Legionella bacteria are common in warm, stagnant water found in plumbing units, hot water tanks, water stored in the cooling towers, at times in the condensers of air-conditioner, soil in the pots and even in the spa pools. Although, home and vehicle air conditioners cannot be considered as a source. The bacteria are not able to survive in hot water sources where water temperature 60 degrees Celsius or above.

The Nelson Marlborough Public Health Service had marked the Blenheim cooling towers as a possible source of legionella disease which infected 3 people admitted to Wairau Hospital on May 9. Water samples had been derived from the cooling towers where the 3 contaminated people had visited during the past 2 months while the cooling units were directed for the chemical treatment in order to curb the further spread and to eliminate the risk of infection.

The Nelson Marlborough Medical Officer of Health, Jill Sherwood, said that the people diagnosed positive for a pneumophila serogroup, 1 form of the disease, which contributes roughly half of legionella cases were acknowledged in New Zealand while compared the situation with a case occurred during the past year.

However, the disease is not communicable but most susceptible to affect people aged 50 or above including smokers, and individuals with suppressed immune systems.