Students and staff returned to the Penn Kidder Campus on Tuesday after six weeks of air testing, deep cleaning, and ventilation work to remove chemical vapors that spread through the building in late September.

Jim Thorpe Area School District confirmed that the building is now safe following multiple rounds of air-quality testing. The results showed levels of para-dichlorobenzene and naphthalene — two chemicals found in mothballs — are below federal safety limits.

“It’s like the first day of school all over again for the Penn Kidder students,” said Interim Superintendent Tom Lesisko. “It’s been a burden for everybody — for parents, kids, and staff. We’re just so glad to be back.”

The campus closed Sept. 23, when staff members reported the smell of mothballs. District officials later discovered that an employee had placed mothballs in several areas of the building to deter mice. The vapors were drawn into the ventilation system and circulated throughout the school.

An initial round of testing in early October showed five rooms with elevated levels of para-dichlorobenzene above the acceptable limit of 2.2 micrograms per cubic meter.

“Some rooms were very high, some were lower, closer to what we consider safe,” Lesisko said at an Oct. 15 board meeting. “We retested again, and the levels came down, but they were still above where they should be. The highest number was 42 in one room, and that dropped down to 3.7. The results kept showing decreases.”

Four rounds of testing were ultimately completed before the decision to reopen was made.

Lesisko said the district didn’t want to rush the process.

“We were cautious and kept testing until everything looked right,” he said. “The third round showed improvement, and the fourth finally got us to where we needed to be.”

The latest test results, received Friday, confirmed that every room in the building is below the safety threshold.

“We tested 12 different areas on the first floor, including common areas like the library and cafeteria,” Lesisko said. “Every room is down below where it needs to be.”

To help clear the air, the district used 22 industrial blowers equipped with carbon filters to remove lingering chemical vapors.

“The chemical drifts quite a bit, so we had 22 blowers running to move the air and carbon filters to absorb the chemicals,” Lesisko said. “That seemed to be the final step that got the air as clean as it could be.”

In addition to air cleaning, the district performed a thorough cleaning of the facility. “Every hard surface, including the walls, was wiped down,” Lesisko said. “Carpets were vacuumed multiple times to stir up and collect any remaining material so the filters could remove it.”

During the closure, students in kindergarten through fifth grade attended classes at L.B. Morris Elementary, while sixth through eighth graders were temporarily relocated to Jim Thorpe Area High School.

On Monday, students attended a half-day before the move back to Penn Kidder. The afternoon was dedicated to staff returning to prepare classrooms for reopening. “We’re trying to make it like the first day of school,” Lesisko said. “It’s fresh. Our community’s back.”

Teachers began setting up classrooms Monday afternoon.

“They started packing up Friday once we knew things were looking good,” Lesisko said. “Even the laptop and iPad carts were moved back.”

The district also provided guidance for parents about student belongings that were left behind when the building closed. Officials said the cleaning and air recycling process allowed any volatile compounds to dissipate naturally. Students may take their items home and use them as normal. Families who prefer extra precautions can air out, wash, or wipe down belongings before use.

“All textbooks, library books, and school-owned materials have been deemed safe and will remain in use,” the district said in a statement.

While the district does not yet have a final cost estimate, Lesisko said it will likely be substantial.

“Testing was about $1,200 per pod, plus shipping,” he said. “Then there’s additional costs for things like extra busing mileage. There are a lot of little things that add up. It’s going to be a large number, unfortunately.”

The testing was conducted by an environmental consultant, and samples were analyzed at a laboratory in Knoxville, Tennessee.

“Hopefully everybody’s excited,” Lesisko said. “It’s been a long road. But we’re finally home.”