Can a 9V Battery Burn Down Your Home?

9V batteries are quite common in the U.S. and are often used in smoke detectors, amongst other things. They're quite reliable, lasting for a long time and are easy to use. There's only one problem – they're not as safe as you might think. When they come in contact with other bits of metal or other batteries, they can short out, causing sparks that may even cause the battery to catch fire.