Answer to Question #9737 Submitted to "Ask the Experts"

Category: Consumer Electronic Products — Smoke Detectors

The following question was answered by an expert in the appropriate field:


Yesterday I opened the cover of my smoke detector in my caravan to clean it. I could see the americium source and was surprised to see something like a clean disk in stainless steel or aluminum (about 1 cm in diameter) with two little black dots on it. With my spotlight I saw that the black spots were shining gold, so I suppose that was the americium. Is this dangerous?


You are worrying unnecessarily. I seriously doubt that what you saw was americium. I would contact the manufacturer and describe what you have seen. The amount of americium-241 in a smoke detector is so small that it simply is not considered hazardous to your health.

Smoke detectors are safe. They were tested for extreme environments including fire, water from fire departments, leachability, and tampering. The radioactivity is simply not easily removed, and even if somehow ingested, it is in a form that would not be considered hazardous.

Now, some detailed information. Smoke detectors were tested extensively prior to even being authorized for use in smoke detectors by the U.S. Nuclear Regulatory Commission (NRC), the agency responsible for licensing exempt sources of radioactive materials. NRC takes very seriously the concerns that there is the radionuclide americium-241 in smoke detectors. However, before any amount of radioactivity was authorized in smoke detectors, NRC performed several technical analyses in the 1970s, in 1981 and, most recently, in 2001 to determine if NRC's earlier calculations regarding any potential health effects from use of such consumer products containing very small amounts of radioactivity would be detrimental before authorizing its use.

NUREG 1717, which is available on NRC's website, discusses the radiological assessment that NRC performed for smoke detectors and other types of consumer products. Radiation doses were estimated for the normal life cycle of the smoke detector, covering routine uses as well as inadvertent uses of the device (such as many thousands of smoke detectors burning in a warehouse fire).

Americium-241 used in smoke detectors is embedded (fused) onto a layer of foil; it does not pose any danger to you or your family. This is one of the reasons NRC originally authorized its use in the 1970s. The americium-241 cannot be scraped off or inhaled.

For additional information, I again refer you to our Health Physics Society website.

I hope this helps.

Orhan Suleiman, MS, PhD

Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. To convert these to traditional units we have prepared a conversion table. You can also view a diagram to help put the radiation information presented in this question and answer in perspective. Explanations of radiation terms can be found here.
Answer posted on 7 June 2011. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.