The Gas Odor Smell? Ask Annie

Dear Annie, I heard that because gas is odorless a scented toxic chemical is put into it to alert people to the danger of a gas leak. Is this true and what is the chemical? –David, TX

Hi David. Yes, this is true, and I know about it because I happen to be one of the population that is very sensitive to it since it is a recognized neurotoxin and I tend to be sensitive to that class of pollutant. The scented chemical used mostly is methl mercaptan, a chemical in the sulfur family, but some more rural areas use what is a more neurotoxic version. Besides being a neurotoxin mercaptan is a recognized respiratory toxicant. Needless to say, when you smell “gas” it is important to report it right away, both so you don’t get exposed to gas and mercaptan.


Kamia C.
Kamia T.about a year ago

What is amazing to me is that most people don't realize that ANY propane tank, large or small, has an emergency relief valve, to keep it from exploding in high temps. It can let off small amounts of propane and this scent at almost any time.

paul m.
paul m.4 years ago


Marie W.
Marie W.4 years ago

If it smelled good people would think it was air freshener.

Lynne B.
Lynne B.4 years ago

It is instantly recogniseable, stinks like billy oh but has saved countless lives.

Kath R.
Kath P.4 years ago

I can't tell you the number of times over the past 20 years I've smelled gas coming from outdoor meters. One time I smelled it coming from under the ground near an outdoor meter. In all cases the gas company acknowledged that there was a leak and they fixed it. Without the added smell who knows what would have happened.

Sue H.
Sue H.4 years ago

I do not understand Why they couldn't add something that is NOT a neurotoxin, I mean, how hard could it be??

Chris R.
Chris R.5 years ago


Chris R.
Chris R.5 years ago


Elaine Dixon
Elaine Dixon6 years ago

I had heard that too

Odin Torchwood
Odin Torchwood6 years ago

I believe adding this "odour" to gas to be essential as it alerts you to discovering a gas leak instead of suffocating from the gas itself.