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Cellular telephones, first marketed in 1983, have become one of the fastest selling consumer electronic products. By the end of 1993, over 16 million Americans were using cellular telephones, and the industry estimates that in less than a decade, over 60 million Americans will be using a cellular communications device. About one-third of all cellular telephones currently in use are hand-held portable models, which are growing in popularity. Industry forecasters predict a high demand for a new generation of personal communications devices that will offer a greater range of uses. Technology enthusiasts envision a future in which nearly all Americans will have a wireless portable communications device.
Cellular telephones come in a variety of styles, but all fall into the following three general categories:
Telephone A is an example of the first style of hand-held portable cellular telephone; it is characterized by a bulky body and a nonretractable antenna It is heavier than most of the newer portable cellular telephones. Telephone B is an example of the flip-style" cellular telephone; it features a mouthpiece that can be folded over the keypad and a retractable antenna for storage while not in use. Telephone C is an example of a nonflip-style telephone; it has a shorter nonretractable antenna. Telephone D is the newest style of portable cellular telephone; it is designed to transmit and receive digital signals.
All devices that transmit radio signals - such as radio broadcast towers and cellular telephones - emit radio- frequency radiation. Radio-frequency radiation is electromagnetic energy emitted in the form of waves. Cellular telephones transmit voice messages by sending electronic signals from an antenna over radio waves at frequencies between 824 and 894 megahertz (Mhz) . These signals are a form of radio-frequency radiation.
At sufficient power levels, radio-frequency radiation can heat body tissue and cause biological damage such as burns. These effects of exposure to radio-frequency radiation, called thermal effects, are immediately observable. According to the 1982 American National Standards Institute's (ANSI) standard for radiation exposure , a nongovernment standard that some federal agencies use, devices operating on 7 or less watts of power at frequencies below 1,000 MHz will not produce immediate thermal effects. Portable cellular telephones operate on well below 7 watts of power. They use up to a maximum of 0.6 watts of power, less than the amount of power required to light a flashlight bulb. However, questions have been raised about whether long-term or frequent exposures to low levels of radio-frequency radiation have other biological effects that are delayed or not immediately observed in human cells and animals.
Portable cellular telephones transmit messages to a cellular transmitter tower. More power is required to transmit a signal when the telephone is farther away from a tower. For example, if a caller is located at a great distance from the tower, the telephone may use the full 0.6 watts of power to transmit the signal. However if the caller is near the tower. the telephone may only need to use about 0.2 watts of power to transmit the signal.
Cellular telephones transmit either analog or digitized voice messages, depending on the type of cellular telephone used and the service available. In analog radio communication systems, messages are transmitted by modulating, or varying, either the amplitude (height) or the frequency (number of wave crests) of the radio wave. In digital communication systems, messages are transmitted as a series of digits in rapid bursts, or pulses. These are sometimes referred to as pulse-modulated signals. An advantage of digital transmission is that it increases channel capacity by allowing several users to transmit messages over the same radio wave simultaneously. As the figure shows, analog signals are continuous radio waves, while digital signals are binary usually represented by ones and zeroes. (See appendix I for additional information on these two technologies.)
The next generation of cellular communications is called personal communications services. In this system, inexpensive, pocket-sized communications devices that use digital technology will deliver voice, data, and images. They will operate at higher radio frequencies (between 1,850 and 2,200 MHz) and will likely use less power to operate than the current generation of portable cellular telephones. A personal communications device carried from place to place will enable the person to be reached at any location by dialing a single telephone number. Because personal communications services devices are still under development, it is not clear whether the antenna will be in close proximity to the user's head when the device is in use.
Three federal agencies play a role in ensuring the safety of cellular telephones by sharing responsibility for regulating devices that emit radio-frequency radiation and protecting the public from exposure to radiation: the Food and Drug Administration (FDA), the Environmental Protection Agency (EPA), and the Federal Communications Commission (FCC).
Under the Radiation Control for Health and Safety Act of 1968, as amended, FDA is responsible for establishing and carrying out a program, designed to protect public health and safety, to control radiation from electronic products. These responsibilities include (1) developing and administering performance standards for electronic products; (2) planning, conducting, coordinating, and supporting research, development, training, and operational activities to minimize the emissions of, and exposure of people to, unnecessary radiation from electronic products; and (3) developing, testing, and evaluating the effectiveness of procedures and techniques for minimizing exposure to electronic product radiation. FDA has the authority to set performance standards for electronic products if it determines that such standards are necessary for the public health and safety. In carrying out its responsibilities, FDA reviews and comments on industry research and also works with electronic product manufacturers when it receives complaints or has some concerns about a product but lacks sufficient scientific evidence to determine if a performance standard is necessary. Consistent with the principle of keeping exposure "as low as reasonably achievable," FDA has worked with a variety of manufacturers to reduce radiation emissions. For example, FDA has worked with manufacturers of video display terminals and police radar devices to address concerns about excessive exposure to radiation and with manufacturers of electric blankets to redesign the blankets to reduce electric and magnetic fields.
Under the Federal Radiation Council Authority, transferred to EPA by Reorganization Plan No. 3 of 1970, EPA is responsible for, among other things, advising the President on radiation matters, including providing guidance for all federal agencies on formulating protective standards on radiation exposure. Upon presidential approval of EPA's recommendation on formulating standards, the pertinent federal agencies would be responsible for implementing the guidance. Under the National Environmental Policy Act of 1969 (NEPA), FCC is required to consider whether its actions - including actions that may lead to human exposure to radio-frequency radiation - in authorizing communications equipment significantly affect the quality of the human environment.
The Chairman of the Subcommittee on Telecommunications and Finance, House Committee on Energy and Commerce, requested that we review (1) the status of scientific knowledge on the potential health risks of radio- frequency radiation emitted by portable cellular telephones and federal involvement in any related research and (2) the actions of the responsible federal agencies to ensure the safety of portable cellular telephones and similar communications devices.
To assess the status of scientific knowledge on the health risks of portable cellular telephone use, we met with scientists who have conducted research on cellular telephones and visited industry, university, and government laboratories where research is taking place. We met with scientists and researchers in the field of electromagnetic radiation at the Department of Defense, EPA, FCC, FDA, and the National Academy of Sciences. (See appendix 2 for a list of the researchers and scientists we consulted for this report.) We also obtained the opinions of many federal agencies with representation on the Committee on Interagency Radiation Research and Policy Coordination within the Executive Office of the President.
We discussed the safety of portable cellular telephones with the president of the Bioelectromagnetics Society; the co-chairs of a subcommittee established by the Institute of Electrical and Electronics Engineers, Inc., which set the latest exposure standard for radio-frequency radiation exposure; and a vice-president of Motorola, Inc., a leader in cellular telephone research. In addition, we met with of officials from the National Council on Radiation Protection and Measurements and the Cellular Telecommunications Industry Association.
We collected information on regulatory actions regarding the safety of portable cellular telephones from the responsible federal agencies. We discussed with FCC of officials the actions they have taken to ensure the safe use of cellular telephones. We examined FCC's records and rulemakings on the agency's process for authorizing portable cellular telephones and FCC implementation of requirements under NEPA. We discussed with FDA officials their procedures for setting performance standards for electronic products and their plans for cellular telephones. Finally, we discussed with EPA officials, and reviewed documents on, EPA's efforts to develop federal guidance for setting standards for human exposure to radio-frequency radiation. We conducted our review between March 1993 and October 1994 in accordance with generally accepted government auditing standards.