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Onizuka Village Project

During the Onizuka Village housing redevelopment in 2009, petroleum affected soil was found in several of the excavation locations (as indicated by red asterisks in image [right]) between nine and eleven feet below ground surface. The find was reported to the Hawaii Department of Health (DOH). After consultation with the DOH, and preliminary assessment of the information available at the time of the site, redevelopment continued. While a health hazard is not anticipated, the Navy must perform due diligence by investigating the site using DOH standards and ensuring that we are protective of human health and the environment. In order to complete its assessment, NAVFAC Hawaii will collect samples in Onizuka Village starting in January 2013. Please be assured there is no health risk to residents as a result of the work being conducted. In addition, it is important to note that your drinking water comes from fresh water aquifers located off base and is completely safe.
NAVFAC Hawaii - The Navy has a program which investigates and remediates sites where there is contamination from past military practices. The Navy’s agent in Hawaii to conduct these studies and remediation of such sites is Naval Facilities Engineering Command (NAVFAC) Hawaii.

This image, taken in 1952, provides an overlay of the former flightline area and the current Onizuka Village housing area on Joint Base Pearl Harbor-Hickam.


Fact Sheet - Onizuka Village Treatability Study - July 2017
Fact Sheet - Onizuka Village Treatability Study - June 2014
Fact Sheet - Onizuka Village Supplemental Remedial Investigation - December 2013
Fact Sheet - Onizuka Village Background, Remedial Investigation & Upcoming Work - July 2013
Fact Sheet - Onizuka Village Background & Remedial Investigation - January 2013


Remedial Investigation Schedule & Activities
May 2021 - The Navy continues the established sampling and assessment routine. This is the third of four scheduled events since the SVE system shut down in June 2020. Sampling event to be held the week of May 24.
December 2020 - Due to observed soil vapor levels dropping below the project cleanup goals, the SVE system was shut down in June 2020.  There is currently a 2-year plan to continue soil vapor sampling and monitor the site at 6-month intervals to see if the soil vapor levels rebound. If after two years of monitoring the soil vapor levels remain low, a determination will be made as to whether resuming SVE system operations is necessary.
December 2019 - The Navy continued the established sampling and assessment routine as described in 2018.
December 2018 - Soil Vapor Sampling Collection from select areas of Onizuka Village. Fieldwork is scheduled to begin on Dec. 10. The work is expected to take approximately ten business days. Each work area and sampling location will be delineated with cones and caution tape. The purpose of this sampling is to provide the Navy and State of Hawaii Department of Health with sufficient information to determine the appropriate action to take at the site. Based on the investigation data collected to date, there are no health risks to residents; however, further monitoring is being conducted to confirm these findings and to better assess the remediation system.
July 2017 - Treatability Study Fact Sheet posted (above).
June 2016 - Annual soil vapor sampling planned for beneath the concrete slabs (subslab samples) in twenty eight (28) homes and semi-annual soil vapor sampling at twenty-two (22) exterior soil vapor monitoring locations within Onizuka Village. Sample collection is expected to take approximately seven (7) business days starting June 13, 2016. All actions will be coordinated with Hickam Communities to gain access to the 28 garages without inconveniencing those residents. Plans are to continue soil vapor monitoring to verify safe conditions.
February 2016 - Semi-annual monitoring completed at twenty-two (22) exterior soil vapor monitoring locations within Onizuka Village. Data used for evaluating concentration trends and effectiveness of Soil Vapor Extraction (SVE) remediation. Soil vapor sample results indicate that concentrations are stable or decreasing. The SVE system continues to operate with the goal of reducing concentrations in soil vapor. Data shows that there are no health risks posed to residents related to petroleum contamination at the site. The State of Hawaii Department of Health concurs with plans to continue subslab soil vapor monitoring (samples from garages) on an annual basis.
December 2015 & January 2016 - Soil vapor sampled at select garages (subslab samples) and exterior monitoring points to monitor effectiveness of the Soil Vapor Extraction (SVE) system at reducing soil vapor concentrations and to verify there is no vapor intrusion into homes.
September 2015 - New batteries were installed and the Soil Vapor Extraction (SVE) system was restarted. Repairs are ongoing.
August 2015 - Soil gas sampling was completed in specifically identified locations and select garages (subslab samples) to verify conditions are acceptable. Preliminary results show no vapor intrusion into homes.
March 11, 2015 - Semi-annual on-going soil vapor sampling beneath the concrete slabs in twenty-eight (28) homes and eight (8) exterior locations within Onizuka Village started. Results will be available once received from the lab in approximately six (6) to eight (8) weeks. Based on the investigation data collected to date, there are no health risk to residents; however, the semi-annual monitoring is being conducted to confirm these findings.
February 19, 2015 - It was determined that at least two batteries had lost capacity within the Soil Vapor Extraction (SVE) system which resulted in taking the system offline to inspect the condition of the batteries and complete additional independent inspections of the system wiring and components. Trouble shooting is continuing and a fix is being aggressively pursued. This temporary setback is not causing any health risk to the residents. We will update this website when the system is fully operational again.
January 16, 2015 - The Soil Vapor Extraction (SVE) unit started up and is fully operating as designed.
October 20, 2014 - A soil vapor extraction system is currently being installed to remove subsurface vapors and prevent them from migrating beneath the buildings. Pressure monitoring using the previously installed sampling port in several garages will be used to check the pressure below ground surface within Onizuka Village to evaluate the system's efficiency.
August 18, 2014 - Semi-annual on-going soil vapor sampling beneath the concrete slabs in twenty-eight (28) homes and eight (8) exterior locations within Onizuka Village started. Results will be available once received from the lab in approximately six (6) to eight (8) weeks. Based on the investigation data collected to date, there are no health risk to residents; however, the semi-annual monitoring is being conducted to confirm these findings.
June 2014 - Feasibility Study (FS) Report for Subsite ST32 Onizuka Village was finalized. The overall objective of this FS was to evaluate various cleanup alternatives and to select the best alternative to provide a long-term, effective remedy that will reduce potential risks to human health. In consultation with Hawaii Department of Health (HDOH), and with input from the public, the Navy evaluated a variety of remedial alternatives to select an appropriate remedy for Subsite ST32 Onizuka Village. Of the various alternatives considered, Alternative 4 - Soil Vapor Extraction (SVE), Land Use Controls ( LUCs), and Long Term Monitoring (LTM) was recommended as the preferred alternative.
May 19, 2014 - Construction began to install three (3) horizontal wells using horizontal direction drilling In accordance with the Final Treatability Study Implementation Plan for Subsite ST32 Onizuka Village.
May 16, 2014 – Mailed letters to all residents explaining the installation of a Soil Vapor Extraction (SVE) system that will remove and treat elevated soil vapor. Action will begin May 19 with contractor workers onsite performing utility surveys and marking drilling locations. Drilling efforts are scheduled from June - July 2014. SVE startup is anticipated in September 2014.
December 9, 2013 – A Pearl Harbor Restoration Advisory Board meeting was held during which Onizuka Village was presented. Please see the December 2013 Fact Sheet for current information.
November 13, 2013 – The draft remedial investigation report for Onizuka Village is available for public comment through Dec. 13, 2013. This report presents the soil, soil vapor, and groundwater results from the study of petroleum affected soil at Onizuka Village. To receive an electronic copy, please contact Ms. Jocelyn Tamashiro at
September 16, 2013 – Letters were sent to residents of the seven buildings involved in Phase III sampling with the following information. Phase III sample results beneath 28 residences indicate low levels of petroleum are present in soil gas beneath the buildings; however, the levels are well below the screening criteria, indicating there is negligible risk of petroleum vapors entering the homes. The Navy will continue to collect soil gas samples from these residences every six months to verify that petroleum concentrations remain low beneath the buildings.
Sample results at seven locations outside the residences confirmed that petroleum vapors at 4 to 6 feet below the ground do exceed screening criteria. There is no danger to residents given the digging restrictions and depth of the vapors. As a result of these exceedances, the Navy is evaluating cleanup alternatives to remediate the deeper soil gas and prevent it from accumulating beneath any nearby buildings. Once a cleanup method is selected, the Navy will hold an Open House to notify residents about work locations and durations. Work to install a cleanup system is expected to start after February 2014.
July 22 - August 2013 – Phase III work will focus on seven buildings where sub-slab vapor samples will be taken from beneath the foundation of the structures. To do this, a two step process will occur. First, a small hole will be made into the garage floor and sub-slab sampling port installed. The sampling ports will have seals that are closed unless sampling is performed. Next, a sub-slab air sample will be collected a few days later. All actions will be coordinated with Hickam Communities to gain access to resident garage areas without inconveniencing the resident.
July 18, 2013 – Open House from 5 p.m. - 7 p.m. at Earhart Community Center. (Three residents attended. Two called to ask questions.)
July 11, 2013 – Letters to all residents mailed (28 specifically hand delivered to the residents of the seven buildings where Phase III work will occur between Gemini Avenue and Freedom Avenue, and near Lewamawaho Loop and Opulepule Alley.)
June 11 - End June 2013 – Due to testing results received from Phase I work which found methane gas at 4 - 5 feet below ground level in the vicinity of a few buildings in Onizuka Village housing, indoor air quality will be screened at select residences to confirm that no methane vapors are entering the homes. Readings are being taken in every room, under sinks, in closets, and in the garage area. To date, four residences have been screened and results indicate the air quality is normal. Note: The methane is present as a result of the natural breakdown of petroleum in the soil.
Mid-May - End-May 2013 –  Phase II work will include the boring of holes up to eight inches in diameter in front, back and side yards and common areas with a drill rig. Soil samples will be collected from the hole and a one inch diameter plastic pipe will be installed for groundwater samples. Then the bore holes will be refilled. Phase II work will begin on May 8 and is expected to continue through the end of the month.
Upon completion of Phase II, should any results be higher than Department of Health environmental action levels the Navy will initiate Phase III sampling efforts.
May 8, 2013 – Continuation notification letters were delivered to approximately 40 residents of Onizuka Village. The letter provided information on Phase II work that will be undertaken in the near future around their homes due to the Phase I soil gas results. Locations of interest are between Gemini Avenue and Freedom Avenue, and near Lewamawaho Loop and Opulepule Alley.
January - Mid-February 2013 – The first phase of sampling in Onizuka Village is scheduled to take place in January 2013, and should be completed within a few weeks. Work will include:
A survey of utility corridors (manholes, utility vaults and similar items).
The boring of holes two inches in diameter in front, back, and side yards and common areas with a drill rig. Limited access to backyards will be required. We will be collecting "soil gas" samples from these bore holes. "Soil gas" would be any gases rising from petroleum in the soil.
Residents will see vehicles and personnel conducting surveys and sampling, and work areas will be cordoned off with safety cones to prevent residents from potential trips and falls and injury associated with equipment being used.
Upon completion of Phase I sampling, any areas which have readings higher than State Department of Health environmental action levels will undergo a second phase or Phase II of investigation consisting of collecting soil, and groundwater sampling outside of residences to further define the nature and extent of impact.
January 2013 – Fact Sheets handed out to residents by contractor, door-to-door.
Jan. 15, 2013 – Open House from 5 p.m. - 8 p.m. at the Ka Makani Community Center. (No participants attended.)


This web page is a tool to address project specific information of the Environmental Study of Petroleum Stained Soil at Onizuka Village. Resident questions can be sent to NAVFAC Hawaii's Public Affairs Officer, Denise Emsley at Upon receipt of a question, it will be staffed by a subject matter expert and a response will be provided. Common questions and answers will be posted to this web page.
Questions & Answers
Q8. (July 30, 2013) What are the current findings and data for the subsurface soil gas survey, the groundwater sampling and indoor air readings of our building (Bldg. 5554)?
A8. Based on the data we've collected so far for the soil gas, soil, and groundwater, preliminary results compared with Hawaii Department of Health's screening criteria indicate there is no health risk due to the petroleum contamination. Results are as follows:

  •  Subsurface soil gas survey and utility corridor survey were performed over the entire Onizuka Village to determine where follow up sampling should be conducted. The utility corridors did not have any detections above background readings. Based on results of the subsurface soil gas survey, 7 locations including one location outside of Bldg. 5554 indicated that total petroleum hydrocarbons and methane in soil gas exceeded the Hawaii Department of Health screening criteria at 4 feet below ground surface.

  • Groundwater results at 20 locations were all below Dept of Health screening criteria. Four permanent monitoring wells were recently installed so we can continue to check the groundwater.

  • Soil results at 4 locations exceeded the Dept of Health screening criteria for total petroleum hydrocarbons. However, the soil in question is deeper than 4.5 feet below ground surface so residents are protected from exposure to the contaminated soil because of the "no dig" restriction.

  • Indoor air readings collected inside of 8 homes found no methane or other explosive gases inside any of the homes.

Q7. (July 30, 2013) What are the health risks for increased petroleum vapors? If the vapor levels exceed the Hawaii Department of Health screening criteria, then there are clearly health risks. When my neighbors have inquired about the health risks, we have been told there are not any. If it was just a precaution, then we would not be having to do a multiple step process that has taken several months to do. Considering current residents that are moving into these buildings are still not being notified of the current study, I believe we should know the possible health risks.
A7. Based on the data we've collected so far there is no health risk from the petroleum vapors found in the outside soil gas. It is important note that the screening criteria are conservative (safe) numbers that are based on exposure to chemicals over a 30-year duration. The criteria help us determine which locations need further investigation, and do not necessarily indicate a health risk. Since residents typically don't stay longer than one or two tours of duty, there should be no health risks from the petroleum contamination.
Since we know there is a soil gas exceedance outside of 7 buildings, the next step is to collect subslab soil gas samples beneath the buildings to see if any petroleum or methane vapors are accumulating beneath the buildings. This is what the contractor is currently doing by installing probes in each garage and coming back to sample. Preliminary results should be received in approximately one week. If petroleum or methane vapors are detected beneath the buildings we may return to the homes to collect indoor air samples and/or we may need to install equipment beneath each home to remove the vapors. Our course of action will be determined after all sample results are received, verified, and discussed with the Dept of Health Regulator.
The Navy intends to share the final results with Hickam Communities and residents at another Open House after all the results have been received and verified as correct. The process of checking the data typically takes the laboratory 30-45 days. We will also produce a report in a few months describing the investigation findings and our recommendations after all work has been completed, which will be provided to Hickam Communities and any residents who would like to receive an electronic copy.
Q6. (July 30, 2013) If possible, I would like to talk to an official at the Hawaii Department of Health who is working with you on this issue as well. It was stated that our health and safety is the military's top priority on this project (p. 2 of letter from Aaron Y. Poentis, sent July 11, 2013). If it was, we should be provided current data about the findings regardless if it is safe as well as new coming residents would be notified about the study being conducted.
A6. The Department of Health Regulator working with us on this study is Steven Mow, 586-7574. If you'd like to see any of the preliminary result tables and figures, please contact the NAVFAC project manager, Jocelyn Tamashiro, 471-1171 x362.
Q5. (May 9, 2013) When will the residents of Onizuka Village get to find out the results of all the soil and water testing that has taken place?
A5. Results of the soil gas, soil, and groundwater sampling will be shared with residents after NAVFAC Hawaii receives all analytical test results from the laboratory. This is expected to be mid-July. A meeting for the residents will be coordinated with Hickam Communities and at least two weeks' notice will be given to the residents so they can attend.
Q4. (May 9, 2013) Does the recent soil sampling have anything to do with carcinogenic pesticides? What is the soil testing for? Who is tracking the testing?
A4: The recent and ongoing testing in Onizuka Village is to determine where petroleum releases occurred, how much is present, and if cleanup is needed. No work with regard to pesticide soil is being performed. The Navy's sampling will determine whether carcinogenic chemicals associated with fuel are present and if they pose a risk. At this time, there is not enough data to verify the presence or absence of these chemicals or the degree of risk they might pose. NAVFAC Hawaii Environmental Restoration is managing the project.
Q3. (May 8, 2013) Would you please have any future meetings posted on the Hickam Communities Facebook page as well?
A3. If/when there is a general Onizuka Village resident meeting, I believe everyone will be personally contacted via letter again. Another possibility is that a meeting of all residents may not be necessary and only those that may be involved in Phase III of the remedial investigation may be invited to a meeting. Either way, I will try to provide an update on our web page when I have the information.
Q2. (May 8, 2013) Who was told about the Town Hall meeting in February and how was it advertised?  When will the next one be?  If there is not one currently scheduled, may we schedule one for July or August?
A2. All residents of Onizuka Village (approximately 300) received a letter inviting them to the January Open House to explain the remedial investigation project. The letter also provided information about the project. Currently, there is no meeting scheduled for May. As the website states, letters for Phase II of the project were hand-delivered on May 8, to residents living closest to upcoming work. This portion of the project will progress from May 8 until the end of May. Once results from Phase II are received, there will most likely be a meeting scheduled with residents. At this time I am not sure when. It depends on how quickly the work gets done and the results processed and analyzed so they can be shared.
Q1. (May 8, 2013) On Page 2 of the Onizuka Village Remedial Investigation Information link, no matter how large or small I make the page, I am not able to get a clear view of the Key, it is fuzzy.  Would you be able to tell me what the different things are?  There are orange triangles and some sort of orange or red dots, etc?
A1. You are correct the index is a little fuzzy. I had to go to a larger, original document, to see what you were describing. There are small filled red triangles (look like red dots) which are "proposed field screening locations." The large open triangles are "verification field screening locations." This chart was blown up at the Open House so that everything was clearer to view, including the index.

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