Fire extinguisher colours and letters: what each one means

In the UK every extinguisher body is red; a band of colour on it names what is inside. The letters on the label name the kinds of fire it has been rated for, and the UK and US letters do not match: C is a gas fire in the UK and an electrical fire in the US.

First: raise the alarm, get out, call the fire service

UK: However, if in doubt, employees should not put themselves or anyone else at risk, but simply raise the alarm, leave the premises, and call the fire and rescue service. HM Government (GOV.UK), A guide to making your small non-domestic premises safe from fire (accessible version), section ‘Fire extinguishers’

US: If you're unsure about whether it is safe to use a fire extinguisher, and for all other situations, alert others, leave the building, and call 911 from a mobile or neighbor's phone. US Fire Administration (FEMA), Choosing and Using Fire Extinguishers, ‘Help people decide when to use a fire extinguisher’

Find it by what you see

The colour on the body

The letter on the label: UK and Europe

The letter on the label: United States

The colour key

The body colour of fire extinguishers is signal red, irrespective of the extinguishing media they contain. London Fire Brigade (London Fire Commissioner), Fire Safety Guidance Note GN08: Hand Held Portable Firefighting Equipment, Rev 20, §4.1
In the United Kingdom a colour zone of up to a maximum of 5% of the surface area of the extinguisher body may be used to identify the extinguishing agent. London Fire Brigade (London Fire Commissioner), Fire Safety Guidance Note GN08: Hand Held Portable Firefighting Equipment, Rev 20, §4.3
Certain companies and other premises types may have extinguishers that co-ordinate to their specific ‘Brand’ or have less conspicuous colours. These may still have the 5% surface area in colour, as detailed in paragraph 4.3 below. London Fire Brigade (London Fire Commissioner), Fire Safety Guidance Note GN08: Hand Held Portable Firefighting Equipment, Rev 20, §4.2
The contents of an extinguisher is indicated by a zone of colour on the red body. HM Government (GOV.UK), Fire safety risk assessment: offices and shops (accessible version), Part 1, 3.4.2, Figure 8

Colour	Agent	UK/EU classes named for it	US classes
Red all over	Water	Class A	Class A
Cream band	Foam	Class A, Class B	Class A, Class B
Blue band	Dry powder (ABC)	Class A, Class B, Class C, Electrical	Class A, Class B, Class C
Signal violet band	Class D special powder	Class D	Class D
Black band	Carbon dioxide (CO2)	Class B, Electrical	Class B, Class C
Canary yellow band	Wet chemical	Class F	Class K
White body	Water mist	Class A, Class B, Class C, Electrical	—
Green band	Clean agent (green)	Class A	Class B, Class C

Each row links to the words the guidance uses, including what not to use it on. A dash means none of the guidance on these pages names a class for it in that system.

US labels: letters, numbers and pictures

US labels may carry picture symbols as well as letters. NFPA 10 (Standard for Portable Fire Extinguishers) sets out recommended markings in an annex; the standard is free to read on nfpa.org only after signing in, so this page does not redraw or describe those pictures. The letters are the part OSHA describes: The letters (A, B, and C) represent the type(s) of fire for which the extinguisher has been approved. US Occupational Safety and Health Administration (OSHA), eTool: Evacuation Plans and Procedures, Portable Fire Extinguishers, Extinguisher Basics, How a fire extinguisher is classified

The US workplace rule on choosing extinguishers:

Portable fire extinguishers shall be provided for employee use and selected and distributed based on the classes of anticipated workplace fires and on the size and degree of hazard which would affect their use. US Occupational Safety and Health Administration (OSHA), 29 CFR 1910.157, Portable fire extinguishers, 1910.157(d)(1)
Where the employer has provided portable fire extinguishers for employee use in the workplace, the employer shall also provide an educational program to familiarize employees with the general principles of fire extinguisher use and the hazards involved with incipient stage fire fighting. US Occupational Safety and Health Administration (OSHA), 29 CFR 1910.157, Portable fire extinguishers, 1910.157(g)(1)

What these pages cannot do

They cannot tell you whether to tackle a fire. The official line is at the top of every page.
They never say an extinguisher is right for every fire; each page quotes what the guidance says it is not for.
They identify the extinguisher by colour and letter; the label on the one in front of you names its own ratings.

Left out, and why

A separate lithium-ion extinguisher page: The only official line we found is London Fire Brigade GN08 §3.5 on green-coded extinguishers, so it sits on the green page rather than standing alone. No official guidance we read gives lithium-ion batteries a class letter.
Drawings of the NFPA 10 annex picture labels and of the BS EN 3 pictograms: We draw our own simple badge per class. We could not read the NFPA 10 annex text without an account, and we do not copy standard artwork.
How to operate an extinguisher: The official line is that the instructions are on the extinguisher itself, and that training is the employer’s job (OSHA 1910.157(g)(1)). These pages only identify what you are looking at.

Sources

Official guidance only. Words in quotation marks are theirs; the drawings are ours.

HM Government (GOV.UK): A guide to making your small non-domestic premises safe from fire (accessible version) (updated 20 January 2025). Quoted here: section ‘Fire extinguishers’. www.gov.uk Checked 2026-09-29.
US Fire Administration (FEMA): Choosing and Using Fire Extinguishers (page last reviewed 1 April 2023). Quoted here: ‘Help people decide when to use a fire extinguisher’. www.usfa.fema.gov Checked 2026-09-29.
London Fire Brigade (London Fire Commissioner): Fire Safety Guidance Note GN08: Hand Held Portable Firefighting Equipment, Rev 20 (January 2025). Quoted here: §4.1; §4.3; §4.2. www.london-fire.gov.uk Checked 2026-09-29.
HM Government (GOV.UK): Fire safety risk assessment: offices and shops (accessible version) (updated 12 September 2023). Quoted here: Part 1, 3.4.2, Figure 8. www.gov.uk Checked 2026-09-29.
US Occupational Safety and Health Administration (OSHA): eTool: Evacuation Plans and Procedures, Portable Fire Extinguishers, Extinguisher Basics (no date shown). Quoted here: How a fire extinguisher is classified. www.osha.gov Checked 2026-09-29.
US Occupational Safety and Health Administration (OSHA): 29 CFR 1910.157, Portable fire extinguishers (current regulation text). Quoted here: 1910.157(d)(1); 1910.157(g)(1). www.osha.gov Checked 2026-09-29.