A sympathetic detonation is caused by a shock wave, or impact of primary or secondary blast fragments.
Special containers attenuating the shock wave can be used to prevent the sympathetic detonations; epoxy-bonded pumice liners were successfully tested.
[2] Blow-off panels may be used in structures, e.g. tank ammunition compartments, to channel the explosion overpressure in a desired direction to prevent a catastrophic failure.
Other factors causing unintended detonations are e.g. flame spread, heat radiation, and impact of fragmentation.
A related term is cooking off, setting off an explosive by subjecting it to sustained heat of e.g. a fire or a hot gun barrel.
Conversely, class 1.3 fuels can be ignited by a nearby fire or explosion, but are generally not susceptible to sympathetic detonation.
Class 1.1 fuels, however, tend to have slightly higher specific impulses, and therefore are used in those military applications where weight and/or size is at a premium, e.g. on ballistic and cruise missile submarines.
During the Attack of Pearl Harbor, the USS Arizona was struck with an armor-piercing bomb which penetrated the upper deck and stopped inside the forward magazine.
Multiple incidents have been recorded in the more recent GWoT where airstrikes have set off explosives or ammunition caches in insurgent positions.
A transient pressure wave from a nearby detonation may compress the explosive sufficiently to make its initiation fail.