After the end of World War II, the United States encouraged uranium mining production because of the nuclear arms race with the Soviet Union, its opponent in the Cold War. Large uranium deposits were found on and near the Navajo Reservation in the Southwest, and private companies hired many Navajo employees to work the mines. Disregarding the known health risks imposed by exposure to uranium, the private companies and the United States Atomic Energy Commission failed to inform the Navajo workers about the dangers and to regulate the mining to minimize contamination. As more data was collected, they were slow to take appropriate action for the workers.