How did people come into contact with PFAS from firefighting foam?

How does firefighting foam get into drinking water?

AFFF is a foam made to fight fuel fires. Many versions contained PFAS.

The federal health agency ATSDR studied communities near such sites. At those sites, PFAS from the foam entered the ground, moved off-site and affected drinking water. Where a town drew its water from that groundwater, the chemicals reached its wells.

Two things follow, and they shape these pages. The contamination is local: it depends on which well served which street. It is also often historical. Where wells were shut down or treated, a sample taken today says little about earlier years.

Nobody can say exactly when the water first carried PFAS. Near Peterson Air Force Base, PFAS was first detected in town wells in 2013. Health officials say the contamination likely began earlier. So these pages keep apart what was measured, and when, and say where records are missing.

What if you handled the foam at work?

In the AFFF lawsuits, handling the foam is its own exposure route. It is separate from drinking contaminated water. A court order and its complaint form call it direct exposure: the use or handling of AFFF.

The same order names three kinds of work: firefighting, military service, and other jobs with regular contact with the foam. It asks for work records, not water records. These are military service records, employment records or tax forms. The records should show the job before the diagnosis. They should also cover the whole period of exposure you claim.

There is no water system to look up for this route. The full list of records, for both routes, is under What should you bring to a lawyer?

Is the foam still in use?

A defense law for 2020 told the military to stop using AFFF at its bases after October 1, 2024. Use on ships was exempt. The law allowed two one-year waivers.

The Department of War used the first waiver in August 2024, moving the date to October 1, 2025. In May 2025, it said it would use the second, to October 1, 2026 (briefing, page 2).

A defense law for 2026 (section 315) changed the rule. On July 31, 2026, the Department certified a new one-year waiver. It moves the deadline to October 1, 2027. The letter refers to two waivers under the new rule. This was one of them.

The Department says it stopped buying AFFF for land-based use in October 2023. It says it uses AFFF for training or testing only when the foam can be fully contained.

Civilian airports follow different rules. In January 2023, the FAA said certified airports could keep using AFFF. The FAA itself would not require them to switch. It told airports to check state and local rules as well. So for some firefighters, contact with the foam may not lie only in the past.

What about turnout gear?

Some firefighters also blame their turnout gear. Cases that blame both the foam and the gear belong to the AFFF lawsuits. Cases about the gear alone are grouped separately, in Minnesota. Their claims and the research are on a separate page: What do the lawsuits over PFAS in firefighter gear claim?

Which places have we documented?

• Peterson Air Force Base, Colorado
  Water systems: Security, Widefield, Fountain, the Security Mobile Home Park, and private wells. Shutdowns and treatment differ by system; the place page lists each one. Highest PFOS result in our Peterson data export, without a laboratory qualifier: in ng/L: 1,130, sampled September 3, 2024. The sampling point is listed without a treatment system. That is not necessarily what came out of a tap.
• Willow Grove and Warminster, Pennsylvania
  Two former Navy bases and an Air National Guard base. Water systems: Horsham, Warminster, Warrington, North Wales, Aqua, and private wells. Highest PFOS result since 2021, without a laboratory qualifier, in ng/L: 864, sampled October 29, 2021. It is a single result; the next highest there is 51.1. Before treatment began, a private well held 5,200.
• Fairchild Air Force Base and the West Plains, Washington
  Airway Heights and private wells in the West Plains. Washington's ecology department names two more sources: Spokane International Airport and a county fire station. Highest PFOS result since 2021 without a treatment system or a laboratory qualifier, in ng/L: 671, sampled October 7, 2022. In 2017, a city well held 1,200.

How are these pages put together?

• Measurements come from the Department of War's own off-base drinking water testing results. We download the full result file instead of reading the web view.
• Tables of highest values rank results the laboratory reported without a qualifier. Estimated values, flagged "J", are shown separately next to them.
• We name water systems by their PWSID, the ID used in official records.
• Every claim about the lawsuits or the data carries a source, right where it is made.

Others publish PFAS maps too. We add one step: we set the measurements next to the years of shutdowns and treatment. That helps you compare them with the years you lived at an address. It cannot tell you what your own tap delivered in a given year.

How do PFAS results compare with the limits?

The EPA set the first enforceable federal PFAS limits in April 2024. They apply to public water systems. Systems must meet them by April 2029. The EPA lists the limits as follows, in ng/L:

Status as shown on the EPA's pages in October 2026. The comment period on both proposals closed on July 20, 2026. We will update this table when the EPA decides.

Did older results break these limits?

A result from before 2024 did not break a limit that came later. The limit is a yardstick for what the water contained. It is not a finding against a utility. A single result from a private well is not a violation either. The limits apply to public systems.

What does the Department of War do for private wells?

On September 3, 2024, the Department set an action level for private wells at three times the federal limits. That is 12 ng/L for PFOA or PFOS, and 30 ng/L for PFHxS, PFNA or HFPO-DA. For mixtures, it is a hazard index of 3. Where the Department is the known source, it starts interim action at or above that level. Wells below it are to be addressed later, in the regular cleanup process. Because the level is tied to the federal limits, it may change with them.

Do states set their own limits?

Some do. Pennsylvania, for example, has its own limits for PFOA and PFOS. Each place page names the state values that apply there.

What does PFAS exposure do to health?

The federal health agency ATSDR reports that studies of exposed populations suggest associations between certain PFAS and:

• higher cholesterol levels
• lower antibody response to some vaccines
• changes in liver enzymes
• pregnancy-induced high blood pressure and preeclampsia
• small decreases in birth weight
• kidney and testicular cancer

A 2022 review by the National Academies went further on one point. It found sufficient evidence of an association with kidney cancer.

The IARC classifies PFOA as carcinogenic to humans and PFOS as possibly carcinogenic. That rates the hazard in general. It says nothing about a single person's illness.

Can you shower, cook and clean with PFAS water?

Can PFAS get in through the skin?

The agencies say skin is a minor route. That position is being tested. In 2024, a University of Birmingham team exposed 3D human skin models to 17 PFAS for 36 hours. Most of them crossed the skin barrier. For PFOA, about 13.5% passed through, and a further 38% stayed in the skin.

Two further points matter. The lead author states that the doses used were higher than people normally encounter. A 2025 study tested 30 PFAS on real human skin for 24 hours. None of the long-chain PFAS penetrated the skin. Four short-chain ones did, at rates between 1.1% and 4.8%. PFOS, PFOA and PFHxS are all long-chain.

So the old assumption that skin is simply a barrier no longer holds for every PFAS. That is truest for the short-chain ones. These were lab tests; none of them tested showering. The agencies still rate drinking as the main route. We will change this section if the evidence changes.

Can PFAS evaporate out of the water into the air?

Some can. A group of PFAS known as neutral precursors can pass from water into air. How much depends on the compound. ATSDR's toxicological profile describes them as volatile. They can travel long distances in the air and then break down into PFOA and PFOS. This is one explanation for PFOA and PFOS in the Arctic, far from where they were made. Ocean currents are another.

PFOS, PFOA and PFHxS themselves behave differently. In water they carry an electrical charge, which keeps their vapour pressure low and their water solubility high. In ordinary drinking water, they hardly turn into vapour.

Whether volatile PFAS were tested near a site, and found, is a local question. Each place page answers it where the data allows.

There is no approved medical treatment to remove PFAS from the body. The body does clear them, but slowly — for the long-chain compounds, over years.

What are the AFFF lawsuits?

More than 10,000 AFFF cases have been grouped before one federal judge in South Carolina. This is MDL 2873.

The plaintiffs' leadership is pursuing six conditions:

• kidney cancer
• testicular cancer
• ulcerative colitis
• thyroid disease
• liver cancer
• thyroid cancer

Handling the foam at work and drinking contaminated water are separate exposure routes. Some people fall into both. Each route is explained above: handling the foam and drinking water.

Two of the six, thyroid cancer and liver cancer, are under review. The court is weighing challenges to the experts on whether PFAS can cause them. Under the court's order of August 31, 2026 (CMO 33F), briefing runs into January 2027. No decision has been made.

Each place page shows the local records an exposure claim may rely on. Which rules apply to a case also depends on when it was filed. We do not assess individual claims, and we are not a law firm.

What if your diagnosis is not one of the six?

The list is what the plaintiffs' leadership chose to pursue, not a rule about who may sue. Some other diagnoses fall under separate, stricter court rules. Which rules apply depends on the condition — ask a lawyer.

How long do you have to bring a claim?

Deadlines differ by state and by type of claim. The clock may start at the injury, or only once it was discovered or should have been. Which rule applies depends on the state and the facts. Some laws also set an outer limit. It counts from the defendant's act, even before anyone is injured. Ask a lawyer licensed in your state early.

Why keep your own medical records?

This is worth doing whether or not PFAS ever concerns you. Records that live only in one clinic's system are records you cannot show to the next doctor.

The National Academies' clinical guidance tells doctors to take an exposure history when PFAS exposure is possible. ATSDR makes the same point in its factsheet for clinicians. How long, how much and by which route someone was exposed changes what the doctor does next. You are the only person who can supply the addresses, the jobs and the years.

What is worth having a copy of:

• diagnoses, with the date each was first made
• lab results and imaging reports
• surgical and hospital discharge summaries
• a current list of medications and allergies
• where you lived and worked, and in which years

In the US you have a right to a copy of your records under HIPAA. Providers must generally respond within 30 days, and may charge only a reasonable, cost-based fee.

Should you ask for a PFAS blood test?

Health bodies weigh this differently. The National Academies advise doctors to offer PFAS blood tests to people likely to have had high exposure. That includes exposure at work and living in a contaminated area.

ATSDR is more cautious. It says blood test results cannot guide treatment or predict future health problems. A result also does not show where the PFAS came from, or whether it caused an illness. Whether a test makes sense for you is a question for your doctor.