City Declares End to Deadly Upper East Side Legionnaires' Outbreak

New York City health officials announced on Friday that the Legionnaires' disease outbreak on the Upper East Side has been contained. Dr. Alister Martin, the city health commissioner, stated that the source of the cluster has been eliminated, and residents or visitors to the area are no longer at an elevated risk of infection.

The declaration follows a difficult period for the neighborhood, which saw 92 confirmed cases of the severe pneumonia-like illness since the cluster was first identified on July 2. According to the city health department, 70 individuals required hospitalization, and five patients remained under medical care as of Friday. The outbreak resulted in seven deaths, matching the toll of a similar incident in Harlem last summer.

Officials noted that the end of the outbreak was determined by a two-week window during which no new symptoms were reported. Because the incubation period for Legionella bacteria can last up to 14 days, the absence of new cases suggests the threat has passed.

The investigation focused on water cooling towers, which are known to harbor the bacteria if not properly maintained. Under city regulations, building owners are required to prevent bacterial growth in these systems. During the investigation, the city inspected roughly half of the 160 cooling towers in the affected ZIP codes—10128, 10028, and 10075—resulting in 110 code violations.

While the city identified Legionella in several buildings, including those operated by the Metropolitan Museum of Art and the Guggenheim, officials are still working to pinpoint the specific tower that served as the primary source of the outbreak. Dr. Martin indicated that the city is continuing in-depth inspections to ensure compliance with maintenance protocols. Two property owners were identified as "bad actors" for failing to properly maintain or register their equipment, with each facing fines of approximately $10,000.