Became extremely sick during dive...Possible bad gas?

[whiskaz]

First of all let me say that if this isn't the appropriate forum for this then I apologize.

Dive Profile: 32% Nitrox (was supposed to be the 1st dive of a 3 dive day), Long snorkel out (200-250 yards), planned depth of 80 ft, with planned bottom time of 30 min. Actual max depth 50 ft, bottom time of 17 min. Tank was filled at the same time as three others (total of 4, all 32% Nitrox). Two were used the day prior with out any issues and my buddy used the other tank with no issues.

Summary: Snorkeled out with no problems. Dropped down and began exploring the reef (this was a new dive site for both my buddy and I). After about 15 min I began to experience an extreme headache. It was bad enough that I signaled my buddy and thumbed the dive. After reaching the surface we swam in on SCUBA rather than snorkel. After reaching the shore my my head was still pounding, I vomited up my breakfast and was feeling fatigue. We drove back to the house where I vomited again and I slept for about four hours, I had someone to check on me regularly, after which I felt fine other than a slight headache. Felt well enough to dive the next day and completed two dives with no issues.

My questions: How likely is it that one tank out of four was contaminated even though all were filled at the same time?

Would it be recommended that I get the tank's contents analyzed by a third party?

If so how would I go about doing this?

If not bad gas, what other factors could account for this?

FYI, other than a tight mask during my certification dives I have never had a headache or felt sick during or after a dive.

 

[mddyver]

If not bad gas, what other factors could account for this?

My guess would be CO2 toxicity, caused by over breathing your snorkel on a long surface swim. If you were exerting yourself enough to elevate your breathing rate and not completely clearing your snorkel of your expelled CO2 you run the risk of breathing an increasing concentration of CO2 in the dead air space between the mouthpiece and the top of the snorkel.

Symptoms include severe headache and nausea.

I learned this the hard way.

Mike

 

[tstormdiver]

Though it *may* be possible to have 1 contaminated tank out of 4, However, it is very highly unlikely. I concur that it sound more like a CO2 hit while snorkeling out to the site or even during part of the dive, depending on your work load & breathing rate.

 

[h90]

where they fill the tanks.....can you see the place?
If for example painting something. It smells a little bit but no harm on the surface, under pressure it can the gas if compressed can harm.

 

[DevonDiver]

I'd guess at CO2 hit also.... especially as you state there was a long surface swim before descending.

Did you take some time to calm your breathing and clear your lungs after the surface swim and before switching to scuba?

 

[Doubler]

Question, wouldn't the increased O2 in the Nitrox mix help alleviate the CO2 hit? You are taking on an increased O2 supply while exhaling CO2 so unless something is adding too or maintaining the CO2 at the same level I don't see the snorkel out as the issue but rather contaminated air.

 

[DandyDon]

Who knows? Lots of possibilities really. The CO2 & snorkel theory works to a point but that long? Especially since the symptoms started 15 minutes after switching to scuba and persisted even after returning on scuba rather than snorkel? Might have more to do with your personal breathing...??

It's not so much "possible to have 1 contaminated tank out of 4" as to ask could one of the tanks be that much more tainted than the others? If they were all hooked up to the compressor at the same time for simultaneous filling, then probly not. If they were all filled the same day at different times, the possibilities increase.

After reaching the shore my my head was still pounding, I vomited up my breakfast and was feeling fatigue. We drove back to the house where I vomited again...

I take it you neither called DAN nor went to the ER? I don't like going to a doctor either, but that sick - wow. :shocked2:

A good dive shop would have gas sampling for testing equipment on hand even tho Padi no longer requires quarterly testing, but then the shop is in control of the test and the resulting info and you can imagine what the shop's lawyer would advise.

Affordable, portable CO analyzers are so newly available to the sport that they are still all too uncommon among divers. Do you know any tech divers there? They might have one. That's the only way to rule it out.

 

[TSandM]

It's fairly unlikely that one tank of four would be contaminated.

I agree with the CO2 theory. And the fact that you were breathing Nitrox not only doesn't alleviate the CO2, but may aggravate it. There is some evidence that breathing elevated ppO2s allows some people to tolerate higher pCO2s without air hunger.

Oxygen and carbon dioxide are subject to somewhat different influences in gas transport in the lungs. Oxygen is carried on hemoglobin, so there is a second equilibrium in addition to the simple one of diffusion (and diffusion across the alveolar membrane is the limiting factor in O2 transport, because O2 isn't very soluble and diffuses more slowly). CO2, on the other hand, is highly soluble and diffuses quickly, so the pCO2 is, to all intents and purposes, determined entirely by the alveolar minute ventilation, or the amount of gas you move in and out of your lungs.

The problem with a snorkel is that it adds to what is called the "dead space". This is the volume of the column of air you have to move back and forth with each breath, but which doesn't involve the alveoli, and therefore isn't participating in gas exchange. Normally that dead space is your trachea and your large bronchi. When you add a snorkel, you just about double the length of your trachea from a functional standpoint. That's a big increase in dead space, and in breathing resistance, too. As a result, it's quite difficult to maintain an adequate minute ventilation on a snorkel, particularly when exercising, as you do when you surface swim. Snorkels are best used by people who are sightseeing -- moving slowly, and not continuously.

So you probably began your dive with an elevated pCO2, and never blew it off effectively during your 15 minutes underwater. I have to tell you that the worst headaches I've ever had in my life have been CO2 hits, and I thought I was going to lose my lunch, too.

 

[Mike Boswell]

"As a result, it's quite difficult to maintain an adequate minute ventilation on a snorkel, particularly when exercising, as you do when you surface swim. Snorkels are best used by people who are sightseeing .."

Lynne - I am wondering if the lung volume of the diver is a factor here. It seems to me that this "snorkel dead air" effect would be more prounounced with small females than with large males.

 

[whiskaz]

where they fill the tanks.....can you see the place?
If for example painting something. It smells a little bit but no harm on the surface, under pressure it can the gas if compressed can harm.

I can see it. It doesn't look like painting or anything is going on.

I'd guess at CO2 hit also.... especially as you state there was a long surface swim before descending.

Did you take some time to calm your breathing and clear your lungs after the surface swim and before switching to scuba?

Surface swim was nice and slow. We did take a couple of minutes before descending.

It's not so much "possible to have 1 contaminated tank out of 4" as to ask could one of the tanks be that much more tainted than the others? If they were all hooked up to the compressor at the same time for simultaneous filling, then probly not. If they were all filled the same day at different times, the possibilities increase.

I take it you neither called DAN nor went to the ER? I don't like going to a doctor either, but that sick - wow. :shocked2:

Affordable, portable CO analyzers are so newly available to the sport that they are still all too uncommon among divers. Do you know any tech divers there? They might have one. That's the only way to rule it out.

It would have been more accurate for me to say that I dropped them off at the same time and picked them up the next day. I personally do not know if they were actually filled at the same time.

I didn't go to the ER. The only military one on island generally has a 4-6 hour wait in the middle of the week, and if you go to a Japanese one you better have cash in hand and be able to prove you were just about to die if you want to get reimbursed, so I decided that if I would go if I didn't feel better after resting.


I appreciate all the suggestions and comments. A CO2 hit makes the most sense to me (I don't know why I didn't think of it before) but I will be trying to find an English speaking dive shop that can analyze the gas just for my own piece of mind.