FL/GA PLS., post: 426665, member: 379 wrote: For the upcoming crop of young Surveyors:
"Hydrogen sulfide is a highly toxic and flammable gas. Because it is heavier than air it tends to accumulate at the bottom of poorly ventilated spaces. Although very pungent at first, it quickly deadens the sense of smell, so potential victims may be unaware of its presence until it is too late. H2S arises from virtually anywhere where elemental https://pubchem.ncbi.nlm.nih.gov/compound/sulfur&apos ;">sulfur comes into contact with organic material, especially at high temperatures. Hydrogen sulfide is a covalent https://pubchem.ncbi.nlm.nih.gov/compound/hydride&apos ;">hydride chemically related to https://pubchem.ncbi.nlm.nih.gov/compound/water&apos ;">water (H2O) since https://pubchem.ncbi.nlm.nih.gov/compound/oxygen&apos ;">oxygen and https://pubchem.ncbi.nlm.nih.gov/compound/sulfur&apos ;">sulfur occur in the same periodic table group. It often results when bacteria break down organic matter in the absence of https://pubchem.ncbi.nlm.nih.gov/compound/oxygen&apos ;">oxygen, such as in swamps, and sewers aka manholes (alongside the process of anaerobic digestion)."
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From my long-ago college chemistry, H2S forms a strong bond with the hemoglobin molecule and prevents it from carrying oxygen. Its action is very similar to that of the hydrogen cyanide gas that was formerly used in executions. There isn't any antidote, although a massive blood transfusion might help if given in time.
I remember a couple of H2S deaths that took place about 20 years ago. One was a deputy sheriff on the Jersey shore who went down in a pit containing rotting organic material. Another was a fisherman in Florida who went into the hold of a ship where something must have been decaying.
Methane isn't actually poisonous but can crowd out the oxygen from a confined space and cause asphyxiation. Methane, unlike H2S, is lighter than air, so it's less likely to accumulate in manholes and other low places.
RPlumb314, post: 427942, member: 6313 wrote: Methane isn't actually poisonous but can crowd out the oxygen from a confined space and cause asphyxiation. Methane, unlike H2S, is lighter than air, so it's less likely to accumulate in manholes and other low places
But if it does dont open the MH and throw lit charcoal in it. This qualify's for a Darwin Award, although sad.
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I spent 5 years surveying for the oil and gas industry. Hydrogen Sulphide is not only deadly serious, the more you learn about it, the more horrifying it is.
After leaving the northern BC oil patch in six months the chronic canker sores went away, and in 3 or 4 years, my sense of smell returned.