Research on PCBs in Caulk
September 2009
Overview
Caulk containing polychlorinated biphenyls (PCBs) was used in some buildings, including schools, in the
1950s through the 1970s. EPA is taking action to respond to this potential problem in multiple ways.
To aid schools in the near term, EPA is providing schools with information to determine if they have
PCBs in caulk and tools to properly manage contaminated caulk to help minimize exposures. To better
understand the problem, EPA plans to conduct research on PCB-contaminated caulk and other potential
sources of PCBs in schools.
Research Goals
EPA research on PCBs in schools is being designed to identify and evaluate potential sources of PCBs in
order to better understand exposures to children, teachers, and other school workers, and to improve
risk management decisions. EPA will investigate PCB-contaminated caulk, as well as other potential
sources of PCBs in schools. Specifically, EPA's Office of Research and Development will:
•	characterize potential sources of PCB exposures in schools (caulk, coatings, light ballasts, etc.)
•	investigate the relationship of these sources to PCB concentrations in air, dust, and soil
•	evaluate methods to reduce exposures to PCBs in caulk and other sources
Proposed Research
Sources of PCBs and the Relationship to PCB Concentrations in Air, Dust, and Soil
To understand the significance of PCB-contaminated caulk as a source of PCB exposures in school
buildings, research is needed to better characterize the sources of PCBs in buildings and the potential
exposures in schools. EPA is developing a research plan to: (1) characterize PCB-contaminated caulk
and other potential sources of PCBs in schools; (2) measure PCB concentrations in air, dust and soil in
selected schools and investigate relationships to the potential sources (e.g., caulk, other building
materials, coatings, ballasts); (3) evaluate which routes of exposure (e.g., inhalation, contact with dust)
are most important; and, (4) collect data to assist in developing risk management practices for reducing
exposure to PCBs in schools.
This research will consist of both field and laboratory components. The field research will involve data
collection and environmental measurements at selected schools. This will include collection of materials
at the schools for laboratory analyses and subsequent chamber tests to characterize PCBs in
contaminated caulk and other PCB sources. The field measurement study will involve recruitment of a
limited number of schools with PCB-contaminated caulk to participate in the study. This will allow more
intensive characterization of PCB sources and environmental measurements that can be used to better
understand the relationships between sources, environmental concentrations in selected media (dust
and air), and potential exposure estimates. At each school, PCBs will be measured in indoor and
outdoor air, in soil adjacent to the building, and in dust on floors and other surfaces at multiple
locations within the school building. Sources of PCBs, such as caulk around windows and doors, will be
sampled and returned to the laboratory for analyses. Information will be collected at each school on
building characteristics, building materials, ventilation systems, and other factors that may affect the
distribution of PCBs in the school building and the potential for exposure. EPA will use the
measurement study information as input data into ORD's Stochastic Human Exposure and Dose
Simulation (SHEDS) model to predict population distributions of multi-media exposures for school-age
children, teachers, and other workers under selected scenarios. The field study is planned to begin
once schools have been identified and access has been granted. It is expected that this portion of the
research will be completed in 12 to 18 months. A critical element for success of the field research effort
will be for EPA to identify schools that will participate in the research study.
In the laboratory, EPA will conduct tests on materials collected in the field to address several key
questions regarding the PCB sources, including: (1) determination of PCB off-gassing from caulk and

-------
other PCB sources collected from buildings; (2) determination of PCB distribution between sources and
indoor media (air, dust, and interior surfaces); and, (3) determination of PCB migration rates from
sources to settled dust. The laboratory tests will determine how PCBs in caulk and other sources have
migrated to adjacent materials, interior sources and settled dust over time to allow EPA to better
understand the distribution of PCBs inside buildings. These results will also help EPA improve
monitoring practices and reduce uncertainties in exposure assessments. Data collected in both the field
and laboratory will be used by EPA to assist in the development of improved management practices for
reducing exposure to PCBs in schools.
Mitigation Methods to Reduce Exposures to PCBs in Caulk and Other Sources
EPA recognizes that when PCB-contaminated caulk is identified in buildings, resources are sometimes
not available to immediately remove all of the caulk. Interim methods are sometimes needed to reduce
human exposure to PCBs during the time before the caulk is removed. For example, PCB-contaminated
caulk may be temporarily covered with a barrier or a coating to prevent people from coming into
contact with PCBs. After the removal of caulk, a related issue is that surrounding building materials
may be contaminated with PCBs that have migrated from the caulk. Surrounding materials such as
wood and wallboard can be removed in some cases, but materials such as concrete, brick, and mortar
are more difficult to remove. PCBs from these surrounding materials can then leach into newly applied
caulk. Therefore, coatings might also be employed to encapsulate surrounding materials contaminated
by PCBs to prevent future migration and release of PCBs into new caulk or the environment.
To determine effective mitigation methods, EPA is planning to evaluate coatings that may be used to
encapsulate materials contaminated by PCBs from caulk. Initial laboratory screening tests will be used
to evaluate many types of coatings, including epoxy, polyurethane, polyurea, lacquer, oil-based paint,
latex paint, and others. These coatings will be screened for their ability to resist penetration by PCBs.
The most promising coatings identified in the screening tests will then be more rigorously tested in the
laboratory to evaluate short- and long-term encapsulation abilities, cost, and feasibility for use in
buildings. ORD will evaluate other techniques, along with coatings used as encapsulants, as potential
mitigation methods.
EPA plans to begin mitigation testing in 2009. Once testing is complete, EPA will prepare a summary
report that combines results from these EPA studies with information from the literature. The report
will be available to the public. The information will also be used by EPA to develop guidance on
mitigation methods for PCB-containing caulk and to inform future risk management decisions.

-------