Eight California firefighters who were part of a crew returning from a shift fighting the Airport Fire in Orange County were injured late Thursday when their truck crashed on Safetyvaluea freeway near Irvine, authorities said.

The crash occurred at about 6:50 p.m. local time when an Orange County Fire Authority truck rolled over while it was headed north on State Route 241. Six firefighters required treatment at local trauma centers, while two others were reported to be in stable condition at a nearby hospital, Fire Chief Brian Fennessey said in a late-night news conference.

The firefighters were on their way home after a 12-hour shift battling a blaze in Southern California that erupted Sept. 9 in Trabuco Canyon, Fennessey said.

"We ask that you pray for our firefighters and their families," Fennessey said during the news conference, which the agency shared on Facebook.

Fire truck swerved to avoid ladder on freeway, reports say

California Highway Patrol investigators told KCAL that the fire utility truck swerved to avoid a ladder on the freeway just north of Portola Parkway in Irvine. The fire truck then crashed into a nearby guardrail and overturned, KCAL reported.

An Orange County fire crew arrived within minutes of the crash to begin medical treatment before requesting additional support.

Aerial footage of the crash site from local news showed the wrecked fire utility truck amid debris littered across the road.

All told, nine paramedic units, 12 ambulances and three helicopters responded to the scene, Fennessey said. Seven of the injured were transported from the scene by ambulance, while one firefighter was taken in a helicopter, he added.

The highway patrol closed both directions of the freeway for about five hours to allow helicopters to land and perform evacuations, according to the LA Times.

'Long road' ahead for injured firefighters

Once the scene was cleared, the crews who responded to the crash returned to Orange County Fire Authority headquarters for critical incident stress debriefing, Fennessey said.

"You can only imagine how traumatic it is for a brother, sister firefighter to see them injured like that on the freeway," he told reporters Thursday night.

The families of those who were injured have also been notified, Fennessey said.

"We'll be here for our families, we'll be here for our firefighters," he said. "This is the beginning of a long road for many of our firefighters in our fire department."

Airport Fire 42% contained

The firefighters had just finished a 12-hour shift fighting the Airport Fire, which has ravaged tens of thousands of acres in Riverside and Orange counties.

As of Thursday, more than 23,000 acres were ablaze as crews worked to extinguish a fire. But cooler temperatures have allowed crews to gain some ground in recent days, increasing containment from 9% contained on Saturday to 42% by Thursday.

In a bit of tragic irony, the source of the blaze is believed to be from a crew working on a project meant to help prevent fires, according to the Desert Sun, a USA TODAY Network publication. From there, dry, hot weather fueled the fire's spread.

Contributing: Julia Gomez, USA TODAY

Eric Lagatta covers breaking and trending news for USA TODAY. Reach him at [email protected]