What sign indicates radiation hazards?

• A. Biohazard sign
• B. Laser sign
• C. Fire sign
• D. Radiation sign

Answer: (D)

Radiation hazards are signaled by the radiation symbol, a trefoil with three curved blades around a central point. This emblem, typically black on a bright yellow field, is placed on doors, walls, and equipment to warn that ionizing radiation (like X-rays or radioactive sources) is present. Seeing this sign means you should follow radiation safety practices—limit time near the source, increase distance, use shielding, and wear appropriate dosimetry and protective gear.

Other signs point to different dangers: a biohazard sign warns of biological materials, a laser sign indicates laser exposure risk, and a fire sign marks fire hazards. None of these convey ionizing radiation risk, which is why the radiation sign is the best indicator in this context.