WYNNEWOOD, Okla. (KTEN) — Two workers were injured Tuesday morning when fire broke out at the Wynnewood Refining Company.

"A fire occurred at the gasoline hydrotreater at the Wynnewood Refinery. Two employees were injured and were transported off-site for evaluations," said Garvin County Emergency Management director David Johnson. "All other employees have been accounted for."

The nature and extent of their injuries was not disclosed.

The fire in a gasoline hydrotreater was reported at around 8:20 a.m. Roads near the facility in the 900 block of South Powell Avenue were closed to traffic for several hours, but had reopened by noon.

"Everything is secure," said Garvin County Emergency Management director David Johnson. "There is no threat to the community, and there are no issues outside of the refinery.

Main roads were closed for several hours while emergency crews were at the scene. 

"The roadways were shut down as a precaution to keep everybody safe," Johnson explained. "The refinery's warning system is audible. You can hear it outside the refinery, but they were only warning employees to take action, not citizens."

An employee at a nearby convenience store told KTEN she heard a loud "boom" before seeing smoke fill the air. 

"You could see all of the smoke when you walked around the side of the house," said Drew Parks, who lives nearby the Wynnewood Refinery. "You could tell it wasn't natural. It wasn't the excess from whatever they burn off. It was a lot more, and it wasn't in the right spot."

Company officials said they would conduct a thorough investigation into what caused the incident.