Nustar Pipeline Release, North Andover Site

Site History

In June 2012 a homeowner in the Quail Crossing neighborhood in Andover, Kansas, reported a strong petroleum odor from his irrigation well while performing routine maintenance. The homeowner contacted NuStar Pipeline Operating Company, LLC (NuStar), who operates a petroleum transportation pipeline that passes approximately 50 feet from the home, located in Colt Court. KDHE received notification of the problem and was present when NuStar representatives confirmed the presence of petroleum products in the well. Analysis of a sample collected from the well showed detections of total petroleum hydrocarbons and volatile organic compounds at levels above the federal maximum contaminant levels (MCLs) for drinking water and KDHE's Tier 2 Levels for groundwater. Six other nearby irrigation wells were checked with field equipment, and no signs of impact were observed in those wells. NuStar had the sprinkler system for the impacted well connected to the Andover public water supply.Installing monitoring wells to track groundwater flow and contaminant migration.

NuStar conducted tests and identified a leak in a section of the pipeline located beneath West Mountain, adjacent to the property of the impacted irrigation well. In July 2012 significant soil impact in a 50-foot section was discovered, and approximately 16 cubic yards of impacted soil was excavated when the pipeline was repaired. Sample results show that soil and groundwater adjacent to the pipeline have been impacted.

Product recovery from the impacted irrigation well continued on a periodic basis during negotiations between the KDHE and NuStar for a Consent Agreement and Final Order. Over 230 gallons of petroleum product were recovered as of October 2013.

After the Consent Agreement and Final Order was executed in May 2013, NuStar began investigating the extent of petroleum contamination in soil and groundwater. The first phase of the work was conducted in July 2013 with expanded efforts continuing into October 2013 to delineate the area of contamination.

Investigation Plans & Findings

Nine monitoring wells were installed in August 2013, and an additional seven monitoring wells were installed in September 2013. Results show that the groundwater flows to the east-northeast, which is generally consistent with the wells that show impact.
A nearby lake is not impacted by the petroleum contamination.

The lake, located to the south of the contamination, was evaluated for impacts from the pipeline leak. A gauge was installed to study the relationship between the lake and the groundwater. Information gathered has shown that the lake is a "losing" lake, which means groundwater is not flowing into it, but rather, the lake is pushing the groundwater in the northeasterly direction. To date, data show that the impacted groundwater is moving away from the lake.

Irrigation wells have been sampled in the vicinity and additional wells are continuing to be sampled. To date, irrigation wells that have shown detections of contaminants are located in Colt Court, West Mountain (near the area where the leak occurred), and Ruger Circle. With the permission of the well owners, all sprinkler systems connected to impacted wells and other wells nearby were connected to the public water supply.

In October 2013, 16 monitoring wells and 15 irrigation wells in the area of the investigation were sampled. The results were compiled and evaluated in the Comprehensive Investigation Report (PDF). A pilot test to evaluate a clean-up alternative (soil vapor extraction) was conducted in November 2013. Additional soil testing was conducted in April 2014 to help evaluate the best approaches to address residual soil contamination. NuStar also performed pilot testing to evaluate in-situ groundwater remediation in spring 2015. Tests to evaluate the potential for vapors to enter homes were initiated in December 2013. Additional excavation activities were completed in October 2015 to remove additional soils in the release area. Results are documented in the March 2016 Soil Excavation Results Report (PDF).

Two groundwater pilot tests have been conducted to evaluate groundwater remedial technology for treating the impacted groundwater. The initial phase of the pilot test was performed from March through June 2015. Three additional monitoring wells (MW-17, MW-18, and MW-19) were installed and an oxygen release compound (ORC) was injected through nine temporary injection borings. Positive results from this injection test prompted a follow-up expanded groundwater pilot test from July 2016 through September 2017. The expanded pilot test included the introduction of a more concentrated pelletized form of ORC Advanced and the installation of a larger number of injection borings to address residual dissolved-phase petroleum constituents in groundwater.

NuStar completed a Corrective Action Study (PDF) (February 4, 2019) that recommends corrective action alternatives for addressing the residual petroleum hydrocarbons in soil and groundwater.

Community Involvement

Ongoing input and involvement by citizens is essential to KDHE's efforts to provide effective community engagement. Community members need to be involved in all phases of the investigation and remediation process so that contamination is addressed in a way that protects people and the environment - now and in the future. KDHE has developed a Community Involvement Plan (PDF) to encourage community involvement in site activities.

On August 29, 2013, and February 17, 2014, residents attended neighborhood meetings where KDHE and NuStar provided investigation results, discussed the next steps for investigation and cleanup, and listened to community concerns.

KDHE held a public meeting on June 12, 2019, at the Andover Public Library to present KDHE's draft Corrective Action Decision, which presented the preferred remedy, and to solicit public participation. KDHE selected a final remedy after reviewing and considering all information submitted during the 30-day public comment period held May 20, 2019, through June 20, 2019. The Final Corrective Action Decision (PDF) was signed by the KDHE Secretary on July 20, 2019.

Current & Anticipated Activities

Homeowners in the Quail Crossing neighborhood use private wells for irrigation purposes. NuStar has connected sprinkler systems to the municipal water supply for residences whose wells show impact from the contamination as well as residences with unimpacted wells that might affect the migration of the contamination when in use. Irrigation wells may be sampled periodically to assist in evaluating changes in the impacted groundwater.

KDHE issued the Final Corrective Action Decision (PDF) with the selection of the preferred remedy of enhanced aerobic bioremediation via injection of ORC. NuStar submitted the Corrective Action Plan outlining how the preferred remedy will be implemented, and it was approved by KDHE on October 4, 2019. The plan was initiated in late October 2019 and drilling activities for the injections were completed in December 2019. Groundwater continues to be sampled quarterly to assess the effectiveness of ongoing in-situ groundwater treatment and to monitor contamination.

Additional Information

For additional information, please contact:
Pamela Green, Environmental Specialist
Remedial Section/Site Remediation Unit
KDHE Bureau of Environmental Remediation
Curtis State Office Building
1000 SW Jackson Street
Suite 410
Topeka, KS 66612-1367
Phone: 785-296-1935
Email Pamela Green

Further Information About Contamination & Remedial Strategies

Site Documents

  1. First Semi-Annual 2022 Groundwater Monitoring Report, May 13, 2022
  2. Fourth Quarter 2014 Groundwater Monitoring Report, February 10, 2015 (PDF)
  3. Neighborhood Meeting PowerPoint Presentation, August 29, 2013 (PDF)
  4. Consent Agreement and Final Order, May 10, 2013 (PDF)
  5. Community Involvement Plan, November 2013 (PDF)
  6. Revised Groundwater Investigation Work Plan Addendum, September 20, 2013 (PDF)
  7. Initial Response Summary, July 29, 2012 (PDF)
  8. Table of Product Recovery Amounts from Well, August 2013 (PDF)
  9. Revised Groundwater Investigation Work Plan Addendum, September 20, 2013 (PDF)
  10. Soil Excavation Results Report (PDF)
  11. Soil Vapor Extraction Pilot Test Work Plan, November 15, 2013 (PDF)
  12. Neighborhood Meeting PowerPoint Presentation by Apex, February 17, 2014 (PDF)
  13. Corrective Action Plan, September 10, 2019 (PDF)
  14. Corrective Action Implementation Report, February 12, 2020 (PDF)
  15. Corrective Action Study (PDF)
  16. Second Quarter 2015 Groundwater Monitoring Report, Part 1, November 6, 2015 (PDF)
  17. Second Quarter 2015 Groundwater Monitoring Report, Part 2, November 6, 2015 (PDF)
  18. Excavation Work Plan, August 19, 2015 (PDF)
  19. Expanded Groundwater Pilot Test Report (Revised) Part 1, January 24, 2018 (PDF)
  20. Expanded Groundwater Pilot Test Report (Revised) Part 2, January 24, 2018 (PDF)
  21. Final Corrective Action Decision, June 25, 2019 (PDF)
  22. Groundwater Pilot Test Work Plan, January 16, 2015 (PDF)
  23. Neighborhood Meeting PowerPoint Presentation by KDHE, February 17, 2014 (.pdf)
  24. Revised Groundwater Pilot Test Report and Expanded Pilot Test Work Plan, May 17, 2016 (PDF)
  25. Revised Interim Groundwater Pilot Test Implementation Report, Part 1, October 22, 2015 (PDF)
  26. Revised Interim Groundwater Pilot Test Implementation Report, Part 2, October 22, 2015 (PDF)
  27. Proposed Separate-Phase Hydrocarbon Removal Modification, January 6, 2015 (.pdf)
  28. First Quarter 2016 Groundwater Monitoring Report, August 4, 2016 (PDF)
  29. First Quarter 2017 Groundwater Monitoring Report, May 24, 2017 (PDF)
  30. First Quarter 2018 Groundwater Monitoring Report, June 15, 2018 (PDF)
  31. First Quarter 2019 Groundwater Monitoring Report, May 7, 2019 (PDF)
  32. First Quarter 2020 Groundwater Monitoring Report, July 14, 2020 (PDF)
  33. First Quarter 2021 Groundwater Monitoring Report, May 7, 2021 (PDF)
  34. Second Quarter 2016 Groundwater Monitoring Report, October 27, 2016 (PDF)
  35. Second Quarter 2017 Groundwater Monitoring Report, August 7, 2017 (PDF)
  36. Second Quarter 2018 Groundwater Monitoring Report, August 21, 2018 (PDF)
  37. Second Quarter 2019 Groundwater Monitoring Report, August 23, 2019 (PDF)
  38. Second Quarter 2020 Groundwater Monitoring Report, September 1, 2020 (PDF)
  39. Second Quarter 2021 Groundwater Monitoring Report, August 24, 2021 (PDF)
  40. Third Quarter 2015 Groundwater Monitoring Report, February 1, 2016 (PDF)
  41. Third Quarter 2016 Groundwater Monitoring Report, February 9, 2017 (PDF)
  42. Third Quarter 2017 Groundwater Monitoring Report, November 22, 2017 (PDF)
  43. Third Quarter 2018 Groundwater Monitoring Report, December 14, 2018 (PDF)
  44. Third Quarter 2019 Groundwater Monitoring Report, November 22, 2019 (PDF)
  45. Third Quarter 2020 Groundwater Monitoring Report, September 1, 2020 (PDF)
  46. Fourth Quarter 2015 Groundwater Monitoring Report, April 28, 2016 (PDF)
  47. Fourth Quarter 2016 Groundwater Monitoring Report, February 13, 2017 (PDF)
  48. Fourth Quarter 2017 Groundwater Monitoring Report, March 1, 2018 (PDF)
  49. Fourth Quarter 2018 Groundwater Monitoring Report, January 25, 2019 (PDF)
  50. Fourth Quarter 2019 Groundwater Monitoring Report, July 10, 2020 (PDF)
  51. Fourth Quarter 2020 Groundwater Monitoring Report, April 5, 2021 (PDF)
  52. Soil Investigation Report and Proposed Soil Excavation Work Plan, July 17, 2014 (PDF)
  53. Soil Vapor Extraction Evaluation and Proposed Soil Investigation Report, March 28, 2014 (PDF)
  54. Vapor Intrusion Conceptual Site Model, July 5, 2018 (PDF)
  55. Modified Irrigation Well Sampling Program Work Plan (Revised), January 4, 2018 (PDF)
  56. Comprehensive Investigation Report (PDF)
  57. First Quarter 2014 Groundwater Monitoring Report, May 2, 2014 (PDF)
  58. First Quarter 2015 Groundwater Monitoring Report, April 15, 2015 (PDF)
  59. Second Quarter 2014 Groundwater Monitoring Report, July 9, 2014 (PDF)
  60. Third Quarter 2014 Groundwater Monitoring Report, October 20, 2014 (PDF)