Two Wins in a Week for EPA on NAAQS: The DC Circuit Upholds EPA’s New SO2 Standard

On Wednesday, I discussed the DC Circuit’s decision affirming EPA’s revised NAAQS for NOx. Today, the DC Circuit upheld EPA’s revised SO2 standard. The tenor of today’s decision, written by David Sentelle, another Reagan appointee (the NOx decision was written by Douglas Ginsburg), is fairly similar to that in the NOx decision. Here’s the short version of the opinion:

EPA must establish NAAQS that protect public health with “an adequate margin of safety.” For that reason, it is appropriate for EPA to establish standards below levels at which studies have shown harm to occur. EPA may not cherry-pick data, but as long as it provides a reasoned explanation for why it has relied on some studies and not others, the courts will not consider EPA to be cherry-picking and will defer to EPA’s expertise. Consultation with the Clean Air Scientific Advisory Committee is important and promulgation of a standard consistent with CASAC recommendations is probably necessary and sufficient to insulate the rule from adverse judicial review.

I think I could write this opinion in my sleep at this point and I’m not sure much more than the paragraph above is necessary. I suspect that Judges Sentelle and Ginsburg feel the same way.

At a practical level, the most important part of the opinion did not relate to the standard; it was the court’s decision to dismiss as premature challenges to EPA’s stated intention to measure compliance with the standard through a “hybrid analytic approach” that includes modeling as well as air monitoring. I know that the Sierra Club and other environmental groups are already asserting to state agencies that, based on modeling, coal-fired power plants are causing exceedances of the new NAAQS, so this is an important issue.

The Court found that, because EPA’s statement was only in the preamble to the rule and did not impose “definite requirements upon states or regulated industries”, it was not final action subject to review. Stay tuned on this issue. Once EPA finalizes a rule – or guidance functioning as a rule – there will be renewed judicial challenges.

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