Cooling Towers, Legionella Management & The Portugal Legionnaires’ Disease Outbreak
The current outbreak of Legionnaires’ disease in Portugal is now one of the largest ever recorded and is believed to have been caused by legionella contaminated cooling towers at a fertilizer factory at Vila Franca de Xira, about 30 kilometres north of Lisbon.
The importance of cooling tower legionella risk management was brought home this week with the news that cooling towers at the Portuguese fertilizer plant were said to be the likely source of the outbreak of Legionnaires’ disease that has now seen over 300 people infected and 8 people killed.
This has made it one of the world’s largest ever outbreaks of the deadly disease, with the WHO (World Health Organisation) classing the outbreak as a major public health emergency.
In view of the tragic outbreak of Legionnaires’ disease in Portugal, it is vital that organisations using cooling systems (which may consist of a cooling tower or evaporative condenser) conduct a legionella risk assessment and put into place measures that are appropriate to control the risk of legionella and a subsequent outbreak of Legionnaires disease.
Cooling tower legionella safety - general approach
As can be seen from the outbreak in Portugal, there is a considerable risk from legionella in both cooling towers and evaporative condensers, and serious problems can rapidly spiral out of control.
Fortunately, if appropriate risk management plans are put into place and implemented correctly, it is possible to significantly reduce the risk of any outbreak of Legionnaires’ disease.
It is vital that organisations using cooling towers conduct a comprehensive legionella risk assessment and put into place measures that are appropriate to control the risk of legionella.
The UK’s Health and Safety Executive (HSE) has published an effective approach in its Approved Code of Practice document: L8: Legionnaires' Disease - The control of legionella bacteria in water systems.
After an in-depth study of previous outbreaks of Legionnaires’ disease, the HSE have identified the steps that all companies who utilise cooling systems should take:
- Firstly, the sources of risk should be identified and then assessed.
- The next step is to prepare an action plan to prevent or control the risk
- This should then be implemented, managed and effectively monitored
- Detailed records should be kept of all precautions
- A senior person should be appointed to be responsible for ensuring the previous steps are carried out correctly and effectively
Identifying and controlling risk
Although the source of the legionella outbreak in Portugal has been attributed to the cooling towers, the reasons why will take somewhat longer and will require detailed investigation.
However, we can look at previous outbreaks and according to the Health and Safety Executive, 90% of such outbreaks have failure to identify and control risk as the root cause.
The HSE says that failure to identify and put into place effective controls can leave such facilities vulnerable to a range of threats, such as:
- Failure to keep to planned cleaning and maintenance schedules. This can result in plant conditions getting worse, and allowing longer periods for problems to develop.
- Changing processes, which can lead to changes in the risk and existing precautions and controls becoming ineffective.
- Loss of knowledge due to staff or contractor changes
- Inconsistent control measures due to an intermittent use of the plant
- Unusual weather conditions, for example, legionella bacteria multiplying quickly in warmer weather.
Each site should have its own scheme with the intention of controlling the specific risks to that system, and should be backed up by rigorous working procedures.
This scheme should be updated when there is any change or issue that can have an effect on the ability to effectively control risks, such as in the examples above.
As well as managing and controlling risk, it is vital that rigorous monitoring of the water quality is undertaken, including:
- chemical monitoring
- biological monitoring
- visual checks to ensure everything is working as it should be
It can be useful to routinely monitor bacteria levels, but in no way is this a substitute to ensuring the plant is kept in the best condition possible and cleaned on a regular basis.
System monitoring and then subsequently interpreting the results (including identifying any trends etc.) all need to be done by someone who has specialist knowledge.
Senior managers and the "responsible person"
Both the appointed responsible person and the general senior management team should seek assurance that effective controls, monitoring and auditing are all in place and any results are acted upon promptly.
As well as the failure to identify and control risk, according to the HSE poor communication and a lack of training are contributory factors in Legionnaires’ disease outbreaks.
It is therefore essential that everyone involved is trained, competent and fully aware of their role and responsibilities, and clear communication channels are in place between the different stakeholders involved, such as management, maintenance staff, contractors and subcontractors.
It is important that individuals are given specific roles and responsibilities, with a rigorous process in place for the tracking and signing-off of completed work as well as the oversight of contractors.
Legionnaires' risk assessment
Expert legionella risk management support
Legionella Control International ensures world class solutions are implemented to minimise, control and prevent the risk of legionella outbreaks in organisations across the UK and internationally.
Offering independent, impartial advice, they offer companies an extensive range of legionella risk management services including risk assessments, compliance audits, training, assessment of water systems, crisis management, and laboratory testing as well as an array of other essential options all designed to safeguard against legionella.
To find out more about how Legionella Control International can help with the management of cooling towers, and other cooling systems please contact us:
152 City Road
London EC1V 2NX
Tel: +44 (0) 203 637 47 48
Unit B Badex Building
Manchester M17 1AY
Tel: +44 (0) 161 877 0586