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Legionella- what is it, and what are my responsibilities?

Legionella can present a very serious risk to those who may inadvertently come into contact with significant amounts of the bacteria. In understanding the need for a legionella assessment, you can begin to put into place steps that will keep your employees safe. In this blog we tell you what it is, what you need to know and why an assessment is needed…

16 April 2019

Legionella can present a very serious risk to those who may inadvertently come into contact with significant amounts of the bacteria. In understanding the need for a legionella assessment, you can begin to put into place steps that will keep your employees safe.

What is legionella?

Legionella is a bacterium that appears naturally in rivers, lakes and reservoirs, but they are relatively low in number. When legionella appears in man-made water systems, such as hot and cold-water systems and evaporative condensers, they can multiply exponentially since such systems create an environment which they favour. The temperature that is most conducive for legionella to multiply in water is between 20 and 45 °C, and this produces a threat to human health when water droplets are dispersed into the air. Inhalation of the legionella bacteria can lead to legionnaires disease – a pneumonia like disease with a 10% risk of death if contracted. Thankfully, legionnaires disease isn’t particularly common in the UK, but it is still a significant concern, with 814 cases identified in 2018.

What does the law say?

Under the Health and Safety at Work Act 1974, you have a responsibility to address the causes or potential causes of legionella in your environment. It should be part of your risk assessment procedure to check for legionella, but to do so you should ensure that you or a responsible person are competent to complete the task. It is recommended that the competent person has undergone specific training relating to legionella and legionnaires disease to complete the task.

What is determined in a legionella assessment?

The legionella assessment should look at foreseeable risk, i.e. places where it is likely that legionella may multiply. These can include the following:

• Cooling systems
• Hot and cold-water systems
• Spa pools

The assessment must be conducted by someone with due knowledge of the system, as well as of legionella. They can begin to identify likely areas where legionella may be present in a system, such as areas where bacteria growth is promoted, such as those at 20-45°C, or where rust, sludge or organic matter may gather.

The resulting risk assessment will include an identification of potential legionella risks, means of removing the risks, monitoring procedures, records of the checks conducted, and arrangements for future assessments.

Each system requires a risk assessment, although it is not essential to introduce control measures into each. This is the case if the system is found to be low risk and managed correctly. However, in this situation it is still important to conduct regular risk assessments to make sure that the risk of legionella doesn’t increase, should something change in the system. When looking at a possible source of legionella, you need to consider the whole system as a risk, rather than merely the part of the system in which the potential for legionella to multiply is most high. The assessment should be thorough and include even parts of the water system that are only used intermittently.

In line with your responsibilities as an employer, you are required to consult with employees and their representatives on the potential risks of exposure to legionella.

How to reduce the risks of legionella

If your assessment determines that there is a reasonable risk of legionella in the system, then you are responsible for reducing the risk as much as is reasonably practicable. If this is the case, you need to appoint someone who is competent to make changes to the system. When controlling any risks from legionella, the you need to appoint someone who is a responsible person, who has ‘sufficient authority, competence and knowledge of the installation’ to make sure that the procedures are conducted effectively. By ensuring that such a person is in place, you can deliver the communication that is required to adequately and effectively manage any potential legionella in the system.

There are steps you can take to minimise the threat from legionella. Firstly, avoid keeping water between 20 and 45°C. These are the optimal temperatures for legionella to begin to multiply to dangerous levels within a system. Materials which may provide nutrients to bacteria in a system should be avoided since they also contribute to the possible growth of legionella within a system. You can take steps to reduce the potential for legionella to grow, and there are also treatment options available that can reduce the risk of legionella growing in a system. Since legionella becomes most dangerous to humans when it is airborne, you should control the release of water spray into the air.

Legionella represents a very real threat to the safety of employees, and visitors to your business. By taking its management seriously and creating plans for not only dealing with any potential outbreaks, but also performing regular risk assessments you can ensure that you are reactive and responsive to any changes that may develop.

Need some help with health and safety? Think of us an extension to your existing team – we are your dedicated health and safety manager, available at any time. Just give us a call on 01522 533388 or drop us an email.

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