Legionnaires’ Disease – What it is and how could it affect you?

What is Legionnaires’ disease?

Legionnaires’ disease is a lung infection. It’s named after a severe outbreak which affected an American Legion meeting in 1976. 

The disease is uncommon, but can be particularly serious. The disease:

• Occurs more frequently in men than women
• Usually affects middle-aged or elderly people
• More commonly affects smokers or people with other chest problems

Where does the disease come from?

Legionnaires’ disease is caused by a bacterium called Legionella pneumophila. It mainly lives in water, for example ponds, where it does not usually cause problems.

However, outbreaks occur from purpose-built water systems where temperatures are warm enough to encourage growth of the bacteria. This includes cooling towers, evaporative condensers, whirlpool spas and from water used for domestic purposes in buildings such as offices, factories, hospitals, care homes and hotels.

Most community outbreaks in the United Kingdom have been linked to installations such as wet cooling towers or evaporative condensers, which can spread droplets of water over a wide area. These are found as part of air-conditioning and industrial cooling systems.

How does a person get Legionnaires’ disease?

You could catch the disease by inhaling small droplets of water suspended in the air which contain the Legionella bacterium.

Don’t worry, most people who are exposed to legionella don’t become ill. However, it is worth being aware of the risks and mitigating them. 

How do you control it?

To prevent the occurrence of Legionnaires’ disease, companies that operate these water systems must comply with regulations requiring them to manage, maintain and treat them properly.

The water used in the systems must be treated correctly and the system cleaned regularly.

However, the starting point for any control programme is a detailed risk assessment of the building’s water systems. 

My premises is closed or empty – is it still at risk?

If your business has temporarily (or even permanently) fully shut down, there is additional guidance available. 

• Take the heat source off any Domestic Hot Water System
• Evaporative cooling systems must be maintained as usual or switched off completely 
• Minimise stored water – water within cold water storage tanks should be turning over every 24 hours
• Don’t drain down pipework
• Make sure all sentinel taps and shower heads are flushed at least every week 
• Don’t be slack on your regular risk management. Continue temperature monitoring procedures, cleaning routines etc 
• Put up signage throughout your building advising that the system is not in use 
• Before starting up again, all hot and cold water systems should be flushed through the fresh mains water 
• Put in place a recommissioning plan, getting suppliers and quotes lined up to clean, disinfect, chlorinate and sample water to ensure it is free from the bacteria 

The responsibility for legionella control lies with you, so it’s incredibly important you recommission all water systems safely and thoroughly test samples to ensure water is free from nasty and harmful bacteria. 

How long does the disease take to develop?

Symptoms of Legionnaires’ disease will typically start to develop within 2 to 10 days after you’ve been infected by the bacteria. In some people it may take longer, so it’s best to look out for symptoms for around two weeks after being exposed. If you are in any doubt you should see your doctor immediately.

How to diagnose Legionnaires’ disease

Because the symptoms of Legionnaires’ disease are similar to the flu, it’s not always easy to diagnose. If you are worried, you should see your doctor who will take a blood or urine test. 

If you suspect that you may have got the illness as a consequence of your work then you are advised to report this to your manager, as well as your health and safety representative and occupational health department, if you have one. This is because there’s a legal requirement for UK employers to report cases of Legionnaires’ disease that may be acquired at their premises to the Health and Safety Executive (HSE). 

Legionnaires’ disease risk assessment

A Legionnaires’ disease risk assessment is an important health and safety process that will protect you, your business and others from harm. In the UK it’s a legal requirement for all businesses to have one. You can find more information here. 

If you have any specific questions, or would like to speak to our risk management team, please get in touch.