A Dust Hazard Analysis (DHA) is the most important and fundamental step for minimizing fire and explosion risks in a grain or milling operation. As mandated by NFPA 652 and referenced by NFPA 61, the DHA is a systematic review to identify and evaluate the specific combustible dust hazards present. This analysis forms the basis for all other safety decisions. The results of the DHA determine the necessary preventive and protective measures, including appropriate housekeeping procedures, ignition source controls (such as eliminating static electricity), and engineering controls. Without a DHA, any safety measures implemented would be presumptive rather than based on a documented, systematic evaluation of the actual risks.

A. This is a specific ignition control measure; a DHA is required to identify this and all other potential ignition sources that must be managed.

B. Using compressed air for blowdowns is generally discouraged by NFPA 61 as it can create a dangerous dust cloud, making it a potentially unsafe practice.

D. This is one specific housekeeping technique. The DHA determines which housekeeping methods are necessary and their required frequency based on the facility's specific risks.

1. NFPA 652, Standard on the Fundamentals of Combustible Dust, 2019 Edition. Chapter 7, "Dust Hazard Analysis (DHA)," Section 7.1.2, mandates that a DHA shall be performed for existing processes and facility compartments where combustible dust is present. The entire chapter outlines its foundational role.

2. NFPA 61, Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities, 2020 Edition. Section 7.2.1 requires that a Dust Hazard Analysis (DHA) be performed for the facility and processes in accordance with Chapter 7 of NFPA 652.

3. SFPE Handbook of Fire Protection Engineering, 5th Edition. Chapter 55, "Explosions," Section 55.5.2, "Hazard Assessment," emphasizes that a formal hazard assessment, such as the DHA required by NFPA 652, is the essential first step in managing dust explosion risks.