Updated at 7:00 p.m. with a correction.

Sen. Bill Nelson, D-Fla., is requesting acting Interior Department Inspector General Mary Kendall to investigate whether oil and gas companies had undue influence on federal regulations overseeing backup systems to cap underwater wells.

Nelson, in a letter today to Kendall, notes that the department's Minerals Management Service did not require "oil rigs... to have audio control devices capable of remotely activating a wellhead's blowout preventer." He is seeking details on how MMS reviewed and finalized rules for blowout preventers and well controls. "I ask that you determine in your investigation the extent to which the oil and natural gas industry exercised influence in the agency's rulemaking process," Nelson wrote.

At least two other major countries that permit offshore drilling require oil rigs to carry audio control devices for the blowout preventer, Nelson said, also referencing reports that regulators may not have acted on concerns that drilling safety equipment may not function in deep waters.

BP CEO Tony Hayward this morning told National Public Radio that the failure of the blowout preventer to contain oil from leaking from the Deepwater Horizon oil rig was "unprecedented." He called it the "ultimate safety system on any rig, and there is no precedent for them failing." The failure of the device has caused thousands of barrels of oil to continue to spill daily into the Gulf of Mexico.

BP officials are still hoping to deploy the blowout preventer using remotely controlled submarines, and Hayward said the plan is to have a containment dome channeling oil to the surface as a way of better controlling it at the site by next weekend. Interior Secretary Ken Salazar said Sunday it could take BP up to 90 days to finish a third option of drilling a well to stem the leak.

The request by Nelson comes as Florida lawmakers are continuing their offensive against plans to expand offshore drilling in the wake of the spill and further complicating hopes of getting major climate and energy legislation through Congress this year.

Ten Florida House members -- led by Democrat Kathy Castor and Republican Bill Young -- sent a letter to President Obama today asking him to reconsider his recent blueprint to expand offshore drilling, including closer to their state's coastline. "Oil company claims that drilling is completely safe now ring hollow," the lawmakers wrote. The lawmakers want the administration to keep intact a 2006 congressional agreement that included a 235-mile buffer off Florida's western coast. "This spill represents a game-changer for Florida," they wrote. The other signers of the letter are Democratic Reps. Debbie Wasserman Schultz, Corrine Brown, Alcee Hastings, Ted Deutch, Alan Grayson, Kendrick Meek, Suzanne Kosmas and Republican Ileana Ros-Lehtinen.

Obama has said he is standing behind the administration's plans to expand drilling along the East Coast, in the eastern Gulf of Mexico and parts of the Alaskan Arctic region and coast.

The issue further complicates Senate climate and energy talks already on the ropes this year due to a dispute between Senate Majority Leader Harry Reid, D-Nev., and Sen. Lindsey Graham, R-S.C. Graham has left the climate talks for the moment due to the push by Reid and Democratic leaders to bring immigration reform up for debate this year. As Reid's and Graham's positions have appeared to harden, so too has the opposition to expanded drilling from coastal-state Democrats in the wake of the rig accident.

Graham this weekend said the administration's plans to expand oil and gas drilling should be preserved despite the continuing oil spill. Expansion of drilling would be vital to preserving any support from Graham and several needed centrists in both parties for a combined carbon pricing and energy production plan Graham and Sens. John Kerry, D-Mass., and Joe Lieberman, I/D-Conn., are spearheading.

Reid on Friday acknowledged that the oil rig spill "will, undoubtedly, require us to re-examine how we extract our nation's offshore energy resources and will have to be taken into consideration with any legislation that proposes to open new areas to development."

Correction: Rep. Kathy Castor, D-Fla., was misidentified in the original version of this post.

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