Spain’s Nuclear Security Council (CSN) announced on Tuesday a piece of equipment containing two possible sources of radioactivity has disappeared in the Spanish city of Seville. The equipment was stored in an orange case and used to measure ground density and humidity. It contains caesium 137 and americium 241 which emit low levels of radioactivity and was taken from a vehicle belonging to an engineering, quality control and construction company. Caesium 137 and americium 241 are considered to be fourth category radioactive sources on a scale of 1-5 where 5 is the least dangerous. Category 4 is defined as substances which are “probably not dangerous for people,” as they are contained in measuring equipment. However, the CSN warned there could be a risk if the equipment is manipulated or destroyed. They advise anyone who discovers the case to inform security services.