Some research suggests that the plethora of chemicals and pathogens found in liquid manure can have serious health impacts, ranging from respiratory disease to potentially lethal antibiotic resistant infections. Opponents fear wider use of manure irrigation will increase the risk of human illness and drinking water contamination.

Critics also question the ability of the DNR, relying mostly on citizen complaints and self-reporting by the huge dairies, to adequately regulate a practice that has already been shown to pollute waters and to drive people from their homes.

Such concerns have prompted officials in Wisconsin’s Adams County to pass a moratorium against the practice.

It is also an issue elsewhere in the country.

In Minnesota, according to the Wisconsin DNR, 10 counties prohibit manure irrigation.

In North Carolina, 95 percent of the swine farms use manure irrigation. Fish kills and pollution prompted state officials to ban the practice on new or expanding mega-farms, and farms now must follow much more restrictive regulations. In Michigan, a company shut down its mega-farms after violations and lawsuits related to the flawed use of manure irrigation.