The U.S. Court of Appeals for the Sixth Circuit overruled the Environmental Protection Agency's (EPA) decision that Summit Petroleum Corp's natural gas sweetening plant and its related sour gas production wells in Rosebush, Michigan, constituted a single source under Title V of the Clean Air Act.

As a single source site, Summit Petroleum would be required to apply for a permit from the EPA to operate the plant as all of the wells and the plant generate 100 tons of sulfur dioxides and nitrous oxides combined per year. However, if the wells are not included in the site then the plant is not required to file a permit with the EPA.

Although the plant and the wells are functionally interrelated, the court stated that the EPA had not followed the common meaning of "adjacent" as the facility and the wells are located throughout a 43-square-mile area. The company does not own the land between the wells and the plant, which vary between 500 feet and eight miles apart.

"Summit … argues that the EPA's determination that the physical requirement of adjacency can be established through mere functional relatedness is unreasonable and contrary to the plain meaning of the term 'adjacent.' We agree. For these and other reasons fully set forth herein, we vacate the EPA's final determination and remand this case to the EPA to determine whether Summit's sweetening plant and sour gas wells are sufficiently physically proximate to be considered 'adjacent' within the ordinary, i.e., physical and geographical, meaning of that requirement," the court said in its final decision.

This ruling could have a large effect on the EPA's permitting program. Should this decision hold it is likely that other facilities that have been required to file permits with the EPA under its looser definition of adjacency will seek to have such decisions overturned.