3 ms·

There are also old smoke detectors that contain alpha-emitting americium. https://www.epa.gov/radtown/americium-ionization-smoke-detectors https://www.epa.gov/

• geerlingguy 6y ago
  Those are common and still sold everywhere (I have 6 of them around my house). As long as you don't chop up your smoke detector or try eating it, it's not a big risk.