A water treatment facility at the North Rim had been compromised by the fire, causing chlorine gas to fall towards the bottom of the canyon.

Police have closed Indian School Road at Maryvale Parkway as the investigation begins. There is no estimated time for the road to reopen.

Here's what's open and closed at Grand Canyon North Rim, South Rim and Phantom Ranch in the wake of wildfires that destroyed the North Rim lodge.

A wildfire on the North Rim of the Grand Canyon has destroyed more than 70 structures, including a historic lodge and a water treatment facility.

A wildfire burning throughout Grand Canyon National Park damaged a water treatment facility on Saturday, causing a chlorine ...

The Dragon Bravo Fire burning on the north rim of the Grand Canyon has triggered a chlorine gas release. This comes as flames reached the water treatment facility.

A wildfire burning in Grand Canyon National Park triggered a chlorine gas leak Saturday afternoon after flames reached a ...

A Grand Canyon water treatment facility located at the North Rim caught fire on Saturday, causing chlorine gas to be released ...