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Hi-Mill Manufacturing Superfund Site (Highland Township, Oakland County)
Web content may not routinely be updated on this page. Please contact the Site Lead for the most up-to-date status of the site.
Content posted August 2020.
EGLE Site Lead
Jason Harnick, HarnickJ1@Michigan.gov or 517-599-7421.
Hi-Mill Manufacturing Superfund Site located at 1704 Highland Road (M-59) is an active industrial site that encompasses 4.5 acres. Hi-Mill began manufacturing tubular aluminum, brass, copper tubing, and other parts in 1946. Highland Township, which is a suburb of Detroit, has a population of approximately 20,000 people. Approximately 3,700 of the residents are served by community water supplies, and the remainder use private wells for their drinking water.
The process wastewater from these operations was discharged to two, unlined lagoons until 1981 when a wastewater recycling system became operational and the company discontinued discharging to the lagoons. For a brief period of time afterwards, in an effort to dewater the lagoons, the Hi-Mill Manufacturing Company spray evaporated the water remaining in the lagoons into the air via roof-mounted sprayers. The lagoons were excavated, the sludge was disposed of, and the lagoons backfilled in November and December 1983. During the time they were in use, the lagoons often overflowed directly into the adjacent wetland in the Highland State Recreation Area and contaminated the wetland water and sediments
Contaminants of concern at the Hi-Mill Site are VOCs in groundwater. Because this is a Superfund site, EPA is the lead.
Groundwater flow slightly varies in each of the three aquifers present at the Hi-Mill Manufacturing site. These aquifers are essentially zones of water. Groundwater generally exhibits a radial flow in the shallow aquifer, to the southwest in the intermediate aquifer, and limited information suggests a southwesterly flow in the deep aquifer.
The closest receptor identified near the site is municipal drinking water, however the nearest municipal well is 3,000 feet away. These municipal wells were sampled in 2018 and there were no detections of PFAS. There are no residential wells near this site. There are several surface waterbodies near the site. These have not been fully evaluated but groundwater results near these locations show minimal impact.
- In September 2019, PFAS was sampled from select monitoring wells across the site. Two monitoring wells had detections of PFAS during the September 2019 sampling. Both monitoring wells had concentrations of PFOA above 8 ppt.
- In February 2020, damaged monitoring wells discovered during the September 2019 event were repaired.
- In May 2020, EPA/EGLE drafted a Groundwater Monitoring Plan for this site.
- In June 2020, EPA completed another round of groundwater sampling.
- EGLE is providing recommendations in the Fifth Five-Year Review for the inclusion of PFAS sampling into the site groundwater monitoring plan.
Residential Well Testing/Alternate Water Information
- No residential wells are located near the site.
Upcoming Community Engagement
- None scheduled at this time.
Sampling Results: PFOS and PFOA Only
Type of Sample
Date Sampled (or Range)
Number of Sample Results Received
Number of Samples Above PFOS Criteria
|Number of Samples Above PFOA Criteria|
- None at this time.