RESUMO
Many cases of medically unexplained physical symptoms (MUPS) have been recorded. The sufferers of a large proportion of the more recent cases believe their illness to have been caused by exposure to chemicals in the environment. The evacuation of Melbourne airport in February 2005 exemplifies a recent health "scare" where people thought they were ill but no tangible evidence of illness was recorded and no chemical or biological agents detected. It was suggested that the "illnesses" in this instance were psychogenic. In such cases, where psychogenic illnesses are a potential diagnosis, risk managers need to think carefully about how the message is communicated, as contested causation often arises. While environmental investigations and health testing are important steps in the diagnostic process, they are used more to exclude possibilities, that is, to prove a negative, rather than to discover the "smoking gun." An example of a case of MUPS that lasted several years in a primary school is provided to illustrate that different forms of investigation are needed and that there is a need to consider a potential diagnosis of MUPS relatively early in the investigation. It is important to recognise the potential for MUPS so that the psychogenic elements of the illness can be investigated and treated.