Model Toxics Control Act

The Model Toxics Control Act (MTCA) is Washington’s environmental cleanup law. MTCA funds and directs the investigation, cleanup, and prevention of sites that are contaminated by hazardous substances. It works to protect people’s health and the environment, and to preserve natural resources for the future.

There are about 14,000 known or suspected contaminated sites in Washington — and the list keeps growing. Thanks to cleanup efforts funded by MTCA, more than 7,700 of these sites are already cleaned up or require no further action.

The Hazardous Substance Tax helps pay for this cleanup work. Voters approved a tax on hazardous substances (such as petroleum products, pesticides, and other chemicals) to pay for cleanups. Under MTCA, we might also recover penalties or require polluters to pay for cleanups and our oversight.

Rules and policies put MTCA into action. We’ve developed rules and policies that set cleanup standards and other requirements. These make sure cleanups protect your health and the environment.

The Toxics Cleanup Program is one of several Ecology programs that receive funds from MTCA. The Toxics Cleanup Program has primary responsibility for implementing and enforcing MTCA. They develop MTCA’s rules, policies, and guidance, and oversee or manage most of the cleanups in Washington. They also manage a grant program that helps local governments clean up contaminated sites in their communities so they can put abandoned properties back into use.

MTCA is Washington's cleanup law

The Model Toxics Control Act (MTCA) is one of several environmental laws in Washington. Known as the state’s cleanup law, MTCA governs the cleanup and prevention of contaminated sites that can threaten people’s health and the environment.

MTCA’s main purpose is “to raise sufficient funds to clean up all hazardous waste sites and to prevent the creation of future hazards due to improper disposal of toxic wastes into the state’s lands and waters.” (RCW 70A.305.010).

MTCA evolved from citizens’ Initiative 97 in 1988 and became law in 1989. It's been substantially amended more than 20 times (most recently in 2019) but its key principles remain in place today:

  • Polluter pays
  • Cleanups should be as permanent as possible
  • Public participation is crucial
  • Processes should demonstrate a bias toward action, permanence, and innovation

What's the difference between the MTCA and SMS rules?

MTCA Cleanup Regulations (also called the MTCA Cleanup Rule) applies to all cleanups, whether they're upland cleanups on land or in groundwater, or sediment cleanups in freshwater or marine environments. We published the first MTCA Cleanup Rule in 1991. We are updating this rule in a series of rulemakings that will take several years to complete. In 2023 we completed the first rulemaking, which focuses on procedures for conducting cleanups. Learn more at Chapter 173-340 WAC rulemaking and updating the cleanup rule.

Sediment Management Standards apply only to cleanups in freshwater and marine environments. We published the first SMS rule in 1991 and most recently amended it in 2013. Learn more about our sediment cleanups.

Programs and agencies with MTCA regulatory oversight

Find cleanup policies and guidance