I was replacing a coil in the attic of a 1.4 million dollar house when I had a little accident... I pumped all the refrigerant back to the compressor and made sure there was no pressure in the lines, then I attempted to sweat the connections off the coil. The liquid line popped off with no issue as its done 1000 times before, the suction line on the other hand turned into a flame thrower... It shot fire out about 3' into this attic and did not stop for about 10 seconds. I was freaking out trying to put this bitch out. I got the flame to stop coming out of the line and then used the extinguisher to put out the oil fire that developed on the platform. I'm not sure why this happened, I have sweat off fittings after pumping down and making sure its at 0 psi many times before and at most I got a little poof. Needless to say I learned a valuable lesson, always cut lines on an existing system. So while I was frantically trying to put this fire out I took about 5 breaths of the burnt 410a fumes, this stuff is nasty... I am wondering if youguys know how toxic burnt 410a is? About 12 hrs later I went into some sort of allergic fit, I sneezed about 100 times in a 5 min period then my eyes became swollen shut. It took about 12 hrs for the swelling to go away completely. I cant be sure that the two incidents are related but I'm inclined to think so.