You are the entry supervisor for entry into a Carbon Monoxide (CO) Tank. Your meter is equipped with an Oxygen Sensor, but it does NOT have a CO sensor. You proceed with your atmospheric testing, as you were told years ago that as long as the Oxygen was over 19.5% that all will be OK. What you do not know is that CO is a “magic asphyxiant”, technically called a “Chemical Asphyxiant” and regardless of how much O2 is present, you can still be entering an atmosphere where your body will NOT care how much O2 is available. Our entrants will suffer from a life-threatening situation called Oxygen Deprivation. Here is what happens: (Members can see more below the video)
Too many safety professionals (and I use that term loosely) do not understand the difference in Chemical Asphyxiants and Simple Asphyxiants. I hear it all the time in my PRCS training that “as long as there is at least 19.5% O2 in the space, there is no hazard of an oxygen deficient atm. Nothing could be more WRONG!!
You could have as much O2 as you want… our hemoglobin has an affinity for CO 300X’s more than for O2. So there is O2 in each breath we take, but it is the CO that gets into our bloodstream – hence we die from oxygen deprivation even though the O2 meter says we are in 20.8% O2!!!!
A MUST read for anyone wanting to learn more about the difference in asphyxiants: Asphyxiants: Simple and Chemical
chemical asphyxiant – An agent that prevents the delivery of oxygen from the bloodstream to cells, or that disables the biochemistry of cellular respiration even in the presence of adequate oxygen levels in the blood. Chemical asphyxiants include agents such as carbon monoxide and cyanide. Initial treatment consists of the administration of 100% inspired oxygen, usually by nonrebreather mask.
simple asphyxiant – A gas that displaces oxygen from the atmosphere, thereby reducing the amount of oxygen available during inhalation.
