[Editor's note: This story was updated from a previous version posted at 2:35 p.m. CST Jan. 22.]

The bodies of five people killed in an Oklahoma oil well explosion were recovered in the afternoon on Jan. 23 in a building adjacent to the drilling site outside of Quinton, Okla., Pittsburg County Sheriff Chris Morris said at a briefing.

The bodies were transferred to the medical examiner in Oklahoma City, he said. The five had been missing and presumed dead since a fiery explosion ripped through the site a day earlier.

The accident on Jan. 22 occurred at a Red Mountain Energy Inc. well that was being drilled by contractor Patterson-UTI Energy Inc. (NASDAQ: PTEN). Red Mountain Energy is a privately-held oil and gas exploration company based in Oklahoma City.

Its officials did not respond to requests for further comment.

The men were identified as Josh Ray, 35, from Fort Worth, Texas; Cody Risk, 26, of Wellington, Colo.; Parker Waldridge, 60, of Crescent, Okla.; Roger Cunningham, 55, of Seminole, Okla.; and Matt Smith, 29, of McAlester, Okla.

Three of Patterson-UTI's employees were among the victims. Officials have not said who employed the other two.

The U.S. Occupational Safety and Health Administration, U.S. Chemical Safety Board and the Oklahoma Corporation Commission are investigating the accident, Morris said.

The fire on Jan. 22 had been fed by gas from a well being drilled for Red Mountain Energy, preventing a full search of the scene throughout the day, but was later extinguished, the Pittsburg County Emergency Management Department (PCEMD) said in a statement.

Houston-based Patterson-UTI said in a statement late on Jan. 22 the cause of the well explosion remained unclear.

"Well control experts and emergency responders are on site and we will conduct a thorough investigation when the incident is fully contained," Patterson-UTI CEO Andy Hendricks said in a statement.

PCEMD director Kevin Enloe said one of the 22 workers at the site when the explosion occurred was treated for injuries and 16 others were uninjured.

The blast occurred at around 9 a.m. CST (15 GMT) near Quinton, Okla., about 146 miles (235 km) from Oklahoma City.

Boots & Coots Inc., Halliburton Co.’s (NYSE: HAL) well control and prevention service, was called in to put out the fire. Staff from the state's energy regulator, Oklahoma Corporation Commission, were also on the scene, officials said.

The explosion is the latest in a series of accidents at oil and gas fields in the state. A gas explosion occurred at a Trinity Resources Inc. well in the same area in February 2017, injuring a worker.

More recently, a 40-year-old Oklahoma man was killed in a backhoe accident this month at an oil field near Ninnekah. Another worker was killed last month when equipment collapsed at a site near Preston, and a 36-year-old man was killed in November when a fitting failed during fracking at a well near Watonga, according to media reports.

Accidents during oil and gas drilling claim about 100 lives a year in the United States, according to the U.S. Centers for Disease Control (CDC). Using data from the Bureau of Labor Statistics, the CDC reported 1,189 workers were killed in the 11 years ended 2013, a period of intensive drilling.

Two-thirds of the fatalities involved transportation or contact with objects or equipment, the CDC found. More than 50% involved employees of oilfield service companies.