The Waterkeeper Alliance and North Carolina Riverkeepers are calling on Gov. Pat McCrory (R) to declare a state of emergency over a viral outbreak that's killing hogs en masse in North Carolina.

With its spread aided by the unusually cold winter, porcine epidemic diarrhea or PED has reportedly struck nearly a third of North Carolina's 3,000 major hog farms. North Carolina is the second-biggest hog producing state after Iowa.

The environmental groups are concerned about how all those hog carcasses are being disposed of. They wrote a letter asking N.C. Agriculture Commissioner Steve Troxler (R) to take immediate action necessary to protect human health and the environment. They also urged him to request that McCrory declare a state of emergency over the mass hog deaths. That would allow state and local authorities, including county health directors, to inspect hog farms and implement emergency plans and requirements for handling dead animals.

The usual practice for handling dead hogs is to bury them in mass graves. The Waterkeepers are concerned that in North Carolina's coastal plain, where most hog farms are located, the practice presents a high risk of contaminating shallow groundwater and nearby streams, allowing pathogens to enter drinking water and recreational waters. They are also concerned about dead hogs being left piled up for days in "dead boxes," with blood and other liquid from them seeping into groundwater and running into streams. In addition, buzzards and insects feed on the discarded hog carcasses, and can spread the virus to other farms.

"While we understand that PED cannot be directly transmitted to humans, the massive numbers of pigs that have died from this virus pose a significant concern to the public health if not disposed of properly," said Gray Jernigan, a North Carolina-based attorney for Waterkeeper Alliance. "There is currently little to no government oversight of carcass disposal in the midst of this epidemic, and we are calling on the State to take action as authorized by law to protect the citizens of North Carolina."

The groups also submitted a Freedom of Information request to Troxler to get more information about the full scope of the PED outbreak and the state's response. And they have started a petition calling on McCrory to take action.

The following video by the Waterkeeper Alliance show the effect the PED virus is having on North Carolina farms and the problematic ways in which dead animals are being disposed of by some operations: