Pam Seebach, a pastor of Newburg United Methodist Church, read a statement from the Fillmore County Amish community opposing the 5,000-head sow farm being proposed near Newburg Township.

A group of southeastern Minnesota residents are urging state regulators to put extra scrutiny on a proposed Fillmore County sow farm, saying the region's fragile geology could make a manure spill catastrophic.

The Minnesota Pollution Control Agency is considering permits for Catalpa LLC, which wants to build a 5,000-head sow farm near Newburg Township and apply manure on area cropland.

The Land Stewardship Project and Responsible Agriculture in Karst Country are asking the agency to require Catalpa to complete an Environmental Impact Statement (EIS), a level of review unheard of in Minnesota for a livestock operation.

The MPCA doesn't comment on pending permits but extended the public comment period on the proposal until Tuesday because of the high level of public interest. A decision is expected later this summer.

More than 40 people gathered outside the Minnesota Pollution Control Agency on the last day of the comment period. They wore bright yellow T-shirts and chanted, "Say yes, EIS!" Afterward, they met with MPCA staff and had a meeting scheduled later with Gov. Mark Dayton.

"I am absolutely not against animal agriculture. It's historically been in our area," said Mark Spande, who grew up in Fillmore County and grows corn and soybeans on the farm that's been in his family for over 100 years. He has raised cattle in the past.

Members of the Land Stewardship Project and Responsible Agriculture in Karst Country held signs during a news conference outside of the Minnesota Pollution Control Agency on Tuesday, July 3, 2018, in St. Paul, Minn.

"It's just the magnitude of this," he said of the proposed sow farm. "We didn't build our house there in expectation of something like this happening."

Sinkholes and disappearing springs are common in southeastern Minnesota, where porous limestone allows surface water to enter groundwater quickly.

Residents are concerned about manure leaking into groundwater, which people rely on for their drinking water. Several of those opposed to the farm have private wells, some of which already have high nitrate levels from farm runoff. People are also concerned about air quality.

"The potential environmental impacts of this proposed hog factory are enormous," said Pam Seebach, pastor of Newburg United Methodist Church.

The farm would be managed by Iowa-based Waukon Feed Ranch. President Brad Herman says his company is working with a local landowner and that the sow farm will meet all Minnesota regulations.

"If you look at our permit, all the documentation is there, and the air modeling is more than what would be necessary," Herman said, adding that the owners anticipated some neighbors might oppose the project.

But Herman said a public meeting in Mabel last month attended by several hundred people took him by surprise.

"It turned out to be just a venting point," he said, adding that the short PowerPoint presentation he had prepared and the consultants who were there to answer questions about the project were silenced by project opponents.

Herman said producing pork "is a growth industry," with strong demand in the U.S. and internationally. At the same time, farmers in the Midwest are looking for ways to make more money because of low corn and soybean prices.

He said he's hopeful the MPCA will give the project a green light. The project also needs a permit from Fillmore County.

"Hopefully the comments will be such that any issues that would come up can be addressed," Herman said. "We want to do what's right and follow the rules."