In the wake of three serious patient-on-staff assaults, more than 150 nurses at Washington's Western State Hospital have signed a "no-confidence" letter calling for the replacement of the psychiatric hospital's chief nursing officer Karen Pitman and her deputies.

"We have lost all trust, faith, and confidence in the current Western State Hospital Nursing Administration to advocate for nursing," the letter read.

The letter was delivered by email Friday to Dave Holt, Western State CEO and Cheryl Strange, Secretary of the Department of Social and Health Services.

The letter accuses Pitman, who was appointed in March, and her deputies of violating labor agreements, barring frontline staff from providing input before staffing changes are made and allowing "dangerous mixes" of patients on wards.

"We have had numerous injuries at Western State Hospital ... we are headed in the wrong direction," said Paul Vilja, a nursing supervisor who has worked at the hospital for 34 years and who played a key role in drafting the letter.

In August and September, three nurses at Western State Hospital were seriously injured by patients. Two of the nurses were knocked to the ground and stomped, a third had her earlobe bitten off.

In response to the letter, top officials at Washington's Department of Social and Health Services (DSHS) said Pitman still has their confidence and is making safety a top priority.

"What she is absolutely charged with right now is ensuring that the ward structure includes a culture of safety for everyone on the ward," said Tonik Joseph, deputy assistant secretary of the Behavioral Health Administration at DSHS.

Joseph took exception with some of the allegations contained in the no-confidence letter, including that a ward for high-needs medical patients is being closed and staff transferred "under duress" to new wards in violation of their collective bargaining agreement.

Joseph said that ward -- known as E6 -- is being temporarily closed while it's made more secure and converted to a forensic ward to accommodate the growing number of jail inmates who come to Western State Hospital for competency evaluation and restoration services.

"We are doing some conversion and repurposing of the ward and so we will be back there with patients," she said, adding that the closure had not generated any union grievances.

The state of Washington has accrued more than $50 million in court fines for delays in providing services to mentally ill inmates in county jails.

In their letter, the front line nurses say the closure of E6 is putting strain on other wards that have to absorb the patients. "Patient care was not considered, staff and patients were recklessly endangered," the letter said.

In a statement Friday, Pitman said, "My primary goal is to be the voice of nursing and nursing safety and practice. I want what is best for staff, patients and the hospital."

In June, Western State Hospital failed to meet federal standards resulting in a loss of $53 million a year in funding. That followed a two-year turnaround effort that fell short in several areas, including nursing services.

Western State Hospital is the state's largest psychiatric facility with 857-beds and a nursing staff of approximately 380. SEIU 1199, the union that represents the nurses, was not involved in the drafting of the "no confidence" letter. The number of nurses who signed the letter represent less than half of the nursing staff.