NEW FDA RESOURCE:

ernment may organize its consumer safety activities, the approximately 420 men and women who work for the Bureau of Radiological Health seem destined to have a piece of the action. A clear sign that this is likely to be the case came from Health, Education, and Welfare Secretary Elliot L. Richardson last May 25 in two related orders.

One, reassigning three former Environmental Health Service Bureaus, put Radiological Health in the Food and Drug Administration. The other made FDA responsible for HEW product safety activities. The two actions consolidated in FDA an HEW consumer safety operations base and equipped it with a major resource for consumer protection against radiation hazards.

The Bureau is that resource. This is mainly its story.

The emergence of radiation as a consumer hazard is a phenomenon of the electronics age and the vast expansion in the number, diversity, and usefulness of electronic products. Radiation today may be generated in the home by television receivers, microwave cooking ovens, or other electronic devices. Radiation sources are being introduced on waterways across the country as more boats are equipped with the new small craft radars. Radiation may be present in high school and college classrooms as more electronic devices are used in science instruction.

The greatest amount of man-made radiation exposure in the United States, however, results from largescale use of diagnostic X-ray services in the healing arts. About 130 million Americans are estimated to have had one or more X-ray examinations last year.

The public health significance of radiation from electronic products, including X-ray machines, far exceeds that from all other man-made radiation sources. In fact, X-ray ex

95 percent of man-made radiation exposure in the United States. This contrasts with less than 1 percent from radioactive discharges from nuclear power plants about which there has been so much concern.

No one questions the usefulness of electronic products. Diagnostic X-ray procedures are recognized as being among the most valuable tools of modern medicine. The potential of television for enriching the lives of millions is well understood. The contributions of electronic equipment to progress in science and industry are widely appreciated.

Authorities in the FDA Bureau of Radiological Health, however, see electronic products in an additional light: as sources of man-made radiation exposure which can and must be reduced if public health is to be fully protected. Radiation exposure reduction is the Bureau's responsibility under general and specific provisions of the Public Health Service Act. The Bureau is involved not only with electronic product radiation protection, but with reducing exposures from radioactive materials not covered by the Atomic Energy Act. Environmental radiation control, formerly a Bureau responsibility, was assigned to the Environmental Protection Agency.

The Bureau brings to FDA a body of knowledge and experience in radiation protection that the Public Health Service began to accumulate in the 1920's when it became involved in investigations of the radium poisoning of clock and watch dial painters. During succeeding decades, Public Health Service radiological health personnel acquired expertise in most aspects of manmade radiation control.

In response to rising public concern over radioactive fallout from large-scale atmospheric testing of nuclear weapons, the Public Health Service, in 1958, unified its radiation control activities. Within a few

years, radiological health had become a major program with an environmental radiation surveillance center, headquarters offices, and research laboratories in the Washington area, and three regional laboratories. Although much of the emphasis was on environmental protection, major effort also was devoted to the reduction of exposure from the use of X-ray equipment and radioactive materials in the diagnosis and treatment of disease, the conduct and support of radiation biological effects research, improvement in radiological health worker training, and the development and support of State radiation control programs. All these radiological health activities, outside the environmental field, are now carried out by the Bureau, but with stronger emphasis on electronic product radiation control.

Radiation is not easily defined. About the best definition that can be given is that it is energy moving through space as waves or invisible particles. Man has been surrounded by radiation since the beginning of his time on earth-cosmic rays from outer space and radiation from rocks and other natural sources. This is called background radiation.

There are two principal categories of radiation-ionizing and nonionizing. Ionizing radiation, such as Xrays, has the ability to strip electrons from atoms, creating ions which are electrically charged and capable of disrupting life processes. Nonionizing radiation, although lacking the ability to create ions, may adversely affect human health. Microwaves and light are examples of nonionizing radiation.

Most health effects from ionizing radiation are believed to have a linear relationship with dose. This means that either the seriousness of the effect, or the probability that an effect may occur, is believed to decline in a straight line as dose decreases. Any level of ionizing radia

by Robert T. De Vore

tion dose, however, is believed to have a potential for causing some biological damage. In other words, there is no known level of ionizing radiation dose below which it can be said that an effect may not occur and that, therefore, may be described as "safe."

A similar linear relationship between dose and effect is thought to exist for nonionizing radiation. It is not yet clear, however, whether there may be a no-effect level for nonionizing radiation.

Radiation effects are characterized as either somatic or genetic. A somatic effect is an injury to the irradiated individual and may show as a skin rash, cataract, or abnormal growth, such as cancer. Genetic effects are inheritable changes or mutations in the genetic material in reproductive cells.

Any gene damage in cells is serious. If the mutation occurs in the

genes of reproductive cells, the health defect in offspring can be magnified in future generations. The inherited genetic effects of ionizing radiation have greatly concerned radiation biological effect scientists.

The short and long-term effects of large doses of ionizing radiation are generally understood. The shortterm effects, depending upon dose, may include nausea, anemia, fatigue, blood and intestinal disorders, and loss of hair. Very high ionizing radiation doses may cause injury to the central nervous system and even death. Cancers, including leukemia, and cataracts are among the long-term effects of high doses. Among children, however, the risk of leukemia is believed to be increased by exposure to a small a small amount of ionizing radiation.

Microwaves are one of the most widely used forms of nonionizing radiation. Most microwave biological effects until recent years have been associated with energy levels sufficiently high to produce damage from heating. Recently, however, Russian and Eastern European sci

entists have reported a wide range of health effects from microwaves at levels too low to cause heat injury. Some United States scientists have been skeptical of these reports. Effects most frequently identified with microwave exposure include skin burns and eye injuries. Cataracts have been reported among U.S. workers exposed to radar, a form of microwave radiation.

In contrast to what is known about large dose radiation effects, knowledge of long-term effects of single or repeated low-level doses is far from complete. This is true for both ionizing and nonionizing radiation. Scientists agree that since safe levels of radiation dose have not been established, prudence dictates that exposure to man-made radiation should be avoided except when it can be shown that the benefit justifies the risk.

Effective application of this axiom depends upon the clearest possible understanding of risks involved in radiation exposure. Obviously, measures for the control of radiation from various electronic products, including television receivers, microwave cooking ovens, and diagnostic X-ray machines, must utilize the best available scientific knowledge of risks.

Many needs for radiation biological effects knowledge, including those associated with electronic products radiation control, have been identified by research. Much of this research has been and is being conducted either under Bureau grants and contracts or in its own laboratories.

Clearly, one of the greatest needs in radiation biology is for knowledge of the long-term effects of lowlevel radiation. One response to the need is represented by a collaborative research program, underway since 1967 at the Colorado State University at Fort Collins, to investigate long-term effects in beagles of single ionizing radiation exposures of unborn and young dogs. The

work is expected to shed important light on the relatively high radiation. sensitivity of the fetus and growing young. This kind of research cannot be rushed. It will be ten years or more before results will be known.

The recent growth in the use of such electronic products as microwave, laser, and ultrasound equipment, often involving the potential exposure of large numbers of people, has given rise to a need for increased research on nonionizing radiation effects. Among other responses to the need, the Bureau has started to investigate the ability of microwaves to cause health effects at levels too low to produce heat damage. A unique chamber for controlling research animal environments during microwave exposures was designed for this work. The ability to control temperature and such other environmental factors as

humidity, wind velocity, and atmospheric pressure and gas composition will facilitate identification of effects resulting from nonthermal microwave levels.

investigations

Several Bureau have produced significant findings about the effect of radiation in combination with other biological insults. One such study found that rats fed the chemical ethionine, a known cancer producer, developed more cancers when exposed to Xradiation. Other Bureau research established that exposures of human or animal cells to either X-rays or ultraviolet light increased the probability that they might be transformed by tumor viruses into cells predisposed to tumor formation.

To help bridge the gap between animal research and knowledge of human radiation effects, the Bureau conducts or supports epidemiologic studies of effects that may have resulted from the exposure of groups of people to known amounts of radiation. One project of this kind is investigating a possible relationship

between incidents of mental and nervous diseases and cancer and now obsolete X-ray treatments for ringworm of the scalp administered to more than 20,000 young people in Israel 10 to 20 years ago. Other research is looking for microwave health effects in a variety of exposed groups. Still another program is studying the possibility that men who have been exposed to radar may have fathered an unusual number of mongoloid children.

The Bureau's emphasis on electronic product radiation has occurred in response to the mandate of the Radiation Control for Health and Safety Act (P.L. 90-602). The act, signed by the President on October 18, 1968, directed the Secretary of Health, Education, and Welfare to establish an electronic product radiation control program. As a key part of the program, the Secretary was instructed to issue performance standards for the limitation of radiation from U.S. manufactured and imported electronic products whenever necessary for public health protection.

Responsibility for day-to-day administration of the act, including the development and enforcement of standards, was delegated to the Bureau. Until adoption of the Radiation Control Act, most regulatory authority in radiological health, other than that held by the U.S. Atomic Energy Commission, rested with local and State health authorities.

Thus, a large part of the story of radiation protection in the United States concerns the men and women who work in radiation control programs in the 50 States, the District of Columbia, Puerto Rico, the Virgin Islands, and counties and cities from coast to coast. Also involved in the action are quasi official bodies such as the National Council on Radiation Protection and Measurements and the American National Standards Institute and many professsional and industry associations.

State, Territorial, and local health

agencies are vital elements of the Nation's radiation protection resources. The Radiation Control Act requires the Bureau to work closely with the States on the development of electronic product radiation control standards to insure State-Federal program compatibility. Cooperative action has been strengthened by a number of measures, including organization of the Conference of Radiation Control Program Directors representing all State and major county or local programs.

State agencies inspect diagnostic X-ray equipment for adequacy of protective devices and provide equipment owners with expert consultation on its use and on the processing of X-ray film. In addition, some States require healing arts users of X-ray equipment to have licenses.

Model legislation has been prepared by the Bureau to aid States in establishing minimum educational and training standards for persons using radiation in the healing arts. The model law would authorize State health agencies to require certification of competence to be obtained by all users of ionizing radiation for the diagnosis or treatment of disease, including licensed physicians and dentists.

Development of the model radiation user law exemplifies a long history of Bureau assistance to nonFederal radiological health programs. For instance, thousands of beam restrictors and filters have been distributed to help reduce dental X-ray exposure, trained personnel have been assigned to assist with manpower shortages, training has been provided, radiation measuring instruments have been furnished, and X-ray equipment survey aid has been given. The States have helped with many Federal projects in return. Among the most important of these have been the 1964 and 1970 national X-ray exposure studies. Data from the 1964 study

made it possible to establish priorities for dealing with diagnostic Xray procedures as the greatest single source of man-made radiation reaching the American people. The 1970 study, when analysis of the data has been completed, will permit the assessment of present exposure reduction programs and provide guidance for such realignment of priorities as may be necessary.

Since enactment of the Radiation Control for Health and Safety Act, many radiation problems have been overcome that formerly were associated with television receivers, microwave cooking ovens, and certain electron tubes used in high school and college science instruction. Radiation control standards have been issued for each of the three kinds of products. Products covered by standards, incidentally, are required to carry compliance certification labels or tags.

Manufacturers began to to take steps to solve the TV receiver problem prior to establishment of an X-ray emissions limit under the Federal standard. Before long they had developed new circuits and redesigned components to reduce Xray generation, designed better protective shielding for tubes, improved quality testing programs, and trained service technicians to adjust sets to reduce X-ray producing capabilities.

The TV receiver standard was made applicable in three progressively more stringent phases, starting with sets manufactured after January 15, 1970. The third phase was reached on June 1, 1971. The effect of the standard is to require that sets made after last June 1 not emit X-radiation above 0.5 milliroentgen per hour under operating conditions most adverse to radiation control. To meet this requirement, manufacturers must produce sets that, under normal operating conditions, keep X-ray emissions at levels well below the limit.