Radiation Hazard Symbol - Meaning, Usage, and Safety Information #3893032 (License: Personal Use)

This iconic yellow-and-black radiation symbol, known as the trefoil, consists of three black equilateral triangles spaced 120 degrees apart around a central circle, all enclosed in a yellow circle with a black border. Designed in 1946 at the University of California, Berkeley, it visually conveys danger from ionizing radiation and is standardized by ISO 361 and IAEA guidelines. It appears on containers, equipment, and facilities handling radioactive substances to ensure immediate recognition and compliance with safety regulations.

Used on signage, packaging, lab equipment, nuclear facilities, and medical imaging devices to warn personnel and the public of radiation hazards; matches user intent for safety education, regulatory compliance, or emergency response guidance.