Perhaps research seems credible when it gets published in a journal. But your readers should know that the claims in ``Vinyl Chloride: A Case Study of Data Suppression and Misrepresentation,'' published in Environmental Health Perspectives and reported in Plastics News (``Study criticizes EPA for hiking `safe' level of exposure to VC,'' April 25, Page 4) were way off the mark.
The authors of the Environmental Health Perspectives article assert that there is a ``scientific consensus'' that vinyl chloride can cause multiple forms of cancer in humans and experimental animals, but only three of the 21 articles they reference were published in the past 15 years. They fail to mention or seriously discuss seven articles published in scientific journals since 1997 that reach the opposite conclusion. These and other recent, peer-reviewed studies and reviews fully support the Environmental Protection Agency's conclusion that the association between vinyl chloride and cancers other than liver ``is weak and any estimated increase in mortality from cancer at these sites is likely to be less than for liver cancer.''
One of the authors of these recent studies is the Chief of the Occupational Studies Section of the National Cancer Institute, who states that epidemiological evidence shows a strong exposure-response relationship for angiosarcoma of the liver but not for other types of cancer.
A more recent review reaches the same conclusion, stating that exposure to vinyl chloride in the workplace ``has not been conclusively causally linked to any adverse health outcome, with the exception of angiosarcoma of the liver.'' Even more recently: ``The aggregate data are reassuring in excluding any excess risk of death from lung, laryngeal, soft tissue sarcoma, brain and lymphoid neoplasms, as well as cirrhosis.''
At one time, there was an apparent association between vinyl chloride and brain cancer excesses, but these were found to be related to a single facility. A number of investigations since then, most notably by scientists at the National Institute of Occupational Safety and Health, have shown that the excess brain cancers observed at the facility were not related to vinyl chloride exposure.
The Environmental Health Perspectives article also made inaccurate and unsupported allegations about the integrity of EPA scientists and the peer-review process used by the EPA.
While the EPA placed some reliance on industry-sponsored papers, the agency - which, by the way, met the scientific standards of peer review - relied for the most part on studies by scientists affiliated with prestigious, government-supported organizations such as NCI and NIOSH, cited above, the International Agency for Research on Cancer, and others.
We were genuinely surprised that such a one-sided, far-from-accurate review made it through the peer-review process of the government publication whose stated mission is to publish ``balanced'' and ``objective'' information.
Courtney M. Price
American Chemistry Council