UK: The Health & Safety Exectutive (HSE) has told businesses with evaporative cooling towers to do more to protect workers and members of the public from exposure to legionella.
A safety notice issued by the HSE comes after a review of outbreaks in the UK over the past ten years said to show 'common failings in control, and a potential risk of further legionella outbreaks, such as that in Edinburgh in June 2012.'

The safety notice, issued on Friday, comes during a new outbreak in Stoke-on-Trent which has so far killed one person and infected a further 15. The source of this new outbreak is not yet known, neither has it been confirmed that cooling towers are to blame, but samples are reported to have been taken from seven cooling towers in the city. Each has been disinfected.

The HSE's review of outbreaks has confirmed that cooling towers and evaporative condensers are the most common source of significant outbreaks. A failure to recognise potential legionella problems or to adopt effective control measures is said to be the reason for 90% of outbreaks.

The safety notice warns that warmer weather can allow bacteria to multiply more quickly, and that measures to prevent legionella spreading need to be reviewed regularly and whenever operating processes are changed.

The notice also stresses the need for effective and consistent monitoring of water quality and the importance of responsibilities being assigned to named individuals with proper management oversight.

More specifically, the HSE pinpoints departures from planned maintenance and cleaning schedules (allowing plant conditions to get worse, and longer periods for problems to develop); changes in the process (leading to changes in the risks, or rendering existing precautions ineffective); staff/contractor changes (leading to a loss of knowledge); intermittent use of plant (resulting in inconsistent control measures); unusual weather conditions (eg bacteria multiplying very fast in warm weather).

HSE's legionella expert Paul McDermott said: 'Our research has confirmed the importance of businesses following the well-established and readily available guidance. Through this safety notice we are reiterating what those responsible for the maintenance of water systems should be doing already.

'They have a responsibility to manage the risks they create to protect workers and the wider public. This is a reminder to them of what the law expects. Failure to comply with the law means they may face legal sanctions, including in the most serious cases prosecution through the courts.'

The Edinburgh outbreak in July killed three and infected 101 people.

An effective approach is set out in HSE's Approved Code of Practice L8: Legionnaires' Disease - The control of legionella bacteria in water systems