PCB Questions & Answers
What are PCBs?
- PCBs are a group of man-made organic chemicals consisting of carbon, hydrogen and chlorine atoms. The number of chlorine atoms and their location in a PCB molecule determine many of its physical and chemical properties. PCBs have no taste or smell, and range in consistency from an oil to a waxy solid.
- PCBs belong to a broad family of man-made organic chemicals known as chlorinated hydrocarbons. PCBs were domestically manufactured from 1929 until manufacturing was banned in 1979. They have a range of toxicity and vary in consistency from thin, light-colored liquids to yellow or black waxy solids. Due to their non-flammability, chemical stability, high boiling point and electrical insulating properties, PCBs were used in hundreds of industrial and commercial applications.
- Other example materials made prior to 1978:
- Light Ballast
- Specialty paints (mainly for steel)
- Adhesives
- Oil, grease, brake and hydraulic fluid
- Carbonless copy paper
What prompted the school district to test for PCBs at HCS?
- In light of the PCB findings at Burlington High School we looked at all of our schools and evaluated recent renovations to our buildings that were constructed between 1950 and 1978. Most of CVSD’s schools have had renovations that have removed the suspected material. While the White Building had extensive renovations in 1991, the windows have not been replaced since the mid 1960s. This prompted us to schedule testing in this space.
What material was suspected?
- The most common materials suspected to have PCBs is caulking and window glazing. This is what we had tested. PCBs can be found in other building material as well. But the White building was renovated in 1991 and at that time lighting and most of the finishes were replaced. Since PCBs were banned from building materials a decade earlier, these are not suspected and were not tested.
What testing has been done?
- Our first step was to conduct bulk material testing as a way to identify if PCBs were present in the window caulking. Unfortunately these results, received on December 8th, showed that PCBs are present in the window caulking at levels slightly above EPA action limits. Our consulting experts advised that it was highly unlikely that these levels in the material would result in air quality issues, but we immediately put plans in place for additional testing and for possible relocation of the classrooms.
- On January 13th, we took advantage of remote Wednesdays to close the building for 24 hours to conduct extensive air testing. At the same time, window sills and glazings were tested to determine if any PCBs had escaped as particulate. No detectable levels of PCBs were found in the air or on surfaces. The results conclusively tell us that occupants of the White Building are not being exposed to PCBs through inhalation, ingestion or dermal absorption.
What were the specific results of the bulk testing?
- The initial tests indicated that two locations had levels of PCBs that exceeded the EPA’s action threshold. EPA regulations say any bulk testing results greater than 50ppm require a remediation plan. We had 2 locations that exceeded that threshold. One room was 67ppm and the other was 1240ppm. To put this in perspective, the Burlington High School numbers were in the 100,000s PPM.
What were the specific results of the air and wipe tests?
- The follow-up testing was completed on January 13, 2021. A 24-hour air sampling process resulted in a report of “Non Detect”, i.e. there were no PCB’s detected in the air. The state of Vermont has a recommendation that air quality test results show a level less than 15ng/C3 (Nano gram/cubic meter). As PCBs exposure can also occur through ingestion or absorption through the skin, the windows were also tested for particulates. Wiping the window sills and glazing and testing the material found also resulted in a level of “Non Detect”.
What does this mean going forward?
- This summer we will be removing and disposing of the windows and the window glazing properly per the EPA and State regulations. As the building is on the historical registry we are working with specialists to match the historical character of the original windows.
Have there been other areas tested at HCS?
- Yes, in 2011 the district tested suspected material in limited areas in the 1956 and 1969 wings prior to a construction project. The test results were “Non Detect”.
Additional information
Environmental Protection Agency (EPA) Website
Vermont Department of Health Fact Sheet