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Mold Remediation in Farm Buildings

Mold grows wherever moisture lingers, and farm buildings offer plenty of damp places. Cleanup can expose people to spores, so it helps to plan before you start.

Why does mold matter on a farm?

Mold grows on wet or damp organic material such as hay, silage, grain, bedding, wood and drywall. In farm buildings it can spread after a leak, a flood or a period of high humidity, and it can damage materials as well as affect health.

Breathing in spores or dust from moldy material can cause coughing, wheezing and other symptoms, and can be more serious for people with asthma, allergies or weak immune systems. Some farm workers develop lung conditions linked to repeated exposure to moldy dust. Dust from moldy hay or grain can also carry bacteria, so the exposure is not only from the mold itself. That is one reason to treat moldy feed handling as a health issue and not just a housekeeping one.

What are the signs of mold problems?

Mold is not always visible. Use your eyes and nose, and look for causes of moisture.

• Musty smells that linger
• Stains, fuzzy growth or discoloration on surfaces
• Condensation and damp walls or ceilings
• Leaks, standing water and flooded areas
• Workers coughing or having itchy eyes in a building
• Moldy hay, feed or bedding that heats or clumps

What comes first: moisture control or cleanup?

Stopping the source of water is the first job. If you clean without fixing the leak, the mold will return. Look for roof leaks, plumbing problems, poor drainage, humid air and condensation.

Dry wet materials promptly where they can be saved, and remove those that cannot be dried. Ask your Extension office or local health department about how quickly materials need attention after a flood or leak. Insulation, drywall and wood paneling soaked for a long time may need to be removed. Concrete and metal surfaces can often be cleaned, but ask an expert what suits your materials.

Who should do the cleanup?

Small areas may be handled by trained workers using proper methods and protective equipment, but larger or more serious cases may need professionals. Cleanup stirs up spores and dust, which is exactly the exposure you want to limit.

Do not decide on respirators, protective clothing or cleaning agents from memory. Choice and fit are set by official guidance and need training. Ask OSHA, NIOSH, AgriSafe or an occupational health provider, and do not mix cleaning chemicals. Wet cleaning methods that keep dust down are generally preferred over dry sweeping or blowing, which fills the air with spores. Confirm the best method for your situation with an official source.

What about moldy feed, hay and grain?

Moldy feed and stored crops can affect animal health and may contain toxins. Do not feed suspect material without advice, and do not dig into or enter bins and silos that contain it. Enclosed storage can have dangerous conditions.

Ask your veterinarian, nutrition adviser or Extension specialist how to evaluate and dispose of suspect feed. Disposal rules vary by state and county, so check with the proper agency. If someone becomes ill after breathing dust, they should get fresh air and medical care, and 911 should be called for serious breathing trouble.

How do I prevent mold from returning?

Prevention is mostly moisture control. Fix leaks quickly, keep drainage moving away from buildings, vent damp spaces, store feed dry and rotate stock. Keep an eye on humidity in sealed rooms.

Include mold in regular building checks, especially after storms or in humid seasons. Keep records of repairs and cleanup so you can see patterns. A written schedule of when each building will be inspected, and who is responsible, helps keep the work from being forgotten during busy seasons.

• Fix leaks quickly
• Store feed and bedding dry
• Ventilate damp rooms
• Check after storms and floods
• Keep records of repairs

How do I look after worker health?

Tell workers what you are doing and why, and let them say if they feel unwell. People who have breathing conditions should talk to their health provider before taking on cleanup.

If symptoms persist or worsen, ask a doctor and mention farm exposures. AgriSafe Network focuses on agricultural health and may offer education and referrals. Family members who live close to affected buildings should also be told, particularly if they have asthma or other conditions. Consider keeping a simple log of dates, locations and findings so that patterns, such as a seasonal rise in the fall when rodents seek warmth, become clear and you can plan ahead.

Last reviewed: November 12, 2026. Written by the Farm Safety Editorial Team. See our editorial policy.