At least eight firefighters were hurt when a fire truck crashed on a freeway near Irvine, California, Thursday night, authorities said. 

The Orange County Fire Authority truck overturned on State Route 241 at about 6:50 p.m. local time in the Portola Springs area near State Route 133, according to California Highway Patrol. 

A ladder in the roadway caused the fire truck and another vehicle in front of it to swerve, highway patrol said, and the truck collided with a nearby guard rail and overturned. It did not appear that any other vehicles were involved. 

Initially, highway patrol reported that 12 firefighters were injured, but late downgraded that to eight. Six suffered serious injuries and two minor injuries, highway patrol said. 

Helicopters landed on the highway, which is a toll road, and airlifted the victims to area hospitals.

CHP officers issued a five-hour closure of the freeway’s northbound lanes shortly after the crash. 

Video from the collision site showed the crashed vehicle with an “Orange County Fire Authority Santiago Hand Crew” decal. Highway patrol said the firefighters had been battling the massive Airport Fire prior to the crash. 

This is a developing story. Check back for more details.