Like many other federal environmental protection laws, the Clean Air Act contains a provision (42 U.S.C. § 7604), which allows a private citizen to sue to enforce the statute, but (a) conditions that right on the citizen’s giving 60 days pre-suit notice to the federal agency enforcing the law, and (b) bars private actions when the federal agency or a state “has commenced and is diligently prosecuting” a civil action “to require compliance with the standard, limitation, or order” that the citizen is also seeking to enforce.  If an agency or state action bars the private citizen’s suit, the section grants the citizen a right to intervene in the government’s suit.  Here, a citizen tried to intervene in the government’s suit against VW for its fraud in installing mechanisms that defeated pollution tests on its diesel motored vehicles. However, the Ninth Circuit held that the district court correctly denied the intervention motion because neither the government nor the intervenor sought to enforce a “standard, limitation, or order.”  So the government suit didn’t bar the would-be intervenor from filing his own suit, and thus also did not grant him the right to intervene in the government’s action.

Ninth Circuit Court of Appeals (Berzon, J.); July 3, 2018; 2018 U.S. App. LEXIS 18135