Are environmental magnetic fields dangerous?

In the general environment, at home and in the factory or office, people are exposed to electromagnetic radiation from computers, domestic appliances, power transmission lines and manufacturing tools and products. It is often thought that the electromagnetic fields associated with these may have adverse effects, and indeed court cases have sometimes upheld this. The evidence, however, remains ambiguous and a causal relationship between the fields and illness is not accepted generally. Despite this, in most developed countries, safety codes or laws have been adopted to protect the individual. These define permitted levels of exposure to both static and time-varying fields, the effects of both of which are considered in this article.