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CDL · Communication Rules

What does Hazard Class 1 represent?

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Correct answer

Explosives

  1. A Flammable liquids
  2. B Explosives
  3. C Gases
  4. D Corrosives

Why this is the answer

HAZARD CLASS 1 is EXPLOSIVES — materials that can rapidly release gas and heat (detonate or deflagrate), such as dynamite, ammunition, fireworks, and blasting agents. CDL hazmat. Class 1 is divided into DIVISIONS (1.1 through 1.6) based on the type/degree of explosive hazard (1.1 = mass explosion hazard, the most dangerous). Explosives have the strictest transport requirements: special routing, attendance, no smoking nearby, compatible loading, and security. Class A/B explosives generally cannot be transported on buses with passengers. The explosive placard is orange. Knowing Hazard Class 1 = explosives (and that it's the most strictly regulated) is part of the hazard class system commonly tested on the hazmat exam.
Source: FMCSA CDL Manual — Hazmat, Hazard Class 1

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About this topic: Communication Rules

Communication rules cover shipping papers, placards, labels and markings: what each must show, where papers must be kept in the cab, and when placards are required. This is the most heavily tested hazmat topic. This is one of 19 Hazardous Materials questions on communication rules, each with a full explanation on a single study page.

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