DESIGN FOR OCCUPATIONAL HEALTH AND SAFETY:A BALANCE MODEL OF OCCUPATIONAL SAFETY AND HEALTH PERFORMANCE

A BALANCE MODEL OF OCCUPATIONAL SAFETY AND HEALTH PERFORMANCE

An important consideration in conceptualizing an approach to occupational health and safety is an understanding of the many personal and workplace factors that interact to cause exposures and accidents. Any strategy to control these exposures and accidents should consider a range of factors and their influences on each other. A model of human workplace interaction is presented in Figure 2. Each element of this model can produce hazardous exposures, for instance a work environment with chemical exposures. These elements also interact to produce hazardous exposures. Examples of these interactions are when high-workload tasks are performed in environments with chemical ex- posures creating greater fatigue, or more inhalation of the chemicals. Another example is when the person uses machinery and tools that have hazardous characteristics and there is high work pressure to complete the task quickly. Then, the potential for an acute injury increases. Each single factor of the balance model has specific characteristics that can influence exposures to hazards and accident potential or disease risk. At the same time, each interacts with the others to increase exposures and risks or reduce exposures and risks. The model indicates that the person is exposed to loads and hazards that create acute or chronic strains. These strains can lead directly to injury or illness, or they may increase accident potential and / or disease risk.

The Person

A wide range of individual attributes can affect exposure and accident potential. These include in- tellectual capabilities and aptitudes, perceptual–motor abilities, physical capabilities such as strength and endurance, current health status, susceptibilities to disease, and personality. A person’s education, knowledge, and aptitude affect his or her ability to recognize hazards. They also influence how much a person will learn from training about hazards and safety. An important aspect of injury prevention is to have knowledgeable employees who can determine the potential danger of an exposure and respond appropriately. This requires some previous experience with a hazard and / or training about the nature of the hazard, its injury potential, and ways to control it. Employees must have the ability to learn and retain the information that they are given in training classes. There is a fundamental need for employees to have adequate background and education to be able to apply their intelligence and acquire new knowledge through training. Of specific importance are reading and language skills

so that employees can be trained and instructed properly. When employees lack sufficient intelligence or knowledge-acquisition skills, much greater emphasis must be placed on engineering controls.

Physiological considerations such as strength, endurance, and susceptibilities to fatigue, stress, or disease are also of importance. Some jobs demand high energy expenditure and strength requirements. For these, employees must have adequate physical resources to do the work safely.

Another example deals with a concern about women being exposed to reproductive hazards in select industries, for instance in lead processing or synthetic hormone production. Biological sensi- tivity to substances may increase the risk of an adverse health outcome. Where adequate protection can be provided, there is no logical reason to exclude employees on the basis of gender or biological sensitivity. However, with certain exposures the courts in the United States have ruled that biologically sensitive employees may be barred from jobs in which these biologically adverse exposures cannot be adequately controlled or guarded against.

An attribute related to physical capacity is the perceptual / motor skills of an individual, such as eye–hand coordination. These skills vary widely among individuals and may have more health and safety significance than strength or endurance because they come into play in the moment-by-moment conduct of work tasks. While strength may influence the ability to perform a specific component of a task, perceptual / motor skills are involved in all aspects of manual tasks. Thus, perceptual / motor skills affect the quality with which a task is carried out as well as the probability of a mistake that could cause an exposure or accident.

An individual attribute that should also be considered is personality. For many years it was believed that an employee’s personality was the most significant factor in accident causation and that certain workers were more ‘‘accident prone’’ than other workers. There is some evidence that ‘‘af- fectivity’’ is related to occupational injuries (Iverson and Erwin 1997). However, in an earlier review of the accident proneness literature (Century Research Corp. 1973), it was determined that individual characteristics such as personality, age, sex, and intellectual capabilities were not significant deter- minants of accident potential or causation. Rather, situational considerations such as the hazard level of the job tasks and daily personal problems were more important in determining accident risk. There is some evidence that individuals are at greater or lesser risk at different times in their working careers due to these situational considerations. Such situational considerations may account for findings that younger and older employees have higher than average injury rates (Laflamme 1997; Laflamme and Menckel 1995).

It is critical that a proper fit be achieved among employees and other elements of the model. This can occur with proper hazard orientation, training, skill enhancement, ergonomic improvements, and proper engineering of the tasks, technology, and environment.

Technology and Materials

As with personal attributes, characteristics of the machinery, tools, technology, and materials used by the worker can influence the potential for an exposure or accident. One consideration is the extent to which machinery and tools influence the use of the most appropriate and effective perceptual / motor skills and energy resources. The relationship between the controls of a machine and the action of that machine dictates the level of perceptual / motor skill necessary to perform a task. The action of the controls and the subsequent reaction of the machinery must be compatible with basic human perceptual / motor patterns. If not, significant interference with performance can occur which may lead to improper responses that can cause accidents. In addition, the adequacy of feedback about the action of the machine affects the performance efficiency that can be achieved and the potential for an operational error.

The hazard characteristics of materials will affect exposure and risk. More hazardous materials inherently have a greater probability of adverse health outcomes upon exposure. Sometimes employ- ees will be more careful when using materials that they know have a high hazard potential. But this can only be true when they are knowledgeable about the material’s hazard level. If a material is very hazardous, often less-hazardous materials available can be substituted. The same is true for hazardous work processes. Proper substitution can decrease the risk of injury or illness, but care must be taken to ensure that the material or process being substituted is really safer and that it mixes well with the entire product formulation or production / assembly process.

Task Factors

The demands of a work activity and the way in which it is conducted can influence the probability of an exposure or accident. In addition, the influence of the work activity on employee attention, satisfaction, and motivation can affect behavior patterns that increase exposure and accident risk. Work task considerations can be broken into the physical requirements, mental requirements, and psychological considerations. The physical requirements influence the amount of energy expenditure necessary to carry out a task. Excessive physical requirements can lead to fatigue, both physiological and mental, which can reduce worker capabilities to recognize and respond to workplace hazards.

Typically, relatively high workloads can be tolerated for short periods of time. However, with longer exposure to heavy workloads and multiple exposures to shorter-duration heavy workloads, fatigue accumulates and worker capacity is diminished.

Other task considerations dealing with the content of the task that are related to the physical requirements include the pace or rate of work, the amount of repetition in task activities, and work pressure due to production demands. Task activities that are highly repetitive and paced by machinery rather than by the employee tend to be stressful. Such conditions also diminish an employee’s atten- tion to hazards and the capability to respond to a hazard due to boredom. These conditions may produce cumulative trauma disorders to the musculoskeletal system when the task activity cycle time is short and constant. Tasks with relatively low workload and energy expenditure can be very haz- ardous due to the high frequency of muscle and joint motions and boredom, which leads to employee inattention to hazards.

Psychological task content considerations, such as satisfaction with job tasks, the amount of control over the work process, participation in decision making, the ability to use knowledge and skills, the amount of esteem associated with the job, and the ability to identify with the end products of the task activity, can influence employee attention and motivation. They can also cause job stress, which can affect employee ability to attend to, recognize, and respond to hazards as well as the motivation needed to be concerned with their health and safety considerations. Negative influences can bring about emotional disturbances that limit the employee’s capabilities to respond. Task con- siderations are a central aspect in reducing worker fatigue and stress and enhancing worker motivation for positive health and safety behavior. Tasks must be designed to fit the workforce capabilities and needs and be compatible with the other elements of the model.

The Work Environment

The work environment exposes employees to materials, chemicals, and physical agents that can cause harm or injury if the exposure exceeds safe limits. Such exposures vary widely from industry to industry, from job to job, and from task to task. Hazard exposure in the work environment influences the probability of an injury or illness, and the extent of exposure often determines the seriousness. Differences in hazard potential are a central basis for determining the rates companies pay for work- ers’ compensation insurance. The central concept is one of relative risk. The greater the number of hazards, the more serious their potential to inflict injury or illness, then the greater the probability of an accident. The greater the probability of a serious accident, the higher the insurance premium. The hazard potential of different environmental factors can be evaluated using various federal, state, and local codes and standards for worker protection and limits established by scientific groups.

Environmental conditions can also hamper the ability of employees to use their senses (poor lighting, excessive noise) and reduce an employee’s abilities to respond or react to a hazardous situation. Moderate levels of noise, high levels of heat, and the presence of dust / fumes or gases / vapors have been linked to higher risk of occupational fatalities (Barreto et al. 1997). The environment should be compatible with worker perceptual / motor, energy expenditure, and motivational needs to encourage hazard recognition, precautions, and the desire to do tasks in the proper way.

Organizational Structure

A company’s health and safety performance can be influenced by management policies and proce- dures, the way that work tasks are organized into plant-wide activities, the style of employee super- vision, the motivational climate in the plant, the amount of socialization, interaction between employees, the amount of social support employees receive, and management attitude towards safety. The last point, management attitude, has often been cited as the most critical element in a successful safety program (Cohen, 1977; Smith et al. 1978; Cleveland et al. 1979). If the individuals who manage an organization have a disregard for safety considerations, then employees tend not be very motivated to work safely. Conversely, if the management attitude is that safety considerations are paramount, that is, even more important than production goals, then managers, supervisors, and employees will put great diligence into health and safety efforts.

There are other organizational considerations important in safety performance that are related to management atmosphere and attitudes. For instance, a management structure that provides for fre- quent employee interaction, positive supervisor relations, and frequent social support leads to an organizational climate that is conducive to cooperative efforts in hazard recognition and control. Such a structure also allows for the motivational climate necessary to encourage appropriate safety behavior. Supervisor and coworker social support have been shown to reduce the risk of occupational injuries (Iverson and Erwin 1997).

A consistent factor in accident causation is work pressure for greater production, or faster output, or to correct problems quickly to continue production or reduce customer waiting time. This work pressure can be exacerbated by technology malfunctions, insufficient staffing, and improper work standards. Management emphasis on reducing costs, enhancing profits, and increasing stock price often stretch the limits of the capabilities of the workforce and technology. When breakdowns occur or operations are not running normally, employees tend to take risks to keep production online or get it back online quickly. It is during these nonnormal operations that many accidents occur.

Management must provide adequate resources to meet production goals and accommodate non- normal operations. Management must also establish policies to ensure that employees and supervisors do not take unnecessary risks to ensure production.