County Affected:

Parts of Pinal County | View on a Map >

Nonattainment Area Designation Date:

Oct. 31, 1990
(55 FR 45799)

Classification Level: 

Moderate

Pollutant of Concern:

PM₁₀ (particulate matter 10 microns or less in diameter; 1987 standards)

Summary: 

The concentration of PM₁₀ in the air in Hayden has recently triggered violations of the 1987 PM10 National Ambient Air Quality Standards (NAAQS). ADEQ is developing a redesignation request so that EPA will reclassify the area to attainment. As part of this request, ADEQ must include an updated emissions inventory, modeling demonstration and a strategy for Exceptional Events. ASARCO is making numerous improvements to the Hayden smelter as part of a $180 million converter retrofit project which will further reduce PM₁₀ concentrations. Some of the controls implemented at the copper smelter include:

• Ventilation hooding over furnaces
• Baghouses for flash furnace and anode furnace
• Paved road cleaning
• Chemical dust suppressants for unpaved roads
• Enclosed and ventilated storage of acid plant scrubber blowdown solids
• Wind fences for byproduct storage​

Sources of Pollutant: 

• Copper smelter
• Open burning and wildfires
• Windblown dust

Unfamiliar with some of the acronyms or technical terms used on this page?

Visit our glossary | View Glossary >