Welding WARNING, PLEASE READ if you weld at all Options

[scotty b]

No matter how much you know you never know it all. Very important read, takes a few minutes to load so be patient

http://www.brewracingframes.com/id75.htm

[Madswede]

Yeah, I'm not sure I'd go so far as to call the story in the link total BS, but some things about the story seem ... embellished, I'll just say.

I mean, the story is accurate from several technical details (color of the cloud, chlorinated solvent exposed to high temperature presumably pyrolysis of the compounds resulting in some phosgene, delayed symptoms up to 48 hrs) ... but the symptoms seem a bit off to me, as others have said. In my experience as an accident analyst for a chemical weapons depot, phosgene is pretty nasty stuff but not usually fatal unless someone is very susceptible / sensitive. Typically, it will ultimately cause death (in high levels of exposure) via pulmonary edema and/or heart failure, not kidney failure. But that's just what I'd learned, and that was a while ago since I worked in the CW field.

Here's a link to what the CDC says about phosgene, in case people are interested.

http://www.bt.cdc.gov/agent/phosgene/basics/facts.asp

I'd be cautious about welding anything that may contain chlorinated hydrocarbons (such as piping that may contain or has contained refrigerants, which are typically chlorinated hydrocarbons), but that can easily be remedied by flushing the system properly prior to welding on it. Similarly, by allowing cleaners and solvents that may have chlorinated hydrocarbons to evaporate thoroughly prior to welding/heating up the parts cleaned with 'em, I would think that is a simple and smart thing to do.

Luckily for me, I don't weld. (IMG:style_emoticons/default/rolleyes.gif)

- Nelson