[CPEO-BIF] Institutional Controls and Vapor Intrusion

[Lenny Siegel <lsiegel@cpeo.org>]

On behalf of CPEO, I just submitted comments to U.S. EPA on its Interim 
Final "Guide to Planning, Implementing, Maintaining, and Enforcing 
Institutional Controls at Contaminated Sites." The entire letter may be 
found at http://www.cpeo.org/pubs/CPEO-PIME.pdf. Because I have not seen 
elsewhere any detailed discussion of institutional controls as they 
apply to vapor intrusion sites, I am pasting here the section of my 
comments specifically addressing vapor intrusion.  - Lenny



Vapor intrusion responses raise a particular set of issues for 
institutional controls (ICs) that should be addressed in the "Guide to 
Planning, Implementing, Maintaining, and Enforcing Institutional 
Controls at Contaminated Sites," the final Vapor Intrusion Guidance, or 
both. ICs are typically used to prevent activity, such as construction, 
excavation, drilling for water, or even access. However, in vapor 
intrusion responses, ICs are necessary to require activity, such as 
sampling, mitigation (engineering controls), monitoring, and notice. 
That is, it is unusual for regulators to restrict land use based upon 
vapor intrusion risk. Instead, where there is a potential for vapor 
intrusion, exposure is prevented through engineering controls, such as 
sub-structure depressurization systems and vapor barriers. Institutional 
controls may be needed to ensure that such controls are applied where 
necessary, that they are operated successfully for the duration of the 
potential exposure, and that building owners and occupants are aware of 
the potential risk.

On source properties, the institutionalization of investigation, 
mitigation, long-term monitoring, and notice is relatively simple. 
Institutional controls on existing or new structures can require 
sampling, operation and maintenance of mitigation systems if necessary, 
and long-term monitoring to ensure that mitigation systems are operating 
or that indoor air contamination is below unacceptable concentrations. 
Unfortunately, at buildings occupied by non-owners such as tenants, 
employees, and students, there are few examples of informed notice. But 
that can easily be provided.

However, where volatile organic compounds migrate under nearby 
properties, there is a vapor intrusion risk to parties who are not 
responsible for the release. Accordingly, regulators normally do not 
force homeowners - or any other property owner for whom the risk is 
limited to the owner and his/her family - to accept sampling, 
mitigation, or monitoring. For a number or reasons, including the belief 
that the detection of vapor intrusion will reduce property values, many 
homeowners decline to cooperate. This is unfortunate, but understandable.

Here in Mountain View, homeowners adjacent to the MEW Superfund Study 
Area asked that their neighborhood be excluded from the vapor intrusion 
study area, because they were worried about the impact of that 
designation on their property values. EPA acceded, partly because all 
but one home - with unusual construction - tested had come up clean. I 
understand why my neighbors don't want to suffer financially from 
off-site pollution, but response programs must be designed carefully so 
the cost and/or health risk is not simply transferred to new owners and 
occupants.

Where property owners above an off-site plume agree to testing or 
mitigation, institutional controls can be used to require responsible 
parties to continue operation, maintenance, and monitoring. Again, 
that's relatively simple. In such cases, regulators are reluctant to 
require the off-site owners to continue to cooperate, but at the time of 
initial participation the owner should be required to agree to notify 
potential buyers or renters at the point of marketing of the vapor 
intrusion condition of the structure. This seems both fair and legal.

But what happens when a property owner refuses to cooperate at the 
outset of a vapor intrusion investigation? How can future buyers and 
tenants be warned and offered the response (sampling, mitigation, and 
monitoring)? A deed notice might let potential buyers know of the 
potential for exposure, but there is no comparable mechanism for 
potential tenants. Furthermore, a deed that identifies the potential 
risk does not let people know what they can do about it.

The same problem occurs where an owner initially cooperates but later 
"unplugs" a mitigation system. How can a new resident re-start 
mitigation and monitoring?

Moreover, there may be properties where the acknowledged risk of vapor 
intrusion increases because of continuing plume migration or the 
tightening of exposure standards. There needs to be a way to offer 
owners and occupants of those properties the same response offered to 
those initially believed at risk.

Therefore, I recommend that institutional controls at hazardous waste 
sites with a potential for off-site vapor intrusion require the 
responsible parties to continue offering vapor intrusion services 
(sampling, mitigation, and monitoring) as long as the potential for 
exposure continues.

Second, owners of existing rental property - including single family 
homes - with potential vapor intrusion should be required to accept 
sampling (and mitigation and monitoring if required). They should be 
required to notify prospective tenants of the potential for vapor 
intrusion, and they should be required to notify regulators whenever the 
tenancy changes - so regulators can offer additional information and 
guidance. Residents of owner-occupied homes who choose not to cooperate 
initially still should be required to cooperate and to notify 
prospective tenants, as well as regulators, whenever such a home is 
offered for rental. Since the obligations of landlords vary enormously 
across the country, implementing this condition will require legal research.

Third, residents of owner-occupied homes who choose not to cooperate 
initially still should be required to notify prospective buyers, as well 
as regulators, whenever such a home is offered for sale. That would give 
the buyers the opportunity to request vapor intrusion services. 
Disclosure requirements are also all over the map, so this too will 
require legal research.

If conditions require mitigation where new construction or building 
additions are proposed, property owners should not have the choice of 
opting out. There are several possible legal mechanisms for 
accomplishing this. Here in Mountain View, for large projects (over 
10,000 square feet) the city has required mitigation as Conditions of 
Approval under the California Environmental Quality Act (CEQA). Even 
projects too small for CEQA review may be required, through the building 
or planning permit processes, to mitigate.

Furthermore, if conditions at a new building require mitigation, 
potential renters and buyers should be notified at the point of 
marketing of the potential for vapor intrusion and the steps that are 
being taken to address it.

Finally, in determining whether conditions require mitigation at sites 
where new construction is planned, regulators should err on the side of 
caution because the cost of mitigation during design and construction is 
very low compared to the cost of retrofitting mitigation if vapor 
intrusion is discovered after construction. One way to do this is to 
require passive mitigation that can be made active (with the 
installation of a blower fan on an existing vent pipe) if 
post-construction sampling shows unacceptable contaminant levels 
indoors. That is, either site-specific institutional controls or 
building codes, as an alternative, should require mitigation in all new 
construction above or near any identified or suspected plume of TCE, 
PCE, or similar compounds. In cases, it may be possible for the builder 
to recover the additional expenses from the responsible parties. (In 
much of the country, there may be an additional reason to require vapor 
mitigation: the presence of naturally occurring radon in the subsurface.)

EPA and other government agencies have worked hard over the past several 
years to understand vapor intrusion: how to measure it and how to 
address it. Vapor intrusion investigations and responses are underway at 
a rapidly growing number of sites. But there are relatively few sites 
where institutional controls have been developed to ensure the long-term 
protection of off-site building occupants.




--


Lenny Siegel
Executive Director, Center for Public Environmental Oversight
a project of the Pacific Studies Center
278-A Hope St., Mountain View, CA 94041
Voice: 650/961-8918 or 650/969-1545
Fax: 650/961-8918
<lsiegel@cpeo.org>
http://www.cpeo.org


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