65 >> Health and safety informationwireless phones would providesome of the data that areneeded. Lifetime animalexposure studies could becompleted in a few years.However, very large numbers ofanimals would be needed toprovide reliable proof of acancer promoting effect if oneexists. Epidemiological studiescan provide data that is directlyapplicable to humanpopulations, but ten or moreyears' follow-up may be neededto provide answers about somehealth effects, such as cancer.This is because the intervalbetween the time of exposureto a cancer-causing agent andthe time tumors develop - ifthey do - may be many, manyyears. The interpretation ofepidemiological studies ishampered by difficulties inmeasuring actual RF exposureduring day-to-day use ofwireless phones. Many factorsaffect this measurement, suchas the angle at which the phoneis held, or which model ofphone is used.What is FDA doing to findout more about thepossible health effects ofwireless phone RF?FDA is working with the U.S.National Toxicology Programand with groups of investigatorsaround the world to ensure thathigh priority animal studies areconducted to address importantquestions about the effects ofexposure to radio frequencyenergy (RF).FDA has been a leadingparticipant in the World HealthOrganization internationalElectromagnetic Fields (EMF)Project since its inception in1996. An influential result ofthis work has been thedevelopment of a detailedagenda of research needs thathas driven the establishment ofnew research programs aroundthe world. The Project has alsohelped develop a series ofpublic information documentson EMF issues.FDA and CellularTelecommunications & InternetAssociation (CTIA) have aformal Cooperative Researchand Development Agreement(CRADA) to do research onwireless phone safety. FDAprovides the scientificoversight, obtaining input fromexperts in government,industry, and academicorganizations. CTIA-fundedresearch is conducted throughcontracts to independentinvestigators. The initialresearch will include bothlaboratory studies and studiesof wireless phone users. TheCRADA will also include a broadassessment of additionalresearch needs in the context of