Presentation to the Moffett Restoration Advisory Board May 11, 2017.

1. ACTIVITY NAME
Vapor Intrusion Update
Former Naval Air Station Moffett Field
Restoration Advisory Board Meeting
May 12, 2017
Vapor Intrusion Update
Installation Restoration (IR) Site 28
Former Naval Air Station Moffett Field
Restoration Advisory Board Meeting
May 11, 2017
Wilson Doctor
Navy Project Manager

2. 2 BRAC Program Management Office.
Update Topics
• Past Sampling Activities
• Site Background
• 2017 Sampling Scope
• Tiering Response Summary
• Future Activities

3. 3 BRAC Program Management Office.
Site Background
Schematic of Vapor Intrusion Pathway

4. 4 BRAC Program Management Office.
Site Background
IR INavy Area of Responsibility (yellow)

5. 5 BRAC Program Management Office.
Past Sampling Activities
• May - June 2012: Indoor Air Sampling
• May - June 2013: Soil Gas and Groundwater Investigation
• February 2014: Indoor Air Sampling
• September 2015: Groundwater Investigation
• January 2016: Indoor Air Sampling
• January 2017: Indoor Air Sampling
• Building 10 – Sampled Quarterly

6. 6 BRAC Program Management Office.
Building Surveys
• Prior to air sampling, 23 industrial/commercial buildings
were surveyed for any recent modifications in the layout
and operations of the HVAC systems
• Collected real-time readings for volatile organic
compounds using a hand-held photoionization detector
(PID) during building surveys
• PID readings used to optimize air sampling locations
• Interviewed building managers regarding building use,
operations, work hours of occupants, chemical use and
storage

7. 7 BRAC Program Management Office.
2017 Air Sampling
• A total of 211 samples were collected:
– 169 indoor air samples (first floor and basements)
– 13 pathway samples (i.e. crawl spaces, elevator shaft)
– 29 outdoor ambient air samples (background)
– Includes 8 samples from Building 10
• Samples collected with 6-liter canisters placed 36” to 60” above the
floor and analyzed for COCs by EPA Method TO-15 SIM (selected
ion monitoring)
• Buildings were sampled for 8, 10, or 24 hours, depending on use and
occupancy
• Buildings with an HVAC system were sampled twice:
– During work hours with the HVAC system operating
– 36 to 48 hours after the building ventilation system had been shut
down (following Martin Luther King Day weekend)

8. 8 BRAC Program Management Office.
2017 Air Sampling Photos
Outdoor Ambient Sample Pathway Sample Indoor Sample

9. 9 BRAC Program Management Office.
Indoor Air Cleanup Levels for
Long-Term Exposure
ROD Amendment for the Vapor Intrusion Pathway (EPA, 2010)
Chemical of Concern
Indoor Air Cleanup Level (μg/m3)
Commercial for Long-Term Exposure
Trichloroethene 5
Tetrachloroethene 2
cis-1,2-Dichloroethene 210
trans-1,2-Dichloroethene 210
Vinyl Chloride 2
1,1-Dichloroethane 6
1,1-Dichloroethene 700

10. 10 BRAC Program Management Office.
SUMMARY OF TIERING SYSTEM AND RESPONSE
ACTIONS FOR EXISTING COMMERCIAL BUILDINGS
Tier Description Response Action
1 Building with indoor air concentrations
greater than outdoor (background) air
concentrations and indoor air cleanup
levels.
• Implement selected remedy to meet indoor air cleanup levels.
• Once indoor air cleanup level is achieved and confirmed, building is
recategorized as Tier 2.
• Implement governmental, proprietary, and information institutional controls.
2 Building with indoor air concentrations
below the indoor air cleanup levels, while
an engineering control is in place or in
operation. Also, former Tier 1 buildings
with confirmed indoor air concentrations
that are below the indoor air cleanup
levels.
• Ensure continued operation and maintenance of active ventilation system or
other selected engineered remedy to meet remedial action objectives.
• Develop and implement long-term monitoring and institutional controls
implementation plan.
• Where remedy is achieved through operation of an active ventilation system,
agreement of property owner must be contained in a recorded agreement.
3A Building sampled without engineering
control in place or operating with indoor
air concentrations below indoor air
cleanup levels, but greater than outdoor
(background) concentrations.
• No engineered remedy required. Develop and implement long-term
monitoring plan. Implement governmental institutional controls.
3B Building sampled without engineering
control in place or operating with indoor
air concentrations at or within outdoor air
(background) concentrations.
• No engineered remedy or long-term monitoring required. Implement
governmental institutional controls.
4 Buildings where converging lines of
evidence demonstrate that there is no
longer the potential for vapor intrusion
into the building exceeding indoor air
cleanup levels.
• No action required after performance of all necessary confirmation sampling
and documentation approved by USEPA that no action is necessary.

11. 11 BRAC Program Management Office.
Draft 2016 Tier Evaluation
• Tier 1: Buildings 45, 126, 567
• Tier 3A: 2, 3, 10, 12, 13, 14, 15, 16, 29, 67, 76, 107, N210,
N239, N239A, N243, N243A, 510, 555, 566

12. 12 BRAC Program Management Office.
Future Activities
• A detailed building tiering evaluation will be included in the
Draft 2017 IR Site 28 Air Sampling and Vapor Intrusion Tier
Response Evaluation Report (scheduled for June/July 2017)
• Continue with CERCLA process

13. 13 BRAC Program Management Office.
Air Sampling for Vapor Intrusion
QUESTIONS ?