An off-shore oil rig exploded and caught fire in the Gulf of Mexico Thursday, the Coast Guard said. All 13 rig workers had been accounted for, but most had been thrown into the water, and rescue vehicles were on the way, dpa quoted Coast Guard spokesman Bill Colclough as telling CNN. The cause was unknown of the explosion on the Mariner-Energy-owned rig about 145 kilometres south of Vermillion Bay on Louisiana's coast. It was unclear whether oil was spilling into the water, but the rig was not currently producing oil, Colclough said. A rig explosion in the Gulf in April killed 11 people and unleased an oil gusher that polluted the waters for months in the worst-ever ecological disaster in the US.