Practice question What is the toll-free number for the EPA's National Response Center? 800-424-9300800-424-8802800-535-0202800-262-8200 Answer: B — 800-424-8802 The correct answer is shown above. Try the full quiz for additional practice. Practice more: Hazmat Incident Commander Practice Questions - NFPA 470 Hazardous Materials Incident Commander Certification Exam Exam →