UPDATE (7:22 p.m.): The California Highway Patrol says 32-year-old Jesse Villasana of Wasco, CA was driving a Western semi-truck with an attached trailer on SR-166 when he entered into a left-bound roadway and the trailer started swinging from side to side.

Officials say Villasana tried to correct its path by making a hard turn to the left when the trailer disconnected itself.

The trailer, carrying crude oil, then rolled down the embankment into the creek bed, according to the CHP.

Officers say the trailer was carrying 6,000 gallons of crude oil and a visual estimate determined half of the oil was emptied into the creek.

The CHP says once the trailer is pumped out of remaining oil, they will know how for sure how much was emptied.

Drugs and alcohol were not determined to be factors in this incident.

The California Department of Fish and Wildlife and the Santa Barbara County Fire Department are overseeing clean-up.

It's estimated clean-up efforts will take about two weeks.

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ORIGINAL STORY: The Santa Barbara County Fire Department is responding to an oil tanker that has overturned, spilling 6,000 gallons of crude oil into the Cuyama River Saturday morning.

According to the Santa Barbara County Fire Department, the incident occurred shortly after 6 a.m. Saturday on Highway 166.

Officials say the driver of the oil tanker was not injured.

The fire department says CHP, Santa Barbara City Fire Department, Caltrans, U.S. Fish and Wildlife Service and a cleanup company are assisting with mitigation and cleanup.