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EPA in Nebraska

O’Neill Groundwater Superfund Site, O’Neill, Holt County, Nebraska - Fact Sheet, November 2018

Site Assessment and Evaluation


O’Neill (2010 population of 3,705) is in Holt County, near the northeastern extent of the Sandhills region in north-central Nebraska.  Past environmental investigations conducted by the U.S. Environmental Protection Agency (EPA), in coordination with the Nebraska Department of Environmental Quality, included collection of groundwater and soil samples. These samples were analyzed for volatile organic compounds (VOCs) and pesticides. The most recent sampling conducted in July 2018 documented trichloroethylene (TCE) contamination of groundwater.


Known groundwater contamination at the site is associated with historical industrial practices. Facilities that utilized hazardous substances for manufacturing, dry cleaning, automotive repair, and parts degreasing are common sources. Previous groundwater assessment activities in the area included the investigation of former grain storage areas in 1996. This site was named the O’Neill U.S. Department of Agriculture Grain Bin Site (EPA ID No. NEN000705746).


EPA will perform additional groundwater and vapor intrusion (subsurface intrusion) sampling to investigate any threats to human health and the environment and to determine if potential exposure pathways are present. The assessment will include further characterization of the nature and extent of contaminants in groundwater. Vapor intrusion samples will also be taken to determine if hazardous vapors related to the site are present in the subsurface soils.


Concentrations of TCE were identified above EPA screening levels, warranting further investigation. Exposure to high levels of TCE may cause adverse impact to the nervous system, changes in the rhythm of the heartbeat, and liver damage. Some human studies indicate that TCE may cause developmental effects such as congenital heart defects, central nervous system defects, and small birth weight. There is strong evidence that TCE can cause kidney cancer in people and some evidence that it causes liver cancer and malignant lymphoma (a blood cancer).


For questions or site information, contact:

Manuel Schmaedick
On-Scene Coordinator
U.S. EPA Region 7
11201 Renner Boulevard
Lenexa, KS 66219
Phone: 913-551-7449
Toll-free: 1-800-223-0425
Pamela Houston
Community Engagement Specialist
U.S. EPA Region 7
11201 Renner Boulevard
Lenexa, KS 66219
Phone: 913-551-7699
Toll-free: 1-800-223-0425