Are Chemicals Killing Us?


That was the teaser question for a press conference this morning organized by the Society of Toxicology (SOT), the Center for Health and Risk Communication at George Mason University, and the Statistical Assessment Service (STATS) think tank.  The groups were reporting the results of a recent Harris poll of full members of the Society of Toxicology that aimed to determine the collective judgments of toxicologists on chemical health risks. In addition, the survey asked toxicologists how well they thought environmental advocacy groups, industry, government and media do in explaining chemical risks to the public.

The online survey, done in conjunction with the leadership of the Society of Toxicology, was sent to all of its 3600 full members and got a 30 percent (937 members) response rate.  Of the respondents, 37 percent worked in industry, 25 percent in academia, 15 percent were associated with government, and the remaining members were spread among non-profit organizations, consultants, and contractors.  Apparently, as a proportion of the SOT's membership, academicians were over-represented and industry toxicologists were under-represented.

With regard to chemical health risks, only one of out of three toxicologists surveyed thinks that food additives post significant health risks, and one out of four think that cosmetics are risky. On the other hand, more than half think that pesticides and endocrine disruptors (substances that mimic hormones) are significant sources of chemical health risk.

Ninety-two percent of toxicologists disagreed with the assertion that "any level of exposure is unacceptable for chemicals that have been identified as carcinogens, mutagens, or reproductive toxicants."  In addition, 81 percent rejected the notion that the detection of any level of a chemical in your body indicates a significant health risk. And, 87 percent disagreed with the claim that organic or "natural" products are safer than other products.  Seventy percent were against using the precautionary principle as a guide to risk regulation.  The precautionary principle mandates that a substance suspected to cause harm should be banned even in the absence of scientific consensus.

So whom should the public trust when it comes to information about possible health risks from exposures to chemicals? Certainly not environmental advocacy groups:  96 percent of toxicologists believe that Greenpeace overstates chemical health risks; 85 percent says the Environmental Defense Fund does too; and 79 percent believe that the Environmental Working Group, the Natural Resources Defense Council (NRDC), and the Center for Science in the Public Interest overstate risks.  On the other hand, about 60 percent believe that industry lobbyists such as the American Chemistry Council and the Pharmaceutical Researchers and Manufacturers of America understate chemical exposure risks.

In general, the majority of toxicologists think that government agencies are fairly accurate in portraying chemical health risks, although 41 percent thought the Environmental Protection Agency overstated risks and 40 percent thought the agency was accurate in its risk portrayals.

During the question and answer session, a representative from the NRDC complained that the survey results were being released before peer review during the press conference.  STATS president Robert Lichter pointed out that survey results are generally released without peer review, although the SOT and STATS plan to publish their results in a peer reviewed journal in the future.  Lichter then archly asked if the NRDC ever released data without peer review. The NRDC representative replied, "We're an advocacy group and we don't hold ourselves out as scientific researchers. We don't do peer reviewed science. Everybody knows that."

The media reporting on chemical heath risks came in for a huge drubbing in the survey. Over 80 percent of toxicologists believe that national newspapers, magazines, local newspapers, cable news, broadcast and local TV news overstate the risks of chemicals. Two-thirds thought that public broadcasting reports were overstated.  The best media sources for risk information? Wikipedia and WebMD, clocking in 45 and 56 percent accuracy respectively in the survey. "Apparently, the members of the Society of Toxicology believe that any guy off the street can do a better job reporting on chemical risks than major national media outlets," said STATS president Robert Lichter. While toxicologists don't like media reporting, two-thirds also believe that the peer review system is becoming overly politicized.

The survey also asked toxicologists to rate the riskiness of various chemicals that have been in the news lately. I found the results of this part of the survey a bit odd. The default setting for toxicologists seems to be that any given chemical substance poses a medium risk. Risk must be distinguished from hazard.  A hazard is something that can cause harm (lightning, bears, knives) and risk is the chance that a hazard will actually cause harm.

Now for the oddness.  Apparently, 48 percent of toxicologists believe that current exposures to bisphenol A, which is used to make polycarbonate plastics like those in baby bottles, represent medium to high risk. This is still quite scientifically controversial, but let that go. But the STATS evaluation of risk by experts turns strange (at least to me) when the SOT survey also finds that 47 percent of toxicologists believe that current exposures to high fructose corn syrup, used in a huge variety of foods, pose high to medium risks. What I fear is happening is that toxicologists are getting their information about the risks posed by chemicals that they do not themselves study from the same sources that most Americans do—newspapers, magazines, TV.  You know, the same media that SOT members think are doing a terrible job reporting toxicological risks. On the other hand, maybe high fructose corn syrup is dangerous. Oh well, at least consumers and farmers can take heart when two-thirds of toxicologists think that genetically modified organisms are low risk.

For more information about the SOT chemical risk survey go to here.