Health and Safety

Legionnaires’ disease – duties and responsibilities

Legionnaires' disease
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What is Legionnaires’ disease?

Legionnaires’ disease is a form of pneumonia. It is the most serious of the diseases that are grouped together under the term legionellosis – all caused by contact with legionella bacteria. Legionnaires’ disease is particularly serious because it can affect anyone, and it can be fatal. The bacteria that cause the disease are commonly found in low numbers in natural water features such as lakes and rivers, and also in reservoirs. It is uncommon for anyone to be contract Legionnaires’ disease from natural water, because the concentration of the bacteria is so low.

Why does it matter to me?

The bacteria can also be found in man-made water-filled structures such as hot or cold water systems, cooling units for air conditioning systems, and spa pools. For a property owner or landlord, the problem is that if the water conditions are right, the bacteria can flourish. The right conditions include temperatures of between 20 °C and 45 °C, which is typical of temperatures found in such structures. The presence of rust, scale and organic matter, combined with stored or recirculated water, makes the environment even more favourable for bacterial growth.

The way people contract Legionnaires’ disease is by inhaling droplets of water containing the bacteria. Cases have been traced to untreated air conditioning systems in hotels and factories. Also implicated in the spread of legionella bacteria are indoor ornamental fountains and factory emergency shower units. Droplets of water in the air are common under these conditions.

What steps can I take?

If you are an employer or a landlord, you have a responsibility for the health and safety of people on your premises. This responsibility is defined in the Health and Safety at Work Act of 1974 (HSWA). You have a duty to ensure the correct precautions are taken to reduce the risk of legionella exposure by your employees or tenants. In order to achieve this, there are a number of steps you should take.

Firstly, you need to identify sources of risk, usually by carrying out a risk assessment. Secondly, you need to manage, prevent or control any risks you have identified.

In order to achieve the above, it is essential that you keep detailed records of any assessments, risks, and the remedial actions you have taken, or plan to take.

How can I get help?

You need to work with experts who can provide you with the services you need. Services such as thorough training and awareness in legionella control processes, or carrying out detailed risk assessments on your behalf. These services can be particularly useful if you are a small organisation or a one-man band, and you don’t have the expertise or resources to put in place suitable controls.

The consequences of a Legionnaires’ disease outbreak in your premises can be devastating. Quite apart from the danger of severe illness or loss of life for the victim(s), there is also a danger of being prosecuted or sued, with the subsequent costs and loss of reputation. It therefore makes sense to seek expert help and guidance, and not to leave anything to chance in the important area of health and safety.

For more information on legionella control training or risk assessments, email us at or complete the form below.



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