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New limits for chemical consumption a relief for some, not all

The Minnesota Department of Health last week released a new health-based exposure limit for a chemical formerly produced by 3M found in Cottage Grove's municipal drinking water, upping by seven times the amount that can be consumed safely over a lifetime.

Health officials say the amount of perfluorobutanoic acid (PFBA) in south Washington County municipal water supplies are well below the new limit of 7 parts per billion, findings Cottage Grove Mayor Sandy Shiely called "a huge relief."

The original exposure limit of 1 part per billion was "based as much on what we didn't know as what we did know," said the health department's James Kelly. "It was a very cautious number based on incomplete info."

Three studies conducted over the past year were used to assign the new health value that department of health officials said denotes how much of the chemical poses no health risk, even if consumed daily over a lifetime by people as young as infants.

The studies showed PFBA is less toxic than initially thought, passing through the body in a matter of days. On the other hand, other perfluorochemicals (PFCs) found in well water in parts of Washington County, including Cottage Grove, take years to exit the body.

"The biggest difference (between PFBA and the other PFCs present in area water) is its half-life in the human body," Kelly said. "That's another key piece of info that we didn't have a year ago."

Widespread PFBA contamination was found in late-2006 in south Washington County, the result of chemicals seeping into groundwater from 3M landfill sites, officials believe.

3M -- which contends water tainted with PFBA, perfluorooctane sulfonate (PFOS) or perfuorooctanoic acid (PFOA) is unequivocally safe to drink -- funded the studies, which cost hundreds of thousands of dollars.

That led to questions from some at community meetings last month that the company would influence the outcome.

It didn't happen, Kelly said; numerous independent scientists collaborated on the studies, ensuring the legitimacy of the results.

"They funded the tests and I think that's appropriate -- this kind of testing is extremely expensive and time-consuming," he said.

The new health-based value should help assuage the fears of residents relying on municipal water, Kelly and Shiely said. But area legislators Sen. Katie Sieben, DFL -- Cottage Grove, and Rep. Karla Bigham, DFL --Cottage Grove, both said in a release last week more needs to be done to fully examine the effects of the 3M-produced contaminants.

"I will continue to press the Minnesota Department of Health to study these chemicals," Sieben said. "Residents expect and deserve clean water."

Jon Avise can be reached at