In the 1960s I worked in the Special Collections section of Butler Library while going to school at Columbia. We received a gift of many films reels from the estate of Robert Flaherty (Nanook of the North, etc.). We had them stored on the upper floors of Butler Library in Special Collections. These were the days of using limited, 1930s-era, ammonia-based air conditioning in the library stacks. The upper floors got warm in a New York July.

As it turned out, the films were made of a silver nitrate base which, with heat and time, can turn into nitroglycerine. After inspection one July morning by the NYC Fire Marshall, the NYPD Bomb Squad was called, the building evacuated for several hours and the films removed, and in a bomb disposal truck and carried to a remote location (read Flushing Meadows) where as I recall they were blown up.