This is an amazing summary from OSHA that shows us the number and severity of Hot Work Accidents involved with doing hot work on improperly prepared vessels. There are other hot work fatalities mixed in, but the vast majority of these incidents involved welding/cutting on vessels/containers that were NOT properly prepared. Check out 1910.252(a)(2)(vi)(C) and 1910.252(a)(3)(i) for some critical requirements when welding on containers/vessels.