NYC Health Department Releases Preliminary List of Buildings Ordered To Clean and Disinfect Their Cooling Towers in Upper East Side Legionnaires Disease Community Cluster
Preliminary List Includes 31 Buildings and Will Be Updated as Additional Testing and Investigation Continue
All 31 Buildings Have Been Ordered to Immediately Clean and Disinfect Their Cooling Towers, 19 have Completed Remediation, and 12 Are Expected to Be Completed by Tomorrow
It Remains Safe to Shower, Drink Tap Water and Use Air Conditioners in the Affected Zip Codes
July 10, 2026 — The NYC Health Department today released, for the first time, a preliminary list of 31 buildings with cooling towers that tested positive for the presence of Legionella bacteria during an initial PCR (polymerase chain reaction) screening test as part of the ongoing investigation into an Upper East Side Legionnaires’ disease community cluster.
The list is being released to provide New Yorkers with timely information while the investigation continues. Every building identified has been ordered to clean and disinfect its cooling tower immediately out of an abundance of caution, and remediation is expected to be completed for all buildings on the list by tomorrow, July 11. Additional PCR testing results will be available over the weekend and more buildings may be added to the list.
A positive PCR test result does not confirm that a building is the source of the outbreak. PCR testing detects the presence of Legionella bacteria but cannot determine whether the bacteria are alive or dead. Only live Legionella bacteria can cause illness.
To determine whether live Legionella bacteria were present when the samples were collected, the NYC Health Department is conducting culture testing on every cooling tower sampled. Those results take up to two weeks and will help investigators determine whether any of the cooling towers had live Legionella growing at the time the sample was taken. Following new emergency measures announced in response to this community cluster, the Mamdani administration is requiring owners of buildings whose cooling towers have received a positive PCR screening result to clean and disinfect those cooling towers immediately, rather than waiting for confirmatory culture test results.
Because PCR testing cannot distinguish between live and dead Legionella bacteria, not every building that receives a positive screening result will ultimately be found to have live bacteria. But where live bacteria are present, immediate remediation can eliminate the risk of additional exposure while testing continues.
Cooling towers, which release water mist in the outside air, have been identified as the source of previous Legionnaires’ disease community clusters.
A Faster, More Transparent Response
Mayor Mamdani has directed City agencies to respond to this community cluster with urgency and transparency. For the first time, the administration is:
- Releasing the addresses of buildings whose cooling towers tested positive during initial PCR screening.
- Requiring immediate cleaning and disinfection of all cooling towers that receive a positive PCR screening result.
As part of this investigation, the Mamdani administration is requiring building owners to perform a full cleaning and disinfection immediately after a positive PCR screening test, a more aggressive strategy than requiring a boost of chemical disinfectant levels while awaiting a culture testing confirms the presence of live Legionella bacteria, a process that takes two weeks, to conduct a full cleaning.
In addition, under the Mamdani administration, the NYC Health Department has expanded capacity to respond to Legionnaires’ disease clusters by increasing community outreach, inspections, disease surveillance, and laboratory testing.
The Current Investigation
On July 2, the NYC Health Department identified two confirmed Legionnaires’ disease cases in close proximity and immediately launched an investigation in the Upper East Side neighborhoods of Carnegie Hill and Yorkville, including ZIP codes 10028 and 10128. The NYC Health Department’s investigation into the cooling towers in the area began immediately with over 100 staff working over the the Fourth of July weekend.
On July 5, the Department expanded the investigation to include ZIP code 10075 after confirming an additional case involving a person who lives, works, or has visited that area.
As of July 9, 46 people have been diagnosed with Legionnaires’ disease in connection with this cluster. Twenty-two remain hospitalized, 19 have been discharged and are now recovering at home, and five were not hospitalized. There have been no deaths associated with this cluster.
Because symptoms can develop up to 14 days after exposure, the NYC Health Department expects additional cases may be identified for two weeks after the source of exposure has been eliminated.
As part of its investigation, the NYC Health Department has collected water samples from more than 180 cooling towers. As of July 9th, PCR testing found 31 buildings with positive results for the presence of the type of Legionella bacteria that causes Legionnaires’ disease. PCR testing is ongoing at the Public Health Laboratory and additional buildings may be added to this list in the coming days. Because PCR testing cannot distinguish between live and dead bacteria, these results do not confirm that the buildings are the source of exposure. Additional samples may be collected as the investigation continues.
The buildings with positive initial PCR screening results are located at:
- Full Remediation Complete
- 180 East End Ave.
- 1750 York Ave.
- 1660 Second Ave
- 1438 Third Ave.
- 1511 Third Ave.
- 1551 Third Ave.
- 1071 Fifth Ave.
- 1080 Fifth Ave.
- 1001 Fifth Ave.
- 240 E. 82nd St.
- 8 E. 83rd St.
- 145 E. 84th St.
- 117 E. 85th St.
- 125 E. 87th St.
- 152 E. 87th St.
- 120 E. 87th St.
- 501 E. 87th St.
- 168 E. 88th St.
- 160 E. 88th St.
- Cleaning Pending: Ordered to remediate by 7/11/26
- 1875 Second Ave.
- 1110 Fifth Ave.
- 153 E. 78th St.
- 135 E. 79th St.
- 300 E. 79th St.
- 238 E. 81ST St.
- 160 E. 84th St.
- 114 E. 85th St.
- 401 E. 88th St.
- 333 E. 91st St.
- 354 E. 91st St.
- 312 E. 95th St.
Each of these buildings has been ordered to clean and disinfect its cooling tower immediately out of an abundance of caution, even though further testing may determine that live Legionella bacteria present were not present. Acting immediately reduces any potential risk while investigators await culture test results.
It remains safe to use air conditioners and cooling centers in the affected ZIP codes. It is also safe to shower and drink tap water. There is no additional risk being inside one of these buildings.
The NYC Health Department expects full compliance from building owners, consistent with previous Legionnaires’ disease cluster investigations. /p>
About Legionnaires’ Disease
Legionnaires’ disease is a serious form of pneumonia caused by Legionella bacteria, which naturally occur in water. Most people exposed to the bacteria do not become sick. People develop Legionnaires’ disease by breathing in small droplets of water containing live Legionella bacteria. The disease is not spread person to person. Symptoms typically develop two to fourteen days after exposure and include fever, chills, muscle aches, shortness of breath, and cough. Legionnaires’ disease can be effectively treated with antibiotics when diagnosed early.
Anyone who lives, works or has visited the affected area since late June and develops flu-like symptoms should contact a health care provider immediately.
Masks are not recommended because Legionnaires’ disease is not transmitted from person to person, and there is no evidence that masking prevents exposure. People at an increased risk include adults age 50 and older, people who smoke or vape, those with chronic lung disease, people with weakened immune systems and those taking medication that suppresses the immune system.
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MEDIA CONTACT: PressOffice@health.nyc.gov