The explosive phenomenon of “manure foam” continues to baffle scientists, but there are signs of a solution, Mother Jones reported on Wednesday.

The problem began to attract notice in 2009, when six industrial-scale hog farms reported suffering blasts caused by gaseous build-up in the underlying pits used to capture the hogs’ excrement. The University of Minnesota reported in 2012 that one explosion killed 1,500 pigs and severely burned a farm employee.

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Minnesota professor Larry Jacobson told the magazine that the foam was also connected to a fire at an empty hog facility in May 2013. Around 25 percent of hog farms in Illinois, Iowa and Minnesota, he said, have confirmed having the dangerous goop.

“The number may be higher, because some operators might not know that they have it,” Jacobson said.

While no direct cause for foam buildup has been identified, Jacobson theorized that one factor was an increase undigested fiber and volatile fatty acids in manure pits, prompted by increased feedings of mush leftovers from corn ethanol processing.

But, he also said that some farmers are having luck using a common cow antibiotic, monensin, to alter the mix in the manure pit and defuse the problem.

In 2009, a university researcher, David Schmidt, released an extended presentation detailing the foam manure problem, which can be seen below.