Bad Air

[Misty]

Before you ask it was not the curry from the night before.
I think I got poorly from Hydrogen Sulphide - It made me ill for a couple of days- nausea, vomiting, I slept for 30 hours and even today I still feel a bit wobbly. Its easy to say in hindsight what we should have done but we were excited by the dig. As I had smelt eggs on previous visits but not very strongly and we had all felt OK so we were not so concerned this time. We had discussed lack of oxygen but not Sulphur present. I have done some reading on this now I'm not so sure it was only lack of oxygen. We also thought maybe we were imagining it - I've heard bad air can cause poor judgment.   :greed: After about 3 hours We all left because a couple of us felt ill but initially put it down to Carbon Dioxide instead due to re-breathing air- on reflection it seemed that where the mud was hitting the wet floor further down that the smell was occurring.  I think I got it the worst because I was behind and below the digger in a fairly low level section filling bags of now wet soil where there is very little air flow through. Once up by the dig face I started to hyperventilate as did my digging partners which is when we left- not sure though this felt like lack of oxygen at the dry dig face. Are there any distinguishing differences between carbon dioxide and Hydrogen Sulphide poisoning? What happens when carbon dioxide and sulphur dioxide mix- I am not a scientist.  I appreciate we will need to also think of ways to ventilate the dig, have shorter visits and leave longer periods between visits. Any knowledge/tips/experience welcome- disapproval not as I will still keep going there.

 

[andymorgan]

Sounds like it may be Hydrogen Sulphide due to the eggy smell: http://en.wikipedia.org/wiki/Hydrogen_sulfide

I hope you are feeling better now!

 

[Misty]

Yes thanks Andy back to work tomorrow yesterday was the worst

 

[Chris Lank]

Other than hyperventilating at the dig face I suffered no ill effects.  I also never smelled anything bad, although I know that a few of you did.  It is odd because when I was bagging up behind Mr Misty, I never noticed anything except the rocks and mud that he was hurling down on me.

 

[graham]

Is anyone going to be so kind as to tell us all where this went on?  :-\

 

[anfieldman]

Is anyone going to be so kind as to tell us all where this went on?  :-\

Might do when we make our incredible breakthrough! 

 

[Brains]

The hyper ventilating and your post on here screams CO2 not H2S as this altho smelly at low concentrations will not really harm you. At a dangerous level you will NOT smell it and will drop dead. NB not everyone can actually smell it anyway. H2S is almost never found in natural caves or metal mines, but only rarely in coal mines and occasionally oil wells. It may also be caused by rotting timber, especially pressure impregnated timbers ie old railway sleepers/ telegraph poles.
The CO2 can really only be reduced by ventilation - this can be caused by a number of things including (body) heat.
If a natural cave try lighting a candle - no light, go home!
Get well soon and take a canary / flame safety lamp! ...or try and smoke

 

[Misty]

Chris I dont know if Ive got just a nasty bug but I felt 100 % fine before but felt dreadful later on being sick etc.  Gary smelt it and could not dig behind me- it was not me honest. I think we could take some testers they use in diving for checking oxygen level etc.

Maybe the vomitting was caused by the cake we had for pudding in the pub afterwards- Thanks Chris all the same.

Thanks Brains thats a bit more useful.

 

[shotlighter]

Cheap test for H2S is (apparently) paper dipped in lead acetate solution & dried - it turns black in it's presence.

 

[Peter Burgess]

H2S is almost never found in natural caves or metal mines, but only rarely in coal mines and occasionally oil wells. It may also be caused by rotting timber, especially pressure impregnated timbers ie old railway sleepers/ telegraph poles.

Brains, please don't say it's rarely found in old metal mines! There's plenty of rotting wood and anaerobic nasty puddles in old mines of any flavour where the gas could be present, surely?

 

[Misty]

Peter what can you tell me about the smell we encountered of bad eggs- this I have read the following "Hydrogen Sulfide in low concentrations smells like rotten eggs (but not so noticeable at high concentrations).  Sulfur-reducing bacteria present in ground water use sulfur as an energy source to chemically transform sulfates to produce hydrogen sulfide. The bacteria uses sulfur from decaying plants, rocks, or soil. They exist in environments that are oxygen deficient. It is colorless, heavier then air, and toxic.  It?s best to leave when a smell of rotten eggs is detected, if well ventilated it should not be a problem." in Oxygen Deficient Caving and Other Hazards By Nate Newkirk. Would this be possible if the material we are removing was formed from ancient organic waste? Brains you say "almost never found in natural caves" so why is it metioned so often in relation to bad air in caves - but surely it must be more frequent?

 

[Wolfart]

Go steady Misty you want to see your first anniversary.
Glad to hear you are feeling better.
P.S hope to see you ooop north in May if Trini has her baby by then

 

[andymorgan]

It probably is bacteria breaking down organic matter, producing H2S (Hydrogen Sulphide). The organic matter could be ancient, and the pockets of H2S trapped for a long time in it, or it could be washed in more recently.
I don't really know the dig site, but I may experience it first-hand this weekend although you aren't really selling it to me  :yucky:

 

[Peter Burgess]

Peter what can you tell me about the smell we encountered of bad eggs- this I have read the following "Hydrogen Sulfide in low concentrations smells like rotten eggs (but not so noticeable at high concentrations).  Sulfur-reducing bacteria present in ground water use sulfur as an energy source to chemically transform sulfates to produce hydrogen sulfide. The bacteria uses sulfur from decaying plants, rocks, or soil. They exist in environments that are oxygen deficient. It is colorless, heavier then air, and toxic.  It?s best to leave when a smell of rotten eggs is detected, if well ventilated it should not be a problem." in Oxygen Deficient Caving and Other Hazards By Nate Newkirk. Would this be possible if the material we are removing was formed from ancient organic waste? Brains you say "almost never found in natural caves" so why is it metioned so often in relation to bad air in caves - but surely it must be more frequent?

Rotten eggs = hydrogen sulphide = potential danger.

Sulphuretted hydrocarbons have a similar smell - not so sure of their toxicity though. I suspect they are not so dangerous - I think that's the gas I personally seem to produce on most caving trips, especially when struggling in a tight space.  :-[

 

[anfieldman]

I think that's the gas I personally seem to produce on most caving trips, especially when struggling in a tight space.  :-[

http://members.aol.com/z321go/FartFire.jpg

 

[Peter Burgess]

I think that's the gas I personally seem to produce on most caving trips, especially when struggling in a tight space.  :-[

http://members.aol.com/z321go/FartFire.jpg

That bloke's got two 4rseh01es!

 

[Pitlamp]

I don't agree with Brains when he says that hydrogen sulphide isn't that common in natural caves. Apart from anaerobic microbial decay of organic substances (which can happen anywhere if the right conditions exist) many limestone areas of the world are indirectly influenced by nearby volcanic activity. This can cause a particularly dangerous hydrogen sulphide build up in airbells and so may be especially hazardous for unsuspecting divers who surface in them. I think the Italians have done quite a bit of work on this, if anyone particularly wanted to find out more.

The Americans never did learn to spell sulphur, did they? 

 

[Ed W]

Misty,

I have no experience of Hydrogen Sulphide (as much as some of my caving mates may suggest that I am a mobile generator of it), but quite a bit with CO2.  Our current dig has had significant problems with CO2, and we have found that the best way of dealing with it has been to suck air out from the dig face to the surface, so forcing fresh air into the cave.

We do this with a normal houshold hoover on the surface, hooked up to 40m or so of hose to the dig face.  This is powered by a generator.  Within a few minutes of being turned on the air at the dig is noticeably better.  We did this based onthe advice of other diggers who had found it effective in the past.

All the best, and good luck.

 

[Tartan Amy]

Misty,

I work in the oil industry and in the Middle East hydrogen sulphide (H2S) is pretty common in our limestone and dolomite reservoirs.  We are trained to give it a healthy respect - it is nasty on just about every front - poisonous, corrosive, explosive....... The symptoms you descibe are typical - I've been exposed to it in low concentrations and I felt sick, headaches etc.  It is also common for people to have different rections.  If you smell it - best get out and test for the concentration (Draeger tubes or personal gas detectors if you can get hold of them) and get some ventilation sorted out for your dig.
It may accumulate wherever a mixture of hydrocarbons and sulphur are found - in my case we look out for it in oil and gas fields.  However, as stated by other posters, there are a variety of organic sources where H2S can be found, eg mines, swamps and sewers. H2S is a natural by-product of organic decay and so if it is within the sediment infil that you are excavating, you may just be disturbing localised pockets.

Here's a few facts:
Other names (if you want to research on the internet) - hepatic acid, sour gas, sewer gas, sulfur hydride, dihydrogen monosulfide, sulphur hydride, stink damp, sulfureted hydrogen.

H2S has a distinctive offensive smell, similar to ?rotten eggs?. It is so toxic that it disables a victim?s sense of smell on exposure to gas concentrations above 150 parts per million (ppm), so it could be fatal to rely on your nose as a detection device. Individual perceptions range from 0.1 to 500 ppm, which is why you can smell it but your mate may not. Once you stop smelling it, time to get out rapidly. Inhalation of a single breath at a concentration of 1000 ppm ( 0.1% ) may cause coma and death.

It is heavier than air so it tends to settle in low lying areas. Mixed with the right proportion of air or oxygen (4% by volume), H2S will explode.  Of course, you'll be dead at this concentration anyway.

It is an irritant, and you'll notice the effects on your mucous membranes especially eyes.

Hope that doesn't put you off, but better to be aware of how nasty this stuff can be....

 

[gus horsley]

H2S is probably fairly common in mines but only rarely in dangerous concentrations.  There was an incident in Cwmystwyth Mine about 20 years ago when a dig broke through into old workings and one member of the party was rendered unconscious as soon as they entered the area.  He made a complete recovery as soon as he was hauled out of the extension but the group wisely left the discovery alone for a while until the gas had dissipated.