For months, residents near the Central Bi-Products rendering facility noticed it. A sharp, rotten-egg odor that lingered and kept coming back. When the Minnesota Pollution Control Agency finished its investigation, the source wasn't hard to identify. The facility had exceeded its hydrogen sulfide emissions limits more than 900 times over roughly a year, failed to properly maintain its wastewater treatment systems, and submitted inaccurate permit reports suggesting everything was under control when it clearly was not.
The fine: $3 million. The required remediation investment: $4.4 million. And the community of Long Prairie will receive $1.2 million of that penalty directly.
In 2020, Farmers Union Industries LLC, the parent company of Central Bi-Products, agreed to pay $130,000 for wastewater overflow and permit violations at its Central Bi-Products rendering plants in both Redwood Falls and Long Prairie. A wastewater pond at the Redwood Falls facility overflowed in March 2019, releasing between 112,000 and 336,000 gallons, some of which reached wetlands in the Minnesota River floodplain, and the MPCA had previously informed the Redwood Falls facility about pond level requirements before that violation occurred.
The 2020 penalty was a fraction of what the company is paying now. When the MPCA calculates fines, it considers not just the severity of violations but whether the company has been here before. Central Bi-Products had been.
The MPCA found that Central Bi-Products violated a hydrogen sulfide limit of .03 parts per million 485 times. That threshold was only permitted to be exceeded twice within any five consecutive days. The facility also surpassed a stricter .05 ppm limit 427 times, despite being permitted to exceed it no more than twice per year. Combined, that's more than 900 permit breaches over a period running from fall 2023 through 2024.
The root cause traces back to wastewater pretreatment. The facility failed to properly operate and maintain those systems, which then overloaded the pond treatment system and generated hydrogen sulfide levels far beyond what the permit allowed. Hydrogen sulfide forms naturally when wastewater isn't properly treated, and the odor it produces is distinctive enough that it rarely goes unnoticed in a community.
On the health side, the MPCA notes that effects are generally tied to exposures significantly higher than typical background concentrations, but even at elevated levels, residents near the facility can experience eye, nose, and throat irritation, headaches, and breathing difficulties, particularly for people with asthma.
The facility also has a separate problem layered on top: it submitted inaccurate discharge monitoring reports from September through December 2023, indicating no issues with floating materials inside its pond treatment system when significant issues existed. Inaccurate permit reporting adds legal exposure beyond the underlying violations, and regulators treat it accordingly.
Beyond the $3 million fine, the company has agreed to spend at least $4.4 million on a supplemental environmental project to overhaul its wastewater pretreatment systems and control hydrogen sulfide going forward. The remediation requirements attached to the settlement are detailed and ongoing.
Central Bi-Products must conduct air monitoring from April 1 through October 31, hold public meetings on its environmental compliance and operational changes, and create a publicly accessible webpage publishing monthly hydrogen sulfide emissions summaries. If levels exceed permit standards again, the company must submit a corrective action plan to the MPCA directly.
Under 2023 Minnesota legislation, 40% of fines exceeding $250,000 go to the community affected by the pollution. The Todd County Community Health and Human Services Department will receive $1.2 million and will direct those funds toward projects benefiting area residents.
The Long Prairie case is a useful read on how compliance situations escalate when the underlying infrastructure problems aren't addressed. Reporting inconsistencies are increasingly treated as early risk indicators rather than cosmetic issues, and regulators are using reported data as a screening mechanism to identify discrepancies that suggest unresolved compliance risk.
That pattern shows up clearly here. The 2020 fine didn't resolve the underlying wastewater treatment vulnerabilities. The inaccurate 2023 reports didn't protect the company from scrutiny. By the time the MPCA completed its investigation, the violations were numerous enough and the reporting gap significant enough that a $3 million penalty was the outcome rather than another warning.
Regulators are showing less tolerance for unresolved or recurring violations and are moving toward shorter timelines for corrective action once noncompliance is identified. For EHS professionals managing industrial wastewater or air quality permits, the takeaway from Long Prairie is practical: maintenance deferrals and reporting gaps don't stay contained. They compound.
