Accident forces motorists to find a detour Friday morning.

UPDATED FRIDAY 12:33 p.m. 

The southbound lanes of I-5 are now open after being closed from the Kern County line to Castaic as crews cleaned up a hazardous chemical spill near Fort Tejon.

According to Officer Mark Ehly of the CHP, a big rig traveling southbound just north of Fort Tejon was observed to be leaking chemicals from its load. Drivers in the area alerted the big rig driver, who pulled off the freeway into a large dirt area just south of the landmark.

Because of the number of potentially combustible and hazardous chemical tanks in the driver's load and because it could not immediately be determined which tank was leaking, Caltrans officials closed all southbound lanes for several hours Friday morning.

"The leak appears to be only about five gallons and the driver thinks it is one of the least dangerous of the chemicals," Ehly said. "But there are several different containers on the truck and we need to ascertain which one is leaking and make sure none of the others are affected."

Kern County Fire Hazmat and Health Department officials were on the scene, along with CHP and Caltrans cleanup crews.