
Imagine this: a large truck carrying chemicals is involved in an accident on a busy motorway. First responders rush to the scene, but there are no shipping papers available. How do they know what they’re dealing with? That’s where labels, marks, and placards come in, they are the silent heroes of hazardous material transportation.
Hazard Labels
Hazard labels, otherwise known as hazard warning diamonds, serve as identifiers for hazardous materials and have a universal role in conveying the potential risks associated with the materials contained within a package. Compliance with regulations regarding colour, shape, and size is essential for these labels as they aid shippers in generating shipments that adhere to regulations; assist forwarders, cargo agents, and operators in correctly segregating materials for storage and transportation; and aid emergency responders in effectively managing incidents or accidents involving these materials.
Hazard labels are placed on small means of containment – packages, packagings, or overpacks etc which typically get loaded into trucks.
Colour, symbols, numbers, and general format, of hazard labels must meet the specifications stated in the relevant regulations.
- The label must be shaped like a diamond (square on point) with an inner border 5mm in, running parallel to the edge of the label.
- Dimensions of 100 mm x 100 mm (unless the package is too small to accommodate this).
- The hazard Class must be shown as a number in the bottom corner of the label in a height of not less than 10mm.
- The label must be displayed on a background of contrasting colour, or have a dotted or solid outer boundary line.
- The label must be weather resistant and durable enough to withstand the conditions incident to transportation.
Each hazard class has its own associated hazard labels. Classes range from 1 to 9 and are separated by distinct hazardous properties and shipping requirements.
- Class 1 – Explosives
- Class 2 – Gases
- Class 3 – Flammable and Combustible Liquids
- Class 4 – Flammable Solids
- Class 5 – Oxidizing Substances, Organic Peroxide
- Class 6 – Toxic Subtances and Infectious Substances
- Class 7 – Radioactive Material
- Class 8 – Corrosives (Liquids and Solids)Hazard Class
- Class 9 – Miscellaneous Hazardous Materials
Marks
A ‘mark’ is neither a label nor a placard but rather another form of text, symbol or pictogram used to communicate special warnings or information on the products being carried. These range in scope from signs of danger to indications of methods of proper recycling and disposal. Basically, marks provide additional safety, handling, and environmental information.
Although the ‘Limited Quantity’ and ‘Environmentally Hazardous’ marks have the same dimensions as hazard warning labels, these are considered as marks and not labels.
Markings can be affixed to the surface of the package or they can be directly printed onto the package.
Marks can also include:
- The Proper Shipping Name
- The UN/ID number of the material
- The weight of the package
- Name and address of the shipper
- Orientation arrows
- Information (such as centre of gravity).
Placards
Now, picture the same truck from our opening scene – placards are the large, visible diamonds on the vehicle or container. They’re meant to catch your eye from a distance and alert everyone around—especially emergency responders—to the hazards present.
Key points about placards:
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Diamond-shaped and at least 250 mm per side.
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Must appear on all four sides of trucks, railcars, and containers.
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Include the hazard class number in the bottom corner (≥41 mm high).
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Made from durable materials that withstand all weather conditions.
Placards can literally be the difference between a controlled response and a disaster, especially when papers are missing or inaccessible.
Placards can be made of a durable label, a flexible laminated material (such as magnetic rubber), or stuck or embossed onto metal plates and panels.
- Each placard must be diamond shaped and must measure at least 250mm on each side.
- Bulk packages, trucks, freight containers, railcars, and intermodal containers must be placarded on all four sides.
- The hazard class number of the material being transported must be displayed at the bottom corner of each placard.
- The text and class numbers included in the placard must measure at least 41 mm.
- The placards must be made of durable material and must be able to withstand exposure to open weather.
- The placards must be securely affixed to the containers or transport vehicles.
Although the enlarged ‘Limited Quantity’ and Environmentally Hazardous’ marks have the same dimensions as hazard warning placards (250mm x 250mm), these are still considered as marks and not placards.
To Summarise
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Labels = quick hazard identifiers on packages.
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Marks = extra safety and handling instructions.
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Placards = large, visible alerts for vehicles, tanks and containers.
Reference should always be made to the relevant regulations to ensure compliance.
How can Hibiscus Help?
Hibiscus has over 40 years’ experience in the manufacturing of quality bespoke chemical labels and we are one of the UK’s leading manufacturers of off-the-shelf ADR hazard warning diamonds and placards.
Hibiscus has developed software for the classification and labelling of hazardous substances and the authoring and management of Safety Data Sheets and we also provide laser sheet labels, printers, and support to enable companies to print their own labels in-house.
Buy Labels, Marks and Placards directly online.
If you need assistance with any aspects of the labelling your products, you can call us on: 0113 242 4272
Email: Enquiries@hibiscus-plc.com

