can i be fired for not signing new polices and procedures if i dont agree

Do you have a contract, whether individually or through a union, that limits the company's right to fire you?  Sometimes such a contract can be implied from an employee handbook.  If not, you can be fired for any reason not prohibited by statute (e.g. race, gender, etc.) certainly including for not agreeing to new company policies, unless perhaps the policy itself was illegal (e.g. if the policy was that you would not sell to non-white customers, you might have a case that  you couldn't be fired for not agreeing to it).