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:
·
“T” type light
bulbs with a self-extinguishing feature that shuts off the light within 15 minutes after the outer bulb is broken.
“T” type light bulbs may be used in either open fixtures or enclosed fixtures. FDA requires packaging for “T” type
light bulbs to include the following statement:
“This
lamp should self-extinguish within 15 minutes after the outer envelope is broken or punctured. If such damage
occurs, TURN OFF AND REMOVE LAMP to avoid possible injury from hazardous shortwave ultraviolet
radiation.”
·
“R” type light
bulbs are not self-extinguishing. “R” type light bulbs should only be installed in light fixtures that are fully
enclosed by a lens of glass or plastic to shield people from the UV radiation, or in areas where people will not be
exposed to UV radiation if the outer bulb breaks. FDA requires packaging for “R” type light bulbs to include the
following statement:
"WARNING:
This lamp can cause serious skin burns and eye inflammation from shortwave ultraviolet radiation if outer
envelope of the lamp is broken or punctured. Do not use where people will remain more than a few minutes unless
adequate shielding or other safety precautions are used. Lamps that will automatically extinguish when the outer
envelope is broken are commercially available."
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:
·
Additional
information on care and maintenance of high intensity metal halide and mercury vapor lamps used in
schools: http://www.nema.org/stds/halide-schools.cfm#download, and
·
Best practices
for metal halide lighting systems: http://www.nema.org/stds/LSD25.cfm.
For more
information please visit the FDA's web site about
high intensity mercury vapor lighting.
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