On the same day Sen. Dianne Feinstein chastised Chevron Corp. for keeping an 800,000-gallon spill outside Bakersfield “under wraps,” California officials confirmed Thursday that the site was once again seeping a hazardous mix of oil and water. The new leakage occurred in a surface expression vent in the Cymric oil field, near the Kern County town of McKittrick, according to the state Division of Oil, Gas and Geothermal Resources. The vent is one of the locations where three previous leaks released about 800,000 gallons of oil and water.