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Oakdale residents who drank water polluted with toxic "forever chemicals" experienced elevated rates of infertility, premature births and low birthweight babies due to the contaminants, according to a multiyear review of health records.

The authors of the peer-reviewed research, published in April in the journal Environmental Health, say it's the first to establish a causal link between the chemicals and reproductive impacts. It could be evidence in scores of lawsuits attempting to hold manufacturers, such as Maplewood-based 3M Co. and DuPont, accountable for alleged health and environmental damages.

Philippe Grandjean, a leading researcher on the chemicals at Harvard University, discussed the paper in a webinar Wednesday, explaining that the Washington County suburb became a "natural experiment." That's because there were significant measurable differences in the health outcomes before and after Oakdale installed a filtration facility in 2006 to remove the per- and polyfluoroalkyl substances (PFAS) from the municipal water supply.

Causation is crucial not only to advance scientific understanding of how these contaminants affect human health.

"I think it will be used in litigation that has been filed and is going to be filed, not just here but in other countries as well," said former Minnesota Attorney General Lori Swanson.

Swanson successfully sued 3M, leading to the state's historic $850 million settlement with the manufacturer in 2018 for environmental damages.

PFAS are a large family of chemicals, some of which have been linked to health problems, including diseases such as cancer. Called "forever chemicals" because they don't easily break down, the chemicals shed oil and water and have been used in wide variety of industrial and consumer products, such as water-repellent fabrics.

3M, which invented the chemicals, manufactured two of the original substances for years at its plant in Cottage Grove, and dumped contaminated material in four landfills around Washington County, leading to severe groundwater and drinking water contamination.

On Wednesday, Grandjean said lower birthweights indicate some metabolic interferences during a time the body is programming its organs and that more work needs to be done to understand what is happening.

"It's not the birthweight as such, it's the implications," Grandjean said. "This is a red light. This is like a signal: 'Hey, there's something bad going on here.' 

"We're looking at the tip of an iceberg here."

Specifically, the new findings show that babies in Oakdale were 35% more likely to weigh less than 2,500 grams, or 5½ pounds, at birth, and nearly 45% more likely to be born before 32 weeks, than those in communities where the water wasn't contaminated. The general fertility rate was 15 to 25% lower.

The differences lessened after the water filtration was installed at the end of 2006.

The new research is based on similar work done earlier by David Sunding, a natural resources economist at the University of California, Berkeley. The analysis was part of Sunding's testimony as an expert witness for Swanson when she sued 3M.

"I was always confident in the results — they practically jumped off the screen from the first time we ran the model — and I swore so in my testimony for the [attorney general]," Sunding said in an interview. "That said, peer review is the acid test for academics, and now the paper has survived that and been published in a good public health journal."

Different conclusions

The Minnesota Department of Health stands by its own earlier conclusions on the matter.

After Sunding's first analysis was made public during the trial in 2018, the agency published its own analysis of birth outcomes in Washington County — drawing very different conclusions. Using different methods, it concluded there wasn't any unusual increase in low birthweights or premature births there.

Jessie Shmool, the Department of Health epidemiologist who led the state's analysis, said the state used more detailed data and more ZIP codes over more time points. She said she reviewed the new peer-reviewed article, and the researchers used the same data and methods as Sunding's earlier study, and the state wouldn't change its conclusions.

"We want to make sure that when we are saying something is a smoking gun, a causal thing, that it really stacks up," Shmool said.

She said the agency continues to work with east metro communities dealing with the contamination. The state's health-based limits for PFAS in drinking water are generally the lowest in the country, she said, and directly protective of fetuses.

Swanson accused the Health Department of a "whitewash" in 2018, and she said the new study is "very much a rebuke about what the Department of Health said about the impacts on babies and children."

3M issued a statement Wednesday saying the study does not establish a causal relationship between PFAS and birthweight.

Company spokesman Sean Lynch faulted the study for not taking into account individual exposures to PFAS, including perfluorooctanoic acid (PFOA), and other factors that could affect birthweights, such as smoking. A recent analysis published in the journal "Epidemiology" of two dozen studies "showed little or no association of PFOA with birthweight," he noted.

Jennifer Bjorhus • 612-673-4683