Propane and Odor Fade

Lisa Dejong, The Flint Journal

Six children, ranging from 2 to 19 years of age, were killed when this rural Michigan house exploded early on the morning of September 3, 2005. If you use propane in your home or business, this kind of incident could happen to you. Here’s what you need to know about propane and odor fade.

This information has been moved and updated.
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24 Responses to “Propane and Odor Fade”

  1. Joshua Shoulders says:

    Dear Sir,
    I am giving a persuasive speech for competition in the NCFCA on removing propane gas from residential zones. Those six children that you mention at the beginning were very good friends of my family and mine (Joseph and Nehemiah were my best friends). Thank you for putting the dangers of propane out for the world to see. I was wondering if you could tell me what date this article (Propane and Odor Fade) was written. Also, if you have any additional information I could look at or websites, books, and articles to which you could refer me, I would be very thankful to receive that information. Thanks again!

    Sincerely,
    Joshua Shoulders

  2. Bruce says:

    The bulk of the work on this page was completed in September 2008, and it is updated as needed. I don’t know of other websites or sources of information that have not already been mentioned here. I suggest you download and read the documents linked above. I’d be very interested in hearing what you have to say about propane, and perhaps adding your material in whatever form — written, audio or video — to this page.

  3. Eric Svensson says:

    Joshua should realize that propane is one of the safest and most widely used fuels on earth. One widely used altenative, charcoal, is so dangerous it should never be ued inside any buildings. The tragedy of the six children is not the gas’s fault, and “removing propane gas from residential zones” would result in the children of most parts of the world suffering from the effects of coal fumes, carbon Monoxide, oil smoke, and other pollutants created by much dirtier and more dangerous fuels. Helping people detect gas leaks, and showing how to use propane safely is a very useful way to spend his time.

  4. Dave says:

    Does odorant fade occur with natural gas as well? I understand that ethyl mercaptan is used as an odorant in it, too.

  5. Bruce says:

    Good question, Dave. There is nothing unique about the chemistry of natural gas versus propane. Similar mercaptan compounds are used as odorants in both. There are several related mercaptans — ethyl mercaptan, methyl mercaptan, butyl mercaptan, etc. Sometimes suppliers use a blend.

    So it is theoretically possible for odor fade to happen in natural gas, such as if a slow leak percolates up through soil or gas accumulates in a concrete structure. Odor fade doesn’t seem to be as much of an issue, since natural gas is lighter than air. It tends to float up and dissipate, while propane is heavier than the air, sinking and pooling where the odorant has an opportunity to get adsorbed by surfaces.

    Also, there are the same issues of impaired olfaction and odor blindness. If a person is unable to smell natural gas, he or she will be unable to smell propane. It’s a good idea for people to check their sense of smell. Your local utility company or gas supplier has free mercaptan scratch-and-sniff cards they’ll give you for the asking.

    Odor fade is not likely to happen within natural gas distribution systems. Natural gas flows continuously through pipes and lines, while propane is stored in tanks that are depleted and refilled.

    Unlike natural gas, propane is stored in the liquid phase and used in the vapor phase. There are issues of vapor pressures and boiling points and such that affect the concentration of odorant in propane.

  6. Ronda Eddy says:

    I had a propane leak in the crawlspace of my house. We have fixed the leak but the propane has sunken into the dirt, is there anything I can do to remove the odor?

  7. Bruce says:

    Glad to hear the propane leak was detected in time. Dirt and porous masonry surfaces adsorb mercaptans like a sponge. The mercaptan is in the material. Once the gas is gone, the odor itself is harmless. The area smells vaguely of gas. I’m not a chemist or engineer, but if it were my home, I’d find ways to mitigate the odor. Perhaps you can remove a few inches of dirt and/or cover it with clean topsoil. If the crawlspace is open to the outside, I’d rinse what I could with a hose to remove surface dirt from the foundation, supports and beneath the beams. I’d go to Home Depot and buy a pump sprayer with a long nozzle, like the kind used by home exterminators, and fill it with a few bottles of cheap hydrogen peroxide from the dollar store. Peroxides neutralize sulfur-bearing compounds, and it may work on mercaptan. I’d spray as much as I can, and for good measure would follow up with a spray of something like Febreeze. You might also try sprinkling activated charcoal, which is sold with pool or aquarium supplies. But this stuff is jet black and messy; not a good idea if you have pets that might get in there. And as long as you’re in the crawlspace, install a propane detector — that’s the dangerous area where gas can accumulate.

  8. C.Martin says:

    Bruce, I was very interested in the results from the canadian study on oxide absorption and I was sad that the document you have posted doesn’t inlcude the tables. I found one that is posted on the internet that does and I thought I’d pass it along incase anyone else was interested.

    http://www.cpsc.gov/library/foia/foia02/os/propanept2.PDF

    Thanks for all your work on the subject!

  9. Bruce says:

    Thanks for the document, Courtney. I’ve replaced yours for the inferior version I had linked. I appreciate any other documents or information you care to pass along.

  10. Renee MacKenzie says:

    Dear Bruce:

    Just another note to say thank you again for your work in this area. I wrote you about two and a half years ago after suffering burn injuries in a house explosion. I do my own small part in educating people about the dangers of odor fade and propane but it seems So Little compared to the potential devastation.

  11. Brooke Brockbank says:

    We live in a rural area and have a propane tank- only for fireplace. A few days after we installed the propane tank we smelled propane if we were standing right next to the fireplace. It was very strong. We called and had someone come check it out- when they got there the smell was not present anymore (of course), but they did many tests on all the pipes and said they were convinced there was no such leak. They also said that maybe we smelled something, but propane would sink and that it would be near the floor and not in the area around the fireplace. Well the smell keeps coming back very strong- it is the propane smell, but whenever I smell the floor, i smell nothing. Should I be concerned. Sometimes I can smell it when I walk in the room. But again it is never around the floor by the fireplace. Can you ease my worries about this?

  12. Bruce says:

    It’s hard to say. I’m not a propane expert or an engineer. A propane system can be tested for leaks, which I presume was done by person who came out to your house. If you aren’t confident of that person’s assessment, have your system checked by a qualified technician recommended by your propane distributor. It could be that you have a batch of propane that is heavily odorized, or that you have a very sensitive sense of smell. The best way to ease your worries is by installing a propane detector, which goes in the lowest spot in your house — a basement or crawlspace, if you have one.

  13. Ramsey says:

    Holy hell, Bruce. Never seen that opening photo before. Glad to know you’re on the case…..

  14. Michael James says:

    I have read that if you test for leaks with a soapy substance to see any bubbles leaking, that that is fine.

    HOWEVER, NEVER, EVER TEST WITH ANYTHING THAT HAS AMMONIA IN IT. It will cause any copper or brass fittings to deteriorate very fast. You will end up with a deadly situation.

  15. Ken says:

    Since there are some containers and situations in which the mercaptans do NOT break down or disappear, it seems that requiring all propane-handling equipment to be built to these standards would be a reasonable starting place. And if it isn’t known what they are, there’s some pretty basic science to be done – but there’s no reason to expect either the science or the technology to be outrageously difficult or expensive. About the only place you CAN’T stop odor fade is propane being filtered through soil.

  16. Rod Allen says:

    I was just looking over your list of propane accidents. I was involved in a so called propane flash fire and ended up spending a week in a burn center and several months of healing which is still on going. I was fortunate enough to have the knowledge to be able to recover the gases that I was purging. After analysis it was found that I had excessive amounts of ethane in the propane mix. Its unknown the frequency of this problem in explosions as this type info is sparse.

  17. Patti Nick says:

    The owner of a gas station across the street from my subdivision wants to expand by installing a 30,000 gal above ground bulk propane tank next to the gas station and an inventory of 6 – 12 500 gal. LP tanks for commercial sale or rental. He will be having bulk trucks refill at this site for delivery to his customers. On the other side of the street from this proposal is a developement of 30 condos and an apt. bldg. with 18 units. At the end of the street is a 70 bed nursing home. This project is at the top of a t-intersection. We could not evacuate the area if something went horribly wrong. He is requesting a Conditional Use Permit from the county to do this. What is your opinion?

  18. Carrie says:

    My parents have propane that heats their home and also have a propane stove. When my husband and I were visiting, my mother was saying she could always smell propane and even had some guys out to the home to check but they said everything was fine. There was one day when we were there both my husband and I could smell the propane very stronge in the kitchen and I had to leave the house because it was giving me a headache and I started to feel very dizzy from it. I then believed my mother that there was something wrong. So by the time my father came home I told him of the stronge smell but it was no longer there. Can the propane smell leave but still somewhat be in the house and effect someone who has been feeling very ill for quite some time? And can it effect someone else who also lives in the home but has gotten so used to the smell they think there is nothing wrong?

  19. Russ Arpasi says:

    Lightning hit the gas line coming into our house and caused a fire in the wine cellar @ the point where the gas line blew out. The fire in the cellar was hot enough to warp the steel truss and metal pan which supports the concrete above for the garage. We were not @ home when this occurred. Approximately 250 gallons of propane was released into the house. We returned after being gone for four weeks and the gauge on the gas tank was on zero. We called the gas company to come check the gas lines and fill our tank. The gas truck driver stated that he would need to send a leak crew the following week. We told him that it was impossible for us to have used that much gas in the previous four weeks as we had not even been there. We felt that there must be a huge leak somewhere. The driver proceeded to fill the tank with approximately 275 gallons of propane and left. A large majority of this new tank of gas also leaked into the house before the problem was discovered. The insurance company is attempting to clean our house and all of our belongings with an ozone treatment. It has been a month since this occurred. The smell is still there. Does anyone know how to get rid of this odor? Should we be concerned about the absorption of the gas into the wood, concrete, sheetrock, furniture, etc.? Will this continue to be a health hazard for us? We went to a doctor and have been told that our lungs are functioning @ about 1/3 of their normal capacity @ this time. We have been prescribed steroids to help with healing. We are desperate for any answers concerning the absorption of the gas/chemicals into the building components and furniture. Can this be removed along with the odor or will the gas and chemicals always be there? Also: should we seek more thorough health exams?? @ this time, we are still not residing in the house as they are using ozone treatment as their major remedy. Are there any websites that can offer assistance??
    Contact Cell- 828-421-3751
    Thank you

  20. Deborah Mckee says:

    I had a rattle snake problem and used Dr Ts Snake away and sprayed ammonia under my house. I heat with a propane fireplace. The snake away contains sulphur. Is this dangerous?

  21. Ken says:

    Hi is there a legal or monitored time frame that a propane company has to respond to an Oder complaint? I thought I had a leek but it was sewage instead. Now the company wants to charge me for coming out. Not very happy. Any thoughts?

  22. Christine says:

    We have a propane insert in our fireplace. It was recently inspected to ensure that all was in working order. The inspector seemed to be quite thorough and it check out as ok. However, I am still smelling something. The tank is full and all the burners appear to have flames. Could a propane insert check ok and still have an after-burn smell?

  23. Erin says:

    I’ve had an outdoor fire table that runs on propane for two years. I have the fake logs inside the pit that came with the set. Ever since it’s initial lighting, the fire burns great but leaves the most unappealing smell. I’ve wondered if there are other kinds of logs on the market which may leave a “wood” smell, but I’ve found nothing except for firewood (which is a big no no for this kind of device). The smell continues to this day when the fire is lit. Is this usual? Or should there be no smell at all? Thanks in advance for any advice you may have.

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