The research program calls for laboratory studies in animal, cell, and genetic research, as well as large scale epidemiologic studies. The issue of critical concern is radio-frequency radiation exposure to the head and brain from the antenna of the cellular telephone. The primary health risk under investigation is brain cancer, but other health endpoints may be explored as well. The studies will employ exposure frequencies both in the range used by current cellular telephones and in higher ranges projected for the next wave of cellular technology. Initial research relevant to the program has included such diverse tasks as developing artificial human head models to measure the amount of radio-frequency radiation absorbed from cellular telephone use and investigating the effects of radio-frequency radiation exposure on breaks in the DNA of rat brain cells. A major epidemiologic cohort study of cellular telephone users has also been launched to examine the patterns of telephone usage, such as frequency and length of cellular telephone calls, as well as brain cancer mortality within the cohort.