Investigators say a Florida man and his 15-year-old son ran out of oxygen and died while diving on Christmas Day.
The bodies of 35-year-old Darrin Spivey and Dillon Sanchez were found hours after they went diving at the Eagle Nest Sink cave in Hernando County.
A sheriff's office investigation found the pair died accidentally after diving to 233 feet and using air alone in their tanks.
The Tampa Tribune reports rescue diver Eric Deister says the men should have used a trimix combination for their breathing instead of just air. And he says they shouldn't have gone deeper than 218 feet due to possible toxic effects.
Investigators say Spivey and Sanchez were not certified divers. They believe the pair lost track of time.