TIL also - until today, I thought it was just "mercaptan". Turns out there are actually two variants of that:
> Ethanethiol (EM), commonly known as ethyl mercaptan is used in liquefied petroleum gas (LPG) and resembles odor of leeks, onions, durian, or cooked cabbage
Methanethiol, commonly known as methyl mercaptan, is added to natural gas as an odorant, usually in mixtures containing methane. Its smell is reminiscent of rotten eggs or cabbage.
...but you can still call it "mercaptan" and be ~ correct in most cases.
https://en.wikipedia.org/wiki/Odorizer#Natural_gas_odorizers