ROCKFORD, MICHIGAN—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."
An unbreakable bond
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.
The C8 study was a gold mine, says Richard DeGrandchamp, a toxicologist at the University of Colorado Anschutz Medical Campus in Aurora, who was not involved in the work. "I'm not aware of any major studies in the history of epidemiology and toxicology where we've had such a large … group of people who have been exposed."
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.
After that meeting, Tompkins learned through a public records request that the tannery had once stored Scotchgard and other chemicals in tanks without secondary containment. And after hearing that state officials planned to sample for PFASs at other Michigan sites, CCRR asked whether they could also check the Rogue River. The officials agreed and, in 2015, reported finding elevated levels of PFOS in smallmouth bass and white suckers living downstream of the tannery.
"The fish study was seminal for us" because it suggested the tannery had contaminated offsite areas, says A. J. Birkbeck, a Grand Rapids, Michigan–based environmental attorney and hydrogeologist who represents CCRR. The study also gave Rediske the data needed to build a case for action. "I decided I'd really get involved when I got those results," he recalls. (Wolverine says it is now collecting environmental data at the tannery site and is working on a filtration system to treat groundwater at the site before it reaches the Rogue River.)
The group suspected the river wasn't the only off-site area touched by tannery waste. McIntosh, for instance, had interviewed a former waste hauler named Earl Tefft, who told her that in the 1960s he had spent every day for a year hauling large containers of sludge from the tannery to nearby dump sites. One was on a Wolverine-owned property about 8 kilometers from Rockford on House Street, a woodsy lane dotted with homes that drew their drinking water from private wells. In early 2017, CCRR alerted state officials to the historic dump, fearful that the waste could be contaminating nearby wells.
Wolverine tested the wells later that year, and the results were explosive. One water sample had a combined concentration of PFOA and PFOS of 27,600 parts per trillion (ppt), nearly 400 times greater than EPA's suggested level of concern at the time. It was the highest concentration state toxicologists had ever seen in a well, reported journalist Garret Ellison of the Grand Rapids Press team at MLive, who has extensively covered PFAS contamination in Michigan.
The House Street contamination garnered national attention. It appeared to explain why federal officials had found PFAS contamination at a nearby military facility, also on House Street, which had no history of using the chemicals. "Had CCRR not essentially supplied all of the connective tissue … it would have been quite some time before [regulators] put the pieces together" and identified the likely source of the distant pollution, Ellison says.
Wolverine declined to comment when asked whether it believes the PFAS contamination in the House Street wells stems from its nearby dump. But the company did outline actions it has taken to ensure safe drinking water for residents. It says it has given water filters to more than 700 homeowners, has sampled more than 1500 residential wells, and is monitoring water contaminant levels at more than 500 homes.
Had CCRR not essentially supplied all of the connective tissue … it would have been quite some time before [regulators] put the pieces together.
In November 2017, Michigan officials responded to the results from House Street and elsewhere by launching the most comprehensive statewide survey of PFAS contamination. It analyzed samples from every public water system, as well as groundwater, surface waters, soils, sediments, foam, fish, and other wildlife. The survey showed nearly 1.4 million residents were drinking water from sources contaminated with PFASs. In Parchment, a city in southwestern Michigan, PFAS concentrations in drinking water were so high—1600 ppt—that the governor declared a state of emergency.
As public and official concern escalated, Rediske emerged as a go-to expert for journalists and community groups wanting to learn more about PFASs. He was willing to appear on television, Birkbeck says, "and he had the expertise to say, ‘We've got a real issue here.’" U.S. Senator Gary Peters (D–MI) even invited Rediske to testify at a public field summit that a committee Peters serves on held in Michigan. Rediske's testimony, Peters says, "was important [in] assessing what more needs to be done to support local and state efforts" to address PFASs.
Michigan wasn't the only state grappling with the issue. And in Washington, D.C., Congress and newly elected President Donald Trump's administration were struggling to answer an increasingly urgent question: What is a safe PFAS level, especially in water people drink every day?
A push to set limits
So far, no one is certain. In 2016, after reviewing studies on the possible health impacts of PFASs, EPA lowered its nonbinding advisory standard for drinking water from 400 ppt for PFOA and 200 ppt for PFOS to 70 ppt for both combined. But some researchers and public health advocates argue that level is too lax. Their views got a boost in June 2018, when the Centers for Disease Control and Prevention (CDC) released a long-awaited assessment of 14 PFASs. It recommended "minimal risk" levels for PFOA and PFOS, which the agency later converted to recommendations for drinking water limits. For children, those levels are 21 ppt for PFOA and 14 ppt for PFOS—notably lower than EPA's advisory level. (Trump administration officials discussed trying to block release of the CDC report, fearing it would create a political firestorm.)
CDC's assessment was based, in part, on prospective studies in which researchers monitored people with known PFAS blood levels to see whether exposure was statistically linked to health issues. In one such study, published in PLOS Medicine in February 2018, higher PFAS levels were associated with greater weight regain among participants in a 2-year weight loss trial. In a second prospective study, published in Environmental Health Perspectives in March 2018, researchers found that women with higher blood levels of PFOS and PFOA were at greater risk of developing type 2 diabetes.
Researchers don't fully understand the biological mechanisms that might explain such findings, and that uncertainty has helped fuel debate over safe PFAS limits. At the federal level, for instance, EPA has so far declined to embrace the CDC recommendations. Yet at least one researcher, environmental health specialist Philippe Grandjean of Harvard University's T.H. Chan School of Public Health in Boston, says even CDC's recommendations are too high. He believes protecting children's immune systems would require a drinking water limit of just 1 ppt or less.
Political and economic considerations also are coloring the debate. In general, EPA is not supposed to consider cost in setting pollution limits. But when the agency proposed its 70-ppt advisory level, its own surveys suggested the real-world impact would be minimal because few drinking water supplies were known to have concentrations exceeding that level. Newer surveys suggest many water supplies have some level of PFAS contamination, however, which could create pressure for expensive cleanups if limits are lowered.
Industry groups question the need for stricter regulation. In Michigan, for example, Wolverine hired a toxicologist who downplayed the risks associated with PFASs. "Human health effects from exposure … are unknown," wrote Janet Anderson of Integral Consulting in San Antonio, Texas, in a November 2017 Wolverine blog post. "No human study … has been conducted that proves exposure of an individual to any PFAS … causes any illness."
After the CDC report became public, however, the Trump administration—under growing pressure from Congress and state officials—promised to take action. And in February, EPA released a plan that calls for formally setting regulatory limits for PFOA and PFOS and for launching a nationwide program to monitor PFASs in water systems. The agency said it will beef up research into detection and cleanup methods, consider requiring companies to report PFAS releases, and even consider banning certain compounds.
EPA also is planning to intensively examine about 125 of the thousands of newer, less studied PFASs, in collaboration with the National Toxicology Program. One goal is to test the assumption that the newer compounds are safer because they have shorter lives. "We all need to remember that because something doesn't bioaccumulate doesn't mean it won't be a problem if you're exposed to it, say, in your drinking water every day," said Linda Birnbaum, director of the National Institute of Environmental Health Sciences in Durham, North Carolina, at a recent press briefing.
In the absence of swift federal action, many states are taking charge. New York has proposed setting a maximum level of 10 ppt for PFOA and PFOS in drinking water, whereas New Jersey is considering slightly higher limits. Vermont lawmakers passed a bill that would set a 20-ppt limit for a combination of five PFASs. Pennsylvania has launched a statewide contamination survey, having already identified more than 300 public water supplies with "an elevated potential for contamination." And in Michigan, Governor Gretchen Whitmer (D) in March declared that she could "no longer wait for the Trump administration to act" and will propose state drinking water standards for some PFASs.
Meeting such new standards could be costly. In New York, officials have estimated that compliance, including equipping water utilities with treatment systems, will cost from $900 million to $1.5 billion. To help defray expenses, some states are suing PFAS polluters. Last year, Minnesota settled a case against 3M for $850 million, which will be used to help provide clean water to affected residents.
Here in Michigan, lawsuits also are underway. More than 200 families living on and near House Street, for instance, are suing Wolverine and 3M. Among the many legal questions is whether the plaintiffs can show they were harmed by exposure to PFAS-contaminated water. If the families win, it could open "the floodgates to more lawsuits and the ability of private citizens and states to sue," says attorney Paul Albarran of Varnum, the Grand Rapids–based law firm representing the families.
In March, state and federal regulators formally validated the sleuthing by McIntosh and CCRR: They officially confirmed that the former tannery site and nearby waste disposal areas are laced with PFASs. The announcement was made at a town hall meeting at Rockford High School. McIntosh and Birkbeck sat in the front row. Rediske, Tompkins, and other CCRR members were also in the crowd. As McIntosh listened, she was struck by how closely the contamination maps that officials presented matched the informal maps she'd drawn based on interviews with former tannery workers.
During the meeting, Rediske urged residents to become involved in a new community advisory group that will help oversee the next chapter in the tannery's history: a long, complex cleanup. Given the role that concerned citizens have already played in resolving past contamination problems in Michigan and beyond, Rediske said he was confident they could also rise to the new challenge: "It can be done."