Reno-Sparks Indian Colony v. United States Environmental Protection Agency

This appeal presents the question whether the Clean Air Act program to prevent deterioration of air quality is administered in Nevada: (1) in large air quality planning units encompassing all or nearly all of the state, or (2) in more than 250 smaller units designated by the State. The importance of the issue arises from the fact that certain pollution controls go into effect for a unit when a major pollution source applies for a permit within that unit. If the unit is very large, then a major source almost certainly has already applied, and new minor sources are subject to the controls in issue. If the unit is but one of hundreds in the State, then many units are not subject to the controls because no major pollution source is located within the unit. Minor sources are then *902 free to begin operating there without the special pollution controls.

Petitioners Reno-Sparks Indian Colony and Great Basin Mine Watch (collectively “Reno-Sparks”) contend that a mine that proposes to operate near the Colony is subject to the controls in issue because the relevant unit is the entire State or nearly so. The EPA issued a rule, however, stating that Nevada is divided into more than 250…