One worker was killed in a boiler explosion on Friday at CVR Energy Inc.'s 70,000 barrel per day (bpd) Wynnewood, Oklahoma, refinery, a company spokeswoman said in a statement.
Another refinery employee was taken to an Oklahoma City hospital, according to Garvin County Sheriff Larry Rhodes.
There was no fire following the blast, which occurred at about 6:20 p.m. local time (1120 GMT) because the refinery was shut down for a 40-day overhaul, Rhodes said.
"There was no threat to Wynnewood or the surrounding communities," Rhodes said.
Neither the company nor Rhodes gave details about the injuries employees sustained in the blast.
Boilers are required at a refinery to generate steam for electrical power production, and for use in the crude oil refining process.
"All other employees are accounted for at this time," said CVR spokeswoman Angie Dasbach. "Company officials are assessing the situation and will provide updates as information becomes available."
CVR acquired the Wynnewood refinery when it purchased Gary-Williams Energy Corp for $525 million in December.
Wynnewood is located 67 miles south of the state capital of Oklahoma City.