1

MISSOURI

EPA’s Area Designations for the 

2008 Lead National Ambient Air Quality Standards

Introduction

EPA has revised the level of the primary (health-based) standard from 1.5 micrograms per cubic 

meter (μg/m3) to 0.15 μg/m3 measured as total suspended particles (TSP). EPA has revised the 

secondary (welfare-based) standard to be identical in all respects to the primary standard.

Pursuant to section 107(d) of the Clean Air Act, EPA must designate as “nonattainment”

those areas that violate the NAAQS and those nearby areas that contribute to violations. 

The table below identifies the counties or portions of counties in Missouri that EPA intends to 

designate “nonattainment” for the 2008 lead national ambient air quality standard (2008 Lead 

NAAQS). 

Table 1. Missouri Lead NAAQS Nonattainment Areas

Area

Missouri

Recommended 

Nonattainment 

Counties

EPA’s Designated 

Nonattainment 

Counties

Nonattainment 

area for 1978 Lead 

NAAQS

Jefferson County Jefferson County

(partial) 

Jefferson County

(partial)

City Limits of 

Herculaneum

Iron County Iron, Dent, and 

Reynolds (partial)

Iron, Dent, and 

Reynolds (partial)

None*

* Portions of western Iron County identified as Maintenance Areas

Within one year of a new NAAQS rulemaking, Section 107(d)(1) of the Clean Air Act requires 

the Governor of each state to submit to the EPA a list of all areas (or portions thereof) 

designating those areas as nonattainment, attainment or unclassifiable. Further, EPA is required 

to designate all areas (or portions thereof) no later than two years following the new NAAQS 

rulemaking. However, the period of time EPA has to promulgate the designations may be 

extended by one year if insufficient information exists to make the designations. In the Federal 

Register notice for the final lead NAAQS rule, EPA recognized that the existing lead monitoring 

network is insufficient to evaluate attainment for the new NAAQS at locations consistent with 

EPA’s proposed new monitoring network siting criteria and data collection requirements. Many 

new ambient lead monitors only began operation in January 2010. Therefore, EPA intends to 

designate nonattainment areas, those with existing violating monitors, in October 2010. In the 

designations due in October 2011, EPA will promulgate designations for areas not designated by 

this action.
2

Technical Analysis

The following technical analysis includes the Missouri counties of Jefferson, Iron, Dent and 

Reynolds. The Doe Run Company’s (Doe Run’s) Herculaneum primary lead smelter facility is 

the source in the Jefferson County nonattainment area, and its Buick secondary smelter and 

Buick mining and milling facilities are the sources in the Iron County nonattainment area which 

extends to portions of Dent County to the west and Reynolds County to the south. Jefferson and 

Iron Counties in the state of Missouri both contain monitors that violate the 2008 Lead NAAQS. 

Nearby counties or other potential sources for contributions to lead concentrations in the 

nonattainment area were also considered. EPA has evaluated these counties based on the weight 

of evidence of the following factors recommended in previous EPA guidance: 

 Air quality in potentially included versus excluded areas;

 Emissions and emissions-related data in areas potentially included versus excluded from 

the nonattainment area, including population data, growth patterns, and emissions 

controls;

 Meteorology (weather/transport patterns);

 Geography/topography (mountain ranges or other air basin boundaries);

 Jurisdictional boundaries (e.g., counties, air districts, reservations, etc.); and

 Any other relevant information submitted to or collected by EPA.

Jefferson County, Missouri Nonattainment Area

The Doe Run Herculaneum facility is currently the only operating primary lead smelter in the 

U.S. The facility has been in operation since 1892. The city of Herculaneum is currently 

designated nonattainment for the 1978 NAAQS. Figure 1 is a map of the area analyzed 

depicting the location and design value of air quality monitors. 

For each revision to a NAAQS EPA is required to conduct a separate designation action, which 

may result in the same or a different nonattainment boundary.

On December 28, 2009, the State of Missouri recommended that a portion of Jefferson County, 

Missouri, identified in Figure 1, be designated as “nonattainment” and that two other portions be 

designated “unclassifiable” for the 2008 Lead NAAQS based on air quality data from 2007 

through 2009. The state’s recommendation1 was based on data from Federal Reference Method 

(FRM) or Federal Equivalent Method (FEM) monitors located in Jefferson County and its 

evaluation of boundary considerations (e.g., modeling, historic data, interpolation, etc.). 

 

1

 Letter from Mark Templeton, Director, Missouri Department of Natural Resources, to William Rice, Acting 

Regional Administrator, U. S. Environmental Protection Agency, Region VII, dated December 28, 2009.
3

Figure 1. Herculaneum (Jefferson County, MO)

Recommended boundary is the area within the Herculaneum city limits (as the city limits are defined when this document is adopted on December 3, 2009) 

* Sources that are not labeled emitted 

less than 0.05 tpy.
4

Based on currently available information and EPA's technical analysis described below, EPA is 

designating a portion of Jefferson County as nonattainment for the 2008 Lead NAAQS. The 

EPA designated nonattainment area for the 2008 NAAQS depicted in Figure 1 is the same area

as previously designated for the 1978 Lead NAAQS.

Due to uncertainties in the currently available information discussed in the technical analysis 

below, EPA believes there is insufficient information on which to base a designation for the 

remainder of the county and intends to allow additional time to collect and evaluate data to 

demonstrate that violations are not occurring in these excluded portions of Jefferson County. 

Depending on the outcome of the additional data collection, EPA may in October 2011 extend 

the nonattainment boundary as appropriate. 

1. Air Quality Data 

This factor considers the lead design values (in μg/m3) for air quality monitors in Jefferson 

County at the Herculaneum primary smelter and in the surrounding area based on data for the 

2007 to 2009 period. A monitor’s design value is the highest three-month average over a three 

year period; in this case, 2007 through 2009. The design value determines whether that monitor 

attains a specified air quality standard. The 2008 Lead NAAQS is met at a monitoring site when 

the identified design value is valid and less than or equal to 0.15 μg/m3. A lead design value that 

meets the NAAQS is generally considered valid if it encompasses 36 consecutive valid threemonth site means (specifically, for a three-year calendar period and the two previous months). A 

design value is only valid if data collection, quality assurance/quality control (QA/QC), monitor 

siting, and minimum data completeness criteria specified in 40 CFR Part 58 are met. 

The 2009 Lead NAAQS design values for the Jefferson County nonattainment area are shown in 

Table 2.

Table 2. Air Quality Data

County State 

Recommended

Nonattainment?

Monitor Name1 Monitor Air 

Quality 

System ID

Monitor Location Lead Design 

Value,

2007-2009

(μg/m3) 2

Jefferson 

County

(Herculaneum)

Yes (partial) Bluff 29-099-0011 38.26744, -90.37403 0.85

Broad St 29-099-0015 38.26182, -90.37867 2.89

Circle St 29-099-0021 38.26516, -90.37733 1.32

Dunklin HS 29-099-0005 38.26728, -90.37912 0.73

Main St2

29-099-0004 38.26332, -90.37822 2.01

1

 Monitors owned and operated by MDNR

2

 High values in 2007 and 2008 established the design values for the MDNR monitors 

 

2

 It should be noted that the Main Street monitor records the highest concentrations for the ambient monitoring 

locations as the Broad Street monitor is no longer an ambient monitor for purposes of determining compliance with 

the 2008 Lead NAAQS since it is currently within Doe Run’s fenceline.
5

Figure 2. Herculaneum Ambient Air Monitor Locations
6

Monitoring data from the five monitors operated by MDNR in the vicinity of the Herculaneum 

primary smelter show a violation of the 2008 Lead NAAQS as shown in Table 2 above. There 

are five additional air monitors operated by Doe Run that also show violations; the Doe Run

monitoring results are comparable with the MDNR sites. Because Jefferson County contains at 

least one ambient monitor that has a Lead Design Value that is above 0.15 μg/m3, the boundary

of the nonattainment area is presumed to be the county.

Figure 2 depicts all air monitoring locations from 1995 to the present in the vicinity of the 

Herculaneum primary smelter. Historic air monitoring results from 1995 to the present indicate 

that State Implementation Plan (SIP) control strategies at the Herculaneum facility implemented 

in both 2001 and 2007 resulted in significant reductions in the ambient lead concentrations at 

these monitoring locations. The 2001 SIP plan included requirements to enclose process 

buildings, install ventilation systems that filtered gases through high-efficiency baghouse 

systems, work practice standards, process throughput restrictions and hours of operation 

limitations. The 2007 SIP3required extensive controls on material handling and delivery

systems, additional process controls and ventilation, and provides for the enforcement of the 

controls in the Work Practices Manual revision. Despite the controls implemented as a part of 

past SIP revisions, all of the existing monitors (pre-2010) owned and operated by MDNR within 

the Herculaneum city limits have recorded measurements exceeding the 2008 NAAQS.

In accordance with the Lead NAAQS Final Rule, the presumptive boundary is the entire county 

with a violating monitor. The State and/or EPA may conduct additional area-specific analyses 

that could lead to a departure from the presumptive boundary. 

Boundaries may be recommended on the basis of one or any combination of the following 

techniques in addition to the eight-factor analysis:

 Qualitative analysis;

 Spatial interpolation of air quality monitoring data; or

 Air quality simulation by dispersion modeling.

MDNR elected to use spatial interpolation of adjusted ambient air quality data and dispersion 

modeling for making its boundary recommendation to EPA. EPA evaluated MDNR’s analysis 

and conducted independent verification and analysis as discussed below.

In addition to the five MDNR air monitors located near the Herculaneum smelter facility, there 

were two ambient air monitors for lead located outside the Herculaneum city limits: Ursuline to 

the south; and Dow Pevely to the north. The Thurwell monitor was previously located to the 

northwest and the Golf Course monitor was located to the west of the Herculaneum facility, but 

within the city limits. These four monitors were discontinued in late 2005 because the results met 

the 1978 NAAQS which is 1.5 ug/m3. There are no monitoring data for areas outside the 

existing or state-recommended nonattainment boundary from late 2005 through the end of 2009; 

however, in January 2010, two monitors were established to replace the Dow-Pevely monitoring 

 

3

 “2007 Revision of the SIP for the Herculaneum Lead Nonattainment Area,” adopted by the Missouri Air 

Conservation Commission on April 26, 2007. EPA has proposed to approve the 2007 SIP for Herculaneum, but has 

not yet taken final action (FR52701). 
7

site to the north and one monitor was established to the south to replace the Ursuline monitor. 

Figure 3 depicts the locations of the Dow Pevely, Ursuline, Golf Course, Thurwell and Dunklin 

air monitors surrounding the Herculaneum facility.

In its TSD,4 MDNR used a ratio-based method to estimate the concentrations of lead at the

locations of the four monitors discontinued in 2005, two of which are located outside the existing 

nonattainment boundary, as a part of its technical analysis in support of the boundary

recommendation. The MDNR calculated the ratio of every three-month rolling average from 

2000 to 2005 for each discontinued monitor to those same averages at the Dunklin High School 

monitor. After examining the highest, lowest and average ratios for each discontinued monitor, 

MDNR chose to use the average plus one standard deviation as the factor to adjust the 

maximum three-month rolling average concentration from the Dunklin High School monitor 

after 2007 to approximate concentrations at the discontinued monitors for the same time period. 

More specifically, MDNR multiplied the average ratio plus one standard deviation for each of 

the four discontinued monitors by the highest post-2007 three-month rolling average 

concentration from the Dunklin High School monitor (i.e., 0.386 ug/m3) to provide 

approximations of the highest post-2007 concentrations for all four discontinued monitors. The 

estimation method used data from the Dunklin High School monitor to estimate post-2005 

monitoring results for the discontinued monitors because it is the most distant monitoring 

location from the source with continuous data. The results of this analysis are provided in Table 

3 below.

Table 3. Ratio-Adjusted Historic Monitoring Data for Interpolation

Dow-Pevely Golf Course Ursuline Thurwell

Max conc (2001) 0.560 0.506 0.251 0.3061

Max Ratio 0.7342 1.1078 0.4503 1.4629

Min Ratio 0.0524 0.0201 0.0185 0.2871

Avg Ratio 0.2268 0.2592 0.1290 0.8928

Std Dev 0.1319 0.2101 0.0793 0.4370

Avg + 1 Std Dev 0.3587 0.4693 0.2083 1.3298

Post-2007 H. S. Max 0.386 0.386 0.386 0.386

Ratio Adj 2007 Conc 0.139 0.181 0.081 0.514

Max 3-month

Rolling (post-2001)

0.192

(Feb – Apr 03)

0.232

(Dec 04 – Feb 05)

0.084

(Aug - Oct 02)

0.330

(Nov 04 - Jan 05)

1

 The Thurwell monitor was only operated in 2004 and 2005; the maximum concentration was detected in 2005.

The ratio-based approximations of post-2007 ambient lead concentrations highlighted in bold 

above, subject to the uncertainties discussed below, suggest compliance with the 2008 lead 

NAAQS for the two discontinued monitors outside the existing nonattainment boundary for 

Herculaneum. The ratio-based approximations of the Golf Course and Thurwell monitors 

 

4

 “Technical Support Document for Recommendation of Nonattainment Boundaries in Missouri for the 2008 Lead 

National Ambient Air Quality Standard,” Missouri Department of Natural Resources, Division of Environmental 

Quality, Air Pollution Control Program, December 3, 2009.
8

Figure 3. Location of Herculaneum Air Monitors used for Ratio-Based Estimation5

 

5 The data depicted in Figure 3 represent historic (pre-2005) monitoring results.
9

located within the EPA designated nonattainment boundary suggest possible violations of the 

2008 lead NAAQS. MDNR considers its ratio-based analysis to be conservative because the 

average plus one standard deviation and the highest recorded concentration from the Dunklin 

High School monitor after the 2007 state mandated controls were implemented; this value was 

recorded in February through April 2009.

The EPA conducted an independent analysis of the correlation of the monitoring data from the 

Dow-Pevely and Ursuline sites with the data collected from the Dunklin High School monitor 

utilizing daily values from 2000 - 2005. The Pevely monitor was the focus of the analysis 

because it is the only monitor outside the proposed nonattainment boundary reporting a violation 

of the 2008 NAAQS after 2001. The correlation coefficient (R) and the coefficient of 

determination (R2) were calculated to determine both how well the data correlate and how well 

the regression best fits the data. Data that correlate well will have an R value closer to 1.0, 

indicating unity or perfect correlation. For the coefficient of variation, the higher the R2values 

the greater the number of data points that are close to the best fit line, e.g., 1.0 indicates 100% of 

the data fit the regression. It should also be noted that the data set was evaluated to eliminate 

void, missing and/or extra data to ensure a valid comparison for specific dates at each site. 

Table 4. Analysis of Correlation (R) and Coefficient of Determination (R

2

) for Pevely and 

Dunklin High School Lead Monitoring Results from 2000 - 2005

Year Correlation (R) Coefficient of Determination (R

2

)

2000 0.72 0.52

2001 0.57 0.32

2002 0.35 0.12

2003 0.05 0.003

2004 0.35 0.12

2005 0.26 0.07

As the data in Table 4 above indicate, the correlation of the data from the Dow Pevely and 

Dunklin High School monitoring sites is not very strong. The correlation between the two data 

sets is most likely affected by meteorological conditions, particularly wind speed and direction, 

and emissions activity. 

MDNR provided further analysis using spatial interpolation of the ratio-based estimation of lead 

concentrations predicted to be measured in the Dow Pevely, Ursuline, Thurwell and Golf Course 

monitors. The spatial interpolation is depicted in Figure 4 below.

This analysis is subject to the uncertainties associated with the ratio-derived data, and additional 

uncertainties, such as whether the monitoring data used in the spatial interpolation which are the 

highest three-month concentrations since 2001, are representative of post-2007 ambient 

concentrations, and whether spatial interpolation can reasonably estimate air quality around the 

Doe Run facility. In particular, the large range observed between the minimum and maximum 

ratio at the Dow-Pevely site, along with the results of the correlation analysis, indicate the high 

degree of variability of lead concentrations between the two sites.
10

Figure 4. Interpolation of Herculaneum Monitoring Data
11

As discussed above, the four peripheral air monitors were discontinued after 2005 because these 

locations consistently monitored attainment with the 1978 NAAQS. In January 2010, MDNR 

resumed lead air monitoring at locations near the Pevely and Ursuline locations. Three new 

locations named “Pevely,” “Pevely North,” and “Ursuline North” replace the former monitoring 

locations. Preliminary data obtained from MDNR indicate that for the first three rolling calendar 

quarters of 2010 (January through May), all three of the new peripheral monitors are below the 

standard. The average concentration of ambient lead measured in the Ursuline North monitor 

ranged from 0.033 to 0.066 ug/m3, the average concentrations from the Pevely North monitor 

ranged from 0.023 to 0.030 ug/m3, and the average concentrations from the Pevely monitor 

ranged from 0.023 to 0.046 ug/m3. It should be noted that the Pevely, Pevely North and 

Ursuline North monitors are “neighborhood scale” monitors which monitor an area between 0.5 

and 4 kilometers (km). Uncertainties associated with the use of the 2010 monitoring data include 

the temporal limits of the data, as only three rolling quarters of data have been collected thus far. 

Also, the data were collected during the winter and spring months in which the predominant 

wind direction was from the north, which likely would result in lower concentrations in the 

Pevely and Pevely North monitors and higher in the Ursuline North monitor. The Agency will 

continue to evaluate new data as it becomes available.

In addition to ratio-derived estimation and spatial interpolation of the monitoring data, MDNR 

also conducted extensive dispersion modeling of ambient lead concentrations presented in Figure 

5. The city limits of Herculaneum, the existing nonattainment boundary for the 1978 NAAQS, 

are depicted in blue; the orange blocks are incorporated areas of Pevely to the north and Festus 

and Crystal City to the south. The blocks represent a mixture of sections that are identified by 

township, range and section, and historic land grant areas. The dots on the figure denote the 

receptor grid used in the model, with each receptor color-coded according to the concentrations 

of lead predicted. 

MDNR used AERMOD, EPA’s preferred dispersion model for the analysis conducted. The 

modeling was performed for the time period of 2007 – 2009 using maximum production rates for 

the Herculaneum smelter. It included on-site meteorological data for ground-level analyses, and 

data from the airport in Lincoln, Illinois for the upper atmospheric meteorological analyses. All 

of the meteorological data were quality-assured. Fugitive emissions from haul route traffic and 

buildings were included in the model. EPA conducted an independent review of MDNR’s 

model6and determined that while there are some areas for improvement, the modeling effort was 

comprehensive and done in accordance with EPA modeling guidance.

Violations of the NAAQS were predicted in all directions from the facility with the highest 

estimated concentrations adjacent to the facility. There is a sharp decrease in the lead 

concentrations as the distance from the facility increases, as would be predicted based on the 

physical properties of lead. The model predicts potential violations of the 2008 NAAQS outside 

the existing and state recommended nonattainment boundary. While it is acceptable to use 

modeled lead concentrations as one component of the analysis to determine the boundaries of the 

Jefferson County nonattainment area, one significant uncertainty with the modeling conducted 

by the State is the use of maximum allowable production levels under MDNR’s 2007 SIP

 

6

 Memorandum from Richard Daye, EPA, to Stephanie Doolan, EPA, dated April 30, 2010, re: Modeling Review 

of Doe Run Herculaneum and Buick/Viburnum, Missouri Areas.
12

Figure 5. Herculaneum Modeled Lead Concentrations
13

revision3rather than actual operating conditions. The modeled emissions were 158.66 TPY; 

whereas, the average actual emissions from 2007 - 2009 are 18.33 TPY (see Table 6 below). 

2. Emissions and Emissions-Related Data

Evidence of lead emissions sources surrounding a violating monitor are an important factor for 

determining whether a nearby area is contributing to a monitored violation. For this factor, EPA 

evaluated county level emission data for lead and population data.

Emissions data that appear on Figure 1 and in Table 5 below were derived from the 2002 

National Air Toxics Assessment (http://www.epa.gov/ttn/atw/natamain/). EPA recognizes that 

for certain sources, emissions may have changed significantly since 2002. For example, certain 

large sources of emissions in or near this area may have installed emission controls or otherwise 

significantly reduced emissions since 2002. Figure 1 indicates two facilities in Pevely, Missouri, 

reporting lead emissions. The facility to the northwest of Herculaneum reporting lead emissions 

of 0.2 TPY is Saint Gobain Container, and the facility to the east of it identified in the legend on 

Figure 1 as reporting less than 0.2 tons per year (TPY) lead emissions is Alcoa Composition. 

EPA verified emissions reported for these facilities with the 2007-2009 state emissions 

inventory (MoEIS). These facilities are approximately 1.5 miles from the violating monitor in 

Jefferson County. Neither of these facilities is believed to be influencing the monitors due to 

their distance and the quantity of emissions reported relative to the quantity of the emissions 

from and the proximity of the Herculaneum facility to the monitor. As a result, neither Alcoa 

nor Saint Gobain were considered further in this technical analysis. 

There are approximately 20,000 airport facilities in the U.S. at which leaded aviation gasoline is 

consumed. Piston-engine propeller type airplanes use the lead aviation gasoline, so EPA and 

MDNR considered the potential for the Festus Memorial Airport to impact the Herculaneum 

nonattainment area. Based on the airport’s distance, 4 miles to the south, and the reported 

emissions, 40 pounds (lbs) of lead for 2008, EPA does not believe that Festus Memorial Airport 

contributes to the nonattainment area. Note that there are two airplane symbols on Figure 1; one 

is for Festus Memorial Airport and the second is for an associated heliport.

Table 5 shows total emissions of lead (given in TPY) for violating and potentially contributing 

counties in and around the Herculaneum nonattainment area and sources emitting greater than 

0.5 ton per year of lead according to the 2002 NATA and 2007-2009 MoEIS. Based on the 2002 

NATA and MoEIS, there are no other sources of lead emissions either within or outside 

Jefferson County that are contributing to the nonattainment area for the 2008 Lead NAAQS. 
14

Table 5. Lead Emissions

County

Facility in State

Recommended 

Nonattainment

Area?

Facility – Total 

Air Emissions 1

(tons per year)

Facility Total County Lead 

Emissions

(tons per year)

Jefferson 

County Yes

41.11 Herculaneum

Primary 

Smelter

41.3

Jefferson 

County No 0.2 Saint Gobain Container

41.3

Jefferson 

County No <0.2 Alcoa Composition

41.3

1

– National Air Toxics Assessment (NATA) 2002

For comparison, EPA reviewed the emissions inventory information reported by Doe Run for 

years 2000 – 2002 in its responses to the State’s Emission Inventory Questionnaires. 

Information for 2003 – 2009 is from MDNR’s MoEIS database. The emissions data are 

presented to examine the trends in emissions in comparison with the historic monitoring data 

discussed above. As Table 6 indicates, the lead emissions from the Herculaneum smelter have 

decreased significantly from 2000 – 2009, corresponding with but proportionately larger than the 

significant decrease in lead production. 

Table 6. Herculaneum Smelter Production

Year Lead Production (TPY) Lead Emissions TPY1,2

2000 243,516 125.81

2001 203,262 110. 4

1

2002 143,265 58. 18

2003 150,550 25.12

2004 163,736 26.02

2005 154,969 28.12

2006 168,301 26.42

2007 136,573 21.812

2008 144,799 19.192

2009 114,298 13.992

1

- Emission Inventory Questionnaire reported by Doe Run Company

2- Emissions reported from MoEIS database
15

As a part of MDNR’s 2007 SIP revision3, modeling was conducted which forms the basis for the 

modeling used by MDNR in its TSD4for its boundary recommendation. In its modeling, MDNR 

used hourly emissions by department developed by Doe Run7. The hourly emissions study

calculated emissions originating from the facility’s lead concentrate unloading department, sinter 

plant, blast furnace (including main stack), drossing plant, and refinery strip rolling mill, 

including fugitive emissions from each of these departments. Fugitives from wind-blown 

erosion from storage piles and re-entrainment of dust from paved and unpaved haul routes were 

calculated as a separate category. Fugitive emissions from wind-blown erosion from storage 

piles and deposition/re-entrainment of lead-contaminated dust along haul routes represents 

approximately 7% of the total facility emissions. Due to the significance of this source of lead to 

the ambient air, it is important to note that the Jefferson County nonattainment area designation 

includes the main haul routes from the Herculaneum smelter facility to the city boundary.

3. Population Data

Table 7 shows the 2008 population for Jefferson County, Missouri, which includes the proposed 

Herculaneum nonattainment area. These data help assess the extent to which the concentration 

of human activities in the area and concentration of population-oriented commercial 

development may indicate emissions-based activity contributing to elevated ambient lead levels. 

This may include ambient lead contributions from activities that would resuspend lead that has 

been deposited on the ground or on other surfaces, such as fugitive emissions from the lead 

concentrate haul routes.

Table 7. Population Data

County State Recommended 

Nonattainment?

2008 

Population

2008

Population 

Density 

(pop/sq mi)

Population 

Change

2000-2008

Population 

% Change 

2000-2008

Jefferson Co., 

Missouri

Yes, partial 217,679 328 18,941 10

Source: U.S. Census Bureau estimates for 2008 (http://www.census.gov/popest/datasets.html) 

The areas surrounding the Herculaneum smelter are not more densely populated that surrounding 

areas such as Pevely, Crystal City and Festus. The area may be characterized as predominantly 

residential or light commercial/industrial. EPA does not believe that the population data 

provided in the analysis of this factor affect the boundary recommendation.

 

7

“2005 Hourly Lead Emission Inventory for Doe Run’s Herculaneum, Missouri Smelter,” Shell Engineering and 

Associates, Inc., February 1, 2007.
16

4. Growth Rates and Patterns 

This factor considers population growth for 2000-2008 in the area considered for the 

nonattainment designation. Table 8 below shows population, and population growth for 

Jefferson County, Missouri. All population data is from the U.S. Census Bureau 

http://www.census.gov/popest/counties/CO-EST2008-popchg2000_2008.html. 

Table 8. Population and Percent Change

Location 2008 Population 2008 Population Density

(pop/sq mi)

Population 

% change 

(2000 - 2008)

Absolute change in 

population

Jefferson County, 

Missouri

217,679 328 10 10%

Jefferson County, Missouri had a moderate population growth between 2000 and 2008. Growth 

in new residential housing and commercial/light industrial facilities is evident, particularly along 

the I-55 highway corridor. This is most likely due to proximity to St. Louis, Missouri. EPA has 

considered the population growth rate for this area and does not believe that it affects the 

boundary determination. 

5. Emissions Controls

Under this factor, the existing level of control of emission sources is taken into consideration. 

The emissions data used by EPA in this technical analysis and provided in Tables 5 and 6 above

represent emissions levels taking into account any control strategies implemented for the existing 

Herculaneum nonattainment area for the 1978 NAAQS. As discussed above, there were SIP 

mandated controls placed on the facility in 2001 and state-mandated controls in 2007 resulting in 

significant reductions in the Herculaneum smelter emissions, as demonstrated in Figure 6 below. 

Lead concentrations at the monitors are affected by the amount of lead produced and subsequent 

emissions from the Herculaneum smelter facility. While the 2001 (implemented in 2002) and 

2007 controls do not bring Jefferson County in attainment with the 2008 NAAQS, it is apparent 

that lead concentrations measured in the monitors close to the smelter facility are greatly

reduced. The other small lead sources in the area do not have regulatory controls for lead, but 

are not expected to be contributing to nonattainment in the area.
17

Figure 6. Ambient Lead Concentrations at Herculaneum, 1995 – 2009

6. Meteorology

For this factor, EPA considered data from National Weather Service instruments and other 

meteorological monitoring sites in the area. Wind direction data for the area are depicted in 

Figure 7 below. 

The three-dimensional bar chart below shows the wind frequencies in eight directions for the 

four seasons. The chart frequencies reflect the directions from which the winds come. Based on 

Figure 7, it may be concluded that the wind originates predominately from the WNW in the 

winter months and from the SSW during summer months. These meteorological conditions are 

typical of areas along the Mississippi River valley. As discussed above, on-site surface 

meteorological data were used in the lead concentration modeling analysis. There are lead air 

monitors located both north and south of the smelter facility, so regardless of the season, 

monitoring is expected to detect lead in the ambient air. The Jefferson County nonattainment 

boundary recommendation is supported by the meteorological data.

0.000

2.000

4.000

6.000

8.000

10.000

12.000

14.000

16.000

Mar-95

Sep-95

Mar-96

Sep-96

Mar-97

Sep-97

Mar-98

Sep-98

Mar-99

Sep-99

Mar-00

Sep-00

Mar-01

Sep-01

Mar-02

Sep-02

Mar-03

Sep-03

Mar-04

Sep-04

Mar-05

Sep-05

Mar-06

Sep-06

Mar-07

Sep-07

Mar-08

Sep-08

Mar-09

ug/m^3

End Month

Lead Concentration Data in Herculaneum, Missouri

(3-month Rolling Average)

Bluff

High School

Broad St.

2008 Standard

2001 SIP Controls 

Completed

2007 SIP Controls 

Completed
18

Figure 7. Herculaneum Historic Meteorological Data

Source: 1960-1992 Solar and Meteorological Surface Observation Network information issued jointly by the U.S. 

Department of Commerce: National Climatic Data Center and the U.S. Department of Energy: National Renewable 

Energy Laboratory

7. Geography/Topography

The geography/topography analysis evaluates the physical features of the land that might have an 

effect on the air shed and, therefore, on the distribution of lead over the proposed Herculaneum 

nonattainment area.

The Jefferson County nonattainment area lies in the Mississippi River valley which affects 

meteorological conditions, as discussed in Section 6 above. The area is characterized by wooded 

bluffs to the north and south of the facility, while the area west of the facility is residential with 

less topographic relief. To the east across the Mississippi River, the area is largely crop land 

with few houses. EPA believes that the geographical or topographical features of the area do not 

significantly limit air-pollution transport within its air shed, but rather that it creates a mild 

tunnel effect for winds originating from the north in winter and from the south in summer 

months. Therefore, this factor did not play a significant role in determining the nonattainment 

boundary.
19

8. Jurisdictional boundaries 

Existing jurisdictional boundaries may be helpful in articulating a boundary for purposes of 

nonattainment designations, and for purposes of carrying out the governmental responsibilities of 

planning for attainment of the lead NAAQS and implementing control measures. These existing 

boundaries may include an existing nonattainment or maintenance area boundary, a county or 

township boundary, a metropolitan area boundary, an air management district, or an urban 

planning boundary established for coordinating business development or transportation activities.

The city limits of Herculaneum, Missouri, is the jurisdictional boundary which defines the 

nonattainment area. Areas to the north include the incorporated limits of Pevely, and areas to the 

south include Festus and Crystal City. The orange lines on Figure 2 indicate a number of 

jurisdictional boundaries for the areas to the north and south of Herculaneum. These areas 

include townships, sections, and land grant designations. These jurisdictional boundaries were 

considered in determining the appropriate boundary. 

9. Other Relevant Information

EPA received additional information from the State relevant to establishing a nonattainment area 

boundary for this area. As discussed in Section 1, Air Quality, above, MDNR submitted 

modeling analysis and spatial interpolation of air monitoring data in support of its boundary

recommendation. EPA considered this information and conducted an independent analysis in 

making its boundary determination for the Herculaneum lead nonattainment area. 

Summary

EPA is designating as nonattainment that portion of Jefferson County Missouri which coincides 

with the Herculaneum city limits as identified in Figures 1 and 2 as the nonattainment area for 

the 2008 Lead NAAQS. The Herculaneum city limits include the same area previously 

designated as nonattainment for the 1978 Lead NAAQS.

Five air quality monitors operated by MDNR in Jefferson County surrounding Doe Run’s 

Herculaneum smelter facility show violations of the 2008 Lead NAAQS based on 2007 - 2009 

air quality data. Therefore, a nonattainment designation is required for all or some of Jefferson 

County. EPA has considered all eight factors and other relevant information submitted by

MDNR to help determine an appropriate boundary. Other relevant information considered 

includes ratio-derived estimation and spatial interpolation of historic monitoring values at 

locations of discontinued monitors north and south of the existing lead nonattainment area for the 

1978 NAAQS and dispersion modeling conducted by MDNR. In addition to the historic 

monitoring data, EPA considered preliminary data from January through March 2010 for three 

new monitors placed at the locations of the historic Dow Pevely monitor to the north and the 

Ursuline monitor to the south. 

The available monitoring data indicate that the existing nonattainment boundary for the 1978 

NAAQS captures the existing monitored violations. It also includes all the significant lead 

emitting facilities and activities within the county: the Doe Run primary smelting facilities and 
20

related operations. EPA has considered MDNR’s spatial interpolation and concludes that the 

uncertainties associated with this analysis are so significant that the interpolation does not 

provide a reliable basis for designations.

EPA has a high degree of confidence in the use of the dispersion model to characterize lead 

concentrations in ambient air. However, because the model inputs utilized maximum emissions

estimates at this facility, EPA believes the modeling results likely overestimate the extent of the 

2008 NAAQS violations, although EPA has very little information with which to judge the 

degree of overestimation. Also, as discussed in the text, EPA notes that there are uncertainties 

associated with the use and interpolation of the historic monitoring data from the peripheral 

monitoring sites. Given the uncertainty in the modeling results, EPA is relying more upon the 

monitoring data than the modeling to inform the boundary. 

In summary, considering all of the technical information presented, and placing greater emphasis 

on the monitoring data, EPA is designating as nonattainment the portion of Jefferson County

consistent with the Herculaneum city limits as the 2008 NAAQS nonattainment boundary. 

Based on its consideration of all the relevant, available information, as described above, EPA 

believes that the boundaries described herein encompass the entire area that does not meet (or 

that contributes to ambient air quality in a nearby area that does not meet) the 2008 Pb NAAQS. 

As discussed above, due to the uncertainty in the interpolated monitoring and modeling data for 

the areas outside the Herculaneum city limits, EPA intends to allow time to collect and evaluate 

additional data from the new monitoring sites, and conduct additional analyses, as appropriate. 

The area will be re-evaluated in the second round of designations taking into consideration all 

newly available data and information. 
21

Iron, Dent and Reynolds Counties, Missouri Nonattainment Area

As discussed in the Introduction, Doe Run also owns and operates the Buick secondary smelter 

facility near Bixby, Missouri in Iron County. The Buick facility initially began operation as a 

primary smelter in 1968. Since 1991, the Buick facility has operated as a secondary smelter for 

recycling lead, primarily from lead-acid storage batteries. Buick is also the only location in the 

U.S. for recycling lead from cathode ray tubes from televisions and computer monitors. 

In 1991, western Iron County was designated nonattainment, effective in 1992. In October 2000, 

western Iron County was redesignated as attaining the 1978 Lead NAAQS. In August 2004, the 

Buick facility’s maintenance plan was approved by EPA by final rulemaking. Iron County has 

been in attainment of the 1978 NAAQS until the fourth quarter of 2008. Following the 2008 

exceedences of the 1978 Lead NAAQS, contingency measures identified in the facility’s 

approved maintenance plan have been implemented. 

Doe Run also operates a number of mining and milling facilities in the vicinity of the Buick 

facility including the Buick, Brushy Creek, Fletcher and Sweetwater mines and mills. Figure 8

is a map of the area analyzed showing the location and design value of air quality monitors. 

These operations extend into portions of Iron, Dent and Reynolds Counties in Missouri. 

An additional source of lead emissions in Iron County is Doe Run’s Glover facility, a former 

primary smelter, where lead ore and zinc and copper concentrate handling activities are currently 

conducted. The Glover facility began operations in the 1970’s and is located in the southeastern 

portion of Iron County. It was designated nonattainment for the 1978 lead NAAQS in 1992 and 

ceased smelting operations in 2003, after which it has been in care and maintenance. Doe Run 

no longer has an operating permit to conduct pyro-processing at this facility. EPA designated 

eastern Iron County, the portion including the Glover facility, in October 2004 as attaining the 

1978 Lead NAAQS. Current monitoring data in the vicinity of Glover are below the new 

standard. The State has recommended the area surrounding the Glover facility for attainment of 

the 2008 Lead NAAQS. EPA is only designating areas with monitored violations, and will 

address all other areas in a second phase, scheduled to be completed in October 2011. The 

analysis below includes a discussion of the Glover facility’s lack of contribution to the violating 

monitors elsewhere in Iron County.

On December 28, 2009, the State of Missouri recommended that portions of western Iron, Dent 

and Reynolds Counties in Missouri, identified in Figures 8 and 9, be designated as 

“nonattainment” and “unclassifiable” for the 2008 Lead NAAQS based on air quality data from 

2007 through 2009. The state’s recommendation1 was based on analysis of monitoring and 

modeling data. 

Based on EPA's technical analysis described below, EPA is designating portions of Iron, Dent 

and Reynolds Counties as nonattainment for the 2008 Lead NAAQS, based upon currently 

available information. The area recommended by MDNR as “unclassifiable” on Figure 9 will be 

considered by EPA in its October 2011 designations.
22

Figure 8. Buick/Viburnum Trend (Dent, Iron & Reynolds Counties, MO) 

* Sources that are not labeled emitted 

less than 0.05 tpy.
23

Figure 9. Iron, Dent & Reynolds County Lead Nonattainment Recommendation
24

1. Air Quality Data 

This factor considers the Lead Design Values (in μg/m3) for air quality monitors in western Iron 

County at the Buick secondary smelter and in the surrounding area, and southeastern Iron 

County around the Glover facility, based on data from 2007-2009. The monitors used for 

determining compliance with the regulatory standard are FRM or FEM monitors located in Iron 

County. As discussed above, a monitor’s design value indicates whether that monitor attains a 

specified air quality standard; in this case the 2008 lead NAAQS. 

The 2009 Lead NAAQS Design Values for the monitors in Iron County and surrounding area are 

shown in Table 9.

Table 9. Iron, Dent and Reynolds Counties Air Quality Data

County State

Recommended

Nonattainment?

Monitor Name Lead Design Value,

2007-2009

(μg/m3)

Iron, Dent & Reynolds Yes (partial) Buick South 2.46

Iron No Post Office 0.13

Iron County, Missouri shows a violation of the 2008 Lead NAAQS for the monitor listed in 

Table 9 above in the vicinity of the Buick smelter, mine and milling operations. Because the 

county contains at least one ambient monitor that has a Lead Design Value that is above 0.15 

μg/m3, the boundary of the nonattainment area is presumed to be the county.

The highest measured design value for monitors in the vicinity of the Glover facility is also 

included in Table 9 above. The air monitoring data from monitors in the vicinity of the Glover 

facility show attainment with the 2008 NAAQS for 2007-2009. 

Figure 10 depicts the active air monitors, Buick North and South, that currently exceed the 2008 

NAAQS, as well as the new monitors for the mining and milling operations that began operating 

in January 2010. Historically, there were two additional air monitors located to the northwest of 

Buick that also monitored violations of the 2008 NAAQS. These monitoring locations were 

discontinued in 2001. The Buick North and South monitors recorded about the same 

concentrations of lead for the 2007 – 2009 time period, with the highest concentration of 2.46 

ug/m

3

detected in the October – December calendar quarter of 2008 at the Buick South monitor. 

This exceedence set the design value.
25

Figure 10. Iron, Dent, and Reynolds County Air Monitor Locations
26

MDNR used AERMOD to conduct a dispersion model analysis to predict lead concentrations in 

the vicinity of the Buick smelter, mine and mill and for the other mining and milling operations 

in the Viburnum Trend area. The maximum permitted emissions were used to model the Buick 

smelter emissions. Fugitive emissions from haul route traffic and buildings were included in the 

model. In addition, MDNR observed a “stack” test conducted by Doe Run’s contractor at one of 

the mine shaft vents to gather data to represent emissions from the mines for use in the model. 

The Buick/Viburnum Trend modeling results are depicted on Figures 11 and 12 below.

The Buick/Viburnum Trend modeling indicates that predicted violations of the 2008 NAAQS are 

within the property boundaries for the mining and milling operations, with the exception of the 

Buick mine and mill and one receptor north of the Fletcher mine and mill. The model predicts 

2008 NAAQS exceedences between the Buick smelter and the Buick mining and milling 

operations. 

MDNR conducted further analysis of the potential for contribution from these sources of lead 

emissions to one another. The analysis indicates that the Buick smelter, mine and mill (modeled 

together) contributes 2.5% to the predicted concentrations in the vicinity of the other mine and 

milling operations (Brushy Creek, Fletcher, and Sweetwater). The analysis also indicates that 

the other mine and milling operations contribute less than 1% to the predicted concentration for 

the Buick smelter, mine and mill.

EPA also conducted an independent review of the Buick/Viburnum Trend modeling results and 

the review is discussed in the Memorandum dated April 30, 2010, previously referenced. 6

The modeling performed for the Buick/Viburnum used meteorological data obtained from Fort 

Leonard Wood, which is about 35 miles west of the Buick smelter facility. The upper air data 

were obtained from the NWS radiosonde site located near Springfield, Missouri. The modeled 

period extended from August 1, 2005 to December 31, 2007. Fugitive emissions for the mining 

and milling operations represented a large portion of the source characterization.

2. Emissions and Emissions-Related Data

Evidence of lead emissions sources surrounding a violating monitor are an important factor for 

determining whether a nearby area is contributing to a monitored violation. For this factor, EPA 

evaluated county level emission data for lead and population data. 

Emissions data that appear on Figure 8 were derived from the 2002 National Air Toxics 

Assessment, which is the most up-to-date version of the national inventory available to the 

public when these data were compiled for the designations process in 2009. See 

http://www.epa.gov/ttn/atw/natamain/.
27

Figure 11. Iron, Dent & Reynolds Counties Modeling Results – North
28

Figure 12. Iron, Dent & Reynolds Counties Modeling Results – South

2.
29

Table 10 shows total emissions of lead (given in TPY) for violating and potentially contributing 

counties in and around the recommended Iron, Dent and Reynolds Counties nonattainment area

and sources emitting greater than 0.5 ton per year of lead according to NATA , cross-referenced 

with the 2007-2009 state emissions inventory, MoEIS. Based on the 2002 NATA and MoEIS, 

there are no other sources of lead emissions either within or outside Iron, Dent and Reynolds 

Counties that are contributing to the recommended nonattainment area for the 2008 Lead 

NAAQS.

Table 10. Lead Emissions for Iron, Dent and Reynolds Counties

County Facility in State

Recommended 

Nonattainment

Area?

Facility – Total Air 

Emissions (tons per 

year)

Facility Total County Lead 

Emissions

(TPY))

Iron, Dent & 

Reynolds

Yes 12.41 Buick secondary 

Smelter, Mine/Mill 

12.51

Iron No 0.121 Glover former 

primary smelter

12.51

Dent Yes 0.0182 Buick secondary 

Smelter

0.0182

Reynolds No 2.92

Fletcher Mine/Mill 5.42

Reynolds No 1.92 Brushy Creek 

Mine/Mill

5.42

Reynolds No 0.62

Sweetwater 

Mine/Mill

5.42

1

– National Air Toxics Assessment (NATA) 2002

2 

– MoEIS, 2008

3. Population Data

Table 11 shows the 2008 population for Iron, Dent and Reynolds Counties in Missouri, which 

includes the Iron, Dent and Reynolds Counties nonattainment area. These data help assess the 

extent to which the concentration of human activities in the area and concentration of populationoriented commercial development may indicate emissions-based activity contributing to elevated 
30

ambient lead levels. This may include ambient lead contributions from activities that would 

resuspend lead that has been deposited on the ground or on other surfaces, such as fugitive 

emissions from the lead concentrate haul routes and lead ore and zinc and copper concentrate 

handling.

Table 11. Population Data

County State Recommended 

Nonattainment?

2008 

Population

2008

Population 

Density 

(pop/sq mi)

Population 

Change

2000-2008

Population % 

Change 2000-

2008

Iron Co., 

Missouri

Yes, partial 9,918 18 -714 -7

Dent Co., 

Missouri

Yes, partial 15,199 20 265 2

Reynolds Co., 

Missouri

Yes, partial 6,388 8 -329 -5

Source: U.S. Census Bureau estimates for 2008 (http://www.census.gov/popest/datasets.html) 

The areas surrounding the Buick secondary smelter and Viburnum Trend are not densely 

populated and is considered rural. EPA does not believe that the population data provided in 

the analysis of this factor affects the boundary determination.

4. Growth Rates and Patterns 

This factor considers population growth for 2000-2008 in the area considered for the 

nonattainment designation. Table 12 below shows population, and population growth for Iron, 

Dent and Reynolds Counties in Missouri. All population data is from the U.S. Census Bureau 

http://www.census.gov/popest/counties/CO-EST2008-popchg2000_2008.html. 

Population declines were observed for Iron and Reynolds Counties from 2000 – 2008, while 

Dent County grew a modest 2%. As stated above, this area of Missouri is rural and so little 

population growth or decline is typical. EPA has considered the population growth rate for this 

area and does not believe that it affects the boundary determination.

5. Emissions Controls

Under this factor, the existing level of control of emission sources is taken into consideration. 

The emissions data used by EPA in this technical analysis and provided in Table 10 above

represent emissions levels taking into account any control strategies implemented which 

previously brought the western Iron County nonattainment area into attainment in 2000, and as a 

part of the 2004 maintenance plan for the Buick facility. 
31

As discussed above, the Glover facility is no longer permitted for pyro-processing operations; the 

emissions from the facility from 2003 to the present are fugitive emissions from handling lead 

ore and zinc and copper concentrate. 

6. Meteorology

For this factor, EPA considered data from NWS instruments and other meteorological 

monitoring sites in the area. Wind direction data for the area are depicted in Figure 13 below. 

The three-dimensional bar chart above shows the wind frequencies in eight directions for the 

four seasons. The chart frequencies reflect the directions from which the winds come. Based on 

Figure 13, it may be concluded that the wind originates predominately from the WNW in the 

winter months and from the SSW during summer months. These meteorological conditions are 

similar to that found at Herculaneum (Figure 7), with the exception of the influence of the river 

valley observed in the on-site monitors at Herculaneum. As discussed above, meteorological 

data from Fort Leonard Wood which is approximately 35 miles west of Buick smelter facility

were used in the lead concentration modeling analysis. There are lead air monitors located both 

north and south of the Buick smelter facility, and new monitoring locations at Buick, Brushy 

Creek, Fletcher and Sweetwater mine and milling operations to the south of Buick. The 

additional new monitors should provide sufficient information to determine NAAQS compliance 

in areas for which there is little or no historic data. The Iron, Dent and Reynolds Counties 

nonattainment boundary determination is supported by the meteorological data.
32

Figure 13. Buick/Viburnum Trend Meteorological Data

Source: 1960-1992 Solar and Meteorological Surface Observation Network information issued jointly by the U.S. 

Department of Commerce: National Climatic Data Center and the U.S. Department of Energy: National Renewable 

Energy Laboratory

7. Geography/Topography

The geography/topography analysis evaluates the physical features of the land that might have an 

affect on the air shed and, therefore, on the distribution of lead over the proposed Iron, Dent and 

Reynolds Counties nonattainment area.

The Iron, Dent and Reynolds Counties nonattainment area is in a rural portion of southeastern 

Missouri in the Ozarks region. The area is characteristically wooded and has significant 

topographic relief. USGS topographic maps indicate as much as 200 feet of relief in this area. 

Topography most likely influences ambient air transport and weather patterns. Topography and 

regional weather patterns are accounted for in the dispersion modeling conducted by MDNR; 

therefore, this factor played an indirect role in establishing the nonattainment boundary in 

western Iron, Dent and Reynolds Counties. 

The Glover facility in eastern Iron County lies in a valley and is located approximately 40 miles 

to the east of the Buick smelter, mine and mill. Due to the geographic distance of the Glover 

facility from the nonattainment area, and because the Glover facility lies within a valley, EPA

believes that the emissions from lead handling activities at the Glover facility do not contribute 

to the Iron, Dent and Reynolds Counties nonattainment area.
33

8. Jurisdictional boundaries 

Existing jurisdictional boundaries may be helpful in determining a boundary for purposes of 

nonattainment designations, and for purposes of carrying out the governmental responsibilities of 

planning for attainment of the lead NAAQS and implementing control measures. These existing 

boundaries may include an existing nonattainment or maintenance area boundary, a county or 

township boundary, a metropolitan area boundary, an air management district, or an urban 

planning boundary established for coordinating business development or transportation activities.

In the area surrounding the Buick smelter, there is no clear jurisdictional boundary which defines 

the nonattainment boundary. The Buick smelter lies in Iron County; however, the proposed 

nonattainment area extends to a small portion of Dent County to the east and Reynolds County to 

the south. The Buick mine and milling operations extend into Reynolds County, Missouri. The 

air monitoring data from the Buick South monitor and the modeling indicate that it is appropriate 

to include portions of Reynolds County in the lead nonattainment area. The nonattainment area 

therefore must be described officially by township, section and range, consistent with the State’s 

designation recommendation.1 

9. Other Relevant Information

EPA received additional information from the State relevant to establish a nonattainment area 

boundary for portions of Iron, Dent and Reynolds Counties in Missouri. As discussed in Section 

1 above, MDNR submitted the results of a dispersion model analysis in support of its boundary

determination. EPA considered this information and conducted an independent analysis in 

making its boundary determination for the Iron, Dent and Reynolds Counties nonattainment area. 

Summary

EPA is designating portions of Iron, Dent and Reynolds Counties in Missouri which include Doe 

Run’s Buick smelter and Buick mining and milling operation as identified in Figures 8 and 9 as 

the nonattainment area for the 2008 Lead NAAQS. 

Two air quality monitors in Iron County one north and one south of Doe Run’s Buick secondary

smelter facility show violations of the 2008 Lead NAAQS based on 2007 - 2009 air quality data. 

Therefore, a nonattainment designation is required for all or some of Iron County. The relevant 

information, including monitoring and modeling results, supports a partial county designation for 

Iron County and the expansion of the boundary into portions of Dent and Reynolds Counties. 

Based on its consideration of all the relevant, available information, as described above, EPA 

believes that the boundaries described herein encompass the entire area that does not meet (or 

that contributes to ambient air quality in a nearby area that does not meet) the 2008 Pb NAAQS. 

This area will be re-evaluated in the second round of designations, taking into consideration all 

newly available data and information. 
34

Definition of important terms used in this document:

Designated “unclassifiable” – an area where EPA could not determine if there was a violation 

of the 2008 Lead NAAQS because there was incomplete air quality data for a three year period 

either in 2006-2008 or 2007-2009.

Designated “attainment” – an area which EPA has determined that based on the most recent 

three years of certified air quality data from 2006-2008 or 2007-2009 has no violations of the 

2008 Lead NAAQS during 36 consecutive valid three-month rolling site averages; and EPA does 

not believe that the area contributes to a violation of the 2008 Lead NAAQS in a nearby area.

Designated nonattainment area – an area which EPA has determined, based on a State 

recommendation and/or on the technical analysis included in this document, has a violation of 

the 2008 Lead NAAQS for the most recent three consecutive years of quality-assured, certified 

air quality data. Further, a site does not have to monitor for three full calendar years in order to 

have a valid violating design value; a site could monitor just three months and still produce a 

valid (violating) design value.

Prior nonattainment area – an area that is currently designated as nonattainment or 

maintenance for the 1978 Lead Standard (including both current nonattainment areas and 

maintenance areas).

Recommended nonattainment area – an area a State or Tribe has recommended to EPA be 

designated as nonattainment.

Violating monitor – an ambient air monitor whose design value exceeds 0.15 micrograms per 

cubic meter (ug/m3). As described in Appendix R of part 50, a violation can be based on either 

Pb-TSP or Pb-PM10 data and only three months of data are necessary to produce a valid 

violating design value. 

1978 Lead NAAQS – 1.5 μg/m3, National Ambient Air Quality Standard for lead promulgated 

in 1978. Based on Pb-TSP indicator and averaged over a calendar quarter.

2008 Lead NAAQS - 0.15 μg/m3, National Ambient Air Quality Standard for lead promulgated 

in 2008. Based on Pb-TSP indicator and a three-month rolling average. Pb-PM10 data may be 

used in limited instances, including to show nonattainment.