MEMORANDUM

TO: Conrad Chin, U.S. Environmental Protection Agency, OAQPS

FROM: Brad Nelson, EC/R

DATE : September 19, 2011

SUBJECT: Surrogate for Metal HAP Emissions for the Ferroalloys Source Category

The purpose of this memorandum is to establish whether the emissions of particulate matter (PM) can be used as a surrogate for metallic hazardous air pollutants (HAP) emissions from electric arc furnaces (EAF) for the ferroalloys production industry

. The metallic HAP emissions from this source include: arsenic, chromium, chromium VI, lead, manganese, mercury, and nickel. Since the majority of the HAP
emissions from the EAF are particulate , establishing individual emission limits for each of the metallic
H AP species emitted from th is sources would be impractical. Measuring each individual metallic HAP would be costly and would pose unreasonable compliance and monitoring burden on the regulated community. In addition, EPA and state compliance oversight and enforcement efforts would also be unreasonably costly without concurrent benefits. Therefore , it is proposed to control metallic HAP using
limits on the flue gas concentration of PM as a metallic HAP surrogate.

1.0 Background
The ferroalloys production s ource category is currently being reviewed as part of the “risk a nd technology” (RTR) review for maximum achievable control technology (MACT standards. Under the "technology review" provision of CAA section 112, EPA is required to review MACT standards and to revise them "as necessary (taking into account developments in practices, processes and control technologies)" no less frequently than every 8 years. Under the "residual risk" provision of the CAA section 112, EPA must evaluate the MACT standards within 8 years after promulgation and promulgate standards if required to provide an ample margin of safety to protect public health or prevent an adverse environmental effect. EPA has combined the two review activities into the RTR reviews for the Ferroalloys Production source category.The ferroalloy process involves the reduction smelting of metallic ores (ferrous oxides, silicon oxides,

manganese oxides) and a carbon

- source reducing agent, usually in the form of coke, charcoal, high

- and
lo w

- volatility coal, or wood chips. These materials are fed into an electric arc furnace (EAF) a t high temperatures and the carbon source reacts with the metal oxides to form carbon monoxide ( CO ) and the ferromanganese (FeMn) or silicomanganese (SiMn) produ ct

. This process also releases PM and metallic HAP from the furnace that is either captured by the furnace hood and routed to a particulate control device or is emitted as fugitive emissions. The particulate control device (e.g., fabric filter baghouse, wet venturi scrubber) achieves both reductions in PM and metallic HAP from the exhaust stream . For the fabric filter baghouse, it was estimated that emissions of PM and non

- Hg metallic HAP are reduced by 99 percent. The venturi scrubber is estimated to a chieve reductions of 05 percent for both PM and non

- Hg metallic HAP. The two particulate control devices are estimated to reduce mercury emissions by approximately 15 percent. This is because mercury is believed to be 80 percent elemental mercury, which is not captured by the particulate control device and 20 percent mercuric chloride, which can be captured by the particulate control device.

2.0 Metallic HAP Surrogate
The current NESHAP for ferroalloys production (40 CFR Part 63, subpart XXX) uses PM as a surrogate for metallic HAP by setting a PM standard for both new and existing EAFs. The recent 

### DC Circuit
Court opinion in the National Lime II (233 F.3d 625) have revised the methodologies used to determine if criteria pollutants can be used as a surrogate for HAP. The 

### DC Circuit Court stated that EPA „„may use a surrogate to regulate hazardous pollutants if it is „reasonable‟ to do so‟‟ and laid out criteria establishing a three

- part analysis for determining whether the use of PM as a surrogate f

or non

- Hg metal HAP was reasonable. The DC Circuit Court found that PM is a reasonable surrogate for HAP if: (1) „„HAP metals are invariably present in * * * PM;‟‟ (2) „„PM control technology indiscriminately captures HAP metals along with other particulat es;‟‟ and (3) „„PM control is the only means by which facilities „achieve‟ reductions in HAP metal emissions.‟‟ 233 F.3d at 639. If these criteria are satisfied and the PM emission standards reflect what the best sources achieve

— complying with CAA section 7412(d)(3)

— „„EPA is under no obligation to achieve a particular numerical reduction in HAP metal emissions.‟‟
Based on this opinion, the EPA justifies its decision to regulate PM as "a surrogate for nonvolatile HAP metals" by noting first that PM generat ed by EAFs invariably contains HAP
metals . This was confirmed from the baghouse dust data that was collected for the Information

### Collection Request (ICR) for ferroalloys production. Based on th ese results , it can be stated that

preventing the emission of a unit of PM prevents the emission of some quantum of HAP metals. Using PM as a surrogate thus "achieves exactly the same level of HAP metal emissions limitation" as would be reached were the metals to be regulated directly. The EPA also believes that the MACT floor equipment and level of control for non

- Hg HAP metals is identical to that
for PM. In addition, the use of a surrogate eliminates the cost of performance testing to comply
with numerous standards for individual metals , and also reduces the costs of EPA and state compliance oversight and enforcement efforts



### . Therefore, it was determined that PM would be used as a surrogate for non

- Hg metallic HAP ( arsenic, chromium, chromium VI, lead, manganese, and nickel) and a separ ate standard would be proposed for mercury emissions from EAFs.