This is why you don’t leave your container of black powder out on the bench when your shooting. It just takes a single spark and things get ugly. If your lucky you just lose your eye brows, if your not you maybe start a fire or start cooking off other nearby ammo.
In any case, be careful, think before you shoot and always wear protective glasses when shooting – which this guy wasn’t. Hopefully he didn’t burn his eyes or get black powder dust in them.