Coast Guard says 40-41 hours of 'breathable air' left on missing sub

The Coast Guard estimated Tuesday that there are 40 to 41 hours of oxygen left onboard OceanGate's missing Titan sub, which vanished during a dive to the Titanic wreck site. 

Capt. Jamie Fredrick, U.S. Coast Guard First District response coordinator, told reporters in Boston that an ongoing search with the assistance of the Canadian Coast Guard in an area "larger than the state of Connecticut" has not yet turned up any signs of Titan. 

"There's about 40 hours of breathable air left based on that initial report" of the Titan’s disappearance Sunday morning, he said around 1 p.m. local time. 

That would mean the ship would run out of breathable air on Thursday morning.

LIVE UPDATES: SEARCH FOR MISSING OCEANGATE TITAN SUBMARINE

Fredrick said as soon as the Coast Guard received a report Sunday evening of the Titan’s disappearance, "we immediately launched search efforts."

"We flew assets that evening and we've continued constant surface and air assets searches since that point," he added. 

He also said, "Our thoughts and prayers are with the crew and the families and their loved ones." 

Just prior to the press conference, an OceanGate spokesperson told Fox News that the company's CEO, Stockton Rush, is among the five people who are now missing. 

"OceanGate can confirm that CEO Stockton Rush is aboard the submersible as a member of the crew," the spokesperson said. 

IMAGES SHOW OCEANGATE TITAN SUBMARINE'S FINAL MOMENT BEFORE IT BEGAN DIVE TO TITANIC 

One of Pakistan's richest men, Shahzada Dawood, his son Sulaiman Dawood, and the United Kingdom's Hamish Harding also have been confirmed as being on board the missing Titan. 

Fredrick said "search efforts have focused on both surface with C-130 aircraft searching by site and with radar and subsurface with P-3 aircraft."

"We're able to drop in monitor sonar buoys today," he told reporters. "Those search efforts have not yielded any results. Search efforts have continued through last night and today." 

New images also have emerged showing what appear to be the OceanGate Titan sub’s final moments on the surface of the Atlantic Ocean before it disappeared underwater. 

The photos taken Sunday were posted on Instagram by Action Aviation, whose chairman Hamish Harding is among the five people missing onboard the vessel.

Images appear to show Titan floating on a platform just prior to it being launched into the water. 

Fox News’ Tamara Gitt contributed to this report.