Health & Environment Active Updated Aug 29, 2026
The Upper East Side Legionnaires' cluster
A Legionnaires' disease cluster emerged in Carnegie Hill and Yorkville on the Upper East Side in early July 2026, reaching 10 confirmed cases by Friday night. City health officials ordered testing of every cooling tower in ZIP codes 10028 and 10128 as investigators search for the source, against the backdrop of a 2025 Harlem outbreak that killed 7 people and hospitalized 90 after a hospital ignored its own maintenance plan.
The story so far
-
Aug 29, 2026 Latest
City health officials confirmed two more deaths in the Upper East Side Legionnaires' outbreak, bringing the toll to 11 and making it the deadliest cluster since a 2015 Bronx outbreak that killed 17, four weeks after the city had declared the cluster closed. Dr. Alister Martin said there was no evidence of ongoing transmission since the last diagnosis more than six weeks earlier, and only 1,580 of the city's roughly 4,900 cooling towers had been inspected in the first half of 2026.
Gothamist 
-
Aug 24, 2026
Gothamist reported the health department had filled just 35 of 56 open inspector posts by the outbreak's start and that about half the cooling towers in the three affected ZIP codes had gone a year or more without inspection, as survivors including Ken Pearl blamed the staffing gap rather than just building owners. More than 75 towers in the neighborhood, including at the Guggenheim and the Met, tested positive for the bacteria, and the city has collected $71,000 in fines since May.
-
Aug 15, 2026
Two more people died in the Upper East Side Legionnaires' outbreak, city health officials confirmed Friday, pushing the toll to nine and surpassing last year's Harlem outbreak's seven deaths. Officials said the contaminated cooling tower has already been eliminated but had not confirmed which tower caused the outbreak, with 92 people diagnosed since early July and one patient still hospitalized.
Gothamist -
Aug 8, 2026
The New York Hotel & Gaming Trades Council filed a health department complaint after a cooling tower at the High Line Hotel in Chelsea tested at 170 colony-forming units of Legionella per milliliter, above the city's 10 cfu/mL disinfection threshold, with a July 23 retest coming back at 700 cfu/mL, Gothamist reported. The health department confirmed it is investigating the four-star hotel, a week after the city declared the Upper East Side Legionnaires' outbreak over.
-
Aug 1, 2026
City health officials declared the Upper East Side Legionnaires' outbreak over after a seventh death and 92 confirmed cases since July 2, saying the likely single-cooling-tower source has been eliminated and no new cases have been diagnosed since mid-July.
Gothamist 
-
Jul 31, 2026
A seventh person died in the Upper East Side Legionnaires' outbreak, which has sickened 92 people since July 2, the same week East Village tenants at Haven Plaza, whose water system also tested positive for Legionella, saw remediation begin more than two and a half months after the city's initial order.
-
Jul 29, 2026
A sixth person died in the Upper East Side Legionnaires' outbreak, which has sickened 89 people and hospitalized 71 since July 2, though health officials said no new cases have been diagnosed since July 17 and believe the source, likely a single cooling tower, has been eliminated.
-
Jul 28, 2026
A fifth person died and confirmed cases reached 89 in the Upper East Side Legionnaires' outbreak, with 71 hospitalized. City tests found live Legionella in 56 cooling towers, but only 52% of those towers had been inspected on schedule despite a city law requiring annual checks.
-
Jul 24, 2026
A fifth person died in the Upper East Side Legionnaires' outbreak with confirmed cases reaching 84, and The City Reporter found four of the buildings that tested positive for live Legionella, including one tied to Asphalt Green and one tied to the Cooper Hewitt museum, had no record of complying with the city's monthly cooling-tower testing law. Fifty of more than 180 towers checked in the affected ZIP codes came back positive, while the Health Department has filled only 35 of 56 approved water-ecologist jobs.
-
Jul 22, 2026
A fifth person died in the Upper East Side Legionnaires' outbreak, bringing confirmed cases to 82 with 8 people still hospitalized, and confirmatory testing found live Legionella in 34 cooling towers at 33 buildings with results pending on 140 more. City Council Speaker Julie Menin called the health department's response insufficient, scheduled a September oversight hearing, and unveiled a bill for a Legionnaires' hotline and proactive cooling-tower disinfection.
-
Jul 21, 2026
A fourth person died in the Upper East Side Legionnaires' outbreak as confirmed cases reached 74 across ZIP codes 10028, 10075 and 10128, city Health Commissioner Alister Martin said. Only 35 of the health department's 56 approved water ecologist positions are filled despite a $13 million hiring push meant to add 23 more, and Council Speaker Julie Menin said she would introduce a bill requiring the city to proactively hunt down and disinfect untested cooling towers.
Gothamist -
Jul 20, 2026
A third person died in the Upper East Side Legionnaires' outbreak, city Health Commissioner Dr. Alister Martin announced, with confirmed cases reaching 74 across ZIP codes 10028, 10075 and 10128. Eight people remained hospitalized and 51 had been discharged, and investigators said they had seen no new symptoms in more than a week, a sign the cooling tower disinfection eliminated the source.
-
Jul 19, 2026
A second person died in the Upper East Side Legionnaires' cluster, NYC Health Commissioner Alister Martin announced, as confirmed cases reached 72 with 9 people still hospitalized. The city said all 76 cooling towers that tested positive for Legionella have been disinfected and that its testing and enforcement strategy appears to have stopped the source of exposure.
-
Jul 18, 2026
The Upper East Side Legionnaires' outbreak claimed its first death, city Health Commissioner Alister Martin announced Friday, as confirmed cases climbed to 67 with 12 people hospitalized. The city has disinfected 76 cooling towers across Carnegie Hill and Yorkville that tested positive for Legionella, including towers atop the Metropolitan Museum of Art and the Guggenheim.
-
Jul 16, 2026
The outbreak held at 63 confirmed cases as of Tuesday night with 12 people hospitalized and no deaths, as the city expanded testing to 183 cooling towers citywide, 31 of which came back positive for Legionella.
-
Jul 15, 2026
The outbreak grew to 63 confirmed cases with 52 hospitalized and no deaths, and city health officials ordered 76 buildings, including the Met Museum and Chapin School, to disinfect Legionella-positive cooling towers. The City Reporter found 560 Manhattan cooling towers, including nine at buildings that tested positive, have never submitted required Legionella tests.
-
Jul 14, 2026
City health officials put the Upper East Side Legionnaires' outbreak at 60 confirmed cases as of Sunday night, 15 hospitalized and no deaths, across ZIP codes 10028, 10128 and 10075. All 31 flagged buildings, including the Guggenheim Museum, have had their cooling towers disinfected. Mayor Mamdani said a separate Legionella finding in the Ardsley co-op's hot-water plumbing on the Upper West Side is unconnected, since that building has no cooling tower.
-
Jul 13, 2026
City health officials put the outbreak at 56 confirmed cases as of Saturday, with 16 hospitalized and no deaths. Owners of The Ardsley co-op at 320 Central Park West on the Upper West Side independently tested their hot water system and found Legionella, though health officials said the two situations are unconnected. The city had flagged 31 buildings, including the Guggenheim Museum and a Whole Foods, whose cooling towers preliminarily tested positive.
-
Jul 12, 2026
City Council Speaker Julie Menin said only 13.65% of registered NYC building owners have filed the Legionella tests required since the tightened cooling-tower law took effect May 8, calling the noncompliance inexcusable. Building owners who skip the required monthly tests face fines of $2,000 to $4,000.
-
Jul 11, 2026
City health officials said the Guggenheim Museum is among 31 of 183 tested Upper East Side cooling towers that came back positive for Legionella, giving investigators their clearest signal yet of where the cluster lives. The Guggenheim and 18 other positive sites have already disinfected their towers, with the rest facing a Saturday deadline; the cluster has sickened 46 people and hospitalized 22 across three ZIP codes with no deaths reported.
-
Jul 10, 2026
Mayor Mamdani said the city will publish the addresses of every Upper East Side building whose cooling tower tests positive for Legionella, calling it an unprecedented disclosure step. The cluster held at 36 confirmed cases and 22 hospitalizations, with 139 of 160 registered cooling towers tested and the source still unidentified.
-
Jul 9, 2026
The Upper East Side cluster reached 36 confirmed cases and 22 hospitalizations, with city officials having tested 139 of 160 cooling towers in the three affected ZIP codes without identifying the source building. Council Speaker Julie Menin sent a formal letter to Health Commissioner Dr. Alister Martin demanding an emergency order requiring every building owner in the area to proactively disinfect their cooling tower rather than wait for a positive test result; the health department said the request was under review.
-
Jul 8, 2026
The Upper East Side cluster reached 23 confirmed cases and 17 hospitalizations, with city officials having tested 139 of 160 cooling towers in the three affected ZIP codes without identifying the source building. Mayor Mamdani pledged to publicly disclose any building that tests positive for Legionella.
-
Jul 7, 2026
The cluster grew from 14 confirmed cases Sunday to 18 by Monday, with at least some patients hospitalized in critical condition. Health officials reported testing one-third of all cooling towers in the three affected ZIP codes without identifying the source building. The New York Post reported the number had since exceeded 20.
Politics | Spectrum News NY1 
-
Jul 6, 2026
The cluster grew from 10 confirmed cases on Friday to 14 by Sunday, now spanning three ZIP codes: 10028, 10128, and 10075. NYC Health Commissioner Dr. Alister Martin said every cooling tower in all three ZIP codes was being tested but the contaminated source had not been identified as of Sunday. No deaths have been reported from this cluster.
-
Jul 5, 2026
A Legionnaires' disease cluster grew from 2 confirmed cases Thursday to 10 by Friday night, all concentrated in Carnegie Hill and Yorkville. NYC Health Commissioner Dr. Alister Martin said every cooling tower in ZIP codes 10028 and 10128 is being tested; officials said tap water, showers, and air conditioners are safe, and that the bacteria spreads through mist from cooling towers, not between people. Anyone who visited the area since late June was advised to watch for fever, chills, cough, and muscle aches.
Healthbeat 
Hyperallergic 
6sqft Follow this story as it moves.
The brief follows it every morning: when this storyline moves, the timeline above grows the same day. One short read, free, with the rest of New York explained alongside.
Free, every morning. Unsubscribe in one click.