The U.S. Chemical Safety Board (CSB) has published a new report on the cause of the Deepwater Horizon rig oil spill in 2010, which killed 11 people and seriously injured 17 others.

The CSB published new evidence in a two-volume report, stating that the blowout preventer (BOP) at the Macondo well, operated by BP, failed to serve its purpose and prevent the incident. The report said that the chain of events leading to the deadly explosion started in the evening of April 20, when there was a burst of pressure from the reservoir. The high pressure caused a drill pipe that went from the rig down into the ocean floor to buckle and bend, thus making it impossible for the BOP to cut the pipe and seal the well. The failure of the safety device was a direct contributing factor to the incident, the CSB said.

The report poses broader safety questions for the entire oil and gas industry. The pressure that built up prior to the incident and caused the drill pipe to curve is a threat that has not been examined in detail so far. If that happens in future, other rigs might be at risk of explosion as faulty BOP devices may remain undetected.

The regulator concluded that federal rules regarding the oversight of offshore safety, including those introduced after the Deepwater Horizon oil spill, fail to address a number of safety devices. The CSB recommends that regulation should be updated to ensure better prevention and protection.