On June 3, the U.S. Court of Appeals for the District of Columbia issued another major Resource Conservation and Recovery Act (RCRA) decision, albeit in an unpublished opinion. The case is Solvay USA v. EPA. In 2011, EPA issued rules to classify non-hazardous secondary materials under RCRA as “solid waste” for the purpose of Clean Air Act emission standards applicable to sludge incinerators and other combustion units. The rule is codified at 40 C.F.R. Part 241. As noted by the Court of Appeals , whether a facility is regulated by Clean Air Act (CAA) Section 7429 or 7412 has significant practical consequences for the regulated facilities. The Court of Appeals rejected the arguments of both the environmental and industry petitioners, holding that EPA’s interpretation of both RCRA and the CAA was entitled to considerable deference by the courts, and that the Administrative Procedure Act will only allow a court to set aside an action that arbitrary and capricious, and there is no evidence that it was. The Court of Appeals’ opinion is very brief (four pages) and will not be published. However, the Court of Appeals directed the clerk not to issue the mandate for seven days to give the parties time to seek rehearing or rehearing en banc.