Website Wired.com reported that the six farms were blown up after methane trapped in an unidentified, pit-topping foam caught a spark. In the afflicted region, the foam is found in roughly one in four swine farms. Charles Clanton, University of Minnesota, said, “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. Whatever has happened is new.” Among potential causes of the foam are new bacterial communities that cause foam to form, or a change to the molecular structure of hog waste – a new foodstock, for example, or a pit-cleaning soap that makes the waste frothier. It could also be caused by a combination of the two – or neither of them. Distillers Dried Grains and Solubles (DDGS) have also been suggested as possible cause. Scientists have so far been stumped by the foam’s patterns. Once the foam’s established, it keeps coming back, regardless of efforts at cleaning and decontamination.