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Northwest Alloys, Addy

We regulate water and hazardous waste activities at Alcoa's Northwest Alloys magnesium smelter in Addy.

Facility information

This magnesium smelter operated between 1976 - 2001. The smelter is temporarily shut down and Northwest Alloys, a subsidiary of Alcoa, plans to sell the facility as an industrial site.

  • The company has completed mine closure and reclamation requirements at the site.
  • Northwest Alloys neutralizes high-pH wastewater and mixes it with stormwater, treated sanitary wastewater, and well water. They store this mixture onsite. When there is more wastewater than they can store, they use a limited amount to irrigate croplands.
  • Pond 3 stores the old wastewater from the magnesium making process. Northwest Alloys is looking into options for treatment or reuse of this water.

Permit information

Northwest Alloys location

1560A Marble Valley Basin Road, Addy, Wash.