Smoke detectors are a must to have in the home to help protect you and your family in case of fire. But over time, smoke detectors need to be replaced. When it's time to replace them, keep in mind that it is illegal to throw them in the trash. The majority of smoke detectors contain something called "ionizing radiation," which is what helps it detect smoke. Since this is a radioactive material, old detectors cannot be landfilled. Instead, bring them to a household hazardous waste collection drop-off when your community has one planned. When you do get a new detector, look for photoelectric models, which are not radioactive, can detect smoke and are easier to recycle.