The Wyoming Attorney General petitioned the Environmental Protection Agency on Monday to stop implementing a ruling that gives the Eastern Shoshone and Northern Arapaho tribes new rights related to air quality on and near the Wind River Indian Reservation.

But the controversy between the state and the tribes is hardly about air. The core conflict grows out of a 108-year-old dispute about land and law.

The old dispute was given new life when the EPA ruled in favor of the tribes’ application to be treated as a state under the Clean Air Act. That ruling gives the tribe the right, among others, to receive automatic notification of any air quality permit applied for within 50 miles of reservation boundaries.

But in doing so, EPA also stated what it regards as the boundaries of the reservation. Relying on a 2011 finding by the Interior Department, the EPA ruled last month that the 1905 Act, which opened Riverton and as many as one million more acres to homesteading by non-Indians, did not diminish the reservation.

In other words, the ruling holds that land that the state, Fremont County and the city of Riverton consider to be under local jurisdiction is, in fact, Indian Country. And as part of the Wind River Indian Reservation, the city and surrounding area could be subject to federal policing, among other laws.

Attorney General Peter K. Michael believes the EPA ruling came to the wrong conclusion about the boundaries of the Wind River Indian Reservation.

The state announced that it was asking EPA for a stay of the ruling on Monday as Attorney General Peter K. Michael appeared at a hearing of the Select Committee on Tribal Relations in Fort Washakie.