A hazard is generally identified by a yellow sign with a black symbol or text, often in a triangular shape.

Core idea

Most modern safety standards use:

  • Yellow (or “safety yellow”) for caution and general hazards that could cause minor or moderate injury.
  • Red for immediate danger (risk of death or serious injury), fire-related hazards, and emergency stops.
  • Orange for particularly dangerous machine parts or serious mechanical hazards.

So when someone asks “what colour sign identifies a hazard?”, the usual answer in workplaces and on many road/Warning signs is yellow with black.

Quick nuances

  • Workplace and industrial standards (like OSHA/ANSI) associate hazard and caution with yellow, danger with red, and warning with orange.
  • Road warning signs in many countries also use a yellow or white background with a red border to signal a hazard ahead.

In short: yellow-and-black generally signals a hazard, while red signals immediate danger, and orange highlights especially dangerous machine parts.

Information gathered from public forums or data available on the internet and portrayed here.