Practice question A vapor density of 2.0 means the gas/vapor will: Rise into the upper atmosphereSink and accumulate in low areasStay neutral with airBurn instantly Answer: B — Sink and accumulate in low areas 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 →