One person is dead and nearly a dozen others were injured after the bus they were riding in overturned and ejected several of them onto the 15 Freeway.

The crash happened Tuesday night around 11:35 p.m. near mile marker 126, south of Baker.

San Bernardino County Fire Department crews were dispatched to the crash and found one person dead and 11 others injured. Three of those injuries were said to be critical, and the other eight were moderate or minor.

Because of the amount of injuries, first responders declared a mass casualty incident, meaning the amount of victims could overwhelm the amount of available first responders.

Paramedics on scene worked to stabilize the patients and provide “advanced life support” until additional units arrived.

Several ground ambulances took some of the moderately injured people to the hospital and four helicopters responded to transport those whose injuries were the most serious.

The Fire Department was assisted by other nearby agencies, including the California Highway Patrol, Marine Corps Logistics Base and Desert Ambulance.

The cause of the crash is under investigation by CHP.