The California Highway Patrol says driver error caused a Forest Service van to plunge over 200 feet down a cliff in the San Bernardino Mountains.
Eight firefighters were injured in Monday's crash near Big Bear Lake.
Thirty-one-year-old Stanley Taylor Jr. was driving the van and the CHP says he may be ticketed for making an "unsafe turning movement."
An investigation finds Taylor was going about 40 miles an hour when he swiped a guardrail while turning. He locked up the brakes, sending the 8-ton van down the mountainside.
The van split apart, with the crew cabin separating from the cab and chassis.
Both pieces stopped about 235 feet below Highway 18.
All eight firemen were wearing seat belts.