LAKE FOREST – County firefighters spent more than an hour Wednesday morning freeing a man’s arm from the back of a dump truck in the 20700 block of Linear Lane, fire Capt. Larry Kurtz said.

The man, in his 40s, was working at the back of the rig when the container, which sits atop a sliding rail, slid for unknown reasons and pinned his arm between the container and slide rail around 9:15 a.m.

He was conscious and talking to rescuers as 20 firefighters worked to free his arm, Kurtz said. Meanwhile, a truck driver was working to keep the rig from moving.

The man’s arm was freed at about 10:25 a.m. (Orange County Fire Authority firefighters are paramedics as well).

Traffic was blocked at Linear Lane and Dimension Drive to create a landing zone for a Mercy Air helicopter. The man was airlifted at 10:30 a.m. and flown to UCI Medical Center in Orange.

The truck was from Sepulveda Building Materials, which specializes in decorative boulders and masonry supplies. It was hauling about 23 tons of building material.

Cal/OSHA, a state agency, will investigate the cause of the incident.

Contact the writer: 714-796-7802 or jsudock@scng.com