News that the Environmental Protection Agency pressured the federal Agency for Toxic Substances and Disease Registry to suppress a study showing PFAS chemicals to be even more dangerous than previously thought drew outrage this spring. The EPA pressure delayed the study’s publication for several months, and a similar dynamic seems to have been in play this July in Michigan, where Robert Delaney, a state scientist who tried to raise alarms about the chemicals six years ago, was largely ignored. Delaney, who delivered a report to his superiors about high levels of the chemicals in fish and the dangers they presented to people, has been heralded as prophetic. And both delays are being lamented as missed opportunities for getting critical information to the public.

But the dangers presented by these industrial chemicals have been known for decades, not just a few months or years. A lawsuit filed by Minnesota against 3M, the company that first developed and sold PFOS and PFOA, the two best-known PFAS compounds, has revealed that the company knew that these chemicals were accumulating in people’s blood for more than 40 years. 3M researchers documented the chemicals in fish, just as the Michigan scientist did, but they did so back in the 1970s. That same decade, 3M scientists realized that the compounds they produced were toxic. The company even had evidence back then of the compounds’ effects on the immune system, studies of which are just now driving the lower levels put forward by the ATSDR, as well as several states and the European Union.

The suit, which the Minnesota attorney general filed in 2010, charges that 3M polluted groundwater with PFAS compounds and “knew or should have known” that these chemicals harm human health and the environment, and “result in injury, destruction, and loss of natural resources of the State.” The complaint argues that 3M “acted with a deliberate disregard for the high risk of injury to the citizens and wildlife of Minnesota.” 3M settled the suit for $850 million in February, and the Minnesota Attorney General’s Office released a large set of documents — including internal studies, memos, emails, and research reports — detailing what 3M knew about the chemicals’ harms.

Some of the documents had been under seal since 2005 as a result of a separate lawsuit over PFAS contamination in Minnesota. And the documents had been in the EPA’s possession for at least 18 years: In 2000, 3M gave the EPA hundreds of documents it had withheld from the agency, resulting in more than $1.5 million in penalties in 2006 for 244 violations of the Toxic Substances Control Act. Even so, for years the EPA did nothing. Even as a few government officials and company scientists understood the vast dangers they posed, PFAS were allowed to spread into groundwater and then drinking water, into people and their children, into animals, plants and the food system where they remain today.

Suppressing Damaging Data

As a staff epidemiologist at 3M, Geary Olsen has had a wealth of data at his fingertips. The company he’s worked for since at least 1998 makes more than 55,000 products and has more than 90,000 employees. Olsen had access to internal information about both and has been able to combine them to pursue the kinds of scientific questions most researchers can only dream of being able to ask and answer.

In one study, for instance, Olsen looked at blood tests of 3M employees at the company’s plants in Antwerp, Belgium, and Decatur, Alabama, both of which made PFOA and PFOS, among other products. By the late 1990s when Olsen was embarking on this research, these chemicals were known within the company to accumulate in humans and alter cholesterol levels in lab animals. Because the workers had undergone three separate rounds of blood tests, Olsen was able to trace the levels of the chemicals in workers’ blood over time. And by combining his results with various clinical measures the company had been tracking in its workers, he was able to see whether there was a relationship between the chemical and these health outcomes.

Olsen’s findings, written up in an draft report in October 2001, were clear. There was a positive association between the amount of PFOA in workers’ blood and their levels of cholesterol and triglycerides, states the report, on which Olsen is listed as the principal investigator. The report devoted more than 20 tables to triglycerides and cholesterol, detailing a relationship that later studies would confirm: PFOA increased people’s levels of triglycerides, which are a type of fat, and cholesterol, both of which can increase the chance of heart disease. The results were in keeping with rat evidence, as the report noted.

Yet less than two years later, when Olsen and the three co-authors on the report — all 3M employees — published an article based on the same research, it downplayed this key finding. Indeed, according to the study, which ran in the March 2003 issue of the Journal of Occupational and Environmental Medicine, “There were no substantial changes in hematological, lipid, hepatic, thyroid, or urinary parameters consistent with the known toxicological effects of PFOS or PFOA” — a statement that appears to contradict the authors’ earlier finding.

In the 19th paragraph of the 2003 article, the authors note that PFOA was “positively associated with cholesterol and triglycerides” and that “serum PFOS was positively associated with the natural log of serum cholesterol … and triglycerides,” but dismiss these effects as “minimal.” The article omits most of the information that was contained in the draft’s tables and clearly laid out the increase in cholesterol and triglycerides in exposed workers.

The minimizing of this bad news is just one of several instances in which 3M seems to have downplayed, spun, and tailored its own research to make these two PFAS chemicals and others it produced appear safer than they were, according to the documents made public by Minnesota’s attorney general.

In some cases, relatively reassuring findings about the chemicals made their way into the scientific literature, while other more concerning ones — like the 1993 observation that goats passed PFOS to their offspring through their milk, or the 1998 discovery that PFOS had made its way into eagles found in the wild, or the association between PFOA and lipids that Geary identified — did so only after many years. In several cases, 3M appears to have not pursued further research based on discoveries that suggested the chemicals posed harm. And the company also relied on several paid scientists, including John Giesy, now a professor at the University of Saskatchewan, who weighed in on the environmental impact of PFOA and PFOS without disclosing their funding from 3M.

In an email, a 3M spokesperson strenuously denied that the company tailored its research around PFAS, writing that “neither 3M nor Dr. Olsen has distorted or suppressed the scientific evidence regarding PFAS in any way.” The email also pointed out that the company eventually gave the EPA Olsen’s 2001 report, which at this point has “been publicly available for well over a decade.” While acknowledging that Olsen found an association between cholesterol levels and PFOA, the 3M spokesperson noted that the effect of PFOA he documented in some workers — increasing cholesterol levels — was inconsistent with those observed in rats, whose levels decreased after exposure to the chemical, and that “the science is complex and neither the study nor the larger body of scientific evidence on this issue establishes causation.”

In a separate email, the 3M spokesperson wrote that “the Minnesota Attorney General released a small set of documents that should not be taken out of context in an effort to distort the full record regarding 3M’s actions with respect to PFOA or PFOS. 3M acted reasonably and responsibly in connection with products containing PFAS, and stands behind its environmental stewardship record.”

Giesy did not respond to a request for comment, but the University of Saskatchewan provided a statement saying that “Prof. Giesy rejects the unproven claims, which were never tried or tested in court.” Giesy “encouraged the company to voluntarily cease production of the chemical,” the university’s statement goes on to say, also noting that it conducted an investigation, which determined that Giesy had not violated university policy. The statement also pointed out that Giesy has not worked for 3M since he began working at the University of Saskatchewan in 2006.

Paul Brandt-Rauf, editor of the Journal of Occupational and Environmental Medicine, declined to comment, citing pending letters to the editor in his journal.

Yet the documents released by the Minnesota Attorney General’s Office demonstrate that 3M’s communications strategy altered the scientific record on PFAS by prettifying the scientific picture of PFOA and PFOS over the more than four decades it produced them.

While 3M readily paid its fines, there was no undoing the delay in regulatory action that resulted from the previous decades of keeping its damning information secret. While the studies sat in 3M’s private files, PFAS chemicals from the company’s facilities were entering the water in Minnesota, Alabama, and elsewhere, and PFOS and PFOA were accumulating in the environment and in people, the vast majority of whom now have the chemicals in their blood.

The lag in getting scientific information to regulators in turn resulted in prolonged public exposure to the chemicals, as Philippe Grandjean argues in an editorial in the journal Environmental Health. A physician and environmental health scholar who has studied the immune effects of PFAS and provided expert testimony for Minnesota in the 3M case, Grandjean argues that regulators should learn from this massive misstep, and that substitutes for PFOS and PFOA “should be subjected to prior scrutiny before widespread usage.”

The Washington Works DuPont plant in Parkersburg, W.V., on Oct. 28, 2015.

Photo: Maddie McGarvey/ For The Washington Post via Getty Images

The Principled Path

The history of PFAS compounds has mostly revolved around DuPont. That giant company also knew for decades that PFOA was escaping its plant, leaching into nearby drinking water, accumulating in the blood of its workers, and harming animals tested in its own labs. Since 2004, DuPont has paid more than $1 billion in class-action litigation and several related suits filed by people living near its plant in Parkersburg, West Virginia — and faced massive public outrage over its actions.

To the extent that 3M has come up in coverage of the fast-growing PFAS story, it’s largely been as a footnote — and a foil. 3M was the company that invented PFOA and sold the toxic stuff to DuPont, whose corporate image was besmirched by the news of its deceptions around PFOA. DuPont has also faced a firestorm of protest over GenX, its similarly toxic replacement for PFOA.

As 3M executives have pointed out on numerous occasions, their company phased out PFOA six years before DuPont did. (DuPont never manufactured PFOS.) “3M has acted appropriately and on the principled path,” William A. Brewer III, a partner in a law firm representing 3M in perfluorinated chemical-related litigation, told me when I first wrote about Minnesota’s lawsuit in 2016. “They immediately reported it, investigated it, and frankly decided to exit the C8 chemistries in their entirety well more than a decade before anyone else who was a competitor.”

But the documents from the Minnesota suit upend the narrative of 3M as the good corporate citizen.

In 1948, 3M, or the Minnesota Mining and Manufacturing Company, as it was then called, acquired the patent for a process of creating compounds out of fluorine. Manhattan Project scientists — several of whom landed at 3M after the war — had already used fluorine to separate the uranium used for the atom bomb. Their new method bonded carbon to fluorine atoms, creating novel materials such as an extraordinarily stable fluid called PFOA. 3M executives believed that the substance might have commercial applications, though they didn’t at first know what those might be. In 1950, after two years of conferring with various companies, 3M landed a deal to sell PFOA to DuPont to make Teflon. After that, “we were in business,” a 3M executive later recalled.

3M would continue to sell PFOA to DuPont for more than four decades. Starting in the early 1950s, the company also made PFOS, a closely related compound that wound up in hundreds of products, including the company’s own Scotchgard fabric protector, which, by the end of the 1950s, was being applied to both upholstery and clothing; and firefighting foam that 3M provided exclusively to the U.S. military for decades. 3M went on to market some of these its fluorochemical products as “the solution for your problems.”

3M’s fluorochemicals helped the company expand into a behemoth worth more than $120 billion. But the story of 3M “is clearly not a story of molecules, compounds, good science or technology,” as the company’s own corporate history explained in 1991. “It is a story of people.” Indeed, while 3M was distinguished by both its industrial chemistry and occupational health, it was individuals who made the fateful choices about which lines of scientific inquiry to pursue — and which to share with the public.

A Medical Mystery

The first scientists to raise the alarm about the fluorine-based chemicals didn’t work for 3M. In August 1975, a University of Florida researcher named Warren Guy called the company to get help with a medical mystery his colleague, Donald Taves, had stumbled upon. Taves had detected a form of fluoride in his own blood that hadn’t been found in blood before. The fluorine didn’t break down and appeared to be part of a large and stable molecule. The discovery sparked the scientists to look for and find fluorinated compounds in other blood samples, as they described in a 1975 paper. Guy was calling 3M to ask whether Teflon and Scotchgard might be the source of the compounds.

“We plead ignorance,” one of 3M’s chemists, G. H. Crawford, recounted in a summary he wrote up after the call. But within a few months, staff scientists knew quite a bit about the fluorinated compound found in blood. They compared the unique spectrum of its own patented compound, PFOS, with that of the chemical identified by Taves and Guy and found that they matched, according to a timeline the company compiled in 1977.

During the phone call, Crawford also suggested that Guy check blood samples from “uncivilized areas, e.g. New Guinea” where Teflon and Scotchgard weren’t in use. Later testing of historical blood samples would show Crawford’s suspicion to be spot on. After their introduction into consumer products in the 1950s, the fluorinated compounds began to appear in blood samples from around the world going as far back as 1957.

Closer to home, the chemicals were clearly accumulating in their own factories. By 1976, 3M measured fluorochemicals in the blood of workers at its plant in Cottage Grove Minnesota at “1,000 times normal.” The chemical appeared to accumulate in animals, too. Mice fed “Scotchban,” a grease-proofing 3M product that contained PFOS, had “4,000 times normal organic fluorine compound,” in their blood, the timeline also noted. By 1979, the company noted that samples from Red Cross blood donors also contained trace levels of the fluorinated chemical.

But it’s clear that the scientists’ fielding Guy’s phone call had yet to grasp the implications of the situation. After the call, Crawford tried to put a positive spin on the dawning realization that their chemical had found its way into Americans’ blood.

“If it is confirmed to our satisfaction that everybody is going around with fluorocarbon surfactants in their bloodstreams with no apparent ill-effect, are there some medical possibilities that would bear looking into?” Crawford asked in his notes. Perhaps PFOS might help with hardening of the arteries, “kidney blockage, senility and the like,” Crawford mused, going on to suggest animal experiments “both from a defensive point of view and for the above (to me) intriguing reasons.”

While the company was pondering the possibility that the massive human experiment it had launched might have some positive outcomes, it was becoming clear that it would almost certainly have some negative ones. According to minutes from a 1978 meeting about 3M’s experiments on rats and monkeys, PFOA and PFOS “should be regarded as toxic.” Disturbingly, PFOA caused changes in rats’ livers at levels lower than that measured in one of its workers, according to the memo, which described the finding as suggestive of “a possible human health problem.” Nevertheless, the eight staff members present at the meeting decided that the toxicity “does not constitute a substantial risk and should not be reported [to the EPA] at this time.”

Two studies on monkeys done later that year might have been seen as even more alarming — and worth sharing with the public. One had to be stopped because all the monkeys given PFOS died (“Incorrect (too high) feeding levels were used and all animals died within the first few days”). In the other, monkeys given PFOA developed tiny lesions on their spleen, lymph nodes, and bone marrow — organs central in maintaining the body’s immune defenses.

The next year, a review of the internal studies described PFOS as “the most toxic” of three compounds studied, “certainly more toxic than anticipated,” and recommended that “lifetime rodent studies should be undertaken as soon as possible.” But from the documents released and a search of the medical literature, 3M appears not to have undertaken the studies suggested in the review. Nor did it publish either of the monkey studies. And the company waited 22 years before giving the troubling studies to the EPA or reporting the evidence that the chemical was in the blood of the general public.

Still, 3M appears to have been worried enough about the implications of the studies to seek advice from a well-known toxicologist named Harold Hodge. At a confidential meeting with company executives held in San Francisco in June 1979, Hodge noted that the company’s research on exposed workers showed “indications of liver effects.” Because both PFOS and PFOA also caused liver changes in rats, Hodge suggested that 3M find out whether PFOS “or its metabolites are present in man, what level they are present, and the degree of persistence (half-life) of these materials.” If the levels were high and widespread and the half life long, he said, “we could have a serious problem.”

In a phone call a week after the meeting, Hodge asked that a note be added to the minutes to stress that the research he was proposing was “of utmost importance.” Later that year, another 3M scientist, M. T. Case, underscored Hodge’s suggestion, writing in a memo to his colleagues that “it is paramount to begin now an assessment of the potential (if any) of long term (carcinogenic) effects for these compounds which are known to persist for a long time in the body and thereby give long term chronic exposure.”

In 1980, the company came close to disclosing how widespread its chemicals had become, according to questions drafted in anticipation of the news reaching the general public. “I have heard that fluorochemicals are persistent. Does this mean that [they] are like PCBs and DDT?” one sample question asked, referring to chemicals widely used in electrical equipment and pesticides, respectively, that accumulated in the environment and increased cancer rates. The proper answer, according to the company’s guide was “NO.” But it turned out no rehearsal was necessary. 3M didn’t announce the presence of PFOS or PFOA in human blood — nor did the bad news leak out. And for more than 20 years, as evidence emerged that tumors in exposed lab animals were related to PFOA exposure, that the levels of the chemicals in 3M workers’ blood rose over time, and that their cancer rates were elevated compared to the general population, the questions about the environmental and health consequences of the secret were neither asked nor answered.

A view of the U.S. Environmental Protection Agency headquarters on March 16, 2017, in Washington, D.C.

Photo: Justin Sullivan/Getty Images

What Immune Impact?

The real-life implications of this careful curation of the scientific record on PFAS is still coming into relief as the public begins to grapple with the likelihood that the EPA’s safety levels for these two chemicals are far too high. A study released by the Agency for Toxic Substances and Disease Registry in June calculated that the limit for PFOS and PFOA in drinking water ought to be around 7 and 11 parts per trillion or ppt, respectively, just a fraction of the 70 ppt that the EPA set for the chemicals in 2016.

ATSDR and the state of New Jersey, which has calculated similar safety levels for both chemicals, arrived at the lower number for PFOS in part by including studies showing that very low levels of the chemical affect the immune system. The European Food Safety Authority also recently considered evidence of their immune effects when calculating even lower safety levels — 6.5 ppt for PFOS and just 3 for PFOA. And Philippe Grandjean, a physician and environmental health scholar who has studied the immune effects of PFAS and provided expert testimony for Minnesota in the 3M case, calculated that the safety levels for both PFOS and PFOA should be less than 1 ppt.

In contrast, the EPA did not include studies showing immune effects in its calculations. When asked why it didn’t include these studies when devising its health advisory levels for PFOS and PFOA, the EPA did not respond. The agency instead provided the following statement:

EPA remains committed to evaluating PFOA and PFOS under the regulatory determination process using the best available science. As a part of the evaluation, EPA will be reviewing all newly available scientific information including the ATSDR report. EPA is taking steps to accelerate the determination process before the existing statutory deadline.

The statutory deadline is 2021.

While the immune effects of PFOS and PFOA have entered the public conversation only in recent years, 3M has possessed evidence suggesting that its signature chemical affected the immune system as far back as 1978, when its monkey study showed the tiny lesions on immune organs. An internal summary of research noted both PFOA’s liver and immune effects. At a 1983 meeting of the company’s Fluorochemical Study Committee, a member of the toxicology team listed “immunosuppressive effects” as one of three areas of follow-up research given the highest priority, according to meeting notes.

Yet the company didn’t publish anything about how PFOA affected the immune system, even as it was internally gathering more damning evidence. In 1991, a physician named Frank Gilliland came to work at 3M for a year while he was getting his Ph.D. in environmental health. Gilliland wrote his thesis on the health effects of PFOA in 3M workers in 1992, looking at the effects of the chemical on 115 male workers at one of the company’s plants.

The paper describes his finding that the amount of PFOA in workers’ blood correlated to levels of various hormones. Gilliland also calculated that workers in one of 3M’s plants who had at least 10 years of exposure to PFOA had a death rate from prostate cancer that was three times that of workers who weren’t exposed to PFOA. And his thesis explained that the chemical affected the immune response to foreign chemicals.

While Gilliland went on to publish the prostate cancer finding, an internal paper he wrote that further explored PFOA’s effects on the workers’ immune system never saw the light of day. His draft explained that the level of critical immune cells in workers was “significantly correlated” with their total fluoride levels, “suggesting that cell-mediated immunity may be affected by PFOA.” Gilliland’s paper also noted the company’s 1978 monkey studies — and that “no follow-up studies of these observations have been reported.”

But the company didn’t publish or follow up on Gilliland’s work either, based on the documents released. In a 1993 memo, 3M’s medical director, Jeff Mandel, wrote to the company’s Fluorochemical Steering Committee members that Gilliland had three research papers in the works, all of which were “negative for the most part.” Mandel wrote that “we’re working with him regarding some of the wording.” But none of the papers in the memo came out in any form. And 15 years would pass after Gilliland’s finding that PFOA affected immunity — and 30 years after the monkey study suggested a similar impact — before independent scientists documented the effect of PFOA in humans.

One of the reasons scientists in the field didn’t explore whether PFOA, PFOS, and other chemicals in their class could affect the body’s ability to fight off infection and toxicity was because they believed they couldn’t affect the human body. “Word was that the compounds were inert,” said Grandjean, who considered and rejected the idea of researching how the chemicals affected immunity when 3M took the compounds off the market in 2000.

It was only in 2008, after a study showed that PFOA affected the immune systems of mice, that Grandjean and his team went back to study the chemicals’ impact on humans. “We were already looking at PCBs, which we know are immunotoxic, to see if they affected how children responded to vaccines,” said Grandjean. When his team did the same research with PFAS, they noted a dramatic effect. “These responses were much stronger than anything we can attribute to PCBs.”

Tennessee Wildlife Resource Agency biologist Bobby Brown investigates Feb. 22, 2018, after tens of thousands of fish died in a small, unnamed tributary running parallel to DuPont Parkway in the community of Hixson, Tenn. The small stream feeds into the Tennessee River across from the Tennessee Riverpark in Chattanooga.

Photo: Mark Pace/Chattanooga Times Free Press via AP

Eagles, Fish, and Rats

Another 3M scientist made discoveries about PFAS that the company didn’t readily follow up or publish. In the 1990s, Rich Purdy, an environmental scientist at 3M, detected PFOS in the blood of eagles. He also found that rats that hadn’t been purposely exposed to the chemical had it in their liver, likely because their food was made from fish that had been exposed. (3M had already measured the chemicals in fish in the Tennessee River near its Decatur, Alabama plant back in 1979.) Alarmed, Purdy reasoned that whales, seals, and other fish-eating animals might also be contaminated and urged the company to sample a few species to find out. But his superiors didn’t share his urgency.

“I’m not sure there is a need to support or refute the hypothesis within any particular time frame,” a 3M attorney named Thomas DiPasquale wrote to his colleagues in the company’s corporate division in a 1999 email. Purdy had also suggested alerting the EPA to his concern that PFOS was spreading through the food chain, but his bosses came up with a slower and more measured response.

The year before, the company had laid out its strategic plan for releasing scientific information. In 1998, it had finally provided the EPA with some of the evidence that its chemicals were in blood samples from the general public. In anticipation of the public release of that information, 3M devised a schedule of publications that would “allow the serum level findings to be placed in an understandable, credible context which demonstrates that there is no medical or scientific basis to attribute any adverse health effects to 3M products.”

Purdy believed that the plan to delay the follow-up was another instance of putting the company’s need to protect its self-interest over the environment:

Plan! That is the same stalling technique you have been using for the last year. There is a high probability that PFOS is killing marine mammals and you want another plan when we could have had data to support the risk assessment long ago. You were given a plan in 1983. Again in the early 90s. And you authorized no testing …

You continually ignore our plans and start new plans that slows the collection of data essential for our risk assessments. You slow our progress in understanding the extent of PFOS pollution and damage. For 20 years the division has been stalling the collection of data needed for evaluating the environmental impact of fluorochemicals.

Shortly afterward, Purdy reached his limit, according to a resignation letter he sent in 1999. In it, he explained that his decision to leave was “prompted by my profound disappointment in 3M’s handling of the environmental risks associated with the manufacture and use” of PFOS. While, years before, the company’s planned questions and answers had sought to dispel any comparison to PCBs, Purdy described PFOS as “the most insidious pollutant since PCB.”

I have been assured that action will be taken — yet I see slow or no results. I am told the company is concerned, but their actions speak to different concerns than mine. I can no longer participate in the process that 3M has established for the management of PFOS and precursors. For me it is unethical to be concerned with markets, legal defensibility and image over environmental safety. …

3M told those of us working on the fluorochemical project not to write down our thoughts or have email discussions on issues because of how our speculations could be viewed in a legal discovery process. This has stymied intellectual development on the issue, and stifled discussion on the serious ethical implications of decisions.

I have worked within the system to learn more about this chemical and to make the company aware of the dangers associated with its continued use. But I have continually met roadblocks, delays, and indecision. For weeks on end I have received assurances that my samples would be analyzed soon — never to see results.

Purdy later changed his mind and returned to work at the company, according to a letter from his wife, who was clearly troubled by his decision. He didn’t respond to requests for comment. In any case, within a year of his letter, everything had changed. In 2000, after giving the EPA hundreds of its studies, 3M announced it would cease production of PFOS and PFOA. While the company claimed it made the decision voluntarily, an EPA official at the time said that the agency was prepared to remove PFOS from the market based on research that “suggests to us is that there are potentially long-term consequences.”

Subsequent research has validated the EPA’s suspicion. Since 2000, the number of scientific articles published on the health effects of PFAS has increased more than tenfold. The findings have linked the chemicals to a wide range of health effects in people, including testicular and kidney cancer, obesity, impaired fertility, thyroid disease, and the onset of puberty. The increased cholesterol and lipids in blood that Olsen noted in his 2001 paper have also been identified in several recent studies. And the immune effects have also been borne out, with one recent study by Grandjean showing that levels of the chemicals in infants’ blood were related to their immune response at age 5.

But the lag in awareness of these problems makes addressing them infinitely harder than it would have been when they had first surfaced. It’s now too late to contain the chemicals that originated in 3M’s laboratories. Since PFAS compounds were first traced in a few workers and animals, the chemicals have gone from being an occupational hazard to one shouldered by everyone. Blood testing done in 2003 found PFOA in 99.7 percent of more than 2,000 samples in the U.S. PFOS was in 99.9 percent. And it’s not just those two chemicals. In 2005, 3M tested human blood from around the country for 15 different PFAS — and found 14 of them.

The number of people thought to be affected by this contamination continues to expand as the scientific information is refined. In Minnesota, where 3M is headquartered and the lawsuit was filed, the plume of PFAS that was first detected in the 1960s as leaching from a few landfills now covers 100 square miles of groundwater and affects the drinking water of some 125,000 people in the Twin Cities area.

PFAS water contamination is now a national — and international — issue. Using data collected by the EPA, the Environmental Working Group calculated that more than 100 million Americans may be have some level of PFAS in their drinking water.

3M insists that “the presence of PFAS in blood does not mean that an individual’s health has been harmed and does not mean that there is a risk of adverse health effects. While the science behind PFASs is complex, the vast body of scientific evidence, which consists of decades of research conducted by independent third parties and 3M, does not show that PFOS or PFOA negatively impact human health at the levels typically found in the environment,” according to a statement the company provided in response to questions for this story.

But even as the company has continued to defend its chemicals, 3M’s legal problems have mounted along with the scientific evidence. States, counties, and individuals have filed dozens of suits against the company over the past two years, many of them based firefighting foam that contain PFAS chemicals.

Even if victory awaits those plaintiffs — as a form of it did in Minnesota — it’s not clear that justice will be done. The state will be using its $850 million settlement from 3M to address its massive water contamination problem. But it will be impossible to fully remove the chemicals from the groundwater or lakes or the Mississippi River, or any of the areas where it’s contaminated groundwater.

The people living in these places — and grappling with the realization that they have been ingesting these chemicals for years — have no recourse. “We don’t have some wonder medicine,” said Grandjean. “When I talk to residents about this, I convey the bad news. I’m a physician. I thought I was getting into medicine to solve problems. But all I can do is say, you’ve got this stuff in your body and it’s going to stay there for a long time and there’s nothing we can do about it.”

While there’s no way to go back and undo the environmental and health damage that’s already been done, criminal prosecutions could help prevent a similar situation in the future, according to Rena Steinzor, a professor at the University of Maryland School of Law and author of “Why Not Jail? Industrial Catastrophes, Corporate Malfeasance, and Government Inaction.”

“Criminal law allows us to go after people right now who withhold information they’re supposed to give the government,” said Steinzor. “If lying to the government is prosecuted as a crime with respect to the chemical industry — as it should be — things will get better quick.”

Whether such environmental misconduct might be taken more seriously in the future, 3M’s failure to act sooner on the danger of PFAS still has yet to be fully addressed. Geary Olsen, whose published paper omitted the finding detailed in his internal study, continues to work at 3M. 3M declined to make Olsen available for comment. John Giesy has stayed on as a professor at the University of Saskatchewan, even after it was revealed that he spun the science on PFAS after receiving more than $2 million in grants from the company. And Rich Purdy, who was so distraught by the company’s delays in releasing his research, recently prepared to testify for 3M, according to his wife.

Some researchers, like Frank Gilliland, who detailed the immune impacts of PFOA in his graduate thesis, left 3M “less idealistic” than when he began his work there, he told me in a recent interview. Reached at the University of Southern California, where he is now a professor of medicine, Gilliland said that PFOS and PFOA “should have come off the market sooner.” He said his current academic setting, in contrast to 3M, was a place of “free-ranging scientific inquiry.”

Philippe Grandjean, who has been a physician and environmental health researcher for more than 40 years, has also been affected by the realization of just how long he and others were kept in the dark about the harms of the chemicals. “I lost my confidence in the scientific literature,” said Grandjean. As he sees it, his whole profession has been stained by the experience. “We in my field have failed.”