CDL Hazardous Materials Endorsement (HME)Communication RulesMedium
A driver is transporting 500 pounds of UN1830, Sulfuric acid, with more than 51% acid, Packing Group II, Class 8. The driver also has 600 pounds of UN1993, Flammable liquids, N.O.S., Packing Group II, Class 3. Both are in non-bulk packages. What placards are required on the vehicle?
- ABoth CORROSIVE and FLAMMABLE placards.
- BOnly a FLAMMABLE placard.
- CNo placards are required.
- DOnly a CORROSIVE placard.
Show answer & explanationAnswer & explanation
Correct answer: A. Both CORROSIVE and FLAMMABLE placards.
The general placarding threshold is 1,001 pounds for most hazardous materials (Table 2). Here, the Corrosive material is 500 lbs and the Flammable Liquid is 600 lbs. Individually, neither meets the 1,001 lb threshold. However, since the aggregate gross weight of all Table 2 hazardous materials is 500 + 600 = 1,100 lbs, which exceeds 1,001 lbs, both hazard classes must be placarded.
Why the other options are wrong
- B. This would only be correct if the corrosive material did not meet its placarding threshold or was not present.
- C. The aggregate weight of 1,100 lbs requires placarding for both classes.
- D. This would only be correct if the flammable liquid did not meet its placarding threshold or was not present.
Aggregate Placarding Rule
If the total aggregate gross weight of all Table 2 hazardous materials in non-bulk packages on a vehicle exceeds 1,001 pounds, then placards for each class present must be displayed.
- Applies to Table 2 materials.
- Considers the combined weight of all applicable hazmat.
- If threshold met, each specific hazard class must be placarded.
Memory trick: Add the weights, then apply the signs!