Workers who were exposed to a chemical called PFOA (perfluorooctanoic acid) at 3M’s factory in Cottage Grove had very increased rates of developing strokes and cancer and eventually dying compared to other workers at the plant, University of Minnesota researcher Bruce Alexander wrote in a study made last year.

PFOA was used in the manufacture of nonstick coatings and other products up until 2002. 3M manufactured PFOA from 1947 to 2000 at its Cottage Grove plant. PFOA has been shown to cause liver, pancreatic, and testicular cancer in laboratory animals in time.

The study, which included nearly 4,000 employees, who worked from 1943 to 1997, divided the workers into three groups: those with definite exposure to PFOA, those with probable exposure to the chemical and those who were not exposed. The results showed that the group with the highest exposure to the chemical had twice as many deaths from prostate cancer and stroke than the group who were not exposed. However, the results were contradictory, as the same employees did not have a higher risk than Minnesotans in general.

“We spent a lot of time trying to figure out if we’d missed something, done something wrong. It was just very confusing results. And in the end the results were there and they’re not that clear. And so we just have to move forward and think of better ways to look at it,” epidemiologist Alexander said quoted by the Minnesota Public Radio.

This conclusion made the company state that the results reinforce its belief that PFOA does not cause people to get ill.

"The point being is that here in 2008, prostate cancer is not a leading cause of death. And so it may not be a good marker. And so the next step is to look at the incidences of prostate cancer and determine is there anything going on there," said Bill Nelson, 3M spokesperson.

The study, funded by 3M, will be reviewed by the Minnesota Department of Health.