Three days after an explosion ripped through a Patterson-UTI Energy Inc. drilling rig in Oklahoma killing five men, an investigation is underway to determine what caused the blast.

Emergency management officials were preparing on Tuesday to hand the investigation to the Occupational Safety and Health Administration. The Oklahoma Corporation Commission and other federal and state agencies are expected to assist.

Authorities were dispatched to the Patterson-UTI rig west of Quinton early Monday when the men went missing following a rig explosion. Patterson was working for Oklahoma City-based Red Mountain Energy LLC and was drilling the vertical leg of a horizontal well permitted for the Mississippian Lime and Hunton formations, as well as the Woodford Shale.

Five men were killed and 17 people were safely evacuated. The men who died were thought to be working on or near the rig floor at the time of the blast, authorities have said. The site was considered stable and safe enough for regulators to begin their work.

The survivors described hearing a “loud boom, they saw fire and they ran,” Pittsburg County Sheriff Chris Morris said. “Everyone was just trying to survive.” One man, presumably the derrickman, who was working on the mast platform high above the rig floor at the time of the incident, had enough time to realize what was happening, and was able to use the escape, or “geronimo line,” to get to the ground and off site, Morris said. He was among the survivors.

In an ironic turn on Tuesday, the Oklahoma Supreme Court ruled that oil and natural gas industry employees and their representatives may file a lawsuit following a death or injury on the job. In a unanimous opinion, the high court affirmed a lower court’s ruling and found that a workers compensation law passed in 2013 exempting oil and gas well operators from lawsuits was a special one crafted to favor the industry unlike others in the state.

The decision stemmed from a lawsuit filed by the family of David Chambers Sr., who died in 2014 from burns he suffered in an accident at a Stephens Production Co. site. Justices sent the case back to the lower court for further proceedings.

U.S. Rep. Markwayne Mullin (R-OK) also joined local authorities for the Tuesday press conference. Mullin sits on the House Energy and Commerce Committee, which he said will take a closer look at the incident.

“We never want to take something like this and not take a deep dive into it so we can debrief at the end of the day and say ”what was preventable and how can we do it better,’” he said. “That’s the goal here, that’s why the federal agencies are coming in and working with the state. We have a lot of drilling going on in our state, and if there’s something that was preventable, let’s make sure we highlight it, and it doesn’t happen again.”