The EPA says 600 nanograms is safe. Vermont closes classrooms at 100. What do they know that the rest of the country doesn’t?

by Dave Soulia, for FYIVT.com

When air tests at Burlington High School revealed polychlorinated biphenyls (PCBs) in 2020, the numbers were shocking: indoor air concentrations as high as 6,300 nanograms per cubic meter. That’s more than ten times higher than what the EPA recommends for high school students. Burlington shut the building down, and the state of Vermont launched what would become one of the most aggressive PCB mitigation efforts in the country.

But fast-forward to 2025, and a new question looms: Has Vermont overcorrected?

A Lone Ranger in School Air Standards

The EPA — not exactly known for leniency on environmental health — sets indoor PCB air guidelines for schools based on age. For older students and adults, the exposure level considered safe is up to 600 ng/m³. In contrast, Vermont’s “School Action Levels” cap exposure at 100 ng/m³ for seventh graders and up — six times more stringent than federal guidance.

And it’s not just high schoolers. For kindergartners, Vermont demands levels below 60 ng/m³. Pre-K students? Just 30 ng/m³.

No other state has followed suit — not even California, famous for its cautionary cancer warnings and aggressive environmental policies.

📊 Comparison of PCB Air Thresholds in Schools (ng/m³)

Note: SAL = School Action Level (Vermont); ELE = Exposure Level for Evaluation (EPA)

What the Science Actually Says

PCBs are synthetic chemicals used widely in electrical and building materials from the 1950s through the late 1970s. They were banned in 1979, but linger in caulking, light ballasts, paint, and concrete in older buildings — especially schools.

There’s no debate that PCBs are harmful. High exposure has been linked to developmental delays, endocrine disruption, and even cancer. But most of that data comes from ingestion and occupational studies — not low-level inhalation in classrooms.

The EPA’s thresholds already reflect a conservative model, assuming students spend 6 to 8 hours a day in the same room, 180 days a year, for multiple years.

But modern schooling just doesn’t work like that.

Middle and high school students move from class to class every 45 minutes. They rotate through dozens of rooms, labs, and electives. Real exposure time in any one space is minimal.

Millions Spent, Minimal Risk?

Under Vermont’s standards, schools have been forced into expensive remediation when air samples come back at 200 ng/m³ — levels the EPA doesn’t even flag for concern.

North Country Union High School, for example, triggered a $5 million cleanup after readings peaked at 250 ng/m³. At Hartford High, a room hit 1,000 ng/m³ and was taken out of use. But the majority of schools affected statewide show readings between 100–300 — well within the EPA’s acceptable range.

A review of school PCB data conducted for this article found that over 85% of Vermont schools flagged for action would not have required any remediation under EPA standards.

That discrepancy has caught the attention of budget-minded lawmakers like Senator Terry Williams, who has questioned whether Vermont is applying sound science or simply writing blank checks for hypothetical health scares.

“I still question why the PCB contamination standard for Vermont is twice as high as the EPA’s,” Williams noted in a 2025 budget letter. In fact, Vermont’s limits are not just double — but three to six times more stringent, depending on the age group.

A Real Concern for Staff — Not Just Students

One valid concern that does merit attention is exposure among teachers and full-time staff. Unlike students, who rotate through multiple rooms a day, teachers may remain in a single classroom for six to eight hours a day, five days a week, nine months out of the year — and do so for years. In spaces like Burlington’s Building F — where PCB levels exceeded 6,000 ng/m³ — that could result in significantly higher cumulative exposure.

Still, even in these scenarios, the primary health risks linked to PCBs have historically come through ingestion, not inhalation. While long-term, high-level airborne exposure is increasingly recognized as a concern, the science is still developing, and there is no clear evidence of adverse health effects at the levels recorded in most Vermont schools.

For deeper toxicological profiles, the ATSDR (a division of the CDC) maintains a full report on PCBs’ known impacts and exposure pathways.

The Bottom Line

No one is saying PCBs aren’t hazardous. But Vermont’s air standards are so far below federal recommendations that they’ve triggered expensive, sometimes disruptive interventions for risks that even the EPA doesn’t categorize as urgent.

Vermont may be trying to lead the nation on school safety — but as the science stands today, it may be leading from emotion, not evidence.