A federal appeals court today threw out U.S. EPA's decision to extend a compliance deadline for its ozone air standard, as well as the agency's revoking a stringency requirement for transportation projects.

In both instances, the U.S. Court of Appeals for the District of Columbia Circuit ruled that EPA's actions exceeded its authority under the Clean Air Act.

The case brought by the Natural Resources Defense Council concerned what amounted to a compliance extension built into EPA's 2008 National Ambient Air Quality Standard for smog-causing ozone.

EPA finalized implementation regulations for the 75-parts-per-billion standard May 21, 2012. In doing so, the agency started the clock for compliance for some areas at the end of that year. So an area deemed to be in "marginal" nonattainment -- which is granted three years for compliance -- would have until Dec. 31, 2015, rather than May 21, 2015, to meet the standard.

Judge Srikanth Srinivasan, writing for the majority of the three-judge panel, said the law doesn't allow such an extension.


"We conclude that both challenged aspects of EPA's regulations implementing the 2008 ozone standards exceed the agency's authority under the Clean Air Act," Srinivasan wrote.

The law explicitly prescribes "against allowing the agency's lengthening of the periods for achieving compliance with revised air quality standards. ... [W]e conclude that the rule's deadlines cannot be squared with the statute."

Srinivasan also sided with the environmental group's argument that the plain text of the Clean Air Act prohibits EPA from revoking a requirement that transportation projects comply with regional implementation plans for areas failing to meet attainment for the 1997 ozone NAAQS. NRDC had argued that such a move would allow unlimited ozone emissions for new transportation projects in those areas.

"[W]ith regard to the revocation of transportation conformity requirements, the terms of the statute straightforwardly require maintaining those requirements for affected areas," Srinivasan wrote.

The impact of the ruling will likely be limited because EPA is currently revising its ozone standard and has proposed lowering it to between 65 ppb and 70 ppb.

Srinivasan was joined in the majority by Judge David Tatel. They are both Democratic appointees. Senior Judge A. Raymond Randolph, a Republican appointee, dissented and said he would have deferred to EPA's reasoning. The court held arguments in the case more than a year ago, suggesting some difficulty in coming to a conclusion in the case (E&ENews PM, Nov. 22, 2013).

Click here for the opinion.