## Facts

- Summit Petroleum Corporation operated a natural gas sweetening plant in Rosebush, Michigan and roughly 100 sour-gas production wells with associated flares spread across about 43 square miles.
- The wells and plant were connected by pipelines; the wells were not physically connected to each other except by roads and utilities, and some wells were up to eight miles from the plant.
- Under the Clean Air Act Title V program, a “major source” may include “any group of stationary sources” that are “located on one or more contiguous or adjacent properties,” under common control, and within a single major industrial grouping.
- EPA Region 5 issued a single-source determination (2009, reaffirmed 2010) treating the plant, wells, and flares as one stationary source on the ground that the properties were “adjacent” because the facilities were functionally interrelated.
- Summit petitioned for review, arguing that “adjacent” requires geographic closeness and could not cover widely separated facilities based only on operational integration.

## Issues

1. Whether “adjacent” in the Title V “contiguous or adjacent properties” requirement permits EPA to aggregate physically separated facilities based on functional interrelatedness.
2. Whether deference is owed to EPA’s interpretation of “adjacent” when the regulatory text is asserted to be unambiguous.

## Decision

- The Sixth Circuit granted Summit’s petitions for review, vacated EPA’s single-source determination, and remanded.
- The court held that “adjacent,” in this regulatory context, is unambiguous and refers to physical and geographic proximity rather than functional relatedness.
- Because the regulation was unambiguous, the court declined to defer to EPA’s functional-relatedness approach.
- The court directed EPA on remand to determine whether the wells and plant are sufficiently physically proximate to be “adjacent” under the ordinary physical/geographic meaning of the term.
- Judge Moore dissented, concluding “adjacent” is ambiguous in this setting and would have deferred to EPA’s functional approach in light of the Clean Air Act’s regulatory purpose.

## Legal Principles

- A group of stationary sources may be aggregated as a single source under Title V only if the sources satisfy the “contiguous or adjacent properties” requirement, which focuses on physical location.
- Where a regulatory term is unambiguous in context, courts apply its ordinary meaning and do not defer to an agency interpretation that conflicts with that meaning.
- EPA may not replace a geographic adjacency requirement with a functional interdependence test when the text requires physical and geographic proximity.

## Conclusion

The Sixth Circuit invalidated EPA’s aggregation of Summit’s dispersed wells and sweetening plant as a single Title V “major source” because “adjacent” requires physical and geographic proximity, not mere functional interrelatedness, and remanded for EPA to apply that physical-proximity standard.


Summit Petroleum Corp. v. U.S. Env’t Prot. Agency, 690 F.3d 733 (6th Cir. 2012)