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Recent cases of Legionnaires' disease in Switzerland have identified additional sources of Legionella bacteria. Car washes are now also becoming a focus of occupational and consumer safety measures.
Legionella are bacteria that occur in water of various origins – from drinking water to wastewater. They multiply only slowly below 20 °C and die off completely above 60 °C. Their optimal growth temperature lies between 30 and 50 °C.
Unlike many other germs, Legionella only become problematic when they enter the lungs. This happens when water containing Legionella is finely aerosolized and the droplets are inhaled. Sources of contaminated water can include showers, cooling systems, whirlpools, fountains, as well as car wash facilities and high-pressure cleaners.
Once Legionella enter the lungs, they can cause two types of illness: the milder form, Pontiac fever, presents like a severe flu but usually subsides on its own after a few days. Much more dangerous is Legionnaires’ disease, also known as legionellosis. This is a severe form of pneumonia that is fatal in 5–10% of cases.
After shower systems and cooling towers had already been identified years ago as sources of Legionella infections (including severe pneumonia) and have since been subject to regular monitoring, Legionella infections linked to visiting a car wash facility have now also been identified for the first time.
In the Swiss canton of Zurich, three cases of Legionnaires’ disease were reported in 2018, all traced back to the same car wash facility (source: https://www.blick.ch/life/gesundheit/medizin/gesundheit-erstmals-autowaschanlage-als-herd-fuer-legionaerskrankheit-gefunden-id15655657.html).
How could this happen:
In car wash facilities, a large portion of the washing water is treated and reused for both economic and ecological reasons. As a result, Legionella can accumulate, even if the water temperature is not within their optimal growth range. During pre-washing outdoors – typically carried out using high-pressure cleaners – as well as during the washing process itself and the drying of vehicles, water is aerosolized. This allows it to enter the respiratory systems of both employees and customers.
As a preventive measure for occupational and consumer protection, Legionella testing is therefore recommended despite the current lack of specific legal requirements.
If you are interested in further information or consultation on this topic, please feel free to contact our employee Ms. Sylvia Eckhardt (Tel.: +49 2762 / 9740-83 or sylvia.eckhardt@horn-co.de).
