- Red are danger signs to inform to stop performing an action, to shut down, or to evacuate;
- Yellow or Amber are warning signs to inform potential hazards. Examples of yellow or amber signs are fire and explosion hazards, hot surfaces, trip hazards, and more.
- Blue are mandatory signs. It conveys information about a specific behavior or action, like requiring to wear protective equipment.
- Green are emergency escape or first-aid signs. It conveys information that first aid is available or it will take them on a safe route. Green signs are often used in emergency eye wash stations, evacuation routes, assembly points, and more.