VIENNA - The C8 Science Panel announced Monday it found a probable link between exposure to C8 and both testicular and kidney cancer.
The panel was unable to find any link between exposure to ammonium perfluorooctanoate, also known as PFOA or C8, and 19 other cancers, including thyroid cancer or melanoma, "for which limited but insufficient evidence to support an association was found." The epidemiologists that make up the three-member panel also found no link between C8 exposure and adult onset Type II diabetes.
The announcements were made Monday during a press conference. This was the second phase of the probable link assessments; the first was in December and involved reproduction.
Article Photos
Dr. Kyle Steenland, one of the members of the three-member C8 Science Panel, outlines the probable-link findings during a press conference Monday. The science panel announced it found a probable link between exposure to C8 and testicular cancer and kidney cancer. (Photo by Pamela Brust)
The final reports are expected at the end of July.
The 2005 settlement in the class-action lawsuit filed on behalf of residents in six water districts against DuPont Washington Works defines "probable link" as "whether it is more likely than not that PFOA exposure among class members is linked to a human disease."
The six water districts were Little Hocking, Belpre, Lubeck, Tuppers Plains, Pomeroy and Mason County. The suit stemmed from DuPont's discharge of C8, which is used in the manufacture of Teflon and other non-stick products, into local drinking water supplies. As part of the settlement, the mutually agreed upon science panel was named and charged with independently and comprehensively evaluating all available scientific data relating to PFOA to determine whether there is a link between C8 exposure and serious human disease.
For Joe Kiger, one of the original plaintiffs in the civil action, Monday's announcement validates what he and others have believed all along.
"This is what we've been trying to find out for the past 11 years. We assumed there was something that wasn't right. Too many people in the area were sick, and I think the borderline cases, like the prostate cancer, I wanted to know if they could come back and recheck, re-evaluate what's going on with that and the C8. We weren't out to get DuPont, but the community now has to see that they have to be accountable for their actions. They knew this stuff was bad, yet they kept putting it out there. Now, it's time to fess up. We don't know what's coming up in July. We'll have to wait and see what they have to say then, " Kiger said.
In a written statement released following the press conference, DuPont said "a probable link report does not mean that the science panel has concluded that PFOA exposure has caused or will cause any human disease among the class members as a whole, including the Washington Works employees or any individual."
"Consistent with our core values of health, safety and environmental stewardship and before any reports from the science panel, DuPont took actions to minimize PFOA exposure. For decades, DuPont has had industrial hygiene measures in place to minimize worker exposures to PFOA. Data shows that these measures are effective. DuPont has reduced total PFOA emissions by more than 98 percent in our global manufacturing operations since 2000. We also have developed and commercialized new technologies to make fluoropolymers without using PFOA, and to make surface protection products that cannot break down to PFOA in the environment. Regulatory authorities around the world have affirmed that these products are safe for their intended uses."
"DuPont will continue to meet its obligations under the West Virginia litigation. DuPont will evaluate additional information from the science panel as part of our long-standing commitment to the safety of our employees and customers and to responsible environmental and product stewardship," according to the statement released Monday through Robin Ollis-Stemple, external affairs with DuPont Washington Works.
During Monday's press conference, the panelists outlined their findings after review of the health project participants, published studies conducted by others, published and unpublished work done by the science panel, studies of DuPont workers and related followup studies and medical records.
"We concluded there is no probable link between PFOA (C8) and either thyroid cancer or melanoma, for which limited but insufficient evidence to support an association was found. We also concluded that there are no probable links with any of the other cancers considered including liver, pancreas or breast cancers," according to the science panel's report.
"For testicular cancer, there is evidence of a positive trend in risk across exposure groups, in some analyses, with the highest exposure group in both the internal analyses of the cohort study and the geographical cancer study showing estimated relative risks ranging from 3 to over 6 comparing the highest to lowest exposure groups. On the other hand there was little or no evidence of increasing risk in analyses from the same cohort compared with the U.S. population, and in the period after 2005, there were no new cases compared to about five expected. The high exposure group, where the higher risk was observed, comprises only six cases therefore there remains some uncertainty. The science panel notes that there is experimental evidence of testis cancer being increased in exposed animals. The science panel considers observed excesses to indicate a probable link between PFOA and testicular cancer," according to the reports issued by the science panel.
The cohort study refers to the study of more than 28,000 community residents and 4,000 DuPont workers interviewed in 2009 and 2011 including taking of their medical histories.
"One needs to remember this (testicular cancer) is a relatively rare disease so it was based on a small number of cases, but nevertheless it was statistically significant," said Dr. Tony Fletcher, one of the members of the science panel.
For kidney cancer, the worker mortality study conducted by the science panel showed a higher risk in the most highly exposed group compared to lower exposure groups among the workforce, but the risks were not elevated compared to the U.S. population. When the 10 years of exposure prior to diagnosis was excluded, the association was less evident. No association was seen in the prospective analysis of cohort data, although the latter is limited by small numbers. In the geographic study some results suggested an increasing risk of kidney cancer with increasing exposure and others did not. The science panel considers that the excesses observed indicate a probable link between PFOA and kidney cancer," according to the panel's report.
"Prostate cancer showed a weak signal, but was not confirmed in the geographic analysis," Fletcher said.
For thyroid cancer, the science panel reported there is no animal evidence nor geographical study of cancer indicating positive trends linking PFOA to thyroid cancer.
The science panel members noted the incidents of Type II adult onset diabetes were much higher.
"Out of 4,800 study subjects, a quarter of the population reported Type II adult onset diabetes. We looked at Type I separately and we will have that report in late July. There was no positive trend of diabetes in the categories, which for us provided fairly strong evidence there was no effect," Dr. Kyle Steenland, a member of the panel, said.
The science panel is expected to file its final reports by the end of July. In December 2011, the panel released its first set of reports focusing on reproductive outcomes only. At that time, the panel announced it had found a probable link between PFOA exposure and pregnancy-induced hypertension, including preeclampsia.
With PFOA now linked to serious human disease, DuPont's class action agreement requires it to pay up to an additional $235 million to fund a medical monitoring program. The program will help detect the onset of PFOA-linked diseases among the approximately 70,000-80,000 residents who are class members as defined in the settlement agreement.
For more information on the science panel studies and findings, go to its website at www.c8sciencepanel.org.
