ISO 7010 · W-series · Warning

W023 Warning; Corrosive substance

Our drawing, not ISO’s artwork.

A corrosive substance, one that can burn skin or eat into metal, is stored or used here.

ISO 7010 reference: W023
Registered title: Warning; Corrosive substance ISO Online Browsing Platform, ISO 7010 - W023, Warning; Corrosive substance, reference number and registered title
Colour and shape: Yellow triangle with a black border, black symbol: Warning: a hazard is here

What the yellow triangle with a black border means

In HSE’s guidance on the UK Safety Signs and Signals Regulations 1996, a warning sign has a triangular shape 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 (a), page 14 and a 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

Its colour stands for: Warning sign, Be careful; take precautions; examine 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), Table 1, yellow or amber, meaning or purpose (page 12)

In the UK: HSE L64

Corrosive material 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), name under the warning signs in Schedule 1, page 15

In the US: OSHA

OSHA’s rule below is about the hazard or the equipment, not about the sign itself.

Where the eyes or body of any person may be exposed to injurious corrosive materials, suitable facilities for quick drenching or flushing of the eyes and body shall be provided within the work area for immediate emergency use. US Occupational Safety and Health Administration (OSHA), 29 CFR 1910.151 Medical services and first aid, 1910.151(c)

Signs people confuse with it, or find beside it

Other warning signs

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. Other lines in quotation marks are HSE’s or OSHA’s words.

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: name under the warning signs in Schedule 1, page 15; paragraph 63; Part 2, warning signs, intrinsic features (a), page 14; Part 2, warning signs, intrinsic features (b), page 14; Table 1, yellow or amber, instruction and information (page 12); Table 1, yellow or amber, meaning or purpose (page 12). www.hse.gov.uk Checked 2026-09-29.
US Occupational Safety and Health Administration (OSHA): 29 CFR 1910.151 Medical services and first aid (current eCFR text). Used here: 1910.151(c). www.osha.gov Checked 2026-09-29.
ISO Online Browsing Platform: ISO 7010 - W023, Warning; Corrosive substance (registered safety sign entry). Used here: reference number and registered title. www.iso.org Checked 2026-09-29.