Using the DOT ERG, the hazard class number assigned for vinyl chloride with the ID #1086 is:

• A. 1
• B. 3
• C. 4
• D. 2

Answer: (D)

The main idea here is recognizing the primary hazard category assigned to a substance in the DOT ERG. For vinyl chloride, UN number 1086, the primary hazard is that it is a gas. In the DOT ERG, gases are classified under hazard class number 2. So the correct answer is the one that corresponds to 2. This classification stays true even though vinyl chloride is also toxic and flammable, because the ERG’s primary hazard for this material is as a gas. The other numbers correspond to different kinds of hazards (solids, liquids, explosives), which do not apply as the main hazard for vinyl chloride. In practice, responders use the 2 gas classification to guide initial actions, focusing on gas-specific safety measures such as avoiding ignition sources and ensuring proper ventilation, while also considering the toxic inhalation risk.