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Sierra Club v. Environmental Protection Agency

ELR Citation: 48 ELR 20045
Nos. 16-1021, (D.C. Cir., 03/16/2018)

The D.C. Circuit granted in part and denied in part petitions concerning EPA's NESHAPs for industrial boilers. The first challenge raised by environmental groups concerned regulations that indirectly control a group of organic pollutants by limiting carbon monoxide emissions as a proxy for the targeted pollutants. After calculating emissions limits for the organic pollutants by reference to the amount of carbon monoxide emitted by the best performing boilers in each subcategory, EPA concluded that the lowest of the carbon monoxide limits were too low, so it substituted a single, higher limit that it deemed sufficient to control the pollutants. The court agreed with the groups that EPA's "about-face" was unjustified because it failed to explain how the revised limits would minimize the targeted pollutants to the extent the CAA requires. This portion of the rule was therefore remanded to EPA. The second challenge concerned rules governing how boilers operate while starting up and shutting down. Because conditions inside a boiler are in flux during this period, EPA found it infeasible to set numeric limits on pollutants during startup and shutdown. Instead, the Agency set qualitative “work practice” standards. The groups argued that those work practice standards give boiler operators unlawful leeway to pollute. But the court disagreed. The standards are permissible because, consistent with the CAA, they reasonably approximate what the best-performing boilers can achieve.