In small ammunition houses mostly explosives and detonators were stored in the middle of the forest for prepared bridges and street blasting. These houses were not guarded and provided with very elaborate door closures. However, it would have been a pretty hopeless attempt to break in here. Although the bunkers were not alarm-secured, the four consecutive doors alone would have thwarted such an attempt.
The first was a lattice door with thumb-thick bars, the second a 15cm thick reinforced door with special lock and the third a thick sheet steel door (gas pressure door). If the quantity of explosives to be stored exceeded 5 tons, another armored door was added inside. (The closed doors seen today did not meet the general standard). A detailed instruction for opening contained the "Obstacle Folder", the lock book. At these 3 or 4 doors, a potential burglar would have had some days to do, and there were certainly far easier ways to get explosives. The population were not aware of these deposits and a hiker could also think of the little unassuming houses as a water house. The little houses and the prepared barriers were filled and maintained by the wallmasters, who were mostly traveling with civilian vehicles. In the case of defense, pioneer soldiers would have picked up and deployed the explosives there.