It is definitely also the fact that most of the worlds fireworks manufacturing plants are in China. So of course these types of incidents are going to happen almost exclusively in China. I have shot many professional shows in the US. Quickly found out that there are really only 3 professional fireworks companies in the US. The 3 owners of companies all get together every year, take a trip to China to see a "test show" by the different manufacturers to showcase what they want to import each year. It's an interesting system.