The Mohonk Road Industrial Plant, which was designated an EPA Superfund Site in 1999 due to a high level of soil and groundwater pollution, has been reclassified, from a Class 2 State Superfund Site to a Class 4. This means that the state Department of Environmental Conservation (DEC) has concluded that, after roughly 24 years of cleanup efforts, the site “no longer presents a significant threat to public health and/or the environment.”

The site will continue to be monitored periodically for changes in status of the soil and groundwater.

According to the DEC, the Mohonk Road Industrial Plant lies off Mohonk Road in the vicinity of the High Falls Water District.

Background

The roughly 14-acre property has a long history of being used by industries known to use harmful solvents and other chemicals, which, apparently, were often dumped into a septic system on the property.

From the early 1960s to 1972, a metal finishing company called Varifab, Inc., owned and occupied the site. According to the EPA, the company used solvents in the finishing and assembly of metal parts for card punch machines and computer frames. Then from 1972 to 1975, a wet spray painting company, R.C. Ballard Corp., operated there; the EPA suspects the company of using “large quantities of solvents in order to clean surfaces prior to painting.” After that, in 1976, Daniel E. Gelles Associates, Inc., used the site to manufacture store display fixtures, which the EPA said “may have involved the use of solvents.”

Eventually, the years of alleged dumping made its way into the local water system. In April 1994, a resident contacted the Ulster County Health Department (UCHD) questioning the quality of her drinking water. When the UCHD sampled the resident's well, they discovered levels of volatile organic compounds (VOCs) above state and federal drinking water standards. Primary “contaminants of concern” found in the samples included vinyl chloride, 1,1-dichloroethane, 1,4-dioxane, 1,1,1-Trichloroethane (TCA), and trichloroethene (TCE).

While soil contamination was limited to the site property, the DEC noted that the contamination of the groundwater was found to extend off-site to the north for about 1 mile.

After further investigation, the EPA placed the property on the Superfund program’s National Priorities List (NPL) in January 1999. And in May 2000, cleanup efforts, including groundwater extraction and treatment, began. The EPA removed about 2,567 tons of contaminated soil and waste from the site. The DEC also worked with the EPA to provide and maintain “granular activated carbon” (GAC) filtration units for 75 area homes and businesses to make sure they had access to clean water.

In the fall of 2007, the EPA finished the construction of a drinking water treatment plant and distribution system to serve the affected water district. With the new water treatment plant in place, those 75 homes and businesses no longer needed the filtration units, and could hook up to the new system, the EPA explained. After that, the EPA continued to monitor the area around the contamination site, as well as the groundwater.

In 2011 and 2019, respectively, the EPA transferred the maintenance and monitoring of the site’s two “operable units,” or cleanup areas, to the DEC. The first “operable unit” included the treatment plant and other containment systems. The second operable unit comprised the groundwater that was being monitored.

This month, the DEC announced, “Remedial actions have been completed at the [Mohonk Road Industrial Plant] site which include the excavation of contaminated soil, use of a soil vapor extraction system, use of a groundwater pump and treat system for the near-field groundwater plume and development of a new water district to provide an alternate water source to residences and businesses in the impacted area. Soil vapor mitigation is also installed in the on-site commercial building. The site is subject to institutional controls that prevent the use of groundwater as a drinking water source and require continued operation of the on-site soil vapor extraction systems. There is a groundwater monitoring program in place to evaluate the effectiveness of the remedy.”

While the reclassification points to a successful reduction of contaminates in the surrounding soil and groundwater, the site has not received a “Certificate of Completion,” which is what happens when a site reaches Class 5. The EPA will also continue to prepare five-year reviews of the location on a regular basis.

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