Calls grow for cooling tower register after Legionella outbreaks

ORF reports that tighter controls on cooling towers are being urged after Legionella outbreaks killed three people in Linz this year and sent 42 people to hospital in Vorarlberg last year. Ten of those patients required intensive care.

Legionella bacteria thrive in warm water, particularly at temperatures between 25 and 45 degrees Celsius. If water contains high levels of the bacteria, they can enter the lungs in tiny droplets and cause severe pneumonia.

Cooling towers remove heat from technical equipment. Warm water is circulated through the tower while air flows through it, causing some of the water to evaporate and cooling the rest. The temperatures in the circulation water can support Legionella growth, especially if the water stands for longer periods. Dirt and inadequate disinfection can also contribute.

The bacteria cannot be seen or smelled, so they must be detected through laboratory testing. Chemist and laboratory operator Edwin Kalb said testing frequency depends on the type of system. About 1,000 of every 10,000 samples show elevated levels, he said, although an acute danger is rare.

Legionella testing is mandatory for large drinking water systems, including larger residential buildings, hotels, industrial facilities and care homes. However, authorities do not check whether the required testing has actually taken place.

The issue is also at the centre of the ongoing Rattpack trial. The next hearing is scheduled for autumn. Investigators believe a cooling tower at the Wolfurt-based packaging company was the source of a Legionella outbreak. The defendants linked to Rattpack blame the maintenance company, while an employee of that company says Rattpack did not commission Legionella tests.

The number of cooling towers in Vorarlberg is not officially recorded. The TÜV is now calling for a register, which Kalb supports. He said better information about the systems operating in the region would allow authorities to monitor their maintenance more effectively.

People can also reduce the risk in their homes by regularly flushing taps and other fittings that are not used often, said installer Stephan Descher, deputy head of the installers guild. Modern boilers usually heat themselves once a week to kill the bacteria, but older systems may not do this automatically.

Descher also recommends running all taps for several minutes after arriving at a hotel, while leaving the room to avoid breathing in any spray. Saving water remains important, he said, but so is awareness of the risks posed by Legionella.