Radioactive Warning Symbol - International Ionizing Radiation Hazard Sign #281421 (License: Personal Use)

This is the international ionizing radiation warning symbol, commonly known as the trefoil, featuring three black blades spaced at 120 degrees on a yellow circular background with a central black circle. Adopted in 1946 at the University of California, Berkeley, it signifies the presence of potentially hazardous radioactive material or radiation fields. Its high-contrast design ensures immediate recognition and compliance with global safety standards.

Used on containers, doors, equipment, and signage in nuclear facilities, medical imaging labs, research centers, and transport vehicles carrying radioactive substances. Matches user intent for safety education, regulatory compliance, hazard identification, or academic reference.