After 17 months of negotiating, teachers in West Chicago went on strike Monday morning, cancelling class for more than 4,000 students.

The main sticking points between the teachers union and officials in the West Chicago Elementary School District 33 has been salaries and health insurance premiums. School officials say budgetary restrictions will force them to place a cap on health insurance costs.

Two care centers will remain open for students who have registered, according to a message posted on the district’s website.

The district employs 282 certified staff members and oversees six elementary schools, a preschool and a middle school.