One person was killed and another was injured after an oil refinery detonation rocked the town of Wynnewood late Friday.
Wynnewood is about an hour drive south of Oklahoma City.
The medical examiner was investigating the scene Friday. Emergency response officials had been at the refinery in force for nearly four hours after residents heard a blast just before 6:30 p.m. at the Wynnewood Refinery, which is owned by CVR Energy. Residents say the blast felt like an earthquake.
"I was scared ... because everything was moving," Wynnewood resident Juan Mena said.
Mena lives not too far from the refinery.
"The detonation or the blast occurred, as I understand, from a build up of gases at a unit, Garvin County Sheriff Larry Rhodes said.
The blast occurred during what's called "turnaround time." That's when maintenance is performed on the facility. It happens once every four years. Three deputies were already at the refinery for the turnaround period when the blast went off. Rhodes says after things went wrong, it did not take long for more help to arrive.
"Police just started [arriving from] all over the place," Mena said. "They were blocking all the roads and everything."
Rhodes says family members have been notified of their loved one's death. Officials were not releasing the identity as of late Friday. OSHA is expected to be at the scene Saturday morning to begin its investigation.
Officials say the Wynnewood refinery should remain open during the investigation.
This isn't the first incident at the Wynnewood refinery.
An explosion rocked the refinery in December of 2010. In April of 2008, a fire broke out as crews were working on a pipe. Two months before, a furnace caught fire.
In 2007, a lighting strike ignited more than 20,000 barrels of oil sending flames more than 60 feet into the air. And in 2006, there was an acid leak and fire.
No one was injured in any of those incidents.