Rainbow sheen in the Gulf of Mexico oil rig fire.

An oil rig fire in the Gulf of Mexico early Friday morning has caused "rainbow sheen" more than a mile long, according to the U.S. Coast Guard.

The Coast Guard said it received a report at 2:50 a.m. from an offshore supply vessel that reported a fire on board an oil production platform.

The ship evacuated the crew of 28 workers on board who were taken ashore. No one was hurt in the incident.

The oil well was "shut in and production has ceased," the Coast Guard said, which noted that the platform had an estimated 4,000 barrels of crude oil on board in storage tanks.

But David Margulies, a spokesman for Texas Petroleum Investment Co, which owns the rig, told The Times-Picayune there were actually only 100 barrels — about 5,040 gallons — on board the platform.

"The production platform where the fire occurred gathers oil and then pumps it through a pipeline so there is little oil stored on site and all wells feeding the platform have been shut down," he said.

The Coast Guard says it is investigating the incident and has response crews on scene and more on the way.