3M Co. is seeking to postpone a long-awaited trial, set to begin next week, over groundwater contamination in Washington County, citing a "game-changing" Health Department report that found no link between public health effects and the chemical it produced.

The state report, released Wednesday, repeated the agency's earlier conclusions that residents experienced no higher rates of cancer, premature births or low birth weight babies in communities where drinking water was contaminated by a class of 3M chemicals known as PFCs.

The report clashed with the findings of an expert witness hired by Attorney General Lori Swanson, who is suing 3M over alleged damage to Minnesota natural resources.

Hennepin County Judge Kevin Burke has scheduled a hearing Friday afternoon to consider 3M's motion and other pending legal questions in the case, which is set for trial starting Feb. 13.

The clashing legal documents filed by 3M and Swanson provide a glimpse into how the fight over science is likely to drive the most significant environmental lawsuit Minnesota has seen in years.

At issue is the legacy of PFCs, the nonstick chemicals used for decades in dozens of consumer and industrial products, that 3M dumped legally in Washington County landfills starting in the 1950s.

3M, one of the state's most highly regarded Fortune 500 companies, says it has always protected the health of its workers and local communities, and that there is no evidence that PFCs cause harm at the concentrations found in the environment.

Swanson's argument

Swanson argues that for years the company dumped PFCs knowing that they could cause cancer and environmental damage.

Her expert witness, David Sunding, found significantly higher rates of cancer and premature births in some east metro communities, such as Oakdale, and his report caused widespread anxiety in the affected suburbs when it was released last fall.

Now the state's own health analysis has added an unexpected complication, one that 3M is trying to use to its advantage.

3M attorneys said the Health Department's findings, which echo those it made public in 2007 and 2015, "destroy" Swanson's argument that human health effects from 3M waste contribute to up to $5 billion in damage she is claiming.

They described the Health Department report as a "game changing" development in the litigation.

Swanson's attorneys responded that the analysis by Sunding, a natural resources economist, is more sophisticated because it used targeted variables such as race, education and income that make his results more precise.

The Health Department's report, they said, relies on "rudimentary" methods and is nothing more than "a retread" of its earlier results. The Health Department conducted its update in response to public concern in the wake of Sunding's November report, and state officials said it used statistical methods widely used in public health research.

The Health Department report was completed and rather abruptly released just days before the trial at the urging of Gov. Mark Dayton — the first time he's been known to weigh in on an issue related to the lawsuit.

Dayton's office said Thursday that the governor thought the information could be important to the attorney general's office and the public.

But the circumstances caused some consternation at the Health Department, according to an internal e-mail obtained by the Star Tribune.

In it, one of the lead epidemiologists, Alan Bender, expresses frustration at the rush to complete the report and whether specifics such as "the inclusion of race" are required to accurately reflect cancer rates.

'Much at stake'

Bender concluded that "nothing changes our conclusions" that there are no unusual rates of adverse birth outcomes or cancer cases in the affected communities. But he wrote that the department's scientists were working furiously to complete a report that they can defend in all forums, "public and scientific."

"We have much at stake here," he concluded. Late Wednesday, the Health Department said concerns raised in the e-mail were addressed before it released the report this week — and reflected only the explanations and presentations in the report, not the data and the final conclusions.

Still, the conflict was sufficient to generate concern at the two state agencies.

Life behaviors 'matter'

Last week the Health Department scientists presented their findings at a meeting with Swanson's attorneys, and Sunding flew in from California to attend.

In an interview Thursday, Sunding said the two reports use essentially the same data on age, gender, health and residents' location.

The differences, he said, primarily concern the findings on cancer and are related to variables such as race and income that he factored into his analysis.

"All correlate with lifestyle behaviors that have to do with cancer rates," he said. "They matter a lot."

Josephine Marcotty • 612-673-7394