FILE - In this March 31, 2020, file photo, members of an Arizona National Guard unit pause while loading a helicopter with medical supplies to be taken to the remote Navajo Nation town of Kayenta in Phoenix. The Navajo Nation is ordering all people on the tribe's sprawling reservation to wear protective masks when out in public to help fight the spread of the coronavirus. Tribal officials announced Friday, April 17, that the Navajo Department of Health issued an emergency health order for the reservation, which includes parts of Arizona, New Mexico and Utah. (AP Photo/Ross D. Franklin, File)