The Class 1 placard is easy to spot, because orange appears nowhere else in the system. The part that actually matters on the test is the division number, which tells you how the material behaves. A 1.1 and a 1.4 are both explosives, but they are not the same risk, and the rules treat them differently.
This is study guidance, not regulatory advice. The binding definitions are in 49 CFR 173.50 and your official state CDL manual.
The six divisions
| Division | Hazard | Examples |
|---|---|---|
| 1.1 | Mass explosion hazard | Dynamite, TNT |
| 1.2 | Projection hazard, no mass explosion | Some ammunition |
| 1.3 | Fire hazard with minor blast or projection | Display fireworks, propellants |
| 1.4 | Minor explosion hazard, effects mostly contained | Small-arms ammunition |
| 1.5 | Very insensitive, but mass explosion possible | Blasting agents |
| 1.6 | Extremely insensitive articles, no mass explosion | Certain military articles |
The numbering runs from most dangerous (1.1) to least (1.6), which makes the order easy to remember.
What is on the placard
The orange diamond shows an exploding-bomb symbol on divisions 1.1 through 1.3, the division number, and usually a compatibility group letter (such as 1.1D). The compatibility group tells handlers which explosives can be safely transported together. For 1.4, 1.5, and 1.6 the symbol is replaced by the large division number and group letter. To work through every element of the diamond in order, see how to read a hazmat placard.
When Class 1 must be placarded
Divisions 1.1, 1.2, and 1.3 are Table 1 materials, so they must be placarded in any amount, no matter how small the load. Divisions 1.4, 1.5, and 1.6 are Table 2 materials, placarded once the total reaches 1,001 pounds. The full logic is in when hazmat placards are required, and the placarding rule itself is 49 CFR 172.504.
Where it fits
Class 1 is the first of the nine hazard classes, and because explosives carry some of the strictest handling rules, the FMCSA hazardous materials regulations and the PHMSA Emergency Response Guidebook cover them in detail. For the test, focus on recognizing the orange diamond instantly and knowing that the division number, not just the class, drives the rules.
A deeper detail: compatibility groups
The letter that often appears with the division, as in 1.1D, is the compatibility group, which controls what explosives can travel together. It has its own guide in compatibility groups for explosives.
Frequently asked questions
What color is the Class 1 explosives placard?
It is orange. Orange is unique to Class 1 in the placard system, so the color alone tells you that you are looking at explosives before you read the division number.
What do the Class 1 divisions mean?
They rank the explosion risk from 1.1 (mass explosion hazard) down to 1.6 (extremely insensitive articles). Divisions 1.1, 1.2, and 1.3 are the most dangerous and must be placarded in any amount.
What is a compatibility group on an explosives placard?
It is a letter, such as the D in 1.1D, that indicates which explosives can be transported together safely. It appears next to the division number on the placard.
What is the best way to study the Class 1 placard for the CDL test?
Learn that orange always means explosives, then drill the divisions and what each signals. A recognition app such as CDL Placards lets you practice the orange diamond and its division numbers in short sessions, with your state CDL manual as the authority on the rules.
