Summary
EPA is issuing a notice of proposed action under the Clean Water Act to reissue a National Pollutant Discharge Elimination System (NPDES) permit AZ0024635 to:
ASARCO LLC
4201 West Pima Mine Road
Sahuarita, AZ 85629
EPA is soliciting comments on the reissuance of the NPDES permit for the ASARCO Mission Mine Complex for discharge from a stormwater storage reservoir called Tailings Storage Facility No. 3 located on the Mission North Complex which is on Tribal land of the San Xavier District of Tohono O’odham Nation near Sahaurita, Arizona. The facility did not discharge any wastewater to waters of the United States during the previous permit term. The potential receiving water body is an unnamed wash that flows to the Santa Cruz River in a segment located between the Tubac Bridge and the Roger Road WWTP. This permittee has been classified as a minor discharger.
EPA is also soliciting comments regarding issuance of a Clean Water Act Section 401 water quality certification for this permit. Under Section 401, a federal agency may not issue a permit that may result in any discharge into waters of the United States unless a state or authorized tribe where the discharge would originate issues a 401 certification verifying compliance with existing water quality requirements or waives the certification requirement. For permits on tribal lands, if a tribe does not have authority to issue a 401 certification, EPA makes the determination regarding the 401 certification. The Tohono O’odham Nation does not have authority to issue 401 certifications. For additional information on 401 certification, see Overview of Certification under Section 401 of the Clean Water Act.