The San Francisco-based oil company said it is closing the 73-year-old operation because it had become "uneconomic." Chevron said it will close the refinery in the next several months. The 38 employees at the 26,000-barrel-per-day refinery will be offered other employment in Chevron's expanding operations in the area or a severance package, the company said. Chevron has refined petroleum at the 53-acre site since 1912. The decreased availability of the light crude that the refinery was designed to process contributed to the plant's demise, according to refinery manager Roger M. Maddaford.