According to The Minnesota Daily, hog farmers across the Midwestern United States are beginning to discover methane-packed foam on manure holding pits which, when exposed to a spark, becomes dangerously explosive.
In September of last year, one such explosion in Iowa took the lives of 1,500 pigs while also injuring one worker. The year prior, a farmer found some of the foam and tried removing it, resulting in a blast that knocked him back roughly 30-40 ft from the site.
A team from the University of Minnesota has been investigating the foam since reports became widespread. They found that the foam - which they believe consists mostly of bacteria - develops in manure pits. Still, while they're not entirely sure how to stop it from spreading, they have noticed a correlation between dried distillers grain (created through ethanol production) insoluble being added to the hogs' diets and the foam.
According to a 2009 article posted on the Iowa State University website titled, "Livestock Producers Facing Explosion Hazards with Manure Pumping", "[liquid] manure in pits undergoes slow decomposition which creates several gases including methane and hydrogen sulfide, both of which are flammable."
If the barbaric, emotionless treatment of sentient animals, gallons of antibiotics utilized in production, environmental impact, or rampant spread of disease have all failed as incentives to avoid industrial pig farming, perhaps exploding fecal foam might do the trick.
Photo credit:cc:flickr.com/photos/jennifrog/90816492 and TDIV