4.1. The requirements for protection and safety for workers in emergency exposure situations are set out in GSR Part 3 [2] and in IAEA Safety Standards Series No. GSR Part 7, Preparedness and Response for a Nuclear or Radiological Emergency [30].
4.2. There are four groups of workers who may be exposed in a nuclear or radiological emergency, owing either to their involvement in the emergency response or to the nuclear or radiological emergency at a facility or an activity itself:
(a) Emergency workers who have specified duties;
(b) Workers performing their duties in workplaces and not being involved in the response to a nuclear or radiological emergency;
(c) Workers who are requested to stop performing their duties in workplaces and to leave the site;
(d) Workers who are accidentally exposed as a result of an accident or other incident at a facility or during the conduct of an activity and whose exposure is not related to the emergency response.
4.3. These four groups are derived from considerations of a wide range of scenarios as well as different duties and responsibilities of workers in a facility or activity (such as designated emergency workers, administrative staff at the site and employees of nearby operational units). The duties of different workers in a nuclear or radiological emergency will differ and appropriate protection strategies should be applied to ensure adequate protection of all workers. Protection of emergency workers as specified in para. 4.2(a) should be provided in line with the requirements set out in GSR Part 3 [2] for emergency exposure situations and in GSR Part 7 [30]. Protection of workers grouped in para. 4.2(b) should be provided in the same way as for workers in planned exposure situations in line with the requirements set out in GSR Part 3 [2]. Protection of workers grouped in para. 4.2(c) should be provided in the same way as for members of the public in emergency exposure situations in line with the requirements set out in GSR Part 7 [30]. Protection of workers who are accidentally exposed (para. 4.2(d)) in connection with medical follow-up and treatment and dose assessment should be in line with GSR Part 3 [2] and GSR Part 7 [30].
4.4. Protection of helpers in an emergency (i.e. members of the public who willingly and voluntarily help in response to a nuclear or radiological emergency) is not specifically addressed in this Safety Guide. However, helpers in an emergency should be registered, should be integrated into the emergency response operations and should be provided with the same level of protection as for emergency workers not designated as such at the preparedness stage, in accordance with GSR Part 7 [30].
EMERGENCY PLANNING AND RESPONSIBILITIES
4.5. Arrangements for the protection of workers in a nuclear or radiological emergency should be included in the emergency plan that is prepared on the basis of the hazard assessment in accordance with GSR Part 7 [30]. The degree of planning should be commensurate with the nature and magnitude of the risks, and the feasibility of mitigating the consequences if an emergency were to occur.
4.6. With regard to the protection of emergency workers, the emergency plan should include the following:
(a) The persons or organizations responsible for ensuring compliance with requirements for protection and safety for workers in a nuclear or radiological emergency, including those for controlling the exposure of emergency workers;
(b) Specified roles and responsibilities of all workers involved in the response to a nuclear or radiological emergency;
(c) Details of adequate protective actions to be taken, personal protective equipment and monitoring equipment to be used, and dosimetry arrangements;
(d) Consideration of access control for workers in a nuclear or radiological emergency on the site.
PROTECTION OF EMERGENCY WORKERS
4.7. The fundamental difference between members of the public and emergency workers in an emergency exposure situation is that members of the public could receive doses unless some action is taken to prevent it, whereas emergency workers will receive doses owing to specified duties assigned to them. Thus, to the extent possible, it is reasonable to continue to treat emergency workers’
exposures according to the requirements for planned exposure situations, in accordance with the graded approach, in particular in the later stages of the emergency. The exposure of emergency workers starts with the assignment to undertake a particular action and finishes with completion of the assigned task or declaration of termination of the emergency.
4.8. Protection of emergency workers should include, as a minimum:
(a) Training of emergency workers designated as such in advance;
(b) Providing instructions immediately before their use to those emergency workers not designated as such in advance8 on how to perform their specified duties under emergency conditions and on how to protect themselves (‘just in time training’);
(c) Managing, controlling and recording the doses received;
8 Emergency workers who are not designated as such at the preparedness stage are required to be registered and integrated into the emergency response operations in line with GSR Part 7 [30].
(d) Provision of appropriate, specialized personal protective equipment and monitoring equipment;
(e) Provision of iodine thyroid blocking, where appropriate;
(f) Medical follow-up and psychological counselling, as appropriate;
(g) Obtaining the informed consent of emergency workers to perform specified duties, where appropriate.
Justification
4.9. At the preparedness stage, the protective actions and other response actions to be taken in a nuclear or radiological emergency should be justified. Due consideration should be given to the detriment associated with doses received by the emergency workers who take protective actions and other response actions.
There should be a commitment to the justification process by all interested parties (the regulatory body, response organizations and others).
Optimization
4.10. At the preparedness stage, the process of optimization, including the use of reference levels, should be applied to the protection of workers. There should be a commitment to the optimization process by all interested parties (the regulatory body, response organizations and others).
4.11. As part of the process of optimization, reference levels should be established. A reference level should represent the level of dose above which it is judged to be inappropriate to plan to allow exposures to occur and for which protective actions should therefore be planned and optimized. The doses to be compared with the reference levels are usually prospective doses (i.e. doses that might be received in the future, as it is only those future doses that can be influenced by decisions on protective actions). The reference levels are not intended as a form of retrospective dose limit.
4.12. The initial phase of the response to a nuclear or radiological emergency is characterized by a lack of information about the event, a scarcity of materials for protective measures and the need for urgency in implementing protective actions.
Therefore, there is little or no scope for applying the optimization process when managing the protection of emergency workers during this initial phase. Efforts should be aimed at reducing any exposures as far as practicable, with account taken of the difficult conditions of the evolving emergency.
4.13. In taking protective actions during the late phase of a nuclear or radiological emergency and at the transition from an emergency exposure situation to an existing exposure situation, the optimization process should be applied to the protection of emergency workers in the same way as for the protection of workers in planned exposure situations.
Restricting exposure of emergency workers
4.14. As the exposure of emergency workers is intentional and controlled, the dose limits for workers should be assumed to apply unless there are overriding reasons not to apply them. As stated in para. 4.15 of GSR Part 3 [2] (see also para. 5.55 of GSR Part 7 [30]):
“Response organizations and employers shall ensure that no emergency worker is subject to an exposure in an emergency in excess of 50 mSv other than:
(a) For the purposes of saving life or preventing serious injury;
(b) When undertaking actions to prevent severe deterministic effects and actions to prevent the development of catastrophic conditions that could significantly affect people and the environment; or
(c) When undertaking actions to avert a large collective dose.”
4.15. Guidance values for restricting the exposure of emergency workers should be defined in accordance with the assigned task as provided in appendix I of GSR Part 7 [30] and reproduced in Table 2 of this Safety Guide. Where actions for the purposes of saving life are concerned, every effort should be made to keep individual doses of emergency workers below 500 mSv for exposure to external penetrating radiation, while other types of exposure should be prevented by all possible means. However, in estimating doses to emergency workers, the exposures via all pathways, external and internal, should be assessed and should be included in the total. The value of 500 mSv should be exceeded only under circumstances in which the expected benefits to others clearly outweigh the emergency worker’s own health risks, and in which the emergency worker volunteers to take the action and understands and accepts this health risk.
4.16. Regardless of the circumstances, response organizations and employers should make all reasonable efforts to keep the doses received by emergency workers below the thresholds for severe deterministic effects given in GSR Part 3 [2], GSR Part 7 [30] and GSG-2 [31].
4.17. When military personnel are designated as emergency workers, every effort should be made to ensure that they are protected in the same way as other emergency workers.
TABLE 2. GUIDANCE VALUES FOR RESTRICTING EXPOSURE OF EMERGENCY WORKERS [30]
Task Guidance valuea
Lifesaving actions Hp(10)b < 500 mSv Ec < 500 mSv ADTd < ½ADTe
This value may be exceeded — with due
consideration of the generic criteria in table II.1 of GSR Part 7 [30] — under circumstances in which the expected benefits to others clearly outweigh the emergency worker’s own health risks, and the emergency worker volunteers to take the action and understands and accepts these health risks.
Actions to prevent severe deterministic effects and actions to prevent the development of catastrophic conditions that could significantly affect people and the environment
Hp(10)b < 500 mSv Ec < 500 mSv ADTd < ½ADTe
Actions to avert a large collective dose Hp(10)b < 100 mSv Ec < 100 mSv ADTd < 0.1ADTe
a These values are set to be two to ten times lower than the generic criteria in table II.1 of GSR Part 7 [30] and they apply for:
(a) The dose from external exposure to strongly penetrating radiation for Hp(10). Doses from external exposure to weakly penetrating radiation and from intake or skin contamination need to be prevented by all possible means. If this is not feasible, the effective dose and the RBE weighted absorbed dose to a tissue or organ have to be limited to minimize the health risk to the individual in line with the risk associated with the guidance values given here.
(b) The total effective dose E and the RBE weighted absorbed dose to a tissue or organ ADT via all exposure pathways (i.e. both dose from external exposure and committed dose from intakes) which are to be estimated as early as possible in order to enable any further exposure to be restricted as appropriate.
b Personal dose equivalent Hp(d) where d = 10 mm.
c Effective dose.
d RBE weighted absorbed dose to a tissue or organ.
e Values of RBE weighted absorbed dose to a tissue or organ given in table II.1 of GSR Part 7 [30].
MANAGING THE EXPOSURE OF EMERGENCY WORKERS
4.18. In terms of para. 4.12 of GSR Part 3 [2], the government is required to establish a programme for managing, controlling and recording the doses received by emergency workers in a nuclear or radiological emergency. Response organizations and employers should implement this programme.
4.19. The group of emergency workers specified in para. 4.2(a) can be further divided into three categories of emergency worker:
(a) Category 1. Emergency workers undertaking mitigatory actions and urgent protective actions on the site, including lifesaving actions, actions to prevent serious injury, actions to prevent the development of catastrophic conditions that could significantly affect people and the environment, actions to prevent serious deterministic effects and actions to avert a large collective dose. Emergency workers in Category 1 are required to be designated as such at the preparedness stage. They are likely to be operating personnel at the facility or undertaking the activity, but they may be personnel from the emergency services. They are employed either by a registrant or licensee (operating organization) or by a response organization, and they should receive training in occupational radiation protection.
(b) Category 2. Emergency workers undertaking urgent protective actions off the site (e.g. evacuation, sheltering and radiation monitoring) to avert a large collective dose. They are most likely to be police, firefighters, medical personnel, and drivers and crews of evacuation vehicles. Every effort should be made to designate emergency workers in Category 2 as such at preparedness stage. They are to have pre-specified duties in an emergency response and should receive training in occupational radiation protection on a regular basis as first responders. They are not normally considered to be occupationally exposed to radiation, and their employers are response organizations.
(c) Category 3. Emergency workers undertaking early protective actions and other response actions off the site (e.g. relocation, decontamination and environmental monitoring) as well as other actions aimed at enabling the termination of the emergency. Emergency workers in Category 3 may or may not be designated as such at the preparedness stage. They may or may not normally be considered to be occupationally exposed to radiation, and they may or may not have received any relevant training, including training in radiation protection.
4.20. Any limit in the duration of work undertaken by emergency workers and any conditions on which they will conduct the work should be applied by planning the emergency work on the basis of guidance values of dose.
4.21. Tasks should be assigned, depending on the category of emergency worker, as follows:
(a) Category 1 emergency workers should carry out actions to save lives or prevent serious injury, actions to prevent severe deterministic effects and actions to prevent the development of catastrophic conditions that could significantly affect people and the environment.
(b) Category 2 emergency workers should not be the first choice for taking lifesaving actions.
(c) Category 1 and Category 2 emergency workers should carry out actions to avert a large collective dose.
(d) Category 3 emergency workers should carry out those actions in which they will not receive a dose of more than 50 mSv.9
4.22. In almost all emergencies, at best only the dose from external penetrating radiation will be measured continuously. Consequently, the operational guidance provided to emergency workers should be based on measurements of penetrating radiation (e.g. as displayed on an active or self-reading dosimeter). Doses from intakes, skin contamination and exposure of the lens of the eye should be prevented by all possible means, for instance by the use of personal protective equipment, iodine thyroid blocking (where exposure due to radioactive iodine might be involved) and by the provision of instructions concerning operations in potentially hazardous radiological conditions. Such instructions should cover the application of time, distance and shielding principles, the prevention of ingestion of radionuclides and the use of respiratory protection. Available information about radiological conditions on the site should be used to aid decisions on the appropriate protection of emergency workers.
4.23. Female workers who are aware or who suspect that they are pregnant or who are breast-feeding should be encouraged to notify their employer and they should typically be excluded from tasks in an emergency unless such tasks can be carried out within the requirements for occupational exposure set out in paras 3.114 and 4.15 of GSR Part 3 [2]. Female workers designated as emergency workers prior to an emergency and who are aware or who suspect that they are
9 Helpers in an emergency should not be allowed to take actions that might result in their exceeding an effective dose of 50 mSv.
pregnant or who are breast-feeding during the emergency may volunteer to take emergency duties as long as para. I.4 of GSR Part 7 [30] is applied.
4.24. Response organizations and employers are required to ensure that emergency workers who undertake actions in which the doses received might exceed 50 mSv (see para. 4.14 of this Safety Guide, para. 4.17 of GSR Part 3 [2]
and para. 5.57 of GSR Part 7 [30]) do so voluntarily. Such emergency workers should be clearly and comprehensively informed in advance of the associated health risks, as well as of available protective measures, and they should be trained, to the extent possible, in the actions that they are required to take. The voluntary basis for response actions by emergency workers is usually covered in the emergency arrangements.
4.25. Workers should not normally be precluded from incurring further occupational exposure because of doses received in an emergency.
ASSESSMENT OF EXPOSURE
4.26. Response organizations and employers should take all reasonable steps to assess and record the exposures received by workers in an emergency. Once the total dose received by emergency workers via all exposure pathways (including the committed doses from intakes) has been estimated, the guidance provided in Table 2 for the effective dose and the RBE weighted absorbed dose to a tissue or organ should be used for restricting further exposure in response to a nuclear or radiological emergency. The doses from exposures of emergency workers in an emergency response and from exposures of workers who are accidentally exposed (see para. 4.2(d)) should, if possible, be recorded separately from those doses incurred during routine work, but should be noted in the workers’ records of occupational exposure.
4.27. The degree of accuracy required for any assessment of exposure should increase with the level of exposure likely to have been received by the worker.
Some pre-established guidance can help in the management of exposures of emergency workers in Category 1, expressed in terms of dose and directly measurable quantities such as dose rate or air concentration. The exposures of emergency workers should be monitored on an individual basis, by using means appropriate to the situation, such as direct reading dosimeters or alarm dosimeters.
4.28. Records of occupational exposure should be generated and maintained in a simplified standard format by all response organizations and employers to avoid
confusion. Information on the doses received and on the associated health risks should be communicated to the emergency workers involved.
4.29. The guidance given in paras 7.222 and 7.223 may also be relevant for emergencies.
MEDICAL ATTENTION
4.30. Emergency workers and accidentally exposed employees should receive medical attention that is appropriate for the doses that they may have received (see paras 10.29–10.34). Screening based on equivalent doses to specific radiosensitive organs as a basis for medical follow-up and counselling should be provided if an emergency worker or an accidentally exposed employee has received an effective dose exceeding 100 mSv over a period of a month or if the worker so requests. Although an emergency worker or an accidentally exposed employee who receives doses in a nuclear or radiological emergency should normally not be precluded from incurring further occupational exposure, qualified medical advice should be obtained before allowing further occupational exposure where a person has received an effective dose exceeding 200 mSv.
Such advice should also be made available at the request of the worker. Such qualified medical advice is intended to assess the continued health and fitness of the worker in line with GSR Part 3 [2] and GSR Part 7 [30].
4.31. A particular concern should be whether a worker has received a dose sufficient to cause severe deterministic effects. If the dose received by the worker exceeds the thresholds for severe deterministic effects specified in table IV.1 of
4.31. A particular concern should be whether a worker has received a dose sufficient to cause severe deterministic effects. If the dose received by the worker exceeds the thresholds for severe deterministic effects specified in table IV.1 of