The giant concrete dome which experts hope can catch oil leaking into the Gulf of Mexico has been lowered into the water (pic right).

BP was leasing the Deepwater Horizon rig when it exploded and sank, causing leaks to spring in the exploratory well it was drilling. The company now hopes the 100 tonne dome will trap oil coming from the seafloor so it can be pumped to the surface for recovery. However, the oil company’s chief executive Tony Hayward warned that it might well not work. “It’s only one of the battle fronts,” he said (NY Times).

The National Oceanic and Atmospheric Administration has confirmed that oil from the accident is now coming ashore on the Chandeleur Islands off the Louisiana coast (BBC). Coast Guard Petty Officer David Mosley said the oil hitting Freemason Island was a “sheen, not the heavier oil” (AOL).

NOAA has diverted one of its research ships to the spill area to collect pollution data.

Policy fallout from the accident also continues, as Interior Secretary Ken Salazar announced that no new offshore drilling permits would be issued until investigations into the Deepwater incident were completed (SF Chronicle). “Salazar’s decision could prolong the waiting game for Shell as it prepares to move ahead with Arctic drilling in July. The drilling cannot proceed without the permit, which Salazar could still grant after the spill investigation ends, or which he could deny, citing environmental risks,” notes the LA Times’s Greenspace blog.

Meanwhile, it’s almost possible to feel sorry for the Minerals Management Agency, which is supposed to oversee drilling:

A Wall Street Journal examination of the MMS’s track record found several instances of the agency identifying potential safety problems and then either not requiring follow-up or relying on the industry to craft a solution.

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Oil rig operators generally are required to submit a detailed “blowout scenario.” But the federal Minerals Management Service issued a notice in 2008 that exempted some drilling projects in the Gulf under certain conditions. BP met those conditions, according to MMS, and as a result, the oil company had no plan written specifically for the Deepwater Horizon project, an Associated Press review of government and industry documents found.

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For more than a decade, the Minerals Management Service, a federal agency within the interior department, has been accused by government watchdogs of failing to inspect offshore oil leases and relying too heavily on industry data in collecting royalties and other fees related to oil and gas. In a low point for the agency, a scathing 2008 report by the inspector-general of the interior described a culture of “substance abuse and promiscuity” within the MMS department charged with collecting royalties on leases and revealed that two MMS employees had, literally, been in bed with industry contacts. (Financial Times.)

Video: remotely operated underwater vehicle prepares to stop leak, 3 May.

Image: mobile offshore drilling unit Q4000 lowers pollution containment chamber into the sea on 6 May.