Locals used to call it the smell of money. The South St. Paul stockyards and the strong animal odor that accompanied them were defining elements of this blue-collar community.

The last of the stockyards closed in 2008, and many assumed the smell would leave with it. But this past spring and summer, residents complained of a pungent odor wafting into neighborhoods as many as five nights a week.

A handful of South St. Paul businesses that process animal products were suspected of causing the stink. Initially, there was finger-pointing amongst the businesses, city staff said. Now, four have joined forces to root out the problem, they've told the city.

The businesses call themselves the "odor consortium." With a nod from the city, they have agreed to investigate complaints and take odor measurements for a year's time. The group has set up a phone hotline and website so residents can lodge complaints.

The businesses are using an outside environmental consulting firm and have agreed to share their data with the city.

"Track back the history of this community and smell has always been associated with it," said South St. Paul City Administrator Steve King. "People assumed it was from having stockyards here. With the disappearance of that industry, there was a tacit assumption when those facilities were gone, the smell would disappear. And it hasn't."

The consortium businesses are ground beef producer Dakota Premium Foods, Twin City Hide, Twin City Tanning and Sanimax, a rendering company. The four businesses and their attorney could not be reached for comment.

They city has registered 62 smell complaints in 2012, well above the handful they usually receive, said city planner Peter Hellegers. There were a higher concentration of complaints from southside residents, but they came in from all over the city.

"Something was different this past year," said Hellegers, noting that the smell at times engulfed City Hall. "This past year was terrible, particularly during the warmer months. July and August were pretty bad."

The smell was so foul at times that resident Tom Carstenbrock cancelled barbecues and other outdoor events.

"The smell was kind of like a dead carcass smell. ... It was embarrassing for family and friends to come over," said Carstenbrock, who lives near Harmon Park, south of Interstate 494 and just west of Concord Street. He's within 2 miles of all four consortium businesses.

Carstenbrock and his wife, who have lived in their South St. Paul home for three decades, said they've encountered smells wafting through the neighborhood in years past, but never for that duration. He estimates it stunk three to five days a week throughout the spring and summer.

"We've been here a long time. For some of the young neighbors on our block, they were just appalled by it. It was really rough on them and the kids. The kids really had a hard time," Carstenbrock said.

After neighbors complained to the City Council last summer, the smell stopped. He suspects the businesses got the message.

"These are tax-paying businesses. We are taxpayers, too. It's the duty of the council to ensure the right thing is done," Carstenbrock said.

"I am really depending on the city to validate the testing and ensure the quality of the air is appropriate."

South St. Paul Mayor Beth Baumann said she is hopeful the data provide answers and the culpable parties can clear the air.

"I hope what comes out of it is a clear indication of where the odor issue is stemming from. What businesses are creating these problems? What can they do to mediate them?" Baumann said. "Let's work together to try and figure this out."

The mayor praised the businesses for taking the initiative.

"I really appreciate the businesses stepping up. This indicates they get it. They understand. They want to work with us to resolve the odors so we can bring more business in," Baumann said. "What we are hearing from people is they are not moving in down there because it stinks. That is something we have to figure out how to control."

This isn't the first time city leaders have tried to sniff out the odor problem. A city land-use study done for properties around the river identified unpleasant smells as a barrier for future redevelopment.

"It was a nonstarter for future development," Hellegers said.

There was even talk of enacting an odor ordinance around 2010, but odor is much harder to quantify than sound or light. The city hired an expert who used a field device called a Nasal Ranger. It looks like a megaphone held up to the nose. The city dropped the ordinance idea.

"In the end, it didn't have enough push behind it to go forward," Hellegers said. "It just sat there on the shelf."

Today, a general city nuisance statute covers any noticeable smell beyond property lines. Businesses could be issued a $200 administrative citation. Hellegers said he doesn't believe a business has been cited for a smell violation.

"If we need to cite somebody, it's always an option on the table," Hellegers said.

King, the city administrator, said the city is trying to solve the issue without alienating businesses.

According to city records, 200 people work at Twin City Hide and Twin City Tanning, which operates connected facilities. Nearly 300 people work at Dakota Premium. Hellegers said he didn't know the number of Sanimax employees but estimates it's in the hundreds.

"They are the legacy," King said. "The council is not in any kind of attitude to go in and act like the bully. The businesses we are talking about here have long-term presences here."

Shannon Prather is a Twin Cities freelance writer.