Most every RVer has experienced the rotten egg smell when lighting a propane stove burner in their RV or has heard the expression, “I smell propane.” I am even guilty of saying it. The truth is, propane has no natural odor. What you are smelling is mercaptan, which is added to propane to provide the stink letting your nose know propane is present. Just as mercaptan is added to natural gas, which is also odorless, as a safety measure alerting homeowners to a possible gas leak, it is also added to propane to inform RVers and other propane users of a possible gas leak.
“Propane gas is odorless and colorless in its natural state, so in order to alert users to a leak, an odorant called ethyl mercaptan is added during the distilling process. This sulfur compound gives the gas a rotten egg or skunk oil odor.” Per the late Gary Bunzer, the RV Doctor.
What is mercaptan?
What is mercaptan? Per this source: “The gas is an organic substance, made of carbon, hydrogen and sulfur, and is found naturally in living organisms, including the human body where it is a waste product of normal metabolism. It is one of the chemicals responsible for the foul smell of bad breath and flatulence.” Now you know why your nose is perceptive to the smell of mercaptan! Since it is also a waste product of the human body, this is why it is also mistaken for a smelly holding tank.
Mercaptan is heavier than propane
Another interesting tidbit concerning mercaptan is that it is heavier than propane and settles to the bottom of your propane cylinder. This is why the odor becomes stronger when the cylinder becomes low on propane. This can serve as a good indicator that it is time for a refill for those that don’t have gauges on their propane cylinders.
Finally, don’t rely on the odor alone to alert you to a potential propane leak, as RVtravel.com’s own Dustin Simpson explains here.
Hopefully this month’s installment of Fact or Fiction provided you with a little useful information you didn’t know.
Test your knowledge some more with these previous Fact or Fiction questions:
- A propane furnace emits lots of moisture
- If you see these on your RV, do not use it in winter!
- Outside temperatures can be too cold for an RV refrigerator to cool
- Never plug in with a 20-amp extension cord
- Doing THIS is the number one cause of RV fires on highways
Now, some questions for you:
- Is there a reoccurring half-truth you keep seeing online that you would like to see addressed?
- Were you taught something by other RVers that turned out to be bad advice?
- Have you recently read something that left you wondering, is that true?
- Do you know something to be true, but none of your RVing friends believe you?
Please share your comments using the comment box below and we will do our best to provide the facts in a future Fact or Fiction entry.
Thank you, Dave!
Question is missing key word to support your answer…NATURAL. As asked, the answer is yes there is a odor. Propane can’t be purchased without the additive so pointless discussion
Trick question, not useful at all. We all know propane has no intrinsic smell, but you can not purchase it, or even find it anywhere without having the smell producing chemicals to it. So yes, any propane you or anybody you know that ever used it does indeed have a strong smell.
I dealt with corrosion issues at power plants and occasionally hit seminars with guys from the gas industry. They told me one of the ways they looked for leaks on major lines was to watch for buzzards. The mercaptan smell which also comes off decaying, dead animals will draw them.
How manyRVers have propane that does not have mercaptan added to it?
None, this story is a waste of electron space.
Agreed. Of course propane Gas that we use/buy has an odor for good reason. Wasted my time too!