Emergency Response for Sub-Slab Depressurization System and Groundwater Remediation

Project:    Cropsey Avenue
Location:    Brooklyn, New York
Services:    NYSDEC Spill Investigation, NYSDEC Spill Remediation, SSDS System

Hydro Tech was contacted when strong odors associated with gasoline vapors were detected in the basement of the new development prior to the building being occupied. The site was associated with an open NYSDEC Spill number which was supposedly rectified by others during site development.

The New York State Department of Health (NYSDOH) through the New York State Department of Environmental Conservation (NYSDEC) issued an order not to occupy the building so Hydro Tech had to work fast to get the problem fixed. We coordinated with all agencies to install a SSD system beneath each of the seven 3-story vacant residential buildings to prevent soil vapor intrusion beneath the site and mitigate indoor air impacts.

The SSDS was monitored on a quarterly basis. The SSDS successfully prevented the sub-slab gasoline vapors from impacting the indoor air, which was revealed to contain petroleum- related compounds close to the background concentrations. Upon verifying this conclusion, the NYSDEC in consultation with NYSDOH and NYCDOH authorized the occupation of the seven new developments at this site.

Hydro Tech also performed a remedial investigation of the groundwater which consisted of the installation of both on-site and off-site monitoring wells. Based upon these results, we designed a remedial action plan which included the injection of ORC and Chemox. The injection has been successful in reducing the levels of gasoline compounds in the groundwater and we are now in the monitoring phase of the project.