Most wouldn't guess by looking at him, but Jack D. Gehringer dives much deeper than most would dare go.
A one-legged amputee, the 74-year-old Thomas Township man steers his motorized wheelchair each day into the Covenant Wound Healing Center in Saginaw, jokes with staff and readies himself for immersion into a hyperbaric chamber.
Reminiscent of the movie, "2001: A Space Odyssey," the treatment in the sleek glass chamber is called a "dive" because it simulates with air the pressure one feels submerged 66 feet below water.
"I come ready to dive," Gehringer grins.
A diabetic, Gehringer has relied on the oxygen-rich treatments to accelerate healing of a deep leg wound.
Without it, doctors say, he risks gangrene and amputation of his left leg.
Gehringer can't imagine life as a double amputee -- a life without weekly bridge games and monthly gambling runs to Soaring Eagle Casino and Resort near Mount Pleasant.
Most of the patients are diabetics who suffer poor blood circulation and need the oxygen treatment to spur healing and cell growth, but it also is used for those with bone infections and slow-healing ulcers.
They faced an amputation," says Dr. Andrew Cohen, a podiatrist at Diabetic Foot Center of Mid-Michigan, 4224 State, in Saginaw Township.
Darci Hillert, the center's program director, explains that other clothing fibers are combustible in the oxygen-rich, pressurized environment.
For the same reason, patients cannot take books or magazines to read as they lie in the glass chamber; the glue could catch fire.
His Medicare and Blue Cross/Blue Shield policies cover the $100,000 cost for the entire treatment, but Cohen says some insurers turn down the treatment because they still consider it experimental.
The Navy has used the technology for many decades to treat deep-sea divers experiencing the bends, and, within the past 10 years, an increasing number of hospitals nationwide have used hyperbaric chambers to treat patients like Gehringer with success.