Jump to Navigation
Jump to Content

National Ass'n of Clean Water Agencies v. Environmental Protection Agency

ELR Citation: 43 ELR 20191
Nos. 11-1311, (D.C. Cir., 08/20/2013)

The D.C. Circuit remanded EPA's "maximum achievable control technology" (MACT) standards for sewage sludge incinerators under CAA §129. The court upheld EPA's authority to regulate sewage sludge incinerators under §129, deferring to the Agency's interpretation of "solid waste incineration unit" as including sewage sludge incinerators. Nevertheless, the court remanded the rule for further clarification without vacating the MACT floor regulations. Specifically, EPA failed to demonstrate with substantial evidence that non-control technology factors apart from sewage sludge content, like variations in age, design, or operation of the incinerators themselves, would have a negligible effect on incinerator emissions. The court, therefore, remanded this portion of the rule. In addition, while EPA's use of the upper prediction limit may have been lawful, EPA must provide further explanation on the issues of how the upper prediction limit represents the "average emissions limitation achieved," how the upper prediction limit is a reasonable method of predicting the upper limit of the best performing incinerators, and how the upper prediction limit accounts for variability in incinerator performance when it is not based on a dataset representative of the best-performing incinerators under the worst-performing conditions. Finally, EPA must elaborate on how it can use a statistical method to determine whether a limited dataset is representative of incinerators for which it has no data, and it must explain why it chose the variables it did for that statistical analysis. The court upheld the rule against petitioners' challenges in all other respects.