All areas in Washington state must meet national air quality standards for the six most common air pollutants. One of those pollutants is sulfur dioxide (SO2).
- From 2017 – 2019, we worked with the Northwest Clean Air Agency to evaluate air quality data from Whatcom County. Data from monitors near Intalco showed SO2 did not meet the national standard.
- In December 2020, the U.S. Environmental Protection Agency (EPA) designated part of Whatcom County near the smelter to be in nonattainment for this standard. (EPA's decision and response to comments).
Attainment plan
We sent the final plan to bring the area back into attainment (called a State Implementation Plan revision) to EPA for approval and finalized the associated Agreed Order.
The plan describes actions the facility will have to take, including:
- Installing and operating new SO2 controls
- Merging and increasing the height of stacks
- Limit facility-wide and unit-specific SO2 emissions
- Different scenarios if the facility should restart before or after April 30, 2025
The Northwest Clean Air Agency, Intalco, and Blue Wolf Capital Partners (a private equity firm interested in purchasing and reopening the facility) participated in the development of the plan.
Next steps
EPA’s oversight of the plan is required under the federal Clean Air Act, and it will provide an opportunity for public comment before making a final decision. Once approved by EPA, the requirements of the attainment plan and Agreed Order become federally enforceable. The Agreed Order requirements are in effect and will be implemented, regardless of EPA's timeline for review and approval.
Why this is important
Breathing elevated levels of SO2 causes inflammation and tightening of airways and can trigger asthma symptoms. SO2 typically dissipates very quickly, but people living or working close to sources may be exposed to short-term levels that pose a risk to those with pre-existing breathing or health issues. SO2 pollution also decreases visibility in the form of haze and contributes to acid rain.
Join our sulfur dioxide attainment email list to learn more about our efforts to monitor and evaluate SO2 levels in Washington.
Updated Jan. 3, 2023
We issued final air quality Agreed Order 18216 (response to comments) for the Intalco aluminum smelter on Jan. 22. 2021.
This facility temporarily closed (curtailed) in Aug. 2020. The order requires it to:
- Prepare and submit a Four-Factor Analysis at least 180 days before restarting any potlines.
- Install and put in place reasonable air pollution reduction measures identified in the analysis within three years of approval by Ecology.
A Four-Factor Analysis assesses and compares potential air pollution (emissions) control technologies for cost, time needed to install the control, energy and non-air quality impacts, and remaining useful life of equipment. The controls selected will reduce sulfur dioxide emissions and become part of Washington’s air quality plan to improve air quality by reducing regional haze — the human-caused particles in the air from activities such as industrial operations and burning of fuel — to improve visibility.
The air pollution reductions expected will be reported in the Regional Haze plan.