Dr. Ho writes: Evidence linking weak electromagnetic radiation (EMR) to leukaemia and other cancers has been fast accumulating in recent years. Such ‘non-thermal’ effects of EMR – due to levels well below that sufficient to bring about any heating – have been observed even before World War II. During the cold war period, a four-fold excess of cancer cases was diagnosed among the staff of the American Embassy in Moscow that had been secretly irradiated with microwaves at well below the threshold set in current guidelines. The US State Department study on this episode was described in a paper published in 1997. This was among the earliest evidence for non-thermal effects of microwaves, and many studies are now confirming the high cancer risks of people exposed to microwaves from mobile phone base stations and transmitters around the world. Microwaves are no different from EMRs in the lower frequency range in that respect; except that microwaves may be even more potent in promoting cancer and other illnesses.