That white stuff covering Judy Garland? Pure asbestos, of course—in chrysotile form, making the material a bit more dangerous than, say, in building material. (By the way, not exactly a nice gesture on the part of the Good Witch there, but odds are good she didn’t know about mesothelioma, because not a lot of people did.)

In defense of Metro-Goldwyn-Mayer and other users of asbestos snow in the 1930s, this stuff was common, and not only on film sets. It was not unheard of during this period to purchase Christmas supplies that included a form of fake snow made of asbestos.