The visitor center and a wastewater treatment plant were among the 50 to 80 structures lost, the park superintendent said. The area was evacuated Thursday.

Parts of Grand Canyon National Park remained closed to the public Sunday because of wildfires and the release of chlorine gas from a North Rim water-treatment facility, the National Park Service said.

The North Rim was evacuated Thursday because of wildfire and will remain closed for the rest of the season, the park said in a statement.