CDL Hazardous Materials Endorsement (HME)Communication RulesHard

A driver is transporting a bulk quantity of UN1005, Anhydrous Ammonia, Class 2.2, with a subsidiary hazard of Class 2.3 (Poison Inhalation Hazard). The material is in a cargo tank. In addition to the Class 2.2 placard and the identification number, what specific marking is required on the cargo tank for this material?

  1. AThe letters 'RQ' near the identification number.
  2. BThe words 'INHALATION HAZARD' on two opposing sides.
  3. CA Class 6.1 (Poison) placard.
  4. DThe words 'POISON GAS' on all four sides.
Show answer & explanation

Correct answer: B. The words 'INHALATION HAZARD' on two opposing sides.

Anhydrous Ammonia (UN1005) is a known Poison Inhalation Hazard (PIH). For bulk packaging containing a PIH, the words 'INHALATION HAZARD' must be displayed on two opposing sides of the cargo tank, in addition to the placards and identification number.

Why the other options are wrong

  • A. The 'RQ' marking is for reportable quantities of hazardous substances, which is different from the PIH marking requirement.
  • C. Anhydrous Ammonia is a Class 2.2 (non-flammable, non-poisonous gas) with a subsidiary PIH, not a Class 6.1 poison. The appropriate placard is Class 2.2.
  • D. While it is a poison gas, the specific marking for a PIH in bulk is 'INHALATION HAZARD', not 'POISON GAS'.

Bulk PIH Vehicle Marking

Bulk packagings (e.g., cargo tanks, portable tanks) containing a Poison Inhalation Hazard (PIH) must be marked with the words 'INHALATION HAZARD' on two opposing sides.

  • Applies to bulk quantities of PIH materials.
  • Words must be 'INHALATION HAZARD'.
  • Displayed on two opposing sides of the vehicle/container.

Memory trick: PIH in 'Bulk'? Make sure they 'Inhale the Hazard Warning'!

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