j_martin

Not only is phosgene very poisonous, it is also extremely corrosive. Worst case I saw was when I moved a computer shop into a space that had last been used by a custom RV outfit. Winter came and the furnace kicked in. Our eyes watered and we bailed, CO through the roof.

Turned out that the RV outfit stored their refrigeration cart in the furnace room. There was nothing left of the heat exchanger.

Yeah, welding and chlorinated brake cleaner are inimical to lung function.

MrFusion

One "fix" I've heard about is using an oxy fuel torch to burn off the Brakleen residue before welding. I've done this on the very rare occasions that I've used brake cleaner to clean something I was going to weld (since I found out about the phosgene danger). Maybe you HVAC guys can tell me if this is right or if I've just been lucky.

Jim Lane

I think you have just been lucky 😵

Welding can produce nasty toxic vapors especially in confined spaces,

I did some stick welding on some galvanized pipes one time and even though I had forced air purging my helmet I got a whiff of the smoke and I really got sick, headaches and I was seeing weird bright colors for some time, I was sure I had metal fume fever.
Jim