In a Minneapolis courtroom next week, nine jurors and battalions of attorneys will finally meet in a titanic legal clash between the state of Minnesota and the 3M Co. over a 100-square-mile plume of polluted groundwater in Washington County.

The lawsuit turns on Minnesota's assertion that 3M knowingly contaminated the drinking water of several east metro communities, causing up to $5 billion in potential damage to property values, wildlife and human health.

But a victory for Attorney General Lori Swanson could push the stakes much higher — tarnishing the reputation of one of Minnesota's most revered corporations and creating momentum for other lawsuits.

Some attorneys say it could begin a global reckoning for 3M and the slippery, nonstick chemicals known as PFCs that eased the lives of a generation of consumers and helped industries around the world.

Though 3M has consistently denied wrongdoing — and has so far successfully thwarted liability claims in several courtrooms — the company is now a defendant in 37 similar lawsuits across the country. The products it made at its Chemolite Plant in Cottage Grove are also the focus of hundreds of environmental investigations and a host of new scientific studies measuring their health impact on communities from New Hampshire to Alaska.

3M officials say they followed the law in disposing of their factory wastes, acted responsibly at all times and expect to successfully defend the company in all the cases.

"We believe that 3M's record of corporate stewardship is unparalleled," the company said. 3M was the first company to stop making PFCs, and it has invested significantly in environmental cleanup and research, the statement said.

Nonetheless, Wall Street analysts, public health officials, scientists and, most of all, attorneys from across the country will all be listening.

If 3Mloses?

"That could be the first ripple in a tidal wave of verdicts against it," said Kevin Madonna, a New York attorney who is representing local drinking water systems contaminated by PFCs.

A biological threat

Either way, it's been a long time coming.

3M invented perfluorinated chemicals — known as PFCs — in the 1950s. A synthetic combination of fluoride, carbon and other molecules, PFCs produced a nonstick compound that proved to be extraordinarily strong, long lasting and useful. The chemicals made carpeting, clothing and furniture resistant to dirt and water. They helped make Teflon a household name. They were miraculous in suppressing fires. And by 2000, they were bringing 3M more than $300 million in annual revenue.

But those same extraordinary qualities made them a biological threat in the natural world. PFCs dissolved easily in water and adhered to soil, which allowed them to spread far and wide. Even more alarming, they accumulated in the bodies of fish, wild animals and humans and seemed to never break down. A half-century of widespread industrial use and disposal into porous landfills and rivers like the Mississippi have swept them across the globe, even into Arctic regions, where they have turned up in the blood of polar bears.

"When something persists, it deserves our attention," said Jennifer Field, a toxicologist at Oregon State University who studies PFCs.

In 2000, after years of escalating concern among scientists and under pressure from the U.S. Environmental Protection Agency, 3M agreed to stop making PFCs.

In Minnesota, however, their legacy continued — in groundwater tainted by four dump sites in Washington County. In 2007, 3M signed a landmark agreement with Minnesota to spend millions of dollars cleaning up landfills and providing new drinking water to affected communities.

Nevertheless, Swanson sued 3M in 2010, demanding payment for damage to the state's natural resources.

"Let's make it right," she said at the time.

3M says it already has made it right by honoring legal obligations set out in its earlier agreement with the state. Moreover, it said, its manufacturing and disposal activities in Minnesota were legally permitted at the time.

But since 3M and the state signed their agreement, the concerns over PFCs' environmental and health effects have grown exponentially.

In 2016, the EPA drastically lowered the maximum levels of PFC concentrations recommended for drinking water — and an estimated 15 million people instantly found that their drinking water was no longer considered safe for long-term consumption.

Increased risks

The agency was responding to a steady series of epidemiological studies that found that high PFC levels in the body appear to increase the risks of testicular and kidney cancer, liver damage and high cholesterol. Children with higher PFC levels appear more prone to infections, and pregnant women can be more likely to deliver low birth-weight babies. Animal studies have shown even stronger evidence of cancer and other significant health problems.

3M officials say the EPA guidance levels — and even lower levels adopted by Minnesota and other states — are merely cautionary. There is no evidence, they say, that PFCs cause cancer or other health effects in humans at the levels found in the environment.

Still, the federal health advisory sent communities across the country scrambling to install expensive water treatment technology — and to find who dumped the PFCs that were contaminating their drinking water.

"Any settlement received from [Minnesota's] litigation with 3M should be directed to the cities impacted by PFC contaminants," said Charlene Stevens, city administrator in Cottage Grove. Last year the city spent $2 million on a water treatment system to comply with the new health advisory and is pushing for a new $50 million treatment plant for the entire affected area in south Washington County.

Madonna represents two communities in Massachusetts, one of which has already spent $3 million to filter drinking water contaminated by 3M's firefighting foam from a nearby fire training center.

"It's a mess," he said. "The town sued the county, saying the county is responsible, so the county sued 3M."

The U.S. Defense Department is investigating groundwater contamination at about 400 military sites around the country where firefighting foam with PFCs was used for years; so are an unknown number of smaller airports and training facilities. Some 20 of the 37 cases pending against 3M are related to firefighting foam.

Crucially, Madonna said, most of those facilities were probably using the foam as the manufacturers advised. "The potential liability for 3M is staggering," he said, noting that the company was a major supplier to the military.

Tests in Colorado Springs

In Colorado Springs, 3M is the defendant in a giant lawsuit that combined several individual actions related to firefighting foam used on an air base. The National Institutes of Health has just announced funding to measure PFC levels in the blood of nearby residents.

Investigations are underway in other places. Communities around the former Pease Air National Guard Base in Portsmouth, N.H., now an industrial park where 10,000 people go to work and send their kids to two day care centers, are still struggling to understand the implications from longtime exposure to contaminated drinking water.

"That worries me when I look at my children, who were exposed to these contaminants at such a critical time in their development," said Andrea Amico, a community activist appointed to an Air Force advisory panel. So far, no manufacturer has been identified.

"We can't get a straight answer on that" from the military, Amico said. "But someone should have had a moral compass."

3M said firefighting foam was used because it saves lives, noting that the military and other customers continued using it even after 3M stopped selling it.

"In any event, we believe these claims against 3M lack merit," 3M said in a statement. "3M sold these products with instructions regarding their safe use and disposal."

In other lawsuits, the historical ties to 3M are more direct. 3M also manufactured PFCs in Decatur, Ala., near the Tennessee River, and legally dumped them in a landfill. Now, several downstream communities face millions of dollars in water filtration costs, and residents worry about health effects after drinking the contaminated water for decades. Half a dozen state and federal lawsuits have been filed against 3M and other companies.

Waterproofing blowback

Less clear are the implications of lawsuits that target some of the thousands of customers who used PFCs in making their own products.

Wolverine Worldwide, for one, used them to make waterproof Hush Puppies shoes at a tannery in Rockford, Mich. Recent testing found startlingly high levels of PFCs in nearby private wells in a well-to-do suburb north of Grand Rapids. Tests show some area residents have blood concentrations of 3,000 parts per billion, which could increase their risks for disease, said Aaron Phelps, an attorney who has sued Wolverine. He said one of his clients, a 2-year-old boy, has 400 parts per billion — 20 times the highest levels found in the U.S. population.

Wolverine, which also makes shoe brands such as Merrell and Saucony, has paid for bottled water and well testing and is participating in the ongoing investigation. Like 3M, Wolverine says there are no known health effects from routine exposure to PFCs, and no human study has found they cause illness.

It's an open question as to whether 3M could share the liability in cases like Wolverine's. Attorneys for 3M and other businesses said that as long as the company fulfilled its duty to warn customers of PFCs' environmental risks — which it did — it bears no liability.

Nonetheless, some have their sights on 3M as well.

"I don't see there is a big difference" between the two companies, said Sharon Almonrode, an attorney who filed a class-action suit against 3M and Wolverine. 3M "sold it and tested it and sat silent about it."

Next week, when attorneys for the state of Minnesota lay out decades worth of internal 3M documents to make that same case, the people in Washington County may finally get a chance to make up their own minds about what the company knew.

"I'm sure the people here with family members who died of cancer would be very curious to know," said Kathy Henke, who's watched the entire drama unfold since the well at her Lake Elmo home was capped more than a decade ago. "But I suppose it's a difficult thing to prove."

Josephine Marcotty • 612-673-7394