(Adds details about pits holding hog waste, background)
CHICAGO, Oct 13 (Reuters) - Smithfield Foods said it resumed partial operations on Thursday at the world's largest hog processing facility in North Carolina, after shutting it due to Hurricane Matthew.
The company also said it had a report of flood waters rising into a pit holding hog waste at one of the farms contracted to sell it livestock. It has not received reports "to date" that any of the in-ground pits have fallen apart due to flooding from the storm, according to a statement.
Farmers and food companies in North Carolina are working to assess damage from Matthew, the most powerful Atlantic storm since 2007, and get back to work as parts of the state remain under water.
Environmental regulators and activists have been concerned about flood waters inundating pits holding hog waste after Hurricane Floyd overwhelmed them in 1999. The waste, mixing with water, can make its way into rivers, streams and the Atlantic Ocean.
On Wednesday, North Carolina's Department of Environmental Quality said that some pits holding hog waste had been inundated but posed a minimal threat to the environment.
Smithfield employees are working "around the clock to determine the impact of the extraordinarily high levels of rain in North Carolina on the company's farms and processing facilities," the company said.
They are monitoring reports on pits from on the ground and air, it said.
Smithfield's Tar Heel, North Carolina, hog plant, the biggest in the world, had been closed since Saturday as Matthew made it difficult for people to get to work and for producers to deliver livestock. It has an estimated daily slaughter capacity of 32,500 hogs.
The company's plant in Clinton, North Carolina, also was operating at a reduced rate on Thursday, according to the statement. A plant in Gwaltney, Virginia, was back to full capacity.
Both facilities were recently idled by the storm. They have a daily estimated slaughter capacity of roughly 10,000 head, according to National Hog Farmer magazine.
"None of our processing plants in North Carolina or Virginia suffered substantive damage, but flooding is making the movement of hogs and employees difficult," Smithfield said.
(Reporting By Theopolis Waters, Jim Brumm and Tom Polansek; editing by Chizu Nomiyama, Bernard Orr)