Last updated April 6, 2017

Zill LLC (Inner City Oil Inc. Gasoline Station) 3814 East 31st St., Kansas City, Mo, Jackson County
ST8310, R8771 & R9048

The Zill LLC site is a gasoline station located at 3814 E. 31st St. in Kansas City, Mo. Petroleum contamination associated with the operation of an underground storage tank system has been found at this site. This webpage has been established to provide information to the public regarding the actions taken by the department and Zill LLC (through their environmental consulting firms MHS Environmental Inc. and APEX Envirotech Inc.) to address the petroleum contamination at this site. 

Background and Timeline of Activities

Since at least 1967, this site has been a gasoline station that sold gasoline and diesel fuel. In September 2006, the old steel tanks were removed and replaced with new fiberglass tanks. [Dec. 8, 2006, Underground Storage Tank Closure Report prepared by MHS Environmental Inc.] Petroleum contamination was found during the removal of the tanks. Although 805 tons of petroleum impacted soil was removed from the site and properly disposed, Zill LLC was unable to remove all of the contamination, leaving levels of petroleum contamination above the department’s default target levels at the bottom of the tank pit and in the area of the product lines and dispensers. As a result, the department required Zill LLC to conduct an investigation, or site characterization, at the site to determine the extent of contamination remaining in soils and groundwater and to address the contamination in accordance with the 2013 Missouri Risk-Based Corrective Action (MRBCA) Guidance for Petroleum Storage Tank Sites. A work plan for conducting the site characterization activities was submitted by APEX and approved by the department on Oct. 9, 2013. 

The department also required Zill LLC to conduct investigation and mitigation activities needed to address complaints of petroleum vapors in nearby residences and businesses. These included, but were not limited to, the installation of interceptor trenches and repairs to sewer lines, sewer laterals and indoor plumbing. Affected residents were also temporarily relocated during the vapor mitigation period. 

Visit the department's Cleveland Avenue and 31st Street website for additional information
regarding the department's Environmental Emergency Response to three
incidents involving petroleum odors.

In December 2013, APEX conducted a subsurface investigation at the site to define the extent of remaining contamination including the installation of nine soil borings and five groundwater monitoring wells. [Jan. 8, 2014, Site Characterization Report prepared by APEX.] The soil and groundwater samples collected showed significant contamination to the south and west of the underground storage tank system. Petroleum was also found in two of the newly installed monitoring wells. The sampling activities, however, did not determine the full extent of the petroleum plume or the soil and groundwater contamination. A work plan for conducting the additional site characterization activities was submitted by APEX and approved by the department on Oct. 2, 2014.

In November 2014, APEX conducted additional sampling at the site to further define the extent of the petroleum plume as well as the contamination in soil and groundwater. This included the installation of an additional seven soil borings and three groundwater monitoring wells. [March 13, 2015, Site Characterization Report prepared by APEX.] Based upon the data collected, the extent of the petroleum plume and soil and groundwater contamination is still not defined. Additional borings and wells are needed to define the extent contamination. 

In June 2015, APEX conducted additional sampling at the site to help define the extent of contamination. This included the installation of nine soil borings and monitoring wells. Based upon the results of this investigation, the extent of contamination is still not known and further borings and wells are needed. [August 24, 2015, Site Characterization Report prepared by APEX]

On June 11, 2015, the department collected free product samples from three of the groundwater monitoring wells at this site for laboratory analysis. The results of the samples indicate the product present in each of these wells originated from the same source. [July 20, 2015, Laboratory Analytical Report prepared by Pace Analytical laboratory]

On July 22, 2015, the department surveyed and gauged the groundwater monitoring wells at the site and created a groundwater elevation map, which illustrates the groundwater flow direction for the site. [Groundwater gauging data table and the piezometric map.]

On Aug. 4, 2015, during a site visit, the department observed APEX conducted a groundwater gauging event to check for the presence of free product in the groundwater monitoring wells. Based upon the results of the gauging event, free product continues to be present in the tank pit observation wells and monitoring wells 7, 9, 10 and B. [Aug. 4, 2015, Site Visit Summary prepared by MoDNR]

Tank sites near cleveland avenue

On Sept. 18, 2015, the department issued a Notice of Violation to Zill LLC for failure to investigate a suspected release and for failure to install and maintain corrosion protection for the UST system. [Sept. 18, 2015, Notice Of Violation #1730 TE issued by the department]

On Nov. 5, 2015, the department excavated a portion of the sewer main at 3023 Cleveland Ave. and made repairs to an area of sewer that was allowing petroleum-impacted groundwater to enter the utility. 

On Nov. 11-12, 2015, Zill conducted two High Vacuum Extraction events to recover free phase product from a number of on-site and off-site monitoring wells. During these two events, petroleum contamination equivalent to approximately 280 gallons of gasoline was removed from the subsurface. A report documenting these activities is posted below.

From Nov. 23, 2015, to Dec. 5, 2015, Zill conducted a tightness test to determine if the underground storage tank system at this site was leaking. The test, conducted by Leak Detection Technologies, determined that one of the underground tanks was leaking at a rate of 0.05 gallons per hour. As a result, the tank has been emptied and taken out of service.   

On Dec. 28, 2015, the department oversaw a video inspection of the sewer main that runs between 3023 Cleveland Ave. and 3001 Cleveland Ave. to evaluate the integrity of the sewer connections along this stretch of main. This work was conducted as a part of continuing efforts to stop the infiltration of petroleum impacted groundwater into the sewer and the resulting vapor problems in nearby homes and businesses. 

During Aug. 1-5, 2016, Zill conducted groundwater investigation activities including gauging to check for the presence of free product and sampling the groundwater monitoring wells at the site visit. The department was on-site to observe some of this work.  [Oct. 11, 2016, Groundwater Investigation Summary Report prepared by GEI Consultants Inc.]

NewDuring Aug. 3-4, 2016, Zill collected free product samples from the groundwater monitoring wells and a product sample from a dispenser at the site for chemical analysis. [Feb. 28, 2017, Non-Aqueous Phase Liquid (NAPL) Forensic Analysis Summary Report prepared by GEI Consultants Inc.

NewAug. 22, 2016, the department attended a public meeting regarding the site.

NewOct. 6, 2016, the department attended a public meeting regarding the site. Additionally, Zill collected additional product samples from a dispenser and a groundwater monitoring well at the site. [Feb. 28, 2017, Non-Aqueous Phase Liquid (NAPL) Forensic Analysis Summary Report prepared by GEI Consultants Inc.]

NewOct. 27, 2016, the department attended a public meeting to provide updates to interested citizens regarding the status of the site.

NewMarch 20, 2017, the department attended a public meeting regarding the site.

NewApril 1, 2017, the department attended a public meeting regarding the site.

Next Steps - Ongoing Activities and Projected Schedule

The department will continue to direct the investigation and oversee cleanup activities conducted by Zill LLC's consultant. Anticipated milestones and reporting deadlines are summarized below:

  • Within 90 days of the department’s concurrence that the extent of contamination has been defined, Zill LLC must submit a risk assessment evaluating the danger the contamination poses to human health and the environment under current and future conditions in accordance with the 2013 MRBCA guidance. 

  • Within 90 days of the department’s acceptance of the risk assessment report, Zill LLC must submit a corrective action plan to address any remaining petroleum and other contamination that poses an unacceptable level of risk to current or future receptors.

  • Zill LLC must remediate the site in accordance with the approved corrective action plan and continue removing the petroleum until as much as practicable has been removed in accordance with the Missouri Petroleum Storage Tank Law and regulations. Reports documenting the site remediation and petroleum recovery activities must be submitted on a quarterly basis. 

Data and Reports

Site information and sampling data collected during the tank closure activities and subsequent investigations into the extent of contamination are provided in the documents posted below. This list will be updated as new information and reports are received.

Press Releases

More Information

Visit the department's Cleveland Ave. and East 31st St. website for more information regarding the department's Environmental Emergency Response to petroleum odor complaints in this area. The department will continue to update this webpage as information becomes available. Should you have questions, please contact one of the following agencies or staff members

Department of Natural Resources

Media inquires should be directed to the Communications Office at the Department of Natural Resources at 800-361-4827 or 573-751-1010 or by email.

All general questions regarding the site may be directed to the Underground Storage Tanks section of the Department of Natural Resources at 800-361-4827.

Health Related Questions

  • Missouri Department of Health and Senior Services, Bureau of Environmental Epidemiology, 573-751-6102 or by email.
  • Kansas City Department of Health at 816-513-6008 or by email to health@kcmo.org.

Return to the Cleveland Ave. and East 31st St. Investigation Main Site