OKLAHOMA CITY (AP) -- An oil refinery employee remained in critical condition Sunday at an Oklahoma City hospital as work resumed at the facility where an explosion earlier in the weekend left him injured and another worker dead.
Friday's blast at a boiler inside the refinery south of Oklahoma City injured Russell Mann of Davis and killed Billy Smith, 34, of Pauls Valley, said Garvin County Sheriff Larry Rhodes. The sheriff did not know Smith's age and the hospital wouldn't confirm it.
The CEO of CVR Energy Inc., which owns the refinery in Wynnewood, said in a statement Sunday that the Sugar Land, Texas, company is working with the federal Occupational Safety and Health Administration and state agencies that are trying to determine what caused the explosion.
"I would like to express my deepest sympathy for the employees and families affected by this tragedy," Jack Lipinski said. "We are conducting a thorough investigation of the incident and cooperating fully with OSHA and the Oklahoma Department of Labor."
Rhodes said OSHA investigators arrived at the site on Saturday.
OSHA officials did not immediately return phone messages and emails Sunday.
Damage at the refinery was limited to the boiler, and no other areas of the facility were affected, according to the company's statement.
Rhodes said the explosion occurred after the plant had been shut down earlier in the week for planned maintenance, a 40-day process called a turnaround.
"There is no crude oil refining going on right now," he said.
The turnaround, a periodic shutdown of operations, is for maintenance and upkeep of operating units and resumed Saturday, the company said.
"We want to thank Wynnewood and Garvin County emergency response teams for their rapid response and assistance," said Wayne Leiker, vice president and refinery manager.
The company also had a team of firefighters on site that had the situation under control when deputies arrived, Rhodes said.
"I do know there was no fire; it was more of a blast of the gasses and the pressures that built up within that (boiler)," the sheriff said.
Highways near the site, which is 65 miles south of Oklahoma City, were shut down for nearly two hours after the explosion, according to the Oklahoma Highway Patrol.
CVR's website says the company acquired the refinery when it purchased Gary-Williams Energy Corporation in 2011. The refinery has a daily capacity of 70,000 barrels of crude and produces gasoline, diesel fuel, military jet fuel, solvents and asphalt.