Unsafe levels of cancer-causing radon gas have been detected in 16 prisons, with 33 sites under investigation by the Ministry of Justice (MoJ).
HMP Dartmoor in Devon was closed in 2024 after levels of radon up to 10 times higher than the recommended limit were recorded in some areas. Hundreds of former prison staff and prisoners have signed up to a group legal action against the MoJ seeking compensation over their exposure.