I don't mean to be pedantic, but I wonder how one would qualify it as the "World's Most Dangerous Toy."
Plastic bags and pools are quite dangerous to unattended children. Yet, how could quantify the dangerousness of different toys? Hours of play per injury? How many hours of play would it take before the probability of injury or death approached 1? You'd probably also have to consider distribution of said toy.
Buckyballs became ubiquitous in offices, but how many children played with them - especially given the number of warnings the firm gave before they went out of business. I'm guessing that five minutes of play with a one year old will likely result in swallowing a buckyball. Also, if you google for "most dangerous toy," you'll find a spy kit with asbestos in the finger printing powder. How dangerous is that per minute of play? My guess both buckyballs and the asbestos kit are way more harmful than any low-level radiation from this toy, which would take several days to years to cause harm.
It would probably be a horrible statistic to actually calculate, but I wonder what the real most dangerous toy is.