Pig Bang Theory: What's Causing Manure to Explode?

Four words. Hog manure foam explosions. It's a real thing and a real problem for hog farmers in the Midwest. Back in 2009, six industrial-scale hog farms reported blasts from the pits used to capture hog feces. The foam forms as manure breaks down. Toxic fumes are emitted, and gasses like hydrogen sulfide and methane get trapped underneath the layer of foam. Sometimes, this results in explosions.  

Apart from being completely disgusting, it's incredibly dangerous. The methane in the foam is almost always at highly explosive levels, upwards of 60-70% explosive concentration. Manure foam has been reported in Illinois, Iowa, and Minnesota. There have been 25 explosions in Illinois alone from the noxious goop. A large explosion in Iowa leveled one barn, killing all 1,500 pigs and seriously injuring an employee. Sometimes, the foam gets so high it threatens to suffocate livestock. Gross.  

Now for pictures!



Photo(s) via University of Minnesota


Photo via Wired/Charles Claton

What's causing this explosive situation? Microbiologist Bo Hu believes it might have to do with the pig's diet. Distiller's dry grains and soluble's (DDGS) is a byproduct of corn that is added to most swine feed. It has no nutritional value for pigs and is high in unsaturated fatty acids which are present in the foaming mixtures studied by the University of Minnesota. What can stop this pernicious pig foam? Oddly enough, the only thing proven to be effective at all is a popular antibiotic that is traditionally used to make cows grow faster. The antibiotic monensin, notes University of Minnesota's Larry Jacobson has been the only effective tool farmers have found in combating it. Still, no one really knows where foam came from or how it was started. That doesn't bode well for figuring out a way to solve it.

If you really want to get down and dirty with manure, you can learn all about it from this video presentation by university of Iowa researcher David Schmidt: