This Report addresses in considerable detail the consequences of hot particles on and near the skin, in the eye, ear, respiratory system, and gastrointestinal tract. Limits for exposures from hot particles are recommended. If exposures are maintained below the recommended limits, few, if any, deterministic biological effects are expected to be observed, and those effects would be transient in nature. If effects from a hot-particle exposure are observed, the result is an easily treated medical condition involving an extraordinarily small stochastic risk. Such occurrences would be indicative of the need for improvement in radiation protection practices, but should not be compared in seriousness to exceeding whole-body exposure limits