Chemical, Biological, Radiological, and Nuclear (CBRN) refers to a range of hazardous materials that can pose significant risks to human health and safety. Chemical agents can include toxic substances like nerve gas, while Biological agents involve pathogens such as bacteria or viruses that can cause disease. Radiological threats involve the release of radioactive materials, which can lead to contamination and health risks. Lastly, Nuclear threats pertain to the use of nuclear weapons or accidents at nuclear facilities. Together, these categories represent critical areas of concern for emergency response and public safety.