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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 more than 12,500 known or suspected contaminated sites in Washington — and the list keeps growing. Thanks to cleanup efforts funded by MTCA, more than 6,600 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 70.105D.010).

MTCA evolved from citizens’ Initiative 97 in 1988 and became law in 1989. It's been amended 23 times (most recently in 2013) 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 is a hazardous site?

We often use the terms site, hazardous sitecleanup site, and contaminated site interchangeably. A site is where we’ve confirmed one or more releases (or threatened release) of a hazardous or dangerous substance that needs to be cleaned up. There are more than 12,500 known or suspected contaminated sites in Washington. MTCA helps us address them. 

MTCA is funded in four ways

  1. Taxes. Voters authorized a tax on hazardous substances to help pay for cleanups.
  2. Cost-recovery. We recover cleanup costs from potentially liable persons.
  3. Penalties. We collect or recover penalties under the MTCA law.
  4. Other sources. The legislature may transfer other funding for cleanup work.

Revenues from these sources are deposited into three accounts: State Toxics Control Account, Local Toxics Control Account, and Environmental Stewardship Account. Collectively, these are called the MTCA accounts. Learn how we’re using these funds in our reports to the Legislature.

Why is MTCA important?

More than 6,600 contaminated sites in Washington have been cleaned up with MTCA funds and collection authority since it became law in 1989. That’s more than half of the state's 12,500+ cleanup sites. MTCA’s role is becoming even more essential because about 300 new sites are reported each year.

MTCA powers our work to investigate, clean up, and prevent hazardous waste. Cleanups protect people’s health by removing toxic chemicals from the environment, like arsenic from playground soil or methane gas from a solid waste landfill. Cleanups are preserving wildlife habitat for future generations, spurring new economic developments, and putting abandoned properties back into use.

MTCA — and every person involved in a cleanup — make these transformations possible.

How do we put MTCA into action?

We developed regulations (called “rules”) to implement the Model Toxics Control Act. They set standards and requirements for contaminated site cleanups. Rules ensure that cleanups are protecting people’s health and environment. If you’re cleaning up a contaminated site in Washington, you’ll need to meet the requirements of:

Dangerous waste cleanups and management also need to comply with Washington's hazardous waste management law and dangerous waste regulations

We have policies and guidance to help you meet these requirements.

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

MTCA Cleanup Regulations (also called MTCA rule) applies to all cleanups: upland cleanups on land or in groundwater, and sediment cleanups in freshwater or marine environments. We published the first MTCA rule in 1991 and most recently amended it in 2007.

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.

Which programs and agencies have MTCA regulatory oversight?

  • Toxics Cleanup Program has primary responsibility for implementing and enforcing MTCA. The program develops rules and guidelines that govern cleanups. It manages the Remedial Action Grant program that funds cleanups by local governments. It also oversees or manages most cleanups in Washington.
  • Hazardous Waste and Toxics Reduction Program oversees cleanups of releases from hazardous waste treatment, storage, and disposal facilities that are regulated under the Hazardous Waste Management Act (Chapter 70.105 RCW). They also manage Dangerous Waste Permits.
  • Solid Waste Management Program oversees cleanups of releases from permitted landfills and large industrial facilities — such as pulp and paper mills, aluminum smelters, and petroleum refining — and distribution systems.
  • Nuclear Waste Program ensures that cleanup of contaminated sites on the Hanford Nuclear Reservation is consistent with state law.
  • Pollution Liability Insurance Agency provides technical assistance to people who independently clean up sites contaminated by petroleum from leaking heating oil tanks. This includes written opinions on sufficiency of cleanups based on MTCA standards. In 2017, the legislature authorized PLIA to expand its existing technical assistance program to include other petroleum storage tank sites we identify. (House Bill 1266).

MTCA resources

How we developed MTCA standards and selected cleanup actions