Read the full article by Sara Talpos (AAAS)

“For more than a century, a sprawling tannery here on the banks of the Rogue River churned out leather used to make some of the country’s most popular shoes. The factory emitted a putrid stink, but it enabled this city of roughly 6000 people to thrive. ‘That’s the smell of money,’ some locals used to say.

In 2009, however, shifts in the shoe trade prompted the tannery’s owner, Wolverine Worldwide, which is based here, to close the facility. In a 2010 request for state funds to help redevelop the 6-hectare site, which sits astride a picturesque business district, lawyers representing the company stated: ‘There is no known contamination on the property.’

Lynn McIntosh, a piano teacher and writer who has lived just a block from the tannery for more than 25 years, was skeptical. The statement was ‘legalese laced with hogwash,’ she recalls thinking when she read it. Tanneries use a stew of hazardous chemicals to transform raw hides into leather, she knew, and sometimes left contamination behind. For that and other reasons, McIntosh and others asked city and state officials to require a comprehensive environmental study of the site before it was redeveloped.

Their plea was rebuffed, so she and a small band of allies launched their own investigation. The group, which ultimately named itself Concerned Citizens for Responsible Remediation (CCRR), collected maps, dug into newspaper archives, and filed requests for public records. Members spoke with scientists knowledgeable about tannery chemicals and hired an environmental attorney with a background in geology to help them strategize. McIntosh even staked out and photographed the demolition of tannery buildings, followed waste trucks to dump sites, and interviewed retired tannery workers. The years of effort yielded stacks of documents that McIntosh—who prefers a simple clamshell cellphone to modern smart screens and paper files to the digital cloud—lugged to meetings in heavy bags.

Now, that sleuthing is having far-reaching impacts in Michigan and beyond. The concerned citizens uncovered evidence that the tannery had contaminated large swaths of land and water with chemicals known as a per- and polyfluoroalkyl substances (PFASs), which researchers have linked to an array of human health problems. More than 4000 such compounds exist, and they are widely used in products such as fire-fighting foams, nonstick coatings, carpeting, food packaging, and even dental floss. The tannery used two PFASs by the ton to waterproof shoe leather. In a statement to Science, Wolverine said that when it submitted its application for state redevelopment funds in 2010, it did not know any of the chemicals had leaked. ‘There was no testing or other environmental data for the former tannery, and no basis to conclude that there was contamination on the property.’

CCRR’s work led to the detection of some of the highest levels of PFAS contamination in U.S. drinking water, and the effort helped trigger an unprecedented statewide survey of PFAS contamination in Michigan. The work has led to hundreds of lawsuits against Wolverine and other entities linked to the chemicals. And it has made Michigan a high-profile, closely watched battleground in a rapidly expanding scientific, political, and legal dispute over the threat that PFASs pose to millions of people in the United States.

The events in Michigan show ‘that when you look hard … you’re going to start finding [PFASs] showing up everywhere,’ says attorney Erik Olson of the Natural Resources Defense Council in Washington, D.C. Around the country, evidence of PFAS contamination has anxious residents demanding to know how exposure could affect their health. Regulators are struggling to balance cost and risk as they set safety limits. And companies, fire departments, water utilities, and the U.S. military are facing cleanup and liability costs that could total tens of billions of dollars or more.

McIntosh and her colleagues—including a toxicologist who works at a nearby university—now find themselves in the public spotlight in ways they never imagined nearly a decade ago. ‘I had no idea,’ McIntosh says, ‘this would be so big.’…

At the heart of the PFAS controversy is the carbon-fluorine bond, among the strongest of all chemical bonds. Enzymes can’t break it. Sunlight can’t break it. Water can’t break it. That durability explains the commercial appeal of PFASs, but it makes them problematic pollutants. They’ve been dubbed ‘forever chemicals’ because they don’t degrade naturally. And because the molecules have a water-soluble head, water and airborne droplets can carry them for long distances.

The U.S. chemists who discovered how to synthesize PFASs in the 1930s, however, were beguiled by their advantages. Use of the chemicals in the United States began to expand rapidly during the 1950s, when the Minnesota Mining and Manufacturing Company, a Saint Paul–based firm now called 3M, began to sell two compounds: perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). PFOA became the basis for Teflon, the ubiquitous nonstick cookware coating manufactured by DuPont. PFOS became a key ingredient in firefighting foams used at airports and military bases and in the popular Scotchgard protectant, which enabled fabrics and other materials to resist water and oils.

At Wolverine, Scotchgard played a notable role in the success of one of the company’s iconic shoe lines: Hush Puppies. Thanks to PFASs, the casual pigskin shoes, introduced in the 1950s, were waterproof. They were a best-seller, helping transform Wolverine into a multibillion-dollar company that today holds a portfolio of shoe brands that includes Merrell, Saucony, Stride Rite, and Keds.

Even as sales of PFOA and PFOS boomed, however, 3M and DuPont researchers were amassing evidence that the chemicals accumulated in people and other animals and could have toxic effects. Much of that evidence became public only because of a lawsuit. In 1980, DuPont purchased farmland in West Virginia and began to dump waste laced with PFOA there. Cattle that grazed nearby began to die, and in 1999 a local family sued the company. The proceeding forced DuPont to hand over internal files, which the family’s attorney, Rob Bilott of Taft Stettinius & Hollister in Cincinnati, Ohio, shared with the Environmental Protection Agency (EPA). In 2001, DuPont paid an undisclosed sum to settle the case, and EPA fined the company in 2005 for violating rules for toxic waste. Under pressure from EPA, U.S. manufacturers agreed in 2006 to phase out production of PFOA by 2015. (They ended PFOS production in 2002.) Often, the two chemicals were replaced by related PFASs that manufacturers have asserted are safer and break down faster.

Bilott also helped launch a major study of PFASs’ potential health effects. In 2001, he sued DuPont again on behalf of 80,000 people in Ohio and West Virginia served by water sources contaminated with PFOA. In a settlement, DuPont agreed to pay up to $70 million for the study, dubbed the C8 Health Project because PFOA was once called C8 after the molecule’s chain of eight carbon atoms. Beginning in 2005, a team led by a local physician recruited more than 69,000 participants, who answered interview questions, filled out questionnaires, and gave blood samples. In 2011 and 2012, three independent epidemiologists who analyzed the data issued reports indicating a probable link between PFAS exposure and six conditions: high cholesterol, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer, and pregnancy-induced high blood pressure…

Meanwhile, other researchers were finding that almost all people living in the United States carry detectable levels of PFASs in their blood (although levels of PFOA and PFOS have declined since they were phased out). And the more researchers looked for PFAS contamination around industrial sites, airports, and military bases, the more they found. But when the concerned citizens began to investigate the tannery here in 2010, they’d never heard of forever chemicals…

Rick Rediske was hesitant. The environmental chemist had listened intently as two members of CCRR—McIntosh and Janice Tompkins, formerly of Michigan’s Department of Environmental Quality—described their investigations into the tannery, just a 30-minute drive from his office at the Allendale campus of Grand Valley State University. ‘I was impressed with the level of detail they had amassed,’ he recalls about the 2012 meeting.

The two women offered photographs of hides and leather scraps embedded in the bank of the Rogue River, where their chemical contents could leach into soil and water. The pair also had pictures of potentially contaminated stormwater flowing off the tannery site during demolition and into the river. They shared CCRR’s interviews with former tannery workers about the facility’s use of chemicals and waste disposal practices. McIntosh showed Rediske a map of potential problem areas that she had drawn based on the interviews, including spots where chemicals might have leaked from the tannery through cracked floors and broken pipes. (During her first interview, with a former tannery employee in his 80s, McIntosh learned that Scotchgard had been used to treat the leather.)

When the two women asked Rediske whether he could help test for contaminants from the tannery, however, the 66-year-old professor hesitated. He didn’t have funding to conduct such expensive studies. More important, he wasn’t eager to tangle with the law firm representing Wolverine. In the 1990s, after he documented pollution at a Michigan tannery owned by a different company, the same law firm had used public records requests to obtain his emails, technical memos, and laboratory notebooks—and hired consultants to aggressively challenge his findings. His work had withstood the scrutiny and helped state officials win a $3 million cleanup settlement. But the experience was taxing. ‘Scientists spend their careers building their reputations,’ he says. ‘Providing contrary opinions against powerful business and governmental interests has both monetary and professional costs.’ Still, he offered to advise CCRR…”

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