Ohio Court of Appeals Clarifies “Potential to Emit” and the Meaning of Stack Test Violations

In State of Ohio v. The Shelly Holding Company, the State of Ohio filed an action seeking injunctive relief and civil penalties against the defendants for violations of the Ohio Clean Air Act law and regulations. Two issues addressed by the Court of Appeals are worth mentioning. First, the Court addressed what types of emission limitations should be included in calculating a source’s potential to emit. Second, the Court addressed how to properly determine the duration of an emission limitation violation based on a stack test result for purposes of calculating the appropriate civil penalty.

With respect to potential to emit, the Court of Appeals rejected the State’s argument that only “federally enforceable” emission limitations can be relied upon in determining a source’s potential to emit, and concluded that in addition to “federally enforceable” limits, limits that are “legally and practically enforceable by the state” also can be relied upon to determine a source’s potential to emit. The Court then held that a source-owner’s self imposed limits contained in a source’s permit application are not limits that are “legally and practically enforceable” by the state, and that the trial court erred by allowing the defendant to rely on limits placed by the owner on the hours of operation in the source’s permit application.

With respect to the stack tests, the trial court rejected the State’s argument that a stack test violation continued until the next test established that the source was in compliance with its emission limitation, and concluded that a stack test violation constituted only a single violation. The Court of Appeals reversed, holding that the trial court should have concluded that the violation continued until the next stack test established that the source was in compliance.

On the stack test violation, the opinion is not clear whether the defendant could have used evidence other than a stack test to establish subsequent compliance of the source or to cut off the continuing violation; however, it did cite a Federal District Court case from Ohio that would support a defendant’s ability to cut off the continuing violation by presenting evidence establishing a basis to do so. Thus, depending on the nature of the stack test and the emissions limitation that is at issue, one could make arguments relying upon how often a source was operated that a mass-based limit over time was not violated. For example, if there is a daily mass-based emission limit of 1 ton, a stack emissions test showing emissions of 0.1 ton per hour would only establish violations of that daily limit on days when the unit operated for more than 10 hours.

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