In a fact sheet released Friday, the New York State Department of Environmental Conservation downgraded the land at Clinton West Plaza to a Class 4 site, meaning it "no longer poses a significant threat to public health and/or the environment."
Before the reclassification, the plaza site, listed as 609-625 West Clinton Street was listed as Class 2, having been investigated in 2005 and found to contain chemicals from a laundromat that had previously occupied part of the site. The investigation found vinyl chloride, trichloroethene, tetrachloroethene and dichloroethene.
A remediation plan was introduced and improved in mid-2016. It contained the following measures, which according to the state have rehabilitated the site to the point of relative safety.
"Remedial activities completed at the site included in-situ chemical oxidation treatment of groundwater in the southwestern portion of the site," the report states. "This involved injection of a carbon source to further degrade contamination; and the construction of a cover system comprised of building slabs, concrete, pavement, and 2 feet of clean soil. In addition, sub-slab depressurization systems were installed in one on-site building and one off-site building to mitigate the potential for exposures as a result of soil vapor intrusion."
Groundwater at the site is still unusable for the public, and the site's uses are still restricted by DEC-mandated regulations.
Other air quality maintenance practices have made the air around the site safe as well, helped by subterranean filtration systems.
"A sub-slab depressurization system (system that ventilates/removes the air beneath the building) has been installed in the on-site building and one off-site building to prevent the indoor air quality from being affected by the contamination in the soil vapor beneath the building," the report states. "Sampling indicates that soil vapor intrusion is not a concern for other off-site buildings."