Hog farmers across the US are dealing with a pretty shitty problem. A mysterious fecal foam has begun bubbling up from beneath barn floors, down in the darkness where pig manure falls, burping dangerous quantities of methane and hydrogen sulfide. Sometimes, though, it ignites, blowing up not just the barn but all of the pigs inside.
But this isn't something out of Monty Python. Obviously, exploding barns full of pigs and their mysterious fecal foam is an expensive problem, so farmers are eager to figure out what's going on. Science writer Sarah Zhang just published a sleuthing report on what's causing the poop to foam in the first place, and she traces the problem back to a byproduct of ethanol production, something that U.S. farmers started feeding their pigs around the same time the foaming started. Of course, the government heavily subsidises ethanol production, making this potentially dangerous food source very cheap. But does this mean a federal program is making pig shit explode, costing farmers millions?