A new study suggests the Environmental Protection Agency gave too much weight to questionable industry scientific interpretations when it set new ``safe'' levels for exposure to vinyl chloride monomer, which is used to make PVC.
The study, written by environmental scientists and published in a government scientific journal, accused EPA of following industry's lead in downplaying risks of brain, lung and other cancers when it decided in 2000 to reduce estimated risks from VC exposure tenfold.
An EPA spokeswoman said April 21 that agency officials had not seen the report until a reporter brought it to their attention, and that agency scientists still were studying it.
In crafting the new standard, EPA officials had argued that they focused on cancer of the liver because it is the most sensitive organ, and protecting it would protect people from other cancers. Industry groups have acknowledged a link between VC exposure and liver cancer among workers, but have argued that studies have not found conclusive links between VC and other types of cancer, a point echoed by EPA.
The study was published March 24 in the National Institutes of Health journal Environmental Health Perspectives and was written by scientists from the Natural Resources Defense Council and other groups. IT said EPA should have given more weight to several studies that found an ``excess risk of brain cancer'' among industry workers, even if the specific relationship with VC exposure is unclear.
``Downplaying risk to nonliver cancer sites leaves the public and exposed workers inadequately informed of the health threat posed by exposure to VC-containing products, processes and pollution,'' the study said.
It continued, suggesting that the EPA's stance could benefit industry in litigation brought by exposed VC industry workers: ``Downplaying of nonliver cancer risks by the EPA may also have important implications in litigation of compensation cases, as claims for cancers at sites other than the liver are vigorously disputed in the courts.''
The study said EPA's outside peer reviewers of its VC rules did not include any union or public interest groups, but at least seven of the 19 were industry employees or consultants.
Jennifer Beth Sass, an NRDC senior scientist and lead author of the study, said that in response to criticism about other studies, EPA has broadened membership on review boards. The new rules are working well, Sass said.
The EHP study said that four industry-sponsored reviews - in 1974, 1988, 1991 and 2000 - found an increased risk of brain cancer among workers, but several said it was not clear if occupational or other exposure to VC was at fault. A 1987 study from the International Agency for Research on Cancer said VC caused brain and lung tumors and other malignancies, the EHP study said.
The EHP study noted that in the case of the 1991 industry-sponsored study, the authors published another paper in 1993 saying that the excessive occurrence of brain cancer among industry workers ``was not likely related to the chemical.''
The EHP study quoted a Houston Chronicle story that said the 1991 data was published without permission from the industry and, according to the paper, ``touched off a months-long effort to persuade [the author] to recant.''
The Vinyl Institute in Arlington, Va., did not comment, but an industry Web site, aboutblue vinyl.org, said that since the link between VC and a rare form of liver cancer, angiosarcoma, first was identified in the 1970s, the government has boosted safety standards, industry has introduced new technology, and exposure has fallen dramatically.
Employees at vinyl plants no longer face elevated risk of liver cancer, and no new cases of angiosarcoma have been found among workers who started after the new rules were put in place in 1975, according to the industry Web site.
The study criticized EPA for first proposing - and then abandoning - a threefold protective factor to account for nonliver tumors.
Industry had opposed the higher standard, and it also complained about an EPA statement that there is ``suggestive epidemiological evidence that cancer of the brain, lung and lymphopoietic system are associated with exposure.'' Industry urged EPA to delete the statement from the final report, which EPA did, according to the EHP study.
