A federal class action lawsuit has been filed against major oil companies including ExxonMobil, Chevron, BP, Shell, ConocoPhillips and several others, alleging they are manufacturing and selling ethanol blended gasoline that damages marine fuel tanks, engines, and other components. Until 2004, gasoline companies widely used Methyl tert-butyl ether as an additive to boost octane, but it was banned in many states due to environmental concerns. The suit alleges that the companies' use of ethanol as a fuel additive corrodes fiberglass marine fuel tanks and damages engines, as well as the marine environment in California.
At that time oil companies selected ethanol, which is particularly harmful in the marine environment, as the replacement additive. Ethanol can dissolve the resin that is used in marine fuel tank construction, destroying the tank, and allowing the dissolved resin to enter the engine via the fuel system, causing damage to the engine and other components. Sources allege that the oil companies know this fuel is corrosive, but intentionally have not informed consumers in order to increase profits.