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Discarded Tritium Exit Signs
RadTown USA Topics
This page provides information on tritium exit signs, including proper handling and disposal methods.
On this page:
Overview
Exit signs are mounted in almost every building we go into, like high schools, grocery stores, movie theaters and shopping malls. Many exit signs contain tritium, the radioactive form of hydrogen. Mixing tritium with a chemical that emits light in the presence of radiation, known as "phosphor in a tube" (a sealed source), creates a continuous, self-powered light source. This useful property of tritium can be applied to situations where a dim light is needed but where using batteries or electricity is not possible.
Using tritium in exit signs ensures that the sign will remain illuminated in the event of an electrical outage or a fire. If the tubes in the exit signs are severely damaged, the tritium, which exists in the sign as a high temperature gas, might escape into the local area but most likely will quickly disperse in the air. Because a damaged exit sign will have relatively high levels of tritium in it, you should not handle it.
Remember
Do not handle damaged tritium signs.While damage to tritium exit signs is rare, it is most likely to occur when a sign is dropped during installation or smashed in the demolition of a building. If not damaged during demolition, tritium exit signs can be broken when they are illegally dumped in community landfills.
Tritium is naturally produced by the interaction of cosmic rays with the atmosphere. Tritium can also be produced by man-made processes, as is the case of tritium exit signs. Tritium decays by emitting a low-energy beta particle that cannot penetrate the outer layer of human skin. Therefore, the main hazard associated with tritium is internal exposure by inhalation. Internal contamination occurs when people swallow or breathe in radioactive materials, or when radioactive materials enter the body through an open wound or are absorbed through the skin. Some types of radioactive materials stay in the body and are deposited in different body organs. Other types are eliminated in blood, sweat, urine, and feces.
As with all ionizing radiation, exposure to tritium increases the risk of developing cancer. However, tritium exposure is likely to have a limited biological impact because it emits very weak radiation and leaves the body relatively quickly. In addition, because of tritium’s short half-life, tritium must be ingested in large amounts to pose a significant health risk.
Who is protecting you
U.S. Environmental Protection Agency(EPA)
Under the Clean Air Act, EPA establishes regulatory requirements for hazardous air pollutants including tritium air releases. Under the Safe Water Drinking Act, EPA sets limits for acceptable levels of tritium in drinking water. EPA also responds to emergencies involving tritium releases to the environment. In addition, before being approved for public use, sites previously contaminated with tritium must meet EPA's risk-based criteria for soil and ground water.
U.S. Department of Labor (DOL)
DOL's Occupational Safety and Health Administration issues regulations and standards for the safety of workers in a wide range of occupational settings including construction and demolition.
U.S. Nuclear Regulatory Commission(NRC)
The primary mission of NRC is to protect public health and safety and the environment from the effects of radiation from nuclear reactors, sealed sources containing radioactive materials, and radioactive waste facilities.
The States
Each state has one or more programs to address radiation protection issues and respond to and investigate incidents involving tritium.
Thirty-four states have signed formal agreements with NRC, providing the states regulatory responsibility over small quantities of special nuclear material and its source and byproducts. These states are known as NRC-Agreement States.
What you can do to protect yourself
Some basic precautions can minimize the risks. The tritium in exit signs can be identified by the tube (sealed source) that contains tritium. In an exit sign, the tubes are used to spell out the word “EXIT.”
- Never tamper with a tritium exit sign.
- A tritium exit sign should be clearly labeled with a statement that it contains tritium.
- Return outdated tritium exit signs to the manufacturer. The address of the manufacturer usually can be found on the back of the tritium exit sign. The manufacturer can provide instructions on how to ship the tritium exit sign safely.
Disposal of the broken sign should be arranged through the manufacturer or a health physics consultant. When an exit sign containing tritium is damaged and the sealed tube within the sign is broken, you should:
- Leave the sign alone; do not touch it.
- Evacuate the area immediately.
- Isolate the area; do not allow entry.
- Ventilate the area to the outside.
- Identify all individuals possibly exposed.
- If you think you have been contaminated, you should:
- Shower with soap and water (or at least wash face and hands).
- Change clothing and put the potentially contaminated clothes in a plastic bag for testing to confirm exposure.
- Drink plenty of fluids to help the tritium leave the body more quickly.
- Collect a urine sample for testing to confirm or rule out internal exposure.
- Call your local fire or police departments.
- Call your state's radiation control program.
- Call the manufacturer for technical information.
Resources
| Radionuclide
Technical Fact Sheets 28 February 2006. U.S. Environmental Protection Agency This page offers information on the final rule for radionuclides in drinking water, including tritium. |
| Tritium 30 November 2004. U.S. Environmental Protection Agency This page gives basic information on the radioactive element tritium. |
Cleanup
of broken tritium sign.
 July 13, 2004. Health Physics Society This site provides information on how to clean up broken exit signs. |
| Directory
of Agreement State and Non-Agreement State Directors and State
Liaison Officers. 20 June 2005. U.S. Nuclear Regulatory Commission This page provides a list of NRC-Agreement State contacts. |
| Ionizing
radiation. - 1910.1096, 1996.U.S. Department of Labor, Occupational Safety and Health Administration This page both gives and leads to additional information on worker health and safety standards for working with or around ionizing radiation sources. |
| NRC
Staff, Representatives of Three Firms to Meet July 10 to Discuss
Handling, Disposal of Signs Containing Tritium 3 July 1997. U.S. Nuclear Regulatory Commission This press release talks about NRC’s involvement in a case of a mishandled, broken exit sign. |
| Self-Powered
Radioactive Exit Signs
23 May 2005. Harvard University This page gives information on what tritium exit signs are, regulations around them, how to handle them and how to dispose of them. |
| Tritium
Illumination Devices
2004. New Jersey Department of Environmental Protection This page provides a list of manufacturers who can be contacted for the return and disposal of consumer product/devices that contain tritium. |
| Tritium
in Landfills Report
2005. Pennsylvania Department of Environmental Protection This site lists links to fact sheets about tritium and exit sign owner responsibility, and reports on radionuclide in landfills in Pennsylvania. |