3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item The usefulness of task-based exposure data incharacterising work tasks that produce potentially high short-term exposures(2009-06-01T07:50:28Z) Chester, Sean JohnIntroduction: Single sample TWA samples collected over an 8-hour shift have the potential to mask elevated exposures, excursions or “peaks” that may have occurred thus permitting situations where workers are over-exposed or indeed over-dosed. The objectives of this study, undertaken in a small acrylic sheet manufacturing plant, are therefore to identify tasks that have the potential to exceed short-term occupational exposure levels and then simultaneously monitor employees undertaking these tasks for 8-hour TWA and Short-Term exposure concentrations. The results obtained from this sampling are then compared to their respective legal limits and then finally correlated to establish their statistical significance. Materials and Methods: The study setting comprises a syrup room wherein two employees are assigned per shift. Employees in this setting manufacture an acrylic “syrup” which is achieved by dosing raw materials into any one of 13 mixing vessels. Whilst mixing, these vessels also heat the ingredients until the required viscosity is reached. This “syrup” comprising mostly of liquid methyl methacrylate, is then decanted into a pressure vessel from where it is pipe-fed into a casting chamber and finally poured between two glass sheets. When cured, the final product is stored and sold as a clear or tinted acrylic sheet. All operations with this area are therefore associated with facilitating the syrup manufacture. Personal 8-hour TWA and Task- Based measurements of methyl methacrylate vapour were simultaneously obtained from the breathing zones of six employees over five separate shifts. These employees routinely work within the setting and also undertake tasks that have the potential to exceed the Short-Term Occupational Exposure Limit (ST-OEL) for methyl methacrylate vapour. Tasks were studied and those selected for quantitative monitoring were captured using a qualitative risk assessment tool. These selections were based on studying each task to establish the employee’s exposure probability and severity i.e. whether performing the task could indeed lead to excessive Short-Term exposures. Eight-hour TWA monitoring was undertaken using activated carbon 3M 3500 passive monitoring badges which were attached to each of the subject’s breathing zone and left over 80 % of the shift. The task-based measurements were obtained by using a Drager PAC III electro-chemical monitoring instrument, which was also placed in each each 4 subject’s breathing zone, and provided real-time exposure data whilst the employees were undertaking the various tasks. Results: All measurements (N = 116) were obtained over a series of 5 full-shift monitoring periods. When analysed, 8 of the 10 of the TWA samples returned results that were below the 8-hour TWA OEL. Of the 106 task-based measurements obtained for the nine identified tasks, when averaged, 89.1 % of results exceeded the ST-OEL. When the TWA and ST measurements were correlated, only one of the nine tasks were statistically significant in their correlation. This correlation coefficient was however highly statistically significant (r = 0.339, p = 0.032 and r = 0.337, p = 0.022 respectively). Both negative and positive correlations were obtained however these were statistically insignificant. Discussion: A significantly higher proportion of the sample results were above the STOEL than the 8-hour TWA OEL concentrations contributing to the argument that ST exposure monitoring may add additional insight to employees’ exposure profiles. A major limitation of the study is however the small sample size, which makes it difficult, due to inter-worker variability amongst other factors, to extrapolate the results and their corresponding interpretations to larger, more generalised occupational hygiene monitoring scenarios. Conclusion: The results obtained therefore support the assertion that the inclusion of short-term monitoring is important in characterising employee exposures in situations where these tasks are themselves potential sources of significant chemical exposures. Recommendations: As a basis for undertaking any form of monitoring and particularly in settings where short-term, task-based exposures may exist, the importance of undertaking a systematic approach to hazard identification and risk profiling via the use of a known risk assessment tool to compile a air sampling programme, has been demonstrated in the results of this research. Further research that specifically addresses the problem of characterising workplace exposures would be useful in larger study populations as well as occupational settings which expose employees to the various types of airborne contaminant e.g. fume, mists, particulates and gases.Item Kantian distributive justice and low absolute earnings of workers(2007-02-26T13:49:21Z) Laird-Smith, StuartMany individuals working in South Africa earn extremely low wages. I briefly discuss these low wages, and examine their implications for the shareholders (owners and controllers of businesses) in South Africa. I argue that shareholders, in particular, have a moral duty to increase the absolute level of the wages of their lowest paid workers. In this essay I choose to develop this position in the context of Kantian distributive justice. I seek to join distributive justice and Kantianism together to evaluate the moral status of the lowest paid workers. I propose a just means of allocating the benefits of wages according to the work performed that shows respect for workers’ autonomy. Current South African stakeholder theory includes ‘equity’ claims arising from compensatory justice issues. However, based on the arguments in this essay, I believe we can see that there is also a definite independent moral duty in distributive justice for shareholders to increase the amounts that they spend on their worst-off employees. This spend is not necessarily only the wage costs for these employees, but is also on self-empowerment tools such as education and community services with which employees can build their life plans.Item An assessment of occupational health and safety in the informal car maintenance,welding and spraypainting industry in Mbabane.(2007-02-19T11:56:36Z) Mamba, Richard MfanaThe study was conducted in the City of Mbabane and assessed Occupational Health and Safety in the informal car maintenance, welding and spray-painting industry. The objective of the study was to assess the risks workers are exposed to in the informal car maintenance, welding and spray-painting industry in Mbabane city in Swaziland. Data was collected by administration of a questionnaire to managers of the establishments and by personal observations of workers while on the job from walk through surveys that were conducted in the city. Seventy (70) workplaces were identified and sixty five (65) of them participated in the study, representing a response rate of 92.86%. There were twenty (20) workplaces doing car maintenance, twenty five (25) doing welding and twenty (20) doing spray painting. Fifty-three (53) The data was analysed using the EPI INFO software and results revealed that most workers in this sector were indeed at high risk of exposure to occupational health and safety problems. They worked under unfavourable conditions such as working in the open and subjected to adverse weather conditions, exposed to solvents, welding fumes and gases, strenuous work, improper postures, lifting heavy loads, exposed to spray painting aerosols and fumes and exposed to dust. The workers’ occupational health and safety was made worse by the fact that most of them did not have or use personal protective equipment. 90% of the workers were exposed to emissions while carrying out their jobs of spray painting and 10% of them were exposed to paint. All the workers that were doing spray painting were exposed to paint (95%) and solvents 5%). Although 75% of the workers, doing spray painting had some kind of personal protection provided however the usage rate was very low. In all the workplaces that were doing spray painting, there were no other existing control measures for protecting the workers from paint emissions 76% did not have any respiratory protection. However, only 33.3% of them were using the PPE provided and 66.7% were not using them. Therefore most of the workers were at risk of breathing in welding fumes and other welding related gases. This means 92 % of workers were at risk to welding fumes and gases. 68% of the workers did not have protection for the hands, only 32% had. Those workers that had hand protection (32%) had gloves with shorter cuffs and separate sleeves (12%). Others had leather gauntlet gloves with canvas or cuffs (20%). 75% of these workers who had PPE were not using them, only 25% did. Since most of the workers did not use hand protection, this means that their hands were not protected against heat, spatter, and radiation. Most of the workers (72%) did not wear eye protection when removing slag and that put them at risk of eye injuries. All welding operations were not done in a booth. This means that the workers and co-workers were at risk of exposure to welding gases and fumes. 48% of the workplaces had their surroundings with materials that could catch fire. 52% had their surroundings free from burnable material. Therefore almost half of the workplaces were at risk of catching fire. 76% of the working places had no fire extinguishers. Only 24% had fire extinguishers, but only two had been serviced accordingly. The workplaces were less prepared for outbreaks of fire. 68% of the workers took no precautions against burns; they had their sleeves rolled up and forearms without gloves or sleeves when carrying out their work. Only 32% of the workers took precautions against burns. 72% of the workers said that they did not know how to treat burns. Only 28% said they knew how to treat them. 72% of the workplaces did not have first aid kits. The means that they were not prepared for accident, only 28% had first aid kits. 71.4% of the work places had first aid kits without the necessary medicines, bandages, and equipment, only 28.6% had. This indicated a lack of preparedness for accidents on their part. A long-term strategy should be developed aimed at improving the occupational health and safety of the workers. Workers need to be empowered to perform their tasks safely. Workers and owners of informal industries should participate in the formulation of interventions aimed at improving occupational health and safety. The City Council should provide health and safety education and training to the Informal Sector.