Missoula Technology and Development Center Facilities Toolbox: Hazardous Substances in Buildings
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Will smoke detectors cause radiation poisoning?

No. Fires kill people but smoke detectors don't even irradiate them.

Photo of a smoke detector.Ionization chamber and photoelectric smoke detectors are the two most common types. Both work very well and are safe to use.

There are no health concerns with photoelectric smoke detectors because no radiation is involved. Photoelectric smoke detectors sound an alarm when smoke particles scatter a beam of light in the detection chamber. They respond quickly to fires with lots of smoke.

Ionization chamber smoke detectors contain a small amount of americium-241, a radioactive material. Smoke particles disrupt the low, steady electrical current produced by radioactive particles and trigger the detector's alarm. They react quickly to fires that give off little smoke. Ionization smoke detectors expose people to a tiny amount of radiation—about 1/100 of a millirem per year. This is well below the background radiation level of about 360 millirems a year. If a smoke detector contains radioactive materials, a printed notice on the packaging will say so.

Because of the long half-life of americium-241, the amount of radioactive material in an ionization chamber smoke detector at the end of its useful life will be about the same as when it was purchased. State and local requirements for disposal of ionization smoke alarms vary. Some States conduct an annual roundup of ionization smoke detectors similar to that for hazardous household chemicals. Others allow ionization smoke detectors to be thrown out with ordinary trash but recommend that used smoke alarms be returned to the supplier. Some States require that used smoke detectors be returned to the supplier. Check with your local solid waste district, hazardous waste program, or health department to find out the procedures in your area. All manufacturers of ionization smoke detectors must accept returns—when in doubt, return the detector. Return addresses are listed in the product warranty or use instructions.

Smoke detector batteries should be disposed of as explained in What should I do with dead batteries?

Health Issues: Radiation can cause cancer and other problems, including defects in unborn children. Radiation produced during normal use of ionization smoke detectors is so low it has no noticeable effect. If the ceramic chamber containing the radioactive material is removed and swallowed, exposure is about six times the desirable yearly exposure—still too low to cause acute health effects.


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