Neighbors describe the odorscoming from Smith Foundry and Bituminous Roadways as chemical, sickly sweet, metallic and, at times, like burning tires.

People who live near the south Minneapolis iron foundry and asphalt plant have spent years sounding alarms about what the sites are sending into the air — out of concern for their health, but also the simple nuisance of a pervasive stench.

But the state of Minnesota has been out of the business of policing bad smells for three decades. It hands off any complaints to local governments. Minneapolis sends out inspectors but has only documented a single violation.

Rob Czernik, who lives a few blocks away from the two businesses, was one of many people who had repeatedly reported the smells to Minneapolis' 311 line.

"I stopped calling 311 a couple of years ago, because it didn't go anywhere," he said.

Revelations this fall that the Smith Foundry may have violated air pollution rules for years have led to angry community meetings at which the Minnesota Pollution Control Agency's (MPCA) enforcement practices have come under criticism.

The agency has promised to do better, and because of a new law, it will have to face the odor problem directly.

The MPCA was responsible for odor control until 1996. That year, the agency rewrote its rules to change a standard that it said was technologically outdated, and instead advocated for a new regulation that would have the state and local governments collaborate on odor complaints, according to a document laying out MPCA's reasoning for the change.

The new rules were never put on the books, in part because an administrative law judge recommended against them. The judge wrote that business groups and local governments were staunchly against it.

Despite that, odor enforcement in Minnesota largely has been left to local governments for the past 27 years, if they pass their own ordinances against noxious smells, as Minneapolis has.

Chuck McGinley, who has spent his career consulting with regulators, businesses and others on controlling bad smells, said that change ushered in a bonanza for lawyers and advisers like him but didn't solve the problem.

A new law prompted by other malodorous businesses in the metro will put the MPCA back in the odor investigation field. Kari Palmer, air assessment section manager at MPCA, said the agency is in the process of writing up new rules now, and that it would take three years to complete.

Neighborhood complaints

Controlling objectionable odors is a requirement in the 1992 air pollution permit that Smith Foundry still is operating under. But MPCA had essentially abandoned its odor enforcement that year. The agency argued later that the testing method it used wasn't reliable, and that the rule used "numerical standards which bear no relationship to a person's experience of objectionable odors," according to an administrative law judge ruling.

The foundry, which has made iron castings at 1855 E. 28th St. for a century, was accused of violating the Clean Air Act after a surprise EPA inspection this spring. The agency claims Smith was emitting double the amount of fine particulate matter, or lung-damaging soot, that it was allowed to for the past five years. MPCA has disputed some of EPA's claims that Smith is breaking pollution rules.

Next door is Bituminous Roadways, the asphalt plant which also was inspected by EPA but has not been accused of violating the law.

Most complaints about Smith have been smell-related. Ten of the 13 complaints logged with the MPCA from 2018 until early October were about bad odors.

The city's 311 line has received 51 complaints about bad smells from Smith since 2017, said Kelly Muellman, the manager of environmental programs for Minneapolis. Over the same period, there were 28 complaints about odors from Bituminous.

"We do want community members to continue calling us and letting us know about these complaints," she said.

Finding the source

It's not uncommon for it to take decades to address problems with a smelly business, said McGinley, who also is the inventor of the Nasal Ranger, a tool that odor investigators often use.

Minneapolis uses the tool to see if an objectionable odor is still present when an air sample is diluted seven times. Inspectors will take two samples at a site, and if the smell is present in both, then the business is in violation of the city's rules. Bituminous had received one violation since 2017, and Smith has not, though a single sample taken there was in violation, Muellman said.

Residents have long complained that inspectors don't arrive when the smells are the worst. It's a well-known issue of enforcement.

"You may get 10 calls of an odor nuisance," said McGinley, who worked briefly at the beginning of his career as an odor investigator for MPCA. "And if you're lucky, one out of the 10, you'll get there, and there will still be a smell," he said.

Picking apart the responsibility of the two businesses has also been a challenge.

Adolfo Quiroga, the president of Smith Foundry, said in an interview that the asphalt plant is likely responsible when residents complain the air smells like burning tires.

But former MPCA research scientist Greg Pratt, who often rides his bike along the Midtown Greenway next to the foundry, said he also has detected smells coming from that facility.

"There's a kind of a metallic odor [and] taste to the emissions when you inhale them," he said.

Smells are only one of the concerns residents have raised about Smith. Most are worried about hazardous air pollution, and want the facility shut down entirely. Testing of the business's smokestacks was conducted this week, and MPCA has promised to release the results publicly and update the foundry's permit by the end of next year.

Bituminous, the asphalt mixer, already has committed to leaving its location by the end of 2025. It is closed for the winter, but earlier this fall, Todd Smedshammer, a production manager there, told the Star Tribune that the business had put additives into its mixing process to reduce the smell.

"Reality is... we've done what we can," Smedshammer said.

Improving investigation

At the behest of lawmakers, MPCA will now take public comment and write up the rules for the new state odor regulations. The law covers only the seven-county metro area, and several types of businesses are exempted, including sewage plants, restaurants and refineries.

Inspectors would investigate a potential odor source within 48 hours if it receives at least 10 complaints.

MPCA has a standard on the books already that addresses some smells — a limit on hydrogen sulfide, the chemical responsible for a rotten-egg stench.

"A lot of times that hasn't necessarily helped communities because we can't always identify what that pollutant is," said Palmer, of the MPCA.

The agency is talking to other states now about how they handle odor issues, Palmer said. McGinley said inspectors should behave like detectives putting together the pieces of a crime. Patterns in smell reports might show the need to visit a facility at certain times of day, for example.

He said the new law has some weaknesses — like only covering the metro area and requiring 10 complaints before regulators take action. But it's a "good start," McGinley said.