NEW ORLEANS (AP) – A University of California-Berkeley engineer who played a prominent role in investigating levee breeches in New Orleans after Hurricane Katrina is scheduled to be the first witness Tuesday at a trial involving another Gulf Coast catastrophe: the worst offshore oil spill in U.S. history.

Robert Bea, an expert witness for the plaintiffs who sued BP PLC and other companies involved in the Deepwater Horizon disaster, will share his theories about what caused BP’s Macondo well to blow out on April 20, 2010, provoking an explosion on the Horizon rig that killed 11 workers and spewed an estimated 172 millions of gallons of crude into the Gulf.