and Margaret Hamilton was alergic to explosions...
So many interesting stories developed behind the scenes of that movie...like the time Margaret Hamilton, as the Wicked Witch, nearly got "all blowed up" when her smoking broom exploded. She got some nasty burns, and the makeup artist insisted on removing Hamilton's green makeup before the medical people arrived...she recalled the searing pain** when makeup remover was applied to her burned skin...makes my skin crawl just thinking about it.
** In Harmetz's The Making of the Wizard of Oz...a great read if you're into the history of Hollywood's Golden Age