The West 45th Street site is located on the west side of mid-town Manhattan. The main site features include a large package sorting facility on operable unit (OU) 1 and a parking lot on OU-2. OU-2 is on a separate block from OU-1. The surrounding parcels are a highy urbanized combination of commercial, industrial, and residential uses. DNAPL and other wastes associated with the MGP operations have been found on OU-1 and OU-2. The remedial investigation for OU-1 is ongoing to determine the full extent of contamination. The investigation phase on OU-2 is completed and the remedy planning phase is currently on-hold, awaiting devleopment plans from the property owner.
Site Environmental Assessment
Historically, the chemicals of concern at a manufactured gas plant (MGP) are benzene, toluene, ethylbenzene, xylene (BTEX) and polycyclic aromatic hydrocarbons (PAHs). BTEX and PAHs have been found in the soil and groundwater at the site in exceedance of standards, criteria, and guidance. This site presents a possible significant threat to the environment because of the possibility of contaminants of concern being released from source areas into the groundwater. The primary contaminants of concern on the OU-2 portion are BTEX and PAHs. Investigations indicate a plume of contaminated groundwater under the site and subsurface soil contamination due to the release of dense nonaqueous phase liquid (DNAPL) under the site. Exceedances of standards, criteria, and guidance include BTEX and PAHs in groundwater and soils under the site. The Hudson River is roughly 50 yards from the site on the west and may be impacted. The site presents a signicant threat due to the ongoing releases of contaminants from source areas into groundwater.
Site Health Assessment
Manufactured Gas Plant waste has been identified in surface, subsurface and groundwater at the site. Currently, a paved parking lot associated with the USS Intrepid museum occupies the site. There is a potential for exposure to low level site-related contamination in surface soils through direct contact in areas that are not paved or covered by buildings. Exposure to site-related contaminants in groundwater is not likely since homes and businesses near the site are connected to public water. The results of sub-slab vapor and indoor air samples collected from on-site buildings do not indicate a public health concern. NYSDOH and NYSDEC are conducting further investigations to determine the potential for soil vapor intrusion into structures on and near the site.