This is the safety limit for public radiofrequency (RF) radiation exposure in most western countries.
The limit was published back in 1998, under the assumption that RF radiation can not cause other health effects than tissue heating.
Here you can read what scientific research has discovered since then. The studies on this website are linked from reputable peer-reviewed publishers around the world. Links to articles are included.
Radiation effects on: Diabetes, Eyes, Headache, Electrohypersensitivity