An explosion tore through an oil platform in the Gulf of Mexico on Friday, triggering a fire and injuring at least 11 people, authorities said. Rescue planes and helicopters are searching for at least two crew members who are still missing. The incident happened roughly 20 miles off the coast of Grand Isle, Louisiana, on a platform used for production, not drilling. About 28 gallons of fuel spilled into the region, according to Coast Guard Response Division Chief Ed Cubanski. A half-mile oil sheen reportedly stretched near the area. The 11 injured were airlifted off the platform, and nine additional crew members were safely evacuated off the platform, according to the Coast Guard. Four of the injured were taken to West Jefferson Medical Center in Louisiana where they were listed in critical condition, a hospital spokeswoman told CNN.