Can I refuse an involuntary re-deployment to a hospital position as a non-clinical employee?

Hello -
I am a Medical coder that lives & works in Arizona. I have been working from home since well before the start of the COVID 19 pandemic. My large healthcare employer is asking for corporate employees (non-clinical) to voluntarily apply to be re-deployed to work at the hospital in a non-clinical roll. If needed, this will not be voluntary, it will be required. I have no desire to expose myself to COVID 19 and am considered high risk based on the CDC definition (long time ex-cigarette smoker, overweight, childhood asthma). I do not have a primary care provider that can furnish me with written documentation of this. The HR department does have my previous employer sponsored health insurance attestation saying that I was a smoker until my application in November of this year, as I had quit. Also, I do not have a car (having private transportation has never been required for my job) and getting on public transportation during the pandemic puts me at additional risk. What are my options regarding declining this redeployment if I should be asked?
Thank you