Unknown Tourist dead, Dive Master ill - Ambergris Caye, Belize

[rlh739]

I've followed this thread carefully and have read all 23 pages. Good information in here, and as a result, I got a Forensics Detectors CO monitor for an upcoming trip to Indonesia.

At this point, is there an agreed upon level of CO that would cause one to reject a tank? I believe there were some opinions early, but is 5PPM acceptable? 1PPM? Absolutely none at all?

It would've been interesting to have one of these monitors back in the day when I was stuck in summer traffic in the Lincoln Tunnel, NYC. No wonder I was b*tchy.

Thanks!

 

[DandyDon]

At this point, is there an agreed upon level of CO that would cause one to reject a tank?

Some countries have legal limits allowed ranging from 5ppm to 15ppm. Insisting on zero would be too much as the accuracy of measurements in one-millionth increments is tricky.

 

[Rob9876]

One of the things is to keep putting their name, Ambergis Divers, in the text. Such that when someone searches for Ambergis Divers they would get this thread that has frequently t mentions of Ambergis Divers.

I do agree that this type of incident, and the invesitgation that follows, may be of legitimate interest to folks considering a dive trip with Ambergris Divers.

 

[Pearlman]

At this point, is there an agreed upon level of CO that would cause one to reject a tank? I believe there were some opinions early, but is 5PPM acceptable? 1PPM? Absolutely none at all?

I had intended to ask this question and validate my estimates a long time back but forgot about it.
Based on the table below ( factor in partial pressure of CO at 4ATM for 1hr for recreational divers ) I arrived at a quick guesstimate that anything more than 10ppm would be risky. Consider also that it’s the very first dive of a 10 day vacation that cost you $$$$ and you don’t want to retire to bed with a headache and unsure about diving the next day…

I request the more experienced and technically minded folks here to validate my assumptions…
(Edit : I think I may have mixed up ppm with percent of gas in the mix, leading to incorrect guesstimates…)

 

[LFMarm]

 

[TrimixToo]

I had intended to ask this question and validate my estimates a long time back but forgot about it.
Based on the table below ( factor in partial pressure of CO at 4ATM for 1hr for recreational divers ) I arrived at a quick guesstimate that anything more than 10ppm would be risky. Consider also that it’s the very first dive of a 10 day vacation that cost you $$$$ and you don’t want to retire to bed with a headache and unsure about diving the next day…

View attachment 856283

I request the more experienced and technically minded folks here to validate my assumptions…
(Edit : I think I may have mixed up ppm with percent of gas in the mix, leading to incorrect guesstimates…)

I won't vouch for your numbers, but in my opinion you are thinking about it the right way. With a good filter stack, the catalyst (Hopcalite or similar) should remove nearly all CO, turning it into CO2. CO2 has its own problems but they're not as bad as CO's problems. Nearly all my diving is done with air from my own compressor. The tests come back with "ND" (none detected), against a standard of less than 2 PPM (for O2-compatible air). "ND" is definitely what I want to see, as 2 PPM has a partial pressure equal to about 10 PPM at 160', but I've never thought about a reasonable limit. (160' is my own personal limit on air. Any deeper than that and the air is diluted with He, which would lower any PPCO in the air.)

You might search for anything Simon Mitchell has had to say about it or tag him if you can't find anything relevant. Duke Diving Medicine is another great credible source.

 

[DandyDon]

LFMarm's charts in post #227 are right on, but let me add...
Table 1 states that on the surface 30-60 ppm is the maximum safe level, therefore 60 is the actual max!
Table 2 shows that 10ppm at the surface converts to 50ppm at 130 feet down.
So even if you're planning a shallower dive, allow for the possibility of going deeper for some reason and make 10ppm at surface your max even tho some counties allow 15ppm.

 

[divingdayz]

Two ill divers makes a high suspicion for contaminated fills. Awaiting more info.

It certainly sounds like it.

 

[rlh739]

I have another question, specifically about my new Forensics Detectors CO monitor.

In addition to using it to spot-check SCUBA tanks, can this same device be used for continuous monitoring, such as leaving it on overnight in a hotel room, or on in a transport vehicle, in case CO levels become elevated?

 

[dberry]

I have another question, specifically about my new Forensics Detectors CO monitor.

In addition to using it to spot-check SCUBA tanks, can this same device be used for continuous monitoring, such as leaving it on overnight in a hotel room, or on in a transport vehicle, in case CO levels become elevated?

I don't know your model, but the detector I use (see #126 in this thread) is will monitor CO levels and keep track of the maximum value. Check your manual.