LORI CERVERA HAD ALWAYS been an active person. She liked camping, playing outdoors with her kids, and practically lived in her running shoes. She didn’t have much patience for illness. So when she developed a dull ache on her right side in May 2014, Cervera took a few Tylenol and did her best to ignore it. But after a few days in which the pain grew sharper and more intense, she went to the hospital, where a CT scan revealed a mass. To her complete surprise, Cervera, a mother of four and grandmother of two who was 46 at the time, was diagnosed with stage 2 kidney cancer. That July she underwent surgery to remove both the tumor and almost half her right kidney.

Cervera returned to her home in Warrington, Pennsylvania, relieved to be alive but also perplexed. She had no family history of kidney cancer, and the diagnosis felt like it came out of left field. So with 22 staples still in her belly and a drainage tube coming out of her wound, Cervera propped herself up in bed and took to Google, intent on learning more about what might have caused her illness.

Her research quickly led her to a recent report on PFOA, or perfluorooctanoic acid, also known as C8, a chemical that for six decades was used by DuPont in the production of Teflon and other products. Research on people in West Virginia and Ohio who had consumed water contaminated by leaks from a nearby DuPont factory showed probable links between the chemical and six diseases, including kidney cancer.

Cervera soon discovered that the very same chemical, as well as a related one, PFOS, had been found in drinking water in her area. Both were part of a larger class known as perfluorinated chemicals, or PFCs, “emerging contaminants” that were still being studied — and had yet to be regulated. And, according to public notices from the local water and sewer authorities, both had come from foam that was used to put out airplane fires and train soldiers at two nearby military bases — the Naval Air Warfare Center in Warminster and a former naval air station at Willow Grove, now owned by the Pennsylvania Air National Guard.

Cervera knew the bases well. One of her daughters works across the street from the Naval Air Warfare Center, which everyone calls Johnsville. Willow Grove is only about a mile south of her house; she drives by it practically every day. The Wawa convenience store where she buys milk and gas is directly across the street from Willow Grove, which the Navy shut down in 2011. It wasn’t hard to imagine how water from that former base would make its way to her home. The road that runs between the two parallels a creek that floods practically every time it rains.

When they moved 25 miles north to Warrington from Philadelphia in 2000, the Cerveras had found the well at their new home charming. Now, after reading about the contamination, she regarded it with suspicion. Had the water she drank and used to make coffee, brush her teeth, fill kiddie pools, and mix infant formula for her grandchildren over the years contained chemicals from the military bases?

In August 2014, she decided to find out and requested a free test of the well water, which the local EPA office was offering to families living close to the bases. Three months later, an agency staffer rang her bell to hand-deliver the results: Though the chemicals were present in their well, they weren’t at levels of concern, he assured her. “We were so relieved,” said Cervera, who went on drinking and cooking with the water.

However, EPA monitoring done around the time of Cervera’s surgery showed that the Warminster municipal water authority, which provides water to the township adjacent to Warrington, had the third-highest level of PFOS of all public drinking water systems tested in the entire country — 1.09 parts per billion — as well as a very high rate of PFOA, .349 ppb. The Warminster water authority stopped using two of its public wells last year because of the contamination. Warrington Township, where the Cerveras lived, found PFCs at elevated levels in three of its public supply wells and also shut them down. The chemicals had spread into some private wells, too. By June 2015, 45 had been identified with either a PFOA or PFOS level above the safety threshold set by the EPA. The chemicals were also present at lower levels in more than 100 other wells.

In late January 2015, a second test of the Cerveras’ well showed higher levels of contamination, but they were given no indication that they should stop drinking the water. Then, in August, a few weeks after a third test of their well water, a worker from the lab that processed their sample called to tell them to stop drinking it immediately. A few days later, several 5-gallon jugs of water arrived at their home. Cervera noticed the same plastic jugs began to appear outside many of her neighbors’ homes as well.

A small sea of fire retardant foam was unintentionally released in an aircraft hangar, temporarily covering a small portion of the flight line at Travis AFB, Calif., Sept. 24, 2013. The non-hazardous foam is similar to dish soap and eventually dissolved into liquid, which was helped by high winds. The 60th Air Mobility Wing firefighters helped control the dispersion by using powerful fans and covering drains. No people or aircraft were harmed in the incident. (U.S. Air Force photo/Ken Wright/Released)

A small sea of fire retardant foam was unintentionally released in an aircraft hangar, temporarily covering a small portion of the flight line at Travis Air Force Base in California, Sept. 24, 2013.

Photo: U.S. Air Force

IN MAY 2014 when Cervera was first noticing the pains in her side, Andrea Amico read in her local paper that PFCs had been found in the water on the former Pease Air Force Base near her home in Portsmouth, New Hampshire. The level of PFOS in one of the wells serving Pease was 12 times a provisional safety level set by the EPA — so high, in fact, that the city promptly decided to shut it down.

Pease, which was a Strategic Air Command facility and Air Force base until 1991, is now home to a golf course, a commercial airport, and more than 250 businesses employing some 9,500 workers. Amico works as an occupational therapist for a hospital that’s based there, and her husband, a graphic artist, worked at Pease for more than eight years. But when she heard about the contamination, Amico’s thoughts immediately turned to her son and daughter, ages 2 and 4, who have attended Great Bay Kids’ Company, one of two childcare centers at Pease, since they were 12 weeks old.

“I was like, oh my God, my children are in daycare there,” she said. “What are these chemicals?”

The answers she has received over the past several months have often contradicted one another, sending Amico on a journey through medical journals, doctors’ offices, and public forums. What is indisputable is that PFOA and PFOS are part of a group of man-made chemicals that have been tied to a range of health effects, from obesity in children to reproductive problems and cancers. Used to make Teflon, stain- and water-resistant coatings, cosmetics, and hundreds of other products, PFCs persist in the environment and are easily absorbed by the human body. Both PFOS and PFOA, the best studied of these chemicals, have been shown to be “endocrine disruptors,” tiny amounts of which can interfere with the hormonal system.

What was less clear to Amico was how being exposed to these contaminants would affect her family. PFCs, she knew, can cross the placenta, showing up in cord blood and newborns. They also accumulate in breast milk. And several studies have shown children to be particularly vulnerable to their effects.

Yet some state officials she encountered at community meetings seemed more interested in calming her down than giving her an honest picture of the dangers of PFCs. “They weren’t giving us the whole story,” said Amico. “There’s this apprehension that we’re going to freak out.”

Nor were the local authorities of much help when it came to finding out how much of the chemicals her family members had in their bodies. Right after the contamination was discovered, Rick Cricenti, director of the Emergency Services Unit at the New Hampshire Department of Health and Human Services, promised to help Amico get blood tests, she said. But eventually he stopped replying to her emails and returning her calls, and Amico spent more than seven months trying to find anyone to help her determine the level of PFCs in her family’s blood.

Jet fuel is made to burn. When airplanes crash, the reserve of the hydrocarbon liquid can produce a massive, violent fireball. Water, which doesn’t mix with the fuel, does little to extinguish these explosive fires, often just boiling off or sinking ineffectually under the fuel itself. So, about 50 years ago, the Minnesota-based chemical manufacturer 3M, in conjunction with the Navy, developed a product that would help extinguish such fires.

The sudsy liquid, dubbed “Aqueous Film-Forming Foam,” or AFFF, put out hydrocarbon fires more quickly and effectively than ever before by smothering them. Since it was developed, the military has been using huge quantities of the foam, which has been heralded for saving firefighters’ lives. Unfortunately, 3M’s miracle product also contained PFOS. And the other official formulation of the foam purchased by the Department of Defense contains “telomers,” compounds that can break down into PFOA and other PFCs. In addition to being linked to health problems, PFOA and PFOS stay in the human body for years and, unless they are removed, persist in the environment indefinitely.

The extent of contamination would no doubt be far less if the military had just used the foam to put out crash fires, which are fairly rare. Between 1979 and 2000, for instance, there were only four plane crashes near Willow Grove. But the foam is also used to teach soldiers to put out fires, and those training exercises are common. A typical exercise, which has been conducted by various branches of the military many thousands of times since the 1960s, involves flooding a fire pit with flammable liquids, lighting them on fire, and then putting out the flames with between 75 and 100 liters of firefighting foam. For decades, no one thought to construct barriers at these sites to contain the foam, which sank down through the earth into the water table.

CONTAMINATION FROM THIS frequent dousing with PFC-laced foam is a far bigger problem than either Amico or Cervera imagined. Water testing done in or near military bases, which isn’t yet complete, has already shown that the chemicals spread into public drinking water systems around Willow Grove, Pease, and a third base — Eielson, in Alaska. PFCs have also been detected in the ground water at many more bases, including the Air National Guard base in Delaware; the Grissom Air Reserve Base in Indiana; and the Naval Air Station in Fallon, Nevada. Indeed, according to a 2013 presentation by the Air Force, PFCs were found at every Air Force base that had been tested, which so far includes Randolph in Texas; Robins in Georgia; Beale and McClellan in California; Eglin in Florida; Ellsworth in South Dakota; and F.E. Warren in Wyoming.

Data on PFC drinking water contamination are collected under the Unregulated Contaminant Monitoring Rule (UCMR) for suspected contaminants for which the EPA has not established health-based standards under the Safe Drinking Water Act. The drinking water data in this map were taken from the October 2015 UCMR 3 data summary. In addition, the map shows 664 fire- or crash-training sites, identified by the Department of Defense, where a PFC-laced fire suppressant known as Aqueous Film-Forming Foam was used, often for decades. Not all of these sites have been tested for PFCs, but it is likely that all of them are contaminated. Data visualization: Moiz Syed. Sources: EPA and Department of Defense.

In some of these places, huge amounts of chemicals from the foam have been found in soil and water. At Tyndall Air Force Base in Florida, for instance, one of the telomers that can decay into a chemical similar to PFOA was found at 14,600 ppb. Near the Naval Air Station in Fallon, Nevada, where fire-training exercises were conducted for more than 30 years, PFOA has been recorded in the groundwater at levels as high as 6,720 ppb. And, at the former Wurtsmith Air Force Base in Michigan, where crash trainings also took place for more than three decades, one plume of groundwater had concentrations of total PFCs between 100,000 and 250,000 ppb.

It’s clear that the full extent of the contamination will be much bigger still. As of 2014, there were 664 current or former military fire- or crash-training sites in the U.S., according to a statement from the Office of the Secretary of Defense. The Air Force and Navy have the largest number of these spots. Although the DOD has said it’s too early in the cleanup process to know how many of these sites have been contaminated with PFCs, it is likely that all of them have, said Jennifer Field, a professor of environmental and molecular toxicology at Oregon State. Field has been studying the environmental fate of the chemicals used in firefighting foam and has yet to see an area where the foam was used in which PFCs have not been detected.

“We’re batting 100 on the bases where they’ve had fire-training sites,” Field told me. “Even one crash site can leave a fingerprint.” No one yet knows the full extent of the emerging environmental contamination caused by the firefighting foam. But according to Field, “It’s going to be big.”

The U.S. military, which has been using the foam in fire-training exercises since the 1960s, is the biggest user — and polluter — by far. But commercial airports, airplane hangars, oil refineries, fire departments, petrochemical transfer and production sites, and heliports have also used firefighting foam containing PFCs for decades, which likely pushes the total number of contaminated sites into the thousands, according to Thomas Bruton, a PhD candidate in environmental engineering at Berkeley who is studying PFC contamination.

There’s little doubt that, together, widespread use of firefighting foam has contributed to the exposure of huge numbers of people to PFCs. EPA monitoring begun recently found PFOS in water systems serving almost 10 million Americans, most of whom have no idea they’re drinking it. The number of potentially exposed people climbs to more than 14 million when the other five PFCs now being monitored by the EPA are included. And those six chemicals are only the tip of the iceberg; more than 2,000 PFCs have already been identified on the global market, and scientists expect that number to climb to 4,000.

Even as the Air Force, Navy, and the Department of Defense struggle to clean up this massive environmental mess, the military continues to use PFC-containing firefighting foam for both training purposes and emergencies. The military has the largest stockpile of PFOS-containing firefighting foam in the United States, with around a million gallons, according to a 2011 estimate by the Fire Fighting Foam Coalition, an industry group. While the EU and Canada have banned the use of stockpiled foam containing PFOS, the U.S. has no restrictions on its use.

In fact, the current military specifications for firefighting foam require that the product contain PFCs. In response to a list of questions provided by The Intercept, a military spokesperson wrote: “Until non-PFC formulations are certified, DOD is implementing measures to prevent uncontrolled releases of firefighting foams during maintenance and firefighting training exercises. Additionally, DOD will be removing stocks of PFOS-based foam where practical.” While the military can still use the stockpiled foam, according to the DOD response, “Non-PFOS based foams, which do contain shorter-chain PFCs, will continue to be the main product used for firefighting until non-PFC formulations can be tested and certified to meet the military performance specifications.”

These products using “shorter-chain” PFCs, which manufacturers have been shifting to in recent years, consist mostly of molecules with either four- or six-carbon bases, as opposed to eight, like PFOS and PFOA. Industry has claimed that the new compounds are safer, because the shorter-chain molecules have a shorter half-life. But since long-chain chemicals persist indefinitely, the practical difference may not amount to much. To date, little research has been completed about the health effects of these chemicals. Experts disagree about their potential to cause harm, but they are suspected to persist in the environment and to accumulate in the human body.

In recent years, biologists have begun to trace the path of chemicals from firefighting foam through the environment, and PFCs from the foam have been shown to accumulate in earthworms. At levels between 10 and 120 ppb, PFOS can damage the worms’ DNA. Fish swimming near the Wurtsmith base had internal PFOS levels as high as 9,580 ppb. Birds that eat these fish have PFCs in them, too.

The chemicals are clearly entering humans’ bodies as well. Before the 1940s, when the first PFCs were developed, no one had them in their blood. Now, it’s virtually impossible to find anyone who doesn’t have at least trace amounts of these man-made substances in their bodies, most of which likely come from exposure to the chemicals in consumer products.

The PFCs from firefighting foam can add substantially to this burden, as Andrea Amico now knows. After several months of public meetings, letter writing, and phone calls, she finally managed to get free testing approved not just for her family but also for anyone who drank the water on Pease. Rick Cricenti, the New Hampshire official who stopped responding to Amico’s communications, referred me to a spokesperson for the New Hampshire Department of Health and Human Services, who did not dispute her version of events but said, “I feel good about the department’s response ultimately to this contamination.” Eventually, that response included working with the CDC to offer blood testing to anyone who was affected. So far, 1,600 people have had their blood tested for the presence of nine PFCs. The first of the results, which were released in August and September, showed that the average level of PFOS in children who were exposed to water from Pease was more than double the rate measured in a comparison group of children. Levels of another PFC called PFHxS were particularly high — more than triple the national average among adults and five times higher than a comparison group among children.

Amico’s daughter, who was just 4 when she had her blood tested, had a PFOS level that was more than four times that of a group of children from elsewhere in the country; her PFHxS level was more than 12 times higher.

Aqueous Film Forming Foam, or AFFF, fills Hangar 211 Dec. 21, 2012, at Mountain Home Air Force Base, Idaho. Personnel from the 366th Civil Engineer Squadron performed the test to ensure aircraft maintainers who work inside this hangar will have a safe place to perform their operations – in the event of a fire the system will protect the Airmen and equipment. (U.S. Air Force photo/Senior Airman Heather Hayward/Released)

Aqueous Film-Forming Foam, or AFFF, fills Hangar 211 at Mountain Home Air Force Base, Idaho, Dec. 21, 2012.

Photo: U.S. Air Force

IN 2006, THE EPA helped broker a deal under which the eight companies in the U.S. that were making or using PFOS and PFOA would stop doing so. As of this year the companies say that they have. But the federal agency dedicated to protecting human health and the environment has yet to set a safe level of lifetime exposure to the chemicals.

As The Intercept reported in August, Robert Bilott, an attorney representing people living in West Virginia and Ohio near a DuPont plant, first asked the EPA to regulate PFOA in 2001 under the Toxic Substances Control Act, “on the grounds that it ‘may be hazardous to human health and the environment.’” Bilott based his plea on decades of research on PFOS and PFOA he had uncovered through his legal work. In one of the many studies he unearthed, which was reported by 3M scientists in 2001, two of six male monkeys exposed to PFOS died. The chemical also caused monkeys to lose weight, increased the weight of their livers, and interfered with various hormones.

Still, the EPA didn’t address the question of how much PFOA or PFOS might be safe until 2009, after the agency discovered that sludge containing high levels of both chemicals had made its way from a wastewater treatment facility in Decatur, Alabama, to nearby fields. For 12 years, it turned out, that contaminated sludge had been spread across 5,000 acres of local grazing land. The fear was that the chemicals would make their way into animals and humans in the rural area. And, in fact, they did. But even so, the EPA didn’t enact binding regulation, which could have been used to force the companies responsible for the chemicals’ presence in water, including 3M, to clean up the contamination.

Instead, the agency came up with a temporary, unenforceable solution to the PFC problem. The Provisional Health Advisory on PFOS and PFOA that the EPA released in 2009 referred to the industry’s monkey research and other evidence of disturbing health effects of PFCs on animals when it calculated the maximum levels of these chemicals that humans should be exposed to through drinking water. For PFOS it was 0.2 ppb; for PFOA, 0.4 ppb. But these levels fall short of enforceable regulations.

And both are for “short-term exposure,” which according to the EPA means they are supposed to apply to periods of exposure that last from “weeks to months.” Yet Andrea Amico’s oldest child was exposed for years — indeed, for most of her life. In all likelihood, Lori Cervera and her family drank contaminated water for as long as 15 years. And many others living near fire-training sites may have been exposed to the chemicals for far longer, since the military has been using the foam for close to 50 years.

Although the EPA has repeatedly said it would update these numbers, it hasn’t done so since 2009. In a written response to questions from The Intercept, Cathy Milbourne, an EPA spokesperson, said the agency expects to finalize health advisories for PFOA and PFOS “this winter.” Once published, those numbers will supersede the provisional health advisories from 2009.

In the meantime, the military continues to use the provisional safety levels to guide its response to contamination from AFFF. One of the agency’s Q&A sheets, for instance, assures people living near Willow Grove that these levels “are intended to ensure protection of public health, with a margin of safety built-in.” Those in charge of the cleanup there use the numbers to determine who receives bottled water and which homes now reliant on contaminated private wells will be connected to public water systems. And residents whose wells contain even slightly less than this amount and who have been drinking the chemicals for years may be reassured, as Cervera was, that their water is safe to drink.

Water and foam flow from a fire hose after an aircraft fire training exercise, Aug. 27. The fire department uses AFFF foam concentrate to smother fires.

Water and foam flow from a fire hose after an aircraft fire-training exercise, Aug. 27, 2011.

Photo: U.S. Department of Defense

SINCE THE EPA SET these provisional levels, evidence has emerged suggesting that guidelines for safe levels of PFC exposure over the long term should be much lower. In 2009, the same year that the EPA set its short-term level for PFOA at .4 ppb, a group of water experts appointed by New Jersey’s Department of Environmental Protection calculated what they thought should be a safe lifetime limit for drinking water: .04 ppb, one-tenth the EPA’s provisional level. And since then, much evidence has emerged showing that the long-term level should be lower still.

In 2012, data gathered from plaintiffs in a class-action suit Bilott and others filed against DuPont found that exposure to PFOA was likely linked to kidney cancer, testicular cancer, thyroid diseases, ulcerative colitis, high cholesterol, and preeclampsia. The minimum level of contamination in water districts represented in the suit was low — just .05 ppb, a small fraction of the level now being used to guide cleanup — and more recent research suggests maximum levels for drinking water should be even lower than that.

For years, industry did the vast majority of research on PFCs, most of which was never made public. “We didn’t pay attention to the PFCs because it looked like there was nothing,” said Philippe Grandjean, a physician and environmental health researcher at the Harvard T.H. Chan School of Public Health. But in 2000, after conducting a study of the health effects of PFOA on monkeys, 3M announced that it would phase out production of both PFOS and PFOA. “It was when industry said ‘oops,’ that’s when the academics got started,” said Grandjean.

Grandjean himself became interested in PFCs after he noticed a 2008 study in which researchers looked at how the chemicals affected mice. “Animal toxicologists got to the immune system and — bing! — they found these very strong effects.” Grandjean wondered whether the chemicals might have similar effects in children and devised a way to find out: He looked at the blood from group of young children before and after they were vaccinated for tetanus and diphtheria. His findings, which were published in the peer-reviewed Journal of the American Medical Association in 2012, were striking: After being vaccinated, 7-year-olds who had very slightly elevated levels of PFCs in their blood tended to have lower levels of antibodies to those diseases. For each doubling of exposure to the chemicals, the risk that the vaccine didn’t take increased twofold to fourfold.

“I fell off my chair when we got our first results,” said Grandjean, who believes the study has broad implications for overall immune function, which affects the development of allergies, autoimmune diseases, cancers, and a huge range of other illnesses. Indeed, a separate study, published in 2013, bears out his hunch. This one mapped certain illnesses to exposure to very low levels of certain PFCs in Norwegian children. Those who had higher levels of PFOA and another perfluorinated chemical, PFNA, got more colds. And those who had higher levels of PFOA and PFHxS, the chemical found at elevated levels in many of the people near Pease, were more likely to get stomach infections.

Based on his findings — which were corroborated by other research showing an association of very small amounts of PFCs in the blood of pregnant women in Demark with increased risk of miscarriage — Grandjean came up with a maximum level of the chemicals that would be safe to ingest that was much lower than the provisional level set in 2009. “You need to get down to something like several hundredfold less than what EPA originally set,” said Grandjean, who has suggested a safe level should be set below .001 ppb instead of 0.2 or 0.4.

Though it came close, the contamination detected in Lori Cervera’s well never exceeded the EPA’s guidelines for short-term exposure. After years of exposure, though, even tiny amounts of the chemicals can be harmful, according to Grandjean. Because PFCs accumulate in the body — it takes five years for people to get rid of just half of PFOS in their bodies, for instance — for people who have been chronically exposed, like Cervera, “any additional exposure should be prevented,” said Grandjean.

It’s never easy to find and clean up tiny molecules that have been scattered through vast amounts of water and soil.

And the effort to rid the environment of PFCs from firefighting foam promises to be especially messy and difficult. Not only have these chemicals been spread across the entire country, they’re often mixed in with other contaminants, including jet fuel, benzene, and other byproducts of combustion. This is certainly the case at Eielson, Pease, and Willow Grove, all of which were Superfund sites well before they were known sites of PFC contamination from firefighting foam.

So far, the best method for cleaning up PFCs requires putting contaminated water through an “activated” carbon filter, and then burning the chemicals that have been filtered out. The process is expensive, as is the pumping of the water from the ground to a place where it can be treated.

Indeed, in July, the Navy agreed to pay $8.8 million to treat the public drinking water wells of the Horsham Water and Sewer Authority near the Cerveras’ home and almost $4 million to clean the water at the Warminster Municipal Authority in the next town. And those costs are only for cleaning wells that have PFCs above the provisional advisory levels.

Because PFCs are unregulated, the law doesn’t require their cleanup — and the costs of getting them out of the environment aren’t covered by the Superfund program. Nevertheless, the Air Force has decided it will address the contamination on a case-by-case basis, reviewing and addressing requests for action on PFCs when “direct human exposure, and/or off-site migration is identified.”

The consequences of not adequately cleaning the PFCs loom large. At Willow Grove, for example, plans are already underway to develop housing, a school, and a retirement community.

An Aviation Boatswains Mate (Handling) walks through aqueous film forming foam after a test of the sprinkler systems aboard the flight deck of the aircraft carrier USS Ronald Reagan. The testing of fire safety equipment is just one of many evolutions performed to ensure Ronald Reagan's sea readiness during a planned incremental maintenance period. Ronald Reagan is performing sea trials off of the California coast. (Photo by: Seaman Benjamin C. Jernigan)

A man walks through Aqueous Film-Forming Foam after a test of the sprinkler systems aboard the flight deck of the aircraft carrier USS Ronald Reagan, May 19, 2010.

Photo: U.S. Navy

IN OCTOBER, A JURY found DuPont liable for $1.6 million in damages to a woman who had developed kidney cancer after drinking PFOA-contaminated water near one of the company’s plants. Though she developed the same disease after similar exposures, at this point, Lori Cervera is unlikely to have such success in the courts.

In the DuPont cases, the second of which will be tried in March, there is ample evidence the company was responsible for putting the chemical into local drinking water. And, according to the terms of the class-action suit from which the case stemmed, the jury had to accept that PFOA can cause kidney cancer.

If Cervera were to sue, her lawyers would have to sort through a tangle of potentially responsible parties. Over time, the bases near her have been home to several branches of the military, including the Navy, the Air Force, the Air National Guard, and the Army Reserve. Suing any of them is notoriously difficult. And then there is the challenge of sorting out which of several companies made the particular foam in question. Though 3M was the sole supplier of firefighting foam to the U.S. military until 1982 and made about three-quarters of the military’s entire stockpile, six other manufacturers, including Ansul, Chemguard, National Foam, and Buckeye Fire, have also sold firefighting foam to the military. And they bought some of the chemicals used in the foam from other companies.

National Foam, Ansul, and Chemguard declined to comment for this story. Buckeye Fire did not respond to repeated requests for comment. 3M provided the following statement:

“3M’s AFFF products were all sold with material safety data sheets, or MSDSs, that advised how to handle and dispose of the product in a safe and effective manner,” Donna Fleming Runyon, spokesperson for 3M, says. “When used properly, we believe AFFF was safe and effective. In fact, the products are widely credited with benefiting the military and civilian firefighters around the world. They are known in many cases to have saved lives.”

“We believe that PFCs, such as PFOS and PFOA, do not present health risks at the levels they are typically found in the environment or in human blood,” says Carol A. Ley, MD, vice president and corporate medical director, 3M Medical Department. “In more than 30 years of medical surveillance, we have observed no adverse health effects in our employees resulting from their exposure to PFCs such as PFOS and PFOA,” says Ley. “This is important since the level of exposure in the general population is hundreds, if not thousands, of times lower than that of production employees who worked directly with these materials.”

Still, Cervera was considering her legal options — and, for months, waiting for calls back from the Centers for Disease Control, the EPA, and the local base closure office to get more information about her exposure over the years. But at press time, a routine blood test had heightened her doctors’ suspicions that her cancer had returned — and banished, for now, Cervera’s questions about why she got sick.

Back in New Hampshire, Amico is now part of a recently formed community advisory board at Pease that is working with the Agency for Toxic Substances and Disease Registry to design a health study to see how the PFCs in drinking water might have affected the health of people who drank water there. It will likely be years before any results emerge from this research.

The U.S. isn’t the only country contending with the environmental consequences of firefighting foam.

PFC contamination from the foam has recently been discovered in Europe, Japan, and Australia, where TV coverage likened the widespread contamination to “Agent Orange, all over again.”

Perhaps the most instructive response to the problem has been in Ronneby, a small town on the southern coast of Sweden. In December 2013, the level of PFOS in drinking water there was found to be elevated. As in the U.S., the Swedish contamination was tied to firefighting foam used by Sweden’s air force. But unlike in the U.S., the response in Ronneby was thorough, swift, and very open.

As soon as the problem was discovered, it was widely reported to the public and clean water was distributed. Blood sampling of exposed residents got underway by February and initial results from those tests were reported in March. Within months, a Swedish university received an emergency research grant to study the health effects in the population and the government mobilized a network of national agencies to work on the issue.

As in the U.S., plenty of questions remain about the PFCs in Ronneby. Epidemiological studies of the health of the local population, while already funded, won’t get underway until 2016, according to Kristina Jakobsson, a professor of occupational and environmental medicine at Gothenburg University. But the process is clearly already a governmental priority — or as Jakobsson put it simply, “an act of responsibility.”

Research: Danielle Mackey and John Thomason