According to the University of Minnesota Extension Service, foaming in swine manure pits “has become a serious safety concern” in the last few years. Foaming fills pits, reducing manure capacity but also trapping explosive methane gases. Farmers are urged to turn off pilot lights and maintain full ventilation during pumping. Fans should run even when pigs are removed.
Despite the thousands of pig barns with manure pits in the American Midwest, there have been only six reported explosions since the foam began appearing in 2009. But, though it doesn’t happen often, when it does it is a disaster.