Chemical, Biological, Radiological & Nuclear Defence
CBRN is an acronym referring to Chemical, Biological, Radiological, and Nuclear. It is in common use worldwide, generally to refer to protective measures taken against CBRN weapons or hazards.
As opposed to HAZMAT incidents which are accidental, CBRN incidents are deliberate, malicious acts with the intention to kill or sicken and disrupt society.
CBRN tasks are primarily concerned with conducting military operations within various hazardous environments (or the elimination or mitigation of those environments). These environments can be generated via the use of weapons, or they can be the result of accidental contamination of the environment.