Transcript Document 67127

VAPOR
What you don’t know
WILL hurt you.
O’Reilly, Talbot and Okun
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ENGINEERING
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
important;

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
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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
problems.
What Happens when VI is
Discovered?
• 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
chemicals.
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
detected.
Radon and Vapor Intrusion

Radon and VI occur when there is a source in the
ground;

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
Concrete?

When we look at concrete,
we see an impermeable
material.

But at the molecular level,
where gasses operate, it
looks like a bunch of
connected caverns that let
gasses pass through
easily.
What is Vapor Intrusion?
What Contaminants cause VI?

Gasoline

Petroleum Naphtha

Mineral Spirits

Dry Cleaning Solvent.

Among these the most
notorious is dry cleaning
solvents, usually
perchloroethylene.
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
problem.
• 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
problems.
• 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
seminar!
FIN
Quick Case Study
• Dry Cleaner
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(MassDEP)
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Fig 2-1 Basic elements
of the vapor intrusion
pathway

Figure 1-1:
Evaluation of vapor
intrusion potential
at sites where VOCs
have been released
to the environment.
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
Multiple Lines of Evidence
Multiple Phases (soil, groundwater, air,
product)
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Multiple Sampling Locations

Multiple Rounds
Dry Cleaning Solvent
PCE aka – perchloroethylene,
tetrachloroethylene
Units
Water: ug/liter ~ ppb
Air/Soil Gas: ug/cubic meter ≠ ppb
PCE
OSHA Ceiling Concentrations
200,000 ug/cubic meter
PCE
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
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ENGINEERING
Q&A
Environmental Safety Health Geotechnical