- Radioactive contamination is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids or gases (including the human body), where their presence is unintended or undesirable.
- Such contamination presents a hazard because of the radioactive decay of the contaminants,which emit harmful ionising radiation such as alpha or beta particles, gamma rays or neutrons. The degree of hazard is determined by the concentration of the contaminants,the energy of the radiation being emitted, the type of radiation, and the proximity of the contamination to organs of the body.
- It can occur in the event of a nuclear fallout (nuclear explosion), when the material is not properly sealed in the base container, during nuclear fuel processing, or in the event of natural calamities such as earthquake, tsunamis which mainly shut down its power supply.