Legionnaires' outbreak: Cooling towers identified as probable source

Cooling towers on one Edinburgh street in the shadow of Hearts stadium have been identified as the probable source of the fatal Legionnaires' Disease outbreak.

Test results presented to the expert team investigating the outbreak which has killed two men have suggested that the source of exposure is most likely to be the cluster of cooling towers on Wheatfield Road.

Although not named in the report, two businesses based in the street, North British Distilleries and pharmaceutical giant Macfarlan Smith are at the centre of investigations.

Both companies were served with improvement notices as part of the investigation following the outbreak, along with the National Museum of Scotland.

So far 47 cases of the disease have been confirmed in the capital, along with a further 46 suspected cases, with two people currently in intensive care and 16 on other wards in hospital.

The outbreak has killed two people, including 56-year-old Robert Air.

Dr Duncan McCormick, consultant in Public Health Medicine and chair of the Incident Management Team, said: “Evidence to date is pointing to an airborne exposure to Legionella in the south west of Edinburgh starting around Wednesday 23 May. The IMT took immediate action on Sunday, June 3, when a cluster of cases was identified, to ensure cooling towers in the area were treated with high doses of chemical disinfectant.

“Our investigation into the outbreak is on-going and it is reassuring that the number of people who have been confirmed as having Legionnaires’ disease has slowed over the past week in line with our expectations.”

IMT have analysed samples from patients along with epidemiological and meteorological evidence, including the location of possible sources and weather patterns, to conclude that that there was a common outdoor, airborne exposure to the Legionella bacterium over south west Edinburgh, starting around Wednesday, May 23.

However, there is currently no microbiological evidence to confirm the presence of Legionella pneumophila in samples form potential sources. Investigations are ongoing.

Lothian and Borders Police and the Health and Safety Executive are jointly investigating the two deaths under the direction of the Crown Office and Procurator Fiscal Service (COPFS) Health and Safety Division.

A spokesman for the City of Edinburgh Council said: “Our role in the investigation is to take samples from cooling towers in the city which are then analysed by our Edinburgh Scientific Services laboratory.

“We have also carried out inspections at cooling towers and environmental health staff have visited various other locations as part of our investigation into this public health incident.”

In a statement, Macfarlan Smith representatives said: "We note in particular that after extensive testing, there is no microbiological evidence to positively confirm the presence of Legionella bacteria in any of the samples taken from any of the potential sources.

We took samples immediately after the Environmental Health Department took their samples on June 3 and these have been independently tested. These tests show no presence of Legionella bacteria. We have supplied these test results to the HSE and to the Environmental Health Department of The City of Edinburgh Council in light of the ongoing investigation.

"In addition, as part of our regular maintenance programme, our cooling units were cleaned in early May and routine Legionella testing took place on May 14. Those independent test results also showed no presence of Legionella bacteria and these results have also been shared with the HSE and Environmental Health Department. Routine samples are taken weekly from each of our cooling units and are independently tested for bacterial growth. These samples have shown no abnormal levels of bacterial growth before or during the outbreak. Since the first visits from the Environmental Health Department and the HSE in relation to this outbreak, we have cooperated fully with the investigation and will continue to do so.

"Macfarlan Smith has always treated the health and safety of our employees and the general public as our highest priority. Our employees are drawn from the local community and, as members of that community, we would like to stress that our thoughts are with those affected by the outbreak."

A spokesman for North British Distillery added: “Our sympathies remain with all those affected by the Legionella outbreak.

“Throughout this difficult period we have remained confident in our health and safety procedures relating to the cleaning and testing of our cooling towers.

“Our cleaning and testing regime has always been rigorous and has complied with the statutory L8 guidance set by the HSE. All of our cooling towers are continuously monitored and dosed and all three cooling towers are regularly cleaned.

“The three most recent Legionella analyses taken at North British Distillery on either side of the outbreak - 19 April, 3 June and 5 June - were submitted for external independent assessment, and confirmed ‘all clear’ results for all three cooling towers.

“Furthermore we would like to make it clear that the actions required by the HSE’s improvement notice – which related to a cooling tower that was not in operation on May 23, the date highlighted by NHS Lothian as the suggested start of the outbreak - have been fully complied with.

“We can confirm that we have started the distillery back up in a controlled manner. This decision was taken in full consultation with the HSE.

“We will continue to work with HSE and all other relevant authorities to ensure that our operations continue to meet the standards for safe operation of our plant.”

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