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Air Quality Program

Clean Air Rule

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Washington’s water supply, air quality, and infrastructure are at risk because of climate change. Ecology adopted a rule under our state’s Clean Air Act to reduce carbon pollution to do our part to help slow climate change. The Clean Air Rule regulates the businesses who are responsible for about two-thirds of carbon pollution in Washington, such as transportation, refining, and manufacturing.

Official rule documents

Determining carbon markets for the Clean Air Rule

We gathered feedback to help us determine which carbon markets to consider for the Clean Air Rule. A carbon market is a program designed to reduce greenhouse gas emissions through the trading of credits called allowances.

Organizations covered by the rule are given several ways to comply. One way to comply is to obtain carbon credits (allowances) that come from an approved carbon market outside of Washington. The rule requires that we determine which markets to approve based on three criteria:

  1. Allowances are issued by an established multi-sector greenhouse gas emission reduction program.
  2. Covered parties in the Clean Air Rule are able to purchase allowances within the market.
  3. Procedures used to determine allowances must be compatible with those used in Washington's greenhouse gas reporting program.

Earlier this year we sent out a survey to gather information about domestic and international carbon markets. We used the responses, in addition to the criteria above, to develop an initial list of carbon markets to consider.

Potential markets, or countries with markets, include:

  • European Union Emission Trading System
  • New Zealand
  • South Korea
  • Western Climate Initiative (includes California and Canadian province of  Quebec)

We gathered comments on the list, both online and at a listening session on Oct. 2, 2017. You can read the comments we received online. No comments were given at the listening session, although you can watch the presentation by Ecology staff.

We are currently reviewing comments and continuing our evaluation of potential markets.

If you have questions please contact Bill Drumheller, at (360) 407-7657.

Who is covered under the Clean Air Rule?

In 2017 organizations that are responsible for 100,000 metric tons of carbon pollution annually are required to cap and gradually reduce their emissions. Every three years, the threshold is lowered by 5,000 metric tons and more emitters are brought into the program. By 2035 the threshold will reach 70,000 metric tons where it will remain.

Businesses categorized as energy-intensive, trade-exposed industries and fuel importers begin participating in the program in 2020.

The types of organizations covered by the rule include:

  • Natural gas distributors
  • Petroleum product producers, i.e. refineries, and importers
  • Metal, cement, pulp and paper, and glass manufacturers
  • Power plants
  • Waste facilities

List of potential Washington regulated businesses

Clean Air Rule

Report your greenhouse gas emissions and emission reduction units. View verification requirements and find a verifier.


Energy-Intensive, Trade-Exposed Businesses (EITEs)

Find guidance for energy-intensive, trade-exposed businesses to comply with the Clean Air Rule.


Meeting Clean Air Rule Requirements

Learn how organizations can reduce their emissions and get emission reduction units.



Read about the Clean Air Rule's economic impact, how the rule accommodates business growth and the Environmental Justice Committee.

Video gallery

Reducing pollution

Rule update

Director Bellon's address

Preserving Puget Sound

Seeking feedback

Who's covered?


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