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New Cassel/Hicksville Groundwater Contamination Site
Nassau County, NY

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Cecilia Echols - (212) 637-3678

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Record of Decision [PDF 23 MB, 449 pp]

EPA listed the New Cassel/Hicksville Ground Water Contamination site on the National Priorities List (NPL) of sites eligible for long-term remedial action financed under the Comprehensive Environmental Response, Compensation, and Liability Act, more commonly known as Superfund, on September 16, 2011. The site is considered to be an area of widespread groundwater contamination within the Towns of North Hempstead, Hempstead and Oyster Bay in Nassau County, New York.

In 2010, EPA collected groundwater samples from raw (pre-treated) water from multiple public supply wells in central Nassau County and analyzed the raw water samples. EPA’s 2010 analytical results determined that there were volatile organic compounds (VOCs) above the Maximum Contaminant Level (MCL) in the raw water in four Town of Hempstead wells (Bowling Green 1 and 2, Roosevelt Field 10, and Levittown 2A), six Hamlet of Hicksville wells (4-2, 5-2, 5-3, 8-1, 8-3, and 9-3) and one Village of Westbury well (Water District 11). The MCL is a legal threshold limit on the amount of a substance that is allowed in public water systems under the Safe Drinking Water Act.  The public water suppliers monitor water quality regularly and based on past results have installed treatment systems to remove VOCs from groundwater.

The primary contaminants observed in groundwater at the site are tetrachloroethylene (PCE), trichloroethylene (TCE) and other VOCs. VOCs are contaminants that evaporate easily into the air and dissolve in water. They are often used as ingredients in paints, solvents, aerosol sprays, cleaners, disinfectants, automotive products and dry cleaning fluids.

EPA will be addressing the site in discrete phases or components known as operable units or OUs. An operable unit represents a portion of the site remedy that for technical or administrative purposes can be addressed separately to eliminate or mitigate a release, threat of release or exposure pathway resulting from site contamination. EPA anticipates that there will be multiple OUs for the site. 

The first phase of cleanup at the site addresses a portion of the contaminated groundwater downgradient of the New Cassel Industrial Area in North Hempstead and Hempstead.  Recently, EPA finalized its plan to clean up the contaminated groundwater as outlined in the September 2013 Record of Decision.  Other phases of cleanup at the site will include, but may not be limited to, the areas downgradient of the phase 1 cleanup, the Sylvania and the General Instruments sites in Hicksville, as well as areas impacting Hicksville public supply wells 4-2, 8-1, 8-3, 9-3 and Hempstead-Levittown 2A.


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