Hazardous materials placards, or hazmat placards, are essentially warning signs that are used to indicate the transportation of dangerous goods by road or rail. They take the form of diamond sign in various colour, with a hazmat symbol, a description of the hazardous material in transport and a number to indicate hazmat class code for the dangerous material in question. I have listed the criteria for the various classes and the meanings of these hazmat signs further down the page, below the image and download link.
These free hazmat placards that I have made available for download are those specified by the U.S. Department of Transportation, or USDOT, for use with in the United States of America. Please note that while these same hazardous materials signs are used by most other countries, there may be some slight differences in the class classifications.
Download: Hazmat Placards
File Type: AI (Illustrator)
Hazmat Sign Meanings
1. The DANGEROUS sign or placard is used when carrying 2 or more hazardous materials
Class 1 Hazardous Materials: Explosives Placards
2. Class 1.1 Explosive Materials: Used to denote a material that poses a mass explosion hazard such as TNT or dynamite.
3. Class 1.2 Explosive Materials: Used to denote a material that poses a severe projection or blast hazard
4. Class 1.3 Explosive Materials: Used to indicate materials that pose a minor blast hazard. This may include rocket fuel
5. Class 1.4 Explosive Material: Indicates materials that pose a major fire hazard, including consumer fireworks and ammunition
6. Class 1.5 Explosive Materials: Used to indicate blasting agents
7. Class 1.6 Explosive Materials: This placard indicates a load of extremely insensitive explosives. These are explosives with very little regard for other people feelings – you might like to think of them as narcissistic explosives. But really… these are materials that pose very little threat of accidental ignition.
Class 2 Hazardous Materials: Gases
8. Class 2.1 Gases: This placard indicates the presence of a flammable gas that must be not be exposed to any potential source of ignition. These gases include hydrogen, butane & methane etc.
9. Class 2.2 Gases: Used to denote gases which are neither flammable or poisonous. This includes gases such as neon, helium or nitrogen
10. Class 2.3 Gases: This placard denotes poisonous gases that will cause serious injury or death if inhaled by humans. eg: fluorine or chlorine
11. Alternative Placard for Class 2.2 Gas: This denotes the transportation of oxygen
Class 3 Hazardous Materials: Flammable Liquids
12. Class 3 Flammable Liquid Placard
13. Class 3 Combustible Liquid Placard
14. Class 3 Fuel Oil Placard
15. Class 3 Gasoline Placard
Class 4 Hazardous Materials: Flammable Solids
16. Class 4.3 Flammable Soldis: Dangerous When Wet. This denotes a solid material which emits a flamable gas when wet or has a violent reaction when it comes in contact with water. Examples include sodium or potassium.
17. Class 4.1 Flammable Solids: This indicates easily ignitible substances that will combust if exposed to an ignition source. Examples include magnesium or commercial fire-lighters
18, Class 4.2 Flammable Solids: This sign indicates Spontaneously Combustible Solids such as white phosphorus. Nasty stuff.
Class 5 Hazardous Materials: Oxidizing Agents & Organic Peroxides
19. Class 5.1 Oxidizing Agent: Indicates all oxidising agents other than organic peroxides
20. Class 5.2 Organic Peroxides: Indicates solid or liquid form organic peroxides such as 2-butanone peroxide
Class 6 Harzardous Materials: Toxic and Infectious Substances
21. Class 6.1 Inhalation Hazard: Materials which are specifically toxic via inhalation
22. Class 6.1 Poison: Indicates materials in transport which are hazardous to human health if inhaled, swallowed or absorbed by the skin
23. Class 6.1 Toxic Materials: This includes materials such as cyanide solutions or pesticides
Class 7 Hazardous Materials: Radioactive Substances
24. Class 7 Radioactive Materials: Indicates substances such as plutonium or uranium which release ionising radiation
Class 8 Hazardous Materials: Corrosive Substances
25. Class 8 Corrosive Materials: Indicates the presence of substances that will corrode metals or dissolve organic tissues including human skin
Class 9 Hazardous Materials: Miscellaneous
26. Class 9 Miscellaneous Hazardous materials: Includes substances or products that are not covered by any of the other categories such as asbestos, dry ice or a whole range of other nasties. The world is a dangerous place… you best stay indoors!
For more detailed information on the materials covered by each class, please visit the Environmental Chemistry website.
Signs & Symbols 
