers worker health, safety and comfort and it is 
designed to optimize existing ventilation options (fan capacity and 
hood design) and add additional capture options to meet specified 
design criteria determined through the evaluation process. Thus, we 
conclude that an enhanced capture system based on these design 
principles does represent an advancement in technology. We estimate 
that this control scenario would capture about 95 percent of the 
process fugitive emissions and vent those emissions to PM control 
devices. This enhanced local capture option is described in more detail 
in the Revised Technology Review document and in the Cost Impacts of 
Control Options to Address Fugitive HAP Emissions for the Ferroalloys 
Production NESHAP Supplemental Proposal document (Cost Impacts 
document) which are available in the docket.
    Under this control option, the cost elements vary by plant and 
furnace and include the following:
     Curtains or doors surrounding furnace tops to contain 
fugitive emissions;
     Improvements to hoods collecting tapping emissions;
     Upgrade fans to improve the airflow of fabric filters 
controlling fugitive emissions;
     Addition of ``secondary capture'' or additional hoods to 
capture emissions from tapping platforms or crucibles;
     Addition of fugitives capture for casting operations;
     Improvement of existing control devices or addition of 
fabric filters; and
     Addition of rooftop ventilation, in which fugitive 
emissions escaping local capture are collected in the roof canopy over 
process areas through addition of partitions, hoods, and then directed 
through ducts to control devices.
    We estimate the total capital costs of installing the required 
ductwork, fans and control devices under the enhanced capture option 
(which is described above and in more detail in the Cost Impacts 
document) to be $37.6 million and the total annualized cost to be $7.1 
million for the two plants. We estimate that this option would reduce 
metal HAP emissions by 75 tons per year, resulting in a cost per ton of 
metal HAP removed to be $94,600 per ton ($47 per pound). The total 
estimated HAP reduction for the enhanced capture option is 77 tons per 
year at a cost per ton of $91,900 ($46 per pound). We also estimate 
that this option would achieve PM emission reductions of 229 tons per 
year, resulting in cost per ton of PM removed of $30,900 per ton and 
achieve PM2.5 emission reductions of 48 tons per year, 
resulting in a cost per ton of PM2.5 removal of $147,000 per 
ton. We believe these controls for process fugitive HAP emissions 
(described above), which are based on enhanced capture (with primary 
and secondary hooding) are feasible for the Ferroalloys Production 
source category from a technical standpoint and are cost effective. 
This cost effectiveness is in the range of cost effectiveness for PM 
and HAP metals from other previous rules. However, it is important to 
note that there is no bright line for determining cost-effectiveness 
for HAP metals. Each rulemaking is different and various factors must 
be considered. Some of the other factors we consider when making 
decisions whether to establish standards beyond the floor under section 
112(d)(2) or under section 112(d)(6) include, but are not limited to, 
the following: which of the HAP metals are being reduced and by how 
much; total capital costs; annual costs; and costs compared to total 
revenues (e.g., costs to revenue ratios).
    We also re-evaluated the option based on building ventilation as 
described in the 2011 proposal. This control option involves 
installation of full building ventilation at negative pressure for 
furnace buildings instead of installing fugitive controls on individual 
tapping and casting operations. This option would require installation 
of ductwork

[[Page 60273]]

from the roof vents of furnace buildings, additional fans, structural 
repairs to buildings and a new fabric filter for each building. Both 
Eramet and Felman provided extensive comments and information regarding 
implementation of building ventilation, including cost estimates based 
on their own engineering analyses. We thoroughly reviewed the comments 
and information provided by the companies along with information 
gathered from other sources, and then revised our costs analyses 
accordingly for this supplemental proposal.
    We estimate that the full building enclosure option would reduce PM 
emissions from the facilities by 252 tons per year (and total HAP 
emissions by 83 tons per year). The total estimated capital cost for 
these fugitive controls is $61 million. Annualized capital cost and 
operational and maintenance costs are estimated at $19 million per 
year, which results in an estimated cost per ton of metal HAP removed 
of $226,000 per ton. We also estimate that this option would achieve PM 
emission reductions of 252 tons, resulting in cost per ton of PM 
removed of $74,200 per ton and achieve PM2.5 emission 
reductions of 53 tons, resulting in a cost per ton of PM2.5 
removal of $353,000 per ton. The incremental cost effectiveness 
comparing the enhanced capture option to the building ventilation 
option is $501,000 per ton of PM removed, $2.4 million per ton of 
PM2.5 removed and $2.2 million per ton of HAP removed.
    Based on these analyses, we conclude that the full-building 
enclosure option with negative pressure may not be feasible and would 
have significant economic impacts on the facilities (including 
potential closure for one or more facilities). However, we conclude 
that the enhanced local capture option is a feasible and cost-effective 
approach to achieve significant reductions in fugitive HAP emissions 
and will achieve almost as much reductions as the full-building 
enclosure option (229 vs 252 tons PM reductions) thus achieving most of 
the risk reductions. In light of the technical feasibility and cost 
effectiveness of the enhanced capture options, we are proposing the 
enhanced capture option under the authority of section 112(d)(6) of the 
CAA.
    In the 2011 proposal, we included a requirement that emissions 
exiting from a shop building may not exceed more than 10 percent 
opacity for more than one 6-minute period, to be demonstrated every 5 
years as part of the periodic required performance tests. For day-to-
day continuous monitoring to demonstrate compliance with the proposed 
shop building requirements, the 2011 proposal relied on achieving the 
requirement to maintain the shop building at negative pressure to at 
least 0.007 inches of water. This was to be supplemented by operation 
and work practice standards that required preparation of a process 
fugitive emissions ventilation plan for each shop building, which would 
include schematics with design parameters (e.g., air flow and static 
pressure) of the ventilation system. The source would conduct a 
baseline survey to verify that building air supply and exhaust are 
balanced and the building will be maintained under at least 0.007 
inches of water. Such plan would identify critical maintenance 
activities and schedules, be submitted to the permitting authority and 
incorporated into the source's operating permit. The baseline survey 
would be repeated every 5 years or following significant changes to the 
ventilation system.
    With the move to the proposed enhanced local capture alternative, 
we believe that more frequent opacity monitoring based on an average of 
8 percent opacity at all times, is appropriate to demonstrate 
compliance with the process fugitives standards. We propose that if the 
average opacity reading from the shop building is greater than 8 
percent opacity during an observed furnace process cycle, an additional 
two more furnace process cycles must be observed such that the average 
opacity during the entire observation period is less than 7 percent 
opacity. A furnace process cycle means the period in which the furnace 
is tapped to the time in which the furnace is tapped again and includes 
periods of charging, smelting, tapping, casting and ladle raking. We 
also propose that at no time during operation may any two consecutive 
6-minute block opacity readings be greater than 20 percent opacity. We 
believe that the longer averaging time for this new opacity limit 
(furnace process cycle vs. individual 6-minute averages) addresses 
concerns that small variations in an otherwise well-controlled furnace 
cycle could result in violations of the opacity standard. The proposed 
20 percent ceiling ensures that there are no acute events that could 
adversely affect public health. Finally, the lower limit (8 vs. 10 
percent opacity) also reflects that sources should achieve lower 
overall emissions over a longer averaging period. We propose that 
sources be required to conduct opacity observations at least once per 
week for each operating furnace and each MOR operation. Similar to the 
2011 proposal, continuous monitoring of key ventilation operating 
system parameters and periodic inspections of the ventilation systems 
would ensure that the ventilation systems are operating as designed.
    Also, similar to the 2011 proposal, we believe that the source 
should demonstrate that the overall design of the ventilation system is 
adequate to achieve the proposed standards. We propose that the 
facilities in this source category must maintain a process fugitives 
capture system that is designed to collect 95 percent or more of the 
process fugitive emissions from furnace operations, casting MOR 
process, ladle raking and slag skimming and crushing and screening 
operations and convey the collected emissions to a control device that 
meets specified emission limits and the proposed opacity limits. We 
believe that if the source designs the plan according to the most 
recent (at the time of construction) ventilation design principles 
recommended by the American Conference of Governmental Industrial 
Hygienists (ACHIH), includes detailed schematics of the ventilation 
system design, addresses variables that affect capture efficiency such 
as cross drafts and describes protocol or design characteristics to 
minimize such events and identifies monitoring and maintenance steps, 
the plan will be capable of ensuring the system is properly designed 
and continues to operate as designed. We would continue to require that 
this plan be submitted to the permitting authority, incorporated into 
the source's operating permit and updated every 5 years or when there 
is a significant change in variables that affect process fugitive 
emissions ventilation design. This list of design criteria, coupled 
with the requirement for frequent opacity observations and operating 
parameter monitoring will result in enforceable requirements. We 
recognize that other design requirements and/or more frequent opacity 
observations may yield more compliance certainty, but incur greater 
costs and not result in measurable decreases in emissions. However, we 
request comment on other measures that could be considered to 
demonstrate that well designed (e.g., at least 95 percent overall 
capture of process fugitive emissions) plans are developed and 
maintained. We request that such comments include costs, measurement 
techniques or other information to evaluate their efficacy.

E. What other actions are we proposing?

    In addition to the proposed actions described above, we re-
evaluated compliance requirements associated with the 2011 proposed 
amendments to

[[Page 60274]]

determine whether we should make changes to those proposed amendments. 
Based on this re-evaluation, we are proposing the following changes to 
what was proposed in the 2011 proposal.
1. Stack Emission Limits
    In response to public comments, we revisited the format of the 
stack emission limits. We concluded that a concentration-based limit is 
still appropriate, but we agree that the proposed CO2 
concentration correction poses a problem under certain control device 
configurations. While such a concentration correction is appropriate 
for combustion sources such as boilers, we agree that its use in the 
context of ferroalloys production is not helpful. The PM stack limits 
proposed above do not include a CO2 correction.
2. Emissions Averaging
    As described above, we have decided to retain a concentration 
format for the emissions limits for the stacks but we are not retaining 
the emissions averaging provision in this supplemental proposal that we 
had proposed in 2011. We believe a concentration format is the best 
format for this NESHAP and we have concluded that it is not the best 
format to use under an emissions averaging option. We are concerned 
that emissions from a large furnace emitting a lower than average 
concentration could still emit more emissions than a small furnace with 
a higher than average concentration. This could result in a net 
increase in emissions from the two furnaces compared to their emissions 
if they were not allowed to average emissions. For this reason, we are 
proposing not to include the emissions averaging provisions in the 
rule, which is a change from the 2011 proposal.
3. Fenceline Monitoring Alternative
    In the 2011 proposal, we assumed there could be control measures 
other than maintaining the furnace buildings under negative pressure 
that would achieve equivalent emissions reductions. Therefore, to 
provide some flexibility to facilities regarding how to achieve the 
reductions of fugitive emissions, in lieu of building the full 
enclosure and evacuation system described in the 2011 proposal, we 
proposed that sources could demonstrate compliance with an alternative 
approach by conducting fenceline monitoring and demonstrate that the 
ambient concentrations of manganese at their facility boundary remain 
at levels no more than 0.1 [mu]g/m\3\ on a 60-day rolling average. 
However, at this time, we believe that the proposed enhanced local 
capture option described in this supplemental proposal incorporates the 
features anticipated in a non-negative pressure building option and 
contains compliance requirements (based on meeting a tight opacity 
limit and other requirements) that would assess emissions at the point 
of the maximum output, that is, from the roof monitor of the 
ferroalloys production building. Furthermore, we determined there were 
various issues associated with fenceline monitoring at facilities 
within this source category, including highly variable wind patterns, 
uncertainties as to how to account for background concentrations and 
road dust and the large difference between emissions release heights 
(from the high roof vents and stacks) compared to heights where 
fenceline monitors would be located (near ground level). Therefore, we 
are proposing to not include fenceline monitoring in the final rule as 
an alternative method to demonstrate compliance with a specific ambient 
level as was described in the 2011 proposal. We believe the proposed 
tight opacity limit (which would be measured at the emissions sources), 
along with the proposed requirements to install, operate and maintain 
effective fugitive capture and control systems, emissions limits for 
the stacks and various parametric monitoring requirements, are 
appropriate control requirements to ensure effective capture and 
control of emissions. However, as described in Section V.I. of this 
Notice, we are seeking comments regarding other possible options to 
monitor fugitive emissions, including fenceline monitoring as a tool to 
monitor trends in ambient concentrations at these locations and to use 
this information (along with meteorological data and modeling tools) to 
attempt to quantify trends in emissions that are leaving and entering 
the facility property.
4. Startup, Shutdown, Malfunction
    In the 2011 proposal, we proposed to eliminate two provisions that 
exempt sources from the requirement to comply with the otherwise 
applicable CAA section 112(d) emission standards during periods of SSM. 
We also included provisions for affirmative defense to civil penalties 
for violations of emission standards caused by malfunctions. Periods of 
startup, normal operations, and shutdown are all predictable and 
routine aspects of a source's operations. However, by contrast, 
malfunction is defined as a ``sudden, infrequent, and not reasonably 
preventable failure of air pollution control and monitoring equipment, 
process equipment or a process to operate in a normal or usual manner . 
. .'' (40 CFR 63.2). As explained in the 2011 proposal, the EPA 
interprets CAA section 112 as not requiring emissions that occur during 
periods of malfunction to be factored into development of CAA section 
112 standards. Under section 112, emissions standards for new sources 
must be no less stringent than the level ``achieved'' by the best 
controlled similar source and for existing sources generally must be no 
less stringent than the average emission limitation ``achieved'' by the 
best performing 12 percent of sources in the category. There is nothing 
in section 112 that directs the Agency to consider malfunctions in 
determining the level ``achieved'' by the best performing sources when 
setting emission standards. As the DC Circuit has recognized, the 
phrase ``average emissions limitation achieved by the best performing 
12 percent of'' sources ``says nothing about how the performance of the 
best units is to be calculated.'' Nat'l Ass'n of Clean Water Agencies 
v. EPA, 734 F.3d 1115, 1141 (D.C. Cir. 2013). While the EPA accounts 
for variability in setting emissions standards, nothing in section 112 
requires the Agency to consider malfunctions as part of that analysis. 
A malfunction should not be treated in the same manner as the type of 
variation in performance that occurs during routine operations of a 
source. A malfunction is a failure of the source to perform in a 
``normal or usual manner'' and no statutory language compels the EPA to 
consider such events in setting section 112 standards.
    Further, accounting for malfunctions in setting emission standards 
would be difficult, if not impossible, given the myriad different types 
of malfunctions that can occur across all sources in the category and 
given the difficulties associated with predicting or accounting for the 
frequency, degree and duration of various malfunctions that might 
occur. As such, the performance of units that are malfunctioning is not 
``reasonably'' foreseeable. See, e.g., Sierra Club v. EPA, 167 F.3d 
658, 662 (D.C. Cir. 1999) (``The EPA typically has wide latitude in 
determining the extent of data-gathering necessary to solve a problem. 
We generally defer to an agency's decision to proceed on the basis of 
imperfect scientific information, rather than to `invest the resources 
to conduct the perfect study.' '') See also, Weyerhaeuser v. Costle, 
590 F.2d 1011, 1058 (D.C. Cir. 1978) (``In the nature of things, no 
general limit, individual permit, or even any upset provision can 
anticipate all upset situations. After a

[[Page 60275]]

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. As 
such, 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 section 112 to avoid such a 
result. The EPA's approach to malfunctions is consistent with 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 standard was, in fact, ``sudden, infrequent, not 
reasonably preventable'' and was not instead ``caused in part by poor 
maintenance or careless operation.'' 40 CFR Sec.  63.2 (definition of 
malfunction).
    Further, to the extent the EPA files an enforcement action against 
a source for violation of an emission standard, 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.
    As noted above, the 2011 proposal included an affirmative defense 
to civil penalties for violations caused by malfunctions. EPA included 
the affirmative defense in the 2011 proposal as it had in several prior 
rules in an effort to create a system that incorporates some 
flexibility, recognizing that there is a tension, inherent in many 
types of air regulation, to ensure adequate compliance while 
simultaneously recognizing that despite the most diligent of efforts, 
emission standards may be violated under circumstances entirely beyond 
the control of the source. Although the EPA recognized that its case-
by-case enforcement discretion provides sufficient flexibility in these 
circumstances, it included the affirmative defense in the 2011 proposal 
and in several prior rules to provide a more formalized approach and 
more regulatory clarity. See Weyerhaeuser Co. v. Costle, 590 F.2d 1011, 
1057-58 (D.C. Cir. 1978) (holding that an informal case-by-case 
enforcement discretion approach is adequate); but see Marathon Oil Co. 
v. EPA, 564 F.2d 1253, 1272-73 (9th Cir. 1977) (requiring a more 
formalized approach to consideration of ``upsets beyond the control of 
the permit holder.''). Under the EPA's regulatory affirmative defense 
provisions, if a source could demonstrate in a judicial or 
administrative proceeding that it had met the requirements of the 
affirmative defense in the regulation, civil penalties would not be 
assessed. The United States Court of Appeals for the District of 
Columbia Circuit vacated an affirmative defense in one of the EPA's 
Section 112 regulations. NRDC v. EPA, 749 F.3d 1055 No. 10-1371 (D.C. 
Cir., 2014) (vacating affirmative defense provisions in Section 112 
rule establishing emission standards for Portland cement kilns). The 
court found that the EPA lacked authority to establish an affirmative 
defense for private civil suits and held that under the CAA, the 
authority to determine civil penalty amounts in such cases lies 
exclusively with the courts, not the EPA. Specifically, the Court 
found: ``As the language of the statute makes clear, the courts 
determine, on a case-by-case basis, whether civil penalties are 
`appropriate.' '' See NRDC at *21 (``[U]nder this statute, deciding 
whether penalties are `appropriate' in a given private civil suit is a 
job for the courts, not EPA.''). In light of NRDC, the EPA is 
withdrawing its proposal to include a regulatory affirmative defense 
provision in this rulemaking and in this proposal has eliminated 
sections 63.1627 and 63.1662 (the affirmative defense provisions in the 
proposed rule published in the Federal Register on November 23, 2011 
(76 FR 72508)). As explained above, if a source is unable to comply 
with emissions standards as a result of a malfunction, the EPA may use 
its case-by-case enforcement discretion to provide flexibility, as 
appropriate. Further, as the DC Circuit recognized, in an EPA or 
citizen enforcement action, the court has the discretion to consider 
any defense raised and determine whether penalties are appropriate. Cf. 
NRDC at *24. (arguments that violation were caused by unavoidable 
technology failure can be made to the courts in future civil cases when 
the issue arises). The same logic applies to EPA administrative 
enforcement actions.

F. What compliance dates are we proposing?

    The proposed changes to the 2011 proposal that are set out in this 
supplementary proposal will not change the compliance dates proposed. 
We continue to propose that facilities must comply with the changes set 
out in this supplementary proposal (which are being proposed under CAA 
sections 112(d)(2), 112(d)(3), 112(d)(6) and 112(f)(2) for all affected 
sources), no later than 2 years after the effective date of the final 
rule. We find that 2 years are necessary to complete the installation 
of the enhanced local capture system and other controls. In the period 
between the effective date of this rule and the compliance date, 
existing sources would continue to comply with the existing 
requirements specified in Sec. Sec.  63.1650 through 63.1661, which 
will protect the health of persons from imminent endangerment.

V. Summary of the Revised Cost, Environmental and Economic Impacts

A. What are the affected sources?

    We maintain, as at the 2011 proposal, that the two manganese 
ferroalloys production facilities currently operating in the United 
States will be affected by these proposed amendments. We do not know of 
any new facilities that are expected to be constructed in the 
foreseeable future. However, there is one other facility that has a 
permit to produce ferromanganese or silicomanganese in an electric arc 
furnace, but it is not doing so at present. It is possible, however, 
that this facility could resume production or another non-manganese 
ferroalloy producer

[[Page 60276]]

could decide to commence production of ferromanganese or 
silicomanganese. Given this uncertainty, our impact analysis is focused 
on the two existing sources that are currently operating.

B. What are the air quality impacts?

    The EPA revised the estimated emissions reductions that are 
expected to result from the proposed amendments to the 1999 NESHAP 
based on the proposed changes in this supplemental proposal. A detailed 
documentation of the analysis can be found in the Cost Impacts 
document, which is available in the docket.
    As noted in the 2011 proposal, emissions of metal HAP from 
ferroalloys production sources have declined in recent years, primarily 
as the result of state actions and also due to the industry's own 
initiative. The proposed amendments in this supplemental proposal would 
cut HAP emissions (primarily particulate metal HAP such as manganese, 
arsenic and nickel) by about 60 percent from their current levels. 
Under the revised proposed emissions standards for process fugitives 
emissions from the furnace building, we estimate that the HAP emissions 
reductions would be 77 tpy, including significant reductions of 
manganese.
    As noted in the 2011 proposal, based on the emissions data 
available to the EPA, we believe that both facilities will be able to 
comply with the proposed emissions limits for HCl without additional 
controls. Based on the analyses presented today, we also anticipate 
that both facilities will be able to comply with the proposed emission 
limits for mercury and PAH without additional controls.

C. What are the cost impacts?

    Under the revised proposed amendments, ferroalloys production 
facilities are expected to incur costs for the design of a local 
ventilation system, resulting in a site-specific local ventilation plan 
and installation of custom hoods and ventilation equipment and 
additional control devices to manage the air flows generated by the 
enhanced capture systems. There would also be capital costs associated 
with installing new or improved continuous monitoring systems, 
including installation of BLDS on the furnace baghouses that are not 
currently equipped with these systems.
    The revised capital costs for each facility were estimated based on 
the projected number and types of upgrades required. The specific 
enhancements for each facility were selected for cost estimation based 
on estimates directly provided by the facilities based on their 
engineering analyses and discussions with the EPA. The Cost Impacts 
document includes a complete description of the revised cost estimate 
methods used for this analysis and is available in the docket.
    Cost elements vary by plant and furnace and include the following 
elements:
     Curtains or doors surrounding furnace tops to contain 
fugitive emissions;
     Improvements to hoods collecting tapping emissions;
     Upgraded fans to improve the airflow of fabric filters 
controlling fugitive emissions;
     Addition of ``secondary capture'' or additional hoods to 
capture emissions from tapping platforms or crucibles;
     Addition of fugitives capture for casting operations;
     Improvement of existing control devices or addition of 
fabric filters; and
     Addition of rooftop ventilation, in which fugitive 
emissions escaping local control are collected in the roof canopy over 
process areas through addition of partitions and hoods, then directed 
through roof vents and ducts to control devices.
    For purposes of the supplemental proposal analysis, we assumed that 
enhanced fugitive capture and control systems and roofline ventilation 
will be installed for all operational furnaces at both facilities and 
for MOR operations at Eramet Marietta. The specific elements of the 
capture and control systems selected for each facility are based on 
information supplied by the facilities incorporating their best 
estimates of the improvements to fugitive emission capture and control 
they would implement to achieve the standards included in the 
supplemental proposal. We estimate the total capital costs of 
installing the required ductwork, fans and control devices under the 
enhanced capture option to be $37.6 million and the total annualized 
cost to be $7.1 million (2012 dollars) for the two plants. We estimate 
that this option would reduce metal HAP emissions by 75 tons, resulting 
in a cost per ton of metal HAP removed to be $94,700 per ton ($47 per 
pound). The total HAP reduction for the enhanced capture option is 
estimated to be 77 tons per year at a cost per ton of $91,900 per ton 
($46 per pound). We also estimate that this option would achieve PM 
emission reductions of 229 tons per year, resulting in cost per ton of 
PM removed of $30,900 per ton and achieve PM2.5 emission 
reductions of 48 tons per year, resulting in a cost per ton of 
PM2.5 removal of $147,000 per ton.

D. What are the economic impacts?

    As a result of the requirements in this supplemental proposal, we 
estimate that the total capital cost for the Eramet facility will be 
about $25 million and the total annualized costs will be about $5.4 
million (in 2012 dollars). For impacts to Felman Production LLC, this 
facility is estimated to incur a total capital cost of $12.4 million 
and a total annualized costs of just under $1.7 million (in 2012 
dollars). In total, these costs could lead to an increase in annualized 
cost of as much as 1.8 percent of sales, which serves as an estimate 
for the increase in product prices, and a decrease in output of as much 
as 9.5 percent. For more information regarding economic impacts, please 
refer to the Economic Impact Analysis report that is included in the 
public docket for this supplemental proposal.

E. What are the benefits?

    The estimated reductions in HAP emissions (i.e., about 77 tpy) that 
would be achieved by this proposal would provide significant benefits 
to public health. For example, there would be a significant reduction 
in emissions of air toxics (especially Mn, Ni, Cd and PAHs). In 
addition to the HAP reductions, we also estimate that this supplemental 
proposal would achieve about 48 tons of reductions in PM2.5 
emissions as a co-benefit of the HAP reductions annually.
    This rulemaking is not an ``economically significant regulatory 
action'' under Executive Order 12866 because it is not likely to have 
an annual effect on the economy of $100 million or more. Therefore, we 
have not conducted a Regulatory Impact Analysis (RIA) for this 
rulemaking or a benefits analysis. While we expect that these avoided 
emissions will result in improvements in air quality and reduce health 
effects associated with exposure to air pollution associated with these 
emissions, we have not quantified or monetized the benefits of reducing 
these emissions for this rulemaking. This does not imply that there are 
no benefits associated with these emission reductions. When determining 
if the benefits of an action exceed its costs, Executive Orders 12866 
and 13563 direct the Agency to consider qualitative benefits that are 
difficult to quantity but nevertheless essential to consider.
    Directly emitted particles are precursors to secondary formation of 
fine particles (PM2.5). Controls installed to reduce HAP 
would also reduce ambient concentrations of PM2.5 as a co-
benefit. Reducing exposure to PM2.5 is

[[Page 60277]]

associated with significant human health benefits, including avoiding 
mortality and morbidity from cardiovascular and respiratory illnesses. 
Researchers have associated PM2.5 exposure with adverse 
health effects in numerous toxicological, clinical and epidemiological 
studies (U.S. EPA, 2009) \57\. When adequate data and resources are 
available and an RIA is required, the EPA generally quantifies several 
health effects associated with exposure to PM2.5 (e.g., U.S. 
EPA, 2012) \58\. These health effects include premature mortality for 
adults and infants, cardiovascular morbidities such as heart attacks, 
hospital admissions and respiratory morbidities such as asthma attacks, 
acute bronchitis, hospital and emergency department visits, work loss 
days, restricted activity days and respiratory symptoms. The scientific 
literature also suggests that exposure to PM2.5 is also 
associated with adverse effects on birth weight, pre-term births, 
pulmonary function and other cardiovascular and respiratory effects 
(U.S. EPA, 2009), but the EPA has not quantified certain outcomes these 
impacts in its benefits analyses. PM2.5 also increases light 
extinction, which is an important aspect of visibility.
---------------------------------------------------------------------------

    \57\ U.S. Environmental Protection Agency (U.S. EPA). 2009. 
Integrated Science Assessment for Particulate Matter (Final Report). 
EPA-600-R-08-139F. National Center for Environmental Assessment--RTP 
Division. Available on the Internet at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=216546.
    \58\ U.S. Environmental Protection Agency (U.S. EPA). 2012. 
Regulatory Impact Analysis for the Proposed Revisions to the 
National Ambient Air Quality Standards for Particulate Matter. 
Office of Air and Radiation, Research Triangle Park, NC. Available 
on the Internet at http://www.epa.gov/ttnecas1/regdata/RIAs/PMRIACombinedFile_Bookmarked.pdf.
---------------------------------------------------------------------------

    The rulemaking is also anticipated to reduce emissions of other 
HAP, including metal HAP (arsenic, cadmium, chromium (both total and 
Cr\+6\), lead compounds, manganese and nickel) and PAHs. Some of these 
HAP are carcinogenic (e.g., arsenic, PAHs) and some have effects other 
than cancer (e.g., kidney disease from cadmium, respiratory and 
immunological effects from nickel). While we cannot quantitatively 
estimate the benefits achieved by reducing emissions of these HAP, we 
would expect benefits by reducing exposures to these HAP. More 
information about the health effects of these HAP can be found on the 
IRIS,\59\ ATSDR,\60\ and California EPA \61\ Web pages.
---------------------------------------------------------------------------

    \59\ US EPA, 2006. Integrated Risk Information System. http://www.epa.gov/iris/index.html.
    \60\ US Agency for Toxic Substances and Disease Registry, 2006. 
Minimum Risk Levels (MRLs) for Hazardous Substances. http://www.atsdr.cdc.gov/mrls/index.html.
    \61\ CA Office of Environmental Health Hazard Assessment, 2005. 
Chronic Reference Exposure Levels Adopted by OEHHA as of December 
2008. http://www.oehha.ca.gov/air/chronic_rels.
---------------------------------------------------------------------------

VI. Request for Comments

    We solicit comments on the revised risk assessment and technology 
review and proposed changes to the previously proposed amendments. We 
seek comments on the additional data received in August 2014 (as 
described in Section II.D above) and the impacts of those new data on 
the analyses and results presented in this notice. We seek comments on 
the sufficiency of the proposed controls for process fugitive 
emissions, the design of such systems and how best to monitor them to 
ensure the systems achieve the estimated efficiency. We also seek 
comments on other aspects of this supplemental proposal, including, but 
not limited to, the proposed opacity standards.
    The EPA is also soliciting comment with regard to expanding the 
monitoring requirements in this NESHAP for fugitive particulate matter 
and manganese emissions being released at the roof vents of furnace 
buildings using one or more of three different options. For the 
following three options the EPA is additionally seeking comment on the 
frequency of monitoring and the cost associated with installation, 
operation, analysis and ongoing reporting. Additional cost information 
of these three monitoring options is included in the Cost Impacts 
document, which is available in the docket.
    First, the EPA is soliciting comment on the potential to require 
the facilities to take periodic measurements of fugitive particulate 
matter and manganese emissions from the roof vents using portable 
filter based measurement technologies. The EPA solicits comment on 
requiring no less than 3 filter based monitoring systems with 
associated anemometers with the goal of quantifying trends in the 
process fugitive emissions that are leaving the furnace buildings. We 
also solicit comment on the appropriate sampling duration and frequency 
of such measurements (e.g., 8-hour samples gathered at each monitor 
several times per week or month). This monitoring could provide useful 
information regarding the remaining fugitive emissions that will be 
escaping the buildings after the facilities install and operate the 
improved capture and controls systems that we expect will be installed 
to comply with this proposed rule. This information will also help 
improve our understanding of the relationship between the process 
fugitive emissions and the specific operations within the furnace 
buildings. However, the measurements would not be tied to a specific 
emissions limit.
    Second, the EPA is soliciting comment on requiring fugitive 
fenceline filter based measurements of particulate matter and manganese 
emissions at the facilities with no less than 3 monitoring systems at 
the property boundaries to monitor trends in ambient concentrations at 
these locations and to use this information (along with meteorological 
data and modeling tools) to attempt to quantify trends in emissions 
that are leaving and entering the facility property. The EPA seeks 
comment on having the monitoring systems use common ambient filter 
based sampling techniques as well as gathering data on meteorological 
conditions simultaneously at each of the sampling sites. The EPA 
recognizes that this monitoring would be capturing both ground level 
and other fugitive emissions from the facilities as well as background 
contributions from other sources, and that this type of monitoring has 
limitations. Nevertheless, EPA is taking comment on the application and 
appropriateness of this type of monitoring as part of the requirements 
within this NESHAP to evaluate emissions leaving the facility property 
and is taking comment on where to position the monitoring systems to 
best evaluate the fugitive emissions.
    Third, the EPA is soliciting comment regarding the use of new 
technologies to provide continuous or near continuous long term 
approaches to monitoring emissions from industrial sources such the 
Ferroalloys production facilities within this source category. To this 
end we are seeking comment on the feasibility and practice associated 
with the use of automated Opacity Monitoring with ASTM D7520-13, using 
digital camera technology (DCOT) at fixed points to interpret visible 
emissions from roof vents associated with the processes at each 
facility, and how this technology could potentially be included as part 
of the requirements in the NESHAP for ferroalloys production sources. 
Specifically we are interested in comments regarding how many fixed 
camera locations would be needed to provide sufficient sun-angle 
viewing during daylight operating hours, and the frequency of the EXIF 
2.1 JPG image analysis (how often the roof vent plume should be 
evaluated).

[[Page 60278]]

    The EPA is moving toward advances in information and emissions 
monitoring technology that is setting the stage for detection, 
processing and communication capabilities that can revolutionize 
environmental protection. The EPA calls this Next Generation 
Compliance. One of the advances in information sharing is increased 
transparency. Using transparency as a way to improve performance and 
increase compliance, the EPA is seeking comments on whether affected 
sources should be required to post Method 9 readings on their company 
Web sites and/or State dashboards.
    Electronic reporting is another next generation tool that saves 
time and money while improving results. The EPA is asking for comments 
on whether the EPA should require affected sources to submit all 
compliance documents such as notice of compliance status form, 
deviations from the process fugitive ventilation plan and outdoor 
fugitive dust plan, and electronic records of the bag leak detection 
system output.
    We are not opening comment on aspects of the 2011 proposal (76 FR 
72508) that have not changed and are not addressed in this supplemental 
proposal. Comments received on the 2011 proposal along with comments 
received on this supplemental proposal will be addressed in the EPA's 
Response to Comment document and final rule preamble for the 
Ferroalloys Production source category.

VII. Submitting Data Corrections

    The site-specific emissions profiles used in the source category 
risk and demographic analyses and instructions are available for 
download on the RTR Web page at: http://www.epa.gov/ttn/atw/rrisk/rtrpg.html. The data files include detailed information for each HAP 
emissions release point for the facilities in the source category.
    If you believe that the data are not representative or are 
inaccurate, please identify the data in question, provide your reason 
for concern and provide any ``improved'' data that you have, if 
available. When you submit data, we request that you provide 
documentation of the basis for the revised values to support your 
suggested changes. To submit comments on the data downloaded from the 
RTR page, complete the following steps:
    1. Within this downloaded file, enter suggested revisions to the 
data fields appropriate for that information.
    2. Fill in the commenter information fields for each suggested 
revision (i.e., commenter name, commenter organization, commenter email 
address, commenter phone number and revision comments).
    3. Gather documentation for any suggested emissions revisions 
(e.g., performance test reports, material balance calculations, etc.).
    4. Send the entire downloaded file with suggested revisions in 
Microsoft[supreg] Access format and all accompanying documentation to 
Docket ID Number EPA-HQ-OAR-*** (through one of the methods described 
in the ADDRESSES section of this preamble).
    5. If you are providing comments on a single facility or multiple 
facilities, you need only submit one file for all facilities. The file 
should contain all suggested changes for all sources at that facility. 
We request that all data revision comments be submitted in the form of 
updated Microsoft[supreg] Excel files that are generated by the 
Microsoft[supreg] Access file. These files are provided on the RTR Web 
page at: http://www.epa.gov/ttn/atw/rrisk/rtrpg.html.

VIII. Statutory and Executive Order Reviews

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

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), this 
action is a significant regulatory action because it raises novel legal 
and policy issues. Accordingly, the EPA submitted this action to the 
Office of Management and Budget (OMB) for review under Executive Orders 
12866 and 13563 (76 FR 3821, January 21, 2011) and any changes made in 
response to OMB recommendations have been documented in the docket for 
this action.

B. Paperwork Reduction Act

    The information collection requirements in this supplemental 
proposed rule have been submitted for approval to the Office of 
Management and Budget (OMB) under the Paperwork Reduction Act, 44 
U.S.C. 3501, et seq. The Information Collection Request (ICR) document 
prepared by the EPA has been assigned EPA ICR number 2448.01.
    We are proposing changes to the paperwork requirements to the 
ferroalloys production source category that were proposed in 2011. In 
the 2011 proposal, we proposed paperwork requirements in the form of 
increased frequency and number of pollutants tested for stack testing 
as described in Sec.  63.1625(c) and tighter parameter monitoring 
requirements to demonstrate continuous compliance as described in Sec.  
63.1625(c)(4) and Sec.  63.1626. We are not proposing changes to these 
requirements. However, in this supplemental proposal we are proposing 
more frequent opacity monitoring requirements compared to the 2011 
proposal and are removing the shop building process fugitives 
monitoring requirements (to demonstrate negative pressure) that we 
proposed in 2011.
    In addition, in the 2011 proposal, we included an estimate of the 
burden associated with the affirmative defense in the ICR. However, as 
explained above, in this supplemental proposal we are withdrawing our 
proposal to include an affirmative defense and the burden estimate has 
been revised accordingly.
    We estimate two regulated entities are currently subject to subpart 
XXX and will be subject to this action. The annual monitoring, 
reporting and recordkeeping burden for this collection (averaged over 
the first 3 years after the effective date of the standards) as a 
result of the supplemental proposal revised amendments to subpart XXX 
(Ferroalloys Production) is estimated to be $643,845 per year. This 
includes 496 labor hours per year at a total labor cost of $44,366 per 
year and total non-labor capital and operation and maintenance costs, 
of $599,479 per year. This estimate includes performance tests, 
notifications, reporting and recordkeeping associated with the new 
requirements for ferroalloys production operations. The total burden 
for the federal government (averaged over the first 3 years after the 
effective date of the standard) is estimated to be 48 hours per year at 
a total labor cost of $2,177 per year. Burden is defined at 5 CFR 
1320.3(b).
    An agency may not conduct or sponsor and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9.
    To comment on the Agency's need for this information, the accuracy 
of the provided burden estimates and any suggested methods for 
minimizing respondent burden, the EPA has established a public docket 
for this rule, which includes this ICR, under Docket ID number Docket 
ID Number EPA-HQ-OAR-2010-0895. Submit any comments related to the ICR 
to the EPA and OMB. See ADDRESSES section at the beginning of this 
notice for where to submit comments to the EPA. Send comments to OMB at 
the Office of Information and Regulatory Affairs, Office of Management 
and Budget, 725 17th Street NW., Washington, DC 20503,

[[Page 60279]]

Attention: Desk Office for the EPA. Since OMB is required to make a 
decision concerning the ICR between 30 and 60 days after October 6, 
2014, a comment to OMB is best assured of having its full effect if OMB 
receives it by November 5, 2014. The final rule will respond to any OMB 
or public comments on the information collection requirements contained 
in this proposal.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements under the Administrative 
Procedure Act, or any other statute, unless the agency certifies that 
the rule will not have a significant economic impact on a substantial 
number of small entities. Small entities include small businesses, 
small organizations and small governmental jurisdictions.
    For purposes of assessing the impacts of this final rule on small 
entities, small entity is defined as: (1) a small business as defined 
by the Small Business Administration's (SBA) regulations at 13 CFR 
121.201; (2) a small governmental jurisdiction that is a government of 
a city, county, town, school district or special district with a 
population of less than 50,000; and (3) a small organization that is 
any not-for-profit enterprise that is independently owned and operated 
and is not dominant in its field. For this source category, which has 
the NAICS code 331110 (i.e., Electrometallurgical ferroalloy product 
manufacturing), the SBA small business size standard is 1,000 employees 
according to the SBA small business standards definitions.
    After considering the economic impacts of today's action on small 
entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. Neither of 
the companies affected by this rule is considered to be a small entity 
per the definition provided in this section.

D. Unfunded Mandates Reform Act

    This action does not contain a federal mandate under the provisions 
of Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), 2 
U.S.C. 1531-1538 for state, local, or tribal governments, or the 
private sector. The action would not result in expenditures of $100 
million or more for state, local and tribal governments, in aggregate, 
or the private sector in any 1 year. This final action imposes no 
enforceable duties on any state, local, or tribal governments, or the 
private sector. Thus, this action is not subject to the requirements of 
sections 202 or 205 of the UMRA.
    This rule is also not subject to the requirements of section 203 of 
UMRA because it contains no regulatory requirements that might 
significantly or uniquely affect small governments as it contains no 
requirements that apply to such governments nor does it impose 
obligations upon them.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government, as 
specified in Executive Order 13132. None of the facilities subject to 
this action are owned or operated by state governments and, because no 
new requirements are being promulgated, nothing in this action will 
supersede state regulations. Thus, Executive Order 13132 does not apply 
to this action.

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

    This action does not have tribal implications, as specified in 
Executive Order 13175 (65 FR 67249, November 9, 2000). Thus, Executive 
Order 13175 does not apply to this action. The EPA specifically 
solicited comment on this action from tribal officials in the 2011 
proposal and none were received during the comment period for that 
proposal.

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

    This action is not subject to Executive Order 13045 (62 FR 19885, 
April 23, 1997) because the Agency does not believe the environmental 
health risks or safety risks addressed by this action present a 
disproportionate risk to children. The report, Analysis of Socio-
Economic Factors for Populations Living Near Ferroalloys Facilities, 
shows that, prior to the implementation of the provisions included in 
the proposal and this supplemental proposal, on a nationwide basis, 
there are approximately 31,000 people exposed to a cancer risk at or 
above 1-in-1 million and approximately 1,500 people exposed to a 
chronic noncancer TOSHI greater than 1 due to emissions from the source 
category. The percentages for all demographic groups, including 
children 18 years and younger, are similar to or lower than their 
respective nationwide percentages. Further, implementation of the 
provisions included in this action is expected to significantly reduce 
the number of at-risk people due to HAP emissions from these sources 
(from up to 31,000 to about 6,600), providing significant benefit to 
all the demographic groups in the at-risk population.
    This rule is expected to reduce environmental impacts for everyone, 
including children. This action establishes emissions limits at the 
levels based on MACT, as required by the CAA. Based on our analysis, we 
believe that this rule does not have a disproportionate impact on 
children.

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

    This action is not a ``significant energy action'' as defined under 
Executive Order 13211, because it is not likely to have a significant 
adverse effect on the supply, distribution or use of energy. This 
action will not create any new requirements that affect the energy 
supply, distribution or use sectors.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Public Law 104-113, 12(d) (15 U.S.C. 272 note) 
directs the EPA to use voluntary consensus standards (VCS) in its 
regulatory activities, unless to do so would be inconsistent with 
applicable law or otherwise impractical. VCS are technical standards 
(e.g., materials specifications, test methods, sampling procedures and 
business practices) that are developed or adopted by VCS bodies. The 
NTTAA directs the EPA to provide Congress, through OMB, explanations 
when the agency decides not to use available and applicable VCS.
    This supplemental proposal involves technical standards. The EPA 
has decided to use EPA Methods 1, 2, 3A, 3B, 4, 5, 5D, 9, 10, 26A, 29, 
30B, 316, CARB 429, SW-846 Method 3052, SW-846 Method 7471b and EPA 
water Method 1631E of 40 CFR Part 60, Appendix A. No applicable VCS 
were identified for EPA Methods 30B, 5D, 316, 1631E and CARB 429, SW-
846 Method 3052 and SW-846 Method 7471b.
    Two VCS were identified acceptable alternatives to the EPA test 
methods for the purposes of this rule. The VCS standard ANSI/ASME PTC 
19-10-1981--Part 10, ``Flue and Exhaust Gas Analyses'' is an acceptable 
alternative to Method 3B. The VCS ASTM D7520-09, ``Standard Test Method 
for Determining the Opacity of a Plume in the Outdoor

[[Page 60280]]

Ambient Atmosphere'' is an acceptable alternative to Method 9 under 
specified conditions. The Agency identified 18 VCS as being potentially 
applicable to these methods cited in this rule. However, the EPA 
determined that the 18 candidate VCS would not be practical due to lack 
of equivalency, documentation, validation data and other important 
technical and policy considerations. The 18 VCS and other information 
and conclusions, including the search and review results, are in the 
docket for this rule.
    Under Sec. Sec.  63.7(f) and 63.8(f) of Subpart A of the General 
Provisions, a source may apply to the EPA for permission to use 
alternative test methods or alternative monitoring requirements in 
place of any required testing methods, performance specifications, or 
procedures in the proposed rule.

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

    Executive Order 12898 (59 FR 7629, February 16, 1994) establishes 
federal executive policy on environmental justice. Its main provision 
directs federal agencies, to the greatest extent practicable and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies and activities on minority populations and low-income 
populations in the United States.
    The EPA has determined that the current health risks posed by 
emissions from this source category are unacceptable. There are up to 
31,000 people nationwide that are currently subject to health risks 
which may not be considered negligible (i.e., cancer risks greater than 
1-in-1 million or chronic noncancer TOSHI greater than 1) due to 
emissions from this source category. The demographic makeup of this 
``at-risk'' population is similar to the national distribution for all 
demographic groups. The proposed supplemental requirements along with 
other proposed requirements (76 FR 72508) will reduce the number of 
people in this at-risk group, from up to 31,000, to about 6,600 people. 
Based on this analysis, the EPA has determined that the proposed 
supplemental requirements will not have disproportionately high and 
adverse human health or environmental effects on minority or low-income 
populations because it increases the level of environmental protection 
for all affected populations.

List of Subjects in 40 CFR Part 63

    Air pollution control, Environmental protection, Hazardous 
substances, Incorporation by reference, Reporting and recordkeeping 
requirements.

    Dated: September 4, 2014.
Gina McCarthy,
Administrator.

    For the reasons stated in the preamble, part 63 of title 40, 
chapter I, of the Code of Federal Regulations is proposed to be amended 
as follows:

PART 63--[AMENDED]

0
1. The authority citation for part 63 continues to read as follows:

    Authority:  42 U.S.C. 7401, et seq.

0
2. Section 63.14 is amended by:
0
a. Adding paragraph (b)(84);
0
b. Revising paragraph (i)(1);
0
c. Revising paragraph (p)(6) and adding paragraphs (p)(21) and (p)(22); 
and
0
d. By adding paragraph (s).

Sec.  63.14  Incorporations by reference.

    (b) * * *
    (84) ASTM D7520-09, ``Standard Test Method for Determining the 
Opacity in a Plume in an Outdoor Ambient Atmosphere,'' IBR approved for 
Sec. Sec.  63.1625(b) and 63.1657(b).
* * * * *
    (i) * * *
    (1) ANSI/ASME PTC 19.10-1981, Flue and Exhaust Gas Analyses [Part 
10, Instruments and Apparatus], issued August 31, 1981 IBR approved for 
Sec. Sec.  63.309(k), 63. 772(e), 63.772(h), 63.865(b), 63.1282(d) and 
(g), 63.1625(b), 63.3166(a), 63.3360(e), 63.3545(a), 63.3555(a), 
63.4166(a), 63.4362(a), 63.4766(a), 63.4965(a), 63.5160(d), 63.9307(c), 
63.9323(a), 63.11148(e), 63.11155(e), 63.11162(f), 63.11163(g), 
63.11410(j), 63.11551(a), 63.11646(a), 63.11945, table 5 to subpart 
DDDDD of this part, table 4 to subpart JJJJJ of this part, Table 5 of 
subpart UUUUU of this part and table 1 to subpart ZZZZZ of this part.
* * * * *
    (p) * * *
    (6) SW-846-7471B, Mercury in Solid Or Semisolid Waste (Manual Cold-
Vapor Technique), Revision 2, February 2007, in EPA Publication No. SW-
846, Test Methods for Evaluating Solid Waste, Physical/Chemical 
Methods, Third Edition, IBR approved for Sec.  63.1625(b), table 6 to 
subpart DDDDD of this part and table 5 to subpart JJJJJJ of this part.
* * * * *
    (21) SW-846-Method 3052, Microwave Assisted Acid Digestion Of 
Siliceous and Organically Based Matrices, Revision 0, December 1996, in 
EPA Publication No. SW-846, Test Methods for Evaluating Solid Waste, 
Physical/Chemical Methods, Third Edition, IBR approved for Sec.  
63.1625(b).
    (22) Method 1631, Revision E: Mercury in Water by Oxidation, Purge 
and Trap and Cold Vapor Atomic Fluorescence Spectrometry, August 2002 
located at: http://water.epa.gov/scitech/methods/cwa/metals/mercury/upload/2007_07_10_methods_method_mercury_1631.pdf, IBR approved for 
Sec.  63.1625(b).
* * * * *
    (s) The following material is available from the California Air 
Resources Board (CARB), 1102 Q Street, Sacramento, California 95814, 
(http://www.arb.ca.gov/testmeth/).
    (1) Method 429, Determination of Polycyclic Aromatic Hydrocarbon 
(PAH) Emissions from Stationary Sources, Adopted September 1989, 
Amended July 1997, IBR approved for Sec.  63.1625(b).
    (2) [Reserved]

Subpart XXX--[Amended]

0
3. Section 63.1620 is added to read as follows:

Sec.  63.1620  Am I subject to this subpart?

    (a) You are subject to this subpart if you own or operate a new or 
existing ferromanganese and/or silicomanganese production facility that 
is a major source or is co-located at a major source of hazardous air 
pollutant emissions.
    (b) You are subject to this subpart if you own or operate any of 
the following equipment as part of a ferromanganese or silicomanganese 
production facility:
    (1) Open, semi-sealed, or sealed submerged arc furnace,
    (2) Casting operations,
    (3) Metal oxygen refining (MOR) process,
    (4) Crushing and screening operations,
    (5) Outdoor fugitive dust sources.
    (c) A new affected source is any of the sources listed in paragraph 
(b) of this section for which construction or reconstruction commenced 
after [DATE OF FINAL RULE PUBLICATION IN THE FEDERAL REGISTER].
    (d) Table 1 of this subpart specifies the provisions of subpart A 
of this part that apply to owners and operators of ferromanganese and 
silicomanganese production facilities subject to this subpart.
    (e) If you are subject to the provisions of this subpart, you are 
also subject to title V permitting requirements under 40 CFR parts 70 
or 71, as applicable.

[[Page 60281]]

    (f) Emission standards in this subpart apply at all times.
0
4. Section 63.1621 is added to read as follows:

Sec.  63.1621  What are my compliance dates?

    (a) Existing affected sources must be in compliance with the 
provisions specified in Sec. Sec.  63.1620 through 63.1629 no later 
than [DATE 2 YEARS AFTER EFFECTIVE DATE OF FINAL RULE].
    (b) Affected sources in existence prior to [DATE OF FINAL RULE 
PUBLICATION IN THE FEDERAL REGISTER] must be in compliance with the 
provisions specified in Sec. Sec.  63.1650 through 63.1661 by November 
21, 2001 and until [DATE 2 YEARS AFTER EFFECTIVE DATE OF FINAL RULE]. 
As of [DATE 2 YEARS AFTER EFFECTIVE DATE OF FINAL RULE], the provisions 
of Sec. Sec.  63.1650 through 63.1661 cease to apply to affected 
sources in existence prior to [DATE OF FINAL RULE PUBLICATION IN THE 
FEDERAL REGISTER]. The provisions of Sec. Sec.  63.1650 through 63.1661 
remain enforceable at a source for its activities prior to [DATE 2 
YEARS AFTER EFFECTIVE DATE OF FINAL RULE].
    (c) If you own or operate a new affected source that commences 
construction or reconstruction after [DATE OF FINAL RULE PUBLICATION IN 
THE FEDERAL REGISTER], you must comply with the requirements of this 
subpart by [DATE OF EFFECTIVE DATE OF FINAL RULE], or upon startup of 
operations, whichever is later.
0
5. Section 63.1622 is added to read as follows:

Sec.  63.1622  What definitions apply to this subpart?

    Terms in this subpart are defined in the Clean Air Act (Act), in 
subpart A of this part, or in this section as follows:
    Bag leak detection system means a system that is capable of 
continuously monitoring particulate matter (dust) loadings in the 
exhaust of a baghouse in order to detect bag leaks and other upset 
conditions. A bag leak detection system includes, but is not limited 
to, an instrument that operates on triboelectric, light scattering, 
light transmittance, or other effect to continuously monitor relative 
particulate matter loadings.
    Capture system means the collection of components used to capture 
the gases and fumes released from one or more emissions points and then 
convey the captured gas stream to a control device or to the 
atmosphere. A capture system may include, but is not limited to, the 
following components as applicable to a given capture system design: 
duct intake devices, hoods, enclosures, ductwork, dampers, manifolds, 
plenums, fans and roofline ventilation systems.
    Casting means the period of time from when molten ferroalloy is 
removed from the tapping station until pouring into casting molds or 
beds is completed. This includes the following operations: pouring 
alloy from one ladle to another, slag separation, slag removal and 
ladle transfer by crane, truck, or other conveyance.
    Crushing and screening equipment means the crushers, grinders, 
mills, screens and conveying systems used to crush, size and prepare 
for packing manganese-containing materials, including raw materials, 
intermediate products and final products.
    Electric arc furnace means any furnace where electrical energy is 
converted to heat energy by transmission of current between electrodes 
partially submerged in the furnace charge.
    Furnace process cycle means the period in which the furnace is 
tapped to the time in which the furnace is tapped again and includes 
periods of charging, smelting, tapping, casting and ladle raking. For 
multiple furnaces operating within a single shop building, furnace 
process cycle means a period sufficient to capture a full cycle of 
charging, smelting, tapping, casting and ladle raking for each furnace 
within the shop building.
    Ladle treatment means a post-tapping process including metal and 
alloy additions where chemistry adjustments are made in the ladle after 
furnace smelting to achieve a specified product.
    Local ventilation means hoods and ductwork designed to capture 
process fugitive emissions close to the area where the emissions are 
generated (e.g., tap hoods).
    Metal oxygen refining (MOR) process means the reduction of the 
carbon content of ferromanganese through the use of oxygen.
    Outdoor fugitive dust source means a stationary source from which 
hazardous air pollutant-bearing particles are discharged to the 
atmosphere due to wind or mechanical inducement such as vehicle 
traffic. Fugitive dust sources include plant roadways, yard areas and 
outdoor material storage and transfer operations.
    Plant roadway means any area at a ferromanganese and 
silicomanganese production facility that is subject to plant mobile 
equipment, such as forklifts, front end loaders, or trucks, carrying 
manganese-bearing materials. Excluded from this definition are employee 
and visitor parking areas, provided they are not subject to traffic by 
plant mobile equipment.
    Process fugitive emissions source means a source of hazardous air 
pollutant emissions that is associated with a ferromanganese or 
silicomanganese production facility and is not a fugitive dust source. 
Process fugitive sources include emissions that escape capture from the 
electric arc furnace, tapping operations, casting operations, ladle 
treatment, MOR or crushing and screening equipment.
    Roofline ventilation system means an exhaust system designed to 
evacuate process fugitive emissions that collect in the roofline area 
to a control device.
    Shop building means the building which houses one or more electric 
arc furnaces or other processes that generate process fugitive 
emissions.
    Shutdown means the cessation of operation of an affected source for 
any purpose.
    Startup means the setting in operation of an affected source for 
any purpose.
    Tapping emissions means the gases and emissions associated with 
removal of product from the electric arc furnace under normal operating 
conditions, such as removal of metal under normal pressure and movement 
by gravity down the spout into the ladle and filling the ladle.
    Tapping period means the time from when a tap hole is opened until 
the time a tap hole is closed.
0
6. Section 63.1623 is added to read as follows:

Sec.  63.1623  What are the emissions standards for new, reconstructed 
and existing facilities?

    (a) Electric arc furnaces. You must install, operate and maintain 
an effective capture system that collects the emissions from each 
electric arc furnace operation (including charging, melting and tapping 
operations and emissions from any vent stacks) and conveys the 
collected emissions to a control device for the removal of the 
pollutants specified in the emissions standards specified in paragraphs 
(a)(1) through (a)(5) of this section.
    (1) Particulate matter emissions. (i) You must not discharge 
exhaust gases from each electric arc furnace operation containing 
particulate matter in excess of 4.0 milligrams per dry standard cubic 
meter (mg/dscm) into the atmosphere from any new or reconstructed 
electric arc furnace.
    (ii) You must not discharge exhaust gases from each electric arc 
furnace operation containing particulate matter in excess of 25 mg/dscm 
into the atmosphere from any existing electric arc furnace.
    (2) Mercury emissions. (i) You must not discharge exhaust gases 
from each

[[Page 60282]]

electric arc furnace operation containing mercury emissions in excess 
of 17 [micro]g/dscm into the atmosphere from any new or reconstructed 
electric arc furnace when producing ferromanganese.
    (ii) You must not discharge exhaust gases from each electric arc 
furnace operation containing mercury emissions in excess of 170 
[micro]g/dscm into the atmosphere from any existing electric arc 
furnace when producing ferromanganese.
    (iii) You must not discharge exhaust gases from each electric arc 
furnace operation containing mercury emissions in excess of 4.0 
[micro]g/dscm into the atmosphere from any new or reconstructed 
electric arc furnace when producing silicomanganese.
    (iv) You must not discharge exhaust gases from each electric arc 
furnace operation containing mercury emissions in excess of 12 
[micro]g/dscm into the atmosphere from any existing electric arc 
furnace when producing silicomanganese.
    (3) Polycyclic aromatic hydrocarbon emissions. (i) You must not 
discharge exhaust gases from each electric arc furnace operation 
containing polycyclic aromatic hydrocarbon emissions in excess of 1,400 
[micro]g/dscm into the atmosphere from any existing electric arc 
furnace when producing ferromanganese.
    (ii) You must not discharge exhaust gases from each electric arc 
furnace operation containing polycyclic aromatic hydrocarbon emissions 
in excess of 880 [micro]g/dscm into the atmosphere from any new or 
reconstructed electric arc furnace when producing ferromanganese.
    (iii) You must not discharge exhaust gases from each electric arc 
furnace operation containing polycyclic aromatic hydrocarbon emissions 
in excess of 120 [micro]g/dscm into the atmosphere from any existing 
electric arc furnace when producing silicomanganese.
    (iv) You must not discharge exhaust gases from each electric arc 
furnace operation containing polycyclic aromatic hydrocarbon emissions 
in excess of 72 [micro]g/dscm into the atmosphere from any new or 
reconstructed electric arc furnace when producing silicomanganese.
    (4) Hydrochloric acid emissions. (i) You must not discharge exhaust 
gases from each electric arc furnace operation containing hydrochloric 
acid emissions in excess of 180 [micro]g/dscm into the atmosphere from 
any new or reconstructed electric arc furnace.
    (ii) You must not discharge exhaust gases from each electric arc 
furnace operation containing hydrochloric acid emissions in excess of 
1,100 [micro]g/dscm into the atmosphere from any existing electric arc 
furnace.
    (5) Formaldehyde emissions. You must not discharge exhaust gases 
from each electric arc furnace operation containing formaldehyde 
emissions in excess of 201 [micro]g/dscm into the atmosphere from any 
new, reconstructed or existing electric arc furnace.
    (b) Process fugitive emissions. (1) You must install, operate and 
maintain a capture system that is designed to collect 95 percent or 
more of the emissions from the process fugitive emissions sources and 
convey the collected emissions to a control device that is demonstrated 
to meet the applicable emission limit specified in paragraph (a)(1) of 
this section.
    (2) The determination of 95-percent overall capture must be 
demonstrated as required by Sec.  63.1624(a).
    (3) You must not cause the emissions exiting from a shop building, 
to exceed an average of 8 percent opacity.
    (i) The opacity readings from the shop building must be taken every 
15 seconds during the observed furnace process cycle and the 15 second 
readings averaged to determine if the 8 percent opacity requirement has 
been met.
    (ii) If the average opacity reading from the shop building is 
greater than 8 percent opacity during an observed furnace process 
cycle, an additional two more furnace process cycles must be observed 
within 7 days and the average opacity during the entire observation 
periods must be less than 8 percent opacity.
    (iii) At no time during operation may the average of any two 
consecutive 6-minute blocks be greater than 20 percent opacity.
    (c) Local ventilation emissions. If you operate local ventilation 
to capture tapping, casting, or ladle treatment emissions and direct 
them to a control device other than one associated with the electric 
arc furnace, you must not discharge into the atmosphere any captured 
emissions containing particulate matter in excess of 4.0 mg/dscm.
    (d) MOR process. You must not discharge into the atmosphere from 
any new, reconstructed or existing MOR process exhaust gases containing 
particulate matter in excess of 3.9 mg/dscm.
    (e) Crushing and screening equipment. You must not discharge into 
the atmosphere from any new, reconstructed, or existing piece of 
equipment associated with crushing and screening exhaust gases 
containing particulate matter in excess of 13 mg/dscm.
    (f) At all times, you must operate and maintain any affected 
source, including associated air pollution control equipment and 
monitoring equipment, in a manner consistent with safety and good air 
pollution control practices for minimizing emissions. Determination of 
whether such operation and maintenance procedures are being used will 
be based on information available to the Administrator that may 
include, but is not limited to, monitoring results, review of operation 
and maintenance procedures, review of operation and maintenance records 
and inspection of the source.
0
7. Section 63.1624 is added to read as follows:

Sec.  63.1624  What are the operational and work practice standards for 
new, reconstructed and existing facilities?

    (a) Process fugitive emissions sources. (1) You must prepare and at 
all times operate according to, a process fugitive emissions 
ventilation plan that documents the design and operations to achieve at 
least 95 percent overall capture of process fugitive emissions. The 
plan will be deemed to achieve this level of capture if it consists of 
the following elements:
    (i) Documentation of engineered hoods and secondary fugitive 
capture systems designed according to the most recent, at the time of 
construction, ventilation design principles recommended by the American 
Conference of Governmental Industrial Hygienists (ACGIH). The process 
fugitive emissions capture systems must be designed to achieve 
sufficient air changes to evacuate the collection area frequently 
enough to ensure process fugitive emissions are effectively collected 
by the ventilation system and ducted to the control device(s). Include 
a schematic for each building indicating duct sizes and locations, hood 
sizes and locations, control device types, size and locations and 
exhaust locations. The design plan must address variables that affect 
capture efficiency such as operations that create cross-drafts and 
describe protocol or design characteristics to minimize such events. 
The design plan must identify the key operating parameters and 
measurement locations to ensure proper operation of the system and 
establish monitoring parameter values that reflect effective capture.
    (ii) List of critical maintenance actions and the schedule to 
conduct them.
    (2) You must submit a copy of the process fugitive emissions 
ventilation

[[Page 60283]]

plan to the designated permitting authority on or before the applicable 
compliance date for the affected source as specified in Sec.  63.1621 
in electronic format and whenever an update is made to the plan. The 
requirement for you to operate the facility according to the written 
process fugitives ventilation plan and specifications must be 
incorporated in the operating permit for the facility that is issued by 
the designated permitting authority under part 70 of this chapter.
    (3) You must update the information required in paragraph (a)(1) 
and (a)(2) of this section every 5 years or whenever there is a 
significant change in variables that affect process fugitives 
ventilation design such as the addition of a new process.
    (b) Outdoor fugitive dust sources. (1) You must prepare and at all 
times operate according to, an outdoor fugitive dust control plan that 
describes in detail the measures that will be put in place to control 
outdoor fugitive dust emissions from the individual fugitive dust 
sources at the facility.
    (2) You must submit a copy of the outdoor fugitive dust control 
plan to the designated permitting authority on or before the applicable 
compliance date for the affected source as specified in Sec.  63.1621. 
The requirement for you to operate the facility according to a written 
outdoor fugitive dust control plan must be incorporated in the 
operating permit for the facility that is issued by the designated 
permitting authority under part 70 of this chapter.
    (3) You are permitted to use existing manuals that describe the 
measures in place to control outdoor fugitive dust sources required as 
part of a state implementation plan or other federally enforceable 
requirement for particulate matter to satisfy the requirements of 
paragraph (b)(1) of this section.
0
8. Section 63.1625 is added to read as follows:

Sec.  63.1625  What are the performance test and compliance 
requirements for new, reconstructed and existing facilities?

    (a) Performance testing. (1) All performance tests must be 
conducted according to the requirements in Sec.  63.7 of subpart A.
    (2) Each performance test in paragraphs (c)(1) and (c)(2) must 
consist of three separate and complete runs using the applicable test 
methods.
    (3) Each run must be conducted under conditions that are 
representative of normal process operations.
    (4) Performance tests conducted on air pollution control devices 
serving electric arc furnaces must be conducted such that at least one 
tapping period, or at least 20 minutes of a tapping period, whichever 
is less, is included in at least two of the three runs. The sampling 
time for each run must be at least as long as three times the average 
tapping period of the tested furnace, but no less than 60 minutes.
    (5) You must conduct the performance tests specified in paragraph 
(c) of this section under such conditions as the Administrator 
specifies based on representative performance of the affected source 
for the period being tested. Upon request, you must make available to 
the Administrator such records as may be necessary to determine the 
conditions of performance tests.
    (b) Test methods. The following test methods in appendices of part 
60 or 63 of this chapter or as specified elsewhere must be used to 
determine compliance with the emission standards.
    (1) Method 1 of Appendix A-1 of 40 CFR part 60 to select the 
sampling port location and the number of traverse points.
    (2) Method 2 of Appendix A-1 of 40 CFR part 60 to determine the 
volumetric flow rate of the stack gas.
    (3)(i) Method 3A or 3B of Appendix A-2 of 40 CFR part 60 (with 
integrated bag sampling) to determine the outlet stack and inlet oxygen 
and CO2 content.
    (ii) You must measure CO2 concentrations at both the 
inlet and outlet of the positive pressure fabric filter in conjunction 
with the pollutant sampling in order to determine isokinetic sampling 
rates.
    (iii) As an alternative to EPA Reference Method 3B, ASME PTC-19-10-
1981-Part 10, ``Flue and Exhaust Gas Analyses'' may be used 
(incorporated by reference, see 40 CFR 63.14).
    (4) Method 4 of Appendix A-3 of 40 CFR part 60 to determine the 
moisture content of the stack gas.
    (5)(i) Method 5 of Appendix A-3 of 40 CFR part 60 to determine the 
particulate matter concentration of the stack gas for negative pressure 
baghouses and positive pressure baghouses with stacks.
    (ii) Method 5D of Appendix A-3 of 40 CFR part 60 to determine 
particulate matter concentration and volumetric flow rate of the stack 
gas for positive pressure baghouses without stacks.
    (iii) The sample volume for each run must be a minimum of 4.0 cubic 
meters (141.2 cubic feet). For Method 5 testing only, you may choose to 
collect less than 4.0 cubic meters per run provided that the filterable 
mass collected (e.g., net filter mass plus mass of nozzle, probe and 
filter holder rinses) is equal to or greater than 10 mg. If the total 
mass collected for two of three of the runs is less than 10 mg, you 
must conduct at least one additional test run that produces at least 10 
mg of filterable mass collected (i.e., at a greater sample volume). 
Report the results of all test runs.
    (6) Method 30B of Appendix A-8 of 40 CFR part 60 to measure 
mercury. Apply the minimum sample volume determination procedures as 
per the method.
    (7)(i) Method 26A of Appendix A-8 of 40 CFR part 60 to determine 
outlet stack or inlet hydrochloric acid concentration.
    (ii) Collect a minimum volume of 2 cubic meters.
    (8)(i) Method 316 of Appendix A of 40 CFR part 63 to determine 
outlet stack or inlet formaldehyde.
    (ii) Collect a minimum volume of 1.0 cubic meter.
    (9) Method 9 of Appendix A-4 of 40 CFR part 60 to determine 
opacity. ASTM D7520-09, ``Standard Test Method for Determining the 
Opacity of a Plume in the Outdoor Ambient Atmosphere'' may be used 
(incorporated by reference, see 40 CFR 63.14) with the following 
conditions:
    (i) During the digital camera opacity technique (DCOT) 
certification procedure outlined in Section 9.2 of ASTM D7520-09, you 
or the DCOT vendor must present the plumes in front of various 
backgrounds of color and contrast representing conditions anticipated 
during field use such as blue sky, trees and mixed backgrounds (clouds 
and/or a sparse tree stand).
    (ii) You must also have standard operating procedures in place 
including daily or other frequency quality checks to ensure the 
equipment is within manufacturing specifications as outlined in Section 
8.1 of ASTM D7520-09.
    (iii) You must follow the recordkeeping procedures outlined in 
Sec.  63.10(b)(1) for the DCOT certification, compliance report, data 
sheets and all raw unaltered JPEGs used for opacity and certification 
determination.
    (iv) You or the DCOT vendor must have a minimum of four (4) 
independent technology users apply the software to determine the 
visible opacity of the 300 certification plumes. For each set of 25 
plumes, the user may not exceed 20 percent opacity of any one reading 
and the average error must not exceed 7.5 percent opacity.
    (v) Use of this approved alternative does not provide or imply a 
certification or validation of any vendor's hardware or software. The 
onus to maintain and verify the certification and/or training of the 
DCOT camera, software and operator in accordance with ASTM D7520-09 and 
these requirements is on the

[[Page 60284]]

facility, DCOT operator and DCOT vendor.
    (10) Methods to determine the mercury content of manganese ore 
including a total metals digestion technique, SW-846 Method 3052 and a 
mercury specific analysis method, SW-846 Method 7471b (Cold Vapor AA) 
or Water Method 1631E (Cold Vapor Atomic Fluorescence).
    (11) California Air Resources Board (CARB) Method 429, 
Determination of Polycyclic Aromatic Hydrocarbon (PAH) Emissions from 
Stationary Sources to determine total PAH emissions. The method is 
available from California Resources Board, 1102 Q Street, Sacramento, 
California 95814, (http://www.arb.ca.gov/testmeth/vol3/M_429.pdf).
    (12) The owner or operator may use alternative measurement methods 
approved by the Administrator following the procedures described in 
Sec.  63.7(f) of subpart A.
    (c) Compliance demonstration with the emission standards.
    (1) Initial Performance Test. You must conduct an initial 
performance test for air pollution control devices or vent stacks 
subject to Sec.  63.1623(a), (b)(1) and (c) through (e) to demonstrate 
compliance with the applicable emission standards.
    (2) Periodic Performance Test. (i) You must conduct annual 
particulate matter tests for wet scrubber air pollution control devices 
subject to Sec.  63.1623(a)(1) to demonstrate compliance with the 
applicable emission standards.
    (ii) You must conduct particulate matter tests every five years for 
fabric filter air pollution control devices subject to Sec.  
63.1623(a)(1) to demonstrate compliance with the applicable emission 
standards.
    (iii) You must conduct annual mercury performance tests for wet 
scrubber and fabric filter air pollution control devices or vent stacks 
subject to Sec.  63.1623 (a)(2) to demonstrate compliance with the 
applicable emission standards.
    (iv) You must conduct ongoing performance tests every five years 
for air pollution control devices or vent stacks subject to Sec.  
63.1623(a)(3) through (a)(5), (b)(1) and (c) through (e) to demonstrate 
compliance with the applicable emission standards.
    (3) Compliance is demonstrated for all sources performing emissions 
tests if the average concentration for the three runs comprising the 
performance test does not exceed the standard.
    (4) Operating Limits. You must establish parameter operating limits 
according to paragraphs (c)(4)(i) through (c)(4)(iv) of this section. 
Unless otherwise specified, compliance with each established operating 
limit shall be demonstrated for each 24-hour operating day.
    (i) For a wet particulate matter scrubber, you must establish the 
minimum liquid flow rate and pressure drop as your operating limits 
during the three-run performance test. If you use a wet particulate 
matter scrubber and you conduct separate performance tests for 
particulate matter, you must establish one set of minimum liquid flow 
rate and pressure drop operating limits. If you conduct multiple 
performance tests, you must set the minimum liquid flow rate and 
pressure drop operating limits at the highest minimum hourly average 
values established during the performance tests.
    (ii) For a wet acid gas scrubber, you must establish the minimum 
liquid flow rate and pH, as your operating limits during the three-run 
performance test. If you use a wet acid gas scrubber and you conduct 
separate performance tests for hydrochloric acid, you must establish 
one set of minimum liquid flow rate and pH operating limits. If you 
conduct multiple performance tests, you must set the minimum liquid 
flow rate and pH operating limits at the highest minimum hourly average 
values established during the performance tests.
    (iii) For emission sources with fabric filters that choose to 
demonstrate continuous compliance through bag leak detection systems 
you must install a bag leak detection system according to the 
requirements in Sec.  63.1626(d) and you must set your operating limit 
such that the sum duration of bag leak detection system alarms does not 
exceed 5 percent of the process operating time during a 6-month period.
    (iv) If you choose to demonstrate continuous compliance through a 
particulate matter CEMS, you must determine an operating limit 
(particulate matter concentration in mg/dscm) during performance 
testing for initial particulate matter compliance. The operating limit 
will be the average of the PM filterable results of the three Method 5 
or Method 5D of Appendix A-3 of 40 CFR part 60 performance test runs. 
To determine continuous compliance, the hourly average PM 
concentrations will be averaged on a rolling 30 operating day basis. 
Each 30 operating day average would have to meet the PM operating 
limit.
    (d) Compliance demonstration with shop building opacity standards. 
(1)(i) If you are subject to Sec.  63.1623(b), you must conduct opacity 
observations of the shop building to demonstrate compliance with the 
applicable opacity standards according to Sec.  63.6(h)(5), which 
addresses the conduct of opacity or visible emission observations.
    (ii) You must conduct the opacity observations according to EPA 
Method 9 of 40 CFR part 60, Appendix A-4, for a period that includes at 
least one complete furnace process cycle for each furnace.
    (iii) You must conduct the opacity observations at least once per 
week for each operating furnace.
    (2) You must determine shop building opacity operating parameters 
based on either monitoring data collected during the compliance 
demonstration or established in an engineering assessment.
    (i) If you choose to establish parameters based on the initial 
compliance demonstration, you must simultaneously monitor parameter 
values for one of the following: the capture system fan motor amperes 
and all capture system damper positions, the total volumetric flow rate 
to the air pollution control device and all capture system damper 
positions, or volumetric flow rate through each separately ducted hood 
that comprises the capture system. Subsequently you must monitor these 
parameters according to Sec.  63.1626(h) and ensure they remain within 
10 percent of the value recorded during the compliant opacity readings.
    (ii) If you choose to establish parameters based on an engineering 
assessment, then a design analysis shall include, for example, 
specifications, drawings, schematics and ventilation system diagrams 
prepared by the owner or operator or capture or control system 
manufacturer or vendor that describes the shop building opacity system 
ventilation design based on acceptable engineering texts. The design 
analysis shall address vent stream characteristics and ventilation 
system design operating parameters such as fan amps, damper position, 
flow rate and/or other specified parameters.
    (iii) You may petition the Administrator to reestablish these 
parameter ranges whenever you can demonstrate to the Administrator's 
satisfaction that the electric arc furnace operating conditions upon 
which the parameter ranges were previously established are no longer 
applicable. The values of these parameter ranges determined during the 
most recent demonstration of compliance must be maintained at the 
appropriate level for each applicable period.
    (3) You will demonstrate continuing compliance with the opacity 
standards by following the monitoring requirements specified in Sec.  
63.1626(g) and the reporting and recordkeeping

[[Page 60285]]

requirements specified in Sec.  63.1628(b)(5).
    (e) Compliance demonstration with the operational and work practice 
standards--(1) Process fugitive emissions sources. You will demonstrate 
compliance by developing and maintaining a process fugitives 
ventilation plan, by reporting any deviations from the plan and by 
taking necessary corrective actions to correct deviations or 
deficiencies.
    (2) Outdoor fugitive dust sources. You will demonstrate compliance 
by developing and maintaining an outdoor fugitive dust control plan, by 
reporting any deviations from the plan and by taking necessary 
corrective actions to correct deviations or deficiencies.
    (3) Baghouses equipped with bag leak detection systems. You will 
demonstrate compliance with the bag leak detection system requirements 
by developing analysis and supporting documentation demonstrating 
conformance with EPA guidance and specifications for bag leak detection 
systems in Sec.  60.57c(h).
0
9. Section 63.1626 is added to read as follows:

Sec.  63.1626  What monitoring requirements must I meet?

    (a) Baghouse Monitoring. You must prepare and at all times operate 
according to, a standard operating procedures manual that describes in 
detail procedures for inspection, maintenance and bag leak detection 
and corrective action plans for all baghouses (fabric filters or 
cartridge filters) that are used to control process vents, process 
fugitive, or outdoor fugitive dust emissions from any source subject to 
the emissions standards in Sec.  63.1623.
    (b) You must submit the standard operating procedures manual for 
baghouses required by paragraph (a) of this section to the 
Administrator or delegated authority for review and approval.
    (c) Unless the baghouse is equipped with a bag leak detection 
system, the procedures that you specify in the standard operating 
procedures manual for inspections and routine maintenance must, at a 
minimum, include the requirements of paragraphs (c)(1) and (c)(2) of 
this section.
    (1) You must observe the baghouse outlet on a daily basis for the 
presence of any visible emissions.
    (2) In addition to the daily visible emissions observation, you 
must conduct the following activities:
    (i) Weekly confirmation that dust is being removed from hoppers 
through visual inspection, or equivalent means of ensuring the proper 
functioning of removal mechanisms.
    (ii) Daily check of compressed air supply for pulse-jet baghouses.
    (iii) An appropriate methodology for monitoring cleaning cycles to 
ensure proper operation.
    (iv) Monthly check of bag cleaning mechanisms for proper 
functioning through visual inspection or equivalent means.
    (v) Quarterly visual check of bag tension on reverse air and 
shaker-type baghouses to ensure that the bags are not kinked (kneed or 
bent) or lying on their sides. Such checks are not required for shaker-
type baghouses using self-tensioning (spring loaded) devices.
    (vi) Quarterly confirmation of the physical integrity of the 
baghouse structure through visual inspection of the baghouse interior 
for air leaks.
    (vii) Semiannual inspection of fans for wear, material buildup and 
corrosion through visual inspection, vibration detectors, or equivalent 
means.
    (d) Bag leak detection system. (1) For each baghouse used to 
control emissions from an electric arc furnace, you must install, 
operate and maintain a bag leak detection system according to 
paragraphs (d)(2) through (d)(4) of this section, unless a system 
meeting the requirements of paragraph (q) of this section, for a CEMS 
and continuous emissions rate monitoring system, is installed for 
monitoring the concentration of particulate matter. You may choose to 
install, operate and maintain a bag leak detection system for any other 
baghouse in operation at the facility according to paragraphs (d)(2) 
through (d)(4) of this section.
    (2) The procedures you specified in the standard operating 
procedures manual for baghouse maintenance must include, at a minimum, 
a preventative maintenance schedule that is consistent with the 
baghouse manufacturer's instructions for routine and long-term 
maintenance.
    (3) Each bag leak detection system must meet the specifications and 
requirements in paragraphs (d)(3)(i) through (d)(3)(viii) of this 
section.
    (i) The bag leak detection system must be certified by the 
manufacturer to be capable of detecting PM emissions at concentrations 
of 1.0 milligram per dry standard cubic meter (0.00044 grains per 
actual cubic foot) or less.
    (ii) The bag leak detection system sensor must provide output of 
relative PM loadings.
    (iii) The bag leak detection system must be equipped with an alarm 
system that will alarm when an increase in relative particulate 
loadings is detected over a preset level.
    (iv) You must install and operate the bag leak detection system in 
a manner consistent with the guidance provided in ``Office of Air 
Quality Planning and Standards (OAQPS) Fabric Filter Bag Leak Detection 
Guidance'' EPA-454/R-98-015, September 1997 (incorporated by reference) 
and the manufacturer's written specifications and recommendations for 
installation, operation and adjustment of the system.
    (v) The initial adjustment of the system must, at a minimum, 
consist of establishing the baseline output by adjusting the 
sensitivity (range) and the averaging period of the device and 
establishing the alarm set points and the alarm delay time.
    (vi) Following initial adjustment, you must not adjust the 
sensitivity or range, averaging period, alarm set points, or alarm 
delay time, except as detailed in the approved standard operating 
procedures manual required under paragraph (a) of this section. You 
cannot increase the sensitivity by more than 100 percent or decrease 
the sensitivity by more than 50 percent over a 365-day period unless 
such adjustment follows a complete baghouse inspection that 
demonstrates that the baghouse is in good operating condition.
    (vii) You must install the bag leak detector downstream of the 
baghouse.
    (viii) Where multiple detectors are required, the system's 
instrumentation and alarm may be shared among detectors.
    (4) You must include in the standard operating procedures manual 
required by paragraph (a) of this section a corrective action plan that 
specifies the procedures to be followed in the case of a bag leak 
detection system alarm. The corrective action plan must include, at a 
minimum, the procedures that you will use to determine and record the 
time and cause of the alarm as well as the corrective actions taken to 
minimize emissions as specified in paragraphs (d)(4)(i) and (d)(4)(ii) 
of this section.
    (i) The procedures used to determine the cause of the alarm must be 
initiated within 30 minutes of the alarm.
    (ii) The cause of the alarm must be alleviated by taking the 
necessary corrective action(s) that may include, but not be limited to, 
those listed in paragraphs (d)(4)(i)(A) through (d)(4)(i)(F) of this 
section.
    (A) Inspecting the baghouse for air leaks, torn or broken filter 
elements, or any other malfunction that may cause an increase in 
emissions.
    (B) Sealing off defective bags or filter media.
    (C) Replacing defective bags or filter media, or otherwise 
repairing the control device.
    (D) Sealing off a defective baghouse compartment.

[[Page 60286]]

    (E) Cleaning the bag leak detection system probe, or otherwise 
repairing the bag leak detection system.
    (F) Shutting down the process producing the particulate emissions.
    (e) If you use a wet particulate matter scrubber, you must collect 
the pressure drop and liquid flow rate monitoring system data according 
to Sec.  63.1628, reduce the data to 24-hour block averages and 
maintain the 24-hour average pressure drop and liquid flow-rate at or 
above the operating limits established during the performance test 
according to Sec.  63.1625(c)(4)(i).
    (f) If you use curtains or partitions to prevent process fugitive 
emissions from escaping the area around the process fugitive emission 
source or other parts of the building, you must perform quarterly 
inspections of the physical condition of these curtains or partitions 
to determine if there are any tears or openings.
    (g) Shop building opacity. In order to demonstrate continuous 
compliance with the opacity standards in Sec.  63.1623, you must comply 
with the requirements Sec.  63.1625(d)(1) and one of the monitoring 
options in paragraphs (g)(1) or (g)(2) of this section. The selected 
option must be consistent with that selected during the initial 
performance test described in Sec.  63.1625(d)(2). Alternatively, you 
may use the provisions of Sec.  63.8(f) to request approval to use an 
alternative monitoring method.
    (1) If you choose to establish operating parameters during the 
compliance test as specified in Sec.  63.1625(d)(2)(i), you must meet 
one of the following requirements.
    (i) Check and record the control system fan motor amperes and 
capture system damper positions once per shift.
    (ii) Install, calibrate and maintain a monitoring device that 
continuously records the volumetric flow rate through each separately 
ducted hood.
    (iii) Install, calibrate and maintain a monitoring device that 
continuously records the volumetric flow rate at the inlet of the air 
pollution control device and check and record the capture system damper 
positions once per shift.
    (2) If you choose to establish operating parameters during the 
compliance test as specified in Sec.  63.1625(d)(2)(ii), you must 
monitor the selected parameter(s) on a frequency specified in the 
assessment and according to a method specified in the engineering 
assessment
    (3) All flow rate monitoring devices must meet the following 
requirements:
    (i) Be installed in an appropriate location in the exhaust duct 
such that reproducible flow rate monitoring will result.
    (ii) Have an accuracy 10 percent over its normal 
operating range and be calibrated according to the manufacturer's 
instructions.
    (4) The Administrator may require you to demonstrate the accuracy 
of the monitoring device(s) relative to Methods 1 and 2 of Appendix A-1 
of part 60 of this chapter.
    (5) Failure to maintain the appropriate capture system parameters 
(e.g., fan motor amperes, flow rate and/or damper positions) 
establishes the need to initiate corrective action as soon as 
practicable after the monitoring excursion in order to minimize excess 
emissions.
    (h) Furnace Capture System. You must perform quarterly (once every 
three months) inspections of the furnace fugitive capture system 
equipment to ensure that the hood locations have not been changed or 
obstructed because of contact with cranes or ladles, quarterly 
inspections of the physical condition of hoods and ductwork to the 
control device to determine if there are any openings or leaks in the 
ductwork, quarterly inspections of the hoods and ductwork to determine 
if there are any flow constrictions in ductwork due to dents or 
accumulated dust and quarterly examinations of the operational status 
of flow rate controllers (pressure sensors, dampers, damper switches, 
etc.) to ensure they are operating correctly. Any deficiencies must be 
recorded and proper maintenance and repairs performed.
    (i) Requirements for sources using CMS. If you demonstrate 
compliance with any applicable emissions limit through use of a 
continuous monitoring system (CMS), where a CMS includes a continuous 
parameter monitoring system (CPMS) as well as a continuous emissions 
monitoring system (CEMS), you must develop a site-specific monitoring 
plan and submit this site-specific monitoring plan, if requested, at 
least 60 days before your initial performance evaluation (where 
applicable) of your CMS. Your site-specific monitoring plan must 
address the monitoring system design, data collection and the quality 
assurance and quality control elements outlined in this section and in 
Sec.  63.8(d). You must install, operate and maintain each CMS 
according to the procedures in your approved site-specific monitoring 
plan. Using the process described in Sec.  63.8(f)(4), you may request 
approval of monitoring system quality assurance and quality control 
procedures alternative to those specified in paragraphs (j)(1) through 
(j)(6) of this section in your site-specific monitoring plan.
    (1) The performance criteria and design specifications for the 
monitoring system equipment, including the sample interface, detector 
signal analyzer and data acquisition and calculations;
    (2) Sampling interface location such that the monitoring system 
will provide representative measurements;
    (3) Equipment performance checks, system accuracy audits, or other 
audit procedures;
    (4) Ongoing operation and maintenance procedures in accordance with 
the general requirements of Sec.  63.8(c)(1) and (c)(3);
    (5) Conditions that define a continuous monitoring system that is 
out of control consistent with Sec.  63.8(c)(7)(i) and for responding 
to out of control periods consistent with Sec.  63.8(c)(7)(ii) and 
(c)(8) or Appendix A to this subpart, as applicable; and
    (6) Ongoing recordkeeping and reporting procedures in accordance 
with provisions in Sec.  63.10(c), (e)(1) and (e)(2)(i) and Appendix A 
to this subpart, as applicable.
    (j) If you have an operating limit that requires the use of a CPMS, 
you must install, operate and maintain each continuous parameter 
monitoring system according to the procedures in paragraphs (j)(1) 
through (j)(7) of this section.
    (1) The continuous parameter monitoring system must complete a 
minimum of one cycle of operation for each successive 15-minute period. 
You must have a minimum of four successive cycles of operation to have 
a valid hour of data.
    (2) Except for periods of monitoring system malfunctions, repairs 
associated with monitoring system malfunctions and required monitoring 
system quality assurance or quality control activities (including, as 
applicable, system accuracy audits and required zero and span 
adjustments), you must operate the CMS at all times the affected source 
is operating. A monitoring system malfunction is any sudden, 
infrequent, not reasonably preventable failure of the monitoring system 
to provide valid data. Monitoring system failures that are caused in 
part by poor maintenance or careless operation are not malfunctions. 
You are required to complete monitoring system repairs in response to 
monitoring system malfunctions and to return the monitoring system to 
operation as expeditiously as practicable.
    (3) You may not use data recorded during monitoring system 
malfunctions, repairs associated with monitoring system malfunctions, 
or required

[[Page 60287]]

monitoring system quality assurance or control activities in 
calculations used to report emissions or operating levels. You must use 
all the data collected during all other required data collection 
periods in assessing the operation of the control device and associated 
control system.
    (4) Except for periods of monitoring system malfunctions, repairs 
associated with monitoring system malfunctions and required quality 
monitoring system quality assurance or quality control activities 
(including, as applicable, system accuracy audits and required zero and 
span adjustments), failure to collect required data is a deviation of 
the monitoring requirements.
    (5) You must conduct other CPMS equipment performance checks, 
system accuracy audits, or other audit procedures specified in your 
site-specific monitoring plan at least once every 12 months.
    (6) You must conduct a performance evaluation of each CPMS in 
accordance with your site-specific monitoring plan.
    (7) You must record the results of each inspection, calibration and 
validation check.
    (k) CPMS for measuring gaseous flow. (1) Use a flow sensor with a 
measurement sensitivity of 5 percent of the flow rate or 10 cubic feet 
per minute, whichever is greater,
    (2) Check all mechanical connections for leakage at least every 
month and
    (3) Perform a visual inspection at least every 3 months of all 
components of the flow CPMS for physical and operational integrity and 
all electrical connections for oxidation and galvanic corrosion if your 
flow CPMS is not equipped with a redundant flow sensor.
    (l) CPMS for measuring liquid flow. (1) Use a flow sensor with a 
measurement sensitivity of 2 percent of the flow rate and
    (2) Reduce swirling flow or abnormal velocity distributions due to 
upstream and downstream disturbances.
    (m) CPMS for measuring pressure. (1) Minimize or eliminate 
pulsating pressure, vibration and internal and external corrosion and
    (2) Use a gauge with a minimum tolerance of 1.27 centimeters of 
water or a transducer with a minimum tolerance of 1 percent of the 
pressure range.
    (3) Perform checks at least once each process operating day to 
ensure pressure measurements are not obstructed (e.g., check for 
pressure tap pluggage daily).
    (n) CPMS for measuring pH. (1) Ensure the sample is properly mixed 
and representative of the fluid to be measured.
    (2) Check the pH meter's calibration on at least two points every 
eight hours of process operation.
    (o) Particulate Matter CEMS. If you are using a CEMS to measure 
particulate matter emissions to meet requirements of this subpart, you 
must install, certify, operate and maintain the particulate matter CEMS 
as specified in paragraphs (q)(1) through (q)(4) of this section.
    (1) You must conduct a performance evaluation of the PM CEMS 
according to the applicable requirements of Sec.  60.13 and Performance 
Specification 11 at 40 CFR part 60, Appendix B of this chapter.
    (2) During each PM correlation testing run of the CEMS required by 
Performance Specification 11 at 40 CFR part 60, Appendix B of this 
chapter, PM and oxygen (or carbon dioxide) collect data concurrently 
(or within a 30-to 60-minute period) by both the CEMS and by conducting 
performance tests using Method 5 or 5D at 40 CFR part 60, Appendix A-3 
or Method 17 at 40 CFR part 60, Appendix A-6 of this chapter.
    (3) Perform quarterly accuracy determinations and daily calibration 
drift tests in accordance with Procedure 2 at 40 CFR part 60, Appendix 
F of this chapter. Relative Response Audits must be performed annually 
and Response Correlation Audits must be performed every three years.
    (4) Within 60 days after the date of completing each CEMS relative 
accuracy test audit or performance test conducted to demonstrate 
compliance with this subpart, you must submit the relative accuracy 
test audit data and the results of the performance test in the as 
specified in Sec.  63.1628(e).
0
10. Section 63.1627 is added to read as follows:

Sec.  63.1627  What notification requirements must I meet?

    (a) You must comply with all of the notification requirements of 
Sec.  63.9 of subpart A, General Provisions. Electronic notifications 
are encouraged when possible.
    (b)(1) You must submit the process fugitives ventilation plan 
required under Sec.  63.1624(a), the outdoor fugitive dust control plan 
required under Sec.  63.1624(b), the site-specific monitoring plan for 
CMS required under Sec.  63.1626(i) and the standard operating 
procedures manual for baghouses required under Sec.  63.1626(a) to the 
Administrator or delegated authority along with a notification that you 
are seeking review and approval of these plans and procedures. You must 
submit this notification no later than [DATE 1 YEAR AFTER EFFECTIVE 
DATE OF FINAL RULE]. For sources that commenced construction or 
reconstruction after [DATE OF EFFECTIVE DATE OF FINAL RULE], you must 
submit this notification no later than 180 days before startup of the 
constructed or reconstructed ferromanganese or silicomanganese 
production facility. For an affected source that has received a 
construction permit from the Administrator or delegated authority on or 
before [DATE OF EFFECTIVE DATE OF FINAL RULE], you must submit this 
notification no later than [DATE 1 YEAR AFTER EFFECTIVE DATE OF FINAL 
RULE].
    (2) The plans and procedures documents submitted as required under 
paragraph (b)(1) of this section must be submitted to the Administrator 
in electronic format for review and approval of the initial submittal 
and whenever an update is made to the procedure.
0
11. Section 63.1628 is added to read as follows:

Sec.  63.1628  What recordkeeping and reporting requirements must I 
meet?

    (a) You must comply with all of the recordkeeping and reporting 
requirements specified in Sec.  63.10 of the General Provisions that 
are referenced in Table 1 to this subpart.
    (1) Records must be maintained in a form suitable and readily 
available for expeditious review, according to Sec.  63.10(b)(1). 
However, electronic recordkeeping and reporting is encouraged and 
required for some records and reports.
    (2) Records must be kept on site for at least two years after the 
date of occurrence, measurement, maintenance, corrective action, 
report, or record, according to Sec.  63.10(b)(1).
    (b) You must maintain, for a period of five years, records of the 
information listed in paragraphs (b)(1) through (b)(13) of this 
section.
    (1) Electronic records of the bag leak detection system output.
    (2) An identification of the date and time of all bag leak 
detection system alarms, the time that procedures to determine the 
cause of the alarm were initiated, the cause of the alarm, an 
explanation of the corrective actions taken and the date and time the 
cause of the alarm was corrected.
    (3) All records of inspections and maintenance activities required 
under Sec.  63.1626(a) as part of the practices described in the 
standard operating procedures manual for baghouses required under Sec.  
63.1626(c).
    (4) Electronic records of the pressure drop and water flow rate 
values for wet scrubbers used to control particulate

[[Page 60288]]

matter emissions as required in Sec.  63.1626(e), identification of 
periods when the 1-hour average pressure drop and water flow rate 
values below the established minimum established and an explanation of 
the corrective actions taken.
    (5) Electronic records of the shop building capture system 
monitoring required under Sec.  63.1626(g)(1) and (g)(2), as 
applicable, or identification of periods when the capture system 
parameters were not maintained and an explanation of the corrective 
actions taken.
    (6) Records of the results of quarterly inspections of the furnace 
capture system required under Sec.  63.1626(h).
    (7) Electronic records of the continuous flow monitors or pressure 
monitors required under Sec.  63.1626(j) and (k) and an identification 
of periods when the flow rate or pressure was not maintained as 
required in Sec.  63.1626(e).
    (8) Electronic records of the output of any CEMS installed to 
monitor particulate matter emissions meeting the requirements of Sec.  
63.1626(i)
    (9) Records of the occurrence and duration of each startup and/or 
shutdown.
    (10) Records of the occurrence and duration of each malfunction of 
operation (i.e., process equipment) or the air pollution control 
equipment and monitoring equipment.
    (11) Records that explain the periods when the procedures outlined 
in the process fugitives ventilation plan required under Sec.  
63.1624(a), the fugitives dust control plan required under Sec.  
63.1624(b), the site-specific monitoring plan for CMS required under 
Sec.  63.1626(i) and the standard operating procedures manual for 
baghouses required under Sec.  63.1626(a).
    (c) You must comply with all of the reporting requirements 
specified in Sec.  63.10 of the General Provisions that are referenced 
in Table 1 to this subpart.
    (1) You must submit reports no less frequently than specified under 
Sec.  63.10(e)(3) of the General Provisions.
    (2) Once a source reports a violation of the standard or excess 
emissions, you must follow the reporting format required under Sec.  
63.10(e)(3) until a request to reduce reporting frequency is approved 
by the Administrator.
    (d) In addition to the information required under the applicable 
sections of Sec.  63.10, you must include in the reports required under 
paragraph (c) of this section the information specified in paragraphs 
(d)(1) through (d)(7) of this section.
    (1) Reports that explain the periods when the procedures outlined 
in the process fugitives ventilation plan required under Sec.  
63.1624(a), the fugitives dust control plan required under Sec.  
63.1624(b), the site-specific monitoring plan for CMS required under 
Sec.  63.1626(i) and the standard operating procedures manual for 
baghouses required under Sec.  63.1626(a).
    (2) Reports that identify the periods when the average hourly 
pressure drop or flow rate of venturi scrubbers used to control 
particulate emissions dropped below the levels established in Sec.  
63.1626(e) and an explanation of the corrective actions taken.
    (3) Bag leak detection system. Reports including the following 
information:
    (i) Records of all alarms.
    (ii) Description of the actions taken following each bag leak 
detection system alarm.
    (4) Reports of the shop building capture system monitoring required 
under Sec.  63.1626(g)(1) and (g)(2), as applicable, identification of 
periods when the capture system parameters were not maintained and an 
explanation of the corrective actions taken.
    (5) Reports of the results of quarterly inspections of the furnace 
capture system required under Sec.  63.1626(h).
    (6) Reports of the CPMS required under Sec.  63.1626, an 
identification of periods when the monitored parameters were not 
maintained as required in Sec.  63.1626 and corrective actions taken.
    (7) If a malfunction occurred during the reporting period, the 
report must include the number, duration and a brief description for 
each type of malfunction that occurred during the reporting period and 
caused or may have caused any applicable emissions limitation to be 
exceeded. The report must also include a description of actions taken 
by an owner or operator during a malfunction of an affected source to 
minimize emissions in accordance with Sec.  63.1623(f), including 
actions taken to correct a malfunction.
    (e) Within 60 days after the date of completing each CEMS relative 
accuracy test audit or performance test conducted to demonstrate 
compliance with this subpart, you must submit the relative accuracy 
test audit data and the results of the performance test in the method 
specified by paragraphs (e)(1) through (e)(2) of this section. The 
results of the performance test must contain the information listed in 
paragraph (e)(2) of this section.
    (1)(i) Within 60 days after the date of completing each performance 
test (as defined in Sec.  63.2), you must submit the results of the 
performance tests, including any associated fuel analyses, required by 
this subpart according to the methods specified in paragraphs 
(e)(1)(i)(A) or (e)(1)(i)(B) of this section.
    (A) For data collected using test methods supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the EPA's ERT Web site 
(http://www.epa.gov/ttn/chief/ert/index.html), you must submit the 
results of the performance test to the Compliance and Emissions Data 
Reporting Interface (CEDRI) that is accessed through the EPA's Central 
Data Exchange (CDX) (http://cdx.epa.gov/epa_home.asp), unless the 
Administrator approves another approach. Performance test data must be 
submitted in a file format generated through the use of the EPA's ERT. 
Owners or operators, who claim that some of the information being 
submitted for performance tests is confidential business information 
(CBI), must submit a complete file generated through the use of the 
EPA's ERT, including information claimed to be CBI, on a compact disk, 
flash drive, or other commonly used electronic storage media to the 
EPA. The electronic media must be clearly marked as CBI and mailed to 
U.S. EPA/OAQPS/CORE CBI Office, Attention: WebFIRE Administrator, MD 
C404-02, 4930 Old Page Rd., Durham, NC 27703. The same ERT file with 
the CBI omitted must be submitted to the EPA via CDX as described 
earlier in this paragraph.
    (B) For any performance test conducted using test methods that are 
not supported by the EPA's ERT as listed on the EPA's ERT Web site, the 
owner or operator shall submit the results of the performance test to 
the Administrator at the appropriate address listed in Sec.  63.13.
    (ii) Within 60 days after the date of completing each CEMS 
performance evaluation (as defined in Sec.  63.2), you must submit the 
results of the performance evaluation according to the method specified 
by either paragraph (b)(1) or (b)(2) of this section.
    (A) For data collection of relative accuracy test audit (RATA) 
pollutants that are supported by the EPA's ERT as listed on the EPA's 
ERT Web site, you must submit the results of the performance evaluation 
to the CEDRI that is accessed through the EPA's CDX, unless the 
Administrator approves another approach. Performance evaluation data 
must be submitted in a file format generated through the use of the 
EPA's ERT. If you claim that some of the performance evaluation 
information being transmitted is CBI, you must submit a complete file 
generated through the use of the EPA's ERT, including information 
claimed to be CBI, on a compact disk or other commonly used electronic 
storage media (including, but not limited to,

[[Page 60289]]

flash drives) by registered letter to the EPA. The compact disk shall 
be clearly marked as CBI and mailed to U.S. EPA/OAQPS/CORE CBI Office, 
Attention: WebFIRE Administrator, MD C404-02, 4930 Old Page Rd., 
Durham, NC 27703. The same ERT file with the CBI omitted must be 
submitted to the EPA via CDX as described earlier in this paragraph.
    (B) For any performance evaluations with RATA pollutants that are 
not supported by the EPA's ERT as listed on the EPA's ERT Web site, you 
shall submit the results of the performance evaluation to the 
Administrator at the appropriate address listed in Sec.  63.13.
    (2) The results of a performance test shall include the purpose of 
the test; a brief process description; a complete unit description, 
including a description of feed streams and control devices; sampling 
site description; pollutants measured; description of sampling and 
analysis procedures and any modifications to standard procedures; 
quality assurance procedures; record of operating conditions, including 
operating parameters for which limits are being set, during the test; 
record of preparation of standards; record of calibrations; raw data 
sheets for field sampling; raw data sheets for field and laboratory 
analyses; chain-of-custody documentation; explanation of laboratory 
data qualifiers; example calculations of all applicable stack gas 
parameters, emission rates, percent reduction rates and analytical 
results, as applicable; and any other information required by the test 
method, a relevant standard, or the Administrator.
0
12. Section 63.1629 is added to read as follows:

Sec.  63.1629  Who implements and enforces this subpart?

    (a) This subpart can be implemented and enforced by the U.S. EPA, 
or a delegated authority such as the applicable state, local, or tribal 
agency. If the U.S. EPA Administrator has delegated authority to a 
state, local, or tribal agency, then that agency, in addition to the 
U.S. EPA, has the authority to implement and enforce this subpart. 
Contact the applicable U.S. EPA Regional Office to find out if this 
subpart is delegated to a state, local, or tribal agency.
    (b) In delegating implementation and enforcement authority of this 
subpart to a state, local, or tribal agency under subpart E of this 
part, the authorities contained in paragraph (c) of this section are 
retained by the Administrator of U.S. EPA and cannot be transferred to 
the state, local, or tribal agency.
    (c) The authorities that cannot be delegated to state, local, or 
tribal agencies are as specified in paragraphs (c)(1) through (c)(4) of 
this section.
    (1) Approval of alternatives to requirements in Sec. Sec.  63.1620 
and 63.1621 and 63.1623 and 63.1624.
    (2) Approval of major alternatives to test methods under Sec.  
63.7(e)(2)(ii) and (f), as defined in Sec.  63.90 and as required in 
this subpart.
    (3) Approval of major alternatives to monitoring under Sec.  
63.8(f), as defined in Sec.  63.90 and as required in this subpart.
    (4) Approval of major alternatives to recordkeeping and reporting 
under Sec.  63.10(f), as defined in Sec.  63.90 and as required in this 
subpart.
0
13. Section 63.1650 is amended by:
0
a. Revising paragraph (d);
0
b. Removing and reserving paragraph (e)(1); and
0
c. Revising paragraph (e)(2) to read as follows:

Sec.  63.1650  Applicability and Compliance Dates.

* * * * *
    (d) Table 1 to this subpart specifies the provisions of subpart A 
of this part that apply to owners and operators of ferroalloy 
production facilities subject to this subpart.
    (e) * * *
    (1) [Reserved]
    (2) Each owner or operator of a new or reconstructed affected 
source that commences construction or reconstruction after August 4, 
1998 and before October 6, 2014, must comply with the requirements of 
this subpart by May 20, 1999 or upon startup of operations, whichever 
is later.
    14. Section 63.1652 is amended by adding paragraph (f) to read as 
follows:

Sec.  63.1652  Emission standards.

* * * * *
    (f) At all times, you must operate and maintain any affected 
source, including associated air pollution control equipment and 
monitoring equipment, in a manner consistent with safety and good air 
pollution control practices for minimizing emissions. Determination of 
whether such operation and maintenance procedures are being used will 
be based on information available to the Administrator that may 
include, but is not limited to, monitoring results, review of operation 
and maintenance procedures, review of operation and maintenance records 
and inspection of the source.
0
15. Section 63.1656 is amended by:
0
a. Adding paragraph (a)(6);
0
b. Revising paragraph (b)(7);
0
c. Revising paragraph (e)(1); and
0
d. Removing and reserving paragraph (e)(2)(ii) to read as follows:

Sec.  63.1656  Performance testing, test methods and compliance 
demonstrations.

    (a) * * *
    (6) You must conduct the performance tests specified in paragraph 
(c) of this section under such conditions as the Administrator 
specifies based on representative performance of the affected source 
for the period being tested. Upon request, you must make available to 
the Administrator such records as may be necessary to determine the 
conditions of performance tests.
    (b) * * *
    (7) Method 9 of Appendix A-4 of 40 CFR part 60 to determine 
opacity. ASTM D7520-09, ``Standard Test Method for Determining the 
Opacity of a Plume in the Outdoor Ambient Atmosphere'' may be used 
(incorporated by reference, see 40 CFR 63.14) with the following 
conditions:
    (i) During the digital camera opacity technique (DCOT) 
certification procedure outlined in Section 9.2 of ASTM D7520-09, the 
owner or operator or the DCOT vendor must present the plumes in front 
of various backgrounds of color and contrast representing conditions 
anticipated during field use such as blue sky, trees and mixed 
backgrounds (clouds and/or a sparse tree stand).
    (ii) The owner or operator must also have standard operating 
procedures in place including daily or other frequency quality checks 
to ensure the equipment is within manufacturing specifications as 
outlined in Section 8.1 of ASTM D7520-09.
    (iii) The owner or operator must follow the recordkeeping 
procedures outlined in Sec.  63.10(b)(1) for the DCOT certification, 
compliance report, data sheets and all raw unaltered JPEGs used for 
opacity and certification determination.
    (iv) The owner or operator or the DCOT vendor must have a minimum 
of four (4) independent technology users apply the software to 
determine the visible opacity of the 300 certification plumes. For each 
set of 25 plumes, the user may not exceed 15 percent opacity of any one 
reading and the average error must not exceed 7.5 percent opacity.
    (v) Use of this approved alternative does not provide or imply a 
certification or validation of any vendor's hardware or software. The 
onus to maintain and verify the certification and/or training of the 
DCOT camera, software and operator in accordance with ASTM D7520-09 and 
these requirements is on the facility, DCOT operator and DCOT vendor.
* * * * *

[[Page 60290]]

    (e) * * *
    (1) Fugitive dust sources. Failure to have a fugitive dust control 
plan or failure to report deviations from the plan and take necessary 
corrective action would be a violation of the general duty to ensure 
that fugitive dust sources are operated and maintained in a manner 
consistent with good air pollution control practices for minimizing 
emissions per Sec.  63.1652(f).
    (2) * * *
    (ii) [Reserved]
* * * * *
0
16. Section 63.1657 is amended by:
0
a. Revising paragraph (a)(6);
0
b. Revising paragraph (b)(3); and
0
c. Revising paragraph (c)(7) to read as follows:

Sec.  63.1657  Monitoring requirements.

    (a) * * *
    (6) Failure to monitor or failure to take corrective action under 
the requirements of paragraph (a) of this section would be a violation 
of the general duty to operate in a manner consistent with good air 
pollution control practices that minimizes emissions per Sec.  
63.1652(f).
    (b) * * *
    (3) Failure to monitor or failure to take corrective action under 
the requirements of paragraph (b) of this section would be a violation 
of the general duty to operate in a manner consistent with good air 
pollution control practices that minimizes emissions per Sec.  
63.1652(f).
    (c) * * *
    (7) Failure to monitor or failure to take corrective action under 
the requirements of paragraph (c) of this section would be a violation 
of the general duty to operate in a manner consistent with good air 
pollution control practices that minimizes emissions per Sec.  
63.1652(f).
0
17. Section 63.1659 is amended by revising paragraph (a)(4) to read as 
follows:

Sec.  63.1659  Reporting Requirements.

    (a) * * *
    (4) Reporting malfunctions. If a malfunction occurred during the 
reporting period, the report must include the number, duration and a 
brief description for each type of malfunction which occurred during 
the reporting period and which caused or may have caused any applicable 
emission limitation to be exceeded. The report must also include a 
description of actions taken by an owner or operator during a 
malfunction of an affected source to minimize emissions in accordance 
with Sec.  63.1652(f), including actions taken to correct a 
malfunction.
* * * * *
0
18. Section 63.1660 is amended by:
0
a. Revising paragraphs (a)(2)(i) and (a)(2)(ii); and
0
b. Removing and reserving paragraphs (a)(2)(iv) and (a)(2)(v) to read 
as follows:

Sec.  63.1660  Recordkeeping Requirements.

    (a) * * *
    (2) * * *
    (i) Records of the occurrence and duration of each malfunction of 
operation (i.e., process equipment) or the air pollution control 
equipment and monitoring equipment;
    (ii) Records of actions taken during periods of malfunction to 
minimize emissions in accordance with Sec.  63.1652(f), including 
corrective actions to restore malfunctioning process and air pollution 
control and monitoring equipment to its normal or usual manner of 
operation;
* * * * *
    (iv) [Reserved]
    (v) [Reserved]
* * * * *
0
19. Add Table 1 to the end of subpart XXX to read as follows:

 Table 1 to Subpart XXX of Part 63--General Provisions Applicability to
                               Subpart XXX
------------------------------------------------------------------------
                               Applies to subpart
          Reference                    XXX                 Comment
------------------------------------------------------------------------
63.1........................  Yes                   ....................
63.2........................  Yes                   ....................
63.3........................  Yes                   ....................
63.4........................  Yes                   ....................
63.5........................  Yes                   ....................
63.6(a), (b), (c)...........  Yes                   ....................
63.6(d).....................  No..................  Section reserved.
63.6(e)(1)(i)...............  No..................  See 63.1623(g) and
                                                     63.1652(f) for
                                                     general duty
                                                     requirement.
63.6(e)(1)(ii)..............  No                    ....................
63.6(e)(1)(iii).............  Yes                   ....................
63.6(e)(2)..................  No..................  Section reserved.
63.6(e)(3)..................  No                    ....................
63.6(f)(1)..................  No                    ....................
6.6(f)(2)-(f)(3)............  Yes                   ....................
63.6(g).....................  Yes                   ....................
63.6(h)(1)..................  No                    ....................
63.6(h)(2)-(h)(9)...........  Yes                   ....................
63.6(i).....................  Yes                   ....................
63.6(j).....................  Yes                   ....................
Sec.   63.7(a)-(d)..........  Yes                   ....................
Sec.   63.7(e)(1)...........  No..................  See 63.1625(a)(5)
                                                     and 63.1656(a)(6)
Sec.   63.7(e)(2)-(e)(4)....  Yes                   ....................
63.7(f), (g), (h)...........  Yes                   ....................
63.8(a)-(b).................  Yes                   ....................
63.8(c)(1)(i)...............  No..................  See 63.1623(g) and
                                                     63.1652(f) for
                                                     general duty
                                                     requirement.
63.8(c)(1)(ii)..............  Yes                   ....................
63.8(c)(1)(iii).............  No                    ....................
63.8(c)(2)-(d)(2)...........  Yes                   ....................
63.8(d)(3)..................  Yes, except for last  SSM plans are not
                               sentence.             required.
63.8(e)-(g).................  Yes                   ....................
63.9(a),(b),(c),(e),(g),(h)(  Yes                   ....................
 1)through (3), (h)(5) and
 (6), (i) and (j).
63.9(f).....................  Yes                   ....................

[[Page 60291]]

 
63.9(h)(4)..................  No                    Reserved
63.10 (a)...................  Yes                   ....................
63.10 (b)(1)................  Yes                   ....................
63.10(b)(2)(i)..............  No                    ....................
63.10(b)(2)(ii).............  No                    See 63.1628 and
                                                     63.1660 for
                                                     recordkeeping of
                                                     (1) occurrence and
                                                     duration and (2)
                                                     actions taken
                                                     during malfunction.
63.10(b)(2)(iii)............  Yes                   ....................
63.10(b)(2)(iv)-(b)(2)(v)...  No                    ....................
63.10(b)(2)(vi)-(b)(2)(xiv).  Yes                   ....................
63.10)(b)(3)................  Yes                   ....................
63.10(c)(1)-(9).............  Yes                   ....................
63.10(c)(10)-(11)...........  No                    See 63.1628 and
                                                     63.1660 for
                                                     malfunction
                                                     recordkeeping
                                                     requirements.
63.10(c)(12)-(c)(14)........  Yes                   ....................
63.10(c)(15)................  No                    ....................
63.10(d)(1)-(4).............  Yes                   ....................
63.10(d)(5).................  No..................  See 63.1628(d)(8)
                                                     and 63.1659(a)(4)
                                                     for malfunction
                                                     reporting
                                                     requirements.
63.10(e)-((f)...............  Yes                   ....................
63.11.......................  No..................  Flares will not be
                                                     used to comply with
                                                     the emission limits
63.12 to 63.15..............  Yes                   ....................
------------------------------------------------------------------------

[FR Doc. 2014-23266 Filed 10-3-14; 8:45 am]
BILLING CODE 6560-50-P