HOUSTON - Exxon Mobil Corp will soon start trucking crude from two California storage tanks because the company has no other means to empty them since the shutdown of an oil pipeline that ruptured last May and fouled Santa Barbara County shores. Santa Barbara County planners on Monday granted Exxon an emergency permit to fill trucks with crude from the tanks at its Los Flores Canyon facility and transport it to other pipelines. The permit said Plains All American Pipeline LP’s Line 901 is expected to be inoperable “in excess of or at least six months” this year, and Exxon needed another way to remove oil from the tanks for safety reasons. The tanks now hold a combined 425,000 barrels of crude when they usually contain a minimum of 50,000 barrels each when the Plains line operates normally. With Line 901 shut down since the breach last year, Exxon cannot otherwise empty the tanks. Leaving them full risks “catastrophic failure” of leaks if there are any fires, floods or earthquakes, the permit said. The permit will allow Exxon to load the stored oil into trucks, each able to hold about 150 barrels, and move most of it to a Plains pipeline hub in Kern County and another pipeline connected to Phillips 66’s Santa Maria refinery in Arroyo Grande. It will take three to six weeks to empty the tanks with no more than 30 truck trips per day, the county said. Line 901 moved crude produced in Exxon’s Santa Ynez offshore oilfield from Los Flores north along the California coastline to Gaviota.