Practice question What does IDLH stand for? Industrial Decontamination Level HazardImmediately Dangerous to Life or HealthInternal Dose-Limit HazardInhalation Decontamination Limit Hour Answer: B — Immediately Dangerous to Life or Health The correct answer is shown above. Try the full quiz for additional practice. Practice more: Hazmat Operations Practice Questions - NFPA 470 Hazardous Materials Operations Exam →