Congressional Hearings Question National Toxicology Program’s Science

Today, the House Science, Space, and Technology Committee and House Small Business Committee held a joint hearing on the National Toxicology Program’s (NTP) Report on Carcinogens. The hearing addressed the NTP process for classifying chemicals as carcinogens and its impact on small businesses. In particular, witnesses focused on NTP’s decision to classifying styrene as “reasonably anticipated to be a human carcinogen.”

The NTP issues this report every couple of years to assess whether to list industrial chemicals as “carcinogens.” Although NTP does not issue regulations, mere listing can have significant market impacts, hurting businesses — small and large — that make and use the chemicals.  Listings are also used by other agencies to justify regulations. Such impacts eventually affect consumers as regulators ban or companies abandon useful products, replacing them with second-best and often more expensive alternatives. Accordingly, it is critical that the NTP use the best available, peer reviewed science when making its decisions. Yet it clearly doesn’t do that.

First to testify today was NTP Director Dr. Linda S. Birnbaum, who defended the NTP process, but not very well if you read between the lines. When asked how the NTP comes to its conclusions, Birnbaum said NTP scientists review all the information on a chemical — both good and bad — and then they assemble the information indicating the chemical is a carcinogen when making the assessment. In essence, they review all the information, but then focus on the most damning information to make their decisions.

A scientific approach would instead focus on the best available, peer reviewed science and do a weight-of- evidence-test — placing greater emphasis on the best and strongest evidence. Based on Birnbaum’s comments, NTP does the opposite.

Dr. Richard Belzer, of Regulatory Checkbook, sheds even more light on the flimsy science at NTP. Belzer, who recently produced a paper for CEI on the topic, explained that the NTP relies on purely subjective terms — rather than terms with scientific meaning — which is a clear indicator that the agency’s decisions are largely subjective rather than scientific.

NTP’s direction in the law from Congress, he points out, is to list chemicals that are either “known to be carcinogens or may reasonably be anticipated to be carcinogens.” But Belzer explained: “Science does not ‘know’ or ‘reasonably anticipate’ things. Science cannot tell you whether a number is ‘significant.’ These are not scientific words. They are the words of lawyers.” He continues:

[T]the NTP has happily exchanged the starched white lab coat of science for the bureaucratic imperative of maximizing the number of substances listed. The NTP has achieved this by maximizing its flexibility to use (or reject) scientific information however it sees fit. Thus, while the NTP’s listing determinations have scientific content, they are not scientific determinations.”

NTP’s definitions of  “known,” “reasonably anticipated,” and “significant,” follow no known scientific standard.  For example, NTP’s definition of a known” carcinogen simply states: “There is sufficient evidence of carcinogenicity from studies in humans.”  Yet, this standard is “utterly opaque because no one outside the NTP knows what makes evidence ‘sufficient,'”  Belzer pointed out.

Belzer notes further that NTP basically ignores its direction from the law to consider exposure and risk levels — crucial elements in determining whether something truly represents a cancer risk. Instead, NTP prefers — as Birnbaum emphasized — to focus only on hazard. But hazard simply assesses whether something might pose a risk under some unspecified conditions or exposure. It does not determine if the product actually poses any risks at current exposure levels. For example, if we applied Birnbaum’s logic to  broccoli, NTP would have to list it as a carcinogen because chemicals found in broccoli give cancer to rats when dosed at very high levels. Ditto for water since drinking too much water at one time can kill you.

Several companies testified today on how NTP’s unwarranted demonization of styrene harms their enterprises. However, one business representative — Ally LaTourelle, Vice President of Government Affairs at BioAmber, Inc. — testified in favor of the NTP process and also said regulation promotes innovation. But this isn’t surprising since her company mission involves the development of “green” chemicals to replace the chemicals that become casualties of regulation, particularly petroleum based chemicals, which includes styrene. The company website explains: “BioAmber’s goal is to be the leading provider of renewable chemicals by replacing petroleum-based chemicals with its bio-based alternative.” In other words, when their competitors are demonized by government listings and regulation, BioAmber stands to benefit from increased market opportunities. And while Alley and her company probably have good intentions, there is no evidence that their products are safer or any better than the ones they hope to replace.

Clearly, Congress should take the lead in getting NTP on track or eliminate it altogether as its current approach is simply detrimental, as many of the businesses affected testified today. Belzer suggests reasonable reforms to the process. Check out his testimony and paper as well as his longer working paper on the topic for details on how to make NTP classifications more science based.  You can watch Belzer deliver his testimony on Youtube.