My written testimony is here.
My research shows that the Report on Carcinogens is not a high-quality scientific work product. There are two major reasons why.
First, although Congress might have wanted a scientific compendium of substances carcinogenic to humans it did not ask for this in scientific language. Instead, it asked for a list of substances "which either are known to be carcinogens or may reasonably be anticipated to be carcinogens." But this is highly subjective, legalistic language that is foreign to the disciplines of science: Science does not “know” or “reasonably anticipate” things. These are not scientific words. They are the words of lawyers.
Second, the NTP has implemented this language in highly nonscientific ways that maximize its flexibility to use (or reject) scientific information however it sees fit. Among other things, the NTP's criteria for listing do not include any minimum scientific standard of causality. The NTP deems a substance a "known" human carcinogen if, in its sole and unreviewable judgment, "There is sufficient evidence of carcinogenicity from studies in humans.*
There is another highly significant problem with the way the NTP produces the Report on Carcinogens. The law establishes a second condition that must be met before a substance is listed as a human carcinogen: "a significant number of persons residing in the United States [must be] exposed" to it. The NTP simply ignores this statutory requirement.
Fixing the Report on Carcinogens will require congressional action.
First, despite the extent to which NTP listings violate federal law by failing to satisfy the exposure requirement, it appears that no one has standing to challenge a listing in federal court.
Second, until Congress revises the law to clearly direct the NTP to produce a strictly scientific compendium of human carcinogens, the NTP will continue to produce policy determinations based on undisclosed criteria.
My testimony identifies six specific ways Congress can improve the scientific quality and public value of the Report on Carcinogens. Until these (or similar) reforms are made, the Report on Carcinogens will continue to be highly controversial and largely useless.