As long as human beings are only exposed to radiation levels below the standard, worldwide studies have not yet revealed any danger from either thermal or more importantly, non-thermal effects. Therefore, the weight of scientific evidence is against humans entering areas where radiation levels are higher than the limits for cumulative levels established by ARPANSA. For the general public there is usually little opportunity to enter these areas, however, it is members of the public who work close to antennas, for example, security personnel, window cleaners, lift and air-conditioning technicians and water reservoir maintenance personnel, who while legally "members of the public" under the ARPANSA Standard, run the risk of experiencing radiation levels higher than the standard with consequent increased danger of injury from both thermal and non-thermal effects. For these situations, the Alliance was the first to develop NATA accredited modelling techniques for the near field as an inexpensive first cut worst case assessment of exposure risk.