RACER Buick City (Flint, Genesee County)

• April 2018, the first PFAS sampling was conducted by RACER Trust under a USEPA-approved workplan. The USEPA simultaneously collected and analyzed their own samples. Samples were collected on-site from eight groundwater monitoring wells in an area thought to be a former firefighting training area where AFFF is believed to have been used. Three analytical methods were used to analyze the samples, all of which were generally in agreement.
  • Combined PFOA+PFOS were above 70 ppt in three monitoring wells.
• May 31, 2018, additional groundwater samples were taken from five monitoring wells, both on and off-site, to gain further information on the source of PFAS in the area and the extent of the contamination.
• July 19, 2018, RACER updated EGLE, MDHHS, USEPA, city of Flint, Genesee County Parks and Health Department in Flint at the county office.  RACER presented the second round of PFAS sampling results from the Fire Training area and plans to sample groundwater in five additional areas.
• August 3, 2018, RACER submitted work plans to EGLE and USEPA for sampling groundwater for PFAS at 5 additional areas on the Buick City site.
• August 7 and 16, 2018, RACER met with the USEPA and EGLE to discuss the work plans for sampling the proposed five additional areas.
• August 13, 2018, the city of Flint conducted sampling in three sanitary sewer tributary lines that flow to the East Pump Station, one of which drains from the Buick City area.  Two of these had PFOS levels below 12 ppt, while the third one, which drains from Buick City, had PFOS levels of 720 ppt.
• August 23, 2018, RACER updated EGLE and USEPA on the history of storm water investigations and the potential of storm water reaching the Flint River. 
• August 28, 2018, RACER sampled groundwater near the former firefighting area, former Wastewater Treatment Plant (WWTP), and the former plating and painting line.
• September 27, 2018, RACER collaborated with the city of Flint to sample five sanitary sewers on and near Buick City site.
• October 9, 2018, RACER briefed EGLE and USEPA on the PFAS found in groundwater samples collected August 28, 2018.  PFAS was found associated with the firefighting training area at levels up to 600 ppt total tested PFAS. Total tested PFAS was found associated with historic painting operations at 15,000 ppt.  Samples collected near a storm water conveyance in the areas of the former GM WWTP were 4,800 ppt total tested PFAS in groundwater, and two groundwater samples collected near the former painting/enameling operation area were 4,600 ppt and 4,800 ppt total tested PFAS, respectively.
• October 15, 16, 17, 2018, RACER collected groundwater, storm sewer and sanitary sewer samples.
• October 16, 2018, RACER and EGLE met with Genesee County Health Department to provide an update on the most recent PFAS findings and the Drinking Water well survey near Buick City.  The well survey did not identify any drinking water wells on the Buick City property or near the property. GM conducted the first survey in 2000 as part of the site risk assessment reported to USEPA; RACER updated the survey of drinking water wells in 2011 and again in 2018.  EGLE conducted a field verification of the survey in 2018.
• October 24, 2018, RACER and EGLE met with the city of Flint to provide an update on sample results and plans for additional sample collection.  RACER re-affirmed that drinking water well surveys support that no Flint residents are drinking groundwater. RACER also shared that PFAS discovery at Buick City had created uncertainty in remedial plans, therefore, redevelopment of the Buick City property is paused to allow RACER to characterize and understand PFAS.
• October 31, 2018, RACER shared sanitary sewer sample results collected September 27, 2018, with the USEPA and EGLE. The results ranged from less than 0.5 ppt to 860 ppt PFOS in the sanitary sewer.
• November 7, 2018, RACER updated the city of Flint, Genesee County Health Department, EGLE, MDHHS, and USEPA with the results of sampling in October and proposed additional sampling of groundwater and storm water.  Five storm water samples were collected ranging from below 10 ppt to 4,000 ppt PFOS. One sanitary sewer sample result was 130 ppt PFOS.  Of the 22 groundwater samples, PFOS results were:
  • 2,510 ppt and 6,070 ppt near the pickling and enameling area
  • 10,090 ppt near the paint shop
  • As high as 18,660 ppt east of the railroad tracks in an unknown source area
  • As high as 38,000 ppt near the former paint shop
  • 10 locations had PFOS over 1,000 ppt
• November 13, 2018, RACER presented the draft communication plans and fact sheet to USEPA, EGLE, city of Flint and Genesee County Health Department for the Buick City Site titled "Cleanup Progress at Former Factory Complex" intended for distribution at the meetings held on November 14 and 15, 2018. 
• November 14, 2018, RACER held a public meeting in Flint   at 6 p.m. at Harding Mott University Center -- Kiva Room, University of Michigan-Flint Campus, 400 Mill Street.
• November 15, 2018, RACER held a public meeting at 6 p.m. at Metropolitan Baptist Tabernacle, 930 E. Myrtle Avenue (at Industrial Avenue).
• December 18, 2018, RACER submitted a memo to EPA and EGLE regarding outfall sampling at outfalls 003 and 005. The memo described PFAS sampling of groundwater from 14 site monitoring wells, storm water samples from 10 locations within the Outfall Drainage Area 003 storm sewer system, and storm water from four locations within the Outfall Drainage Area 005 storm sewer system.  PFOS was detected in the groundwater and storm water, requiring further evaluation of the site conditions.
• December 20, 2018, RACER updated EGLE, USEPA and the city of Flint on the data in the December 18, 2018 memo.

• January 11, 2019, RACER met with EGLE to present the findings in Outfalls 003 and 005.  RACER discussed preliminary plans to conduct additional PFAS sampling of storm water and groundwater.  Plans for sampling will be presented to EGLE on January 25.
• January 25, 2019, RACER presented plans to EGLE regarding next steps to investigate  Area 010, Area 011, improve delineation in vicinity of RFI-44-05 - (building 44), Area 008 - (factory 84) focus on groundwater movement to river, and in Area 003 - delineate groundwater impacts in the vicinity of old WWTP.
• January 30, 2019, RACER submitted a summary of the Sanitary Sewer Sampling results to the EGLE. The sample collected from the sanitary sewer in the right-of-way of Hamilton Avenue contained PFOA at a concentration of 2,280 ppt and PFOS at a concentration of 27,580 ppt. The next downstream sample collected from the sanitary sewer, contained PFOA at a concentration of 420 ppt and PFOS at a concentration of 4,670 ppt.  Additional investigation of the sanitary sewer is warranted.
• February 13, 2019, Genesee County Health Department hosted a meeting at their offices in Flint.  City of Flint, EGLE, RACER, DHHS and others were in attendance to receive updates regarding Coldwater Road Landfill, Gilkey Creek, Richfield Landfill, Buick City, Bishop Airport, and Flint River fish advisory.
• February 14, 2019, RACER submitted a summary of Outfall 008 to EGLE. EGLE is reviewing the summary, RACER concluded in the summary that although PFAS has been detected in groundwater near and along the conveyance in the Outfall Drainage Area 008, there does not currently appear to be a complete pathway for groundwater to enter the storm sewer conveyance and reach the Flint River. 
• February 19, 2019, RACER met with EGLE to discuss outfall investigations.
• February 22, 2019, RACER submitted a summary of sampling activities and evaluations completed as part of the required short-term characterization study for per- and poly-fluoroalkyl substances (PFAS) at the Outfalls associated with the Buick City Site.  
• February 26, 2019, RACER, EGLE and EPA met in Chicago to update EPA on investigative work testing the sanitary sewers, storm sewers, groundwater and soil on and near the former Buick City site during the federal government shutdown.
• March 8, 2019, EGLE, DHHS, RACER, City of Flint and Genesee County Health Department participated in a PFAS Town Hall at the Mott Foundation in Flint.  This event was hosted by several area legislators to share "PFAS 101" and all PFAS sites in the Genesee County/ City of Flint.
• March 13, 2019, EGLE issued a violation notice to RACER Trust for Buick City regarding Storm water - outfall samples that exceeded water quality standards.  The letter requested that RACER conduct sampling of all outfalls associated with the Buick City site during both dry and wet weather conditions by July 1, 2019.  RACER agreed to follow through with the request.
• March 14, 2019, RACER Trust, EGLE, EPA, DHHS, Genesee County Health Department and City of Flint held a public information meeting at the Metropolitan Baptist Tabernacle, located at 930 E. Myrtle Avenue in Flint to provide the community with an update on RACER's environmental activities at Buick City.  The update included the most recent test results for PFAS.
• March 29, 2019, RACER, EGLE, City of Flint and Genesee County participated on a panel at the Resiliency Week 2019: Friday Morning Environmental Justice Session.  The panel shared an update of PFAS results in Genesee County and the City of Flint.  The focus of the discussion was Buick City.
• April 3, 2019, RACER collecting samples to evaluate PFAS in soil.  Results are expected to be reported out in April.
• April 9, 2019, EGLE received a letter from RACER which outlined plans to reuse soils from the I-475 MDOT project at Buick City.
• April 10, 2019, EGLE received Outfall Drainage Areas 005, 010, and 011 From RACER.
• April 15, 2019, EGLE received PFAS results for the Outfall Drainage Areas 005, 010, and 011. Eight storm water samples were collected from outfall 05, the concentrations of PFOA range from 8 to 13 ppt and PFOS range from 42 to 50 ppt in samples collected from manholes along Outfall Drainage Area 005 storm sewer. The two samples collected from the french drain, prior to being discharged to the Outfall Drainage Area 005 storm sewer, detected PFOA at concentrations ranging from 19 to 24 ppt and PFOS at concentrations ranging from 180 to 230 ppt. The sample collected from Outfall 005 at the river detected PFOA at a concentration of 13 ppt and PFOS at a concentration of 45 ppt.
• April 16, 2019, RACER Trust led a bus tour of the Buick City site.
• May 7, 2019, EGLE received Outfall 001 and 006 PFAS sample results
• May 16, 2019, EGLE received a report from RACER that summarizes the usefulness of available soil and leaching data, including PFAS, in determining the acceptability of soils for reuse at several locations along Highway I-475 in Flint near the RACER Buick City property. Soils containing concentrations above applicable EGLE criteria cannot be accepted without special accommodations.
• May 17, 2019, RACER supplied engineering drawings for a storm sewer (outfall 003) re-route to the City of Flint.
• May 20, 2019, EGLE received a work plan to assess dewatering efforts required to install the storm sewer reroute. 
• June 11, 2019, EGLE received a report on PFAS investigation at Outfall 001, 005A and 006.
• June 13, 2019, EGLE, RACER, ARCADIS, EPA and MDOT met to discuss the I-475 project and relocation of excess soil. 
• June 14, 2019, EGLE, RACER, ARCADIS, County Health Department, City of Flint, and DHHS met to for a county wide update on PFAS activities, including Buick City.
• July 8, 2019, EGLE, RACER, ARCADIS, MDOT met to discuss excess soil reuse and sampling.
• July 15, 2019, EGLE received from RACER the second report on the Short -term characterization study and revised work plan.  Reporting out dry and wet weather sampling completed to date.  Sampling is proceeding as weather conditions allow.
• July 19, 2019, EGLE approved the RACER workplan to test excess soil in the I-475 project.
• August 8, 2019, EGLE collected soil samples at I-475, EGLE reviewed and compared the results to the generic residential cleanup criteria as provided in Part 201.  The results did not exceed generic criteria.
• August 9, 2019, EGLE received storm sewer sampling result.
• August 13, 2019, RACER hosted a bus tour and public meeting at the Metropolitan Baptist Tabernacle.
• August 19, 2019, EGLE collected soil samples at I-475, EGLE reviewed and compared the results to the generic residential cleanup criteria as provided in Part 201.  The results did not exceed generic criteria.
• August 20, 2019, Excess soil from MDOT I475 project started to be delivered to Buick City.
• August 22, 2019, EGLE collected soil samples at I-475, EGLE reviewed and compared the results to the generic residential cleanup criteria as provided in Part 201.  The results did not exceed generic criteria.
• August 28, 2019, EGLE collected soil samples at I-475, EGLE reviewed and compared the results to the generic residential cleanup criteria as provided in Part 201.  The results did not exceed generic criteria.
• September 10, 2019, EGLE sent a letter to RACER regarding compliance with the NPDES permit.
• September 30, 2019, EGLE received results of additional PFAS sampling conducted in July and August 2019 at the RACER Buick City site.
• October 24, 2019, EGLE, RACER, and EPA met to discuss PFAS.
• November 5, 2019, EGLE received draft Corrective Action Plan pursuant to the Michigan Department of Environment, Great Lakes and Energy (EGLE) September 10, 2019 letter requiring the submittal of a CAP for the Buick City Site (the Site) by November 7, 2019 to address surface water quality standards. November 11, 2019, EGLE received the final storm water 003 Re-Route plan from RACER.
• November 21, 2019, EGLE attended the RACER storm water re-route of outfall 003 Contractor Bid Meeting with the city of Flint.
• December 2019, EGLE received storm water sampling data.  The sampling results are reflected on the sampling chart.  EGLE also received a soil sample report for I-475 soils placed on the site.

• January 23, 2020, RACER collected PFAS-impacted groundwater sample (at over 20,000 ppt of PFAS), to provide to the University of Michigan for bench scale testing to assess the potential of a plasma based PFAS destruction technology.
• February 6, 2020, EGLE and RACER met to discuss the storm water data results.
• February 7, 2020, EGLE received sanitary line summary.
• February 13, 2020, EGLE sent enforcement letter to RACER in order to offer an Administrative Consent Order.
• March 3, 2020, EGLE and RACER met to discuss the voluntary Administrative Consent Order to meet compliance with PFAS discharging to the Flint River.
• March 4, 2020, RACER announced work to replace and reroute over 3,600 feet of underground storm sewer lines (Outfall 003) through RACER Trust's Buick City property began the first week of March 2020 and is expected to take approximately four months to complete.

  Type of Sample	Date Sampled	# of Samples	# of Results Received	# of Non-detects	# Between Non-detect and standard*	#>Standard
  Type of Sample	Date Sampled	# of Samples	# of Results Received	# of Non-detects	# Between Non-detect and standard*	#>Standard
  Groundwater	Apr 2018 - July 2020	176	176	27	28	121
  Storm Water	Dec 2018 - July 2020	176	176	24	46	106
  Sanitary Sewer	Jan 2019 - July 2020	24	24	5	7	12
  Cumulative		376	376	56	81	239

  *Groundwater results are compared to EGLE Part 201 Criteria of 70 ppt PFOS+PFOA.
  *Surface water samples are compared to Rule 57 non-drinking water values of 12 ppt for PFOS and 12,000 ppt for PFOA.

  • March 12, 2020 EGLE and RACER held meetings to discuss the Corrective Action Consent Order between EGLE and RACER, PFAS issues are significant.
• March 27, 2020, RACER notified EGLE that pursuant to Executive Order 2020-21 issued on March 23, 2020 site work will be limited to inspection and maintenance.  The rerouting of a storm sewer line (outfall 003) through Buick City to stop PFAS discharges was started in March however was delayed due to Covid-19 Executive Order. 
• May 4, 2020, RACER developed a COVID-19 Continuity Plan for Buick City.  The plan provides guidance for all work, including PFAS sampling.
• May 7, 2020, RACER resumed construction activities on the rerouting of a storm sewer line (outfall 003) through Buick City and sampling activities in accordance with the Michigan Safe Start plan. 
• May 20, 2020, RACER and EGLE held a virtual meeting to discuss PFAS Sampling locations and reported results available to date of the phased investigation of a PFAS source area at the south end portion of the former General Motors Buick City site which included the Building 44 area near Hamilton Avenue.  
• June 4, 2020, RACER and EGLE held a virtual meeting to discuss a groundwater monitoring well network and PFAS sampling planning due to the high PFAS levels identified in soil and groundwater.  The highest PFOS result reported in groundwater was 3,400,000 ppt; highest PFBS was 140,000 ppt; highest PFHxA was 59,000 ppt; highest PFNA was 200 ppt; and the highest PFOA was 54,000 ppt.  High levels, up to 11,000,000 ppt of PFOS, were also identified in soils.   Additional PFAS sampling results were also reported for the north end.  Soil and groundwater investigation for PFAS as well as other site related contaminants, including lead, at the Buick City site is ongoing and more detailed summaries from RACER, including maps and figures, can be found at EGLE's Buick City web site.
• June 15, 2020, RACER installed plugs in three select laterals connected to Outfall 010 to prevent PFAS from reaching the Flint River.
• June 18, 2020, RACER provided EGLE with the Buick City Outfall 010 and 013 bulkheading and plugging work plan to address PFAS.
• Week of June 22, 2020, RACER installed a bulkhead at Outfall 013 to eliminate the contribution from a lateral entering the main at manhole MH 13-11.
• Week of July 6, 2020, RACER collected water samples from the Outfall 013 storm sewer to assess PFAS impacts following bulkheading activities.
• July 14, 2020, RACER provided EGLE with an update on PFAS investigation around Outfalls 010, 011, 013.
  • Dye Testing and PFAS testing with the City of Flint to assess a sanitary sewer along Hamilton Avenue.
  • Outfall 003 Reroute is progressing
  • Outfall 010 has sampling scheduled for July and August to evaluate the plugging efforts.
  • RACER submitted a work plan to the City of Flint to plug three laterals connected to Outfall 011 storm sewer.
  • Samples of sediments and stormwater were collected from outfall 002 stormwater line downgradient of the previously installed bulkhead to assess the condition of 002 before the reroute is completed and active.  Elevated levels of PFAS were found in both storm water and sediment, but not in adjoining groundwater samples.
• July 24, 2020, RACER reported to EGLE progress in identifying two likely source areas for PFAS - one near the Stewart Avenue overpass, the other just north of Hamilton Avenue.
  • Five soil samples just north of Hamilton Avenue contained PFAS at concentrations greater than 100,000 ppt, with the highest single sample at 660,000 ppt.
  • RACER and EGLE are reviewing historical records to identify manufacturing activities that may have resulted in such high readings.
  • RACER and EGLE are discussion further investigation and determine the best way to address these soils.
  • PFAS also was found in groundwater just north of Hamilton Avenue at concentrations as high as 46,000 ppt.
  • PFAS was found in a storm sewer pipe near the Stewart Avenue overpass in excess of 20,000 ppt.
• On July 27, 2020, RACER began the second round of delineation to identify where PFAS contaminated groundwater may be leaking into storm and sanitary sewers (and eventually discharge to the Flint River).  Identification and delineation of this source area is a positive step in the ongoing corrective action and redevelopment process.  RACER's groundwater sampling crews and drilling rigs were mobilized to collect more soil and groundwater samples near Hamilton Avenue.
• August 5, 2020, RACER and EGLE sign Corrective Action Consent Order and EPA terminated its order with RACER.
• August 7, 2020, RACER proposed groundwater and sample locations for leach testing of PFAS in soil
• September 17, 2020, RACER and EGLE had virtual meeting to discuss the drilling and sampling completed from June to August 2020.
• September 21, 2020, RACER proposed additional drilling locations along Hamilton to EGLE.
• September 28, 2020, RACER provided EGLE with the following update below.  In addition to groundwater and storm water samples, RACER tested 124 soil samples and 17 sediment samples.
  • Michigan established a Maximum Contaminant Level of 51 ppt for PFHxS, it has been included in the data to evaluate the relationship between PFOS and PFHxS.
  • Groundwater samples were collected from eight monitoring wells north of Stewart Avenue, six of the wells detected PFOS at concentrations exceeding the GSI criterion of 12 nanograms per liter (ppt). The maximum detected concentration of PFOS was 100 ppt; however, PFOS concentrations in the most downgradient wells sampled did not exceed GSI criteria.
  • At the Former Firefighting Training Area (FTA) (south of Stewart Avenue) two soil borings were completed and temporary wells were installed at each location. Groundwater samples were collected from the temporary wells and one existing monitoring well to further evaluate impacts in the vicinity of RFI-10-26 (location being further delineated), where the highest concentration of PFOS in groundwater has been detected. These borings complete the upgradient delineation of the FTA. Additional investigation is not planned in this area.
  • At the location of the former Wastewater Treatment Plant (WWTP) (near Stewart Avenue and Selby) one soil boring was completed to further evaluate impacts in the vicinity of monitoring well 55-4. PFOS was not detected in either of the soil samples collected. This boring completes the delineation of the WWTP area. Additional investigation is not planned in this area.
  • In the vicinity of the Former Painting Area (FPA) (north of Lieth Street) four soil borings were completed and temporary wells were installed at each location. Groundwater samples were collected from the temporary wells and five existing monitoring wells to further evaluate impacts in the vicinity of RFI-81-09. PFOS was detected in soil at 200 ppt in. The delineation groundwater samples detected a high of 110 ppt upgradient of RFI-81-09 and 66 ppt downgradient. Additional investigation is not planned in this area, at this time.
  • At the Building 12 Area (near and south of Leith Street) additional investigation activities were completed to further delineate impacts identified at RFI-12-27 and RFI-12-34 . Three soil borings were completed and temporary wells were installed at each location. Groundwater samples were collected from the temporary wells and 10 existing monitoring wells. Soil samples detected PFOS at 2,900 ppt. The delineation groundwater samples detected a high of 1,100 ppt downgradient of RFI-12-27. Impacts at RFI-12-34 are delineated. Further investigation is planned at RFI-12-27.
  • Investigation activities were completed in the Building 16 Area (south of Building 12 area) to further delineate impacts identified at RFI-16-25. Two soil borings were completed and temporary wells were installed at each location. Groundwater samples were collected from each temporary well and four existing monitoring wells. Soil samples detected PFOS at 2,300 ppt. The groundwater samples detected PFOS at 11,000 ppt upgradient of RFI-16-25.  Additional work is being planned.
  • At the Building 84 Area (near Hamilton Avenue and James P Cole) additional investigation activities were completed to further delineate impacts identified at RFI-84-07S. Nine soil borings were completed and temporary wells were installed at eight of the locations. Groundwater samples were collected from the temporary wells and 13 existing monitoring wells. Soil samples detected PFOS at 88,000 ppt. The delineation groundwater samples detected 110,000 ppt upgradient of RFI-84-07S. Additional delineation work was completed in this area.  
  • The Building 44 Area has been divided into three areas (Bldg 44 East, Bldg 44 Central, and Bldg 44 West) to make it easier to see the sample locations and read the data boxes  in the figures. The reported results include 30 borings, 106 soil samples and 62 groundwater samples. Soil samples detected PFOS at concentrations as high as 11,000,000 ppt at boring SB-04-64. The groundwater samples detected PFOS at a concentration of 3,400,000 ppt at SB-04-47. PFOA was detected in groundwater at 54,000 ppt in the Building 44 Area. In addition, 11 soil samples were submitted for leaching using three methods. The results from the leaching tests and related analysis will be reported in October. Additional delineation work is planned to be completed at the Bldg 44 Area.
  • Outfall 001 - sampling to date has not shown a PFAS contribution from Buick City.  Confirmatory sampling is planned for this fall or spring.
  • Outfall 002 - was resampled just downstream from this reconnection in July and no PFAS was detected at the closest location. Once the reroute is completed this fall this section will be resampled to confirm the earlier findings of PFAS to the Outfall 002 storm sewer.
  • Outfall 003 - most of the new storm sewer has been installed; however, the work has been temporarily delayed. The re-route is expected to significantly reduce if not effectively eliminate the site's PFAS and Oil contribution to the Outfall 003 storm sewer. Resampling will be conducted in early spring to confirm the performance of the reroute.
  • Outfall 004 - This storm sewer was bulkheaded at the CSX railroad tracks, which effectively eliminated the base flow component. The remaining active portion of Outfall 004 is above the water table, and subsequently Outfall 004 was dry during the dry weather sampling event. The wet weather sample detected PFOS at a concentration of 1.8 ppt.
  • Outfall 004A - Outfall 004A was dry during the dry weather sampling event. The wet weather sample detected PFOS at a concentration of 46 ppt. A second wet weather sample will be collected when the discharge point is accessible - it is currently submerged and cannot be sampled during wet weather events.
  • Outfall 005 - A flow study designed to quantify the flow of groundwater entering the Outfall 005 storm sewer is scheduled this fall. That information will be used to assess remedial alternatives.
  • Outfall 005A - Outfall 005A was dry during the dry weather sampling event. The wet weather sample did not detect PFOS; however, PFOA was detected at a concentration of 0.86 ppt. No further investigation is planned at Outfall 005A.
  • Outfall 006 - PFOS was detected at Outfall 006 in the dry weather sample at a concentration of 96 ppt and in the wet weather samples at concentrations of 11 ppt and 106 ppt. The data are currently being evaluated.
  • Outfall 007, 007A, and 008- Outfalls 007, 007A and 008 are likely above the water table as no flow was observed during a dry weather sampling event. The discharge locations for 007, 007A, and 008 are currently submerged and as such cannot be sampled during wet weather events. Outfalls 007 and 008 were bulkheaded at upgradient manholes MH 7-1 and MH 8-1, respectively. There are currently no accessible points to sample these outfalls during a wet weather event.
  • Outfall 012 - Outfall 012 is likely above the water table as no flow was observed during a dry weather sampling event. The discharge location for 012 is currently submerged and as such cannot be sampled during wet weather events. The last downgradient manhole at the Site is unable to be located and upgradient manholes are dry. There are currently no accessible points to sample this outfall during a wet weather event.
  • Outfall 010, 011, 013 - laterals in the Outfall 010 (five), 011 (two), and 013 (one) storm sewers were bulkheaded in 2020 to eliminate known sources of PFAS from RACER property contributing to PFAS concentrations in these storm sewers. Following bulkheading activities, the Outfall 010 and 013 storm sewers were sampled at a location downgradient of the bulkheads to evaluate their effectiveness. Samples collected from Outfalls 010 and 013 exhibit exceedances of the Rule 57 surface water criterion of 12 ppt for PFOS. Options for further actions to address these exceedances are currently being considered. Additional sampling at Outfall 010, 011, and 013 is planned to be completed in October.
  • October 22, 2020, RACER hosted an information meeting with USEPA, EGLE, and the City of Flint, to discuss PFAS investigations, community engagement, and general status of environmental activities.

• October 28, 2020, Work on the Outfall 003 Reroute resumed.
• November 23, 2020, RACER completed a video of the Outfall 010 storm sewer to identify potential sources of infiltration, discharge, or collapse to assess PFAS.
• December 2020, By the end of December, RACER installed both new main sewer lines. Investigation of PFAS continues including evaluation of PFAS soil and groundwater impacts and evaluation of remedies to address PFAS in sewers. samples were collected from Outfall 010, Outfall 011, the sanitary sewer and
• daylighted groundwater to investigate the daylighting incident.

• January 19, 2021, EGLE held a conference call with RACER to discuss updates on daylighting of groundwater near Hamilton Avenue.
• February 11, 2021, a video was completed of northwestern storm sewer lateral entering Outfall 010.
• March 18, 2021, water and sediment samples were collected from the eastern former aeration lagoon for analysis of VOCs, SVOCs, metals, PCBs and PFAS.
• March 2021, 18 manhole structures in the Building 04 Area were filled with concrete to minimize PFAS flow to the storm and sanitary sewers in Hamilton Avenue.  After the completion of filling activities samples were collected from select manholes along the Outfall 010 and Outfall 011 storm sewers and the Hamilton Avenue sanitary sewer to evaluate PFAS concentrations.
• April 2021, PFAS soil and groundwater delineation investigation continued at the Former Foam Generation Building in the Northend of the Site and Building 04, Building 16, and Factory 84 Areas in the Southend of the Site.
• April to June 2021, RACER performed groundwater investigations for groundwater chemistry parameters to evaluate for future remedies from.
• April 1, 2021 through September 30, 2021, Site work include completing 110 soil borings and collecting approximately 310 soil samples and 133 groundwater samples.
• May 2021, storm sewer manhole MH 10-5 was filled with concrete to eliminate PFAS impacted groundwater infiltration into the structure.
• May 5, 2021, an incremental sampling (IS) investigation was completed at the soil/sediment stockpile on the western aeration lagoon to characterize the pile for PFAS.
• May 6, 2021, temporary plugs were installed in the sanitary storm sewer at manholes MH H-1 and MH H-1A.
• May 26 and 27, 2021, six test pits were completed in the Building 04 area to collect soil samples for bench scale testing of PFAS Treatment technologies.
• June 8-9, 2021, an investigation was completed in the eastern aeration lagoon to collect and analyze surface water samples and soil for PFAS.
• July 12 through July 14, 2021, a hydraulic profiling tool (HPT)/vertical aquifer profiling (VAP) investigation was completed east of the former aeration lagoons to characterize groundwater flow and potential PFAS impacts in groundwater.
• July 16, 2021, a temporary plug was installed at storm sewer manhole MH 11-6 to block PFAS flow coming from the former Outfall 009 storm sewer reaching the river.
• August 2021, to better understand groundwater migration and fate and transport of PFAS monitoring wells were installed in Hamilton Avenue and south of Hamilton Avenue.
• August 10 through 12, 2021, fourteen manhole structures near Hamilton Avenue were filled with concrete to minimize flow of water contaminated with PFAS in Site storm and sanitary sewer laterals connected to the storm and sanitary sewers in Hamilton Avenue.
• August 27, September 1, and September 2, 2021. Five manhole structures in the Hamilton Avenue Area were filled with bentonite and concrete.
• August 31 through September 2, 2021 a geophysics survey was completed in the Hamilton Avenue area of the Site to provide additional characterization of potential historical subsurface building foundations and other obstructions which may affect remedy selection/implementation.
• September 13, 2021, temporary plugs were installed in two laterals along the Outfall 011 storm sewer to eliminate PFAS impacted discharges to the sewer from those laterals.
• September 14, 2021, bulkheads were installed along Outfall 010 at manholes MH10-4 and MH 10-2 to eliminate the Site's contribution of PFAS to Outfall 010 from those two manholes.
• In addition to the specific Site activities noted above, various Site investigation activities were completed as listed below:
  • PFAS soil and groundwater delineation investigation continued at the Former GM Foam Generation Building and Former Aeration Lagoons in the Northend of the Site and Building 04, Building 12, and Building 16, and Factory 84 Areas in the Southend of the Site.
  •  Soil samples were collected from the Building 04 Area to delineate benzo(a)pyrene impacts.
  • Soil samples were collected from the Power Plant area and field south of the former aeration lagoons to characterize the area.
  •  Samples were collected from select manholes along storm sewer Outfall 002 and 003 for PFAS analysis to evaluate the post Outfall 003 re-route conditions.
  • Wet weather samples were collected from the Outfall 004, 004A, 007, 007A, 008 and 012 outfalls for PFAS analysis to complete the short-term water characterization study required by EGLE.
  • Additional PFAS investigation samples were collected from storm sewer Outfalls 002, 003, 004, 005, 010, 011, and 012 and the sanitary sewer in Hamilton Avenue.

Sampling Results Summary

*Residential well and groundwater monitoring well results are compared to EGLE Part 201 criteria for 7 PFAS compounds:  PFOS (16 ppt), PFOA (8 ppt), PFNA (6 ppt), PFHxS (51 ppt), PFHxA (400,000 ppt), PFBS (420 ppt), and HFPO-DA (370 ppt).

Sampling Notes

• 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.
• August 5, 2020, EGLE entered a Corrective Action Consent Order with RACER and EPA rescinded its order, making EGLE the lead regular overseeing the corrective action, including PFAS oversight.
• Other PFAS analytes were detected in samples. There are no federal or state standards for these analytes.
• A nanogram per liter (ppt) reported by a laboratory is the same as a part per trillion (ppt).

• February 3, 2022, RACER submitted an Additional Lagoon Investigation Work Plan, which proposed additional PFAS sampling and hydraulic conductivity testing at the Eastern Lagoon Area.
• March 16, 2022, RACER submitted a Tracer Injection Test Work Plan. The work plan involved injecting a dye tracer at the south end of the site, near Hamilton Avenue, to help understand groundwater flow in this area and the migration of PFAS contamination.
• April 6, 2022, EGLE approved the Tracer Injection Test Work Plan.
• May 4, 2022, RACER submitted Workplan for Removal of Water from Former East Lagoon and Stabilization of Sediments for the treatment of PFAS at East Lagoon Area, located north of Leith Street.

• February 3, 2023, RACER submitted a progress report on the Tracer Injection Test occurring at the south end of the site, near Hamilton Avenue.  
• April 18, 2023, EGLE received an Infiltration Management and Generic LNAPL and PFAS Soil Management Plan detailing how areas of PFAS contamination would be handled with the upcoming redevelopment at the site. 
• August 24, 2023, EGLE received a Pilot Study Work Plan for the treatment of PFAS at the site. The Work Plan proposed to test the use of in-situ chemical oxidation to destroy PFAS at a small area on-site. The Work Plan could not be approved because the process involved injecting a substance into the ground that would be considered a hazardous waste once its use in the treatment process was completed.
• October 18, 2023, EGLE met with RACER to discuss the status of the PFAS investigation at the south end of the site, north of Hamilton Avenue.
• November 17, 2023, EGLE, U.S. EPA, and RACER met to discuss available technologies for the treatment of PFAS and considerations for treatment at the site.
• December 13, 2023, EGLE met with RACER to discuss the development of site-specific soil criteria for PFAS. Development of soil criteria will help in determining remedial goals for the site.