Algorithm if DOT comes into your shop somebuddy has really messed up. DOT is American and the inspector would be really lost if he showed up in your Toronto shop! TC=Transport Canada can inspect the cylinders, the valves are TSSA's and air bounces back as Dundas mentioned to buyer beware or hope that the MOL is protecting the workers in the shop. Mind you the Ontario laws still refer to the 85 standard which would allow Dundas with his hand held Drager or MSA unit to go make so extra coin on the side. Scarry isn't it. You think they would at least ask you to meet the 2000 standard which requires the accredited lab.
I saw the results of a LDS from a buddy of mine and it had a little bit more than excessive CO. Well after seeing the results I decided I could get air elsewhere or just stop taking my-multi vitamins as I was getting all the minerals etc I need from the air. Bromine, Toulene, Berilium, Tungsten, Sulfer, Methyl-Ethyl bad stuff etc.......That was from a PADI 5 star facility. Its been a long time since I took chemistry in high school but I thought that North American Oil was high in sulfer--could it be?? Do those hand held units check for 10-W-30?