Four contract workers were injured after a fire at Chevron's 356,440 barrels-per-day (bpd) Pascagoula, Mississippi refinery on Monday, the company said in an email statement. 

An incident at the refinery’s wastewater treatment area led to the fire, a Chevron spokesperson said. 

The spokesperson added that the fire was extinguished quickly and three of the injured were transported to a local hospital for further treatment.

"The cause of the incident is being investigated," the company said.