Summary form only given. Low-frequency magnetic fields induce circulating currents within the human body. The strength of these currents depends on the intensity of the outside magnetic field. If sufficiently large, these currents could cause stimulation of nerves and muscles or affect other biological processes. To date, no adverse health effect from low level, long-term exposure to radiofrequency or power frequency fields have been confirmed, but scientists are actively continuing to research this area. The safety of cell phone towers is the subject of extensive scientific debate. There is a growing body of scientific evidence that the electromagnetic radiation they emit, even at low levels, is dangerous to human health. The cell phone industry is expanding quickly, which is expected to increase ten-fold over the next five years. The industry has set what they say are "safe levels" of radiation exposure, but there are a growing number of doctors, physicists, and health officials who strongly disagree, and foresee a public health crisis. Studies have shown that even at low levels of this radiation, there is evidence of damage to cell tissue and DNA, and it has been linked to brain tumors, cancer, suppressed immune function, depression, miscarriage, Alzheimer's disease, and numerous other serious illnesses. Despite extensive research, to date there is no evidence to conclude that exposure to low level electromagnetic fields is harmful to human health.