The U.S. Environmental Protection Agency wants the state to rid the river of sediment that contains industrial chemicals, particularly polychlorinated biphenyls.  PCBs are absorbed by fish and are suspected of causing cancer.

A General Electric Co. study released last month reports no significant increase in cancer deaths among plant workers in upstate New York exposed to PCBs on the job.

The study, however, emphasizes scientists' uncertainty about whether exposure to PCBs can be linked to cancer.

The Wisconsin Department of Natural Resources also released a report in March on the relationship between PCBs and cancer.

That study found cancer risks for people eating fish from the Fox River and its estuary at Lake Michigan's Green Bay.

The risk is more than 1,000 times greater than the federal government's acceptable risk level, the DNR says.

PCBs were produced by riverside paper mills in the 1950s, 1960s and 1970s in making carbonless copy paper.  The companies ceased using PCBs in the 1970s but the residues remain in the river silt.

The EPA wants the silt dredged along a 39-mile section of the river between Lake Winnebago to Green Bay. It may put the river on its Superfund cleanup list and sue the companies to help pay the expense.

The EPA and DNR have recently held public forums on PCB contamination of the Fox River in several cities.

While the EPA classifies PCBs as a known carcinogen in animals and a probable carcinogen in humans, research showing no cancer effect in humans has been flawed, said Dr. J. Milton Clark, senior health and science adviser at the EPA's Chicago office.

"We really don't have a strong enough handle on what causes cancer in anyone to be able to say definitively about many environmental exposures that they do or don't cause cancer," said Chuck Warzecha of the state Division of Health.  "But that's more a result of the difficulty in studying what causes cancer than it is convincing evidence that PCBs don't cause cancer."

At least one Green Bay resident has chosen to live by his own code.

Al Timmerman, 69, said it's clear to him PCBs pose a health threat. But Timmerman, who has fished the Fox River and the bay all of his life and eats his catch once or twice a month, said he isn't worried about his health.

"They've made enough studies already," Timmerman said.  "If they're going to clean up the river, they should clean it up."

General Electric's study, paid for by the company, tracked the medical histories of more than 7,075 employees who worked from 1946 to 1976.  Researchers found that cancer was the cause of death for 353 of the 1,195 workers who have died, compared to the national and regional average of 400 for a statistically similar group.

GE faces hundreds of millions of dollars in liability for Superfund-driven PCB cleanups of the Hudson River in New York and Massachusetts' Housatonic River.

The GE study also has little bearing on those exposed to Fox River PCBs, Clark said. That's because it examined workers who breathed PCBs in the air as opposed to eating contaminated fish, Clark said.

People who eat fish from the Fox River get a more toxic dose of the contaminant because the most toxic PCB compounds tend to accumulate in body fat and work their way up the food chain, Clark said.

"From a public health policy standpoint, it's difficult to ignore the studies out there that show a problem, and in the case of PCBs we have enough information to show that PCB exposures at the levels we're concerned about in the Fox River are a problem," Warzecha said.

"Once it's implicated, you almost have to consider it guilty until proven innocent," he said.  "So, while we do feel we have very strong evidence that shows it's guilty, it would take more than just a technicality to get it off -- to make us treat PCBs as if they're not a health-risk issue."