Didn’t You See the (Safety) Sign? Your Guide to OSHA’s Rules on Hazard Warnings

No matter how eye-catching a safety warning sign is—whether it has vivid color, gripping language, clear symbols or all three—it blends into the background after about 30 days.

Safety professionals have dubbed the phenomenon, caused by the human brain’s tendency to downplay familiar sights in favor of new sensory data, “sign blindness.”

It doesn’t happen only in workplaces. Drivers often become numb to street signs they pass routinely, which is how some receive tickets for failing to slow down in more restrictive speed zones that are part of their daily commutes.

Combating that tendency is a vital element of effective workplace safety signage, which begins with the basic elements of color, shape and letter-size detailed in OSHA Standard 1910.145 and an ANSI guideline incorporated by reference to some of its provisions.

The signs are “there for attention purposes, for training and they’re meant to be readily recognizable,” says Phil Zee, vice president for channel and content strategy at safety-sign maker AccuformNMC. “Visual acuity is critical.”

Along with requiring that signs be hung prominently, OSHA establishes colors to designate different types of messages: Red is used for danger signs, yellow for caution, orange for biohazards, gold for warning and green and white for safety instructions.

Danger, caution and instruction are OSHA’s three main classifications, each signaling different levels of risk to employees, Pete Nemmers, former director of training development for the National Association of Safety Professionals, says in a blog post on the organization’s website:

• Danger: Indicates immediate hazard that requires special precautions, such as high-voltage electrical current or toxic chemicals; has the potential to cause serious injury or death; should only be used for extremely high-risk conditions.
• Caution: Warns against possible dangers and unsafe practices, such as entering an area with hazardous chemicals without appropriate eye and ear protection; used in areas with the potential to cause mild to moderate injuries.
• Safety Instruction: Communicates general directions or procedures; might indicate an area restricted to authorized personnel, for example, or one where personal protective equipment can be picked up.

More narrowly targeted types of signs, Nemmers says, include:

• Notices: Convey non-safety information, such as identifying equipment that’s out of order.
• Biohazard warnings: Signal the presence of blood or other infectious materials. OSHA also requires labels on any containers, including refrigerators, used to ship or store such materials.
• Fire safety information: Identify fire exits and the locations of emergency firefighting equipment.

Following OSHA’s sign regulations—which also require that signs have rounded corners, be free of sharp edges, burrs and splinters and be hung securely—has benefits beyond simple compliance.

Doing so can also help insulate businesses from liability in case of an injury, Zee points out. “If an incident occurs, the employer, at minimum, can point to the sign to demonstrate that a hazard warning was given and unfortunately, the employee didn’t heed it.”

While OSHA allows use of pictographs as well as text, the message must be accurate and convey a clear direction, Nemmers says. Signal words, which communicate the most important message, must be readable from a safe distance, he adds. That varies by hazard but is always at least 5 feet away.

Supplementing Signs with Safety Training

The distance needed for workers to safely navigate a hazard directly influences how large both signs and their lettering should be, Zee explains. “Do you need to see and understand the sign 10 feet away, 20 feet away or 50 feet away?” he asks. “If you’ve got something that’s potentially explosive or very volatile, you probably want to be reading about it from as far away as possible.”

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ANSI guidelines spell out that signs should also convey information in the languages spoken by workers. In businesses with employees who don’t speak English fluently or have difficulty reading, pictographs and symbols can help overcome communication barriers.