On Friday, January 4, 2013, the U.S. Court of Appeals for the District of Columbia Circuit ruled that the Environmental Protection Agency (“EPA”) must rework how it implements standards for fine particulates emitted by power plants, boilers and motor vehicles. In making its determination, the court rejected the EPA’s argument that it is required under the Clean Air Act to use a less stringent regime of implementation for standards related to fine particulates than it does for standards related to less dangerous, coarser particles. As a result, implementation of the two fine particulate matter regulations will likely become more rigorous, and more stringent controls will apply to power plants located in communities which are not achieving the relevant clean air standards.
In the case, the American Lung Association, the Natural Resources Defense Council, the Sierra Club, and the Medical Advocates for Healthy Air (“Petitioners”) challenged two final rules promulgated by the EPA under the Clean Air Act (“CAA”) during the George W. Bush administration. The rules governed the implementation of national ambient air quality standards for fine particulate matter. Fine particulate matter, commonly referred to as soot, is defined as having a diameter equal to or less than 2.5 micrometers (“PM 2.5”).
Petitioners claimed that the EPA ignored language in the Clean Air Act, as amended in 1990, which states that particulate matter implementation is addressed in a different section of the statute than implementation requirements for other types of pollution. Petitioners argued that the EPA had incorrectly formulated the PM 2.5 rules pursuant to Subpart 1 of the CAA, which contain general implementation provisions, rather than the provisions of Subpart 4, which are specific to particulate matter. The EPA disagreed with Petitioners’ reading of Subpart 4, responding that the CAA Subpart 4 language highlighted by Petitioners references only PM 10 (coarse particles have an indicator of “PM 10”), and as such applies only to the implementation of standards for coarse particles.
The court agreed with Petitioners’ interpretation that PM 2.5 is included in the statutory definition of PM 10, and ruled that references in the statute to PM 10 indicated that Congress was referring to particulate matter in general, and this general reference included PM 2.5. The court stated that Subpart 4’s language specifically dealing with particulate matter is far stricter than that of Subpart 1, and gives states less leeway with regard to mitigation techniques and timelines for addressing particulate matter clean air violations. Additionally, the court rejected the EPA’s contention that the Petitioners’ challenge was untimely for not having been filed when the 1997 standards were first finalized. The court found that the EPA’s PM 2.5 standards have been defined by EPA as interim since their inception, and concluded that Petitioners’ challenge was timely.