CSM: “Government regulators have said that the failure of the Deepwater Horizon’s blowout preventer April 20 was unforeseeable. But studies conducted for federal regulators in MMS or with their participation show that blowout preventers were known to have ‘safety critical’ vulnerabilities. The federal agency charged with setting safety standards for offshore oil exploration failed to act on at least four warnings about vulnerabilities in subsea blowout preventers, the critical safety device that failed to shut down the Gulf oil spill when the Deepwater Horizon oil rig exploded April 20. Each of those four design flaws – detailed in three studies conducted for the US Minerals Management Service (MMS) during the past decade – threatened the ability of blowout preventers in deep water to function in an emergency. Yet the flaws did not result in federal safety alerts or tougher standards for blowout preventer (BOP) manufacturers, say experts familiar with the MMS response to such findings.”