Shock sensitivity is a comparative measure of the sensitivity to sudden compression (by impact or blast) of anexplosivechemical compound. Determination of the shock sensitivity of a material intended for practical use is one important aspect ofsafety testing of explosives. A variety of tests and indices are in use, of which one of the more common is the Rotter Impact Test with results expressed as FoI (Figure of Insensitivity.) At least four other impact tests are in common use, while various "gap tests" are used to measure sensitivity to blast shock.

A few materials such asnitrogen triiodide cannot be touched at all withoutdetonating, and so are of purely academic interest. Some other compounds with a high sensitivity to shock, such asnitroglycerin andacetone peroxide, may detonate from a firm jolt and so cannot be legally transported in pure form. Acetone peroxide is often used by amateurs and terrorists as a means to detonate other explosives as well as acting as the main blasting agent, often resulting in injuries or death to those who underestimate its sensitivity. A number of methods are known to desensitize nitroglycerine so that it can be transported formedical uses, and it is also incorporated into other less sensitive explosives, such asdynamites andgelignites.

Many practical commercial materials of intermediate sensitivity, such as gelignites andwater gel explosives, can be safely handled as they will not explode from casual shocks such as being dropped or lightly knocked by a tool. However, they may explode if struck forcefully by a metal tool, and would certainly explode in the barrel if they were used in an artilleryshell. Reliable initiation of such materials requires the small explosion of adetonator. Apart from this another explosive material such asArmstrong's mixture is also used in commercial markets and even sold to the public in the form offireworks,cap guns andparty poppers.

Still less sensitive materials such asblasting agents likeANFO, are so insensitive that the impulse from the detonator must be amplified by anexplosive booster charge to secure reliable detonation. Somepolymer bonded explosives — especially those based onTATB — are designed for use ininsensitive munitions, which are unlikely to detonate even if struck by another explosive weapon.