I've seen operators driving forklifts ( smoking a cigerette) while the propane connector sprayed liquid propane like a fountain, I've seen propane companies refilling tanks on forklifts & in enclosed rooms. I even had 1 customer running his forklifts on medical grade propane ( no odorant ) inside their wharehouse which was attached to the front main office building (about 200 people worked under roof). Training & certifying people is great- getting them to follow procedure is quite another. Sometimes I wonder how more people don't die in & around forklifts.