Chemical plant workers exposed to C8 face an increased risk of death from prostate cancer and stroke, according to a new industry study recently submitted to federal regulators.
Chemical plant workers exposed to C8 face an increased risk of death from prostate cancer and stroke, according to a new industry study recently submitted to federal regulators.
Researchers found the high incidence of deaths among 4,000 employees of 3M's facility in Cottage Grove, Minn., according to the study filed with the U.S. Environmental Protection Agency.
Exposed workers did not have an increased death risk when compared to the population of Minnesota as a whole, according to the study.
But when compared to plant workers with less or no exposure, "risk of death from prostate cancer and [stroke] was elevated for workers with higher estimated exposure," the study found.
Among workers estimated to have the highest exposures, twice as many prostate cancer deaths as expected statistically were found, the study said.
The findings appear to confirm the conclusions from a 1993 study that 3M later said was incorrect, and add to a growing body of scientific research that raises questions about C8's safety.
In West Virginia, DuPont for years used C8 to make Teflon and other products at its Washington Works plant just south of Parkersburg.
C8 is another name for ammonium perfluorooctanoate, or PFOA.
DuPont has settled several lawsuits over C8 pollution. One deal could eventually cost the company more than $300 million. Another was brought by federal regulators who alleged DuPont withheld key information about the chemical's health effects.
Publicly, DuPont continues to argue that "there are no human health effects known to be caused by" the chemical.
Dan Turner, a DuPont spokesman, said Tuesday the company has not seen the new 3M study and therefore would not comment.
Bruce Alexander, a University of Minnesota scientist who produced the 3M study, did not return a phone call.
Bill Nelson, a 3M media spokesman, said the company's top epidemiologist, Geary Olsen, said it would not be appropriate for him to comment on the new study because it has not been peer-reviewed or published in a scientific journal.
But Nelson said 3M wanted to "offer some perspective" on the study because it is now "out in the public domain."
"What 3M has said is that exposure to PFOA at the levels in the environment does not cause adverse health effects," Nelson said. "This paper does not contradict that statement."
Chemical plant workers exposed to C8 face an increased risk of death from prostate cancer and stroke, according to a new industry study recently submitted to federal regulators.
Researchers found the high incidence of deaths among 4,000 employees of 3M's facility in Cottage Grove, Minn., according to the study filed with the U.S. Environmental Protection Agency.
Exposed workers did not have an increased death risk when compared to the population of Minnesota as a whole, according to the study.
But when compared to plant workers with less or no exposure, "risk of death from prostate cancer and [stroke] was elevated for workers with higher estimated exposure," the study found.
Among workers estimated to have the highest exposures, twice as many prostate cancer deaths as expected statistically were found, the study said.
The findings appear to confirm the conclusions from a 1993 study that 3M later said was incorrect, and add to a growing body of scientific research that raises questions about C8's safety.
In West Virginia, DuPont for years used C8 to make Teflon and other products at its Washington Works plant just south of Parkersburg.
C8 is another name for ammonium perfluorooctanoate, or PFOA.
DuPont has settled several lawsuits over C8 pollution. One deal could eventually cost the company more than $300 million. Another was brought by federal regulators who alleged DuPont withheld key information about the chemical's health effects.
Publicly, DuPont continues to argue that "there are no human health effects known to be caused by" the chemical.
Dan Turner, a DuPont spokesman, said Tuesday the company has not seen the new 3M study and therefore would not comment.
Bruce Alexander, a University of Minnesota scientist who produced the 3M study, did not return a phone call.
Bill Nelson, a 3M media spokesman, said the company's top epidemiologist, Geary Olsen, said it would not be appropriate for him to comment on the new study because it has not been peer-reviewed or published in a scientific journal.
But Nelson said 3M wanted to "offer some perspective" on the study because it is now "out in the public domain."
"What 3M has said is that exposure to PFOA at the levels in the environment does not cause adverse health effects," Nelson said. "This paper does not contradict that statement."
The new 3M study was dated Aug. 22, 2007, but was not filed in an EPA C8-related public docket until Feb. 20, 2008.
Nelson said 3M also filed the document in a more general toxic chemical information system on Sept. 27, 2007, to meet a 30-day legal reporting deadline.
For more than 50 years, 3M produced C8 and related chemicals used in popular products such as Scotchgard and Teflon.
In May 2000, 3M announced it was "phasing out" production of these chemicals.
3M officials took that step after learning of a 1999 DuPont study in which monkeys exposed to C8 had to be killed because they were suffering from such severe health effects, according to government records. 3M also moved to phase out C8 production after being warned the EPA planned to begin more strictly regulating such chemicals.
Researchers are finding that people around the world have C8 in their blood. The levels may generally be small, but it is unclear whether these amounts are dangerous. Among the recent findings, a Johns Hopkins study reported that babies exposed to low levels of C8 in the womb were born slightly smaller than other infants.
The new 3M study did not detail levels of exposure or amounts in worker blood. Generally, worker exposure would be at far higher levels than the general public.
In 1993, a 3M study found that workers in C8 production were three times as likely to die of prostate cancer as other plant employees. In 2001, 3M said a follow-up study found no such problems.
But the EPA, in a draft risk assessment issued in 2005, said the follow-up study changed the way C8 exposure was categorized so that the two studies could not be accurately compared.
Last year's 3M report cautioned that death studies have "severe limitations [that] should be considered."
For example, the report said, some misclassification of worker exposures "is likely."
"For example, maintenance and other mobile workers that routinely entered the definite PFOA exposure departments and work areas, but may have not been classified in the definite exposure subgroup," the report said. "On the other hand, a few workers assigned to the definite exposure subgroup may not have spent much time in those departments or work areas."
The study concluded that while similar findings have been previously reported, "the current study has a longer follow-up period, therefore more deaths, increasing the power of the study."
To contact staff writer Ken Ward Jr., use e-mail or call 348-1702.
