EXPLODING FLASHLIGHTS:
ARE THEY A SERIOUS THREAT TO WORKER SAFETY?
Is it true that
flashlights can, and have, exploded while in use by workers? |
Yes. The National Institute for Occupational Safety
and Health (NIOSH) has received reports of incidents
where flashlights have exploded while in use by fire
fighters. In December 1992, a flashlight used in a
fire fighter training exercise exploded, slightly
injuring one fire fighter. In January 1995, a
flashlight carried in a fire fighters pocket
exploded, although he was not injured. Previous reports
of exploding flashlights have appeared in the public
safety literature. |
What causes
flashlights to explode?* |
In the types of batteries most commonly used in
flashlightszinc/carbon batteries and alkaline
batterieshydrogen gas (H2)
is produced naturally as a product 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. Excess hydrogen
gas is more likely to be released if batteries are used
incorrectly; that is, if different types or brands of
batteries are mixed, damaged batteries are used, old
batteries are mixed with new batteries, or batteries are
inserted incorrectly so that polarity is reversed.
Excess hydrogen gas may also be produced by rechargeable
batteries during recharging. If H2
accumulates within batteries or battery compartments
without sufficient release, the buildup of pressure can
cause the battery or compartment casing to rupture. Also
H2 and oxygen (O2) mixtures are highly
explosive, and if ignited by a spark or excessive heat
can produce powerful explosions. |
Can the
accumulation of H2 be prevented? |
Many batteries or battery compartments are constructed to allow leakage and dissipation of H2. However, some battery compartments may be sealed tight against air and water by design. Some flashlights are constructed this way to enable their use by underwater divers and others who must have air- and water-tight equipment. Some manufacturers of equipment with air- and water-tight battery compartments have incorporated safeguards to prevent H2 accumulation. For example, one-way relief valves may be incorporated in battery compartments to allow H2 to escape. Or, chemicals may be used to absorb or recombine H2. However, even these safeguards may not be sufficient if batteries are used incorrectly and excessive levels of H2 are produced. |
Is there one
particular brand, model, or type of flashlight that is more likely to explode? |
NIOSH does not have sufficient information to
determine whether the risks are higher with specific
brands, models, or types of flashlights, than with
others. However, the 1992 and 1995 explosions cited
in this fact sheet involved one particular brand and
model of flashlight: the Super SabreLite Submersible,
Model 2000 series flashlight, manufactured by Pelican
Products, Inc. (2255 Jefferson St., Torrance, CA
90501). This flashlight features an air- and water-tight battery compartment, and is used by underwater divers, military personnel, fire fighters, hazardous materials workers, emergency response workers, and other public safety workers. The Model 2000C incorporates both a pressure relief valve, and a chemical catalyst to recombine H2. These precautions did not prevent the January 1995 explosion, which involved a Model 2000C. An examination by the Mine Safety and Health Administration (MSHA) found that use of different brands of batteries, with presumably different charge states, contributed to the 1995 explosion by causing the release of hydrogen gas at a rate that exceeded the venting capacity of the pressure relief valve. |
How serious
is this hazard? |
Any explosion creates the potential for injury due to
the force exerted by the explosion itself, the potential
that materials such as equipment components or pieces
will fly outward from the source of the explosion with
sufficient force to strike and injure someone, and the
possibility that caustic or toxic substances could be
released and come into contact with someone. In addition
to the potential for injury, an exploding flashlight
could touch off a larger explosion in a flammable
atmosphere. The Super SabreLite Submersible Model
2000C is currently approved for use in flammable
atmospheres by the Mine Safety and Health Administration
(MSHA), the Factory Mutual Research Corporation (FM), and
the Canadian Standards Association (CSA). |
How can
workers who use battery-powered flashlights protect themselves? |
In order to protect themselves, workers should follow
these precautions:
|
Are
flashlights the only type of battery-powered equipment that can explode? |
No. The potential for explosion may exist in
battery-powered equipment other than flashlights. The
accumulation of hydrogen gas within batteries or battery
compartments may result in explosion of batteries
themselves, or the explosion of the equipment in which
they are housed. Due to the widespread use of
battery-powered equipment in numerous occupational
settings, NIOSH urges all employers and employees who use
battery-powered equipment (including those with
rechargeable batteries) to be aware of the potential
explosion hazard described in this Fact Sheet. |
Where can I get
more information about this and other workplace hazards? |
For more information about the hydrogen gas explosion
hazard associated with batteries and battery-powered
equipment, see Levy SC, Bro P. [1994] Battery Hazards and
Accident Prevention. New York: Plenum Press. To
obtain information about workplace hazards, contact the
NIOSH toll-free number or website at the address shown
below. |
To order copies of NIOSH documents or to receive more information about other occupational safety and health problems, call 1-800-356-4674. Visit the NIOSH Home Page on the World Wide Web at http://www.cdc.gov/niosh/homepage.html. NIOSH appreciates the assistance and cooperation of the Mine Safety and Health Administration (MSHA), the Occupational Safety and Health Administration (OSHA), the Consumer Product Safety Commission (CPSC), the International Association of Fire Fighters (IAFF), and Pelican Products, Inc., in the development of this fact sheet. This document may be freely copied or reprinted. |
*Levy SC, Bro P [1994]. Battery
Hazards and Accident Prevention. New York: Plenum
Press. 351 pp.
U.S. DEPARTMENT OF HEALTH &
HUMAN SERVICES Public Health Service Centers for Disease
Control and Prevention National Institute for
Occupational Safety and Health |
June 1997 | DHHS (NIOSH) Publication No. 97-149 |
Return to Fire Fighter Homepage
This page was last updated on 10/04/06