National Occupational Research Agenda

Work Environment and Workforce

Five of the NORA priority areas fall in the category of work environment and workforce. Although seemingly very different, the research priorities represented here underscore the importance of the markedly changing nature of work--and who does it--in the United States today. Research is needed to understand the complex interactions between traditional risk factors and the various social and economic forces that operate within special populations at risk (e.g., older workers, adolescents, and minorities). Emerging technologies pose the challenge to anticipate and prevent the hazards with which they may be associated. Large numbers of office workers complain of symptoms related to the indoor environment, but ready diagnosis and control of these problems have been elusive. Most research in the field has targeted single exposures, but there is little understanding of the harmful interactions of mixed exposures (more than one chemical or physical agent). Aspects of the organization of work are increasingly recognized but little understood as risk factors for injury and illness and as threats to organizational efficiency and productivity.

Emerging Technologies

Advances in technologies provide opportunities to minimize the drudgery of work and to eliminate old hazards, but they may also create new, currently unrecognized risks to workers. Mechanisms are needed to anticipate the potential adverse health consequences of these technologies. Also needed are laboratory and statistical models to predict hazards, and surveillance systems that rapidly identify worker morbidity and mortality associated with new materials, tools, or processes. As emerging hazards are identified, the challenge shifts to development and application of effective control measures.

Importance

In highly competitive economies, the fast-paced development of new and improved products and services inevitably spurs the development of new technologies (new materials, tools, and processes). A major challenge facing occupational safety and health researchers and practitioners is the timely identification of emerging technologies to (1) assess their potential to cause harm to workers, (2) evaluate specific work sites, (3) develop effective control strategies where occupational hazards exist, (4) identify superior new technologies that diminish risk and (5) share information for the benefit of all persons at risk and those responsible for managing the risk. Ideally, workplace safety and health can become a key element in the design of new technologies in contrast with the more common approach of developing controls after a problem is identified.

One promising approach for identifying the potential hazards of emerging technologies is to examine those sectors of the economy that produce rapid growth and thereby drive innovation. A list of the 500 fastest-growing U.S. technology companies includes not only large corporations but also many small start-up companies. Nearly three-fifths of these rapid-growth companies are in information technology/telecommunications; about one-fifth are in the biotechnology/medical sector; and most of the others are roughly split (about 8 % each) between the manufacturing/materials and the instrumentation/electronics industries.

Programs such as the NIOSH Health Hazard Evaluation Program (HHE) and the Occupational Safety and Health Administration State Consultation Program are useful for identifying safety and health issues associated with evolving technologies. These programs have identified potential hazards related to new technology or new applications of existing technology. For example, they have found the following:

Although sodium azide is not new, its production and associated explosion hazards have increased with recent requirements for automobile air bags. The new industry of recycling small household batteries (to reduce levels of mercury in landfills) is exposing workers to hazardous levels of mercury, a neurological poison. The cleaner-burning, reformulated (oxygenated) fuels now required by the U.S. Environmental Protection Agency in more than 100 areas of the United States are resulting in reports of respiratory irritation by service station attendants.

Research Opportunities

Research must address the challenge of predicting hazards associated with emerging technologies and modifying the risks to workers. Improved statistical tools and laboratory models are needed to generate predictive approaches for potential hazards before commercialization of new technologies. As new hazards are identified and characterized, substitutions or appropriate and effective control measures can be developed. To detect unanticipated morbidity and mortality patterns in workers using new materials and processes, improved surveillance systems are needed. These systems should include the use of workers' compensation and insurance data. Regional data collection from sources such as health maintenance organizations in high technology areas--Silicon Valley in California or the Route 128 Corridor near Boston--might also prove effective. The inclusion of safety and health principles in all stages of the development of new technologies (including concept development, engineering, production, and marketing) must be promoted. An overall systematic procedure for identifying, reviewing, and selecting new technologies for potential intervention will need to be developed by partnerships involving trade associations, national laboratories, universities, government agencies, labor unions, and industry consortia. Early identification and communication of information about hazards associated with emerging technologies will allow anticipation of potential exposure problems and development and assessment of new prevention strategies.

Indoor Environment

Since the energy crisis of the 1970s, a persistent epidemic of health complaints has appeared among workers in nonindustrial work environments. Reported problems have ranged from allergic and infectious diseases to nonspecific symptoms such as headaches and eye irritation. Current evidence suggests that better solutions to such problems will be possible with additional research efforts, including the development of improved measurement methods (particularly for microbiologic and chemical exposures), systematic clinical approaches to diagnosis and treatment, building maintenance and operation approaches, and, innovative multifaceted effective intervention strategies.

Importance

Traditionally, indoor nonindustrial occupational environments such as offices have been considered clean and relatively free of contaminants. In the last 20 years, however, reports of symptoms and other health complaints related to these indoor environments have been increasing. In some cases, recognized infectious or chronic diseases (such as Legionnaire's disease or hypersensitivity pneumonitis) have been diagnosed and attributed to improper design, operation, or maintenance of buildings. Yet the majority of health problems reported in buildings (namely, nonspecific complaints sometimes called sick building syndrome) cannot yet be attributed to specific exposures. Available evidence suggests that multiple factors are involved, including microbiological and chemical exposures not adequately characterized by current exposure assessment approaches; physical conditions such as temperature, humidity, lighting and noise; and social/psychological stressors.

More than half the U.S. workforce is employed indoors, and estimates of the proportion of indoor workers affected by these problems range up to 30%. Among the requests received annually by NIOSH for occupational health investigations, the proportion related to indoor nonindustrial environments has increased over the years, from 2% in 1980 up to 35% to 65% in recent years.

Although only a small proportion of the estimated 20 to 30 million U.S. workers who experience health problems may be seriously impaired, the large absolute numbers make the associated economic costs high. These are estimated by some at tens of billions of dollars per year, including the costs of health care and absenteeism, reduced worker productivity, building investigations and building improvements. These costs do not include the enormous costs of closure or renovation of many buildings each year in attempts to solve these problems. Furthermore, the office and indoor job sectors continue to expand along with the proportion of modern, energy-efficient buildings in which these health problems tend to occur.

Research Opportunities

A variety of research strategies will be necessary to identify adverse indoor exposures or conditions, characterize exposure and health effect relationships, and develop effective preventive measures. Intervention studies can identify appropriate building design, maintenance, and operation strategies to prevent indoor-related health problems, even before identification of specific causal exposures. Promising interventions include improving air filtration for contaminants and improving cleaning methods for indoor surfaces.

Epidemiologic studies can identify indoor exposures (whether microbiological, chemical, physical, or social/psychological) associated with adverse health outcomes. Improved, objective measurement methods for relevant health outcomes (including irritant or immunologic as well as infectious diseases) are crucial in the efficient identification of adverse exposures. Improved field and laboratory methods are necessary for measuring and interpreting complex indoor exposures. Particular challenges exist in assessment of viable and nonviable microbiological exposures, which may act through allergenic, irritant, or infectious mechanisms. Methods for accurate characterization of low-level complex chemical exposures are also needed. Such research strategies in indoor environments are essential to improve understanding and prevention of both recognized, building-related illnesses and nonspecific indoor-related symptom complaints.

Mixed Exposures

Agricultural, industrial, and other workers are commonly exposed to combinations of chemical or physical agents, but knowledge about the potential health effects of mixed exposures is limited. New approaches are needed to identify synergistic effects of multiple exposures, to better characterize the exposures of workers, to improve laboratory and statistical analysis methods, and to develop hazard controls that take into account the components in the mixture.

Importance

Workers are commonly exposed to multiple agents, either as mixtures of agents or as separate simultaneous exposures. For example, farm workers are exposed to multiple chemicals in pesticides, and welders face exposures to welding fumes from electrodes and flux materials. However, little is known about how individual agents in mixed exposures may interact to increase or otherwise modify the likelihood of adverse health effects.

Research has shown that physiologic interactions from some mixed exposures can lead to an increase in the severity of the harmful effect. For example, exposure to noise and the solvent toluene results in a two- to three- times-higher risk of hearing loss than exposure to either component alone (see figure). The problem is multifaceted, given the large number of different types of mixed exposures that occur every day in a variety of workplaces.

Examples of mixtures with potentially harmful interactions include solvent and pesticide mixtures, diesel and other fuels, indoor air, asphalt, irritants on dust, and hazardous waste. Examples of simultaneous mixed exposures include combinations such as welding fumes and nitrogen oxide compounds, radiation or noise and solvents, and asbestos and cigarette smoke. In most of these cases, too little is known about the combined exposure-response relationships to recommend new exposure limits or to plan effective exposure controls or interventions.

Research Opportunities

Research on mixed exposures can proceed in several directions and would benefit from interdisciplinary teams of investigators. To evaluate possible synergistic effects, laboratory studies of physiologic interactions at the target organs are needed, as are improved animal models for extrapolation to humans. Advances in molecular biology may permit new laboratory approaches to determine which agents within a mixture are hazardous and to evaluate substitutes. Improved field methods are needed to characterize simultaneous exposures of workers. The combined tools of molecular biology and epidemiology can be used to assess worker exposures to individual agents as well as to identify biologic changes or health effects that may result from exposures. Statistical data analysis methods that have been applied to the mixed exposure problem (such as cluster analysis, pattern recognition, regression trees, and other multivariate methods) need to be improved. Such research strategies will lead to greater understanding of synergistic interactions, better controls for mixed exposures, and appropriate exposure limits for some mixed exposures.

Organization of Work

Organization of work refers to the way work processes are structured and managed. In addition to the long recognized job stress associated with aspects of work organization, studies are now identifying its contributions to other diverse health problems, including musculoskeletal disorders and cardiovascular diseases. Research is needed to better understand how work organization is being influenced by the changing economy and workplace and what the potential effects are on worker safety and health. Research opportunities include surveillance, etiologic studies of risk factors and intervention strategies to mitigate adverse work organization factors and outcomes.

Importance

The expression "organization of work" or "work organization" has come into increasing usage in the field of occupational health, but it lacks precise definition. In general, work organization refers to the way work processes are structured and managed, and it deals with subjects such as the following: the scheduling of work (such as work-rest schedules, hours of work and shift work), job design (such as complexity of tasks, skill and effort required, and degree of worker control), interpersonal aspects of work (such as relationships with supervisors and coworkers), career concerns (such as job security and growth opportunities), management style (such as participatory management practices and teamwork), and organizational characteristics (such as climate, culture, and communications).

Many of these elements are sometimes referred to as "psychosocial factors" and have long been recognized as risk factors for job stress and psychological strain. But recent studies suggest that work organization may have a broad influence on worker safety and health and may contribute to occupational injury, work-related musculoskeletal disorders, cardiovascular disease, and other occupational health concerns such as indoor air quality complaints. For example, work organization factors such as monotonous work, time pressure, and limited worker control have been linked to upper-extremity musculoskeletal disorders in a number of studies. Similarly, it is widely believed that the combination of low worker control and high job demands is a risk factor for cardiovascular disease. However, the manner in which work organization factors affect these types of health problems is not well understood.

Work organization is influenced by factors such as economic conditions, technologic change, demographic trends, and changing corporate and employment practices. Information and service industries are replacing manufacturing jobs. The workforce is aging rapidly and becoming increasingly diverse. Re-engineering and downsizing continue unabated, and temporary or part-time jobs are increasingly common. These trends may adversely affect work organization and may result, for example, in increased work load demands, longer and more varied work shifts, and job insecurity. However, the actual effects of these trends on the conditions of work and on the well-being of workers have received little study.

Research Opportunities

Today's rapidly changing economy, with widespread corporate and government restructuring, has thrown the once low-profile issues of work organization into high relief. If a factory or service operates around the clock to maximize productivity or attend to customer needs, what strategies will both assure productivity and prevent the adverse effects of night or extended shifts on injury rates or sleep disorders? What management approaches translate employer and employee concern about safety into actions that effectively prevent injury? What impact does the holding of multiple jobs (an increasingly common effect of low pay) have on workers' health and health care utilization? How does it affect an industry's injury or illness rates? What biologic measures would indicate whether an employee's increased work load or reduced control over work is increasing his or her risk of cardiovascular disease? How do 12-hour work shifts or "de-skilling" of certain jobs affect rates of sick leave, employee turnover, workers' compensation, and health care costs? How can such costs be avoided? The limited research invested in work organization has outlined a whole host of issues. Scientists need to establish ways of identifying industries, occupations, populations, and specific worksites needing evaluation and assistance. Definitive research is needed to clarify the relationship between psychosocial stressors associated with work organization and safety and health concerns ranging from substance abuse to musculoskeletal disorders. Also, a wide range of research is needed to identify successful interventions and models of work organization that promote safety and health and that meet current and future demands for increasing productivity.

Special Populations at Risk

Occupational hazards are known to be distributed differentially, and workers with specific biologic, social, and/or economic characteristics are more likely to have increased risks of work-related diseases and injuries. The relative proportions of these special populations (such as older workers, women, and minorities) within the U.S. workforce are increasing, and it is important to focus on these populations, particularly as they have been largely underserved in the past. Research is needed to define the nature and magnitude of risks experienced and to develop appropriate intervention and communication strategies.

Importance

Certain populations of workers are more likely to experience increased risks of diseases and injuries in the workplace as a result of biologic, social, and/or economic characteristics such as age, race, genetic susceptibility, disability, language, literacy, culture, and low income. Specific directed efforts are needed to prevent work-related diseases and injuries in these special populations. As the U.S. workforce grows by the year 2005 to approximately 147 million (a 12% increase over the number of workers in 1994), it will become markedly older and more racially diverse. The number of workers aged 65 and older was 3.7 million in 1995. The number of workers aged 55 and older is expected to grow twice as fast as the total workforce for the next several years as the "baby boomer" population matures and life expectancy increases. Partly because of the passage of the Americans with Disabilities Act of 1990 (ADA), barriers are also being removed to allow people with disabilities to participate more fully in the workplace. In addition, by the year 2005, minorities will represent 28% of the American workforce compared with 24% in 1994. This figure will include the increase of the fastest growing sector, Hispanic workers, who will constitute 11.1% of the workforce in 2005 compared with 9.1% in 1994.

Older workers are at greatly increased risk of work-related injury fatalities. In 1993, the rate of fatal traumatic injuries was 15 per 100,000 workers aged 65 years and older compared to 5 per 100,000 workers aged 25 to 34. Older workers may also be more susceptible to chronic diseases. There were approximately 2.6 million working adolescents (aged 16 to 17) in the United States in 1995. Younger workers are at increased risk of work-related injury because they often have limited job knowledge, training, and skills. Private industry reported that in 1993, more than 95,000 illnesses and injuries that involved days away from work occurred in workers aged 16 to 19. An estimated 64,000 adolescents required treatment for work-related injuries in emergency rooms during 1992. The most serious of these injuries were burns occurring in the food service industry and sprains and strains due to overexertion. In addition, the number of children (aged less than 16) who are working and the illnesses and injuries they experience are not well documented. The best documented examples are childhood traumatic injuries on the farm. However, less well-documented reports exist of injuries to children illegally employed in various manufacturing settings. Physical and psychosocial factors may also place young workers at increased risk of injury in the workplace, and children and adolescents, along with older workers, may have increased or different susceptibilities to chemical exposures.

Although the nature and magnitude of risks experienced by people of color have not been thoroughly studied, data on occupational injury deaths indicate that blacks have the highest rates per 100,000 workers compared with those of whites and workers of other races. Data on mortality (not necessarily occupationally induced) have consistently demonstrated higher cancer and overall mortality rates for blacks than for whites. In the limited number of occupational studies that can assess cancer risks in both white and black men, the latter were twice as likely to demonstrate significant excesses of cancer. Environmental justice issues are also important, as initial research indicates that workers of color or low income may disproportionately work in unsafe and unhealthful conditions without appropriate notification of risks, training, or protection.

Little is known about a number of other factors that may increase the risk for occupational disease and injury, including the role of gender, genetic susceptibility, culture, and literacy. Many high-risk populations have been underserved by the occupational safety and health research community, with the result that important unanswered questions remain about the profile of hazards they face, the incidence of work-related injuries and illnesses, the mechanisms of these injuries and illnesses, and the optimal approach to prevention.

Research Opportunities

Scientists are only beginning to recognize the full range of biologic and social factors that may influence a worker's risk for developing disease or becoming injured in the workplace. Research is needed to determine where special populations at risk are working, the conditions of work, and the extent and severity of disease and injury among these workers. This information is especially elusive for migrant and seasonal workers, day laborers, part-time workers (including working youth), and self-employed contract and temporary workers. The assessment of the impact of susceptibilities on the development of effective interventions will be challenging. Little is known, for example, about the physical resilience and capacity of older workers or the effectiveness of traditional workplace safeguards for workers with disabilities. The development of reliable exposure histories is difficult for transient workers or workers living and working in contaminated environments. Research is needed on the interaction between psychosocial stressors (such as low pay and racial conflict) and other work factors such as musculoskeletal stressors or safety practices. The development of intervention prevention strategies will undoubtedly require innovative approaches. How is a hearing-impaired construction worker alerted to safety hazards? What training and communication approaches and other prevention strategies are most effective for workers for whom English is not a native language or who have limited reading ability, or for workers of different races, ages, cultures, and socioeconomic circumstances? How should rehabilitation strategies be tailored for different populations? Research is also required for intervention approaches that address issues of genetic susceptibility; such research should consider ethical issues such as the societal, economic, and health consequences of screening and potentially excluding susceptible populations from employment.