A Practical Classification Approach for Chemical, Biological, Radiological and Nuclear (CBRN) Hazards Based on Toxicological and Situational Parameters

Abstract

Featured Application: The proposed CBRN hazard classification framework aims to integrate all CBRN silos’ hazard information, simplify it, and make it understandable for civil society and, particularly, for the potentially engaged groups. Sharing scientific background with the classifications used by emergency services and occupational safety, it can be directly applied by emergency responders, security services, and public safety agencies to rapidly assess and communicate risks during chemical, biological, radiological, nuclear, and energetic incidents. Integrating toxicological endpoints, exposure routes, and observable situational indicators into a unified, field-adapted system enables effective decision-making even when the hazardous agent is unidentified. This approach is especially valuable in the first minutes of an incident, supporting triage, protective action, and public warning, while also serving as a training and planning tool to enhance local and national CBRN preparedness. CBRN incidents are characterized by high uncertainty in terms of agent identity, dissemination methods, and situational context. This unpredictability complicates effective and timely response, especially in the initial phase before specialist services arrive, and lays the burden of applying protection and response measures on members of civil society participating in the incident. This paper proposes a structured classification framework for CBRN hazards to address this gap, integrating key characteristics from existing systems such as the GHS (Globally Harmonized System), WHO (World Health Organization) biosafety levels, and radiological exposure guidelines. The system emphasizes properties relevant for first responders and non-specialists, including observable effects, exposure routes, and hazard endpoints such as toxicity, virulence, and radiation dose. The goal is to enable rapid hazard recognition, improve communication, and support situational decision-making in public security scenarios.