Scientists Respond

The EPA has been developing standards for water, soil, and air since the 1970s. Some standards are considered “not-to-exceed”, such as the EPA Maximum Contaminant Level (MCL) for lead in drinking water of 15 micrograms per liter (ug/L). These MCLs are typically adopted at the State level, including in Vermont, and can be enforced and involve fines if compliance cannot be met. The EPA also develops and publishes tables of “screening levels”, such as the Regional Screening Levels (RSLs) for soil, air, and tapwater. These screening levels are less enforceable, and are intended to trigger concern that will lead to voluntary cleanup or mitigation. Finally, the EPA publishes sector-specific screening levels, such as the 2009 guidance document, “Exposure Levels for Evaluating PCBs in Indoor School Air”. This publication states that the screening levels are intended to “guide thoughtful evaluation of indoor air quality in schools”.

In the 2009 guidance, the EPA applied conservative assumptions for PCB exposure to school-aged children, and developed a screening level of 600 ng/m3 for high-school aged children. The Vermont Department of Health (VT DOH) recognizes the EPA guidance, but then (2013) applied even more conservative assumptions, including children being inside a school building for 11 hours/day for 250 days/year with bulk exposure through diet rather than air, and developed a screening level of 15 ng/m3. Many in the environmental consulting community, while not necessarily all qualified toxicologists, believe that the EPA level is appropriate, and that the VT DOH’s assumptions are too conservative, leading to a level that is overprotective, exceedingly costly to comply with, and in some cases technically impracticable to achieve.

Miles E. Waite, PhD, PG
Senior Hydrogeologist
Waite-Heindel Environmental Management

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Closing the high school is a case of the cure being worse than the disease.

The science says that the kinds of PCB health effects cited by the DOH are due to ingestion through food or exposure to VASTLY higher airborne levels than we're seeing at BHS.

I have not seen any scientific evidence linking airborne PCB levels like we're seeing at BHS to negative health impacts. On the other hand, the mental health and educational costs of depriving children of in person school are well known, virtually certain and clearly significant.

It would be ideal to avoid every risk, but as a data scientist and former environmental regulator, I know that when you strive to manage one risk you are obliged to "balance accounts" by weighing the costs of doing so. I have not seen any evidence that the Dept of Health or the Dept of Education are doing this with the net effect that they are doing far more harm than good.

Greg Fanslow, MS
Data Scientist & President
Blue Tree Analytics

"EPA’s (note EPA, not Vermont) guidelines are likely more restrictive than needed, and the PCB-exposures at issue here are neither known nor reasonably expected to harm health."

Source: Cambridge Environmental Inc

Laura Green, PhD, D.A.B.T.
Senior Scientist and President
Cambridge Environmental Inc

(This is a response to a school in Massachusetts that had a similar situation as BHS)