Article: Carbon Monoxide in Scuba Tanks: Risks and Protection

[Johnmpcny]

It's a new option that developed after I wrote the article. See my current Sig for a link, or his...

In the mid 70's when I started "bad air" was taught as risk to be considered. NASDS of course said use only a NASDS shop to do your fill. In real life if a diver got a bad tank the word spread and said shop was black balled by divers. I am not at all sure how real it was but you would hear go here not there as the guy had done bad air fills. Some of these rumors I bet were started by the competition.

That said I asked when I did a re-cert 2 years ago while this is not talked about, the DI said it is a non issue today and PADI does not make mention of it.

 

[DandyDon]

In the mid 70's when I started "bad air" was taught as risk to be considered. NASDS of course said use only a NASDS shop to do your fill. In real life if a diver got a bad tank the word spread and said shop was black balled by divers. I am not at all sure how real it was but you would hear go here not there as the guy had done bad air fills. Some of these rumors I bet were started by the competition.

That said I asked when I did a re-cert 2 years ago while this is not talked about, the DI said it is a non issue today and PADI does not make mention of it.

We didn't even have home smoke alarms in the 70s, did we? Sad that some homes today still don't, or lack a $1 battery. Home CO alarms start at less than $20, but many homes and I think most businesses lack those. It snowed in the northeast recently, and this broke about that time: Gazette.Net: Five killed in Oxon Hill carbon monoxide leak identified

My daughter's school only has one CO monitor - the one I gave her for her classroom, and I got them one for each bedroom even tho they have an all-electric home - aside from the garage near my grandkids and the fireplace on the other side of the house. I take one for each hotel room on trips, and they just smile. I doubt they take one on trips I don't join, as much as I ask, but they didn't grow up heating with space heaters before sensor technology. I keep nagging gently and hope...

Tank testing technology is so much more precise, but now affordable. The more divers test, the more providers will try to prevent problems, and hopefully close calls will be very rare - losses more so. It's worth the effort and expense to know for sure, I think - and I think all the divers on the boat where we found 17 ppm agree now.

I saw a recent post on another board where one diver in a group had a CO tester, used it even tho the others didn't seem to care, and found 10 ppm. They drained and vized, finding significant oil deposits. 10 ppm isn't all that much, but if that gets thru - what else...??

 

[colincross]

Let me Start off by saying this is the first forum i have ever entered, Secondly I would Like everyone no here who I am, I am the Husband Of the recently Deceased woman Killed In Cabo San Lucas On March 3rd of this year. This incident was, I have to say at this point in time (allegedly) by Carbon Monoxide in her tank. We have just had a ceremony here in the Bahamas for her. While i was here, i put my new CO detector to use, I tested over 30 tanks i detected ranges from 1-6 ppm. Wikipedia states that death will occur at 3,600 ppm within 30min. So my question is, does anyone know the formula or calculations for relative surface tests to each level of depth? My wife was only in the water for a total of 10min 26sec. My CO tester has an alarm for 10ppm, but that must translate into a much higher level at depth.

On a second note, I have to agree, that CO testers should be enforced at all dive shops. the reason, well i had a conversation with a dive shop owner and his answer was "I am away from the elements, and i use an electric compressor". well here is my answer to that, CO levels do not have to be introduced once to affect a diver, but repetitive refills some times with low levels building up can result to a fatal dive, so if a fill station is filling someone else's tank and thy use other locations to fill as well, Than TEST THE TANK!! to me it just makes sense! seems we pay more attention to our air censor in our car than the air that we count on for life!

Thanks for any help provided.

 

[DandyDon]

Hi Colin. I am very sorry for your loss. Your wife's accident was discussed with a lot of speculation, debate, and unanswered questions on a thread in our Accidents forum. See http://www.scubaboard.com/forums/accidents-incidents/413185-fatality-cabo-san-lucas-march-3-a.html

I am really not the expert to answer some questions, but yes - CO toxicity increases with partial pressure at depth, but there is a lot more to it than that....

• As the diver ascends, the partial pressure of Oxygen that was offsetting the CO in part decreases rapidly, while that of CO very slowly.
• Additionally, if CO is allowed to enter the tank - one has to wonder what other contaminants might be in it as well.
• And more - not all of it well understood, hence the low amounts legally allowed in countries that do regulate.

I really do not think that CO leaves a residue in a tank from repeated exposure, but an electric compressor can still produce toxic tank fills from other fumes that might be intaken and/or by partially burning its own lubricating oil as the machine heats up. You never know about the next tank without testing. I do hope you can obtain some dependable answers on your wife's tank tests at least.

I think these limits for CO exposure at one atmosphere are more dependable than those given by Wiki: Risks of Carbon Monoxide poisoning

 

[ktomlinson]

Excellent article DandyDon! I own an Analox CO tester thanks to your drive to get the word out!

 

[DandyDon]

Excellent article DandyDon! I own an Analox CO tester thanks to your drive to get the word out!

Hope you will report any positive readings from your travels. Always getting zeros is boring I know, but so reassuring.

 

[Tao of the Dive]

I prefer for my pre-dive testings to stay boring, as the alternative is more excitement than I prefer.