Primary Lead Processing NESHAP Technical Support Document: Final Rule

Risk and Technology Review 

National Emission Standards for Hazardous Air Pollutants (NESHAP) 

for Primary Lead Processing

Technical Support Document: Final Rule

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

November 4, 2011
Primary Lead Processing NESHAP Technical Support Document: Final Rule

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Table of Contents

1.0 Residual Risk Analysis – Revisions to the Emissions Dataset from Proposal for the 

Primary Lead Processing NESHAP.................................................................................... 1

1.1 Comparison of Emission Sources..................................................................................2

1.2 Comparison of Emissions..............................................................................................2

2.0 Calculation of Final Risk-Based Emission Limits Based on Modeled Concentrations ..... 4

3.0 Model to Monitor Comparison ........................................................................................... 7

4.0 Estimated Costs of Revisions to the Primary Lead Smelting NESHAP............................. 9

4.1 Emission Control Costs for Ample Margin of Safety and Technology Review Analyses

........................................................................................................................................9

4.2 Additional Testing and Monitoring Costs....................................................................12

Tables

Table 1 Comparison of Lead Emissions (TPY) from Proposal and 2009 Doe Run Submitted 

Modeling Data 

Table 2 Calculations of Risk-Based Emission Limits Based on Modeled Concentrations

Table 3 Remodeling for Final Rule – Model-to-Monitor Comparison

Table 4 Estimated Costs for Wet Electrostatic Precipitator Control Technology for Doe Run 

Company Primary Lead Processing Facility

Table 5 Additional Testing and Monitoring Costs
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1.0 Residual Risk Analysis – Revisions to the Emissions Dataset from Proposal for 

the Primary Lead Processing NESHAP

On February 17, 2011, the EPA proposed changes to the Primary Lead Smelting NESHAP based on the

results of a residual risk analysis conducted to fulfill Section 112 (f)(2) of the Clean Air Act (CAA). In 

order to conduct the risk analysis of sources in the Primary Lead Smelting source category, an emissions

dataset was developed that included estimates of individual hazardous air pollutants (HAP) emissions 

from each HAP emitting source as well as source characteristics. Using the emissions dataset emissions

were modeled to determine concentrations of lead and other HAP at the modeled receptor locations. 

Those concentrations were compared to established risk-based thresholds for each HAP to estimate

residual risks. The methods, thresholds, and results of risk analysis and modeling are described in the 

“Residual Risk Assessment for the Primary Lead Smelting Source Category” memorandum included in 

the docket. 

The EPA solicited comments on the emissions and other data used to conduct the residual risk 

assessment and received significant comments on the data used along with submittal of revised and/or 

corrected emissions data, source characteristic information, and meteorological data. Comments on the 

modeling methodology and parameters were also received along with additional model parameter 

information. Based on the comment response, a revised emissions dataset was developed and emissions 

were remodeled. 

As part of their comments, the Doe Run Company (Doe Run) provided a modeling file developed by 

Shell Engineering which they indicated included the appropriate emissions and source characteristic 

information for the facility. The following information was extracted from the Doe Run modeling files:

• For Point sources: Source ID, X Coord. [m], Y Coord. [m], Base elevation [m], Release height 

[m], Emission rate [g/s], gas exit temperature [K], gas velocity [m/s], inside diameter [m]

• For Volume sources; Source ID, X Coord. [m], Y Coord. [m], Base elevation [m], Release height 

[m], Emission rate [g/s], side length [m], building height [m], initial lateral dimension [m], initial 

vertical dimension [m]

• For Area sources; Source ID, X Coord. [m], Y Coord. [m], Base elevation [m], Release height 

[m], Emission rate [g/s·m2

], X side length [m], y side length [m], angle from North [deg.], initial 

vertical dimension [m].

In addition, Doe Run provided particle size ranges and distributions provided hours of operation for 

several sources which indicated the distribution of the emission rate from the source file over a 24-hour 

period.
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Because the original emissions file and modeling data did not include particle distribution data or an 

operations profile, these files were not compared to the original dataset. Below is a comparison of the 

dataset used in the proposal and the dataset used for remodeling exercise. 

1.1 Comparison of Emission Sources

We compared information on emission sources from the Doe Run submittal against the source 

information in the proposal dataset. The majority of the sources submitted by Doe Run matched those in

the proposal dataset. The following list itemizes the differences found in the datasets with regard to 

sources and level of emissions;

• Baghouse 7 (Source ID 50008) emissions were accounted for under Baghouse 9, which shares a 

common stack with Baghouse 7. Emissions were combined in the modeling performed by Doe 

Run; however, emission rate estimates for each baghouse were provided in their comments.

• For proposal, Source ID 50006 was not included in the risk assessment as the facility reported 

that it no longer existed and that those emissions were now captured and vented through a

baghouse. However, the new submission reported this source with 0.0018 tpy emissions.

• Source IDs 20004, 20004B, 20004C (fume handling) and 60004 (low alpha baghouse) were 

shown with emissions totaling 0.2125 ton year and the new submission reported zero emissions 

from these sources because they are no longer operating the low alpha baghouse and the fume 

handling is now performed in such a way that fugitive emissions are not generated at those 

locations.

• Plantwide resuspension was characterized with emissions of 0.31 tpy in the proposal dataset. 

This was reported as zero emissions in the new submittal; however, Doe Run reported individual

haul road segments with a total of 0.51 tons per year of fugitive dust emissions.

1.2 Comparison of Emissions 

We used data provided in the Doe Run submittal to develop an emissions profile for modeling. 

Specifically, we used the temporal restrictions on operations of some sources to determine operating 

hours for each source. Where a specific operating scenario was not listed, we assumed even distribution 

over 24 hours for 365 days per year. We used the emission rate provided in grams per second and 

operating hours to calculate the estimated tons per year emissions for each source. We also reviewed the

new stack height data, which showed an increase in height for the Baghouse 8 and 7/9 stacks to 150 feet 

from the 100 feet in the proposal dataset. The Doe Run submittal listed the stack height for the main 

stack as 330 feet. The proposal dataset listed the stack height for the main as 550 feet which is the actual 

stack height. However, the Doe Run submittal limited the height for the main stack consistent with 

“Good Engineering Practice” which is required when modeling for NAAQS compliance demonstration.
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The difference in total lead emissions in the modeling submitted as a part of Doe Run’s comments was

an increase of 11.27 tons per year from the proposal dataset. The stacks, which include the main stack, 

Baghouse 8, Baghouse 9 account for an additional 13.49 tons of lead per year. However, as described 

more fully below, the emission rate for the main stack included in Doe Run’s modeling was not used for 

the revised risk assessment.

Lead fugitive dust emissions decreased by a total of approximately 1.54 tons per year. This included a 

65 percent increase in emissions reported for the plantwide resuspension source in the proposal dataset

and an 81 percent decrease from the reported emissions for other fugitive dust emission sources (i.e., 

concentrate, sinter and fume handling). Table 1 below summarizes the changes in lead emissions levels 

reflected in the comparison of the proposal dataset (based on 2008 emissions) and the Doe Run 

submission (based on 2009 emissions).

Table 1 Comparison of Lead Emissions (TPY) from Proposal and 2009 Doe Run Submitted 

Modeling Data

New Submittal* Proposal Dataset**

Source ID Name

Emissions 

(tpy) Name

Emissions 

(tpy) Comment:

7000#s Haul roads 0.51 plantwide 

resuspension 0.31 increase of 65%

30001 main stack*** 68.32 main stack 13.31 increase of 410%

50008 BH 7 2.46 BH7 1.81 increase of 36%

50007 BH 8 1.17 BH 8 0.45 increase of 160%

50008 BH 9 7.96 BH 9 2.03 increase of 290% 

NA Other stacks 0.40 Other stacks 0.26 increase of 55%

NA Other fugitive 0.49 Other fugitive 2.54 decrease of 81%

Total 81.31 20.71

*Based on 2009 emissions data.

**Based on 2008 emissions data.

***The main stack emission rate (19.53 tpy) included in the new submittal was not included for reasons described below.

The final dataset included emissions of lead compounds and other metal HAP (i.e. antimony, arsenic, 

cadmium, chromium, cobalt, and nickel). 

The emissions dataset for this facility represents the entire source category. Likewise, all emission points 

located at this facility and that emit HAP are included in the risk analysis dataset; therefore, the facilitywide emission dataset is the same as the risk analysis dataset for this source category. 

The emission rate for the main stack was revised using the results of a 2009 stack test submitted by Doe 

Run rather than the rate provided in the Doe Run modeling run submittal. The lead emission rate for the 

main stack included in Doe Run’s modeling was based on an emission factor used since 2004 that was 
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not reflective of the emission rate measured during the stack test performed for their 2009 compliance 

demonstration. The emission rate of 68.32 tons per year that was modeled for the revised risk 

assessment is likely a conservative estimate of annual emissions. This emission rate does not reflect the 

fact that some downtime occurs throughout the year during which sources emitting through the main 

stack are not operating. 

The emissions and source parameters used in the residual risk modeling conducted for the final rule can 

be reviewed in the docket of this rule.

2.0 Calculation of Final Risk-Based Emission Limits Based on Modeled 

Concentrations 

The final risk analysis modeled actual lead emissions to determine lead concentration at individual 

receptor locations. For this source category, the emissions for the lead emissions sources were 

individually modeled for each receptor location and the results were compared to the Primary National 

Ambient Air Quality Standard (NAAQS) for lead (0.15 μg/m3

). If the modeled emissions exceeded the 

lead NAAQS, the risk at that location was considered to be unacceptable. The results indicated multiple 

locations exceeded the level of the NAAQS to various degrees. 

Modeling results indicated that the highest concentration location was a point on the property boundary. 

Emissions contributing to this concentration were cumulative stack emissions (Baghouse 7/9 stack and

Baghouse 8 stack were the largest contributors) and fugitive dust emissions. As in the proposal 

modeling, the emissions from the main stack did not exceed NAAQS within the 50 km radius modeled

area.

Each emission point (with roadways and all other fugitive dust emissions being treated as one emission 

point) was analyzed to determine what emission levels would be necessary to reduce risk to an 

acceptable level (i.e., such that modeled emissions met or were below the level of the NAAQS). The

EPA assumes that if the highest or worst-case concentration at a receptor location resulting from the 

emissions from each emission point were reduced to below the NAAQS level, then the risks for that 

emission point at any location would be reduced to an acceptable level. Further, the EPA assumes that a 

reduction in emissions from an emission point will result in a proportionate reduction in the modeled 

concentration at a given receptor location. Since the relationship between level of emissions and 

modeled concentrations is assumed to be linear, a percentage reduction applied to an annual emissions

rate for a given emission point would produce the same reduction in modeled concentrations. A

calculation was made for each emission point to determine what percent reduction in concentration was 

required for each of the highest concentration locations to meet the NAAQS. 

The risk assessment projected ambient lead concentrations from fugitive dust emissions to be very close 

to the NAAQS for lead at the location of maximum impact. With respect to fugitive dust emissions, only 

minimal (if any) reductions beyond those already in place are needed to ensure lead levels in the air do 
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not exceed the NAAQS. The furnace area is vented through Baghouse 7 and exhausts through a stack 

shared with Baghouse 9. The refining operations consist of the refining kettles and refining building 

which exhaust through Baghouse 8 and Baghouse 9, respectively. Our analysis indicated that the 

maximum lead concentration location for the furnace area (Baghouse 7) and refinery operations

(Baghouse 8 and 9) overlapped at the same census block. Therefore, their combined concentrations at 

that location would be the driver for the reduction from these emission points. The reduction necessary 

for the combined furnace area stack and refinery stack emissions from the emission levels provided by 

Doe Run in their comments was determined to be approximately 90 percent. 

For the combined furnace area and refining operations stacks the total emissions reported were 11.56

tons per year; the new lead emission limit for the combined furnace area and refining operations stacks 

would be 1.2 tons per year. 

Table 2 summarizes the calculations and recommended limits for the furnace area/refinery stacks.
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Table 2 - Calculations of Risk-Based Emission Limits Based on Modeled Concentrations

Modeled Source

2009 

Emissions 

Maximum 

Modeled Lead 

Concentration*

Rollback to 

Meet 

0.15μg/m3*

Estimated 

Emissions 

After Rollback

(tpy) (μg/m3) % (tpy)

Stacks 

 - Baghouse 8 & 9(refinery) 9.1 1.16 87 1.2

 - Baghouse 7 (furnace area) 2.5 0.31 52 1.2

 Combined Stacks 11.6 1.47 90 1.2

FINAL EMISSION LIMIT

 Furnace Area and Refinery Stacks 1.2 TPY

Calculations:

 Roll back % = (Actual concentration - 0.15)/actual concentration

 Emissions after rollback = 2009 emissions * (1-(rollback%/100))
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3.0 Model to Monitor Comparison

In the proposed rule the EPA compared the maximum modeled estimates of ambient air lead 

concentrations with those measured at four monitors located close to the Doe Run facility in 

Herculaneum, Missouri for calendar year 2008. More specifically, the maximum 3-month rolling 

average lead concentrations (for calendar year 2008) calculated from data reported at the Main Street, 

Circle Street, South Cross, and Church Street monitors were compared to the maximum 3-month rolling 

average lead concentrations at model receptor locations in close proximity to these monitoring sites. 

Results of this analysis were presented in the proposal preamble and indicated that with respect to the 

Main Street and Circle Street monitors, AERMOD underestimated 3-month maximum lead 

concentrations by approximately 2.8- and 4.2-fold, respectively. The EPA received comment that the 

modeled-to-monitored ratio was too high indicating that the modeled results were not reasonably in 

agreement with modeled concentrations. According to commenters, the model-to-monitor ratio should 

have been less than two in order to demonstrate that the AERMOD estimates are a reasonable 

representation of the measured 3-month maximum lead concentrations in the ambient air near this 

facility.

For the final rule, the facility emissions were remodeled based on revised and new information 

submitted through the public comment process. A model-to-monitor comparison was conducted for six 

monitor locations close to the facility for the year 2009. The resulting model-to-monitor ratio indicates 

that for any monitor analyzed, the maximum modeled concentration is within 50% of the maximum 

monitored concentration at the same location which demonstrates a reasonable agreement of the 

modeled concentrations with the monitored concentrations at the six monitor locations. Table 3 provides 

a summary of the model-to-monitor comparison for the remodeling of emissions data for the final rule.
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Table 3 Remodeling for Final Rule – Model-to-Monitor Comparison

Monitor Name Latitude Longitude

AERMOD 

Modeled Lead 

Concentration2 

(μg/m3)

Maximum 

Monitored Lead 

Concentration2 

(μg/m3)

Max Modeled/

Max Monitored

Percent 

Difference 3

City Hall/Main St. 4238290 729319 0.776 1.2 64.67% -35.33%

Sherman 4239206 729503 0.19 0.16 118.75% 18.75%

North Cross 4238151 729121 0.34 0.59 57.63% -42.37%

High School/Dunklin 4238702 729334 0.343 0.39 87.95% -12.05%

Church St. 4237753 729168 0.601 0.45 133.56% 33.56%

Ursuline1 4235800 729617 0.073 0.08 91.25% -8.75% 1

There is no 2009 data for this monitor. The value for "Max Monitored" is from 2010.

2 Maximum 3-month average

3 Negative value = model underestimation
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4.0 Estimated Costs of Revisions to the Primary Lead Smelting NESHAP

With regard to lead emissions, we are finalizing emission limits that are consistent with the results of our 

risk and technology reviews of the current NESHAP for primary lead processing. We found that no 

emission reductions were required from the main stack to achieve acceptable risk. Under our ample 

margin of safety technology review analyses, we evaluated addition controls beyond the existing level of 

control for the main stack as well as the refining and furnace area stacks to determine if a reduced 

standard was warranted in order to provide an ample margin of safety, or whether there were 

developments in practices, processes, or control technologies that warranted a reduced standard

considering cost and technical feasibility. 

Although our analysis indicated that additional controls were not warranted for the main stack to achieve 

acceptable risk, we are reducing the main stack emission limit under section 112(d)(6) to reflect 

performance achievable from technological improvements. In addition we are increasing the frequency 

of monitoring stack emission from the current annual emissions testing to quarterly testing. This section, 

therefore, also includes estimates of the impacts for the additional monitoring costs necessary to comply 

with final emission limit requirements. 

In the proposed rule for the main stack emission point, we considered and rejected the option of 

upgrading existing controls by adding in-series baghouses. During the public comment period, 

commenters suggested that the EPA evaluate wet electrostatic precipitators as polishing control devices 

in the analysis performed under section 112(d)(6) of the CAA and the ample margin of safety analysis 

performed under section 112(f) of the CAA. The EPA has determined wet electrostatic precipitators

(WESP) may be technologically feasible for achieving additional emission reductions from the main 

stack, refinery stacks, and furnace area stack, but the technology is not economically feasible in this 

case. Therefore, we are not requiring a reduced emission standard that reflects the performance of 

WESP technology for these three stacks. This section summarizes the impacts analysis that was 

conducted on adding this additional emission control option to the existing control configuration.

We note that the controls that reduce lead emissions are the same controls that would reduce emissions 

and risks from other metal HAP; therefore we are not proposing additional controls for other metal 

HAP. We further note that the analysis for the ample margin of safety determination and the technology 

review both evaluated the same technology. This technology has been determined to be cost prohibitive 

in both analyses.

4.1 Emission Control Costs for Ample Margin of Safety and Technology Review Analyses

Once we determine that risk will be reduced to a level that is acceptable, we then determine whether 

further reductions are appropriate to ensure an ample margin of safety. We investigated available control 

options that could be implemented by the facility to attain the additional emissions reductions that would

provide an ample margin of safety. 

No additional controls other than the WESP technology described in public comments were identified to 

further control emissions from the furnace area stack or the refinery stacks that are already controlled 

with baghouses using membrane bags. 
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For the main stack, our risk analysis indicates that emissions do not result in ambient lead levels 

exceeding the NAAQS based on the actual emission levels. However, we determined that it is 

technologically feasible to reduce emissions from the main stack to a level below the allowable level of 

the MACT, since those levels are currently being achieved. We evaluated additional controls beyond 

what is already achieved such as a WESP for achieving further reductions and reducing associated risk. 

The investment required to install a polishing control device after the baghouses ducted to the main 

stack would approach $100 million dollars. We determined that the additional controls would not be 

economically feasible based on the associated cost. However, we have determined that emissions 

allowable under MACT should be reduced under the section 112(d)(6) technology review as described 

in the technology review memorandum found in the docket for this action. There is no cost associated 

with the revised main stack emission standard promulgated under section 112(d)(6) as this level of 

emissions is already achieved. As with the main stack, we evaluated the cost of installing WESPs on the 

stacks for which emission standards are being promulgated under 112(f) during our ample margin of 

safety and 112(d)(6) technology review analyses. The cost of installing WESPs on Baghouses 7/9 and 

Baghouse 8 is approximately $50 million dollars. This cost is prohibitively high and makes the 

reductions based on installation of WESPs on these sources economically infeasible. Based on the 

economic infeasibility of installing additional control devices, reductions in the emission standards 

based on WESP technology were rejected under the 112(f) ample margin of safety analysis and the 

112(d)(6) technology review.

Table 4 summarizes the costs and cost-effectiveness of adding a WESP to the main stack, the Baghouse 

7 & 9 stack, and Baghouse 8 stack.
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Table 4 Estimated Costs for Wet Electrostatic Precipitator Control Technology for Doe Run Company Primary Lead 

Processing Facility

Cost Efficiency at 95% RE

Source

Volumetric Flow 

(cfm)

Total Capital 

Investment

Total Annual Costs

($US)

Emissions Reduction

(tons)

Control Efficiency 

($/ton of lead)

Main stack 1,023,723 $ 86,104,296 $ 15,355,845 65 $237,707

BH 7 & 9 * 519,614 $ 44,354,995 $ 7,794,210 9 $901,586

BH 8 76,274 $ 7,638,460 $ 1,144,110 2 $487,582

* Baghouses 7 and 9 are discharged to the same stack. Therefore, costing was based on air flow for both baghouses
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4.2 Additional Testing and Monitoring Costs

To demonstrate compliance with the new 0.97 lb/ton emission limit, EPA is requiring quarterly stack 

testing. Although the method for testing is the same as it was under the current MACT, the quarterly 

frequency requirement imposes additional impact with regard to the cost of additional testing. Quarterly 

stack testing will also be required for the baghouse 7/9 and baghouse 8 stacks.

The additional testing and monitoring requirements will result in additional cost as summarized in Table

5.

Table 5 - Additional Testing and Monitoring Costs

Type of Testing/Monitoring Notes Cost Annual Cost

Main Stack Testing1 Method 12 $13,000 per test $39,000

Baghouse 7/9 Stack Testing Method 12 $13,000 per test $52,000

Baghouse 8 Stack Testing Method 12 $13,000 per test $52,000 1 Includes 3 additional stack tests
Primary Lead Processing NESHAP Technical Support Document: Final Rule

Appendix A 

Page 1

APPENDIX A

Cost Estimates for West Electrostatic Precipitator Control Technology

For Doe Run Company Primary Lead Processing Facility

Based on

EPA Cost Manual
Primary Lead Processing NESHAP Technical Support Document: Final Rule

Appendix A 

Page 1

WESP Cost Estimates - EPA Cost Manual

DEC

volumetric flow rate A B .67B .57B 5$/CFM

Main Stack 1,023,723 cfm

WESP 

initial Cost Cost

Purchased 

equipment 

cost

Direct 

Installation 

Costs

Total Direct 

Costs

Indirect 

Installation 

Costs

TCI TAC O&M

for 95% efficiency 22.6 $/cfm $32,075,778 $32,575,778 $38,439,418 $25,754,410 $64,193,828 $21,910,468 $86,104,296 $15,355,845 $5,118,615

for 90% efficiency 18 $/cfm $25,547,080 $26,047,080 $30,735,554 $20,592,821 $51,328,375 $17,519,266 $68,847,641 $14,332,122 $5,118,615

for 85% efficiency 14.7 $/cfm $20,863,448 $21,363,448 $25,208,869 $16,889,942 $42,098,812 $14,369,055 $56,467,867 $13,308,399 $5,118,615

Baghouse 7 & 9 519,614 cfm

for 95% efficiency 22.6 $/cfm $16,280,794 $16,780,794 $19,801,337 $13,266,896 $33,068,233 $11,286,762 $44,354,995 $7,794,210 $2,598,070

for 90% efficiency 18 $/cfm $12,967,004 $13,467,004 $15,891,065 $10,647,013 $26,538,078 $9,057,907 $35,595,985 $7,274,596 $2,598,070

for 85% efficiency 14.7 $/cfm $10,589,720 $11,089,720 $13,085,870 $8,767,533 $21,853,402 $7,458,946 $29,312,348 $6,754,982 $2,598,070

Baghouse 8 76,274 cfm

for 95% efficiency 22.6 $/cfm $2,389,853 $2,889,853 $3,410,027 $2,284,718 $5,694,745 $1,943,715 $7,638,460 $1,144,110 $381,370

for 90% efficiency 18 $/cfm $1,903,423 $2,403,423 $2,836,039 $1,900,146 $4,736,185 $1,616,542 $6,352,728 $1,067,836 $381,370

for 85% efficiency 14.7 $/cfm $1,554,462 $2,054,462 $2,424,265 $1,624,258 $4,048,523 $1,381,831 $5,430,354 $991,562 $381,370

WESP Auxiliary $ 500,000

1998 389.5 Multiplier

2010 540 1.386393

2008 575.4