If your job involves investigating fires and explosions, then you need the latest NFPA 921, Guide For Fire & Explosion Investigations. Revised and updated for the 2017 edition, this document is the premier source for rendering scientific based opinions on origin and cause investigations along with incident responsibility. NFPA 921 describes in detail the scientific method to apply in fire and explosion investigations. Public and private professionals have long seen NFPA 921 as a valuable resource in the field and in training. It's also becoming increasingly relevant in U.S. federal and state courts, where the document is used to evaluate the reliability of fire investigations in both civil and criminal trials. Recently NFPA 921 became a recommended guide for fire investigation by the Organization of Scientific Area Committees (OSAC) -- a collaborative body of more than 600 forensic science practitioners and experts who recommend forensic science consensus standards and guidelines. Complying with NFPA 921 can support a fire investigator's opinion; not complying can result in serious challenges to your testimony.