Poisonous pits hold their secrets
|Like the sudden strike of a poisonous snake lurking in the grass, poisonous pit gases are not really predictable; especially when agitated. Photo by Dieter Krieg|
By DIETER KRIEG
Brownstown, Pa. -- It's a well-known fact that manure pits produce deadly gases; but identifying the agents and conditions that can make them extraordinarily lethal is not as easy as one might think. That's the word from scientists and others studying the ugly, sinister subject.
Meanwhile, reports of deaths or near deaths, continue; in part because the gaseous chemistry within a pit can change suddenly, affected by composition, temperature and even wind. A thousand "safe" exposures at the pit's edge may have been trouble-free; but there's never a guarantee that the next exposure won't claim someone's life. Perhaps even several lives.
Like the sudden strike of a poisonous snake lurking in the grass, poisonous pit gases are not really predictable; especially when agitated. Researchers are finding bits of pieces of the puzzle but are also discovering how much they really don't know.
“The emission of H2S (hydrogen sulfide) from manure storage is a complicated and poorly understood phenomenon,” admitted researchers in a paper titled “Air emissions from animal feeding operations.”
Hydrogen sulfide is known to be the most lethal of manure gases, all the more so because its formation and release are a “poorly understood phenomenon.”
Numerous manure-related fatalities in recent years have brought profound grief to a wide circle of families and friends, not to mention entire communities. Each time, the strong suspicion is that the victims were overcome by gas before drowning in the "quicksludge" which is even more unforgiving than quicksand. Once you're in; you're not likely to get out. Not even with help ... because the same gas that struck the first victim will claim the rescuers as well.
Such tragedies are on the rise, hurried along by the changing patterns in dairying, including larger herds, altered nutrition, manure storage and accompanying environmental concerns. And along with all that, there are plenty of unknowns and possibly also the mindset that "it can't happen to me."
An overly confident attitude has claimed many a finger, hand, arm, leg, or even an entire body during the corn-picking season. With known, visible and even tangible dangers such as corn pickers snatching lives each year, it stands to reason that an unseen and silent killer such as poisonous gas can be "overlooked" to say the least. Fatalities have been documented every year since 1975, which coincides with the dramatic rise in manure storage systems.
While manure gases are nothing new; it's their concentrations and "enhanced" chemistry -- thanks to modern livestock practices -- that is behind the tragedies. Everything from feedstuffs to bedding materials, and milk house wastes to storage architecture has contributed to increased concentrations and occurrences of lethal manure gases. One product that's been held in suspicion for decades -- beginning in Europe, and in more recent years also in the U.S. -- is gypsum. But, again, thanks in part to the extreme and murky complexities of the issue, new studies are seeing little actual proof of it. In fact, some studies suggest that the opposite may be true.
Research conducted by the University of Wisconsin found that gypsum improved barn air quality by tying up ammonia in manure, stayed in suspension in slurry tanks and pits and did not compromise manure pumps. “Wallboard (gypsum) can work successfully as a bulking agent, absorbing excess moisture, reducing odor and adding calcium, sulfur and carbon to the bedding mixture,” the researchers concluded.
In the maritime provinces of Canada, researchers noted:
“The disposal of waste wallboard at landfills can lead to anaerobic conditions which allow bacteria to release noxious hydrogen sulfide gases. It is important to test for the potential release of hydrogen sulfide in bedding due to direct animal exposure. Low levels can lead to irritation of respiratory systems. Hydrogen sulfide gas was not detectable in either the compost dairy barn or the free-stall barn.”
Terry Weaver, president of USA Gypsum, based in Reinholds, Lancaster County, Pa., emphasizes the need for safety, regardless of what’s in or not in the pit. The notion that “if I’m not using gypsum, I don’t have to be worried,” concerns Weaver, whose company was nationally recognized with the Green Small Business Award in 2012.
“The safety issue is not being seriously addressed,” Weaver affirmed. That’s why he personally as well as his company, allied with Penn State University, the Pennsylvania State Conservation Commission and Industrial Scientific Corporation are now spearheading research efforts aimed at making manure storage and handling activities safer. Learning more about the complex, volatile chemistry surrounding manure pits is a start. Educating the farm community about the gaseous dangers and the contributing factors is the non-stop goal.
Ag colleges across the country have taken on the challenge of exploring the deadly mix, from the murky depths of manure pits to the foul air around them. Among their findings is that dried distillers grains (DDGs) may be a contributing factor to the increasing dangers around manure storage facilities. DDGs are being included in livestock rations at greater concentrations than ever before, due to more of them being produced as a byproduct of the expanding ethanol industry.
In the pit, the excreted DDGs are now being suspected of accelerating the formation of hydrogen sulfide gas. But hard proof is hard to come by because of the ever-changing dynamics. In Minnesota, for example, scientist Chuck Clanton wrote: “We would hear from one producer with three barns that one is foaming and the other two aren’t. We’d start to try to identify the differences, but it’s the same pigs, the same feed, the same genetics, management and building. Everything’s the same.”
Clanton’s mission to solve the mystery had gone into overdrive when some hog barns were exploding across the Midwest in 2009 while others had deadly foam blooming through slatted floors from the pits below.
“We thought, maybe naively, that we could find some obvious commonality,” declared Canton’s research associate, Larry Jacobsen. “We’d do some simple lab analysis and something would jump out to trace it back to a cause. But we couldn’t.”
Weaver, recognizing the dilemma as well as anyone, says:
“The safety issue is what we have to keep coming back to. The industry has to get it right. We need to treat that pit with respect. Safety first!” he pleaded.
In the meantime, he hopes two things will come out of the efforts thus far:
1. No further incidents of deaths or injuries around manure storage areas.
2. Get a better understanding of the chemistry in and around manure pits and use that information to reduce risks.