# Legionella outbreaks linked to cooling towers

> Live situation record from CLSTR: https://clstr.news/situations/legionella-outbreaks-linked-to-cooling-towers
> Updated: 2026-08-14T20:41:37.000Z. Sources: 38. Developments: 3.

In New York City, a Legionnaires’ disease outbreak centered in the Carnegie Hill and Yorkville neighborhoods of the Upper East Side has concluded. While the outbreak was officially declared over on July 31 following a period with no new diagnoses, the final death toll reached nine people. The investigation, which covered 183 cooling towers across 160 buildings, confirmed that 59 towers contained live bacteria. Although officials stated, “We are confident the source of the Legionella bacteria has been eliminated,” the investigation highlighted widespread compliance issues. In total, the Manhattan cluster resulted in 92 diagnosed cases.

In Basel, Switzerland, an outbreak linked to a water-cooled cooling tower on Rebgasse in the Kleinbasel district resulted in 26 infections and one fatality. Seven patients required intensive care. Testing of ten nearby towers found eight exceeded legal limits, with two towers on the same office building roof showing particularly high bacterial counts. Implicated units have been shut down for decontamination, and authorities continue to inspect urban cooling-tower installations while advising anyone with respiratory symptoms to seek medical attention.

## Claims

- 26 people were infected with Legionnaires' disease in Basel. (corroborated by 20 sources)
- One person died from the Legionella outbreak. (corroborated by 20 sources)
- 25 of the infected patients were hospitalized. (corroborated by 13 sources)
- The outbreak source is a water‑cooled cooling tower on Rebgasse in Kleinbasel. (corroborated by 12 sources)
- The cooling tower has been shut down. (corroborated by 12 sources)
- Legionella bacteria spread through aerosolised water droplets emitted by the cooling tower. (corroborated by 12 sources)
- Seven patients required intensive‑care treatment. (corroborated by 8 sources)
- Authorities are testing other cooling towers and have found Legionella above safety limits in several of them. (corroborated by 8 sources)

## Timeline

### 2026-08-14: Upper East Side Legionnaires' outbreak death toll reaches nine

The death toll from the Upper East Side Legionnaires' disease outbreak has reached nine, surpassing a previous cluster in Harlem. The NYC Health Department has declared the outbreak over.

5 sources. https://clstr.news/cluster/upper-east-side-legionnaires-outbreak-death-toll-reaches-nine

### 2026-08-03: Basel cooling‑tower Legionella outbreak sickens 26, kills one

Basel reports 26 Legionella cases, one death; a cooling‑tower on Rebgasse is the suspected source and has been shut down.

27 sources. https://clstr.news/cluster/basel-legionella-outbreak-1-dead-26-sick-linked-to-cooling-tower

### 2026-07-29: New York City Upper East Side Legionnaires Outbreak Claims Sixth Fatality, 90 Cases Confirmed

NYC reports a sixth death in the Upper East Side Legionnaires outbreak, raising confirmed cases to 90; cooling towers have been cleaned and the source deemed eliminated.

8 sources. https://clstr.news/cluster/new-york-city-upper-east-side-legionnaires-outbreak-claims-sixth-fatality-90-cases-confirmed

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Cite as: Legionella outbreaks linked to cooling towers. CLSTR, https://clstr.news/situations/legionella-outbreaks-linked-to-cooling-towers