Redefining carcinogenicity

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Every two years, the National Toxicology Program (NTP) releases its government-mandated Report on Carcinogens, which lists agents, substances, mixtures, and exposures in the environment that may increase a person s risk of cancer. Just this month, however, the NTP announced that they have revised the procedures the program uses for identifying carcinogens; but as a new analysis by the Competitive Enterprise Institute (CEI) points out, the program still needs a major overhaul.

As Dr. Richard Belzer, author of the CEI report states, Statutory ambiguity enables the NTP to reserve for itself the discretion to consider whatever information it wants, to exclude whatever information it wants, and to evaluate that information in accordance with whatever ad hoc criteria it wants to apply. Instead, the NTP should rely on a strictly scientific weight-of-evidence scheme, Dr. Belzer says, that takes into consideration important differences in potency across substances and probable exposure levels.

Indeed, if the NTP ignores these important parameters, says ACSH s Dr. Ruth Kava, then they can never identify a substance s actual effect on cancer risk in the real world.

Listing something as cancer-causing can be meaningless or meaningful, adds ACSH's Dr. Josh Bloom, but you can t tell which is which based on the current NTP standards, since they lack exposure data.