[alloysteel]

Hydrogen sulfide is the "rotten-egg" smell of decomposing protein. Aitch-two-ess is also used in analytical chemistry as a test for the presence of certain metallic ions in a solution (don't ask me, this bit of knowledge was gained 40 years ago), and the stuff is flammable in the presence of oxygen. It is soluble in water, heavier than air, and is noxious in concentrations of only a few hundred parts per million. It is probably safer to breath gasoline fumes, but nobody, so far as I know, has ever breathed in enough hydrogen sulfide to get a high from doing so. Nausea is much more likely.

[vinylsidingman]

It is probably safer to breath gasoline fumes, but nobody, so far as I know, has ever breathed in enough hydrogen sulfide to get a high from doing so. Nausea is much more likely.

read at ask jeeves 600ppm is deadly,, that's the one that worried my friend the most

thanx for the input

[eastforker]

Many a rough neck has been killed by hydrogen sulfide,in higher concentrations it desenticises(sp) the ability to smell,anything over 10 PPM supplied breathing air is required.Sulpheric acid in a car battery produces H2S when it undergoes charging because it is being heated,alluminun sulfide might act as a catalyst to release the hydrgen in sulphuric acid,not for sure,anyways,sometime harmless chemicals mixed with other somewhat harmless chemical can be extremely dangerous,just like bleach and ammonia.

[mfulstone]

It takes 4 times as much cyanide to kill you as it does hydrogen sulfide.

The first thing that happens after you smell H₂S, is that it begins to anesthetize your sense of smell for it. That's why they call it "sneaky gas" in the oil fields.

Lethal concentrations will only be detectable by smell for a few seconds.