I have been around very dangerous (highly combustible & explosive) substances for several projects I've worked on in the past, but I always knew where the limit was, and as a consequence have never been injured. Not even a scratch. I've also never damaged anything important either. I try to pass this message along to others as much as the knowledge of the substances themselves. From time to time it may sound as though I'm involved in something crazy (like bathroom flame-throwing), but I assess the risks very carefully. I've worked enough in thermochemistry over the years to have this risk assessment and safety factoring come as second nature.