What color is typically used to indicate the presence of hazardous materials?

The presence of hazardous materials is commonly indicated by the color red. This color is universally recognized in various safety and emergency contexts to signal danger or risk, particularly in relation to flammable, explosive, or otherwise hazardous substances. Red signage and markings serve to alert individuals to take necessary precautions, ensuring they maintain a safe distance and observe safety protocols when in the vicinity of such materials.

In contrast, yellow often signifies caution, green typically indicates safety or go, and blue is used for information. While all these colors serve important roles in safety communications, red's association with hazard alerts makes it the standard for indicating hazardous materials.