Marquette County, Gwinn, K.I. Sawyer Air Force Base

Updated: March 19, 2020

KI Sawyer Groundwater Investigation MapBackground

K.I. Sawyer Air Force Base is a former United States Air Force (USAF) base located near Gwinn. The base operated for nearly 40 years and closed in 1995. Marquette County Airport currently occupies a portion of the base.

Recent Accomplishments

  • 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.

Next Steps

  • Awaiting the written results of recent residential well and new monitor wells (MWs) sampling.
  • Approximately eighteen new MWs will be installed in the vicinity of the affected residential well in spring 2020.  The sample results from vertical profiling of the first 4 MWs will be used to guide screen depths at the remaining 14 locations.

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 public information meeting is planned by USAF for Spring 2020.
Sampling: PFOS and PFOA Only

Type of Sample

Date Sampled

Number of Samples

Number of Results Received

Number of Non-detects

Number of Detections Below Standard*

Number of Detections Greater Than Standard*

Drinking Water (Residential Wells) 2017-2019 41 15 4 0 11


2015-2018 84 84 32 22 30
Surface Water 2015-2018 22 22 3 6 13
WWTP Effluent 2016-2017 2 2 0 0 2
149 123 39 28 56

*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.

Sampling notes

  • Other PFAS analytes were detected in samples. There are no federal or state standards for these analytes.
  • 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.

Historical Timeline

  • 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.