Brazil Says Chevron Oil Leak Larger Than Estimated Brazil's oil regulator says Chevron Corp. could have prevented an offshore oil leak last year. It also says the leak was larger than previously estimated. Magda Chambriard says the National Petroleum Agency she heads has concluded its investigation into Chevron's leak off the Rio de Janeiro state coast in November and a second smaller leak in March. Chambriard says the study determined that about 155,000 gallons seeped into the sea from cracks on the ocean floor near a Chevron wellhead. Previous estimates put it at 110,000 gallons. She says the agency is still determining the fines Chevron will face. But she adds it's likely to be near the maximum allowed under Brazilian law - $25 million total. Chevron says it will comment soon on the regulator's findings.