In December 2008, the Northern Arapahoe Tribe and the Eastern Shoshone Tribe—both of the Wind River Indian Reservation in Fremont and Hot Springs Counties in west central Wyoming—sought Tribe-as-State status under §301(d)(2) of the Clean Air Act, which provides an “express congressional delegation” to tribes of the EPA’s authority to regulate air quality on fee lands located within the exterior boundaries of a reservation. The tribes expended 82 of their 87-page application arguing that they possessed jurisdiction over Riverton. Because their application ignored a host of federal statutes and federal and state court rulings, in 2009, the State of Wyoming, the Wyoming Farm Bureau, and other entities filed comments opposing the application.
The Reservation, which is shared by the Tribes, was established in 1868. In 1904, the Tribes signed an agreement with the federal government ceding 1,480,000 acres of land, which were to be opened for sale under the homestead, townsite, coal, and mineral land laws, which was entered into with the United States Indian Inspector in exchange for per capita payments to tribal members and capital improvement projects inside “the diminished reserve” or Reservation. In 1905, Congress ratified the 1904 agreement.
In 1906, the ceded lands were opened for settlement by a Presidential Proclamation and allotments were sold to non-Indians in an area that today makes up Riverton. In 1939, some unsold ceded lands were restored to the Reservation, but a significant portion was not. Riverton is located wholly on lands ceded in the 1904 agreement and never restored to the Tribes.
On February 18, 2014, the Wyoming Farm Bureau Federation filed a petition challenging the EPA’s decision. On October 6, 2014, Wyoming filed its opening brief. On December 5, 2014, the Wyoming Farm Bureau Federation filed its opening brief. On January 5, 2015, Riverton and Fremont County filed their opening brief and Ten States filed a friend of the court brief arguing that the EPA should be granted no deference in deciding the lawsuit. On April 6, 2015, the EPA filed its opening brief. On April 23, 2015, the Eastern Shoshone Tribe filed its opening brief. On April 30, 2015, Indian Law Professors filed an amicus curiae brief in support of the EPA’s decision. On May 28, 2015, Riverton Memorial Hospital filed a friend of the court brief urging that the EPA’s decision be reversed. The EPA and Eastern Shoshone Tribe filed their response briefs on June 9, 2015, and June 10, 2015, respectively. On June 22, 2015, the Wyoming Farm Bureau Federation filed its reply brief.
On November 17, 2015, MSLF argued the merits before the Tenth Circuit. During oral argument, the Tenth Circuit requested additional briefing on the issue of whether the case was moot because the Tribes had dissolved their joint governing body. On December 1, 2015, the Wyoming Farm Bureau Federation filed its supplemental brief, arguing that the case is not moot because, pursuant to the EPA’s decision, its members will still be injured by the exercise of federal rather than state jurisdiction over their farming and ranching activities. On February 22, 2017, in a 2-1 ruling, the Tenth Circuit ruled in favor of Wyoming and the Wyoming Farm Bureau Federation after holding that MSLF’s client has standing to challenge the EPA’s decision. On July 10, 2017, the Northern Arapahoe Tribe and the Eastern Shoshone Tribe filed motions for rehearing en banc. The EPA did not file a motion for rehearing. On August 31, 2017, the Wyoming Farm Bureau Federation filed its opposition to the Tribes' petitions for rehearing.