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K.I. Sawyer Air Force Base (Gwinn, Marquette County)
EGLE Site Lead: William Harmon, HarmonW@Michigan.gov. Content last updated November 6, 2020; map updated August 5, 2022.
K.I. Sawyer Air Force Base (KISAFB) is a former United States Air Force (USAF) base located near Gwinn. In 1994 after almost 40 years of operation, the KISAFB base closed under the United States federal government Base Realignment and Closure Act (BRAC). In 1999 Marquette County Airport, Sawyer International, occupying portions of the former base officially opened. Under BRAC the USAF is responsible for investigating and if necessary, addressing any environmental contamination caused by the Air Force while operating KIASB. For the past twenty years the USAF has been investigating and resolving environmental issues at the former base. Per- and polyfluoroalkyl substances (PFAS) are a group of over 5000 man-made chemicals that includes PFOA and PFOS. Firefighting foams used by the USAF contained PFOS and PFOA as active ingredients. In 2015 the Air Force identified 15 potential PFAS sites at the former KISAFB. In 2016 USAF conducted limited investigations of each site and detected PFAS at 13 of the 15 sites. USAF detected the highest concentration of PFAS at a former fire training area (FT007). The investigation and analysis of these PFAS sites by the Air Force is ongoing and will continue into the foreseeable future.
- Currently USAF is focusing its efforts on FT007. The USAF investigation or Site Inspection (SI) of FT007 consists of 3 Stages. Stage 1 of the SI focused on evaluating geology, groundwater flow, and the sampling of shallow groundwater around FT007 for PFAS. The objective of Stage 2 was to determine if PFAS was present in deeper groundwater. USAF completed Stage 1 December 2018 and Stage 2 in August 2019. The results from Stage 1 and Stage 2 SI indicate:
- Groundwater flows in an easterly direction from FT007
- A subsurface clay layer east of FT007 divides the groundwater into an upper and a lower aquifer
- PFAS contamination in the vicinity of FT007 is in the upper aquifer
- PFAS contamination downgradient of FT007 appears to be primarily in the lower aquifer
- October 2020 USAF completed Stage 3 of the SI for FT007. The objective of Stage 3 was to gain a better understanding of the subsurface geology, groundwater flow direction and the distribution and movement of PFAS in the groundwater. The Air Force conducted Stage 3 in two mobilizations. During Mob 1 the Air Force completed two exploratory borings along the eastern boundary of KIASB downgradient of FT007. In one boring the Air Force detected PFAS in the groundwater between 120 and 180 feet below the surface. In Mob 2 the Air Force completed 3 exploratory borings, installed, and sampled 3 temporary monitoring wells and measured groundwater elevations in 78 exiting wells and the three temporary monitoring wells.
- USAF identified and sampled 28 residential wells within a 4-mile radius downgradient from the FT007. Of the 28 wells sampled, one well was determined to have PFAS at levels above what is considered safe to drink. USAF installed a treatment system for this well and continues to test the drinking water. June 2020, USAF sampled the water after treatment. Lab results indicate there are no PFAS in the drinking water.
- On October 14, 2020 USAF held Restoration Advisory Board (RAB) and public meeting to update the RAB and the community on the latest results of the current SI, to brief community on USAF PFAS site prioritization process, KISAFB is ranked in the top 5 of USAF PFAS sites nationally, and to inform the community the Air Force will begin the Remedial Investigation (RI) at KISAFB Spring 2021. USAF follows the Federal Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) process to investigate and resolve sites of environmental contamination. The CERCLA process consists of several phases. The RI phase follows the SI in the process. The purpose of the KISAFB RI is to extensively investigate all PFAS sites identified by USAF during the SI.
- December 2020 - USAF will present all data collected during the SI in a comprehensive report.
- April or May 2021 - USAF will host a RAB/Public meeting to discuss the plan for the Remedial Investigation
- Spring 2021 - USAF will begin the RI of all PFAS sites at KISAFB
Residential Well Testing/Alternate Water Information
- To date USAF has tested 28 residential wells.
- USAF sampled 26 residences (27 samples total) from July – August 2019. EGLE received verbal results for all samples in September 2019.
- 26 samples were non-detect for PFOS+PFOA.
- These verbal results will be reflected in the Sampling table when results are confirmed in writing.
- Based on these results, two residences required additional sampling.
- At these two residences, USAF collected an additional 15 residential well samples.
- One residential well was sampled 4 times. All results including a duplicate sample were non-detect.
- The other residential well was sampled 11 times. The results from this well have been consistently above the Lifetime Health Advisory (LHA). USAF provided bottled water to the resident with sample results above the LHA; and later installed a whole-house resin-based filter system to treat the well water.
- The USAF maintains and samples the filter system for the resident.
- USAF last sampled the filter system September 2019.
- For additional information on residential well testing and results, visit the Frequently Asked Questions.
- EGLE has sampled all municipal water supplies for PFAS. The community of Gwinn purchases water from Forsyth Township. View the results for Forsyth Township.
Upcoming Community Engagement
- A RAB/public information meeting is planned by USAF for Spring 2021.
- On August 3, 2020, new Part 201 Criteria went into effect. Historical sampling data compared to Part 201 Criteria >70 is captured in the historical timeline below.
- Other PFAS analytes were detected in samples. There are no federal or state standards for these analytes.
- In April 2014, the former K.I. Sawyer Air Force Base site first came to the attention of the Michigan Department of Environment, Great Lakes, and Energy (EGLE) when the USAF’s contractor met with EGLE to conduct a record search to begin the USAF’s investigation into the base.
- In 2014-2015, the initial investigation (informally called “Phase I” by EGLE) was conducted by the USAF and included two fire training areas in the investigation area.
- From 2015-2016, hundreds of soil samples were taken, along with samples from the four on-base municipal water supply wells, groundwater, surface water, and at the Wastewater Treatment Plant (WWTP).
- In 2016-2017, the “Phase II” investigation by the USAF occurred and included other suspected locations of PFAS use, including three plane crash sites, fire suppression systems in a few buildings, storm water infiltration basins, two streams, three lakes, the WWTP, two landfills, and undeveloped areas where WWTP sludges were land-applied.
- In 2017, the USAF conducted sampling of surface water, sediment, the WWTP, and two residential wells east of the base. One of two residential wells had PFAS above the USEPA's Lifetime Health Advisory Level of 70 parts per trillion (ppt) PFOA and PFOS individually or combined; the other was non-detect. Bottled water was provided immediately by the USAF upon receipt of the first residential well samples, and follow-up samples collected from both residential wells had essentially identical results.
- In June 2018, the USAF installed a whole-house treatment system in a residence, and the treatment system is being operated by the USAF for the resident.Initial samples of the treated water were non-detect for all PFAS compounds (and they were consistent with concentrations in the well sample). The first routine quarterly samples of the system and the well were collected in early September 2018; (verbal) results show consistent contaminant levels in the well sample, and non-detect for the treated water.
- In November 2018, the USAF began a follow-up investigation of the extent of PFAS migration off-base (“Phase IV”). Six monitor wells (MWs) were installed, with an additional deeper MW at one of those locations planned once all recent sample data are available (note: the results have to date only been reported verbally). Additional locations were to be determined in 2019 based on all the new sample results, but the lack of detections caused the USAF to cancel the rest of the planned work and re-evaluate the plan.
- In December 2018, the USAF sampled the affected residential well; results were consistent with all previous samples.
- In December 2018, EGLE approved the final Site Inspection (SI) Report (“Phases I & II” work done on- and off-base from 2015 through 2017).
- In December 2018, the USAF submitted their Final Supplemental Site Inspection (SSI) Report (“Phase III” work done on- and off-base from February through June 2018).
- In January 2019, EGLE approved the Final SSI Report (“Phase III” work).
- In January 2019, EGLE provided an updated map for this site to use on the MPART webpage for the public.
- In March 2019, EGLE provided comments on the draft Site Investigation Workplan ("Phase IV") Revision 1 to the USAF.
- On March 14, the USAF's contractor sampled the well and the treatment system at the one affected residence. Results were consistent with all previous samples (with no detections of PFAS after treatment).
- On April 30, 2019, EGLE staff met with the USAF and contractors in Knoxville to finalize presentations to the AFCEC Administration for 2019 projects funding requests.
- On May 22, 2019, the USAF hosted an evening Public Information session. EGLE staff did not participate due to unexpected illness, however, MDHHS staff were in attendance, gave a presentation, and answered resident's questions.
- From July 17 – 20, 2019, the USAF and the USAF’s contractor sampled 26 residences downgradient of the single affected residence. A total of 27 samples (plus 3 field duplicates) were collected; two residences have treatment systems for high iron, and so samples were collected at each from before and after the treatment system. Samples also were collected from the one affected residence and the treatment system.
- From July 16 – 24, 2019, the USAF’s contractor installed a deep MW adjacent to a contaminated water table MW, after vertically profiling the aquifer (8 samples collected).
- In late July 2019, the USAF’s contractor sampled the well and the treatment system at the one affected residence. Verbal results are consistent with all previous samples.
- In early August 2019, the USAF’s contractor installed two additional shallow MWs in the residential well area, and two staff gauges in Silver Lead Creek to further refine the Conceptual Site Model.
- In late September 2019, EGLE met with the USAF and their contractor to review/approve locations for approximately 18 new MWs in the vicinity of the affected residential well, proposed to complete the site characterization (the exact number may change based on initial results).
- On October 16, 2019 the annual meeting of the Restoration Advisory Board (RAB) was held. This was not an EGLE or State hosted event. Ten interested citizens attended.
- On November 12, 2019. EGLE approved a USAF work plan for modifications to the residential well treatment system.
- On December 5, 2019 EGLE staff presented “Michigan Taking Action on PFAS” to the Michigan Tribal Environmental Group in Baraga.
- On December 11, 2019, EGLE staff presented a status update on UP PFAS sites to the four Upper Peninsula Tribes.
- In January 2020, EGLE staff met with USAF and their contractors to review their plans for 2020 field work, review/accept modifications to the residential well treatment system sampling schedule, and to transition EGLE project management due to the Site Lead’s retirement in February.
Related Sampling Notes
- Surface water and groundwater samples reflect both on-base and off-base activities.
- Soil, sediment, sanitary sewer influent, and groundwater treatment system effluent samples have been taken by the USAF at this site.
- The USAF sampled four municipal wells in 2015; PFOS was detected in one well at 1.36 ppt (not detected in a field duplicate from that well); all others were non-detect.
- Marquette County sampled the four municipal wells in 2016; all were non-detect.
Sampling : PFOS and PFOA Only
Type of Sample
Date Sampled (or Range)
Number of Samples
Number of Results Received
Number of Non-Detects Number Between Non-detect and Standard* Number Greater Than or Equal to Standard
Drinking Water (Residential Wells)
2017 - June 2020 42 16 5 0 11 Groundwater 2015 - June 2020 96 96 38 24 34 Surface Water 2015 - 2018 22 22 3 6 13 WWTP Effluent 2016 - 2017 2 2 0 0 2 Cumulative 162 136 46 30 60
*Groundwater results are compared to EGLE Part 201 Criteria of 70 ppt PFOS+PFOA.
*Residential well results are compared to the EPA Lifetime Health Advisory Level of 70 ppt PFOS+PFOA.
*Surface water results are compared to Rule 57 surface water quality values of 12 ppt PFOS and 12,000 ppt PFOA.