Since 2009, six hog farms have exploded from a strange new substance that builds up in manure pits. Thick, brown foam covers the tops of manure pits and traps methane gas. When the foam is disturbed, large amounts of methane are released at one time, making a large risk for explosions. The strange thing is, the appearance of this foam has only happened in the past few years, and no one really knows why.
The unusual foam can be found in the manure pits of about 1 in 4 hog farms, and is described as “melted brown Nerf”. Scientists think the formation of this foam may be caused by new kinds of bacteria developing within the manure pits, changes to the composition of hog excrement, or even a combination of other factors. Others think the foam may be the result of the increased use of distiller’s grain, a byproduct of alcohol and ethanol production that is mixed with hog feed. The use of this additive in hog feed has increased by up to four times since 2001. Unfortunately it seems that no one can find a pattern that can identify any particular cause at this time. In the meantime, farmers have been advised to be extremely cautious while working on hog farms.