New Orleans, La. – Coast Guard Rear Admiral Mary Landry says hope is fading that the 11 workers could be rescued alive. The platform exploded Tuesday night and sank 36 hours later. Relatives say they're bracing for the worst. Meantime, environmental groups are warning there could be disastrous consequences from oil leaking at the site. Spokesmen for platform operator Transocean of Houston and BP, which contracted the drilling rig, say they aren't sure where oil seen on water above the wreckage is coming from. Underwater robots are checking the sunken rig. Some fear as much as 336,000 gallons of crude could be seeping into the Gulf.