The oil well spewing crude into the Gulf of Mexico didn't have a remote-control shut-off switch used in two other major oil-producing nations as last-resort protection against underwater spills.
The lack of the device, called an acoustic switch, could amplify concerns over the environmental impact of offshore drilling after the explosion and sinking of the Deepwater Horizon rig last week.
...U.S. regulators don't mandate use of the remote-control device on offshore rigs, and the Deepwater Horizon, hired by oil giant BP PLC, didn't have one. With the remote control, a crew can attempt to trigger an underwater valve that shuts down the well even if the oil rig itself is damaged or evacuated.
...The U.S. considered requiring a remote-controlled shut-off mechanism several years ago, but drilling companies questioned its cost and effectiveness, according to the agency overseeing offshore drilling. The agency, the Interior Department's Minerals Management Service, says it decided the remote device wasn't needed because rigs had other back-up plans to cut off a well.
...An acoustic trigger costs about $500,000, industry officials said. The Deepwater Horizon had a replacement cost of about $560 million, and BP says it is spending $6 million a day to battle the oil spill. On Wednesday, crews set fire to part of the oil spill in an attempt to limit environmental damage.
Some major oil companies, including Royal Dutch Shell PLC and France's Total SA, sometimes use the device even where regulators don't call for it.