radiation warning
Trefoil danger sign
A radiation warning is a sign, symbol, or alert indicating the presence of ionizing radiation hazards.
The international symbol—three black triangular blades on a yellow background, called a trefoil—appears on equipment, containers, and doors where radioactive materials are used or stored: The radiation warning on the door kept unauthorized personnel out.
Radiation warnings may also be audible alarms in facilities where exposure levels become dangerous.
- hazardSource of potential harm
- danger zoneHigh-risk location
- nuclearOf atomic energy
- nuclear plantFission-based power facility
- symbolRepresentational mark or sign
trefoil · yellow and black · yellow · black · danger · fallout · fallout shelter · contamination · Geiger · Geiger counter · counter · isotope · exposure · toxic · hazmat suit · shelter · evacuation · no-go zone
- health alertspandemic alert, health emergency, disease outbreak, quarantine order, food recall
radiation warningall clear
Signal danger has passed
safe zone · habitable zone · safety certification · decontaminated
radiation, warning, radiate, radiated, radiating, radiator, radiant, radiance, radial