A bus carrying teenagers back from a camp overturned on a Southern California highway, resulting in 20 people being hospitalized, authorities reported on Monday.

The incident involved 36 passengers and occurred just before 9 p.m. on Sunday along State Route 330 near Running Springs, roughly 70 miles northeast of Los Angeles.

The San Bernardino County Fire Department noted that several passengers managed to exit the overturned bus using a roof hatch.

An image from the San Bernardino County Fire Department showed the overturned bus on the highway near Running Springs, California.

“A total of 26 individuals received medical attention, with three sustaining major injuries,” the agency stated. “Of those, 20 were transported to nearby hospitals via ground ambulances. The remainder of the occupants declined further medical treatment or transportation by emergency services.”

The passengers, a mix of adults and teens, were traveling downhill on the way home to Orange County after attending a camp in the San Bernardino Mountains near Angelus Oaks, the department said. 

A bus overturned on a California road carrying 36 people.  (San Bernardino County Fire Department)

The response included 11 fire engine companies, 11 ambulances and four chief officers to the scene, the department said. 

The first patients were en route to a hospital within 15 minutes of crews responding.  

The hatch where passengers on an overturned bus escaped. 

The California Highway Patrol is leading the investigation into the incident. 

The road was closed in both directions during the investigation at the scene. There was no fire or hazardous material exposure, the fire department said.