Oil and water

Among the endangered species on our coast, count California’s 27 offshore oil rigs. Even as other states lobby for expanded drilling, President Obama has left a federal moratorium on Pacific Coast drilling intact — meaning that within 20 years, the existing rigs will probably vanish as the wells they’re tapping dry up. Yet while the unsightly and environmentally risky platforms are destined to be scrapped, what will remain underwater is very much in question.

As Times staff writer Jack Dolan reported Sunday, a bill is sailing through the Legislature that would allow oil companies to remove only the top part of the rigs, leaving the rest — up to a depth of 85 feet — standing. The bill, which was written by Assembly Speaker John A. Perez (D-Los Angeles) and has passed his house by a unanimous vote, seems on paper to be a win for the oil companies, the state treasury, fishermen and even the ocean ecosystem. But like those underwater pilings that could remain in place for centuries, it’s what’s below the surface that’s worrisome.

Oil companies would save an estimated $650 million by leaving the rigs’ bases alone. Under the bill, they would get to keep half those savings, with the rest split among the state general fund, a new environmental trust and the counties whose coastlines are closest to the shuttered rigs. The pilings that remain would serve as artificial reefs, continuing to support the community of marine organisms that already inhabit them.

So what’s to fret about? For one thing, shell mounds — piles of mud, sludge and organic debris such as barnacles and mussel shells that have dropped off the rigs and accumulated on the ocean floor. The mounds haven’t been adequately studied, though a report by the State Lands Commission after Chevron removed four rigs off Santa Barbara County in 1996 found that the mounds contained heavy metals and toxic chemicals, in addition to posing a navigation hazard. Under the bill, AB 2503, those mounds would stay. There are also serious questions about liability. It’s unclear whether the state could be sued if, say, commercial fishermen snag their gear on the underwater platforms, or other problems arise.

The so-called rigs to reefs plan could be a good deal for just about everybody, but although it has been around for quite a while — former Gov. Gray Davis vetoed a similar bill in 2001 on the grounds that there was no evidence it would benefit marine life — there has been distressingly little study of its environmental or legal impacts. Given that no rigs are expected to be decommissioned before 2015, there’s no pressing need to pass the bill now. The scheme could benefit from a little more scrutiny.