Norwich — Representatives of the The William W. Backus Hospital and the registered nurses union are scheduled to begin negotiations Wednesday toward a first-ever contract agreement.

A majority of nurses voted in May to form the union, which represents the largest employee group in the hospital. It was the second union to form at the hospital, after security guards and other support staff formed the first union last year. A tentative contract agreement with the guards’ union was reached Thursday.

Backus spokesman Shawn Mawhiney said Monday that the hospital is looking forward to beginning negotiations with the nurses.

On July 21, the union representing the nurses, AFT Connecticut, filed unfair labor practice charges with the National Labor Relations Board. It alleges that the hospital is withholding employee data information relevant to contract negotiations. It also faulted the hospital for denying its request to conduct the negotiation session in a conference room at the hospital, so that nurses could more easily attend before or after their shifts.  Instead, the session will take place at the Norwich Holiday Inn.

Mawhiney declined to comment on the session location.