Received the following information in a safety newsletter today and thought I'd share it with everyone...

The National Institute for Occupational Safety and Health (NIOSH)
has received reports of flashlights exploding while in use by
firefighters. These reports should remind anyone who uses
flashlights of the need for awareness and caution. The force of an
explosion alone can cause injuries, and if propelled by sufficient
force, so can parts or pieces flying out from the source of the
explosion. The source of danger in flashlight is the batteries.
Zinc/carbon batteries and alkaline batteries are the types most
commonly used. In both, hydrogen gas (H2) is produced naturally as
a result of the corrosion of the zinc electrode in the aqueous
electrolyte. Differences in batteries, including cell design and
charge rate, affect the rate and volume of H2 generation. If H2
accumulates within batteries or battery compartments without
sufficient release, the buildup of pressure can cause the battery
compartment casing to rupture. Most battery compartments are
designed to allow leakage and dissipation of H2. Some battery
compartments may be sealed tight against air and water by design,
but even these have safeguards to prevent H2 accumulation. So if
flashlights are designed with these safeguards, why are they
exploding in the hands of firefighters? No design is infallible,
especially under the pressure of heat and hard use common in fire
fighting. To avoid the danger of flashlight explosions, anyone who
uses a flashlight should take the following precautions:
Read the manufacturer's recommendations for use of the
flashlight and follow directions.
Don't mix different brands of batteries.
Don't mix old and new batteries.
Don't mix alkaline and nonalkaline batteries.
Don't use damaged batteries.
Be sure to install batteries with positive (+) and negative
(-) poles aligned correctly.
Before using flashlights in flammable atmospheres, make sure
the flashlight is approved for such use and that the batteries
are the correct type, in good condition and installed
NEVER open and inspect any flashlight in a hazardous area or
near an open flame.
For more information about the hazard of hydrogen gas explosion
associated with batteries and battery-powered equipment, call NIOSH
at1-800-356-4674 or visit their Web site at: NIOSH