In Canada, you may be fired for this reason, however you must be paid termination and severance pay in accordance with provincial and common law. If you're a union member, your contract will prevail.
If you want more information, please answer the following questions:
1. Are you a union member?
2. If yes, what does your contract say about this?
3. If no, what is your position?
4. How many years have you worked for this school?
5. How old are you?