In GreenLatinos v. Suncor Energy (U.S.A.), Inc., the U.S. Court of Appeals for the Tenth Circuit revived a citizen suit brought by GreenLatinos, Sierra Club, and 350 Colorado alleging that Suncor’s Commerce City refinery had repeatedly violated the Clean Air Act despite decades of federal and state enforcement efforts. The district court dismissed the case, concluding that earlier EPA consent decrees and subsequent enforcement actions by federal and state regulators barred the lawsuit under the Clean Air Act’s “diligent prosecution” provision, which prevents private enforcement actions when the government is already pursuing the same violations.
The Tenth Circuit reversed, holding that the district court applied the wrong legal standard. The court ruled that the diligent-prosecution bar applies only when the government is currently prosecuting the same emission standards or limitations in an ongoing judicial action, not merely related or substantially similar violations. While long-standing consent decrees can qualify as ongoing judicial actions if they continue to be actively enforced, the court emphasized that administrative enforcement actions alone are insufficient to trigger the statutory bar. The court further held that the district court erred by treating “substantially similar” claims as equivalent to the “same” standards or limitations required by the statute.
The court remanded the case to determine whether Suncor’s alleged violations involved the same standards covered by the existing consent decrees and, if so, whether the government’s enforcement had been sufficiently diligent. Read the opinion.