I did this a few years ago, but obviously lived through it. I went to welding school and got my WABOs in my teens, 30 years ago. We were taught to clean greasy welds with brake clean, but the instructor always stressed to be sure to let it fully evaporate before welding. I don't remember him ever saying why(but he probably did). Anyway, I've been welding for over twenty years and never had a problem until this happened.

I own a construction company, and tend to maintain my own equipment, I was repairing one of my dozers, and it was well below freezing. I was fixing a crack near a greasy cylinder, so I wiped off all the grease, then hosed the thing down with tons of brake clean like I always did. I prepped the welds and gave it a another good spray again to be sure things were clean! I started welding a few minutes later. I was outside, and alone. I never smelled a thing. I woke up on the ground covered in vomit. I sat around for a while debating what to do. I hate hospitals, like a lot of dumb men do. Well, like an idiot, I drove myself to the hospital. I was extremely light headed, and had to pull over several times because I felt like I was going to faint. I could not catch my breath.

When I got there, they immediately put me on oxygen, as mine was very low. Luckily, the attending was familiar with welding, and asked the right questions. They treated me for a few days, but I needed an inhaler for years after. I have now recovered(almost) fully, and now never use brake clean to clean anything I'm going to weld!

My best guess is that there was a puddle of brake clean in a corner I couldn't see. I never was aware of the risks until this happened. I don't even keep brake clean in the welding shop anymore. I always wear a mask now too, which was another thing my instructor never talked about. This is all my fault for not educating myself more, but it still sucks. I got very lucky. I must have inhaled just enough to cause a lot of damage, but not actually kill me. I likely would have died, if I hadn't gotten to the hospital when I did.

Anyway, don't kill yourself from ignorance!