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Although we didn’t know where all the divers got
their gear, we did know that information in 47 cases.
Of these, 36 percent were wearing rented or borrowed
equipment. The percentage was the same for freshwater
diving fatalities both inside and outside of dive parks,
but it was a much higher rate than for diving deaths in
the sea, where we found that just 26 percent of divers
who died were wearing unfamiliar gear.
Fatalities in dive parks peaked in May, earlier in
the year than those in other freshwater sites or in
the sea. I wondered if this timing might be a result of
many divers returning to diving after the winter with
a day at their local quarry. Maximum depths where
divers died were significantly deeper in dive parks
(76 feet compared with 39 feet outside of dive parks),
and technical diving was also more common in dive
parks than at other freshwater sites (17 percent versus
6 percent), probably due to greater access to deeper
depths. Training was the purpose of the dive in 28 of
the 110 freshwater deaths (25 percent).
The top three causes of death were drowning,
cardiac problems and arterial gas embolism (AGE), as
is commonly found in the sea. One thing that stood
out, though, was that all five AGE events occurred in
dive parks.
It was important to DAN researchers to figure out
how to use these data to assist the diving community,
so our next step was to look at our database of diver-
supplied reports to help us better understand the
causes of injuries and incidents. This incident report
from a dive park contains some common elements:
I accompanied a class of students on a dive in a
quarry. We visited a helicopter in water deeper than 60
feet. Once the class had performed their exercises, my
buddy led the way from the helicopter to an underwater
boat. The instructor and students followed at a
distance. When we arrived at the boat, which was at
about 45 feet, we stopped and turned around.
Unknown to us, about 10 yards away a diver in the
class began to experience difficulty breathing through
his regulator, and he quickly became low on air. He
looked at his pressure gauge and saw that the pressure
dropped to zero with each difficult breath. I did not
see him since he was coming down at an angle and
I was facing away from him. My buddy handed the
diver a spare air supply twice, and he let go of it. He
looked panicked.
Fortunately, staying calm saved the day in this case,
and both divers surfaced unharmed. However, this
incident should remind us all to regularly check our gas
supply, especially when we dive deeper than usual. This
incident also includes common elements of incidents
such as a diver in training, diving more deeply than
usual and being at risk of a panicked ascent, which is a
well-established factor in many AGE deaths.
SUMMARY
On average, 11 divers die each year in fresh water in
the U.S. and Canada. Almost half of these deaths occur
in dive parks, which are typically deeper than other
freshwater dive sites. Technical diving was more common
in dive-park deaths than in deaths outside of dive parks.
Training was the purpose of the dive in 25 percent of
the fatalities. Unfamiliar gear is a hazard for all divers;
it may be more common at freshwater sites where
training is popular. DAN recommends that divers take
a few minutes before diving to become familiar with
any new, borrowed or rented equipment. Check it
carefully before entering the water, and when possible
try it in water shallow enough to stand up in before
going deeper. In particular, familiarize yourself with
buoyancy control and emergency weight-removal
systems, which vary among manufacturers.
Given that buoyancy problems and rapid ascents
are linked to the risk of AGE, DAN recommends that
divers try to avoid blue-water ascents when possible.
In dive parks this might mean following an old quarry
road away from shore and then back again at the
end of the dive or using an ascent line and buoy for
reference. If you must surface in open water, consider
deploying a surface marker buoy connected to a reel,
locking the reel and using the line as a reference.
Based on the types of incidents most often submitted
to DAN’s online reporting system, divers should
remember to regularly check their remaining gas.
Remember DAN’s top three tips for safe diving in
fresh water: Dive with familiar gear, avoid blue-water
ascents, and keep an eye on your gas gauge.
AD