[7] Exley died at age 45 while trying to set a depth record by diving the world's deepest sinkhole, Mexico's 1,080-foot (330 m) deep, Zacatón, a fresh water cenote.
[8] In the book, Diving into Darkness (a story about Dave Shaw and Don Shirley), the author comments: "Exley's status in the sport is almost impossible to overstate".
To finance this passion, Exley worked as a mathematics teacher at Suwannee High School in Live Oak, Florida.
[11] Exley and German cave diver Jochen Hasenmayer became friends and rivals in the 1980s, each repeatedly attempting to break the depth records of the other.
[15][16] Exley died, aged 45, on April 6, 1994, while attempting to descend to a depth of over 1,000 feet (300 m) in a freshwater cenote, or sinkhole, called Zacatón in the state of Tamaulipas, Mexico.
[9] The remipede L. exleyi, discovered by Australian cave divers Andrew Poole and Dave Warren in August 1993, was named in honor of Sheck Exley.