When the planes burned, the kids would come out.
Hope Grosse and her siblings would run down their Warminster street and rubberneck amid shrieking sirens. They would watch Navy firefighters shoot a dense white foam from hoses, smothering the flames that leapt up from the fenced-off lot.
When the blackened plane was cool, the children would climb the fence and jump into the burned-out cockpit, pretending to be pilots, Grosse recounted.
The plane, and the field where the Navy conducted drills, was also a playground for the Kirk Road kids back in the 1970s and '80s. They did not know then that the firefighting foam could be toxic, or that it would seep into their drinking water.
Now Grosse wonders, like at least hundreds of others in Bucks and Montgomery Counties: Have we been poisoned?
For decades, Navy personnel used the firefighting foam at hundreds of bases. Now they know that it contained chemicals linked to cancers, and that those chemicals flowed through the groundwater, into wells, and out of the faucets of thousands of residents in Southeastern Pennsylvania.
Two former bases just north of Philadelphia have become the first Navy sites linked to drinking water tainted by these chemicals. As the Department of Defense investigates others across the country, what happens here could help shape the response nationwide.
Since 2014, nearly half of public drinking wells and scores of private wells in Horsham, Warminster, and Warrington have been shut down because of contamination. Some homeowners may have to use bottled water for up to a year; others have switched to bottled by choice.
Public awareness and alarm spiked last month when federal regulators issued new and stricter water quality standards that called into question drinking water that had previously been deemed safe.
Lawmakers now say the federal government should arrange blood screenings for nearly 70,000 residents. The Navy alone has already spent $19 million on its investigation and cleanup, which could take 20 years or longer. The Air Force, also involved, has dedicated $8.3 million so far.
Officials say the public wells still operating in and around the former stations in Warminster and Willow Grove meet today's safety standards.
But no one can tell residents how much toxic water they may have gulped down in the decades before the issue came to light - or if today's definition of safe may change again.
"I drank it for 25 years," said Grosse, 51, a mother of two who now lives in Lansdale, about 15 miles from her childhood home. "How long is it going to take to get out of my body?"
An uncertain risk
Growing up, summer nights for Grosse often meant running around with neighborhood children or playing in a creek until her mother rang a cowbell to call them home.
The Grosse family lived next to the former Naval Air Warfare Center in Warminster, a once-thriving 800-acre installation that closed in 1996 amid a wave of military cutbacks. It has since been redeveloped with a park, houses, and businesses.
A few miles away in Horsham, the former Naval Air Station Joint Reserve Base Willow Grove has sat nearly lifeless since 2011, awaiting its own redevelopment. The water contamination there has stalled a nearly $1 billion project to turn the 860-acre site into a community hub with houses, a school, and a retirement community.
The bases once teemed with thousands of pilots, personnel, and civilian employees, boosting area businesses and providing impromptu air shows as planes roared in the skies.
Both also housed large tanks filled with the chemicals to make the firefighting foam.
Hangar 175 at Willow Grove once sheltered four planes at a time but now sits vacant and ghostly. Inside, bright red cannons ring the perimeter, each connected to pipes that pumped the foam to the hangar.
The substance, like others used on site, included chemicals called perfluorinated compounds (PFCs), including PFOA and PFOS. PFCs were used for decades not just in the foams, but in non-stick cookware, clothing, furniture fabric, packaging, and carpeting.
The EPA said it began looking into the chemicals in 2000. Since then, more dangers of PFCs have come to light, largely out of a lawsuit against DuPont, which used them in its products.
By 2009, federal environmental regulators had set a "safe" limit of PFCs for drinking water.
Still, most Americans had no clue.
"It should have been on people's radar for testing drinking water long before this," said Richard Clapp, a professor emeritus at the Boston University School of Public Health who served as an expert witness for lawsuits against DuPont. "If it gets into the ground and rainwater brings it into the water table, it's going to be there."
The major PFOA manufacturers agreed under an EPA program to phase it out by 2015. But the chemicals had already reached water and bloodstreams.
At Willow Grove, the foam was used as recently as 2010. Some contamination occurred when fire suppression systems went off, releasing the foam. Navy reports describe hundreds of gallons going into sewage drains in some of these instances.
The Navy first understood the possible contamination risk from the foam in 2011 but"generally thought it was probably OK," said Gregory C. Preston, a Base Closure and Realignment Commission program director for this region. As it has done with other hazardous chemicals, he said, the Navy planned to examine the potential impact.
Only later did officials realize the compounds spread through groundwater "a lot more quickly" than expected, he said.
Scientists say the chemicals would have been seeping into the water supply for decades - for as long as the foams were in use, said Charles Haas, a Drexel University environmental engineering professor.
Navy tests detected PFOA and PFOS in groundwater at Willow Grove and Warminster in 2011, 2012, and 2013.
After the first Warminster sample, state and federal environmental regulators said "no follow-up action" was needed. The bases were already closed.
It was not until state officials separately saw signs of the chemicals in the public supply, in 2014, that three wells in Warminster were shut down. Later that year, wells in Horsham and Warrington were also shut down.
The EPA began sampling private wells, going door-to-door, and mailing fact sheets.
Tom Quinn and his wife got such a notice in 2014. They were unsettled but kept drinking the water. Now, despite being hooked up to a public well that officials say is safe, the Warminster family of four is using bottled water.
Quinn recalled the mixed messages he heard from one official.
"It's like, 'Everything's fine, everything's fine, everything's fine,' " he said. But then, about using the water for baby formula, he said they were told: "No - just in case."
Last month, the EPA released stricter water-quality guidelines based on studies that linked the chemicals and health problems including testicular and kidney cancers, liver damage, thyroid disease, and high cholesterol.
Sixteen of 36 public wells, serving an area with nearly 83,000 residents, have tested above the acceptable limit and been shut off, according to municipal data.
In the three townships, one-third of 342 homes with private wells have tested positive for unacceptable contamination. The EPA has identified about an additional 120 private wells for testing, but is awaiting residents' permission. The agency concedes there could be even more, but there is no complete database of private wells.
The Navy and the Air Force - which now operates an Air National Guard station on a small piece of the former Willow Grove base - will pay to switch households on tainted private wells to the public supply.
That could take up to a year.
Martin and Mary Kate Bockhorn have relied on private well water since moving to their Horsham home in 2009.
Two years ago, federal regulators had tested their well and told the couple the water was safe.
But last month, the Bockhorns got another call from their EPA contractor. The contamination threshold had changed, he told them, "and your well's been above it the entire time."
Now, they have 20 cases of bottled water delivered every two weeks.
Social media have helped connect dozens of people who lived or worked in the affected areas. Many share stories of cancer.
"Everyone that has any kind of ailment thinks it's from this water," said Jim McCusker, who moved to Warrington 10 years ago. "It's hysteria."
It is difficult to definitively link cancer in a person to a specific chemical. But ties between some cancers and the perfluorinated compounds, along with what residents view as unusually high reports of cancer in their neighborhoods, have spooked locals.
The Pennsylvania Department of Health and federal agencies are analyzing cancer data for the area; results are expected this summer.
Beth Blumenthal of Horsham was found to have uterine cancer in 2008. Her husband had colon cancer two years earlier, and they knew two neighbors with breast cancer. She said she does not necessarily believe the naval air station caused their illnesses, but hearing about the water contamination made her pause.
"I just thought it's strange," she said. "I didn't think about it until it started coming out, the cancer-causing agents."
Along with worries, frustration has spread swiftly.
Hundreds attended two open house information sessions in Horsham last month, but many left disappointed.
Residents waited in throngs to speak with officials from several agencies set up at separate tables. Some hoping for a presentation to the crowd said they did not get enough answers from one-on-one conversations.
Preston, coordinating Navy response, said he understands frustration. "We'll have as many hearings and as many sessions as we need to," he said.
State Rep. Todd Stephens (R., Montgomery) lives in Horsham. His family now drinks only bottled water. He started pressing for state action earlier this year after hearing from constituents.
"There's a false sense of security, I think, that many residents feel," Stephens said. "And I was guilty of this too, for a period of time. You feel like, OK, the EPA is handling it. So they would never let water that would be harmful come out of our faucets, right?"
Several lawmakers have asked the Navy to fund blood tests for nearly 70,000 residents of Horsham, Warminster, and Warrington. To test only half would cost about $7 million, Gov. Wolf's office said. A congressional subcommittee said Wednesday it sees Pennsylvania as a model and will work to fund health screenings.
As monitoring continues, the Defense Department has also begun groundwater testing and treatment at more than 660 other sites.
Three Philadelphia-area members of Congress whose districts touch the bases - Republicans Patrick Meehan and Mike Fitzpatrick and Democrat Brendan Boyle - have pressed the Navy for information. Boyle has called for a congressional hearing.
Some residents are considering legal action. On Tuesday, attorneys for a Warrington family said they had filed a notice of intent to sue the Navy and federal government. Another firm began this month investigating the issue on behalf of residents.
Officials involved in the cleanup, meanwhile, call it a coordinated effort.
The Navy and the Air Force have contracted with water authorities and are paying for cleanup, including private well transfers and filtration systems for offline wells.
The Navy has installed 32 more monitoring wells at Willow Grove in an effort to determine the extent of how far the contamination has spread. It also is working on a long-term plan to contain the chemicals and treat groundwater.
The goal is to make sure every well stays below the EPA threshold, which means chemicals are present but deemed safe to drink - unless guidelines change again.
Some residents are not waiting for the government to act.
Hope Grosse is attempting a health survey of as many current and former residents as she can find. She, herself, was diagnosed with melanoma at 26.
As she stood last week in the backyard of her childhood home, an idyllic place surrounded by shady oaks, kids played at the playground down the street where the base once stood and a runway still remains.
"There's a lot of whys I have, a lot of questions," she said. "My brain just gets blown up the more I think about it."
Correction: A previous version of this story misspelled the last name of Martin and Mary Kate Bockhorn.