6 September 2005
CDHB Releases Water Cooling Tower Results
Today the Canterbury District Health Board has released the name of the business in Christchurch whose water cooling tower exceeded the recommended guidelines for legionella in April this year at the start of the outbreak of Legionnaires Disease.
The company has worked with health authorities, the Dept of Labour through OSH, and the Christchurch City Council to shock treat and test its tower on a regular basis with results that are now well below the recommended danger level.
‘The outbreak of Legionnaires Disease in Christchurch earlier this year prompted a large-scale checking system to be put in place to not only identify all the cooling towers in the city, but to simultaneously survey the people and their families who had been diagnosed with Legionnaires Disease to try and draw some scientific conclusions as to location, strain and cause,’ said the CDHB’s Interim Chief Executive Dr Karleen Edwards.
‘It was a very protracted process complicated by the fact that there was no single database of water cooling towers.’
‘The laboratory results of tests taken from patients was consistent with a strain of Legionella linked specifically to water cooling towers which was why we focused on the towers as the probable cause.’
Dr Edwards said of the early results that came through, one cooling tower belonging to Ravensdown Ltd had a high level of colony forming units (cfu) of the same strain of Legionella identified later in all 19 cases.
Of 139 water cooling towers in the city, with more than 80% of the test results now back, only four had tested positive, of which three were of a different strain of Legionella and at a level of cfu that was not high or moderate.
‘Ravensdown has acted very responsibly and we commend them for their swift action at the outset in volunteering their results and working with us to shock treat and test their tower. They advised their staff and have conducted their own research into what has happened.’
‘The DHB’s concern has always been for public safety and to ensure that correct and accurate information has been given to the patients and families who have suffered from Legionnaires Disease during what has been a very difficult time.’
The test results back now show that the public risk following the outbreak has been effectively dealt with, which is good news for the public.
Dr Edwards said she endorsed earlier comments from the Medical Officer of Health Dr Alistair Humphrey that there are lessons to be learned from the outbreak. She hoped that the industry sector would now take the initiative and look at improving protocols and regulations to assist businesses to develop a more structured system for managing the potential risk from cooling towers.