Usage guidelines: all about performance and safety 129development used animals that had been geneticallyengineered or treated with cancer-causing chemicals so as tobe pre-disposed to develop cancer in absence of RFexposure. Other studies exposed the animals to RF for up to22 hours per day. These conditions are not similar to theconditions under which people use wireless phones, so wedon’t know with certainty what results of such studies meanfor human health.Three large epidemiology studies have been published sinceDecember 2000. Between them, the studies investigated anypossible association between the use of wireless phones andprimary brain cancer, glaucoma, meningioma, or acousticneuroma, tumors of the brain or salivary gland, leukemia, orother cancers. None of the studies demonstrated theexistence of any harmful health effects from wireless phonesRF exposures. However, none of the studies can answerquestions about long-term exposures, since average periodof phone use in these studies was around three years.What research is needed to decide whether RFexposure from wireless phones poses a healththreat?A combination of laboratory studies and epidemiologicalstudies of people actually using wireless phones wouldprovide some of the data that are needed. Lifetime animalexposure studies could be completed in a few years.However, very large numbers of animals would be needed toprovide reliable proof of a cancer promoting effect if oneexists. Epidemiological studies can provide data that isdirectly applicable to human populations, but ten or moreyears’ follow-up may be needed to provide answers aboutsome health effects, such as cancer. This is because the
