Morning Gents. I am not rely a collector of larger munitions so perhaps some one can answer the following. How long can a 1Kg German Incendiary bomb remain dangerous after a long period of emersion in fresh water. The reason I am asking is that I was working with a local builder in about 1965 pulling down a filling station, we were dropping some steel I beams from the front of the workshop and found an Incendiary bomb lodged between two of the beams. The contractor was on tie schedule and rather than call the police and have the bomb dealt with he threw the bomb into a nearby canal. I would have thought that the impact of the bomb would have been sufficient to detonate the device, it had punched through the top web of a steel beam and lodged between them.