http://oceanquestcharters.com/en/.

Following is a medical description of Joe's death by Dr David
Sawatzki MD, a Diving Medicine Consultant and Mine Quest Team Member
who was also present at the dive site when the incident occured:

Joe headed out on the mainline from a depth of 50 ft, about 300 feet
from the surface. His body was found on the ceiling of the passage
at a depth of approximately 30 feet about 250 feet into the mine, an
hour or so later. His mask was full of water and the second stage of
his primary regulator was missing (it had come off the LP hose and
was found later on the floor).

The autopsy showed that Joe had died from arterial gas embolism. It
also showed that he had a mass in the periphery of his lung and
another mass in his liver, most likely cancer. It was the opinion of
the pathologist that these masses would not have caused any symptoms
and would not have shown on chest x-ray. Joe almost certainly did
not know of them.

Arterial gas embolism is virtually impossible in this section of the
mine in a diver with normal lungs. The passages are 10 feet high and
at a 10 degree slope. The average cave diver swims at 50 ft per
minute and swimming 50 ft up slope results in an ascent of 8 feet.
Joe had done three dives the week before his death in the same
passage without problem.

The mass in Joe's lung must have been mostly obstructing one of the
airways in his lung. As he descended the part of his lung supplied
by the obstructed airway would have collapsed and then slowly
inflated at depth. As he swam back up the passage, the gas would
have expanded. The obstructed airway was obviously large enough to
allow the gas to escape at the normal ascent rate of 8 feet per
minute on the first three dives.

On the day of his death, when Joe left the 50 foot depth and started
swimming up the slope to surface, the obstructed part of his lung
would have fully inflated. The second stage of the regulator he was
breathing most likely separated from the LP hose at that point,
causing Joe to hold his breath as he attempted to insert his
secondary regulator. The rest of his lungs would almost certainly
NOT be fully inflated at this time. While he was holding his breath
he must have floated to the roof of the passage, ruptured the section
of the lung beyond the obstruction and suffered arterial gas
embolism. In this situation, the embolism would have happened if Joe
simply lost control of his buoyancy and floated to the ceiling, even
if he had been breathing normally. In a diver with normal lungs,
embolism is virtually impossible at this depth in this passage.

Joe's death was from arterial gas embolism, primarily as a result of
the lesion in his lung, most likely cancer. If it was cancer and it
had already spread to his liver, he could have expected a miserable
death in a relatively short time. Dying a peaceful death, doing an
activity he loved, in the company of friends would be considered by
most people to be a far better way to die than to die from lung
cancer.