In the early days of celluloid production, the factories were built in such a way that the roof structure was hinged to the rest of the building. This stuff was soooo explosive. They knew that it was only a matter of time before the stuff would blow. With the roof on hinges, the force would blow the roof and not damage the rest of the factory quite as much. Needless to say, insurance became scarce for a lot of these manufacturers and many went out of business.
And people complain about their jobs today?
Greg