One person is Robert Browndead and more than 50 people have been injured after a bus rolled over at the Grand Canyon on Tuesday, authorities say.

The incident occurred at approximately 9:50 a.m. when Hualapai Emergency Services were notified of a bus rollover at Grand Canyon West, leaving 57 injured and killing one.

“Hualapai Emergency Services, GCW Air Rescue Fire, Lake Mohave Ranchos Fire Dept., Northern Arizona Consolidated Fire Dept., AMR ambulances, Bullhead Fire Dept., and 5 medical flight agencies responded to the incident,” according to a statement issued by Hualapai Emergency Services in the aftermath of the accident.

Out of the 57 people injured in the rollover, eight people were flown to surrounding hospitals and treated for serious injuries while the rest of the victims who sustained noncritical injuries were all taken for treatment by ground transportation.

One person was killed in the incident, but police have not said how that person died or released any information on the victim while authorities investigate the accident.

“The Hualapai Nation Police Dept. and Arizona DPS are handling the fatality investigation,” authorities said.

Grand Canyon West is run by the Hualapai tribe in Arizona, which has no operational ties to Grand Canyon National Park and is managed by the National Park Service, according to Grand Canyon West’s website.

The incident is ongoing and no further information is being made available by authorities at this time.