Fluoride Action Network

Minnesota: MPCA staff at odds on stopping spread of contamination from 3M plant

Source: Minnesota Public Radio | April 2nd, 2007 | By Lorna Benson
Industry type: Perfluorinated chemicals

The Minnesota Pollution Control Agency’s plan for cleaning up PFCs from the 3M plant in Cottage Grove is under question. As a result of MPR’s investigation, the MPCA commissioner says he will bring in an independent third party to review his agency’s proposal to stop the spread of PFC contamination.

St. Paul, Minn. — Five years after 3M stopped making PFCs, the company’s plant in Cottage Grove is still releasing those contaminants into the Mississippi River.

Despite efforts to significantly reduce PFC discharges, that plant and a nearby 3M landfill in Woodbury are the main sources of the chemicals in the river, according to the state. As a result, the MPCA and 3M plan to begin a major cleanup project at the plant this summer.

But one MPCA engineer who works on the project says his agency’s agreement with 3M doesn’t go far enough. He says the plan won’t stop the contamination from reaching the Mississippi.


Over the past 50 years, 3M has disposed of industrial waste from its PFC operation in many places — at landfills in the east metro, and at eight or nine spots at its own production plant in Cottage Grove.

The facility, perched above the trees on the edge of the Mississippi River, is the biggest source of PFC contamination in the state.

A pipe carrying PFC-laden water from the Woodbury landfill discharges, unfiltered, into the river at this site. 3M also releases processed wastewater from the plant, containing additional PFCs, into the river. Those are just the measurable PFC discharges.

“The groundwater underneath the plant is highly contaminated in some areas,” said Don Kriens, an engineer with the Minnesota Pollution Control Agency. “That moves toward the river, discharges into the river — so that comprises another source of PFCs to the river.”

Kriens, who oversees 3M’s wastewater permit for the plant site, estimates that each year, between 1,000 and 2,000 pounds of PFCs are discharged into the river, from 3M cooling water and the water pumped down from the Woodbury landfill.

That’s a fraction of the PFCs the company discharged five years ago, before 3M phased out some of the chemicals. But the amounts are still significant enough to concern MPCA officials.

Kriens says it’s hard to estimate the amount of PFCs that seep into the river from the groundwater each year. All he has to go on are the groundwater readings from under the plant.

“Those levels are quite high. Some of them are — the PFOA — 350 parts per billion. And some of the other ones are even higher,” said Kriens. “So that is a concern, and that has to be dealt with in some way.”

3M stopped making PFOA and another perfluorochemical called PFOS in 2002, after finding the chemicals had spread throughout the world and were in the blood of 3M workers. Lab studies have shown the chemicals can be toxic to lab animals when given in high doses.


The suspected source of much of the PFC groundwater contamination at the plant is an old dump site located on the edge of the property, along a bluff which rises about 100 feet above the Mississippi river.

The MPCA says it is so concerned about this dump site that it has asked 3M to fast-track its cleanup plan for the bluff. The company has proposed capping the site with a six-acre geo-membrane cover, made of waterproof plastic or rubber. The idea is to block rainfall, and at the same time, slow the movement of contaminated groundwater.

MPCA remediation officials have signed off on the plan. But MPCA engineer Don Kriens openly opposes his colleagues’ decision.

“In my opinion, it won’t stop overall the flow of this [PFCs] into the river over time,” Kriens said. “It still ultimately can get there, because there’s nothing to stop it underneath from flowing from [surface] water, groundwater and so on over a longer period.”

Instead, Kriens thinks the heavily contaminated dumps should be dug out of the ground and removed from the site.

Kriens has worked at MPCA for more than 25 years and is well respected for his technical expertise. But his views have pitted him against some of his colleagues.

Another MPCA scientist, Michael Kanner, is overseeing the remediation process at the 3M plant. He says to do what Kriens suggests on the sandy bluff would be dangerous.

“You’ve got this contamination down to 70 feet or more. And it’s sand here. So the ability to actually clean all of that up without destroying the bluff — you’d have to destroy that whole feature is what it seems to us,” said Kanner. “And you’d also at the same time endanger the workers. You’ve got a major railroad line here, you’ve got the river here. We don’t want to add to that, we want to stabilize what the situation is there.”

Kanner told MPR News that caps have been very effective in other situations. He insisted the concept should work equally well along a river bluff.

“We have the same concern about the river as everybody else does, that we want to protect the river, and we’re concerned about the impaired waters and so on. Our belief is that this interim cover is going to actually work,” said Kanner. “We have a lot of experience with this. You can ask ‘what ifs’ all the time, but we think it’s going to work. There’s no reason why it shouldn’t.”

Although the state has used geo-membrane caps on other landfill sites, the agency acknowledges it has not used them to control PFCs on bluff land.

When informed of the debate over the cap, 3M’s Director of Health Safety Michael Santoro said as far as he knew, the MPCA was fine with the company’s plan for the site.

Santoro said as an extra measure, 3M will install a barrier well near the cap, to pull contaminated water out of the bluff and filter it before releasing it into the river.

“I don’t remember the detail on that, but I know it’s at least one, maybe a couple [wells] that will be sufficient to capture any migration from that location,” said Santoro.


A few days after Minnesota Public Radio’s interviews with 3M and MPCA staff, the agency’s Commissioner Brad Moore told MPR the dispute has convinced him to bring in a third party to review the agency’s remediation plans for 3M.

“Given that particular debate, it also underscores the uncertainty in some of the science,” said Moore. “I want a review of that because I think the public needs to be confident, and the Legislature, and frankly myself, in terms of the appropriate direction to go from here.”

During Brad Moore’s relatively short time at the agency, he says he has tried to make the MPCA’s dealings on PFCs transparent. Moore replaced Sheryl Corrigan, who left the MPCA in August 2006.

Corrigan, a former 3M manager, had been criticized for not doing enough to investigate PFCs on her watch. Also during her tenure, MPCA scientist Fardin Oliaei, the agency’s lead researcher into PFCs, left the agency. She says she was forced out, after arguing publicly that the MPCA should expand its PFC investigation.

In addition to the independent review of the 3M plant cleanup plan, Moore declared last month that his agency intends to classify the release of two PFC substances, PFOA and PFOS, as hazardous.

Moore says the designation means the MPCA will have more legal tools to persuade 3M to clean up PFC contamination at three locations, including the plant.

“We’ve been very pleased with the cooperation we’ve received from 3M to date. But it’s clear that this issue is growing, and these chemicals and compounds are going to be in the water for a long, long period of time and the remediations are going to take a long period of time,” said Moore.

Tissue samples show that fish from the Mississippi River near the 3M plant contain some of the highest levels of PFCs found anywhere in the world. The discovery prompted the Health Department to issue a fish consumption advisory last year for that stretch of the river from St. Paul to Hastings.

Since that time, the MPCA has sampled even more fish from as far downriver as Winona. Those results are expected to be released this month.