Tesoro discovered the spill at 11:30 a.m., December 15, 2005.
Tesoro estimates approximately 1 barrel (42 gallons) of Vacuum Tower Bottom Blend (VTBB) was spilled. VTBB is a residual oil product that is not processed at the Tesoro refinery. VTBB has a thick consistency, similar to asphalt.
Tesoro’s twenty-inch transfer line failed. The line was not pressurized to transfer product at the time of the discharge but contained residual VTBB. The exact cause of the line failure is being investigated by Tesoro personnel.