i 

Hayden, Arizona 

Redesignation to Nonattainment for the 

2008 Lead National Ambient Air Quality Standard 

Technical Support Document 

April 2014 

US EPA, Region 9 
ii 

List of Figures and Tables 

Figure 1 Violating Monitor and Surrounding Area 

Figure 2 Pb Monitors in Arizona and Associated Design Values 

Figure 3 Pb Sources near the Violating Monitor (2008 NEI) 

Figure 4 Counties and Cities near Hayden, Arizona 

Figure 5 Terrain near Hayden, Arizona 

Figure 6 Tribal Lands and SO2 Nonattainment Area Boundary 

Figure 7 Monthly Pb Concentration Averages – ADEQ Globe Highway Monitor, 2011-

2013 

Figure 8 Map of New Monitoring Network 

Figure 9 Pb Concentrations – ADEQ Globe Highway Monitor and ASARCO Globe 

Highway monitor 

Figure 10 Pb Concentrations – ASARCO Monitors 

Table 1 Air Quality Data – Pb Monitors in Arizona 

Table 2 Air Quality Data – Design Values from Globe Highway Monitor 

Table 3 Arizona Facilities Emitting > 0.10 TPY According to the 2008 NEI and Draft 

2011 NEI 

Table 4 Airports in Arizona Emitting > 0.10 TPY According to the 2008 NEI and Draft 

2011 NEI 

Table 5 Population Data 

Table 6 Historical and Projected Population in Gila and Pinal Counties, and Selected 

Towns near Hayden, Arizona 

Table 7 Data from New Monitoring Network and ADEQ’s Globe Highway Monitor 
iii 

Definitions of Important Terms Used in This Document 

2008 Lead (Pb) NAAQS - The National Ambient Air Quality Standard for lead promulgated in 

2008 is 0.15 micrograms per cubic meter (μg/m3). The standard is based on a Pb-TSP indicator 

and a three-month rolling average. 

Design Value – A site-level metric that is compared to the NAAQS level to determine 

compliance. The design value for the Pb NAAQS is selected in accordance with the procedures 

in 40 CFR part 50, Appendix R from among the valid three-month Pb-TSP and surrogate Pb-TSP 

(Pb-PM10) arithmetic mean (“average”)concentrations for the 38-month period consisting of the 

most recent three-year calendar period plus two previous months (i.e., 36 rolling three-month 

periods consisting of a 3-year calendar period and the two months prior to the beginning of the 3-

year period) using the last month of each three-month period as the period of report. 

Violating monitor – An ambient air monitor whose design value exceeds 0.15 μg/m3. As 

described in Appendix R of 40 CFR part 50, a violation can be based on either Pb-TSP or PbPM10 data and only three months of data are necessary to produce a valid violating design value. 

“Attainment” designation – The designation given to a geographic area within which EPA has 

determined, based on the most recent three years of certified air quality data, no violations of the 

2008 Pb NAAQS occurred during 36 consecutive valid three-month site averages, and that EPA 

has further determined does not contribute to a violation of the 2008 Pb NAAQS in a nearby 

area. 

 “Nonattainment" designation – The designation given to a geographic area that EPA has 

determined, based on a State recommendation and/or on technical analysis, has a violation or has 

contributed to a violation of the 2008 Pb NAAQS during the most recent three consecutive years 

of quality-assured, certified air quality data. 

“Unclassifiable” designation – The initial designation given to the Hayden area because data 

measuring exceedances of the 2008 Pb NAAQS were not quality assured and certified prior to 

the statutory deadline for initial designation. 
iv 

List of Acronyms and Abbreviations Used in this Document 

ADEQ Arizona Department of Environmental Quality 

ADEQ 2009 TSD “Arizona Air Quality Designations Technical Support Document – 

Boundary Recommendation for the 2008 Revision to the National Ambient 

air Quality Standard for Lead,” dated December 9, 2009 

ADEQ 2013 TSD “Relationship Between Ambient Sulfur Dioxide and Lead Concentrations,” 

dated August 23, 2013 

AQS Air Quality System Database 

ASARCO ASARCO-Hayden Copper Smelter 

CAA Clean Air Act 

EPA Environmental Protection Agency 

MAG Maricopa Association of Governments 

MPO Metropolitan Planning Organization 

NAAQS National Ambient Air Quality Standards 

NGS Navajo Generating Station 

NEI National Emissions Inventory 

PAG Pima Association of Governments 

Pb Lead 

SIP State Implementation Plan 

SO2 Sulfur Dioxide 

TSD Technical Support Document 
1 

HAYDEN, ARIZONA 

Redesignation to Nonattainment for the 

2008 Lead National Ambient Air Quality Standards 

BACKGROUND

On October 15, 2008, the Environmental Protection Agency (EPA) revised the primary (healthbased) lead (Pb) national ambient air quality standard (NAAQS), lowering it from the 1.5 

micrograms per cubic meter (mg/m3) level set in 1978 to a level of 0.15 mg/m3(2008 Pb 

NAAQS). The secondary (welfare-based) standard was revised to be identical in all respects to 

the primary standard. See 73 FR 66964, November 12, 2008. An area violates the revised 

standards if any arithmetic 3-month average concentration is greater than 0.15 mg/m3. An area is 

considered to be in compliance with the standards if it has not measured any violations of the 

standards for three consecutive years. 

Under Clean Air Act (CAA) section 107(d)(1)(B), EPA is required to promulgate designations 

for all areas within two years, or, if insufficient information is available, not later than three 

years after promulgation of a new or revised NAAQS. In the initial designation process for the 

2008 Pb NAAQS, areas that violated the standard were designated nonattainment and areas 

whose monitors had measured violations but the data were not certified and quality assured were 

designated unclassifiable. All other areas were designated unclassifiable/attainment.1 

On December 15, 2009, in accordance with the process set out in CAA section 107(d)(1)(A), 

Arizona submitted its recommended designations for the revised Pb standard to the EPA.2 At that 

time, preliminary monitoring data indicated that the Hayden area was violating the new standard. 

The Governor of Arizona recommended that the EPA promulgate an unclassifiable/attainment 

designation for most of the State, but recommended that EPA delay designating the Hayden area 

because the ASARCO-Hayden Copper Smelter (ASARCO), the source of Pb emissions in the 

area, had committed to improve its control of Pb emissions. She further recommended that if the 

Hayden area continued to violate the Pb NAAQS on or after March 2010, it should be designated 

nonattainment. 

On December 17, 2009 the Arizona Department of Environmental Quality (ADEQ) submitted a 

detailed analysis supporting the Governor’s recommendation, including the recommended 

boundaries for the Hayden area (“Arizona Air Quality Designations Technical Support 

Document – Boundary Recommendation for the 2008 Revision to the National Ambient Air 

Quality Standard for Lead,” dated December 9, 2009 and referred to herein as the “ADEQ 2009 

TSD”).3 Subsequently, ADEQ recommended that, if the EPA were to determine that monitored 

concentrations in the Hayden area were exceeding the standard, the EPA should follow the 

 

1 See 75 FR 71033, November 22, 2010 and 76 FR 72097, November 22, 2011. 

2 Letter from Janice K. Brewer, Governor of Arizona, to Laura Yoshii, Acting Regional Administrator, US EPA, 

Region 9, dated December 15, 2009. 

3 Letter (with enclosure) from Benjamin H. Grumbles, Director, Arizona Department of Environmental Quality, to 

Laura Yoshii, Acting Regional Administrator, US EPA Region 9, dated December 17, 2009. 
2 

Governor’s recommendation to promulgate a lead nonattainment area with boundaries identical 

to the Hayden sulfur dioxide (SO2) nonattainment area boundaries with respect to State lands.4,5 

In 2010, in conjunction with the initial designations for the 2008 Pb NAAQS, we undertook a 

technical analysis for the Hayden, Arizona area that identified the monitor that was violating the 

newly revised standard and evaluated nearby areas for contributions to ambient lead 

concentrations in the area.6 EPA evaluated the surrounding area 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 rates and 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 (e.g., modeling where 

done appropriately). 

Based on our consideration of the factors listed above, EPA determined that the boundaries 

recommended by the State in 2009 encompassed the entire area that did not meet (or that 

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

EPA completed its initial designations for the revised Pb NAAQS on November 8, 2011 (76 FR 

72097, November 22, 2011). Most of Arizona was designated unclassifiable/attainment for the 

2008 Pb NAAQS. We designated the Hayden area, with the boundaries Arizona recommended, 

as unclassifiable because data indicating violations of the 2008 Pb NAAQS in the Hayden area 

were still preliminary. In our letter to Governor Brewer notifying her of our action, EPA noted 

that, should we subsequently determine that the lead standards are being violated, we would 

initiate the process to redesignate the Hayden area to nonattainment.7

REDESIGNATION

The CAA grants EPA the authority to change the designation of, or “redesignate,” areas in light 

of changes in circumstances. More specifically, CAA section 107(d)(3) authorizes EPA to revise 

the designation of areas (or portions thereof) on the basis of air quality data, planning and control 

considerations, or any other air-quality-related considerations that EPA deems appropriate. 

Violations of the 2008 Pb NAAQS recorded in 2012 at the ADEQ Globe Highway Monitor 

 

4 Letter from Henry R. Darwin, Director, Arizona Department of Environmental Quality, dated August 15, 2011. 

5 On June 22, 2010, EPA revised the SO2 NAAQS (75 FR 35520) , and on July 25, 2013, the Hayden area, which 

was previously designated nonattainment for the 1971 SO2 NAAQS, was designated nonattainment for the revised 

standard (78 FR 47191, August 5, 2013). The boundaries for both the 2008 Pb unclassifiable area and for the 2010 

SO2 nonattainment area are the same as the boundaries we are proposing for the 2008 Pb NAAQS nonattainment 

area. 

6

See the draft technical support document entitled “ARIZONA, Area Designations for the 2008 Lead National 

Ambient Air Quality Standards.”

7 Letter from Lisa P. Jackson, Administrator, US EPA to Janice K. Brewer, Governor of Arizona, dated November 

8, 2011. 
3 

located near Hayden and Winkelman, Arizona, despite efforts to address Pb emissions at the 

ASARCO facility, led EPA to conclude that the SIP planning and control requirements that are 

triggered by redesignation of an area to nonattainment for the Pb NAAQS would be the most 

appropriate means to ensure that this air quality problem is remedied. 

 

On June 12, 2013, EPA notified the Governor of Arizona that available Pb monitoring data 

indicated that the designation for the Hayden area should be changed from unclassifiable to 

nonattainment.8 Governor Brewer responded on September 25, 2013 with a recommendation that 

the Hayden area not be designated nonattainment “because there have been no lead standard 

violations since June 2012, when the ASARCO Hayden Copper Smelter completed the addition 

of controls [i.e., the installation of baghouses on the anode furnace] to reduce lead emissions.”9

The Governor acknowledged that if additional violations of the 2008 Pb NAAQS occur, a 

designation to nonattainment for the Pb standard would be appropriate and recommended that in 

such case, the lead nonattainment area boundaries be identical to the Hayden SO2 nonattainment 

area boundaries, as recommended in her December 15, 2009 letter. 

On October 4, 2013, ADEQ submitted a technical support document dated August 23, 2013 

entitled “Relationship Between Ambient Sulfur Dioxide and Lead Concentrations”10 in support 

of the Governor’s recommendation (ADEQ 2013 TSD). The ADEQ 2013 TSD examines the 

relationship between ambient concentrations of SO2 and Pb over time, and points to an “abrupt 

change” in the ratio of SO2 to Pb concentrations that occurred around July 2012 as evidence that 

the Pb emissions controls installed at that time have reduced the ambient concentrations of Pb. 

ADEQ concludes that, “[w]hile it is believed that the installed control devices were effective in 

reducing the ambient Pb concentrations in Hayden, AZ, additional data would be needed to 

verify that the Globe Highway Pb monitor continues to attain the Pb NAAQS.” 

In order to show attainment of the Pb NAAQS, an area must have three years of valid air quality 

data without any violations of the 2008 Pb NAAQS, and the area cannot contribute to a 

violation. As shown below, 2012 monitoring data collected at the Globe monitor near the 

ASARCO facility show three exceedances of the 2008 Pb NAAQS. See “Air Quality Data” 

section, below. Further, additional monitoring data collected at sites that began operation in 2013 

indicate that the area continues to violate the standard. See “Additional Relevant Information” 

section, below. In addition to evaluating monitoring data, we have reviewed and, where 

appropriate, updated our 2010 analysis of relevant factors, including emissions-related data, 

weather and transport patterns, topography, and jurisdiction. Based on our technical analysis and 

currently available information, which is described in greater detail below, EPA is proposing to 

redesignate the Hayden area to nonattainment for the 2008 Pb NAAQS, and concurs with the 

State’s recommendation that the area’s existing boundary remain unchanged. 

 

 

8 Letter from Jared Blumenfeld, Regional Administrator, US EPA Region 9 to Janice K. Brewer, Governor of 

Arizona, dated June 12, 2013. 

9 Letter from Janice K. Brewer, Governor of Arizona, to Jared Blumenfeld, Regional Administrator, US EPA 

Region 9, dated September 25, 2013. 

10 Letter (with enclosure) from Eric C. Massey, Director, Air Quality, ADEQ, to Jared Blumenfeld, Regional 

Administrator, US EPA Region 9, dated October 4, 2013. 
4 

The map below identifies the portions of Pinal and Gila counties in Arizona that EPA intends to 

redesignate “nonattainment” for the 2008 Pb NAAQS. The boundaries for this area are identical 

to those for the area currently designated unclassifiable for the 2008 Pb NAAQS and are 

consistent with the Governor’s boundary recommendation. 

Figure 1. Violating Monitor and Surrounding Area 

 

 
5 

AIR QUALITY DATA 

This factor considers the Pb design values (in μg/m3) for air quality monitors in the Hayden area 

and the surrounding area based on certified 2010-2012 data.11 A monitor’s design value 

indicates whether that monitor attains a specified air quality standard. The 2008 Pb NAAQS are 

met at a monitoring site when the identified design value is valid and is less than or equal to 0.15 

μg/m3. A design value is only valid if minimum data completeness criteria are met. A Pb design 

value that meets the NAAQS is generally considered valid if it encompasses 36 consecutive valid 

3-month site averages (specifically for a 3-year calendar period and the two previous months). 

For this purpose, a 3-month site mean is valid if valid data were obtained for at least 75 percent 

of the scheduled monitoring days in the 3-month period. A Pb design value is violating the 

NAAQS if at least one 3-month mean meets the same 75 percent requirement and the level is 

above the NAAQS. That is, 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. 

Pb monitors that collected data in Arizona for all or part of 2010 through 2012 are listed in Table 

1. Of the five monitors that collected data during this time, four have design values well below 

the NAAQS. These include ADEQ’s FMMI Golf Course monitor located near the 

Freeport McMoRan (FMMI) copper mining and smelting facility in Miami, the Deer Valley site 

near the Deer Valley Airport in Phoenix, the James L. Guyton (JLG) Supersite in Phoenix and 

the Children’s Park site in Tucson. Both the JLG Supersite and the Children’s Park site are 

NCore sites, established to collect multipollutant information at sites representative of general 

population exposure. The remaining site, Globe Highway, has a design value above the Pb 

NAAQS (i.e., is violating the Pb NAAQS). 

Table 1. Air Quality Data - Pb Monitors in Arizona 

County State 

Recommended 

Nonattainment? 

Monitor Name Monitor Air 

Quality System ID 

Monitor Location Lead Design Value, 

2010-2012 (μg/m3) 

Gila 

County 

Globe Highway 04-007-1002 SR 77, Winkelman 0.20 

FMMI Golf Course 04-007-8000 SR 188 and US 60, 

Miami 0.041

Maricopa 

County 

Deer Valley 04-013-4018 1030 W. Deer Valley 

Road, Phoenix 0.041

 

JLG Supersite 04-013-9997 4530 N. 17th Ave, 

Phoenix 

0.011,2 

Pima 

County 

Children's Park 04-019-1028 400 W. River Road, 

Tucson 

0.001 

1 Incomplete design value for showing attainment of the standard. 

2 Data collected using a Pb-PM10 monitor. 

 

11As detailed in 40 CFR part 50 Appendix R, all FRM/FEM Pb-TSP and Pb-PM10 data collected in accordance with the 

requirements of 40 CFR part 58, including Appendix A (quality assurance), Appendix C (federal reference methods/federal 

equivalent methods (FRM/FEM)), and Appendix E (siting criteria), are comparable against the Pb NAAQS. 40 CFR part 50, 

Appendix R contains the requirement for data used for comparison with the Pb NAAQS.
6 

ADEQ’s Globe Highway monitor (Air Quality System (AQS) ID 04-007-1002) is located east of 

the ASARCO Hayden copper smelter. ADEQ began operating the Globe Highway monitor at the 

beginning of 2011, making March 2011 the first complete three-month design value for the site. 

All available three-month design values from 2010 through 2012 for the Globe Highway monitor 

are listed in Table 2. In 2011, the design values ending in April 2011, May 2011, June 2011, and 

July 2011 were above the NAAQS. In 2012, the design values ending in April 2012, May 2012, 

and June 2012 were above the NAAQS. ADEQ’s quality assurance project plan for Pb was not 

officially approved by EPA until October 24, 2011, and an expanded version was approved 

January 22, 2013. EPA is thus using the highest design value collected after the quality assurance 

project plan was approved as the highest violating design value, which is 0.20 μg/m3, the threemonth rolling average from both April 2012 and June 2012.12 This is the design value listed for 

Globe Highway in Table 1. At ADEQ’s other Pb monitoring site, FMMI Golf Course, the 

highest design value for the site after the quality assurance plan was approved is 0.04 μg/m3. 

Table 2. Air Quality Data - Design Values from Globe Highway Monitor (AQS ID 04-007-1002) 

Design Values (μg/m3) 

2011 2012 

November-December-January - 0.07 

December-January-February - 0.14 

January-February-March 0.11 0.15 

February-March-April 0.18 0.20 

March-April-May 0.21 0.16 

April-May-June 0.27 0.20 

May-June-July 0.23 0.15 

June-July-August 0.14 0.14 

July-August-September 0.07 0.12 

August-September-October 0.08 0.11 

September-October-November 0.08 0.09 

October-November-December 0.09 0.06 

As shown in Figure 2, the San Carlos Apache tribal lands lie to the east of the recommended 

nonattainment area. There are no Pb ambient air monitors operating within the tribal lands, nor 

do the tribal lands have any sources emitting 0.1 tons per year of Pb or more (see Emissions and 

Emissions-Related Data section below). 

 

12 Preliminary air quality data collected in 2013 are discussed below in the section entitled “Other Relevant 

Information.” 
7 

Figure 2. Pb Monitors in Arizona and Associated Design Values 

The Globe Highway monitor, sited in Gila County and close to the border of Pinal County, is in 

violation of the 2008 Pb NAAQS. Therefore some portion of Gila County and possibly 

additional areas in surrounding counties must be designated nonattainment. We evaluate nearby 

counties because for each monitor or group of monitors that exceed a standard, nonattainment 

boundaries must cover a large enough area to include not only the area judged to be violating the 

standard but also the source areas that are determined to be contributing to the violations. Each 

area has been evaluated based on the weight of evidence of the factors and other relevant 

information described in this technical support document. 
8 

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 emissions data for lead, population data, and emissions controls. 

Emissions

Emissions data provided in Table 3 were derived from the 2008 National Emissions Inventory, 

version 3 (NEIv3), which is the most up-to-date version of the national inventory. See 

http://www.epa.gov/ttn/chief/net/2008inventory.html . Tables 3 and 4 also include draft data 

from the 2011 NEI. These data have not yet been finalized and are subject to change. To 

evaluate the potential impact of emissions at and near these facilities, EPA recommends that 

States use the 2008 NEI until a newer version of the NEI is finalized. This TSD therefore is 

primarily based on information provided in the finalized 2008 NEI. 

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

consumed. The Arizona airports that emit over 0.10 tons per year (tpy) of Pb according to the 

2008 NEI and the draft 2011 NEI are listed in Table 4. 

Table 3. Arizona Facilities Emitting > 0.10 TPY Pb According to the 2008 NEI 

and Draft 2011 NEI* 

County 

Facility in State 

Recommended 

Nonattainment 

Area? Facility Address City 

Facility Total Air 

Releases (tpy) 

2008 NEI 

draft 

2011 

NEI* 

Gila No 

Freeport Mcmoran Miami 

Smelter 5701 New Street Claypool 8.80 4.87 

Gila Yes Asarco LLC - Hayden Smelter 640 Asarco Ave Hayden 4.82 3.88 

Pinal No Asarco Ray Complex 

8 Mi N. of Kearny 

on Hwy 177 Kearny < 0.10 0.25 

Apache No 

SRP - Coronado Generating 

Station 

6Mi/Ne St JohnsHwy191/B1018 St Johns 0.23 0.21 

Maricopa No CMC Steel Fabricators 

11444 E. German N. 

Rd Mesa < 0.10 0.13 

Greenlee No Freeport-McMoran Morenci Inc. 4521 US Hwy 191 Morenci 0.44 0.00 

Coconino No NGS – Navajo Generating Station 

6000 Hwy 98, Page, 

AZ 86040 Page 0.22 0.22 

*Draft NEI is subject to change. 

 

 

 
9 

Table 4. Airports in Arizona Emitting > 0.10 TPY Pb According to the 2008 NEI and Draft 2011 

NEI* 

County 

Airport in State 

Recommended 

Nonattainment 

Area? Facility Type City 

Facility Total Air 

Releases (tpy) 

2008 NEI 

draft 

2011 

NEI* 

Gila No Payson Airport Payson 0.11 0.11 

Pinal No Casa Grande Muni Airport Casa Grande 0.23 0.33 

Cochise No Cochise College Airport Douglas 0.13 0.13 

Cochise No Sierra Vista Muni-Libby Airport Sierra Vista 0.1 0.09 

Maricopa No Phoenix Deer Valley Airport Phoenix 1.32 1.16 

Maricopa No Falcon Field Airport Mesa 1.21 0.77 

Maricopa No Chandler Municipal Airport Chandler 0.92 0.58 

Maricopa No Phoenix-Mesa Gateway Airport Phoenix 0.66 0.41 

Maricopa No Phoenix Goodyear Airport Goodyear 0.6 0.50 

Maricopa No Scottsdale Airport Airport Scottsdale 0.48 0.32 

Maricopa No Glendale Municipal Airport Glendale 0.39 0.24 

Maricopa No Pleasant Valley Airport Peoria 0.21 0.21 

Maricopa No Phoenix Sky Harbor Intl Airport Phoenix 0.13 0.11 

Maricopa No Wickenburg Municipal Airport Wickenburg 0.11 0.14 

Maricopa No Stellar Airpark Airport Chandler 0.11 0.11 

Maricopa No Buckeye Municipal Airport Buckeye < 0.10 0.15 

Mohave No Kingman Airport Kingman 0.14 0.13 

Mohave No Lake Havasu City Airport 

Lake Havasu 

City 0.12 0.09 

Mohave No Grand Canyon West Airport Airport Peach Springs < 0.10 0.11 

Pima No Ryan Field Airport Tucson 0.71 0.31 

Pima No Tucson Intl Airport Tucson 0.37 0.21 

Pima No Marana Northwest Region Airport Marana 0.24 0.29 

Yavapai No Ernest A. Love Field Airport Prescott 0.9 0.89 

Yavapai No Sedona Airport Sedona < 0.10 0.10 

Yuma No Yuma M. C. A. S. Airport Yuma M.C.A.S. 0.14 0.10 

*Draft NEI is subject to change. 

Figure 3 shows the location of airports and point sources in the area near the violating monitor. 

Because of the significant distance, and in most cases, the relatively low levels of emissions, we 

do not believe these sources (other than ASARCO) are causing or contributing to Pb violations 

in the Hayden area. 

There are no known Pb sources emitting 0.1 tons per year of Pb or greater in the San Carlos 

Apache tribal lands. Without any sources emitting over 0.1 tons per year of Pb, it is unlikely the 
10 

San Carlos Apache tribal lands are causing or contributing to violations at the ADEQ Globe 

Highway monitor. 

Figure 3. Pb Sources near the Violating Monitor (2008 NEI)
11 

Population Data, Growth Rates and Patterns 

As noted in EPA’s final Pb designations, EPA generally has found that population density and 

growth are not significant factors in determining the boundaries of Pb nonattainment areas.13

Under some circumstances, however, these factors could help assess the extent to which the 

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

commercial development might indicate emissions-based activity contributing to elevated 

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

disturb lead that has been deposited on the ground or on other surfaces. Re-entrainment of 

historically deposited lead is not reflected in the emissions inventory. Table 5 shows the 2012 

population and population density for counties in the area, and the population change since 2000. 

Table 6 provides projected population growth for towns within or nearby the proposed Hayden 

nonattainment area. 

Table 5. Population Data 

County State 

Recommended 

Nonattainment? 

2000 

Population 

2012 

Population 

2012 

Population 

Density 

(pop/sq mi) 

Population 

Change 

2000-2012 

Population 

% Change 

2000-2012 

Gila Partial 51,335 53,144 11.2 1,809 3.5 

Graham No 33,489 37,416 8.1 3,927 11.7 

Maricopa No 3,072,149 3,942,169 428.5 870,020 28.3 

Pinal Partial 179,727 387,365 72.2 207,638 115.5 

Source: U.S. Census Bureau 

While data contained in Table 5 indicates considerable growth in Pinal County from 2000-2012, 

this growth occurred primarily south and west of the Hayden area. In contrast, the population of 

towns in the Hayden area has declined slightly since 2000 and these towns are projected to have 

little to no growth over the coming years. See Table 6. The ADEQ 2009 TSD shows the Hayden 

area’s population is projected to remain between 0-50 people per square mile through 2030.14

The locations of nearby towns are shown in Figure 4. 

Table 6. Historical and Projected Population for Gila and Pinal Counties, and Selected Towns near Hayden, 

Arizona

2000 2012 2015 2030 

Pinal County 179,727 387,365 414,999 681,578 

Gila County 51,335 53,144 54,149 57,460 

Globe 7,486 7,457 7,544 7,977 

Miami 1,936 1,800 1,837 1,837 

Kearny 2,449 2,007 2,000 2,132 

Winkelman 443 348 353 355 

Hayden 892 652 662 663 

Sources: 2000 and 2012 data: U.S. Census Bureau; 2015 and 2030 projections: Arizona Department of 

Administration, Office of Employment and Population 

 

13 See 76 FR 72097 at 72102. 

14 ADEQ 2009 TSD, pp 8-12. 
12 

Figure 4. Counties and Cities near Hayden, Arizona 

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

the boundary recommendation. 

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 3 and 4 

represent emissions levels taking into account (where applicable) any control strategies 

implemented prior to the relevant data collection. The ADEQ 2009 TSD includes a list of the 

control measures and technologies implemented at the ASARCO facility as of that time.15 Any 

effect on Pb emissions resulting from the installation of baghouses on the anode furnaces in 2012 

is not reflected in the 2008 or the draft 2011 inventories. Despite the addition of controls, data 

 

15 See Appendix D (“Control Measures and Technologies Implemented at the ASARCO Ray Complex and Hayden 

Smelter and Concentrator) of the ADEQ 2009 TSD. 
13 

from 2013 indicate the area continues to violate the Pb NAAQS. See “Other Relevant 

Information” section below. 

METEOROLOGY (weather and transport patterns) 

Due to the constraints imposed by the complex terrain in the Hayden area (see 

Geography/Topography factor), the extent of the area exceeding the Pb standard is confined to a 

relatively small area around the main source of Pb emissions, the ASARCO Hayden smelter. For 

the same reason, locations outside the particular valleys intersecting at Hayden do not contribute 

to NAAQS exceedances there. Therefore, the meteorology factor did not play a significant role 

in determining a boundary for the nonattainment area. 

Meteorological data is available from the very nearby Winkelman 6 S station, part of the 

National Weather Service Cooperative Observer Program. There is typically only 14 inches of 

rain each year, with nearly half occurring July through September, coinciding with the Arizona 

"monsoon" season. There is less than an inch of snow each year. Daily temperature highs range 

from 64 to 91°F depending on season, and lows range from 31 to 69°F. 

Varied elevations in and around Hayden cause complex local wind flow. Within and adjacent to 

the Gila River and San Pedro River valleys, drainage winds tend to dominate at night under 

stable conditions, toward the west on the south and west side of ASARCO, and toward the south 

on the east side of the facility. These conditions cause air pooling in low-lying areas at night, 

causing pollutants within the air to settle in these areas. During the day under convective 

conditions, good vertical mixing may occur. The vertical mixing also causes the flow to be 

coupled with winds aloft, which generally flow toward the east. 

The ADEQ 2009 TSD further describes wintertime conditions. 

During the wintertime, relatively strong inversions (where cold air becomes trapped at the 

surface by warmer air aloft) create extremely stable atmospheric conditions. Depending on 

the strength of the inversion and amount of daytime surface heating, the inversion may 

break by the early afternoon, permitting the air to mix vertically. Sometimes, however, the 

inversion may not break at all. Under these conditions, vertical and horizontal movement 

of the air is very limited, causing pollutants in the air to accumulate up to several days with 

little dispersion.16

As described in the Geography and Topography section below, Hayden's complex terrain limits 

the extent of the area exceeding or contributing to the violation. 

GEOGRAPHY/TOPOGRAPHY (mountain ranges or other air basin boundaries) 

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 Pb over Hayden, Arizona. As shown 

in Figure 5, the ASARCO Hayden smelter is located in very complex terrain, with the Gila River 

 

16 ADEQ 2009 TSD, p 21. 
14 

making a winding semi-circle south of the facility, and intersected by the San Pedro River valley 

from the south. The facility itself is elevated relative to the valleys; there is a 200 foot hill just 

south of the facility, and mountains rising toward the north/northeast. The ADEQ 2009 TSD 

contains the following terrain description: 

Hayden lies in the Gila River Valley, approximately 2,044 feet above sea level. The town sits 

at the base of the Dripping Springs Mountains which rise to a height of approximately 5,096 

feet. The Mescal and Pinal Mountain ranges rise to the east beyond the Dripping Springs 

range to approximately 7,848 feet in elevation at the highest point. To the west of Hayden, 

the Tortilla Mountains rise to a height of 4,273 feet. The complex terrain forms natural 

boundaries that isolate the Hayden area from most of Gila and Pinal Counties.17

In all directions there is a mountain side, limiting the extent of the area exceeding the Pb 

standard to a relatively small area around ASARCO, the main source of Pb emissions. For the 

same reason, locations outside the particular valleys intersecting at Hayden do not contribute to 

NAAQS exceedances there. This supports a relatively small nonattainment area, comprising the 

nearby valleys and mountains, and including a buffer zone. 

Figure 5. Terrain near Hayden, Arizona 

 

17 ADEQ 2009 TSD, p 21. 
15 

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 Pb 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 evaluating the jurisdictional factor, EPA considered the planning and organizational structure 

of Pinal County, Gila County, and the State of Arizona, as well as existing nonattainment 

boundaries, to ensure that the implementation of controls within the prospective nonattainment 

area can be carried out in a cohesive manner. See Figure 4 for county boundaries. 

ADEQ has overall jurisdiction over environmental programs in the state of Arizona, as well as 

jurisdiction over certain source types, including smelters, refineries, and coal-fired power plants, 

and retains authority for regulating emissions from agricultural operations. Three Arizona 

counties, Maricopa, Pima, and Pinal, have their own air pollution control programs and operate 

pursuant to agreements with ADEQ. The lead air quality planning agencies responsible for state 

implementation plans (SIPs) for Maricopa County and Pima County are the metropolitan 

planning organizations (MPOs) – the Maricopa Association of Governments (MAG) and the 

Pima Association of Governments (PAG), respectively. The MPO for a portion of Pinal County, 

the Sun Corridor MPO, has not been certified by the Governor of Arizona as the air quality 

planning agency for SIP purposes in Pinal County. There is no MPO in Gila County. While the 

Pinal County Air Quality Control District can issue permits, write, and enforce rules, it does not 

have the authority to develop SIPs. ADEQ is therefore responsible for developing SIPs for these 

counties. 

As shown in Figure 6, the San Carlos Apache tribal lands lie to the east of the recommended 

nonattainment area in both Pinal County and Gila County. Neither ADEQ nor the counties have 

jurisdiction over tribal lands. 

The intended Pb nonattainment area boundary is identical to that of the existing Hayden Pb 

unclassifiable area. Arizona has recommended excluding Indian Country from the area, as the 

State has no jurisdiction over Indian lands.18 As noted in the “Other Relevant Information” 

section below, the Winkleman monitor, located just east of Hayden and west of the San Carlos 

Apache tribal lands, has a preliminary design value of 0.02 μg/m3, well below the standard. 

There are no known Pb sources emitting 0.1 tons per year of Pb or greater in the San Carlos 

Apache tribal lands. Given the air quality data, lack of sources, and the State's lack of 

jurisdiction, EPA supports excluding the San Carlos Apache tribal lands from the recommended 

Hayden Pb nonattainment area. 

 

18 ADEQ 2009 TSD, section 4.6, p 21. 
16 

Figure 6. Tribal Lands and SO2 Nonattainment Area Boundary 
17 

OTHER RELEVANT INFORMATION

Data from calendar year 2013 have not yet been certified as being completely submitted and 

accurate. This certification is due by May 1, 2014 for data collected in calendar year 2013, 

pursuant to 40 CFR 58.15. EPA therefore presents data from 2013 as supplemental information 

for this action. 

As of March 31, 2014, data through December 31, 2013 from ADEQ’s Globe Highway monitor 

(04-007-1002) are available in EPA’s AQS database. Figure 7 below shows monthly averages 

from the ADEQ Globe Highway site, 2011 - 2013. ADEQ’s October 4, 2013 letter states that 

ASARCO installed controls in June 2012.19 Data collected in 2011, 2012, and 2013 show lower 

monthly averages in the second half of the years. Two monthly averages from 2013 were above 

the 0.15 μg/m3level of the Pb NAAQS. The ADEQ Globe Highway monitor did not record any 

three-month rolling averages that violated the Pb NAAQS in 2013. 

Figure 7. Monthly Pb Concentration Averages – ADEQ Globe Highway Monitor, 2011-2013 

In July 2013, ASARCO installed and began collecting monitoring data from a new network of 

ambient air monitors around the facility. Five new monitors were installed (see Figure 8). Data 

from these monitors have not been fully validated and are presented here as supplementary 

information. The monitors were sited in accordance with 40 CFR 58. 

 

19 Letter from Eric C. Massey, Director, Air Quality, ADEQ, to Jared Blumefeld, Regional Administrator, US EPA 

Region 9, dated October 4, 2013. 

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec

Concentration (ug/m3)

Monthly Averages: 

ADEQ Globe Hwy Data (04-007-1002) for January 2011 - June 2013.

ADEQ - 2011 ADEQ - 2012 ADEQ - 2013
18 

Figure 8. Map of New Monitoring Network

The new monitoring network includes a monitor (Globe Highway-ASARCO) located 14 meters 

southwest of ADEQ’s Globe Highway monitor. Preliminary, uncertified data from both Globe 

Highway monitors are available for September-November 2013. The Globe Highway-ASARCO 

monitor measured approximately 0.017 μg/m3 higher on average than ADEQ’s Globe Highway 

monitor. Given the complex terrain in the ravine where these monitors are located, winds may be 

impacting these monitors differently. While the two monitors measured slightly different values, 

they trend well with one another. (See Figure 9.) 

In reviewing the analytical procedures employed by the laboratory performing analysis on the 

ADEQ filters (Pima County Regional Wastewater Reclamation Department Compliance & 

Regulatory Affairs Office (CRAO) Laboratory) and the laboratory performing analysis on the 

ASARCO filters (Inter-Mountain Laboratories (IML)), EPA found that the sample preparation 

step differed between the two laboratories. While both laboratories followed approved Federal 

Equivalent Methods (FEMs), EPA recommended that CRAO review its sample preparation 

method to determine if additional best practices may be appropriate. Initial analyses by CRAO 
19 

indicate employing additional best practices may yield results of approximately 11% more lead 

per sample. The laboratory analytical procedures were otherwise found to be comparable.20 

Figure 9. Pb Concentrations – ADEQ Globe Highway Monitor and ASARCO Globe Highway Monitor 

Of the five new ASARCO monitors, the three monitors sited to the west and to the southwest of 

the facility show higher averages than the Globe Highway-ASARCO monitor. In September 

2013, the monthly averages for the Post Office, Hillcrest Avenue, and Parking Lot monitors were 

1.5 to 4.5 times higher than the monthly average for the Globe Highway-ASARCO monitor. The 

two complete three-month averages measured to date at the Parking Lot monitor are well over 

the standard, at 0.40 μg/m3for August-October 2013, and 0.65μg/m3(more than four times over 

the standard) for September-November 2013. The three-month average from SeptemberNovember 2013 at the Hillcrest Avenue monitor was also over the standard, at 0.19 μg/m3

. 

These elevated levels indicate that while the ADEQ Globe Highway monitor may be recording 

levels below the standard, other locations around the smelter that the public has access to may be 

experiencing higher concentrations (see Table 7). 

 

20 Memorandum “Review of Laboratory Procedures to Address Accuracy Concerns for Inter-Laboratory Bias for the 

Asarco Superfund Site,” from Joe Eidelberg and Mathew Plate, to Gwen Yoshimura and John Hillenbrand, EPA 

Region 9. March 31, 2014. 

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0.140

Concentration (ug/

m3)

Date (mm/dd/yyyy)

Daily Pb-TSP Concentrations, 

Globe Highway-ADEQ and Globe Highway-ASARCO

Globe Hwy - ASARCO Globe Hwy - ADEQ
20 

Table 7. Data from New Monitoring Network and ADEQ’s Globe Highway Monitor. Pb Concentrations (μg/m3). 

In January 2014, EPA conducted a Technical System Audit (TSA) of the ASARCO ambient air 

monitoring program. EPA found that the ambient air monitoring network was well run. EPA also 

identified areas where the program should be strengthened.21 As previously noted, the ASARCO 

 

21 Final Report, April 2014. Technical System Audit, ASARCO Hayden Plant Site, Ambient Air Monitoring 

Program, January 22-January 28, 2014. 
21 

data remain preliminary and have not gone through a full data validation process. Given the 

technical system audit findings and that these processes have not been completed, EPA has 

evaluated the use of this set of secondary data by considering trends, gradients, and the 

magnitude of measured concentrations relative to the standard. 

As shown in Figure 9, the Globe Highway-ASARCO monitor trends well with the Globe 

Highway-ADEQ monitor. Given that lead is heavy and expected to fall out of the air quickly, 

lead concentrations would generally be highest next to the facility and near specific facility 

operations that produce point or area/fugitive source emissions. An exception to this would be if 

the main emission point was through a tall stack at high temperatures, resulting in the air mass 

remaining buoyant for a time before falling out to breathing-level heights. The data in Table 7 

show that the monitors sited closest to the facility have the highest concentrations and that 

concentrations are lower at monitors sited farther from the facility. This indicates that fugitives 

or other non-stack emissions may have more significant air quality impacts on the neighborhood 

surrounding the facility during these months than stack emissions. The Hillcrest Avenue and 

Parking Lot monitors, both to the southwest of the facility and close to materials handling 

activities, also trend well with one another (see Figure 10). 

Figure 10. Pb Concentrations – ASARCO Monitors 

Given the strong trends and gradient apparent from the available preliminary data, and that the 

parking lot monitor is over four times the standard, the secondary data are adequate to indicate 

concentrations near the facility remain a concern. 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

Concentration (ug/

m3)

Date (mm/dd/yyyy)

ASARCO Pb-TSP Monitors - Daily Pb Values

Hillcrest Ave. Parking Lot Winkelman HS

Globe Highway Post Office Post Office collo
22 

EPA and ADEQ have discussed the challenge of siting a single, source-specific monitor to 

capture the maximum ambient concentration of Pb given the complex meteorology and 

topography found in the Hayden area. While the Globe Highway site was chosen to capture the 

maximum concentration using the information available at the time,22 this recent information 

provided by a more extensive monitoring network indicates that it is appropriate to consider 

whether additional monitoring by ADEQ may be appropriate, as higher concentrations may exist 

elsewhere in the Hayden area. 

CONCLUSION

Preliminary data suggest that the installation of pollution control equipment on the anode 

furnaces at the ASARCO facility might have resulted in a reduction of ambient Pb 

concentrations, as measured at the Globe Highway monitor; however, based on the form of the 

Pb standard (i.e., three consecutive years without a violation are required before an area can be 

considered to be attaining the standard), the monitor continues to have a design value that 

violates the standard. Further, the more extensive monitoring network recently installed provides 

evidence that the Globe Highway monitor is not capturing maximum ambient concentrations of 

Pb and that the area continues to violate the Pb standards. Therefore, based on our analysis of the 

relevant, available information and after considering the factors described above, EPA concludes 

it is appropriate to redesignate the Hayden area to nonattainment for the 2008 Pb NAAQS. 

We have revisited our 2010 analysis of the boundaries for the Hayden area, and conclude the 

boundaries remain appropriate. Therefore, consistent with Arizona’s recommendation, the 

proposed nonattainment area boundary for the Hayden area is unchanged and includes: 

T4S, R14E; 

T4S, R15E; 

T4S, R16 E (except that portion in the San Carlos Indian Reservation) 

T5S, R14E; 

T5S, R15E; 

T5S, R16 E (except that portion in the San Carlos Indian Reservation) 

T6S, R14E; 

T6S, R15E; 

T6S, R16 E (except that portion in the San Carlos Indian Reservation) 

If finalized, the effect of this proposed action would be to redesignate the Hayden area from 

unclassifiable to nonattainment for the Pb NAAQS and thereby to impose certain planning 

requirements on the State of Arizona to reduce Pb concentrations within this area. Those 

requirements, include, but are not limited to, the requirement to submit, within 18 months of 

redesignation, a revision to the Arizona state implementation plan that provides for attainment of 

the Pb NAAQS.23 The implementation plan for the area must contain, among other things, the 

following: 

 

22 Quality Assurance Program Plan for the Lead (Pb) Ambient Air Monitoring Network, Attachment A. Arizona 

Department of Environmental Quality, October 2011. 

23 EPA has issued guidance on the statutory requirements applicable to Pb nonattainment areas. See 57 FR 13498 

(April 16, 1992); 58 FR 67752 (December 22, 1993); 73 FR 66964 (November 12, 2008); and the memorandum 
23 

· provisions to assure that reasonably available control measures (including reasonably 

available control technology) are implemented as expeditiously as practicable; 

· a permit program meeting the requirements of section 173 of the Act governing the 

construction and operation of new and modified major stationary sources of Pb; 

· provisions under 172(c)(2) ensuring reasonable further progress, specifically, adherence 

to an ambitious compliance schedule that is expected to periodically yield significant 

emission reductions, and as appropriate, linear progress toward timely attainment; 

· a demonstration (including air quality modeling) that the plan will provide for attainment 

of the Pb NAAQS as expeditiously as practicable, but no later than five years after the 

area’s designation as nonattainment; and 

· contingency measures pursuant to section 172(c)(9) of the Act, that take effect without 

further action by the State or EPA, upon a determination by EPA that the area has failed 

to make reasonable further progress. 

The new Pb nonattainment area will be subject to EPA’s general conformity regulations (40 CFR 

part 93, subpart B) upon the effective date of redesignation. See section 176(c) of the Act. 

 

signed by Scott Mathias, Interim Director, Air Quality Policy Division, Office of Air Quality Planning and 

Standards, US EPA, entitled “2008 Lead (Pb) National Ambient Air Quality Standards (NAAQS) Implementation 

Questions and Answers” dated July 8, 2011.