Search for lost Titanic submersible expands as oxygen levels drop.

The search area for the lost submersible, Titan, on its way to the Titanic wreckage site has doubled in size as rescuers rush more ships and vessels to the area. The search is becoming increasingly urgent as the passengers' oxygen supply is dwindling, and the area is prone to fog and stormy conditions. Camera-equipped remote-operated robots are being used to scan the seafloor, and a special naval salvage system capable of hoisting large, bulky, and heavy undersea objects has arrived in St. John's, Canada. The search has drawn international attention, and newly uncovered allegations suggest there had been significant warnings made about vessel safety during the submersible's development.