(Mariner Energy item updated with further information on the accident at the company's Vermillion platform.)NEW YORK ( TheStreet) -- A fire broke out on an offshore platform owned by Mariner Energy ( ME) in the Gulf of Mexico, a region still reeling from the aftereffects of the massive BP ( BP) oil-spill disaster -- but whether the accident has caused a leak remains unclear. Workers were sandblasting the platform when the fire occurred, and production had been halted, a Mariner Energy spokesman told CNBC Thursday morning. All 13 of the platform's crew were accounted for, and no injuries were reported. The spokesman also said there was neither evidence of a spill, nor any visible sheen on the surface of the water. Later in the day, Mariner issued a statement saying that after an "initial flyover, no hydrocarbon spill was reported." But the U.S. Coast Guard told the AP Thursday that it had located a slick not far from the Mariner platform. The slick measured a mile long and about 100 feet wide, according the Coast Guard. Other reports indicate that the fire is still burning as of Thursday afternoon. According to New Orleans' WDSU, the accident occurred Thursday morning, and rescue vessels from both Houston and New Orleans have responded.