Prisoners in Dartmoor Prison are being moved to other accommodation on the site after the potentially harmful gas radon was detected.

Prolonged or concentrated exposure can lead to severe illness, so there are statutory requirements for periodic testing for its presence.

A Prison Service spokesperson said: “A small number of prisoners are being relocated as a precautionary measure after routine testing revealed higher than normal levels of radon.

 “This is a temporary measure while work to permanently reduce radon levels is completed and there are no safety implications to staff or prisoners who remain on site.”

The Prison Service has been monitoring levels of radon in HMP Dartmoor and taken some steps to address initial results and protect prisoners and staff.  These include closing or restricting access to certain areas affected and the introduction of additional ventilation to assist air movement.

Radon is naturally occurring in nature and commonly associated in higher concentrations than average with granite, especially on Dartmoor which has an underlying granite geology.