OKLAHOMA CITY - The drilling company working on a well when it exploded earlier this week had past federal workplace safety violations in the state, according to government records.
Federal authorities are investigating what caused a drilling rig to explode Monday morning. Five workers died -- three employed by drilling company Patterson-UTI Energy -- 17 others were able to evacuate the well site; one worker was flown to a Tulsa hospital for burn injuries.
The well head burned around the Patterson Rig No. 219 for hours Monday, until the well head could be shut off. Officials said the remote switch for a safety valve for the well -- a blowout preventer -- was inoperable from the explosion.
Initially, authorities listed the five workers killed as "unaccounted for." On Tuesday, authorities identified the missing men. Several hours later their bodies were found in the drilling rig's doghouse -- a multi-use room on drilling rigs and platforms.
"If that was where they were last seen and where they were working, there was a good chance they weren't going to survive," said Pittsburg County Sheriff Chris Morris during a press conference Tuesday afternoon.
Morris said the state medical examiner's office has requested dental and medical records to help identify the remains.
The federal Occupational Safety and Health Administration (OSHA) and other agencies are now looking at what led to a reported "uncontrolled gas release" from the well, according to an incident investigation report by the Oklahoma Corporation Commission.
"The safety of our employees, and everyone at the well site is always the primary concern of ourselves, our management team, our employees, our company," said Patterson-UTI President and CEO Andy Hendricks Tuesday.
The Houston-based drilling company operates 52 drilling rigs across the state -- not including Rig No. 219 -- according to the company's website.
Since 2010, OSHA conducted eleven inspections on Patterson in the state of Oklahoma, according to online OSHA records, and found four violations, the latest in June 2014. All four are closed cases and none indicated that fatalities occurred.
Three violations were related to communication or labeling of hazards on the job site. The fourth violation, from 2010, was for failure to "furnish a place of employment which is free from recognized hazards that are causing or are likely to cause death or serious physical harm to employees."
"We've operated across North America for a long time," said Hendricks, when asked about past violations at the press conference Tuesday. "There have been cases in the past. But I think the record shows that -- at least in the industry and with our customers -- we've certainly been one of the safest companies in the industry."
Federal statistics from the Bureau of Labor Statistics show seven people have died in oil and gas industry incidents in the state between 2011 and 2016.
The Quinton drilling rig explosion is one of the single deadliest events in the industry in years.
"We have a lot of drilling going on in the state," said Congressman Markwayne Mullin Tuesday, who serves on the House Energy and Commerce Committee, "and if there's something that's preventable, let's highlight it and make sure it doesn't happen again."