In a victory for 3M Co., a judge ruled today that 67,700 residents of Washington County will not be considered as a a single group in a lawsuit against the company for damages allegedly suffered because of chemicals detected in their water.

The ruling The ruling by Washington County District Judge Mary Hannon denied class certification for the residents - which will greatly help 3M as it defends one of the biggest environmental lawsuits in state history.

"3M is pleased. The entire ruling is a victory," said company spokesman Bill Nelson.

Six county residents brought the lawsuit, which has been joined by another 1,000 people, according to the plaintiffs' lawyers.

Hannon's ruling means anyone wishing to sue the company for similar damages will have to do so in a separate legal action.

The chemicals detected in trace amounts are PFCs, or perfluorochemicals, made by 3M for such products as Teflon and Scotchgard stain repellant. They were legally disposed of by 3M in landfills in Washington County. In 2004, the chemicals were discovered in drinking water in Lake Elmo and Oakdale.

The discovery of a related chemical in drinking water in communities including Cottage Grove and Woodbury was announced in January.

Mega-doses of PFCs have caused cancer and other problems in rats. But state officials said they pose no short-term health risk to humans because they are in such minute amounts in the drinking water.

PFCs in water are measured in parts per billion - the equivalent of one second in 32 years. It is calculated that a Woodbury resident would have to drink 500,000 glasses of water a day to match the dose at which rats begin to show an effect. Longer-term studies of the effects of PFCs are under way.

The stakes in the case are potentially huge. If the case had gone to trial with the larger group certified as a class, no one could have predicted the amount of a potential settlement. But an Ohio case involving the same chemicals ended in 2005 with a settlement of $300 million.

In that case, the DuPont Company agreed to pay to remove chemicals from drinking water and monitor the health of water-drinking residents in the future. It did not pay for any alleged damages done to the water-drinkers.

Attorneys for the plaintiffs wouldn't comment Tuesday, but said in a written statement that their case would go forward without class certification.

But others suing 3M - or who may want to in the future - were disappointed.

"I think this is a setback," said Jon Archer, who noticed many neighborhood children with developmental disabilities when he lived in Oakdale.

He has blamed the water. "It shows you how big powerful attorneys manipulate the system," Archer said of today's ruling.

Mike Bradley, a Woodbury attorney with thyroid cancer, could have joined the lawsuit if the certification was allowed. Now, if he wants to sue 3M, he will have to take separate legal action.

"It's tremendously frustrating," said Bradley. "I am not sure what the judge was thinking. I am really concerned that corporate interests not be placed above families and children."