Risks of radiation exposure to old military compasses with radioluminescent markings

This study investigates the radiological safety of handling old radioluminescent military compasses whose markings are coated with radium-based luminous paint, historically used to ensure better visibility in dim or night-time conditions until the 1960s, when its use was discontinued and eventually banned due to the mounting evidence of its harmful health effects, including the increased risk of cancer. Using gamma spectrometry, we confirmed radium presence in three historical compass models, namely M.49, M.53 S1, and the small Bézard model. We also measured ambient dose equivalent rates to assess ionising radiation exposure at the usual distances from the source during routine handling or long-term storage of these devices. Our findings indicate that, under certain conditions, radiation doses may exceed the recommended safety limits for general public and underscore the importance of raising awareness about potential radiological risks associated with antique navigation instruments. Our study points to the need for appropriate safety protocols, handling procedures, and storage conditions to minimise these risks among collectors of military memorabilia as well as the general public in line with the ALARA principle.