PUBLIC HEALTH ASSESSMENT
THERMO CHEM INCORPORATED
MUSKEGON, MUSKEGON COUNTY, MICHIGAN
The United States Environmental Protection Agency (U.S. EPA) listed the Thermo-Chem, Inc. site on the National Priorities List (NPL) on June 10, 1986. The site includes two properties owned by the Thomas Solvent Co.: the Thermo-Chem, Inc. property and the Thomas Solvent Co. property. The two properties combined cover approximately 9.5 acres of land located in Egelston Township, Muskegon County. The Thomas Solvent Co. operated on the site from 1961 to October 1986 as a licensed industrial waste hauler and reseller of reprocessed solvents. Thermo-Chem, Inc., a subsidiary of the Thomas Solvent Co., operated a solvent and chemical waste reprocessing, refining, and incineration facility on the site from 1969 until August 1980. During their operations, there were no physical barriers separating the properties.
Waste disposal practices, spills, and leaks during operations at the site resulted in extensive contamination of soil and groundwater at and near the site with volatile organic chemicals (VOCs), semi-volatile organic chemicals (SVOCs), and metals. The U.S. EPA investigations have determined that most of the contamination is located in operational and waste storage areas. Eighteen VOCs, 18 SVOCs, 16 inorganic compounds, 2 pesticides, and polychlorinated biphenyls (PCBs), have been identified as contaminants of concern for the Thermo-Chem, Inc. Superfund site (Table 1).
The site poses an indeterminate public health hazard under current conditions. The groundwater beneath and downgradient of the site is contaminated, but there is no indication that site-related contamination has reached private wells in the area. Trespassers may be exposed to contaminated surface soils via incidental ingestion and inhalation, however, data on surface soil are deficient. On-site surface soil sampling is needed to determine the extent of contamination of surface soils. In addition, further sampling of surface water and sediments in Black Creek near the site needs to be conducted to adequately characterize the extent of off-site contamination and to determine the entry point of contamination into the creek.
At the time of this writing, remedial clean-up activities and further characterization of off-site contamination are in progress. This assessment recommends that proper protective gear and measures be taken by remedial workers to reduce the likelihood of exposure. Access to the entire site should be restricted to prevent trespass by unauthorized individuals. Restrictions to prevent future use of the contaminated groundwater should be implemented.
The United States Environmental Protection Agency (U.S. EPA) listed the Thermo-Chem, Inc. site on the National Priorities List (NPL) on June 10, 1986 (1).
The Thermo-Chem, Inc. site is located on the south side of the road at 4331 Evanston Road, in Egelston Township, Muskegon County. It is in the NE 1/4 of the SW 1/4 of Section 31, Egelston Township (see Figure 1). The Thermo-Chem, Inc. Superfund site consists of two properties owned by the Thomas Solvent Co.: the Thomas Solvent Co. property and the Thermo-Chem, Inc. property. The Thomas Solvent Co. property is located at 4321 Evanston Road and covers approximately 1.5 acres in the northwest corner of the site (2). The Thermo-Chem, Inc. property occupies 8 acres south of the Thomas Solvent Co. property. The two properties combined cover approximately 9.5 acres. The Thomas Solvent Co. also owns a narrow strip (60' x 1,050') of land along the east property boundary of Thermo-Chem, Inc. (Figure 2). They used this strip for drum storage.
The Thomas Solvent Co. and its subsidiary, Thermo-Chem, Inc., operated an industrial waste hauling, reprocessing, and recovered solvent sale operation on the site from 1961 to October 1986. The Thomas Solvent Co. collected and transported the wastes and resold the recovered solvents. The Thomas Solvent Co. handled over 200 different chemicals in the Thermo-Chem, Inc. site facilities. Thermo-Chem, Inc., a subsidiary of the Thomas Solvent Co., operated a solvent and chemical waste reprocessing, refining, and incineration facility on the site from 1969 until August 1980. Thermo-Chem, Inc. distilled used solvents, paint wastes, and antifreeze to recover usable solvents. Unrecoverable materials and by-products such as sludge and residues were reportedly incinerated on the site. Wastewater generated during distillation and equipment cleaning was discharged into a series of three interconnected seepage pits (see Figure 2). The northernmost lagoon had a clay lining while the other two lagoons had no linings. The north lagoon received discharges of process wastes, discharges from inside the buildings, and runoff from storm drains outside the boiler building and in the reclaiming area. Cooling water was discharged to the middle seepage pit, and the south seepage pit received overflow from the middle seepage pit (2). An abandoned laboratory building, some former distilling operations structures, and some empty above-ground storage tanks remain on the Thermo-Chem, Inc. property. An office building, warehouse, and garage remain on the Thomas Solvent Co. property (3).
The Thomas Solvent Co. stored raw and recycled materials in sixteen underground storage tanks, with a total capacity of 104,000 gallons, on the site (4). During an inspection of the site in 1986, the Michigan Department of Natural Resources (MDNR) noted that these tanks appeared abandoned. At least 3,500 drums were stored on the Thermo-Chem, Inc. and Thomas Solvent Co. properties while the two companies were in operation (2).
During their periods of operation, there were no physical barriers separating the Thomas Solvent and Thermo-Chem properties, and operations and storage for each operation frequently overlapped onto the other's property. U.S. EPA and MDNR records indicate that the Thomas Solvent Co. and Thermo-Chem, Inc. had removed all contained hazardous wastes from the Thermo-Chem, Inc. property by late 1982. In 1988, investigators found an unknown quantity of various laboratory chemicals in the abandoned laboratory building on the Thomas Solvent property. U.S. EPA contractors removed the chemicals in the fall of 1988 (5).
On December 10, 1984, the MDNR conducted a soil gas survey and soil investigation at the Thermo-Chem, Inc. property. The study detected 1,1,1-trichloroethane (TCA), trichloroethylene (TCE), tetrachloroethylene (PCE), 4,4' DDT, 1,2-dichloroethylene, 1,2-dichloroethane (1,2-DCA), toluene, ethylbenzene, and xylenes in the soil and soil gas. On April 30, 1985, the MDNR conducted an investigation at the Thomas Solvent Co. portion of the site and found most of these contaminants in the soil. Samples of groundwater collected at the same time contained a similar set of compounds (5).
As a result of the findings from the soil analyses undertaken at the site, the MDNR contracted for a hydrogeologic study of the Thermo-Chem, Inc. site. The contractors installed four clusters of monitoring wells. Analyses of data from the borings identified two sand aquifers separated by a 7-foot-thick clay layer at the site. Groundwater samples from on-site contained low concentrations of volatile organic chemicals (VOCs) and off-site wells contained higher concentrations. The chemicals are assumed to have migrated from the Thermo-Chem, Inc. site (6).
The Thermo-Chem, Inc. site was proposed for inclusion on the U.S. EPA NPL in October 1984. The U.S. EPA placed the site on the NPL in June 1986. On April 30, 1987, a trucker, not related to operations at Thermo-Chem, Inc. or Thomas Solvent Co., spilled a quantity of 3,3'-dichlorobenzidine (DCB) at the site. The MDNR supervised the removal of the soils where the DCB had been spilled, and sampled the remaining surrounding soils. They found no detectable levels of DCB. The exact location of that spill is not in the available records (5).
The U.S. EPA and some of the Potentially Responsible Parties (PRPs) for the site signed an Administrative Order by Consent on September 21, 1987. Under the Consent Order, the PRPs agreed to conduct a Remedial Investigation and Feasibility Study (RI/FS) at the Thermo-Chem, Inc. property to determine the nature and extent of contamination problems at the property and to identify methods to correct these problems. The PRPs began investigative activities at the site in April 1989 (1, 2).
The Michigan Department of Public Health (MDPH), under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR), completed a Preliminary Health Assessment (PHA) for the Thermo-Chem, Inc. site on November 28, 1988. The PHA concluded that the site was of potential public health concern because of the possibility of exposure to chemicals of concern via contact with contaminated soil, surface water or groundwater. The PHA recommended restriction of access to the site and characterization of Black Creek to determine if the site had affected the water quality in the creek. The PHA did not recommend follow-up health activities at that time.
The site area is located in the Glacial Lake Plain physiographic unit. Surficial deposits in the area are primarily fine-to-medium grained lacustrine sand deposits, typically between 20 and 80 feet thick in the site area. A silty-clay unit, 100 to 150 feet thick, underlies the lacustrine sands. Bedrock beneath the Thermo-Chem, Inc. site is the Mississippian-aged Lower Marshall Sandstone. Bedrock units dip gently eastward, forming the western flank of the Michigan Basin (2).
The upper subsurface materials underlying the site consist of fine to medium sand, varying in thickness from 20 feet in the northeast to 55 feet in the southwest. The water table is approximately 17 to 22 feet below ground level. Two principal aquifers underlie the Thermo-Chem site. The thickness of the saturated zone within the upper unit ranges from 3 feet in the northeast to 33 feet in the southwest. A silty-clay layer, between 2 and 30 feet thick, separates the upper aquifer from a confined/semi-confined aquifer that varies in thickness from 61 feet to 116 feet. There is no evidence of direct hydraulic communication between the upper and lower aquifers. The direction of groundwater flow from the site is to the southwest towards Black Creek in the upper aquifer. However, in the lower aquifer, groundwater flow is to the south-southeast (2).
Black Creek flows to the west approximately 1,500 feet south of the site. Black Creek flows southwest to discharge into Mona Lake, approximately 5 miles southwest of the site. Mona Lake discharges into Lake Michigan, approximately 10 miles southwest of the site (2).
The northern two-thirds of the site was cleared and developed for Thermo-Chem operations and the remainder was left wooded. The ground surface of the site is relatively level. Surface elevation of the site is approximately 655 feet above mean sea level, with less than five feet of natural topographic change over the site. Significant artificial relief areas include constructed loading docks, three seepage pits which were approximately 10 to 15 feet deep, and a relatively small sand berm located at the southern border of the cleared area. A steep, sandy bluff drops approximately 35 feet from the site elevation to the north bank of the creek (2, 3).
The surface soil at the site is sandy, with a high infiltration rate for rainwater. Little surface drainage occurs on the site (5). Precipitation percolates directly through the unsaturated zone to recharge the unconfined aquifer below. No groundwater discharge areas are located on the Thermo-Chem, Inc. site. The only potential area of groundwater discharge occurs at Black Creek.
B. Actions Implemented During the Health Assessment Process
From April 1989 to December 1990, contractors for the Thermo-Chem PRPs conducted a Remedial Investigation (RI) of the site. The RI included an extensive soil gas investigation of the Thermo-Chem, Inc. site to map source areas of contamination in the unsaturated zone and the distribution of contamination within the groundwater beneath the Thermo-Chem, Inc. property (7).
From April 18 through 24, 1990, a U.S. EPA Region V contractor conducted a Technical Assistance (TA) investigation of the Thomas Solvent Co. property. The TA study included sampling of remaining underground storage tanks, a soil gas survey, collection of samples from soil borings, and a groundwater investigation (4).
From July 22 through 28, 1991, U.S. EPA contractors conducted an investigation of Operable Unit II (O.U. II) of the site, sampling surface water and stream sediment from Black Creek. The contractors reported their results in Technical Memorandum Number 3 to the RI/FS (8).
In September, 1991, the U.S. EPA signed a Declaration for the Record of Decision (ROD) for Operable Unit I (O.U. I) of the Thermo-Chem, Inc. site. O.U. I includes the remediation of contamination in soil, sludge and groundwater on-site and southward to Black Creek. The selected remedy includes decontamination, demolition, and off-site disposal of all on-site structures; excavation and off-site incineration of the most highly contaminated soils; in-situ vapor extraction for all remaining site soils; extraction and treatment of the groundwater with discharge to Black Creek; installation and maintenance of a fence around the site during remedial activities; and implementation of zoning and land use restrictions (9). Contractors for the PRPs, under U.S. EPA and Michigan Department of Environmental Quality (MDEQ)(1) oversight, have begun construction work for the Remedial Action (10).
Michael Lee of the MDPH and the project manager from the MDNR visited the Thermo-Chem, Inc. site on December 20, 1993. They drove through both the Thermo-Chem, Inc. and Thomas Solvent properties and observed the on-site structures. Lee also drove through the neighboring area during the site visit.
Lee observed that the Thermo-Chem, Inc. property was completely fenced, while the Thomas Solvent property has no restrictive barriers except the Thermo-Chem, Inc. fence. Other observations and information collected on the site visit are mentioned throughout this health assessment.
The area surrounding the site is semi-rural. Approximately 270 people live within 1 mile of the site. The 1990 Census reported the population of Muskegon County to be primarily non-Hispanic white, with 14% Black, 2% Hispanic, 0.8% Native American, 0.3% Asian or Pacific Islander, and 1% other races. Twenty-eight per cent of the County population was under 18 years of age, and 13% was 65 or older (3, 11).
Near the site area are residential areas, light manufacturing and commercial buildings, and wood lots. There is a house located adjacent to the Thermo-Chem, Inc. property on the west. MDNR personnel report that there are currently no residents in this house (3). Two mobile home parks are within 0.25 mile of the site, one to the west and one to the northwest. The mobile home park to the west was developed very recently and there are plans to expand the park further east toward the Thermo-Chem, Inc. site. A ready-mix concrete operation is located on the north side of Evanston Road across from the site, and a natural gas pumping station is located adjacent to the northeast corner of the site. The remainder of the bordering properties to the east, west, and south are undeveloped woodlands (2, 3).
Egelston and Sullivan (south of the site)(2) townships rely solely on groundwater as a drinking water source. The Fruitport Township (southwest of the site) municipal system supplies water to about 40% of its township residents, and the Muskegon Township (west of the site) municipal system supplies water to about 30% of the township residents. Both systems use water from Lake Michigan. Residences closest to the Thermo-Chem, Inc. site utilize water from private wells (2, 3).
The State of Michigan has designated Black Creek as a trout stream. In 1987, the MDNR applied rotenone to the creek to kill the resident fish population, and later restocked the creek with game fish species.
Two other Superfund sites are located near the site. The SCA Independent Landfill Superfund site is located approximately 300 feet south of Black Creek and 1,800 feet south of the site. The Bofors-Nobel Superfund site is located approximately 1.25 miles east of the site along Evanston Road (5).
The preparers of this Health Assessment obtained cancer incidence data from the MDPH Office of the State Registrar and Center for Health Statistics for the area around the Thermo-Chem, Inc. Superfund site.
No community health concerns have been received by the MDNR/MDEQ, the U.S. EPA, the local health department or the MDPH regarding the Thermo-Chem, Inc. Superfund Site. All of these agencies have been asked to refer to the MDPH any health concerns brought to their attention pertaining to the Thermo-Chem, Inc. site (12, 13, 14).
The Michigan Department of Public Health released a draft of this Public Health Assessment for public comment on January 31, 1996. The public comment period lasted until March 1, 1996. No comments were received in this period.