The Hoskins Manufacturing Mio plant, which operated from the late 1960s to 2001, manufactured thermoelectric nickel and chromium alloys in the form of wire, strip and ribbon. The contamination was caused by poor waste handling and chemical storage practices including numerous overflows from waste holding tanks, discharges of waste to unlined trenches, improper storage of waste in deteriorating drums outside and spills and overfills from acid and solvent storage tanks. In 1976, a private water well located 800 feet from the facility was found to be contaminated with chlorides and total chromium. As a result of this discovery, Hoskins Manufacturing was listed as a site of contamination.

In 1995, during routine monitoring of the groundwater flowing beneath the property, Hoskins Manufacturing discovered tetrachloroethylene (common solvent also called PCE) in the groundwater. Limited investigations conducted by Hoskins revealed the presence of PCE and chromium in the soil and groundwater at the site. PCE was detected in the groundwater at the site at concentrations 400 times greater than the PCE concentration that is considered safe to drink. Extensive areas of soil contamination were found on the property, including a former solvent tank area, the outdoor drum storage area and the former lagoon area. In March 2002, Hoskins Manufacturing abandoned the plant leaving behind over 700,000 gallons of chemicals and waste materials in various containers. In 2002, at the request of the DNRE, the U.S. Environmental Protection Agency (EPA) removed all the containers containing chemicals and waste that were left behind and fenced a portion of the site.

The DNRE investigated the extent and severity of the contamination in the soil, groundwater, stream sediment and surface water (Perry Creek) between 2003 and 2009. The DNRE is currently monitoring the contamination in the groundwater and implementing a cleanup action on portion of the groundwater contamination in 2010 and 2011.

SOIL 

The investigations reveal multiple areas of soil contamination on the Hoskins property surrounding the former building location. Several of these areas had deposits of waste sludge contaminated with heavy metals at less than one foot below ground level. Chromium was detected in the sludge at levels 15 times greater than the chromium concentration that is considered safe for dermal (skin) contact. In May 2006, the EPA removed approximately 9,500 tons of contaminated material from the site. The source areas the EPA addressed included all known areas of waste sludge and the resulting highly contaminated soil. Additional contaminated soil was removed after the building was demolished in 2008. Contaminated soil remains at the former Hoskins Manufacturing property above the drinking water and groundwater to surface water protection criteria.

BUILDING

In 2006, the EPA cleaned the interior of the on-site buildings to facilitate demolition. The equipment and scrap metal were cleaned and placed outside the building for disposal, the free dust was vacuumed, interior surfaces pressure washed, and all hazardous debris, sludge and wastewater were disposed of from the building. An asbestos survey was completed inside the former Hoskins Manufacturing buildings in June 2007 to identify asbestos containing building materials to be removed prior to demolition. Also in 2006, the EPA installed a security fence around the entire building and access drive to the site to prevent unauthorized access.

The demolition, including the removal and disposal of the former Hoskins Manufacturing buildings and all aboveground structures, floors, underground vaults and water wells, was completed in January 2008 by the DNRE. After the main building floor was removed, the highly contaminated soil/sludge beneath the former pickling line was excavated for disposal. Approximately 7,300 tons of demolition debris and non-hazardous contaminated soil and 1,300 tons of hazardous soil were removed from the site. In May 2008, after the snow had melted, the site was leveled and seeded and the remaining debris removed. The site currently appears as a grassy field with little evidence that an industrial facility existed there. The fence surrounding the location of the former buildings will remain to provide security for future investigation and cleanup activity at the site.

GROUNDWATER

The primary contaminants detected in the groundwater are PCE, hexavalent chromium and chlorides. The groundwater contamination extends horizontally from the Hoskins main plant building southeast to Perry Creek which is approximately one-half (1/2) mile long. This area of groundwater contamination is known to be generally 500 to 550 feet wide. A portion of the groundwater contamination plume discharges to Perry Creek and a portion goes beneath and beyond (east of) Perry Creek. The upper unconfined aquifer has been found to be most impacted by the groundwater contamination with some contamination detected in a leaky confined aquifer located on the southern portion of the site. No contamination has been found to date in the nearby eleven residential drinking water wells that are sampled annually; however, the groundwater contamination plume appears to be migrating slowly towards a residential neighborhood to the south of the site.

PERRY CREEK

Perry Creek is a designated trout stream and a tributary of the Au Sable River, which is a Blue Ribbon Trout Stream and designated Scenic River under the Federal Wild and Scenic Rivers Act. PCE and chromium have been detected in surface water samples in Perry Creek as far as 1/2 mile south of where the groundwater contamination enters the creek. In only one sampling event in 2005 has hexavalent chromium been detected in Perry Creek above levels that are injurious to aquatic organisms from long-term exposure. At all other sampling events, contamination levels detected in Perry Creek were below concentrations known to be both chronically and acutely toxic to aquatic organisms.

Sediment sampling in Perry Creek was conducted in 2007 and 2008 to determine if the creek sediment has been impacted by the discharging contamination plume and to determine the chronic toxicity of the sediments to aquatic organisms. A macroinvertebrate study was conducted in Perry Creek also in June 2007 to determine if the aquatic community has been impacted by the discharging groundwater contamination. Results from the sediment sampling and macroinvertebrate study indicate that the discharging contamination plume is impacting the known plume discharge area for both the sediment chemistry and aquatic organism health, but conditions rebound within 1/2 mile downstream.