Can he deny her?!?

Alright, so my place of work is a public place. My employer is trying to tell me that soon my service will not be allowed with me. She is not an emotional support animal, she is a service dog. She performs tasks and aids me. He said unless she is like a seeing eye dog that I won’t be allowed to have her. They have had been hearing issues about a “service dog” biting someone and another potties in the building. That is not a properly trained service dog. They have to have serious training to be a service dog and not just an emotional support animal. He can’t legally do this can he? I am almost positive it’s illegal. He can ban a specific dog if it acts out and does something wrong which mine has not, but he can’t ban all service dogs can he?