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Safety Sign and Marking Requirements

Quick Tips #201


Employers have a responsibility to warn their employees about hazards that exist in the workplace. One of the easiest ways to accomplish this to follow established safety sign and marking requirements.

Two agencies govern safety signs and marking. The Occupational Safety and Health Administration (OSHA), which develops, implements and enforces standards, has specifications for safety signs, accident prevention signs and safety tags in 29 CFR 1910.145. These specifications apply to the design, application and use of signs or symbols used to prevent accidental injuries or property damage. These specifications do not cover plant bulletin boards, safety posters or any signs designed for streets, highways, railroads or marine regulations. The American National Standards Institute (ANSI) is a private organization which creates voluntary standards through consensus. Safety signs, accident prevention signs and safety tags are cited in Z535.1-2006(R2011), Z535.2-2011, Z535.4- 2011, Z535.5- 2011.

Sign Classification and Requirements

OSHA and ANSI classify safety signs according to use. Their definitions are very similar.

OSHA has three classifications of signs:

  1. Danger signs—Indicate immediate danger and that special precautions are necessary. OSHA also specifies that the red, black and white colors used for Danger signs be in accordance with ANSI Z53.1-1967.
  2. Caution signs—Warn against potential hazards or caution against unsafe practices. OSHA specifies that the standard color for Caution signs shall have a yellow background black panel and yellow letters. All letters used against the yellow background shall be black. The colors must be in accordance with ANSI Z53.1-1967.
  3. Safety instruction signs—Used where there is a need for general instructions and suggestions relative to safety measures. OSHA specifies that the standard color for Safety Instruction signs shall be a white background, green panel and white letters. Any letters used on the white background shall be black. The colors must be in accordance with ANSI Z53.1-1967.

Accident Prevention signs are classified by ANSI Z535.2- 2011 into eight classes:

  1. Danger—Indicate an immediately hazardous situation which, if not avoided, will result in death or serious injury. Danger is limited to the most extreme situations.
  2. Warning—Indicate a potentially hazardous situation which, if not avoided, could result in death or serious injury.
  3. Caution—Indicate a potentially hazardous situation which, if not avoided, may result in minor or moderate injury. Caution may also be used to alert against unsafe practices.
  4. Notice—Indicate a statement of company policy as the message relates directly or indirectly to the safety of personnel or protection of property.
  5. General safety—Indicate general instructions relative to safe work practices, reminders of proper safety procedures, and the location of safety equipment.
  6. Fire safety—Indicates the location of emergency fire fighting equipment.The other two classifications are directional arrow signs and special signs.

The other two classifications are directional arrow signs and special signs.

OSHA is not specific as to sign design for danger, caution, and safety instruction signs except for purpose and colors. When complying with OSHA regulations, it is important to check under the specific sign requirement with which you are trying to comply.

OSHA does require that signs be designed with rounded or blunt corners and must be free from sharp edges, burrs, splinters or other sharp projections. The ends or heads of fastening devices cannot be located as to create a hazard.

The size of the safety sign, height and width of the letters, and viewing distances are all defined by ANSI Z535.2-2011. OSHA does not have specifications like these for signs, and refers to the ANSI standard regarding these technicalities.

OSHA has specific requirements for the following:


29 CFR 1910.1003(e)(l)
29 CFR 1910.1027(m)
Electric Wiring
29 CFR 1910.306(c)(2)
29 CFR 1910.1045(p)
Bis-Chloromethyl ether
CFR 1910.1003(e)(l)
29 CFR 1910.1003(e)(l)
29 CFR 1910.1003(e)(l)
Coke oven emissions
CFR 1910.1029(l)
29 CFR 1910.37(b)
29 CFR 1910.1001(j)
Confined Space
Hazard Communications (Labels)
29 CFR 1910.1200(f)
29 CFR 1910.1028(j)
DBCP - 1,2-dibromo-3-chloropropane
29 CFR 1910.1044(o)
Ionizing Radiation
29 CFR 1910.1096(e)
29 CFR 1910.1003(e)(l)
3,3'-Dichlorobenzidine (and its salts)
29 CFR 1910.1003(e)(l)
29 CFR 1910.1025(m)
Biological Hazards
29 CFR 1910.145(e)(4)
4-Dimethylamino azobenzene
29 CFR 1910.1003(e)(l)
29 CFR 1910.68(c)(7)
Bloodborne Pathogens
29 CFR 1910.1030(g)(l)
Dip Tanks
29 CFR 1910.125(e)(5)
Methyl chloromethyl ether
29 CFR 1910.1003(e)(l)
29 CFR 1910.1003(e)(l)
beta Napthylamine
29 CFR 1910.1003(e)(l)
4 Nitrobiphenyl
29 CFR 1910.1003(e)(l)
29 CFR 1910.1003(e)(l)
Piping systems, Oxygen-fuel
29 CFR 1910.253(d)(4)
Spray finish
29 CFR 1910.107(g)(7)
Vehicles, slow-moving
29 CFR 1910.145(d)(10)
Vinyl Chloride
29 CFR 1910.1017(l)
4 beta-Propiolactone
29 CFR 1910.1003(e)(l)

Sign size

The wording on any safety sign should be concise and easy to read. The size of the lettering must be as large as possible for the intended viewing distance. Minimum letter height for the signal word (danger, caution, notice, etc.) shall be one unit of height for every 150 units of safe viewing distance. Minimum letter height for other words on the sign shall be one unit of height for every 300 units of safe viewing distance (ANSI Z535.2-2011).

Signal Word Letter Height (In.) Viewing Distance (Ft.)
5.00 62.50
4.50 56.25
4.00 50.00
3.50 43.75
3.00 37.50
2.50 31.25
2.00 25.00
1.50 18.75
1.00 12.50
0.75 9.375
0.50 6.25
0.25 3.125

Note: Crowding of letters reduces legibility.

Placement of Signs

ANSI rules for placement of safety signs are:

  1. Hazard alerting signs must be placed to alert and inform the viewer from a safe viewing distance.
  2. Safety and fire equipment signs must be clearly visible in the immediate vicinity of the equipment or do not create a distraction, and are not a hazard in themselves.
  3. Safety signs must be placed so that they are legible, do not create a distraction, and are not a hazard in themselves.
  4. Signs must not be placed on moveable objects or adjacent to moveable objects like doors, windows etc., which if moved, will obscure the sign.
  5. Environmental/facility safety signs should be placed in an protected area where there may be exposure to fading or damage.
  6. Where illumination may be necessary under emergency conditions, the signs should be equipped with emergency (battery operated) illumination or be reflective or both.

Safety color coding

OSHA has specific marking requirements for physical hazards in 29 CFR 1910.144:

  1. Red shall be the basic color used to mark:
    • Fire protection equipment and apparatus
    • Danger including safety cans or other portable containers of flammable liquids, excluding shipping containers. These shall be painted red with some additional clearly visible identification either in the form of a yellow band around the can or the name of the contents conspicuously stenciled or painted on the can (can should also be labeled in accordance with 1910.1200, Hazardous Communication /Global Harmonized System)
    • Stop, emergency stop bars, hazardous machines, stop buttons and other electrical switches used for emergency stopping
  2. Yellow shall be the basic color for designating caution and for marking physical hazards, such as striking against, stumbling, falling and getting caught in-between

ANSI standards for safety color coding are:

  1. Safety red identifies danger and stop.
  2. Safety orange identifies dangerous parts of machines or energized equipment.
  3. Safety yellow designates caution. Solid yellow, yellow and black stripes, or yellow and black checkers must be used for maximum contrast with the particular background.
  4. Safety green designates safety, emergency egress, and the location of first aid and safety equipment.
  5. Safety blue identifies safety information used on informational signs and bulletin boards.
  6. Safety purple is not yet assigned
  7. Safety gray is not yet assigned.
  8. Safety black, safety white, safety yellow or combinations of safety black with safety white or safety yellow are used to designate traffic or housekeeping markings.

Commonly Asked Questions

QWhich requirements should be followed, OSHA or ANSI? A Where OSHA has specific requirements, they must be followed. In the absence of OSHA requirements, ANSI standards should be followed. Any applicable federal, state or municipal regulations must also be followed.


29 CFR 1910.144, Safety Color Code for Marking Physical Hazards

29 CFR 1910.145, Specifications for Accident Prevention Signs and Tags

ANSI Z535.1-2011, Safety Color Code

ANSI Z535.2-2011, Environmental and Facility Safety Signs

ANSI Z535.3-2011, Criteria for Safety Symbols

ANSI Z535.4-2011, Product Safety Signs and Labels

(Rev. 6/2013)

Find even more information you can use to help make informed decisions about the regulatory issues you face in your workplace every day. View all Quick Tips Technical Resources at

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Please Note:
The content in this newsletter is intended for general information purposes only. This publication is not a substitute for review of the applicable government regulations and standards, and should not be construed as legal advice or opinion. Readers with specific compliance questions should refer to the cited regulation or consult with an attorney.

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