When you breathe in dust from moldy hay, grain, or other farm materials, you might be at risk for farmer's lung, a type of allergic lung disease triggered by inhaling mold spores in agricultural settings. Also known as hypersensitivity pneumonitis, it’s not an infection—it’s your immune system overreacting to something in the air you breathe every day. This isn’t rare. In farming communities, it’s one of the most common work-related lung diseases, especially in places where crops are stored damp or poorly ventilated.
Mold exposure, specifically from thermophilic actinomycetes like Micropolyspora faeni and Thermoactinomyces vulgaris is the main culprit. These microbes grow in damp hay, straw, silage, and grain—materials that seem harmless until they start to rot. When you handle or disturb them, tiny spores float into the air. Breathing them in day after day can slowly scar your lungs. You might not feel anything at first. But over time, you’ll start coughing, feel tightness in your chest, get feverish after work, and notice you’re winded even walking up stairs. These aren’t just allergies—they’re signs your lungs are being damaged.
People who work with livestock, in grain silos, or handle stored crops are most at risk. But it’s not just farmers. People working in animal barns, mushroom farms, or even woodworking shops with moldy wood can develop similar reactions. The key difference? Occupational lung disease, a category that includes farmer’s lung, asbestosis, and black lung—these conditions show up because of what you’re exposed to on the job. And unlike a cold, they don’t go away when you stop working. Once your lungs are scarred, the damage is often permanent.
There’s no magic pill to fix it. The only proven way to stop it is to avoid the dust. That means drying crops properly, using ventilation, wearing respirators rated for organic dust, and keeping storage areas clean. Some people think masks are overkill, but if you’re around moldy hay every day, a simple dust mask won’t cut it. You need an N95 or better. And if you’re already having symptoms—coughing after work, feeling tired, short of breath—don’t wait. Get checked. A chest X-ray and lung function test can catch it early.
What you’ll find below are real, practical articles from people who’ve lived this. You’ll read about how to recognize the early signs, what tests doctors actually use, and how to protect yourself without quitting your job. There’s advice on respirators that work, how to tell if your barn is a risk, and what to do if your symptoms keep coming back. These aren’t theory pieces—they’re based on what works in the field, in the clinic, and in people’s lives.
Hypersensitivity pneumonitis causes cough and breathlessness from inhaled environmental triggers like bird droppings or mold-not medications. Early diagnosis and avoiding the trigger can prevent permanent lung damage.