Safety signs: what each workplace sign means

Workplace safety signs are read by colour and shape before the picture. A green square shows a safe way or safety equipment, a red square shows fire equipment, a blue circle is something you must do, a red ring with a bar is something you must not do, and a yellow triangle warns of a hazard. The international set is ISO 7010, which prescribes safety signs for the purposes of accident prevention, fire protection, health hazard information and emergency evacuation ISO (International Organization for Standardization), ISO 7010:2019 Graphical symbols — Safety colours and safety signs — Registered safety signs, abstract of ISO 7010:2019 Each sign has a reference number, a letter for its class and three digits, such as E001 for an emergency exit.

Find it by colour and shape

Green square or rectangle, white symbol Safe condition: emergency exits, first aid, safety equipment
Red square or rectangle, white symbol Fire equipment: where the extinguisher, hose, alarm or fire phone is
Blue circle, white symbol Mandatory action: you must do this here
Red ring with a diagonal bar, black symbol on white Prohibition: do not do this here
Yellow triangle with a black border, black symbol Warning: a hazard is here

Green square or rectangle, white symbol: safe condition (E-series)

L64: rectangular or square shape; white pictogram on a green background (the green part to take up at least 50% of the area of the sign) Health and Safety Executive (HSE), L64 Safety signs and signals: The Health and Safety (Safety Signs and Signals) Regulations 1996. Guidance on Regulations (third edition), Part 2, emergency escape or first-aid signs, intrinsic features (b), page 17

Red square or rectangle, white symbol: fire equipment (F-series)

L64: rectangular or square shape; white pictogram on a red background (the red part to take up at least 50% of the area of the sign) Health and Safety Executive (HSE), L64 Safety signs and signals: The Health and Safety (Safety Signs and Signals) Regulations 1996. Guidance on Regulations (third edition), Part 2, firefighting signs, intrinsic features (b), page 18

Blue circle, white symbol: mandatory action (M-series)

L64: round shape; white pictogram on a blue background (the blue part to take up at least 50% of the area of the sign) Health and Safety Executive (HSE), L64 Safety signs and signals: The Health and Safety (Safety Signs and Signals) Regulations 1996. Guidance on Regulations (third edition), Part 2, mandatory signs, intrinsic features (b), page 16

Red ring with a diagonal bar, black symbol on white: prohibition (P-series)

L64: round shape; black pictogram on white background, red edging and diagonal line (the red part to take up at least 35% of the area of the sign) Health and Safety Executive (HSE), L64 Safety signs and signals: The Health and Safety (Safety Signs and Signals) Regulations 1996. Guidance on Regulations (third edition), Part 2, prohibitory signs, intrinsic features (b), page 14

Yellow triangle with a black border, black symbol: warning (W-series)

L64: triangular shape; black pictogram on a yellow background with black edging (the yellow part to take up at least 50% of the area of the sign) Health and Safety Executive (HSE), L64 Safety signs and signals: The Health and Safety (Safety Signs and Signals) Regulations 1996. Guidance on Regulations (third edition), Part 2, warning signs, intrinsic features (b), page 14

The colours, in HSE’s words

Colour and shape	ISO 7010 series	HSE L64 Table 1 and Table 3
Green square or rectangle, white symbol	E-series	Emergency escape, No danger, Doors; exits; escape routes; equipment and facilities, Return to normal
Red square or rectangle, white symbol	F-series	Firefighting equipment, Identification and location
Blue circle, white symbol	M-series	Mandatory sign, Specific behaviour or action, eg wear protective equipment
Red ring with a diagonal bar, black symbol on white	P-series	Prohibition sign, Dangerous behaviour; stop; shutdown; emergency cut-out devices; evacuate
Yellow triangle with a black border, black symbol	W-series	Warning sign, Be careful; take precautions; examine

These Regulations make it clear that safety signs are not a substitute for other means of controlling risks to employees; safety signs are to warn of any remaining significant risk or to instruct employees of the measures they should take in relation to these risks. Health and Safety Executive (HSE), L64 Safety signs and signals: The Health and Safety (Safety Signs and Signals) Regulations 1996. Guidance on Regulations (third edition), paragraph 16
Although these Regulations do not require safety signs to be used where there is no significant risk to health and safety, certain fire safety signs may have to be displayed under separate legal provisions. Health and Safety Executive (HSE), L64 Safety signs and signals: The Health and Safety (Safety Signs and Signals) Regulations 1996. Guidance on Regulations (third edition), paragraph 17
Pictograms used in signs should be as simple as possible and contain only necessary detail. BS EN ISO 7010 contains examples of varied signs which may be useful. Health and Safety Executive (HSE), L64 Safety signs and signals: The Health and Safety (Safety Signs and Signals) Regulations 1996. Guidance on Regulations (third edition), paragraph 44

In the US: danger, caution and safety instruction signs

OSHA sorts US signs into danger, caution and safety instruction signs, with colours from ANSI Z535.1. It does not use ISO 7010's five colour-and-shape classes, and it does not say which ISO class matches which of its own, so we do not match them up for it. ANSI Z535 itself is a paid standard and is not quoted here.

All employees shall be instructed that danger signs indicate immediate danger and that special precautions are necessary. US Occupational Safety and Health Administration (OSHA), 29 CFR 1910.145 Specifications for accident prevention signs and tags, 1910.145(c)(1)(ii)
Caution signs shall be used only to warn against potential hazards or to caution against unsafe practices. US Occupational Safety and Health Administration (OSHA), 29 CFR 1910.145 Specifications for accident prevention signs and tags, 1910.145(c)(2)(i)
Safety instruction signs shall be used where there is a need for general instructions and suggestions relative to safety measures. US Occupational Safety and Health Administration (OSHA), 29 CFR 1910.145 Specifications for accident prevention signs and tags, 1910.145(c)(3)
The standard color of the background shall be yellow; and the panel, black with yellow letters. US Occupational Safety and Health Administration (OSHA), 29 CFR 1910.145 Specifications for accident prevention signs and tags, 1910.145(d)(4), caution signs
The standard color of the background shall be white; and the panel, green with white letters. US Occupational Safety and Health Administration (OSHA), 29 CFR 1910.145 Specifications for accident prevention signs and tags, 1910.145(d)(6), safety instruction signs
The colors red, black, and white shall be those of opaque glossy samples as specified in Table 1, "Fundamental Specification of Safety Colors for CIE Standard Source 'C,' " of ANSI Z53.1-1967 or in Table 1, "Specification of the Safety Colors for CIE Illuminate C and the CIE 1931, 2 Standard Observer," of ANSI Z535.1-2006(R2011) US Occupational Safety and Health Administration (OSHA), 29 CFR 1910.145 Specifications for accident prevention signs and tags, 1910.145(d)(2), danger signs

What these pages cannot do

They cannot tell you which signs a workplace needs. In the UK that follows from the risk assessment, and fire signs from fire safety law; L64’s words on this are above.
They list 38 of the most common signs, not all of ISO 7010, which has several hundred and keeps adding more.
The drawings are simplified so the sign can be recognised; they are not for printing and putting up.

Sources

ISO 7010 is a paid standard. Its OBP entries are free to view, but they are a script-driven app, so the title and reference number above are copied from the entry's own heading as it lists them (read 2026-09-29), not from the paid text. Each sign’s own page links its ISO entry.

Health and Safety Executive (HSE): L64 Safety signs and signals: The Health and Safety (Safety Signs and Signals) Regulations 1996. Guidance on Regulations (third edition) (published 2015). Used here: Part 2, emergency escape or first-aid signs, intrinsic features (b), page 17; Part 2, firefighting signs, intrinsic features (b), page 18; Part 2, mandatory signs, intrinsic features (b), page 16; Part 2, prohibitory signs, intrinsic features (b), page 14; Part 2, warning signs, intrinsic features (b), page 14; Table 1, green, meaning or purpose (page 12); Table 3, red, meaning or purpose (page 26); Table 1, blue, meaning or purpose (page 12); Table 1, red, meaning or purpose (page 12); Table 1, yellow or amber, meaning or purpose (page 12); paragraph 16; paragraph 17; paragraph 44. www.hse.gov.uk Checked 2026-09-29.
ISO (International Organization for Standardization): ISO 7010:2019 Graphical symbols — Safety colours and safety signs — Registered safety signs (2019, with later amendments). Used here: abstract of ISO 7010:2019. www.iso.org Checked 2026-09-29.
US Occupational Safety and Health Administration (OSHA): 29 CFR 1910.145 Specifications for accident prevention signs and tags (current eCFR text). Used here: 1910.145(c)(1)(ii); 1910.145(c)(2)(i); 1910.145(c)(3); 1910.145(d)(4), caution signs; 1910.145(d)(6), safety instruction signs; 1910.145(d)(2), danger signs. www.osha.gov Checked 2026-09-29.