August 20, 2013 - The U.S. EPA was ordered today by federal judges to fully justify its methodology for how it set air standards for sewage sludge incinerators.
The U.S. Court of Appeals for the District of Columbia Circuit sent part of EPA’s 2011 maximum achievable control technology, or MACT, standards back to the agency for review.
In a complicated case, the rules were challenged from all sides. The Sierra Club contended that EPA’s methodology for baseline emissions limits, or the MACT floor, was flawed as under the Clean Air Act, EPA is required to set the floor based on the top 12 percent of performing facilities for all pollutants. A unanimous three-judge panel ruled that EPA had failed to justify its methodology, which only sampled incinerators in nine municipalities and then used statistical analysis based on state environmental agency data to set the floor.
“We agree that in some respects EPA has not adequately established that its estimations are reasonable,” Sentelle, a Republican appointee, wrote in an 88-page opinion.
Sentelle was joined on the panel by fellow Republican appointee Janice Rogers Brown and Chief Judge Merrick Garland, a Democratic appointee.
EPA had argued that the type of sludge being burned was fairly homogeneous across the country. Therefore, its statistical models could adequately estimate how well certain technologies cut back emissions uniformly, it said.
Senior Judge David Sentelle acknowledged that setting the MACT floor is “no simple task” and noted that courts have previously been willing to defer to EPA’s methodologies when it is unable to fully sample the top 12 percent of best-performing facilities. Furthermore, Judge Sentelle acknowledged that the EPA was rushed in setting the MACT floor by a court-ordered deadline. However, he argued that EPA’s methodology “involved several different estimations and assumptions,” and that most importantly, EPA appeared to disregard differences in the age of incinerators, how they are operated or variable designs in its calculations.
Industry also challenged the rule as incinerator owners, represented by the National Association of Clean Water Agencies, charged that EPA lacked the Clean Air Act authority to regulate incinerators because the sludge — which contains heavy metals like lead — doesn’t come from the public but, rather, from sewage treatment plants.
On this issue, the D.C. Circuit sided with EPA as during arguments in May, the judges focused on the word “from” in the Clean Air Act, arguing that it is ambiguous. Although the sludge comes to the incinerator from a treatment plant, sludge is still generated from the general public and is consequently, subject to EPA regulation.
Even though part of the rule was sent back to EPA, the court left the current MACT floor in place.