Skip to main content
Press Release

U.S. EPA Requires Asarco to Cut Toxic Emissions at 103-Year-Old Arizona Copper Smelter

For Immediate Release
Office of Public Affairs

Today, the Department of Justice and the Environmental Protection Agency (EPA) announced a settlement with ASARCO requiring the company to spend $150 million to install new equipment and pollution control technology to reduce emissions of toxic heavy metals at a large smelter located in Hayden, Arizona.  The company will also fund local environmental projects valued at $8 million, replace a diesel locomotive with a cleaner model for $1 million, and pay a $4.5 million civil penalty.

The federal enforcement action targeted hazardous air pollutants, including lead and arsenic, and particulate matter (PM).  With the controls in place, the hazardous air pollutants should be reduced by at least 8.5 tons per year, and PM emissions are expected to be reduced by 3,500 tons per year. The new equipment and controls will also slash the facility’s sulfur dioxide (SO2) emissions by 19,000 tons per year, a reduction of more than 90 percent, according to EPA estimates.  Currently, the ASARCO smelter is the largest source of SO2 emissions in Arizona.

“This settlement will bring tremendous benefits to public health and the environment in Arizona for generations to come through dramatic cuts to harmful air emissions,” said Assistant Attorney General John C. Cruden for the Justice Department’s Environment and Natural Resources Division.  “The requirements of this consent decree will not only bring ASARCO into compliance with the nation’s clean air law, but will also result in testing for lead contamination in area homes and improvements to nearby roads to further improve air quality.”

“Big enforcement actions like this result in big returns for American communities,” said Assistant Administrator Cynthia Giles for EPA’s Office of Enforcement and Compliance Assurance.  “The upgraded pollution controls and advanced monitoring technologies ASARCO will install are key to a modern compliance program that cuts pollution around industrial plants.”

“The communities living near this century-old smelter will breathe cleaner air as a result of this landmark enforcement action,” said Regional Administrator Jared Blumenfeld for EPA’s Pacific Southwest Region.  “As one of only three major copper smelters in the nation, it is critically important that the facility operate in a way that complies with federal law, minimizes harmful pollutants and safeguards public health and the environment.”

EPA’s investigation found the company violated federal Clean Air Act standards by failing to adequately control emissions of hazardous air pollutants, such as arsenic and lead, from the Hayden smelter.  Under the settlement announced today, ASARCO will install new and upgraded ventilation hoods to capture hot flue gases from its furnaces to better capture the PM, which includes the hazardous air pollutants and SO2.  The company will also replace an aging electrostatic precipitator with a new, cleaner baghouse and inject high performance lime to reduce SO2 emissions.

To reduce wind-blown dust from the facility, which contains varying levels of heavy metals, the company will implement an improved dust control plan, including the use of wind fences, upgraded water sprayers and the installation of concrete pads.  In addition, ASARCO will operate five ambient air monitors in and around the Hayden and Winkelman communities to track levels of pollutants, including arsenic, lead and PM and will make additional improvements to dust controls if levels are high. 

The settlement requires ASARCO to spend $8 million to fund two environmental mitigation projects.  Of this, $6 million will be used on a road paving project in Pinal County that will reduce dust pollution on local dirt roads close to the towns and benefit residents exposed to PM emissions.  In addition, $2 million will be provided to the Gila County Environmental Health Services to conduct lead-based paint testing and abatement in homes, schools and other public buildings in the towns of Hayden and Winkelman.

ASARCO will spend approximately $1 million to replace an existing diesel switch locomotive operated at the facility with a cleaner diesel-electric switch locomotive.  The project will reduce emissions of nitrogen oxides, which are precursors to the formation of PM2.5 and greenhouse gases. 

Long-term inhalation exposure to inorganic arsenic is associated with irritation of the skin and can affect the brain and nervous system. Exposure to lead can cause effects on the blood, as well as the nervous, immune, renal and cardiovascular systems.  Particulate matter, especially inhalable coarse particles (PM10) and fine particles (PM2.5), can cause coughing or difficulty breathing, decreased lung function, aggravated asthma and even premature death in people with heart or lung disease.  SO2 has also been linked to a number of adverse effects on the respiratory system and SO2 is also a precursor to the formation of PM2.5.  Fine particles are also the main cause of reduced visibility (haze) in parts of the United States, including national parks and wilderness areas.  The PM2.5 and SO2 emission reductions achieved through compliance with this settlement will also serve to reduce visibility impairment owing to emissions from the facility.

Built in 1912 and expanded over the years, the ASARCO Hayden site is a copper ore processing, concentrating and smelter facility located adjacent to Hayden and Winkelman.  The ASARCO plant includes a crusher, concentrator, smelter and tailings impoundment areas and produces 300 to 400 million pounds of copper and over half a million tons of sulfuric acid annually.  ASARCO is owned by Grupo México, a Mexican consortium that owns Ferromex, the largest railroad in Mexico and operates mines and smelters, including the one in Hayden, that make it the fourth largest copper producer in the world.  The Hayden facility is one of three copper smelters in the United States, and the only one owned by ASARCO.

The settlement was lodged with the U.S. District Court of Arizona and is subject to a 30-day public comment period and final court approval. The proposed consent decree can be viewed at:

More on the settlement:

Updated April 5, 2024

Press Release Number: 15-1352