Legionnaires' Disease is a potentially fatal form of pneumonia which can affect anybody, but which principally affects those who are susceptible because of age, illness, immunosuppression, smoking etc.
It is caused by the bacterium Legionella pneumophila and related bacteria that can be found naturally in environmental water sources such as rivers, lakes and reservoirs, usually in low numbers. As they are commonly found in environmental sources they may also be found in purpose built water systems such as cooling towers, evaporative condensers and whirlpool spas.
If conditions are favourable the bacterium may grow creating conditions in which the risk from Legionnaires' disease is increased. It is therefore important to control the risks by introducing measures outlined in the Approved Code of Practice & guidance document Legionnaires' disease - The Control of legionella bacteria in water systems (L8).
1. Legionnaires' disease is a type of pneumonia. It was named after an outbreak of severe pneumonia that affected a meeting of the American Legion in 1976. It is an uncommon but serious disease.
2. It is actually one of a group of similar diseases collectively known as legionellosis. The other forms, eg Pontiac Fever and Lochgoilhead Fever, have similar symptoms but are not as serious as Legionnaires' disease.
3. Legionnaires' disease occurs more frequently in men than women. It usually affects middle-aged or elderly people, and it more commonly affects smokers or people with other chest problems.
4. About half the cases of Legionnaires' disease are caught abroad, and useful advice on travel can be obtained from the European Working Group for Legionella Infections (EWGLI). The other half are the result of infections acquired in the UK.
5. The agent that causes Legionnaires' disease is a bacterium called Legionella pneumophila. People catch Legionnaires' disease by inhaling small droplets of water suspended in the air, which contain the bacteria.
6. Certain conditions increase the risk from legionella:
However, remember that most people exposed to legionella do not become ill, and Legionnaires' disease does not spread from person to person.
7. The symptoms of Legionnaires' disease are similar to those of flu:
In a bad case there may also be pneumonia, and occasionally diarrhoea and signs of mental confusion.
8. Legionella bacteria are widespread in nature, mainly living in natural water systems, eg rivers and ponds. However, the conditions are rarely right for people to catch the disease from these sources.
9. Outbreaks of the illness occur from exposure to legionella growing in purpose-built systems where the water is maintained at a temperature high enough to encourage growth, eg cooling towers, evaporative condensers, spa pools, and hot water systems used in all sorts of premises (work and domestic).
10. Most community outbreaks in the UK have been linked to installations such as cooling towers, which can spread droplets of water over a wide area. These are found as part of air-conditioning and industrial cooling systems.
11. Fatal cases of Legionnaires' disease have also been associated with spa pool demonstrations.
12. To prevent exposure to the legionella bacteria, you as a dutyholder must comply with legislation that requires you to manage, maintain and treat water systems in your premises properly. This will include, but not be limited to, appropriate water treatment and cleaning regimes.
13. Remember, legionella can grow in any workplace if the conditions are right - you do not have to work with microbiological agents, eg in a laboratory, for exposure to occur. If you are responsible for any of the water systems described in HSE's Approved Code of Practice (ACoP) and Guidance "Legionnaires' disease: The control of legionella bacteria in water systems" (L8) you will need to assess the risk of employees and others in the workplace contracting Legionnaires' disease.
14. Copies of L8 can be purchased from HSE Books. HSE also publishes several free leaflets and a video explaining legal duties and the control of legionella in cooling systems and hot/cold water systems available from HSE Books.
15. Separate regulations (The Notification of Cooling Towers and Evaporative Condensers Regulations 1992) require the notification of cooling towers to your Local Authority (contact them directly for further information).
16. If you suspect that you or an employee have contracted the disease as a result of your work then there is a legal requirement to report cases to the Health and Safety Executive.
17. L8 gives advice on actions to take in the event of finding legionella in your workplace and also during an outbreak.
18. The HSE has established a Legionella working group with the aim of improving communications between stakeholders and to develop a consistent approach to Legionella-related plant and management systems.
19. Further information on the activities of the group can be found
here:
HSE Legionella
Committee
20. If you are responsible for premises inspected by your Local Authority you should direct any queries about legionella in your workplace to them.
21. The Hazardous Installations Directoriate (HID) has a proactive inspection programme looking at legionella in cooling towers, further information on this can be found in their Operating Plan.
