Some safety hazards are easier to spot than others, such as a moving tractor, an auger, or a large animal. Most farmers know how to work safely around these things. But what about hazardous gases?

“Much of what you find on the farm is organic. And organic products break down and decompose, animals produce manure, all of which can create gases,” explains Ryan Dick, Health and Safety Consultant with Workplace Safety & Prevention Services. “So, it’s not only the chemical pesticides and herbicides that you need to be aware of. Silo gas and manure gas are invisible, odourless, and can be just as deadly.”

Where are the risks?

While the risks of inhaling chemical pesticides and herbicides are listed on WHMIS labels and safety data sheets, that’s not the case for the gases produced by organic materials, such as silage. Silage—made up of grass, corn, maize, and other plants—is often stored in a silo to ferment. Silo gas, which contains carbon dioxide and nitrogen dioxide, is produced during the fermentation process, depending on the style of silo. “The gas displaces oxygen within the silo. So, if a farm worker goes into that silo for any reason, they won’t be able to breathe for long,” says Ryan. 

“Workers need to be aware of this potential hazard and understand that if someone collapses after going into a silo, they can’t run in after them,” says Ryan. “Not without the proper personal protective equipment, such as a self-contained breathing apparatus.”

Manure lagoons are another source of potentially hazardous gas. They produce fumes and odours, but out in the open air, they are not likely to pose a risk to workers. “However, some farms have digesters, so there’s a covered container. Farm workers need to be aware of the potential gas exposure before working with digesters,” says Ryan. Anyone using liquid manure tankers around the farm should also exercise caution, particularly if they bring the tanker into a shop, garage, or other enclosed space.

Methane or ammonia buildups are other situations farmers need to avoid. Barns usually have adequate ventilation to dilute the methane and ammonia produced by animals. However, when a storm comes and all the animals are corralled inside with the windows and doors closed tightly, the ventilation may no longer be adequate. “Especially if snow drifts are blocking vented areas or a prolonged power outage occurs,” Ryan points out. 

7 ways to minimize exposure to hazardous gases

Whether it’s a silo, a barn, a chemical storage room or a garage, ventilation is one of the best ways to prevent asphyxiation from hazardous gases. If you can’t eliminate the gas, which would be the best option, adequate ventilation is very important. “Always make sure you have enough vents and windows and inspect them to confirm they are in good working order,” reminds Ryan.  Ceiling fans can be effective ways to help draw the gas up and help airflow, but they do not offer proper venting for controlled airflow conditions. If you are running vehicles or heavy equipment indoors (e.g., in a shop), hook them up to an exhaust vent to maintain good air quality in the work area.

Ryan offers these tips to prevent exposure to hazardous gases.

1. Provide WHMIS training to everyone who works on the farm. This includes family members as well as paid employees. Training on Workplace Hazardous Material Information System (WHMIS) labels and safety data sheets (SDS) is critical for anyone working with or near chemicals so that they understand the risks of handling a specific chemical and how to protect themselves.
2. Tell farm workers where they may encounter hazardous gases. Working conditions on farms are changing constantly. Regularly communicate with workers about where they may come across hazardous gases and have a plan in place in case someone collapses from exposure.
3. Follow the recommendations on soil analysis reports. Monitor the nitrogen and nutrients added to crops during the growing season. This will have an impact on the production of silo gas during fermentation. “The healthier the plants are, the better,” says Ryan.
4. Do not enter a silo for four to six weeks after it has been filled. This avoids exposure to silo gas. If opening the silo for feeding, especially within the first two weeks, consider having workers wear appropriate self-contained breathing apparatuses.
5. Post warning signs and do not work alone where hazardous gases may be present (e.g., chemical storage areas).  Ensure someone else is nearby and can take action with the proper personal protective equipment. “A check-in procedure doesn’t really work in these situations because the damage is done within minutes,” notes Ryan. “By the time you miss a check-in, and another worker realizes what has happened, it’s already too late.”
6.  Ensure proper ventilation fans are installed in barns, silos, garages, and chemical storage areas. “Run venting fans for at least several minutes before going in,” says Ryan.
7. Make self-contained breathing apparatus available to farm workers. Train them on how to use them, when to use them, and how to properly maintain them. 

How WSPS can help

Consulting

WSPS’ agriculture health and safety experts can help you improve your health and safety program and control exposure to hazardous gases on your farm.

Training

• WHMIS for Workers (virtual, instructor-led, 3.5 hours)
• WHMIS Online Training (1.5 hours)
• Hazard and Risk: Identify, Assess, Control, and Evaluate (eCourse, 3 hours)

Resources

• Agriculture Safety Resources in Multiple Languages
• Farm Safety Roundup Podcast

 The information in this article is accurate as of its publication date.