I used to drink from 1gallon glass jugs in Hawaii till my Mexican coworker asked me to be more careful. He explained that many a fire has been started by field hands toting water under the hot sun and leaving the jugs about whilst working. It's a very real thing.I know of a house fire started by the owner storing water in gallon glass jars on a window enclosed back porch. Total loss of the home.
Also have a friend who was very lucky to be home and discover early enough that the reflection from a magnifying mirror on the counter in a bathroom, next to a window on a sunny day, had ignited a towel hanging on a wall rod a few feet away. This was just a couple of months ago.