"The wellhead remained secure, no flow was detected, and there were no injuries." Oil spill experts said the incident highlights the risks even routine operations can pose offshore. "BOPs have been fitted on wellheads thousands of times in the Gulf and elsewhere, most without incident," said Rick Steiner, a marine conservationist and former professor at the University of Alaska, whose background includes advising on the response to the Deepwater Horizon, the Exxon Valdez, and many other oil spills worldwide. "But the Shell/Transocean mishap shows that simple failures can cause serious incidents, in the blink of an eye." Steiner called for an in-depth investigation by the Bureau of Safety and Environmental Enforcement (BSEE), which regulates the offshore oil industry. "While it is reported that the riser broke above the flex joint, BSEE must fully investigate this mishap and come to its own credible conclusion," Steiner added, referring to details reported by Rig Lynx. "What exactly caused the riser to break?"