Correctly using signs and colors for safety hazards

Ideally, the workplace would be free from hazards. In reality, some risks can’t be controlled, so the employer needs to mark or identify the hazard. Safety signs, labels, tags, placards, and other markings can inform workers of dangers and help prevent accidents and injuries.

For conveying a message quickly, color is just as important as the text. Ensuring consistency across hazard types and workplaces helps to better identify risk levels.

The OSHA regulations for signs and colors under 1910.144 and 1910.145 only mention a few colors. Generally, red means danger, yellow means caution, and green provides safety instructions. For additional colors, employers look to ANSI Z535.1, Safety Colors, which (among other things) adds blue for conveying safety instructions.

Choosing a color

Some OSHA standards include requirements on the color of safety signs and tags. If so, employers must use the colors specified. Where no color scheme is indicated, the employer must follow the color codes in 1910.145. Those colors and their meanings, along with some typical examples, include:

• Red for danger or emergency gear: Fire protection equipment, flammable liquid containers, emergency stop buttons, or high voltage.
• Yellow for caution: Wet floors, tripping hazards at elevation changes, or potential hazards, as well as traffic (watch for forklifts), flammable material storage, and corrosives.
• Orange for warning (a level between caution and danger): Machine parts that may cause injury, or exposed parts.
• Green for safety: First aid supplies, evacuation routes, and safety instructions.
• Blue for instructions: Safety information, PPE required, and notices (like authorized personnel only).
• Black and white: Traffic and housekeeping.
• Orange-red or fluorescent orange for biological hazards: Medical waste.

Confusion can arise where more than one color could be used. For example, an “eye protection required” sign could be blue or green (as an instruction) or yellow (as a caution). Similarly, an “authorized personnel only” sign might be blue for a restricted area with no hazards, but red for a high voltage area. Exit signs may be green or red. Machine guards do not require any color, though some employers paint them yellow.

Using tags

Where no sign or tag is specifically required, employers must determine if one is required anyway. Specifically, if the failure to designate hazards may cause injury or property damage, then signs or symbols must indicate and define those hazards.

Tags must be used to prevent injury or illness to employees who are exposed to hazardous or potentially hazardous conditions, equipment, or operations which are out of the ordinary, unexpected, or not readily apparent. Tags must be used until such time as the identified hazard is eliminated or the hazardous operation is completed. An example might be tagging a damaged ladder “do not use” as a warning.

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