[music321]

My brother claims to have health problems since being exposed to an old battery for several hours that was undergoing a recharging.  The liquid battery, for a small tractor (I don't have the battery, I don't know any other details) ultimately did not take a charge, and gave off a noxious sulfur-smelling gas.  I'm guessing it was evolving H2S.

I realize that H2S is highly toxic.  A friend dismisses my brother's exposure saying, among other things, that he has had significant H2S exposure in the lab with no lasting ill effects.

He states that since he has been exposed to vapors as a result of opening an 18M bottle of H2SO4, he has been exposed to H2S gas.  I disagree.  To my knowledge, no H2S is evolved from H2SO4 from an aqueous solution.

Further, he states that he (my friend) has been exposed to chronic low-levels of H2SO4 in labs without ill effect.  He claims that since he's smelled a rotten-egg smell on many occasions, this is evidence.  I wonder if he actually smelled something else.  I am incredulous that he has been exposed to as much H2S as he claims to have been without suffering lasting ill effects.

When answering, please give credentials.  I plan to show this thread to my friend.  Please be honest about the credentials, though.  If you have none, but can show how you arrived at your position logically, that's all that really matters.

Further, my friend states that H2S can react with H2O to produce H2SO4.  It seems that under STP without the addition of electric current, if this were to happen, it would happen at such a low rate as to be negligible.  Thoughts?

Thanks.

[Borek]

A friend dismisses my brother's exposure saying, among other things, that he has had significant H2S exposure in the lab with no lasting ill effects.

Different people react differently, even assuming he was exposed to H₂S without ill effects it is not a proof of anything.

Further, my friend states that H2S can react with H2O to produce H2SO4.

It can't. You need a relatively strong oxidizing agent for that.

[music321]

thanks for the response.  out of curiosity, when fumes come off of a bottle of high molar h2so4, what exactly is becoming airborne?  is it h2so4, an ion form of this, a degradation product, or all of the above?

[discodermolide]

thanks for the response.  out of curiosity, when fumes come off of a bottle of high molar h2so4, what exactly is becoming airborne?  is it h2so4, an ion form of this, a degradation product, or all of the above?

The fumes are probably SO₃.

[ajkoer]

People with lung and allergy related issues should not be around chemicals period. SO3 is an extreme irritant (actually dissolves flesh), and H2S is a relatively milder, but still a very toxic (a bit better than HCN) uncle. Also, avoid Cl2O/Cl2 fumes from NaOCl (Bleach).

[fledarmus]

I doubt seriously that either your brother or your friend has been exposed to H₂S in the ways that they are claiming. Neither old batteries nor sulfuric acid give off H₂S fumes, it is much more likely that they were exposed to SO₃. Hydrogen sulfide is present in low levels in human bodies and human metabolic systems will slowly rid themselves of the poison. Toxicities from hydrogen sulfide are almost always acute toxicities, and H₂S smells terrible at much lower concentrations than it exerts toxic effects. Indeed, one of the first effects of H₂S at sub-toxic concentrations is that it deadens the olfactory nerves and you can't smell it anymore.

I'm not saying that your brother isn't suffering from environmental effects caused by fumes from an old battery, but it's probably not hydrogen sulfide.