A Legionnaires’ disease outbreak in the South Bronx has killed one person and left four others ill, city health officials announced on Thursday.

The New York City Department of Health and Mental Hygiene said the cluster involves five confirmed cases, including the fatality, and that testing is under way at several nearby buildings.

Investigation launched

Legionella bacteria thrive in warm, stagnant water and can become airborne when mist is generated by cooling towers, humidifiers or decorative fountains. Health inspectors have begun sampling water from cooling towers on rooftops across the neighbourhood, a step they describe as “comprehensive and urgent”.

“We are treating this as a public‑health emergency,” said Dr. Maya Patel, the department’s chief epidemiologist, during a briefing. The department has issued inspection notices to all cooling‑tower owners within a two‑kilometre radius of the identified cases.

Officials issue warnings

Residents have been urged to watch for symptoms such as high fever, chills, cough and shortness of breath, and to seek medical attention promptly if they develop them. The department advises people who work in or live near buildings with cooling towers to keep windows closed when the system is running, and to avoid inhaling visible mist.

“Anyone who thinks they may have been exposed should contact their health‑care provider without delay,” Dr. Patel added. The city has also set up a dedicated hotline for the public to report concerns about water systems.

Broader public‑health concerns

This is the latest in a series of Legionnaires’ incidents in New York City. A separate outbreak in Manhattan earlier this summer resulted in several deaths and prompted a citywide review of water‑system maintenance protocols. The new cluster arrives only weeks after those measures were announced, underscoring the challenge of monitoring thousands of private and commercial towers in a dense urban environment.

Legionnaires’ disease, a form of pneumonia, is not contagious between people but can be fatal, especially for older adults, smokers and those with weakened immune systems. The World Health Organization estimates that about 10 % of reported cases are fatal worldwide.

City officials say the investigation will continue for at least two weeks, after which a full report on the source and remediation steps will be released. A list of inspected cooling‑tower owners is slated for publication early next week, allowing residents to verify compliance.