A big-rig truck hit a piece of debris on Highway 101 on Wednesday morning and ruptured a diesel tank, spilling all over the northbound freeway lanes near San Ysidro Road and closing the northbound lanes for two hours.
Both lanes were reopened as of 2:40 p.m., Montecito Fire Protection District spokeswoman Geri Ventura said.
A dump truck's tire blew out and the following tanker truck hit it, which punctured a hole in the "saddle tank" holding diesel fuel underneath the truck, according to authorities.
Montecito and Carpinteria-Summerland fire engines were on the scene for several hours stopping the leak and doing cleanup, and the California Highway Patrol closed all northbound lanes between San Ysidro Road and Sheffield Drive from 11 a.m. to about 1:15 p.m.
The spill was estimated at 20 to 30 gallons, and the tractor-trailer rig was parked on the shoulder of the Highway 101 on-ramp at San Ysidro Road.
Firefighters crawled under the truck and whittled down a piece of redwood dowel to plug the leak, said Dr. Peter Hartmann of Urban Hikers.
"There was quite a bit of fuel spilled on the freeway, tracked along by the cars driving by," he said.
Highway 101 was "a mess" in both directions since people saw the traffic and tried to use surface streets, he added.