The deposit and/or absorption of residual radioactive material or biological or chemical agents on or by structures, areas, personnel, or objects. •Nuclear Contamination. Residual radioactive material resulting from fallout or rainout, and residual radiation from a system produced by a nuclear explosion, and persisting longer than one minute after burst. •Biological Contamination. Microorganisms and toxins that cause disease in humans, plants, or animals or cause deterioration of material. •Chemical Contamination. Chemical substances intended for use in military operations to kill, seriously injure, incapacitate, or temporarily irritate humans.