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E.O. 12866 Ferroalloys 2060-AQ11 Proposal 20111006

6560-50-P

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2010-0895; FRL-]

RIN 2060-AQ-11

National Emissions Standards for Hazardous Air Pollutants: 

Ferroalloys Production

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

SUMMARY: The EPA is proposing amendments to the national emissions 

standards for hazardous air pollutants for Ferroalloys Production to 

address the results of the residual risk and technology review that 

the EPA is required to conduct under the Clean Air Act. These 

proposed amendments include revisions to particulate matter standards 

for electric arc furnaces, metal oxygen refining processes, and 

crushing and screening operations. The amendments also add emission 

limits for hydrochloric acid, hydrofluoric acid, mercury, polycyclic 

aromatic hydrocarbons, and formaldehyde from electric arc furnaces. 

Furthermore, Tthe amendments also expand and revise the requirements 

to control fugitive emissions from furnace operations and casting. 

Other proposed requirements related to testing, monitoring, 

notification, recordkeeping, and reporting are included. We are also 

proposing to revise provisions addressing periods of startup, 
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shutdown, and malfunction to ensure that the rules are consistent 

with a recent court decision.

DATES: Comments must be received on or before [INSERT THE DATE 45 

DAYS AFTER THE DATE OF PUBLICATION OF THIS PROPOSED RULE IN THE 

FEDERAL REGISTER]. Under the Paperwork Reduction Act, comments on the 

information collection provisions are best assured of having full 

effect if the Office of Management and Budget (OMB) receives a copy 

of your comments on or before [INSERT THE DATE 30 DAYS AFTER THE DATE 

OF PUBLICATION OF THIS PROPOSED RULE IN THE FEDERAL REGISTER].

Public Hearing. If anyone contacts the EPA requesting to speak 

at a public hearing by [INSERT THE DATE 10 DAYS AFTER THE DATE OF 

PUBLICATION IN THE FEDERAL REGISTER], a public hearing will be held 

on [INSERT THE DATE 15 DAYS AFTER THE DATE OF PUBLICATION IN THE 

FEDERAL REGISTER]. 

ADDRESSES: Submit your comments, identified by Docket ID Number EPAHQ-OAR-2010-0895, by one of the following methods:

http://www.regulations.gov: Follow the on-line instructions for 

submitting comments.

Email: a-and-r-docket@epa.gov, Attention Docket ID Number EPAHQ-OAR-2010-0895.

Fax: (202) 566-9744, Attention Docket ID Number EPA-HQ-OAR-2010-

0895.

Mail: U.S. Postal Service, send comments to: EPA Docket Center, 

EPA West (Air Docket), Attention Docket ID Number EPA-HQ-OAR2010-0895, U.S. Environmental Protection Agency, Mailcode: 

2822T, 1200 Pennsylvania Ave., 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. 
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Hand Delivery: U.S. Environmental Protection Agency, EPA West 

(Air Docket), Room 3334, 1301 Constitution Ave., NW, Washington, 

DC 20004, Attention Docket ID Number 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 Number EPA-HQOAR-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 on-line at http://www.regulations.gov, including any 

personal information provided, unless the comment includes 

information claimed to be confidential business information (CBI) or 

other information whose disclosure is restricted by statute. Do not 

submit information that you consider to be CBI or otherwise protected 

through http://www.regulations.gov or email. The 

http://www.regulations.gov website 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 
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EPA may not be able to consider your comment. Electronic files should 

avoid the use of special characters, 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

epa.gov/epahome/dockets.htm.

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 West, 

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 a public hearing is held, it will begin at 

10:00 a.m. on [INSERT THE DATE 15 DAYS AFTER THE DATE OF PUBLICATION

OF THIS PROPOSED RULE IN THE FEDERAL REGISTER] and will be held at 

the EPA‘s campus in Research Triangle Park, North Carolina, or at an 

alternate facility nearby. Persons interested in presenting oral 
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testimony or inquiring as to whether a public hearing is to be held 

should contact Ms. Virginia Hunt, Office of Air Quality Planning and 

Standards (OAQPS), Sector Policies and Programs Division, (D243-02), 

U.S. Environmental Protection Agency, Research Triangle Park, North 

Carolina 27711; telephone number: (919) 541–0832.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 

action, contact Mr. Conrad Chin, Sector Policies and Programs 

Division (D243-02), Office of Air Quality Planning and Standards, 

U.S. Environmental Protection Agency, Research Triangle Park, North 

Carolina 27711, telephone (919) 541-1512; fax number: (919) 541-3207; 

and email address: chin.conrad@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, North Carolina 27711; telephone number: (919) 

541–2076; fax number: (919) 541–0840; 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 the appropriate person listed in Table 1 

of this preamble.

Table 1. List of EPA Contacts For The NESHAP Addressed In This 

Proposed Action

NESHAP for: OECA Contact1 OAQPS Contact2

Ferroalloys 

Production

Cary Secrest, (202) 

564-8661

secrest.cary@epa.gov 

Conrad Chin, (919) 

541-1512, 

chin.conrad@epa.gov

1 EPA Office of Enforcement and Compliance Assurance.
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2 EPA Office of Air Quality Planning and Standards.

SUPPLEMENTARY INFORMATION:

Preamble Acronyms and Abbreviations

Several acronyms and terms used to describe industrial 

processes, data inventories, and risk modeling are included in this 

preamble. While this may not be an exhaustive list, to ease the 

reading of this preamble and for reference purposes, the following 

terms and acronyms are defined here:

ACI Activated Carbon Injection

ADAF age-dependent adjustment factors

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

BPT benefit-per-ton

CAA Clean Air Act

CalEPA California EPA

CBI Confidential Business Information

CFR Code of Federal Regulations

CIIT Chemical Industry Institute of Toxicology

CO2 carbon dioxide

EJ environmental justice

EPA Environmental Protection Agency

ERPG Emergency Response Planning Guidelines 

ERT Electronic Reporting Tool

FR Federal Register

gr/dscf grains per dry standard cubic foot

HAP hazardous air pollutants

HCl hydrochloric acid

HEM-3 Human Exposure Model, Version 1.1.0

HF hydrofluoric acid

HI Hazard Index

HON hazardous organic national emissions standards for

hazardous air pollutants

HQ Hazard Quotient
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ICR information collection request

IRIS Integrated Risk Information System

kg/hr kilograms per hour

kg/hr/MW kilograms per hour per megawatt

km kilometer

lb/hr pounds per hour

lb/hr/MW pounds per hour per megawatt

lb/yr pounds per year

LML lowest measured level

MACT maximum achievable control technology

MACT Code Code within the National Emissions Inventory used to 

identify processes included in a source category

MDL method detection limit

mg/dscm milligrams per dry standard cubic meter

MIR maximum individual risk

MM millions

MW megawatt

NAC/AEGL 

Committee National Advisory Committee for Acute Exposure Guideline 

Levels for Hazardous Substances 

NAICS North American Industry Classification System

NAS National Academy of Sciences

NATA National Air Toxics Assessment

NESHAP National Emissions Standards for Hazardous Air Pollutants

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 bioaccumulative in the environment 

PM particulate matter

POM polycyclic organic matter

QA quality assurance

RCRA Resource Conservation and Recovery Act

RDL representative detection level

REL reference exposure level

RFA Regulatory Flexibility Act

RfC reference concentration
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RfD reference dose

RIA Regulatory Impact Analysis

RTR residual risk and technology review

SAB Science Advisory Board

SBA Small Business Administration

SOP standard operating procedures

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

μg/m3 microgram per cubic meter

UMRA Unfunded Mandates Reform Act

UPL upper predictive limit

URE unit risk estimate

VCS voluntary consensus standards

WWW world wide web

Organization of this Document. The information in this preamble is 

organized as follows:

I. General Information

A. Summary of Costs and Benefits

B. What are NESHAP?

C. Does this action apply to me?

D. Where can I get a copy of this document and other related 

information?

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

II. Background

A. What is this source category and how did the 1999 MACT standards

regulate its HAP emissions?

B. What data collection activities were conducted to support this 

action?

C. What other relevant background information from previous studies 

on ferroalloys emissions is available?

III. Analyses Performed

A. How did we address unregulated emissions sources?

B. How did we estimate risks posed by the source category?
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C. How did we consider the risk results in making decisions for this 

proposal?

D. How did we perform the technology review?

E. What other issues are we addressing in this proposal?

IV. Analytical Results and Proposed Decisions

A. What are the results of our analyses and proposed decisions 

regarding unregulated pollutants?

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

C. What are our proposed decisions based on risk acceptability and 

ample margin of safety?

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 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?

F. What demographic groups might benefit from this regulation?

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. Summary of Costs and Benefits
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Consistent with the recently issued Executive Order 13563, 

―Improving Regulation and Regulatory Review,‖ we have estimated the 

costs and benefits of the proposed rule. The estimated net benefits 

of the proposed rule at a 3 percent discount rate are $676 to $1706

million or $596 to $1506 million at a 7 percent discount rate. The 

monetized benefits in this analysis are due to PM2.5 co-benefits, as 

HAP benefits are not monetized. Table 2 presents is a summary of the 

results of the analysis.

Table 2. Summary of the Estimated Annual Monetized Benefits, Social 

Costs, and Net Benefits for the Proposed Rule in 2015 (Millions of 

2010$)a

3% Discount Rate 7% Discount Rate

Total Monetized 

Benefitsb

$710 to $1780 $630 to $160

Total Social Costs

c $4.10 $4.13

Net Benefits $676 to $1706 $596 to $1506

Non-monetized Benefits Reduced exposure to Hazardous Air Pollutants

(HAP), including Manganese, polycyclic 

aromatic hydrocarbons (PAH), Chromium, 

Arsenic, Nickel, and Mercury

a All estimates are for implementation year 2015 (the benefit

estimates use 2016 values as an approximation); and are rounded to 

two or three (when more detail is needed) significant figures so 

numbers may not sum across columns. All fine particles are assumed to 

have equivalent health effects, but the benefit-per-ton (BPT)

estimates vary because each ton of precursor reduced has a different 

propensity to become particulate matter (PM) 2.5. These benefits 

incorporate the conversion from precursor emissions to ambient fine 

particles. The BPT estimates are based on recent air quality modeling 

specific to the ferroalloys sector.

b All estimates are for 2016, which we use as an approximation for 

impacts in 2015.

c The compliance costs of the proposal serve as a proxy for the social 

costs. The compliance costs are estimated using a 7% interest rate.

Under the proposed amendments, ferroalloys production facilities 

are expected to incur $11.4 million in capital costs to install new 
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air pollution controls and new or improved continuous monitoring 

systems. We have estimated the annualized costs to be $4.0 million, 

which includes estimated monitoring and testing costs. Section V.C of 

this preamble contains more detail on these estimated cost impacts.

B. What are NESHAP?

1. 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 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) calls for us to promulgate national 

technology-based emission standards for hazardous air pollutants 

(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, 

these technology-based standards must reflect the maximum degree of 

emissions reductions of HAP achievable (after considering cost, 

energy requirements, and nonair quality health and environmental 

impacts) and are commonly referred to as maximum achievable control 

technology (MACT) standards.

MACT standards must require 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 
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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 pollutants, 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 sections 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 floors for 

existing sources can be less stringent than floors for new sources, 

but they cannot be 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
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sources for categories or subcategories with fewer than 30 sources). 

In developing MACT standards, we 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 emissions reductions, any 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 8 years, under CAA section 112(d)(6). In 

conducting this review, the EPA is not obliged to completely 

recalculate the prior MACT determination. NRDC v. EPA, 529 F.3d 1077, 

1084 (D. C. Cir., 2008). 

The second stage in standard-setting focuses on reducing any 

remaining (i.e., ―residual‖) risk according to CAA section 112(f). 

This provision requires, first, 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 this report (Residual 

Risk Report to Congress, EPA–453/R–99–001) in March 1999. Congress 

did not act in response to the report, thereby triggering the EPA‘s 
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obligation under CAA section 112(f)(2) to analyze and address 

residual risk.

CAA section 112(f)(2) requires us to determine for source 

categories subject to certain MACT standards, whether those emissions

standards provide an ample margin of safety to protect public health. 

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 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,1 but must 

consider cost, energy, safety and other relevant factors in doing so. 

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

two-step process for developing standards to address any residual 

 

1 ―Adverse environmental effect‖ is defined in CAA section 112(a)(7) 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.
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risk and our 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 Federal Register (FR)

38044, September 14, 1989). The first step in this process is the 

determination of acceptable risk. The second step provides for an 

ample margin of safety to protect public health, which is the level 

at which the standards are to 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).

The terms ―individual most exposed,‖ ―acceptable level‖ and 

―ample margin of safety‖ are not specifically defined in the CAA. 

However, CAA section 112(f)(2)(B) preserves the EPA‘s interpretation 

set out in the Benzene NESHAP, and the United States Court of Appeals 

for the District of Columbia Circuit in NRDC v. EPA, 529 F.3d 1077,

concluded that the EPA‘s interpretation of subsection 112(f)(2) is a 

reasonable one. See NRDC v. EPA, 529 F.3d at 1083 (D.C. Cir. 2008), 

which says ―[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, volume 

1, p. 877 (Senate debate on Conference Report). We also notified 
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Congress in the Residual Risk Report to Congress that we intended to 

use the Benzene NESHAP approach in making CAA section 112(f) residual 

risk determinations (EPA–453/R–99–001, p. ES–11).

In the Benzene NESHAP, we stated as an overall objective:

* * * in protecting public health with an ample margin of 

safety, we strive 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 facility would have if he or she were 

exposed to the maximum pollutant concentrations for 70 years. 

The Agency also stated that, ―The 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.‖ 

The Agency went on to conclude that ―estimated incidence would be 

weighed along with other health risk information in judging 

acceptability.‖ As explained more fully in our Residual Risk Report 

to Congress, the EPA does not define ―rigid line[s] of 

acceptability,‖ but rather considers broad objectives to be weighed 

with a series of other health measures and factors (EPA–453/R–99–001, 

p. ES–11). The determination of what represents an ―acceptable‖ risk 

is based on a judgment of ―what risks are acceptable in the world in 
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which we live‖ (Residual Risk Report to Congress, p. 178, quoting the 

Vinyl Chloride decision at 824 F.2d 1165) 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 38045. 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 acknowledge 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 maximum individual lifetime cancer risk as a metric for 

determining acceptability, we acknowledged in the 1989 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 one million (one 

in 10 thousand) provides a benchmark for judging the acceptability of 
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maximum individual lifetime cancer risk, but does not constitute a 

rigid line for making that determination.

The Agency also explained in the 1989 Benzene NESHAP the 

following: ―In 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-kilometer (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-emissions of 

pollutants.‖ Id.

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 explained in the Benzene NESHAP, 

―[e]ven though the risks judged  ̳acceptable‘ by EPA in the first step 

of the Vinyl Chloride inquiry are already low, 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.‖ 
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In NRDC v. EPA, 529 F.3d 1077, 1082 (D.C. Cir. 2008), the Court 

of Appeals held that section 112(f)(2) ―incorporates EPA‘s 

 ̳interpretation‘ of the Clean Air Act from the Benzene Standard, and 

the text of this provision draws no distinction between carcinogens 

and non-carcinogens.‖ Additionally, the Court held there is nothing 

on the face of the statute that limits the Agency‘s section 112(f) 

assessment of risk to carcinogens. Id. at 1081 – 82. Indeed, in the 

NRDC case, the petitioners argued, among other things, that section 

112(f)(2)(B) applied only to non-carcinogens. The D.C. Circuit flatly 

rejected this position, holding that the text of that provision 

―draws no distinction between carcinogens and non-carcinogens,‖ id., 

and that Congress‘ incorporation of the Benzene standard applies 

equally to carcinogens and non-carcinogens. 

Moreover, the Benzene NESHAP analysis referenced in CAA section 

112(f)(2)(B) is based on EPA‘s interpretation of CAA section 112 as 

it existed prior to the 1990 CAA Amendments. The pre-1990 version of 

section 112 also used the phrase ―ample margin of safety‖ and, in no 

way, distinguished between cancer and non-cancer risks. Inherent in 

determining what is an ―ample margin of safety‖ is determining what 

level of risk is acceptable, which is the first step in a Benzene 

NESHAP analysis. See NRDC v. EPA, 824 F.2d at 1164 (Vinyl Chloride) 

(―We find that the congressional mandate to provide  ̳an ample margin 

of safety‘  ̳to protect the public health‘ requires the Administrator 

to make an initial determination of what is  ̳safe.‘‖). Congress 
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incorporated the same ample margin of safety language in section 

112(f)(2), and as the D.C. Circuit recognized in NRDC, that language 

calls for the Agency to assess both carcinogens and non-carcinogens 

in evaluating whether the MACT standards ―provide an ample margin of 

safety to protect public health.‖ Nothing on the face of the statute 

suggests that in reviewing the risk associated with a source category 

the Agency can ignore non-carcinogens. Such a reading is wholly 

unsustainable and contrary to D.C. Circuit precedent.

When assessing either cancer and noncancer impacts iIn 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. 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 CAA section 112(f). 54 FR 38046.

2. How do we consider the risk results in making decisions?

As discussed in the previous section of this preamble, we apply 

a two-step process for developing standards to address residual risk. 

In the first step, the EPA determines if risks are acceptable. This 

determination ―considers all health information, including risk 

estimation uncertainty, and includes a presumptive limit on maximum 
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individual lifetime [cancer] risk (MIR)2 of approximately one in 10 

thousand [i.e., 100 in one million].‖ 54 FR 38045. In the second step 

of the process, the EPA sets the standard at a level that provides an 

ample margin of safety ―in consideration of all health information, 

including the number of persons at risk levels higher than 

approximately one in one million, as well as other relevant factors, 

including costs and economic impacts, technological feasibility, and 

other factors relevant to each particular decision.‖ Id. 

In past residual risk determinations, the EPA presented a number 

of human health risk metrics associated with emissions from the 

category under review, including: the MIR; the numbers of persons in 

various risk ranges; cancer incidence; the maximum noncancer hazard 

index (HI); and the maximum acute noncancer hazard. In estimating 

risks, the EPA considered sources under review that are located near 

each other and that affect the same population. The EPA developed 

risk estimates based on the actual emissions from the source category 

under review as well as based on the maximum emissions allowed 

pursuant to the source category MACT standard. The EPA also discussed 

and considered risk estimation uncertainties. The EPA is providing 

this same type of information in support of these actions.

The Agency acknowledges that the Benzene NESHAP provides 

flexibility regarding what factors the EPA might consider in making 

our determinations and how they might be weighed for each source 

 

2 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.
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category. In responding to comment on our policy under the Benzene 

NESHAP, the EPA explained that: ―The 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 noncancer 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.‘‖

For example, the level of the MIR is only one factor to be 

weighed in determining acceptability of risks. The Benzene NESHAP 

explains ―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 
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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.‖ 

Similarly, with regard to the ample margin of safety analysis, the 

Benzene NESHAP states 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.‖ 

C. Does this action apply to me?

The regulated industrial source category that is the subject of 

this proposal is listed in Table 3. Table 3 of this preamble is not 

intended to be exhaustive, but rather provides a guide for readers 

regarding the entities likely to be affected by this proposed action. 

The proposed standards, once finalized, will be directly applicable 

to affected sources. Federal, state, local, and tribal government 

entities are not affected by this proposed action. As defined in the 

MACT (major source) source category listing report published by the 

EPA in 1992, the ―Ferroalloys Production‖ source category is any 

facility engaged in producing ferroalloys such as ferrosilicon, 

ferromanganese, and ferrochrome.

3 Subsequently, the EPA redefined the 

MACT source category when it promulgated the Ferroalloy MACT standard 

 

3 EPA. Documentation for Developing the Initial Source Category List – Final 

Report, EPA/OAQPS, EPA-450/3-91-030, July, 1992.
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so that it now includes only major sources that produce products 

containing manganese. (64 FR 27450, May 20, 1999) The MACT standard 

applies specifically to two ferroalloy product types: ferromanganese 

and silicomanganese.

Table 3. NESHAP and Industrial Source Categories Affected By This 

Proposed Action

Source Category NESHAP NAICS 

code1

MACT 

code2

Ferroalloys 

Production

Ferroalloys 

Production

331112 0304

1 North American Industry Classification System

2 Maximum Achievable Control Technology

D. 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 proposal will also be available on the World Wide Web (WWW) 

through the EPA‘s Technology Transfer Network (TTN). Following 

signature by the EPA Administrator, a copy of this proposed action 

will be posted on the TTN‘s policy and guidance page for newly 

proposed or promulgated rules at the following address:

http://www.epa.gov/ttn/atw/rrisk/rtrpg.html. The TTN provides 

information and technology exchange in various areas of air pollution 

control. Supporting documents and other relevant information 

including a version of the regulatory text showing specific proposed 

changes is located in the docket (EPA-HQ-OAR-2010-0895).

Additional information is available on the residual risk and 

technology review (RTR) webpage at:
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http://www.epa.gov/ttn/atw/rrisk/rtrpg.html. This information 

includes source category descriptions and detailed emissions 

estimates and other data that were used as inputs to the risk 

assessment.

E. 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 e-mail. 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, a copy of the comments that does 

not contain the information claimed as CBI must be submitted 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 
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Agency, Research Triangle Park, North Carolina 27711, Attention 

Docket ID Number EPA-HQ-OAR-2010-0895.

II. Background

A. What is this source category and how did the 1999 MACT standards 

regulate its HAP emissions?

The NESHAP (or MACT rule) for Ferroalloys Production: 

Ferromanganese and Silicomanganese was 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. 

The rule‘s product-specific applicability reflected the fact that 

there was only one known major source within the Ferroalloys 

Production source category at the time of promulgation. Since then, 

one other major source of silicomanganese has started production, but 

it was permitted as an existing source.

Today, there are two ferroalloys production facilities subject 

to the MACT rule. No greenfield manganese ferroalloys production 

facilities have been built in over 20 years, and we anticipate no 

greenfield manganese ferroalloys production facilities in the 

foreseeable future, although one facility is currently exploring 

expanding operations through the addition of a new furnace.

 

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.
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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.

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.5 The molten material (product 

and slag) is tapped from the furnace, sometimes subject to postfurnace refining, and poured into casting beds on the furnace room 

floor. Once the material hardens, it is transported to product 

 

5 EPA. AP-42, 12.4. Ferroalloy Production. 10/86.
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crushing and sizing systems and packaged for transport to the 

customer.

HAP generating processes include electrometallurgical (furnace) 

operations (smelting and tapping), other furnace room operations 

(ladle treatment and casting), building fugitives, raw material 

handling and product handling. HAP are emitted from ferroalloys 

production as process emissions, process fugitive emissions, and 

outdoor fugitive dust emissions. 

Process emissions are the exhaust gases from the control 

devices, primarily the furnace control device, metal oxygen refining 

control device and crushing operations control device. The HAP in 

process emissions are primarily composed of metals (mostly manganese, 

arsenic, nickel, lead, mercury and chromium) and also may include 

organic compounds that result from incomplete combustion of coal,

coke or other fuel that is charged to the furnaces as a reducing 

agent. There are also process metal HAP emissions from the product 

crushing control devices. Process fugitive emissions occur at various 

points during the smelting process (such as during charging and 

tapping of furnaces and casting) and are assumed to be similar in 

composition to the process emissions. Outdoor fugitive dust emissions

result from the entrainment of HAP in ambient air due to material 

handling, vehicle traffic, wind erosion from storage piles, and other 

various activities. Outdoor fugitive dust emissions are composed of 

particulate metal HAP only.
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The MACT 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 roadways, yard areas, 

and outdoor material storage and transfer operations. For process 

sources, the NESHAP specifies numerical emissions limits for 

particulate matter (as a surrogate for non-mercury (or particulate) 

metal HAP) from the electric (submerged) arc furnaces (including 

smelting and tapping emissions), with the specific limits depending 

on furnace type, size, and product being made. Particulate matter 

emission limits (again as a surrogate for particulate metal HAP) are 

also in place for process emissions from the metal oxygen refining 

process and product crushing and screening equipment. Table 4 is a 

summary of the applicable limits.
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Table 4. Emission Limits in Subpart XXX

New or 

Reconstructed or 

Existing Source

Affected Source Applicable PM 

Emission Standards

Subpart XXX 

Reference

New or 

reconstructed

Submerged arc furnace 0.23 kilograms per 

hour per megawatt 

(kg/hr/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)

40 CFR 

63.1652(a)(1) 

and (a)(2)

Existing Open submerged arc furnace 

producing ferromanganese and 

operating at a furnace power 

input of 22 megawatts (MW) or 

less

9.8 kg/hr (21.7

lb/hr) 

40 CFR 

63.1652(b)(1)

Existing Open submerged arc furnace 

producing ferromanganese and 

operating at a furnace power 

input greater than 22 MW

13.5 kg/hr (29.8 

lb/hr) 

40 CFR 

63.1652(b)(2)

Existing Open submerged arc furnace 

producing silicomanganese and 

operating at a furnace power 

input greater than 25 MW

16.3 kg/hr (35.9 

lb/hr) 

40 CFR 

63.1652(b)(3)
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New or 

Reconstructed or 

Existing Source

Affected Source Applicable PM 

Emission Standards

Subpart XXX 

Reference

Existing Open submerged arc furnace 

producing silicomanganese and 

operating at a furnace power 

input of 25 MW or less

12.3 kg/hr (27.2 

lb/hr) 

40 CFR 

63.1652(b)(4)

Existing Semi-sealed submerged arc 

furnace (primary, tapping, 

and vent stacks) producing 

ferromanganese

11.2 kg/hr (24.7 

lb/hr) 

40 CFR 

63.1652(c)

New, 

reconstructed, 

or existing

Metal oxygen refining process 69 mg/dscm (0.03 

gr/dscf)

40 CFR 

63.1652(d)

New or 

reconstructed

Individual equipment 

associated with the product 

crushing and screening 

operation

50 mg/dscm (0.022 

gr/dscf)

40 CFR 

63.1652(e)(1)

Existing Individual equipment 

associated with the product 

crushing and screening 

operation

69 mg/dscm (0.03 

gr/dscf)

40 CFR 

63.1652(e)(2)
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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 

§63.1653.

For outdoor fugitive dust sources, as defined in §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. 

B. What data collection activities were conducted to support this 

action?

In April 2010, we issued an information collection request 

(ICR), pursuant to CAA section 114, to the two companies that own and 

operate the two known ferroalloys production facilities producing 
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ferromanganese and silicomanganese. The ICR requested available 

information regarding process equipment, control devices, point and 

fugitive emissions, practices used to control fugitive emissions, and 

other aspects of facility operations. The two companies completed the 

surveys for their facilities and submitted the responses to us in the 

fall of 2010. We also requested that the two facilities conduct 

additional emissions tests in 2010 for certain HAP from specific 

processes that were considered representative of the industry. 

Additional emissions testing was performed for most HAP metals (e.g., 

manganese, arsenic, chromium, lead, nickel and mercury), hydrochloric 

acid (HCl), hydrofluoric acid (HF), formaldehyde, mercury, and PAH. 

The results of these tests were submitted to the EPA in the fall of 

2010 and are available in the docket for this action.

During the development of this regulation we discovered other 

types of ferroalloys production facilities (e.g., non-manganese 

ferroalloy production) that are not subject to this NESHAP. We plan 

to gather additional information on these other types of sources, and 

then evaluate whether we need to establish MACT standards for these 

sources.

C. What other relevant background information from previous studies 

on ferroalloys emissions is available?

In addition to the emissions information and risk assessment 

described in this preamble, other sources of publicly-available data 

exist. Based on historical emissions data from the EPA‘s Toxics 
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Release Inventory, one of the manganese ferroalloys facilities in 

this source category6 has been one of the highest-emitters of 

manganese in the country for at least fifteen years.

(http://www.epa.gov/enviro/facts/tri/index.html). Several agencies 

have conducted studies of the emissions from this facility and 

potential health effects of those emissions.

The Agency for Toxic Substances and Disease Registry (ATSDR), of 

the U.S. Department of Health and Human Services, along with the Ohio 

Department of Health and the Ohio Environmental Protection Agency 

conducted twothree health consultations in the communities 

surrounding this manganese ferroalloys facility between 2004 and 

2007. The investigations found average ambient concentrations of 

manganese at levels higher than background concentrations and higher 

than health benchmark concentrations. More information about these 

studies can be found at 

http://www.atsdr.cdc.gov/sites/washington_marietta/index.html.

As a result of these findings, a health study of chronic adult 

exposure to ambient manganese in the communities surrounding the 

facility was funded by the EPA. . Available results show no 

significant differences in blood manganese concentrations or major 

health outcomes between residents living near a manganese ferroalloy 

facility and residents in a comparison town; however some subtle,

subclinical motor (movement) differences were found in residents in 

 

6 Eramet Marrietta, located in Marietta, Ohio.
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the town with the facility.

7The preliminary results of the health 

study indicate that, within the study population, test results were 

within the average range of the general population, and did not 

indicate a relationship between blood manganese levels and 

neurological test measurements for the study subjects. More 

information about these studies can be found at 

http://www.atsdr.cdc.gov/sites/washington_marietta/index.html.

In addition, uUnder the EPA‘s School Air Toxics Initiative, 

ambient concentrations of manganese were monitored at three schools 

located near the ferroalloys production facility in late 2009. At 

these locations, mean manganese concentrations above the health 

benchmark value were observed. More information about the health 

benchmark value is available in section III.B. More information on 

the School Air Toxics Initiative can be found at 

http://www.epa.gov/schoolair/index/html, while the study including 

the area around this facility can be found at 

http://www.epa.gov/schoolair/pdfs/MariettaTechReport.pdf. The 

monitoring was conducted for the School Air Toxics Initiative; 

however we do present a comparison of modeled concentrations to 

monitored concentrations in the Risk Assessment document, which is 

available in the docket.

III. Analyses Performed

 

7 In press: Kim Y et al. Motor function in adults of an Ohio community with 

environmental manganese exposure. 2011 Neurotoxicology, 

doi:10.1016/j.neuro.2011.07.011.
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In this section, we describe the analyses performed to support 

the proposed decisions for the RTR for this source category.

A. How did we address unregulated emissions sources?

In the course of evaluating the Ferroalloys Production source 

category, we identified certain HAP for which we failed to establish 

emission standards in the original MACT. See National Lime v. EPA, 

233 F. 3d 625, 634 (D.C. Cir. 2000) (EPA has ―clear statutory 

obligation to set emissions standards for each listed HAP‖). 

Specifically, we identified and evaluated emissions standards for 

four HAP (or groups of HAP), described below, that are not 

specifically regulated in the existing 1999 MACT standard, or are 

only regulated for certain emissions points. As described below, for 

these HAP (or groups of HAP), we are proposing emissions limits 

pursuant to section 112(d)(2) and 112(d)(3). The results and proposed 

decisions based on the analyses performed pursuant to CAA section 

112(d)(2) and 112(d)(3) are presented in section IV.A of this 

preamble.

1. Acid Gases (Hydrochloric Acid and Hydrofluoric Acid)

We were unaware of the potential for hydrochloric acid (HCl) or 

HF emissions when we developed the 1999 NESHAP. As a result, we did 

not establish standards for HCl or HF for these sources in the 1999 

NESHAP. We recently received information about HCl and HF HAP

emissions based on emissions data received in response to the ICR., 

and we are now proposing to set emissions limits for HClthese 
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pollutants. Therefore, we are proposing a standard pursuant to 

section 112(d)(2) and (d)(3) (as described further in section IV.A of 

this preamble).

2. Mercury

The 1999 NESHAP specified emissions limits for particulate metal 

HAP (e.g., manganese, arsenic, nickel, chromium) in terms of a 

particulate matter emissions limit (i.e., particulate matter is used 

as a surrogate for metal HAP that are mainly emitted in particulate 

form). There is no explicit standard for mercury, and a significant 

fraction of the mercury emissions are expected to be in gaseous 

mercury forms (e.g., gaseous elemental mercury or gaseous oxidized 

mercury) with a smaller fraction in particulate form. Therefore, we 

are proposing a standard specifically for mercury pursuant to section 

112(d)(2) and (d)(3) (as described further in section IV.A of this 

preamble).

3. Polycyclic Aromatic Hydrocarbons

As described above, the 1999 NESHAP only regulated particulate 

metal HAP emissions and .wWe did not establish standards for PAH. 

Since then, we have determined that electric arc furnaces emit PAH,

emitted from submerged arc furnaces in the 1999 NESHAP. andTherefore,

we are proposing a standard pursuant to section 112(d)(2) and (d)(3)

(as described further in section IV.A of this preamble).

4. Formaldehyde
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As described above, the 1999 NESHAP only regulated particulate 

metal HAP emissions and We did not establish standards for 

formaldehyde. Since then, we have determined that electric arc 

furnaces emit formaldehyde, and emitted from submerged arc furnaces 

in the 1999 NESHAP. we are proposing a standard pursuant to section 

112(d)(2) and (d)(3) (as described further in section IV.A of this 

preamble). Therefore, we are proposing a standard pursuant to section 

112 (as described further in section IV.A of this preamble).

B. How did we estimate risks posed by the source category?

The EPA conducted a risk assessment that provided estimates of 

the MIR posed by the HAP emissions from each source in the source 

category, the 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 provided estimates of the distribution 

of cancer risks within the exposed populations, cancer incidence and 

an evaluation of the potential for adverse environmental effects for 

each source category. The risk assessment consisted of seven primary 

steps, as discussed below. The docket for this rulemaking contains 

the following document which provides more information on the risk 

assessment inputs and models: Draft Residual Risk Assessment for the 

Ferroalloys Production Source Category. The methods used to assess 

risks (as described in the seven primary steps below) are consistent 

with those peer-reviewed by a panel of the EPA‘s Science Advisory 
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Board (SAB) in 2009 and described in their peer review report issued 

in 20108; they are also consistent with the key recommendations 

contained in that report.

1. Establishing the Nature and Magnitude of Actual Emissions and 

Identifying the Emissions Release Characteristics

The two existing ferromanganese and silicomanganese production 

facilities constitute the dataset that is the basis for the risk 

assessment. We estimated the magnitude of emissions using data 

collected through the ICR. In addition to the quality assurance (QA)

of the source data for the facilities contained in the dataset, we 

also checked the coordinates of every emission source in the dataset 

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 QA of 

the emissions data and release characteristics to ensure the data 

were reliable and that there were no outliers.

2. Establishing the Relationship between Actual Emissions and MACTAllowable Emissions Levels

The emissions data in the MACT dataset include estimates of the 

mass of emissions actually emitted during the specified annual time 

period. These ―actual‖ emission levels are often lower than the 

emission levels that a facility might be allowed to emit and still 

comply with the MACT standards. The emissions level allowed to be 

 

8 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.
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emitted by the MACT standards is referred to as the ―MACT-allowable‖ 

emissions level. This represents the highest emissions level that 

could be emitted by facilities without violating the MACT standards.

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 because these risks reflect the 

maximum level sources could emit and still comply with national 

emission standards. But we also explained that it is reasonable to 

consider actual emissions, where such data are available, in both 

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

(54 FR 38044, September 14, 1989.)

For the Ferroalloys Production source category, we evaluated 

allowable stack emissions, based on the level of control required by 

the MACT standards compared to 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: Draft Development of the RTR Emissions Dataset 

for the Ferroalloys Production Source Category, which is available in 

the docket.
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3. Conducting Dispersion Modeling, Determining Inhalation Exposures, 

and Estimating 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 of the primary risk 

assessment activities listed above: (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 km of the modeled sources, and (3) 

estimating individual and population-level inhalation risks using the 

exposure estimates and quantitative dose-response information.

The air dispersion model used by the HEM-3 model (AERMOD) is one 

of the EPA‘s preferred models for assessing pollutant concentrations 

from industrial facilities.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 of 

hourly surface and upper air observations for 189 meteorological 

stations, selected to provide coverage of the United States and 

Puerto Rico. A second library, of United States Census Bureau census 

 

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).
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block10 internal point locations and populations, provides the basis 

of human exposure calculations (Census, 2000). In addition, for each 

census block, the census library includes the elevation and 

controlling hill height, which are also used in dispersion 

calculations. A third library of pollutant unit risk factors and 

other health benchmarks is used to estimate health risks. These risk 

factors and health benchmarks are the latest values recommended by 

the EPA for HAP and other toxic air pollutants. These values are 

available at http://www.epa.gov/ttn/atw/toxsource/summary.html and 

are discussed in more detail later in this section.

In developing the risk assessment for chronic exposures, we used 

the estimated annual average ambient air concentrations of each of 

the 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 (μg/m3)) by its unit risk estimate (URE), 

 

10 A census block is the smallest geographic area for which census statistics are 

tabulated.
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which 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 the 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 doseresponse values in place of, or in addition to, other values, if 

appropriate.

Formaldehyde is a unique case. In 2004, the EPA determined that 

the Chemical Industry Institute of Toxicology (CIIT) cancer doseresponse value for formaldehyde (5.5 x 10-9 per μg/m3) was based on 

better science than the IRIS cancer dose-response value (1.3 x 10-5

per μg/m3), and we switched from using the IRIS value to the CIIT 

value in risk assessments supporting regulatory actions. However,

sSubsequent research published by the EPA suggesteds that the CIIT 

model was not appropriate and, in 2010, the EPA returned to using the 

1991 IRIS value, which is more health protective.11 The EPA has been 

 

11 For details on the justification for this decision, see the memorandum in the 

docket from Peter Preuss to Steve Page entitled, Recommendation for Formaldehyde 

Inhalation Cancer Risk Values, January 22, 2010.
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working on revising the formaldehyde IRIS assessment and the National 

Academy of Sciences (NAS) completed its review of the EPA‘s draft 

assessment in April of 2011 

(http://www.nap.edu/catalog.php?record_id=13142). The EPA will 

followully address all of the NAS Report recommendations and will 

present results obtained by implementing the BBDR model for 

formaldehyde. The EPA will compare these estimates with those 

currently presented in the External Review draft of the assessment 

and will discuss their strengths and weaknesses. As recommended by 

the NAS committee, appropriate sensitivity and uncertainty analyses 

will be an integral component of implementing the biologically based 

dose-response (BBDR) model. on formaldehyde, including those related 

to the CIIT biologically based dose-response model. The draft IRIS 

assessment will be revised in response to the NAS peer review and 

public comments and the final assessment will be posted on the IRIS 

database. May of 2011. The EPA is reviewing the public comments and 

the NAS independent scientific peer review, and the draft IRIS 

assessment will be revised and the final assessment will be posted on 

the IRIS database. In the interim, we will present findings using the 

1991 IRIS value as a primary estimate, and may also consider other 

information as the science evolves.

In the case of nickel compounds, to provide a health 

protectiveconservative estimate of potential cancer risks, we used 

the URE value for nickel subsulfide in this assessment. Based on past 
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scientific and technical considerations, the determination of the 

percent of nickel subsulfide was considered a major factor for 

estimating the extent and magnitude of 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 

the total nickel emissions may be soluble compounds and that the URE 

for the mixture of inhaled nickel compounds (based on nickel 

subsulfide, and representative of pure insoluble crystalline nickel) 

could be derived to reflect the assumption that 65 percent of the 

total mass of nickel may be carcinogenic. Based on more recent, 

consistent views of major scientific bodies (i.e., National 

Toxicology Program in their 12th Report on Carcinogens12, International 

Agency for Research on Cancer13, and other international agencies)14

that now consider all nickel compounds to be carcinogenic, we 

currently consider all nickel compounds to have the potential of 

being as carcinogenic to humansas nickel subsulfide. The major 

scientific bodies mentioned above have also recognized that there are 

differences in toxicity and/or carcinogenic potential across the 

different nickel compounds. More discussion of the nickel URE can be 

 

12 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.

13 International Agency for Research on Cancer (IARD), 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.

14 World Health Organization (WHO, 1991) and the European Union‘s Scientific 

Committee on Health and Environmental Risks (SCHER, 2006).
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found in the risk assessment report in the docket for this action. 

For this analysis, to take a more health-protective approach, we 

considered To implement this approach all nickel compounds as 

carcinogenic as nickel subsulfide in our inhalation risk assessments

and , we have appliedy the IRIS URE for nickel subsulfide without a 

factor to reflect the assumption that 100 percent of the total mass 

of nickel may be as carcinogenic as pure nickel subsulfide. Based on 

the fact that there may be differences in toxicity and/or 

carcinogenic potential across the different nickel compounds, and In 

addition, given that there arehave been two URE values15 derived for 

exposure to mixtures of nickel compounds, as a group, that are 2-3 

fold lower than the IRIS URE for nickel subsulfide, we also consider 

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 a 

plausible range of cancer potency values for different mixtures of 

nickel compounds. 

We also note that polycyclic organic matter (POM) (of which PAH 

are a subset), a carcinogenic HAP with a mutagenic mode of action, is 

emitted by the facilities in this source category.

16

For this compound 

 

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).

16 U.S. EPA. Performing risk assessments that include carcinogens described in the 

Supplemental Guidance as having a mutagenic mode of action. Science Policy Council 

Cancer Guidelines Implementation Work Group Communication II: Memo from W.H. 

Farland, dated October 4, 2005.
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group,

17

the age-dependent adjustment factors (ADAF) described in the 

EPA‘s Supplemental Guidance for Assessing Susceptibility from EarlyLife Exposure to Carcinogens

18

were applied. This adjustment has the 

effect of increasing the estimated lifetime risks for POM by a factor 

of 1.6. In addition, although only a small fraction of the total POM 

emissions were not reported as individual compounds, the EPA 

expresses carcinogenic potency for compounds in this group in terms 

of benzo[a]pyrene equivalence, based on evidence that carcinogenic 

POM has the same mutagenic mechanism of action as benzo[a]pyrene. For 

this reason, the EPA‘s Science Policy Council

19

recommends applying 

the Supplemental Guidance to all carcinogenic PAH for which risk 

estimates are based on relative potency. Accordingly, we have applied 

the ADAF to the benzo[a]pyrene equivalent portion of all POM 

mixtures.

Incremental individual lifetime cancer risks associated with 

emissions from the two facilities in the source category were 

estimated 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 

 

17 See the Risk Assessment for Source Categories document available in the docket 

for a list of HAP with a mutagenic mode of action.

18 U.S. EPA. Supplemental Guidance for Assessing Early-Life Exposure to 

Carcinogens. EPA/630/R-03/003F, 2005. 

http://www.epa.gov/ttn/atw/childrens_supplement_final.pdf.

19 U.S. EPA. Science Policy Council Cancer Guidelines Implementation Workgroup 

Communication II: Memo from W.H. Farland, dated June 14, 2006.
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potential20) emitted by the modeled source. 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 assessment by summing individual risks. A distance of 50 km 

is consistent with both the analysis supporting the 1989 Benzene 

NESHAP (54 FR 38044) and the limitations of Gaussian dispersion 

models, including AERMOD. 

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 either the EPA 

reference concentration (RfC), 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,‖ or, in cases where an RfC 

from the EPA‘s IRIS database is not available, the EPA will utilize 

the following prioritized sources for our chronic dose-response 

values: (1) The Agency for Toxic Substances and Disease Registry 

 

20 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/e

cadv02001.pdf.
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Minimum Risk Level, which is defined as ―an estimate of daily human 

exposure to a substance that is likely to be without an appreciable 

risk of adverse effects (other than cancer) over a specified duration 

of exposure‖; (2) the CalEPA Chronic Reference Exposure Level (REL), 

which is defined as ―the concentration level at or below which no 

adverse health effects are anticipated for a specified exposure 

duration‖; and (3), as noted above, in cases where 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 those doseresponse values in place of or in concert with other values.

Screening estimates of acute exposures and risks were also 

evaluated for each of the HAP at the point of highest off-site 

exposure for each facility (i.e., not just the census block 

centroids), assuming that a person is located at this spot at a time 

when both the peak (hourly) emission rate and worst-case dispersion 

conditions (1991 calendar year data) occur. The acute HQ is the 

estimated acute exposure divided by the acute dose-response value. In 

each case, acute HQ values were calculated 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 
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conservative assumptions for emission 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.‖ Acute REL values are 

based on the most sensitive, relevant, adverse health effect reported 

in the medical and toxicological literature. Acute REL values are 

designed to protect the most sensitive individuals in the population 

by 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.

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/opptintr/aegl/pubs/sop.pdf),21 ―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 

 

21 NAS, 2001. Standing Operating Procedures for Developing Acute Exposure Levels 

for Hazardous Chemicals, page 2.
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Superfund sites.‖ 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.‖ The document lays out the purpose and objectives of AEGL by 

stating (page 21) 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-ina-lifetime, short-term exposures to airborne concentrations of 

acutely toxic, high-priority chemicals.‖ In detailing the intended 

application of AEGL values, the document states (page 31) 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.‖

The AEGL–1 value is then specifically defined as ―the airborne 

concentration 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 
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transient and reversible upon cessation of exposure.‖ The document 

also notes (page 3) 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.‖ 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.‖

ERPG values are derived for use in emergency response, as 

described in the American Industrial Hygiene Association‘s document 

entitled, Emergency Response Planning Guidelines (ERPG) Procedures 

and Responsibilities

(http://www.aiha.org/1documents/committees/ERPSOPs2006.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.‖22 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.‖ 

 

22 ERP Committee Procedures and Responsibilities. November 1, 2006. American 

Industrial Hygiene Association.
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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 1 hour without experiencing or developing 

irreversible or other serious health effects or symptoms which could 

impair an individual‘s ability to take protective action.‖

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, 

higher severity level AEGL–2 or ERPG–2 values are compared 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).
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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 based on process 

knowledge and engineering judgment and with awareness of a Texas 

study of short-term emissions variability, which showed that most 

peak emissions events, in a heavily-industrialized 4-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 9.23 This analysis is 

provided in the Draft Residual Risk Assessment for the Ferroalloys 

Production Source Category, which is available in the docket for this 

action. 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. For the Ferroalloys Production source 

category hourly emissions estimates were available for individual 

 

23 See http://www.tceq.state.tx.us/compliance/field_ops/eer/index.html or docket to 

access the source of these data.
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emissions points, so we did not use the default factor of 10. Using 

emission test data, hourly emission rates were developed for those 

processes considered to operate continuously (i.e., steady-state 

operations for 8,760 hours per year) and for those processes 

considered to operate intermittently (i.e., non-steady-state 

operations for less than 8,760 hours per year). A discussion of the 

hourly emissions estimates is provided in the Methodology for 

Estimation of Maximum Hourly Emissions for Ferroalloy Sources, which 

is available in the docket for this action.. 

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, 

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 using the site-specific facility layout to distinguish 

facility property from an area where the public could be exposed. 

These refinements are discussed in the draft risk assessment 

document, 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 emission rates over a year would 

allow us to perform a probabilistic analysis to estimate potential 
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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. 

However, we recognize that having this level of data is rare, hence 

our use of 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,

24 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 Arrays25 for HAP 

have been developed, we consider additional acute values (i.e., 

occupational and international values) to provide a more complete 

risk characterization.

4. Conducting Multipathway Exposure and Risk ScreeningModeling

The potential for significant human health risks due to 

exposures via routes other than inhalation (i.e., multipathway 

 

24 The SAB peer review of RTR Risk Assessment Methodologies is available at: 

http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File/E

PA-SAB-10-007-unsigned.pdf.

25 U.S. EPA. (2009) Chapter 2.9 Chemical Specific Reference Values for Formaldehyde 

in Graphical Arrays of Chemical-Specific Health Effect Reference Values for 

Inhalation Exposures (Final Report). U.S. Environmental Protection Agency, 

Washington, DC, EPA/600/R-09/061, and available on-line at 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=211003.
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exposures) and the potential for adverse environmental impacts were 

evaluated in a twothree-step process. In the first step, we 

determined whether any facilities emitted any PB-HAP (HAP known to be 

persistent and bio-accumulative in the environment). There are 14 PBHAP compounds or compound classes identified for this screening in 

the EPA‘s Air Toxics Risk Assessment Library (available at 

http://www.epa.gov/ttn/fera/risk_atra_vol1.html). They are cadmium 

compounds, chlordane, chlorinated dibenzodioxins and furans, 

dichlorodiphenyldichloroethylene, heptachlor, hexachlorobenzene, 

hexachlorocyclohexane, lead compounds, mercury compounds, 

methoxychlor, polychlorinated biphenyls, POM, toxaphene and 

trifluralin. 

Because one or more of these PB-HAP are emitted by at least one 

facility in the source category, we proceeded to the second step of 

the evaluation. In this step, we determined whether the facilityspecific emission rates of each of the emitted PB–HAP were large 

enough to create the potential for significant non-inhalation human 

or environmental risks under reasonable worst-case conditions. To 

facilitate this step, we have developed emission rate thresholds for 

each PB–HAP using a hypothetical worst-case 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 hypothetical screening scenario was subjected 

to a sensitivity analysis to ensure that its key design parameters 
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were established such that environmental media concentrations were 

not underestimated (i.e., to minimize the occurrence of false 

negatives or results that suggest that risks might be acceptable 

when, in fact, actual risks are high) and to also minimize the 

occurrence of false positives for human health endpoints. We call 

this application of the TRIM.FaTE model TRIM-Screen. The facilityspecific emission rates of each of the PB–HAP in the source category 

were compared to the TRIM-Screen emission threshold values for each 

of the PB–HAP identified in the source category datasets to assess 

the potential for significant human health risks or environmental 

risks via non-inhalation pathways. 

5. Assessing Risks Considering Emissions Control Options

In addition to assessing baseline inhalation risks and screening 

for potential multipathway risks, we also estimated risks considering 

the potential emissions reductions that would be achieved by the main 

control options under consideration. In these cases, the expected 

emissions reductions were applied to the specific HAP and emissions 

points in the source category dataset to develop corresponding 

estimates of risk reductions. 

6. Conducting Other Risk-Related Analyses: Facilitywide 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 
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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, 

there are no other significant HAP emissions sources operating at 

present. Thus, there was no need to perform a separate facility wide 

risk assessment.

7. Considering Uncertainties in Risk Assessment

Uncertainty and the potential for bias are inherent in all risk 

assessments, including those performed for the source category 

addressed in this proposal. Although uncertainty exists, we believe 

that our approach, which used conservative tools and assumptions, 

ensures that our decisions are health-protective. A brief discussion 

of the uncertainties in the emissions dataset, dispersion modeling, 

inhalation exposure estimates and dose-response relationships follows 

below. A more thorough discussion of these uncertainties is included 

in the risk assessment documentation (Draft Residual Risk Assessment 

for the Ferroalloys Production Source Category) available in the 

docket for this action.

a. Uncertainties in the Emissions Dataset 

Although the development of the RTR 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 were made in estimating 
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emissions values and other factors. The emission estimates considered 

in this analysis generally are annual totals for certain years that 

do not reflect short-term fluctuations during the course of a year or 

variations from year to year. 

The estimates of peak hourly emissions rates from stacks for the 

acute effects screening assessment were based on actual maximum 

hourly emissions estimates for individual emission points, which is

intended to account for emissions fluctuations due to normal facility 

operations.

b. Uncertainties in Dispersion Modeling

While the analysis employed the EPA‘s recommended regulatory 

dispersion model, AERMOD, we recognize that there is uncertainty in 

ambient concentration estimates associated with any model, including 

AERMOD. In circumstances where we had to choose between various model 

options, where possible, model options (e.g., rural/urban, plume 

depletion, chemistry) were selected to provide an overestimate of 

ambient air concentrations of the HAP rather than underestimates. 

However, because of practicality and data limitation reasons, some 

factors (e.g., meteorology, building downwash) have the potential in 

some situations to overestimate or underestimate ambient impacts. For 

example, meteorological data were taken from a single year (1991) and 

facility locations can be a significant distance from the site where 

these data were taken. Despite these uncertainties, we believe that 

at off-site locations and census block centroids, the approach 
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considered in the dispersion modeling analysis should generally yield 

overestimates of ambient HAP concentrations.

c. Uncertainties in Inhalation Exposure

The effects of human mobility on exposures were not included in 

the assessment. Specifically, short-term mobility and long-term 

mobility between census blocks in the modeling domain were not 

considered.

26

The assumption of not considering short or long-term 

population mobility does not bias the estimate of the theoretical 

MIR, 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., one in 10,000 or one in one 

million).

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 overpredict exposures for people in the census block who live farther 

from the facility and under-predict exposures for people in the 

 

26 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.
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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. 

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 emissions 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 United States 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 rare cases, where 

a facility maintains or increases its emissions levels beyond 70 

years, residents live beyond 70 years at the same location, and the 

residents spend most of their days at that location, then the risks 

could potentially be underestimated. Annual cancer incidence 

estimates from exposures to emissions from these sources would not be 

affected by uncertainty in the length of time emissions sources 

operate. 

The exposure estimates used in these analyses assume chronic 

exposures to ambient levels of pollutants. Because most people spend 
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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, these 

levels are typically lower. This factor has the potential to result 

in an overstatement of 25 to 30 percent of exposures.27

In addition to the uncertainties highlighted above, there are 

several factors specific to the acute exposure assessment 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 human activity patterns. In this assessment, we 

assume that individuals remain for 1 hour at the point of maximum 

ambient concentration as determined by the co-occurrence of peak 

emissions and worst-case meteorological conditions. 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 of worst-case impact.

d. Uncertainties in Dose-Response Relationships

There are uncertainties inherent in the development of the doseresponse 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 

 

27 U.S. EPA. National-Scale Air Toxics Assessment for 1996. (EPA 453/R–01–003; 

January 2001; page 85.)
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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 documentation 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 true 

value of a quantity‖ (although this is usually not a true statistical 

confidence limit).28 In some circumstances, the true risk could be as 

low as zero; however, in other circumstances the risk could be 

greater.29 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 

 

28 IRIS glossary (http://www.epa.gov/NCEA/iris/help_gloss.htm).

29 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.
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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). 

Chronic non-cancer reference (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,30 e.g., factors of 10 or 3, used in the absence of compoundspecific data; where data are available, UF may also be developed 

 

30 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.
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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.

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 
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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 peer-reviewed 

reference values for cancer and noncancer effects for all pollutants 

emitted by the sources included in this assessment, some HAP continue 

to have no reference values for cancer or chronic noncancer or acute 

effects. Because exposures to these pollutants cannot be included in 
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a quantitative risk estimate, an understatement of risk for these 

pollutants at environmental exposure levels is possible. For a group 

of compounds that are either unspeciated or do not have reference 

values for every individual compound (e.g., glycol ethers), we 

conservatively use the most protective reference value to estimate 

risk from individual compounds in the group of compounds. 

Additionally, chronic reference values for several of the 

compounds included in this assessment are currently under the EPA 

IRIS review and revised assessments may determine that these 

pollutants are more or less potent than the current value. We may reevaluate residual risks for the final rulemaking if these reviews are 

completed prior to our taking final action for this source category 

and a dose-response metric changes enough to indicate that the risk 

assessment supporting this notice may significantly understate human 

health risk.

e. Uncertainties in the Multipathway and Environmental Effects 

Assessment

We generally assume that when exposure levels are not 

anticipated to adversely affect human health, they also are not 

anticipated to adversely affect the environment. For each source 

category, we generally rely on the site-specific levels of PB-HAP 

emissions to determine whether a full assessment of the multipathway 

and environmental effects is necessary. Our screening methods use 

worst-case scenarios to determine whether multipathway impacts might 
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be important. The results of such a process are biased high for the 

purpose of screening out potential impacts. Thus, when individual 

pollutants or facilities screen out, we are confident that the 

potential for multipathway impacts is negligible. On the other hand, 

when individual pollutants or facilities do not screen out, it does 

not mean that multipollutant impacts are significant, only that we 

cannot rule out that possibility.

C. How did we consider the risk results in making decisions for this 

proposal?

In evaluating and developing standards under section 112(f)(2),

as discussed in section I.B of this preamble, 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)31 of approximately one in 10 thousand 

[i.e., 100 in one million]‖ (54 FR 38045). In the second step of the 

process, the EPA sets the standard at a level that provides an ample 

margin of safety ―in consideration of all health information, 

including the number of persons at risk levels higher than 

approximately one in one million, as well as other relevant factors, 

including costs and economic impacts, technological feasibility, and 

other factors relevant to each particular decision.‖ (Id.)

 

31 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.
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In past residual risk actions, the EPA has presented and 

considered a number of human health risk metrics associated with 

emissions from the category under review, including: the MIR; the 

numbers of persons in various risk ranges; cancer incidence; the 

maximum non-cancer HI; and the maximum acute non-cancer hazard (72 FR 

25138, May 3, 2007; 71 FR 42724, July 27, 2006). In most recent 

proposals (75 FR 65068, October 21, 2010; 75 FR 80220, December 21, 

2010; and 76 FR 29032, May 19, 2011), the EPA also presented and 

considered additional measures of health information, such as 

estimates of the risks associated with the maximum level of emissions 

which might be allowed by the current MACT standards (see, e.g., 75 

FR 65068, October 21, 2010 and 75 FR 80220, December 21, 2010). The 

EPA also discussed and considered risk estimation uncertainties. The 

EPA is providing this same type of information in support of the 

proposed actions described in this Federal Register notice.

The Agency is considering all available health information to 

inform our determinations of risk acceptability and ample margin of

safety under CAA section 112(f). Specifically, 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). Similarly, with regard to making the 

ample margin of safety determination, as stated in the Benzene NESHAP 
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―[in the ample margin decision, 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 Agency acknowledges that the Benzene NESHAP provides

flexibility regarding what factors the EPA might consider in making 

determinations and how these factors might be weighed for each source 

category. In responding to comment on our policy under the Benzene 

NESHAP, the EPA explained that: ―The 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 
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health risk which the Administrator, in [her] judgment, believes are 

appropriate to determining what will  ̳protect the public health‘‖ (54 

FR at 38057).

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).

The EPA wishes to point out that certain health information has 

not been considered to date in making residual risk determinations. 

In assessing risks to populations in the vicinity of the facilities 

in each category, we present estimates of risk associated with HAP 
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emissions from the source category alone (source category risk 

estimates), and generally we have also assessed risks due to HAP 

emissions from the entire facility at which the covered source 

category is located (facilitywide risk estimates). We have not, 

however, attempted to characterize the risks associated with all HAP 

emissions impacting the populations living near the sources in these 

categories. That is, 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. This 

is 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 noncancer 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 
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exposed may be sufficient to result in increased risk of adverse noncancer health effects. In May 2010, the EPA SAB advised us ―... 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.‖32

Although we are interested in placing source category and 

facilitywide 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. At this point, we believe that 

such estimates of total HAP risks will have significantly greater 

associated uncertainties than for the source category or facilitywide 

estimates, and hence would compound the uncertainty in any such 

comparison. This is because we have not conducted a detailed 

technical review of HAP emissions data for source categories and 

facilities that have not previously undergone an RTR review or are 

not currently undergoing such review. We are requesting comment on 

whether and how best to estimate and evaluate total HAP exposure in 

our assessments, and, in particular, on whether and how it might be 

appropriate to use information from the EPA‘s NATA to support such 

estimates. We are also seeking comment on how best to consider 

 

32 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/E

PA-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.
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various types and scales of risk estimates when making our 

acceptability and ample margin of safety determinations under CAA 

section 112(f). 

D. 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 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 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. For the purpose of 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 1999 NESHAP.

Any improvements in add-on control technology or other equipment 

(that were identified and considered during development of the 

1999 NESHAP) that could result in significant additional 

emissions reduction.
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Any work practice or operational procedure that was not 

identified or considered during development of the 1999 NESHAP.

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 1999 NESHAP.

In addition to reviewing the practices, processes, or control 

technologies that were not considered at the time we developed the 

1999 NESHAP, we reviewed a variety of data sources in our evaluation 

of whether there were additional practices, processes, or controls to 

consider for the Ferroalloys Production industry. Among the data 

sources we reviewed were the NESHAP for various industries that were 

promulgated after the 1999 NESHAP. 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 possibly be 

applied to emissions 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 other information sources, such as State or local 

permitting agency databases and industry-supported databases.

E. What other issues are we addressing in this proposal?

In addition to the analyses described above, we also reviewed 

other aspects of the MACT standards for possible revision as 
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appropriate and necessary. Based on this review we have identified 

aspects of the MACT standards that we believe need revision.

This includes proposing revisions to the startup, shutdown, and 

malfunction (SSM) provisions of the MACT rule in order to ensure that 

they are consistent with a recent court decision in Sierra Club v. 

EPA, 551 F. 3d 1019 (D.C. Cir. 2008). In addition, we are proposing 

various other changes to monitoring and testing requirements to 

ensure that this rule includes the measures needed to ensure 

continuous compliance at major sources subject to the revised NESHAP 

for the Ferroalloys Production source category. Our analyses and 

proposed decisions related to SSM and other testing and reporting 

requirements for this source category are presented in section IV.E 

of this preamble."

IV. Analytical Results and Proposed Decisions

This section of the preamble provides the results of our review 

of the MACT rule including the RTR for the Ferroalloys Production 

source category and our proposed decisions concerning changes to the 

1999 NESHAP. 

A. What are the results of our analyses and proposed decisions 

regarding unregulated pollutants?

In this section, we describe how we addressed unregulated 

emissions, including how we calculate MACT floors, and how we 

account for variability in those floor calculations, and how we 

consider beyond the floor options. As described previously, the CAA
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section 112(d) requires the EPA to promulgate national technologybased emission standards for hazardous air pollutants (NESHAP) for 

listed source categories, including this source category. For more 

information on this analysis, see the Draft MACT Floor Analysis for 

the Ferroalloys Production Source Category which is available in the 

docket for this proposed action. Based on the ICR data that we 

collected, we conducted a MACT Floor analysis.

Section 112(d)(3)(B) of the CAA requires that the MACT standards 

for existing sources be at least as stringent as the average 

emissions limitation achieved by the best performing five sources 

(for which the Administrator has or could reasonably obtain emissions 

information) in a category with fewer than 30 sources. The Ferroalloy 

Production source category consists of fewer than 30 sources. Where, 

as here, there are five or fewer sources, we base the MACT floor 

limit on the average emissions limitation achieved by those sources 

for which we have data. 

The EPA must exercise its judgment, based on an evaluation of 

the relevant factors and available data, to determine the level of 

emissions control that has been achieved by the best performing 

sources under variable conditions. It is recognized in the case law 

that the EPA may consider variability in estimating the degree of 

emissions reduction achieved by best-performing sources and in 

setting MACT floors. See Mossville Envt‘l Action Now v. EPA, 370 F.3d 

1232, 1241–42 (D.C. Cir 2004) (holding the EPA may consider emissions 
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variability in estimating performance achieved by best-performing 

sources and may set the floor at a level that a best-performing 

source can expect to meet ―every day and under all operating 

conditions‖).

With regard to data used to determine the MACT limits, Note that 

we received have detailed emissions data for multiple HAP from one 

furnace and one crushing system baghouse at each plant (collected at 

the outlet of the control device) based on an ICR sent to the two 

companies in 2010. We are soliciting additional emissions data for 

the operating furnaces and crushing system baghouses for which we do 

not have data and any other emissions sources at ferroalloys 

production facilities including and available information on the 

quantity and composition of process fugitive emissions. 

1. Mercury Emissions

Section 112(d)(3)(B) of the CAA requires that the MACT standards 

for existing sources be at least as stringent as the average 

emissions limitation achieved by the best performing five sources 

(for which the Administrator has or could reasonably obtain emissions 

information) in a category with fewer than 30 sources. The Ferroalloy 

Production source category consists of fewer than 30 sources. Where, 

as here, there are five or fewer sources, we base the MACT floor

limit on the average emissions limitation achieved by those sources 

for which we have data. 
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The EPA must exercise its judgment, based on an evaluation of 

the relevant factors and available data, to determine the level of 

emissions control that has been achieved by the best performing 

sources under variable conditions. It is recognized in the case law 

that the EPA may consider variability in estimating the degree of 

emissions reduction achieved by best-performing sources and in 

setting MACT floors. See Mossville Envt‘l Action Now v. EPA, 370 F.3d 

1232, 1241–42 (D.C. Cir 2004) (holding the EPA may consider emissions 

variability in estimating performance achieved by best-performing 

sources and may set the floor at a level that a best-performing 

source can expect to meet ―every day and under all operating 

conditions‖).

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 the manganese ore 

although there may be trace amounts in the coke or coal used in the 

smelting process. While some of the mercury that is in particulate or 

oxidized forms is captured by the particulate control devices, the 

more volatile elemental mercury is largely emitted to the atmosphere. 

We found that mercury emissions are emitted from the furnaces as 

measured during the ICR test program (estimated to be 540 pounds per 

year (lb/yr) at one plant and 140 lb/yr at the other plant). 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.
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As discussed above, the MACT floor limit is calculated based on 

the average performance of the units in each category plus an amount 

to account for these units‘ variability. 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 limit. For more information on 

how we calculated the MACT floors and other emission limits, see the 

Ferroalloys Production MACT Floor Analysis document, which is 

available in the docket.

Using this method, the MACT floor (or 99 percent UPL) for 

exhaust mercury concentrations from existing furnaces is 80 μg/dscm 

at 2 percent carbon dioxide (CO2). This MACT floor limit is higher 

than the actual emissions measured during the ICR performance tests 

at each plant. Therefore, we anticipate that both of the existing 

sources would be able to meet this limit without installing 

additional controls. 

With regard to new sources, as described above, 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. A variability analysis similar to that used for 

existing sources was then performed to calculate a 99 percent UPL 

using the three run test data from the top source. For this source 

category, we calculate that the UPL MACT floor limit for new sources 
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is 16 μg/dscm at 2 percent CO2. This limit is based on the performance 

of the best performing source.

The next step in establishing MACT standards is the 

investigation of regulatory alternatives. We can select an 

alternative standard that is more stringent than the MACT floor level 

of control, if it is technically and economically achievable 

consistent with CAA section 112(d)(2). The statute requires us to 

consider the cost of achieving the emission reduction, 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. Therefore, As described below, we 

considered beyond-the-floor control options to further reduce 

emissions of mercury. Because of our limited data set, The option we 

considered is based on setting a MACT limit for existing sources 

based on the performance of the best performing source (i.e., based 

upon the test data used to calculate the MACT floor for new sources) 

such that the MACT limit for existing sources would be the same as 

the UPL MACT limit for new sources (i.e., 16 μg/dscm). Under this 

option, the best performing source would need no additional controls 

to meet the limit, since their current performance defines the new 

source limit. With regard to the other facility in the source 

category, Aas described below, we believe this limit level could be 

achieved by the addition of an activated carbon injection system, 
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which is a proven technology for mercury control. Compliance would be 

demonstrated by periodic performance testing and continuous parameter 

monitoring. 

In evaluating a beyond the floor option, we must consider the 

cost and technical feasibility of achieving the emission limit. No 

facilities in the source category use add-on control devices or use 

work practices to limit mercury emissions beyond what is normally 

achieved as co-control of the emissions with the particulate matter 

control device. However, we identified both carbon bed technology and 

activated carbon injection as commercially available mercury emission 

reduction techniques. Carbon bed technology (which is one of the 

primary control devices used at Industrial Gold Production facilities 

in the U.S. to minimize mercury emissions, as described in the 

proposed rule for that category33), as described in the proposed 

NESHAP for Gold Mines (75 FR 22470, April 28, 2010)proposed under the 

recent Gold Mine NESHAP) does not appear to be a viable technology to 

control the large volumes of airflow generated by the electric arc 

furnaces in the Ferroalloys Production source category. However, 

activated carbon injection , which has been used to control mercury 

emissions at various types of facilities that have large volumes of 

airflow including some coal-fired power plants, waste incinerators

and cement kilns. ), is considered a viable control option for the 

Ferroalloys Production source category. being considered in other 

 

33 National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore 

Processing and Production Area Source Category. Proposed Rule (75 FR 22470);
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recent NESHAP such as the Utility MACT NESHAP and the Portland Cement 

NESHAP Based on available information, Aactivated carbon injection

appears to be the best control for mercury for these to control

larger volume combustion sources. Mercury reductions of up to 90 or 

905 percent have been are reported at these other sources and should 

also be achievable at ferroalloys production facilities. Therefore, 

bBased on data and information on our experience with these mercury 

controls for other combustion sources (such as utility boilers, 

incinerators and cement kilns), and based on our experience with

these controls, we conclude that activated carbon injection is a 

viable control technology for in the Ferroalloys Production source 

category. Nevertheless, wthis beyond the floor limit, the feasibility 

and costs of these ACI controls, and 

We recognize the potential concern that use of activated carbon 

injection upstream of the particulate matter control device may pose 

issues with fabric filter dust contamination or sludge contamination 

and may result in some waste products being classified as Resource 

Conservation and Recovery Act (RCRA) waste versus the more easily and 

less costly to dispose of industrial waste. In addition, some 

companies re-use or sell their baghouse dust (primarily for use in 

cement kilns). There is also concern that even if the material meets 

quality standards, that re-introduction of the dust into a furnace or 

kiln could cause the mercury to become unbound from the carbon and be 

emitted into the atmosphere. 
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We reviewed facility specific control options that included 

putting the mercury controls downstream of the existing furnace 

baghouse to avoid the potential issues (described above) associated 

with upstream controls. Under this scenario, the activated carbon 

injection system would be followed by a ―polishing‖ baghouse to 

capture the activated carbon for disposal. In the case of the 

existing furnace scrubber, we assumed the source could put the 

activated carbon injection system upstream of the scrubber, the 

carbon would be captured by the scrubber and the resulting sludge 

treated according to the existing treatment process at the plant. 

Based on discussion34 with a vendor and other control technology 

experts, we do not believe that the resulting carbon waste in either 

scenario would trigger the RCRA compliance concerns raised by the 

companies. This is because once the mercury absorbs to the activated 

carbon, it will stay there until heated above 400 degrees Fahrenheit. 

The captured activated carbon should pass the Toxicity Characteristic 

Leaching Procedure test, which is an EPA test method used to 

characterize waste as either hazardous or non-hazardous for the 

purpose of disposal. Therefore, the captured activated carbon would 

unlikely be considered hazardous waste and can be disposed of in a 

landfill.

We estimate that under this beyond the floor option described 

above (i.e., a proposed limit of 16 μg/dscm), that one facility would 

 

34 Conversation with D. Lipscomb, Albemarle. August 22, 2011.
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need to install additional controls such as activated carbon 

injection to meet this e limit of 16 uμg/dscm, and that this would

achieve about 420 pounds of reduction per year in mercury emissions. 

The capitaol costs are estimated to be $1.7 million, annual costs to 

be $1.4 million, with an overall cost-effectiveness of $3,300 per 

pound. The general range of costs for mercury controls from other 

MACT rules has been about $1,250 to $55,200 per pound of mercury 

removed (76 FR 25075, May 3, 2011). However, it is important to note 

that there is no bright line for determining cost-effectiveness. Each 

rulemaking is different and various factors must be considered. 

Nevertheless, the cost-effectiveness of mercury controls in this 

proposed rule for Ferroalloys Production is near the lower end of the 

range. Some of the factors we consider include the following: total 

capital costs; annual costs; costs compared to total revenues (e.g., 

costs to revenue ratios); whether the standards significantly impact 

one or more small businesses; whether the controls would 

significantly impact production; whether, and to what extent, the 

controls result in adverse impacts to other media (e.g., hazardous 

waste issues); and whether, and to what extent, the controls lead to 

increases in other air pollutants (e.g., regenerative thermal 

oxidizers producing NOx or SO2).

Nevertheless, oOverall, we conclude based on our analyses that 

believe these mercury controls are feasible for the Ferroalloys 

Production source category from a technical standpoint and are cost
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effective. Therefore, we are proposing a MACT limit for mercury 

emissions of 16 μug/dscm for both existing and new sources under the 

authority of sections 112(d)(2) and (d)(3). More information 

regarding how the MACT limits were calculated and the costs is 

provided in Ferroalloys Production MACT Floor and Cost Memos, which 

are available in the docket for this rulemaking. The proposed MACT 

limits and potential related issues are also described further below 

under the technology review section of this preamble (section 

IV.D.4).

Nevertheless, wWe are requesting comment on these proposed 

limits for mercury, including the costs and feasibility of meeting 

these limits, and whether a different limit (either higher or lower) 

might be more appropriate. For example, would it be more technically 

feasible and/or cost-effective to have a limit twice this level 

(i.e., 32 μg/dscm), or would it be more appropriate to have a limit 

at 50 percent of this level (i.e., 8 μg/dscm)? If so, we request that 

commenters please provide data and information supporting such 

conclusions.

We also seek comments and information on our conclusion that the 

expected controls to meet this limit are feasible and cost-effective, 

and we seek information, data and comments on the factors (e.g., 

those described above and/or others) that may affect this conclusion 

regarding cost-effectiveness. We specifically seek comments on the 

feasibility and costs of activated carbon injection controls and 
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other possible controls that could be effective to reduce mercury 

emissions and perhaps less costly. We also seek comment on whether 

work practices to minimize mercury emissions, such as switching to 

manganese ores with low mercury content, could be technically and 

economically feasible.

Moreover, we request commenton on, and whether these proposed 

standards are appropriate for all types of manganese production 

operations or if subcategories should be considered for the mercury 

standard. The emission data collected were from one furnace producing 

ferromanganese at one plant and from one furnace producing 

silicomanganese at another plant. We are requesting additional test 

data or analysis that could be used to determine if different

standards would be appropriate for ferromanganese production and 

silicomanganese production processes and what the levels those

standards should be. Specifically, we understand that the production 

of ferromanganese products requires substantially larger amounts of 

ore in the furnace charge than does the production of silicomanganese 

product. A ton of ferromanganese product may require three to six

times as much ore as a ton of silicomanganese product. As a result, 

the mercury concentration in the offgas may be higher as well. Even 

so, we do not believe that subcategorization would have any

substantive effect on the resulting standards or the costs of

controls either the floor (no additional control) or the beyond the 
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floor option since there would be no change in the costs and 

feasibility of mercury controls evaluated for these sources.

The emission data collected were from one furnace producing 

ferromanganese at one plant and from one furnace producing 

silicomanganese at another plant. We are requesting additional test 

data or analysis that could be used to determine if different

standards would be appropriate for ferromanganese production and 

silicomanganese production processes and what the levels those

standards should be.

ANevertheless, any source installing activated carbon injection 

would be required to continuously monitor the carbon injection rate 

into the airstream being controlled. We request comment on the level 

of variability in the carbon injection rate that should be allowed, 

and what percent decrease in the rate should be considered 

significant.

We also propose that sources monitor the mercury content in the 

manganese ore. Specifically, we propose that the determination of a 

significant increase in mercury content would be that the 12- month 

rolling weighted average mercury concentration based on monthly 

sampling in the manganese ore increases by 10 percent or more 

compared to the baseline weighted average mercury concentration. If 

that limit is exceeded, the source would be required to readjust the 

carbon injection rate as specified in the source‘s monitoring plan or 
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retest within 30 days if there is not a dedicated mercury control 

device. If a new ore is added, sampling would be required as well.

Nevertheless, we request comment on this ore monitoring 

provision. We are especially interested in any data that would show 

the variability in mercury concentration between different ore 

samples from the same location and the variability of the types of 

ores used in manganese production. If ore type and mercury content 

are demonstrated to be stable, we might consider reducing the 

frequency of sampling/calculations to quarterly or less. 

2. Polycyclic Aromatic Hydrocarbons (PAHs)

PAH emissions are products of incomplete combustion from the 

smelting operation, and a subset of the listed HAP POM. Some of these 

emissions are likely to be in particulate form, but a significant 

portion is expected to be in a gaseous form. Therefore, the existing 

particulate matter control devices only achieve partial control of 

these compounds. No existing facilities in the source category 

control PAH or use work practices to limit emissions of PAH emissions

specifically. However, under today‘s proposal, these pollutants would 

be controlled with the same activated carbon injection technology as 

mercury. Because of this, emission reductions could be achieved via 

co-control at no additional costs. Nevertheless, the 1999 MACT does 

not include any standards specifically for PAH. Therefore, Ppursuant 

to CAA section 112(d)(2) and 112(d)(3), we are proposing to revise 

the 1999 NESHAP to include an emission limit for PAH.
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We have stack test data from only one furnace for PAH emissions. 

As such, the MACT floor would be based on the performance level 

achieved at that furnace (i.e., the average emissions of that furnace 

plus an amount to account for variability). Based on these data and 

applying the 99 percent UPL, we calculate that the MACT floor limit 

for PAHs would be 887 μg/dscm. We also evaluated control performance 

that could be achieved via co-control of mercury emissions with 

activated carbon injection as a beyond-the-floor option. Based on 

information from carbon vendors, an activated carbon system that is 

designed to achieve a 90 percent reduction in mercury emissions 

(which we expect believe would be applied to meet the proposed 

mercury standard discussed above) should also achieve a high degree 

of reduction in PAH with no additional costs. Assuming a 90 percent 

reduction from the calculated 99 percent UPL of 887 μg/dscm, the 

resulting limit would be 89 μg/dscm (see section IV.D.5 for more 

detail). Thus, a proposed limit for PAHs of 89 μg/dscm could be 

achieved with the same controls needed for mercury with no additional 

costs.

Therefore, pursuant to CAA sections 112(d)(2) and (d)(3), we are 

proposing to revise the 1999 NESHAP to include an emission limit for 

PAH of 89 μg/dscm for new and existing sources.

3. Hydrochloric acidgen chlorideHClAcid Gases

As noted above, the 1999 MACT rule does not include standards 

for acid gases (HCl and HF). Hydrogen chloride (Hydrochloric acid
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(HCl) isThese acid gases are a product of combustion, and the level 

of emissions is dictated by the chlorine and fluorine content of the 

coal or coke used as a reducing agent in the smelting process. Based 

on test data from the ICR, we estimate that the two facilities in 

this source category emit 6 to 11 tpy of HCl. While these levels of 

emissions are nontrivial, they are relatively low compared to some 

other types of combustion sources. The primary reason for this is 

that manganese producers use coke instead of coal as the primary 

reducing agent in the smelting operation. Because coke is a refined 

product, much of the original chlorine content in the coal is removed 

in the coking process, which greatly reduces potential emissions. 

Second, one of the five furnaces at these plants is equipped with a 

scrubber, which provides co-control of particulate matter and HCl

emissions. Because the current rule has no limits for HClthese HAP, 

pIn any case, section 112(d) requires us to set MACT for all listed 

HAP emitted from a source category. Pursuant to CAA section 112(d)(2) 

and 112(d)(3), we are proposing to revise the 1999 NESHAP to include 

emission limits for HClacid gases.

We estimate that the two facilities in this source category emit 

6 to 11 tpy of HCl, and 1 to 7 tpy of HF per facility, respectively. 

While these levels of emissions are nontrivial, they are relatively 

low compared to some other types of combustion sources. The primary 

reason for this is that manganese producers use coke instead of coal 

as the primary reducing agent in the smelting operation. Because coke 
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is a refined product, much of the original chlorine or fluorine 

content in the coal is removed in the coking process, which greatly 

reduces potential emissions. Second, one of the five furnaces at 

these plants is equipped with a scrubber, which provides co-control 

of particulate matter and acid gas emissions. Nevertheless, we 

believe it is appropriate to propose emission limits for HClthese HAP 

in today‘s action.

As discussed above, the MACT floor limit is calculated based on 

the average performance of the units in each category plus an amount 

to account for these units‘ variability. To account for variability 

in the operation and emissions, the stack test data were used to 

calculate the average emissions and the 99 percent UPL to derive the 

MACT floor limit. However, a number (50 percent) of the individual 

data points were reported as below the applicable test detection 

limits.

35 The following discussion describes how we handle such data 

in our MACT calculations. Also, as described below, we request 

comment on how this uncertainty might influence establishing an 

emission limit instead of a work practice standard.

Test method measurement imprecision is a contributor to the 

variability of a set of emissions data. One element is associated 

with method detection capabilities and a second is a function of the 

measurement value. Measurement imprecision is proportionally highest 

 

35 We conducted this analysis for all measured pollutant according to the following 

method when non detects were reported. However only the hydrochloric acid, 

hydrofluoric acid and formaldehyde data needed a detection limit correction to 

adequately account for variability, as described below.
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for values measured below or near a method‘s detection level and 

proportionally lower for values measured above the method detection 

level. 

The probability procedures applied in calculating the MACT floor 

or beyond the floor emissions limit inherently and reasonably account 

for emissions data variability including measurement imprecision when 

the database represents multiple tests from multiple emissions units 

for which all of the data are measured significantly above the method 

detection level. This is less true when the database includes some 

emissions occurring below method detection capabilities that are 

reported as the method detection level values.

The EPA‘s guidance to facilities for reporting pollutant 

emissions in response to the ICR data collection specified the 

criteria for determining test-specific method detection levels. Those 

criteria ensure that there is only about a 1 percent probability of 

an error in deciding that the pollutant measured at the method 

detection level is present when in fact it was absent. Such a 

probability is also called a false positive or an alpha, Type I, 

error. Because of sample and emissions matrix effects, laboratory 

techniques, sample size, and other factors, method detection levels 

normally vary from test to test for any specific test method and 

pollutant measurement. The expected measurement imprecision is 40 to 

50 percent or greater at levels measured at the method detection 

level or less. The expected measurement imprecision decreases to a 
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relative 10 to 15 percent for values measured at a level about three 

times the method detection level or greater.

36

Also in accordance with our guidance, source owners identified 

emissions data which were measured below the method detection level 

and reported those values as equal to the method detection level as 

determined for that test. An effect of reporting data in this manner 

is that the resulting database is somewhat truncated at the lower end 

of the measurement range (i.e., no values reported below the testspecific method detection level). A MACT floor or beyond the floor 

emissions limit based on a truncated database or otherwise including 

values measured near the method detection level may not adequately 

account for measurement imprecision contribution to the data 

variability.

We applied the following procedures to account for the effect of 

measurement imprecision associated with a database that includes 

method detection level data. The following process also addresses the 

concerns associated with use of a small data set, such as the 

Ferroalloys Production data set for HClacid gases. As a first step, 

we reviewed an HCl emissions data set for the industrial boilers 

rule, which represents several hundred emissions tests used in the 

floor calculations (i.e., best performers) for the boilers rule to 

determine typical method detection levels. We have data from multiple 

 

36 American Society of Mechanical Engineers, Reference Method Accuracy and 

Precision (ReMAP): Phase 1, Precision of Manual Stack Emission Measurements, CRTD 

Vol. 60, February 2001.
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industrial boilers tests and used those data to confirm that method 

detection levels testers reported were as good as or better (i.e., 

lower) than the values reported in the method. We presume that data 

for the best performing units also reflect the capabilities of high 

quality testing companies and laboratories. Further, the method 

detection levels calculated from larger data sets are more 

representative of the inherent measurement variability both within 

and between testing companies than the limited Ferroalloys Production 

dataset. We believe that emissions tests conducted with these methods 

for most combustion operations (e.g., fossil fuel, biomass, and waste 

fired units; brick and clay kilns; Portland cement kilns), including 

ferroalloys production, should produce method detection levels very 

similar to the level of 60 μg/dscm that is the result of this review.

We assumed that the representative detection level (RDL) for HF would 

be the same as for HCl.

The second step in the process was to calculate three times the 

RDL and compare that value to the calculated MACT floor or beyond the 

floor emissions limit. We use the multiplication factor of three to 

approximate a 99 percent upper confidence interval for a data set of 

seven or more values. If three times the RDL was less than the 

calculated MACT floor emissions limit calculated from the UPL, we 

would conclude that measurement variability was adequately addressed. 

The calculated MACT floor or beyond the floor emissions limit would 

need no adjustment. If, on the other hand, the value equal to three 
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times the RDL was greater than the UPL, we would conclude that the 

calculated MACT floor or beyond the floor emissions limit does not 

account entirely for measurement variability. If indicated, we 

substituted the value equal to three times the RDL to apply as the 

adjusted MACT floor or beyond the floor emissions limit. This 

adjusted value would ensure measurement variability is adequately 

addressed in the MACT floor or the beyond the floor emissions limit.

For HCl, three times the RDL was less than the calculated 99 

percent UPL for exhaust HCl concentration from existing furnaces. 

Thus, for existing sources, the MACT floor for HCl is set at the UPL, 

or 809 μg/dscm corrected to 2 percent CO2. Similarly, for HF, three 

times the RDL was less than the calculated 99 percent UPL for exhaust 

HF concentration from existing furnaces. Thus, for existing sources, 

the MACT floor for HF is 801 μg/dscm corrected to 2 percent CO2. 

Consistent with CAA section 112(d)(3), the MACT floor for new 

sources cannot be less stringent than the emissions control that is 

achieved in practice by the best-controlled similar source. The 99 

percent UPL calculated for both HCl and HF based on the best 

performing source is less stringent than the MACT floor for HCl and 

HF at existing furnaces. We determined that the use of the best 

performing source UPL is not appropriate in this situation because 

the high variability and small data pool would result in a new source 

MACT floor limit that is less stringent than the limit based on the 

UPL calculated from the larger data pool for existing sources. Given 
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that the 99 percent UPL for new sources is higher than the 99 percent 

UPL for existing sources, we determined that the MACT limit for new 

sources should be equal to the MACT limit for existing sources.

We then considered a beyond-the-floor option to further reduce 

emissions of HCl and HF at existing sources based on application of 

additional add-on control devices, such as lime injection, but their 

use is not indicated given the high costs of installing and operating 

such controls. There is also concern that use of this technology 

could prevent the current practice of reusing or selling baghouse 

dust and the resulting waste reduction benefits. See the Draft MACT 

Floor Analysis for the Ferroalloys Production Source Category in the 

docket for more discussion of this topic.

Therefore, pursuant to CAA sections 112(d)(2) and 112(d)(3), we 

are proposing to revise the 1999 NESHAP to include emission limits 

for new and existing sources for HCl and HF of 809 μg/dscm and 801 

μg/dscm, respectively. At this level, we do not anticipate that 

either source would be required to install controls to meet the 

limits. For more information on how these limits were derived, see 

the Draft MACT Floor Analysis for the Ferroalloys Production Source 

Category. As described above, there are some measurements (i.e., 50 

percent) reported as below the method detection level. Because of the 

potential uncertainty in basing a limit partially on non-detect 

values, we considered the possibility of proposing work practice 

standards such as a limit on the amount of coal (the primary source 
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of chlorine in the raw materials) in lieu of numerical emission 

limits. We request comment on whether this or other work practices 

might be appropriate.

4. Formaldehyde

Formaldehyde emissions are also products of incomplete 

combustion from the smelting operation. The existing particulate 

matter control devices only achieve partial control of these volatile 

compounds. Based on test data from the ICR, we estimate that the two 

facilities in this source category emit approximately 2 tpy of 

formaldehyde. Pursuant to CAA section 112(d)(2) and 112(d)(3), we are 

proposing to revise the 1999 NESHAP to include emission limits for 

formaldehyde.

The measured average formaldehyde emissions ranged from 57 to 78 

μg/dscm corrected to 2 percent CO2. Because the formaldehyde emissions 

data included some many data points (50 percent) reported as below 

the detection limit, we employed a version of the methodology used 

for HClacid gases to determine set the MACT floor. However, in this 

case we lack the underlying large data set of formaldehyde method 

detection limits that we had for HCl method detection limits. In this 

case, the first step was to define a method detection level that is 

representative of the data used in defining the best performers for 

the inclusive source category (i.e., combined data for all 

subcategories). We identified all of the available reported pollutant 

specific method detection levels and calculated the arithmetic mean 
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value. We deemed the resulting mean of the method detection levels as 

the (RDL). Three times the RDL was greater than the calculated 99 

percent UPL for exhaust formaldehyde concentrations from existing 

furnaces, resulting in a MACT floor of three times the RDL, or 201 

μg/dscm at 2 percent CO2. Based on available data, all of the existing

sources could meet this limit without installing additional controls. 

Due to the high variability in the data pool, the 99 percent UPL 

for the best-performing source is less stringent than the existing 

source MACT floor. Therefore, pursuant to CAA section 112(d)(2) and 

112(d)(3), we are proposing to revise the 1999 NESHAP to include an

emission limit for formaldehyde for new and existing sources of 201 

μg/dscm based on the MACT floor calculation. We have not identified 

any appropriate beyond-the-floor control technology options 

specifically for formaldehyde. We recognize the potential for some 

co-control of formaldehyde emissions that would be achieved by using 

activated carbon injection to control mercury emissions, but we were 

unable to quantify those reductions. More information regarding how 

the MACT limits were calculated and the costs is provided in 

Ferroalloys Production MACT Floor and Cost Memos, which are available 

in the docket for this rulemaking. Finally, because of the potential 

uncertainty in basing a limit partially on non-detect values, we 

considered the possibility of proposing work practice standards. We 

request comment on whether there are any work practices that might be 

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

As described above, for the Ferroalloys Production source 

category, we conducted an inhalation risk assessment for all HAP 

emitted. We also conducted multipathway screening analyses for 

mercury and POM. Details of the risk assessment and additional 

analyses can be found in the residual risk documentation referenced 

in section III.B of this preamble, which is available in the docket 

for this action. The Agency considered the available health 

information -- the MIR; the numbers of persons in various risk 

ranges; cancer incidence; the maximum non-cancer HI; the maximum 

worst-case acute non-cancer HQ; the extent of non-cancer risks; the 

potential for adverse environmental effects; and distribution of 

risks in the exposed population (54 FR 38044, September 14, 1989) –

in developing the proposed CAA section 112(f)(2) standards for the 

Ferroalloys Production source category.

1. Inhalation Risk Assessment Results

Table 5 of this preamble provides an overall summary of the 

results of the inhalation risk assessment. 

Table 5. Ferroalloys Production Inhalation Risk Assessment Results

Maximum Individual 

Cancer Risk (in 1 

million)1 Estimated 

Population at 

increased 

Risk of 

cancer ≥ 

1-in-1 

Million

Estimated 

Annual 

Cancer 

Incidence 

(cases 

per year)

Maximum Chronic 

Non-cancer TOSHI3 Maximum 

Screen

-ing 

Acute 

Noncancer 

HQ4

Based on 

Actual 

Emissions 

Level2

Based on 

Allowable 

Emissions 

Level

Based on 

Actual 

Emissions 

Level

Based 

on 

Allowable 

Emissions 

Level

80 100 26,000 0.002 90 200 10
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1 Estimated maximum individual excess lifetime cancer risk due to HAP emissions from 

the source category.

2 Based on the consistent views of major scientific bodies (i.e., NTP in their 12th

Report on Carcinogens, IARC, and other international agencies) that consider all 

nickel compounds to be carcinogenic, we currently consider all nickel compounds to 

have the potential of being as carcinogenic as nickel subsulfide. To implement this 

approach we apply the nickel subsulfide IRIS URE without a factor to reflect the 

assumption that 100 percent of the total mass of nickel may be carcinogenic. 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 a plausible 

range of cancer potency values for different mixtures of nickel compounds.. If the 

lower end of the nickel URE range is used, the maximum individual lifetime cancer 

risk based on actual emissions would be 50 in 1 million. The allowable cancer risk 

would remain 100 in a million because at one facility nickel is not the primary

cancer driver. The estimated annual cancer incidence would also be reduced, but due 

to our presentation of incidence to one significant figure, remains 0.002. 

Estimated population values are not scalable with the nickel URE range, but would 

be lower using the lower value.

3 Maximum TOSHI. The target organ with the highest TOSHI for the Ferroalloys 

Production source category is the central nervous system. 

4 The maximum off-site HQ acute value of 10 is driven by emissions of nickel. See 

section III.B of this preamble for explanation of acute dose-response values.

The results of the chronic baseline inhalation cancer risk 

assessment indicate that, based on estimates of current actual 

emissions, the current maximum individual lifetime cancer risk posed 

by these two facilities could be up to 80 in one million (50 in one 

million with the lower nickel URE value), with process fugitive

emissions (from the furnace, crushing operation, and casting) of 

nickel, chromium and arsenic as major contributors to the risk. The 

total estimated cancer incidence from this source category based on 

actual emission levels is 0.002 excess cancer cases per year or one 

case in every 500 years, with emissions of nickel, chromium and 

arsenic contributing 36 percent, 24 percent and 24 percent 

respectively, to this cancer incidence. In addition, we note that 

approximately 1,100 people are estimated to have cancer risks greater 

than 10 in one million, and approximately 26,000 people are estimated 

to have risks greater than one in one million as a result of 
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emissions from these two facilities. When considering the risks

associated with MACT-allowable emissions, both facilities have 

allowable risks of 100 in one million, driven by nickel, chromium VI, 

and arsenic at one facility (which would have an allowable cancer 

risk of 70 in one million when using the lower nickel URE value) and 

chromium VI and arsenic at the other facility (which would have an 

allowable cancer risk of 100 in one million when using the lower 

nickel URE value).the MIR could be up to 100 in one million.

The maximum modeled chronic non-cancer TOSHI value for the 

source category could be up to 90 with emissions of manganese from 

process fugitives contributing greater than 90 percent of dominating 

those impacts. A TOSHI of 90 means that the modeled long-term average 

air concentration of manganese at that location is about 4.5 μg/m3, or 

90 times above the RfC (i.e., 0.05 μg/m3). A comparison of modeled 

concentrations to monitored values (from the EPA‘s School Air Toxics 

Initiative mentioned in Section II.C) is available in the risk 

assessment document in the docket. 

Approximately 28,000 people are exposed to TOSHI levels above 1. 

At exposure levels above a TOSHI level of 1 (i.e., the RfC for 

manganese), manganese can cause central nervous system effects. 

However, the EPA cannot state at what exposure level there will be an 

appreciable risk of deleterious effects. Visual reaction time, hand 

steadiness, and eye-hand coordination effects have been reported in 

chronically-exposed workers. When considering MACT-allowable 
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emissions, the maximum chronic non-cancer TOSHI value could be up to 

200. As the RfC is the level below which there is not likely to be 

appreciable risk of deleterious effects, the EPA looks carefully at 

values that are above the RfC. This includes evaluation of the 

potential adverse effect, the concentration at which these effects 

are observed and the application of adjustment and uncertainty 

factors that generally reflect limitations in the database. The EPA 

has medium confidence in the RfC value of 0.00005 mg/m3, which 

reflects the overall level of certainty in the principle studies and 

database.37 Using an IRIS RfC value ensures consistency with our 

priority scheme for the sources of dose-response values to be used in 

our inhalation risk assessments (as described in Section III.B.3). 

Nevertheless, Wwe request public comment on the weight given to the 

non-cancer risk assessment, based on the RfC for manganese, in the 

overall determination of whether risks are unacceptable, which is 

described in section IV.C.1. risk.

As mentioned earlier (in section II), ambient concentrations of 

manganese were monitored at three schools located near one of the 

regulated ferroalloy production facilities during the EPA‘s School 

Air Toxics Initiative in late 2009. The concentrations were observed 

to be above the RfC for all three sites. In addition, we compared 

these monitored concentrations of manganese to predicted modeled 

concentrations of manganese at receptors in close proximity to the 

 

37 IRIS Manganese (1995) http://www.epa.gov/iris/subst/0373.htm.
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monitors. At these three locations, model predictions are generally 

within a factor of two when compared to monitored concentrations at 

these sites. These results indicate that AERMOD estimates of ambient 

air manganese concentrations provide a reasonable representation of 

the measured maximum manganese concentrations present in the ambient 

air near this facility. More information about the EPA‘s School Air 

Toxics Initiative can be found at . More information about the model 

results and the model to monitor comparison can be found in the Risk 

Assessment document, which is available in the docket. 

Our screening analysis for worst-case acute impacts indicates 

the potential for two pollutants, nickel and arsenic, to exceed an HQ 

value of 1, with a potential maximum HQ as high as 10 for nickel and 

9 for arsenic based on acute REL values for each substance. There are 

no AEGL, ERPG, or short-term occupational values for these pollutants

to use as comparison to acute REL values, as has been done for 

formaldehyde in other RTR actions. These acute result values were 

based on maximum hourly emissions estimates and a review of the 

facility boundaries to make sure the estimated impacts were off 

facility property. Refer to Appendix 1 of the Risk Assessment 

document in the docket for a detailed description of how the maximum 

hourly emissions were developed for this source category. These 

results suggest there may beBased on these results, we cannot rule 

out the potential for acute impacts of concern from the emissions of 

nickel and arsenic from the two facilities in this category. In 
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characterizing the potential for acute noncancer 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 uncertainties related to the 

emissions estimates and the screening methodology.

2. Multipathway Risk Assessment and Results

The PB-HAP emitted by facilities in this category include 

mercury, POM (as benzo(a)pyrene toxicity equivalents, or TEQ), and 

lead. To identify potential multipathway health risks from PB-HAP 

other than lead, we first performed a screening analysis that 

compared emissions of other PB-HAP emitted from the Ferroalloys 

Production source category to emission threshold values. The two 

facilities in the source category reported emissions of mercury and 

POM, and both of them had baseline emission rates greater than the 

screening emission threshold values for the pollutants indicating 

that there may be potential multipathway impacts of concern due to 

emissions of these pollutants from these two facilities. One 

facility‘s emission rates of mercury exceeded the screening threshold 

by 30 times, while the other facility‘s mercury emissions exceeded 

the threshold by 7 times. For POM, one facility‘s emission rates 

exceeded the screening threshold by 600 times, while the other 

facility‘s emission rates exceeded the threshold by 50 times. For 

mercury, exceeding the screening emission threshold value relates to 
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a potential for creating a chronic noncancer hazard quotient in 

excess of 1. For POM, exceeding the screening emission threshold 

value relates to a potential for creating a cancer risk in excess of 

one in one million.

Since the two PB-HAP did not screen out during our initial

screening analysis, we refined our analysis somewhat with some 

additional site-specific information to develop an ―intermediate 

screen,.‖ which is a more realistic analysis but still considered a 

screening analysis. (See Appendix 5 of the Risk Assessment document

in the docket for more information about this intermediate screen.) 

The additional site-specific information included land use around the 

facilities, the location of fishable lakes, and local wind direction 

and speed. The result of this analysis was the development of sitespecific emission screening thresholds for POM and mercury. Based on 

this intermediate screening analysis, neither facility screened out, 

meaning that we cannot rule out the potential for multipathway 

impacts of concern due to emissions of these pollutants from these 

two facilities. One facility‘s emission rates exceeded the sitespecific screening threshold for mercury by 4 times, while the other 

facility‘s emission rates equaled the threshold value. For POM, one 

facility‘s emission rates exceeded the site-specific screening 

threshold for POM by 60 times, while the other facility‘s emission 

rates exceeded the threshold by 5 times. We were unable to obtain the 
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data necessary to conduct a fully refined assessment of multipathway 

risks from these two facilities.

In evaluating the potential for multipathway effects from 

emissions of lead, modeled maximum annual lead concentrations were 

compared to the National Ambient Air Quality Standards (NAAQS) for 

lead (0.15 μg/m3). Results of this analysis estimate that the NAAQS 

for lead could be exceeded at one of the two facilities, largely due 

to process fugitive emissions. This analysis estimates that the 

annual lead concentrations could be as high as two times the NAAQS 

for lead, and if the maximum 3-month rolling average concentrations 

were used, the result could be even greater concentrations above the 

NAAQS. However, this additional analysis was not conducted because, 

as shown below (in section IV.C.2), the maximum annual lead 

concentration after the proposed controls are applied is 

significantly below the NAAQS, with a value of 0.02 μg/m3.

3. Facilitywide Risk Assessment Results

For both facilities in this source category, there are no other 

significant HAP emissions sources present beyond those included in 

the source category. All significant HAP sources have been included 

in the source category risk analysis. Therefore, we conclude that the 

facilitywide risk is essentially the same as the source category risk 

and that no separate facilitywide analysis is necessary.

C. What are our proposed decisions based on risk acceptability and 

ample margin of safety?
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1. Risk Acceptability 

As noted in section III.C of this preamble, we weigh all health 

risk factors in our risk acceptability determination, including the 

MIR; the number of persons in various risk ranges; cancer incidence; 

the maximum noncancer HI; the maximum acute noncancer HQ; the extent 

of noncancer risks; the potential for adverse environmental effects; 

distribution of risks in the exposed population; and risk estimation 

uncertainty (54 FR 38044, September 14, 1989).

As the D.C. Circuit held in NRDC v. EPA, 529 F.3d 1077, 1082

(D.C. Cir. 2008), section 112(f)(2) ―incorporates EPA‘s 

 ̳interpretation‘ of the Clean Air Act from the Benzene Standard, and 

the text of this provision draws no distinction between carcinogens 

and non-carcinogens.‖ As the D.C. Circuit held, there is nothing on 

the face of the statute that limits the Agency‘s section 112(f)

assessment of risk to carcinogens. Id. at 1081 – 82. Indeed, in the 

NRDC case, the petitioners argued, among other things, that section 

112(f)(2)(B) applied only to non-carcinogens. The D.C. Circuit flatly 

rejected this position, holding that the text of that provision

―draws no distinction between carcinogens and non-carcinogens,‖ and 

that Congress‘ incorporation of the Benzene standard applies equally 

to carcinogens and non-carcinogens.

Moreover, the Benzene NESHAP analysis referenced in CAA section 

112(f)(2)(B) is based on EPA‘s interpretation of CAA section 112 as 

it existed prior to the 1990 CAA Amendments. The pre-1990 version of 
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section 112 also used the phrase ―ample margin of safety‖ and, in no 

way, distinguished between cancer and non-cancer risks. Inherent in 

determining what is an ―ample margin of safety‖ is determining what 

level of risk is acceptable, which is the first step in a Benzene 

NESHAP analysis. See NRDC v. EPA, 824 F.2d at 1164 (Vinyl Chloride) 

(―We find that the congressional mandate to provide  ̳an ample margin 

of safety‘  ̳to protect the public health‘ requires the Administrator 

to make an initial determination of what is  ̳safe.‘‖). Congress 

incorporated the same ample margin of safety language in section 

112(f)(2), and as the D.C. Circuit recognized in NRDC , that language 

calls for the Agency to assess both carcinogens and non-carcinogens 

in evaluating whether the MACT standards ―provide an ample margin of 

safety to protect public health.‖ Nothing on the face of the statute 

suggests that in reviewing the risk associated with a source category 

the Agency can ignore non-carcinogens. Such a reading is wholly 

unsustainable and contrary to D.C. Circuit precedent. 

Based on the baseline inhalation risk assessment, we estimate 

that the cancer risks to the individual most exposed could be up toas 

high as 80 in one million (50 in one million when using the lower 

nickel URE value) due to actual emissions of arsenic, chromium and 

nickel from process fugitives and up toas high as 100 in one million 

due to MACT-allowable emissions, mainly due to chromium, and arsenic 

and nickel stack emissions. (There is no change in the allowable 

cancer risk estimate when using the lower nickel URE value.) We 
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estimate that the incidence of cancer based on actual emissions is 

0.002 excess cancer cases per year, or 1 case every 500 years, and 

that about 26,000 people face a cancer risk greater than one in one

million due to HAP emissions from this source category. The chronic 

noncancer TOSHI could be up toas high as 90 due to actual emissions 

of manganese from process fugitives and up toas high as 200 due to 

MACT-allowable emissions of manganese from process fugitives. We 

estimate that about 28,000 people face a TOSHI level greater than 1 

due to emissions from this source category.

With respect to potential acute non-cancer health risks, we 

estimate that, based on our refined analysis, the worst-case HQ value 

could exceed an HQ value of 1 for two pollutants, nickel and arsenic, 

with a potential maximum HQ up toas high as 10 for nickel and 9 for 

arsenic. This indicates a potential acute concern relative to the 

baseline emissions of these two pollutants. In characterizing the 

potential for acute noncancer impacts of concern, it is important to 

remember the upward bias of these exposure estimates and to consider 

the results along with the uncertainties related to the emissions 

estimates and screening methodology. Our assessment also indicatesd

the potential for multipathway impacts of concern based on the 

intermediate screening assessment due to baseline emissions of 

mercury and POM. Data were unavailable to conduct a fully refined 

assessment of multipathway risks from these two facilities.
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The risk assessment for this source category was based on 

facility-specific stack-test data and emissions estimates, giving us

a generally high degree of confidence in the results. We applied a 

two-step analysis in the Benzene NESHAP to assess emissions from this 

source category. As noted above, we had allowable cancer risks of 100 

in a million, actual cancer risks of 80 in a million and high indices 

for non-cancer effects. Considering all of the above information, we 

are proposing that the risks are unacceptable, both for the actual 

emissions scenario and for the MACT-allowable emissions scenario. The 

decision that risks are unacceptable for this source category is 

primarily based on the fact that the maximum chronic noncancer HI 

values (90 based on actual emissions, 200 based on allowable, both 

dominated by manganese emissions) are considerably higher than 1 (an 

HI exposure level of 1 is generally considered to be without 

appreciable risk of adverse health effects). The fact that 28,000 

people are estimated to have exposures greater than an HI of 1 (based 

on actual emissions) also weighs considerably in this decision. The 

fact that maximum individual cancer risks are also well above 1 in a 

million also contributes to our determination of unacceptability, but 

to a lesser extent. While the estimated maximum individual cancer 

risks would, by themselves, not generally lead us to a determination 

that risks are unacceptable, the fact that they occur along with the 

high chronic noncancer risks adds to our concern about these 

exposures, and further supports our decision that risks are 
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unacceptable. While the total estimated cancer incidence (0.002 cases 

per year) is also not very high, we note that there are only 2 

sources in the source category, so we would not expect it to be very 

high. We further note that, while our screening for potential acute 

and multi-pathway impacts of concern from the 2 sources in the 

category did identify some potential concerns for a few HAPs, these 

results did not weigh heavily in our determination that risks are 

unacceptable, primarily because we did not have the data that would 

allow us to refine our analysis for such impacts, leaving them 

subject to significant uncertainties.

Given that chronic noncancer risks associated with manganese 

emissions are the primary determinant of unacceptable risks, we 

provide here a brief discussion of the EPA‘s RfC associated with the 

inhalation of manganese and our confidence in the principal studies 

supporting the development of that RfC for context. In the case of 

manganese, the RfC derived in EPA‘s IRIS database is based on its 

ability to cause central nervous system effects. The EPA has medium 

confidence in the RfC value of 0.00005 mg/m3. The confidence level 

reflects the overall level of uncertainty in the principle studies, 

which were based on human occupational studies, and the database.

Overall confidence in the principal studies (Roels et al., 1987, 

1992) and database is medium. Neither of the principal studies 

identified a no observed adverse effect level (NOAEL) for 

neurobehavioral effects, nor did either study directly measure 
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particle size or provide information on the particle size 

distribution. The principal studies found similar indications of 

neurobehavioral dysfunction, which was consistent with the results of 

other human studies. In addition, the 1992 Roels et al. study 

provides sufficient information to establish individual integrated 

exposures; the 1987 Roels et al. study did not.

Confidence in the database on manganese health effects is 

medium. The duration of exposure was relatively limited and the 

workers were relatively young in all of the principal and supporting 

studies. These temporal limitations raise concerns that longer 

durations of exposure and/or interactions with aging might result in 

the detection of effects at lower concentrations, as suggested by 

results from other studies. In addition, the studies, with the 

exception of the 1992 Roels et al. study in which manganese exposure 

was limited to manganese oxide, did not specify the species of 

manganese to which workers were exposed. It is not clear whether 

certain compounds or oxidation states of manganese are more toxic 

than others. Although the primary neurotoxicological effects of 

exposure to airborne manganese have been qualitatively well 

characterized by the general consistency of effects across studies, 

the exposure-effect relationship remains to be well quantified, and a 

no-effect level for neurotoxicity has not been identified in any of 

these studies thus far. Finally, the effects of manganese on 

development and reproduction have not been studied adequately. See 
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the full IRIS summary for manganese for more information (IRIS,

Manganese, available at: www.epa.gov/iris/subst/0373.htm).

We solicit comment on this proposed decision that risks are 

unacceptable. If data and information received in the comment period 

lead us to reverse this determination (i.e., to make a finding that 

the risks presented by the source category are acceptable), then we 

are still required under CAA section 112(f)(2)(A) to make a 

determination as to what controls are needed to achieve an ample 

margin of safety for the source category. The discussion of the 

controls needed to achieve an ample margin of safety in section 

IV.C.3 addresses both what would be needed if we find risks are 

unacceptable as well as what would be needed if we find that risks 

are acceptable.finding. (Additional discussion on the manganese can 

be found in Section IV.B.1.) also conclude that the current chronic 

noncancer risks based on actual emissions are unacceptable, primarily 

due to manganese emissions from process fugitives. 

2. Proposed controls to address unacceptable risks

We conducted an assessment to estimate the risks from the two 

facilities in the source category based on a post-control scenario 

reflecting the proposed requirements described above to address 

unregulated HAP (section IV.A) and the proposed controls described 

below. Details are provided in the Draft Risk Assessment report which 

is available in the docket for this action. 

a. Allowable stack emissions.
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In order to ensure that the risks associated with this source 

category are acceptable, we evaluated the potential to reduce MACTallowable stack emissions, which had driven the cancer MIR based on 

allowable emissions to 100 in a million, primarily due to allowable 

stack emissions of arsenic, nickel and chromium, and contributed 

significantly to the chronic noncancer TOSHI (based on allowable 

emissions) of 200, 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 

process, to develop limits that are achievable with existing

controls. After the implementation of these tighter PM stack limits, 

the estimated cancer MIR for the source category based on allowable 

emissions would become 80 in one million and the TOSHI would be about 

90.

For the reasons described above, under the authority of CAA 

section 112(f)(2), we propose to set particulate matter emission 

limits for the stacks at levels indicative of current performance 

(i.e., based on a MACT floor UPL analysis) as discussed in section 

IV.D.1 (technology review section). These new allowable emissions 

limits levels will reduce potential risks due to allowable emissions 

from the stacks and prevent backsliding. We propose that compliance 

for existing sources will be demonstrated by annual stack testing and 
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installation and operation of bag leak detection systems for both new 

and existing sources. 

b. Process fugitive emissions sources.

Process fugitive sources are partially controlled by the 

existing MACT 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(d)(2) 

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 several options to achieve 

improved emissions capture. We developed several control scenarios to 

assess options to improve/add local ventilation and associated 

control (e.g., improve tapping capture, install capture and control 

on casting operations), but we concluded that these were all 

ineffective in significantly reducing emissions and risks. As part of 

the technology review process, we identified a furnace building 

ventilation system at a non-manganese producer of ferroalloys. We 

evaluated an option based on this furnace building ventilation 

system, which involves enclosing the furnace building(s) and 

evacuating the emissions to a control device(s). Based on our 

assessment we conclude that this option would reduce process fugitive 
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emissions by about 98 percent and reduce the maximum noncancer TOSHI 

to about 2. A TOSHI of 2 means that the modeled long-term 

concentration of manganese at that location would be about 0.1 μg/m3 

(i.e., about 2 times higher than the RfC). These controls would also 

significantly reduce the emissions of arsenic, chromium and nickel 

and therefore significantly reduce the cancer risks. These reductions 

would result in risks to acceptable risk levels. Therefore, under the 

authority of CAA section 112(f), we are proposing such an approach, 

whereby the furnace buildings must be enclosed and fugitive emissions 

would need to be collected under negative pressure at the ridge vents 

of the shop building would need to be collected under negative 

pressure and ducted to a control device. 

We are proposing that the PM emissions limit (as a surrogate for 

particulate metal HAP) at the control device would be the same as it 

is for the furnace stacks (24 mg/dscm). This would allow sources the 

option to duct some or all process fugitive emissions to an existing 

furnace control device if it has excess capacity. If the existing 

control device at the facility does not have sufficient excess 

capacity to handle the captured emissions, the facility would have to 

install additional controls capable of complying with the proposed 

emission limit.

The source would also have to monitor building opacity, prepare 

and operate according to a process fugitives ventilation plan and 

conduct annual performance testing of the building ventilation 
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control device to demonstrate compliance with the proposed standards. 

Baghouses would be required to be equipped with BLDS. We also propose 

that facilities would need to continue the practices to minimize 

outdoor fugitive dust emissions that are required by the 1999 MACT 

rule which includes implementing measures specified in their outdoor 

fugitive dust control plans as approved by the Administrator. 

However, recognizing that there may be other control measures 

that could achieve equivalent emissions reductions that we have not 

yet identified, and to provide some flexibility for facilities to 

determine the best approach to reduce their emissions, we are also 

proposing an equivalent alternative compliance approach. Under this 

alternative approach, we propose that facilities would still need to 

continue the work practices to minimize outdoor fugitive dust 

emissions that are required by the 1999 MACT rule which includes 

implementing measures specified in their outdoor fugitive dust 

control plans as approved by the Administrator. However, in lieu of 

building the full enclosure and capture and evacuation system 

described above to control process fugitive emissions, we are 

proposing that facilities can design and implement an equivalent 

alternative approach (e.g., local capture, controls, and work 

practices) to oaddress the risks associated withf those process 

fugitive emissions. Compliance would be demonstrated by ensuring 

facilities apply the equivalent alternative approach to control 

process fugitive emissions, continue the work practices to minimize 
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outdoor fugitive dust emissions, and also conduct fenceline 

monitoring to demonstrate that the ambient concentration of manganese 

at their facility boundary is no more than 0.1 μg/m3 on a 60-day 

rolling average, as described below. 

However, we acknowledge that there may be other control measures 

and alternative approaches that we have not identified that are 

effective in reducing process fugitive emissions from the furnace 

building. Therefore, as an alternative to the requirement to enclose 

the furnace building(s) and evacuate the emissions to a control 

device(s), we are proposing a fenceline action level that would serve 

as a trigger for corrective action should such level be exceeded. 

This monitoring alternative is designed to allow for flexibility and 

prevent redundant requirements.

Specifically, we propose to require that sources seeking to use 

this alternative prepare and submit for the Administrator‘s approval 

a written plan describing and explaining the equivalent alternative 

approach that they propose to apply and a proposed compliance 

monitoring network that must consist of at least two monitors located 

at or near the facility boundary, and in locations expected to have 

the highest concentrations of manganese, and the procedures for 

sampling, sample handling and custody, sample analysis, quality 

assurance, and recordkeeping procedures. The purpose of the ambient 

air monitoring network would be to ensure that manganese 

concentrations in air near the facility boundaries remain at or below 
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0.1 μg/m3 based on 10-sample rolling averages, with samples being 

collected every 6 days (i.e., 60-day rolling averages). The 

monitoring plan must include a minimum of two monitoring sites that 

are placed in locations that are most likely to capture measurements 

of the maximum concentrations at or near the facility boundaries. For 

example, at least one monitor must be placed in the predominant 

downwind direction from main emissions sources based on historical 

weather patterns in the area. This standard for manganese emissions 

would be a surrogate for all particulate HAP metals (including 

arsenic, nickel and chromium) since they are emitted by the same 

processes and controlled with the same devices and measures. We 

propose to set this alternative limit using manganese as a surrogate 

for metal HAP because manganese is the primary HAP metal emitted from 

this source categorypollutant of concern driving the hazard index. We 

considered the feasibility of using PM as a surrogate, but developing 

a reliable relationship between fenceline manganese concentration and 

filterable PM concentration is almost impossible. We request comment 

on the use of manganese as a surrogate for HAP metals in the 

alternative approach.

This alternative regulatory requirement would provide 

flexibility to facilities in determining the within-facility emission 

sources that should be captured and vented to a control device that 

are most effective for reducing process fugitive emissions at their 

facilities. However, any facility considering this alternative
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approach would need to demonstrate that they will be able to can be 

expected to achieve the necessary reductionsfenceline limitation with 

the proposed alternative approach and obtain approval from the 

Administrator. This is especially important for facilities with a 

history of elevated ambient manganese concentrations based on 

monitoring by state regulatory agencies or the EPA, or any facility 

that has been confirmed as the main contributor to elevated monitored 

manganese concentrations in a particular area. Nevertheless, we are 

seeking comments on this proposed alternative requirement, including 

the controls and practices that can achieve the equivalent level of 

reductions, the averaging time for monitoring, and whether two 

monitors would be sufficient or if more monitors may be warranted.

We propose that if the 10-sample rolling averages exceed the 

specified concentration then corrective actions must be implemented. 

Upon the first exceedance of a 10-sample rolling average, the source 

would be required within 6 months to evaluate the capture and control 

of process fugitives from the furnace building, evaluate other 

potential sources of fugitive emissions, and then implement any 

changes indicated to reduce fugitives to levels that would result in 

air concentrations below 0.1 μg/m3 based on 10-sample rolling 

averages. Upon a subsequent exceedance of the 10-sample rolling 

average following the 6-month evaluation and implementation period, 

the source would be required to comply with the requirement to 

enclose the furnace building(s) and evacuate the emissions to a 
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control device(s). In this case, the source would be required to 

complete the enclosure within 1 year from the time the subsequent

exceedance occurs.

In order to avoid delays in complying with process fugitives 

standards, we propose to require that the written plan be submitted 

within 45 days of the effective date of the final rule so that all 

necessary planning, equipment acquisition, and system development can 

take place before the 2-year compliance date. In this way, if the 

source determines that the use of such system is unlikely to be an 

effective alternative to the building enclosure option, the source 

would be able to comply with the primary option by the compliance 

date of the final rule.

We propose to set the fenceline concentration action level at 

0.1 μg/m3 to reflect the equivalentcomparable level of emissions 

controlrisk that we estimate will be achieved is estimated to remain 

after compliance with the requirement to enclose the furnace 

building(s) and evacuate the emissions to a control device(s). As 

described in section IV.D.2, the maximum modeled chronic noncancer 

inhalation TOSHI value iswould be 2 after full enclosure and 

evacuation of emissions , based on because the post-control modeling

analysis. This means that the modeled concentration at the maximum 

impact location after these controls are in place would be 0.1 μg/m3, 

which is 2 times higher than indicates the maximum ambient 

concentration of manganese would be twice the current value of the 
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value of the RfC for manganese. Therefore, a value twice this 

concentration, achieving and maintaining an air manganese level of 

0.1 μg/m3, at the facility boundary is proposed as the equivalent 

alternative standard to minimize emissions of HAP metals. fenceline 

action level. We request comment on whether the action level should

instead be based on the actual RfC of 0.05 μg/m3 to ensure that 

variations in ambient concentrations of manganese over the course of 

the 10-sample period will remain at acceptable levels. We note that 

the RfC is not designed to be a regulatory limit, and it is defined 

as ―An estimate (with uncertainty spanning perhaps an order of 

magnitude) of a continuous inhalation exposure to the human 

population (including sensitive subgroups) that is likely to be 

without an appreciable risk of deleterious effects during a lifetime. 

It can be derived from a NOAEL, LOAEL, or benchmark concentration, 

with uncertainty factors generally applied to reflect limitations of 

the data used.‖38 Therefore, wNevertheless, we request comment on 

other concentration values that might be appropriate to serve as the 

action concentration level for fenceline monitoring under this 

alternative. The proposed averaging period is consistent with the 

School Air Toxics Initiative ambient air monitoring program, but Wwe 

also request comment on whether a different averaging period should 

be required.

 

38 IRIS Glossary. http://www.epa.gov/iris/help_gloss.htm
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As part of this alternative, we are also proposing a provision 

that would allow for reduced monitoring if the facility demonstrates 

ambient manganese concentrations less than 50 percent of the ambient 

manganese concentration limit for 3 consecutive years at each 

monitor. We propose that a revised monitoring plan may be submitted 

(for review and possible approval by the Administrator) to reduce the 

sampling and analysis frequency if all of the 10-sample rolling 

average concentrations at each monitor are less than 50 percent of 

the limit of 0.1 μg/m3 over a 3-year period.

All of these proposed controls are described further under the 

technology review (in section IV.D.2.) of this preamble.

c. Results of the post-control risk assessment.

The results of the post-control chronic inhalation cancer risk 

assessment indicate that, based on actual emissions, the maximum 

individual lifetime cancer risk posed by these two facilities, after 

the implementation of the proposed controls, could be up to 5 in one

million, reduced from 80 in one million (i.e., pre-controls), with an 

estimated reduction in cancer incidence to 0.0004 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 one in one million would be reduced from 

26,000 to 1,300.

The results of the post-control assessment also indicate that, 

based on actual emissions, the maximum chronic noncancer inhalation 
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TOSHI value would be reduced to 2, from the baseline estimate of 90. 

The number of people estimated to have a TOSHI greater than 1 would 

be reduced from 28,000 to less than 10.

We also estimate that after the implementation of controls, the 

maximum worst-case acute refined HQ value would be reduced from a 

potential high of 10 to 0.3 (based on the REL value for nickel 

compounds) eliminating any potential for acute impacts of concern. 

Considering post-control emissions of multipathway HAP, mercury 

emissions would be reduced approximately 88 percent, while POM 

emissions would be reduced approximately 66 percent from the baseline 

emission rates. Based on our intermediate screening approach for 

multipathway risks, emissions of mercury ―screen out,‖ or are reduced 

below the screening threshold for both facilities, indicating no 

potential for multipathway impacts of concern due to mercury. 

However, emissions of POM (as benzo(a)pyrene TEQ) remain above the 

intermediate screening thresholds for both facilities (one by a 

factor of 20 and one by a factor of 2), indicating that we cannot 

rule out the potential for multipathway impacts of concern due to 

emissions of POM from these facilities. As mentioned above, the 

highest lead concentration after controls, 0.02 μg/m3, is well below 

the NAAQS, indicating a low potential for multipathway impacts of 

concern due to lead.

3. Ample margin of safety analysis and proposed controls
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Under the ample margin of safety analysis, we 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 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 and chromium from 80

in one million (50 in one million using the lower end of the nickel 

URE range) to 5 in one million for actual emissions. The cancer 

incidence will be reduced from 0.002 to 0.0004, and the number of 

people estimated to have cancer risks greater than one in one million 

will be reduced, from 26,000 people to 1,300 people. The chronic 

noncancer inhalation TOSHI will be reduced from 90 to 2, and the 

number of people exposed to a TOSHI level greater than 1 will be 

reduced from 28,000 people to less than 10 people. In addition, the 

maximum acute HQ value will be reduced from potentially up to 10 to 

less than 1, and 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 costeffective controls beyond those proposed above. As a result, we 

conclude that the implementation of theis proposed requirements 
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described above rule will provide public health protection with an 

ample margin of safety.

Nevertheless, we are soliciting comments and information 

regarding additional dust and process fugitive control measures and ,

work practices that may be available and their feasibility to further 

reduce process and dust fugitive emissions of metal HAP, or 

additional monitoring that may be warranted to ensure adequate 

control of process fugitive emissions. We also request comments on 

the costs and effectiveness of achieving the proposed process 

fugitive control measures and any additional options that may be 

suggested. 

We also note that we are soliciting comment on our unacceptable 

risk finding. If we conclude, after evaluating data and information 

received in comments on this proposed rule, that the risks posed by 

this source category are acceptable, then based on the data and 

information we currently have, we would likely propose adopt the same 

controls described in section IV.C.2 as being necessary to provide an 

ample margin of safety. As noted above in this section and in section 

IV.C.2.c., the proposed controls provide significant risk reductions 

beyond the current rule. Furthermore, as discussed more extensively 

in section IV.D.2 of this notice, below, we conclude that the 

emission reductions associated with these controls are cost effective 

and technically feasible. We solicit comment on the appropriateness 

of these controls in the event we find, based on data and information 
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received in comment, that the current rule provides an acceptable 

risk.

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

technology review?

Based on our technology review, we determined that there have 

been advances in emissions control measures since the Ferroalloys 

Production NESHAP was originally promulgated in 1999. Since 

promulgation, facilities have steadily improved the performance of 

their control devices through upgrades or replacements. They have 

also developed improved capture techniques for some process fugitives 

(e.g., casting and tapping emissions). Additional details regarding 

these analyses can be found in the following technical document for 

this action which is available in the docket: Draft Technology Review 

for the Ferroalloys Production Source Category.

1. Metal HAP emissions from stacks

We propose to continue to use particulate matter as a surrogate 

for metal HAP other than mercury. For a discussion regarding the 

appropriateness of particulate matter as a surrogate for non-mercury 

metal HAP, please see the metal HAP surrogacy memo ―Surrogate for 

Metal HAP Emissions for the Ferroalloys Source Category‖ in the 

docket for this proposed rule. Based on the results from the ICR test 

program, we determined that all of the sources of stack emissions are 

emitting at significantly lower levels than their maximum permitted 

levels. For this reason, under the authority of CAA section 
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112(d)(6), we are proposing revised emission limits for new and 

existing sources. We are also proposing that any uncontrolled furnace 

vent stacks would be subject to the same concentration limits. 

We calculated the proposed emission limits based on a MACT floor 

UPL analysis, resulting in a proposed existing source furnace stack 

emissions limit of 24 mg/dscm and proposed new source furnace stack 

emissions limit of 9.3 mg/dscm. We also calculated a proposed stack 

emission limit of 13 mg/dscm for crushing and screening equipment 

that would apply to both new and existing sources. 

The metal oxygen refining operation is a unique process, and so 

we only have a single ICR test data point. Therefore, we calculated a 

proposed emissions limit for this source using the 99 percent UPL 

from the test data, resulting in a proposed limit of 1.53.9 mg/dscm 

that would apply to new and existing metal oxygen refining operation 

sources. We request comment on whether we should instead set the MOR 

limit to be the same as the proposed furnace stack limit for existing 

sources. This change would allow a facility to use any excess 

capacity in the MOR control device to treat furnace emissions, if 

needed. Such a limit is still more stringent than the current limit 

included in subpart XXX for the MOR (approximately 69 mg/dscm).

Based on our analyses, we expect that no additional controls 

would be required for the facilities to comply with these proposed 

limits. To demonstrate compliance, Wwe propose that sources would be 

required to conduct periodic performance testing, and develop and 
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operate according to a baghouse operating plan or continuously 

monitor scrubber operating parameters. Furnace baghouses would be 

required to be equipped with bag leak detection systems (BLDS).

2. Metal HAP emissions from process fugitives

As described above, we evaluated several options to improve and 

increase the capture and control of process fugitive sources. The two 

main options involve either local ventilation or building 

ventilation. Local ventilation (e.g., hoods or ductwork located in 

close proximity to an emissions source such as tapping or casting) is 

common in this industry, but performance varies due to design of the 

capture system, maintenance practices and control device capacity. 

Industry representatives have expressed concern that extensive 

retrofitting of local ventilation is complicated at existing 

facilities because of the need for material movement using large 

overhead cranes and ladles. We identified a furnace building 

ventilation system at a ferrosilicon producer, using a similar 

production process. This ―system‖ is basically an enclosure of the 

furnace building with evacuation of emission to a control device.

We evaluated an option to enclose the furnace building(s) and 

evacuate the emissions to a control device(s) similar to the system 

used at the ferrosilicon producing facility described above. Based on 

that evaluation, we believe that it is feasible to install enclosures 

and have the fugitive emissions at the ridge vents of the shop 

building collected under negative pressure and ducted to a control 
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device, and have a PM emissions limit at the control device the same 

as it is for the furnace stacks (i.e., 24 mg/dscm). This would allow 

sources the option to duct some or all process fugitive emissions to 

an existing furnace control device if it has excess capacity. If it 

does not have excess capacity, the facility would have to install 

additional controls. Under this option, the source would also have to 

monitor building opacity; prepare and operate according to a process 

fugitives emissions ventilation plan, which would include 

requirements to demonstrate that the building is being operated at a 

negative pressure of at least 0.007 inches of water; and conduct 

periodic performance testing of the building ventilation control 

device to demonstrate compliance with the proposed standards. 

Baghouses would be required to be equipped with BLDS.

We estimate the total capital costs of installing the required 

ductwork, fans, and baghouses under this option to be $9.45 million 

and the total annualized costs to be $2.3 million for the two plants. 

We estimate that particulate metal HAP emissions would be reduced by

81 tons, resulting in a cost per ton of HAP removed at $28,000 per 

ton ($14 per pound). We also estimate that this option would achieve

PM emission reductions of 630 tons, resulting in a cost per ton of PM 

removed at $3,600 per ton and achieve PM2.5 emission reductions of 

257315 tons, resulting in a cost per ton of PM2.5 removed of $78,8200

per ton. In light of the technical feasibility and cost effectiveness 

of this approach, we are proposing this option under the authority of 
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section 112(d)(6). These proposed requirements are exactly the same 

as those proposed under Section 112(f) which are described in section 

IV.C.2 of this preamble.

As described above in section IV.C.2.b, we are also proposing an 

equivalent alternative compliance approach. Facilities can design and 

implement an equivalent alternative approach (e.g., local capture, 

controls, and work practices) to achieve equivalent emissions 

reductions of those their process fugitive emissions. Compliance 

would be demonstrated by ensuring facilities apply the equivalent 

alternative approach to control process fugitive emissions, continue 

the work practices to minimize outdoor fugitive dust emissions, and 

also conduct fenceline monitoring to demonstrate that the ambient 

concentration of manganese at their facility boundary is no more than 

0.1 μg/m3 on a 60-day rolling average. We acknowledge that there may 

be other control measures and alternative approaches that we have not 

identified that are effective in reducing process fugitive emissions 

from the furnace building. Therefore, as an alternative to the 

requirement to enclose the furnace building(s) and evacuate the 

emissions to a control device(s), we are proposing a fenceline action 

level that would serve as a trigger for corrective action should such 

level be exceeded. This monitoring alternative is designed to allow 

for flexibility and prevent redundant requirements.

Specifically, we propose to require that sources seeking to use

this alternative prepare and submit for the Administrator‘s approval 
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a written plan describing and explaining a proposed compliance 

monitoring network to consist of at least two monitors and procedures 

for sampling, sample handling and custody, sample analysis, quality 

assurance, and recordkeeping procedures. The purpose of the ambient 

air monitoring network would be to ensure that manganese 

concentrations in air near the facility boundaries remain at or below 

0.1 μg/m3 based on 10-sample rolling averages, with samples being 

collected every 6 days. The monitoring plan must include a minimum of 

two monitoring sites that are placed in locations that are most 

likely to capture measurements of the maximum concentrations at or 

near the facility boundaries. For example, at least one monitor must 

be placed in the predominant downwind direction from main emissions 

sources based on historical weather patterns in the area. This 

alternative regulatory requirement would provide flexibility to 

facilities in determining the within-facility sources that should be 

vented to a control device that are most effective for reducing 

process fugitive emissions at their facilities. Nevertheless, we are 

seeking comments on this proposed alternative requirement, including 

whether two monitors would be sufficient or if more monitors may be 

warranted.

We propose that if the 10-sample rolling averages exceed the 

specified concentration then corrective actions must be implemented. 

Upon the first exceedance of a 10-sample rolling average, the source 

would be required within 6 months to evaluate the capture and control 
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of process fugitives from the furnace building, and evaluate other 

potential sources of fugitive emissions, and then implement any 

changes indicated to reduce fugitive emissions to levels that would 

result in air levels below 0.1 μg/ m

3 based on 10-sample rolling 

averages. Upon a next exceedance of the 10-sample rolling average 

following the 6-month implementation period, the source would be 

required to comply with the requirement to enclose the furnace 

building(s) and evacuate the emissions to a control device(s). In 

this case, the source would be required to complete the enclosure 

within 1 year from the time the next exceedance occurs.

In order to avoid delays in complying with process fugitives 

standards, we propose to require that the written plan be submitted 

within 45 days of the effective date of the final rule so that all 

necessary planning, equipment acquisition and system development can 

take place before the 2-year compliance date. In this way, if the 

source determines that the use of such system is unlikely to be an 

effective alternative to the building enclosure option, the source 

would be able to comply with the primary option by the compliance 

date of the proposed standards.

We propose to base the fenceline concentration action level to 

reflect the comparable level of risk that is estimated to remain 

after compliance with the requirement to enclose the furnace 

building(s) and evacuate the emissions to a control device(s). As 

described in section IV.D.2, the maximum chronic noncancer inhalation 
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TOSHI value would be 2, because the post-control modeling indicates 

the maximum ambient concentration of manganese would be twice the 

current value of the RfC for manganese. Therefore, a value twice this 

concentration, 0.1 μg/m3, is proposed as the fenceline action level. 

We request comment on whether the action level should instead be 

based on the actual RfC of 0.05 μg/m3 to ensure that variations in 

manganese emissions over a 10-sample period will remain at acceptable 

levels. We note that the RfC is not designed to be a regulatory 

limit, and it is defined as ―An estimate (with uncertainty spanning 

perhaps an order of magnitude) of a continuous inhalation exposure to 

the human population (including sensitive subgroups) that is likely 

to be without an appreciable risk of deleterious effects during a 

lifetime. It can be derived from a NOAEL, LOAEL, or benchmark 

concentration, with uncertainty factors generally applied to reflect 

limitations of the data used.‖39 Therefore, we request comment on 

other concentration values that might be appropriate to monitor under 

this fenceline alternative. The proposed averaging period is 

consistent with the School Air Toxics Initiative ambient air 

monitoring program, but we request comment on whether a different 

averaging period should be required.

As part of this alternative, we are also proposing a provision 

that would allow for reduced monitoring if the facility demonstrates 

ambient manganese concentrations less than 50 percent of the ambient 

 

39 IRIS Glossary. http://www.epa.gov/iris/help_gloss.htm.
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manganese concentration limit for 3 consecutive years at each 

monitor. We propose that a revised monitoring plan may be submitted 

(for review and possible approval by the Administrator) to reduce the 

sampling and analysis frequency if all of the 10-sample rolling 

average concentrations at each monitor are less than 50 percent of 

the limit of 0.1 μg/m3 over a 3-year period. 

3. Hydrochloric acid, hydrofluoric acid and formaldehyde, mercury and 

PAH emissions from furnace stacks

The controls for HCl, formaldehyde, mercury and PAHs were 

described in Section IV.A., and no additional controls have been 

identified.No facilities in the source category use add-on control 

devices or work practices to limit emissions of these pollutants 

beyond what is normally achieved as co-control of the emissions with 

particulate matter control device. There are available add-on control 

devices, such as lime injection, but their use is not indicated given 

the costs of installing and operating such controls and a concern 

that use of this control technology could prevent the current 

practice of reusing or selling baghouse dust and the resulting waste 

reduction benefits. See the Draft MACT Floor Analysis for the 

Ferroalloys Production Source Category in the docket for more 

discussion of this topic.

For this reason, we are not proposing any additional 

requirements for HCl , FH, or formaldehyde under CAA section 

112(d)(6).
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4. Mercury emissions from furnace stacks

As described in section IV.A of today‘s preamble, we are 

proposing MACT limits for mercury based a beyond the floor analysis. 

In this section we provide further discussion of the review of the 

relevant technologies.

No facilities in the source category use add-on control devices 

or use work practices to limit emissions of mercury emissions beyond 

what is normally achieved as co-control of the emissions with the 

particulate matter control device. We found that the bulk of mercury 

emissions are emitted from the furnace control devices as measured 

during the ICR test program. Because of the magnitude of mercury 

emissions (estimated to be 540 pounds per year (lb/yr) at one plant 

and 140 lb/yr at the other plant), we evaluated potential add-on 

control in the form of activated carbon injection. 

The use of activated carbon injection is being considered in 

other recent NESHAP such as the Utility MACT NESHAP and the Portland 

Cement NESHAP, and mercury reductions of up to 90 percent should be 

achievable at ferroalloys production facilities. Based on our 

experience with mercury controls for other combustion sources such as 

boilers, we conclude that activated carbon injection is a viable 

control technology in the Ferroalloys Production source category, but 

we request comment on other possible controls that could be effective 

and perhaps less costly. We recognize the potential concern that use 

of these controls upstream of the particulate matter control device 
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may pose issues with fabric filter dust contamination or sludge 

contamination and may result in some waste products being classified 

as Resource Conservation and Recovery Act (RCRA) waste versus the 

more easily and less costly to dispose of industrial waste. In 

addition, some companies re-use or sell their baghouse dust 

(primarily for use in cement kilns). There is concern that even if 

the material meets quality standards, that re-introduction of the 

dust into a furnace or kiln wcould cause the mercury to become 

unbound from the carbon and be emitted into the atmosphere. 

We reviewed facility specific control options that included 

putting the mercury controls downstream of the existing furnace 

baghouse to avoid the potential issues associated with upstream 

controls. Under this scenario, the activated carbon injection system 

would be followed by a ―polishing‖ baghouse to capture the activated 

carbon for disposal. In the case of the existing furnace scrubber, we 

assumed the source could put the activated carbon injection system 

upstream of the scrubber, the carbon would be captured by the 

scrubber and the resulting sludge treated according to the existing 

treatment process at the plant. Based on discussion with vendors and 

other control technology experts, we do not believe that the 

resulting carbon waste in either scenario would trigger the RCRA 

compliance concerns raised by the companies. This is because once the 

mercury absorbs to the activated carbon, it will stay there until 

heated above 400 degrees Fahrenheit. The captured activated carbon 
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should pass the Toxicity Characteristic Leaching Procedure test, 

which is an EPA test method used to characterize waste as either 

hazardous or non-hazardous for the purpose of disposal. Therefore, 

the captured activated carbon would unlikely be considered hazardous 

waste and can be disposed of in a landfill.

It might would be technically feasible to install controls at 

the remaining source to achieve even further reductions. However 

these reductions would be based on a much lower level of emissions 

and require installing the activated carbon injection systems 

upstream of three positive pressure baghouses, which would mean that 

they would not be able to reuse or sell any of their baghouse dust. 

We do not consider this to be a viable option at this time.

The option that we are proposing under section 112(d)(3), which 

is described in section IV.A. of this preamble, requires an estimated 

$1.7 million in capital costs, $1.4 million in annualized costs, with 

cost effectiveness of $3,300 per pound of mercury reduction. We 

concludebelieve this option reflects feasible and cost-effective 

controls. For this reason, under the authority of CAA section 

112(d)(6), we are also proposing to establish emission limits for 

mercury emissions at the beyond the floor level of 16 μg/dscm at 2 

percent CO2, which is the exact same standard that we are proposing 

under section 112(d)(2) and 112(d)(3) of the CAA, as described in 

section IV.A. of today‘s preamble.
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Both sources would be subject to periodic performance testing 

and periodic sampling of the manganese ore for variations in mercury 

content. Should the resulting weighted average mercury content 

increase significantly, the source would be required to retest in 

order to demonstrate continuing compliance. 

For this proposal, we propose that the determination of a 

significant increase in mercury content would be that the rolling

weighted average mercury concentration in the manganese ore increases

by 10 percent or more compared to the baseline weighted average 

mercury concentration. If that limit is exceeded, the source would be 

required to readjust the carbon injection rate as specified in the 

source‘s monitoring plan or retest within 30 days if there is not a 

dedicated mercury control device. If a new ore is added, sampling 

would be required as well. 

We are interested in any data that would show the variability in 

mercury concentration between different ore samples from the same 

location and the variability of the types of ores used in manganese 

production. If ore type and mercury content are demonstrated to be 

stable, we might consider whether to reduce the frequency of 

sampling/calculations to quarterly or less. 

Finally, any source installing activated carbon injection would 

be required to continuously monitor the carbon injection rate into 

the airstream being controlled. We request comment on the level of 
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variability in the carbon injection rate that should be allowed, and 

what percent decrease in the rate should be considered significant. 

5. Polycyclic aromatic hydrocarbons from the furnace stack

Like mercury, no existing facilities in the source category 

control PAH or use work practices to limit emissions of PAH emissions 

beyond what is normally achieved by modest co-control of the 

emissions with the particulate matter control device. Under today‘s 

proposal, these pollutants would be controlled with the same 

activated carbon injection technology as mercury. Because of this, 

emission reductions could be achieved via co-control at no additional 

costs. 

As described in section IV.A. of this preamble, the MACT floor 

for POM is based on an UPL that we believe both facilities can meet

with existing controls. Using the data from the higher emitting 

facility, we calculated a beyond the floor emissions level based on a 

90 percent reduction of the 99 percent UPL for PAH from this plant. 

The resulting limit is 89 μg/dscm. With a limit of 89 μg/dscm we 

estimate that the lower emitting facility would be able to meet this 

limit with no additional controls. We estimate that the higher 

emitting facility will be able to achieve this limit using activated 

carbon injection, which is the same controls we expect they would use 

to meet the mercury limit. Therefore, there would be no additional 

control costs to meet the limit for PAHs. As described in section 

IV.A. of this preamble, we are proposing a this limit of 89 μg/dscm 
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for PAHs under section 112(d)(3) of the CAA based on the beyond the 

floor analysis. No additional cost-effective controls have been 

identified for PAHs beyond those described in Section IV.A. of this 

preamble. We are also proposing the exact same limit under section 

112(d)(6) of the CAA since it reflects feasible and cost-effective

control technologies.

46. Outdoor fugitive dust emissions

The existing rule has a requirement for an outdoor fugitive dust 

control plan. We are unable to quantify HAP emissions from outdoor 

fugitive dust sources and did not identify any additional procedures 

or controls that could be expected to have a significant impact on 

these emissions. Therefore, we are not proposing to change the 

existing requirements.

E. What other actions are we proposing? 

1. Startup, Shutdown, Malfunction

The United States Court of Appeals for the District of Columbia 

Circuit vacated portions of two provisions in the EPA‘s CAA section 

112 regulations governing the emissions of HAP during periods of SSM. 

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

S. Ct. 1735 (U.S. 2010). Specifically, the Court vacated the SSM 

exemption contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), that 

are part of a regulation, commonly referred to as the ―General 

Provisions Rule,‖ that the EPA promulgated under CAA section 112. 

When incorporated into CAA section 112(d) regulations for specific 
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source categories, these two provisions exempt sources from the 

requirement to comply with the otherwise applicable CAA section 

112(d) emissions standard during periods of SSM.

We are proposing the elimination of the SSM exemption in this 

rule. Consistent with Sierra Club v. EPA, the EPA is proposing 

standards in this rule that apply at all times. We are also proposing 

several revisions to Table 1 to subpart XXX of part 63 (the General 

Provisions Applicability table). For example, we are proposing to 

eliminate the incorporation of the General Provisions‘ requirement 

that the source develop an SSM plan. We also are proposing to 

eliminate or revise certain recordkeeping and reporting that related 

to the SSM exemption. The EPA has attempted to ensure that we have 

not included in the proposed regulatory language any provisions that 

are inappropriate, unnecessary, or redundant in the absence of the 

SSM exemption. We are specifically seeking comment on whether there 

are any such provisions that we have inadvertently incorporated or 

overlooked. 

In proposing the standards in this rule, the EPA has taken into 

account startup and shutdown periods and, for the reasons explained 

below, has not proposed different standards for those periods.

Information on periods of startup and shutdown received from the 

industry in the ICR indicate that emissions during these periods do 

not increase. Control devices such as baghouses for metal HAP 

particulate control and activated carbon controls for mercury are 
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started up before the process units, and are operational during the 

shutdown phase of a process. Therefore, no increase in emissions is 

expected during these periods. Building ventilation systems for 

process fugitive emissions will be in place at all times. Therefore, 

separate standards for periods of startup and shutdown are not being 

proposed.

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). The EPA has determined 

that CAA section 112 does not require that emissions that occur 

during periods of malfunction be factored into development of CAA 

section 112 standards. Under CAA section 112, emissions standards for 

new sources must be no less stringent than the level ―achieved‖ by 

the best controlled similar source, and emission standards for 

existing sources generally must be no less stringent than the average 

emissions limitation ―achieved‖ by the best performing 12 percent (or 

5 sources in cases where there are fewer than 30 sources in the 

source category) of sources in the category. There is nothing in CAA 

section 112 that directs the Agency to consider malfunctions in 

determining the level ―achieved‖ by the best performing or best 

controlled sources when setting emissions standards. Moreover, while 
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the EPA accounts for variability in setting emissions standards 

consistent with the CAA section 112 case law, nothing in that case 

law requires the Agency to consider malfunctions as part of that 

analysis. Section 112 of the CAA uses the concept of ―best 

controlled‖ and ―best performing‖ unit in defining the level of 

stringency that CAA section 112 performance standards must meet.

Applying the concept of ―best controlled‖ or ―best performing‖ to a 

unit that is malfunctioning presents significant difficulties, as 

malfunctions are sudden and unexpected events.

Further, accounting for malfunctions would be difficult, if not 

impossible, given the myriad different types of malfunctions that can 

occur across all sources in the category and given the difficulties 

associated with predicting or accounting for the 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 certain point, the
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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, the 

goal of a best controlled or best performing source is to operate in 

such a way as to avoid malfunctions of the source and accounting for 

malfunctions could lead to standards that are significantly less 

stringent than levels that are achieved by a well-performing nonmalfunctioning source. The EPA‘s approach to malfunctions is 

consistent with CAA section 112 and is a reasonable interpretation of 

the statute. 

In the event that a source fails to comply with the applicable 

CAA section 112(d) standards as a result of a malfunction event, the 

EPA would determine an appropriate response based on, among other 

things, the good faith efforts of the source to minimize emissions 

during malfunction periods, including preventative and corrective 

actions, as well as root cause analyses to ascertain and rectify 

excess emissions. The EPA would also consider whether the source's 

failure to comply with the CAA section 112(d) standard was, in fact, 

―sudden, infrequent, not reasonably preventable‖ and was not instead 

―caused in part by poor maintenance or careless operation‖ 40 CFR

63.2 (definition of malfunction).
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Finally, the EPA recognizes that even equipment that is properly 

designed and maintained can sometimes fail and that such failure can 

sometimes cause an exceedance of the relevant emissions standard.

(See, e.g., State Implementation Plans: Policy Regarding Excessive 

Emissions During Malfunctions, Startup, and Shutdown (Sept. 20, 

1999); Policy on Excess Emissions During Startup, Shutdown, 

Maintenance, and Malfunctions (Feb. 15, 1983)). The EPA is therefore 

proposing to add to the final rule an affirmative defense to civil 

penalties for exceedances of emissions limits that are caused by 

malfunctions. See 40 CFR 63.1622 (defining ―affirmative defense‖ to 

mean, in the context of an enforcement proceeding, a response or 

defense put forward by a defendant, regarding which the defendant has 

the burden of proof, and the merits of which are independently and 

objectively evaluated in a judicial or administrative proceeding). We 

also are proposing other regulatory provisions to specify the 

elements that are necessary to establish this affirmative defense; 

the source must prove by a preponderance of the evidence that it has 

met all of the elements set forth in 40 CFR 63.1627 (40 CFR 22.24).

The criteria ensure that the affirmative defense is available only 

where the event that causes an exceedance of the emissions limit 

meets the narrow definition of malfunction in 40 CFR 63.2 (sudden, 

infrequent, not reasonable preventable and not caused by poor 

maintenance and or careless operation). For example, to successfully 

assert the affirmative defense, the source must prove by a 
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preponderance of the evidence that excess emissions ―[w]ere caused by 

a sudden, infrequent, and unavoidable failure of air pollution 

control and monitoring equipment, process equipment, or a process to 

operate in a normal or usual manner....‖ The criteria also are designed 

to ensure that steps are taken to correct the malfunction, to 

minimize emissions in accordance with 40 CFR 63.1623(g) and to 

prevent future malfunctions. For example, the source must prove by a 

preponderance of the evidence that ―[r]epairs were made as 

expeditiously as possible when the applicable emissions limitations 

were being exceeded...‖ and that ―[a]ll possible steps were taken to 

minimize the impact of the excess emissions on ambient air quality, 

the environment and human health....‖ In any judicial or administrative

proceeding, the Administrator may challenge the assertion of the 

affirmative defense and, if the respondent has not met its burden of 

proving all of the requirements in the affirmative defense, 

appropriate penalties may be assessed in accordance with CAA section

113 (see also 40 CFR 22.277).

The EPA included an affirmative defense in the proposed rule in 

an attempt to balance a tension, inherent in many types of air 

regulation, to ensure adequate compliance while simultaneously 

recognizing that despite the most diligent of efforts, emission 

limits may be exceeded under circumstances beyond the control of the 

source. The EPA must establish emission standards that ―limit the 

quantity, rate, or concentration of emissions of air pollutants on a 
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continuous basis.‖ 42 U.S.C. § 7602(k) (defining ―emission limitation 

and emission standard‖). See generally Sierra Club v. EPA, 551 F.3d 

1019, 1021 (D.C. Cir. 2008) Thus, the EPA is required to ensure that 

section 112 emissions limitations are continuous. The affirmative 

defense for malfunction events meets this requirement by ensuring 

that even where there is a malfunction, the emission limitation is 

still enforceable through injunctive relief. While ―continuous‖ 

limitations, on the one hand, are required, there is also caselaw 

indicating that in many situations it is appropriate for the EPA to 

account for the practical realities of technology. For example, in 

Essex Chemical v. Ruckelshaus, 486 F.2d 427, 433 (D.C. Cir. 1973), 

the D.C. Circuit acknowledged that in setting standards under CAA 

section 111 ―variant provisions‖ such as provisions allowing for 

upsets during startup, shutdown and equipment malfunction ―appear 

necessary to preserve the reasonableness of the standards as a whole 

and that the record does not support the  ̳never to be exceeded‘ 

standard currently in force.‖ See also, Portland Cement Association 

v. Ruckelshaus, 486 F.2d 375 (D.C. Cir. 1973). Though intervening 

caselaw such as Sierra Club v. EPA and the CAA 1977 amendments 

undermine the relevance of these cases today, they support the EPA‘s 

view that a system that incorporates some level of flexibility is 

reasonable. The affirmative defense simply provides for a defense to 

civil penalties for excess emissions that are proven to be beyond the 

control of the source. By incorporating an affirmative defense, the 
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EPA has formalized its approach to upset events. In a Clean Water Act 

setting, the Ninth Circuit required this type of formalized approach 

when regulating ―upsets beyond the control of the permit holder.‖ 

Marathon Oil Co. v. EPA, 564 F.2d 1253, 1272-73 (9th Cir. 1977). But 

see, Weyerhaeuser Co. v. Costle, 590 F.2d 1011, 1057-58 (D.C. Cir. 

1978) (holding that an informal approach is adequate). The 

affirmative defense provisions give the EPA the flexibility to both 

ensure that its emission limitations are ―continuous‖ as required by 

42 U.S.C. § 7602(k), and account for unplanned upsets and thus 

support the reasonableness of the standard as a whole.

Specifically, we are proposing the following changes to the 

rule.

Added general duty requirements in 40 CFR 63.1623(g) to replace 

General Provision requirements that reference vacated SSM 

provisions. 

Added replacement language that eliminates the reference to SSM 

exemptions applicable to performance tests in 40 CFR 63.1625(a)(5).

Added paragraphs in 40 CFR 63.1629(d) requiring the reporting of 

malfunctions as part of the affirmative defense provisions.

Added paragraphs in 40 CFR 63.1629(b) requiring the keeping of 

certain records during malfunctions as part of the affirmative 

defense provisions.

Developed Table 1 to subpart XXX of part 63 to reflect changes in 

the applicability of the General Provisions to this subpart 
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resulting from a court vacatur of certain SSM requirements in the 

General Provisions. 

2. Electronic reporting

The EPA and other authorities such as state, local and tribal 

agencies must have performance test data to conduct effective reviews 

of CAA sections 112 and 129 standards, as well as for many other 

purposes including compliance determinations, emission factor 

development, and annual emission rate determinations. We believe that 

improvements in the process of submitting, reviewing and storing test 

data would result in increases in efficiency and cost savings to the 

regulated community; state, local and tribal agencies; the public and 

ourselves. These improvements are possible because stack testing 

firms are increasingly collecting performance test data in electronic 

format, making it possible to move to an electronic data submittal 

system that would increase the ease and efficiency of data submittal 

and improve data accessibility.

Through this proposal, the EPA is proposing a step to increase 

the ease and efficiency of data submittal and improve data 

accessibility. Specifically, the EPA is proposing that owners and 

operators of Ferroalloys Production facilities submit electronic 

copies of required performance test reports to the EPA‘s WebFIRE 

database. The WebFIRE database was constructed to store performance

test data for use in developing emission factors. A description of 
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the WebFIRE database is available at 

http://cfpub.epa.gov/oarweb/index.cfm?action=fire.main. 

As proposed above, data entry would be through an electronic 

emissions test report structure called the Electronic Reporting Tool 

(ERT). The ERT would be able to transmit the electronic report 

through the EPA‘s Central Data Exchange network for storage in the 

WebFIRE database, making submittal of data very straightforward and 

easy. A description of the ERT can be found at 

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

The proposal to submit performance test data electronically to 

the EPA would apply only to those performance tests conducted using 

test methods that will be supported by the ERT. The ERT contains a 

specific electronic data entry form for most of the commonly used the 

EPA reference methods. A listing of the pollutants and test methods 

supported by the ERT is available at 

http://www.epa.gov/ttn/chief/ert/index.html. We believe that industry 

would benefit from this proposed approach to electronic data 

submittal. Having these data, the EPA would be able to develop 

improved emission factors, make fewer information requests, and 

promulgate better regulations. 

One major advantage of the proposed submittal of performance

test data through the ERT is a standardized method to compile and 

store much of the documentation required to be reported by this rule. 

Another advantage is that the ERT clearly states what testing 
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information would be required. Another important proposed benefit of 

submitting these data to the EPA at the time the source test is 

conducted is that it should substantially reduce the effort involved 

in data collection activities in the future. When the EPA has

performance test data in hand, there will likely be fewer or less 

substantial data collection requests in conjunction with prospective 

required residual risk assessments or technology reviews. This would 

result in a reduced burden on both affected facilities (in terms of 

reduced manpower to respond to data collection requests) and the EPA 

(in terms of preparing and distributing data collection requests and 

assessing the results).

State, local, and tribal agencies could also benefit from more 

streamlined and accurate review of electronic data submitted to them.

The ERT would allow for an electronic review process rather than a 

manual data assessment making review and evaluation of the source 

provided data and calculations easier and more efficient. Finally, 

another benefit of the proposed data submittal to WebFIRE 

electronically is that these data would greatly improve the overall 

quality of existing and new emissions factors by supplementing the 

pool of emissions test data for establishing emissions factors and by 

ensuring that the factors are more representative of current industry 

operational procedures. A common complaint heard from industry and 

regulators is that emission factors are outdated or not 

representative of a particular source category. With timely receipt
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and incorporation of data from most performance tests, the EPA would 

be able to ensure that emission factors, when updated, represent the 

most current range of operational practices. In summary, in addition 

to supporting regulation development, control strategy development, 

and other air pollution control activities, having an electronic 

database populated with performance test data would save industry, 

state, local, tribal agencies, and the EPA significant time, money,

and effort while also improving the quality of emission inventories 

and, as a result, air quality regulations.

3. Emissions Averaging

We are proposing to add an emissions averaging option for 

electric arc furnace stack emissions (PM, mercury, PAH, HCl, HF, or 

formaldehyde). We are also proposing to allow averaging between 

existing process fugitive control devices for PM stack emissions and 

between existing crushing and screening equipment for PM stack 

emissions. If you have more than one existing emission source (e.g., 

electric arc furnace) located at one or more contiguous properties, 

which are under common control of the same person (or persons under 

common control), you may demonstrate compliance by emission averaging 

among the existing emission sources, if your averaged emissions for 

such emission sources are equal to or less than the applicable 

emission limit.

We are also proposing to allow averaging between existing 

process fugitive control devices for PM stack emissions as a second 
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averaging group. However, we believe it may be appropriate to combine 

these process fugitive stack emissions into the furnace stack 

averaging group for PM emissions for two reasons. First, both types 

of emissions are likely to be controlled with similar, if not common 

control devices, e.g., large fabric filters. Second, we are proposing 

to apply an identical PM emission limit for both of these emission 

sources, which would simplify averaging of PM emissions. We request 

comment on this option.

We are also proposing to allow averaging between existing 

crushing and screening equipment for PM stack emissions. We believe 

this is a distinct averaging group compared to the furnace and 

process fugitives groups. The airflow and associated control devices 

are typically much smaller and they are subject to a more stringent 

emission limit than the other PM sources. However, we request comment 

on the potential for more broadly defined averaging options for this 

group.

As part of the EPA‘s general policy of encouraging the use of 

flexible compliance approaches where they can be properly monitored 

and enforced, we are including emissions averaging for existing 

sources in this proposed rule. Emissions averaging can provide 

sources the flexibility to comply in the least costly manner while

still maintaining regulation that is workable and enforceable. 

Emissions averaging would not be applicable to new affected sources.

Emissions averaging would allow owners and operators of an existing 
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affected source to demonstrate that the source complies with the 

proposed emission limits by averaging the emissions from an 

individual affected emission unit that is emitting above the proposed 

emission limits with other affected emission unit at the same 

facility that are emitting below the proposed emission limits and 

that are within the same averaging group, as described below.

This proposed rule includes an emissions averaging compliance

alternative because emissions averaging represents an equivalent, 

more flexible, and less costly alternative to controlling certain 

emission points to MACT levels. We have concluded that a limited form

of averaging could be implemented that would not lessen the 

stringency of the MACT limits and would provide flexibility in 

compliance, cost and energy savings to owners and operators of 

existing sources. We also recognize that we must ensure that any 

emissions averaging option can be implemented and enforced, will be

clear to sources, and most importantly, will be no less stringent 

than unit by unit implementation of the MACT limits.

The EPA is proposing has concluded that it is permissible to 

establish within a NESHAP a unified compliance regimen that permits 

averaging within an existing affected source across individual

affected units subject to the standard under certain conditions. 

Averaging across affected units is permitted only if it can be 

demonstrated that the total quantity of any regulated pollutant that 

may be emitted by that portion of a contiguous major source that is 
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subject to the NESHAP will not be greater under the averaging 

mechanism than it could be if each individual affected unit complied 

separately with the applicable standard. Under this test, the 

practical outcome of averaging is equivalent to compliance with the 

MACT limits by each discrete unit, and the statutory requirement that 

the MACT standard reflect the maximum achievable emissions reductions 

is, therefore, fully effectuated.

In past rulemakings, the EPA has generally imposed certain 

limits on the scope and nature of emissions averaging programs. These 

limits include: (1) no averaging between different types of

pollutants; (2) no averaging between sources that are not part of the 

same affected source; (3) no averaging between individual sources 

within a single major source if the individual sources are not 

subject to the same NESHAP; and (4) no averaging between existing 

sources and new sources. This proposed rule is consistent with these 

limitationswould fully satisfy each of these criteria. First, 

emissions averaging would only be permitted between individual 

sources at a single existing affected source, and would only be 

permitted between individual sources subject to the proposed 

Ferroalloys Production NESHAP. Further, emissions averaging would not 

be permitted between two or more different affected sources. Finally,

new affected sources could not use emissions averaging. Accordingly, 

we have concluded that the averaging of emissions across affected 

units is consistent with the CAA. 
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In addition, this proposed rule would require each facility that 

intends to utilize emission averaging to submit an emission averaging 

plan, which provides additional assurance that the necessary criteria 

will be met. In this emission averaging plan, the facility must 

include the identification of: (1) all units in the averaging group; 

(2) the control technology installed; (3) the process parameters that 

will be monitored; (4) the specific control technology or pollution 

prevention measure(s) to be used; (5) the test plan for the 

measurement of the HAP being averaged; and (6) the operating

parameters to be monitored for each control device. Upon receipt, the

regulatory authority would not be able to approve an emission 

averaging plan containing averaging between emissions of different 

types of pollutants or between different affected sources (e.g., 

between furnaces and crushing and screening equipment).

This proposed rule would also exclude new affected sources from 

the emissions averaging provision. The EPA believes emissions 

averaging is not appropriate for new affected sources because it is 

most cost effective to integrate state-of-the-art controls into

equipment design and to install the technology during construction of 

new sources. One reason we allow emissions averaging is to give 

existing sources flexibility to achieve compliance at diverse points 

with varying degrees of add-on control already in place in the most 

cost-effective and technically reasonable fashion. This flexibility 
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is not needed for new affected sources because they can be designed 

and constructed with compliance in mind.

In addition, wWe seek comment on use of a discount factor when 

emissions averaging is used and on the appropriate value of a 

discount factor, if used. Such discount factors (e.g., 10 percent) 

have been used in previous NESHAP, particularly where there was 

variation in the types of units within a common source category to 

ensure that the environmental benefit was being achieved. In this 

situation, however, the affected sources are more homogeneous, making 

emissions averaging a more straight forward analysis. Further, with

the monitoring and compliance provisions that are being proposed,

there is additional assurance that the environmental benefit will be 

realized. The emissions averaging provisions in this proposed rule 

are based in part on the emissions averaging provisions in the 

Hazardous Organic NESHAP (HON). The legal basis and rationale for the

HON emissions averaging provisions were provided in the preamble to 

the final HON.40 Consistent with the position we have explained in the 

HON and subsequent rulemakings that addressed averaging, we are not 

proposing emission averaging provisions for new sources.

43. Other Changes

The following lists additional minor changes to the NESHAP we 

are proposing. The main focus of these changes is to ensure that the 

rule provides adequate monitoring, reporting, recordkeeping and 

 

40 Hazardous Organic NESHAP (59 FR 19425; April 22, 1994).
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testing provisions to ensure that the affected sources are able to 

demonstrate continuous compliance with the proposed standards. These 

changes reflect changes we have made to many other existing NESHAP to 

improve the quality of these compliance requirements. This list also 

includes proposed rule changes that address editorial corrections and 

plain language revisions:

Reduce frequency of emission testing for the primary furnace 

control devices for PM and propose periodic testing for PM and 

other regulated pollutants. This change is possible because of 

requirement to conduct continuous monitoring. Also add a 

periodic testing requirement for the building ventilation system 

control devices and crushing and screening equipment control 

devices.

Add requirement for new and existing baghouses that control 

furnace or building ventilation systems to be equipped with BLDS

to demonstrate continuous compliance. Retain provisions for 

baghouses to have a baghouse SOP manual.

Add requirements to implement and enforce more detailed 

requirements for continuous parameter monitoring systems to 

ensure continuous compliance.

Reduce the shop building opacity limit to 10 percent opacity to 

reflect current industry performance. Eliminate 6-minute 

excursion level because it does not provide any significant 

flexibility (sources that tend to exceed the general opacity 

limit in any 6-minute period tend to do so for several minutes 

so that the excursions for one 6-minute period is meaningless). 

Eliminate events excluded from the opacity observation as they 

are infrequent, can be avoided in some cases, are emitted from 

operations we intend to control better, and can be confusing to 

enforce.

Change the format of the PM standards to reflect an outlet 

concentration format (mg/dscm). This format is the direct output 

of the emissions test and reflects the constant output nature of 

the predominant control device, i.e., a baghouse.

Add PM continuous emissions monitoring system as an alternative 

to installing and operating a BLDS.

Editorial cChanges, including revising the titles of sections in 

the subpart to better reflect the description of proposed 

requirements and to make the regulation easier for the reader to 

navigate.
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Update the recordkeeping and reporting sections to reflect the 

new monitoring requirements and monitoring options described 

above. 

Update the compliance dates to include the anticipated dates the 

proposed requirements will become effective.

F. What compliance dates are we proposing?

We are proposing that facilities must comply with the new 

proposed requirements in this action (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 

this rule. 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 §§63.1650 through 63.1661. 

Under 40 CFR 63.6(i)(4)(ii), ―the owner or operator of an 

existing source unable to comply with a relevant standard established 

...pursuant to section 112(f)...may request that the Administrator grant 

an extension allowing the source up to 2 years after the standard‘s 

effective date to comply with the standard.‖ The rule further 

specifies a written application for such a request. Here, the EPA is 

already fully aware of the steps needed for each source to comply 

with the proposed standards and to reasonably estimate the amount of 

time it will take each source to do so. We believe that the 2-year 

extension would be warranted in all cases for sources needing to 

upgrade current practice. This includes the time needed to: construct 

required building ventilation systems and install associated control 

devices for process fugitive sources; determine appropriate mercury 
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and PAH control devices, locations, amount and type of carbon needed 

and assess potential waste disposal issues; select and install 

appropriate monitoring technologies; seek bids, select a vendor, 

install and test the new equipment; and, purchase, install and 

conduct QA and quality control measures on compliance monitoring 

equipment (see Estimated Time Needed to Achieve Compliance with The 

Proposed Revisions to the MACT standard for Ferroalloys Production 

Facilities, which is available in the docket for this proposed 

action). The EPA believes it reasonable to interpret 40 CFR

63.6(i)(4)(ii) to allow this plenary finding, rather than utilizing a 

facility-by-facility application process, when the facts are already 

known and a category-wide adjudication is therefore possible. In 

addition, utilizing this process allows for public comment on the 

issue which would not be possible if a case-by-case application 

process with a 90-day window for completion were used.

V. Summary of Cost, Environmental, and Economic Impacts

A. What are the affected sources?

We anticipate that the two manganese production 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 facility that has a permit to produce 

ferromanganese or silicomanganese in an electric arc furnace, but it 

did so for only a brief period, several years ago. It is possible 
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that this facility could resume production or another non-manganese 

ferroalloy producer could decide to commence production of 

ferromanganese or silicomanganese. One of the existing facilities is 

considering building a new manganese furnace, but their timeline and 

actual intent to go forward is unclear. 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 estimated the emissions reductions that are expected to 

result from the proposed amendments to the 1999 NESHAP compared to 

the 2010 baseline emissions estimates. A detailed documentation of 

the analysis can be found in: Draft Cost Impacts of the Revised 

NESHAP for the Ferroalloys Production Source Category.

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 current proposal 

would cut HAP emissions (primarily particulate metal HAP such as 

manganese, arsenic and nickel) by 60 percent from their current 

levels. Under the proposed emissions limit for process fugitives 

emissions from the furnace building, we estimate that the HAP 

emissions reductions would be 81 tpyTPY, including significant 

reductions of manganese. We also anticipate mercury reductions of 420 

lb/yr and PAH reductions of 2.5 tpyTPY from installation of activated 
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carbon injection controls at one facility. Total HAP reductions for 

the two facilities are estimated to be 84 tpy.

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, HF, and formaldehyde without additional 

controls. There may be some formaldehyde emission reductions at the 

facility that we believe will be required to install an activated 

carbon injection system, but we have not quantified these reductions 

because of the uncertainty of the effectiveness of the activated 

carbon system designed for mercury and PAH removal compared to 

formaldehyde removal. We do not anticipate any reductions in HClthe 

acid gas pollutants.

C. What are the cost impacts?

Under the proposed amendments, ferroalloys production facilities 

are expected to incur capital costs for the installation of ductwork 

and baghouses for building ventilation and activated carbon injection 

systems. There would also be capital costs associated with installing 

new or improved continuous monitoring systems, included installation 

of BLDS on the furnace and building ventilation baghouses that are 

not currently equipped with these systems.

The capital costs for each facility were estimated based on the 

number and types of upgrades required. The memorandum Draft Cost 

Impacts of the Revised NESHAP for the Ferroalloys Production Source 
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Category includes a complete description of the cost estimate methods 

used for this analysis and is available in the docket.

The majority of the capital costs estimated for compliance with 

the amendments proposed in this action are for purchasing new control 

devices. For the shop building ventilation system, we assumed that 

each facility would need to install a building ventilation system in 

order to comply with the proposed shop building emissions limits. For 

each facility, we estimated the square footage of shop building air 

that would need to be evacuated and the size of control device that 

would be required. Although the proposed amendments would provide the 

alternative option to install monitors at or near the property 

boundary to demonstrate compliance with the building ventilation 

requirements, we assume that sources would be unlikely to meet the 

alternative standard without improving the level of control in the 

shop building.

To estimate the cost for the building ventilation fabric filter, 

we contacted a vendor who had recently supplied a fabric filter to 

one of the facilities to obtain assistance in developing a cost 

estimate for the installation. The equipment-only cost supplied by 

the vendor was used in conjunction with techniques described in the 

sixth edition of the EPA Air Pollution Control Cost Manual41 to 

estimate total installed capital cost and annual costs. 

 

41 http://epa.gov/ttn/catc/products.html#cccinfo.
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Our cost model included installation of the baghouse and any 

necessary fans, ductwork, and site work, including extra ductwork for 

connection to the building roof monitors. The total installed capital 

cost of three fabric filters (two at one facility, one at the second 

facility) designed for a flow-rate of 150,000 actual cubic feet per 

minute was estimated at $9.4 million. The annualized capital cost and 

operational and maintenance costs are estimated at $2.3 million, via 

techniques described in the sixth edition of the EPA Air Pollution 

Control Cost Manual. The annualized cost assumes a 20-year life 

expectancy for the unit and, to be consistent with OMB Guidance in 

Circular A-4, a 7 percent cost of capital as an estimate of the 

annualized capital cost.

We considered installation of both fixed carbon beds and 

activated carbon injections for the control of mercury and PAH

emissions. After talking to carbon vendors, we learned that fixed 

carbon beds are not a viable option given the size of the furnace 

airstream we would need to control. We also considered whether to put 

the activated carbon injection upstream or downstream of the existing 

PM control device. By installing the system downstream of the PM

control device, we would avoid potential concerns with the activated 

carbon interfering with potential sale or reuse of baghouse dust or 

potential increase in mercury load in the scrubber sludge 

impoundment. This approach requires installation of a separate 

―polishing‖ baghouse to capture the injected carbon for disposal. 
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Unlike activated carbon systems used primarily for control of 

volatile organic compounds, we have been told that mercury 

impregnated compounds cannot be recycled. There is concern that such 

downstream control could result in sufficient concentration of 

mercury in the baghouse dust that the facility would be required to 

treat such dust as a hazardous waste under the RCRA. However, based 

on conversations with vendors and other mercury control experts, we 

believe that the resulting waste will most likely be nonhazardous. We 

are seeking comments on the cost methodology and assumptions used to 

develop these cost estimates.

Costs for Activated Carbon Injection (ACI) were estimated using 

cost equations developed for the Utility NESHAP42. The calculated 

equipment costs for ACI and fabric filters were used in conjunction 

with techniques described in the sixth edition of the EPA Air 

Pollution Control Cost Manual to estimate total installed capital 

cost and annual costs. Our cost model included installation of the 

two ACI systems, one polishing fabric filter, and associated fans, 

ductwork, and site work. We estimate the total capital costs are $1.7

million and the annual costs are $1.4 million.

The estimated costs for the proposed change to the monitoring 

requirements for baghouses, including installation of seven new BLDS

for four existing furnace baghouses and three building ventilation 

baghouses is $270,000 of capital cost. The capital cost for a 

 

42 Sargent & Lundy, IPM Model - Revisions to Cost and Performance for APC 

Technologies, Mercury Control Cost Development Methodology Final, March, 2011. 

http://www.epa.gov/airmarkt/progsregs/epa-ipm/docs/append5_3.pdf.
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differential pressure monitor to ensure that shop buildings are under 

negative pressure is $9,200. The capital cost estimated for a 

continuous parameter monitoring system for the wet scrubber at one 

facility is estimated to be $50,000. Finally, the estimated capital 

cost for carbon injection monitoring is $20,000. The capital costs

for all additional monitoring and recordkeeping requirements, 

including the baghouse monitoring proposed, is estimated at $340,200.

Annualized costs are estimated to be $94,000 for the BLDS, 

$18,000 for the scrubber parameter monitoring system, and $6,200 for 

the carbon injection monitoring system. There is also an estimated 

annualized cost to monitor the manganese ore content for mercury 

emissions of $1,200. The estimated annual cost for reporting and 

recordkeeping is $37,000. We estimate the costs of the periodic 

performance testing requirements to be $800,000. The resulting total 

annualized costs are $347,000.

The total annualized costs for the proposed rule are estimated 

at $4.0 million (2010 dollars). Table 6 provides a summary of the 

estimated costs and emissions reductions associated with the proposed 

amendments to the Ferroalloys Production NESHAP presented in today‘s 

action.

Table 6. Estimated Costs and Reductions for the Proposed Standards in 

this Action

Proposed 

Amendment

Estimated 

Capital 

Cost 

($MM)1

Estimated 

Annual 

Cost 

($MM)

Total HAP 

Emissions 

Reductions 

(tpyTPY)

Cost 

Effectiveness 

in $ per ton 

total HAP 

reduction (and 

in $ per 
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pound)

Capture and 

Control 

Process 

Fugitives

9.4 2.3 81 (of 

metal HAP)

$0.03 MM per 

ton 

($14 per 

pound)

MACT Limits 

for Mercury 

1.7 1.4 0.2 (of 

mercury)

$6.7 MM per 

ton

($3,300 per 

pound)

MACT Limits 

for cocontrol of 

PAH

NA N/A 2.5(of 

PAH)

N/A

HCl, HF,

and formaldehyde 

concentration 

limits

0 0

0 N/A

Compliance 

testing 

over 3-year 

period

N/A 0.26 N/A N/A

Annual 

average 

monitoring

over 3-year 

period

0.11 0.08 N/A N/A

D. What are the economic impacts?

We estimate that there will be no more than a 0.2 percent price 

change and a similar reduction in output associated with the 

proposal. The impacts to affected firms will be low because the 

annual compliance costs are quite small when compared to the annual 

revenues for the two affected parent firms (much less than 1 percent 

for each). The impacts to affected consumers should also be quite 

small. Thus, there will not be any significant impacts on affected 

firms and their consumers as a result of this proposal.

E. What are the benefits?
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We estimate the monetized benefits of this regulatory action to 

be $710 million to $1780 million (2010$), at a 3 percent discount 

rate in the implementation year (2015). The monetized benefits of the 

regulatory action at a 7 percent discount rate are $630 million to 

$160 million (2010$) in the same implementation year. Using alternate 

relationships between PM2.5 and premature mortality supplied by 

experts, higher and lower benefits estimates are plausible, but most 

of the expert-based estimates fall between these two estimates.43 A 

summary of the monetized benefits estimates at discount rates of 3 

percent and 7 percent is in Table 7 of this preamble. 

Table 7. Summary of the Monetized Benefits Estimates for the 

Ferroalloys Industry in 2015 (millions of 2010$)

Pollutant

Estimated 

Emission 

Reductions

(tpy)

Total Monetized 

Benefits

(3% Discount Rate)

Total Monetized 

Benefits

(7% Discount Rate)

PM2.5 257 $710 to $1780 $630 to $160

1 All estimates are for the implementation year (―2015‖, assuming 

the final rule is published in January 2012) and are rounded to two 

significant figures so numbers may not sum across rows. All fine 

particles are assumed to have equivalent health effects. Benefits 

from reducing HAPs emissions are not included. 

These benefits estimates represent the total monetized human 

health benefits for populations exposed to less PM2.5 in 2015 from 

controls installed to reduce air pollutants in order to meet these 

proposed standards. These estimates are calculated as the sum of the 

monetized value of avoided premature mortality from reducing PM2.5. To 

estimate human health benefits derived from reducing PM2.5, we used 

 

43 Roman, et al., 2008. Expert Judgment Assessment of the Mortality Impact of 

Changes in Ambient Fine Particulate Matter in the U.S. Environ. Sci. Technol., 42, 

7, 2268 – 2274.
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the general approach and methodology laid out in Fann, Fulcher, and 

Hubbell (2009).44 However, iIn this proposal, we also includedutilized

source apportionment consideration based on current air quality 

modeling for the ferroalloys industry.45 Therefore all benefits per 

ton estimates are specific to the ferroalloys sector.

To generate the BPT estimates, we used a model to convert 

emissions of direct PM2.5 into changes in ambient PM2.5 levels and 

another model to estimate the changes in human health associated with 

that change in air quality. Finally, the monetized health benefits 

were divided by the emission reductions to create the BPT estimates. 

These models assume that all fine particles, regardless of their 

chemical composition, are equally potent in causing premature 

mortality because there is no clear scientific evidence that would 

support the development of differential effects estimates by particle 

type. In this rule only directly emitted PM2.5 is considered. Direct 

PM2.5 emissions convert directly into ambient PM2.5; thus, to the 

extent that emissions occur in population areas, exposures to direct 

PM2.5 will tend to be higher than exposure to any other precursor, and 

monetized health benefits will be higher as well. 

For context, it is important to note that the magnitude of the 

PM benefits is largely driven by the concentration response function 

 

44 Fann, N., C.M. Fulcher, B.J. Hubbell. 2009. ―The influence of location, source, 

and emission type in estimates of the human health benefits of reducing a ton of 

air pollution.‖ Air Qual Atmos Health (2009) 2:169–176.

45 U.S. Environmental Protection Agency. 2011. Technical support document: 

Estimating the benefit per ton of reducing PM2.5 precursors from the ferroalloy 

sector (Draft); EPA: Research Triangle Park, NC.
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for premature mortality. Experts have advised the EPA to consider a 

variety of assumptions, including estimates based on both empirical 

(epidemiological) studies and judgments elicited from scientific 

experts, to characterize the uncertainty in the relationship between 

PM2.5 concentrations and premature mortality. For this rule, we cite 

two key empirical studies, the American Cancer Society cohort study46

and the extended Six Cities cohort study.47 In the Regulatory Impact 

Analysis (RIA)

48 for this rule, we also include benefits estimates 

derived from expert judgments and other assumptions.

The EPA strives to use the best available science to support our 

benefits analyses. We recognize that interpretation of the science 

regarding air pollution and health is dynamic and evolving. After 

reviewing the scientific literature and recent scientific advice, we 

have determined that the no-threshold model is the most appropriate 

model for assessing the mortality benefits associated with reducing 

PM2.5 exposure. Consistent with this recent advice, we are replacing 

the previous threshold sensitivity analysis with a new ―Lowest 

Measured Level (LML)‖ assessment. While an LML assessment provides 

some insight into the level of uncertainty in the estimated PM 

mortality benefits, the EPA does not view the LML as a threshold and 

 

46 Pope et al, 2002. ―Lung Cancer, Cardiopulmonary Mortality, and Long-term 

Exposure to Fine Particulate Air Pollution.‖ Journal of the American Medical 

Association. 287:1132-1141.

47 Laden et al, 2006. ―Reduction in Fine Particulate Air Pollution and Mortality.‖ 

American Journal of Respiratory and Critical Care Medicine. 173: 667-672.

48 U.S. Environmental Protection Agency, 2006. Final Regulatory Impact Analysis: 

PM2.5 NAAQS. Prepared by Office of Air and Radiation. October. Available on the 

Internet at http://www.epa.gov/ttn/ecas/ria.html.
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continues to quantify PM-related mortality impacts using a full range 

of modeled air quality concentrations.

Most of the estimated PM-related benefits in this rule would 

accrue to populations exposed to higher levels of PM2.5. Using the 

Pope, et al., (2002) study, 895 percent of the population is exposed 

at or above the LML of 7.5 μg/m3. Using the Laden, et al., (2006) 

study, 3140 percent of the population is exposed above the LML of 10 

μg/m3. It is important to emphasize that we have high confidence in 

PM2.5-related effects down to the lowest LML of the major cohort 

studies. This fact is important, because as we estimate PM-related 

mortality among populations exposed to levels of PM2.5 that are 

successively lower, our confidence in the results diminishes. 

However, our analysis shows that the great majority of the impacts 

occur at higher exposures. 

This analysis does not include the type of detailed uncertainty 

assessment found in the 2006 PM2.5 NAAQS RIA because we lack the 

necessary air quality input and monitoring data to run the benefits 

model. In addition, we have not conducted any air quality modeling 

for this rule. However, to estimate BPT specifically for this sector 

we did have some updated air quality modeling. The 2006 PM2.5 NAAQS 

benefits analysis provides an indication of the sensitivity of our 

results to various assumptions.

It should be emphasized that the monetized benefits estimates 

provided above do not include benefits from several important benefit 
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categories, including reducing other air pollutants, ecosystem 

effects, and visibility impairment, as well as mercury and

formaldehyde among other HAPs. Although we do not have sufficient 

information or modeling available to provide monetized estimates for 

this rulemaking, we include a qualitative assessment of the health 

effects of these other effects in the RIA49 for this proposed rule.

F. What demographic groups might benefit the most from this 

regulation?

To examine the potential for any environmental justice (EJ) 

issues that might be associated with the source category, we 

performed a demographic analysis of the at-risk population. In this 

analysis, we evaluated the distributions of HAP-related cancer and 

noncancer risks from the Ferroalloys Production source category 

across different social, demographic and economic groups within the 

populations living near these two facilities. 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, 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. 

 

49 U.S. Environmental Protection Agency. Draft Regulatory Impact Analysis (RIA) for 

the Proposed Manganese Ferroalloys RTR. September 2011 
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TABLE 8. Ferroalloy Production Demographic Risk Analysis Results

Nationwide

Population with 

Cancer Risk at 

or Above 1-in-1 

Million

Population with 

Chronic Hazard 

Index Above 1

Total 

Population

285,000,000 26,000 28,000

Race by Percent

White 75 97 97

All Other 

Races 25 3 3

Race by Percent

White 75 97 97

African 

American 12 1 0.8

Native 

American 0.9 0.3 0.3

Other and 

Multiracial 12 2 1.8

Ethnicity by Percent

Hispanic 14 1 0.7

Non-Hispanic 86 99 99

Income by Percent

Below Poverty 

Level 13 13 13

Above Poverty 

Level 87 87 87

Education by Percent

Over 25 and 

without High 

School 

Diploma

13 11 9

Over 25 and 

with a High 

School 

Diploma

87 89 91

The results of the Ferroalloy Production source category 

demographic analysis indicate that there are approximately 26,000 

people exposed to a cancer risk at or above one in one million and 

approximately 28,000 people exposed to a chronic noncancer TOSHI 

greater than 1 due to emissions from the source category (we note 
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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 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 atrisk people due to HAP emissions from these sources (from 26,000 

people to about 1,000 for cancer risks and from 28,000 people to less 

than 10 for chronic noncancer TOSHI).

VI. Request for Comments

We are soliciting comments on all aspects of this proposed 

action. In addition to general comments on this proposed action, we 

are also interested in any additional data that may help to reduce 

the uncertainties inherent in the risk assessment and other analyses.

We are specifically interested in receiving corrections to the sitespecific emissions profiles used for risk modeling. Such data should 

include supporting documentation in sufficient detail to allow 

characterization of the quality and representativeness of the data or 

information. Section VII of this preamble provides more information 

on submitting data.

VII. Submitting Data Corrections

The site-specific emissions profiles used in the source category 

risk and demographic analyses are available for download on the RTR 

web page at: http://www.epa.gov/ttn/atw/rrisk/rtrpg.html. The data 
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files include detailed information for each HAP emissions release 

point for the facilities included 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 Web page, complete the following steps:

1. Within this downloaded file, enter suggested revisions to the 

data fields appropriate for that information. The data fields that 

may be revised include the following:

Data Element Definition

Control Measure Are control measures in place? 

(yes or no)

Control Measure Comment

Select control measure from list 

provided, and briefly describe 

the control measure

Delete Indicate here if the facility or 

record should be deleted

Delete Comment Describes the reason for deletion

Emissions Calculation Method 

Code For Revised Emissions

Code description of the method 

used to derive emissions. For 

example, CEM, material balance, 

stack test, etc.

Emissions Process Group

Enter the general type of 

emissions process associated with 

the specified emissions point

Fugitive Angle

Enter release angle (clockwise 

from true North); orientation of 

the y-dimension relative to true 

North, measured positive for 

clockwise starting at 0 degrees 

(maximum 89 degrees)

Fugitive Length

Enter dimension of the source in 

the east-west (x-) direction, 

commonly referred to as length 

(ft)
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Data Element Definition

Fugitive Width

Enter dimension of the source in 

the north-south (y-) direction, 

commonly referred to as width 

(ft)

Malfunction Emissions Enter total annual emissions due 

to malfunctions (tpy)

Malfunction Emissions Max 

Hourly

Enter maximum hourly malfunction 

emissions here (lb/hr)

North American Datum

Enter datum for 

latitude/longitude coordinates 

(NAD27 or NAD83); if left blank, 

NAD83 is assumed

Process Comment Enter general comments about 

process sources of emissions

REVISED Address Enter revised physical street 

address for MACT facility here

REVISED City Enter revised city name here

REVISED County Name Enter revised county name here

REVISED Emissions Release 

Point Type

Enter revised Emissions Release 

Point Type here

REVISED End Date Enter revised End Date here

REVISED Exit Gas Flow Rate Enter revised Exit Gas Flowrate 

here (ft3/sec)

REVISED Exit Gas Temperature Enter revised Exit Gas 

Temperature here (F)

REVISED Exit Gas Velocity Enter revised Exit Gas Velocity 

here (ft/sec)

REVISED Facility Category 

Code

Enter revised Facility Category 

Code here, which indicates 

whether facility is a major or 

area source

REVISED Facility Name Enter revised Facility Name here

REVISED Facility Registry 

Identifier

Enter revised Facility Registry 

Identifier here, which is an ID 

assigned by the EPA Facility 

Registry System

REVISED HAP Emissions 

Performance Level Code

Enter revised HAP Emissions 

Performance Level here

REVISED Latitude Enter revised Latitude here 

(decimal degrees)

REVISED Longitude Enter revised Longitude here 

(decimal degrees)

REVISED MACT Code Enter revised MACT Code here

REVISED Pollutant Code Enter revised Pollutant Code here

REVISED Routine Emissions Enter revised routine emissions 

value here (tpy)

REVISED SCC Code Enter revised SCC Code here

REVISED Stack Diameter Enter revised Stack Diameter here 

(ft)
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Data Element Definition

REVISED Stack Height Enter revised Stack Height here 

(ft)

REVISED Start Date Enter revised Start Date here

REVISED State Enter revised State here

REVISED Tribal Code Enter revised Tribal Code here

REVISED Zip Code Enter revised Zip Code here

Shutdown Emissions Enter total annual emissions due 

to shutdown events (tpy)

Shutdown Emissions Max 

Hourly

Enter maximum hourly shutdown 

emissions here (lb/hr)

Stack Comment Enter general comments about 

emissions release points

Startup Emissions Enter total annual emissions due 

to startup events (tpy)

Startup Emissions Max Hourly Enter maximum hourly startup 

emissions here (lb/hr)

Year Closed Enter date facility stopped 

operations

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).

4. Send the entire downloaded file with suggested revisions in 

Microsoft® Access format and all accompanying documentation to Docket 

ID Number EPA-HQ-OAR-2010-0895 (through one of the methods described 

in the ADDRESSES section of this preamble). To expedite review of the 

revisions, it would also be helpful if you submitted a copy of your 

revisions to the EPA directly at RTR@epa.gov in addition to 

submitting them to the docket.

5. If you are providing comments on a facility, you need only 

submit one file for that facility, which should contain all suggested 
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changes for all sources at that facility. We request that all data 

revision comments be submitted in the form of updated Microsoft® 

Access files, which 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 Section 3(f)(1) of Executive Order 12866 (58 FR 51735, 

October 4, 1993), this action is an "economically significant 

regulatory action‖ because it is likely to have an annual effect on 

the economy of $100 million or more. Accordingly, the EPA submitted 

this action to 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.

In addition, the EPA prepared an analysis of the potential costs 

and benefits associated with this action. This analysis is contained 

in the RIA for this proposed rule. A copy of the analysis is 

available in the docket for this action, and the analysis is briefly 

summarized abovehere.

The proposed rule will reduce emissions of directly emitted PM 

and estimates of the PM2.5 benefits of these air quality improvements 

may be found in Table 2 of this preamble. When characterizing 

uncertainty in the PM-mortality relationship, the EPA has 
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historically presented a sensitivity analysis applying alternate 

assumed thresholds in the PM concentration-response relationship. In 

its synthesis of the current state of the PM science, the EPA‘s 2009 

Integrated Science Assessment for Particulate Matter concluded that a 

no-threshold log-linear model most adequately portrays the PMmortality concentration-response relationship. In the RIA 

accompanying this rulemaking, rather than segmenting out impacts 

predicted to be associated with levels above and below a ―bright 

line‖ threshold, the EPA includes a LML analysis that illustrates the 

increasing uncertainty that characterizes exposure attributed to 

levels of PM2.5 below the LML of each epidemiological study used to 

estimate PM2.5-related premature death. 

Figures provided in the RIA show the distribution of baseline 

exposure to PM2.5, as well as the lowest air quality levels measured in 

each of the epidemiology cohort studies. This information provides a 

context for considering the likely portion of PM-related mortality 

benefits occurring above or below the LML of each study; in general, 

our confidence in the size of the estimated reduction PM2.5-related 

premature mortality diminishes as baseline concentrations of PM2.5 are 

lowered. Using the Pope, et al. (2002) study, 86 percent of the 

population is exposed at or above the LML of 7.5 μg/m3. Using the 

Laden, et al. (2006) study, 30 percent of the population is exposed 

at or above the LML of 10 μg/m3. Although the LML analysis provides 

some insight into the level of uncertainty in the estimated PM 
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mortality benefits, the EPA does not view the LML as a threshold and 

continues to quantify PM-related mortality impacts using a full range 

of modeled air quality concentrations. It is important to note that 

the monetized benefits include many but not all health effects 

associated with PM2.5 exposure. Benefits are shown as a range from 

those highlighted in Pope, et al. (2002), to those highlighted in 

Laden, et al. (2006). These models assume that all fine particles, 

regardless of their chemical composition, are equally potent in 

causing premature mortality because there is no clear scientific 

evidence that would support the development of differential effects 

estimates by particle type.

The cost and benefit analyseis areis also subject to 

uncertainties. More information on these cost uncertainties can be 

found in the RIA and in the cost memo for the proposal.

A summary of the monetized benefits and net benefits for the 

proposed rule at discount rates of 3 percent and 7 percent is in 

Table 2 of this preamble and a more detailed discussion of the 

benefits is found in section V.E of this preamble.

For more information on the benefits analysis, please refer to 

the RIA for this rulemaking, which is available in the docket.

B. Paperwork Reduction Act

The information collection requirements in this 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 
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Information Collection Request (ICR) document prepared by the EPA has 

been assigned EPA ICR number 2448.01. The information collection 

requirements are not enforceable until OMB approves them. The 

information requirements are based on notification, recordkeeping, 

and reporting requirements in the NESHAP General Provisions (40 CFR 

part 63, subpart A), which are mandatory for all operators subject to 

national emissions standards. These recordkeeping and reporting 

requirements are specifically authorized by CAA section 114 (42 

U.S.C. 7414). All information submitted to the EPA pursuant to the 

recordkeeping and reporting requirements for which a claim of 

confidentiality is made is safeguarded according to Agency policies 

set forth in 40 CFR part 2, subpart B.

We are proposing new paperwork requirements to the Ferroalloys 

Production source category in the form of increased frequency and 

number of pollutants tested for stack testing as described in 

§63.1625(c) and tighter parameter monitoring requirements to 

demonstrate continuous compliance as described in §63.1625(c)(6) and 

§63.1626. In conjunction shop building process fugitives monitoring, 

we believe that sources are currently equipped with adequate 

monitoring equipment and that the facilities will not incur a capital 

cost due to this requirement.

For this proposed rule, the EPA is adding affirmative defense to 

the estimate of burden in the ICR. To provide the public with an 

estimate of the relative magnitude of the burden associated with an 
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assertion of the affirmative defense position adopted by a source, 

the EPA has provided administrative adjustments to this ICR to show 

what the notification, recordkeeping and reporting requirements 

associated with the assertion of the affirmative defense might 

entail. The EPA‘s estimate for the required notification, reports and 

records for any individual incident, including the root cause 

analysis, totals $3,141 and is based on the time and effort required 

of a source to review relevant data, interview plant employees, and 

document the events surrounding a malfunction that has caused an 

exceedance of an emissions limit. The estimate also includes time to 

produce and retain the record and reports for submission to the EPA.

The EPA provides this illustrative estimate of this burden because 

these costs are only incurred if there has been a violation and a 

source chooses to take advantage of the affirmative defense.

Given the variety of circumstances under which malfunctions 

could occur, as well as differences among sources' operation and 

maintenance practices, we cannot reliably predict the severity and 

frequency of malfunction-related excess emissions events for a 

particular source. It is important to note that the EPA has no basis 

currently for estimating the number of malfunctions that would 

qualify for an affirmative defense. Current historical records would 

be an inappropriate basis, as source owners or operators previously 

operated their facilities in recognition that they were exempt from 

the requirement to comply with emissions standards during 
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malfunctions. Of the number of excess emissions events reported by 

source operators, only a small number would be expected to result 

from a malfunction (based on the definition above), and only a subset 

of excess emissions caused by malfunctions would result in the source 

choosing to assert the affirmative defense. Thus, we believe the 

number of instances in which source operators might be expected to 

avail themselves of the affirmative defense will be extremely small.

For this reason, we estimate no more than 1 or 2 such occurrences for 

all sources subject to subpart XXX over the 3-year period covered by 

this ICR. We expect to gather information on such events in the 

future and will revise this estimate as better information becomes 

available.

We estimate two regulated entities are currently subject to 

subpart XXX and will be subject to all proposed standards. The annual 

monitoring, reporting, and recordkeeping burden for this collection 

(averaged over the first 3 years after the effective date of the 

standards) for these amendments to subpart XXX (Ferroalloys 

Production) is estimated to be $384,000 per year. This includes 483

labor hours per year at a total labor cost of $37,000 per year, and 

total non-labor capital and operation and maintenance costs of 

$347,000 per year. This estimate includes performance tests, 

notifications, reporting, and recordkeeping associated with the new 

requirements for front-end process vents and back-end process 

operations. The total burden for the Federal government (averaged 
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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 $2,200 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. When these ICRs are approved by OMB, the Agency will publish a 

technical amendment to 40 CFR part 9 in the Federal Register to 

display the OMB control numbers for the approved information 

collection requirements contained in the final rules.

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 

EPA-HQ-OAR-2010-0895. Submit any comments related to the ICR to the 

EPA and OMB. See the 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, 

Attention: Desk Office for EPA. Because OMB is required to make a 

decision concerning the ICR between 30 and 60 days after [INSERT THE 

DATE OF PUBLICATION OF THIS PROPOSED RULE IN THE FEDERAL REGISTER], a 

comment to OMB is best assured of having its full effect if OMB 
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receives it by [INSERT THE DATE 30 DAYS AFTER THE DATE OF PUBLICATION 

IN THE FEDERAL REGISTER]. 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 proposed 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 331112 (i.e., 

Electrometallurgical ferroalloy product manufacturing), the SBA small 
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business size standard is 750 employees according to the SBA small 

business standards definitions.

After considering the economic impacts of today‘s proposed rule 

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 proposed rule 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 proposed rule 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. The 

proposed rule imposes no enforceable duties on any State, local or 

tribal governments or the private sector. Thus, this proposed rule is 

not subject to the requirements of sections 202 or 205 of the UMRA.

This proposed 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 because 

it contains no requirements that apply to such governments nor does 

it impose obligations upon them.

E. Executive Order 13132: Federalism
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This proposed rule 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 proposed rule will supersede State regulations. Thus, 

Executive Order 13132 does not apply to this proposed rule.

In the spirit of Executive Order 13132, and consistent with the 

EPA policy to promote communications between the EPA and sState and 

local governments, the EPA specifically solicits comment on this 

proposed rule from State and local officials.

F. Executive Order 13175: Consultation and Coordination with Indian 

Tribal Governments

This proposed rule 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 solicits additional comment on this 

proposed action from tribal officials.

G. Executive Order 13045: Protection of Children from Environmental 

Health Risks and Safety Risks

This proposed rule is not subject to Executive Order 13045 (62 

FR 19885, April 23, 1997) because the Agency does not believe the 
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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 this proposal, on a nationwide basis, there are 

approximately 26,000 people exposed to a cancer risk at or above one 

in one million and approximately 28,000 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 proposal is expected to significantly 

reduce the number of at-risk people due to HAP emissions from these 

sources (from between 26,000 to 28,000 people to about 1,000), 

providing significant benefit to all the demographic groups in the 

at-risk population.

This proposed rule is expected to reduce environmental impacts 

for everyone, including children. This action proposes 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. 

The public is invited to submit comments or identify peerreviewed studies and data that assess effects of early life exposure 

to manganese, lead, arsenic, nickel, or mercury.
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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, ―Actions Concerning Regulations That 

Significantly Affect Energy Supply, Distribution, or Use‖ (66 FR 

28355, May 22, 2001), because it is not likely to have significant 

adverse effect on the supply, distribution, or use of energy. This 

action will not create any new requirements and therefore no 

additional costs for sources in the energy supply, distribution, or 

use sectors.

I. National Technology Transfer and Advancement Act (NTTAA)

Section 12(d) of the National Technology Transfer and 

Advancement Act of 1995 (NTTAA), Public Law No. 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. NTTAA directs the EPA to provide Congress, 

through OMB, explanations when the agency decides not to use 

available and applicable VCS. 

This proposed rulemaking involves technical standards. The EPA 

proposes to use EPA Methods 1, 2, 3A, 3B, 4, 5, 5D, 9, 10, 26A, 30B, 

316, CARB 429, SW-846 Method 3052, SW-846 Method 7471b and EPA water 
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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 and Method 7471b.

Two VCS were identified acceptable alternatives to 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 Ambient 

Atmosphere‖ is an acceptable alternative to Method 9 under specified 

conditions. However, tThe Agency has identified 1820 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 1820 VCS and other 

information and conclusions, including the search and review results,

are in the docket for this proposed rule.

The EPA welcomes comments on this aspect of this proposed 

rulemaking and, specifically, invites the public to identify 

potentially-applicable voluntary consensus standards and to explain 

why such standards should be used in this regulation.

Under section 63.7(f) and section 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, 
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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 about 

26,000 to 28,000 people nationwide that are currently subject to 

health risks which are non-negligible (i.e., cancer risks greater 

than one in one 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 rule will reduce the number of 

people in this at-risk group from between 26,000 - 28,000 people to 

about 1,000 people. Based on this analysis, the EPA has determined 

that the proposed rule will not have disproportionately high and 

adverse human health or environmental effects on minority or low-
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income populations because it increases the level of environmental 

protection for all affected populations. 
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National Emission Standards for Hazardous Air Pollutants: 

Ferroalloys Production

List of Subjects in 40 CFR Part 63

Environmental protection, Air pollution control, Hazardous 

substances, Incorporation by reference, Reporting and recordkeeping 

requirements.

____________________________

Dated:

____________________________

Lisa P. Jackson,

Administrator.
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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]

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

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

2. Section 63.14 is amended by: to be added

a. Adding paragraph (b)(69);

b. Revising paragraph (i)(1);

c. Revising paragraph (p)(6) and adding paragraphs (p)(7) and 

(p)(8); and

d. By adding paragraphs (r)(1) and (r)(2).

§63.14 Incorporations by reference.

(b) * * *

(69) ASTM D7520-09, ―Standard Test Method for Determining the 

Opacity in a Plume in an Outdoor Ambient Atmosphere,‖ IBR approved 

for §63.1625(b)(9).

* * * * *

(i) * * *

(1) ANSI/ASME PTC 19.10–1981, ―Flue and Exhaust Gas Analyses 

[Part 10, Instruments and Apparatus],‖ IBR approved for 

§§63.309(k)(1)(iii), 63.865(b), 63.1625(b)(3)(iii), 63.3166(a)(3), 

63.3360(e)(1)(iii), 63.3545(a)(3), 63.3555(a)(3), 63.4166(a)(3), 

63.4362(a)(3), 63.4766(a)(3), 63.4965(a)(3), 63.5160(d)(1)(iii), 
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63.9307(c)(2), 63.9323(a)(3), 63.11148(e)(3)(iii), 63.11155(e)(3), 

63.11162(f)(3)(iii) and (f)(4), 63.11163(g)(1)(iii) and (g)(2), 

63.11410(j)(1)(iii), 63.11551(a)(2)(i)(C), table 5 to subpart DDDDD 

of this part, table 1 to subpart ZZZZZ of this part, and table 4 to 

subpart JJJJJJ 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 

§63.1625(b)(10), table 6 to subpart DDDDD of this part and table 5 to 

subpart JJJJJJ of this part.

* * * * *

(8) 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 

§63.1625(b)(10).

(9) 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_0
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7_10_methods_method_mercury_1631.pdf, IBR approved for 

§63.1625(b)(10).

(r) The following material is available from the California Air 

Resources Board (CARB), 1102 Q Street, Sacramento, California 95814, 

(http://www.arb.ca.gov/testmeth/vol3/M_429.pdf).

(1) Method 429, Determination of Polycyclic Aromatic Hydrocarbon 

(PAH) Emissions from Stationary Sources, Adopted September 1989, 

Amended July 1997, IBR approved for §63.1625(b)(11).

(2) [Reserved]

* * * * *

To be added

Subpart XXX—[AMENDED]

3. Section 63.1620 is added to read as follows:

§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,
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(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 [INSERT DATE OF PUBLICATION IN 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.

(f) Emission standards in this subpart apply at all times.

4. Section 63.1621 is added to read as follows:

§63.1621 What are my compliance dates?

(a) Existing affected sources must be in compliance with the 

provisions specified in §§63.1620 through 63.1630 no later than [2 

YEARS AFTER EFFECTIVE DATE OF FINAL RULE].

(b) Affected sources in existence prior to [INSERT DATE OF 

PUBLICATION OF THE PROPOSED RULE IN THE FEDERAL REGISTER] must be in 

compliance with the provisions specified in §§63.1650 through 63.1661 

by November 21, 2001 and until [2 YEARS AFTER EFFECTIVE DATE OF FINAL 

RULE]. As of [2 YEARS AFTER EFFECTIVE DATE OF FINAL RULE], the 

provisions of §§63.1650 through 63.1661 cease to apply to affected 
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sources in existence prior to [INSERT DATE OF PUBLICATION OF THE 

PROPOSED RULE IN THE FEDERAL REGISTER]. The provisions of §§63.1650 

through 63.1661 remain enforceable at a source for its activities 

prior to [2 YEARS AFTER EFFECTIVE DATE OF FINAL RULE].

(c) If you own or operate a new affected source that commences 

construction or reconstruction after [INSERT DATE OF PUBLICATION OF 

THE PROPOSED RULE IN THE FEDERAL REGISTER], you must comply with the 

requirements of this subpart by [EFFECTIVE DATE OF FINAL RULE], or 

upon startup of operations, whichever is later.

5. Section 63.1622 is added to read as follows:

§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:

Affirmative defense means, in the context of an enforcement 

proceeding, a response or defense put forward by a defendant, 

regarding which the defendant has the burden of proof, and the merits 

of which are independently and objectively evaluated in a judicial or 

administrative proceeding.

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, 
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light transmittance, or other effect to continuously monitor relative 

particulate matter loadings.

Building ventilation means a system of ventilated ducts designed 

to place the shop building under negative pressure and to capture 

process fugitive emissions from the shop building.

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, and fans.

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.
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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 fork lifts, 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.

Primary emissions means gases and emissions collected by hoods 

and ductwork located above an open furnace or under the cover of a 

semi-closed or sealed furnace.

Process fugitive emissions source means a source of hazardous 

air pollutant emissions that is associated with ferromanganese or 
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silicomanganese production, but is not the primary exhaust stream 

from an electric arc furnace, MOR or crushing and screening 

equipment, 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 or screening equipment.

Shop building means the building which houses one or more 

electric arc furnaces.

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.

6. Section 63.1623 is added to read as follows:

§63.1623 What are the emissions standards for new, reconstructed and 

existing facilities?

(a) Electric arc furnaces. You must install, operate, and 

maintain a capture system that collects the emissions from each 
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electric arc furnace (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)(6) of this section.

(1) Particulate matter emissions. 

(i) You must not discharge exhaust gases (including primary and 

tapping emissions) containing particulate matter in excess of 9.3

milligrams per dry standard cubic meter (mg/dscm), corrected to 2 

percent carbon dioxide (CO2) into the atmosphere from any new or 

reconstructed electric arc furnace. This emission limit must be met 

by any furnace vent stacks.

(ii) You must not discharge exhaust gases (including primary and 

tapping emissions) containing particulate matter in excess of 24 

mg/dscm, corrected to 2 percent carbon dioxide (CO2) into the 

atmosphere from any existing electric arc furnace. This emission 

limit must be met by any furnace vent stacks.

(2) Mercury emissions. You must not discharge exhaust gases 

(including primary and tapping emissions) containing mercury 

emissions in excess of 16 μg/dscm, corrected to 2 percent CO2 into the 

atmosphere from any new, reconstructed or existing electric arc 

furnace.

(3) Polycyclic aromatic hydrocarbon emissions. You must not 

discharge exhaust gases (including primary and tapping emissions) 
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containing polycyclic aromatic hydrocarbon emissions in excess of 89 

μg/dscm, corrected to 2 percent CO2 into the atmosphere from any new, 

reconstructed or existing electric arc furnace.

(4) Hydrochloric acid emissions. You must not discharge exhaust 

gases (including primary and tapping emissions) containing 

hydrochloric acid emissions in excess of 809 μg/dscm, corrected to 2 

percent CO2 into the atmosphere from any new, reconstructed or 

existing electric arc furnace.

(5) 

Hydrofluoric acid emissions. You must not discharge exhaust 

gases (including primary and tapping emissions) containing 

hydrofluoric acid emissions in excess of 801 μg/dscm , corrected to 2 

percent CO2 into the atmosphere from any new, reconstructed, or 

existing electric arc furnace.

(6) Formaldehyde emissions. You must not discharge exhaust gases 

(including primary and tapping emissions) containing formaldehyde 

emissions in excess of 201 μg/dscm, corrected to 2 percent CO2 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 collects all of the process fugitive emissions from the shop 

building (including tapping, casting, ladle treatment and crushing 

and screening equipment process fugitives) at a negative pressure of 
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at least 0.007 inches of water, and conveys the collected emissions 

to a control device. You must not discharge into the atmosphere 

emissions from the control device containing particulate matter in 

excess of 24 mg/dscm, corrected to 2 percent CO2.

(2) You must not cause emissions exiting from a shop building, 

to exceed 10 percent opacity for more than one 6-minute period.

(3) As an alternative to meeting the requirements specified in 

paragraph (b)(1) of this section, you can elect to demonstrate 

compliance by meeting the requirements of paragraphs (b)(3)(i) 

through (b)(3)(iii) of this section.

(i) You must install compliance monitors on or near the plant 

boundary, at locations approved by the Administrator, to demonstrate 

that the manganese concentration in air is at all times maintained 

below a 10-sample rolling average value of 0.10 μg/m3 at each monitor.

(A) Samples must be collected every 6 days. All samples are 24-

hr integrated samples.

(B) Calculate a 10-sample rolling average to demonstrate 

compliance with the action level specified in paragraph (b)(3)(i) of 

this section. Missed or invalidated samples must be made up only on 

the established site-specific 1- in 6-day schedule to include the 

required number of makeup samples to achieve a minimum of 10 valid 

samples).

(C) Collect particles in the PM10 size fraction at a set flow 

rate of 16.7 l/minute using a 47 mm Teflon filter.
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(D) Conduct the analysis using an EPA method (such as compendium 

method IO-3.5) and ensure the manganese method detection limit (MDL) 

is no greater than 0.01 μg/m3.

(E) All data, to include values below MDL, must be reported. 

Under no circumstances are data value substitutions (e.g., 1⁄2 MDL) 

acceptable.

(ii) (A) The monitoring system must include at least two ambient 

monitors and at least one of these monitors must be in a location 

that is expected to have the highest air concentrations at or near 

the facility boundary based on ambient dispersion modeling or other 

methods approved by the Administrator.

(B) You must submit a written plan describing and explaining the 

basis for the design and adequacy of the compliance monitoring 

network, the sampling, analytical and quality assurance procedures 

and the justification for any data adjustments within 45 days after 

the effective date of this subpart.

(C) The Administrator at any time may require changes in or 

expansion of, the monitoring program, including additional sampling 

and more frequent sampling, or revisions to the analytical protocols 

and network design.

(iii) Upon the first exceedance of a 10-sample rolling average, 

the source would be required within 6 months to evaluate the capture 

and control of process fugitives from the furnace building and 

implement any changes indicated to reduce process fugitives to 
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acceptable levels. Upon a next exceedance of the 10-sample rolling 

average following the 6-month implementation period, the source would 

be required to comply with the requirement to enclose the furnace 

building(s) and evacuate the emissions to a control device(s). In 

this case, the source would be required to complete the enclosure 

within 1 year from the time the next exceedance occurs.

(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 24 

mg/dscm, corrected to 2 percent CO2.

(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 3.91.5 mg/dscm, corrected

to 2 percent CO2.

(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) Emissions Averaging Option.

(1) As an alternative to meeting the emission standards 

specified in paragraphs (a)(1) through (a)(6) of this section on an 

electric arc furnace-specific basis, and if you have more than one 
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existing electric arc furnace located at one or more contiguous 

properties, which are under common control of the same person (or 

persons under common control), you may demonstrate compliance by 

emission averaging among the existing electric arc furnaces, if your 

averaged emissions for such electric arc furnaces are equal to or 

less than the applicable emission limit.

(2) As an alternative to meeting the emission standard specified 

in paragraph (b)(1) of this section on a building ventilation control 

device-specific basis, and if you have more than one existing 

building ventilation control device located at one or more contiguous 

properties, which are under common control of the same person (or 

persons under common control), you may demonstrate compliance by 

emission averaging among the existing building ventilation control 

devices, if your averaged emissions for such building ventilation 

control devices are equal to or less than the applicable emission 

limit.

(3) As an alternative to meeting the emission standard specified 

in paragraph (e) of this section on a crushing and screening 

equipment control device-specific basis, and if you have more than 

one existing crushing and screening equipment control device located 

at one or more contiguous properties, which are under common control 

of the same person (or persons under common control), you may 

demonstrate compliance by emission averaging among the existing 

crushing or screening equipment control device, if your averaged 
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emissions for such crushing or screening equipment control devices 

are equal to or less than the applicable emission limit.

(g) The averaged emissions rate from the existing equipment 

specified in paragraph (f) of this section participating in the 

emissions averaging option must be in compliance with the emission 

standards specified in paragraphs (a), (b) and (e)(1) of this section 

the compliance date specified in §63.1621. You must develop, and 

submit to the applicable regulatory authority for review and approval 

upon request, an implementation plan for emission averaging according 

to the following procedures and requirements in paragraphs (g)(1) 

through (g)(4) of this section.

(1) You must submit the implementation plan no later than 180 

days before the date that the facility intends to demonstrate 

compliance using the emission averaging option.

(2) You must include the information contained in paragraphs 

(g)(2)(i) through (g)(2)(vii) of this section in your implementation 

plan for all emission sources included in an emissions average:

(i) The identification of all existing equipment specified in 

paragraph (f) of this section in the applicable averaging group, 

including for each either the applicable HAP emission level or the 

control technology installed as of [DATE 60 DAYS AFTER EFFECTIVE DATE 

OF THE FINAL RULE] and the date on which you are requesting emission 

averaging to commence;
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(ii) A description of how you will comply with the monitoring 

procedures specified in §63.1626 for each averaging group; 

(iii) The specific control technology to be used for each piece 

of equipment specified in paragraph (f) of this section in the 

averaging group and the date of its installation or application; 

(iv) The test plan for the measurement of particulate matter, 

hydrochloric acid, hydrofluoric acid, formaldehyde and mercury 

emissions, as applicable, in accordance with the requirements in 

§63.1625 and the planned test dates to ensure that averaged units are 

tested concurrently or with minimal differences in the testing dates

testing will occur;

(v) The operating parameters to be monitored for each control 

system or device consistent with §63.1626 and a description of how 

the operating limits will be determined;

(vi) If you request to monitor an alternative operating 

parameter pursuant to §63.8, you must also include:

(A) A description of the parameter(s) to be monitored and an 

explanation of the criteria used to select the parameter(s); and

(B) A description of the methods and procedures that will be 

used to demonstrate that the parameter indicates proper operation of 

the control device; the frequency and content of monitoring, 

reporting, and recordkeeping requirements; and a demonstration, to 

the satisfaction of the applicable regulatory authority, that the 
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proposed monitoring frequency is sufficient to represent control 

device operating conditions; and

(vii) A demonstration that compliance with each of the 

applicable emission limit(s) will be achieved under representative 

operating conditions.

(3) The regulatory authority shall review and approve or 

disapprove the plan according to the following criteria:

(i) Whether the content of the plan includes all of the 

information specified in paragraph (g)(2) of this section; and

(ii) Whether the plan presents sufficient information to 

determine that compliance will be achieved and maintained.

(4) The applicable regulatory authority shall not approve an 

emission averaging implementation plan containing any of the 

following provisions:

(i) Any averaging between emissions of differing pollutants or 

between differing sources; or

(ii) The inclusion of any emission source other than an existing 

unit in the same source category.

(h) 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 
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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.

7. Section 63.1624 is added to read as follows:

§63.1624 What are the operational and work practice standards for 

new, reconstructed and existing facilities?

(a) Process fugitives sources.

(1) If you are complying with the standard specified in 

§63.1623(b)(1), you must prepare and operate according to a process 

fugitives ventilation plan for each shop building.

(2) You must prepare a process fugitives ventilation schematic 

for each shop building indicating duct size and location, enclosure 

and hood sizes and locations, control device types, size and 

locations, and exhaust locations should be developed. The process 

fugitives ventilation system schematic must be annotated with the 

location and size of each shop building air supply unit and each shop 

building exhaust fan.

(3) You must conduct a baseline survey to establish actual air 

flow and static pressure values before and after each emission 

control device and in each branch of the process ventilation system 

after each enclosure or hood. You must also determine actual air flow 

and static pressure values for each shop building air supply and 

exhaust device. You must demonstrate that air supply and exhaust are 

balanced.
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(4) You must repeat the baseline survey should at least every 5 

years or following significant ventilation system changes.

(5) The process fugitives ventilation plan must contain a 

description of each enclosure and hood with explanation demonstrating 

that adequate control of the process source is being achieved or 

actions planned to improve performance.

(6) The process fugitives ventilation plan must be adequate to 

ensure that the building is continuously maintained at a negative 

pressure of at least 0.007 inches of water.

(7) The process fugitives ventilation plan must identify 

critical maintenance actions, schedule to complete, and verification 

record of completion.

(8) You must submit a copy of the process fugitives ventilation 

plan to the designated permitting authority on or before the 

applicable compliance date for the affected source as specified in 

§63.1621. The requirement for you to operate the facility according 

to a written process fugitives ventilation 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.

(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.
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(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 

§63.1621(a). 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.

8. Section 63.1625 is added to read as follows:

§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 §63.7 of subpart A.

(2) Each performance test 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 
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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-21 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 
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pollutant sampling in order to correct pollutant concentrations for 

dilution and 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-31 of 40 CFR part 60 to determine the 

moisture content of the stack gas.

(5)(i) Method 5 of Appendix A-31 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-31 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.
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(6) Method 30B of Appendix A-81 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-81 of 40 CFR part 60 to 

determine outlet stack or inlet hydrochloric acid and hydrofluoric 

acid concentration.

(ii) Collect a minimum volume of 2 cubic meters.

(8)(i) Method 316 of Appendix A-1 of 40 CFR part 630 to 

determine outlet stack or inlet formaldehyde.

(ii) Collect a minimum volume of 1.0 cubic meter.

(9)(i)Method 10 of Appendix A-1 of 40 CFR part 60 to determine 

inlet carbon monoxide concentration.

(ii) Collect one 1-hour test run corresponding (e.g., 

overlapping in time) to each of the three formaldehyde test runs.

(910) Method 9 of Appendix A-41 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 
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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 

§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 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.

(101) Methods to determine the mercury content of manganese ore 

including a total metals digestion technique, SW-846 Method 3052, and 
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a mercury specific analysis method, SW-846 Method 7471b (Cold Vapor 

AA) or Water Method 1631E (Cold Vapor Atomic Fluorescence).

(112) 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).

(123) The owner or operator may use alternative measurement 

methods approved by the Administrator following the procedures 

described in §63.7(f) of subpart A.

(c) Compliance demonstration with the emission standards.

(1) You must conduct an initial performance test for air 

pollution control devices or vent stacks subject to §63.1623(a) 

through (e) to demonstrate compliance with the applicable emission 

standards.

(2) You must conduct performance tests every 5 years for the air 

pollution control devices and vent stacks associated with the 

electric arc furnaces and furnace building ventilation systems. The 

results of these periodic tests will be used to demonstrate 

compliance with the emission standards in §63.1623(a)(1) through 

(a)(56), (b)(1) and (b)(2), as applicable.

(3) For any air pollution control device that serves tapping 

emissions combined with non-furnace emissions, such as the MOR 

process, or equipment associated with crushing and screening, casting 
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or ladle treatment, you must conduct a performance test at least 

every 5 years. The results of these tests will be used to demonstrate 

compliance with the emission standards in §63.1623(c) through (e), as 

applicable.

(4) 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 or if 

you successfully comply with the emission averaging option specified 

in §63.1623(f).

(5) Operating Limits. You must establish parameter operating 

limits according to paragraphs (c)(5)(i) through (c)(5)(vi) 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-
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run performance test. If you use a wet acid gas scrubber and you 

conduct separate performance tests for hydrochloric acid or 

hydrofluoric 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 a dry scrubber, dry sorbent injection (DSI) system or 

activated carbon injection system, you must establish the minimum 

hourly average sorbent or activated carbon injection rate, as 

measured during the three-run performance test as your operating 

limit.

(iv) 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 §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.

(v) 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 
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Method 5 or Method 5D of Appendix A-31 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.

(v) For any furnace stack, you must establish a weighted average 

mercury concentration of the manganese ore being used in the furnace 

during the emission test. Collect a sample of all ores used in the 

furnace and prepare a weighted average based on the relative mass of 

each type of ore used in the furnace charge.

(d) Compliance demonstration with shop building opacity 

standards.

(1)(i) If you are subject to §63.1623(b)(2), you must conduct 

initial opacity observations of the shop building to demonstrate 

compliance with the applicable opacity standards according to 

§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 minimum of 60 minutes 

to include at oneleast 20 minutes of a tapping period, or at least 20 

minutes of a tapping period, whichever is less, in at least two of 

the three runs to coincide with each performance test run of the 

associated control device..
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(iii) Repeat this opacity observation at least every 5 years 

during the periodic performance tests required pursuant to paragraphs

(c)(2) of this section.

(2)(i) When demonstrating initial compliance with the shop 

building opacity standard, as required by paragraph (d)(1) of this 

section, you must simultaneously establish 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.

(ii) You may petition the Administrator to reestablish these 

parameters whenever you can demonstrate to the Administrator's 

satisfaction that the electric arc furnace operating conditions upon 

which the parameters were previously established are no longer 

applicable. The values of these parameters determined during the most 

recent demonstration of compliance must be maintained at the 

appropriate level for each applicable period.

(iii) You will demonstrate compliance by installing, operating, 

and maintaining a digital differential pressure device that shows you 

are maintaining the shop building under negative pressure to at least 

0.007 inches of water.

(3) You will demonstrate continuing compliance with the opacity 

standards by following the monitoring requirements specified in 
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§63.1626(h) and the reporting and recordkeeping requirements 

specified in §63.1629(b)(5)xx.

(e) Compliance demonstration with the operational and work 

practice standards

(1) Process fugitives 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 §60.57c(h).

9. Section 63.1626 is added to read as follows:

§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, 
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process fugitive, or outdoor fugitive dust emissions from any source 

subject to the emissions standards in §63.1623, including those used 

to control emissions from building ventilation. 

(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.
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(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 or building ventilation system, 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 (i) 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 
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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 

Qquality 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 
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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.

(vii) You must install the bag leak detection sensor downstream 

of the fabric filter.

(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 
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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.

(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 §63.16296, reduce the data to 24-hour block averages and 

maintain the 24-hour average pressure drop and liquid flow-rate at or 
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above the operating limits established during the performance test 

according to §63.1625(c)(5)(i).

(f) [Reserved]

(g) If you use a dry scrubber, DSI sorbent injection or carbon 

injection, you must collect the sorbent or carbon injection rate 

monitoring system data for the dry scrubber, DSI or ACI according to 

§63.16296, reducing the data to 24-hour block averages; and maintain 

the 24-hour average sorbent or carbon injection rate at or above the 

operating limit established during the performance test according to 

§ 63.1625(c)(5)(iii).

(h) Shop building opacity. In order to demonstrate continuous 

compliance with the opacity standards in §63.1623, you must comply 

with one of the monitoring options in paragraphs (h)(1), (h)(2), 

(h)(3) or (h)(8) of this section. The selected option must be 

consistent with that selected during the initial performance test 

described in §63.1625(d)(2). Alternatively, you may use the 

provisions of §63.8(f) to request approval to use an alternative 

monitoring method.

(1) You must check and record the control system fan motor 

amperes and capture system damper positions once per shift.

(2) You must install, calibrate, and maintain a monitoring 

device that continuously records the volumetric flow rate through 

each separately ducted hood.
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(3) You must 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.

(4) The 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.

(5) 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.

(6) Failure to maintain the appropriate capture system 

parameters (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.

(7) You must install, operate, and maintain a digital 

differential pressure monitoring system to continuously monitor each 

total enclosure as described in paragraphs (h)(7)(i) through 

(h)(7)(v) of this section.
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(i) You must install and maintain a minimum of one building 

digital differential pressure monitoring system at each of the 

following three walls in the shop building:

(A) The leeward wall.

(B) The windward wall.

(C) An exterior wall that connects the leeward and windward 

wall at a location defined by the intersection of a perpendicular 

line between a point on the connecting wall and a point on its 

furthest opposite exterior wall, and intersecting within plus or 

minus ten meters of the midpoint of a straight line between the two 

other monitors specified. The midpoint monitor must not be located on 

the same wall as either of the other two monitors.

(ii) The digital differential pressure monitoring systems must 

be certified by the manufacturer to be capable of measuring and 

displaying negative pressure in the range of 0.01 to 0.2 mm mercury 

(0.005 to 0.11 inches of water) with a minimum accuracy of plus or 

minus 0.001 mm mercury (0.0005 inches of water). 

(iii) You must equip each digital differential pressure 

monitoring system with a continuous recorder. 

(iv) You must calibrate each digital differential pressure 

monitoring system in accordance with manufacturer‘s specifications at 

least once every 12 calendar months or more frequently if recommended 

by the manufacturer.
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(v) You must equip the digital differential pressure monitoring 

system with a backup, uninterruptible power supply to ensure 

continuous operation of the monitoring system during a power outage.

(8) If you comply with the requirements specified in 

§63.1623(b)(3), you must install, operate and maintain a continuous 

monitoring system for the measurement of manganese concentrations in 

air as specified in paragraphs (h)(8)(i) through (h)(8)((v) of this 

section. 

(i) You must operate a minimum of two compliance monitors 

sufficient in location and frequency of sample collection to detect 

expected maximum concentrations of manganese in air due to emissions 

from the affected source(s) in accordance with a written plan as 

described in paragraph (h)(8)(ii) of this section and approved by the 

Administrator. The plan must include descriptions of the sampling and 

analytical methods used. At least one 24-hour sample must be 

collected from each monitor every 6 days except during periods or 

seasons exempted by the Administrator. All records pertaining to the 

implementation and results of the compliance monitoring shall be kept 

on-site for a period of no less than 5 years from the date of 

generation of the record. 

(ii) You must submit a written plan describing and explaining 

the basis for the design and adequacy of the compliance monitoring 

network, the sampling, sample handling and custody, analytical 

procedures, quality assurance procedures, recordkeeping procedures 
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and any other related procedures, and the justification for any 

seasonal, background, or other data adjustments within [45 DAYS AFTER 

EFFECTIVE DATE OF FINAL RULE].

(iii) The Administrator at any time may require changes in, or 

expansion of, the monitoring program, including additional sampling 

and, more frequent sampling, revisions to the analytical protocols 

and network design.

(iv) If all rolling 10-sample average concentrations of 

manganese in air measured by the compliance monitoring system are 

less than 50 percent of the manganese concentration limits specified 

in §63.1623(b)(3)(i) for 3 consecutive years, you may submit a 

proposed revised plan to reduce the monitoring sampling and analysis 

frequency to the Administrator for review. If approved by the 

Administrator, you may adjust your monitoring accordingly.

(v) For any subsequent period, if any rolling 10-sample average 

manganese concentration in air measured at any monitor in the 

monitoring system exceeds 50 percent of the concentration limits 

specified in §63.1623(b)(3), you must resume monitoring pursuant to 

paragraph (h)(8)(i)(A) of this section at all monitors until another 

3 consecutive years of manganese concentration measurements is 

demonstrated to be less than 50 percent of the manganese 

concentration limits specified in §63.1623(b)(3).

(i) Furnace Capture System. You must perform monthly inspections 

of the equipment that is important to the performance of the furnace 
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capture system, including capture of both primary and tapping 

emissions. This inspection must include an examination of the 

physical condition of the equipment (e.g., has hood location been 

changed or obstructed because of contact with cranes or ladles), to 

include suitable for detecting holes in ductwork or hoods, flow 

constrictions in ductwork due to dents or accumulated dust, and 

operational status of flow rate controllers (pressure sensors, 

dampers, damper switches, etc.). Any deficiencies must be recorded 

and proper maintenance and repairs performed.

(j) 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 §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 §63.8(f)(4), you may 

request approval of monitoring system quality assurance and quality 

control procedures alternative to those specified in paragraphs 
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(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 §63.8(c)(1) and (c)(3); and 

(5) Conditions that define a continuous monitoring system that 

is out of control consistent with §63.8(c)(7)(i) and for responding 

to out of control periods consistent with §63.8(c)(7)(ii) and (c)(8) 

or Appendix A to this subpart, as applicable.

(6) Ongoing recordkeeping and reporting procedures in accordance 

with provisions in §63.10(c), (e)(1) and (e)(2)(i) and Appendix A to 

this subpart, as applicable.

(k) 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 

(k)(1) through (k)(7) of this section.

(1) The continuous parameter monitoring system must complete a 

minimum of one cycle of operation for each successive 15-minute 
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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 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 
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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.

(l) For a 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. 

(m) For a CPMS for measuring liquid flow:.

(1) Use a flow sensor with a measurement sensitivity of 2 

percent of the flow rate and
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(2) Reduce swirling flow or abnormal velocity distributions due 

to upstream and downstream disturbances.

(n) For a 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).

(o) For a CPMS measuring flow of sorbent or carbon ( e.g., weigh 

belt, weigh hopper, or hopper flow measurement device),. Iinstall and 

calibrate the device in accordance with manufacturer's procedures and 

specifications.

(p) For a 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 8 hours of process operation.

(q) 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 
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matter CEMS as specified in paragraphs (qn)(1) through (qn)(43) of 

this section.

(1) You must conduct a performance evaluation of the PM CEMS 

according to the applicable requirements of §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 3 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 performance test data to the

EPA by successfully submitting the data electronically into the EPA‘s 

Central Data Exchange by using the Electronic Reporting Tool (see 

http://www.epa.gov/ttnchie1/ert/).
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(r) Ore Sampling Requirements. 

(1) Following completion of the initial compliance demonstration 

where you established a weighted average mercury concentration of the 

manganese ore being used in the furnace during the emission test, you 

must determine the weighted average mercury concentration of the 

manganese ores used in the process on a monthly basis. If you 

introduce a new type of ore, you must analyze the sample according 

the methods specified in §63.1625(b)(11) and factor the results into 

your updated weighted average mercury concentration.

(2) If the weighted average mercury concentration is more than 

10 percent higher than the weighted average operating limit, and you 

are operating an activated carbon injection system, you must reassess 

the activated carbon injection rate and revise the rate according to 

procedures established in your CMS monitoring plan.

(3) If the weighted average mercury concentration is more than 

10 percent higher than the weighted average operating limit, and you 

are not operating an activated carbon injection system, you must 

retest the control device within 30 days to demonstrate compliance 

with the mercury emission limit and establish a new weighted average 

mercury concentration and associated activated carbon injection rate.

10. Section 63.1627 is added to read as follows:

§63.1627 What is an affirmative defense for exceedence of an 

emissions limit during malfunction?
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In response to an action to enforce the standards set forth in 

paragraph § 63.1623 you may assert an affirmative defense to a claim 

for civil penalties for exceedances of such standards that are caused 

by malfunction, as defined at 40 CFR 63.2. Appropriate penalties may 

be assessed, however, if the respondent fails to meet its burden of 

proving all of the requirements in the affirmative defense. The 

affirmative defense shall not be available for claims for injunctive 

relief.

(a) Affirmative Defense. To establish the affirmative defense in 

any action to enforce such a limit, you must meet the notification 

requirements in paragraph (b) of this section, and must prove by a 

preponderance of evidence that:

(1) The excess emissions:

(i) Were caused by a sudden, infrequent, and unavoidable failure 

of air pollution control and monitoring equipment, process equipment, 

or a process to operate in a normal or usual manner; and

(ii) Could not have been prevented through careful planning, 

proper design or better operation and maintenance practices; and

(iii) Did not stem from any activity or event that could have 

been foreseen and avoided, or planned for; and

(iv) Were not part of a recurring pattern indicative of 

inadequate design, operation, or maintenance; and

(2) Repairs were made as expeditiously as possible when the 

applicable emission limitations were being exceeded. Off-shift and 
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overtime labor were used, to the extent practicable to make these 

repairs; and

(3) The frequency, amount and duration of the excess emissions 

(including any bypass) were minimized to the maximum extent 

practicable during periods of such emissions; and

(4) If the excess emissions resulted from a bypass of control 

equipment or a process, then the bypass was unavoidable to prevent 

loss of life, personal injury, or severe property damage; and

(5) All possible steps were taken to minimize the impact of the 

excess emissions on ambient air quality, the environment and human 

health; and

(6) All emissions monitoring and control systems were kept in 

operation if at all possible, consistent with safety and good air 

pollution control practices; and

(7) All of the actions in response to the excess emissions were 

documented by properly signed, contemporaneous operating logs; and

(8) At all times, the facility was operated in a manner 

consistent with good practices for minimizing emissions; and

(9) A written root cause analysis has been prepared, the purpose 

of which is to determine, correct, and eliminate the primary causes 

of the malfunction and the excess emissions resulting from the 

malfunction event at issue. The analysis shall also specify, using 

best monitoring methods and engineering judgment, the amount of 

excess emissions that were the result of the malfunction.
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(b) Notification. 

(1) If you experience an exceedence of the facilities‘ emission 

limit(s) during a malfunction, you must notify the EPA Administrator 

by telephone or facsimile (FAX) transmission as soon as possible, but 

no later than two (2) business days after the initial occurrence of 

the malfunction, if you wish to avail yourself of an affirmative 

defense to civil penalties for that malfunction. 

(2) You must also submit a written report to the EPA 

Administrator, within 45 days of the initial occurrence of the 

exceedence of the standard in § 63.1623, to demonstrate, with all 

necessary supporting documentation, that you have met the 

requirements set forth in paragraph (a) of this section. 

(3) You may seek an extension of this deadline for up to 30 

additional days by submitting a written request to the Administrator 

before the expiration of the 45-day period. Until a request for an 

extension has been approved by the Administrator, you are subject to 

the requirement to submit such report within 45 days of the initial 

occurrence of the exceedances.

11. Section 63.1628 is added to read as follows:

§63.1628 What notification requirements must I meet?

(a) You must comply with all of the notification requirements of 

§63.9 of subpart A, General Provisions. Electronic notifications are 

encouraged when possible. 
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(b)(1) You must submit the process fugitives ventilation plan 

required under §63.1624(a), the outdoor fugitives dust control plan 

required under §63.1624(b), the site-specific monitoring plan for CMS 

required under §63.1626(j), the standard operating procedures manual 

for baghouses required under §63.1626(a) and the manganese monitoring 

alternative plan required under §63.1626(h)(8) 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 [1 YEAR AFTER EFFECTIVE DATE OF FINAL 

RULE]. For sources that commenced construction or reconstruction 

after [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 

[EFFECTIVE DATE OF FINAL RULE], you must submit this notification no 

later than [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.

12. Section 63.1629 is added to read as follows:

§63.1629 What recordkeeping and reporting requirements must I meet?
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(a) You must comply with all of the recordkeeping and reporting 

requirements specified in §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 §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 2 years after the 

date of occurrence, measurement, maintenance, corrective action, 

report, or record, according to §63.10(b)(1). 

(b) You must maintain, for a period of 5 years, records of the 

information listed in paragraphs (b)(1) through (b)(132) 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 §63.1626(a) as part of the practices described in the 

standard operating procedures manual for baghouses required under 

§63.1626(c).
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(4) Electronic records of the pressure drop and water flow rate 

values for wet scrubbers used to control particulate matter emissions 

as required in §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 §63.1626(h)(1) through (h)(3), (h)(7) and 

(h)(8) , as applicable, identification of periods when the capture 

system parameters were not maintained or the manganese concentration 

exceeded the rolling 10-sample concentration level as required under 

§63.1623(b)(3) and an explanation of the corrective actions taken.

(6) Records of the results of monthly inspections of the furnace 

capture system required under §63.1626(i).

(7) Electronic records of the continuous flow monitors or 

pressure monitors required under §63.1626(j) and (k) and an 

identification of periods when the flow rate or pressure was not 

maintained as required in §63.1626(e).

(8) Electronic records of the output of any CEMS installed to 

monitor particulate matter emissions meeting the requirements of 

§63.1626(j)

(9) Records of the total sorbent injection rate required under 

§63.1626(k).
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(10) Records of the occurrence and duration of each startup 

and/or shutdown.

(110) Records of the occurrence and duration of each malfunction 

of operation (i.e., process equipment) or the air pollution control 

equipment and monitoring equipment. 

(121) Records of actions taken during periods of malfunction to 

minimize emissions in accordance with §63.1623(g), including 

corrective actions to restore malfunctioning process and air 

pollution control and monitoring equipment to its normal or usual 

manner of operation.

(132) Records that explain the periods when the procedures 

outlined in the process fugitives ventilation plan required under 

§63.1624(a), the fugitives dust control plan required under 

§63.1624(b), the site-specific monitoring plan for CMS required under 

§63.1626(j), the standard operating procedures manual for baghouses 

required under §63.1626(a) and the manganese monitoring alternative 

plan required under §63.1626(h)(8) were not followed and the 

corrective actions taken.

(c) You must comply with all of the reporting requirements 

specified in §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 §63.10(e)(3) of the General Provisions. 
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(2) Once a source reports a violation of the standard or excess 

emissions, you must follow the reporting format required under 

§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 §63.10, you must include in the reports required under 

paragraph (c) of this section the information specified in paragraphs 

(d)(1) through (d)(8) of this section.

(1) Reports that explain the periods when the procedures 

outlined in the process fugitives ventilation plan required under 

§63.1624(a), the fugitives dust control plan required under 

§63.1624(b), the site-specific monitoring plan for CMS required under 

§63.1626(j), the standard operating procedures manual for baghouses 

required under §63.1626(a) and the manganese monitoring alternative 

plan required under §63.1626(h)(8) were not followed and the 

corrective actions taken.

(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 

§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.
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(ii) Description of the actions taken following each bag leak 

detection system alarm.

(4) Reports of the shop building capture system monitoring 

required under §63.1626(h)(1) through (h)(3), (h)(7) and (h)(8) , as 

applicable, identification of periods when the capture system 

parameters were not maintained or the manganese concentration 

exceeded the rolling 10-sample concentration level as required under 

§63.1623(b)(3) and an explanation of the corrective actions taken.

(5) Reports of the results of monthly inspections of the furnace 

capture system required under §63.1626(g).

(6) Reports of the CPMS required under §63.1626, an 

identification of periods when the monitored parameters were not 

maintained as required in §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 §63.1623(g), 

including actions taken to correct a malfunction. 

(8) You must submit records pursuant to paragraphs (d)(8)(i) 

through (d)(8)(iii) of this section.
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(i) Within 60 days after the date of completing each performance 

test, as defined in §63.2 and as required in this subpart, you must 

submit performance test data, except opacity data, electronically to 

the EPA‘s Central Data Exchange by using the Electronic Reporting 

Tool (see http://www.epa.gov/ttnchie1/ert/ ). Only data collected 

using test methods compatible with the Electronic Reporting Tool are 

subject to this requirement to be submitted electronically into the 

EPA‘s WebFIRE database. 

(ii) Within 60 days after the date of completing each CEMS 

performance evaluation test, as defined in §63.2 and required by this 

subpart, you must submit the relative accuracy test audit data 

electronically into the EPA‘s Central Data Exchange by using the 

Electronic Reporting Tool as mentioned in paragraph (d)(89)(i) of 

this section. Only data collected using test methods compatible with 

the Electronic Reporting Tool are subject to this requirement to be 

submitted electronically into the EPA‘s WebFIRE database.

(iii) All reports required by this subpart not subject to the 

requirements in paragraph (d)(89)(i) and (d)(89)(ii) of this section 

must be sent to the Administrator at the appropriate address listed 

in §63.13. The Administrator or the delegated authority may request a 

report in any form suitable for the specific case (e.g., by 

electronic media such as Excel spreadsheet, on CD or hard copy). The 

Administrator retains the right to require submittal of reports 
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subject to paragraph (d)(9)(i) and (d)(9)(ii) of this section in 

paper format.

13. Section 63.1630 is added to read as follows:

§63.1630 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 §§63.1620 and 

63.1621 and 63.1623 and 63.1624.

(2) Approval of major alternatives to test methods under 

§63.7(e)(2)(ii) and (f), as defined in §63.90, and as required in 

this subpart.
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(3) Approval of major alternatives to monitoring under §63.8(f), 

as defined in §63.90, and as required in this subpart.

(4) Approval of major alternatives to recordkeeping and 

reporting under §63.10(f), as defined in §63.90, and as required in 

this subpart.

14. Section 63.1650 is amended by:

a. Revising paragraph (d);

b. Removing and reserving paragraph (e)(1); and

c. Revising paragraph (e)(2) to read as follows:

§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 [INSERT DATE OF PUBLICATION OF THE PROPOSED RULE IN 

THE FEDERAL REGISTER], must comply with the requirements of this 

subpart by May 20,1999 or upon startup of operations, whichever is 

later.

15. Section 63.1651 is amended by adding a definition for 

―Affirmative defense‖ in alphabetic order to read as follows:
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§63.1651 Definitions.

Affirmative defense means, in the context of an enforcement 

proceeding, a response or defense put forward by a defendant, 

regarding which the defendant has the burden of proof, and the merits 

of which are independently and objectively evaluated in a judicial or 

administrative proceeding.

* * * * *

16. Section 63.1652 is amended by adding paragraph (f) to read as 

follows:

§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.

17. Section 63.1656 is amended by:

a. Adding paragraph (a)(6);

b. Revising paragraph (e)(1); and

c. Removing and reserving paragraph (e)(2)(ii) to read as follows:
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§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.

* * * * * 

(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 §63.1652(f).

(2) * * *

(ii) [Reserved]

* * * * *

18. Section 63.1657 is amended by:

a. Revising paragraph (a)(6);

b. Revising paragraph (b)(3); and

c. Revising paragraph (c)(7) to read as follows:
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§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 

§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 

§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 

§63.1652(f).

19. Section 63.1659 is amended by revising paragraph (a)(4) to read 

as follows:

(a) * * *

(4) Reporting malfunctions. If a malfunction occurred during the 

reporting period, the report must include the number, duration, and a 
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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 §63.1652(f), including actions taken to correct a 

malfunction.

* * * * *

20. Section 63.1660 is amended by:

a. Revising paragraphs (a)(2)(i) and (a)(2)(ii); and 

b. Removing and reserving paragraphs (a)(2)(iv) and (a)(2)(v) to read 

as follows:

(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 §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]
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(v) [Reserved]

* * * * *

21. Section 63.1662 is added to read as follows:

§63.1662 Affirmative defense for exceedance of emission limit during 

malfunction.

In response to an action to enforce the standards set forth in 

§63.1652 through §63.1654 you may assert an affirmative defense to a 

claim for civil penalties for exceedances of such standards that are 

caused by malfunction, as defined at 40 CFR 63.2. Appropriate 

penalties may be assessed, however, if you fail to meet your burden 

of proving all of the requirements in the affirmative defense. The 

affirmative defense shall not be available for claims for injunctive 

relief.

(a) To establish the affirmative defense in any action to 

enforce such a limit, you must timely meet the notification 

requirements in paragraph (b) of this section, and must prove by a 

preponderance of evidence that:

(1) The excess emissions: 

(i) Were caused by a sudden, infrequent, and unavoidable failure 

of air pollution control and monitoring equipment, process equipment, 

or a process to operate in a normal or usual manner, and 

(ii) Could not have been prevented through careful planning, 

proper design or better operation and maintenance practices; and
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(iii) Did not stem from any activity or event that could have 

been foreseen and avoided, or planned for; and

(iv) Were not part of a recurring pattern indicative of 

inadequate design, operation, or maintenance; and

(2) Repairs were made as expeditiously as possible when the 

applicable emission limitations were being exceeded. Off-shift and 

overtime labor were used, to the extent practicable to make these 

repairs; and

(3) The frequency, amount and duration of the excess emissions 

(including any bypass) were minimized to the maximum extent 

practicable during periods of such emissions; and

(4) If the excess emissions resulted from a bypass of control 

equipment or a process, then the bypass was unavoidable to prevent 

loss of life, personal injury, or severe property damage; and

(5) All possible steps were taken to minimize the impact of the 

excess emissions on ambient air quality, the environment and human 

health; and

(6) All emissions monitoring and control systems were kept in 

operation if at all possible, consistent with safety and good air 

pollution control practices; and

(7) All of the actions in response to the excess emissions were 

documented by properly signed, contemporaneous operating logs; and

(8) At all times, the affected source was operated in a manner 

consistent with good practices for minimizing emissions; and
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(9) A written root cause analysis has been prepared, the purpose 

of which is to determine, correct, and eliminate the primary causes 

of the malfunction and the excess emissions resulting from the 

malfunction event at issue. The analysis shall also specify, using 

best monitoring methods and engineering judgment, the amount of 

excess emissions that were the result of the malfunction. 

(b) Notification. The owner or operator of the affected source 

experiencing an exceedance of its emission limit(s) during a 

malfunction shall notify the Administrator by telephone or facsimile 

(FAX) transmission as soon as possible, but no later than two 

business days after the initial occurrence of the malfunction, if it 

wishes to avail itself of an affirmative defense to civil penalties 

for that malfunction. The owner or operator seeking to assert an 

affirmative defense shall also submit a written report to the 

Administrator within 45 days of the initial occurrence of the 

exceedance of the standard in §63.1652 through §63.1654 to 

demonstrate, with all necessary supporting documentation, that it has 

met the requirements set forth in paragraph (a) of this section. The 

owner or operator may seek an extension of this deadline for up to 30 

additional days by submitting a written request to the Administrator 

before the expiration of the 45 day period. Until a request for an 

extension has been approved by the Administrator, the owner or 

operator is subject to the requirement to submit such report within 

45 days of the initial occurrence of the exceedance.
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22. 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 

Reference Applies to 

subpart 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)

63.6(g) Yes

63.6(h)(1) No

63.6(h)(2) – (h)(9) Yes .

63.6(i) Yes

63.6(j) Yes

§63.7(a)-(d) Yes

§63.7(e)(1) No See 63.1625(a)(5) and 

63.1656(a)(6)

§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 

sentence

63.8(e)-(g) Yes

63.9(a),(b),(c),(e),(g),(h)(1)thr

ough (3), (h)(5) and (6), (i) and 

(j)

Yes

63.9(f) Yes
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Reference Applies to 

subpart XXX

Comment

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 63.1629 and 

63.1660 for 

recordkeeping of 

occurrence and 

duration of 

malfunctions and 

recordkeeping of 

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 63.1629 and 

63.1630 for 

recordkeeping of 

malfunctions. 

63.10(c)(12)-(c)(14) Yes

63.10(c)(15) No

63.10(d)(1)-(4) Yes

63.10(d)(5) No See 63.1629(d)(8) and 

63.1659(a)(4) for 

reporting of 

malfunctions.

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