The deposit and/or absorption of residual radioactive material or biological or chemical agents on or by structures, areas, personnel, or objects. Chemical contamination is chemical substances intended for use in military operations to kill, seriously injure, incapacitate, or temporarily irritate or disable man through their physiological effects. Biological contamination is micro­organisms and toxins that cause disease in man, plants, or animals, or cause the deterioration of materiel. Radiological contamination is residual radioactive material resulting from fallout or rainout, and residual radiation from a system produced by a nuclear explosion (e.g., Nuclear Indirect Gamma Activity (NIGA)), and persisting longer than one minute after burst.