Uncertainty under collaboration: A case of a maritime radiological and nuclear incident in the Arctic

• Radiological emergency response in civilian maritime setting is an emerging topic. • Data from a radiological and nuclear emergency response exercise, Arctic REIHN. • Emergency without understanding of radiation creates unique uncertainties. • Uncertainty typologies. • Collaboration gaps and suggestions to improve operational handling and risk communication. During a complex emergency response where the experience and knowledge of the hazard itself and the exact consequences are not well known, decisions must be taken under uncertainty, as soon as possible, and in collaboration with several stakeholders. Radiological emergency response in the civilian maritime setting has, in recent years, become an emerging topic. Uncertainties and risks faced by emergency response organizations during these events have not been examined as much as other maritime emergencies and, therefore, lack analysis during realistic conditions. Through interviews, participant observation, and secondary data from a radiological and nuclear emergency response exercise, Arctic REIHN, we examined how participants experienced uncertainty under a complex collaborative exercise environment and how those uncertainties influenced emergency response efforts. We found that the type of emergency itself, combined with a lack of understanding of radiation, created unique uncertainties that amplified the complexity. The lack of situational understanding during the initial stages of the incident and the reliance on expert assessments of radiation created decision uncertainties regarding safety and response options when the reaction time was limited. Epistemic and pragmatic uncertainties linked to roles and procedures further hamper critical collaborative efforts. Our findings contribute to uncertainty typologies and may be utilized in developing collaboration strategies between organizations to strengthen operational handling and improve risk communication.