Registered nurses at three Prince George's health facilities, unhappy over wages they say compare unfavorably with wages in other Washington jursidictions, have voted through their union to strike in 10 days if they cannot reach a new contract agreement with the county.

In a letter to federal mediators yesterday, the Prince George's Staff Nurse Chapter of the Maryland Nurses Association set a strike date of Aug. 26.

The bargaining unit represents about 650 staff nurses who work at Prince George's General Hospital, Laurel-Beltsville Hospital and the Bowie Health Center.

Chapter president Carolyn Larkin said 91 percent of more than 300 nurses approved the action over the weekend.

If the nurses strike, it will be the first time any members of the Maryland Nurses Association have done so, Larkin said. Last winter, an independent nurses union from Physicians' Memorial Hospital in La Plata walked out for 90 days.

Negotiations for the Prince George's nurses began in February and as the July 1 deadline approached, the union moved the deadline to Aug. 15. The nurses are asking for an 11.5 percent pay increase. Currently, nurses at the three facilities earn salaries ranging from $17,300 to $23,300 annually.

A beginning nurse makes an hourly wage of $8.36, Larkin said, compared with $9 or more an hour in other jurisdictions.

Other contract issues include additional educational benefits and an agency shop in which all staff nurses must pay dues whether or not they belong to the union.

Larkin said the nurses are also concerned that they spend too much time doing odd jobs. "If anything is left undone it's assumed that the nurses will do it," she said.

The nonprofit organization that recently assumed management of the three county health facilities has offered an 8 percent pay increase to beginning nurses, and less to more experienced nurses, according to Kenneth Duncan, vice president and chief operating officer of Community Hospital and Health Care Systems Inc.

Duncan also pointed out that police and firefighters in Prince George's did not get cost-of-living increases this year, and that if the nurses were still county employes as they were until the corporation assumed control July 1, "they . . . would have gotten nothing."

He added, "I think we have been very responsive."