Which description best identifies an internal hazard?

• A. Radioactive material inside the body that remains hazardous until it decays or is eliminated
• B. Radioactive material outside the body
• C. Surface contamination only
• D. Environmental contamination in air

Answer: (A)

An internal hazard is radioactive material that has entered the body. Once inside—by inhalation, ingestion, or through a wound—it can irradiate tissues from within and continue to pose a risk as it decays or as the body gradually eliminates it. This persistence is what makes internal hazards distinct from external sources or surface contamination, which can often be mitigated by removing the source or decontaminating the skin. Materials inside the body can affect sensitive organs for a longer period, requiring medical management to reduce uptake and assist elimination, whereas surface or environmental contamination is addressed through surface decontamination and shielding.