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Ultraviolet Radiation Burns from High Intensity Metal Halide and Mercury Vapor Lighting Remain a Public Health Concern
Notice to Schools and Other Indoor, All-Purpose Facilities Where
Light Bulbs are Subject to Damage
Broken and unshielded high intensity metal halide and mercury
vapor light bulbs continue to cause eye and skin injuries, particularly in school
gymnasiums. To prevent these incidents from recurring, FDA recommends the following
in schools and other indoor, all-purpose facilities where the light bulbs may
be broken:
- replacement of open or wire grid fixtures with enclosed fixtures,
or
- replacement of non-self extinguishing “R” type
high intensity metal halide and mercury vapor light bulbs used in open or
wire grid fixtures with self-extinguishing “T” type light bulbs.
The 2005 National Electrical Code addresses high intensity metal
halide and mercury vapor light bulbs installed in newly constructed or renovated
indoor sports or all-purpose facilities. Because the bulbs in such areas are
subject to physical damage, they must be installed in fixtures that are fully
enclosed by a lens of glass or plastic to protect the bulb from breakage.
The best way to reduce the risk of burns is to use fully-enclosed
fixtures or self-extinguishing “T” type mercury vapor light bulbs
in facilities where the public can be exposed to the ultraviolet (UV) radiation
from a broken bulb.
Background
The Food and Drug Administration (FDA) recently learned that more
than 100 people were exposed to short-wave UV radiation from a broken mercury
vapor light bulb at a high school gym. Eighteen people went to the hospital
with severe eye and skin burns. Personnel investigating the event confirmed
that a broken, non self-extinguishing "R" type metal halide bulb caused
the injuries.
Similar incidents have been reported in the past involving “R”
type light bulbs installed in open and wire grid fixtures. Most injuries have
occurred inside school gyms, after the light bulbs were struck and partially
broken by balls or other sports equipment. FDA is not aware of any incidents
involving “T” type light bulbs, or involving light bulbs installed
in fixtures fully enclosed by glass or plastic.
What are Halide and Mercury Vapor Light Bulbs?
Metal halide and mercury vapor bulbs are bright, long-lasting
sources of light, most often used to light streets, gyms, sports arenas, banks,
and stores. The bulbs have an inner quartz tube, containing the mercury vapor
discharge, enclosed by an outer glass bulb that filters out harmful short-wavelength
UV radiation. If the outer bulb breaks and the inner tube continues to operate
unshielded, intense UV radiation is emitted. UV exposure at this level can cause
eye and skin burns, as well as blurred or double vision, headaches, and nausea.
Types of halide and mercury vapor light bulbs sold in the U.S.
include:
Precautions for Facilities that Use Metal Halide and Mercury
Vapor Lighting
All schools and other indoor, all-purpose facilities using metal
halide and mercury vapor lighting should inspect both the light bulb and the
fixture on a regular basis to ensure that they are not broken. With
the light fixture turned off,
- Check the light fixture. Replace any fixture that is damaged.
Damaged, open fixtures, or fixtures with wire guards DO NOT protect the bulb
from breakage and will not protect the public from UV radiation.
- Check the bulbs. Replace any light bulbs that are missing,
broken, or punctured.
- Ensure light bulbs are installed in appropriate fixtures. Self-extinguishing
“T” type light bulbs should be installed in open fixtures or fixtures
with wire guards. Non self-extinguishing “R” type light bulbs
should only be installed in light fixtures that fully enclose the light bulb
and have a lens of glass or plastic to protect the light bulb from breakage
and protect the public from UV radiation.
- School supervisors should make sure that those responsible
for the maintenance of these lighting systems fully understand the manufacturer’s
warnings on product packaging, as well as Federal, State, and local guidelines
to reduce the risks associated with these products.
If a metal halide or mercury vapor light bulb is broken during
use,
- TURN OFF THE LIGHT IMMEDIATELY.
- Move people out of the area as quickly as possible.
- Advise people exposed to the damaged bulb to see a doctor
if symptoms of skin burns or eye irritation occur.
- Report injuries from damaged light bulbs to the bulb
manufacturer, your state health department, and the nearest FDA district office.
- Check to make sure the light fixture is turned off before
replacing the damaged light bulb. It is important to retain the broken bulb
to identify the bulb type and manufacturer, and to assist with any investigation
conducted after the incident.
The National Electrical Manufacturer’s Association (NEMA)
web site contains:
For more information on FDA’s web site about high intensity
mercury vapor lighting, see http://www.fda.gov/cdrh/radhealth/products/mercury-vapor.html
Updated December 29, 2006 |