A tourist submarine operated by OceanGate Expeditions, carrying five passengers, has gone missing during a visit to the Titanic shipwreck site in the Atlantic Ocean.

The US Coast Guard and Canadian authorities initiated a search and rescue mission on Monday, June 19, after the submarine lost contact with a Canadian research vessel on Sunday morning, June 18, about one hour and 45 minutes into its dive.

The submarine had embarked on an underwater expedition to the Titanic shipwreck, which lies approximately 12,500 feet beneath the ocean surface off the coast of Newfoundland, Canada. OceanGate Expeditions, known for offering exclusive tours to the Titanic wreck site, confirmed that the submarine belonged to their company and said their primary focus is on the safe return of the crew members.

Hamish Harding, a British businessman and explorer who gained fame for his space trip aboard Blue Origin last year, is among those on the missing submarine. His family has asked for thoughts and prayers via social media.

The submarine is reported to have only a four-day supply of oxygen left. OceanGate’s tours, which can cost up to $250,000, typically consist of dives lasting up to 10 hours as part of an eight-day trip.

The Titanic, which sank in April 1912 after hitting an iceberg, has been a popular tourist destination since the wreck was discovered in 1985. The site gained additional fame through the 1997 James Cameron film “Titanic.”

OceanGate relies on Elon Musk’s Starlink satellites for communication due to the location’s remoteness. The company had planned two more expeditions for June 2024.

Recent efforts to explore the wreck also included over 700,000 scans released by Atlantic Productions and Magellan Ltd, showcasing detailed 3D reconstructions of the ship.

The Boston Coast Guard has not provided additional information on the search.