I just came upon this and wanted to pass it on. This guy used common brake cleaner to prep an area for welding (MIG w/ gas) and almost killed himself because of the fumes created when he hit a tiny puddle of brake cleaner while welding. I know there's a few different kinds of brake cleaner out there but just be aware this danger is out there. Here's the full story from the horse's mouth:
http://www.brewracingframes.com/87c8ee40.jpg
http://www.brewracingframes.com/87c8ee40.jpg