Do not stand directly against an oven for long periods of time while it is operating. Materials containing water, for example foods, fluids or tissues, readily absorb microwave energy, which is then converted into heat. This Information Sheet discusses the operation and safety aspects of microwave ovens used in the home. More details about the nature of electromagnetic fields and health effects of radiofrequency and microwave fields are available in WHO Fact Sheets 182 and 183.