In a commentary accompanying an article on the history of epidemiology, David Ozonoff of the Veterans Administration and Boston University School of Public Health cites a recent proposal from EPA as a modern example of how epidemiology is disparaged in comparison to laboratory science. To support its view that chloroform only presents a danger as a carcinogen when its concentration in drinking water exceeds 300 parts per billion, EPA has had to favor toxicological data over conflicting epidemiological data. This issue is part of a larger debate over how and to what extent to protect the American public from disinfectants and byproducts of drinking water disinfection.

Ozonoff blames the proposal to establish a threshold for chloroform in drinking water on EPA's faulty conclusion that there must be cell proliferation before carcinogenesis. "Has EPA allowed itself to be convinced by industry toxicology arguments while giving epidemological data a backseat or no seat? Will studies suggesting that as many as 9300 bladder cancers per year may be caused by exposure to chlorinated surface water be seen as second-class science?" EPA also "conveniently ignored" a new paper by Melnick et al. from the National Institute of Environmental Health Sciences showing that cell proliferation is not "required" for chloroform to cause cancer.

"It seems that EPA, like the tobacco industry, when it doesn't like what epidemiology reveals, has taken advantage of epidemiologists' self-critical habit and exploited legitimate differences of opinion among scientists over technical issues to cast doubt on results it finds inconvenient."

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Contact: David Ozonoff, MD MPH
dozonoff@bu.edu
617-638-4620
Public Health Reports
1-Jul-1998