Most
people know that radioactive energy can be harnessed to provide
electricity and even to diagnose and treat certain illnesses. But would
it surprise you to learn that radioactive materials also perform an
important safety function by lighting emergency EXIT signs?
Look
for the EXIT sign the next time you go to work, school, a sporting
event, religious service, the movies, or the mall. If the sign glows
green or red, chances are it contains a radioactive gas called tritium.
The
tritium,
a radioactive isotope of hydrogen, is sealed into glass tubes lined
with a chemical that glows in the dark. Tritium emits low-energy
radiation that cannot penetrate paper or clothing and even if inhaled,
it leaves the body relatively quickly. As long as the tubes remain
sealed, the signs pose no health, safety, or security hazard.
NRC
estimates there are more than 2 million of these signs in use in the
United States. To ensure safety in handling and the manufacturing
process, NRC and its
Agreement State partners
regulate the manufacture and distribution of tritium EXIT signs.
Companies have to apply for and receive a license before they can
manufacture or distribute one of these signs.
But
because the signs are designed to be inherently safe, NRC does not
require any special training before a building can display the signs.
Users are responsible for meeting the requirements for handling and
disposal of unwanted or damaged signs and for reporting any changes
affecting the signs.
Proper
handling and disposal is the most important safety requirement for
these signs. A damaged sign could contaminate the immediate area and
require an expensive cleanup. That is why broken or unwanted signs must
be return to a licensed manufacturer, distributer, radioactive waste
broker or radioactive waste disposal facility.
Tritium
EXIT signs are one of several types of radioactive consumer products
that NRC allows. These products can be produced and sold ONLY if they
have a benefit that outweighs any radiation risk. See our earlier
blog post for more information on how we regulate these products.
Maureen Conley
Public Affairs Officer
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