Targus was retained to perform an environmental site assessment (Phase I ESA and additional non-ASTM services) of a prominent downtown office tower with an underlying five-story subgrade parking garage. The property had been constructed on the site of a locally notable manufactured gas plant (MGP) and surrounding disposal sites.
Targus’ research of regulatory records and limited provided information indicated that a large body of waste tar and related contaminants from the prior MGP operations and disposal had unexpectedly been encountered during excavation. Although a considerable quantity of waste had been removed from the building footprint, contaminated groundwater remained in the surrounding area. Review of construction documents and drawings identified that the excavation extended to the full property boundary and that the bottom extended to an aquitard. The basement garage perimeter had been constructed with a water-resistant wall and was protected from hydrostatic pressure by an exterior drainage system.
Although not identified in provided information or readily visible, Targus’ field representative identified the presence of an on-site sump served by a water treatment system. Additional research confirmed that the discharge had been routed to the municipal stormwater system. Evaluation of the treatment system, confirmed by sampling and analysis, demonstrated that the treated water met discharge criteria applicable to that stormwater sewer.
Targus considered the documented surrounding groundwater (and presumed vapor) impact limited to the mechanically-ventilated garage to be a recognized environmental condition. Targus evaluated prior expenditures for operation and maintenance of the discharge treatment system and opined that since these costs appeared to be sufficiently budgeted, the recognized environmental condition would not be a business environmental risk – subject to continued permit compliance.
