Cubanski said the platform appeared to be structurally sound. After the April 2010 explosion on the Deepwater Horizon, that rig burned for about 36 hours before suffering structural collapse and sinking to the Gulf floor.
The Black Elk platform is in 56 feet of water. Cubanski said 28 gallons of oil were in the broken line.
The Coast Guard got the call about the fire at 8:42 a.m. CST.
A federal official in Washington said a team of environmental enforcement inspectors was flying to the scene.
David Smith, a spokesman for the Interior Department's Bureau of Safety and Environmental Enforcement, said the team was dispatched from a Gulf Coast base by helicopter soon after the Coast Guard was notified of the emergency. Smith said the team would scan for any evidence of oil spilling and investigate the cause of the explosion.
Black Elk is an independent oil and gas company headquartered in Houston, Texas.
The company's website says it holds interests in properties in Texas and Louisiana waters, including 854 wells on 155 platforms.