An elementary school in Hackettstown will remain closed for about four weeks after a fungus issue was discovered inside the building, the school district’s superintendent said Friday.

Willow Grove Elementary School was first closed Thursday in order for health officials to conduct tests. Preliminary tests results revealed high levels of fungi and spores. Officials said a lack of ventilation and high levels of humidity caused the fungus buildup.

Hackettstown School District Superintendent David Mango said that at least 13 classrooms at the elementary school must be cleaned. As a result, Willow Grove students will spend roughly four weeks learning at neighboring schools as their building undergoes a deep clean. 

"We're not playing any games or taking any chances. Even if that means having staff and students report to alternative locations,” Mango said.

On Friday, all students reported to Hackettstown Middle School, but starting Monday, students in kindergarten through fourth-grade and students with special needs will be split up and report to neighboring schools.

The superintendent said this isn't the district’s first time dealing with such a situation. After Superstorm Sandy and an outbreak of the swine flu, the schools in the area worked together to make sure students had a place to go to continue school.

"The Warren County Health Department told me, ‘You're the first school district in 20 years to shut down a school.’ So here we are again three and a half years later,” Mango said.

Some parents said that despite the changes, they appreciate the district’s efforts. 

“I'm really glad that they caught it as fast as they did,” parent Dawn Smith said. “They've got a really good plan in place, and they're taking care of the kids and that's all that matters."

Others, however, questioned why the issue wasn’t discovered over the summer.

“We're so early in the school year, and it would have been great if they had discovered this over the summer,” parent Summer Watkins said.

Mango said that while contingent plans are in place so students don't miss instruction time, he said the next challenge will be funding upgrades to the district’s old buildings.

The superintendent said Willow Grove was built in 1971 and much of the damage from the fungus buildup should be covered by insurance.