A technician responsible for monitoring gas levels has told federal investigators he never considered using his authority to stop work on the doomed Gulf of Mexico oil rig even though mud-moving activities in the hours before the blast made him uncomfortable.

Joseph Keith, who works for a unit of Halliburton, told the joint U.S. Coast Guard-Bureau of Ocean Energy Management, Regulation and Enforcement panel Tuesday that the BP wellsite leader and mud engineers onboard would have been in a better position to assess whether work should have stopped.

An explosion aboard the Deepwater Horizon on April 20 killed 11 men and led to more than 200 million gallons of oil spewing from BP’s undersea well.

The panel is nearing the final stretch in its quest to assign blame for the disaster.