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Although many reproductive toxicants and carcinogens are used in the manufacture of semiconductor chips, and worrisome findings have been reported, no broad epidemiologic study has been conducted to define possible risks in a comprehensive way. With few exceptions, the American semiconductor industry has not supported access for independent studies. Older technologies are exported to newly industrialized countries as newer technologies are installed in Japan, the United States, and Europe. Thus there is particular concern about the many workers, mostly in countries that are still industrializing, who have jobs that use chemicals, technologies, and equipment that are no longer in use in developed countries. Since most countries lack cancer registries and have inadequate reproductive and cancer reporting mechanisms, industry efforts to control exposures to carcinogens are of particular importance. Government agencies, the courts, industry, publishers, and academia, on occasion, collude to ignore or to downplay the importance of occupational diseases. Examples of how this happens in the semiconductor industry are presented.

High-technology microelectronics has a major presence in countries such as China, India, Indonesia, and Malaysia, now the third-largest manufacturer of semiconductor chips. The migration of European, Japanese, and American companies accommodates regional markets. Low wage rates and limited enforcement of environmental regulations in developing countries also serve as incentives for the dramatic global migration of this industry. The manufacture of microelectonics products is accompanied by a high incidence of occupational illnesses, which may reflect the widespread use of toxic materials. Metals, photoactive chemicals, solvents, acids, and toxic gases are used in a wide variety of combinations and workplace settings. The industry also presents problems of radiation exposure and various occupational stressors, including some unresolved ergonomic issues. The fast-paced changes of the technology underlying this industry, as well as the stringent security precautions, have added to the difficulty of instituting proper health and safety measures. Epidemiologic studies reveal an alarming increase in spontaneous abortions among cleanroom manufacturing workers; no definitive study has yet identified its cause. Other health issues, including occupational cancer, are yet to be studied. The microelectronics industry is a good example of an industry that is exported to many areas of the world before health and safety problems are properly addressed and resolved.

This article reviews diseases that are aggravated by shiftwork (gastrointestinal and cardiovascular disorders), the potential of shiftwork to adversely affect pregnancy, shift maladaptation syndrome, and the ability of shiftwork to exacerbate existing disorders and interfere with pharmacological treatments. It offers guidelines for pre-employment screening and medical surveillance of shiftworkers.

Over the past few decades a new type of claim against workers' compensation has been steadily evolving, namely cumulative injury claims. The author examines the cost of cumulative injury claims, discusses the issue of causation, and reviews cumulative injury claims with respect to current law.

The microelectronics industry is a major user of a wide variety of chemicals and other toxic materials. In the recent past semiconductor manufacturers have located in many countries and brought a new set of challenging clinical problems to occupational physicians. California, an area with a significant history in the statistical study of health and safety in the microelectronics industry, presents some evidence of potential health hazards in the semiconductor manufacturing process. The Semiconductor Industry Study done in California in 1981 explains the application of many toxic materials in the semiconductor manufacturing process, including a variety of solvents, acids, and metals such as arsenic. The Study documents the extensive use of dopant gases, primarily arsine, phosphine and diborane. Further study is necessary to assure the health and safety of microelectronics workers, particularly in the application of dopant gases.

Since 1948, when microelectronics entered the American industrial scene, the rapid growth and advancing technology of the industry has caused production facilities to be spread throughout most industrialized areas in the United States. It is now speculated that microelectronics production will be the fourth largest industry in the United States by the end of the century. This article addresses the questions raised about the safety of this industry both for its workers and for the communities in which production facilities are located.

More than 13.5 million American workers, close to 20 percent of the work force, are assigned to evening or night shifts. In some industries such as automobile, petrochemical and textile manufacturing the proportion of shift workers is greater than 50 percent. As the popularity of shift work and other "alternative work schedules" grows, concern is increasing over the disturbance created in the lives of workers and their families by these economically and socially useful innovations. Twenty percent of workers are unable to tolerate shift work. Daily physiologic variations termed circadian rhythms are interactive and require a high degree of phase relationship to produce subjective feelings of wellbeing. Disturbance of these activities, circadian desynchronization, whether from passage over time zones or from shift rotation, results in health effects such as disturbance of the quantity and quality of sleep, disturbance of gastrointestinal and other organ system activities, and aggravation of diseases such as diabetes mellitus, epilepsy and thyrotoxicosis. Worker selection can reduce the number of health problems resulting from shift work. The periodic examination of shift workers is recommended.