OSWER/OSRTI 

Washington, DC 20460 

NATIONAL PRIORITIES LIST (NPL) 

***Final Site*** September 2011 

NEW CASSEL/HICKSVILLE GROUND WATER New Cassel/Hicksville, New York 

CONTAMINATION 

Nassau County 

 S ite L oc ation: 

The site is located on Long Island, in the Towns of Hempstead, North Hempstead, and Oyster Bay, Nassau County. 

 S ite His tory: 

The site consists of contaminated ground water at and around industrial areas. In attempts to identify the source(s) of 

ground water contamination, New York State Department of Environmental Conservation (NYSDEC) conducted 

investigations in the area and indentified several possible sources. NYSDEC and individual potentially responsible parties 

(PRPs) have conducted remedial activities at several facilities. Despite these investigative and remedial efforts, NYSDEC 

has been unable to identify the specific source(s) of contamination in the public supply wells in the Town of Hempstead – 

Bowling Green and in Hicksville. In August 2010, EPA found contamination in many of these wells; some of which was 

above EPA’s Safe Drinking Water Act maximum contaminant levels (MCLs). 

 S ite C ontamination/C ontaminants : 

Since approximately 1988, sampling in the Bowling Green wells has found volatile organic compounds (VOCs), including 

trichloroethylene (TCE); tetrachloroethylene (PCE); and other volatile organic compounds (VOCs). More recent sampling 

has found PCE and TCE concentrations significantly exceeding the MCL. Contaminants in the Hicksville wells also 

include TCE, PCE, and other VOCs with concentrations exceeding the MCL. VOCs are commonly used in commercial and 

industrial operations such as dry cleaning and metal degreasing. 

 P otential Impac ts on S urrounding C ommunity/E nvironment: 

The Bowling Green wells serve a combined population of more than 8,000 people. In Hicksville, the wells serve a 

combined population of more than 24,000 people. The water department treats the extracted ground water to remove VOCs 

prior to distribution. The contaminated wells withdraw water from the Magothy aquifer, the primary source of drinking 

water in Nassau County. There are numerous other public supply wells that tap the Magothy aquifer within 4 miles of the 

site. 

 R es pons e A c tivities (to date): 

The Towns have installed treatment systems to remove VOCs from the contaminated ground water prior to distribution, 

and monitor the water quality and treatment system effectiveness regularly. EPA and the state have investigated numerous 

possible sources of contamination, though the exact source(s) of the contamination has not been determined. 

 Need for NP L L is ting: 

The State of New York referred this site to EPA because of contaminated drinking water in the Hicksville area. Other 

federal and state cleanup programs were evaluated, but are not viable at this time. EPA received a letter from the state 

supporting listing of the site on the NPL. 

[The description of the site (release) is based on information available at the time the site was evaluated with the HRS. The description may change 

as additional information is gathered on the sources and extent of contamination.] 

For more information about the hazardous substances identified in this narrative summary, including general information regarding the effects of exposure to these 

substances on human health, please see the Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs. ATSDR ToxFAQs can be found on the Internet 

at http://www.atsdr.cdc.gov/toxfaq.html or by telephone at 1-888-42-ATSDR or 1-888-422-8737.