W&T said the fire started on Wednesday at 10:00am local time and was extinguished about an hour and a half later.
The company said all three personnel onboard the platform at the time the fire broke out were safely evacuated, however it added one person suffered minor injuries and was treated a local hospital and subsequently released.
It estimated less than two barrels of oil was discharged into the water as a result of the incident which created a sheen.
“At this time, the sheen appears to be quickly evaporating. The platform has been safely shut-in,” W&T said in a statement released late on Wednesday.
Based on its initial findings, W&T said it appeared the fire was caused by a leaking connection on the vertical heater treater but added a further investigation would be carried out to determine the root cause of the equipment malfunction.
It added that output from the platform would resume once all repairs and maintenance had been carried out.
The Ship Shoal 233 B platform lies in 128 feet of water, about 30 miles south of Louisiana in the Gulf of Mexico.