One of the most dangerous tools has to be one of my Cousins. Picture this, here is a certified welder, many,many years on the job. Travelled all over the Midwest doing welding jobs. One day he asks my brother to help him on some kind of exterior house remodeling project. My brother, who was at the time a framing carpenter, thought nothing about why you use air instead of oxygen to power your air nailer. Long story short, spark ignited oxygen, blown up air nailer, short fall off of scaffolding, no broken bones but some stitches on neck & hands & a profound need for new undergarments!! My brother is just fine, BTW. He now does interior trim, cabinets, etc., for a builder out of Omaha. THEY USE AIR!!