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MEMORANDUM

To: Chuck French, U.S. Environmental Protection Agency, OAQPS

From: Mike Burr, Donna Lazzari, and Danny Greene, ERG 

Date: April 2011

Subject: Draft Summary of the Technology Review for the Secondary Lead Smelting 

Source Category

This memorandum summarizes the results of an analysis to identify developments in 

practices, processes, and control technologies for emissions sources of hazardous air pollutants 

(HAP) from the Secondary Lead Smelting source category. This analysis is part of EPA’s 

review efforts in accordance with section 112(d)(6) of the Clean Air Act (CAA). This 

memorandum is organized as follows:

1.0 Background

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

1.2 Description of the Secondary Lead Smelting Source Category and

Requirements of the Current NESHAP

2.0 Developments in Practices, Processes and Control Technologies

2.1 Stack Emissions

2.2 Fugitive Emissions

3.0 Recommended Revisions Based on Developments in Practices, Processes and 

Control Technologies

3.1 Stack Emissions

3.2 Fugitive Emissions

4.0 Conclusions

1.0 BACKGROUND

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

Section 112 of the CAA requires EPA to establish technology-based standards for 

sources of HAP. These technology-based standards are often referred to as maximum achievable 

control technology, or MACT, standards. Section 112 also contains provisions requiring EPA to 

periodically revisit these standards. Specifically, paragraph 112(d)(6) states:
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(6) REVIEW AND REVISION. – The Administrator shall review, and revise as 

necessary (taking into account developments in practices, processes, and control 

technologies), emissions standards promulgated under this section no less often 

than every 8 years.

1.2 Description of the Secondary Lead Smelting Source Category and Requirements of 

the Current NESHAP

The current National Emissions Standards for Hazardous Air Pollutants (NESHAP) for 

the Secondary Lead Smelting source category was promulgated on June 13, 1997 (62 FR 32216) 

and codified at 40 CFR part 63, subpart X. As promulgated in 1997, the NESHAP applies to 

affected sources of HAP emissions at secondary lead smelters. The current NESHAP (40 CFR 

63.542) defines “secondary lead smelters” as “any facility at which lead-bearing scrap material, 

primarily, but not limited to, lead-acid batteries, is recycled into elemental lead or lead alloys by 

smelting.” The secondary lead smelting process consists of: (1) pre-processing of lead bearing 

materials, (2) melting lead metal and reducing lead compounds to lead metal in the smelting 

furnace, and (3) refining and alloying the lead to customer specifications. The NESHAP for the 

Secondary Lead Smelting source category does not apply to primary lead smelters, lead 

remelters, or lead refiners. 

Today, there are 14 secondary lead smelting facilities that are subject to the NESHAP. 

No new secondary lead smelters have been built in the last 20 years, and no new secondary lead 

smelting facilities are anticipated in the foreseeable future, although one facility is currently in 

the process of expanding their operations. 

HAP are emitted from secondary lead smelting as stack releases (i.e., process emissions, 

and process fugitive emissions) and fugitive dust emissions. Process emissions include exhaust 

gases from feed dryers and from blast, reverberatory, rotary, and electric furnaces. The HAP in 

process emissions are comprised primarily of metals (mostly lead compounds, but also some 

arsenic, cadmium, and other metals) and also may include organic compounds that result from

incomplete combustion of coke that is charged to the smelting furnaces as a fuel or fluxing agent, 

combustion of natural gas or other fuels, or combustion of small amounts of plastics or other 

materials that get fed into the furnaces along with the lead-bearing materials. Process fugitive 

emissions are released from various sources throughout the smelting process, including smelting 

furnace charging and tapping points, refining kettles, agglomerating furnace product taps, and 

drying kiln transition equipment. Process fugitive emissions are comprised primarily of metal 

HAP. Fugitive dust emissions are emissions that are not associated with a specific process or 

process fugitive vent or stack. Process fugitive emissions are comprised of metal HAP and result 
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from the entrainment of HAP in ambient air due to material handling activities, vehicle traffic, 

wind, and other activities. 

The current NESHAP applies to process emissions from blast, reverberatory, rotary, and 

electric smelting furnaces, agglomerating furnaces, and dryers; process fugitive emissions from

smelting furnace charging points, smelting furnace lead and slag taps, refining kettles, 

agglomerating furnace product taps, and dryer transition equipment; and fugitive dust emissions

from roadways, battery breaking areas, furnace charging and tapping areas, refining and casting 

areas, and material storage areas. For process sources, the current NESHAP specifies numerical 

emissions limits for total hydrocarbons (THC) and lead compounds for blast furnaces and 

collocated blast and reverberatory furnaces. Additionally, emissions limits for lead are specified 

for reverberatory, electric, and rotary furnaces. Lead compound emissions from all smelting 

furnace configurations are limited to an outlet concentration of 2.0 milligrams per dry standard 

cubic meter (mg/dscm) (0.00087 grains per dry standard cubic foot (gr/dscf)) (40 CFR 

63.543(a)). THC emissions from collocated blast and reverberatory furnaces are limited to an 

outlet concentration of 20 parts per million volume (ppmv) (expressed as propane) corrected to 4 

percent carbon dioxide (CO2). THC emissions are limited to 360 ppmv (as propane) at 4 percent 

CO2 from existing blast furnaces and 70 ppmv (as propane) at 4 percent CO2 from new blast 

furnaces (40 CFR 63.543(c)). The current NESHAP does not specify limits for THC emissions 

from reverberatory furnaces not collocated with blast furnaces, rotary furnaces, or electric 

furnaces. 

The current NESHAP requires that process fugitive emissions sources be equipped with 

an enclosure hood meeting minimum face velocity requirements or be located in a total enclosure 

subject to general ventilation that maintains the building at negative pressure (40 CFR 

63.543(b)). Ventilation air from the enclosure hoods and total enclosures are required to be 

conveyed to a control device. Lead emissions from these control devices are limited to 2.0 

mg/dscm (0.00087 gr/dscf) (40 CFR 63.544(c)). Lead emissions from all dryer emissions vents 

and agglomerating furnace vents are limited to 2.0 mg/dscm (0.00087 gr/dscf) (40 CFR 

63.544(d)). The current NESHAP also requires the use of bag leak detection systems for 

continuous monitoring of baghouses in cases where a high efficiency particulate air (HEPA) 

filter are not used in series with a baghouse (40 CFR 63.548(c)(9)).

For fugitive dust sources, the current NESHAP requires that facilities develop and 

operate according to a standard operating procedures (SOP) manual that describes, in detail, the 

measures used to control fugitive dust emissions from plant roadways, battery breaking areas, 

furnace areas, refining and casting areas, and material storage and handling areas.
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2.0 DEVELOPMENTS IN PRACTICES, PROCESSES, AND CONTROL 

TECHNOLOGIES

For the purposes of this technology review, a “development” was considered to be a (n): 

add-on control technology or other equipment that was not identified during the 

development of the current NESHAP for the source category; 

improvement in add-on control technology or other equipment that was identified 

and considered during development of the current NESHAP for the source 

category that could result in significant additional HAP emissions reductions; 

work practice or operational procedure that was not identified during development 

of the current NESHAP for the source category; or

applicable process change or pollution prevention alternative that was not 

identified and considered during the development of the current NESHAP for the 

source category. 

We investigated developments in practices, processes, and control technologies for three 

categories of HAP emissions sources from secondary lead smelters: (1) stack emissions of lead 

and other metal HAP, (2) stack emissions of organic HAP, and (3) fugitive emissions of lead and 

other metal HAP. To identify developments, we conducted searches of EPA’s 

RACT/BACT/LAER (Reasonably Achievable Control Technology/Best Available Control 

Technology/Lowest Achievable Emissions Rate) clearinghouse and the Internet for information 

on secondary lead smelting and similar processes, examined the Section 114 information 

collection request (ICR) responses from the 14 secondary lead smelting facilities, reviewed 

technologies employed by similar industries, and reviewed new or updated NESHAPs for other 

source categories. The results of these analyses are presented in the following sections.

2.1 Stack Emissions

The current NESHAP specifies emissions limits for metal HAP (using lead as a 

surrogate) and organic compounds (using THC as a surrogate) from stacks. This section of the 

technology review will focus on developments in practices, processes, and control technologies 

applicable to emissions of metal HAP and organic compounds from stacks.

a. Metal Hap Emissions from Stacks

Based on a review of the ICR responses, the most common control technology employed 

by the industry to control emissions of metal HAP from stacks is fabric filtration (or baghouses). 

Several types of baghouses are currently used by the industry, including shaker, pulse jet, and 

reverse pulse jet bag filters. One facility uses a wet electrostatic precipitator (WESP) 

downstream of a baghouse to further reduce emissions of metal HAP from stacks. Two other 

facilities have plans to install similar WESP units. Several facilities also reported using HEPA

filters as an add-on control downstream of their baghouses. Additionally, some facilities 

reported using cartridge collectors; however these types of controls are generally suited to reduce 
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metal HAP emissions from sources that have lower inlet concentrations and are typically not 

used to control metal HAP in smelting furnace exhaust.

The first part of our analysis included attempting to determine which control technology 

(e.g., fabric filter, WESP, HEPA filter, cartridge collectors) achieves the greatest control 

efficiency for metal HAP. We could not directly calculate control efficiencies due to lack of 

inlet concentration data; however, we compared the outlet lead concentrations from the different 

control technologies based on emissions data that we received in the ICR. 

As displayed in Figure 2-1, the average stack outlet lead concentration from the baghouse 

and WESP combination was almost 50 times lower than the outlet concentration achieved by 

using baghouses alone. HEPA filters used downstream of a baghouse achieved approximately 

20 percent lower outlet lead concentrations than baghouses alone. Cartridge collectors appear to 

achieve outlet lead concentrations approximately three times lower than baghouses; however, as 

mentioned, cartridge collectors are generally limited to emissions points with lower flow rates 

and inlet loading concentrations.

Figure 2-1. Comparison of Control Device Outlet Lead Concentrations from Different 

Technologies.

Based on emissions data received in the ICR, we also compared the relative performance 

of each baghouse across facilities and attempted to determine the factors that correlate best with 

low outlet lead concentrations. The factors that we considered include baghouse type (e.g.,

shaker, pulse jet, reverse bag pulse), filter material, and age of the unit. Figure 2-2 shows the 

results of these analyses. Based on our analysis, the most significant factor affecting baghouse 

performance is the age of the unit. We found that units installed prior to 1989 generally had 

significantly higher outlet lead concentrations than the newer units. Shaker baghouses appear to 

have higher outlet lead concentrations than those of the pulse jet or reverse bag pulse type. 

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Average Outlet Lead Concentration by Control Technology
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Figure 2-2. Comparison of Baghouse Outlet Lead Concentrations Based on Type (Upper Left), Filter Media (Upper Right), and 

Installation Year (Bottom).

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Average Outlet Lead Concentration from Baghouses by Type

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Average Outlet Lead Concentration from Baghouses by 

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Average Outlet Lead Concentrations from Baghouses by 

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However, the majority of the older units appear to be shaker types, and thus the age of the 

baghouse may be the controlling factor. We did not find a significant correlation between the 

outlet lead concentration and the filtration media used in the baghouses, although one company 

in the industry suggested, based on its experience, that Teflon (polytetrafluoroethylene) bags 

specifically supplied by Gore-Tex© performed better than other bag types. The company also 

suggested that the most critical factors influencing baghouse performance are proper installation 

and maintenance practices. They mentioned specific practices such as ensuring proper 

installation of the bags and properly sealing all ducts and dust conveyance devices. Additionally, 

they claim that replacing torn bags, rather than repairing them, can significantly improve 

baghouse performance.

Based on our analyses, we believe that the most important development in the control of 

stack emissions of metal HAP from this source category has been improvement in the 

performance of baghouses throughout the industry. The biggest indicator of such improvements 

is the level of metal HAP emissions currently being achieved in the industry in relation to the 

allowable level in the current NESHAP (referred to as “MACT-allowable”), which is a lead 

based concentration standard of 2.0 mg/dscm for all stacks. Figure 2-3 shows the lead 

concentrations reported by the industry in the ICR compared to the lead concentration limit in 

the current NESHAP. As illustrated by Figure 2-3, the outlet lead concentrations currently being 

achieved by the industry are far below, and in most cases orders of magnitude below, the 

concentration limit specified in the current NESHAP. The average reported stack lead 

concentration was 0.16 mg/dscm with a median of 0.04 mg/dscm. This large discrepancy 

between actual and MACT-allowable stack lead concentrations is likely a result of improvements 

in practices, processes, and control technologies that have significantly improved the 

performance of baghouses employed by this industry since the promulgation of the current 

NESHAP. We also believe that the concentration data presented in Figure 2-3 clearly show that 

improvements in baghouse technology and operation have occurred that resulted in the capability

of achieving significantly lower stack lead emissions than what is required by the current 

NESHAP.

b. Organic HAP and Dioxin and Furan Emissions

Based on our review of the ICR responses, we found that emissions of organic HAP from 

smelting furnaces vary substantially among the different furnace types. In general, emissions of 

organic HAP from blast furnaces are much higher than those from other furnace types. 

Information collected in the ICR indicates that this is likely due to the much lower exit 

temperature of the blast furnace exhaust relative to the other furnace types. The majority of 

facilities that operate blast furnaces use afterburners to control emissions of organic HAP. The 

exhaust of reverberatory furnaces is sufficiently hot that the use of an afterburner is generally not 
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required to meet the current THC limit. Some facilities that operate both blast and reverberatory 

furnaces comingle the hotter reverberatory furnace stream with the cooler blast furnace stream to 

control organics in the blast furnace stream. We did not identify new control technologies or 

developments in the mentioned existing control technologies that would achieve reductions in 

organic HAP emissions beyond the limits established in the current NESHAP.

Figure 2-3. Comparison of Stack Lead Concentrations Reported by the Industry with the Current 

MACT Standard.

Although dioxin and furan (D/F) emissions limits are not specified in the current 

NESHAP, we investigated technologies available for prevention and/or control of D/F emissions 

from the smelting furnaces. Based on data submitted by the industry in the ICR, D/F emissions 

from blast furnaces are one to three orders of magnitude higher than emissions from 

reverberatory and electric furnaces. The key conditions typically associated with higher D/F 

emissions, listed in order of relative importance1, are:

Poor combustion conditions,

High particulate concentration in the flue gases of a combustion process,

Increased residence time for particulate in critical temperature window (150 - 450 

degrees Celsius), 

Particulate matter containing metals that can catalyze formation to dioxin,

Waste or fuel that is comprised of complex organic or lignin-like structure, and

 

1 Gullett, Brian (EPA) and Seeker, Randy (EER Corporation), Chlorinated Dioxin and Furan Formation 

Control and Monitoring. Presentation at the Industrial Combustion Coordinated Rulemaking Meeting.

September 17, 1997.

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Sufficient chlorine.

We believe the controlling factor for D/F formation in blast furnaces is the relatively low 

exit temperature of the exhaust stream in comparison to other furnace types. 

We identified two technologies employed by this source category that have demonstrated 

effective control of D/F emissions from blast furnaces: (1) incineration of the furnace exhaust, 

and (2) comingling of the blast furnace exhaust with the hotter reverberatory furnace exhaust. 

Based on information submitted in the ICR and information in the literature on dioxin 

destruction efficiency, operating an afterburner at sufficient temperature (approximately 1,600 

degrees Fahrenheit) with adequate residence time (approximately 2.0-2.5 seconds) can achieve 

significant reductions in D/F emissions from blast furnaces2. Additionally, emissions data 

submitted in the ICR indicate that D/F emissions from collocated blast and reverberatory 

furnaces are generally lower than emissions from a blast furnace alone. Average exhaust D/F 

concentrations of the various furnace types are summarized in Table 2-1. 

Table 2-1. Summary of Exhaust D/F Concentrations by Furnace Type.

Furnace Type Average D/F 

(nanograms/dscm)

Reverberatory furnaces not collocated with blast furnaces, and reverberatory 

furnaces mixed with electric furnaces 0.10

Blast Furnaces 38.83

Collocated Blast and Reverberatory Furnaces 0.19

Rotary Furnaces 0.14

A review of technologies employed by other industries to control D/F emissions 

concluded that injecting activated carbon into the exhaust stream can also achieve significant 

reductions of D/F emissions; however, the costs associated with this technology for this source 

category were determined to be high (see Draft Cost Impacts of the Revised NESHAP for the 

Secondary Lead Smelting Source Category).

Because the presence of chlorine is necessary for D/F formation, we also examined the 

potential sources of chlorine in the feed materials charged to the smelting furnaces. Historically, 

the plastic battery casings used in the construction of automotive batteries contained polyvinyl 

chloride (PVC). Although battery casings are no longer made of PVC, the battery casings can 

sometimes contain small amounts of chlorinated flame retardants. This material may be 

introduced into the furnace through incomplete separation of the battery casing material from the 

 

2

Ficarella, Domenico and Laforgia, Domenico, Numerical Simulation of Flow-Field and Dioxins 

Chemistry for Incineration Plants and Experimental Investigation, Waste Management, 20 

(2000) 27-49. http://www.bvsde.paho.org/bvsacd/cd43/antonio.pdf
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lead-bearing material in the feed preparation process. Chlorine may also be present in the coke 

fed to the furnace as a fuel and reducing agent. Moreover, we believe that occasionally some 

older batteries that still contain PVC casings could be processed.

Based on our review, the main control of D/F emissions occurs due to measures initially 

implemented to control organic HAP emissions (i.e., incineration and co-mingling of furnace 

exhaust streams). We identified one other control technology with the potential to reduce D/F 

emissions (i.e., carbon injection); however, the costs to apply this technology were determined 

to be high.

2.2 Fugitive Emissions

As outlined in section 1.2 of this memorandum, the pollutants emitted from fugitive 

emissions sources in this source category are metal HAP. Therefore, we focused on identifying 

advancements in practices, processes, and control technologies related to fugitive emissions of 

metal HAP. Sources of fugitive emissions at secondary lead smelters include dust from plant 

roadways, battery breaking operations, material storage areas, and process fugitives that are not 

captured by a control device.

The minimum requirements for control of fugitive emissions in the current NESHAP for 

the following specified fugitive sources are:

Plant roadways – must be cleaned twice per day;

Battery breaking area – partial enclosure of storage piles and wet suppression with 

twice daily pavement cleaning;

Furnace and refining and casting areas – partial enclosure and pavement cleaning; 

and

Material Storage and Handling Areas – partial enclosure, wet suppression, and 

vehicle wash at exits.

Based on our analysis of information received in the ICR, we grouped the facilities into 

three categories that describe the level of fugitive emissions control implemented. Table 2-2 

defines these categories and Table 2-2 summarizes our categorization for each facility.

Table 2-2. Enclosure Category Definitions.

Enclosure Category Description

Level 1 Enclosure

Facilities described as having Level 1 enclosure meet the enclosure 

requirements in the current NESHAP. The facilities rely primarily on 

enclosure hoods to capture process fugitive emissions and partial 

enclosures with wet suppression for process units and storage areas.

Level 2 Enclosure

Facilities described as having Level 2 enclosure generally employ, in 

addition to enclosure hoods for process fugitive sources, a 

combination of negative pressure total enclosures and partial 

enclosures with wet suppression for process units and storage areas.
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Enclosure Category Description

Level 3 Enclosure

Facilities described as having Level 3 enclosure generally employ, in 

addition to enclosure hoods for process fugitive sources, negative 

pressure total enclosures for all process units and storage areas.

Table 2-3. Enclosure Category Assigned to the 14 Secondary Lead Smelting Facilities.

Facility Enclosure Category

Exide Technologies – Baton Rouge, LA Level 1

Exide Technologies – Forest City, MO Level 2

Exide Technologies – Frisco, TX Level 2

Exide Technologies – Muncie, IN Level 3

Exide Technologies – Reading, PA Level 2

Exide Technologies – Vernon, CA Level 3

Revere Smelting And Refining – Middletown, NY Level 3

Quemetco Inc. – Industry, CA Level 3

Quemetco Inc. – Indianapolis, IN Level 3

Sanders Lead Co. – Troy, AL Level 1

EnviroFocus Technologies – Tampa, FL Level 2

Gopher Resources – Eagan, MN Level 3

Buick Resource Recycling Facility – Boss, MO Level 1

East Penn Manufacturing – Lyons, PA Level 3

As displayed in Table 2-3, our analysis concludes that 11 of the 14 facilities are 

controlling fugitive emissions beyond the levels required by the current NESHAP. Additionally, 

seven of the 14 facilities have placed all of their process areas in total enclosures under negative 

pressure with ventilation to a control device. Furthermore, an 8th facility (EnviroFocus 

Technologies) has a current project to implement level 3 enclosure. Of the seven facilities that 

are currently level 3 enclosures, several facilities claimed performing additional work practices 

(beyond the enclosures) that exceed the requirements of the current NESHAP to further limit the 

formation of fugitive dust in other areas of their facilities. Examples of these work practices 

include:

more complete vehicle washing inside buildings;

improved roadway cleaning techniques and frequency;

pavement of entire facility grounds;

cleaning of building roofs and exteriors;
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use of daily ambient monitoring to diagnose plant activities that lead to 

exceedances of the National Ambient Air Quality Standards (NAAQS) for lead;

timely cleaning of accidental releases;

inspection of outside battery storage areas for broken batteries; and

performance of all maintenance activities inside total enclosures operated under 

negative pressure.

Our analysis of ambient lead concentration data measured near the facilities indicates that 

facilities with level 3 enclosure that implement the work practices described above are generally 

achieving much lower lead concentrations near their property boundaries (see Figure 3-2). For 

this reason, we believe that developments in practices, processes, and control technologies with 

regard to fugitive emissions of metal HAP have occurred that can result in reduced metal HAP 

emissions from fugitive sources beyond the standards contained in the current NESHAP.

3.0 RECOMMENDED REVISIONS BASED ON DEVELOPMENTS IN PRACTICES, 

PROCESSES, AND CONTROL TECHNOLOGIES

Based on the analyses presented above, we are recommending the following revisions to 

the current NESHAP with regards to stack and fugitive emissions from the Secondary Lead 

Smelting source category.

3.1 Stack Emissions

As described in section 2.1 of this memorandum, the concentrations of lead in stacks 

reported by this industry in the ICR are far below the level specified in the current NESHAP, 

indicating improvements in the control of metal HAP emissions since promulgation of the 

current NESHAP. Our analysis indicates that this is primarily a result of improved performance 

of baghouses. Therefore, we recommend revising the current NESHAP to reflect the level of 

performance currently being achieved by facilities that implement well-performing baghouses to 

control emissions of metal HAP from stacks.

When considering the most appropriate form of a revised lead standard for this source 

category, we considered alternatives to the current form (i.e., outlet lead concentration). 

However, our analysis indicates that a concentration-based lead standard continues to be the 

most appropriate form for this industry. We then attempted to determine the appropriate 

reduction to the current lead concentration limit of 2.0 mg/dscm. As outlined in section 2.1, the 

average stack concentration of lead reported by the industry in the ICR was 0.16 mg/dscm with a 

median concentration was 0.04 mg/dscm. Over 96 percent of the reported concentrations were 

less than half the current limit of 2.0 mg/dscm and over 80 percent of the reported concentrations 

were at least an order of magnitude less than the current limit. Our analyses conclude that 

advancements in the performance of baghouses appear to be the controlling factor for these 

lower concentrations and that reducing the current lead concentration limit from 2.0 to 0.2 
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mg/dscm would reflect the level of control achieved in practice by facilities that implement wellperforming baghouses.

Figure 3-1 compares the lead concentrations reported by the industry in the ICR with a 

potential revised lead concentration limit of 0.2 mg/dscm. Although the majority of stacks 

reported concentrations well below 0.2 mg/dscm, a limited number of stacks would need 

improvements, possibly in the form of improved maintenance practices on their existing 

baghouses or installation of newer, more efficient units. To provide the facilities flexibility in 

determining the best approach to meeting a revised concentration limit, we considered proposing 

a facility-wide flow-weighted average lead concentration limit of 0.2 mg/dscm. For this limit, 

facilities would assign a weighting factor to each stack lead concentration based on the flow rate 

of the stack. They would then sum the flow-weighted concentration of all the stacks at their 

facility to get a facility-wide flow-weighted concentration. A limit in this form would reflect the 

level of metal HAP emissions control being achieved in practice by well performing baghouses 

while providing flexibility to the facilities in determining the most cost-effective approach to 

achieving the necessary reductions. 

As required under section 112(d)(6), we considered the costs and other impacts associated with 

revising the lead concentration limit in the manner described above. As described in the Draft 

Cost Impacts of the Revised NESHAP for the Secondary Lead Smelting Source Category, we 

estimate that three baghouses at two facilities would need to be replaced as a result of the revised 

limit. The estimated total capital cost is $7.7 million with a total annualized cost of $1.7 million. 

We estimate that the revised limit would result in annual reductions of metal HAP of 

approximately 5.9 tons with co-reductions in emissions of particulate matter (PM) of 

approximately 56 tons. We do not anticipate additional energy use associated with this revised 

limit, as only replacement baghouses, as opposed to new additional units, are expected. 

Furthermore, we do not anticipate any adverse non-air environmental impacts associated with the 

implementation of this revised limit.

For these reasons, we are recommending that a flow-weighted average lead concentration 

limit of 0.2 mg/dscm be applied to the sum of all stacks at each facility in this source category. 

To limit the potential impacts of any individual stack, we are also recommending that a 

maximum lead concentration limit of 1.0 mg/dscm be applied to individual stacks in this source 

category. This is warranted given the fact that, as described above, over 96 percent of stack lead 

concentrations reported in the ICR were less than 1.0 mg/dscm.
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Figure 3-1. Comparison of Stack Lead Concentrations Reported by the Industry with a Potential 

Revised Lead Concentration Limit.

3.2 Fugitive Emissions

As outlined in section 2.2 of this memorandum, several facilities in this source category 

are currently implementing controls for fugitive emissions of metal HAP that exceed what is 

required in the current NESHAP. Based on our analyses, we are recommending revising the 

current NESHAP to reflect the level of control currently being achieved by the better performing 

facilities in this source category with regards to fugitive emissions of metal HAP.

Because fugitive emissions cannot be directly captured or measured, the most feasible 

limit is a work practice standard. Although lack of direct measurement makes comparisons of 

the efficiency of different control technologies challenging, analysis of ambient lead monitoring 

data near the facilities has generally been considered an accurate indicator of the level of fugitive 

emissions of metal HAP. The Draft Residual Risk Assessment for the Secondary Lead Smelting 

Source Category presents dispersion modeling results for this source category indicating that 

fugitive emissions are overwhelmingly the most significant source contributing to ambient lead 

concentrations near the property boundaries of secondary lead smelting facilities. The same 

modeling results indicate that fugitive lead emissions from this source category could result in 

exceedances of the lead NAAQS at 12 of the 14 facilities.

We analyzed available ambient monitoring data to determine which facilities were 

implementing the most effective controls for fugitive emissions of metal HAP. Figure 3-2 

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displays the annual average lead concentrations at ambient monitoring locations around facilities 

based on the enclosure category assigned to the facility in section 2.2 of this memorandum. The 

figure includes concentration data for 12 of the 14 facilities (monitoring data near Exide Baton 

Rouge and Exide Forest City were not available). All data in this figure were taken from 

http://www.epa.gov/airexplorer/monitor_kml.htm. The most recent year’s monitoring data 

available (either 2008 or 2009 for each facility) was selected for each facility. In cases where 

data were available at multiple monitoring locations around a facility, we chose the monitor with 

the highest annual lead concentration.

Figure 3-2. Comparison of Annual Ambient Lead Concentrations for Each Enclosure Category.

As the figure shows, facilities categorized as level 3 enclosures achieved significantly 

lower ambient lead concentrations than those classified as level 1 or 2 enclosures. As previously 

mentioned, seven of the 14 facilities are currently classified as level 3 enclosures, with an 8th

facility planning to implement level 3 enclosures in the near future. Of the facilities classified as 

having level 3 enclosures, four facilities also implement some or all of the additional work 

practices mentioned in section 2.2 to further prevent the formation of fugitive dust in other areas 

of their facilities. Based on this analysis, we concluded that level 3 enclosure plus the 

implementation of additional fugitive control work practices is necessary to achieve ambient lead 

concentrations below the NAAQS near the fence line of a facility. Because several facilities are 

already implementing these controls and because we estimate that these controls are necessary to 

ensure to ensure ambient lead concentrations below the NAAQS, we recommend revising the 

current NESHAP to require these controls.

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0.80

1.00

1.20

1.40

1.60

Level 1 Level 2 Level 3

Concentration (mg/dscm)

Annual Ambient Lead Concentrations by Enclosure Category
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As with the revised stack lead concentration limit discussed in section 3.1 of this 

memorandum, we considered the potential cost impacts of revising the fugitive emissions 

standard in the current NESHAP to include the controls mentioned above. As described in the 

Draft Cost Impacts of the Revised NESHAP for the Secondary Lead Smelting Source Category, 

we estimate that the total capital cost to implement level 3 enclosure and additional fugitive 

control work practices throughout the industry is approximately $40 million with a total 

annualized cost of approximately $9.6 million. We estimate reductions in metal HAP emissions 

of 9.5 tons per year resulting from this revised standard with co-reductions of PM of 

approximately 104 tons. We do not anticipate any adverse non-air environmental impacts 

associated with this recommended standard. However, we do anticipate some additional energy 

use associated with the operation of the new total enclosure. After consideration of the costs, 

emissions reductions, and other potential impacts, we believe the revision of the fugitive 

emissions standard for this source category to include the control measures described in this 

memorandum is warranted and necessary.

As an alternative to requiring level 3 enclosure and the implementation of an extensive 

list of fugitive control work practices, we recommend that facilities be allowed to demonstrate 

compliance through ambient lead monitoring. If facilities are able to demonstrate ambient lead 

concentrations near their facility that are below the lead NAAQS using practices other than those 

specified above, then it can be concluded that they are achieving a similar level of control as 

would be achieved by the control measures described in this memorandum. Providing such an 

alternative would allow the facilities flexibility in determining the most appropriate and costeffective method of achieving the necessary reductions in fugitive emissions of metal HAP.

4.0 CONCLUSIONS

This review identified several developments in practices, processes, or control 

technologies that have been implemented in this source category since promulgation of the 

current NESHAP. Our analysis indicates that several facilities have significantly reduced stack 

emissions of metal HAP, primarily though improved performance of baghouses. Additionally, 

several facilities have implemented fugitive emissions control practices that exceed the 

requirements of the current NESHAP. Based on our review, we conclude that it is feasible and 

cost-effective for facilities to achieve a facility-wide, flow-weighted average lead concentration 

of 0.2 mg/dscm with a limit of 1.0 mg/dscm for any individual stack. We conclude that it is 

feasible for all facilities to fully enclose all process areas under negative pressure of and 

implement a prescribed list of work practices to limit fugitive emissions. As an alternative, 

facilities could demonstrate a similar level of control for fugitive emissions by monitoring 

ambient lead concentrations at or near the facility boundaries to ensure that concentrations 

remain below the lead NAAQS (i.e., 0.15 μg/m3). Implementing these controls would achieve 
17

reductions in lead emissions of approximately 13.3 tons with total metal HAP reductions of 

approximately 15 tons. Additionally, we expect total co-reductions of PM emissions of 

approximately 160 tons. We estimate that between 48 and 76 tons of the total PM reductions 

will be reductions in particles with diameters less than 2.5 microns (PM2.5), depending on the 

nature of the particle size distribution of emissions from this source category. For these reasons, 

we believe that these controls and measures are cost-effective measures that reflect achievable 

performance for this industry.