[CPEO-IRF] Vapor Intrusion sites at McClellan Air Force Base (CA)

[Lenny Siegel <lsiegel@cpeo.org>]

The Air Force Real Property Agency is holding a public meeting on 
Wednesday, July 13, 2005 on its Proposed Plan for Soil Gas Mitigation at 
former McClellan Air Force Base, Sacramento, California (BRAC 95). In 
question are two sites at the southwestern portion of the former base. 
At Site PRL T-46, former site of a removed oil/water separator tank, the 
Air Force has concluded, with state concurrence, that there is no need 
for further action.

However, at Site SA-16, the Air Force concluded that the residential 
risk from exposure to naphthalene and benzene vapors would be 
approximately 100 in a million, but considers it acceptable. Its 
proposed solution is an institutional control against residential use on 
the site.

"SA 16 (Benzene, Ethylbenzene and Naphthalene), proposed for 
institutional controls: This site contains open hangars that were used 
for aircraft maintenance and fueling and defueling operations. There are 
records of jet fuel spills, and the potential exists for subsurface 
releases of fuels and associated materials. During recent investigations 
at the site, over 80 samples were taken. Major vapor intrusion pathway 
contaminants include, ethylbenzene, elevated in one sample, and benzene 
and naphthalene, elevated in two samples each.

"The risk from the vapor intrusion pathway does not exceed the 
acceptable risk range for unrestricted use. (Risk range and how it is 
used is described in more detail in section E.) However, sufficient 
uncertainty exists concerning the total risk at the site that the Air 
Force is proposing to limit the use of the property to industrial 
activities until the total risk is better defined during remedy design. 
This would be accomplished using institutional controls which would 
preclude residential use of the sites by the use of zoning and deed 
restrictions. By limiting activities at the site, the occupant's 
exposure and consequent risk is greatly reduced."

The state of California disagrees with this proposal.

The Air Force proposed plan is attached as a 700K PDF file.

--
Lenny Siegel
Director, Center for Public Environmental Oversight
c/o PSC, 278-A Hope St., Mountain View, CA 94041
Voice: 650/961-8918 or 650/969-1545
Fax: 650/961-8918
http://www.cpeo.org

Attachment: mccln_final_ssgpp.pdf
Description: Adobe PDF document

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