Toxics Cleanup Program’s statutes and regulations

The Toxics Cleanup Program (TCP) operates under two major sets of laws that govern:

  • Contaminated site cleanups, and
  • Underground storage tanks and their operation, for tanks containing petroleum or other hazardous substances.

Our authority begins when the Legislature passes a bill or Washington voters pass an initiative. Rules fill in the details and help make statutes work for the majority of people. This page connects you to the specific laws that direct TCP's work, and all the laws that direct our work. For help interpreting TCP’s laws, visit policies and guidance for site cleanups.

Statutes, regulations, and rules... what’s the difference?

Statutes are passed by the Legislature in bills or by voters in initiatives. Statutes can get long and often don't fill in all the details, and rulewriters can't always anticipate how statutes will work. Agencies like ours are responsible not only for carrying out statutes, but filling in those gaps and dealing with the unexpected by promulgating rules.

Regulations are also called rules. Rules can't change statutes, but they can clarify things found in statutes that are unclear or confusing. Washington's Legislature and voters can always change rules they don’t like by passing new bills or initiatives.

Our policies and guidance interpret these statutes and regulations and help you clean up sites.

Which one is “the law?”

All of them!  Statutes, rules, and the court decisions that interpret them are all parts of “the law.” Since rules are usually more specific than statutes, they're a good place to start when you're figuring out what the law says you can or must do. For specific laws that direct the Toxics Cleanup Program's work, see the table below. For a list of all laws that direct Ecology's work, visit laws, rules, & rulemaking

What are RCWs and WACs?

People often refer to RCWs (for statutes) and WACs (for rules) when discussing Washington's laws. These are bound and coded into two separate publications:

Contaminated site cleanups: statutes and rules that describe how and when cleanups must be done




Cleanup of Contaminated Sites
Explains the cleanup process and standards. 

Chapter 70A.305 RCW: Model Toxics Control Act (MTCA)

Chapter 173-340 WAC: MTCA Cleanup Regulations (also known as the MTCA Cleanup Rule). We are revising this rule in a multi-year process. Learn more at Chapter 173-340 WAC and MTCA Cleanup Rule exploratory rulemaking.

Chapter 173-204 WAC: Sediment Management Standards

Public Funding for Cleanup
Describes what grants are available for remedial actions.

RCW 70A.305.190: Model toxics control capital account

Chapter 173-322A WAC: Remedial Action Grants and Loans

Revenue for Cleanup
Explains about the tax that supports the Toxics Cleanup Program.

Chapter 82.21 RCW: Hazardous Substance Tax

WAC 458-20-252: Hazardous Substance Tax

Chapter 82.21.020(1)(d) RCW Additional substances

Chapter 173-342 WAC: Additional Taxable Hazardous Substance List

Underground Storage Tanks: statutes and rules that explain requirements for operating an underground storage tank (UST) and cleaning up releases from USTs




Underground Storage Tanks program
Explains the requirements for operating an underground storage tank system.

Chapter 70A.355 RCW: Underground Storage Tanks

Chapter 173-360A WAC: Underground Storage Tank Regulations

Leaking Underground Storage Tank (LUST) cleanup
Explains the special cleanup requirements for leaking underground storage tanks.

Chapter 70A.305 RCW: Model Toxics Control Act (MTCA)

WAC 173-340-450: Releases from Underground Storage Tanks

Reinsurance for regulated Underground Storage Tanks (PLIA)
Explains Pollution Liability Insurance Agency’s (PLIA) reinsurance program for regulated USTs.

Chapter 70A.325 RCW: Underground Petroleum Storage Tanks

Title 374 WAC: Pollution Liability Insurance Agency

Insurance for heating oil tanks (PLIA)
Explains PLIA’s insurance program for heating oil USTs.

Chapter 70A.330 RCW: Petroleum Storage Tank Systems--Pollution Liability Protection Act

Title 374 WAC: Pollution Liability Insurance Agency

Revenue for PLIA’s programs
Explains the funding source for PLIA’s programs.

Chapter 82.23A RCW: Petroleum Products-Underground Storage Tank Program Funding

WAC 458-20-281: Petroleum Product Tax