What types of postings indicate a radiological hazard?

• A. Postings with yellow background and the three-bladed (tri-foil) radiation symbol
• B. Postings with red background and flame symbol
• C. Postings with blue border and wave symbol
• D. Postings with green background and leaf symbol

Answer: (A)

Radiological hazard postings are identified by the radiation warning symbol—a trefoil with three curved blades around a central circle—placed on a yellow background. This high-contrast, internationally recognized combination is used specifically to signal ionizing radiation danger, prompting procedures such as minimizing exposure, using shielding, and following strict safety controls in that area.

The other visuals indicate different hazards: a red background with a flame symbol warns of flammable materials, not radiation; a blue-bordered sign with a wave symbol is not used to signal radiological hazards; and a green background with a leaf symbol is not associated with radiation and typically relates to other safety or environmental cues.