DANGER, WARNING, CAUTION, NOTICE: which safety sign do you need?

The word at the top of a safety sign is called the signal word, and it is not a matter of taste. It tells a worker how serious the hazard is before they read another word. Use DANGER for everything and people stop paying attention to it. Use CAUTION for a lethal hazard and you have understated the risk. Here is how the categories line up.

What OSHA 1910.145 says

OSHA's rule for accident prevention signs is 29 CFR 1910.145. It classifies signs by the hazard they address and sets their colors:

• Danger signs are for places where an immediate hazard exists and special precautions are necessary. Red, black and white: a red upper panel, a black outline and a white lower panel.
• Caution signs warn against potential hazards or caution against unsafe practices. Yellow is the predominant color, with yellow lettering on a black panel and any other lettering in black.
• Safety instruction signs are for general instructions and suggestions about safety measures. White, with a green upper panel lettered in white and any other wording in black on the white background.

The rule also asks that wording be easy to read, concise and accurate, and that it make a positive suggestion rather than a negative one where possible. Separately, OSHA's safety color code in 29 CFR 1910.144 reserves red for fire protection equipment, danger and stop, and yellow for caution and for marking physical hazards.

Where WARNING and NOTICE come from

1910.145 does not define a WARNING sign or a NOTICE sign. Those signal words come from the ANSI Z535 family of standards, which grew out of the older ANSI Z35 standards that OSHA's sign rule was originally based on. OSHA has said that signs designed to the current ANSI Z535 standards are acceptable alternatives, so many employers now use the Z535 system throughout. (WARNING does appear in 1910.145 for tags, as a level between caution and danger.)

Under ANSI Z535, the signal words are defined by the outcome:

• DANGER: a hazardous situation that, if not avoided, will result in death or serious injury. White on red.
• WARNING: a hazardous situation that could result in death or serious injury. Black on orange.
• CAUTION: a hazardous situation that could result in minor or moderate injury. Black on yellow.
• NOTICE: information that is important but not related to personal injury, such as property damage or procedures. White on blue, with no safety alert symbol.
• Safety instruction signs, such as SAFETY FIRST, for safe practices and the location of safety equipment. White on green.

The triangle with an exclamation mark that appears beside DANGER, WARNING and CAUTION in Z535 is the safety alert symbol. It means there is a personal injury hazard, which is why NOTICE never carries it.

Picking one

Ask what happens if someone ignores the sign. If the answer is death or serious injury, and it will happen, use DANGER. If it could happen, WARNING. If the realistic outcome is a minor injury, CAUTION. If nobody gets hurt but something gets damaged or a procedure gets skipped, NOTICE. Then be consistent across the facility, so the same hazard always gets the same word.

Every header sign on this site has an OSHA layout and an ANSI layout; switch between them with the Style control. Start with a DANGER sign, a WARNING sign or a CAUTION sign, or browse the Sign Directory for ready-made messages.