In-cab diesel fumes — separating carbon monoxide fact from fiction

| June 27, 2014
First Alert battery-powered CO detectors retail for around $20 at the Home Depot.

First Alert battery-powered CO detectors retail for around $20 at the Home Depot.

We posted a question about using carbon monoxide detectors in truck cabs on the George & Wendy Show Facebook page a couple months ago, and the statement was made that diesel engines don’t produce enough CO to kill you — therefore, detectors inside the cabs weren’t necessary. I had never heard this before, so I did a little research and was really surprised at what I found.

There are two diametrically opposed camps on whether or not diesel fumes are CO-laden enough to kill human beings in an enclosed space. Believe it or not, the trucking industry didn’t have much to do with the most comprehensive studies performed, or the science behind it. A man named Berg wrote an essay declaring it impossible to kill humans in the manner the SS was accused of – CO poisoning through the use of giant diesel engines. As you can imagine, this brought about a huge fervor, and many studies were initiated to disprove Berg’s essay, which was written in 1983, so a great deal of the current information we have about the effects stemmed from these studies.

This story's author, Wendy Parker, writes the George & Wendy Show blog, appearing several times a week on, dispatched from her ridealong position in the truck (though not this particular one) with her owner-operator husband, George.

This story’s author, Wendy Parker, writes the George & Wendy Show blog, appearing several times a week on, dispatched from her ridealong position in the truck (though not this particular one) with her owner-operator husband, George.

Carbon monoxide poisoning has been carefully examined since the 1920s, when the concern for ventilation requirements became an issue, particularly for the New York City metropolitan area and the Holland Tunnel. In the early 1940s, research by Yandell Henderson and J.S. Haldane revealed that an average carbon monoxide concentration of 0.4 percent and above is lethal to human beings after less than one hour of exposure.

Diesel engines run by creating pressure and don’t require the actual spark gasoline engines do; they are also able to process the fuel more efficiently, therefore releasing much lower levels of CO than gasoline engines. A study in 1941, by Holtz and Elliott, found that when a diesel engine was run within the manufacturer’s specifications for fuel efficiency it produced only a small amount of carbon monoxide, not enough to be quickly lethal. However, when the fuel pump was adjusted so that it injected more fuel the carbon monoxide content in the exhaust rose to 0.6 percent. This is a lethal amount.

There are many documented cases of lethal CO events involving diesel engines, and probably more cases that are undocumented, or misdiagnosed. When studies are tasked to gather actual numbers of death by CO intoxication specifically from a diesel engine, the information is often not specified on death certificates, or autopsy reports.

While it’s difficult to gather concise numbers, it’s absolutely certain every diesel engine out there is not running to or tuned exactly to manufacturer’s specifications. That being said, there is most definitely a risk of CO poisoning in the enclosed cab of an idling diesel, especially one with exhaust leaks or issues, which again are often present when the engine is not running perfectly.


Lethal Diesel

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Headache, nausea, and dizziness are the most common complaints of those experiencing higher than acceptable levels of CO. An interesting note is that people idling in warm, sunny places seem to have less instance of intoxication than those idling in a cool, rainy climate. The theory is that barometric pressure keeps the gas close, as the air pressure is heavier and harder to escape from.

Detectors range from $15 to $50 to purchase and can be easily installed in the cab of any truck. It’s recommended to install them lower – about head level when lying in the bunk. Give such an inexpensive piece of equipment, it really is better to be safe than sorry.

  • Mark Upton

    I HAD A 2008 PRO STAR for 18 months. I could not tell you how many times it was in the shop for exhaust leaks. I went to the emergency room 4 times 2 of them documented carbon monoxide poisning.

  • jim stewart

    I guess I’m lucky after driving since the sixties! The non-turbo junk we drove back then blowing smoke black as coal should have killed me dead after a few years if there was such a huge health risk in diesel engines. We all slept at night with no air conditioning in parking lots crammed full of reefers and idling trucks so it amazes me to hear this now. Maybe because the truck cabs are tighter today? That doesn’t make sense either however. I know this diesel particulate scare was created by the Teamsters union funding flawed diesel particulate studies in California in order to force the owner-op’s at the ports out of business with their older trucks so they could unionize employees. Perhaps that’s one problem? It could also be driving along today with the windows down. The outside air is so polluted that it’s killing us in the trucks. I for one believe it’s those dreadful air born pollutants every-time a politician opens his/her mouth that’s doing the real damage. Just listening to the local evening news reporting on our Washington legislators every night gives me a damn headache!!

  • Lee Campobasso

    I agree Jim. I’ve been at it since 1970. I think their problems is with the “new diesel” same with Gasoline,it will make your hand cold and start eating my skin off.

    State of Ca. added something Called MBNA, if I remember right, to their gas almost 20 years ago. They finally had to pull it out of the gas supply because it was being found in drinking water, killing, and showing up in babies. You know lots of birth defects, cancers, that sort or thing

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  • RBH

    Jim Stewart the risk is real my huband died in the cab of his truck . Had OSHA been involved in this matter and Liberty Mutual not hounding the medical examiner to rush to a decision , I would not still be pursuing what happened to him. Cancelled Test and test finally performed six months after his death showed he still had carbon monoxide in his liver tissue. The blood samples were conveniently not usable. Its hard to get justice when you can’t afford an expert witness and the company is not really intersted in what happend to their driver.

  • pjh62

    I lived in Vancouver Canada and used to listen to KGO radio. Dr. Bill was forever talking about the dangers of MBNA. Well, once, a container of the stuff leaked into our harbour and my husband approached the news media about it and the lady stared at him like he was some kind of nut.

  • harold
  • harold

    Alot has changed, started in the late 70’s. These new emission engines are dangerous, look into I have been in emergency rooms, these trucks arnt built for the emission engine, go and put an air freshner under the hood, close the hood, sit in the truck with engine running, turn on fans heat or air cond. Wait about 5 mins, now if the aroma from the airfreshner comes at u, think about the toxens from that emission engine. Like I said go to

  • Juan Maldonado

    This problem is made worse in these newer trucks with all their emissions equipment. Exhaust leaks left and right after only a few thousand miles. Every joint or connection in the exhaust system is a potential source of dizzying fumes that manage to get into the cab and no way to really ventilate the cab properly and comfortably while driving down the road.

    I drove a 2013 prostar that had bad exhaust leaks and a volvo with a less complex exhaust system that was easier to repair once i identified some leaks. strives to maintain an open forum for reader opinions. Click here to read our comment policy.