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CDL · Communication Rules

What does Hazard Class 2 represent?

Reviewed by Jordan Morley, Editorial Lead at 247SimpleTests. Written by the 247SimpleTests Editorial Team from the official source material cited on every question.

Correct answer

Gases (including flammable gases, non-flammable gases, and poisonous/toxic gases)

  1. A Gases (including flammable gases, non-flammable gases, and poisonous/toxic gases)
  2. B Corrosives
  3. C Explosives
  4. D Radioactive materials

Why this is the answer

HAZARD CLASS 2 is GASES, divided into divisions: Division 2.1 — FLAMMABLE gases (propane, hydrogen, acetylene); Division 2.2 — NON-FLAMMABLE, non-toxic gases (helium, nitrogen, compressed air, oxygen); Division 2.3 — POISONOUS/TOXIC gases (chlorine, certain others — among the most dangerous). CDL hazmat. Gases are often transported under pressure (in cylinders or tanks), adding the hazard of a pressurized container that could rupture/explode (especially if heated). Each division has its own placard. Poison gas (2.3) and flammable gas (2.1) carry significant hazards. Understanding the hazard class system helps drivers recognize and handle the materials safely. Knowing Hazard Class 2 = gases (with its divisions) is commonly tested hazmat knowledge.
Source: FMCSA CDL Manual — Hazmat, Hazard Class 2

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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.

New to this exam? Our CDL exam guide explains the format, scoring, and how to prepare.

Related questions

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When transporting hazardous materials, where must the shipping papers be kept?

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