For the purposes of Radiation Protection, radioactive waste can be defined as any Radioactive substances which is no longer required and has no further useful purposes. There are some exact definitions, some which relate to legal meaning. For example, in the Radioactive Substances Act 1993, radioactive waste is defined as '...a substance or article which, if it were not waste, would be radioactive material...' or '...a substance or article which has been contaminated in the course of the production, keeping or use of radioactive material, or by contact with or proximity to other waste..'. See Low-Level Waste (LLW).