Boat owners might unknowingly risk serious harm to the boat engine by using ethanol-blended gasoline.

Investigation and pending class action lawsuit against Exxon Mobile, Chevron, Royal Dutch Shell, Conoco Philips, Valero Energy. Teseoro an BP in which owners of boats with fiberglass fuel tanks who use ethanol-blended gasoline allege that Exxon Mobile, Chevron, Royal Dutch Shell, Conoco Philips, Valero Energy. Teseoro an BP use of ethanol as an additive to their fuel causes damage to engines, and spreads pollution to marine life in California.

For example, Barry Treahy spent months working on his boat. He kept changing her fuel filters. Then he rebuilt her carburetor. Finally, he cut into her gas tank, cleaned out the mysterious caramel-colored gunk and patched her up -- twice. Disaster struck on a summer day in San Diego, when Treahy's beloved 20-foot fishing boat was parked street side with the outer hull plug open to drain any residual water. The boat's 55-gallon gas tank failed and gasoline streamed into the bilge and down the street. "I wasn't smart enough to figure it out at first," Treahy said of Sally Ann's chronic troubles.

Finally, he found the answer in a boating magazine. Ethanol-laced gasoline was dissolving his boat's fiberglass fuel tank, sending bits of resin to clog filters and ultimately eating a hole all the way through the tank. Years of adding ethanol to gasoline to reduce air pollution and foreign oil dependence has had a nasty side effect: The stuff appears to damage boat fuel tanks made of fiberglass. And California is a floating testing ground for the ethanol effect. At the beginning of 2004, all gasoline sold in the state was required to carry 5.7% ethanol as a replacement for the banned fuel additive methyl tertiary butyl ether, or MTBE, which was fouling groundwater supplies.

Some boaters were unaware of the ramifications of the switch. Lawrence Turner, stuck with more than $35,000 in ethanol-related damage to his boat, decided to fight back. Last week, the Studio City resident sued Chevron Corp., Exxon Mobil Corp. and eight other gasoline producers and distributors in U.S. District Court, arguing that the companies sold gasoline at marinas without warning boaters of ethanol's harmful consequences. "It caught me completely by surprise," said Turner, whose twin-engine, semi-custom Mediterranean sport fisher named Grateful Med is still out of commission. "I figured if you went to a marine gas station and filled up your tank, you were fine to operate." Ethanol-blended fuel destroyed the boat's fiberglass fuel tank, and mechanics had to cut through the hull and remove the ruined tank piece by piece. A new, aluminum tank was being installed last week. Engine repairs are still to come. "As I reflected on the situation, I thought about the fact that there were never any warnings from the fuel companies that the product they were selling could damage the tank that it was going into," said Turner, a 50-year-old accountant, attorney and diet company president. "What if people pulled up to their local gas station [in their cars] and all of the sudden their gas tank started dissolving."

The class action complaint alleges that the oil companies know this fuel is corrosive, but they're keeping consumers in the dark to pump up their profits. The cost to the consumer is thousands of dollars in repairs.