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 blazes have consumed about 45,000 acres of land, an area about the size of Washington, D.C. Park officials said the Dragon Bravo Fire, which has burned 5,000 acres within the park, destroyed dozens of structures including the Grand Canyon Lodge,