Another case of Legionnaire's disease has been confirmed at the Western Maryland Center state hospital in Hagerstown. That brings to five and possibly six the number of patients who have contracted the pneumonia at the hospital and died since November 1988, authorities said Friday.

The latest case involves a 69-year-old western Maryland man who died May 30, said Mike Golden, a spokesman for the Maryland Department of Health and Mental Hygiene. The patient, whose identity was not disclosed, had been a patient at the hospital since April 24.

Ten cases of Legionnaire's disease have been confirmed at the state-supported hospital since November 1988, Golden said. Five of the patients died and five recovered.

Another nine patients are believed to have contracted Legionnaire's, but tests were inconclusive. One of those nine patients died and the others recovered, Golden said.

The 175-bed medical center for chronic disease and rehabilitation treats patients suffering from cancer, strokes, respiratory diseases, spinal cord injuries and other long-term conditions.

In March, a private laboratory from Georgia was hired to conduct environmental tests at the hospital to search for the source of the Legionella bacteria. Laboratory workers tested water in pipes, tanks, water softeners, shower heads and faucets.

Twenty-four of the 39 water sample tests were positive for Legionnaire's disease bacteria. All the positive results were in the hospital's hot water system, and attention focused on one of two water heaters.

After discovering the probable source, every spigot and shower head in the hospital was flushed with 170-degree water. The bacteria thrives in 100- to 120-degree water, but is killed at 140 degrees or hotter, health officials said.

This week, the hospital flushed the water system with hot water again. Officials also increased the amount of chlorine in the water in hopes of killing any bacteria present in the system, Golden said.