The EPA's Risky Reasoning: Recent Revisions to the Air Quality Standards Show a Worrisome Misuse of Science

Coglianese, Cary, Marchant, Gary E., Regulation

FOR REGULATORY DECISIONMAKERS, science provides a systematic basis for understanding policy problems and the consequences of different policy options. Thus, scientific evidence needs to play a key role in agency decision-making. But even though science is valuable for what it can tell administrators about policy problems and their possible solutions, science does not by itself provide a complete reason for a policy decision because it does not address the normative aspects of administrative policymaking.

The Environmental Protection Agency's efforts to justify recent changes to its National Ambient Air Quality Standards (NAAQS) for ozone and particulate matter (PM) exemplify the use--and misuse--of science by government agencies. Given the way the EPA and the courts have interpreted the Clean Air Act, the agency has been able to cloak its policy judgments under the guise of scientific objectivity. By doing this, the EPA has evaded accountability for a shifting set of policy positions that have major implications for public health and the economy. The EPA'S incoherent approach to its NAAQS decisions ultimately fails to live up to the aspiration for reasoned decision-making that under-girds contemporary administrative law in the United States.

SCIENCE AND RISK STANDARDS

Throughout its recent ozone and PM rulemakings, which were finalized in July 1997, the EPA attempted to justify its selection of its air quality standards based solely on scientific evidence regarding the health effects of pollution. By purporting to rely on science to justify normative policy decisions, agencies like the EPA succumb to a category mistake because science speaks to what is rather than to what should be. Relying exclusively on science, as the EPA has done in its ozone and particulate rulemakings, is as misguided as it would be to disregard relevant scientific information altogether.

NON-THRESHOLD POLLUTANTS The Clean Air Act provides that in promulgating a new or revised NAAQS, the EPA must draw upon a "Criteria Document" that reflects "the latest scientific knowledge" of the health effects of the relevant pollutant. Then, under Section 109 of the act, the EPA is to set a standard that is "requisite to protect the public health" with "an adequate margin of safety."

The legislative history of the Clean Air Act provides some additional guidance for construing the brief statutory language. In 1970, when the current language of Section 109 was enacted, the Senate report on the legislation stated that the objective of air quality standards is to ensure "an absence of adverse effects on the health of a statistically related sample of persons in sensitive groups." NAAQS were intended to protect susceptible groups such as "bronchial asthmatics and emphysematics who in the normal course of daily activity are exposed to the ambient environment." Based on this language, the EPA and the courts have construed Section 109 to require air quality standards to "be set at a level at which there is 'an absence of adverse effect' on ... sensitive individuals."

Moreover, NAAQS must provide a "margin of safety" to ensure that "a reasonable degree of protection is to be provided against hazards which research has not yet identified." Thus, at least as reflected in the 1970 Senate report, the EPA is required to set NAAQS at a level that would ensure no detectable adverse health effects in even susceptible sub-groups of the population, and then to add an additional margin of safety to protect against unknown health risks that may be discovered in the future. In short, the NAAQS are apparently intended to provide near-absolute protection against adverse health effects.

The statutory provisions for adopting NA AQS, initially enacted in their present form in 1970, are based on the assumption that pollutants have thresholds for which it is possible to set a "safe" level. Such a "threshold pollutant" causes adverse effects only above a certain exposure level, which is designated as the threshold level. In contrast, a "non-threshold" pollutant is one that may cause adverse effects at any level above zero exposure.

For threshold pollutants, it would appear as if science alone might almost be sufficient to determine the level at which an air quality standard should be set. If a pollutant shows a clear threshold, then science would presumably provide the basis for using that threshold as a "safe" point below which the regulator could be assured the complete protection of public health.

But even with threshold pollutants, some judgments would still be required on the part of the EPA administrator. In particular, the administrator must make a clear policy judgment in selecting an "adequate margin of safety" to protect against uncertain or unknown health effects at lower exposure levels.

The need for making a policy judgment is even clearer for non-threshold pollutants. Unlike threshold pollutants, for which a standard can be set at a level below the threshold to provide complete health protection, the only way to protect against all adverse health effects from a non-threshold pollutant would be to set a standard at the level of zero. Given the continuum of health effects for the non-threshold air pollutants, no standard other than zero can provide complete and certain protection against all adverse health effects. As a result, when regulators set standards for non-threshold pollutants at levels other than zero, they must at least implicitly do so based on some criteria other than the science. That is because the …

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Publication information: Article title: The EPA's Risky Reasoning: Recent Revisions to the Air Quality Standards Show a Worrisome Misuse of Science. Contributors: Coglianese, Cary - Author, Marchant, Gary E. - Author. Magazine title: Regulation. Volume: 27. Issue: 2 Publication date: Summer 2004. Page number: 16+. © 2009 Cato Institute. COPYRIGHT 2004 Gale Group.

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