NYC Investigates Legionnaires' Outbreak Amid 28 Illnesses

WHO:

ABC7 New York - Mayor Zohran Mamdani stated that the city will soon release the exact addresses of the buildings where legionella bacteria is present in the cooling towers.

ABC News - New York City Department of Health is investigating a cluster of Legionnaires' disease.

ABC7 New York - Mayor Zohran Mamdani is involved in the response to the outbreak.

WHAT:

ABC7 New York - The number of confirmed cases of Legionnaires' disease has increased to 36, with 22 individuals hospitalized.

The Guardian - Health department officials have sampled water from nearly 160 building cooling towers to test for the bacteria.

The Guardian - Dr. Alister Martin, the commissioner of the New York City health department, signed orders for at least 19 buildings to drain, clean, and disinfect cooling towers.

The Guardian - The health department stated it could take another month before findings in the investigation are issued.

ABC7 New York - The number of confirmed cases of Legionnaires' disease has increased to 36, with 22 individuals hospitalized.

The Guardian - Health department officials have sampled water from nearly 160 building cooling towers to test for the bacteria.

The Guardian - Dr. Alister Martin, the commissioner of the New York City health department, signed orders for at least 19 buildings to drain, clean, and disinfect cooling towers.

The Guardian - The health department stated it could take another month before findings in the investigation are issued.

ABC7 New York - The number of confirmed cases of Legionnaires' disease has increased to 36, with 22 individuals hospitalized.

ABC7 New York - The number of confirmed cases of Legionnaires' disease has reached 28, with 21 individuals hospitalized.

ABC7 New York - Health officials warned that the process to determine the actual source of the outbreak could take weeks.

ABC News - 23 cases of Legionnaires' disease have been confirmed in Manhattan's Upper East Side neighborhoods.

ABC7 New York - The number of confirmed cases has risen to 28, with 21 individuals hospitalized.

ABC7 New York - Health officials expect the number of confirmed cases to continue to rise as testing and investigations proceed.

ABC7 New York - The outbreak last summer in Harlem resulted in seven deaths and over 100 infections.

WHERE:

ABC7 New York - The outbreak is linked to three Upper East Side ZIP codes: 10028, 10128, and 10075, which include the neighborhoods of Carnegie Hill, Yorkville, and Lenox Hill.

ABC News - The affected neighborhoods are Carnegie Hill and Yorkville in Manhattan.

ABC7 New York - The outbreak is linked to three Upper East Side ZIP codes: 10028, 10128, and 10075.

WHEN:

ABC News - The health department reported the confirmed cases as of July 6.

ABC7 New York - Testing of cooling towers on the Upper East Side is expected to be completed by the end of the day Wednesday.

ABC7 New York - A list of cooling towers of interest will be released by the end of the week.

WHY:

ABC News - The likely source of the bacteria is believed to be a cooling tower in the area that sprays a mist containing the bacteria.

ABC7 New York - Health officials state that the outbreak is not linked to any building's plumbing system.

HOW:

The Guardian - Epidemiologists need to culture water samples to determine if the Legionella bacterium identified by PCR tests was a live colony and then sequence the genome of those cultures to compare with patient samples.

ABC7 New York - Mark Levine, the city's comptroller, stated, "All cooling towers in [the] area are being sampled and tested in the NYC Public Health Lab," emphasizing that it takes several weeks for cultures to grow.

ABC7 New York - The health department emphasized that the outbreak is not linked to any building's plumbing system, allowing residents to continue using tap water and home air conditioning systems.

ABC News - The bacteria causing Legionnaires' disease are typically spread through inhaling contaminated mists from cooling towers.

ABC7 New York - Cooling towers in the area are being sampled and tested in the NYC Public Health Lab.

(UPDATED July 9, 2026 19:25 UTC)

The number of confirmed cases of Legionnaires' disease in New York has risen to 36, with 22 individuals currently hospitalized. Health department officials have taken proactive measures by sampling water from nearly 160 building cooling towers and have ordered at least 19 buildings to drain, clean, and disinfect these towers. It may take another month for the health department to release findings from their investigation, as epidemiologists work to culture water samples to confirm the presence of live Legionella bacteria and analyze their genetic makeup.

(UPDATED July 9, 2026 17:39 UTC)

The number of confirmed cases of Legionnaires' disease in New York has risen to 36, with 22 individuals currently hospitalized. Health department officials are actively testing water from nearly 160 building cooling towers, and Dr. Alister Martin has ordered at least 19 buildings to drain, clean, and disinfect their cooling systems. It may take another month before the health department releases findings from this investigation, as epidemiologists work to culture water samples and analyze the Legionella bacterium.

(UPDATED July 9, 2026 06:20 UTC)

The number of confirmed cases of Legionnaires' disease has risen to 36, with 22 individuals currently hospitalized. Mark Levine, the city's comptroller, announced that all cooling towers in the area are being sampled and tested at the NYC Public Health Lab, noting that it takes several weeks for cultures to grow. Health officials are closely monitoring the situation as they work to identify the source of the outbreak.

(UPDATED July 9, 2026 02:52 UTC)

Mayor Zohran Mamdani announced that the city will soon disclose the specific addresses of buildings where legionella bacteria has been found in cooling towers, as the number of confirmed cases of Legionnaires' disease has now reached 28, with 21 individuals hospitalized. Health officials have cautioned that identifying the actual source of the outbreak, which is connected to three Upper East Side ZIP codes—10028, 10128, and 10075—could take several weeks. However, the health department reassured residents that the outbreak is not associated with any building's plumbing system, so they can continue using tap water and their home air conditioning systems without concern.

(UPDATED July 9, 2026 01:32 UTC)

The New York City Department of Health is currently investigating a cluster of Legionnaires' disease, with 28 confirmed cases reported in Manhattan's Upper East Side neighborhoods, including Carnegie Hill and Yorkville. Mayor Zohran Mamdani is actively involved in the response, as health officials anticipate that the number of cases will continue to rise, especially with testing of cooling towers expected to be completed by the end of the day Wednesday. The likely source of the outbreak is believed to be a cooling tower in the area, which spreads contaminated mists, and a list of cooling towers of interest will be released by the end of the week.