Testimony is to continue in the trial of a supervisor accused of ignoring danger signs hours before the Deepwater Horizon rig exploded in April 2010, eventually spewing more than 100 million gallons of oil into the Gulf of Mexico.

Robert Kaluza was day supervisor on the rig for energy giant BP PLC. Likely prosecution witnesses include night supervisor Donald Vidrine, who pleaded guilty to the misdemeanor charge on which Kaluza is being tried: violating the Clean Water Act.

Prosecutor Jennifer Saulino said in an opening statement Tuesday that there were several reasons the well blew, but Kaluza was partly responsible.

Defense attorney Shaun Clarke said Kaluza stopped work on the well before his shift ended and was off duty, leaving the decision of what happened next to Vidrine.