Tim Kemper, PE, LSP, Client Program Manager, Shaw Environmental and Infrastructure Group - April 2012

1. Vapor Intrusion Case Study: Unexpected VI Issue Arises During Brownfield
Property Redevelopment Project in Massachusetts
Tim Kemper, PE, LSP
Program Manager
The Shaw Group

2. Case Study – A Brief Chronology
► Former industrial metal-working
facility
– 1964: Original manufacturing building
constructed (40,000 ft2) on two-acre
parcel
– 1964-1997: Chlorinated solvents (TCE)
used on site for metal degreasing.
Waste materials reportedly “recycled
off site and disposed to sanitary sewer”
– 1980s & 1990s: Several small releases
reported to MADEP by various owners
– 1998: Manufacturing company filed for
bankruptcy
– 1998-2004: Building abandoned and
property blighted
– 2004-2006: New owner. Building
renovated for warehouse use
– 2006: Vapor intrusion issue detected
after renovation
– 2007-2010: IAQ monitoring, vapor
mitigation, site remediation, and MCP
environmental closure
01M042012D
VAPOR INTRUSION CASE STUDY 2

3. Abandoned Vacant Manufacturing Building
(March 2004)
01M042012D
VAPOR INTRUSION CASE STUDY 3

4. New Warehouse Building (February 2006)
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VAPOR INTRUSION CASE STUDY 4

5. Vapor Intrusion and TCE Concentrations Increase
during Building Renovation
Average Soil Vapor TCE Concentration vs. Time
900,000
800,000
768,638
700,000
Building
heated &
600,000
TCE Concentration (ug/m3)
used as
warehouse
500,000
400,000
Building
349,080
300,000
renovation
complete
Building abandoned
200,000
with holes in roof
Building
100,000
9,184 renovation in
8,218
progress
0
March 2004 March 2005 January 2006 February 2006
Date
01M042012D
VAPOR INTRUSION CASE STUDY 5

6. VI Solution –
a Soil Vapor Extraction & Remediation System
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VAPOR INTRUSION CASE STUDY 6

7. Vapor Control and Treatment System
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VAPOR INTRUSION CASE STUDY 7

8. TCE Concentrations in Indoor Air reduced
by SVE System
Average Indoor Air TCE Concentration (ug/m3) vs. Time
180
170
169 (without ventilation)
160
150
140
130
120
110
100
90
80
70
58 (with ventilation)
60
50
40
30
20
10
18 (with SVE system)
0
March 2006 May 2006 Oct. 2006
TCE = trichloroethene
MADEP = Massachusetts Department of Environmental Protection
Date
01M042012D
VAPOR INTRUSION CASE STUDY 8

9. VI Case Study Summary & Lessons Learned
► Pre-transaction due diligence established escrow for identified soil and
groundwater (GW) remediation outside building footprint based on existing data
► Vapor Intrusion was not suspected as: no known sub-slab VOC
sources, groundwater levels < MCP GW-2 standards and GW depth >15 feet
below grade
► Previous environmental assessments unable to discover key VOC source under
building (unidentified leaky floor drain system)
► Building renovations (new roof, insulation and heating system) and resultant
“chimney effect” caused a significant increase in soil vapor intrusion (100x) into
indoor air
► Significant remediation costs (~$200,000) required to treat soil beneath building
for abatement of VI issue
► VI issues from unidentified sub-slab VOC releases drove site remediation – not
soil and GW contamination previously reported to MADEP
► Beware of potential VI issues from sub-slab sources!
01M042012D
VAPOR INTRUSION CASE STUDY 9

10. CONTACT
Tim Kemper, PE, LSP
The Shaw Group
+1 617.589.6162
tim.kemper@shawgrp.com