OSHA Color Code Chart: Red, Yellow, and ANSI Z535 Additions

The OSHA color code chart comes down to this: red marks fire equipment, emergency stops, and immediate danger; yellow marks caution and physical hazards like tripping, striking, or falling; green marks safety equipment and first aid; and orange, blue, and purple carry meanings assigned by ANSI Z535 rather than by OSHA itself. Only red and yellow are mandated by OSHA for marking physical hazards on structures and equipment. The other colors most workplaces use are either sign-specific requirements under a separate OSHA rule or industry standards OSHA accepts as compliant.

Red and Yellow: The Only Colors OSHA Requires for Physical Hazards

29 CFR 1910.144 is short, and it covers just two colors. Everything else people call “the OSHA color code” comes from the sign regulation or from ANSI standards.

Red has three jobs under 1910.144:1Occupational Safety and Health Administration. 29 CFR 1910.144 – Safety Color Code for Marking Physical Hazards

  • Fire protection equipment. Fire alarm boxes, extinguishers, and fire exit signs must be red so workers can locate them fast.
  • Danger. Portable containers of flammable liquids with a flash point at or below 80°F must be painted red with yellow identification bands or lettering. Red lights also mark barricades and temporary obstructions.
  • Stop. Emergency stop bars on hazardous machines and stop buttons on electrical switches must be red.

Yellow is the required color for caution and for marking physical hazards where a worker could be struck, stumble, fall, trip, or get caught between moving parts.2eCFR. 29 CFR 1910.144 – Safety Color Code for Marking Physical Hazards Loading dock edges, stair nosings, low overhead beams, and guardrails around open pits are typical applications. The rule allows solid yellow, yellow-and-black stripes, or yellow-and-black checkers, whichever pattern draws the most attention in that setting.

Sign Colors Under 29 CFR 1910.145

The sign regulation defines three permanent-sign categories, each with its own color scheme:3Occupational Safety and Health Administration. 29 CFR 1910.145 – Specifications for Accident Prevention Signs and Tags

  • Danger signs use red, black, and white. The red oval header with white text signals the highest hazard level. Workers must be trained to treat a danger sign as immediate danger requiring special precautions.
  • Caution signs use a yellow background with a black panel and yellow letters, and black text on yellow for the message body. Workers must be trained that caution signs indicate a possible hazard.
  • Safety instruction signs use a green panel with white letters on a white background. These mark first aid kits, emergency eyewash stations, and similar safety equipment.

For tags attached to equipment or lockout devices, 1910.145 adds a warning tier that sits between danger and caution. Warning tags cover a hazard serious enough to exceed caution but below the immediately life-threatening level of a danger tag.

Orange, Blue, and Purple: The ANSI Z535 Additions

Most workplace signs use more colors than OSHA’s three categories cover. The extras come from the ANSI Z535 series, which OSHA references directly in 1910.145 for color specifications.3Occupational Safety and Health Administration. 29 CFR 1910.145 – Specifications for Accident Prevention Signs and Tags OSHA does not require ANSI Z535 formatting outright, but ANSI Z535.1 is incorporated by reference as an accepted color standard, and ANSI-formatted signs are widely treated as compliant.

The ANSI Z535 color meanings:

  • Red, danger. Immediate hazard likely to cause death or serious injury. Same as OSHA.
  • Orange, warning. A hazard that could cause death or serious injury, but at a lower probability than a danger-level hazard. This is the intermediate tier OSHA’s sign rule does not formally include for permanent signs.
  • Yellow, caution. A hazard that could cause minor or moderate injury.
  • Green, safety and first aid. Marks safety equipment and emergency stations.
  • Blue, notice. Non-hazard information such as company policies, equipment status, or general facility instructions.
  • Purple, radiation. Marks areas and containers with radioactive materials or X-ray equipment.

If your facility uses orange warning signs and blue notice signs, those come from ANSI Z535 rather than an OSHA regulation. They are considered best practice and accepted by OSHA inspectors, but the distinction matters when you are working out what is strictly required versus what is industry standard.

Biohazard Label Colors

Bloodborne pathogen labeling has its own mandatory color rule. Under 29 CFR 1910.1030, labels on containers of regulated waste, contaminated equipment, and refrigerators storing blood or other potentially infectious materials must be fluorescent orange or orange-red, with the biohazard symbol and text in a contrasting color.4Occupational Safety and Health Administration. 29 CFR 1910.1030 – Bloodborne Pathogens A red container can substitute for the fluorescent label, which is why red biohazard bags and sharps containers are so common in healthcare.5Occupational Safety and Health Administration. Biohazard Labeling – Standard Interpretation

What About Exit Signs?

Exit sign color is one of the most misunderstood parts of the OSHA color code. OSHA does not require exit signs to be a specific color. Under 29 CFR 1910.37, each exit sign must be “distinctive in color” and illuminated to at least five foot-candles by a reliable light source.6Occupational Safety and Health Administration. 29 CFR 1910.37 – Maintenance, Safeguards, and Operational Features for Exit Routes Whether the sign is red or green is a matter of local building and fire codes, not OSHA. Red is more common across most of the U.S., and green is standard in some jurisdictions and internationally.

Pipe Marking Colors

Industrial pipe systems follow a separate scheme under ASME/ANSI A13.1, which assigns background and text color combinations based on pipe contents. This is not an OSHA regulation, but OSHA can cite unmarked piping under the general duty clause, and A13.1 is the recognized industry standard. The main combinations:

  • Yellow background, black text: flammable or oxidizing fluids.
  • Red background, white text: fire-quenching fluids like water, foam, and CO₂ in sprinkler or fire-fighting systems.
  • Orange background, black text: toxic or corrosive fluids.
  • Brown background, white text: combustible fluids that can burn but are not classified as flammable.
  • Green background, white text: potable, cooling, and boiler feed water.
  • Blue background, white text: compressed air.

Label size scales with pipe diameter. Pipes under an inch need at least half-inch letter height; pipes over 10 inches in diameter need letters at least 3.5 inches tall. Pipes too small for a label get a permanently legible tag instead.

Penalties for Missing or Incorrect Color Coding

Color-coding and signage violations fall under OSHA’s general penalty schedule. As of the annual adjustment effective January 15, 2025, maximum penalties are:7Occupational Safety and Health Administration. 2025 Annual Adjustments to OSHA Civil Penalties

  • Serious violation: up to $16,550 per violation.
  • Other-than-serious violation: up to $16,550 per violation.
  • Willful or repeated violation: up to $165,514 per violation.
  • Failure to abate: up to $16,550 per day past the abatement deadline.

Missing or incorrect safety signs typically fall in the serious or other-than-serious range, with the classification depending on whether the violation creates a substantial probability of death or serious physical harm. A facility missing danger signs around a confined space entry is far more likely to draw a serious citation than one with a faded caution placard on a storage closet. Actual penalty amounts also factor in employer size, good-faith compliance efforts, and citation history, so smaller companies with clean records usually pay well below the maximums.