The Nebraska AltEn ethanol plant lawsuit is a civil environmental case filed by then-Attorney General Doug Peterson on March 1, 2021, in Saunders County District Court against AltEn, LLC, the operator of an ethanol plant near Mead that used pesticide-coated seed corn as feedstock and left behind tens of thousands of tons of contaminated byproducts. The case has been stayed since April 2024 for confidential settlement negotiations aimed at a global resolution, and as of December 2025 it has not gone to trial or produced a final consent decree. In the meantime, a coalition of seed companies has been funding and carrying out the cleanup under Nebraska’s Voluntary Cleanup Program.
Why the State Sued
AltEn operated a 25-million-gallon-per-year ethanol plant near Mead from roughly 2013 to early 2021. The facility was originally permitted to use field corn, but under ownership that took over in early 2015 it switched to processing discarded seed corn treated with neonicotinoid insecticides and fungicides. That change concentrated pesticides into two byproducts: a solid residue called wet cake and process wastewater.
For years, AltEn sold the wet cake to farmers as a soil conditioner. The Nebraska Department of Agriculture ended that in 2019 after finding pesticide levels too high for safe land application or livestock feed. With no approved outlet, AltEn stockpiled more than 84,000 tons of contaminated wet cake on its property. The plant also maintained three wastewater lagoons that regulators said were overloaded, with damaged liners and breached berms.
State regulators had been documenting problems well before the lawsuit. The Nebraska Department of Environment and Energy (NDEE) issued a notice of violation in July 2018 covering stormwater management and sediment control failures. A consent order in April 2019 set deadlines for lagoon repairs, groundwater monitoring, and other corrective actions, but the state later alleged AltEn missed them.
Matters came to a head in February 2021. NDEE issued an emergency order on February 4 requiring AltEn to cease operations, and the plant shut down by February 10. Two days later, a frozen pipe burst and released roughly four million gallons of pesticide-laced wastewater from a digester tank into a drainage ditch and onto neighboring properties, reaching waterways more than four miles downstream. NDEE issued a second emergency order on February 20 requiring cleanup of the spill. According to the state’s later complaint, AltEn refused to address it.
What the Complaint Alleged
Peterson’s 97-page complaint named AltEn, LLC as the sole defendant and alleged 18 causes of action, including violations of the Nebraska Environmental Protection Act, the Integrated Solid Waste Management Act, multiple permit conditions, and the 2019 consent order.
The specific allegations grouped into three categories:
- Solid waste violations for operating an unpermitted solid waste facility by storing thousands of tons of pesticide-contaminated distillers grain on site, and for disposing of solid waste at unpermitted locations.
- Water permit violations for failing to maintain stormwater pollution prevention plans, failing to use best management practices, and allowing unauthorized discharges from breached berms and improperly maintained lagoon liners.
- Consent order violations for failing to complete lagoon repairs, implement a groundwater monitoring plan, and meet reporting deadlines.
The state asked the court for three things: an order requiring AltEn to properly dispose of its contaminated byproducts, mandatory compliance with state environmental statutes and NDEE orders, and civil penalties. Under the Nebraska Environmental Protection Act, each violation can carry fines of up to $10,000 per day at the court’s discretion. The complaint alleged AltEn had been in violation since at least June 2019, creating substantial penalty exposure.
The Parallel Seed Company Lawsuits
In February 2022, six seed corn companies filed two separate federal lawsuits in U.S. District Court in Omaha against AltEn, its president Tanner Shaw, and manager Scott Tingelhoff. One suit was led by Pioneer Hi-Bred International and joined by Corteva Agriscience, AgReliant Genetics, Beck’s Superior Hybrids, and Winfield Solutions; the other was brought by Syngenta. Unlike the state’s case, the federal suits named Shaw personally and alleged that AltEn principals had abandoned the Mead site and sold off company assets to shield funds from creditors. The Pioneer-led suit characterized those asset transfers as fraudulent and sought to claw them back.
Those federal lawsuits settled in November 2025, though the terms have not been publicly detailed. The settlement is relevant to the state case because the Saunders County stay was granted to let the parties pursue a global resolution covering all outstanding litigation tied to the AltEn property.
Who Is Paying for the Cleanup
With AltEn’s operators out of the picture, six seed companies — Bayer, Syngenta, Corteva, AgReliant, Beck’s Superior Hybrids, and Winfield Solutions — formed the AltEn Facility Response Group in 2021 and applied to the NDEE’s Voluntary Cleanup Program. By August 2023, the group had spent more than $28 million on remediation.
The most visible milestone came in September 2025, when the final load of stabilized wet cake was trucked off the property. More than 160,000 tons of the material were removed and disposed of at a permitted off-site landfill. The lagoons are a harder problem. In May 2026, the Nebraska Department of Water, Energy, and Environment (DWEE, formerly NDEE) approved a remedial action plan for roughly 118,000 tons of pesticide-polluted lagoon solids. The plan calls for solidifying the material with soil and Portland cement, consolidating it within two of the three lagoons, capping it with a synthetic liner, and installing a passive gas venting system. An environmental covenant would permanently restrict future use of the land, prohibiting homes, schools, or childcare facilities and barring disturbance of the capped areas.
Soil and groundwater work continues under an amended agreement from September 2024. A remedial action plan for on-site soils is due by August 2026, and one for groundwater by December 2026. DWEE is also reviewing a construction permit for an EcoVap Tower to evaporate stormwater collected at the site and is conducting an off-site assessment of potential pesticide contamination in nearby farm fields. A University of Nebraska research team estimated that long-term environmental and health monitoring could cost up to $1 million per year over the next decade.
Where the State Case Stands
Judge Christina Marroquin of the Saunders County District Court granted a stay in April 2024 so the parties could pursue confidential settlement discussions aimed at a global resolution of all AltEn-related litigation. The case remains paused for those negotiations as of December 2025. Court filings suggest any eventual agreement would likely include permanent environmental restrictions on the land and groundwater and provisions allowing the state continued access for contamination monitoring. Peterson, who served as attorney general from 2015 to 2023, is no longer in office; his successor, Mike Hilgers, now oversees the matter.
The federal designation question has been answered separately. An EPA Region 7 enforcement director told state lawmakers that Superfund designation was unlikely because the pesticides found at the plant are not classified as hazardous under CERCLA, which limits federal authority. As long as the voluntary cleanup kept making progress, the EPA said it was comfortable deferring to state regulators.
The Law Nebraska Passed in Response
While the lawsuit was being prepared, the Nebraska Legislature moved to prevent a repeat. Senator Bruce Bostelman introduced LB 507, which prohibits the use of pesticide-treated seed corn in ethanol production if the resulting byproducts are unsafe for livestock consumption or land application. The bill passed 43–0 and was signed into law with emergency status by the governor on May 5, 2021, taking effect immediately.