Star Targets are very safe when used as intended and the directions are followed. Once mixed it must be impacted with a high velocity round to set it off, it will not go off if it dropped, shaken, kicked, even lit on fire. You can hit it with a hammer, shoot it with a pistol, or throw it off your roof. It takes about a 40 grain bullet traveling at 2200 FPS directly impacting it to cause it to go off, anything below these requirements will not set it off.