The US Chemical Safety Board will investigate the blowout that killed three workers at a Chesapeake Energy well in central Texas. Regulators say the blowout that killed five workers on a Patterson-UTI rig in Oklahoma was the product of a slow-moving series of missed signals, misleading testing, and miscalculations that failed to control a natural gas influx. A new tool enables variable bore rams and shear rams to be tested in one run, cutting rig time significantly. Developing a well-specific subsea-capping contingency plan involves assessing the feasibility of deploying a capping stack from a floating vessel, determining the weight and stability, and performing dynamic-flow simulations of closing the capping stack outlets. Despite multitier safeguards, blowouts occur.