D.C. Circuit Renders a Welcome Decision on Ozone NAAQS

In 1977 amendments to the Clean Air Act, the Congress created the Clean Air Scientific Advisory Committee (CASAC), a body of scientists whose job is to advise EPA on the setting of National Ambient Air Quality Standards (NAAQS).

NAAQS is the primary regulatory regime established by the Clean Air Act. The regulation does exactly what its name suggests–it establishes numerical nation-wide ambient air standards for “criteria” pollutants (sulfur dioxide, lead, particulate matter, ozone, nitrogen oxides, and carbon monoxide). There are two types of NAAQS: primary and secondary. Primary NAAQS are set at levels requisite to protect public health, with an adequate margin of safety, while secondary NAAQS are set at levels necessary to protect public welfare.

EPA is required to take CASAC’s advice into account, and, when it publishes any NAAQS, the agency must explain any differences it had with CASAC’s advice. In 2006 and 2008, George W. Bush’s EPA promulgated revised primary NAAQS for particulate matter and ozone, respectively. Both of the regulations were set at levels that were less stringent than the range recommended by CASAC.

In a 2009 ruling, American Farm Bureau Federation v. EPA, the D.C. Circuit Court rejected Bush’s 2006 primary NAAQS for particulate matter. The court reasoned that the agency had inadequately explained its differences with CASAC’s advice.

In a ruling announced last Monday, Mississippi et al. v. EPA, this same court upheld Bush’s 2008 ozone primary NAAQS, despite the fact that it was less stringent than what CASAC had recommended. This time, the court found that EPA had adequately explained the difference.

By the Court’s own admission in the Mississippi et al. v. EPA opinion, there are no clear cut criteria by which EPA’s reasoning is judged. The primary standard seems to be derivative of whether CASAC’s advice is rooted in science versus policy considerations. The former (science considerations) is construed as pertaining to the component of the primary NAAQS that is requisite to protect public health. The latter (policy considerations) is the component of the primary NAAQS that represents an adequate margin of safety. The Court reasoned that EPA’s discretion rises along a decision-making continuum, from “science” to “policy” differences with CASAC. CASAC’s judgment matters more for science–in practice, determining a NAAQS level requisite to protect public health. EPA’s judgement matters more for policy–in practice determining the NAAQS level necessary to achieve an adequate margin of public safety. In this instance, the judges found that CASAC hadn’t explicitly stated which parts of its recommended ozone NAAQS were science-based reasoning, and which parts were policy-based reasoning. In the face of this uncertainty, EPA’s explanation met the low bar by which an agency’s decision is deemed reasonable.

Having read both opinions, I couldn’t discern any standard other than a judgment call. There are fourteen judges on the D.C. Circuit, which hears the preponderance of challenges to EPA rules, and they adjudicate cases in panels of three. As a result, it is entirely possible for the court to be of different minds on the same issue, which seems to be the case here. Only one judge served on both panels. I get the sense that the 2009 panel wanted to defer to CASAC, the 2013 panel wanted to defer to EPA, and each one found a reasoning to do so.

Whatever the case, it’s a welcome development. The 2009 American Farm Bureau Federation decision had suggested that EPA, in practice, did not have the discretion to disagree with CASAC on where to set primary NAAQS. This was scary, because CASAC members are taken from a talent pool of epidemiologists and practitioners of other dubious disciplines that always produce “scientific” results indicating the public health importance of their own work. As a result, it’s pretty much impossible to nominate a reasonable CASAC. If its power was unchecked, CASAC would not have limited itself. This is the rare case whereby affording EPA administrator relatively more authority is a good thing, because the alternative is worse.