It has been estimated that about 10 million sealed radioactive sources have been produced worldwide and at least 2 million are currently in use in the USA.9 They have many uses including medical treatment and diagnosis, industrial radiography, borehole logging, level gauges and even domestic smoke alarms. When they come to the end of their useful life, many will still constitute a significant potential hazard and, furthermore, may be too long lived and too radioactive for either decay storage or near-surface disposal. Most of the countries that own such sources have no nuclear infrastructure and do not, therefore, possess facilities where the sources can be safely stored, let alone disposed of; many fatalities have been caused by loss of control. In response, the IAEA has developed a Code of Conduct on the Safety and Security of Radioactive Sources. This aims to provide guarantees that, where decay storage is impractical, sources will be returned to the manufacturer at the end of life. For those sources that cannot be returned to the manufacturer (e. g. legacy sources), the IAEA BOSS (borehole disposal of sealed sources) system10 can be applied (see Section 18.5.5).