Customers who bought premium gasoline from Los Angeles-area Mobil stations in recent months may have gotten a little less oomph in their tanks than usual.
Government inspectors are investigating possible glitches in the mixing of ethanol with gasoline at Exxon Mobil Corp.'s terminal in Vernon. Fuel experts say octane levels in high-test fuel distributed from the terminal could have been degraded, although probably not enough to take the gas below the 91-octane minimum for premium.
The episode illustrates the complexities and the potential for problems as California refiners and distributors switch to ethanol from the additive MTBE as a smog-reducing agent. MTBE, which pollutes groundwater, will be banned from California gas next year.
Last month, for example, a miscue resulted in ethanol being left out entirely from 420,000 gallons of regular gasoline distributed from Arco's terminal in San Diego. The company had to retrieve the fuel from 59 stations and re-blend it, leaving some stations without regular gas for a few days.
By all accounts, the Mobil case wasn't as severe. The investigation began in early April, when two Mobil dealers complained that they were shorted on tanks of fuel from the Vernon terminal, said Jeff Humphreys, deputy director of the Los Angeles County Office of Weights and Measures.
Inspectors conducted tests and then shut down three of the terminal's 12 gasoline-dispensing systems because they gave out significantly less fuel than indicated by the meters, Humphreys said.
Humphreys said his agency was looking into the possibility that the pumps that add ethanol malfunctioned, putting less ethanol into the mix and lowering the total volume of the fuel that ended up in the delivery trucks. That would reduce octane levels, industry experts said, because ethanol acts as an octane booster in addition to helping create cleaner-burning fuel.
A person familiar with the situation said trucks drove away light by 150 to 200 gallons, or up to 2% short for a typical 9,000-gallon tanker load. The person added that the blame probably rests with the ethanol nozzles and that the problem dates back to the beginning of the year, when Vernon's bays were retrofitted to dispense ethanol.
California rules require gasoline blends to contain 5.7% ethanol by volume. If an entire volume deficit consists of missing ethanol, the person said, "that calls into question the integrity of the blend and the octane rating."
