Asphalt paving machine causes Legionellosis

A paper written by Mireia Coscolla et al entitled “Legionellosis outbreak associated with Asphalt paving machine, Spain 2009” (DOI: 10.3201/eid1609.100248) described an outbreak of Legionellosis in Alcoi, Spain in 2009 that proved difficult to track down.

From 1999 to 2005 the incidence of Legionellosis in Alcoi had been continually high, this led in July 2009 to an epidemic being declared when an increase in cases was seen.

Patients houses and municipal waters were checked with no sign of the cause of the illnesses so the authorities started to look at other environmental sources and eventually noted that an asphalt laying machine which had been fed by spring water as opposed to municipal water had the same sequence type of legionella bacteria present.

Subsequent investigation showed that the water tank and aerosolisers within the machine (see the photograph above) were the source of the bacteria so an immediate cleaning regime and use of chlorine as a biocide was introduced which overcame the problem.

This epidemic had led to 11 people with Legionellosis and only when the machine was removed from service and cleaned did infections in the area stop.

This case shows that Legionella bacteria are very opportunistic and one shouldn’t stop considering all sources of water that you are responsible for and ensuring a risk assessment of these sources is carried out and suitable remedial action taken if appropriate.

Collaton Consultancy Limited are Legionella experts and consultants so if you need help with Legionella Risk Management do not hesitate to contact us via


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