I had a Milwaukee M18 8.0 battery go up in flames just 5 feet from me. A palm nailer of mine shot a nail into the side of the battery and it went UP in a multi-colored blaze of glory. Smoke, sparks, blue, red, orange and green. As soon as it started, I held my breath and got the heck away from it. It burned for 30 seconds but was out before I could grab the extinguisher.