Most people buying or selling property will have absolutely no idea about the risks from Legionella bacteria lurking in the building’s water system. It would be unusual for their surveyor to highlight any risks either. Obviously health risks are a concern for anyone buying or renting property, but surveyors are usually most interested in the value of the property and any factors that might make it difficult to sell in the future.

Perhaps news that this hotel failed to meet its reserve price at auction after it was forced to close following repeated discovery of Legionella in its water system, will change that attitude. Two years ago the hotel was valued at $10 million, but failed to reach the required minimum price of $2 million.

Press reports this week suggest that tennants in Norwich were made to leave their homes with just 12 hours notice due to a Legionella problem. Whilst we are familiar with schools, hospital wards, swimming pools, cooling towers and even police cells being closed down due to Legionella contamination I think this is the first report of people being asked to leave their own homes.

The response seems to have been fast and that is commendable. The nature of the response is however not so clear. Firstly residents were advised not to drink the water despite the fact that most experts do not consider drinking water contaminated with Legionella to be a risk (there may be a theoretical risk if the water were aspirated). Secondly, and more alarmingly, no advice appears to have been provided on the use of showers which are recognised as being a potential method of infection. Finally it is not clear why occupants were expected to vacate flats to enable flushing and decontamination of the water system. The lesson to learn here is that Legionella contamination is not uncommon so duty holders should not only have a risk assessment in place but have a clear management plan in place which documents what is necessary to deal with a problem. The time to be learning about, and understanding the risks from Legionella infection is not when you are making critical decisions.

Whilst it is common to think of Legionella risk in terms of cooling towers, showers and spas more unusual sources of infection also exist. The UK Approved Code of Practice (’the L8′) requires those responsible for health and safety to assess the risk of infection anywhere water is used or stored. Often process water is overlooked when assessing these risk. The HSE has recently highlighted the risks from “aqueous tunnel washers”. This particular report follows up on two cases of Legionnaires’ disease in the UK which were associated with a particular employer. Tunnel washers consist of a series of spray heads through which pass components to be cleaned before for example they are painted.

Whenever there is a mechanism for generating an aerosol of water there must be some risk from Legionella bacteria. That risk can be minimised when the water temperatures do not allow the bacteria to grow or by keeping the system clean so that nutrients are not available. In this particular case, and in other industrial processes, car washes etc there is no such bacterial control in place - the water is not kept clean, and may even be recycled for economic and environmental reasons, and is often heated or held in tanks at room temperature which allow bacteria to multiply.

The HSE have now provided detailed guidance on the design and maintainance of tunnel washers, and much of the information provided could be extrapolated to other industrial processes. If you use water for industrial processes, cleaning etc. then you need to assess the risk to staff and the public who may be exposed to any aerosols. Detailed risk assessments and action plans can take time to develop, during which time your staff and the public may continue to be exposed to hazardous bacteria. We would suggest that total microbial AND Legionella monitoring is essential to understand the current level of risk in your system whilst you are waiting to conduct a detailed risk assessment and implement its findings. Once that risk assessment is in place regular monitoring will be necessary to demonstrate that the control measures are effective and being properly maintained.

Legionella bacteria are known to be a problem in dental equipment, and obviously with aeosols being generated within the mouth these present a significant risk to patients. Nicosia General Hospital in Cyprus has just closed their dental departement after finding Legionella bacteria in some of the equipment. Some of the statements from the hospital are surprising: the normal rational for testing is to demonstrate that your cleaning, disinfecting and control measures are adequate and effective. To rely on testing as a trigger for disinfection seems to be closing the door after the horse has bolted. Dozens of people have potentially been exposed to the bacteria between the sampling/testing intervals. Using traditional laboratory analysis takes time - during which people continue to be exposed to potential sources of infection.