Syosset Landfill

Overview

The Syosset Landfill is a 38-acre former municipal landfill in Oyster Bay, New York. It accepted commercial, industrial, residential, demolition, agricultural, sludge, and ash wastes from 1933 to 1975. EPA added it to the National Priorities List (NPL) in 1983, and cleanup activities began in 1986. EPA deleted the site from the NPL in April 2005 after determining all appropriate cleanup actions had been completed.

The site contains 18 identified contaminants of concern in soil, groundwater, and air. Volatile organic compounds (VOCs) include benzene, toluene, trichloroethene, tetrachloroethene, vinyl chloride, and chloroform. Heavy metals and metalloids found include arsenic, barium, selenium, and zinc. Other organic compounds detected include 1,1-dichloroethene, chlorobenzene, dichloromethane, and dibutyl phthalate. An investigation in 1992 and 1993 found that contamination migration was limited and posed no significant threat, so groundwater remediation was not required.

Cleanup actions addressed the landfill itself and off-site groundwater as two separate operable units. For the landfill, workers installed a permanent ventilation trench to stop gas from migrating toward a nearby school, capped the landfill in November 1997 to contain roughly 6.7 million tons of contaminated material, and put in place a gas collection system with ongoing air and groundwater monitoring. A 1996 Record of Decision for the off-site groundwater operable unit determined no further action was needed there. Institutional controls restrict future land use to make sure the remedy stays effective.

Human exposure to contamination is under control. There are no unacceptable exposure pathways as long as site use restrictions and institutional controls remain in place. The Town of Oyster Bay redeveloped the property for municipal use, including a salt storage facility, equipment storage, vehicle parking, and a compressed natural gas fueling station completed in 2011. As of December 2024, four on-site businesses operated at the site, employing 61 people and generating about $122,600 in annual sales.

EPA completed its most recent five-year review in December 2021, confirming the cleanup continues to protect human health and the environment. The next review is scheduled for December 2026. Community members can review site records at the EPA Records Center at 290 Broadway, 18th floor, in New York City, or at the Syosset Public Library at 225 South Oyster Bay Road in Syosset. For questions, contact the EPA site team directly using the information below.