A radiological accident is an event that involves the release of potentially dangerous radioactive materials into the environment. This release is usually in the form of a cloud or "plume" and could affect the health and safety of anyone in its path. Radiological accidents can occur anywhere that radioactive materials are used, stored, or transported. Nuclear power plants, transport of radiological materials, and disposal of radioactive waste all pose risks. However, operations of facilities and the transport and disposal of radioactive waste are closely regulated by a variety of federal and local organizations, so the likelihood of an incident is remote. Nuclear power plant accidents will not cause the widespread destruction of a nuclear weapon nor will they produce radiation fallout. A power plant accident can cause an environmental radiation hazard by releasing radiation into the air. Thirty-eight states, particularly those in the eastern half of the contiguous 48 states and the West Coast States have a full power, licensed reactor on site. Nearly three million Americans live within 10 miles of an operating nuclear power plant.