This is a Consent Decree between US EPA and ASARCO (Respondent) for Respondent's alleged violations of the Clean Air Act National Emission Standards for Hazardous Air Pollutants and the Title V Operating Permit Program at its Hayden, Arizona copper smelting facility. Respondent has agreed to pay a civil penalty of $4,500,000 and will implement complying actions valued at nearly $1.6 Million to address alleged violations, as well as perform a Supplemental Environmental Project (SEP) to reduce particulate emissions through the use of a diesel-electric locomotive engine as a primary switch locomotive to move ore at the smelter facility.