Japan's mobile phone operators, NTT DoCoMo, KDDI Corporation and SoftBank Mobile Corporation have reported that radio frequency energy from mobile phone base stations does not cause damage to human cells in vitro studies.

Since November 2002, the companies have been collaborating to examine the effects of radio waves. As part of the collaboration, large-scale experiments have been conducted on the cellular and genetic level using radio waves up to 10 times stronger than the limit set forth in radio frequency radiation protection guidelines for base stations. In an interim report on April 26, 2005, the companies announced they had found no effects on cell proliferation, gene expression profile, or DNA single-strand breaks. Now they have found there are no genetic alterations or protein functions that could be associated with cell transformation or programmed cell death (apoptosis). Based on these findings, the operators have concluded that they could not find adverse health effects from radio waves from mobile phone base stations.

The World Health Organization (WHO), European and American government institutions, and Japan's Ministry of Internal Affairs and Communications (Committee to Promote Research on the Possible Biological Effect of Electromagnetic Fields) generally agree there is no firm scientific evidence that radio waves from mobile phones and base stations have adverse health effects. However, as there are some studies claiming that radio waves pose a health hazard, WHO has recommended further research on the safety of radio emissions. In response, the three mobile phone operators started examining the effects of radio waves from mobile phone systems on the human body.

Detailed studies of this joint research have been published in the annual report of the Bioelectromagnetics (BEMS) international academic society and other publications during the last three years. Three papers summarizing the results have been peer-reviewed and accepted for publication by the BEMS Journal - Sakuma et al., BEMS 27: 51-57, 2006; Hirose et al., BEMS 27: 494-504, 2006; and Hirose et al., BEMS: in press.