NASA sets new hydrogen sulfide exposure limits for space missions

H2S is an incrediblely dangerous gas. It can kill some people as low as 100 parts per million after long term exposure. It has the nefarious side effect of paralyzing your olfactory nerve making you think the exposure danger has subsided because you can no longer smell the rotten egg smell it has. OSHAs recommended exposure limit is 10 ppm with a max exposure of just 20 ppm,1 ppm for 8 hours and 5 ppm for 5 minutes. Even at those low exposures it can cause memory loss, lapse in judgemen, bronchial constriction, dizzyness and digestive problems. At 200 to 300 ppm most people will die in under an hour, 500 ppm loss of consciousness in less than 5 and death under 30 minutes, anything over 700 ppm is near instant death. Almost every company I have worked for in the oil and gas industry has a zero exposure policy. H2S is also extremely flammable and can explosively combust at concentrations of just 4%. It’s very heavy so it will pool in low lying areas even with low lunar gravity.

Yet another reason I’d never qualify as an astronaut 😔