What Goes Down
Must Come Up:
Addressing Vapor
Intrusion in New
York City
By Michael Heimbinder, HabitatMap
November, 2012
Vapor intrusion
describes the process whereby volatile chemicals migrate from
contaminated soil
and/or groundwater and enter buildings through cracks or perforations
in slabs
or basement floors. Tens of thousands of New Yorkers probably
unknowingly
breathe hazardous air contaminated with volatile organic compounds
(VOCs) on a
daily basis as a result of vapor intrusion. Frequently they do so in
the places
they feel most safe: in their homes, at work, or while at school.
Based on
faulty
assumptions, environmental regulatory authorities long held that vapor
intrusion was only an issue where the source of contaminants was
shallow and
the magnitude of contamination was extreme. Research and environmental
investigations conducted in the last two decades have proven these
assumptions
wrong. As a result, in 2006 the New York State Department of
Environmental
Conservation began re-evaluating
remedial
decisions
at 421 hazardous waste sites throughout the State. Fourteen of
these sites are located
in the five
boroughs, but evidence
indicates that
hundreds of
yet-to-be-identified homes, schools, and businesses are potentially
impacted by
vapor intrusion from VOC-contaminated soil and groundwater. The scale
of the
problem in New York City is unique because of its
high concentration, past and present, of PCE-using dry cleaners located
in dense
residential areas. (Data suggest that a vast majority of U.S. dry
cleaners have
released toxic VOCs into soil and/or groundwater.) Because New York
City
residents and policy-makers are largely unaware of the vapor intrusion
pathway
and the impact of exposure to VOCs on human health, thousands of New
Yorkers
continue to breathe hazardous concentrations of VOCs on a daily basis.
In
an effort
to raise awareness of the vapor intrusion problem in New York City, we
partnered with the Center for
Public Environmental Oversight
to create a
HabitatMap of all the properties
listed in the NYS Dept. of Environmental Conservation's Environmental
Site Remediation
Database.
The green flags mark properties where no VOCs were found to be present;
the
orange flags mark those properties where VOCs were found to be present;
and the
maroon flags mark those properties where Chlorinated VOCs (CVOCs) were
found to
be present. Because CVOCs tend not to degrade when contacting oxygen
near the
surface, they present a greater threat of vapor intrusion than other
VOCs, such
as compounds from petroleum spills. Note that the VOC and CVOC
contaminated
properties marked on the map represent only those sites that have been
placed
in the State Superfund Program or enrolled in the Brownfield Cleanup
Program.
The total number of CVOC impacted properties in New York City is
substantially
higher.
Human
exposure to
chlorinated solvents has been linked to the development of autoimmune diseases, birth
defects, nervous system disorders, infertility, and cancer.
Fortunately,
a properly installed and maintained mitigation system can eliminate the
threat
of hazardous vapor intrusion, protecting residents, students, and
employees
from the impacts of future exposures. Identical to radon systems,
mitigation
systems for vapor intrusion, also known as sub-slab depressurization
systems,
are an effective and low-cost solution for homes and buildings where
vapor
intrusion may be a problem.
It is unacceptable for the health of thousands of New Yorkers to be compromised by vapor intrusion when remedies are readily available and low-cost. To begin protecting New Yorkers we call upon the New York City Office of Environmental Remediation and the State Departments of Environmental Conservation and Health to institute a program to identify, map, and begin responding to VOC contamination in New York City groundwater. For starters, we urge them to:
* Create a public data base of all known data on VOC groundwater plumes in New York City, including all Phase II Environmental Site Assessments conducted by both public and private entities;
* Mandate groundwater and soil gas testing for all new construction in the City; and
* Require the routine installation of passive or active subslab depressurization systems on all new buildings in New York City, to prevent vapor intrusion.
Additional Resources
Center for Pubic Environmental Oversight "A Stakeholder's Guide to
Vapor
Intrusion"
DOH "Guidance
for Evaluating Residential Soil Vapor Intrusion in the State of New
York"
and fact
sheets on PCE and TCE
DEC "Vapor
Intrusion Guidance" and "Strategy
For Evaluating Soil Vapor Intrusion at Remedial Sites in New York"
NY State Assembly Report, "Vapor
Intrusion
of Toxic Chemicals: An Emerging Public Health Concern"
EPA Guide, "Building
Radon Out: A Step-by-Step Guide on How to Build Radon-Resistant Homes".
Radon sub-slab depressurization systems are identical to those used to
mitigate
vapor intrusion from chlorinated solvents or other VOCs.