NYC Health Department Confirms Source of South Bronx Legionnaires’ Disease Cluster Is Eliminated, Elevated Risk of Exposure Has Ended

NYC Health Department Confirms Source of South Bronx Legionnaires' Disease Cluster Is Eliminated, Elevated Risk of Exposure Has Ended

No Patients With New Symptoms of Legionnaires' Disease Related to Cluster in More Than Two Weeks, Confirming Exposure Source Was Eliminated

Health Department's Genome Sequencing Investigation Continues With Molecular Analysis of Patient and Cooling Tower Samples Underway

September 30, 2026 - Today, the New York City Health Department announced there is no longer an elevated risk of Legionnaires' disease in the South Bronx neighborhoods of Melrose and Morrisania (ZIP codes 10451, 10455, 10456, and 10459). More than two weeks have passed since anyone who lives in, works in, or visited the area began feeling symptoms of Legionnaires' disease, which can take that long after exposure to present. All cooling towers in the area with a positive test were cleaned over two weeks ago.

This confirms that the source of exposure has been eliminated. This announcement follows the Health Department's aggressive disease investigation and to quick sampling, testing, and cleaning of cooling towers in the area.

"From the moment this cluster was identified, we were on the ground in the South Bronx distributing more than 10,000 flyers, speaking with more than 3,500 community members, and reaching out to approximately 300 community organizations and local businesses," said NYC Health Commissioner Dr. Alister F. Martin. "The increased risk of exposure has ended, and the source has been eliminated, but our work is not over. We will hold accountable any cooling tower operator who fails to follow the rules of this city and jeopardizes the health of New Yorkers. I want to thank our community partners, especially the local elected officials, for their help getting accurate information into the hands of the community."

The Health Department launched a Legionnaires' community cluster investigation in the South Bronx on September 10, sampling 24 cooling towers in the area that same day. Initial screening test results were completed by September 12, prompting the Health Department to order 10 cooling towers to be cleaned and disinfected, and all 10 were cleaned by September 15. On September 23, the Health Department confirmed the presence of live Legionella bacteria in seven cooling towers, each of which had been cleaned the week prior. On September 25, culture test results for all 24 cooling towers confirmed that the only cooling towers with live Legionella bacteria in the area were the seven identified two days earlier.

The Health Department conducted community outreach since the start of the investigation, distributing more than 10,000 palm cards and flyers throughout the area, speaking with more than 3,500 community members, and engaging approximately 300 businesses and organizations in the area.

Hundreds of Health Department staff members supported the response, interviewing and reviewing records for dozens of potential cases, collecting samples from two dozen cooling towers and performing multiple tests on each sample, canvassing the community, hosting a webinar for healthcare providers, holding multiple town halls and public briefings, issuing press releases, and providing daily updates on nyc.gov/legionnaires and social media.

These efforts were supported by community partners and local elected officials who helped canvass their communities, including staff from New York Governor Kathy Hochul's regional office, New York State Senators Luis Sepúlveda and José Serrano, New York State Assembly Members Landon Dais and Chantel Jackson, Bronx Borough President Vanessa Gibson, and New York City Council Members Justin Sanchez and Althea Stevens.

As of September 29, 23 people have tested positive for Legionnaires' disease in association with the South Bronx cluster. Twenty-one people were hospitalized, including two who are currently admitted and 17 who have been discharged, and two who tragically passed away. Two people were never hospitalized. The Health Department continues to work on whole genome sequencing for the source of exposure to the Legionella bacteria associated with this cluster, with molecular analysis underway to match the live bacteria found in samples from cooling towers with the bacteria found in patient samples. Results are expected by late fall.

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