Erudite colleagues, Our buildings are not situated within a radon affected area, but we tested for it anyway and found levels of exposure around half of the annual limit in one of our buildings. During a second period of monitoring one detector recorded a level just above the annual limit but seasonally corrected this came out as 2.5 times the annual exposure limit. Yet another period of monitoring and the levels are back down, but with one detector recording half the limit in an area above the original basement area which was monitored. My first thoughts were that the radon was emanating from the mass concrete structure, but now I have a problem with that as the latest monitoring reports a higher level of gas in an area which is physically higher than the basement and since radon is considerably heavier than air I would not have expected it to be present at a higher level than within the physically lower location adjacent. The only change which has taken place during these periods is the removal of some equipment from the lower area (redundant pc monitors, telephones and cables) which was temporarily stored in the upper area before disposal... Finally my question! Is there any possibility whatsoever that such equipment could potentially contain materials that might emit radon gas? As you can tell (probably) I am now clutching at straws! Many thanks Alan

Contact the HPA they ARE the radon experts. They like this sort of mystery. See http://www.hpa.org.uk/

They weren't placed in a warehouse full of smoke detectors were they? ;-)