What color must biohazard warning labels be printed on?

Biohazard warning labels must be printed on a fluorescent red-orange background to ensure they are easily recognizable and convey the appropriate level of hazard. The bright coloration is critical for drawing immediate attention to the potential dangers presented by biohazardous materials. This specific color has been standardized and is widely recognized internationally, making it an important aspect of safety protocols in environments where biological hazards may be present.

The distinction of using fluorescent red-orange over other colors like red, blue, or yellow lies in its visibility. While red is often associated with warnings, its effectiveness increases significantly when paired with the fluorescent quality, which enhances visibility in various lighting conditions. Therefore, the use of fluorescent red-orange effectively communicates the urgency of caution required when dealing with biohazards.