Brake Cleaner is "Not the best" for you, regardless of which state it is in, the interesting part, is how come it didn't evaporate before he got to that spot.
I've used brake clean before, and welded over it when it was nearly evaporated, stinks.
Paints, Primer, lacquer coatings on pipe, they all stink and are not good for the body.
Ironically I love the smell of 6010.
Phosgene gas can come from nearly any weld, it is present in nearly all welding fumes. Especially TIG, UV rays react with (I think its O2) and it combines with something else in the air and turns into phosgene. Tig so happens to have the highest output of UV.
I think this might require some further research.
Aha!http://en.wikipedia.org/wiki/Phosgene"Upon ultraviolet radiation in the presence of oxygen, chloroform slowly converts into phosgene via a radical reaction. To suppress this photodegradation, chloroform is often stored in brown-tinted glass containers. Chlorinated compounds used to remove oils from metals may also react under the UV created during arc welding to produce phosgene."http://cbwinfo.com/Chemical/Pulmonary/CG.shtml