All materials and products eventually come to the end of their useful life, and those made with nanotechnology are no different. This means that engineered nanomaterials will ultimately enter the waste stream and find their way into landfills or incinerators—and eventually into the air, soil and water. As a result, it is important to consider how various forms of nanomaterials will be disposed of and treated at the end of their use, and how the regulatory system will treat such materials at the various stages of their lifecycle.