On Friday, the Court of Appeals for the District of Columbia Circuit rejected EPA’s approach to implementation of the PM2.5 NAAQS. The fine particulate NAAQS was first published in 1997, and EPA issued implementation rules in 2007 and 2008. Those rules specified that EPA Subpart 1 of Part D of title I of the CAA – the general implementation provisions – rather than Subpart 4, which applies specifically to PM10. Because the Subpart 4 rules provide less flexibility and are more stringent, environmental groups sued, challenging EPA’s position.
In NRDC v. EPA 2013, the Court of Appeals never even got past Step 1 of the Chevron analysis, concluding instead that “the statute is plain on its face” in subjecting the fine PM standard to Subpart 4.
At a certain level, EPA’s argument was simple. The 1990 amendments applied Subpart 4 to PM10. EPA now regulates PM2.5 separately from the remainder of PM10. Thus, Subpart 4 should apply only to what is today regulated under the PM10 standard. Unfortunately, the Court found this argument too cute by half. PM10, as a formal matter, is any particulate matter less than 10 microns – which includes PM2.5. Moreover, in 1990, there was no concept of regulating the specific subset of PM now known as PM2.5. To the Court, it was obvious looking at the plain language of the CAA that Congress was using the identifying PM10 as the shorthand for all particulate matter regulated under Part D of the title I. Moreover, Congress found the PM problem to be sufficiently severe to create new – more stringent – implementation rules for PM than would apply under the general provisions of Subpart 1.
The irony that EPA established separate rules for PM2.5 because it concluded that PM2.5 was of even greater concern than the remainder of PM10, yet wanted to apply less stringent implementation rules on PM2.5 was not lost on the Court.
It makes no sense then that the Congress would have wanted EPA to relax Subpart 4’s more stringent, nondiscretionary requirements for implementing the PM2.5 standard at the same time EPA decided to strengthen the PM2.5 standard itself based on “evidence from numerous health studies demonstrating that serious health effects are associated with exposures to elevated levels of PM2.5.”
Out of office for almost four years, the Bush EPA is the gift that keeps on giving to environmental groups.