The future of occupational safety and health.

Pressures from 3 sources are combining to advance workplace safety and health throughout the globe. Firstly, an increasingly widespread growth in a State's interest in the individual, both in and outside the workplace. This leads to regulations, which are rapidly changing from prescriptive to enabling (performance) regulations. An increasing acceptance of sophisticated accounting procedures which will drive the real costs of poor health and safety to the bottom line of corporations. Finally, the trend to globalization, both of manufacturing and of marketing, has led to an increasing demand from consumer societies for product attributes beyond price. In many countries there is an expectation that working conditions in producing countries are not inferior to those in the consuming countries.

Measurement of slipperiness: fundamental concepts and definitions.

The main objective of this paper is to give an overview of basic concepts and definitions of terms related to the 'measurement of slipperiness' from the onset of a foot slide to a gradual loss of balance and a fall. Other unforeseen events prior to falls (e.g. tripping) are sparingly dealt with. The measurement of slipperiness may simply comprise an estimation of slipping hazard exposures that initiate the chain of events ultimately causing an injury. However, there is also a need to consider the human capacity to anticipate slipperiness and adapt to unsafe environments for avoiding a loss of balance and an injury. Biomechanical and human-centred measurements may be utilized for such an approach, including an evaluation of relevant safety criteria for slip/fall avoidance and procedures for validation of slip test devices. Mechanical slip testing approaches have been readily utilized to measure slipperiness in terms of friction or slip resistance but with conflicting outcomes. An improved understanding of the measurement of slipperiness paradigm seems to involve an integration of the methodologies used in several disciplines, among others, injury epidemiology, psychophysics, biomechanics, motor control, materials science and tribology.

Human-centred approaches in slipperiness measurement.

A number of human-centred methodologies--subjective, objective, and combined--are used for slipperiness measurement. They comprise a variety of approaches from biomechanically-oriented experiments to psychophysical tests and subjective evaluations. The objective of this paper is to review some of the research done in the field, including such topics as awareness and perception of slipperiness, postural and balance control, rating scales for balance, adaptation to slippery conditions, measurement of unexpected movements, kinematics of slipping, and protective movements during falling. The role of human factors in slips and falls will be discussed. Strengths and weaknesses of human-centred approaches in relation to mechanical slip test methodologies are considered. Current friction-based criteria and thresholds for walking without slipping are reviewed for a number of work tasks. These include activities such as walking on a level or an inclined surface, running, stopping and jumping, as well as stair ascent and descent, manual exertion (pushing and pulling, load carrying, lifting) and particular concerns of the elderly and mobility disabled persons. Some future directions for slipperiness measurement and research in the field of slips and falls are outlined. Human-centred approaches for slipperiness measurement do have many applications. First, they are utilized to develop research hypotheses and models to predict workplace risks caused by slipping. Second, they are important alternatives to apparatus-based friction measurements and are used to validate such methodologies. Third, they are used as practical tools for evaluating and monitoring slip resistance properties of footwear, anti-skid devices and floor surfaces.

Conceptual and definitional issues in occupational injury epidemiology.

This paper presents several models that further define the concept of occupational injury. While traditional models have proved successful in isolating specific research questions and health phenomena, the conceptual model presented permits a broader view of all injury morbidity. This model is based on both the level and frequency of energy transfers. A process model of occupational injury is also presented to describe the basic pathophysiological relationships associated with tissue effects/damage and recovery/repair. Numerous tradeoffs exist in variable selection, and a third model explores some of these tradeoffs. Differences in terminology and fundamental principles can limit the progress of occupational injury research. Accordingly, an argument is made for consolidation and consensus of terms. Finally, considerations for research are suggested, with an emphasis on the severity of the injury, the risk ratio, and the population at risk.

Injury and illness in the American workplace: a comparison of data sources.

Setting priorities for workplace health and safety research depends upon accurate and reliable injury and illness data. All occupational health databases have limitations when used to summarize the national scope of workplace hazards. The comparison of data from multiple sources may produce more credible estimates of the leading occupational injuries and illnesses. The purpose of this paper is to describe the strengths and weaknesses of six data collection systems that record occupational injuries and illnesses on a national level and to compare the leading estimates from these systems for 1990. The six systems are: 1) National Traumatic Occupational Fatalities database, 2) the Bureau of Labor Statistics Census of Fatal Occupational Injuries, 3) The Bureau of Labor Statistics Annual Survey data, 4) a large workers' compensation database, 5) the National Council on Compensation Insurance data, and 6) The National Electronic Injury Surveillance System. Occupational injuries, as defined herein, predominate over illnesses in terms of the number of cases and the overall costs. Databases that provide information on the antecedents of injuries suggest how these injuries may be prevented and warrant more attention and refinement.

Occupational slips and falls: more than a trivial problem.

The significance of occupational falls is established through analysis of workers' compensation data of a major insurance company. The data covered 11% of the American privately insured workforce and exposure estimates were based on Bureau of Labor Statistics demographics. The number of incidents and the relative cost of falls were examined by age, gender, industry, climate and geographic region and empirical data are presented. These data establish the enormous cost of falls measured in terms of individual pain and suffering and in losses to industrial organizations.

Research to reality: a critical review of the validity of various criteria for the prevention of occupationally induced low back pain disability.

Criteria have been suggested to reduce the incidence, or severity of low back pain disability. Five underlying theories for such criteria have been identified in the literature, and a critical review of the validity of these criteria has been carried out. Despite attributions elsewhere, peer-reviewed validation of the various criteria range from modest to nil. The need for a validation criterion for use in workplace design in order to reduce low back pain disability, or severity, is identified and the need for an international protocol to allow cross-study validation of present and future criteria is suggested.

An alternative speed control for industrial sewing machines.

Occupations which normally involve a fixed workstation and can be effectively operated from a sitting position would appear to be highly compatible with the lack of mobility of paraplegics. However, owing to the traditional operational-control configuration of many machines which require use of the lower limbs, employment for paraplegics is limited in these occupations. A speed-control mechanism suitable for use by paraplegics was designed and compared with the traditional treadle speed control used on industrial sewing machines. This control was operated by chest movement displacing a lever in contact with the subject in the region of the sternum. Subjects for this study were twenty non-handicapped individuals primarily without any previous sewing experience. Data were collected by questionnaires, anthropometric measurements, and performance on sewing tasks. There was no significant difference between the two control devices in accuracy and task-completion time. The chest-control device required significantly fewer machine stops during task performance. The chest-control device produced less overall postural stress than the traditional treadle control. Overall preference for the two control devices was divided equally among the subjects. The chest-control device will enable many of those unable to use their lower limbs to operate any one of a series of stitching-related machines by providing access to, and control of, the machine. The control device appears to provide the potential for both the handicapped and non-handicapped to achieve performance equal to that achieved by the latter group with conventional treadle controls. It is suggested that the alternative control could be used not only with industrial sewing machines, but also with other machines that require a fixed workstation and can be operated from a sitting position.

The organisation of industrial ergonomics--A human: machine model.

The multidisciplinary nature of ergonomics requires the organisation of component disciplines into a recognisable technology for industrial practice, the development of methodologies for use by ergonomists and the specification of criteria for training courses. A simple model is presented and illustrated which has been developed and used in industrial practice and in training for industrial practice.

The introduction of ergonomics: A problem of industrial practice.

The problem of introducing ergonomics into a major chemical industry was tackled by a novel approach which allowed the industry concerned access to a wide range of ergonomics skills. This allowed appropriate expertise to be applied as necessary to the variety of problems arising in the design of a plant. The problems included equipment design and layout, thermal, auditory and visual environments, job design and training aids. The difficulties of identifying the benefits of such an introduction were dealt with by the use of a senior management seminar which employed a 'paired presentation' format to describe both the various contributions made by the ergonomists to the industry and the evaluation by the individual recipients of such contributions.