Race Against Time: Search for Missing Titanic Submersible Intensifies as Oxygen Runs Low.

The search for the missing submersible on an expedition to view the wreckage of the Titanic neared the critical 96-hour mark Thursday when breathable air is expected to run out, reaching a vital moment in the intense effort to save the five people aboard. The Titan submersible was estimated to have about a four-day supply of breathable air when it launched Sunday morning in the North Atlantic. Rescuers have rushed more ships and vessels to the site of the disappearance, hoping underwater sounds they detected for a second straight day might help narrow their search in the urgent, international mission.