Smoke Detector or Carbon Monoxide Detector

The most common type of smoke detector contains a small amount of Americium 241, a radioactive material. For this reason all detectors must, by law, be labeled as to radioactive content. However, it is legal to disposal of old smoke detectors in landfills or incinerators.   

You can also call the manufacturer for disposal. Federal law requires that the manufacturer take back the detectors. Most manufacturers accept small quantities at no charge.