That's a interesting question that is not as easy to answer as you might think. There's two figures used to describe the weight of product in a fireworks display - one is the gross weight which includes all the paper, clay, card and other packaging that goes into fireworks such as shells and Roman candles. This figure is always the larger of the two - often by a factor of 3 or more, depending on the type of fireworks. The media almost always uses this figure because it sounds more impressive: "The fireworks display used 5 tonnes of explosives!" they
will say. The other, more accurate figure, is the "Net Explosive Quantity" - abbreviated as NEQ. This is the actual weight of the black powder and other compositions used. An item like a cake will have a relatively small NEQ compared to it's gross weight whereas as 12" shell with have and NEQ that is close to its gross weight.
When I interviewed Paul Csukassy in 1999, he told me the organizers pay for the transportation of up to 750kg NEQ. I'm not sure what the figure is now, nor what is actually used in a typical display. But at least that should give you a good ball-park figure. A display with an NEQ of 750kg may well have a gross weight of around 5 tonnes.
Paul. | 
