Two individuals working on an exploration well off the coast of Nigeria were unaccounted for following a fire that took place on a Chevron rig.

According to an announcement made Monday night, the stricken rig was drilling a natural gas exploration well six miles off the country's coast in approximately 40 feet of water.

Images of the rig show it almost completely immersed in flames.

More than 150 people were evacuated from the rig and an adjacent barge, but two contractors are still unaccounted for. The others are considered safe and are undergoing medical examinations, said Chevron.

Every effort is being made to find the missing workers, said Andrew Fawthrop, the managing director of Chevron's Nigeria and Mid-Africa Strategic Business Unit. They are our utmost priority.

The San Fransisco Chronicle reported Tuesday morning, the company suspended the operations of one of its producing wells in the area due to its proximity to the fire.

The cause of the fire is under investigation.