There has been a push in my home state of Connecticut to test more schools for PCBs. While no doubt well intentioned, this initiative is driven by two misguided assumptions:
1. That the presence of PCBs in schools pose a hazard to the building’s users; and
2. That if PCBs are discovered in a school it is a relatively simple matter to remove them.
The good news is that the first assumption is wrong, there is in fact no scientific evidence that PCBs in schools pose a hazard to the building’s users. The bad news is that the second assumption is also wrong, removing PCBs from a building is anything but simple; it can be an extremely difficult and expensive endeavor. Let me get into a little more depth on each of these questions.
Do PCBs in schools pose a health risk?
When you ask a toxicologist whether a chemical poses a health risk, the response you’re likely to hear is: “that depends on how much of the chemical someone is actually exposed to”, or to phrase it more succinctly, “that depends on the dose”. You see every chemical, even water, can be toxic (even deadly) under some conditions and in some doses. So answering the question of whether something is toxic requires an understanding of the exposure conditions and the dose. So let’s look at the conditions and PCB doses that a child is exposed to in a school situation.
Between 1950 and the early 1970s PCBs were used in a variety of building materials that might be found in schools including: caulk, paint, floor wax, adhesives (mastic) and surface coatings. PCBs were used in these products because they added durability and useful life to the products. The USEPA has determined that the most likely way for people to be exposed to PCBs in buildings is by inhalation. Although PCBs are not particularly volatile, small amounts do volatilize out of building materials over the course of years and decades.
These low concentrations of PCBs in air can be measured and the dose that a building occupant might be exposed to from inhaling them can be estimated. Based on this exposure mechanism the USEPA has developed PCB Public Health Levels that it considers to be safe for school children. The average daily PCB dose corresponding to EPA’s Public Health Level for an elementary school child is about 0.94 micrograms, a little less than one microgram per day.
To assess whether one microgram per day is a risky daily dose or not it’s helpful to compare it to the amount of PCB an elementary school child receives in their diet. You see PCBs are widely distributed in the environment and they are present in our food supply, particularly in animal products like meat and fish. Based on data developed as part of a recent market basket survey by the University of Texas, the average American elementary school child is exposed to about 4.6 micrograms of PCBs a day in their diet (much of this from hamburger and fish). That’s about 5 times more than they would receive by inhalation while attending a school with PCBs at USEPA’s Public Health Level.
So even if the concentration of PCBs in school air is four times USEPA’s public health level, it would still not equal the amount of PCBs an average elementary school child receives daily in their diet. For someone concerned about PCB exposures in schools the most effective place to make changes might be in the cafeteria menu and not in the building materials.
How hard and expensive can it be to remove PCBs from schools?
The simple answer is that removing PCBs from a building where they have been in place for over 30 years is really hard and very expensive. Here’s the problem: unless PCBs are in a laboratory sealed container, they tend not stay where they were put and over the years and decades they continue to move around. So a PCB containing caulk bead placed in the gap between a window frame and a brick or concrete wall will result in the PCBs migrating out of the caulk and into the abutting brick or concrete, with each passing year moving a little deeper into the brick or concrete. But that’s not all. The PCBs from the caulk bead also volatilize slowly into the air and then condense onto other building surfaces remote from the caulk bead. The PCB load on these remote surfaces slowly increases over time.
So removing PCBs from a school building involves more than just taking out the PCB source material, it also means identifying other materials in the building that may have become contaminated either directly or indirectly as a result of the PCB source. It often means deciding how to manage building structural components that have become contaminated with PCBs.
How do School Administrators Learn about PCBs in their Buildings?
How do school administrators learn about PCBs in their schools? Usually by surprise. Here’s how it often happens: The school district receives a grant for a window or sprinkler replacement project for an old school. The facilities department develops project plans and specifications and then lets out a contract for the work to the lowest qualified bidder. The work begins and continues until one day the facilities department hears from the contractor that PCBs have been discovered. The project grinds to a halt and the contractor recommends more testing.
The contractor’s first estimate for additional costs to manage the PCBs is high, but within the project’s budget reserve. However, as more test results become available and PCBs are found to be more wide spread than originally anticipated, cost estimates zoom past the reserve amount. This is when senior administrators or boards of education start asking questions, but by then the options for alternative action are limited.
TSCA – the Law of Unintended Consequences
You can read the Toxic Substances Control Act (TSCA) from cover to cover and you’ll find nothing about removing PCBs from schools or other buildings. Take a look at the 800+ page legislative history of TSCA and you will still find nothing about PCBs in schools. How about EPA’s PCB regulations (40 CFR 761)? No, still nothing about removing PCBs from schools or other buildings. So if there is nothing in the statute or the regulations about removing PCBs from schools or other buildings, and if there is no evidence that PCBs in building materials pose a health risk, then what explains the need to assess and remove PCBs from schools? Stay tuned for part 2.