PFAS “forever chemicals” have been detected in 33 of 46 public water locations in Philadelphia’s suburban counties, or 72% of samples, although none exceeded totals of federally suggested limits, according to an Inquirer analysis of new state data.

Statewide, however, the Pennsylvania Department of Environmental Protection found PFAS in only 35% of 114 sites tested in a broader sampling of 22 counties. Similarly, none of those exceeded the current EPA guideline of 70 parts per trillion, although some scientists contend there are no safe levels.

The Inquirer looked at results for Philadelphia, Bucks, Montgomery, Chester, and Delaware Counties. The data indicate most PFAS samples were found in Bucks and Montgomery, though that was expected because of past contamination from military bases, and that’s where the state focused most of its effort.

Drinking water of residents living near the Naval Air Warfare Center in Warminster and Naval Air Station in Willow Grove was tainted by the “forever chemicals” that leached off bases from firefighting foam.

No PFAS were detected in the Philadelphia Water Department system, although a small amount was found in a private system within the city. There was also some PFAS in Chester and Delaware Counties.

PFAS are a family of chemical compounds widely used to make coatings for products needing resistance to heat, oil, stains, grease, and water. They have been used for decades in clothing, furniture, adhesives, food packaging, heat-resistant nonstick cooking surfaces, and wire insulation.

The compounds don’t break down, and accumulate over time in the human body. There is evidence they can affect human health.

The testing carried out in 2020 was part of Gov. Tom Wolf’s executive order to address PFAS (perfluoroalkyl and polyfluoroalkyl substances) in public drinking water. The state focused most of its sampling on sources located within a half-mile of a potential source of contamination, such as military bases, fire training sites, landfills, and manufacturing facilities.

Water was sampled at both municipal water systems and nonresidential systems such as those at businesses, schools, apartments, and medical facilities.

Pennsylvania has not yet set a maximum contaminant level for PFAS but is in the process of creating one. The EPA has also not set a firm limit, only guidance.

Sampling started in 2019. Data released Friday are part of a second round of testing from 2020. The DEP has identified 493 public water system sources as potential sampling sites and is continuing to test samples from other locations.

In its recent testing, Pennsylvania looked for the presence of six PFAS compounds: PFOS, PFOA, PFNA, PFHxS, PFHpA, and PFBS. It added the total to see if they fell under the 70 parts per trillion guideline.

However, the state also tested for 12 other compounds that weren’t included in that total. There are more than 4,700 known PFAS compounds.

Bucks and Montgomery Counties have continued to be a focus since some residents of Horsham, Warrington, and Warminster took part in a 2018 pilot study that showed elevated levels of PFAS in their blood compared with the American average. Water in those communities was contaminated by the bases. A national study is underway to test adults and children in Bucks and Montgomery Counties.

Locally, the highest levels were found at a system used by WEC International in Fort Washington, Montgomery County, that had a combined total of 25.6 parts per trillion. Representatives of WEC, a Christian organization, could not be reached for comment.

Next highest were the Doylestown Water Department in Bucks County and Audubon Water Co. in Montgomery County, both at 25.3.

“We are certainly concerned,” said John Davis, Doylestown Borough manager.

Davis said the borough draws on a number of wells and the DEP sample came from one of them, though he said there’s no way to pinpoint the source of the PFAS. “We’ll probably never know,” he said.

Davis hopes that any future state regulation that sets a maximum contaminant level for PFAS includes funding for small systems like the borough’s. The EPA recommends several treatments, such as reverse osmosis, but Davis said those are prohibitively expensive.

For residents, the Environmental Working Group lists several types of home filtration systems and says activated carbon is the cheapest but reduces only one type of PFAS. Reverse osmosis is more expensive but can completely eliminate the chemicals.

Hope Grosse, cofounder of Buxmont Coalition for Safer Water, said “it’s not surprising” the state’s results showed PFAS in local public water systems. “We know that the Warminster and Willow Grove air bases are within five miles of each other and water traveled into ... Neshaminy Creek and flows in different ways.”

Grosse noted that the state did find the presence of types of PFAS that weren’t included in the totals.

For example, a sample from the Telford Borough Authority detected 87.5 parts per trillion of PFHxA that was not included in the total PFAS for the authority, which came in at 17.1 parts per trillion.

The DEP said that’s because it included only those PFAS compounds — PFOA and PFOS — that are part of the EPA’s guidance.

Grosse said Pennsylvania needs to adopt a maximum contaminant level quickly, and cited New Jersey, which set maximum contaminant levels in 2018 of 14 parts per trillion for PFOA and 13 parts per trillion for PFOS.

“Why don’t we have regulations?” Grosse asked. “Why are they taking their time? New Jersey has already figured it out, so why can’t we?”

Jamar Thrasher, a spokesperson for the DEP, said the department “will be moving forward with developing a pre-draft proposed rulemaking later this year.”

Tracy Carluccio, deputy director of the Delaware Riverkeeper Network, noted that the test results do not include private water wells, which she called “a huge flaw in the testing plan.”

“Greater than one-quarter of the population in Pennsylvania get its drinking water from private wells,” Carluccio said.

Overall, Maurice Sampson of Clean Water Action said “the numbers are sort of irrelevant” because he does not believe there is a safe level .

“We need to know how to reduce what’s in the water and eliminate its sources,“ Sampson said.