The Science of Hog Farm Odors

Hog-farm odors are a bit like good art: You know it when you smell it. But in the North Carolina hog-farming lawsuit, an expert witness attempts to quantify smell with more scientific methods.  When expert witness Shane Rogers steps into a witness box in federal court these days, he takes pains to explain why he thinks some hog farms in eastern North Carolina create nuisance-level odors. First, the Clarkson University environmental scientist lays out his approach to feces forensics. He hunts for a very specific bacterium called Pig2Bac, a microbe native to the gut of swine that gets excreted with hog feces. “If you have found Pig2Bac you have found pig feces,” Rogers this month told 12 jurors hearing the second of 26 hog farm nuisance lawsuits filed against Smithfield Foods, the largest pork producer in the world. Allies to Smithfield, meanwhile, are working hard to counter Rogers’ narrative. In court filings and elsewhere, those allies reject the argument that a bacterium from hog guts is a good proxy for unreasonable farm odors.“Never in the history of the world has anyone used this as a proxy for odor,” said attorney Mark Anderson of McGuireWoods, the law firm representing Smithfield.