Mycobacterium chimaera infection in patients who have had cardiac bypass surgery has recently been associated with contamination of water in heater cooler units. Those responsible for infection prevention and control programs face the challenge of responding to this rare but potentially life-threatening and avoidable healthcare-associated infection. Infection control professionals need to be aware of this issue and take an active role in formulating hospital responses. Policies should be rational and appropriate to the level of risk, should minimise service disruption and costs, and recognise that evidence about risk mitigation measures is still emerging. This paper provides background information to the topic and proposes a risk management based approach to heater cooler units in hospitals that perform cardiac bypass surgery, so that infection control professionals can develop a local, tailored response.