London: HMP Dartmoor men's prison in the British town of Princetown temporarily closed 184 cells and transferred 194 prisoners between November and February due to detected radon contamination, Sky News reported.
"A number of prisoners have been relocated as a precautionary measure after routine testing revealed higher than normal levels of radon," a spokesperson for the prison was quoted as saying by the broadcaster.
The report added that the relocation of inmates is a "temporary measure" amid work to "permanently reduce" radon levels in the building.
According to the broadcaster, the increase in radiation levels could be caused by the high concentration of granite in the air.