Combustible dust is a critical hazard in food and agriculture in areas such as grain elevators, feed mills, sugar plants, and grain processors. Fine dust suspended in the air can ignite and cause powerful flash fires or explosions. On average, there are 28 dust explosions, fires, and incidents worldwide every year. Recognizing this danger, NFPA has released NFPA 660 (2025), effective December 6, 2024, a consolidated combustible-dust standard that replaces the older, industry-specific rules. 

NFPA 660 combines previous codes such as NFPA 61 (Agriculture/Food Processing), NFPA 652 (Fundamentals), NFPA 654, NFPA 655, NFPA 664, and others into a single unified code. This change – the result of a technical committee of subject-matter experts working together – was intended to clarify ambiguities and improve safety beyond the legacy standards. In effect, NFPA 660 now provides one “one-stop” reference for dust hazard management across all industries, including grain and feed.

Legacy Dust Standards and Their Limits

For decades, combustible-dust safety in grain and food operations was governed by multiple NFPA standards. NFPA 61 (whose roots date back to 1923) covered fires and dust explosions in agricultural and food facilities, while NFPA 652 (introduced in 2016) provided generic “fundamental” requirements for all dust-handling industries. Other NFPA codes addressed metals, wood, sulfur, etc. Although each standard addressed specific hazards, using several overlapping documents caused confusion and compliance gaps. 

For example, NFPA 61 had its own housekeeping and maintenance rules that did not always align with NFPA 652’s requirements. Facilities often had to juggle multiple manuals, leading to inconsistent interpretations. 

In practice, grain processors might have been unsure whether to follow NFPA 61 or the new NFPA 652 for specific topics. The new NFPA 660 addresses this by unifying all dust rules under one roof, reducing those inconsistencies.

Why Consolidate Various Industry Standards?

Several factors drove the push to consolidate combustible-dust codes. First, high-profile dust explosions in various industries highlighted the need for consistent safety practices. From 2016 to 2024, the agriculture industry experienced between 7 and 12 dust explosions every year in the United States, with even more worldwide. 

Investigators and regulators stressed that dust hazards transcend commodity lines, so a unified approach makes sense. Secondly, when incidents occurred, enforcement agencies and insurers historically cited the old NFPA standards (or the OSHA General Duty Clause). By creating one comprehensive standard, NFPA aims to “eliminate variability across previous standards” and give industries “clearer and more consistent guidelines” for managing dust risks. 

Industry leaders echo this: in a recent GEAPS webinar introduction, Matt Williamson from ADF Engineering noted NFPA 660’s goals include “enhancing safety through clear protocols for identifying, assessing, and managing dust hazards,” “simplifying compliance by resolving inconsistencies,” and “preventing explosions and fires through best practices” like more rigorous Dust Hazard Analysis (DHA) and explosion protection. 

Ultimately, NFPA 660 was created to raise the minimum safety bar and make it easier for facilities to follow one set of rules instead of many.

What’s New in NFPA 660 for Food & Ag

NFPA 660 reorganizes and updates the requirements. Chapters 1–10 cover general fundamentals; Chapters 21–25 cover specific commodities (Chapter 21 is Food/Agriculture, the old NFPA 61). Key new elements include:

• Dust Hazard Analysis (DHA). NFPA 660 makes DHA central to dust safety. Chapter 7 (DHA) is now mandatory for all facilities (new and existing), including food processing sites. This is more explicit than before. Grain/Agric facilities must thoroughly document combustible dust risks and mitigation strategies. A DHA is required for all new and existing systems. Chapter 21 allows minor process modifications under ~25% of the equipment replacement cost to not trigger a full DHA, though experts caution that any change can introduce hazards.
• Management Systems & Housekeeping. Chapter 8 requires comprehensive management controls, such as employee training, recordkeeping, hot-work permitting, Management of Change (MOC), and operational readiness reviews.

  Housekeeping rules are now more explicit and (for food processing) somewhat more lenient. For example, Chapter 21 allows up to 1/8‑inch of dust on equipment/structures (about 5% of floor area) and permits limited use of compressed air for cleaning.

  However, NFPA 660 still emphasizes eliminating dust accumulations: leaks must be fixed, and routine cleaning schedules must be maintained. In short, the standard codifies best practices – keep equipment tight, maintain good ventilation, and train operators to spot and address dust build-up.

• Equipment and Facility Design. Chapter 9 (Hazard Management) has been dramatically expanded. It includes new requirements for building layout (separation/segregation of dusty areas) and for equipment design and protection.

  Notably, many common food-industry items (feeders, blenders, conveyors, bucket elevators, dryers, etc.) now have specific guidance. The standard states that bucket elevators (common in grain plants) are a “significant hazard” and must be designed and maintained to control ignition sources.

  Explosion protection is integrated by reference: NFPA 660 defers to NFPA 68 (venting) and 69 (all other methods) for active systems, but emphasizes that new plants should build in explosion isolation and detection where needed. In short, equipment must now meet explicit dust-safety criteria that draw from the best of the old standards.

• Emergency Planning and Response. NFPA 660 adds a new Chapter 10 devoted to emergency plans. Dust incidents can produce intense fires and explosions, so owners must develop response plans (fire drills, evacuation, coordination with local fire departments) and review them regularly. This formalizes what was previously scattered in guidance: every plant must now have a written combustion-hazard response plan.

   
Overall, NFPA 660 augments the old NFPA 61 rules for food and grain operations. For instance, Chapter 21 largely restates NFPA 61’s requirements but with clarifications and a few relaxations. Large agribusinesses with true dust hazards must comply fully, whereas “family” farms without significant dust handling are essentially exempt from Chapter 21, though this may change in the future. 

In other areas, Chapter 21 mirrors Chapter 1–10 fundamentals with tweaks: it explicitly incorporates “ingredient transfer systems” exemptions, refines rules for dust collectors and vacuum cleaners in food service, and retains most dryer-related provisions from NFPA 61 with minor updates. In short, NFPA 660’s food chapter stitches together the essentials of the old Ag/Feed standard with the new general rules.

Grain/Food Operation Compliance Steps for NFPA 660

Facilities in the grain, feed, milling, or food-processing industries should take immediate action to align with NFPA 660. Key steps include:

• Identify Combustibility & Test Dusts: First, determine which materials in the plant are combustible dusts (by testing for explosibility, Kst, Pmax, etc.). NFPA 660 provides the detailed test criteria.
  
  
• Perform a Dust Hazard Analysis (DHA): Using NFPA 660 Chapter 7 guidance, map out every process, room, or compartment where dust is handled or stored. Analyze how dust could be dispersed or ignited, and document measures to eliminate or control those hazards. Even if previous DHS were done under NFPA 652 or 61, they should be updated to the new standard’s format.
  
  
• Upgrade Housekeeping & Controls: Implement a rigorous housekeeping program to prevent dust layers from accumulating. Replace or seal pipe/duct leaks, install blowers or collectors on open operations, and prohibit unfiltered conveying of dust. Follow NFPA 660’s thresholds (e.g., max 1/8″ layer in food facilities) and avoid relying on compressed air except where allowed. Establish hot-work permits and maintenance procedures as required.
  
  
• Ensure Safe Equipment Design: Inspect and, if needed, modify equipment to meet NFPA 660 criteria. For example, use explosion-rated ventilators on dust collectors, install explosion vents or isolation valves on bucket elevators and grinders, and confirm all motors/switches in dusty areas are rated Class II as required. NFPA 660 also demands that any new equipment or renovations follow the standard (or a performance-based equivalent) from day one.
  
  
• Strengthen Management Systems: Update your safety management plan to incorporate NFPA 660’s requirements: perform Management of Change reviews for modifications (even minor ones that are above 25% of equipment cost), conduct pre-startup reviews for new installations, maintain training records, and schedule regular audits. Implement the new Emergency Response chapter by coordinating drills with local fire departments.

   
By systematically applying NFPA 660’s rules, food and ag operations can reduce the risk of dust incidents and demonstrate diligence to regulators. In practice, this might involve hiring a dust safety consultant to perform or review DHAs, investing in better dust collectors or explosion venting on elevators, and updating work procedures.

Even with great safeguards, combustible dust incidents can ignite fierce fires. NFPA 660 explicitly adds a chapter on Emergency Planning and Response to ensure plants are prepared. Facilities must now have written response plans and should share them with local responders. Coordination with firefighters can save lives and property.

Inspections, Insurance, & Enforcement

NFPA 660’s arrival also affects inspections, insurance audits, and AHJ enforcement. OSHA itself does not have a general-duty combustible dust standard (except 29 CFR 1910.272 for grain elevators), so it often relies on NFPA codes when issuing citations under the General Duty Clause. In past inspections, OSHA routinely cited NFPA standards (and housekeeping rules) for hazards in mixers, dryers, silos, bucket elevators, etc..

OSHA’s Combustible Dust Emphasis Program explicitly mentions using NFPA guidance to prove recognized hazards, and OSHA examiners have used NFPA standards heavily in the past. They will almost certainly accept NFPA 660 as the new recognized industry standard.

OSHA citations have increased significantly, with over $3,772,328 in penalties over the last three years, and the maximum penalty has also been increased to as much as $165,514 for willful or repeated violations. 

NFPA 660 serves as a key reference for fire marshals and insurance providers and has been integrated into local fire codes across most states, making it the new standard for facilities. Insurance underwriters often offer premium reductions for dust compliance and will likely favor adherence to NFPA 660, potentially requiring documentation of Dust Hazard Analysis (DHA) and housekeeping practices.

In summary, NFPA 660 signifies a significant advancement in dust safety for the food and agriculture industries. Grain and food processors should leverage this consolidation to streamline their compliance efforts and modernize their procedures and equipment in a coordinated manner.

Grain Safety Equipment, PPE, & Explosion Venting Systems

Need grain and dust safety equipment? IBT will supply the PPE and grain safety equipment you need. 

• Confined space ventilation equipment
• Intrinsically safe lights and flashlights
• Explosion Venting Systems

  
Contact us, and we can recommend an NFPA 660-qualified dust safety consultant in your area to ensure your facility meets the newest standards.