Corrosive Signs: OSHA and IFC Rules and Where to Post Them

Last Updated: 2026-10-29

Answer Capsule: A corrosive sign is an OSHA accident prevention sign under 29 CFR 1910.145, posted in DANGER, WARNING or CAUTION format where acids and caustics are stored or used. OSHA 1910.151(c) requires eyewash and shower facilities in those areas, and IFC Chapter 54 requires NFPA 704 hazard identification per Section 5003.5. The corrosive sign supplements the NFPA placard.

A pool operator calls Print Pro AZ after a fire inspection. The chemical room has a fresh NFPA 704 diamond on the door, but the inspector wrote up two more items: no corrosive sign at the muriatic acid storage and no eyewash marked within reach. The diamond was right. It was not enough on its own.

That is the most common miss with corrosive materials. The fire marshal wants the NFPA 704 placard, OSHA wants the accident prevention sign and the eyewash, and each one comes from a different rule. Miss any of them and you get a re-inspection.

This guide covers the corrosive sign from all three angles: the OSHA 1910.145 sign formats, the 1910.151(c) eyewash rule, and IFC Chapter 54 storage requirements. Brent Hanke at Print Pro AZ has printed corrosive signs for plating shops, labs, water plants and pool contractors, and the placement question is always the same.

What Is a Corrosive Sign and When Does OSHA Require It?

A corrosive sign is a warning sign that tells workers a material in the area can burn skin, eyes or metal on contact. OSHA does not have a rule that says "post a corrosive sign," but it has two rules that get you there.

First, 29 CFR 1910.145 covers accident prevention signs and tags. It says signs must be posted to warn of specific hazards that can lead to injury, and it sets the DANGER, WARNING and CAUTION formats. If corrosives create a hazard in your workplace, this is the rule an OSHA inspector cites for a missing or wrong sign.

Second, 29 CFR 1910.1200, the Hazard Communication Standard, requires you to tell employees about the chemical hazards they work with. Together, these two rules make a corrosive sign expected wherever you store or use acids and caustics in quantity.

The common corrosives from the Print Pro AZ 50-chemical table all rate 3 on the blue health square: sulfuric acid 3-0-2 with W, hydrochloric acid 3-0-0, sodium hydroxide 3-0-1, and potassium hydroxide 3-0-1. Each one belongs behind a corrosive sign. The full NFPA 704 rating system is explained in the pillar guide to how to read the NFPA 704 diamond.

Which Sign Format Does OSHA 1910.145 Require: Danger, Warning or Caution?

OSHA 1910.145 uses three signal words, and the one you pick depends on how severe and how likely the injury is. The design rules follow the ANSI Z535 standard, which is why current signs use a header panel, a safety alert triangle and a message panel.

Signal word	Header colors	Use it when
DANGER	White letters on red, black panel	Immediate hazard that will cause death or serious injury. Concentrated acids, caustic tanks, plating baths.
WARNING	Black letters on orange	Hazard that could cause death or serious injury. Most corrosive storage rooms.
CAUTION	Black letters on yellow	Hazard that could cause minor or moderate injury. Dilute solutions, small containers.

Under 1910.145, DANGER signs are for situations where an immediate hazard exists, and CAUTION signs warn against potential hazards or unsafe practices. Print Pro AZ prints all three formats in the OSHA danger signs collection, with the corrosive pictogram and your wording.

Callout: The sign wording must be short, positive and easy to read. "DANGER, Corrosive, Wear Eye and Face Protection" works. A paragraph of text does not. Match the letter height to the viewing distance.

What Does OSHA 1910.151(c) Require for Eyewash and Showers?

OSHA 29 CFR 1910.151(c) requires suitable facilities for quick drenching or flushing of the eyes and body wherever a person may be exposed to injurious corrosive materials. The facilities must be within the work area for immediate emergency use.

The rule itself does not give distances or flow rates. Inspectors and most AHJs lean on the ANSI Z358.1 emergency equipment standard for those, which puts the station within a ten-second walk on the same level with no obstructions. Confirm what your AHJ expects, because it varies by city.

What the sign side of this looks like:

• An EMERGENCY EYEWASH or EMERGENCY SHOWER sign at the station, visible over racks and drums
• A clear path marked or kept open from the corrosive storage to the station
• The corrosive sign near the storage pointing the way, such as "Eyewash Station 20 Feet"

Print Pro AZ prints eyewash and shower signs alongside corrosive signs so the set arrives together.

What Does IFC Chapter 54 Require for Corrosive Storage?

IFC Chapter 54 covers the storage, use and handling of corrosive materials, and it points back to the general hazardous materials provisions in Chapter 50 for hazard identification. That means the NFPA 704 placard requirement in Section 5003.5 applies to your corrosive room.

IFC 5003.5 requires hazard identification signs as specified in NFPA 704 on stationary containers and above-ground tanks, and at entrances to locations where hazardous materials are stored, dispensed, used or handled in quantities requiring a permit. The fire marshal can require placards below those amounts.

The IFC also requires No Smoking signs in rooms where hazardous materials are stored or used in permit quantities, under Section 5003.7.1. So a corrosive room with a permit quantity of acid needs at least three signs: the NFPA 704 diamond, the corrosive warning, and No Smoking. Add the eyewash sign from OSHA and you have the core set. The rest of the checklist is in chemical storage room signs inspectors look for.

Where Does the Corrosive Sign Go Relative to the NFPA 704 Placard?

The NFPA 704 diamond goes at the entrance, and the corrosive sign goes beside it or at the specific storage location inside. The diamond is for the firefighter outside; the corrosive sign is for the worker about to open the door or the drum.

A layout that passes inspection at a typical corrosive room:

1. NFPA 704 diamond on the door or beside it, at eye level or above the door, clear of the door swing, visible by flashlight. It carries the composite room rating, the highest number in each color from any material inside, plus any special symbols.
2. Corrosive sign next to the diamond, in DANGER or WARNING format, so the person reaching for the handle sees both at once.
3. Corrosive sign at the storage rack or tank inside, where the drums actually sit, with the PPE required.
4. Eyewash sign at the station, with a directional sign if it is out of sight.
5. No Smoking sign at the entrance.

One rule that trips people up: do not write COR inside the white square of the NFPA diamond. NFPA 704 authorizes only W with a line through it, OX and SA there; COR, ACID and ALK are not part of the standard. NFPA 704 says to place them outside the diamond, and a strict fire marshal can call them non-compliant inside it. The separate corrosive sign is the right way to say it.

What Material Should a Corrosive Sign Be Made Of?

Use vinyl indoors and aluminum outdoors. Acid vapor and Arizona sun are hard on signs, so the material matters more here than for a parking sign.

Inside, a vinyl label on the cabinet or door holds up well and is easy to replace when the inventory changes. Outside, at a bulk caustic tank or an exterior acid storage cage, .040 rust-free aluminum keeps its color through years of UV. Vinyl in direct sun fades within a season.

Size the sign to the viewing distance: small on a cabinet, and readable from the same distance as the NFPA 704 diamond next to it on an exterior tank. Print Pro AZ prints corrosive, flammable, no smoking and chemical storage signs on request through the custom sign zone.

Partner companies that post the full sign set before the inspection report 45%+ better first-time inspection pass rates. The free NFPA 704 Diamond Field Guide lists ratings for 50 common chemicals, use the download form on this page to get it.

Frequently Asked Questions

Is a corrosive sign required by OSHA?

Not by name, but 29 CFR 1910.145 requires accident prevention signs wherever a specific hazard can cause injury, and 1910.1200 requires you to communicate chemical hazards to employees. Together they make a corrosive sign expected at any acid or caustic storage area.

Can I put COR in the white square of the NFPA diamond?

No. NFPA 704 authorizes only W with a line through it, OX and SA in the white square. COR, ACID and ALK are not part of the standard. Post a separate corrosive sign next to the diamond instead.

How close does the eyewash need to be to corrosive storage?

OSHA 1910.151(c) requires it within the work area for immediate use but gives no distance. Most inspectors apply the ANSI Z358.1 guidance of a ten-second travel time on the same level, with the path unobstructed. Check with your AHJ.

Do I need a corrosive sign for pool chemicals?

Check the SDS. Muriatic acid, which is hydrochloric acid rated 3-0-0, is corrosive and needs the sign. Pool chemical rooms also commonly hold oxidizers like calcium hypochlorite, so the NFPA 704 diamond on the door needs the OX symbol along with the corrosive warning.

Conclusion

A corrosive sign is an OSHA accident prevention sign under 29 CFR 1910.145, in DANGER, WARNING or CAUTION format, posted where acids and caustics are stored or used. OSHA 1910.151(c) requires an eyewash or shower within the work area, and IFC Chapter 54 sends you to Section 5003.5 for the NFPA 704 placard at the door. The corrosive sign supplements the diamond and never replaces it.

Posting the full set before the inspector arrives saves you a re-trip and keeps your crew's eyes out of the flush station. Shop the OSHA danger signs collection for corrosive and eyewash signs, or call Brent at (602) 649-5305 with your chemical list.

Sources

• OSHA 29 CFR 1910.145, Specifications for Accident Prevention Signs and Tags
• OSHA 29 CFR 1910.151, Medical Services and First Aid
• 2021 International Fire Code

Brent Hanke | Print Pro AZ | (602) 649-5305 | b.hanke@printproaz.com

Brent Hanke is the founder of Print Pro AZ, supplying NEC-compliant labels to contractors across the country.