Safety signs in the U.S. follow a consistent system so people can judge the level of risk at a glance. The signal word at the top, and its color, tells you how serious the hazard is. The system most signs follow is the ANSI Z535 standard, and OSHA's sign rules (29 CFR 1910.145) use the same core ideas.
The signal words, from most to least serious
- DANGER (red): a hazard that will cause death or serious injury if not avoided. Reserve it for the most extreme situations, like high voltage or confined spaces. See electrical & high voltage stickers
- WARNING (orange): a hazard that could cause death or serious injury. Common for machinery, pinch points and chemical risks.
- CAUTION (yellow): a hazard that could cause minor or moderate injury, like wet floors, forklift traffic or low clearance. See slip, trip & general safety stickers
- NOTICE (blue): important information that isn't about personal injury, like "Authorized Personnel Only," "Video Surveillance In Use" or visitor check-in. See business & facility notices
- Safety instructions (green): general safe practices, first aid and emergency equipment locations.
How to pick the right one
Ask two questions: how bad is the worst realistic outcome, and how likely is it? If someone could be killed or seriously hurt, use DANGER or WARNING. If the realistic result is a bruise, sprain or cut, CAUTION fits. If nobody gets hurt but you need people to follow a rule, use NOTICE.
Avoid overusing DANGER. When every sign is red, people stop paying attention to the ones that matter most.
Outfitting a facility?
Our Warehouse Safety Kit covers the most common floor, dock and equipment warnings, and we offer bulk pricing on 25+ stickers.
This guide is a general overview, not a compliance review. Check the specific OSHA and ANSI requirements that apply to your workplace.