Most modern domestic smoke detectors are now photoelectric, rather than ionization based.

Not only do they not contain toxic Americum 241, photoelectric smoke detectors are also both more sensitive to real fires and less prone to false alarms.

(The later is actually really important, as people will often disable smoke detectors in response to a false alarm - and then forget about them)

We had a kitchen smoke detector in college that was kept swaddled in plastic wrap at all times because it went off every. time. we tried to cook something. Absolutely a safety hazard, yeah.

…while it remains sealed in a layer of gold. It's not easy to get the Americium out.