Interpreting HAZMAT Placards
Have you ever seen diamond-shaped signs attached to large trucks and wondered what they were or why they were there?
These labels are known as hazardous material placards and they provide info about what kind of hazardous freight the vehicle is carrying. If you’re curious about what each of these HAZMAT symbols mean, or if you need help deciding which placard is right for your shipment, this guide can better assist.
- Hazard Class 1: Explosives or combustible substances. Class 1 explosives are illustrated by an orange placard with their designated hazard class, division number or compatibility letter displayed at the bottom. Some also display an explosion graphic.
- Hazard Class 2: Compressed gases – These are split into four categories: flammable/combustible gases, non-flammable/non-poisonous gases, toxic/poisonous gases, and oxygen.
- Hazard Class 3: Flammable liquids – These liquids include paints, alcohols, gasoline, kerosene and ethanol, and are recognized by red “flammable liquids” placards with the hazard class No. 3 at the bottom, and display a flammable liquid graphic at the top.
- Hazard Class 4: Flammable solids – There are three versions in this class, including flammable solids, spontaneously combustible materials, and substances that are dangerous when wet.
- Hazard Class 5: Oxidizing chemicals that could be prone to combustion. There are two divisions to this class — oxidizers and organic peroxides. Oxidizers are designated with a yellow label. Organic peroxides are noted with a half-red and half-yellow truck placard, with a flammable graphic at the top in the red portion.
- Hazard Class 6: Poisonous substances – These substances are divided into two classes: poisonous and biohazardous substances such as medical waste.
- Hazard Class 7: Radioactive substances – Radioactive substances are distinguished by yellow and white HAZMAT signs, with a radioactive symbol in the top, yellow portion and the hazard class No. 7 at the bottom, on the white section.
- Hazard Class 8: Corrosive substances – These could include chemicals such as potassium hydroxide, hydrochloric acid, and sodium hydroxide. These placards are half-white and half-black, with a corrosive liquid graphic in the white upper portion, and the hazard class No. 8 on the black, lower part.
- Hazard Class 9: Miscellaneous dangerous goods – These include lithium batteries, asbestos, dry ice and other consumer commodities. These products are identified by a half-white and half-black-and-white-striped sign, with the hazard class No. 9 located at the base.
UN/NA numbers
Some of these placards display four-digit numbers in the middle. These numbers are called United Nations (U.N.) numbers, and are assigned by the U.N. to help identify international HAZMAT cargo.
Some hazardous chemicals have specific HAZMAT U.N. numbers, like ammonia, which is designated as UN 1005, while other hazardous materials have a more broad designation.
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We hope this guide was of some use to you, whether to put into application or just for general knowledge.
