Shackling EPA Risk Assessment

EPA pollution regulations are based on an assessment of the risks posed by pollutants. This can be a complex scientific judgment. CASAC, the agency’s scientific advisory board, is pushing for major changes in the way that EPA approaches this analysis. The effect would be to make it much harder for EPA to prove that a risk exists.

Currently, risk assessment is based on a “weight of the evidence” approach that considers all of the peer-reviewed literature , rather than limiting itself to studies using specific methodologies. Tony Cox, the industry consultant who now heads CASAC after Scott Pruitt purged most academic scientists, has been pushing for a radical change. He wants to limit risk assessment to studies that use a specific set of methods to establish that a substance actually causes harm. In particular, he rejects studies that show a correlation between exposure to the substance and adverse health effects after controlling for other factors. Instead, he wants studies that use certain statistical tests for causality. He drafted a caustic report on EPA’s current scientific appraisal of particulate air pollution on behalf of CASAC.

The argument for relying only on the most rigorous evidence and ignoring everything else seems plausible, but it’s wrongheaded. It would be like saying that, regardless of the other evidence, no criminal defendant could be convicted without video of the crime, fingerprints, and DNA evidence.

Epidemiologists, the scientists who study health risks, were aghast at the draft CASAC report. (Notably, there aren’t any epidemiologists on the committee these days.) Yesterday, the journal Science published a piece sharply criticizing this effort to overturn the weight of the evidence approach. There was also strong pushback from the scientific unit at EPA which does risk assessment. Perhaps in response to these criticisms, Cox seems to be softening the language in the final version of the report to EPA, though it’s not clear if there’s any real change in substance. E&E News also notes that CASAC is asking for more help. There used to be a separate expert committee on particulate pollution formed to advise CASAC on particulates. Wheeler disbanded that panel in October, apparently preferring to do without that kind of expert input. CASAC wants the panel reinstated.

CASAC’s credibility as a source of disinterested expertise took a hit when the academics were purged. The pretext for getting rid of them was that receiving EPA grants biased them in favor of EPA’s work, Since EPA is one of the major funders of this kind of research, a lot of serious scientists were eliminated. On the other hand, being funded by industry was considered perfectly ok.

The effort to handicap risk assessment isn’t doing much to restore CASAC’s credibility. But it is part of a larger pattern of trying to shape the outcomes of regulatory proceeding by systematically cutting back on consideration of regulatory benefits. It will be interesting to see how courts respond.

air pollution, PM2.5, risk assessment