Earlier this month, three brothers died from asphyxiation while working on a pump at a manure pit on an Ohio farm. All three were in their 30s and reported to be lifelong farmers. Firefighters found all three unresponsive. The brothers were transported to two hospitals.
As far back as 1990, NIOSH recognized the dangers of manure pits. In an alert from that year, NIOSH said it was unclear how many of the livestock farms in the United States used manure pits. These concrete-lined pits are typically connected by underground channels to livestock containment buildings; they collect waste and use anaerobic digestive fermentation to convert the manure into fertilizer.
This process generates methane, hydrogen sulfide, carbon dioxide and ammonia. These gasses in the confined space of the pump area or pit can create oxygen deficient, toxic and explosive environments. According to the CDC, manure-pit incidents are most prevalent in August when the weather is warmest, which increases the bacterial fermentation and the amount of gasses produced.
Hydrogen sulfide is the most concerning of the gasses. Because it is heavier than air, it sits near the bottom of the pit. In high concentrations, it can cause death in minutes. It also has an explosive range from 4.3% to 46% concentration in air. Methane, which is lighter than air, is explosive at concentrations between 5% and 15%. At both the upper and lower levels of the pump area and pit, oxygen depletion and explosion are real dangers.
These incidents often result in multiple fatalities when potential rescuers become victims. It is unclear if that was the case in Ohio this month. News reports say the three brothers were performing maintenance on the pump when tragedy struck.
The Bellefontaine Examiner reported that two fire departments, one dive team, three EMS providers and two law enforcement agencies responded to the St. Henry, Ohio emergency. Local media reports did not indicate that hazmat teams were called or that any responders were taken ill during the rescue operation.
Most agriculture rescue operations involve machinery or grain silo entrapments. Yet manure pits need to be understood and trained on given how deadly they can be. Here are three lessons hazmat leaders can take from the Ohio tragedy and other similar fatalities.
Educate and train local firefighters in rural settings on these dangers. In more rural, agricultural areas, a hazmat team may not be close at hand. This puts the onus on those first on scene to make a rescue without becoming additional victims. At the minimum, hands-on hazmat training should be conducted once per year with rural departments — preferably in late spring or early summer so the training is fresh in their minds as they enter the peak season for these incidents. Devices like HazSim are an effective way to do this hands-on training without needing a lot of props.
Have initial response protocols that focus on rescuer safety. Dispatch should remind police to keep themselves and Samaritan rescuers clear of these pump tanks and pits if they are first on scene. Local firefighters need to be proficient in monitoring these confined spaces for oxygen levels and explosive limits. This means identifying those locations within a jurisdiction in pre-incident plans and sharing that information with dispatch and emergency response partners. Incorporate confined-space best practices into those protocols.
Be aware of the air. Wearing SCBA is a must. Monitoring equipment can fail or be out of calibration; back-up equipment may not be available in more rural settings to confirm initial readings. And where hydrogen sulfide is concerned, the sense of smell cannot be trusted. At only 150 ppm, hydrogen sulfide paralyzes the olfactory nerves — negating the ability to smell the gas.
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