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How bad is Gulf oil spill? A global Q&A on offshore oil spills

With some 1,200 offshore oil rigs operating today, oil spills are still relatively rare. But experts warn that safety procedures and cleanup methods have not kept pace with drilling at ever-deeper depths.

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Montara, Australia, 2009: An oil well in the Timor Sea, off the coast of Western Australia, began leaking, and the platform subsequently caught fire. The well spewed oil for more than two months, leaking as much as 2,000 barrels a day before it was capped, making it one of the worst spills in Australian history.

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Have cleanup and containment methods improved?

The basic techniques used to contain offshore spills haven't changed much in the past three decades, but spills are now tracked by satellite; containment booms stand up better to waves; skimming technology has improved; and chemical dispersants, used to break up the oil into smaller particles, are now less toxic, though they still have a harmful effect on the environment. In the case of the Deepwater Horizon, dispersants have been pumped into the source of the leak for the first time.

Though methods may have been refined and improved, "the techniques are still basically the same," says Gerald Graham, an oil-spill response expert and president of Worldocean Consulting. Recovery rates – how much of the oil is removed from the ocean – haven't improved, says Dr. Graham. He says they still hover at around 10 percent of the total spill.

Jerome Milgram, a Massachusetts Institute of Technology professor who has extensively studied oil spills, says open-water cleanup is tough to improve. "It's never been particularly effective in open waters, and I don't think it ever will be," he notes. Dr. Milgram, who worked to contain the Ixtoc oil spill, says there hasn't been enough research into subsea containment devices.

Have preventive measures improved?

Offshore oil wells have blowout preventers, valves intended to seal off the well if oil or gas begins to flow uncontrollably. Norway and Brazil require a last-resort backup method called an acoustic switch in case the blowout valve fails. The United States does not require rigs to be equipped with these devices.

Andy Radford, senior policy adviser for offshore issues at the American Petroleum Institute, says questions about the reliability of acoustic switches played a role in the US decision not to require their use. But even if the US had more stringent regulations, enforcement would be difficult, says MIT's Milgram: "I haven't the foggiest idea of how to enforce them. You can't send an inspector down 5,000 feet to check a voltage meter on a battery," he says, referring to allegations of a dead battery on one of the Deepwater Horizon's blowout prevention devices.

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