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November 6, 2015

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Legionella – the invisible killer

By Debbie Green

Proactive health and safety management continues to play a significant part of everyday working life. For duty holders this means identifying hazards and preventing or reducing the risks wherever possible. But there are many risks to health that are not so immediately obvious.

One example of such a risk is that presented by Legionella – the bacteria responsible for Legionnaires’ disease. Legionella pneumophila (accounting for 96% of Legionnaires’ disease cases) frequently occurs in natural water sources such as rivers, lakes and reservoirs, but usually in low numbers.

Legionella, if it encounters favourable conditions, may colonise areas within building water systems for example cold water storage tanks, cooling systems, hot water cylinders and redundant pipework. The bacteria is transmitted through the release of aerosols such as those produced by showers, spray taps and misting devices. The disease is contracted through inhaling the fine water droplets containing legionella bacteria, which results in symptoms similar to those of pneumonia.

Legionnaires’ disease was first identified in 1976 when an outbreak occurred at a hotel during the State Convention of the American Legion. Today it is responsible for an average 300 reported cases each year in England and Wales, and proves fatal on average, in around 10-12% of cases. If acquired in the community; mortality in a healthcare setting or hospital rises to around 45%.

Certain members of the population are more vulnerable to legionella infections and these include the elderly (risk increases with age from 50+) and those with ongoing issues affecting their health. Increases in the number and proportion of older people in the UK population mean that the pool of ‘susceptible individuals’ is set to expand. Percentage of persons aged 65 and over increased from 15 per cent in 1985 to 17 per cent in 2010, an increase of 1.7 million people. By 2035 it is projected that those aged 65 and over will account for 23 per cent of the total population1. This will no doubt result in a rise in cases, and employers of older people and those involved in elderly care need to be particularly aware.

Males are two and a half times more likely to contract Legionnaires’ disease than females and in around 73% of all cases, there are predisposing factors that affect susceptibility.

Statistics compiled by the French National Public Health Centre in 2001 showed the significance of smoking in relation to increased risk. Of 807 reported cases, 558 of these were identified as having the following predisposing factors:

  • Diabetes (10%)
  • Cancer or blood disease (11%)
  • Immunosuppressant treatment (12%)
  • Smoking (40%)

In the UK in 2001 there were 1.3 million people with diabetes; this has risen by 66% to 3.9 million people in 2015 and it is estimated to reach 5 million by 20252, with many cases remaining undiagnosed. If this study were to be repeated today it is likely that the prevalence of diabetes would result in an increased number of related cases of Legionnaires’ disease, and this again increases the percentage of the population that may be susceptible to legionella infections.

Many public and private sector organisations remain unaware that under the Management of Health & Safety at Work regulations and the COSHH regulations, they have a legal obligation to identify and manage the risks associated with Legionella. Contrary to popular opinion, the control of Legionella does not just apply to premises with cooling towers or air conditioning. In fact organisations should ensure that all buildings have a suitable risk assessment of the water systems carried out, and that precautions are taken to reduce the risk of Legionnaires’ disease.

Legionella proliferation can be controlled through a combination of regular monitoring and maintenance of water supplies, water temperature control or through the application of water treatment. The Health & Safety Executive’s Approved Code of Practice – ACOP L8 (fourth edition 2013) ‘Legionnaires’ disease: The control of legionella bacteria in water systems’ details the responsibilities of building owners and managers. The associated guidance note HSG274 (parts 1-3) provides practical advice on how to prevent or control the risks.

Failure to take adequate precautions against exposure to legionella could mean establishments are leaving themselves liable to prosecution and financial loss.

It is also costly to the UK economy with the NHS bearing the brunt. In the 2012 Edinburgh Outbreak (101 cases, 3 deaths), the cost of providing hospital care was almost ÂŁ900,000 with over 950 patient care days logged across intensive care, high dependency and general wards.

Nemco Utilities are registered independent specialists in Legionella Management and are able to offer expert advice and practical solutions to control the risks, and ensure organisations comply fully with their legal obligations. Debbie Green, Operations Director, believes companies should tackle the problem head on. “Businesses simply cannot afford to ignore the risks. Implementing a legionella management programme is simple and easy to administer – there really is no excuse for non compliance.”

Recent high profile corporate manslaughter cases have heightened public awareness regarding the obligations of companies to ensure the safety of their workers, customers and all those affected by their business. With the average number of annual reported cases on the rise, and significant increases in susceptible people in the population, duty holders must ensure a current and effective legionella management system is implemented.

Most outbreaks and individual cases of Legionnaires’ disease can be traced back to a lack of training and awareness, inadequate management and control or poor communication.

debbie GreenDebbie Green is operations director of Nemco Utilities Ltd and regularly speaks on legionella mangement and water hygiene in the workplace. For further information or advice on Legionella, contact Nemco Utilities free on 0800 0741237.


1 Source: 2012 Polulation Data – Office for National Statistics, National Records of Scotland, Northern Ireland Statistics and Research Agency

2 This figure was worked out using the diagnosed figure from the 2013/14 Quality and Outcomes Framework and the AHPO diabetes prevalence model

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Robert Hogan
Robert Hogan
8 years ago

It is unfortunate that all facilities do not use available and inexpensive systems to protect against this type of infection. As illustrated in the attached link, it’s time to act to protect employees and visitors in public buildings. The new legislation in New York is a good start.