WASHINGTON  The Interior Department said Monday that it had approved the first new deepwater drilling permit in the Gulf of Mexico since the BP explosion and spill last spring, a milestone after a period of intense uncertainty for industry and a wholesale remaking of the nation’s system of offshore oil and gas regulation.

Michael R. Bromwich, director of the Bureau of Ocean Energy Management, Regulation and Enforcement, said that Noble Energy had been granted permission to resume drilling in 6,500 feet of water off the coast of Louisiana.

Work on the well was suspended, along with virtually all other drilling activity in water deeper than 5,000 feet, immediately after the Deepwater Horizon accident last April 20. The disaster killed 11 rig workers and spewed nearly five million barrels of oil into the ocean.

Still, there was no indication that drilling in the gulf would return anytime soon to levels preceding the BP well blowout.