Groundwater investigations and monitoring are ongoing. The department continues to review and comment on groundwater and other monitoring results to determine next steps in investigation and cleanup. Investigation of groundwater conditions on- and off-site is continuing in the Ozark and Springfield aquifers, including installing additional monitoring/ extraction wells and testing existing monitoring wells. For additional information, please review the information under Future Activities.
Regular private drinking water well testing is ongoing. To date, Northrop Grumman and the department have collectively sampled more than 400 domestic-use wells near the former Litton facility. The cumulative number of sampled domestic wells continues to increase, as previously unknown wells are discovered and permission is granted by property owners to sample those wells.
During the 2023 third and fourth quarter domestic well sampling events, Northrop Grumman collected samples at 51 private well locations. Forty-eight additional wells were scheduled for sampling during this period; however, these wells were not sampled due to the lack of response from homeowners, homeowners declining to be sampled, house renovations underway, or lack of contact information for new homeowners. Of the 51 wells sampled, TCE was not detected above the reporting limit of 1 microgram per liter, or 1 part per billion (ppb) in 37 wells. Samples from 7 of 51 wells contained detectable concentrations of TCE or TCE breakdown products. However, all detections for these seven wells were below the respective TCE maximum contaminant level (MCL) of 5 ppb for drinking water use. Seven wells showed a TCE concentration above the MCL. Home water treatment systems were installed at those residences. Groundwater entering and exiting the treatment systems was tested and neither TCE nor TCE breakdown products were reported above the MCL in the samples collected following treatment.
The most recent domestic well sampling event that the department has final, validated results was conducted between mid-January 2024 and mid-March 2024. During this event, Northrop Grumman collected samples at 11 private wells. Fifteen wells in the program were not sampled because the property was vacant, or there was no response from homeowners to voicemails and door hangers after three or more attempts in the past year. Five other wells were not sampled due to no response from homeowners, lack of contact information for new homeowners, or the well was not functional. In 8 of 11 wells sampled during the first quarter of 2024, TCE and TCE degradation products were either not detected or were detected below 1 ppb. One well location had detections greater than 2 ppb, but less than 5 ppb. Two locations had detections greater than 5 ppb; however, no detections of TCE or TCE degradation products were reported in water samples taken at these locations after treatment using the home water treatment systems.
Multiple sampling events have provided a comprehensive data set for private wells in the area and the basis for periodic adjustment of the sampling frequency for those wells. A modified sampling scheme for private wells was developed based on this data and approved by the department in September 2021:
- Wells with TCE concentrations less than 2 ppb are sampled yearly, except that any wells demonstrating an “increasing” or “probably increasing” contamination trend are sampled twice a year, regardless of TCE concentration.
- Wells with TCE concentrations greater than 2 ppb are sampled twice a year.
- Wells with detections of only TCE breakdown products are sampled yearly.
- Wells with no TCE or TCE breakdown products are sampled on a quarterly or semi-annual rotating basis for a total of one sample per each of the wells every two years. The rotating sampling effort is designed to ensure that non-detect wells within one-quarter mile of wells with positive detections are sampled during each rotational sampling event.
- Any new wells where detections of TCE or TCE breakdown products are present during the initial sampling event are sampled every three months for the first year. This is done in order to have a full year of data to determine potential concentration variations and to properly place these wells in the correct sampling tier.
- Any new wells without detections during the initial sampling event are placed in the two-year sampling rotation, unless circumstances indicate that more frequent sampling is necessary in specific instances.
On-site soil cleanup. Northrop Grumman recently completed soil cleanup in two areas. The department approved Northrop Grumman’s soil cleanup completion report for the former Sanitary Lagoon in October 2021. Northrop Grumman submitted a soil cleanup completion report to the department in September 2022 for the former building sub-floor. The department approved this report in November 2022. Northrup Grumman submitted the Final Report Documenting Completion of Soils Remediation in July 2023 and response to the department’s comments on this report in February 2024. This report and associated response to comments was approved in June 2024.
Groundwater cleanup continues. Northrop Grumman continues to pump and treat groundwater from the Springfield-Plateau (shallow) and Ozark (deep) aquifers to remove TCE. The Springfield-Plateau extraction well system consists of five wells. The Ozark aquifer extraction well system consists of two wells. During the fourth quarter of 2023, approximately 771 thousand gallons of groundwater were extracted from the Springfield-Plateau aquifer. Groundwater was treated on-site and discharged to the Springfield sanitary sewer system. During the fourth quarter of 2023, approximately 11.7 million gallons of groundwater were extracted from the Ozark aquifer, treated on-site and discharged to the Springfield sanitary sewer system. Approximately 44 pounds of VOCs were removed from the groundwater during the fourth quarter of 2023. By the end of the fourth quarter 2023, approximately 998.5 pounds of VOCs have been removed from the groundwater since the groundwater extraction systems began operating in June 2019.
Further improvements to the groundwater treatment systems at the site continue. Treatment building upgrades and regularly scheduled operation, maintenance and monitoring of the groundwater treatment systems is ongoing. The department previously approved Northrop Grumman’s multi-phase extraction (MPE) pilot testing to assess enhanced removal of TCE from the Springfield-Plateau aquifer. Northrop Grumman submitted an MPE pilot test report to the department in May 2022. The department reviewed and commented on this report in September 2022. Northrup Grumman submitted a response to the department's comments in October 2022. Expanded use of MPE for cleanup of VOCs remains under consideration.
Mitigation systems in place at Fantastic Caverns. Northrop Grumman and Fantastic Caverns entered into agreements to coordinate ongoing sampling and mitigation efforts at Fantastic Caverns. Fantastic Caverns representatives installed and continue to operate mitigation systems, in coordination with Northrop Grumman. Ongoing air sampling in the caverns confirms the mitigation systems were successfully implemented and safe air levels are being maintained in the toured portions of the caverns. Northrop Grumman and Fantastic Caverns regularly submit reports to the department, presenting the data collected and documenting ongoing mitigation and testing efforts.
Time Critical Removal Action (TCRA) to address groundwater. As investigations proceed towards a final remedy for groundwater, interim actions are often taken to address potentially unacceptable exposures to contaminated groundwater identified through these investigations. As a short-term solution, Northrop Grumman installed, and continues to maintain, granular activated carbon treatment systems in homes where wells have exceeded the TCE MCL. As a long-term solution, Northrup Grumman recently proposed a TCRA to address three private water supply wells that have consistently had concentrations of TCE above the MCL. As part of the department-approved TCRA, the city of Springfield public water supply is being extended to two residences where the private wells have been impacted above the MCL for TCE. Once the residences are connected to city water, these wells will be properly decommissioned according to the state well regulations. At the third private water supply well location, Northrup Grumman will install a deeper private water supply well to access clean water and properly decommission the contaminated well according to the state well regulations.
What if I'm not in the area of interest, but want to have my well tested myself?
Local Laboratory
Pace Analytical Services LLC in Springfield takes walk-in requests and provides residents with containers to collect samples, along with an instruction sheet and a chain-of-custody form. The resident will pay upfront for the EPA Method 524.2 VOC drinking water analysis, which is approximately $250 plus an additional 8.6% economic fee. The samples are sent to the certified Pace Analytical Services Lab located in Peoria, Illinois. Turnaround time for sample results is about eight business days. Sample results will be sent directly to the individual requesting sampling.
Pace Analytical Services LLC
1805 W. Sunset St.
Springfield, MO 65807
Phone:417-864-8924
Contact: Janet Clutters by email at janet.clutters@pacelabs.com
Other Laboratories
These certified chemical laboratories are also capable of performing analyses of private water samples.
What if I have TCE in my water below the MCL and I want to install a treatment system myself?
The department does not recommend specific types of water treatment systems or a companies that sell water treatment systems; however, the following local companies sell and install whole house water treatment systems:
The National Sanitation Foundation (NSF) tests and certifies water treatment systems for reducing specific contaminants in drinking water:
Related Links
Health Questionnaire
The Missouri Department of Health and Senior Services (DHSS) sent out a questionnaire in early 2020 to gather input on community concerns and information on how best to communicate with the community. A total of 353 questionnaires were sent out and 94 were returned. Information gathered through the questionnaires will be shared with the community as part of DHSS’s public health consultation, which will evaluate community exposures to TCE in private well water. DHSS is preparing the public health consultation and they anticipate releasing the information in the next few months.
Community Involvement Plan
Public Meetings
Nov. 7, 2019
The Missouri Department of Natural Resources invited the public to an open house and informational meeting about the former Litton Systems Inc. site in Springfield and the former Electro-Pac site in Willard. The meeting was held at the Relics Event Center in Springfield.
March 14, 2019
The Missouri Department of Natural Resources held an informational meeting about the former Litton Systems Inc. site at the Ozark Empire Fairgrounds and Event Center in Springfield.
Activities scheduled for 2024 and beyond:
- Continue extracting and treating groundwater from the Springfield Plateau and Ozark aquifers, and discharge treated groundwater to the Springfield sanitary sewer system — potential reinjection of treated groundwater into the Ozark aquifer is being considered
- Performing regularly scheduled operation, maintenance and monitoring for the Springfield Plateau and Ozark aquifer treatment systems
- Performing regularly scheduled maintenance and sampling of private well treatment systems
- Performing regularly scheduled sampling and analysis of groundwater from private wells and site-specific monitoring wells
- Continue evaluating the Springfield Plateau aquifer contamination through installing additional exploratory borings and groundwater grab sampling
- Collecting and analyzing samples from several springs located in proximity to the site
- Removing sediment and collecting and analyzing groundwater samples from the lower portion of the MWO-09 borehole, located on the Springfield Branson National Airport property
- Evaluating local caves and springs within the area of interest to assess the potential for human and environmental receptor exposure to contaminants from the site
- Submitting reports for ongoing activities
Northrop Grumman continues working toward developing a final remedy for the groundwater contamination. Ongoing investigations, including continued sampling and analysis of groundwater from private wells, expanding the Springfield Plateau and Ozark aquifer treatment systems and considering additional, potentially viable treatment technologies are integral to this strategy. Northrop Grumman will continue discussions with the department as they collect information and propose actions to determine the appropriate next steps in working towards a final remedy.
