When divers are asked what their most important piece of gear is, many people mention masks, computers and regulators. However, they are overlooking the most important piece of gear you use: breathing gas.
Without a cylinder of air – normal or enriched – we would not be able to SCUBA dive, only free diving would be possible.
New divers are trained during their certification courses to always test their air while setting up their equipment, both to make sure they have enough and that it doesn’t have any strange smells. Some instructors we’ve seen even suggest air from a tank should smell similar to “the inside of a basketball”.
Beyond just doing a “sniff test”, divers who use any form of enriched air are familiar with the use of air analyzers to check to ensure the mix they are using is the same as what they’ve used to plan their dives.
Unfortunately, a diver died recently while on a cave dive, but not due to any of the typical inherent dangers of cave diving. Instead, the cause of death has been determined to be carbon monoxide poisoning.
Carbon monoxide, also known as the “silent killer,” is an odorless, tasteless gas. However, even in small amounts, inhalation can be life threatening. Compound those dangers with the pressures from diving, and carbon monoxide can become even more dangerous.
While some US states require carbon monoxide detectors in homes by law, portable carbon monoxide detectors for divers haven’t been a regular piece of dive gear kits for people. While the Diving Equipment and Marketing Association (DEMA) trade show is just over a week away and several vendors are promising a variety of diver carbon monoxide detectors, as of this time, LeisurePro carries the Analox Carbon Monoxide Analyzer. While it is not an inexpensive dive accessory, it can be one of the most valuable.
Normal breathing air should have a maximum of 10 parts per million (ppm) of carbon monoxide. Based on a chart posted on CaveDiver.net, these are the signs and symptoms of carbon monoxide poisoning:
35 ppm (0.0035%) – Headache and dizziness within six to eight hours of constant exposure
100 ppm (0.01%) – Slight headache in two to three hours
200 ppm (0.02%) – Slight headache within two to three hours; loss of judgment
400 ppm (0.04%) – Frontal headache within one to two hours
800 ppm (0.08%) – Dizziness, nausea, and convulsions within 45 min; insensible within 2 hours
1,600 ppm (0.16%) – Headache, tachycardia, dizziness, and nausea within 20 min; death in less than 2 hours
3,200 ppm (0.32%) – Headache, dizziness and nausea in five to ten minutes. Death within 30 minutes.
6,400 ppm (0.64%) – Headache and dizziness in one to two minutes. Convulsions, respiratory arrest, and death in less than 20 minutes.
12,800 ppm (1.28%) – Unconsciousness after 2-3 breaths. Death in less than three minutes.
As the chart shows, carbon monoxide poisoning is very serious. If you are diving in remote or locations where you are not personally familiar with the tank fill operation, it would be a prudent choice to add a carbon monoxide analyzer to your SCUBA gear kit or perhaps share one amongst a dive group.
Our condolences go out to the family who lost a loved one from this tragic, unnecessary accident.
