New York City Health Department Provides Update on Community Cluster of Legionnaires' Disease in Central Harlem

Ninety-two cases have been identified in the area; three deaths have occurred

Eleven of the twelve cooling towers have been remediated; the final tower is required to be completed by August 15

August 14, 2025 — Today, the New York City Health Department provided an update on the investigation into a community cluster of Legionnaires’ disease in Central Harlem (ZIP codes 10027, 10030, 10035, 10037, and 10039). Ninety-two people have been diagnosed with Legionnaires’ disease since July 25 when the cluster was first identified. Three people have died, and 15 people are currently hospitalized. The NYC Health Department has confirmed that 12 cooling towers have tested culture positive on 10 buildings for live Legionella bacteria. Eleven of the 12 cooling towers have completed remediation. The final cooling tower remediation is required to be completed August 15. These cooling towers are located at:

• BRP Companies, Lafayette Development LLC, 2239 Adam Clayton Powell Jr Blvd Manhattan, NY 10037
• BVK, 215 W 125th St Manhattan, NY 10027
• Commonwealth Local Development, 301 West 124th St, Manhattan, NY 10035
• CUNY – City College Marshak Science Building, 181 Convent Ave, Manhattan, NY 10031
• Harlem Center Condo, 317 Lenox Ave, Manhattan, NY 10030
• NYC Economic Development Corporation, 40 West 137th St, Manhattan, NY 10037
• NYC Health Department Central Harlem Sexual Health Clinic, 2238 5th Ave, Manhattan, NY 10030
• NYC Health + Hospitals/Harlem, 506 Lenox Ave, Manhattan, NY 10037
• The New York Hotel Trades Council Harlem Health Center,133 Morningside Ave, Manhattan, NY 10027
• Wharton Properties, 100 W 125th St Manhattan, NY 10027 (3 of 8 towers)

“Our hearts go out to everyone impacted by this cluster of Legionnaires, in particulate the friends and loved ones of the three New Yorkers we lost to this disease,” said New York City Mayor Eric Adams. “As of today, 11 of the 12 cooling towers in Central Harlem that tested positive for Legionella bacteria have completed remediation, and by tomorrow, all towers will have completed remediations. New Yorkers should know the air is safe to breathe, and we are seeing declining numbers of new cases each day. I want to thank the health workers who worked tirelessly to treat this community and make sure its residents are healthy. We will continue to share updates, and we encourage anyone with flu-like symptoms to seek medical help immediately.”

"As the city’s doctor, I want all New Yorkers to know this Legionnaires’ cluster in Central Harlem is the top priority of the New York City Health Department. We are working with the Mayor’s Office, Central Harlem elected officials, our community partners, and health care providers to ensure New Yorkers are fully informed of this evolving cluster," said Acting Health Commissioner Dr. Michelle Morse. "The good news is that new cases have begun to decline, which indicates that the sources of the bacteria have been contained. Our expert inspectors will continue to work with building owners to ensure full compliance. New Yorkers who live or work in the identified ZIP codes and have flu-like symptoms should contact a health care provider as soon as possible for timely diagnosis and treatment for the best chance at a good outcome.”

New Yorkers who live or work in one of the identified ZIP codes in Central Harlem with flu-like symptoms, cough, fever, or difficulty breathing should seek medical attention immediately. Individuals at higher risk include those ages 50 and above, cigarette smokers, and people with chronic lung disease or compromised immune systems. The risk is not increased for people who live or work in the buildings identified with positive culture tests. The risk is to anyone who spends time in the neighborhood because the bacteria travel outside the buildings into the surrounding area.

The NYC Health Department has required building owners to conduct remediation to all the positive cooling towers, including initial PCR positive towers and confirmed culture positive towers. The NYC Health Department continues to analyze the cooling tower samples to try to identify if any of them were a source.

PCR Positive vs Culture Positive

At the start of the investigation, the NYC Health Department conducts a preliminary rapid PCR test to identify traces of the Legionella bacteria on all cooling towers in the investigation area. These bacteria may be alive or dead. Dead bacteria cannot make people sick. The NYC Health Department directs all towers with initial PCR positive results to remediate within 24 hours by adding or changing chemicals used to kill the bacteria in an effort to cut off the source or sources of the bacteria as fast as possible.

The NYC Health Department’s Public Health Lab also conducts culture testing on all samples collected from all the cooling towers in the investigation area to detect any confirmed Legionella pneumophila growth. Culture testing takes two weeks to grow and is the gold standard as it detects the presence of Legionella bacteria that can cause illness. Where there are positive culture test results, the NYC Health Department requires owners to remediate the cooling tower by fully cleaning and disinfecting the whole cooling tower system.

Determining The Source

The NYC Health Department’s investigation on the source responsible for Legionnaires’ disease in Central Harlem is still underway. Our Public Health Lab experts are comparing the DNA in the cultures grown from the cooling towers to the DNA in the cultures from patients. Molecular analysis of Legionella bacteria from patients and cooling tower specimens will help the NYC Health Department determine a possible match.

For more information, see the NYC Health Department’s Legionnaires’ Disease webpage.

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MEDIA CONTACT: Press Office PressOffice@health.nyc.gov