FORT MYERS, Florida (AP) — Almost three weeks after Hurricane Ian made landfall in southwest Florida, students in the area’s largest school district were poised to return to class.

The School District of Lee County said 28 schools were reopening on Monday and Tuesday, and another 32 have been cleared to reopen soon. The district has almost 120 schools.

Staff at the reopening schools were being invited to catch up on lesson planning on Monday, with students returning Tuesday to reunite with their classmates and classes resuming on Wednesday.

Students at schools that were damaged or that haven’t been cleared are being sent to other schools for the time being.

Superintendent Christopher Bernier said the biggest obstacle to reopening schools has been air quality tests.

“Samples have been sent to the lab for every school that is able to open and we are awaiting the results,” Bernier said in a video message. “Just like you, I want those results back as soon as possible, but I also will not decide to open a school until we have documented that the air inside is safe.”

With more than 100 fatalities, Ian was the third-deadliest storm to hit the US mainland this century behind Hurricane Katrina, which left about 1,400 people dead, and Hurricane Sandy, which killed 233 despite weakening to a tropical storm just before landfall.