[cperciva]

He's lucky that he could smell it! About 1/3 of the population lack the gene -- including my grandfather, who discovered this when performing an industrial reaction with cyanides and being alerted by someone at the other end of the room yelling that he could smell cyanide.

[adonovan]

Hydrogen sulfide generally repels people to a safe distance due to its strong smell of rotten eggs, but in very high doses, such as when the police open a car door after an H2S suicide within, it quickly disables that very sense of smell.