Aqueous film forming foam (AFFF)

fire extinguisher
Aqueous film-forming foam (AFFF) is a type of foam used to fight fires. Fire departments use AFFF to fight liquid-based fires (i.e., those started by oil, gasoline, or other flammable liquids).

AFFF is highly concerning because it contains PFAS (per- and polyfluoroalkyl substances). PFAS are toxic chemicals known to negatively impact human health and do not easily break down in the environment, waterways, wildlife, or human bodies.

  • PFAS is linked to negative health impacts in humans, including cancer.
  • AFFF is the leading cause of PFAS contamination in drinking water.

As of 2018, Washington passed a law that restricts AFFF because of the dangers of PFAS.

Learn how PFAS gets into the environment

What are the dangers of AFFF?

AFFF contains PFAS. AFFF is considered the main cause of PFAS-contaminated drinking water in the United States.

PFAS poses risks to humans and wildlife, such as:

  • Reproductive impairment
  • Increased cancer risk
  • Reduced immune system response

It is estimated that nearly all Americans have some amount of PFAS in their blood.

How does AFFF contaminate drinking water with PFAS?

The most common ways that PFAS have contaminated drinking water is by way of using AFFF for fire suppression activities, such as:

Once PFAS is released into the environment, it is difficult to clean up because they:

  • Easily dissolve in water.
    PFAS are highly mobile and can quickly contaminate groundwater, drinking water, and other natural areas.
  • Do not break down naturally.
    PFAS build up in the environment over time with no natural way to be removed, which may increase our risk of exposure to PFAS for hundreds or thousands of years.

Why does AFFF contain PFAS?

PFAS are the chemicals that create the “film” in aqueous film-forming foam. They put fires out by cutting off the oxygen between the flammable liquid and air, which is what keeps fires burning once ignited.

PFAS are used because of their ability to:

  • Resist heat.
  • Easily dissolve in water.
  • Spread quickly so they put out fires faster.

What is Ecology doing about AFFF?

In 2018, the Washington State Legislature passed a law that restricts AFFF. In Washington state, AFFF is now banned for most purposes. It can no longer be:

  • Manufactured.
  • Sold.
  • Used for fire training.

AFFF is still allowed for emergencies and actual fire situations that require it until an alternative is found.

What's happening now?

To help fire departments decrease the amount of AFFF they store on-site, we are developing a:

A draft EIS is expected to go out for public comment Winter 2023.

Timeline of past and future activities


Reducing AFFF at airports

Under federal law, commercial airports in Washington must test their ability to dispense AFFF (which contains PFAS) each year. These tests:

  • Can disburse thousands of gallons of PFAS on the ground.
  • If not carefully collected, the PFAS from AFFF can contaminate groundwater and drinking water.

In 2021, our input-based test box program at airports started. It provides airports with funds to purchase equipment that allows them to test their firefighting capabilities without the need to put AFFF on the ground.

Watch our video about input-based test boxes to learn more.