CHICAGO (CBS) — It’s back to school in far north suburban Zion, and there will be a lot of new faces, after nearly 50 teachers and staff resigned last week.

In a note on the Zion Elementary School District 6 website, school leaders told parents core classrooms will be fully staffed for the first day of school on Monday.

The district said the resignations of 48 teachers, support staff, and office employees last week are part of the ebb and flow of staffing, and that many are due to personal reasons.

However, former teachers said the district has a tough working environment, some going as far as to call it toxic, and the teachers who resigned couldn’t take it anymore.

“Everything is a struggle,” said retired District 6 teacher Valerie Lampinen. “What I have heard people say, it’s not the students and families, it’s a lack of support from above.”

No current teachers would speak about the resignations on camera.

Meantime, the district has cited a statewide teacher shortage as a reason for its troubles keeping staff, but school officials haven’t said how they filled the open positions after last week’s resignations.