At about 5:30 PM, as the abandonment of Lexington was nearing completion, a large explosion tore through her hangar amidships.

Fires were now “roasting” torpedo warheads stowed in the after hangar, and these detonated in a spectacular blast soon after the carrier’s Commanding Officer, Captain Frederick C. Sherman, left her. In keeping with the rules of the sea, he was the last man off. Thereafter, the great carrier burned furiously, shrouded in smoke almost from stem to stern. She was finally scuttled by destroyer torpedoes and sank at about 8 PM.

After slipping beneath the waves, the carrier would not been seen again until March 2018 when the wreck was located by Paul Allen’s team.

Sources:
history.navy.mil
U.S. Naval Institute