A ruling by the U.S. Court of Appeals for the D.C. Circuit reframes EPA’s authority to issue Clean Air Act (CAA) rules in Indian country (Oklahoma DEQ v. EPA). 

Regarding EPA’s imposition of a federal implementation plan (FIP) for New Source Review (NSR) on nonreservation Indian lands in Oklahoma, the court decided that the Agency asserted authority that rightfully belongs to the state because the EPA did not demonstrate that a tribe has jurisdiction over those lands.  Since the EPA did not make such a demonstration, the court vacated the NSR portion of the Indian country FIP with respect to nonreservation Indian lands.

State authority

The case highlights the different jurisdictional issues affecting reservation and nonreservation lands in Indian country.  The CAA provides that each state must be responsible for ensuring air quality within its borders.  The Act also treats Indian tribes as states.  When a tribe does not develop a tribal implementation plan (TIB) to carry out the functions of the CAA, the EPA must issue an FIP to fill the gap.  A tribe (and, in its stead, the EPA) may develop implementation plans for both for reservation lands and nonreservation lands in Indian country.  However, in its 1998 tribal authority rule, the EPA specified that a tribe need not demonstrate its jurisdiction for implementing CAA plans only for reservation lands.  In a 2000 rule, the D.C. Circuit upheld this rule. 

Indian country NSR rule

However, in 2011, the EPA issued its Indian country NSR rule, in which the Agency attempted to extend its authority over Indian lands by establishing an FIP process, including an NSR program, covering all Indian country nationwide except where the EPA had already either approved a tribal NSR program or expressly authorized a SIP to be enforced.  In the rule, the Agency stated that “states generally lack authority to regulate air quality in Indian country.”  The Oklahoma petition challenged the 2011 rule by asserting its SIP authority over nonreservation lands.

Specifically, Oklahoma argued that its SIP applies to nonreservation Indian country within the state because:

1. Regulatory jurisdiction under the CAA must lie initially with either a tribe or a state;
2. A tribe may exercise jurisdiction over nonreservation Indian country only if it demonstrates its authority to so do;
3. The EPA, when instituting an FIP for want of a TIP, may exercise no more jurisdiction than the tribe in whose stead it acts; and
4. (4) Neither a tribe nor the EPA has made a demonstration of tribal jurisdiction over any, much less all, nonreservation lands in Indian country.

According to the D.C. Circuit, at the core of the conflict is the CAA provision that either a state or a tribe has authority to implement air quality plans under the CAA.  If a tribe does not issue an implementation plan in an area over which it has clear jurisdiction (i.e., reservation lands), the EPA may fill the shoes of the tribe without the need to establish jurisdiction.  In other words, in this role, the EPA possesses no more authority than the tribe it is standing in for. 

Furthermore, the court states, it is the state, not the tribe or the EPA, that has regulatory jurisdiction over all territory outside the borders of an Indian reservation except insofar as an Indian tribe or the EPA has demonstrated that a tribe has jurisdiction over those areas.
“Until such a demonstration has been made, neither a tribe nor the EPA standing in the shoes of a tribe may displace a state’s implementation plan with respect to a non-reservation area of the state,” concludes the D.C. Circuit. 

Accordingly, the court vacated the Indian country NSR rule with respect to nonreservation Indian country.  

Oklahoma DEQ v. EPA