Can an Employer Ask for Proof of Vaccination?
Employers have a duty of care under the Occupational Safety and Health Act of 1970 (OSHA) to provide a safe workplace for employees. To fulfill the duty of care, an employer can ask for proof of vaccination against COVID-19 subject to the EEOC guidelines discussed above and state legislation. If an employee is unable or unwilling to provide proof of vaccination, the employer may be entitled to enforce workplace safety policies such as mask wearing or social distancing.
https://www.hipaajournal.com/is-it-a-hipaa-violation-to-ask-for-proof-of-vaccine-status/
ENJOY YOUR MASK if you're lucky enough that that's what they ALLOW you to do, instead of letting you go.