i didn't read the article and you don't need a PhD to understand the dangers associated with chlorinated hydrocarbons. do a little more research, you don't need UV light (which welding produces). TCE/PCE and i'm sure others thermally decompose into Phosgene (and other nasty stuff). there are many others i'm aware of that will as well including dichlorodifluoromethane (R12). anyone that's used one of the old flame type refrigerant type leak detectors can attest to that. thermal decomposition of these chemicals can/will also release HCL. i used brake clean (VERY small amount) in a one car garage with a kerosene heater and got to enjoy the results. believe me you get a snootful of this stuff and you will understand.

i've warned of this numerous times here before...the threat is real, the welder is correct.