The Southern District Court of Ohio has issued an opinion in Sierra Club, et al., v. Korleski that affects an exemption available under the Clean Air Act.

The case stems from the Ohio General Assembly's decision four years ago to amend the Ohio Revised Code provision that exempts new and modified under-10-ton sources of National Ambient Air Quality Standards (NAAQS) pollution from Best Available Technology (BAT) requirements. Four months later, the Ohio EPA revised Ohio Administrative Code, which exempted new or modified sources that have the potential to emit less than 10 tons per year of National Ambient Air Quality Standards pollution or precursors to NAAQS pollution, from employing Best Available Technology requirements. The BAT exemption took effect on Dec. 1, 2006. As a result, the director of the Ohio EPA ceased enforcing and implementing the BAT requirements against new or modified sources that emitted less than 10 tons per year.

In January 2008, the Ohio EPA submitted a State Implementation Plan (SIP) revision, containing the revised administrative code to the U.S. EPA for approval. In June 2008, the U.S. EPA concluded that it could not process the director's proposed state implementation plan because it was incomplete. However, the Ohio EPA continued to enforce the Best Available Technology exemption and the Sierra Club sued, alleging that Ohio EPA's adoption and enforcement of the revised Ohio Administrative Code violated federal law, primarily because it contained less stringent requirements than Ohio's current State Implementation Plan.

The Sierra Club argued that the Ohio EPA director had a duty not to enforce or adopt any emission standard or limitation less stringent than the emission standard or limitation in effect under an approved State Implementation Plan. In that regard, the Sierra Club alleged that the director of Ohio EPA breached his duty to enforce the Best Available Technology program and failed to follow the mandatory revision procedure required for State Implementation Plans. In response, the Ohio EPA maintained that the Clean Air Act and the corresponding federal regulations require states to adopt revised regulations as enforceable law before submitting them as SIP revisions for federal approval.

The U.S. District Court ultimately held that the director's failure to enforce and implement the Ohio SIP violated the Clean Air Act. Further, the Court held that the Best Available Technology exemption adopted and implemented in 2006 violated the Ohio SIP and the Clean Air Act. The Court further ordered the Ohio EPA director to implement and enforce the Ohio Administrative Code as set forth within the U.S. EPA-approved State Implementation Plan. The District Court ordered the Ohio EPA director to enforce Best Available Technology requirements against new and modified "under-10-ton-per-year sources" of NAAQS pollution.

The Ohio EPA director released a memo to Ohio's Division of Air Pollution Control permit writers and reviewers, stating that the BAT exemption cannot be used at this time. Instead, the director called for a case-by-case BAT determination for new or modified sources until such time as the BAT exemption becomes approved as part of the State Implementation Plan.