Hog farming is even grosser than you imagined. Farms keep spontaneously blowing up due to chemical interactions involving bacteria-laden gas and a brown goop of sketchy origin. Ars Technica writes:
Since 2009, six farms have blown up after methane trapped in an unidentified, pit-topping foam caught a spark. In the afflicted region, the foam is found in roughly 1 in 4 hog farms.
There’s nothing farmers can do except be very careful. Researchers aren’t even sure what the foam is. “This has all started in the last four or five years here. We don’t have any idea where it came from or how it got started,” said agricultural engineer Charles Clanton. “Whatever has happened is new.”
A gelatinous goop that resembles melted brown Nerf, the foam captures gases emitted by bacteria living in manure, which on industrial farms gathers in pits beneath barns that may contain several thousand animals. The pits are emptied each fall, after which waste builds up again, turning them into something like giant stomachs: dark, oxygen-starved percolators in which bacteria and single-celled organisms metabolize the muck.