Nebraska and EPA Look for Solution

Seed Companies Step Into Ethanol Plant Contamination Caused by Treated Corn Seeds

One of the piles of contaminated distillers grains or wet cake from seeds treated with pesticides at the AltEn ethanol plant and Mead Cattle Co. just outside of Mead, Nebraska. (DTN image by Chris Clayton and Nick Scalise)

Editor's Note: This story has been updated. The original appeared April 30.


OMAHA (DTN) -- Agricultural corn seed giants started working on a containment strategy as Nebraska environmental regulators began taking stock of the pesticide and fungicide contamination at an ethanol plant that processed treated seeds almost exclusively. Seed companies involved have declined to be interviewed about the situation at the Mead, Nebraska, ethanol plant.

Seed companies stepped in and hired a company to take over environmental cleanup at the AltEn LLC ethanol plant, capable of producing 24 million gallons per year, outside Mead, about 20 minutes from the suburbs of Omaha.

AltEn shut down its plant in early February after the Nebraska Department of Environment and Energy (NDEE) issued an emergency order to cease operations at the plant on Feb. 4 following numerous environmental violations. AltEn completed shutdown on Feb. 8.

However, cold weather several days later led a pipe to burst at the plant, causing 4 million gallons of pesticide-filled water to flow downstream.

Records provided to DTN also show state regulators began to query seed companies such as Bayer and Syngenta about the regulations for disposing treated seed, including questions about how to clean up millions of gallons of water in lagoons contaminated with pesticides, and whether millions of pounds of discarded treated seeds should be composted.

Nebraska's attorney general filed a lawsuit in early March to officially shut down the plant. The environmental situation created at AltEn reached a level that Nebraska's unicameral Legislature voted unanimously 48-0 on Thursday for final passage on a bill that would ban ethanol companies from using treated corn seeds in the state. The bill goes to Gov. Pete Ricketts. If signed into law, Nebraska would be the first state to officially ban ethanol plants from processing treated seed.

AltEn is one of just two known ethanol plants in the country that accepted treated seed. The second, in Kansas, is licensed for only 2 million gallons of production and processes significantly smaller volumes of treated seed.

In its efforts to advertise its services as a location to dispose of treated seed, AltEn sent out emails last year stating that it was under "long-term contract" to accept discards from many major seed companies, including Monsanto (now owned by Bayer), Syngenta, Dow (now owned by Corteva), AgReliant and Land O'Lakes, through its Winfield United business. AltEn advertised it accepted the treated seed at no charge.

AltEn advertised that it was still accepting the treated seed even after state officials had banned AltEn from allowing the leftover wet cake to be used as an area soil conditioner.

DTN has requested interviews with many of the seed companies involved to discuss the situation at Mead and how it will change how discarded treated seed will be disposed of in the future. Those companies have either declined to be interviewed or have not responded to requests.

Management and ownership for AltEn also have not responded to repeated requests for interview by DTN.


Without specifying the potential contamination risks, NDEE on April 29 issued a statement that the department is now working "with the support of the Environmental Protection Agency" to address the environmental issues at AltEn.

"NDEE and EPA are exploring all available options for addressing the environmental issues at the site," NDEE stated.

Jim Macy, director of NDEE, also credited "seed industry representatives" who are now working at AltEn voluntarily to deal with emergency measures to reduce the level of wastewater in lagoons and put in some stormwater measures to prevent discharges from the land piles of distillers grains.

The site has tens of millions of gallons of wastewater filled with high levels of neonicotinoid pesticides and fungicides exceeding EPA safety levels. Another 84,000 metric tons of distillers grains (equivalent to about 10 million bushels of treated seed) are piled on the site. State inspectors are testing soils in and around the site for leaching contamination.

While the water and potential ground contamination came from millions of bushels of discarded seed by the major seed companies at the ethanol plant over multiple years, Macy still credited the industry for "proactive" measures to deal with the current contamination.

"These actions are a crucial next step at the facility as more permanent solutions are investigated," Macy said.

Macy's statement noted that EPA is now working with the state and "discussing a long-term commitment by the seed industry to fully address the environmental issues at the site.

The Nebraska Sierra Club on Thursday sent an action alert to its members, calling on them to demand an investigation into the quantities of pesticides and fungicides in the wastewater and piles of wet cake. The Sierra Club described the situation as a "ticking time bomb."

"I really can't wrap my head around the fact that the seed companies were dumping contaminated seed there for years without realizing there were going to be problems," said Al Davis, a former Nebraska state senator who now lobbies for the Sierra Club in the state. "The seed companies have good scientific engineers that are working for them. Did they know what's going on? It's disingenuous to say they are going to come in and solve all of our problems because they're the ones that really caused the problems in the first place."

Corteva, which owns the Pioneer seed corn brand, told DTN in an emailed statement that it was "fully committed to following all laws and guidelines for the safe use and discard of treated seed."


EPA, the agency in charge of registering pesticides, doesn't track pesticides used in seed treatments the way it does other pesticides. That's because seeds coated with pesticides fall under a legal exemption from EPA monitoring for "pesticide-treated articles," along with products like pesticide-treated lumber. As a result, the only federal laws governing treated seeds are found on the seed treatment product labels, which warn users not to use them for feed purposes and instruct them to dispose of treated seed by burying them away from bodies of water.

Because many pesticide-coated seeds qualify as a hazardous waste material, their disposal can fall under various state laws governing hazardous waste management -- as it has in Mead. A few states, such as Vermont and New York, have also created legislation requiring their state pesticide regulatory agencies to monitor and track treated seeds. But, for the most part, seed companies follow their own industry-created and industry-policed guidelines for proper disposal, found here:….


The chemicals coated on the treated seed found at AltEn are mostly insecticides and fungicides. Neonicotinoids are the most numerous insecticides found at the AltEn facility grounds and in ponds and surface water around the facility. This class of insecticides have been widely used by seed companies to protect a range of crop seeds from soil insects for the past decade. The fungicides are mostly from the QoI (strobilurin) and triazole groups, which are also popular choices for coating on seed to protect it from early season soil diseases. Seed treated with these fungicides and insecticides is now ubiquitous in the corn industry, with more than 90% of corn seed treated upstream by companies before it is sold to retailers and farmers, according to a 2019 Kynetec survey.

After the AltEn pipe rupture on Feb. 12, NDEE began collecting more downstream samples. At least one farm pond five miles from the ethanol plant had tests showing neonicotinoid insecticides, which EPA says are a danger to fish and other wildlife.

Although the insecticides and fungicides are applied to the seed in small amounts, EPA and state regulators in Nebraska have found high concentrations of them in the DDGs, wet cake, wastewater and storm runoff from the AltEn facility. Sampling conducted by the state in 2019 through 2021 has revealed concentrations of neonicotinoids in the facility's lagoons and surrounding land that were sometimes tens of thousands of times greater than levels that academic scientists and regulators have found to be safe for humans, animals and insects, including bees.

For example, in his work with colleagues at Purdue University, entomologist Christian Krupke has found that concentrations of the neonicotinoid insecticide clothianidin (sold as Poncho by Bayer) ranging from 2 to 1,200 parts per billion (ppb) would kill 50% of aquatic insects exposed. In pollen and nectar, concentrations as low as 4 ppb over two days can be fatal to adult honeybees, according to EPA.

For humans, EPA's maximum acceptable levels of neonicotinoids in food and water range from 4 to 70 ppb per day.

In the wastewater lagoons of AltEn, regulators found clothianidin at levels ranging from 7,000 ppb up to 112,000 ppb between April and December 2019. Another neonicotinoid, thiamethoxam (sold as Cruiser by Syngenta), was found at levels ranging from 2,400 ppb to 35,400 ppb in that same time period.

"Those levels are extremely high and likely lethal to any insect," Krupke told DTN. Neonicotinoids are extremely water soluble, meaning that they dissolve easily in water and then remain stable in groundwater, able to travel long distances in it. Even if those amounts lessened as water moved away from the facility in rain, leeching and storm runoff, "it would take an awful lot of dilution to get these concentrations to an environmentally benign level," Krupke said.

When EPA sampled soil and surface water 1 mile downstream from AltEn's facility in early March, clothianidin levels were at 540 ppb. When regulators ventured more than 5.6 miles away from the facility and collected surface water, clothianidin levels still came in at 90 ppb.

In a resident's pond located about 7 miles southeast from the Mead facility, near the town of Ashland, state regulators detected clothianidin concentrations at 50.3 ppb and thiamethoxam concentrations at 60.6 ppb on March 26.


While federal and state regulators and residents in and around Mead and Ashland are still working to understand the full extent of human and wildlife exposure to these levels, the pesticide contamination at AltEn appears to have had negative effects on nearby wildlife.

For the past four years, bee researchers have watched their honeybee colonies collapse and die off at the Eastern Nebraska Research and Extension Center (ENREC) in Mead, located about 4 miles from the AltEn facility.

Since 2017, UNL's lab has lost every hive university entomologists have tried to start -- over 36 hives -- affecting the research program by roughly $21,000 for the cost of bees, contaminated equipment, and lost honey revenue, Judy Wu-Smart, a Nebraska Extension entomologist, wrote in a paper she published last August.

The Nebraska researchers' bees have served as the region's canary in the coalmine, Wu-Smart said in her paper. "Bees are biological indicators of the surrounding environment, and unfortunately, pollinator protection policies currently prevents regulatory agencies from investigating these beekills, because the colonies did not die from a misuse of a pesticide application but rather likely from contaminated water and forage (nectar/pollen)," she wrote.

"(T)he inability to keep bees alive around ENREC indicates a greater ... concern highlighting the urgent need to examine potential impacts on local communities and wildlife as well as other research programs at ENREC," she concluded.

By scrutinizing the timing and duration of the die-offs, as well as testing pesticide residue in milkweed at their research facility, the researchers pinpointed AltEn as the source of the contamination, as the cocktails of fungicides and insecticides flowed south through streams, ditches and water channels into and around the beehives.

Water has not been the pesticide contamination's only route of exposure, however. The Nebraska Department of Agriculture has also received reports of geese and other birds, as well as pets, becoming sick and dying after AltEn sold its contaminated wet cake to farmers to apply to their fields as a soil amendment, Wu-Smart said in her paper.

Emails show that as far back as October 2016, Nebraska Extension specialists were raising concerns about AltEn's use of treated seed, but they were told AltEn had the proper air, compost and wastewater permits necessary to operate.


Following a records request, NDEE provided DTN with a series of emails involving Bayer and Syngenta.

Within days of the Feb. 12 pipe burst, NDEE legal counsel met virtually with Bayer officials and an attorney who specializes in superfund negotiations and litigation. Talk revolved around the potentially significant environmental emergency related to the disposal of treated seed and the pipe burst.

Bayer representatives on the call included an attorney involved in health, safety and environment and real estate law; Bayer Crop Science state government affairs lead for the south-central United States based in Texas; and a partner with the law firm Spencer Fane who has represented clients across the country on environmental enforcement cases and site cleanups and worked at EPA for 15 years.

On Feb. 21, Macy forwarded an email to Bayer from a company named Clean Harbors. The communication outlined a draft incident action plan to clean up after the pipe burst. The message does not indicate who hired Clean Harbors, but Macy continued to forward emails on the company's cleanup work to staff at Bayer.

A Bayer spokesperson confirmed the company "has been providing resources on the ground since mid-February supporting the State of Nebraska response team as they address the situation at the AltEn ethanol plant. Those efforts have included hiring an environmental remediation company to help AltEn respond to the February spill at the site. We have also commissioned the environmental remediation company to install three holding tanks with a storage capacity of more than 10 million gallons and begin the process of filtering and processing water in the storage lagoons onsite."


NDEE Environmental Engineer Hillary Stoll also reached out to experts in academia and others, questioning whether composting was an effective way to dispose of treated seed.

Stoll contacted Clyde Ogg, pesticide safety extension educator at the University of Nebraska-Lincoln, and a contributor to the pesticide stewardship website, asking for basic information about the safety of composting treated seed.

"I noticed at the bottom of the page it says that composting is never recommended for pesticide-treated seed," Stoll said in an email to Ogg.

"Would this also apply to byproducts from an ethanol process with high amounts of pesticides? I have started looking into this but wanted to reach out since you are an expert in this area."

Stoll also was put in contact with a stewardship manager for Syngenta based in North Carolina who trains people who treat the seeds.

In a March 2, 2021, email, the Syngenta manager said a key recommendation to customers is to "never compost treated seed," and "careful planning of the quantity of seed you need is essential since disposal of treated seed may be a problem."

See more of DTN's reporting on AltEn here:…, here:… and here:….

See more on DTN's reporting on how seed treatment use has increased steadily over the past decade:… and here:….

This article was reported by DTN Staff Reporters and Editors Chris Clayton, Todd Neeley and Emily Unglesbee.

They can be reached at,

Editor's Note: This story and related pieces will be updated as new information becomes available.