frequency energy (RF) at a level that is hazardous to the user. In such acase, FDA could require the manufacturers of wireless phones to notifyusers of the health hazard and to repair, replace or recall the phones sothat the hazard no longer exists.Although the existing scientific data do not justify FDA regulatory actions,FDA has urged the wireless phone industry to take a number of steps,including the following: “Support needed research into possible biological effects of RF ofthe type emitted by wireless phones; “Design wireless phones in a way that minimizes any RF exposureto the user that is not necessary for device function; and “Cooperate in providing users of wireless phones with the bestpossible information on possible effects of wireless phone use onhuman health.FDA belongs to an interagency working group of the federal agencies thathave responsibility for different aspects of RF safety to ensure coordinatedefforts at the federal level. The following agencies belong to this workinggroup: “National Institute for Occupational Safety and Health “Environmental Protection Agency “Federal Communications Commission “Occupational Safety and Health Administration “National Telecommunications and Information AdministrationThe National Institutes of Health participates in some interagency workinggroup activities, as well.FDA shares regulatory responsibilities for wireless phones with the FederalCommunications Commission (FCC). All phones that are sold in the UnitedStates must comply with FCC safety guidelines that limit RF exposure.FCC relies on FDA and other health agencies for safety questions aboutwireless phones.FCC also regulates the base stations that the wireless phone networksrely upon. While these base stations operate at higher power than do thewireless phones themselves, the RF exposures that people get from thesebase stations are typically thousands of times lower than those they canget from wireless phones. Base stations are thus not the primary subjectof the safety questions discussed in this document.What are the results of the research done already?The research done thus far has produced conflicting results, and manystudies have suffered from flaws in their research methods. Animalexperiments investigating the effects of radio frequency energy (RF)exposures characteristic of wireless phones have yielded conflictingresults that often cannot be repeated in other laboratories. A few animalstudies, however, have suggested that low levels of RF could acceleratethe development of cancer in laboratory animals. However, many of thestudies that showed increased tumor development used animals that had