When smoke detectors need to be replaced, don’t toss the broken safety devices into the trash; recycle them. According to the Environmental Protection Agency, the majority of smoke detectors in the U.S. contain a minute amount of a radioactive element called americium-241. It can take 432 years for the element to decompose safely in the ground. First Alert, the leading manufacturer of all types of detectors, will recycle its detectors free of charge. Mail the detector to 3920 Enterprise Ct., Aurora, Ill., 60504; mark the package, "For disposal only."