In a remote reach of the Gulf of Mexico, nearly 200 miles from shore, a floating oil platform thrusts its tentacles deep into the ocean like a giant steel octopus.

The $3 billion rig, called Perdido, can pump oil from dozens of wells nearly two miles under the sea while simultaneously drilling new ones. It is part of a wave of ultra-deep platforms  all far more sophisticated than the rig that was used to drill the ill-fated BP well that blew up in April. These platforms have sprung up far from shore and have pushed the frontiers of technology in the gulf, a region that now accounts for a quarter of the nation’s oil output.

Major offshore accidents are not common. But whether through equipment failure or human error, the risks increase as the rigs get larger and more complicated.

Yet even as regulators investigate the causes of the Deepwater Horizon disaster, the broader dangers posed by the industry’s push into deeper waters have gone largely unscrutinized.