"Due to building conditions, sub-slab soil vapor samples were omitted during the SVI investigations at Property 2 and Property 10. At Property 2, the presence of standing water and shallow groundwater beneath the building slab prevented the collection of sub-slab soil vapor samples. A sub-slab soil vapor sample was not collected at Property 10 to avoid damaging a sub-slab geothermal heating system located under the structure. In each case, SVI structure sampling was limited to the collection of indoor and outdoor ambient air samples."

See page two: Site Characterization – Soil Vapor Intrusion Results - 473 President Street Off-Site

Property 2 was identified with "the presence of standing water and shallow groundwater beneath the building slab... (bold is emphasis added)" The "Final Action Recommended" for Property 2 was, "Mitigate."

Property 10 received a "No Further Action" determination. It did not received a Final Action Recommendation to, "Mitigate."

Conclusion

Of the 14 properties investigated for Soil Vapor Intrusion as part of the 473 President Off-Site Characterization Soil Vapor Intrusion monitoring effort, 543 Union Street is the only property that has confirmed standing water and a sub-slab mitigation system. It is irrefutably Property 2.

Soil Vapor Intrusion Mitigation System in Basement of 543 Union Street With Standing Water Present