PCE / TCE Vapor Intrusion Mitigation
Commercial Property with Historic Industrial Usage
Challenges:
Perchloroethylene (PCE) and trichloroethylene (TCE) were found in groundwater and indoor air during due diligence investigations for a commercial property being marketed for redevelopment. Recent changes in MassDEP’s indoor air risk-based values meant that an imminent hazard condition existed. The building owners were faced with the possibility that the tenant would have to be relocated, the remaining 18 months of the lease terminated and $100,000 of revenue lost.
Solutions:
In less than one week (most of the work completed during off-hours and over the weekend), the following actions were taken to abate the imminent hazard condition:
Indoor air testing consistently showed that these measures abated the imminent hazard condition and in fact, the concentrations of TCE and PCE were reduced to near non-detectable levels. The tenant did not have to relocate, which was the desired outcome for both the building owners and the tenant.
ES&M supported the owners during the sale of the property by preparing detailed cost opinions, assisting with procurement of a loan from Mass Development, and assisting with escrow negotiations. As a result of our professional approach, the owners were able to complete the sale of their property.
Perchloroethylene (PCE) and trichloroethylene (TCE) were found in groundwater and indoor air during due diligence investigations for a commercial property being marketed for redevelopment. Recent changes in MassDEP’s indoor air risk-based values meant that an imminent hazard condition existed. The building owners were faced with the possibility that the tenant would have to be relocated, the remaining 18 months of the lease terminated and $100,000 of revenue lost.
Solutions:
In less than one week (most of the work completed during off-hours and over the weekend), the following actions were taken to abate the imminent hazard condition:
- A robust sub-slab depressurization system was installed. The system extracted soil gas from four locations beneath the 9,300 square foot building floor using a regenerative blower and activated carbon treatment. Treated soil vapor is discharged through an unused chimney.
- Modifications were made to the HVAC system to create positive pressure inside the building;
- Carbon impregnated filters replaced the standard HVAC air filters;
- An old chimney was sealed to eliminate the slight negative pressure that was drawing TCE and PCE into indoor air from the subsurface;
- Cracks in the basement floor and walls were sealed;
- A simple carbon adsorber and recirculation fan was installed in the basement to capture TCE/PCE before it could migrate from the basement into the occupied portions of the building; and
Indoor air testing consistently showed that these measures abated the imminent hazard condition and in fact, the concentrations of TCE and PCE were reduced to near non-detectable levels. The tenant did not have to relocate, which was the desired outcome for both the building owners and the tenant.
ES&M supported the owners during the sale of the property by preparing detailed cost opinions, assisting with procurement of a loan from Mass Development, and assisting with escrow negotiations. As a result of our professional approach, the owners were able to complete the sale of their property.
