UPDATED to include comment from Gov. Matt Mead.

(Riverton, Wyo.) – In a letter dated this morning from Environmental Protection Agency’s Regional Administrator Shaun L. McGrath, the agency put a stay on its December ruling regarding the Wind River Indian Reservation’s treatment as state, pending future court rulings or other action.

“The U.S. Environmental Protection Agency (EPA) today sent a letter to the State of Wyoming, the Eastern Shoshone Tribe, and the Northern Arapaho Tribe communicating the Agency’s decision to stay the effect of its Wind River Reservation boundary determination for purposes of the Tribes’ implementation of certain non-regulatory provisions of the Clean Air Act,” the agency said in a news release. “The stay will apply to the City of Riverton, among other areas. EPA will continue to work with the Tribes to move forward on Clean Air Act activities in those areas that are not disputed by the State of Wyoming.”

The agency is holding implementation of its ruling due to requests from the state and the tribes. (Read more background on the issue here.)

“In granting this stay, the EPA is not agreeing with or adopting the State’s legal or factual arguments concerning the effect of the 1905 Act on the Wind River Indian Reservation boundaries or the potential effects of the EPA’s TAS approval decision,” states the final line of the line.

“EPA is staying the Tribes’ implementation of Clean Air Act planning and monitoring activities in areas challenged by the State of Wyoming and looks forward to the orderly resolution of the Wind River Reservation boundaries in the courts,” McGrath said in a statement. “We are encouraged that this approach will help alleviate tensions in areas of disagreement while providing all parties an opportunity to work together to implement EPA’s decision and ensure environmental protection.”

“This is good news for Wyoming. I asked for this and I appreciate the EPA’s action,” Gov. Matt Mead said in a statement. “We will continue to pursue our challenge in the 10th Circuit Court of Appeals because this stay does not change the Court’s deadlines. This action provides more certainty for all citizens of the state until the Court can rule or the EPA reconsiders its decision.”

The state has petitioned for the EPA ruling to be heard in appeals court. The deadline for filing petitions is Feb. 18. County10.com has not yet received a statement from the Northern Arapaho Tribe.

“Our interest, as is any government’s interest, is for the health, welfare, safety and economic security of all people living within the reservation boundaries,” Shoshone Business Councilman Wes Martel said in a news release.

The statement from the tribes continues: “The EPA’s decision only affirms what we’ve known for over a hundred years. We understand, however, that clarifying these facts creates confusion, and that’s what we’re trying to relieve as we support this partial stay.”

Read the complete letter from the EPA here. Read Eastern Shoshone Tribe’s full statement here.