I think OP was referring to "fireworks stored next to ammonium nitrate." Fireworks are stupidly hazardous and should never be stored around high explosives. If

I think OP was referring to "fireworks stored next to ammonium nitrate." Fireworks are stupidly hazardous and should never be stored around high explosives. If the sparks had hit only the ammonium nitrate (because the fireworks had been properly disposed of or at least stored in a reasonable configuration), there's a good chance the fire would not have started.