M-60 Tanker Spill (Howard Township, Cass County)

• On April 7, 2016, the gasoline tanker spill occurred and EGLE responded. Initially, soil and groundwater sampling and analyses focused only on volatile organic compounds (VOCs); none were detected. Residential well water samples were collected from two nearby residences to the north and east and analyses detected no VOCs.
• On September 14, 2017, Brenner Oil collected a groundwater sample from the source area monitoring well and had it analyzed for PFOS and PFOA at EGLE request. Results were 16,000 ppt PFOS and 13,000 ppt PFOA. Brenner Oil determined that local groundwater flows to the northeast, toward a creek and Mud Lake.  Brenner Oil asserted they were not liable for PFOS and PFOA in the groundwater, as this was applied by the Howard Township Fire Department.
• On January 18, 2018, EGLE collected a PFAS confirmation sample from the source area monitor well. The result was 382,000 ppt PFOS; 12,800 ppt PFOA. EGLE also collected water samples from two nearby residences for analysis.  PFAS was not detected in the down-gradient residential water sample, and trace amounts of PFOS was detected in the cross-gradient residential water sample.
• On April 5, 2018, EGLE requested that Brenner Oil as a responsible party determine the extent of PFOS and PFOA contamination in the groundwater and monitor area water supply wells under the authority of Part 201. 
• On April 25, 2018, EGLE collected quarterly PFAS samples from the same two residential water supply wells near the site, and one additional upgradient residential well.  PFOA was detected at trace levels in all the residential water supply samples.
• On May 21, 2018, Brenner Oil agreed to monitor groundwater and residential water supply wells for PFOS and PFOA.
• In June 2018, Brenner Oil installed additional downgradient monitor wells.
• On July 10 and 11, 2018 Brenner Oil sampled the source area monitor well; two downgradient monitor wells north of M-60, and two residential water supply wells for PFOS and PFOA.
• On August 27, 2018, EGLE received laboratory results that said there was no PFOS or PFOA detected in the two residential water supply wells. However, maximums of 1,700 ppt PFOA and 10,400 ppt total tested PFAS were detected in the two downgradient groundwater monitoring wells north of M-60, indicating that these contaminants had migrated downgradient and across the highway. Testing at the source area monitor well detected 40,000 ppt PFOA and 1,280,000 ppt PFOS.
• On September 6, 2018, Brenner Oil installed and sampled 3 additional downgradient monitoring wells to determine the extent of volatile organic gasoline contamination.
• On November 7, 2018, EGLE received a report from Brenner Oil and laboratory testing confirming gasoline contamination had already reached this downgradient groundwater monitoring well locations.  Laboratory analyses at these downgradient locations did not include PFOS or PFOA.
• On November 30, 2018, Brenner Oil requested permission from the property owner to install additional monitor wells and collect the next round of groundwater samples for laboratory analyses.
• In 2018, EGLE requested information regarding remedial approaches the liable party intends to use to mitigate and prevent the migration of contamination off-site and to Mud Lake.

• On January 16, 2019, the property owner presented his alterations to the proposed access agreement to Brenner Oil's insurance carrier for consideration.
• On February 14, 2019, Brenner Oil's insurance carrier returned an updated access agreement proposal to the property owner for consideration and the property owner agreed to allow access in late April.
• Consultants for the liable party contacted the property owner regarding proposed drilling locations and to plan to begin fieldwork on May 1. The insurance company made arrangement with the property owner for site access in late April 2019.
• On April 22, 2019, EGLE received an update on the status of this access agreement and access had been obtained and work would commence as soon as weather permitted.
• The liable party installed staff gauges along the un-named creek and two downgradient monitor wells of three originally planned.  They also conducted another groundwater sampling event on June 6-7. Six (6) monitor wells and 2 residential water supply wells were tested for PFOA and PFAS.  Results were received by EGLE on August 22, 2019.   Monitor well 17D, which was dry in June and July was sampled in August for gasoline components. 
• In November 2019, EGLE received a report indicating gasoline components were not detected in the furthest downgradient monitor wells in 2019.  Based on these results, consultants cancelled plans to install one additional downgradient monitoring well.  Consultants are evaluating the groundwater flow direction to determine potential surface water discharge locations.
• On December 6, 2019 the consultant of the liable party completed the re-testing of monitor and residential water supply wells; results were received in a report on March 5, 2020.  The liable party tested water samples for petroleum compounds only.  The report determined that contaminated groundwater flows beneath an unnamed creek east of the site and requests EGLE concurrence with a proposal to install additional downgradient monitor wells to define the extent of contamination.

• On June 18-19, 2020, the liable party sampled 10 monitor wells for petroleum compounds and two residential water supply wells for PFAS compounds in addition to petroleum compounds.  
• On August 5, 2020, EGLE received the results of the re-testing of monitor and residential water supply wells that occurred in June 2020. The liable party tested 10 monitor wells for petroleum compounds, 2 of which were sampled for PFAS analysis.  Two residential water supply wells were also sampled for PFAS compounds in addition to petroleum compounds. 
• On December 4, 2020, the liable party installed two downgradient monitoring wells. 

• On January 25, 2021, EGLE received the laboratory analyses results of the groundwater samples from those two monitor wells.  Merit Laboratories reporting limits for these PFAS compounds varied from 9.5 to 10 ppt, exceeding the Part 201 Cleanup Criteria for some of the regulated PFAS compounds.
• On April 13, 2021, EGLE received a "Deep Groundwater Investigation Report" summarizing the results of fieldwork completed in late 2020.  The report proposes additional groundwater monitoring in 2021 but does not mention testing residential water supply wells in the area or testing many of the existing monitor wells in the area for PFAS/PFOS.

*Groundwater results are compared to EGLE Part 201 Criteria of 70 ppt.
*Residential well results are compared to the USEPA Lifetime Health Advisory Level of 70 ppt PFOS+PFOA.

Sampling Results Summary

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.
• Other PFAS analytes were detected in samples. There are no federal or state standards for these analytes.
• There are other contaminants in the groundwater associated with this release.