Jason Ertl

The annual fall harvest is well underway in many parts of the upper Midwest with corn, soybeans and other row crops moving from the field to the grain bin or elevator. Crop yield, hog prices, weather and other operation-related logistics will occupy the mind of every producer.  During this busy time of year however, the absence of one key element on the farm can quickly turn a successful season into tragedy. The failure to recognize important safety measures — especially those associated with manure pits and their safety hazards — can endanger the lives of humans and animals alike, which make safety the top priority to everyone working on the farm.

Dangerous gases from below

The breakdown of manure in pits produces gases like carbon dioxide, hydrogen sulfide and methane. Pit pumping and agitation can release these gases and increase their airborne concentration, which can pose a safety threat to those inside the barn or in close proximity due to their toxic, oxygen-deficient and/or explosive nature. These gases can be odorless, colorless and may cause serious health effects even during short periods of exposure.

For example, concentrations of hydrogen sulfide, at 600 parts per million, can kill an individual after only one or two breaths. Because of this rapid lethalness, there have been several cases in the past where multiple farmers died in an attempt to rescue a succumbed individual from a manure pit.

High concentrations can also occur at different times of the agitation or pumping process. Aggressive agitation at the beginning, at the end, or when an agitation jet is positioned above the surface of the manure can break the crust formed on the top of the stored manure leading to spikes in gas concentrations. In addition to these hazards, methane trapped in manure pit foam can pose as a threat as well, where sparks from electrical equipment or welders can ignite and cause catastrophic damage.

Tips and recommendations for human and animal safety

There are a number of different precautions producers and manure handlers can take to reduce the risk of toxic, oxygen-deficient and/or explosive gas exposure.

Like any other type of confined space, manure pits must be ventilated to reduce the risk of gas buildup. Ventilation fans should be checked regularly as part of the farm’s standard operating procedure, as well as prior to pumping or agitation. Whether the barn is tunnel ventilated or curtain sided, ensure that all necessary fans are operating at 100 percent to maintain proper air movement and recycling. 

There are almost yearly reports where a fatality has occurred after someone enters a facility or manure pit during pumping or agitation. Personnel — both on-farm and manure handlers — should never enter the building at this time. Entrances and exits should be clearly marked with a cautionary indicator of the pumping or agitation in progress. Producers can contact a PQA Plus advisor or visit pork.org to obtain these warning tags which are available in both English and Spanish. 

If used correctly, commercially-available gas and oxygen testing meters can provide readings about gas levels within or surrounding manure handling facilities. There are three types of devices: detector tubes, dosimeter tubes and solid state detectors. Detector and dosimeter tubes are gas sampling devices that give reliable readings for the different toxic gases found on the farm and are an inexpensive alternative to solid-state detectors. Solid-state detectors, which feature a continuous monitoring and audible alarm system, are more costly upfront and require more frequent calibration. 

Farm workers and manure handlers should understand and recognize the symptoms associated with toxic gas exposure. It is important to note that while being adequate in their ability to filter out particulate matter, dust masks or other cartridge respirators do not filter out toxic gases commonly found in manure pits. Persistent cough, shortness of breath, dizziness, episodes of flu-like illness (including nausea, headache, muscle aches and fatigue) are all indicators of acute exposure. Individuals experiencing these symptoms need to seek medical attention.  Animals inside the barn may also exhibit symptoms of gas exposure. Pigs experiencing high concentrations of ammonia, for example, will have watery eyes and difficulty breathing. Increasing the ventilation in the barn will be necessary to improve air quality.   

Farmers and manure handlers should be familiar with the facility’s Emergency Action Plan. In the event of an emergency, time cannot be wasted and the EAP will have important contact information such as the local fire, sheriff and rescue departments. Other helpful contacts to include on an EAP could be the site veterinarian, electrician and poison control officer. GPS coordinates or driving directions to the site are important, as first responders may experience difficulty in navigating to rural locations.

Don’t forget about biosecurity

Producers and manure haulers must be in communication with each other before, during and after the pumping process in order to reduce the possibility of disease movement. Recent outbreaks of highly contagious pathogens, like PEDV, have underlined the importance and necessity to maintain and follow a strict biosecurity protocol. Research has shown that PEDV can live in manure slurry up to 14 days at 77 F and more than 28 days at minus 4 F, so it is especially important that farm workers and manure haulers follow these biosecurity guidelines to reduce the risk of cross contamination between sites.

Before manure haulers arrive, they should exchange contact information with farm personnel, have a record of previously pumped sites and be familiar with the farm’s biosecurity protocol and line of separation. The line of separation defines the segregated working areas between farm staff and the manure haulers. If either group crosses this line, they will need to repeat the farm’s entry protocol before returning to their respective work zone. 

During the pumping and agitating procedure, it is vitally important to maintain this line separation. Manure handlers should be wearing clean coveralls, boots, gloves etc. They need to avoid entering the facility or other buildings and avoid contact with farm personnel or animals.

After manure pumping and hauling is complete, it is good practice for haulers to inform the producer of any spills or biosecurity breaches that may have occurred during the process.  Cleaning, disinfecting and drying the equipment and vehicles — as well as changing out of dirty clothes — is also a must before leaving the farm.

Protecting yourself, your crew and your animals is the most important factor in a successful harvest season. The ability to identify and prepare for the potential threats to health and well-being is something we must continuously prioritize and improve upon.  

Jason Ertl is an Extension Educator specializing in ag production systems in Nicollet and Sibley Counties. His e-mail address is ertlx019@umn.edu.