Tesoro supplied gasoline in violation of state regulations from two Tesoro refineries and one terminal for a period of 52 violation days. Tesoro is the second-largest independent refining and marketing company in the Western US.

In all there were four separate violations by Tesoro. In three cases, Tesoro sold, offered for sale, supplied or offered for supply California gasoline which had either a sulfur content, aromatics content or olefin content exceeding specified limits.

All three —sulfur and the two hydrocarbon compounds— contribute to air pollution, and in each of these cases the violating fuel got into the marketplace. ARB inspectors discovered the three exceedances during a routine sampling inspection. Tesoro cited problems related to its laboratory and said that changes were made to its laboratory procedures to prevent similar violations in the future.

In the fourth incident, at Kinder Morgan’s Concord Terminal, Tesoro incorrectly combined conventional gasoline and CARBOB, or the California Reformulated Gasoline Blendstock for Oxygenate Blending. CARBOB is the blendstock form of gasoline before an oxygenate, such as ethanol, is added to it to make finished gasoline found at gas stations. Tesoro self-disclosed the violation, citing operator error. None of that fuel ever entered the marketplace.

Tesoro fully cooperated with ARB in this matter and took diligent steps to comply, reduce the number of days of violation and prevent recurrence of similar situations. Of the approximately $1 million in penalties, $760,500 will go to the California Air Pollution Control Fund and $253,500 will go to fund the retrofit of California school buses with diesel particulate filters.