Chemical, biological, radiological, and nuclear hazards
Technological hazards originate from technological or industrial conditions, dangerous procedures, infrastructure failures or specific human activities. Chemical, biological, radiological and/or nuclear (CBRN) emergencies are accidents or deliberate acts involving CBRN hazards which are a subset of technological hazards. The umbrella term CBRN is commonly used because there are distinct similarities between these hazards, making some of the emergency preparedness and response measures or very similar for all of them.
Nuclear emergencies (includes nuclear hazards) involve or emerge from nuclear chain reactions. Such chain reactions take place under controlled circumstances for instance in nuclear power plants and research reactors. Nuclear chain reactions also occur in an uncontrolled manner in nuclear weapons, creating the enormous blast and heat effects associated with nuclear detonations.
Radiological emergencies (includes radiological hazards) can involve all other sources of radiation, such as radiography machines, radioactive material for use in industry, lost sources and more. Radiological accidents are usually not mass casualty events, as they commonly occur when people are irradiated by misplaced or misused radioactive equipment. They can however cause widespread fear among large parts of the population.
Chemical emergencies (includes chemical hazards) are defined as any unplanned event involving hazardous substances that causes or is liable to cause harm to health, the environment or property, such as loss of containment of hazardous substances and fires.
A biological emergency can occur when there is a major epidemic outbreak of diseases such as avian Influenza, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) etc., plant or animal contagion, insect or other animal plagues and infestations. Contamination can occur through natural exposure to the agent, accidental release of microorganisms from for example a research facility or by deliberate acts.