Two common types of smoke detectors are ionization detectors and photoelectric detectors. Ionization-type smoke detectors contain a small amount of radioactive material. For these detectors, it is required by law to have a warning label, usually found on the “back” of the detector, or the part facing the mounting base that is connected to the wall. Photoelectric-type smoke detectors do not contain radioactive material.
Household Ionization Smoke Detectors
Detector Manufacturer: mail the detector to the manufacturer. Manufacturer name should be listed on the back of the detector, in the instruction booklet or warranty.