Document 67127

What you don’t know
WILL hurt you.
O’Reilly, Talbot and Okun
[ A S S
E S ]
Today’s presenters:
James D. Okun, Principal
Kevin J. O’Reilly, Principal
Environmental Safety Health Geotechnical
What we will cover today
Why learning about Vapor Intrusion (VI) is
Back ground – What is Vapor Intrusion;
What MassDEP is doing with VI; and
A case study illustrating some of the problems
at VI sites.
O’Reilly, Talbot and Okun
[ A S S
E S ]
Why Should you be Concerned?
• If you own, operate or accept property as
collateral, vapor intrusion may be your
most important environmental risk.
• An ASTM environmental site
assessment offers protection from
federal CERCLA liability, but in
practice CERCLA liability is
relatively uncommon.
• VI risk is far more common, but a
standard Phase I ESA will not
necessarily identify potential VI
What Happens when VI is
• The response from state regulators can
vary from requiring more testing to
insisting that occupancy of the building
be suddenly discontinued.
• The regulators have broad latitude in
these situations.
So what is Vapor Intrusion?
• Vapor intrusion is what happens when
volatile chemicals in the ground
migrate up and into overlying buildings.
• Once in the buildings, these chemicals
get into the air that people breath.
• It is one of the most serious ways that
people can be exposed to hazardous
Was Vapor Intrusion Just
Recently Discovered?
 No, MassDEP was among the first environmental agencies
in the nation concerned about VI back in 1993 when the
current cleanup law was first enacted.
 At that time scientific thinking was that VI was uncommon,
occurring only rarely.
 Newer studies prove that this view was mistaken.
 VI is now understood to be more common and
potentially serious.
Why Haven’t I Heard about VI?
It is only in the past few years that environmental scientists
realized the models they were using significantly under-predicted
the VI problems.
Information about the new analysis of VI is just getting through to
the real estate community now.
Is VI Similar to Radon Gas?
Yes, radon acts by the
same mechanisms as
does VI.
VI and radon are invisible,
have no odor and require
technical tests to be
Radon and Vapor Intrusion
Radon and VI occur when there is a source in the
A preferential pathway that channels to radon or
VOCs from the source location to beneath a
building; and
A driving force that draws the radon or VOCs into
the indoor air of a building.
Is VI just a Theory or is it Real?
Hard to believe the first time
you hear about it, but it’s
definitely real.
Soil particles only take up
60-70% of a volume of soil,
the rest is gas. These void
spaces permit the movement
of chemical vapors.
Do Radon and VOCs go Through
When we look at concrete,
we see an impermeable
But at the molecular level,
where gasses operate, it
looks like a bunch of
connected caverns that let
gasses pass through
What is Vapor Intrusion?
What Contaminants cause VI?
Petroleum Naphtha
Mineral Spirits
Dry Cleaning Solvent.
Among these the most
notorious is dry cleaning
solvents, usually
If I know My Property is Clean,
do I Still Need to Worry about VI?
• Unfortunately, you do. Some
chemicals move underground as
much as a half mile from the
disposal area to cause a VI
• While a half mile movement of a VI
issue is unusual, migration of a few
hundred feet is not.
• In an urban environment, VI
problems can be common.
Why is indoor air testing an
unreliable approach to VI testing?
• People intuitively think indoor air
testing is a good way to assess VI
• Indoor air testing is actually an
unreliable approach because it is
prone to false readings.
• For instance alcohol, fingernail polish,
smoke, cleaners and paints
• That’s because there are other
sources of VOCs in buildings and
daily conditions can affect results
positively or negatively.
Best Testing Approach
Ideally, a sample of soil gas is
collected from beneath the floor
slab of the building.
To do this a small hole is drilled
through the floor and sample
equipment is installed.
The sample is carefully
withdrawn from beneath the floor,
collected in a special canister
and delivered to a laboratory for
chemical analysis.
The lab is able to detect very low
concentrations in the air sample.
What Happens to a VI Property?
In Massachusetts, VI is what
I call the roach motel of
environmental regulation; you
can check in, but you can
never check out.
Under the current
regulations, once a property
is tagged as having a VI
problem, achieving a
“permanent solution” status
can be impossible.
Recent Regulatory Response
• For the past few years, vapor intrusion has been the number
one issue being addressed by MassDEP.
• Starting in 2007, MassDEP initiated
an unprecedented re-evaluation of
over 600 site closures and required
new response actions at over 100 of
them due to concerns about the
possibility of vapor intrusion.
Groundwater and AULs
• Even in cases where there is no evidence that VI is taking
place – that is there are no VOCs in indoor air – MassDEP
will still require a Notice of Activity and Use Limitation (a
deed notice) if groundwater VOC concentrations exceed the
GW-2 standards.
• This requirement is to address the possibility that a future
building may not be as effective as the current building at
minimizing potential VI impacts.
• This is a controversial requirement because it is based on the
occurrence of a possible future problem.
• AULs are expensive to prepare, and in the past have been
audit magnets.
What is MassDEP up to Now?
 DEP has been struggling to come up with a regulatory
approach to VI for over 3 years.
 There were two major draft guidance documents issued
before they realized new regulations would be needed in
addition to thick guidance documents.
 As of now, it looks as if any property with a theoretical risk
of VI occurring, whether it is actually occurring or not, will
be required to have an AUL as a matter of regulation, not
just guidance.
Look for More Regulatory Changes
 DEP has a very full plate of regulation changes slated
for the waste site cleanup program.
 Over the next few months they will be floating draft
versions of many proposed regulation changes.
 Their ambitious goal is to have the changes in-place by
July 1, 2012.
 At which time we may need to have another breakfast
Quick Case Study
• Dry Cleaner
Fig 2-1 Basic elements
of the vapor intrusion
Figure 1-1:
Evaluation of vapor
intrusion potential
at sites where VOCs
have been released
to the environment.
Multiple Lines of Evidence
Multiple Phases (soil, groundwater, air,
Multiple Sampling Locations
Multiple Rounds
Dry Cleaning Solvent
PCE aka – perchloroethylene,
Water: ug/liter ~ ppb
Air/Soil Gas: ug/cubic meter ≠ ppb
OSHA Ceiling Concentrations
200,000 ug/cubic meter
MassDEP “No Significant Risk” Estimate
Residential: 2.3 ug/cubic meter
Commercial: 13 ug/cubic meter
MassDEP “Imminent Hazard” Estimate
Residential: 14 ug/cubic meter
Commercial: 50 ug/cubic meter
O’Reilly, Talbot and Okun
[ A S S
E S ]
Environmental Safety Health Geotechnical

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