Heat stress occurs when the body cannot adequately cool itself due to the combined contributions of metabolic heat, environmental factors and clothing. Heat stress found in the workplace puts employees at risk of developing heat-related illnesses, disorders and could be fatal. The wet bulb globe temperature (WBGT) index is the current method used to assess environmental contributions to heat stress in an occupational setting. The purpose of this thesis was to explore whether the National Weather Service's Heat Index (HI) could substitute for the WBGT Index during occupational heat stress exposure assessment. The possibility of using the HI for heat stress exposure assessments was explored by first developing an occupational exposure limit based on the HI and then by comparing the HI to WBGT Index over a range of environments. Data from 10 selected studies were reviewed and categorized into two groups (Classic Data and Progressive Data) based on the method used to determine the upper limit of the prescriptive zone. WBGT and HI values were estimated from the environmental data provided in the 10 studies and the metabolic demands were also noted. These data were used to illustrate the relationship between environment (WBGT and HI) and metabolic rate. Next the relationship between HI and WBGT was compared over a range of environments consisting of combinations of air temperature and percent relative humidity as defined by the NWS's Heat Index Chart. Finally the effects of adding a high radiant heat load (Tg = Tdb+10 °C) to the relationship between WBGT and HI was explored. The HI occupational exposure limits were protective of the upper limit threshold points in a manner similar to WBGT. A greater spread in the Classic and Progressive upper limit data was observed above the occupational exposure limit when expressed as HI. High correlation was observed (R2 = 0.95) between the WBGT Index and HI over a range of environments, assuming no radiant heat. The incremental increase in HI due to high radiant heat indicated a strong dependency on the absolute value of HI, which makes using HI to predict WBGT in radiant heat environments problematic. Findings suggest the Heat Index could be used to assess heat stress exposures and to set occupational exposure limits for hot environments in the absence of high radiant heat.

Graduation date: 1994

Clothing can influence heat stress depending on the design and its ability to act as a barrier. The progressive heat stress protocol permitted the collection of data to empirically estimate the apparent total evaporative resistance (Re,T,a). Five different clothing ensembles were evaluated, which included work clothes, cotton coveralls, and three limited-use protective clothing ensembles including a pthesis-barrier ensemble, (Tyvek® 1424), water-barrier, vapor-permeable ensemble (NexGen® LS 417), and a vapor-barrier ensemble (Tychem QC®). The study design called for three metabolic level's: low, moderate, and high (L, M, & H) and three heat stages: compensable, transitional, uncompensable (C, T, U). The purpose of this study was to determine if Re,T,a values remained constant over a range of metabolic and heat stage levels. Calculated Re,T,a values were compared using a four-way mixed model analysis of variance. Significant differences for Re,T,a were found among ensembles, metabolic levels, heat stress stages, as well as interactions among ensembles and metabolic levels along with ensembles and heat stress stages (p < 0.0001). A Tukey's Honestly Significant Difference multiple comparison test identified where significant differences occurred (p < 0.05). Results show Re,T,a values differ over a range of metabolic levels and stages of heat stress. Additionally, convection is more supportive of evaporative cooling than diffusion.

Because of their relative inexperience in performing procedures and handling sharps devices, medical students and resident physicians are considered to be at high risk for sharps injuries. A higher rate of sharps injuries for medical trainees implies a higher risk for occupationally-acquired infection with bloodborne pathogens and may have financial and legal implications for training institutions. This study examines the prevalence of sharps injuries among US medical students and resident physicians. A systematic review of the literature yielded 10 studies that gave data on sharps injuries for US medical students or residents, and those data were combined with data from our institution to produce pooled prevalences. Results from our institution showed that residents had a significantly higher risk of sharps injuries than medical students. While sharps injuries increased with students' years of training, residents' rates decreased with increasing level of training. Resident rates were highest in the department of Surgery and lowest for Pediatrics. Comparing pooled prevalences of US trainees revealed that residents were 6 times more likely than medical students to have a sharps injury. This information can be used by training programs to inform changes in residency training curricula and infection control policies, as well as to forecast Worker's Compensation and long-term disability insurance coverage requirements. Medical training institutions must continue to provide opportunities for students and residents to perfect their procedural skills, but at the same time, trainees must be protected from the risk of sharps injuries and exposure to bloodborne pathogens.

Outdoor workers are often subjected to thermal conditions beyond the comfort zone, but to what degree do such conditions affect the health and safety of those workers is still a matter requiring further investigation. The purpose of this study is to examine the relationship between thermal conditions and (1) heat-related disorders and (2) acute injuries using injury and illness data collected during the BP Deepwater Horizon clean-up operations. Over an eleven month period, 5,485 cases were identified as either heat-related or an acute injury (incident type) and further divided by severity. Daily weather data were used to estimate the wet bulb globe temperature (WBGT) based on the time of day. Heat Stress Levels intervals were defined using the estimated WBGT. Labor-hours by month were estimated by the prevailing shift length in the month and the number of workers. The incidents were assigned a Heat Stress Level and the number of labor-hours by heat stress level were determined. The next step was to calculate the incident rate ratio by Heat Stress Level against the baseline of thermal comfort. The results indicated that the rate ratios for heat-related disorders and acute injury increased for thermal conditions from 24⁰C-WBGT to 30⁰C-WBGT. There was a further significant increase in rate ratio for heat-related injury above 33 °C-WBGT. It was notable that the incident rates for both heat-related disorders and acute injuries increased at thermal conditions generally considered to be below the occupational exposure limit (OEL) at 30 ⁰C-WBGT. The rate of heat-related disorders increased substantially above the occupational exposure limit.

This dissertation focuses on an occupational stressor that has been recently introduced to the literature, illegitimate tasks, or tasks that seem unreasonable or unnecessary at work. Previous work has demonstrated the relationship between illegitimate tasks and a narrow set of discrete emotions as well as negative employee performance behaviors. The current research contributes to the literature by expanding the nomological network associated with illegitimate tasks and uses a rigorous daily diary methodology in a full-time working sample. It was expected that illegitimate tasks reduce state levels of self-esteem as well as other employee well-being indicators including anger, depressive mood, fatigue, job satisfaction, and sleep quality. Ninety participants filled out trait level surveys and subsequently completed daily dairy questionnaires three times daily for two workweeks. Daily diaries assessed experiences of illegitimate tasks as well as self-esteem and well-being. Hierarchical linear modeling was used to test primary hypotheses. Results indicate that anger and job satisfaction are consistently, significantly associated with illegitimate task episodes throughout workdays; however, responses dissipate overnight. Depressive mood and fatigue tend to be related to illegitimate tasks as the workday carries on and these responses appear to persist into the following workday. Results are consistent with the notion that illegitimate tasks reduce state self-esteem. However, high trait levels of self-esteem may negate this relationship. No effects on sleep quality were evident. In sum, daily experience of illegitimate task episodes represents a meaningful occupational stressor that predicts reductions in employee self-esteem and employee well-being.

Musculoskeletal injuries lead to most claims even though needlestick injuries receive the most attention. In 2010, health expenditures in the United States neared $2.6 trillion. CNAs, orderlies, and attendants had the highest rates of musculoskeletal disorders of all occupations with an incidence of 249 per 10,000 compared to 34 per 10,000 for all workers. The financial burden of back injuries in the healthcare industry is estimated to add up to $20 billion annually. Data was extracted for cause of injury, nature of injury and body part injured. Extracted data was analyzed both descriptively and by logistic and linear regression using SAS version 9.2. Results were significant for falls, lifting, being struck and pushing and pulling as major causes for injury. Regarding the nature of injury, sprains and strains constituted the majority of claims. The lower back was the body part most commonly injured in a claim. It was concluded that emphasis must be placed on risk factors for musculoskeletal injuries such as falls, lifting, temporal and environmental factors, age and lifestyle factors rather than needlestick injuries. Results from this study will be used to characterize risk factors for occupational injuries in CNAs and nurses, and to devise and implement preventive measures, including new legislation, to curb such injuries.

Personnel who work on the flight deck of an aircraft carrier are exposed to extreme levels of jet engine noise often in excess of 140 decibels (dB). The current circumaural hearing protective devices (CAHPD) employed by flight deck crewmen are inadequate for the level of protection required for these extreme levels of noise. Fiber-reinforced thermoset polymer composite (FRPC) materials such as aramid fibers used in body armor, have high theoretical values of acoustic impedance due to a fundamentally high modulus of elasticity and may offer a superior level of hearing protection over original equipment (OE) thermoplastic CAHPDs. The objective of this project was to measure and evaluate the attenuation of CAHPD’s constructed from FRPC materials. FRPC CAHPD ear cups were paired with OE thermoplastic CAHPD ear cups of equal shape and thickness, and the protected and unprotected A-weighted sound pressure level (SPL) was measured in continuous and impulse noise environments >80 dBA using a JOLENE manikin. These data were evaluated for paired differences between the protected and unprotected mean SPL, and OE protected and FRPC protected mean SPL and indicates that OE thermoplastic CAHPDs provide greater sound attenuation of continuous noise >80 dBA and aramid FRPC CAHPDs provide greater sound attenuation of impulse noise >80 dBA.

Latino immigrants encounter an entanglement of rights and policies after occupational injury or illness. In collaboration with an immigrant worker center, ethnographic research and a survey are used to analyze injured workers’ experiences. The center uses survey results to identify common threads and systematic problems, and to explore potential direct action. Through interviews with workers and medical and legal professionals, I investigate the barriers Latino immigrants face following occupational injury or illness, how their lived experiences relate to the greater medicolegal frameworks that demarcate most formal processes of compensation and treatment, and the experiences of professionals who mediate these structures. Research results confirm that immigrant workers lack information about their labor rights and the workers’ compensation system, which prevents them from filing claims, and contributes to the underreporting of workplace injuries. However, this research project also documents how workers who do file claims and report injuries are systematically barred access to redress due to a confluence of factors including unresponsive and fraudulent employers, biases in the medical system, discourses of deservingness, insufficient protections from retaliation, and the effects of a market-based medical system. I argue that future work-related injury prevention efforts should go beyond rights education, and include reforms to the compensation system.

Although the Ministry of Health, Indonesia, has achieved some successful occupational health interventions, published literature on such interventions in Indonesia remains scarce. This study utilized mixed methods of qualitative and quantitative research for the years 2010 and 2011. The qualitative study covered respondents in West, Central, and East Java Provinces to gather stakeholders' perspectives on the impact, effectiveness, adoption, implementation, maintenance, and barriers of occupational health services for informal sectors in Indonesia. The quantitative portion measured the impact of occupational health training for community health officers using Reach, Efficacy, Adoption, Implementation and Maintenance (RE-AIM) dimensions. West Java, as a province with a center for occupational health referral services (Balai Kesehatan Kerja Masyarakat/BKKM), was compared to Central Java as a province without BKKM. The qualitative study showed that interventions improved knowledge of and engagement in occupational health among workers and health officers. Among other improvements, occupational health training resulted in some owners of food processing home industries switching from non-food to food-based coloring. The advocacy program improved local governments' political commitment to funding the occupational health program. The BKKM played important roles in delivering occupational health in West Java Province. The quantitative study showed the efficacy variable to have the lowest p-value (p:<.0001). Meanwhile, the reach variable showed on the second lowest p-value among RE-AIM components (p: <.0190). Moreover, education (p-value: 0.0001), job type (p-value: 0.0015), and job duration (p-value: 0.0289) were considered individual variables that could have contributed to the differences in RE-AIM scores between Central and West Java. The qualitative study confirmed that occupational health interventions in Indonesia resulted in some positive impacts related to safe and healthy work-related behaviors. The quantitative study found that West Java, a province with BKKM, had a better RE-AIM score as compared to Central Java, a province without BKKM. Some individual variables such as education, job type, and job duration could have contributed to the differences in RE-AIM scores between Central and West Java. The future direction of the occupational health-training program should consider the participants' diversity in their education, job type, and job duration.