I almost coughed a lung out after welding in my garage. I had prepped some aluminum with brake cleaner, and ate supper. I went back later to do the welding, and the vapors in the air burnt in the arc. The garage was closed the whole time because it was winter, but the doors don't seal well. Still, the brake cleaner hung in the air and taught me a lesson. I swear I thought I was going to cough myself to death.