I am writing this account of my own accord in hope that it is of service to the cave diving community. I have the full approval of the dive shop’s owner to write this account. A medical professional I am not; I am an artist and a cave diver. It is my intention to present the facts and to relate the incident as honestly as I am able.
Carbon Monoxide is a colorless, tasteless gas that is a product of incomplete combustion. It is 200 times more cohesive to hemoglobin then O2 which simply means Hemoglobin likes CO a lot, a lot more then it likes Oxygen. Standard treatment is with Hyperbolic O2. Chamber ride does not rid you of existing CO; the CO that is attached to the hemoglobin will remain attached to that hemoglobin. This is simply because it’s still 200 times more cohesive even in a pure oxygen environment, however, the pure O2 environment allows for O2 to attach to any uncontaminated Hemoglobin, if you have any uncontaminated Hemoglobin to attach to O2. Removing diving from the equation, carbon monoxide is a leading cause of death by poisoning in the United States at over 200 per year. Most of these deaths occur during winter months by faulty or inadequately ventilated space heating systems. (1) Cause of death is determined during an autopsy by testing the level of CO in the victim’s blood. (2,3) For dive purposes it can be from a compressor failure. The first prevention of this is to do regular maintenance on the compressor and to have the gas tested quarterly. What happens when a shop does this and still has a compressor failure. That’s what this article is about.
As most of you are aware I am a diligent promoter of all gas analyzing particularly but not limited to CO. This is because, I was a member of a mapping team in Mexico who lost a diver due to CO poisoning. This was discovered during the diver’s autopsy. Upon returning to USA, I purchased an Analox CO analyzer and have never failed to analyze every tank I dive for at least CO and O2 levels. I also purchased a Sensorcon CO analyzer as a backup. On Thanksgiving morning, this habit saved my life before a dive into Cow Springs.
That day, I analyzed my tanks to discover that my back gas contained 35 and 38 ppm and my stages contained 10 and 12 ppm. My O2 bottle which had been filled separately was 0 ppm. The strange thing that happened even though I mentally accepted that a CO hit can happen anytime without warning, I was not prepared emotionally that I could be hit twice. I had used my Analox, and then got the same readings off the Scensorcon. My first reaction was that maybe the analyzers were wrong. We then returned to Dive Outpost and barrowed a third CO analyzer and got even higher readings. My cell phone doesn’t work in Laraville so I used Dive Outpost phone and called the shop where I got the fills and got the voice mail. I left a detailed message with what was happening and the readings I got. With nothing more I could do at the moment, I rented tanks (got 0 ppm on both analyzers) and did the dive. Upon completion of the dive I tried the shop again. I got the owner told him what happened but he had already discovered the problem, had shut down his banks and stopped selling gas. At the time of the second call, he was already calling and e-mailing costumers who had recently purchased gas and telling them not to dive the tanks. In short, he had an accident and was taken safety first. He was being open and honest to all his customers.
In my research since Cozumel, the common factor with any CO or possible CO accident is that they all were reputable stations that test their gas regularly right up to the moment of the accident. That’s what happened here – an accident. While we may never know exactly what happened inside the compressor we do know the following. The compressor was maintained accorded to common practice and the gas was analyzed regularly. One such maintenance was performed on Friday November 21st 2015, and the filters were checked and no defect was found. I filled my tanks on Monday November 24th 2015, than analyzed them pre-dive November 27, 2015. Sometime between regular maintenance on Friday and my getting gas Monday evening a filter (which had been checked) burnt out and combusted creating the above incident. In short, despite being diligent and doing everything correctly, an accident happened anyway.
The shop owner, by contacting all affected costumers, helped make this accident a non fatal one. I didn’t become a statistic because I became diligent about analyzing my gas. The shop owner by being fore right prevented others from becoming a statistic. The shop owner then preformed free VIPs and O2 cleaning on all tanks and paid for this to be done by shops local to out of state customers. He was also being completely open to his costumers explaining the event and showing the effected part. His station was broken down and was re-O2 cleaned. He so far has a partial station opened and I have gassed up 3 times and all tanks have been 0 ppm and the proper O2 content. The lesson here is simple do not trust anyone to keep you safe, even if that person/shop is doing everything correctly. It’s your life and it’s worth far more than the cost of analyzers. Remember Brendan’s Law: Know what you’re breathing. Analyze your gas for O2 and CO. Analyze your gas each time, every time, anywhere. Carbon Monoxide has and will kill.
Sources
- Center for Disease Control and Prevention
https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6030a2.htm
- Center for Disease Control and Prevention https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6303a6.htm
- Wikipedia
https://en.wikipedia.org/wiki/Carbon_monoxide_poisoning
- goggled “how is CO poisoning confirmed in an autopsy” and got over twenty Newspaper accounts of coroners confirming CO poisoning Cause of death.
- RPC Engineering and Science
https://www.rpc.ca/english/pdf/BAWhyDoSamplesFail.pdf
- Trace Analytics
https://www.airchecklab.com/resources/Carbon-Dioxide.pdf
- Diving Medicine by Fred Bove MD, PhD.
https://www.scubamed.com/divmed.htm
Just FYI, treatment for CO poisoning is “HYPERBARIC” oxygen, not “HYPERBOLIC”.
https://www.dictionary.com/browse/hyperbolic
What burned the filter ?
2 things come to mind.
Somebody was not monitoring a nitox stick properly and the compressor got a blast of concentrated oxygen, or it was a brand new filter that suffered from exposure to a LOT of water, ( I have seen filter towers burn, the aluminum actually melt as a result) so a problem with a sepertor.
Pat on the back for sharing your experience, but how about we look for a root cause. this kind of thing is quire rare, and lessons learned are very valuable. Please provide us with the cause of the fire in the compressor.