When the school action levels were released in November, state officials said schools should take action to "identify and abate" potential PCB sources inside their buildings if tests show a concentration of 100 nanograms per cubic meter of air in buildings used by grade 7 to adult; 60 nanograms per cubic meter for kindergarten to grade 6; and 30 nanograms per cubic meter for prekindergarten.

But the just-released guidance provides more specific direction for what schools will be required to do if airborne PCBs are detected.

Under the new guidance, if rooms have PCB levels above the immediate action levels, they can no longer be occupied. If rooms are above the school action level but below the immediate action level, schools have some options.

In the lowest-risk scenario, schools would only use rooms that tested below the school action levels. For the rooms that tested higher than the school action levels, schools would be required to identify the source of PCBs and take action to reduce the levels within one year, following a consultant's recommendations.

In the higher-risk scenarios, schools could continue using the rooms that tested higher than the school action levels but, within six weeks, must do a more surface-level mitigation — such as installing additional air handling equipment or painting over some of the PCB sources to reduce vapors, Coppolino said. Either scenario would require follow-up testing to determine whether the problem had been addressed.

The state expects to test between 300 to 400 schools as part of the first such initiative in the country.

Coppolino said testing will begin this spring and take more than two years to complete. Because of the size of the project, the state has contracted with six environmental consulting firms — five in Vermont and one in New Hampshire — to carry out the work. The state will prioritize testing schools with younger students and ones built during "the heyday of PCB use," between the late 1950s and 1975, Coppolino said.

Consultants will first do an inventory of each school to determine all of the potential building materials that may contain PCBs. Before being banned by the EPA in 1979,  the chemicals were often contained in window caulk, tile adhesive and lighting ballasts.

Coppolino estimates that around 30 percent of rooms in each school will be sampled, depending on what the inventory finds. A pump with a filter must run for 24 hours in each room being tested, Coppolino said, though students can be in school when the testing is underway. Based on the findings, the consultant will provide a report to each school with next steps.

It's unclear what the new guidance means for Burlington High School. Since last March, students have been learning in a temporary downtown high school, the site of a former Macy's department store. District officials have decided to forgo $70 million in renovations and instead want to build a new high school.
Planning is currently underway, and the district is expected to put a bond for the project to voters in November. School officials have defended the decision to build anew, saying PCBs are widespread in building materials as well as the air, and that the district is in dire need of a fresh start.

"It's hard to look back and see what could have been done differently [in Burlington] if we [had] current practices in place," Coppolino said.

She said the DEC and Burlington school administrators recently discussed whether the new guidance would allow the reopening of administrative offices in the high school's Building A. The school district has not asked about using other parts of the building, Coppolino said, but if it did, she said the DEC would work with them to see what was possible.

As for other schools in Vermont, Coppolino said it's unclear how widespread PCB contamination might be. The only data the state has on PCBs in schools is testing results from Burlington High School and a 2013 pilot study in which four schools in the state were tested for the airborne chemicals. None of those schools showed alarming PCB levels.

One source of potential concern is old fluorescent light ballasts, a common source of PCBs. Lighting ballasts were the main source of widespread PCB contamination at Sky Valley Education Center in Monroe, Wash., where a jury recently awarded $247 million to students, parents and teachers who suffered severe health effects from exposure to the chemicals.

In the mid-1990s, Vermont conducted a light ballast changeout program that many schools participated in, Coppolino said, but there are still some school buildings with old light ballasts. Furthermore, some schools may have taken out fluorescent lights, but not the capacitors in the light fixtures, which are actually the source of PCBs, Coppolino said.

"I don't know," Coppolino said when asked what the upcoming testing might find. "I hate to say one way or another what might happen."