Smoke detectors self-expire after 10 years. Ionizing detectors have radioactive Ameriicum-241 in them. They're exceptionally difficult to recycle. It seems like here in SF I have to ship them to the manufacturer, Kidde, who no longer advertises their recycling program.

I wonder how many of them are just dumped into landfill and are causing untold problems.

Perhaps the answer is to collect enough to make my own backyard reactor. Then the gov’t will come clean it up for free.