NEW ORLEANS (AP) — A worker who survived the deadly explosion on the Deepwater Horizon testified Wednesday that a flurry of activity on the drilling rig hindered his ability to monitor BP’s well for signs of trouble before the April 2010 blowout.

Joseph Keith, the second blast survivor to testify in person at a federal trial over the disaster, said he never saw any indications that a blowout was brewing before drilling mud started raining down on the rig floor just before the explosion. The blowout triggered an explosion that killed 11 men and led to the nation’s worst offshore oil spill.