Radiation Warning Symbol - Meaning, History, and Safety Significance #3498967 (License: Personal Use)

This iconic symbol, known as the trefoil, consists of a black circle with three yellow (or magenta) fan-shaped blades spaced at 120 degrees around a central circle. Designed in 1946 at the University of California, Berkeley, it was standardized by the International Organization for Standardization (ISO) and adopted globally to indicate the presence of potentially hazardous ionizing radiation. Its high-contrast color scheme ensures visibility and immediate recognition in safety-critical environments.

Used on containers, doors, equipment, and signage in nuclear facilities, medical radiology departments, laboratories, and transport vehicles carrying radioactive substances. Matches user intent for hazard awareness, regulatory compliance, emergency response, or educational content about radiation safety.