Stay safe: Protect yourself from the dangers of pit gases

By Dr. Leah Gesing

During the past few months, tragedy has struck two farm families in Iowa and Wisconsin.  Two father-son pairs were killed when they were overcome by pit fumes while working in a pig barn.  These tragic events serve as a reminder of the need to frequently educate all people involved in the management of pigs and manure.  Make sure your team understands the characteristics of pit gases and ways to work safely around stored manure.

The gases present in the greatest volume in stored manure are ammonia, methane, carbon dioxide and hydrogen sulfide.

Ammonia is lighter than air, so it generally dissipates from well-ventilated barns.  High enough ammonia levels can be irritating to the nose and throat and cause respiratory distress.  However, ammonia will not accumulate to lethal levels in a barn.

Although methane is non-toxic to humans and animals, it is well known for its highly explosive and flammable properties.  Methane has no odor.  It is lighter than air so, like ammonia, it generally dissipates from well-ventilated pig buildings.  Even a small spark, however, can cause an explosion in a poorly-ventilated facility.

Carbon dioxide is produced by stored manure, animal respiration and the burning of heating fuels.  It is odorless and toxic at levels exceeding 70,000 ppm.  If ventilation fails, death can occur through asphyxiation in a matter of hours.

The deadliest gas present in stored manure is hydrogen sulfide.  Hydrogen sulfide is highly lethal at high concentrations.  At concentrations greater than 600 ppm, hydrogen sulfide can kill an individual after only one or two breaths.  Further adding to the very dangerous aspects of this gas, at levels higher than 500 ppb, hydrogen sulfide is undetectable by smell.

Both hydrogen sulfide and carbon dioxide are heavier than air and tend to collect at the manure surface.  Both of these gases are soluble in the liquid portion of manure and are instantly released into the air when the liquid is stirred.  Therefore, actions such as something dropping into the pit or manure agitation will cause the release of these gases.

Below are some guidelines to work safely in the presence of or when handling stored manure:

• Watch for the presence of foam on the pit surface.  Foam can trap all four main pit gases and will contain about 60 percent methane.  The methane in foam can be highly explosive if it is suddenly released by an activity such pressure-washing or agitation.
• Always keep the ventilation system on and in working order whether pigs are in the building or not.  Ventilation is a must when performing any type of mechanical or electrical work.
• Ensure that no one enters the building when agitating manure.  Stay out for 30 minutes after pumping has ended.  Post “No Entry” signs at all entry points.
• Fully open all ventilation curtains or ventilation pivot doors until at least 30 minutes after pumping has ended.
• Turn off heater pilot lights and other non-ventilation electrical systems when agitating and power-washing barns.
• Always make sure that pit agitation occurs below the liquid surface and that pressurized manure does not strike walls or columns.
• NEVER enter the pit area unless you are wearing a self-contained breathing apparatus (access more information on these devices by clicking here).

Click here for much more information about the dangers of pit gases or ask your Vita Plus consultant for more information.

The Vita Plus Swine Nutrition team wants to ensure that you and everyone involved on your farm operation are well informed about working safely around stored manure.

About the author:  Dr. Leah Gesing is a Vita Plus swine technical sales and support specialist.  She earned her bachelor’s degree in animal science from Iowa State University.  She continued there to earn her master’s degree in animal physiology, studying on-farm factors affecting market hog transport losses.  She then went on to the University of Illinois to earn her Ph.D. in animal sciences.  While in school, Gesing was involved with numerous research projects, teaching experiences, internships, and international travel.  Specifically, she conducted applied research in swine genetics, health, management and reproduction with Dr. Mike Ellis.  Her Ph.D. project evaluated the effect of timing of OvuGel® administration on reproductive performance in gilts synchronized for estrus.