Practice question DOT Class 2 Division 2.3 indicates which sub-hazard? Flammable gasNon-flammable gasToxic (poison) gasOxygen Answer: C — Toxic (poison) gas The correct answer is shown above. Try the full quiz for additional practice. Practice more: Hazmat Awareness Practice Questions - NFPA 470 Hazardous Materials Awareness-Level Responder Certification Exam →