The concentrations of potentially dangerous chemicals in the blood of east metro residents exposed to 3M Co. pollution have fallen significantly since 2008, state health officials reported Wednesday.

It's the first glimmer of hope in the bitter, decade-old fight between 3M Co. and several St. Paul suburbs over contaminated drinking water, a battle that so far has cost the company $50 million in cleanup efforts.

"This is a major piece of good news," said Jessica Nelson, bio-monitoring program coordinator for the Minnesota Department of Health.

Health officials said concentrations of the three different PFCs -- compounds once used in some of 3M's most popular products that are increasingly being linked to cancer, high blood pressure and other health conditions -- declined by 13 to 26 percent in 164 residents of Oakdale, Cottage Grove and Lake Elmo as they began relying on alternative sources of drinking water.

It's an indication that all the residents in the area, exposed for decades to the chemicals through drinking water contaminated by 3M's operations, are also experiencing declines, health officials said.

"The efforts by 3M have had a positive impact on reducing on PFC exposure," said Bill Nelson, spokesman for 3M.

But the concentrations found in residents under study are still significantly higher than normal. For example, the blood level of PFOS, one of the three chemicals that is of greatest concern, was still nearly twice the average found in the general population -- 24.3 parts per billion versus 13.2. And for reasons that health officials could not explain, about 30 residents showed either increases in PFCs or no change.

The compounds, still widely used in consumer and industrial products, are chemicals not found in nature. Like mercury, they accumulate in human tissue, and it takes years for them to clear once exposure has ended.

West Virginia study

While Tuesday's results were encouraging, they came just one day after officials in West Virginia released results of a separate study suggesting that the chemical compounds may have serious health consequences when found in higher concentrations.

A scientific panel in West Virginia reported that there is a probable link between PFCs and high blood pressure and pre-eclampsia, a dangerous health condition caused by high blood pressure, in pregnant women. At the same time, they reported that they found no such link to birth defects, pre-term births, miscarriages or stillbirths.

The science panel, which for six years has been studying the health consequences of PFC contamination of groundwater, is part of the settlement of a class action lawsuit between DuPont Co. and residents near the company's Washington Works plant in West Virginia. The panel is expected to release further medical findings later next year.

Those residents were exposed to much higher concentrations of PFCs than those in the Twin Cities, and still have significantly higher levels in their blood.

Minnesota health officials declined to comment on the West Virginia report because, they said, it has not yet been published in a scientific journal or vetted by other scientists.

3M denies there are any known health consequences from environmental exposure to the chemicals.

But other recent studies have also raised questions about the health consequences in people with just average amounts of PFC in their blood. In September, researchers published a study on 4,500 people and found that those with exposure levels often found in the general population were more likely to suffer from chronic kidney disease.

DFL state Sen. Katie Sieben, who represents the area, said that even though the chemical levels in local residents have declined, the ongoing health studies are critically important. "We have to rely on the good work they are doing in West Virginia," she said. "That lawsuit settlement resulted in millions of dollars. Here in Minnesota we are scrounging for very few resources to do these kinds of things."

Minnesota health officials received funding and direction from the state Legislature to monitor the level of PFCs in local residents. But they are not doing any research on health impacts. And, except for a follow-up review of the 30 people who still have high levels in their blood, they have no more funding for further studies, they said.

Use ceased in 2002

3M created the compounds and used them for decades in Scotchgard and other industrial and consumer products, and legally disposed of contaminated waste at local dumps.

It voluntarily stopped using them in 2002, but they had leached from the dump sites into drinking water in nearby east metro communities. The company and the state agreed to a cleanup plan in 2007, but last year state Attorney General Lori Swanson filed suit against 3M over future costs, including contamination of the Mississippi River above Hastings. The Health Department has issued warnings to limit consumption of fish caught in that area of the river because they carry very high levels of PFCs.

Josephine Marcotty • 612-673-7394