By R. Lee Vail

On January 26, 2011, the U.S. EPA denied petitioner’s request to reconsider the newly promulgated one-hour sulfur dioxide (SO2) national ambient air quality standard (NAAQS). See, 76 Fed. Reg. 4780. The EPA determined that the objections raised were not of “central relevance” purportedly because they failed to support an argument that the promulgated standards should be revised. The petitioners objected, in part, to non-binding preamble guidance concerning implementation issues that were separate and independent from revisions of the NAAQS. Since the EPA denied reconsideration, no need existed for a stay. 

Petitioner’s primary objection centered on perceived changes in EPA policy through utilization of modeling data to designate areas as non-compliant with the SO2 NAAQS. EPA countered that modeling had long been utilized “to determine whether areas have attained the NAAQS.” Petitioners also expressed concerns that modeling may over-predict violations. In its denial, the EPA countered that “modeling can very accurate identify areas of potential daily, maximum 1-hour concentrations above the NAQQS,” and if over-predictions exist, “interested parties would have a fair opportunity to show that using modeling in that case may not be appropriate.” See, 76 Fed. Reg. at 4782. Under this implementation process, the designation of non-attainment, based on modeling, will be the challengeable final decision.
 

“EPA explained that States may need to conduct other quantitative analysis, such as modeling, to identify where ground-level SO2 maximum concentrations may occur and where to site monitors.” See, 76 Fed. Reg. at 4784. Considering the EPA’s above strategy of “in non-attainment by modeling, out of non-attainment by showing the model is in error,” it will likely require that the interested party prove, through monitoring, that the model is inappropriate. Thus, the new approach may force “interested parties” to construct and operate monitoring stations to refute modeling results, resulting in a shift in the monitoring burden from the states to individuals. The rejection of modeling conclusions by the EPA would occur on a case-by-case basis. 

According to the EPA, “Nothing in the final promulgated rule prevents a state from basing its designation on monitoring data.” See, 76 Fed. Reg. at 4792. The EPA further stated that they have left open the possibility that they may accept such a designation, however, such is to be determined based on future guidance. Additionally, the EPA states that the guidance will be subjected to the notice-and-comment process. Consistent with the previous statements, the EPA concluded that neither the preamble nor the rule requires that the States perform modeling. Although the above statements support an EPA denial that an implementation strategy has been established, the non-binding guidance reflects the EPA’s current view of that which constitutes “the most accurate data to support” designations and SIP actions. In conclusion, the EPA flatly denied that it owes any substantive deference to State decision. See, 76 Fed. Reg. at 4797. 

The denial allows the litigation currently pending in the U.S. Court of Appeal for the DC Circuit, Montana Sulphur & Chemical Company v. EPA, to move forward.