KANEOHE, Hawaii -- The state's largest public worker union plans to file a grievance over conditions at the state mental hospital, KITV has learned.

The news comes as administrators are planning to review safety at the hospital, where employees have complained about brutal assaults by patients in recent months.

Last month, employees came forward to complain that the state hospital is not a safe place for either patients or employees.

Former state hospital nurse Terry Evans suffered facial fractures and bruising after a male patient attacked her in January. It is the worst case of patient violence at the hospital in several years.

Because of that attack and others, the Hawaii Government Employees Association, which represents nurses and doctors at the hospital, confirmed to KITV it plans to file a grievance over safety conditions.

Last week, the hospital administrator set up a performance improvement team that will focus on safety problems here at the hospital. Among their tasks will be cutting down on assaults as well as looking at possible changes in procedures and training.

Dr. Thomas Hester, who heads the Adult Mental Health Division for the state, told KITV he is "encouraged" by what he called the "collaboration and work between hospital administration and clinical staff to work together to improve safety in the hospital."

State Sen. Clayton Hee represents the Kaneohe area, where the hospital is located.

"Better late than never, but let's give the hospital administration the credit due to starting to address these long-standing problems," Hee said.

Hee invited the media to accompany him on a tour of the overcrowded mental facility last month.

The staff showed Hee rusting, 15-year-old vans used to transport patients.

"I'm sure people wouldn't put their own family in the vans, but they would put the mentally ill in the vans. That's not a good message from the state of Hawaii," he said.

The state hospital said it has now purchased about six used vans that are about 5 years old with air conditioning that will replace half the aging van fleet shortly.

Gov. Linda Lingle's senior policy advisor Linda Smith and other top state officials toured the state mental hospital last week to get a look at some of the facilities and the out-dated vans.