Delphi Plants 400 and 500 (Flint, Genesee County)

Delphi Plants 400 and 500 are located at 2926 Davison Road, Flint, Michigan. Plant 400 was first developed in the early 1900s, and Plant 500 was developed in the late 1950s. Both plants were owned by General Motors Corporation (GM) and were part of the Flint East Manufacturing Complex. GM divested the plants in 1999 and they became part of Delphi Corporation. In 2005, Delphi Corporation declared bankruptcy and announced plans to close the Flint East Manufacturing Complex. Manufacturing at the complex ended in early 2006; the Plant 400 buildings and the above ground structures were demolished in 2008; and the Plant 500 buildings and above ground structures were demolished in 2009. The current owner is Delphi Property Holdings Trust (DPH).

The automotive products manufactured at Plant 400 included spark plugs, dashboard components, fuel system components, filter components, and fuel pumps; this manufacturing used a variety of lubricating oils, degreasing solvents, paints, and fuels. Plant 500 was used for automotive engineering research, which included administrative office space, laboratories, and engine test cells.

In 2017, EGLE Water Resources Division sampled Gilkey Creek (approximately 800 feet south of the site) and found elevated levels of PFOS. Subsequent to this initial sampling, EGLE initiated an investigation to determine the sources of PFOS to the creek and identified the site as one of multiple potential sources. On July 27, 2018, EGLE and site consultant Tetra Tech Consulting & Remediation, Inc. (Tetra Tech), sampled groundwater from the wells for PFAS. PFOS was detected at 10 ppt, and PFOA was detected at 15 ppt, both below the criteria applicable at the time.

In 2018, the City of Flint collected a grab sample from the effluent of the site's groundwater treatment system, as part of Michigan's Industrial Pretreatment Program, to evaluate potential sources of PFAS to the wastewater treatment plant. Several compounds were present, with PFOA (15 ppt) in excess of the groundwater clean-up criteria that went in effect in 2020.

In 2021, DPH investigated PFAS and sampled 29 monitoring wells at the site, as requested by EGLE and the United States Environmental Protection Agency (U.S. EPA). PFAS compounds were detected in 24 of the 29 monitoring wells sampled. Results across the site ranged from non-detect to over 29,000 ppt total PFAS at one well. (Note that the next-highest well is 634 ppt total PFAS).

The site is led by the U.S. EPA, under the federal Resource Conservation and Recovery Act of 1976, as amended (RCRA). RCRA Corrective Action is being implemented per the DPH Environmental Response Trust bankruptcy settlement agreement. EGLE is providing support for RCRA Corrective Action activities at this site.

Gilkey Creek is located approximately 800 feet due south of the site. Groundwater flow is variable across the site, but in southern sections it flows in a southwesterly direction. Additional data will be collected to determine whether the site is a significant source of PFAS to Gilkey Creek.

Content posted August 2022.

The area is served by municipal water. EGLE is working with Department of Health and Human Services (DHHS) to determine if there are any residential wells currently in use that are downgradient of this site, to determine if any homes need to be sampled.

To prevent off-site impacts determined necessary by the storm water investigation, the U.S. EPA and EGLE will require DPH to implement additional delineation and remedial measures, as necessary.