Obama administration officials banned mining across one million acres of the most uranium rich land in the United States for 20 years using questionable science to back up their claims that uranium production would adversely affect the environment.

That’s according to key Republicans on the House Natural Resources Committee, which has released internal emails from government scientists stating that some environmental impacts were “grossly overestimated” and “very minor to negligible.” “These emails raise serious concerns about whether the Obama administration’s decision to block uranium production in Arizona was based on politics rather than sound science,” said Rep. Doc Hastings (R-Wash.), chairman of the House Natural Resources Committee.