Farm Insurance 101: What to Do When Your Hay Bales Catch on Fire

| 2024.04.29
Farm insurance 101: What to do when your hay bales catch on fire

In the face of the ever-present risk of hay bale fires, insurance emerges as a critical tool for Canadian farmers to manage uncertainties and protect their livelihoods.

By understanding their coverage options, securing appropriate insurance policies, and partnering with knowledgeable insurance professionals, farmers can effectively mitigate the financial and operational impacts of hay fires.

This article aims to provide a guide on farm insurance and the necessary steps to take if your hay bales catch fire.

Understanding the Science: Why Hay Bales Catch Fire

Hay, seemingly dry and benign, possesses the potential to combust under specific conditions. This phenomenon isn’t a result of magic but rather a complex interplay of biological processes and environmental factors.

Bacterial Activity

Bacteria present in hay thrive in the presence of moisture and glucose, a simple sugar found in plants. As they metabolize glucose through respiration, they produce heat as a byproduct, contributing to the overall temperature rise within the bales.


As the bacterial population grows, so does the internal temperature of the hay bales. This heat, combined with the respiration of the hay plant cells themselves, creates a perfect storm for spontaneous combustion.

Respiration in Plants (Sweating)

Even after harvest, plant cells within the hay remain active and continue to respire, converting glucose into energy, carbon dioxide, and water. This ongoing metabolic activity also generates heat, further elevating the temperature within the bales.

Moisture Threshold

While a certain level of moisture is necessary for bacterial growth and plant respiration, exceeding a moisture content of 15% provides ideal conditions for mesophilic bacteria to thrive. With ample water available, these bacteria multiply rapidly, accelerating heat production within the hay bales.


Bales are compressed so they can be stacked, transported, and stored safely in an enclosed or covered facility. This compaction prevents bales from being able to adequately breathe (or sweat), often for several weeks after harvest. Additionally, bales are stacked and stored to maximize space, which prevents air flow. Due to the nature of storing bales, all other reasoning why bales catch fire is compounded.

Recognizing the Hazards: 3 Prongs of Hay Fire Threats

Recognizing the hazards associated with hay fires is crucial for preventing accidents and minimizing damage. There are three primary prongs of hay fire threats:

1. Flare-ups

When internal temperatures of hay bales escalate to between 150°F and 170°F, the risk of spontaneous combustion intensifies, potentially leading to flare-ups.

While moving hay to facilitate cooling is advisable, caution must be exercised, particularly at higher temperature thresholds where increased oxygen exposure could exacerbate the situation. Exposing hay to increased oxygen can amplify a flare-up. Prompt communication with the local fire department and readiness with charged water hoses are essential preemptive measures.

2. Burned-out cavities

The formation of burned-out cavities within stored hay, resulting from elevated internal temperatures, poses a hidden danger to individuals traversing hay piles. Vigilance is paramount, with at least two personnel advised to investigate hay mows to mitigate the risk of entrapment within these cavities.

3. Toxic gas emissions

Smoldering and burning hay release toxic gasses, including carbon monoxide, with chemically treated hay potentially emitting additional hazardous vapors.

In such instances, summoning trained fire-rescue personnel equipped with self-contained breathing apparatus (SCBA) is imperative to mitigate health risks and ensure the safety of responders and bystanders alike.

Recognizing the Warning Signs

Early detection is critical to preventing hay fires. Farmers should be vigilant for signs indicating elevated internal temperatures within hay bales or stacks. Evaporation, evidenced by steam or condensation on barn surfaces, signals excessive moisture and potential danger.

Unusual odors, resembling tobacco, often accompany mold growth, serving as another warning sign. Regular monitoring of internal temperatures using simple methods like inserting an iron bar into the stack can reveal escalating heat levels. A moisture probe is a cost effective tool to help identify heat and moisture in bales.

Responding to a Hay Fire: Prioritizing Safety and Strategic Actions

In the event of a hay fire or smoldering, immediate contact with the fire department is paramount, with human life taking precedence over all other considerations. Before engaging in firefighting efforts, farmers should undertake a series of preparatory actions to enhance safety and assist emergency responders:

1. Prioritize human life

Contact emergency services immediately, prioritizing human safety above all else. Material possessions can be replaced, but lives cannot.

2. Pre-firefighting preparations

Before firefighters arrive, undertake essential preparatory measures, including the following:

  • Accounting for all personnel.
  • Identifying and notifying firefighters of any flammable products present.
  • Assessing the need to shut off electricity in affected buildings.
  • Considering livestock safety when relocating animals from structures housing hay fires.

3. Clear the area

Remove extraneous vehicles and machinery from the vicinity of the fire to facilitate access to firefighting equipment.

4. Equip for action

Position bale-moving machinery strategically for effective fire response, ensuring readiness to assist firefighters as directed.

5. Access material safety data sheets (MSDSs)

Retrieve material safety data sheets for any chemical preservatives used on hay, facilitating informed firefighting procedures.

6. Monitor personnel health

Recognize the physical toll of firefighting efforts, prioritizing the health and well-being of individuals involved. Prompt medical attention should be provided for any signs of distress.

Key Precautions and Preventive Measures

Farmers can mitigate hay fire risks by adhering to key precautions and preventive measures:

  • Moisture management: Hay fires are most prevalent within the first six weeks after baling, emphasizing the importance of maintaining moisture levels at 20% or less during baling.
  • Storage practices: Keep baled hay dry by storing it indoors or covering it adequately when stored outdoors.
  • Temperature monitoring: Regularly monitor internal bale temperatures to detect any signs of overheating or combustion.
  • Safety protocols: Delegate temperature-checking tasks to experienced personnel, avoiding assigning such responsibilities to youth workers.
  • Ventilation strategies: Adjust ventilation based on hay temperature, ensuring proper airflow without risking fire escalation.
  • Tracking: Keep records of bale moisture & temperature to help determine what direction the bales are trending.

Insurance Coverage for Hay Bale Fires

Understanding the nuances of insurance coverage for hay bale fires is critical for ensuring adequate protection against financial losses. Here are some key considerations to keep in mind when evaluating your insurance policy:

Property Damage Coverage

When hay bales catch fire, property damage can be extensive. Farm insurance typically covers structures like barns, storage facilities, and equipment damaged by fire. This coverage ensures the replacement or repair of affected structures, minimizing disruption to farming operations.

Crop Loss Coverage

Hay fires often result in significant crop loss, impacting current and future harvests. Farm insurance policies commonly include provisions for crop loss due to fire, compensating farmers for the value of damaged hay. This coverage helps mitigate financial losses and facilitates quick recovery.

Liability Protection

Hay fires may pose liability risks for farmers, potentially leading to legal claims and expenses if the fire spreads or causes injury. Farm insurance provides liability protection, covering legal costs and damages awarded in lawsuits arising from hay fires.


Understand any deductibles applicable to fire-related claims in your farm insurance policy. Deductibles represent the portion of the loss you’re responsible for covering out of pocket before insurance coverage kicks in. Knowing the costs beforehand might help you plan and manage your financial risk more efficiently.


Review policy exclusions to identify circumstances not covered by your insurance. Common exclusions include deliberate arson or negligence. Awareness of these limitations helps mitigate risks and minimize potential losses.

Additional Coverage Options

Consider whether additional coverage options, such as livestock mortality insurance or business interruption insurance, are necessary to protect your farm against the financial consequences of hay bale fires.

Farm Insurance: Final Insights

In the aftermath of a hay bale fire, the financial repercussions can be significant. Understanding your farm insurance coverage is essential for navigating the aftermath and mitigating financial losses.

Policies typically cover fire damage to hay bales, but insurance limitations, deductibles, and exclusions may differ. Reviewing your insurance policy to ensure adequate coverage and exploring additional options can provide added protection against unforeseen circumstances.

Partner With the Farm Insurance Specialists at MMI Insurance

At MMI Insurance, we understand the unique challenges farmers face in protecting their agricultural assets. For inquiries regarding farm insurance, including coverage for baled hay, contact us at 1‑866‑222‑6996.

With the support of our insurance advisors, farmers can navigate the complexities of farm insurance with confidence, thus ensuring peace of mind amidst potential hazards.