Yet another risk assessment finds BPA safe

While the media continues to report activist fears over chemicals in plastics, another risk assessment buttresses the overwhelming consensus in science that the chemical is safe.

“An expert panel led by scientists at Gradient Corporation in Cambridge, Massachusetts completed an extensive scientific review of the reproductive and developmental effects of bisphenol A. Based on its review of all the relevant scientific literature, the panel found no consistent evidence of reproductive or developmental effects of bisphenol A at typical human exposure levels. The review considered all studies published through July 2008 that examined reproductive and developmental toxicity in animals at low bisphenol A doses. No studies were excluded based on study design or source of funding.

According to Dr. Lorenz Rhomberg, the senior author of the review, “The hypothesis that the low levels of bisphenol A to which people are exposed could disrupt reproduction and development is not supported by coherent, consistent, or compelling evidence.”

This is the second review conducted by the Gradient corporation and the third major assessment funded by industry (the other was overseen by Harvard’s Center for Risk Analysis).

Some scientists, notably the George Washington university epidemiologist David Michaels have expressed doubt about industry-sponsored studies of BPA, noting that independently funded studies have found a risk where industry funded studies haven’t.

But the findings of these three industry-sponsored reviews all concur with the findings of independent risk assessments conducted by the European Union’s Food Safety Authority, the Japanese government, NSF International, and the Center for the Evaluation for Risks to Human Reproduction in the U.S. (Moreover, in his article for the Washington Post, Michaels radically undercounted the number of studies on BPA and ignored the problem of whether good laboratory practices were followed in the independent ones; an independent study with a sample size of six rodents is not going to have the statistical reliability of an industry-funded study containing hundreds of rodents).

Given that so many scientists have concluded that there are no reproductive or endocrine risks from BPA, the media need to start questioning whether the risks claimed for BPA by a handful of scientists and a heaped serving of environmental activists are actually based on firm science.

7 Responses to Yet another risk assessment finds BPA safe

  1. The Harvard Center for Risk Analysis and Gradient Corporation have some credibility issues. In a 2007 paper in PLoS Biology, Liza Gross wrote:

    Founded in 1989, the Harvard Center for Risk Analysis (HCRA) long specialized in minimizing human health risks from its benefactors’ products, starting with the tobacco industry. Internal documents released through the 1998 Tobacco Master Settlement Agreement reveal how HCRA founder John Graham signaled industry that its business was his business. In a 1991 fund-raising letter seeking US$25,000, Graham told Philip Morris’s vice president of government affairs of his need “to learn more about the risk-related challenges that you face.”


    Gradient Corporation, the environmental consulting firm that wrote the HCRA follow-up review on bisphenol A, also cut its teeth on the tobacco industry. In the early 1990s, Gradient received nearly US$700,000 from RJ Reynolds, according to internal documents released through the tobacco settlement, to estimate dose-response relationships “for the purpose of comparing the biological activity of the New Cigarette with the standard cigarette.” The two Gradient principals working on the project offered RJ Reynolds expertise in cigarette toxicology and inhalation toxicology.

    Gradient’s game, says Richard Clapp, professor of environmental health at Boston University’s School of Public Health, is product defense. Its services include promoting industry positions in op-eds, providing expert testimony in court, legislative, and regulatory proceedings, and issuing scientific reports. “They wind up defending people who are worried about liability,” Clapp says, “though they would say they’re there to make sure that there’s sound science behind whatever regulatory steps or litigation happens in this country.”

  2. Thanks for the info.
    Are they concluding it is safe for infants?

  3. The European Union has concluded it is safe for infants in a 2006 risk assessment conducted by the EU’s Food Safety Authority, and in a follow up study evaluating new research in July 2008. The risk assessments, conducted by independent scientists within the EU specifically looked at maternal/fetal risk and found no cause for concern. In fact, the EU raised the Tolerable Daily Intake by a factor of five. The EU has also criticized recent concerns in the U.S. over the safety of BPA as drawing on methodologically flawed science.

  4. Bob Herrick says:


    What would be persuasive would be a deconstruction of the lab techniques used or of the experimental design, or an alternative analysis of their data. Ad hominem, particularly after the elections, has the opposite effect on me than that which you intend.

  5. Bob, I see your point. Indeed, the Wikipedia page on Ad Hominem says:

    Ad hominem arguments are always invalid in syllogistic logic, since the truth value of premises is taken as given, and the validity of a logical inference is independent of the person making the inference.

    But it goes on to say:

    However, ad hominem arguments are rarely presented as formal syllogisms, and their assessment lies in the domain of informal logic and the theory of evidence. The theory of evidence depends to a large degree on assessments of the credibility of witnesses, including eyewitness evidence and expert witness evidence. Evidence that a purported eyewitness is unreliable, or has a motive for lying, or that a purported expert witness lacks the claimed expertise can play a major role in making judgements from evidence.

    Credibility matters, which is why, for example, medical journals require that authors are up front about possible conflicts of interest.

  6. Yes. But what about the credibility of someone who argues that credibility is at stake but fails to indicate why the Gradient study is flawed as science?

    For example, the industry-sponsored risk assessment conducted by Harvard noted that the Vom Saal anti BPA camp based their arguments on risk on finding any endpoint that suggested a risk but ignoring all endpoints that showed no risk.

    In other words, any endpoint could count as an indication of BPA’s risk, irrespective of the manner or method of its determination, but nothing counted as proof that it wasn’t a risk. The Harvard risk assessment offers a complex argument as to why the data points positing risk are not relevant or flawed; the anti-BPA response has been to ignore the weaknesses in their own argument and simply assert, in the face of objective, which is to say, testable, scientific objections, that the other side are corrupted by industry.

    What this suggests, perhaps, is that one should both apply issues of conflict of intereste equally (the anti-BPA research are, after all, reaping fat research grants given the level of public controversy), and then see whether each side has succeeded or failed in accounting for the other’s evidence. In other words, determine whether each player is being scientific. The crucial, salient aspect, missing in the media coverage, is that an overwhelming majority of risk assessments, both independent and industry sponsored have concurred on both the safety of BPA, and the fragility of the evidence against the chemical.

    The anti-BPA movement has too often relied on mendacity rather than statistical or methodological rigor to advance its message, notably by claiming that the body of evidence that BPA is safe is all industry-funded and therefore impeachable.

    I find that appalling; but my colleagues in the media seem okay with this profoundly unfair – and I would argue, unethical – state of affairs.

  7. Research grants (“fat” or otherwise) exist to support scientific research. The multi-billion dollar BPA industry exists to make a profit. Trying to expand the notion of conflict of interest to include research grants is, to borrow your words, appalling and unfair.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


Get every new post delivered to your Inbox.

Join 38 other followers