In 2010, the TransAlta power plant agreed to reduce mercury and nitrogen oxide emissions. The agreement required TransAlta to burn low sulfur coal to protect and improve visibility in national parks and wilderness areas. In 2011, the governor signed a bill requiring TransAlta to change to cleaner fuel and reduce greenhouse gas emissions. At the end of 2020, TransAlta stopped using one of two coal-fired boilers. They will stop using the second one by the end of 2025. In the meantime, they will use nitrogen oxide-reducing technology on the remaining boiler. This was a significant step to reduce regional haze.
In December 2010, we revised the Regional Haze State Implementation Plan (SIP) which covers 2005–2018. As the basis for future regional haze state implementation plans, this plan:
- Determined baseline (2000-2004) visibility conditions for Washington's mandatory Class 1 Areas.
- Developed a long-term strategy to improve visibility.
- Provided inventories of emissions causing a visibility problem.
- Analyzed natural and human-caused sources of haze for Washington's mandatory Class 1 Areas.
- Established reasonable progress goals for 2018 for Washington's mandatory Class 1 Areas.
- Determined and required upgrading emission technology (Best Available Retrofit Technology, BART) at large industrial sources.
In January 2022, we revised the Regional Haze State Implementation Plan (SIP) which covers 2018–2028 and includes a progress report for 2014–2018. This second plan:
- Establishes visibility goals for 2028 for Washington’s mandatory Class 1 federal areas.
- Develops a long-term strategy to improve visibility.
- Provides inventories of emissions causing a visibility problem.
- Analyzes natural and human-caused sources of haze in Washington’s mandatory Class 1 federal areas.
- Selects and evaluates the largest emitting stationary sources for potential emission controls.