Biohazard Symbol - Universal Warning Sign for Biological Hazards #1478394 (License: Personal Use)

This high-contrast red-on-white biohazard symbol is a standardized warning sign used globally to indicate the presence of biological substances that pose a threat to human health. Its distinctive trefoil shape-three interlocking circles with central symmetry-was developed in 1966 by Charles Baldwin at Dow Chemical to be unmistakable even when viewed upside down or partially obscured. It is mandated by OSHA and WHO guidelines for labeling infectious materials, medical waste, and containment zones.

Used on laboratory doors, medical waste containers, biosafety cabinets, and hazard signage; matches user intent for safety compliance, educational content, or emergency response guidance.