CDL Hazardous Materials Endorsement (HME)Communication RulesHard
A driver is transporting four large cylinders, each containing 250 pounds of UN1072, Oxygen, compressed, Class 2.2. The total gross weight of the cylinders and contents is 1,200 pounds. What type of placard is required on the vehicle?
- ANo placards are required.
- BOXYGEN
- CDANGEROUS
- DNON-FLAMMABLE GAS
Show answer & explanationAnswer & explanation
Correct answer: B. OXYGEN
UN1072, Oxygen, compressed, is a Class 2.2 material. However, Oxygen has its own specific placard, the OXYGEN placard, when transported in quantities exceeding 1,001 pounds in non-bulk packaging. Since the total gross weight is 1,200 pounds, which exceeds the 1,001-pound threshold for Table 2 materials, the vehicle must be placarded. The OXYGEN placard is specifically prescribed for this material (49 CFR 172.504(f)(7)).
Why the other options are wrong
- A. The total gross weight of 1,200 pounds exceeds the 1,001-pound threshold for Table 2 materials, so placarding is required.
- C. The DANGEROUS placard is for mixed loads under specific conditions, not for a single hazardous material with its own specific placard.
- D. While Oxygen is a non-flammable gas (Class 2.2), it has a specific 'OXYGEN' placard that takes precedence over the general 'NON-FLAMMABLE GAS' placard when its quantity exceeds the placarding threshold.
Specific Oxygen Placard
The 'OXYGEN' placard is specifically required for shipments of UN1072, Oxygen, compressed or refrigerated liquid, when the quantity exceeds the placarding threshold, overriding the general 'NON-FLAMMABLE GAS' placard.
- Applies to UN1072 (Oxygen).
- Required over 1,001 lbs (non-bulk).
- Overrides general Class 2.2 placard.
Memory trick: Oxygen's special, blue and bold, no 'non-flammable,' stories told.