A DC driven ionisation apparatus is provided for ionising a local atmosphere in which a corporeal surgical or cosmetic procedure is to be performed, the ionisation apparatus including a safety circuit comprising detector means for detecting when a hazard condition exists, such as a short circuit or high charge level condition, a circuit controller for actuating switch means to turn the DC supply off and thereafter to cyclically reconnect and disconnect the DC supply until the hazard condition has been rectified, and re-set means for thereafter re-setting a continuous DC supply to the circuit until the next occurrence of a hazard condition or until the procedure is complete.
