Orland, CA- A head-on collision on California between Fed Ex truck and a chartered bus, carrying high school students, left caused a fiery explosion and left ten people dead.

The accident happened at 5:30 local time on Interstate 5 outside of Orland as a bus load of teens was headed back to Los Angeles after visiting Humboldt State University’s Spring Preview Day, according to the Los Angeles Times.

The chartered bus and the Fed Ex tractor-trailer were on opposite sides of the freeway when from some yet unknown reason, the truck crossed over the grassy median and slammed head-on into the bus. Both vehicles ignited in a fiery blaze which was still burning furiously when emergency crews arrived.

Another vehicle was involved in the crash, though police did not elaborate how. The two occupants suffered minor injuries and were treated at the scene.

“I went outside, and everything was in flames already,” a local resident, Luis Lopez, told CNN affiliate KXTV. “There were a couple of explosions after that.”

One witness described seeing one of the victims engulfed in flames as he was running away from the wreckage.

Students on the bus had to bust out the back windows to get out of the fiery wreckage.

The fire killed ten people, including five students and both drivers, and left dozens with minor to serious injuries. Nine people were pronounced dead at the scene and one died later of severe burns according to the Los Angeles Times.

Police are now going through the painful task of identifying the fatal victims through dental records or DNA testing. The names of all the victims will be released after police identify the victims and notify their families.

One victim has been identified as 26 year-old Arthur Arzola, an admissions counselor at Humboldt.

Thirty-one victims were taken to several hospitals in the area with personal injuries ranging from minor to critical. Injuries include varying degree burns, broken limbs and minor cuts and bruises.

“The great irony here, the great sadness, is these are the students California needs to be successful going forward,” CSU Chancellor Timothy White said in statement, adding the deceased students “had their dream of going to Humboldt State taken away by this tragic accident.”

On Friday, local law enforcement and investigators from the National Traffic Safety Board combed through the wreckage of the burnt out shells of both vehicles. Investigators said it could take months for them to conduct their investigation and determine exactly what happened.

Part of the investigation will entail trying to determine why the truck drivers crossed the median. Some initial reports indicated that he may have been trying to avoid colliding with a car that had been involved in a previous accident. Police also said it is possible he fell asleep at the wheel or whether he experienced a mechanical failure of some sort.

Investigators will also examine whether road conditions at that the time had any bearing in the tragic accident.