Eight American soldiers from the 10th Mountain division were killed when they were investigating an arms cache. There are hundreds, if not thousands, of arms and ammo caches in Afghanistan, many of them booby trapped by their owners to discourage thieves. Many of these caches date from the 1980s, placed their by Afghans fighting the Russians. Some of the people who placed this stuff in caves, the favorite hiding place, were later killed and knowledge of the location lost. But the caches are rediscovered as other Afghans  look for caves to stash stuff. The ammo, and especially explosives (often extracted from dud shells) dating from the 1980s, does not age well and spontaneous explosions will happen when this stuff is disturbed.