The device meant to stop oil leaking from a Gulf of Mexico well after last month’s rig explosion was faulty, US Congressional investigators have said.
The blowout preventer (BOP), a set of huge valves, had a hydraulic leak and a failed battery, they said after studying documents from BP and others.
Oil industry chiefs say it is too early to conclude what caused the disaster.
A climate change bill just submitted to the Senate could allow states to veto some offshore drilling plans.
Meanwhile, President Barack Obama has also proposed new legislation which foresees $188m (