E.O. 12866 Review 2060-AQ42 Email thread 1 122810 .txt From: Nizich.Sharon@epamail.epa.gov Sent: Tuesday, December 28, 2010 11:10 AM To: Laney, Michael N.; Hanzel, Veronica Subject: Fw: Part of E.O. 12866 Review: EPA Staff Response to "Supplementary Information for RTR -- Primary Lead Smelting" [2060-AQ42] Attachments: DRAFT_PrimLead_RTR_Tech_Sup_Doc_12_28_10.doc; Prim Lead RTR Technology Review Memo_12_28_10.doc

Categories: Yellow Category

another email for docket.

Sharon V. Nizich Metals and Minerals Group Sector Policies and Programs Division OAQPS - US EPA RTP NC 27711 919/541-2825

----- Forwarded by Sharon Nizich/RTP/USEPA/US on 12/28/2010 11:10 AM

-----

From: Sharon Nizich/RTP/USEPA/US

To: "Higgins, Cortney" <Cortney_Higgins@omb.eop.gov>

Cc: Fred Talcott/DC/USEPA/US@EPA, Michael Stewart/RTP/USEPA/US@EPA

Date: 12/28/2010 11:10 AM

Subject: Re: Part of E.O. 12866 Review: EPA Staff Response to "Supplementary Information for RTR -- Primary Lead Smelting" [2060-AQ42]

Hello CortneyPlease find attached the required documents.

The EO 12898, (page 135), last two paragraphs will be REPLACED with the language below. Note that Fred in OP, and OGC have not reviewed yet, so this language could change.

THANKS. Page 1E.O. 12866 Review 2060-AQ42 Email thread 1 122810 .txt

(See attached file: DRAFT_PrimLead_RTR_Tech_Sup_Doc_12_28_10.doc)(See attached file: Prim Lead RTR Technology Review Memo_12_28_10.doc)

In the case of Primary Lead Processing, we focused on populations

within 50 km of the one facility in this source category with emission

sources subject to the MACT standard. More specifically, for these

populations we evaluated exposures to HAP which could result in cancer

risks of 1-in-1 million or greater, or population exposures to ambient

lead concentrations above the level of the NAAQS for lead. We compared

the percentages of particular demographic groups within the focused

populations to the total percentages of those demographic groups

nationwide. The results of this analysis are documented in section

IV.C.1 (see Table 5), as well as in a technical report located in the

docket for this rulemaking. In brief, our analyses show that although

there is the potential for adverse environmental and human health

effects from emissions of lead, there are no disparate impacts on

environmental justice populations (see section IV.C.1). Notably

however, the proposed rule would require additional control measures to

address the identified environmental and health risks and would

therefore, decrease risks to any populations exposed to these sources.

Sharon V. Nizich Metals and Minerals Group Sector Policies and Programs Division OAQPS - US EPA RTP NC 27711 919/541-2825 Page 2E.O. 12866 Review 2060-AQ42 Email thread 1 122810 .txt

From: "Higgins, Cortney" <Cortney_Higgins@omb.eop.gov>

To: Sharon Nizich/RTP/USEPA/US@EPA, Steve Fruh/RTP/USEPA/US@EPA

Cc: Ann Johnson/DC/USEPA/US@EPA

Date: 12/22/2010 03:46 PM

Subject: Supplementary Information for RTR -- Primary Lead Smelting

Hi Sharon and Steve, We’ve received the RTR Primary Lead Smelting Preamble and Reg Text. Thanks! Can you send over these documents cited in the preamble (should be 4 or 5):

- Draft Residual Risk Assessment for the Primary Lead Smelting Source Category (p 44) - Risk and Technology Review – Analysis of Socio-Economic Factors for Populations Living Near Primary Lead Smelting Operations. (p. 61) o Is this the same as the following? If not, can you send this as well?: The methodology and the results of the demographic analyses for this source category are included in the technical report available in the docket for this action. (p. 63) - Actual to Allowable Emissions Memo (p. 135) - In EO 12898 Section (EJ), discussion of 2 approaches to inhalation risk estimates that are laid out in memos (p. 135) -- we’ll need to see both

Thanks, Cortney 202.395.7856

Page 3Primary Lead Smelting NESHAP Technical Support Document



## Risk and Technology Review

National Emission Standards for Hazardous Air Pollutants (NESHAP) for the Primary Lead Smelting Source Category

Technical Support Document



# DRAFT 12/28/10

Docket No. EPA-HQ-OAR-2004-0305

January 31, 2011Primary Lead Smelting NESHAP Technical Support Document

i 

### Table of Contents

1.0 Residual Risk Analysis - Development of the Emissions Dataset for the Primary Lead Smelting Source Category ............................................................................................................... ................ 1

1.1 Emissions Data Sources .................................................................................................... .. 2

1.2 Risk Analysis Emissions Data Set ...................................................................................... 2

1.2.1 Actual Emissions ................................................................................................... 3

1.2.2 Allowable Emissions ............................................................................................. 4

2.0 Calculation of Proposed Emission Limi ts Based on Modeled Concentrations ................................ 7

3.0 Estimated Costs of Proposed Revisions to the Primary Lead Smelting NESHAP ........................ 10

3.1 Emission Control Costs for Acceptability Reductions ..................................................... 10

3.2 Emission Control Costs for Ample Margin of Safety Reductions .................................... 11

3.3 Additional Testing and Monitoring Costs ......................................................................... 13

Tables

Table 2.1 Calculations of Emission Li mits Based on Modeled Concentrations Table 2.2 Calculation of Proposed Refinery Operation Emission Limit based on Modeled Concentrations Table 3.1 Cost Effectiveness of Upgrading Baghouses to Membrane Bags for Baghouses 7, 8 and 9 Table 3.2 Cost Effectiveness of Adding A dditional Baghouses to Control Emissions for Baghouses 7, 8 and 9 Table 3.3 Cost Effectiveness of Upgrading Baghouses to Membrane Bags for Main Stack Table 3.4 Cost Effectiveness of Adding A dditional Baghouses to Control Emissions for Main Stack Table 3.5 Additional Testing and Monitoring CostsPrimary Lead Smelting NESHAP Technical Support Document

1 

### 1.0 Residual Risk Analysis ­ Development of the Emissions Dataset for

the Primary Lead Smelting Source Category

This memo describes the development of the data set used to conduct the residual risk analysis under Section 112 (f)(2) of the Clean Air Act (CAA) for the Primary Lead Smelting source
category.

Section 112 of the Clean Air Act (CAA) establishe s a two-stage regulatory process to address emissions of hazardous air pollutants (HAP) from st ationary sources. In the first stage, after EPA has identified categories of sources emitting one or more of the HAP listed in section 112(b) of the CAA, section 112(d) of the CAA ca lls for us to promulgate a National Emission Standard for Hazardous Air Pollutants (NESHAP) for those sources. These technology-based standards must reflect the maximum degree of emission reductions of HAP achievable (after considering cost, energy requirements, and non- air quality health and environmental impacts) and are commonly referred to as maximum achieva ble control technology (MACT) standards. The NESHAP for the Primary Lead Smelting sour ce category was promulgated on June 4, 1999.

The EPA is then required to review these te chnology-based standards and to revise them “as necessary (taking into account de velopments in practices, proce sses, and control technologies)” no less frequently than every 8 years, under CAA section 112(d)(6). In conducting this review, EPA is not obliged to completely recalc ulate 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 “residual” risk according to CAA section 112(f)(2) and requires EP A to determine for source categories subject to certain MACT standards, whether the emission s standards provide an ample margin of safety to protect public health. If the MACT standa rds apply to a source category emitting a HAP that is “classified as a known, proba ble, or possible human carcin ogen do not reduce lifetime excess
cancer risks to the individual mo st exposed to emissions from a source in the category or subcategory to less than one-in-one million,” 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. CAA section 112(f)(2)(A). In doing so, EPA may adopt standards equal to existing MACT standards if EPA determines that the existing standards are sufficiently protective.

In order to conduct the risk analysis of sources in the Primary Lead Smelting source category, a dataset was developed that included estimates of individual HAP emi ssions from each HAP emitting source as well as source characteristics. The dataset used includes both actual and allowable facility emissions and would be used in the emissions modeling exercise to determine
concentrations of various HAPs at the modeled receptor locations. Those concentrations would be compared to the established risk-based thre shold for each HAP to determine the potential forPrimary Lead Smelting NESHAP Technical Support Document

2 residual risk from the emissions. The methods, thresholds, and results of risk analysis and modeling are described in the “Residual Risk As sessment for the Primary Lead Smelting Source Category” memorandum included in this docket. Below is a discussion of the sources of the
actual and allowable emissions data and source ch aracteristics used in the risk analysis and modeling exercise.

1.1 Emissions Data Sources

The preliminary sources used to gather emissions and source characteristic data included the 2002 National Emissions Inventory (N EI) Final Inventory, Version 1 (made publicly available on February 26, 2006), and the 2005 National Emi ssions Inventory (NEI), version 2.0 (made publicly available in October 2008). The 2005 NEI was updated to develop the 2005 National Air Toxics Assessment (NATA) Inventory. NATA inventory updates for the primary lead smelting category included SIP da ta provided by the state of MO to EPA. These data sets
include information about sources that emit criter ia air pollutants, their precursors, and HAP.
The NEI database includes estimates of annual air pollutant emissions from point and volume sources, emission release characteristic data such as emission release he ight, temperature, and velocity, and location latitude/longitude coordina tes. We reviewed the NEI datasets, checked geographic coordinates, and made ch anges based on available information.

The sole remaining facility in this source category is the Doe Run Company in Herculaneum, Missouri. The Doe Run facility has been the su bject of many compliance and regulatory actions by the State of Missouri and by EP A Region 7 due to efforts to co mply with the lead National Ambient Air Quality Standard (NAAQS). The controls applicable to the faci lity in order to meet the NAAQS are codified in the Lead State Impl ementation Plan. In 2007 a SIP demonstration was conducted which included modeling of facility emissions to determine compliance with the
SIP. EPA also reviewed the emissions data us ed for that demonstra tion to update the risk analysis data set. Since many improvements in emissions controls have been implemented from 2001 through 2007 due to the 2001 SIP and the 2007 SIP revision, EPA determined that more recent data would be necessary to conduct an appropriate risk assessment of the current emissions impacts. EPA requested emissions a nd source control informa tion through a section 114 information collection request (ICR) in October, 2009. The February, 2010 Doe Run ICR response included copies of the emissions inve ntories that were provi ded to the Missouri Department of Natural Resources (MDNR) for the CY 2000 through 2008.

1.2 Risk Analysis Emissions Data Set

The analysis performed considers HAPs that ar e regulated by the existing MACT standard, and also considers any other HAPs that have the potential to present ri sk. The risk analysis considers both actual emissions of the facility and the em issions that would be allowable under the MACT rule. Once the analysis is complete, EPA de termines if any furthe r emission reductions arePrimary Lead Smelting NESHAP Technical Support Document

3 necessary to assure that an accep table level of risk is achieved. For the Doe Run facility, we
determined the actual and allowable emissions as described below.

1.2.1 Actual Emissions
We reviewed the NEI datasets, checked geograp hic coordinates, and made changes based on
available information. We also reviewed the emi ssions and other data to identify data anomalies
that could affect risk estimates. Since the 2008 emissions inventory is th e most recent emissions data source available, and reflects the implem entation of the numerous SIP emission reduction requirements (as evidenced by the ICR response), EPA determined that the emissions reported for the facility in the CY2008 emissions inventor y report would be the most representative of current facility operations and would also be appropriate for use in the risk analysis.

The dataset derived from the review of th e 2002 and 2005 NEI/NATA data was then updated to
include the emissions for all sources from the CY2008 emissions inventory report. Any
differences in the data between the NEI a nd the CY2008 emission inventory were noted and analyzed. If data found in the NEI was not included in the CY2008 emi ssion inventory, but was found to be pertinent, then it wa s included in the data set used for the risk analysis. Any discrepancies found between the NEI and the CY2008 emission inventory was discussed with the facility.

One specific change to the data set derived from the combination of the NEI data and the CY2008 emission inventory pertained to organic HAP em issions. The 2005 NEI file included several sources that emitted trace levels of 25 organi c HAP from natural gas and other combustion sources primarily through the main stack. The current VOC emission levels as reported in the ICR response are well below the level which can be addressed by current controls. In addition, the levels are low enough to preclude effectively modeling for risk assessment (i.e. the dispersion
from the 500 foot stack would eff ectively put any modeled emissions at zero at rece ptor sites). Therefore, the organic HAP emi ssions sources were removed from the modeling dataset and not considered during the risk analysis.

The final dataset included emissions of lead compounds and other metal HAP (i.e. antimony, arsenic, cadmium, chromium, c obalt, and nickel) which are th e HAP currently regulated under
the MACT standard.

“Lead compounds” is the primary HAP emitted from the Doe Run facility and accounts for approximately 99 percent of the total HAP emitted. Of the lead compound emissions, approximately 86 percent is emitted through stacks ( point or vertical sources) with the remainder being fugitive emissions. The point or vertic al sources include stacks that discharge from baghouses, heat stacks and roof vents. The MA CT emission limit applies to operations that discharge through 2 stacks, the main and baghous e #7 stacks which account for 15.1 of the total 17.9 TPY stack lead compound emissions. Since pr omulgation of the MACT rule, the facilityPrimary Lead Smelting NESHAP Technical Support Document

4 has captured and controlled all refining operations with two additional baghouses (baghouse #8 which vents to a stack and baghouse #9 which vents to a common stack with baghouse #7).
These emissions are included in the table below. Fugitive sources include material handling and plant yard and roadway dust. Table 1.1 summarizes the types and volumes of HAP and the types
of sources included in the dataset for the Doe Run Company facility. Total actual lead emissions including fugitive emissions are 20.7 tons per year (TPY). It should be noted that non-volatile
metal HAP other than lead ar e reported by Doe Run based on sp eciation tests c onducted for the
various sources.

Table 1.1 - Summary of Doe Run Comp any Risk Dataset Emission Sources Fugitive Stack Total

HAP Number of Sources TPY Number of Sources TPY Number of Sources TPY

Lead 115 2.8053 22* 17.9030 137 20.7083 Antimony 6 0.0028 4 0.0252 10 0.0280

Arsenic 10 0.0005 6 0.0210 4 0.0215

Cadmium 12 0.0296 7 0.0823 19 0.1118

Chromium 0 0.0000 3 0.0056 3 0.0056

Cobalt 6 0.0005 6 0.0049 12 0.0054

Nickel 8 0.0019 7 0.0154 15 0.0172 *Of the 22 stack sources, 2 are included within the MACT emission limit which account for 17.6 of the 17.9 TPY.

The actual emissions dataset for this facility repr esents the entire source category. Likewise, all HAP emission points for this sour ce are included in the risk anal ysis dataset; therefore, the facility-wide emission dataset for this source categor y is the same as the risk analysis dataset.

1.2.2 Allowable Emissions

Allowable emissions are emissions that woul d be allowed under the current NESHAP for primary lead smelters. For the Primary Lead Smelting source category and NESHAP, lead is the regulated HAP and other non-volatile metal HAP ar e regulated using lead as a surrogate. Therefore, allowable emissions would only apply for the lead compound emissions. For the Doe Run facility, allowable lead compound emissions are summarized in Table 1.2.

Under the NESHAP, an emission limit of 1.0 pound of lead per ton of lead produced (lb/ton) applies to the following nine sources:

1) Sinter machine 2) Blast furnace 3) Dross furnace 4) Dross furnace charging location 5) Blast furnace and dross furnace tapping location 6) Sinter machine charging locationPrimary Lead Smelting NESHAP Technical Support Document

5 7) Sinter machine discharge end 8) Sinter crushing and sizing equipment 9) Sinter machine area

Applying the allowable emissions rate of 1.0 lb/ton to the Do e Run’s 2008 lead production of 149,564 tons, the allowable emissions from the a bove nine sources would be 74.8 TPY. All emissions from the source’s nine emission poin ts listed above are cap tured and controlled by baghouses, which vent to the main stack or the furnace area stack. The total allowable emissions were prorated between the two stacks based on th e ratio of actual emissi ons reported for the two
stacks.

Note that refining operations are not listed above and ar e not subject to the 1.0 lb/ton limit in the original MACT. At the time the NESHAP was promulgated, refining operations were a fugitive emissions source, however, these emissions under the current facility configuration are now captured, controlled by a baghouse, and vented through two stacks. As the emissions are no longer fugitive, and the MACT emission limit does not apply to the operation, we were unable to
calculate an allowable emission le vel for refining operations.

Under the NESHAP, fugitive emissions are governed by work practices, which under §63.1544
are defined as the measures that will be “put into place to contro l fugitive dust emissions.” Thus, the actual fugitive emissions, which reflect the meas ures that have been put in place, would be equivalent to the allowable emissions. Fugitiv e emissions levels were taken from Doe Run’s 2008 Emissions Inventory that is submitted annually to the MDNR.

Table 1.2 Summary of Actual and Allowable Lead Emissions for the Doe Run Primary Lead Smelter, 2008 1

Emission Point Processes Actual Emissions

(TPY) Allowable Lead Emissions

(TPY) Main Stack (BH # 3, 5, 6) Sintering, blast furnace, dross furnace 13.31 65.8

Furnace Area (BH # 7) Smelter building 1.81 8.94 Refining (BH # 8, 9) Refining kettles and building N/A N/A Fugitives Roadways, storage piles, materials handling and transport 2.85 2.85

As shown above, we estimate that MACT-allowabl e emissions from this source category are about four times greater than th e actual emissions, based on the MA CT limit (1 lb/ton) applied to 2008 production data and compared to 2008 actual em issions. The modeling file for this risk analysis can be reviewed in the EXCEL spreadsheet

“ PrimLead_RTR_ModelingFile_102110_2008_DOE_RUN.xls ” available in the docket.Primary Lead Smelting NESHAP Technical Support Document

6 References:

1. Curran, D., Stinson Morrison Hecker, for The Doe Run Company, to Nizich, S., US EPA, Response to Section 114 Information Collection Request, February 5, 2010.Primary Lead Smelting NESHAP Technical Support Document

7 

### 2.0 Calculation of Proposed Emission Limits Based on Modeled

Concentrations

The risk analysis process included modeling of ac tual and allowable emissions to determine the anticipated concentration at individual recept or locations. For this source category, the emissions for the lead emissions sources were individually modeled fo r each receptor location and the results were compared to the Primary National Ambient Air Standard (NAAQS) for lead (0.15 μ g/m 3 ). If the modeled emissions exceeded the lead NAAQS, those locations were considered to be exposed to unacceptable risk. The results indicated multiple locations exceeded the level of the NAAQS to various degrees.

Our modeling results indicated that emissions from the main stack did not exceed NAAQS within the 50 km radius modeled. The highest concentration location wa s a point on the property boundary. Emissions contributing to this exceeda nce were found to be cumulative fugitive dust emissions from various emission points. Other em ission points that resulted in exceedance of the lead NAAQS were the furnace area stack and th e Baghouse #9 stack for the refinery building, both at various census block locations.

Each emission point (with fugitive dust emissi ons being treated as one emission point) were analyzed to determine what emission levels woul d be necessary to reduce risk to an acceptable level. EPA determined that if the emissions from each emission point were reduced below the NAAQS level based on the worst-ca se or highest location concentr ation, then all risk for that emission point at any location w ould be reduced to acceptable levels. Therefore, a roll-back calculation was conducted to determ ine what percentage reduction in concentration was required for each of the highest concentration locations. Since the relationship betw een level of emissions and modeled concentrations is linear, a percen tage reduction could be applied to the actual emissions from the CY 2008 emissions inventory for a given emission point that would reflect the same reduction in modeled concentration.

The reduction necessary to address fugitive dust emissions risk was determined to be 98 percent. The reduction necessary to address the furnace area stack emissions was determined to be 52 percent.

The refinery emissions are vented through Baghouse #8 and Baghouse #9 stacks, and ten heat stacks. For the refinery operation, only one stack (Baghouse #9) showed exceedance of the NAAQS. The emission reduction found necessary from Baghouse #9 stack is 66 percent, which was applied to the total emissions from all of the refinery operation emissions points.

Table 2.1 summarizes the calculati ons and recommended limits for the total facility including furnace area stack, fugitive dust, and the refine ry operations. Table 2.2 summarizes just the refining operation calculation, consideri ng all contributing emission points.Primary Lead Smelting NESHAP Technical Support Document8Table 2.1 - Calculations of Emission Limits Based on Modeled ConcentrationsModeled Source2008 Emissions(tpy)Highest receptorlocation Concentration Roll back %Emissions afterrollback (tpy) NotesStacks- Main 13.31 0.007 0 13.31No risk impacts within 50 km- Baghouse #7, furnace area 1.81 0.314 520.86At census block #290997006014031- Baghouse #8 - refinery kettles 2.03 0.079 0 see below Included in refinery max calculation- Baghouse #9- refinery buiding 0.45 0.352 57 see below Included in refinery max calculationTotal of BHs 7+8+9 4.29 0.745 80 15.12Refinery stacks 2.74 0.4363 660.94BHs #8, #9 and heat stacks, see refinery maxcalculationSmelter Fugitives 2.55 6.94 980.06Fume, sinter and concentrate handlingPlantwide Fugitives 0.39 1.063 86 0.06 Roadays, plant yard, resuspensionAll Fugitives 2.94 7.289 98 0.061) Emission LimitAmbient lead concentration atproperty boundary*0.15 ug/m32) Emissions CapFurance Area stack (BH#7) 0.86 TPYRefinery stacks 0.94 TPY* To address 98% reduction needed from fugitive emissions, with receptor location at property boundary.Calculations Roll back % = (Actual concentration - 0.15)/actual concentrationEmissions after rollback = 2008 emissions * (1-(rollback%/100))RECOMMENDED ACTIONSAll Modeled SourcesPrimary Lead Smelting NESHAP Technical Support Document9Table 2.2 - Calculation of Proposed Refinery Operation Emission Limit based on Modeled ConcentrationsModeled SourceModeled values at the site of max.impact for refinery stack sources(ug/m3)*50007 Baghouse #8 Stack 0.070750008 Baghouse #9 Stack 0.315050011 Refinery Kettle Heat Stack 0.001050012 Refinery Kettle Heat Stack 0.001050013 Refinery Kettle Heat Stack 0.001050014 Refinery Kettle Heat Stack 0.001050015 Refinery Kettle Heat Stack 0.001050016 Refinery Kettle Heat Stack 0.001050017 Refinery Kettle Heat Stack 0.001050018 Refinery Kettle Heat Stack 0.0011Subtotal all refinery stacks 0.4363Ratio of NAAQS to refinery max 0.34 or 0.15/.4364Percent reduction required 0.66 or 1- 0.34TPY emission cap 0.94 or (NAAQS limit * TPY refinery current)/refinery maxlb /ton on rolling avg. 90 days 0.01 or (0.94 *2000 /149,500)Refinery Maximum CalculationPrimary Lead Smelting NESHAP Technical Support Document

10 

### 3.0 Estimated Costs of Proposed Revisions to the Primary Lead Smelting NESHAP

With regard to lead emissions, we are proposing to require most of the emission sources at the facility to implement all technically feasible contro ls in order to ensure that the ambient air meets the level of the lead NAAQS, which is the level we have determined will ensure an acceptable level of risk. EPA has determined that lead co mpound emissions must be reduced to allow for an acceptable level of risk for fugitive dust emissi ons, emissions from the furnace area stack, and the refining operation. As a result, the facility w ill need to implement emission controls or other actions that will reduce lead emissions to an acceptable level and to meet the new emission limits/caps in this proposed rule. In addition, in order to demonstrat e compliance with these limits, additional ambient lead contin uous monitoring is being required. This section summarizes the impacts analysis conducted on all addi tional emission control options that were considered technologically feasible for achie ving all necessary reductions as well as those monitoring costs necessary to comply with proposed requirements.

We note that the same controls for the three emission points to reduce lead emissions are the same controls that would reduce risks from cad mium and all other metal HAP; therefore we are not proposing additional, or other controls for control of other metal HAP.

For fugitive dust emissions, which are controlled by work practices, no additional controls were evaluated because all reasonable pr actices are currently being impl emented. Therefore, there are no additional controls and cost impacts considered for fugitive dust emissions however, based on our proposed concentration limit, we have evaluate d the costs for ambient monitoring to meet the requirement. For the four stack emission poi nts, we considered the upgrading of existing baghouses from use of cloth bags to membrane bags and addition of an in-series baghouse emission as emission reduction options.

3.1 Emission Control Costs for Acceptability Reductions
Emissions from the main stack did not trigge r unacceptable risk levels however; emission reductions were required from the furnace ar ea (baghouse #7), refining kettles (baghouse #8), refinery building (baghouse #9) and fugitive dust to meet acceptability requirements. Although costs are not considered under se ction 112(f)(1) (acceptability) in order to meet acceptable risk, EPA has estimated the cost impacts for these em ission controls for the furnace area and refining operation stacks, and has also estimated the cost s for the proposed ambient lead monitoring.

EPA estimates that replacing existing cloth bags in all baghouses will provide an approximately 95 percent reduction in emissions from the em ission points controlled by baghouses.

Table 3.1 summarizes the costs and cost-effec tiveness upgrading existi ng baghouses from cloth bags to membrane bags. Table 3.2 summarizes the costs and cost-effec tiveness of adding inseries baghouses. The calculatio ns supporting the costs reflected in the summary are included in EXCEL spreadsheet DRAFT ImpactsEst_PrimLeadRTR_122210.xls found in the docket.Primary Lead Smelting NESHAP Technical Support Document

11 3.2 Emission Control Costs for Ample Margin of Safety Reductions
Once we ensure that the risk is acceptable, we then determine whether further reductions are appropriate to ensure an ample ma rgin of safety. We investigated available and feasible control options that could be implemente d by the facility to attain the additional emissions reductions to provide an ample margin of safety.

Because all feasible controls will need to be adopted in order to meet the risk acceptability reductions, there are no additional controls to consider for fugitive dust emissions, the furnace area stack, and the refinery stacks. For the main stack, additional controls were evaluated and considered with regard to risk reduction and cost under the ample margin of safety analysis.

For the main stack, our risk anal ysis indicates that the main stack emissions do not result in ambient lead levels exceeding the NAAQS based on either actual or allowable emission levels. However, we determined that it is technologicall y feasible to reduce emissions from the main stack to a level well below the allowable level of the MACT, since thos e levels are currently being achieved. We evaluated ad ditional controls such as membrane bags or add-on baghouses as a means for achieving those reductions and redu cing associated risk. We determined that the additional controls would not provide an apprec iable risk reduction (emission reduction) for the associated cost. However, we have determined that emissions allowable under MACT should be reduced under the section 112(d )(6) technology review as descri bed in the technology review memorandum found in this docket.

Table 3.3 summarizes the costs and cost-effec tiveness of upgrading existing baghouses from cloth bags to membrane bags. Table 3.4 summari zes the costs and cost-effectiveness of adding an in-series baghouse. The calculations suppor ting the costs reflected in the summary are included in EXCEL spreadsheet DRAFT ImpactsEst_PrimLeadRTR_122210.xls found in the docket.Primary Lead Smelting NESHAP Technical Support Document12Total CostInvestmentTotalAnnualizedCost2008 BaselinePb Emissions(tpy)Emission Reductionfrom upgrade*(tpy)CE($/ton)Furnace area, BH 7 81,548 27,5911.81 0.9529,043Refining, BH 8 102,032 17,048 0.45 0.21 81,179Refining BH 9 366,932 60,471 2.03 1.3 45,467*We estimate removal efficiency for membrane bag update to be between 50 and 70 percent.Cost of Upgrade toMembrane BagsTable 3.1 - Cost Effectiveness of Upgrading Baghouses to Membrane Bags for Baghouses 7, 8 and 9ImpactsSourcePb emissions (tpy)reported in 2008EIPb emission reductionwith additional BHassuming 50% RE (tpy)Pb emission reductionwith additional BHassuming 97% RE (tpy)Annualized cost ofadding extra BH's($/yr)Cost effectivenessassuming 50% RE($/ton)Cost effectivenessassuming97% RE($/ton)BH 7 1.81 0.9 1.8BH8 0.45 0.2 0.4BH 9 2.03 1.0 2.0Total 4.29 2.1 4.2 $849,750 $396,154 $204,2031Reflects costs for pulsejet baghouses2See DRAFT ImpactsEst_PrimLeadRTR_122210.xls for detail on cost analysis.RE = Removal efficiencyTable 3.2 - Cost Effectiveness of Adding Additional Baghouses to Control Emissions for Baghouses 7, 8 and 91,2Total CostInvestmentTotalAnnualizedCost2008 BaselinePb Emissions(tpy)Emission Reductionfrom upgrade*(tpy)CE($/ton)Main Stack 1,958,851 322,823 13.31 8.0 40,424*We estimate removal efficiency for membrane bag update to be between 50 and 70 percent.Cost of Upgrade toMembrane BagsTable 3.3 - Cost Effectiveness of Upgrading Baghouses to Membrane Bags for Main StackImpactsSourcePb emissions (tpy)reported in 2008EIPb emission reductionwith additional BHassuming 50% RE (tpy)Pb emission reductionwith additional BHassuming 97% RE (tpy)Annualized cost ofadding extra BH's($/yr)Cost effectivenessassuming 50% RE($/ton)Cost effectivenessassuming97% RE($/ton)Main Stack 13.31 6.7 12.9 $1,529,730 $229,862 $118,4851Reflects costs for pulsejet baghouses2See DRAFT ImpactsEst_PrimLeadRTR_122210.xls for detail on cost analysis.RE = Removal efficiencyTable 3.4 - Cost Effectiveness ofAdding Additional Baghouses to Control Emissions for the Main Stack1,2Primary Lead Smelting NESHAP Technical Support Document

13 3.3 Additional Testing and Monitoring Costs

Based on the elevated risk levels found for the furnace area stack and the refining operation stacks, EPA is proposing emission caps for those emission points. To demonstrate compliance with the new emission caps and the plant—wide emission limit, EPA is proposing to require quarterly stack testing. Although the method for te sting is the same as it was under the current MACT, the quarterly frequency requirement imposes additional impact with re gard to the cost of additional testing.

In addition, the risk analysis results indicate that modeled le ad concentrations exceed the NAAQS at several of the property boundary rece ptor locations. Since the impact at these locations is driven by fugitive dust emissions, EP A is proposing an ambient lead concentration limit at the property boundary. To demonstrate co mpliance with this limit, EPA is proposing to require ambient lead monitoring at four locations that would be most representative of the highest modeled emissions of lead.

The additional monitoring requirements will cause annual costs for the performance of additional testing and monitoring. Since EPA assumes that monitoring equipment will be leased and not purchased, there are no anticipated capital costs associated with th e new requirements. We have determined the cost for the additional testing and monitoring to meet these requirements as
summarized in Table 3.5 below.

Table 3.5 - Additional Testing and Monitoring Costs Type of Testing/Monitoring Notes Cost Annual Cost 1 Stack Testing Method 12 $13,000 per test $156,000 Ambient Lead Monitoring (lab analysis) Per required monitoring plan $127 per test $185,420

Ambient Monitoring Equipment A nnual Lease $2,500 per unit $10,000

1 Includes 12 additional stack tests (4 stacks x 3 more test s) and 4 ambient monitors, each tested 365 days per year

.1 December 28, 2010

MEMORANDUM

TO: Docket No.: EPA-HQ-OAR-2004-0305

FROM: Sharon Nizich, Project Lead Risk and Technology Review - National Emission Standards for Hazardous Air Pollutants (NESHAP) for Primary Lead Smelting

SUBJECT: Technology Review: Developments in Practices, Processes, and Control Technologies

The purpose of this memorandum is to present the results of an analysis to identify developments in practices, processes, and c ontrol technologies for ha zardous air pollutants (HAP) emission sources for the Primary Lead Smelti ng source category. This analysis is part of EPA’s review efforts in accordance with se ction 112(d)(6) of the Clean Air Act (CAA).

1.0 BACKGROUND

1.1 Requirements of Section 112(d)(6) of the CAA

Section 112 of the CAA requires EPA to es tablish technology-based standards for sources of HAP. These technology-based standard s are often referred to as maximum achievable control technology, or MACT, standa rds. Section 112 also contains provisions requiring EPA to revisit these standards. Specificall y, paragraph 112(d)(6 ) section states:

(6) REVIEW AND REVISION. – The Admini strator shall review, and revise as necessary (taking into acc ount developments in practi ces, processes, and control technologies), emission standards promul gated under this section no less often than every 8 years.

1.2 Description of Primary Lead Sm elting Source Category and NESHAP Requirements

The Primary Lead Smelting source category incl udes all facilities th at smelt lead-bearing ore concentrates to produce lead metal using pyrometallugical te chniques. The source category does not include secondary lead smel ters, lead remelters, or lead refi ners that are not located at a primary lead smelting facility. Lead is used to make various constructio n and consumer products such as batteries, paint, glass, piping, and filler. Lead sulfide (PbS) ore co ncentrates are the main feed material to primary lead smelters. The primary lead smelting process consists of PbS concentrate storage and handling, sintering of ore concentrates , sinter crushing and handling,2 smelting of sinter to lead metal, drossing (i.e ., removing the solid oxide deposits), refining and alloying of lead metal, and smelting of the drosses.

HAP is emitted from primary lead smelting as process emissions, process fugitive emissions, and fugitive dust emissions. Process emissions are associated with the exhaust gases from sinter machines and blast and dross furn aces. HAP expected in process emissions are metals (mostly lead, but also some arsenic, ca dmium, and other metals) and also may include organic compounds that result from incomplete combustion of coke and natural gas combustion. Process fugitive emissions occur at various poin ts during the smelting process (such as during charging and tapping of furnaces) and generally include metal HAP. Fugitive dust emissions result from the entrainment of dust due to mate rial handling, vehicle traf fic, and wind erosion from storage piles. All fugitive dust emissions contain metal HAP. The majority of these fugitive emissions are related to concentrate handli ng, sinter transfer, and si ntering operations.

The NESHAP for Primary Lead Smelting were promulgated on June 4, 1999 (64 FR 30194) and codified at 40 CFR part 63, subpa rt TTT. The Primary Lead Smelting MACT standard applies to affected sources of HAP at pr imary lead smelters. Primary lead smelters are defined as “...any facility engaged in the pr oduction of lead metal from lead sulfide ore concentrates through the use of pyrometallurgical techniques.” At the time of promulgation of the Primary Lead Smelting MACT rule, there were three operating lead sme lters. Today there is one operating facility, The Doe Run Resources Corporation (Doe Run) in Herculaneum, Missouri, that is subject to the MACT standard.

The Primary Lead Smelting MACT standard applies to sinter machines, blast furnaces, dross furnaces, process fugitive sources, and fugitive dust sources. Process and process fugitive emissions of lead compounds from sinter machines, blast furnaces, and dross furnaces are limited to 500 grams (g) of lead emissions per me ga gram (Mg) of lead produced (i.e., 500 g/Mg of lead produced, or 1.0 lb/ton of lead produced). Process fugitive sources that are subject to the MACT standard are dross furnace charging, blast furnace and dross furnace tapping, and the sinter machine (charging, discharge end, crushing , and sizing). Process fugitive emissions must be captured by a hood and ventilated to a baghouse or equivalent control de vice. In addition, the sinter machine area must be enclos ed in a building that is ventilated to a ba ghouse at a rate that maintains a positive in-draft through any doorway opening. The MACT standard also requires the use of bag leak detection systems for con tinuous monitoring of baghouses. For fugitive dust sources, the MACT standard requires that the ow ner or operator prepare and operate at all times according to a standard operating procedures (SOP ) manual that describes in detail the measures used to control fugitive dust emissions from plan t roadways, material storage and handling areas, sinter machine areas, furnace areas, and refining and casting areas. The work practices outlined in the SOP manual developed for compliance with a state implementation pl an is considered to be compliant with the MACT standard with regard to fugitive emissions work practice controls.

Other metal HAP emitted from the primary lead smelting processes (arsenic, cadmium, cobalt and nickel) are covered by the MACT standard by the re gulation of lead, which is a surrogate for all other nonvolatile metal HAP. Lead is not a surrogate for mercury. However, mercury emissions are not a concern for this s ource category because the mercury content of the lead sulfide ore and other materi als that could introduce mercury into the process is below the3 detection limit. Organic HAP are emitted in very small quantities from the incomplete combustion of small amounts of coke in the bl ast furnace and natural gas combustion sources such as space heating and genera tors. Although they were consider ed in the development of the 1999 MACT rule, they were not regulated because they are emitted at a rate so low as to be infeasible to reduce. Acid gas HAP were not id entified and, therefore, we re not regulated in the original MACT rule. More recent emissions data indicate that acid gas HAP are not emitted by the lead smelting process.

2.0 DEVELOPMENTS IN PRACTICES, PROCESSES, AND CONTROL TECHNOLOGIES

For the purposes of this technology review, a “development” was considered to be any of the following:

 Add-on control technology or other e quipment that was not identified and considered during the development of the NESHAP for the source category;

 Improvement in add-on control technology or other equipment that was identified and considered during NESHAP developm ent for the source category that could result in significant additi onal HAP emissions reductions;

 Work practice or operational procedure th at was not identifie d and considered during NESHAP development for the source category; and

 Process change or pollution prevention alte rnative that could be broadly applied that was not identified and considered during the development of the NESHAP for the source category.

To identify developments in practices, pr ocesses, and control technologies, we conducted searches of EPA’s RACT/BACT/LA ER clearinghouse and the internet for information on primary lead smelting. We also reviewed the state permit, state implementation plan (SIP) and the Secti on 114 information collection request (ICR) response from the one remaining primary lead smelting facility. The search results are summarized below.

At the time of the MACT rule promulga tion, HAP emissions from the primary lead smelting source category were primarily lead but also included small amounts of arsenic, cadmium, cobalt, and nickel, and low levels of combustion related organics. Emissions data from a 2010 ICR response from the onl y remaining primary lead smelter (1) confirmed that, with the exception of the leve l of emissions, the emissions profile for the facility has not changed, with lead accounting for about 99 pe rcent of the HAP emissions. Therefore, this technology review focused on developments in prac tices, processes, and control technologies applicable to lead emission sources.

2.1 Clearinghouse and Internet Searches

RACT/BACT/LAER Clearinghouse The terms “RACT”, “BACT”, and “LAER” are acronyms for different program requirements under EPA’s New Source Revi ew (NSR) program. Under EPA’s New4 Source Review (NSR) program, if a company is planning to build a new plant or modify an existing plant such that air pollution emi ssions will increase, the company must obtain an NSR permit. The NSR permit is a construction permit which requires the company to minimize air pollution emissions by changing th e process to prevent air pollution and/or installing air pollution control equipment. RACT, or Reasonabl e Available Control Technology, is required on sour ces in areas that are not meeting national ambient air quality standards (i.e. non-attainment ar eas). BACT, or Best Available Control Technology, is required on major new or modified sources in attainment areas. LAER, or Lowest Achievable Emission Rate, is required on major new or modified sources in nonattainment areas. BACT and LAER (and sometimes RACT) are determined on a caseby-case basis, usually by State or local permitting agencies. EPA established the RACT/BACT/LAER Clearinghouse, or RBLC, to provided a central database of air pollution technology information (including pa st BACT and LAER decisions contained in NSR permits) to promote the sharing of information among permitting agencies and to aid in future case-by-case determinations. Ho wever, data in the RBLC are not limited to sources subject to RACT, BACT, and LAER requirements. Noteworthy prevention and control technology decisions and information are included even if they are not related to past RACT, BACT, or LAER decisions.

The RBLC contains over 5,000 air pollution control permit determinations that can help indentify appropriate technologies to mitigate most air pollutant emission streams. It was designed to help permit applicants and reviewers to make pollution prevention and control technology decisions fo r stationary air pollution sources, and includes data submitted by several U.S. territo ries and all 50 States on over 200 different air pollutants and 1,000 i ndustrial processes.

The RBLC was searched for facilities that conduct primary lead smelting as well as for facilities in other nonferrous ma nufacturing industries. No facilities were identified during the search and no new contro l technologies or developments in existing control technologies were id entified to further reduce em issions from primary lead smelting facilities.

Internet Search A general search of the internet was conducted for information on new processes and control technologies for primary lead smelting. The search identified one new technology: a hydrometallurgical process, which could potential ly be used in lieu of pyrometallurgical smelting to produce lead metal from lead sulfide ore. The hydrometallurgical lead processing t echnology is under development and uses electrolysis and electrowinni ng to produce lead from lead ore. This technology, however, is currently only in demonstration project status and not commercially available. Therefore, it is not a proven technology and currently cannot be considered a replacement technology for primary lead smelting operations.

2.2 State SIP and ICR5 Based on our review of The Doe Run Herculaneum Title V permit, the Missouri SIP for lead, and information provided in the Secti on 114 ICR response from The Doe Run Company, we have determined that there have been adva nces in emission contro l measures since the 1999 Primary Lead Smelting MACT standard. The fo llowing paragraphs discu ss these advances and improvements.

The 1999 MACT lead emission limit for primary lead smelting was set at 1 lb/ton. The limit is a facility-wide emission limit that applie s to the aggregation of emissions discharged from the air pollution control devices used to control emissions from the following sources:

 Sinter machine;

 Blast furnace;

 Dross furnace;

 Dross furnace charging location;

 Blast furnace and dross furnace tapping location;

 Sinter machine charging location;

 Sinter machine discharge end;

 Sinter crushing and si zing equipment; and

 Sinter machine area.

A facility-wide limit format was used b ecause it was consistent with SIPs, the commingling of exhaust gases from processes to a single stack made it impossible to set limits for individual sources, it gave the facilities more flexibility in complying with the standard, and it promoted pollution prevention by giving each fac ility the ability to meet the emission limit through any combination of source re duction and control technology options.

The 1999 MACT lead limit was set using the lead emission limits from the lead SIPs for the states in which primary lead smelting sources were operational at the time of the rulemaking. EPA took each of the three lead SIP limits, in lb/day, divided them by the corresponding lead production capacity, in tons/day, and calculated a l ead emission rate in lb/ton. The results were as follows:

ASARCO - Missouri 1.0 lb/ton ASARCO - Montana 1.0 lb/ton Doe Run - Missouri 0.84 lb/ton

The values were ranked and the median value (1.0 lb/ton) was selected as representative of the MACT floor.

Since the MACT standard was promulga ted, the industry has undergone significant changes. Two of the three facilities have s hut down. As discussed above, the only remaining primary lead smelting facility is the Doe Run sm elter at Herculaneum, Missouri. Because the Doe Run facility is located in an area desi gnated as non-attainment for the lead National Ambient Air Quality Standard (NAAQS), the facility is subject to control requirements under the Missouri SIP for lead. In an effort to meet th e lead NAAQS, Missouri revised the lead SIP as it applied to the Doe Run facil ity in 2000, 2002 and 2007, requiring numerous emissions reducing6 measures and improvements to add-on control devices, processes, and work practices. SIP requirements are also incorporated into Doe Run’s Title V permit.

The SIP requirements, implemented after the 1999 MACT standard, were considered in our technology review. The SIP requirements, summa rized below, are descri bed in detail in the 2007 revision of SIP prepared by the Missouri DNR (available at http://www.dnr.mo.gov/ENV/apcp/docs/2007revision.pdf). The SIP addresses process, process fugitives, and fugitive lead emissions and requires enhancements of existing emission control technology, adding or upgrading enclosures, pr ocess changes and limitations, and work practices.

Under the SIP, fugitive dust emissions are controlled by comprehensive work practices including road watering and auto matic sprinklers, using regenera tive sweepers to remove dust from paved surfaces to reduce emissions from tr affic, maintaining a minimum water content for ore concentrate and for baghouse dust that is loaded into railcars , and inspecting the siding that encloses buildings (followed by prompt repairs if needed).

Our review found that the practices impleme nted under the SIP to control fugitive dust emissions have resulted in reductions in these emi ssions. As a result of the SIP requirements, we find that all feasible practices and controls availa ble for control of fugitive dust emissions in this industry have already been implemented. Ther efore, EPA did not find further applicable practices or controls that should be required under the MACT to reduce fugitive emissions.

Baghouses are the most common control devi ces used to control process and process fugitive emissions of lead compounds at the He rculaneum facility with the exception of the process emissions from the sinter machine, whic h are controlled by a combination of devices in series: electrostatic precipitator, baghouse, and acid plant (for control of sulfur dioxide). The buildings that house the blast furnaces, dross furn aces, and refinery kettles are also exhausted to a baghouse. Improvements to existing emission controls required by the SIP include the installation of pleated filters to lower the air-to-cloth ratio fo r baghouses, increased ventilation and improved ventilation hoods at the blast fu rnace, and using reverse flow technology for baghouse cleaning. SIP-required measures also included the installation of enclosures for unloading ore concentrate, sinter storage, and the sides of the sinter machine (which are evacuated to a baghouse).

Process changes implemented in response to the SIP to reduce emissions include a process control system for the injection of ai r through the blast furnace tuyeres located at the bottom of the blast furnace, limitations on indi vidual process and overall plant throughputs, and limiting specific operations to only certain time s of the day when the impact on ambient air concentrations is less. Emissions from malfunc tions will be reduced by alarms that sound when the baghouse fan malfunctions, an interlock system to restrict air flow into the blast furnace when the baghouse is not operating properly, and cameras for the dr oss and refinery kettles to detect kettle failure (i.e., when a plume of smoke is detected fr om the stack, the kettle burner can be immediately shut off and the problem corrected).

Under the SIP, technological improvements have also been made to the refining operations at the Doe Run facility. Under the current MACT, refining operations are not subject7 to the lead emission limit because at the time the MACT standards were developed, emissions from refining were considered fugitive in nature . In response to the SIP requirements, the Doe Run facility has enclosed the refining and casti ng operations and now exhausts the emission from the refining kettles as well as the refining building to baghouses.

Recent stack tests show that these improvement s have resulted in emissions substantially lower than are allowed under the current MACT rule. To assess the impacts of the technological improvements, lead emissions data from 2008 were compared with emissions data from 2000. Data from 2008 was selected because it reflect s the many technological improvements that have been implemented at the facility since the MACT rule promulgation. Emissions data from earlier years would not account for all of the emission reducing changes that have been implemented at the Doe Run facility given that some of the improvements were not implemented until 2007 and 2008. In 2008, lead emissions from the smelter operations sintering, blast furnace and drossing (i.e. from the main stack) were 13.31 TPY and emissions from the baghouse controlling emissions from the blast furnace and dross plant building (i.e., baghouse 7) were 1.81 TPY for a total of approximately 15.1 TPY. At the 2008 lead production rate of 149,500 tons, the emission rate at Doe Run was about 0.2 lb/ton, an 80 per cent reduction from the current MACT limit of 1 lb/ton.

The 2008 emissions of 13.31 TPY from sinterin g, blast furnace operations, and drossing operations, represent nearly 70 percent of total faci lity-wide lead emissions and reflect the annual rate of emissions achievable as a result of the technol ogical improvements that have been made since 1999. EPA believes that the level of emi ssions in 2008 support the lowering of the MACT limit to be consistent with the demonstrated level of performance.

In order to establish an emission limit that would properly reflect the facility performance, EPA used the actual 2008 annual em issions from the sintering, blast furnace and drossing operations (i.e. 13.31 TPY) and then a ccounted for variability using the 95 percent confidence upper predictive limit (UPL). The 95 percent confid ence UPL for the lead emissions is 14.8 tons. The use of the UPL to account for va riability in emissions and the emissions data used in the calculation is di scussed in Attachment 1.

To estimate the plant wide emission limit th at EPA is proposing, the technology-based emissions level for sintering, blast furnace a nd dross furnace operations (i.e., 14.8 TPY) was added to the other risk-based emission levels established for the other emission sources at the facility. The development of the plant wide emi ssion limit is described in the preamble to the proposed rule.

3.0 CONCLUSION

This review identified several developments in practices, controls or processes that have been implemented in the primary lead smelting source category since the 1999 MACT promulgation. The primary lead smelting sour ce category currently includes one operating facility compared to three at the time the MACT rule was promulgated. The one remaining facility, The Doe Run Resources Corporation, has implemented numerous work practices to control fugitive emissions and additional enclosures and improvements to add-on controls to address process and process fugitive emissions since the 1999 MACT. Additionally, refinery8 operation emissions, which were formerly fug itive, are now captured and exhausted through a baghouse.

The improvements identified in this revi ew were all requirements imposed on the Doe Run facility through the Mi ssouri Lead SIP in order to comp ly with the lead NAAQS. As a result, current emissions data indicate an appr oximate 80 percent plant wi de reduction in lead emissions since the MACT was promulgated. A lthough these lead emission reductions are not the result of the MACT requirements, EPA belie ves that the current demonstrated emission levels represent an achievable pe rformance and that a reduction in the standard is warranted to bring the standard in line w ith actual performance.

To determine the emissions level on which the new emission limit would be based, EPA used the 2008 emissions for the facility as report ed in the Section 114 ICR response for the main stack emission (which includes the sintering, blast furnace, and drossing operations), and considered variability based on recent stack te sts. EPA calculated that the new emission limit should be based on a 14.8 tons per year cont ribution from the sintering, blast furnace,and drossing operations (i.e. the main stack). This 14.8 tons per year should be included in the calculation of the facility-wide le ad emission limit taking into c onsideration any other necessary emission reductions resulting from the residu al risk analysis bei ng conducted under Section 112(f)(2) for the source category.

4.0 REFERENCES

1. Letter from Curran, D.Y., Stinson Morrison H ecker LLP to S. Nizich, US Environmental Protection Agency, Response from The Doe Run Resources Corporation to EPA’s December 4, 2009, Section 114 Information Collection Request, February 5, 2010.9 

## ATTACHMENT 1

Variability and Upper Predic tive Limit Calculation Main Stack Lead Emissions

In assessing sources’ performance, EPA may consider variability both in identifying which performers are “best” and in assessi ng their level of perf ormance. Brick MACT , 479 F. 3d at 881-82; see also Mossville Envt’l Action Now v. EPA

, 370 F.3d 1232, 1241–42 (D.C. Cir 2004) (EPA must exercise its judgment, based on an evaluation of the relevant factors and available data, to determine the level of emissi ons control that has been achieved by the best performing sources considering these sources’ operating variability).

Variability in lead producers’ performance has a number of causes. For emissions of lead compounds that are controlled by baghouses, the va riability is chiefly due to variations in performance of the control device for which both run-to-run and test-to-test variability must be accounted. 1

In determining a plant-wide emission limit, we used annual emissions discharged from the air pollution control devices used to control lead emissions from the Doe Run primary lead smelter. For this rule, we used the 2008 emissions reported by Doe Run to the State of Missouri. Variability was added only to the main stack emissions as the emission levels for the other sources had required risk-based emission levels.

We assessed variability using a statistical fo rmula designed to estimate an emissions level that is equivalent to the source’ s performance based on future compliance tests. Specifically, the calculated limit is an upper predic tion limit (UPL) calculated with the Student’s t-test using the TINV function in Microsoft Excel®. The Student’s t-test has also been used in other EPA rulemakings (e.g., NESHAP for Portla nd Cement Manufacturing; NSPS for Hospital/Medical/Infectious Waste Incinerators ; NESHAP for Industria l, Commercial, and Institutional Boilers and Process Heaters) in accounting for variab ility. A prediction interval for a future observation is an interv al that will, with a specified degree of confidence, contain the next (or some other pre-specified) randomly se lected observation from a population. In other words, the prediction interval estimates what the upper bound of future values will be, based upon present or past samples taken. The UPL cons equently represents the value which we can expect the mean of future obser vations (3-run average for lead) to fall below within a specified level of confidence, based upon the results of an independent sample fr om the same population. In other words, if we were to randomly select a future test condition from any of these sources (i.e., average of 3 runs or 30-day average) we ca n be 95 percent confident that the reported level will fall at or below the UPL value. Use of the UPL is appropriate in this rulemaking because it sets a limit any single or future source can meet based on the source’s past performance.

1 Run-to-run variability is essentially within-test variability, and encompasses variability in individual runs comprising the compliance test, and includes uncertainties in correlation of monitoring parameters and emissions, and imprecision of stack test methods and laboratory analysis. 72 FR at 54877 (Sept. 27, 2007). Test-to-test variability results from variability in pollution device contro l efficiencies over time (depending on many factors, including for fabric filters the point in the maintenance cy cle in which a fabric filter is tested). Test-to-test variability can be termed long-term variability. 72 FR at 54878.10 This formula uses a pooled variance (in the s 2 term) that encompasses all the data-point to data-point variability. Where variability was ca lculated using the UPL statistical approach, we used the sample standard devia tion calculated from the emissions da ta distributions for lead. The standard deviation is the common measure of the dispersion of the data set around an average. We note here that the methodol ogy accounts for both short-term a nd long-term variability and encompasses run-to-run and te st-to-test variability.

We adopted a form of the UPL equation that ha s been used in more recent rulemakings. See 75 FR 54970 (September 9, 2010), 75 FR 32020 (June 4, 2010) and 75 FR 31905 (June 4, 2010). The UPL used in this pr oposed rule is calculated by:

Where:

x  ̄ = 2008 annual emissions n = the number of test runs m = the number of test runs in the compliance average

s 2 = observed variance t = student t dist ribution statistic

This calculation was performed using the following Excel functions:

95 percent UPL = 2008 annual emissions + [STDEV(Test Runs) x TINV(2 x probability, n

‐ 1 degrees
of freedom)*SQRT((1/n)+(1/m))], for a one

‐ tailed t

‐ value, probability of 0.05,
and sample size of n

Figure 1 provides the UPL calculation using the recent stack test data for the main stack at the Doe Run
Herculaneum facility. Figure 2 provides a listing of stack test results.11 Figure 1 - UPL Calculations fo r Main Stack Lead Emission

UPL Pooled Variance=

Runs 2001-2008

1 2.28

2 2.35

3 3.15

4 2.85

5 0.47

6 0.58

7 0.39

8 0.43

9 0.40

ni = number test runs = 9

Total Number of sources = 1

n =Total # test runs = 9

8

This step is for QC only:

means 1.4335

1.4335 13.31 Main Stack Pb emissions (tons/yr) ‐ 2008 EI

Mean =

Pooled Variance = 1.42101

m= number future runs = 3 Method 12 test quarterly (3 runs/test)

Term1 0.4444

Term2 0.6316

Squared root Term2 0.7947

t

‐ statistic = quantile t

‐ distribution with df degrees of freedom at .95 confidence level = 1.859548033

UPL POOLED VARIANCE = 14.78779913 Doe Run Main Stack Pb

Emissions, lb/hr

NOTE: the pvalue for the t-statistic is calculated as: 2*alpha, where 1-alpha is desired confidence, so if 99% confidence is de sired then alpha=0.01 and 2*alpha=2*(0.01) 

###   2 2

1 1

1 n

i
i s x X

n

  

 

###  1 1 1 i n N

ij i j X x

n

   

1 1

n m



2 1 1
s
n m

 
     1 1 N

i
i df n

  

 

   



df t 2 1 1
s
n m

 
     1 1 i n

i ik
k i x x
n

  

###  1 N

i
i n

 

###  N

2

, 1 1

df p Xt s

n m  
      2

, 1 1

df p Xt s

n m  
     12 Figure 2 - Doe Run Herculaneum Stack Test Da ta from Section 114 ICR Response

Source Year of Test Run # Emissions

Tests Results
for Pb (lb/hr) Production during testing (tons Pb/hr) Emissions

rate during testing (lb Pb/ton Pb produced)

Main Stack 2001 1 6.07

2 4.95

3 3.13

2002 1 20.24 8.88 2.28

2 20.87 8.88 2.35

3 27.99 8.88 3.15

2003 1 25.2 8.83 2.85

2 11.92 25.38 0.47

3 14.62 25.38 0.58

2004 1 6.85 17.50 0.39

2 7.46 17.50 0.43

3 6.99 17.50 0.40

2006 1 3.3

2 4

3 4

2008 1 10.81

2 17.49

3 19.23