Fire Extinguishers

in this link, I was reading the last paragraph and collided with this :
“Some of the Gases Detected by some of the above detectors include
Ammonia gas , Carbon Dioxide , Carbon Monoxide , Chlorine Dioxide , Chlorine , Combustible gas detection, Fluoride , Fluorine Hydrogen , Hydrogen Chloride , Hydrogen Cyanide , Methane , Nitrogen Dioxide , Oxygen detetector, Phosphine , Sulfur Dioxide , carbon monoxide, helium, hydrocarbon, hydrogen gas , methane , msa gas ,monoxide, propane , radon gas. ”

there it says. “, msa gas,”

I’ve searched ‘msa gas’ and only found a company that makes masks and detectors, but nothing about a “msa gas”

does it ring any bell to somebody?
oops, i put ‘knows’, It should have been ‘know’, sorry
ah, ok, I supposed that, somehow, but ’surely’ , I was not sure, he he

thanks for your time folks