CDL Hazardous Materials Endorsement (HME)Communication RulesMedium
A driver is transporting a shipment of UN1072, Oxygen, compressed, Class 2.2, in a cargo tank motor vehicle. The vehicle is placarded with a 'NON-FLAMMABLE GAS' placard. What additional specific placard is required if the total weight of oxygen in the cargo tank exceeds 1,001 pounds?
- AA 'BLASTING AGENT' placard.
- BAn 'OXYGEN' placard.
- CA 'FLAMMABLE GAS' placard.
- DA 'DANGEROUS' placard.
Show answer & explanationAnswer & explanation
Correct answer: B. An 'OXYGEN' placard.
While Oxygen is a non-flammable gas, if transported in bulk (like a cargo tank) or in quantities exceeding 1,001 pounds (gross weight) in non-bulk packages, an 'OXYGEN' placard (Class 2.2, Division 5.1) is specifically required instead of or in addition to the general 'NON-FLAMMABLE GAS' placard. This highlights its oxidizing properties.
Why the other options are wrong
- A. 'BLASTING AGENT' is for Class 1 explosives, not oxygen.
- C. Oxygen is a non-flammable gas; a 'FLAMMABLE GAS' placard would be incorrect.
- D. A 'DANGEROUS' placard is a general placard used when multiple hazards are present and specific placards aren't required, but 'OXYGEN' is a specific requirement here.
Specific Oxygen Placard
When transporting oxygen in bulk or in amounts over 1,001 pounds, a specific 'OXYGEN' placard is required to highlight its oxidizing hazard.
- Applies to UN1072, Oxygen, compressed.
- Required for bulk packaging or quantities > 1,001 lbs.
- Replaces or supplements 'NON-FLAMMABLE GAS' placard.
- Emphasizes the oxidizing property (Class 5.1 subsidiary hazard).
Memory trick: Oxygen's special placard, for big loads, shows its fire hazard.