Federal investigators have said that they haven't found physical evidence confirming a witness' claim that a FedEx truck was on fire before it slammed into a bus carrying high school students, killing 10 people in Northern California.
National Transportation Safety Board member Mark Rosekind said that investigators are not ruling out a pre-impact fire, but a fire specialist did not find evidence of flames as the truck crossed a median, sideswiped a Nissan Altima and crashed into the bus.
"This is all preliminary and factual information," Rosekind said at a news conference. "We are not ruling anything out."
The bus was carrying Southern California high school students to a campus tour of Humboldt State University. Five students, three adult chaperones and both drivers died in Thursday's collision in Orland, a small city about 100 miles (160 kilometers) north of Sacramento. Dozens were injured with cuts and burns.
The driver of the Altima, who survived with minor injuries, told investigators and reporters Saturday that she had seen flames emerging from the lower rear of the truck's cab as it approached her car. The bus was gutted and the truck was a mangled mess after an explosion sent flames towering and black smoke billowing, making it difficult for investigators to track the source of the fire.
Rosekind said a blood test of the FedEx truck driver could indicate whether he inhaled smoke before his death. A family member told the Sacramento Bee that the truck driver was Tim Evans, 32, of Elk Grove, California.
The biggest questions for investigators include why the truck had left its lane and left no tire marks, suggesting the driver did not brake. The investigation will review maintenance records and the driver's medical history, experience and potential impairment.
The bus' black box-style electronic control module was recovered and will be analysed. The truck's device was destroyed, but other steps will be taken to analyse its speed and maneuvering.
Beyond the cause of the crash, the NTSB will examine if any of its safety recommendations would have reduced the death and injury toll.
In this case, the transportation authorities are focusing on seatbelts and fire safety, though it has no authority to enforce measures it recommends.
