Nelson seeks probe of industry influence over offshore rig safety rules

“At least two other major countries that permit offshore drilling require rigs to carry such devices. Also, newly published accounts indicate regulators didn’t act on other concerns that oil-drilling safety equipment may not function in a deep-water environment,” Nelson’s letter notes.

The letter asks the IG to review the way MMS crafted regulations for offshore oil rig operation. “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,” the letter states.

The blowout preventer includes devices – called shear rams – that are supposed to pinch off well pipes when accidents occur to prevent uncontrolled releases like what’s now occurring in the Gulf.

The Wall Street Journal on Monday looked at the role of the blowout preventer in the spill resulting from the April 20 explosion at the Deepwater Horizon rig, which is owned and operated by Transocean Ltd. and leased to oil giant BP. The device did not deploy, which BP CEO Tony Hayward on Monday called an "unprecedented" failure.

“Investigators are expected to focus on whether the blowout preventer received a signal from workers on the rig. The Deepwater Horizon wasn't equipped with a backup remote trigger that is a common drill-rig requirement in other oil-producing nations, but not the U.S. If the blowout preventer did receive the signal, experts say, a critical question is why the rams didn't seal off the well,” notes the Wall Street Journal piece.

The story also notes that a 2004 study that MMS commissioned raised questions about the ability of shear rams to cut through the strong pipes used in deepwater wells.