Danger vs Warning vs Caution: Which to Use
Updated: 5 hours ago
Walk any plant and you'll find DANGER on one breaker panel and CAUTION on the same hazard next door. Signal words tell workers how badly a hazard can hurt them. Here's what each one means, which colors go with it, and how to choose.
I've audited facilities where every sign in the building said DANGER. The intent was good. The result was a crew that tuned out all of them, including the ones on the 480-volt switchgear. Picking the right signal word is how you keep the serious warnings serious.
What OSHA's sign rule actually says
OSHA's accident prevention sign standard, 29 CFR 1910.145, sorts signs by use:
Danger signs. Employees must be instructed that danger signs "indicate immediate danger and that special precautions are necessary." The colors are red, black and white.
Caution signs. Used "only to warn against potential hazards or to caution against unsafe practices." The standard color is a yellow background with a black panel and yellow letters, and black lettering on the yellow.
Safety instruction signs. For general safety instructions and suggestions, with a white background and a green panel with white letters.
For accident prevention tags, the same section adds a middle level. Paragraph (f)(7) allows Warning tags "to represent a hazard level between 'Caution' and 'Danger.'" It also requires a tag's signal word to be readable from at least five feet, or farther if the hazard warrants it.
In 2013, OSHA updated its signage rules to reference the newer ANSI standards, ANSI Z535.1-2006(R2011), Z535.2-2011 and Z535.5-2011, alongside the older ones (78 FR 35559). That's why you'll see both OSHA-style and ANSI Z535-style signs on compliant job sites today.
How ANSI Z535 defines the four signal words
The ANSI Z535 series is the consensus standard most safety professionals reach for when they design signs and labels. According to ANSI's summary of Z535.2-2023, hazard alerting signs use three signal words, ranked by how likely an injury is and how bad it would be:
DANGER: a hazardous situation that, if not avoided, will result in death or serious injury. It's limited to the most extreme situations.
WARNING: a hazardous situation that, if not avoided, could result in death or serious injury.
CAUTION: a hazardous situation that, if not avoided, could result in minor or moderate injury.
NOTICE is the fourth word, and it isn't a hazard word at all. ANSI describes it as the usual choice for important information that isn't hazard-related, such as property damage, security, sanitation and housekeeping rules.
The colors are fixed, too. ANSI Z535.4 calls for white DANGER letters on safety red, black WARNING letters on safety orange, black CAUTION letters on safety yellow, and italic white NOTICE letters on safety blue, as In Compliance Magazine summarizes. DANGER, WARNING and CAUTION headers carry the safety alert symbol (the triangle with an exclamation point). NOTICE doesn't.
A quick way to choose
When I'm deciding on a sign at a piece of equipment, I ask two questions: If someone ignores this, how badly can they get hurt? and How likely is it?
DANGER
If ignoring it... Will kill or seriously injure
Typical examples: Exposed energized parts, confined space entry, toxic gas areas
WARNING
If ignoring it... Could kill or seriously injure
Typical examples: Pinch points, moving parts, automatic start-up
CAUTION
If ignoring it... Could cause minor or moderate injury
Typical examples: Slippery or uneven floors, low clearance, sharp edges
NOTICE
If ignoring it... Won't hurt anyone, but matters
Typical examples: PPE and access rules, housekeeping, security and policy messages
Three mistakes I see over and over:
DANGER everywhere. If a stack of pallets gets the same header as an arc flash hazard, people stop reading either one.
NOTICE used for a real hazard. A blue header tells people this isn't about injury. Don't put it on something that can cut a hand off.
Mixed formats on one machine. Pick OSHA-style or ANSI Z535-style for a line or an area and stick with it, so crews learn one visual system.
What each word looks like in practice
DANGER. Reserve it for hazards where contact means death or serious injury. Our DANGER High Voltage labels (5" x 10") are big enough to read from across an electrical room.
For confined spaces, toxic gases and other severe hazards, browse our full line of danger labels.
WARNING. This is the workhorse for machinery. The WARNING Pinch Point #2 labels are 3" x 5" and ANSI Z535-style, so they're ANSI compliant and OSHA compliant.
Moving parts, automatic start-up and rotating equipment often fall in this tier. See our warning labels for the full range.
CAUTION. Use it for hazards that hurt but don't usually kill. Our Caution Unsafe Surface labels (3.5" x 7") are ANSI Z535-style, ANSI compliant and OSHA compliant, and they suit icy entries, worn decking and uneven floors.
You'll find hot surfaces, sharp objects and door swing hazards among our caution labels.
NOTICE. Use it for rules and information. The NOTICE Hard Hat Required in This Area labels are OSHA-style 5" x 7" labels for area entrances.
PPE rules, drug-free workplace and surveillance notices are all in our notice labels.
Before you order
Walk the area with the people who work there. Rank each hazard, choose the signal word from the DANGER, WARNING, CAUTION and NOTICE definitions above, and replace any sign that's faded or contradicts its neighbor. Signs support guards, procedures and training; they don't replace them.
VLG labels are printed in house in Kenai, Alaska, on premium low-shrinkage calendered vinyl with an industrial strength adhesive, and they're Printed in the USA. If you're relabeling a full facility, we take bulk and custom orders. Minimums apply.
Start with your most serious hazards: shop our danger labels.
This article is general safety guidance, not legal advice. Sign and label requirements vary by industry, equipment and location, and State Plan states may differ. Check the current text of 29 CFR 1910.145, the ANSI Z535 standards and any equipment-specific rules, and consult a qualified safety professional about your site.
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