Growing Outbreak on UES: 59 Now Infected by Legionnaires’ Disease

A Legionnaires’ outbreak tearing through the Upper East Side has now reached 59 total cases as of July 12, with 15 people hospitalized and 31 buildings testing positive for the disease.

No deaths have occurred, and all of the buildings have since reportedly been treated and cleaned.

NYC Health Department officials have told people living in or visiting three ZIP codes—10028, 10128, and 10075—to monitor for symptoms, such as a cough or a fever; this affected area roughly translates to a swath of the neighborhood between E. 74th Street and E. 96th Street, including part of the eastern edge of Central Park.

Legionnaires’ disease, a severe form of pneumonia, spreads via water vapor infected with the Legionella bacteria. It is not contagious. It can be deadly for New Yorkers who have chronic lung disease or a history of smoking, however. There is no cure, although early treatment via antibiotics can greatly improve outcomes.

According to the a July 13 bulletin issued by the NYC Health Department, the Guggenheim Museum (located at 1071 Fifth Avenue) is one of the 31 buildings that had tested positive for the disease.

The other local buildings that have received positive PCR tests for Legionella are as follows: 180 East End Avenue, 1750 York Avenue, 1660 Second Avenue, 1875 Second Avenue, 1438 Third Avenue, 1110 Fifth Avenue, 1511 Third Avenue, 1551 Third Avenue, 1001 Fifth Avenue, 1080 Fifth Avenue, 153 E 78th Street, 135 E 79th Street, 300 E 79th Street, 238 E 81st Street, 240 E 82nd Street, 8 E 83rd Street, 145 E 84th Street, 160 E 84th Street, 114 E 85th Street, 117 E 85th Street, 120 E 87th Street, 125 E 87th Street, 152 E 87th Street, 501 E 87th Street, 160 E 88th Street, 168 E 88th Street, 401 E 88th Street, 333 E 91st Street, 354 E 91st Street, and 312 E 95th Street.

Pinpointing the exact origin of the outbreak will take more extensive testing and time, officials say, with the preliminary PCR test results stemming from widespread inspections of local cooling towers that sit on top of the buildings.

The warm basins of the towers, which release waste heat, serve as fertile breeding grounds for Legionella. Building owners are mandated to flush the cooling towers they oversee of the bacteria on a regular basis, a process that involves treatment with biocides such as chlorine and the maintenance of lower water temperatures.

In the wake of a deadly Legionnaires’ outbreak that killed seven people in Harlem last summer, the New York City Council passed a law strengthening testing requirements for the disease, which took effect on May 8 of this year. According to a report in Gothamist, seven of the ten buildings later tied to the outbreak had not been tested in over a year.

Yet with the disease now plaguing the Upper East Side, new reporting from the same outlet has unveiled that 20 percent of building owners did not submit Legionnaires’ testing results to the city in the first five months of 2026, despite improved staffing levels.

While the Health Department has said that testing will ramp up significantly in the future as the law gains steam, City Council Speaker Julie Menin—who represents the Upper East Side—has pressed officials on the progress of testing and tracing when it comes to the current outbreak striking her district.

“We want to make sure that people have the necessary information,” she said at a virtual town hall on the subject, which was held on July 6. She also attended an in-person town hall the next day at a church on Park Place.

Meanwhile, the bacteria has been detected in the hot water system at a building on the Upper West Side, located at 320 Central Park West. The building’s owners have tested the water system independently, and have told residents that they are taking steps to eliminate the bacteria in the coming days.