Dissertations / Theses on the topic 'Public health|Occupational safety'

Heat stress is a recognized occupational hazard present in many work environments. Its effects increase with increasing environmental heat loads. There is good evidence that exertional heat illness is associated with ambient thermal conditions in outdoor environments. Further, there is reason to believe that risk of acute injury may also increase with the ambient environment. For these reasons, the assessment of heat stress, which can be done through the characterization of the wet bulb globe temperature (WBGT), is designed to limit exposures to those that could be sustained for an 8-h day. The ACGIH Threshold Limit Value (TLV) for heat stress was based on limited data from Lind in the 1960s. Because there are practical limitations of using thermal indices, measurement of physiological parameters, such as body temperature and heart rate are used with environmental indices or as their alternative.

The illness and injury records from the Deepwater Horizon cleanup effort provided an opportunity to examine the effects of ambient thermal conditions on exertional heat illness and acute injury, and also the cumulative effect of the previous day’s environmental conditions. The ability of the current WBGT-based occupational exposure limits to discriminate unsustainable heat exposures, and the proposal of alternative occupational limits was performed on data from two progressive heat stress protocol trials performed at USF. The USF studies also provided the opportunity to explore physiological strain indicators (rectal temperature, heart rate, skin temperature and the Physiological Strain Index) to determine the threshold between unsustainable and sustainable heat exposures. Analysis were performed using Poisson models, conditional logistic regressions, logistic regressions, and receiver operator curves (ROC curves).

It was found that the odds to present an acute event, either exertional heat illness or acute injuries increased significantly with rising environmental conditions above 20 °C (RR 1.40 and RR 1.06, respectively). There was evidence of the cumulative effect from the prior day’s temperature and increased risk of exertional heat illness (RRs from 1.0–10.4). Regarding the accuracy of the current TLV, the results of the present investigation showed that this occupational exposure limit is extremely sensitive to predict cases associated with unsustainable heat exposures, its area under the curve (AUC) was 0.85; however its specificity was very low (specificity=0.05), with a huge percentage of false positives (95%). The suggested alternative models improved the specificity of the occupational exposure limits (specificities from 0.36 to 0.50), maintaining large AUCs (between 0.84 and 0.89). Nevertheless, any decision in trading sensitivity for specificity must be taken with extreme caution because of the steeped increment risk of heat related illness associated with small increments in environmental heat found also in the present study. Physiologic heat strain indices were found as accurate predictors for unsustainable heat stress exposures (AUCs from 0.74 to 0.89), especially when measurements of heart rate and skin temperature are combined (AUC=0.89 with a specificity of 0.56 at a sensitivity=0.95). Their implementation in industrial settings seems to be practical to prevent unsustainable heat stress conditions.

A variety of paint products are used for their aesthetic and anti-corrosive properties. Isocyanates are consistently found in automobile paint products, particularly in clear coat polyurethane products. Clear coat is typically sprayed via pressurized air by means of an auto-spray robot. In clear coat repair situations, manual, air-powered spray guns are used, and manual spray Operators administer the clear coat material. The isocyanates are a primary anti-corrosive agent in polyurethane products. The Occupational Safety and Health Administration (OSHA) has not established a Permissible Exposure Limit (PEL). The National Institute for Occupational Safety and Health (NIOSH) and American Conference of Governmental Industrial Hygienists (ACGIH) have set Recommended Exposure Limit (REL) and Threshold Limit Value (TLV), respectively. NIOSH recommends a 0.005 parts per million (ppm), 10-hour Time Weighted Average (TWA), and a ceiling exposure of 0.020 ppm in a 10 minute period. Similarly, ACGIH recommends a 0.005 ppm, 8 hour TWA.

Automobile manufacturers use clear coats in a variety of ways. Some may use clear coats with blocked isocyanates, or isocyanates that are completely reacted, and others may use clear coat products that allow isocyanates to be liberated during an application, baking, and curing process. The research objective of this study was to characterize exposure, focusing on a single manufacturer’s use of isocyanate-containing clear coats in their Paint Department. A newly evaluated medium (ISO 17734) using di-n-butylamine as a derivative agent, in a denuder tube, was selected instead of NIOSH methods 5521, 5522, and 5525. The ISO evaluated medium was selected to reduce secondary hazard exposure to toluene in impingers. Second, a medium developed by SKC, Inc., called ISO-CHEK®, was not selected because of the short collection time, sensitivity of the medium after collection, and storage and shipping requirements for analysis.

Sampling took place over two days, one day for manual spray operations with 2 personal samples from Operators, and 4 area samples collected, and the second day for auto-sprayer Inspectors with 4 personal samples collected. The samples were then analyzed for hexamethylene diisocyanates (HDI) monomer and homopolymer species. The 0.005 ppm, 10 hour TWA; the 0.020 ppm ceiling limit (10 minutes); and the 0.005 ppm 8-hour TWA TLV were not exceeded on either day of sampling. Neither the area nor the personal samples exceeded the 10 hour TWA, ceiling limit, or TLV. In fact, the results had to be recalculated in to parts per billion (ppb). The average exposure for manual spray Operators was 0.052 ppb for the homopolymer, and 0.024 ppb for the monomer species. For auto-spray Inspectors, the average was 0.053 ppb for the homopolymer component and 0.021 ppb for the monomer species. Though the average isocyanate concentration was similar for both Operators and Inspectors, the averages are still below REL and TLV recommendations. These data provided preliminary information regarding the exposure to isocyanates from clear coat use, and also provide context for future evaluation of isocyanate use at this automobile manufacturer. The low concentration of isocyanates could indicate working ventilation systems, liberation of isocyanate species to non-hazardous forms, or low volatilization of isocyanates from the clear coat.

The purpose of this case study was to explore the perceptions and experiences of hospital emergency preparedness coordinators of preparing for and responding to incidents. Stakeholder and protection motivation theories provided the theoretical framework for the study. The nonprobability sampling technique of purposive sample was used to identify 10 hospital preparedness coordinators employed at acute care hospitals with emergency departments located in Connecticut and Massachusetts. A field-tested researcher developed 20-question interview questionnaire guided data collection. This qualitative case study answers the questions: What are hospital emergency preparedness coordinators perspectives of hospital preparedness? How do hospital emergency preparedness coordinators prepare for a hospital incident? How do hospital emergency preparedness coordinators respond to a hospital incident? What factors do hospital emergency preparedness coordinators believe best prepares a hospital for incidents? Ranked in order of replication, the researcher identified three themes using first and second cycle coding techniques with pattern coding: (a) planning, (b) training, and (c) communication. Control and motivation emerged as subthemes. Results of the study provide detail rich data for hospital emergency preparedness coordinators, and provide insight and information for stakeholders from all types of private and public organizations to improve hospital emergency preparedness programs.

Objectives: The purpose of this secondary data analysis was to examine "stage of change" as a predictor of attrition among participants in a worksite wellness program. A Conceptual Model of Attrition was developed to examine health screening, health risk appraisal (HRA), and demographic predictors of attrition as well. Methods: Data for this study were drawn from a worksite wellness program which was sponsored by an integrated rural healthcare system. The sample consisted of 1058 individuals for whom valid demographic, health screening, and HRA data were available. Of the total sample, 414 did not participate in a subsequent year (39.1% attrition). This research was conducted as a predictive correlational study using binary logistic regression analysis. Results: Significant associations between stage of change and attrition were found for the physical activity, nutrition, weight, stress, and overall healthy lifestyle health behavior areas. The stage of change with the highest odds of attrition was the preparation stage across these health behavior areas. In the Conceptual Model of Attrition, significant associations with attrition were found for emotional symptoms, emotional health limitations, health view, and overall healthy lifestyle stage of change. Conclusions: This research has shown that the stage of change construct is useful for predicting attrition. Identification of participants' stage of change offers a leverage point for engagement in worksite wellness programs and for prevention of program attrition. For employers, retention of these employees in their worksite wellness program could yield a greater return on investment resulting in lower health care costs, fewer missed work days, and higher productivity on the job.

Firefighters and asphalt pavers are exposed to polycyclic aromatic hydrocarbons (PAHs) during various work activities. The purpose of this study was to evaluate urinary PAH levels and compare these bio-monitoring levels among firefighters, asphalt pavers, and non-occupationally exposed individuals. The National Institute of Standards and Technology (NIST) urinary PAH levels were used for non-occupationally exposed controls. When compared to the NIST standard for smokers and non-smokers, firefighters demonstrated statistically significant differences in urinary concentration differences for the following metabolites: 2-OH-fluorene, 3-OH-fluorene and 1-OH-pyrene, which were lower in firefighters than the NIST mean for smokers. 1-OHphenanthrene, 2-OH-phenanthrene and 3-OH-phenanthrene were higher among world trade center exposed firefighters than the NIST mean for smokers. When firefighters were compared to the NIST non-smoker standard, firefighters demonstrated elevated levels in all tested PAH biomarkers due to a mixture of smokers and non-smokers in the firefighter cohort.

Asphalt workers had statistically significant higher urinary concentration elevations in 2OH-fluorene, 1-OH-phenanthrene and 3-OH-phenanthrene as compared to the NIST smoker mean. When asphalt pavers were compared to the NIST non-smoker mean, asphalt pavers had statistically significant increases in all tested PAH biomarkers, with the exception of 2-OHphenanthrene. While firefighters did not demonstrate a substantial change in urinary PAH metabolite levels compared to control populations of smokers and non-smokers, asphalt pavers experienced concentrations that were in some cases increased by orders of magnitude compare to NIST controls. Future research may be needed to evaluate any potential health risk posted to occupational exposed asphalt pavers.

The Occupational Health and Safety Administration (OSHA) estimates that half a million surgical staff are exposed to laser smoke or plume each year. It has been suggested that the type and intensity of exposure is dependent in part on the way a laser is used during surgery. The purpose of this study was to estimate emission rates of the gas phase constituents of laser generated air contaminants using a validated emission chamber methodology while differentiating the effects of the laser operational parameters power, pulse-repetition frequency, and beam diameter, and ultimately to model a set of plausible occupational exposures.

An emission chamber was designed, fabricated, and validated to quantify the emission rates of gases and particles associated with laser generated air contaminants (LGACs) during a simulated surgical procedure. The emission chamber was built of inert materials, including a glass hood section connected to a duct section for collection and allowing for lasing of tissue. The performance, plume capture, and air flow of the emission chamber system were validated. This validated emission chamber and methodology enabled accurate estimation of emission rates with low experimental variability that can be used in mathematical modeling of exposure.

Two medical lasers (Holmium Yttrium Aluminum Garnet [Ho:YAG] and carbon dioxide [CO₂]) were set at varying operational parameters in a simulated laser surgery on porcine skin to generate a plume in an emission chamber. Porcine skin was pyrolyzed with a medical laser set to a range of surgically plausible operational parameters. Consistency in the rate and depth of incision was established by a system to control the speed of laser movement and aim angle of the laser tip, and was validated by measurement of tissue loss. The plume was sampled for seven gas phase contaminants of combustion products (volatile organic compounds [VOC], formaldehyde, hydrogen cyanide [HCN], carbon dioxide (CO₂), carbon monoxide [CO]). The effect of each operational parameter was determined using a fractional factorial design coupled with a sequential screening process that evaluated the parameters for their influence on emission rates.

Measured concentrations of the gas phase contaminants were below the limit of detection (LOD). Confined to the experimental conditions of this investigation, results indicated that beam diameter was significantly influential to emission rates when using the Ho:YAG laser but not with the CO₂ laser. Power and pulse repetition frequency were not influential to emission rates of these gas phase contaminants.

Emission rates of LGAC from the experimentally determined concentrations were used to estimate a range of physically plausible occupational exposures to surgical staff. A two-zone semi-empirical model was implemented with input variables varied over a range based on the general requirements of a laser surgical suite in compliance with regulatory agencies. Twenty-minute time weighted averages were developed for the near- and far-field zones within the surgical suite as estimates of the occupational exposure to LGAC. These values were compared to relevant occupational exposure limits; estimated exposures were at least three times in magnitude less than the exposure limits and thus do not appear to present an occupational hazard.

This quantitative survey study explored relationships between a law enforcement supervisor's personal characteristics and the attitude a supervisor had towards the Critical Incident Stress Management (CISM) program. The study solicited law enforcement supervisors (n = 6635) who were graduates of the Federal Bureau of Investigation's National Academy (FBINA). A modified survey instrument assisted in the collection of demographic data and the assessment of attitudes towards the CISM program. Descriptive statistics and inferential statistics in the form of an analysis of variance (ANOVA) statistical test and a multiple regression analysis that used a backwards-stepwise format assisted in the examination of the collected data. The results indicated time away from the duties of a line-level patrol officer, investigator, or detective, and time in law enforcement shared a weak relationship with a supervisor's attitude towards the CISM program. More specifically, the longer the time span for each, the more positive the supervisor's attitude should be towards the program. Unfortunately, while these variables may have been deemed significant, the results are virtually meaningless since the model resulted in only two percent of the variance in attitude. Although the study's findings only indicated a weak link between a law enforcement supervisor's characteristics and the attitude a supervisor has towards the CISM program, it also showed supervisors within the study overwhelmingly supported the program. Knowing this support exists could still provide stress management program managers with invaluable insight, as processes are developed to mitigate critical incident stress in law enforcement.

U.S. Army Regulations require soldiers to be fit, as excessive weight negatively impacts their readiness, health, and morale. A quantitative study examined if personal, behavioral, and/or environmental factors predict a soldier’s self-efficacy and body mass index. Data were obtained from 117 soldiers on 6 scales: the Armed Services Vocational Aptitude Battery, the Army Physical Fitness Test, the General Self-Efficacy Scale, the Stress Management Questionnaire, the Lifestyle Assessment Inventory, and the Multifactor Leadership Questionnaire. Multiple regression analysis was used to determine if personal (intellectual capabilities and physical fitness), behavioral (lifestyle and stress management), and/or environmental (supervisor leadership) factors predict self-efficacy and body mass index in a convenience sample of battalion personnel. The analysis showed that lifestyle and stress management behavioral factors predict self-efficacy, whereas physical fitness predicts body mass index. In addition, there were significant correlations between self-efficacy, personal factors, and behavioral factors; between personal factors, behavioral factors, and body mass index; and between behavioral and environmental factors. Positive social change implications include the U.S. Army using these findings to promote healthy lifestyles, reduce stress, and increase physical fitness among soldiers to achieve higher self-efficacy and a lower body mass index. These findings also suggest that the military services would see better physical readiness by considering personal, behavioral, and environmental factors to meet standards.