Protecting people against radiation exposure in the event of a radiological attack

Abstract

This report responds to a widely perceived need for professional advice on radiological protection measures to be undertaken in the event of a radiological attack. The report, which is mainly concerned with possible attacks involving “radioactive dispersion devices”, re-affirms the applicability of existing ICRP recommendations to such situations, should they ever occur. Many aspects of the emergency scenarios expected to arise in the event of a radiological attack may be similar to those that experience has shown can arise from radiological accidents, but there may also be important differences. For instance, a radiological attack would probably be targeted at a public area, possibly in an urban environment, where the presence of radiation is not anticipated and the dispersion conditions commonly assumed for a nuclear or radiological emergency, such as at a nuclear installation, may not be applicable. First responders to a radiological attack and other rescuers need to be adequately trained and to have the proper equipment for identifying radiation and radioactive contamination, and specialists in radiological protection must be available to provide advice. It may be prudent to assume that radiological, chemical, and/or biological agents are involved in an attack until it is proven otherwise. This calls for an “all-hazard” approach to the response. In the aftermath of an attack, the main aim of radiological protection must be to prevent the occurrence of acute health effects attributable to radiation exposure (termed “deterministic” effects) and to restrict the likelihood of late health effects (termed “stochastic” effects) such as cancers and some hereditable diseases. A supplementary aim is to minimise environmental contamination from radioactive residues and the subsequent general disruption of daily life. The report notes that action taken to avert exposures is a much more effective protective measure than protective measure the provision of medical treatment after exposure has occurred. Responders involved in recovery, remediation and eventual restoration should be subject to the usual international standards for occupational radiological protection, which are based on ICRP recommendations, including the relevant requirements for occupational dose limitation established in such standards. These restrictions may be relaxed for informed volunteers undertaking urgent rescue operations, and they are not applicable for voluntary life-saving actions. However, specific protection measures are recommended for female workers who may be pregnant or nursing an infant. The immediate countermeasures to protect the public in the rescue phase are primarily caring for people with traumatic injuries and controlling access. Subsequent actions include respiratory protection, personal decontamination, sheltering, iodine prophylaxis (if radioiodines are involved), and temporary evacuation. In the recovery phase, the relocation and resettlement of people may be needed in extreme cases. This phase may require remedial action, including cleanup, management of the resulting radioactive waste, management of any human remains containing significant amounts of radioactive substances, and dealing with remaining radioactive residues. The guidance given in relation to public protection is based solely on radiological protection considerations and should be seen as a decision-aiding tool to prepare for the aftermath of a radiological attack. It is expected to serve as input to a final decision-making process that may include other societal concerns, consideration of lessons learned in the past (especially these involving the public perception of the risks posed by radioactive contamination) and the participation of interested parties. A radiological attack could also be the cause of radioactive contamination of water, food, and other widely consumed commodities. This possible outcome is considered unlikely to lead to significant internal contamination of a large number of people owing to the large amounts of radioactive material that would be required to cause high levels of contamination of water, food, and other commodities. Nonetheless, the report recommends radiological criteria for restricting the use of commodities under such circumstances. The report concludes by reiterating that the response to radiological attacks should be planned beforehand following the customary processes for optimisation of radiological protection recommended by ICRP, and that optimised measures should be prepared in advance. Such plans should result in a systematic approach that can be modified if necessary to take into account the prevailing conditions and to invoke actions as warranted by the circumstances. Many potential scenarios clearly cannot induce immediate severe radiation injuries. Therefore, in order to prevent over-reaction, response measures prepared in advance should reflect the real expected gravity of the various possible scenarios.