PFAS at cleanup sites

We have concluded that Per- and polyfluoroalkyl substances (PFAS) fall under the Model Toxics Control Act (MTCA). Releases of PFAS compounds will need to be cleaned up. In July 2022 we issued recommended soil and groundwater cleanup levels for six of the most common PFAS compounds. In June 2023 we published guidance for investigating and cleaning up PFAS contamination in Washington state. 

PFAS are a family of manufactured chemicals, most of which never disappear from the environment. They're used to make things resistant to oil and water, or to reduce friction. PFAS are a common ingredient in consumer products. 

Studies have shown that some PFAS chemicals are toxic to humans and the environment. In Washington, PFAS have contaminated some drinking water supplies. To date, most of this contamination has been linked to the use of PFAS in firefighting foam. PFAS have also been detected in surface waters, groundwater, wastewater treatment plant effluent, compost, freshwater and marine sediments, freshwater fish tissue, and osprey eggs in Washington.

Regulating PFAS

Currently, there are no established federal standards for any PFAS compounds. However, in 2022, the Environmental Protection Agency issued non-enforceable interim groundwater health advisory levels for two of the most commonly studied PFAS — perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). They also issued final health advisory levels for perfluorbutane sulfonic acid (PFBS) and hexafluoropropylene oxide dimer acid (also known as GenX). PFBS is a replacement compound for PFOS and GenX is a replacement compound for PFOA.

As part of our efforts to address PFAS contamination, we have reviewed applicable laws and concluded that PFAS compounds are hazardous substances under the Model Toxics Control Act. This conclusion is based on an evaluation of existing regulatory authority which says that compounds considered hazardous substances under the Dangerous Waste Regulations or the Hazardous Waste Statutes are also hazardous substances under MTCA.

PFAS cleanup levels

Investigating & Remediating PFAS Contamination in Washington State

The Washington Department of Health set State Action Levels (SALs) for five PFAS compounds in drinking water. Using the SALs, we developed recommended soil and groundwater cleanup levels for the same five compounds. We calculated preliminary soil and groundwater cleanup levels for a sixth compound (GenX) using EPA’s reference dose and equations in our cleanup rule. You can find these levels in our July 2022 focus sheet. Because the SALs are not enforceable, establishing cleanup levels under MTCA using the SALs needs to follow a different process than we usually use, including imposing cleanup levels on a site-by-site basis.

In June 2023, we published Guidance for Investigating and Remediating PFAS Contamination in Washington State. The draft went out for public comment from Dec. 15, 2022–March 3, 2023. The final guidance contains the comments we received, as well as our responses.

This guidance provides information and direction on:

  • Known PFAS impacts across Washington
  • Soil and groundwater cleanup levels
  • Sampling options for PFAS compounds
  • Approaches to minimize cross-contamination
  • Protective concentrations for ecological receptors, and
  • Field demonstrated treatment technologies.

It also explains how we determined the appropriate cleanup levels and how they apply to individual sites.

A long-term problem

Although Washington has made progress in dealing with PFAS, this is a long-term problem. Efforts to reduce the use of PFAS and to prevent additional releases into the environment will continue to require resources into the future. We are working with other agencies, the public, and stakeholders to figure out the best way to clean up source areas and reduce exposures.

PFAS releases into the environment

If PFAS compounds are released to the environment and might pose a threat to human health or the environment, they must be reported to Ecology within 90 days of discovery. As with releases of other hazardous substances, the next step will often be an assessment of whether further action is necessary. If so, follow-up is usually a site investigation and, if needed, a cleanup.