I quote from Bill Bryson’s At Home:
At times in the past attempts have been made to capitalize on bats’ special qualities. In the Second World War, the American military invested a great deal of time and money in an extraordinary plan to arm bats with tiny incendiary bombs and to release them in vast numbers ‚Äî as many as a million at a time ‚Äî from planes over Japan. The idea was that the bats would roost in eaves and roof spaces, and that soon afterward tiny detonators on timers would go off and they would burst into flames, causing hundreds of thousands of fires.
Creating sufficiently tiny bombs and timers required a great deal of experiment and ingenuity, but finally in the spring of 1943 work had progressed sufficiently that a trial was set to take place at Muroc Lake, California. It would be putting it mildly to say that matters didn’t go quite to plan. Remarkably for an experiment, the bats were fully armed with live bomblets when released. This proved not to be a good idea. The bats failed to light on any of the designated targets, but did destroy all the hangars and most of the storage buildings at the Muroc Lake airport, as well as an army general’s car. The general’s report on the day’s events must have made interesting reading. In any case, the program was canceled soon afterward.
Another chapter tells us
More people die of food poisoning at church picnics annually than have died in all history from contact with bats.