Northwest Alloys, Addy

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

Water quality permit

Comment period: Sept. 22 – Oct. 29, 2021

We invite you to comment on the proposed renewal of the State Waste Discharge water quality permit for Northwest Alloys, Inc. in Addy. We propose to renew the permit to continue to allow land treatment of commingled wastewater on nearby fields used for growing crops. When the comment period ends, we’ll review the comments received and make a final decision.

If we determine there is significant public interest during this comment period to hold a hearing, it will take place Oct. 21, 2021, starting at 6:00pm, online via WebEx. The main purpose of the public hearing is to submit verbal comments. To express interest in a hearing, contact Angie Fritz no later than Oct. 15, 2021.

Angie Fritz
Industrial Section
P.O. Box 47600
Olympia, WA 98504-7600

If we do not receive significant interest, the public hearing will be cancelled. Please check this web page for updates.

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.