Heavy grain movement, longer operating hours and demanding conditions put added pressure on the safety practices grain facilities manage every day.

Seven agricultural dust explosions were reported in the United States in 2025, fewer than the previous year and below the 10-year average. But the decline in incidents did not translate into less severe consequences.

The seven explosions resulted in 10 injuries and four fatalities, according to Purdue University’s annual summary of agricultural dust explosions. That compares with nine explosions, two injuries and no fatalities in 2024. The 2025 total also remained below the 10-year average of 8.5 explosions.

The incidents occurred across agricultural processing and handling operations, including two grain elevators and one farm-operated grain elevator. The remaining explosions occurred at a seed processing facility, feed mill, flour mill and biofuel plant. Grain dust was identified as the fuel source in five of the seven incidents.

The numbers provide a timely reminder heading into harvest, when the familiar demands of grain handling intensify. Facilities are moving greater volumes, equipment is operating for longer periods and housekeeping and maintenance demands increase at the same time operations have less room for interruption.

Familiar Risks Under Heavier Demand

Purdue University has tracked agricultural dust explosions since 2012 with support from the National Grain and Feed Association. Its research shows that grain dust explosions have continued at a relatively constant rate in the United States over the past decade. The probable ignition sources identified in the 2025 incidents illustrate how closely explosion prevention is connected to routine facility operations. One incident was attributed to smoldering grain, another to equipment maintenance work, one to an overheated bearing and another to a dust fire. The ignition source was unknown in three incidents.

In a Purdue University article written by Olivia De Young about the 2025 findings, Kingsly Ambrose, professor of agricultural and biological engineering and author of the annual report, pointed to preventive maintenance before harvest as an important part of reducing risk. Belt misalignment in a bucket elevator, for example, can create friction and heat in an environment where combustible dust may be present.

OSHA’s grain handling standard puts considerable emphasis on the condition of equipment. Preventive maintenance procedures must include regularly scheduled inspections of mechanical and safety control equipment associated with dryers, grain stream processing equipment, dust collection systems and bucket elevators. Overheated bearings and slipping or misaligned belts associated with inside bucket elevators must be promptly corrected or removed from service.

Those requirements take on additional significance when equipment is operating heavily during harvest. A bearing running hotter than expected, a belt beginning to track improperly or a dust collection system operating below its designed efficiency can become more consequential as operating hours and grain movement increase.

Controlling the Fuel

Equipment is only part of the equation. Grain dust remains the primary cause behind agricultural dust explosions, making housekeeping one of the most established controls in an elevator’s safety program.

OSHA requires grain elevators to maintain a written housekeeping program establishing the frequency and methods used to reduce fugitive grain dust on floors, ledges, equipment and other exposed surfaces. Priority housekeeping areas include floors within 35 feet of inside bucket elevators and enclosed areas containing grinding equipment or grain dryers.

In those priority areas, accumulations cannot exceed 1/8 inch unless the facility can demonstrate equivalent protection through its housekeeping program. OSHA notes that even a 1/8-inch accumulation can provide more than enough fuel for a fire or explosion.

The 2025 incidents reinforce the relationship between dust management and ignition control. Grain dust was the identified fuel in five of the seven explosions. Purdue’s longer-term research also has documented fires, welding, friction sparks, malfunctioning mechanical components, smoldering material and overheated bearings among probable ignition sources in agricultural dust explosions.

The objective is not simply removing dust or eliminating one particular ignition source. A dust explosion requires several conditions to occur together: combustible dust, oxygen, an ignition source, dispersion of the dust and confinement. Purdue illustrates those conditions through the dust explosion pentagon and notes that eliminating one element can prevent a major explosion.

During harvest, controlling those conditions becomes a continuous operational task rather than a preseason exercise.

Grain Condition Becomes Part of the Equation

Once grain moves into storage, condition management introduces another variable.

Ambrose cautioned in the Purdue report coverage that improper aeration can contribute to fungal growth and smoldering grain, creating a potential ignition source when combustible dust is present. That makes aeration and grain monitoring part of the broader risk picture rather than simply a quality-management consideration.

Grain condition also can influence what employees eventually encounter inside a storage structure. Out-of-condition grain can bridge, adhere to bin walls or develop other flow problems that require intervention.

OSHA identifies engulfment and entrapment as major hazards at grain handling facilities and prohibits employees from walking down grain to make it flow. Before employees enter bins, silos or tanks, mechanical, electrical, hydraulic and pneumatic equipment that could endanger them must be de-energized and prevented from operating. Entry procedures also address atmospheric testing, an outside observer, rescue equipment and protection from engulfment hazards.

These requirements are well established across the grain industry. The challenge during and after harvest is making sure an operational problem does not change the way the work is approached. A plugged system, bridged grain or material that will not flow can create pressure to restore operations. The condition that prompted the work, however, can also be the condition that increases the risk.

Carrying Harvest Practices into Storage

For many elevators, harvest is less a single period than a progression. Grain receipts may slow while drying, conditioning, storage management, loadout and maintenance continue well beyond the busiest receiving days.

Equipment that accumulated hours during harvest may need attention. Dust can remain in less accessible areas, grain condition continues to change in storage, and maintenance or repair work can introduce ignition sources into areas where combustible material remains present.

The 2025 explosion numbers show why the transition matters. Seven incidents represented a decline from the previous year, but their human consequences moved sharply in the opposite direction.

For grain facilities, the takeaway is not that harvest introduces a new set of hazards. It is that the season puts more pressure on the systems already in place to control them. Equipment condition, dust management, grain quality and established entry procedures all become more consequential when operations are running harder and interruptions are harder to absorb. The 2025 explosion data is a reminder that fewer incidents do not necessarily mean less risk. During harvest and the storage period that follows, maintaining those controls is what keeps routine operational pressure from becoming something far more serious.

Sources:

Occupational Safety and Health Administration, Grain Handling Overview and 29 CFR 1910.272, Grain Handling Facilities.

Purdue University Department of Agricultural and Biological Engineering, Agricultural Dust Explosions in 2025, Kingsly Ambrose.

Purdue University College of Agriculture, “Grain dust explosion incidents decrease, fatalities increase,” Olivia De Young, March 17, 2026.