Contaminated groundwater and storm water are still seeping off two former military bases in Bucks and Montgomery Counties, and the toxic chemicals that leaked from the bases and contaminated drinking water in adjacent neighborhoods for some 50 years have since been detected in drinking wells farther from the bases.

At least 22 other towns have joined the list of places with some level of contaminated water since residents in Horsham, Warrington, and Warminster learned in 2014 that their water was tainted by chemicals used in firefighting foams at the bases, according to interviews and a review of information shared by area municipalities and water companies.

At meetings this month, residents learned new details about community health testing that revealed above-average levels of chemicals in their blood and were told that the Navy has not finalized its plan to treat the contaminated soil and water that could still threaten drinking water.

Meanwhile, the community of affected people has grown beyond the original 70,000 in towns bordering the Naval Air Station and Horsham Air Guard Station in Willow Grove and former Naval Air Warfare Center in Warminster.

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“Everybody’s just thinking it’s our problem, but maybe it’s other people’s problem also,” one unidentified Warminster resident told the crowd at Wednesday’s state Health Department meeting in Fort Washington.

Her husband’s blood showed significantly higher chemical contamination than hers, she said, even though they had lived together in their house for 35 years. They wondered if he might have also consumed tainted water growing up in nearby Churchville.

The chemicals, known as per- and polyfluoroalkyl substances, or PFAS, were in firefighting foams used at bases and other airport sites nationwide but are also present in many modern-day products and have been linked to cancer, fertility problems, liver damage, high cholesterol, and other health problems.

As contamination has spread in communities across the country, so has fear about its effects — often with a lack of answers for the questions residents most want answered. At meeting after meeting, public officials have said they can’t predict exactly how or whether the chemicals may impact individuals’ health.

Compounding the concern is that the military continues to formulate its treatment plan, even as the plume of tainted groundwater continues to move.

“Once [the chemicals] are in the groundwater it’s really hard to stop the spread, and treating them is even more difficult,” said Christopher Higgins, a leading researcher on PFAS and a professor at the Colorado School of Mines. He predicted that PFAS will keep showing up in water supplies over time as groundwater and surface water move.

Upper Dublin, Bensalem, Cheltenham, and Northampton are among the area towns with wells that at some point have been sampled with levels of PFAS at least 20 parts per trillion. In Vermont, which has the strictest water-safety regulation in the country, that level would be deemed unsafe.

But the 20 parts per trillion figure is slightly less than one-third the amount deemed potentially harmful by the Environmental Protection Agency, which set a health advisory level for the chemicals of 70 parts per trillion in drinking water.

Given the prevalence of the chemicals in everyday items, pinpointing the sources for all contamination is likely impossible. Other, nonmilitary sources of contamination have been detected across the country. One national study revealed that 28 percent of water systems surveyed had PFAS at 5 parts per trillion or higher.

The military has taken responsibility for contamination in Horsham, Warrington, and Warminster, where it has been working to address the problem. Those sites are among nearly 400 military bases being tested for contamination — an effort that will take years and will cost millions.

When the groundwater was sampled at the Air National Guard base in Willow Grove in March, PFAS was significant at 92 percent of the spots sampled. In a few places, the levels were astronomically high.

And for storm water, the military has installed a filter that has lowered the chemical level in Neshaminy Creek — but it only treats a portion of the water coming off the base, said Chris Crockett, chief environmental engineer for Aqua Pennsylvania. Aqua sampling has shown that some water pouring out is still high in PFAS, something military officials acknowledged this month.

“Until we see those major sources cleaned up and remediated,” Crockett said, ”and see that there is nothing — that the groundwater around the base is being pumped and treated and not being allowed to spread anywhere and that the water running off or coming out of the ground and leaving the base is contained — we will always have a high level of vigilance.”

At the Willow Grove base, the Navy plans to start pumping and treating groundwater next year as part of a test program, said Willie Lin, base environmental coordinator with the military’s Base Restoration Advisory Council. The Navy is set to release a draft report this month detailing what’s known about groundwater contamination, and is preparing to make recommendations to address storm water systems, he said.

“The Navy remains focused on ensuring the drinking water supply in the communities impacted by our use of PFAS is below” the EPA’s health advisory and will comply with any future limits set by state or federal environmental regulators, Lin said.

The Pentagon has pledged to take care of contamination where it exceeds the EPA advisory level, but treatment of the chemicals isn’t required by any federal regulations. Pennsylvania is catching up to other states that have taken independent steps, including sampling water systems and setting drinking water standards. It hopes to unveil a plan to sample water systems around the state early next year.

In New Jersey, which has more restrictive water-safety guidelines than the EPA, officials found 48 public water systems that tested above the state’s maximum contaminant levels for three types of PFAS compounds. This week, a state panel in New York recommended making its already-strict drinking water standards even stricter.

Until Pennsylvania acts, water utilities and municipal officials here are left with unexpected decisions about how to respond. In Horsham, Warrington, and Warminster, officials decided to make sure the two types of PFAS originally found there were undetectable in all water supplies. But that came at a cost to consumers — reflected in their water bills — and isn’t something all towns can afford.

The highest level of contamination found in any of the Ambler Water Department’s nine wells was 17 parts per trillion — still safe to drink, by both Vermont and EPA standards.

But if the borough wanted to get that number to zero, it would cost more than $5 million, Borough Manager Mary Aversa wrote in a letter this fall to Upper Dublin Township, which relies on Ambler’s water supply to serve some of its residents.

Upper Dublin, like other eastern Montgomery County towns, also gets water from Aqua Pennsylvania, which this summer shut down two wells with contamination below the EPA guideline that had been identified as early as 2016. Abington, Cheltenham, and Springfield Townships were also in the affected area.

“The health of our people is at stake,” state Sen. Art Haywood (D., Montgomery) wrote to federal regulators in an August letter. “Now is the time for all those who are responsible to end the release of the PFAS contamination from the [Willow Grove base] to protect the health and safety of residents and our environment.”

In other towns, the same issues have sprung from different sources. State officials have identified two nonmilitary sites in Bucks County — one affecting East Rockhill and West Rockhill Townships and another affecting Doylestown, Plumstead, and Buckingham — that caused water contamination. Wells have been shut off as officials investigate the causes of contamination.

Mark Cuker, an environmental lawyer, was already working on lawsuits against the federal government and firefighting foam manufacturers on behalf of Horsham, Warrington, and Warminster residents when he learned in 2016 that his own water in Upper Dublin was contaminated with PFAS.

“Now it’s me, it’s not my clients. It’s me,” he said. He recalled the thought that went through his mind: “Is this really happening?”