I guess I was referring to what the orignal poster wanted, i.e., an explosion caused by a chemical reaction. Those are generally more dangerous than physical explosions created by overpressure. It is true, though, that even popping of a paper bag or a balloon could have problems, though they are minimal. Some explosions and some explosives are 'safe'. I would argue, though, that explosives are safe like sex is safe: there's still always a chance that something could go drastically wrong. Now, are the risks worth the reward? In many cases, yes. Is creating a bomb in the manner Goebbels suggested safe enough to justify the 'reward' of blowing up a small gelatin capsule in the lab? I would think not.