At least eight cars and four locomotives derailed following the crash near the city of Madera at around 6:15 a.m, according to Burlington Northern Santa Fe Railway officials.

"One train that had originated in Richmond with a destination of Barstow collided with a train that had originated in San Bernadino and was heading up toward the Richmond area," railway spokeswoman Lena Kent told KCBS.

The injured rail workers were hospitalized.   One is in critical condition, another in serious condition, and three others suffered minor injuries. There were reports that the workers jumped from the freight cars moments before the collision. 

The trains were going in opposite directions on the same track.  Burlington Northern Santa Fe Railway officials, California Department of Forestry and Fire Protection representatives, among other local agencies, are investigating the collision and assessing the damage.

One train was carrying cement, and the other was carrying a flammable liquid that officials believe did not leak into nearby water-ways.   Environmental and health officials are trying to determine if any of the chemicals leaked into the soil.  Several orchards and canals are adjacent to the area where the crash took place near the town of Berenda north of the city of Madera.

"There is some diesel fuel leaking from the locomotive and it is unclear if there is any hazardous material leaking from the cars," Kent said.

It's unclear if both of the trains were moving at the time of the crash. 

The San Joaquins Amtrak service, which uses the same track as the freight trains, has suspended its train service in the area and is using a bus bridge for its passengers.