August 27, 2026 Steven Eaton

Custom Safety Signs: A Ten-Step Design Checklist (2026 Guide)

Can you write your own safety sign?

Short answer: Yes, and most facilities have to — catalogue signs never cover the specific hazards a real building contains. But custom wording does not create a custom exemption. A sign you wrote still owes the same duties as one you bought: the right class under 1910.145(c), the specified colours under (d), rounded or blunt corners and no sharp edges, burrs or splinters under (d)(1), and wording that is concise, easily understood, positive rather than negative, and accurate in fact under (e)(2). The most common defect in custom signage is a single one: DANGER used on a hazard that is merely potential.

Published August 27, 2026

Custom signage is where a facility's signage programme either becomes genuinely useful or quietly falls apart. A sign written by someone who knows the hazard beats a generic one from a catalogue every time. A sign written by whoever had the label printer open, at the moment they were annoyed about something, is how a building ends up with nine DANGER signs on hazards that will not hurt anybody — after which nobody reads the tenth.

This guide is a design checklist. Work through it in order for any sign you are about to make, and the output will withstand both an inspection and, more importantly, the people who have to read it every day. It sits under the OSHA safety sign requirements hub.

Why this matters.
Signal words are a shared currency, and a facility can debase its own. Every DANGER sign placed on a hazard that will not kill teaches the workforce that DANGER is a figure of speech. The cost is not paid at the sign you got wrong — it is paid at the one you got right, in front of the hazard that really would have killed someone, by a worker who has learned that the red header here means "management is irritated." Signal-word discipline is not pedantry. It is the maintenance of the only vocabulary you have for the worst day.

Step 1 — Should this be a sign at all?

Before designing anything, check that a sign is the right instrument. OSHA's own tag rule states the principle plainly at 1910.145(f)(3): tags are not required where signs, guarding or other positive protection is being used. The same logic runs upward. A sign is a warning, and warnings sit at the bottom of the hazard-control hierarchy.

Can the hazard be eliminated or guarded? Then do that. A sign in place of a guard is both an ineffective control and written evidence that the hazard was recognised.
Is the hazard permanent or temporary? Permanent hazards get signs; temporary or unexpected ones get tags, which is the whole basis of the split in accident prevention tags.
Is this a hazard warning or a facility instruction? "Do not prop this door" is housekeeping, not a hazard. Giving it a CAUTION header spends signal-word credibility on a rule.
Does a sign already cover it? Two signs saying similar things in one sightline dilute each other. Adding is easy; the discipline is in removing.

Step 2 — Pick the class, and know that OSHA has only three

1910.145(c) recognises exactly three sign classes, and the wording of each defines its trigger:

Class	Trigger	Colours under (d)
Danger — (c)(1)	Indicates immediate danger and that special precautions are necessary	(d)(2) — red, black and white
Caution — (c)(2)	Warns against potential hazards or cautions against unsafe practices	(d)(4) — yellow background with a black panel and yellow letters
Safety instruction — (c)(3)	Where there is a need for general instructions and suggestions relative to safety measures	(d)(6) — white background with a green panel and white letters

There is no OSHA "Warning" sign class. This trips up nearly everyone, because WARNING exists as an ANSI Z535 signal word, and it exists as an OSHA tag class at 1910.145(f)(7). It does not exist as an OSHA sign class. A facility running OSHA-format signage has three headers; a facility running ANSI-format signage has four. Both are lawful — the two compliance routes are set out in OSHA vs ANSI safety signs — but a custom sign has to be built to one system, not to a blend of both.

Note also what (d) names: the colours are specified by reference to ANSI Z53.1-1967 or ANSI Z535.1-2006(R2011). Those are the editions OSHA cites, not the current ones. And a colour worth getting right because vendors get it wrong: green is the safety-instruction colour, and NOTICE in the ANSI system is white italic text on blue — not green.

Step 3 — The severity test that prevents the most common defect

Read the two triggers again and notice what separates them. Danger is for immediate danger. Caution is for potential hazards. The distinction is not how bad the outcome would be — it is how certain the harm is if the hazard is not avoided.

So the test for a custom sign is a single question: if a person ignores this sign, will they be seriously hurt, or might they be?

Will be, and seriously — exposed 480-volt busbar behind an open cover, an unguarded point of operation, an unprotected fall edge. That is DANGER.
Might be, or the injury is lesser — a low header, a floor that becomes slippery when wet, a hot surface that will burn but not maim. That is CAUTION in the OSHA system, and it is where the ANSI system's extra WARNING level earns its keep.
Neither — it is a rule or an instruction — PPE required beyond this point, authorised personnel only, report all damage. That is a safety instruction sign.

Placing DANGER on a merely potential hazard is the single most common defect in custom signage, and it is self-inflicted damage to the sign set. The full signal-word logic, including where NOTICE fits, is in danger vs warning vs caution signs.

Step 4 — Write the wording against 1910.145(e)(2)

The wording clause is short and every phrase in it is a test a custom sign can fail. The sign wording should be easily read and concise, should contain sufficient information to be easily understood, should make a positive rather than a negative suggestion, and should be accurate in fact.

Easily read and concise. A sign is read in about two seconds by someone already walking. Long copy is not thoroughness; it is a message that will not be received. If it needs a paragraph, it is a procedure and belongs in a procedure.

Sufficient information to be easily understood. The counterweight to concise. "DANGER" alone is not a sign — the reader has to know what the hazard is and what to do. Name the hazard specifically: "high voltage" beats "electrical hazard"; "automatic start" beats "moving parts."

Positive rather than negative. The clause most often overlooked and the one that most improves a sign. Tell people what to do, not only what not to do. "Use the walkway" outperforms "Do not walk here," because a prohibition without an alternative leaves the reader with a problem and no solution. Where a prohibition is genuinely the message — do not enter, do not operate — keep it, but pair it with the condition under which entry or operation is allowed.

Accurate in fact. This is the clause with teeth, and custom signs fail it constantly, usually by ageing into inaccuracy. A sign naming a hazard removed two years ago is inaccurate. A sign naming a PPE requirement the site no longer enforces is inaccurate. A sign citing a standard paragraph that has since been renumbered is inaccurate. Every one of those is a codified failure, not a tidiness issue — and each one teaches readers that the signs here describe a building that no longer exists.

Step 5 — Build it to survive: the physical clause people forget

1910.145(d)(1) is a construction requirement, and it applies to a sign you made exactly as it applies to one you bought. Signs must have rounded or blunt corners and be free from sharp edges, burrs and splinters, and the fastening devices must be arranged so they do not themselves present a hazard.

This is precisely where home-made signage fails, because the usual custom sign is a sheet of aluminium or acrylic cut to size in the maintenance shop. Square corners at head height in a corridor are a laceration hazard created by a safety sign. Round the corners, deburr the edges, and use fasteners that sit flush.

Then specify for the environment, which no standard dictates but every failed sign proves: UV for outdoors, chemical resistance for wash-down and solvent areas, temperature range for freezers and hot work. A sign that has faded to unreadable has failed the easily-read test at (e)(2) as surely as one that was never legible.

Step 6 — Size it for the distance it will be read from

OSHA sets no general letter height for facility signs. It sets one for exit signs — 6-inch letters with three-quarter-inch strokes under 1910.37(b)(7), covered in exit sign requirements — and it sets one for tags, which must be legible at a minimum of five feet under 1910.145(f)(4). Neither generalises to a wall sign.

So the size test is functional, and it should be applied physically rather than on screen. Decide the distance at which the reader must have understood the message — which is not where the hazard is, but where they still have room to act on it — then stand at that distance and read a printed proof. A pinch-point label read at arm's length and a forklift-traffic sign read at forty feet are different objects, and designing both at the same size guarantees one of them is wrong.

Step 7 — Place it where the decision is made

Placement is content. A sign belongs where the reader still has the option to change what they are doing:

At the decision point, not the hazard. A PPE-required sign at the door, not beside the machine, because the door is where a person can still go back for their glasses.
In the sightline of the approach. Walk every route a person can take to the hazard, including the one through the back. Signs get mounted where the ladder was, and the ladder is rarely on the approach.
Not where it can be obscured. Signage in a warehouse competes with racking, stacked stock and seasonal decoration — and obscuring an exit door is a finding under 1910.37(b)(3) in its own right.
Not in a cluster. A wall carrying six signs communicates none of them. If a doorway genuinely needs six messages, it needs one well-designed sign that carries them in priority order.

The custom sign checklist

Confirm a sign is the right control. The hazard cannot reasonably be eliminated or guarded, it is permanent rather than temporary, and no existing sign already covers it.
Assign the class from the trigger wording, not from how you feel about the hazard. Immediate danger requiring special precautions is DANGER; a potential hazard or unsafe practice is CAUTION; general instruction is a safety instruction sign. Remember there is no OSHA Warning sign class.
Apply the specified colours for that class — red/black/white for danger, yellow ground with black panel and yellow letters for caution, white ground with green panel and white letters for safety instruction — and stay inside one system, OSHA-format or ANSI-format, across the whole site.
Write the message to (e)(2): concise, sufficient, positive, accurate. Name the specific hazard, give an instruction the reader can act on where they are standing, and state the condition under which the prohibited thing becomes allowed.
Add a symbol if one exists for the hazard. It carries the message to readers who cannot read the text at all — see bilingual safety signs for when symbols beat translation.
Size it by proofing at the real reading distance, standing where the reader must have understood the message and still have room to act.
Build to (d)(1): rounded or blunt corners, no sharp edges, burrs or splinters, non-hazardous fastenings, in a substrate specified for the actual environment.
Place it at the decision point, in the sightline of every approach, unobscured and uncluttered — then walk each approach to confirm it rather than assuming.
Log it. Location, class, wording, date, author, and the hazard it addresses. This is what makes the sign reviewable, and it is what lets you find and retire it when the hazard goes away.
Put it on the review cycle. A custom sign is accurate on the day it is made and drifts from then on. The accuracy clause at (e)(2) is a live obligation, not a one-time test.

Frequently asked questions about custom safety signs

Can we make our own safety signs?

Yes. Nothing requires signs to be purchased, and custom signs are usually better because catalogue stock cannot describe a specific hazard. Custom wording does not create a custom exemption: the sign still owes the class, colour, construction and wording duties in 1910.145, and the physical requirements at (d)(1) are where home-made signs most often fail.

What are the three OSHA sign classes?

Danger signs at 1910.145(c)(1), for immediate danger where special precautions are necessary; caution signs at (c)(2), warning against potential hazards or unsafe practices; and safety instruction signs at (c)(3), where general instructions and suggestions relative to safety measures are needed. There is no OSHA Warning sign class.

Why is there no OSHA Warning sign?

OSHA's sign scheme predates the ANSI Z535 series and was built with three classes. WARNING exists as an ANSI Z535 signal word, and it exists as an OSHA tag class at 1910.145(f)(7), but not as an OSHA sign class. A facility can lawfully run four signal words by using the ANSI format — it just should not mix the two systems on one sign face.

When should a custom sign say DANGER instead of CAUTION?

When the harm is immediate and serious rather than potential. The test is certainty, not severity: if ignoring the sign means a person will be seriously hurt, it is DANGER; if they might be, or the injury is lesser, it is CAUTION. Using DANGER on a merely potential hazard is the most common custom-signage defect and it devalues every genuine DANGER on site.

What does OSHA require a sign to say?

Under 1910.145(e)(2), wording should be easily read and concise, contain sufficient information to be easily understood, make a positive rather than a negative suggestion, and be accurate in fact. The accuracy requirement is the one custom signs most often fail over time, as hazards are removed and the signs describing them stay up.

Do safety signs need rounded corners?

Yes. 1910.145(d)(1) requires signs to have rounded or blunt corners and to be free from sharp edges, burrs and splinters, with fastening devices arranged so they do not present a hazard. This applies to a sign you fabricated exactly as to one you bought, and square-cut aluminium at head height in a corridor is a hazard created by a safety sign.

What colours must a custom sign use?

Red, black and white for danger signs under (d)(2); a yellow background with a black panel and yellow letters for caution signs under (d)(4); and a white background with a green panel and white letters for safety instruction signs under (d)(6). The colours are specified by reference to ANSI Z53.1-1967 or ANSI Z535.1-2006(R2011) — the editions OSHA names, not the current ones.

Is green a NOTICE colour?

No, and this is a vendor error worth watching for. Green is the safety-instruction colour in OSHA's scheme. In the ANSI system, NOTICE is white italic text on a blue panel, and the safety alert symbol is never used with NOTICE because NOTICE addresses practices not related to personal injury.

How big do the letters on a custom sign need to be?

OSHA sets no general letter height for facility signs. It sets one for exit signs — 6-inch letters with three-quarter-inch strokes under 1910.37(b)(7) — and requires tags to be legible at a minimum of five feet under 1910.145(f)(4). For everything else the test is functional: proof the sign and read it from the distance at which a person must have understood it and can still act.

Can a custom sign cite an OSHA standard number?

It can, and it usually should not. Citations add length to a message read in two seconds, and they age — a renumbered or superseded paragraph on a sign becomes inaccurate wording under (e)(2). Keep the regulatory reference in the written signage programme, where it can be maintained, rather than on the sign face.

Should custom signs include a symbol?

Where a conventional symbol exists for the hazard, yes. Symbols carry the message to readers who cannot read the text at all, and they survive a change in workforce language. Reserve text for the conditional and procedural parts a symbol cannot express, and do not invent a symbol — an unconventional pictogram is understood only by whoever drew it.

How many signs are too many?

The practical limit is reached when a reader stops reading, which happens well before the wall is full. Clusters of signs at one doorway compete with each other and none of them lands. If a location genuinely carries several messages, one well-designed sign presenting them in priority order beats six competing ones.

Who should approve a custom sign?

Whoever owns the signage programme, rather than whoever noticed the hazard. The value of a single approval point is consistency: one signal-word vocabulary, one colour system, one format across the site. Sites that let any supervisor print a sign accumulate contradictory headers within a year.

How often should custom signs be reviewed?

On a fixed cycle and whenever the hazard changes, because the accuracy duty at (e)(2) is continuous. The specific thing to look for is signs that have outlived their hazard — they are the ones that teach readers the signs here can be ignored, which costs far more than the sign that is merely faded.

Can a sign replace a machine guard?

No. Guarding is an engineering control required in its own right, and a warning sits at the bottom of the control hierarchy. A sign in place of a guard is an ineffective control and documentary evidence that the hazard was recognised and not engineered out. Signs address residual risk after guarding, never instead of it.

Do custom signs need to match the ANSI format?

No. Both the OSHA legacy format and the ANSI Z535 format are lawful routes, and OSHA's 2013 signage rule made the ANSI editions it names an alternative rather than a replacement. What matters is that a site commits to one system and applies it consistently, so that a header means the same thing everywhere in the building.