Oil companies are looking to save millions of dollars in costs by leaving oil platform towers in place in the Pacific Ocean off the California coast to serve as artificial reefs instead of paying to remove them, as required under state and federal law. California state Sen. Dede Alpert (D) is sponsoring a bill that would let the underwater steel structures stay put after oil platforms are decommissioned, while requiring oil companies to contribute money to a marine research endowment fund. Invertebrates such as mussels and barnacles attach themselves to the structures, and a number of other sea creatures gather around them. Some 100 oil rigs in the Gulf of Mexico off the coasts of Louisiana and Texas have been left to serve as artificial reefs. Many environmentalists accuse oil companies of simply trying to weasel out of costly cleanups.