999

[simbrooks]

i think it's interesting that 10/20 ppm is max "safe level," but cigarette smoke
contains 400 ppm, and that is not toxic. at 3000 ppm, the person passes out.

so "poisoning" happens at a higher CO level than 400 ppm, but i can't find anywhere
that says what that threshold level is.

Not sure if this is scare mongering for smokers or not, but i heard once upon a time that due to the filter (orange bit) being the part most smokers hold you actually stop some air from getting into the cigarette, which increases the amount of incomplete combustion of the burning fibres and so the amount of CO is greater than that tested on a "smoking machine" that might be part of such studies.

This may or may not be true, i cant recall the actual source, but i gave up that habit long enough ago that it no longer concerns me.

 

[fdog]

This is stuff our HazMat team has to deal with all the time. When you're looking up the numbers, here's how to interpret them: (simplified)

TLV: Threshold Limit Value. If exposed to this amount for all your life as a "workday" (8/hrs per day, 5 days/week), you will suffer no ill effects.

STEL: Short Term Exposure Limit. An expansion of TLV, that allows an elevated exposure of no more than 15 minutes duration, max of 4 such exposures per day. Again, no ill effects.

IDLH: Immediately Dangerous to Life and Health. At this amount, you will not suffer an "Escape-imparing" symptom for 30 minutes. In otherwords, bad things are happening to you, but you will be able to get away. For CO, this would be unconciousness and/or hypoxic symptoms.

TClo: Toxic Concentration Low. Probabally the most relevant here, this concentration is the lowest known to have a toxic effect. That effect could be a varied as making one feel ill, to causing seizures.

LClo: Lethal Concentration Low. Lowest known concentration to have caused a fatality.

For CO:
TLV 25ppm (ACGIH)
STEL 200ppm
IDLH 1200ppm
TClo 650ppm
LClo 4000ppm/30 minutes

Just looking at the above numbers, while in an alien environment (underwater), the number I'd expect to start having symptoms that would be bad would be around 700 to 1000ppm.

Of course, that's at the surface (1 ATA). Place yourself at 165 feet (6 ATA), and to get equivalent surface ppCO, the cylinder only has to have CO at 117-167ppm.

This is not tough to do. Just running a vehicle in a closed garage has produced over 100 ppm in less than a minute (we tested it). All it takes is old/no CO catalyst filter in the fill station, and the right conditions....

All the best, James

 

[H2Andy]

excellent post, James

thank you

 

[tracker]

A friend of mine got CO poisoning in Cozumel a couple of years ago. He said that he recognized that something was wrong, but didn't know what, so he tried to surface. The DM thought he was having problems getting down, and actually started PULLING him down further. He was able to break free and get to the surface, but when he tried to get on the boat, he passed out. He said he turned beet red in the face, because all of the capilaries (sp?) burst, but otherwise was ok in the long run.

Took him a couple of years to get back into the water.

I've read posts about PADI not being good training compared to other organizations. The replies have been that it's not to be blamed on the org., but how good your instructor is. Sounds like the instructor was just interested in making his money as quick as possible.