Maine fire could be latest in pig barn explosion epidemic
28 May 2013
An explosion and fire at Newburgh in Maine on May 24 killed at least 30 pigs but did not cause any human fatalities. The farm owner was able to save some of his livestock, and told local media that heaters in the barn might bear some responsibility for the blast.
Explosions in North American pig barns have reached epidemic proportions over the last ten years, thought to be partially due to the increase in the proportion of barns built over manure pits, which release methane that explodes when it comes into contact with an ignition source in the shed.
One huge fire destroyed a pig farm in Iowa killing 1,500 animals. An investigation found methane gas was found to be the most likely cause, released from the year’s worth of manure beneath the barn.
Other pig barn fires have contained a new element – a perfect circle of dead pigs. The cause here has been traced to hydrogen sulphide, another deadly gas emitted from pig manure. The gas kills through respiratory paralysis and is also highly corrosive, eating away at the barn’s electrical circuits, creating many potential ignition sources for methane.
Farmers have also reported an increased incidence of a strange foam that appears in manure pits prior to the fires. This foam consists of 60% methane and is consequently highly flammable.
In the past five years, University of Minnesota researchers have looked at up to 40 manure foam fires and blasts which have killed thousands of pigs and cost farmers millions of dollars. Initial research shows that the foam could be related to the animals' diet.
One of the "Pig Bang" theories is that the foam is linked to the increasingly popular practice among US hog farmers of mixing swine feed with dried distillers’ grains, a byproduct of corn processing for ethanol, to cut down on feed costs. Researchers say distillers grains contain high levels of fatty acids that pass through the pigs' digestive system and help form bubbles in the manure that causes the foam.