This fact sheet detailed the possible explosion hazard associated with flashlights. Firefighters had flashlights explode in two incidents. Batteries commonly used in flashlights produce hydrogen gas. The buildup of pressure within batteries or battery compartments can cause the battery or compartment casing to rupture. Hydrogen and oxygen mixtures are highly explosive and, if ignited by a spark or excessive heat, can produce powerful explosions. Some battery compartments are sealed tight against air and water by design, prohibiting built up hydrogen gas to escape. In addition to potential injury, an exploding flashlight could touch off a larger explosion in a flammable atmosphere. Workers should read and follow manufacturer's recommendations for product use, should not mix batteries of different brands, should not mix old and new batteries, should not mix alkaline with nonalkaline batteries, should not use damaged batteries, ensure that proper polarity is observed when installing the batteries, and inspect the flashlight batteries prior to use in flammable atmospheres. The potential for explosion exists in any battery operated equipment.