
Class 1 Explosives Placards Explained (Divisions 1.1 to 1.6)
What the orange Class 1 explosives placard means, the six divisions from 1.1 to 1.6, compatibility groups, and which ones must be placarded in any amount.
Posts tagged Hazard Classes from the CDL Placards team.

What the orange Class 1 explosives placard means, the six divisions from 1.1 to 1.6, compatibility groups, and which ones must be placarded in any amount.

Class 2 gases come in three colors for three divisions: red flammable gas, green non-flammable gas, and white toxic gas. Here is how to tell them apart.

The red Class 3 placard is the one drivers see most. Here is what it means, the common materials behind it, and the UN numbers worth recognizing.

Class 4 has three very different divisions: flammable solids, spontaneously combustible materials, and dangerous-when-wet. Here is how to tell the placards apart.

Class 5 has two yellow-leaning divisions that students mix up. Here is how oxidizers (5.1) and organic peroxides (5.2) differ and how to read each placard.

Class 6 covers toxic substances and infectious substances. Here is what the skull-and-crossbones and biohazard placards mean, plus the inhalation-hazard rule.

What the yellow-over-white Class 7 radioactive placard means, the trefoil symbol, the label categories, and when the radioactive placard is required.

What the white-over-black Class 8 corrosive placard means, the dripping-liquid symbol, common examples, and how to avoid confusing it with toxic placards.

What the black-and-white striped Class 9 placard means, why lithium batteries and dry ice fall here, and the quirky domestic placarding rules.

What the letter on a Class 1 explosives placard means, how compatibility groups decide what can travel together, and why 1.1D looks the way it does.

What the blue dangerous-when-wet placard means, why it is the only blue diamond, which materials carry it, and why it must be placarded in any amount.

Flammable and combustible liquids are both Class 3 but split on flash point. Here is the dividing line, the placards, and why diesel sits near the edge.

A plain-English breakdown of the nine DOT hazard classes, what each one covers, the placard color and symbol that signal it, and how to memorize them.

A guide to every hazmat placard symbol: the flame, skull, trefoil, exploding bomb, dripping corrosive, and more, plus what each one tells you instantly.

Mnemonics, chunking, and active-recall techniques to memorize the nine DOT hazard classes in order, plus how to anchor each one to its placard.

Why lithium batteries are regulated, the UN numbers and marking that identify them, and the special rules around fire risk and damaged batteries.

The placard pairs that trip up CDL students most, from red gas versus red liquid to yellow oxidizer versus organic peroxide, and the one detail that tells each apart.

Why hazmat placards look almost the same worldwide, how the US system relates to the UN model, and the main differences across ADR, TDG, IMDG, and IATA.

How the U.S. Department of Transportation defines a hazardous material, how materials are classified, who decides, and how it relates to dangerous goods.

A clear, step-by-step way to read any Hazmat placard: color, symbol, class number, and ID number, in that order.

What each Hazmat placard color signals, why color is the fastest first clue, and where color alone is not enough.