Emergency management officials said it appears there was an over-pressurized oil tank and its top was blown off.
Two people were burned in what officials are calling a "flash fire." The employees have been identified as Kent Moneymaker and Johnathan Taylor.
Medical helicopters took the injured to the UNC Jaycee Burn Center in Chapel Hill. They reportedly only suffered minor injuries.
At the Noble Oil, a oil recycling facility, a tank in a group of several was missing its top, which was seen lying on the ground nearby. The inside of the tank appeared to be blackened.
The cause of the accident is under investigation by OSHA.