How do you lose an ICBM?

Ukraine has apparantly lost several hundred ICBMs. They decommisioned them during the 90's after independence, but have no record of them actually being destroyed. Poor record-keeping is the most likely explanation, but you still have to worry. For some reason I'm thinking of the Second-Amendment fundamentalist in Iain Banks' The Business who thought that his "right to bear arms" extended to a couple of Scuds concealed in grain silos..