Under the Ionising Radiation Regulations the store was designated a controlled area and the 750 radioactive minerals identified were separated and spread out in less restricted storage space. Both gamma detectable and contamination monitor detected minerals were re-stored in this way. Due to the friable condition of some minerals, a subsequent survey of the store was made to check against contamination by the move. The only unexpected radiation detected was on the disposable filter of the air conditioning. After unsuccessful replacement of the filter, it was realised that this was radon radiation resulting from the decay of uranium and thorium minerals.
Radon is soluble in water and in body fluids.
This discovery initiated a radon survey which revealed unsafe levels of radon within the store, and contamination of the rest of the building. The decision was taken to remove all radioactive materials to a separate store with extract system, isolation shutters and fan failure alarms. Moving away from radioactivity, Barry Marshall of The Science Museum spoke about the hazards associated with industrial materials. PCBs are found in coolant oils. They are a non-conductor of electricity and were used extensively until being banned in the 1970s.