Rescuers make last desperate push as final hours of oxygen on missing Titanic submersible tick down

The race against time to find a submersible that disappeared on its way to the Titanic wreckage site entered a new phase of desperation on Thursday morning as the final hours of oxygen possibly left on board the tiny vessel ticked off the clock. The area of the North Atlantic where the Titan vanished Sunday is also prone to fog and stormy conditions, making it an extremely challenging environment to conduct a search-and-rescue mission.