The hidden risks of hay bales in farming

Disclaimer: This content is intended as a general guide only. As an MGA, we’re sharing observations around common risks and practices, not offering farming advice. For detailed guidance on safe baling practices, please click here to view HSE’s best practices.

Across many agribusinesses, hay or straw bales are common, often used for food, bedding, seating, storage and more. While they may seem like a fairly innocuous part of rural life, they can, in fact, bring with them various unseen risks, of which sound mitigation is vital when considering insurance.

While these risks can't be eliminated altogether, it’s important to ensure that they’re understood, well managed and properly underwritten.

This article is designed to help brokers assess and advise on hay or straw related risks and provide clients with practical steps to protect themselves and others.

Hay bales and fire risk

According to industry data, hay and straw stacks present one of the worst fire risks on farms. These stacks are highly combustible and, once ignited, can be near impossible to contain. The financial impact of such fires is often devastating, especially when barns, equipment or livestock are affected.

Every year, 1,700 farm buildings and 66,000 acres of grassland are destroyed by fire in the UK, with about half of farm fires started deliberately. These figures highlight why proper hay storage and fire prevention measures are crucial for any agricultural business. 

What are the most common causes of hay bale fires?

Common causes of fire include:

• ·       Spontaneous combustion
• ·       Arson
• ·       Overlooked fire hazards: hot engines, welding equipment and discarded cigarettes.

How to store hay bales to reduce fire risk

Did you know that even a single haystack can pose a huge threat if it's located too close to buildings, as well as the building they are contained in? That’s why stack placement is so important.

In one example we’ve seen, underwriters intervened when they noticed that a haystack was located closely to a hatchery operation valued at over £6 million, increasing the likelihood and scale of loss in the event of a fire.

When arranging hay and straw storage, insurers tend to look more favourably on setups that reduce fire and arson risks, like keeping stacks well away from high-value buildings, spacing outdoor stacks apart, and avoiding public-facing locations.

How to avoid hay bales spontaneously combusting?

Organic materials stored damp and confined for long periods can self-ignite. Hay is more prone to this than straw, which is typically dry when baled, though straw can still pose a risk if it contains too many green stems.

Bales need to meet critical moisture thresholds before being put into storage to reduce the risk of spontaneous combustion. The quality of damp hay can also be affected when stored, losing nutritional value or potentially developing mould. Smaller bales tend to tolerate slightly higher moisture levels, but regardless, some heating and dry matter loss during storage isn’t uncommon.

It’s also important to regularly monitor their temperature using heat probes. Stored hay can sometimes heat up unexpectedly, especially in the first few weeks and more so in larger stacks with unventilated centres. Farmers should keep an eye on temperatures early on, just to spot any unusual changes. If probe temperatures start climbing, they might shift bales around to vent any heat, but at a certain probe temperature, then they should call the fire brigade and not move the bales. These practices are vital to stay ahead of any potential issues.

For more detailed information on ideal moisture and temperature levels, click here.

How to reduce the likelihood of arson on your farm

Sadly, arson continues to be a driving factor behind farm fires, responsible for around half of all incidents. It’s important to be aware of why this happens. Numerous factors can increase the risk of arson, such as unoccupied or unattended sites or remote haystacks, especially with open access from public roads or footpaths and the presence of easily ignitable materials like hay and straw. Farmers should ideally try to position stacks away from public access points and ideally out of sight of roads, but within view of their farmhouse.

Emergency protocol for hay bale fire

1. Call the fire brigade straight away

2. Don’t attempt to tackle the fire unless it is safe, keep fire fighting equipment maintained and to hand, that will work with your fire emergency plans

3. Give the what3words location to the fire brigade and have the free App on your phone         

4. Ensure someone is ready to direct the fire brigade to the fire

5. Prepare to evacuate livestock if the fire spreads

6. Prepare to use farm machinery to assist the fire brigade

7. Ensure the farm entrance is clearly signed and access kept clear

All farm employees should be familiar with this protocol. Ensure it is reviewed regularly as part of overall farm safety procedures.

Hay bales and crushing injuries

With weights ranging from 100 pounds to a tonne, hay bales can pose serious safety risks if poorly stacked. Farming has seen incidents resulting in severe injuries, including paralysis, amputation and fatalities, which is why it’s important that stacks are built using the recommended stable method for each bale type and monitored over time, as bales can deteriorate.

When used as part of playground-style visitor attractions, extra care is needed to avoid public liability claims. There have been cases of children falling from hay structures, being injured by hidden metal debris, or struck by falling bales from unstable stacks. Anyone considering hay bales as a playground feature should speak to their insurer first and ensure all structures are safely built, supervised and clearly signed.

For stacking, loading, moving and monitoring advice, click here.

Geo’s practical support for policyholders

At Geo, we understand that hay and straw are essential on most farms, so our farm policies cover haystacks as standard when requested.

With that, we also look for ways to help brokers and their clients improve risk management. That's why we've partnered with Merit Advantage to provide clients with discounted access to their Health & Safety app, designed specifically for farming and rural businesses.

The app enables clients to quickly and easily report risks, incidents, and improvements, helping them to stay on top of compliance and reduce the likelihood of serious claims. It’s also useful for tracking haystack inspections, safe stacking practices, and arson prevention measures.

Learn more about the app and how your clients can access the discount here: 

At Geo, we understand that hay and straw are essential on most farms, so our farm policies cover haystacks as standard when requested.

With that, we also look for ways to help brokers and their clients improve risk management. That's why we've partnered with Merit Advantage to provide clients with discounted access to their Health & Safety app, designed specifically for farming and rural businesses.

The app enables clients to quickly and easily report risks, incidents, and improvements, helping them to stay on top of compliance and reduce the likelihood of serious claims. It’s also useful for tracking haystack inspections, safe stacking practices, and arson prevention measures.

Learn more about the app and how your clients can access the discount.

What good looks like

When reviewing farm risks involving hay and straw, brokers should consider:

• Stack limits: You can find more information on appropriate stack limits here
• Fire controls: What measures do your clients have in place to test moisture and temperature? What about inspections, access routes, and electrics?
• Arson prevention: Consider visibility, lighting, fencing, and public access risks.
• Injury risks: Do your clients follow advice around stacking and stack limits, especially in public settings?
• Emergency plans: Are protocols clear and staff trained to respond?

By discussing these risks, brokers play a significant role in helping clients protect their business.