A uranium producer has agreed to temporarily pause the transport of the mineral through the Navajo Nation after the tribe raised concerns about the possible effects that it could have on the reservation.

Gov. Katie Hobbs said Friday that she intervened this week after talking with Navajo President Buu Nygren, who had come up with a plan to test a tribal law that bans uranium from being transported on its land.

Energy Fuels isn’t legally required to give advance notice. But the Navajo Nation, the U.S. Forest Service, county officials and others says the company verbally agreed to do so — and then reneged on the promise Tuesday.

Mining during World War II and the Cold War left a legacy of death, disease and contamination on the Navajo Nation and in other communities across the country. The Havasupai tribe is among the tribes and environmentalists that have raised concerns about potential water contamination.