Confined Spaces Hold Seen and Unseen Dangers

As National Farm Safety & Health Week continues, see why it’s important to have a rescue plan in place before entering a silo, grain bin, manure pit, or other confined space.

Just hearing the phrase “confined spaces” is enough to send anyone with claustrophobia into a panic. Regardless of how farmers feel about being in tight spaces, however, sometimes it comes with the territory. It’s wise to come up with a safety protocol for working in these conditions before the need arises.

The Occupational Safety and Health Administration (OSHA) defines a confined space as one that is large enough for a person to enter and perform work, but has limited or restricted means for entry or exit and is not designed for someone to be in continually. Examples include an upright silo, manure pump reception pit, and grain bin.

The USDA lists four major dangers for working in confined spaces on the farm: chemicals or gases may displace or consume oxygen, so there may not be enough oxygen to breathe; fires and explosions can happen more easily; toxins in the air can damage the respiratory and nervous systems and even cause death; and physical dangers from moving parts or falls can suffocate or crush a worker.

The USDA recommends identifying confined spaces on your farm and taking steps to prevent accidental entry. Workers who do enter must receive specific training and have a permit to enter. When entering a confined space, workers should:

  • Test the air: Test for oxygen, flammability, and toxicity every 4 feet and in corners.
  • Wear proper equipment: Use the correct respirator and make sure all equipment is tested and grounded.
  • Cut off gas, power, steam, and water lines: Follow lock-out procedures to avoid accidental start-up of equipment, and disconnect and cap all input lines.
  • Use the buddy system: Have at least one trained and equipped coworker standing by in case there’s trouble. Decide ahead of time how to communicate.
  • Remove fire hazards: Use spark-proof tools, lights, and fans.
  • Wear a lifeline: A harness and attached lifeline is key for performing a rescue. Simply putting a rope around the waist isn’t enough. Have ladders and lifts available.
  • Removing a coworker: If a worker must be rescued, never go in after him or her unless another trained and equipped worker is there. Have trained rescuers on standby.

These resources from Successful Farming offer more in-depth information on safety in enclosed work spaces:

Unseen Dangers

Examining the physical stability of the structure to avoid entrapment is probably the first thing most people would consider before getting into a confined space, but the dangers that can’t be seen can cause just as much harm. When entering a manure pit, silo, grain bin, or any building with poor ventilation, a person can be overcome by gases or dust, causing permant lung damage or even death.

The most common dangerous gases on the farm are hydrogen sulfide, ammonia, and carbon dioxide. Hydrogen sulfide is formed when manure decomposes. It has a distinctive rotten-egg smell, but the odor disappears the longer a person is exposed, often creating a false sense of security. In low concentrations, it can cause headaches and nausea; in high concentrations, it is combustible and can suffocate a person. Ammonia, which also has a distinctive odor, can cause eye ulceration, respiratory system irritation, and suffocation. Carbon dioxide is produced during decomposition and respiration of plant materials, and it’s extremely dangerous because it is colorless and odorless. At low levels, it may cause headaches and drowsiness; at levels of 30% or greater, it may cause death by suffocation.

Dusts are also a common hazard on the farm. Breathing dust from moldy forage or feed can lead to Farmer’s Lung, a permanent condition that is often mistaken for bronchitis or pneumonia, but which can cause irreversible lung damage and sometimes death. Less noxious dusts can also decrease lung capacity and cause those exposed to be more susceptible to respiratory infections. Smoking makes the damage even worse.

In order to reduce the risk of lung damage or death, farmers should avoid mold by storing only dry grain and well-cured forages and hay, keeping livestock areas as clean as possible, and wearing disposable dust masks or filter masks. When working in silos, manure pits, and other areas with depleted oxygen, a self-contained breathing apparatus should be used.

Learn more about preventing respiratory illness and death:


The third week in September is recognized as National Farm Safety & Health Week. The National Safety Council and the National Education Center for Agricultural Safety head up the effort to develop and disseminate educational materials leading up to and throughout the week.

This year, the theme of National Farm Safety & Health Week is Shift Farm Safety Into High Gear. Monday, the focus was on tractor and rural roadway safety, Tuesday was opioid addiction and suicide, and Wednesday was farm safety for kids. Friday will focus on safety and health for women in agriculture. Webinars on these topics are available through a partnership with AgriSafe at The webinars are free but do require a free AgriSafe account.

More information on National Farm Safety & Health Week, including several safety videos, is available at

National Farm Safety & Health Week 2019
Monday: Brush up on Rural Roadway Safety
Tuesday: Watch for Addiction, Suicide Warning Signs
Wednesday: Keep an Eye on Kids This Week and Every Week

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