Check the expiry date on your smoke alarms. This is usually located on the bottom or side of the alarm. If your smoke alarm does not have an expiry date, it is best to replace it.
Two main types of smoke detectors are available for household use: photoelectric and ionisation smoke detectors. Photoelectric smoke detectors are activated by large particles in smoke and are good at detecting fires that smoulder. Ionisation smoke detectors contain a very small amount of radioactive material and detect the charged particles that come off flaming fires.
Buy long-life photoelectric smoke alarms with inbuilt 10-year lithium batteries which last as long as the smoke alarm, then you won’t need to worry about replacing them every year.
We're looking into this. (The only company we've found which recycles smoke alarm components in New Zealand is located in Christchurch.)
When your smoke alarm fails, you can put it out in your normal rubbish disposal.
On average, a cubic metre of New Zealand soil is about as radioactive as 13 smoke alarms therefore disposing of smoke alarms to landfill doesn’t change the landfill’s overall radioactivity.