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My bout w/ CO on the jobsite

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My bout w/ CO on the jobsite

My head hurts and I feel dizzy.” –That was my response to the job superintendent as he asked me about the water service line I was installing in a new warehouse building just four days ago.

If you had been standing there you can imagine his frustration as he was really asking a yes or no question. Just as my response was heard the rather grotesque sounds of two concrete workers vomiting nearby had each of us in a state of confusion and quickly in worry mode.  This was the direct result of carbon monoxide (CO) exposure and all three of us were in definite need of fresh air.


These were the cause of our problem situation.  The combination of gasoline engines (power trowel) running inside and the lack of enough combustion air and venting of the temporary heater made for potentially deadly mix.

Normally a heavy duty flexible duct is attached to the backside of the job heater that brings in air from the outside, this one had that but it was removed when the heater was moved to accommodate a delivery of materials and was never reattached. The weather here has turned cold and the concrete mix being poured was high in chloride for a fast set. There were three large overhead doors opened half-way as an attempt to vent the area; add the huge heater blasting mega Btu’s and everything should go as planned. But we already know things didn’t turn out that way.

I can’t say exactly why the area wasn’t getting the proper venting we needed, I can only guess that wind from the outside was effecting the plan to the end result of a few guys having been exposed for too long to high levels of carbon monoxide.

“Carbon monoxide (CO) is a poisonous, colorless, odorless, and tasteless gas. Although it has no detectable odor, CO is often mixed with other gases that do have an odor. So, you can inhale carbon monoxide right along with gases that you can smell and not even know that CO is present.” –OSHA

Information about CO is readily available from trusted sources such as the Occupational Safety & Health Administration (OSHA) online. The explanation is taken directly from an OSHA fact sheet you can download as a PDF.

This situation has reminded me of the importance of knowing and monitoring my surroundings while on the job. I can only speak for myself when I say that I tend to take for granted that I’m safe from things like this happening to me. I think a lot of assume that no one else wishes to find themselves in a dangerous situation so, they must be doing everything they can to work safely and in return we’re probably okay too. Seemingly that was the case in this situation but things didn’t exactly work out that way.

It took almost two full days for my headache to go away. I consulted with a close friend who is an emergency room doctor about my experience and symptoms. He gave me the go ahead to go about my business as usual with the warning that it could’ve been a lot worse and that there is little they can do to make things better. Time would have to run its course for me. I’m glad to say it has and I have been rid of all the symptoms/effects of the poisoning situation.

I started researching online the different types of Personal Safety Gas Monitors; there are a lot to choose from. Have you used one of these devices? Can give me a recommendation of a monitor you have used/liked? I’d appreciate any comments you have to add.


  1. Mark Eatherton
    Mark Eatherton11-26-2013

    Eric, I am glad you survived your brush with mortality. I’ve always told my wife, if I ever get a severe case of CO poisoning, please do not prolong the inevitable. Pull the plug. Although death by CO cuts life short, being a veg for the rest of your life and being dependent upon your loved ones sucks even more life out of people surrounding you. I have had numerous high level exposures to CO, some inadvertent, some (at least one) intentional.

    I think hte worst case was on a new job site, and the plumber was trying to get his final inspection so the owners could move in that weekend. The inspector called them out on the fact that they didn’t have the required catch pan below their water heater on a wooden floor. The GC was already using the DHW heater for cleanup, so instead of draining the tank and doing the right thing, he bear hugged the water heater and piced it up (FULL) a couple of inches and had his aprenti slide the pan under the heater, I continued working in the mechanical room commissioning a huge snowmelt system I was responsible for. When I started running pumps later that afternoon, I noticed a BUNCH of condensate on my uninsulated lines bringing extremely cold glycol back into the mechanical room, but blew it off to the cleaning chores going on inside the home. About 4 PM, as I was starting to shut things down, I noticed that the 4″ elbow serving the water heater that had been dead lifted earlier in the day had gotten its elbow on the vent broken,and all of the products of combustion were venting into the same room Id been working on all day. I shut the heater off, notified the GC, who contacted the Sheet metal guy, who replaced the elbow and fired it back up. I thought to myself, “Well, that explains the condensation on the pipes…” and went about closing down the job. I had one more emergency service call to do on my way back to town. I got in my vehicle, and headed off to town. I got completely back to Denver, and realized I hadn’t stopped at the appointed service call on my way back, turned around in my driveway, and drove all the way back to the service call, only to discover I hadn’t grabbed ANY of my tools. I left them in the driveway of the home with the snowmelt system. And I consider this a MINOR case of exposure. Shortly thereafter, I went to WW Graingers and purchased their Sentinel model (not even sure if its still available because this was 10 years ago). It was a single gas (CO only) model. I know they have multiple gas models available now, and they really aren’t all that expensive. I must warn you though, these things go off in the strangest places, like the aisles of Home Depot (LP burning fork lifts) and in front of gas logs in hotel lobbies (really?) but the strangest time was when I opened up a bag of roasted coffee beans. It went into HIGH exposure alarm condition immediately… CO is THE most common method of inadvertent poisoning, and it is also THE most preventable means of poisoning. I can’t tell you how many people had gotten sick on new construction job sites using atmospheric boilers that get clogged up with sheetrock dust and spill ALL of their products into the environment. Funny how everyone gets flue symptoms at the same time, and no one thinks about why. So much for roll out switch protection…

    Travel safe out there and have a Happy Thanksgiving and Hannuckah for my friends of a Jewish persuasion.

  2. Jim Godbout
    Jim Godbout12-05-2013

    Hi Eric
    Hope you guys are not freezing to death in Midwest
    I had experience with CO about ten years ago on job site barely made it out the door as I felt tightness in chest fell to the ground and neighbor called ambulance. Spent two days in hospital getting blood oxygen back on track.
    Since this time I have educated many of our contractors on safety of temp heating.
    Most have gone to very safe electric on long term heating or vented units we would install.
    Pretty scary feeling, glad it had some warnings before to late.
    You and john keep warm little early for sub zero temps

    Take care

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