The relationship between surgical residents' perception of leadership and patient safety culture

Introduction. Patient safety culture is the integration of interrelated practices that once developed is supported by both the culture and leadership of the organization (Sagan, 1993). The purpose of this study is to describe and examine the relationship between surgical residents’ perception of their leadership and the resulting organizational safety culture within their clinical setting. This assessment is important to understanding the extent that leadership style affects the perception of the safety culture.^ Methods. A secondary dataset was used which included data from 68 surgical residents from two survey instruments, Organizational Description Questionnaire (ODQ) and Patient Safety Climate In Healthcare Organizations (PSCHO) Survey. Multiple regressions followed by hierarchical regressions with the introduction of the Post Graduate Year (PGY) variable examined the association between the leadership styles, Transactional and Transformational and the organizational safety culture variables, Overall Emphasis on Safety, Senior management engagement, Organizational resources for safety. Independent t-tests were conducted to assess whether males and females differ among the organizational safety culture variables and either leadership style.^ Results. The surgical residents perceived their organizational leadership to have greater emphasis placed on transformational leadership culture style relative to transactional leadership culture style. The only significant association found was between Transformational leadership and Organizational resources for safety. PGY had no significant effect on the leadership or the safety culture perceived. No significant difference was found between females and males in regards to the safety culture or the leadership style.^ Discussion. These results have implications as they support the premise for the study which is surgical residents perceive their existing leadership and organizational culture to be more transformational in nature than transactional. Significance was found between the leadership perceived and one of the safety culture variables, Organizational resources for safety. The foundation for this association lies in the fact that surgical residents are the personnel which are a part of the organizational resources. Although PGY differentiation did not seem to play a difference in the leadership perceived this could be attributed to the small sample size. No gender difference were found which supports the assumption that within such a highly specialized group such as surgical residents there is no gender differences since the highly specialized field draws a certain type of person with distinct characteristics. In future research these survey tools can be used to gauge the survey audiences’ perception and safety interventions can be developed based on the results. ^

Psychosocial factors and musculoskeletal symptoms in a vulnerable working population in Nicaragua

This research is a secondary data analysis of the CUPID-INCA Nicaragua study, a cross-sectional study comparing psychosocial and physical factors on musculoskeletal symptoms among nurses, office workers and maquiladoras in Nicaragua. There were three objectives for this thesis. (1) To describe the study population according to their socio-demographic, psychosocial (i.e. work organization and health beliefs) and physical factors. (2) To estimate the prevalence of musculoskeletal disorders (MSDs) in the study population (nurses, office workers and maquilas). (3) To analyze and compare the trends of association between psychosocial factors and MSDs to that of physical factors and MSDs in the study population. Trends of association between MSDs and psychosocial factors were also compared between nurses, office workers and maquilas. ^ Majority of the total study population were females, middle aged, non smokers and had been on the job for more than five years. Prevalence rates of low back pain and upper extremity pain were 28% and 37% respectively in nurses, 17% and 34% in office workers and 18% and 31% in maquilas. Workers' health belief was significantly associated with MSDs in all three occupational groups. Psychosocial factors were not consistently associated more with MSDs than physical factors. Maquilas had more psychosocial factors statistically significantly associated with musculoskeletal symptoms than nurses and office workers. ^ The findings of this research suggest that both psychosocial and physical risk factors play a role on the prevalence of musculoskeletal symptoms in the three working populations in Nicaragua. Future research in this area should explore further, the risk of developing MSDs from workers' exposure to psychosocial factors as well as physical factors.^

Cancer perceptions: Implications from the 2007 Health Information National Trends Survey

Background. Research has demonstrated associations between sociodemographic characteristics and illness perceptions; however, the impact of cancer exposure through personal or family diagnoses is not well-studied. The purposes of this study were to examine the prevalence of different cancer beliefs and the disparity in cancer beliefs across groups of individuals with distinct cancer histories; and to identify whether, when adjusted for sociodemographic characteristics, cancer history predicts a set of cancer beliefs.^ Methods. Using Leventhal’s Common Sense Model and data from the 2007 Health Information National Trends Survey (N=7172), we constructed multivariable logistic regressions to evaluate the effect of different stimuli, including cancer experience, on cancer perceptions (e.g., risk, worry, causation, outcome).^ Results. Findings indicate significant associations between cancer history and cancer perceptions. Individuals with family and personal cancer histories were more likely than individuals without any cancer history to worry about getting cancer (OR=3.55, P<0.01), agree they will develop cancer in the future (OR=8.81, P<0.01), and disagree that cancer is most often caused by a person’s behavior or lifestyle (OR=1.24, P=0.03). Additionally, results support education’s role in forming cancer perceptions. Individuals with high levels of education were more likely to endorse cancer prevention (OR=1.68, P<0.01) and higher 5-year survival rates (OR=1.41, P<0.01). ^ Conclusions. Results indicate cancer history affects cancer perceptions throughout the cancer continuum. Additionally, cancer history may influence coping behaviors and outcomes related to cancer.^ Impact. Cancer education and survivorship programs should assess important variables (e.g., cancer history) to more effectively tailor services and monitor evolving needs throughout cancer care.^

Occupation and glioma: The Harris County Brain Tumor Study, 2001--2010

The relationship between occupational exposures and glioma has not been adequately assessed due to the lack of studies in current scientific literature. To address this disparity, the Harris County Brain Tumor Study, an ongoing population-based case-control study, began in January 2001. Longest-held occupation for 382 cases and 629 controls were frequency matched on age (within 5 years), sex, and race and placed into 14 predetermined occupational categories. Adjusted odds ratios and 95% confidence intervals were calculated for each category using multiple logistic regression. Potential confounders assessed included sex, age, smoking status, education and income. For all subjects, significantly elevated adjusted odds ratios were found in health-related (aOR=1.66; 95%CI=1.03, 2.68), teaching (aOR=1.84; 95%CI=1.17, 2.88), and protective service (aOR=3.6; 95%CI=1.05, 12.31) occupational categories after controlling for sex and education. A significantly lowered odds ratio was seen in the writers, artists, and entertainers category (aOR=0.14; 95%CI=0.03, 0.58). In the stratified analyses, which controlled for education, males had a significantly elevated odds ratio for protective service workers (aOR=4.83; 95%CI=1.24, 18.83) while a significantly lower odds ratio was found in mechanics and machine operators (aOR=0.33; 95%CI=0.12,0.87). In females, we observed a significantly elevated odds ratio in teachers (aOR=1.99; 95%CI=1.20,3.31) and a significantly lower odds ratio in clerical workers (aOR=0.63; 95%CI=0.45,0.90). These analyses revealed several significant associations and allowed for separate analyses by gender, distinguishing this study from many glioma studies. Further analyses should provide a large enough sample size to stratify by gender as well as histological subtype.^

Assessment of occupational exposures to organic chemicals in a plastics manufacturing facility

The objective of this dissertation was to design and implement strategies for assessment of exposures to organic chemicals used in the production of a styrene-butadiene polymer at the Texas Plastics Company (TPC). Linear statistical retrospective exposure models, univariate and multivariate, were developed based on the validation of historical industrial hygiene monitoring data collected by industrial hygienists at TPC, and additional current industrial hygiene monitoring data collected for the purposes of this study. The current monitoring data served several purposes. First, it provided information on current exposure data, in the form of unbiased estimates of mean exposure to organic chemicals for each job title included. Second, it provided information on homogeneity of exposure within each job title, through the use of a carefully designed sampling scheme which addressed variability of exposure both between and within job titles. Third, it permitted the investigation of how well current exposure data can serve as an evaluation tool for retrospective exposure estimation. Finally, this dissertation investigated the simultaneous evaluation of exposure to several chemicals, as well as the use of values below detection limits in a multivariate linear statistical model of exposures. ^

The origin and development of hyperammonemia following exposure to hydrazine in rabbits

Hydrazine $\rm (N\sb2H\sb4),$ an important liquid propellant and derivative chemical for pharmaceuticals and pesticides, produces coma and convulsions sometimes resulting in death. Hyperammonia was found in rabbits exposed to 18 mg/Kg of hydrazine. Results of Part One of this study of rabbits emphasize the importance of acute ammonia toxicity during the first three hours following exposure to hydrazine. At no time during this post exposure period did a significant reduction of hydrazine to ammonia occur. Therefore, the elevated blood ammonia was apparently secondary to the effects of hydrazine on metabolic pathways. Further, the results support the theory of competitive inhibition of ammonia by hydrazine and emphasize the need to monitor plasma ammonia following toxic exposure to hydrazine.^ In Part Two, urea, ammonia, CO$\sb2,$ pH, glucose, sodium, potassium, chloride and creatinine were measured for up to 4 hours following injection of 18 mg/Kg of hydrazine in each of two groups of five rabbits. One group received normal saline and the other group received 5% dextrose and water/normal saline. Hyperammonemia, minimal metabolic acidosis and hyperglycemia without increased urea were found in the rabbits receiving normal saline intravenous infusion and hydrazine injection. Hence, hypoglycemia does not appear to play a role in the development of hyperammonemia. A significant difference in the elevated ammonia levels between the two groups receiving dextrose and water/normal saline and normal saline at 1 hour occurred. There was no significant difference in the elevated ammonia levels seen between the two groups receiving dextrose and water/normal saline and normal saline at 2.5 and 4 hours. Thus at 1 hour the group receiving dextrose was able to utilize excess glucose to detoxify ammonia, while at 2.5 and 4 hours there was no significant difference in the two groups' ability to detoxify ammonia.^ Findings support the theory that hydrazine inhibits the formation of urea resulting in hyperammonemia. Results suggest that hydrazine at 18 mg/Kg, a known hypoglycemic agent, causes serious hyperammonemia without increasing urea production during hyperglycemia. These experiments support a unified theory for the toxic mechanism of action of hydrazine, i.e., the intermediary metabolic effects of hydrazine are brought about by the formation of hydrazones which encumber ATP synthesis and vitamin B$\sb6$ enzymatic reactions. ^

A nested case-control study of radiation exposure and brain cancer incidence in the United States Air Force

A nested case-control study design was used to investigate the relationship between radiation exposure and brain cancer risk in the United States Air Force (USAF). The cohort consisted of approximately 880,000 men with at least 1 year of service between 1970 and 1989. Two hundred and thirty cases were identified from hospital discharge records with a diagnosis of primary malignant brain tumor (International Classification of Diseases, 9th revision, code 191). Four controls were exactly matched with each case on year of age and race using incidence density sampling. Potential career summary extremely low frequency (ELF) and microwave-radiofrequency (MWRF) radiation exposures were based upon the duration in each occupation and an intensity score assigned by an expert panel. Ionizing radiation (IR) exposures were obtained from personal dosimetry records.^ Relative to the unexposed, the overall age-race adjusted odds ratio (OR) for ELF exposure was 1.39, 95 percent confidence interval (CI) 1.03-1.88. A dose-response was not evident. The same was true for MWRF, although the OR = 1.59, with 95 percent CI 1.18-2.16. Excess risk was not found for IR exposure (OR = 0.66, 45 percent CI 0.26-1.72).^ Increasing socioeconomic status (SES), as identified by military pay grade, was associated with elevated brain tumor risk (officer vs. enlisted personnel age-race adjusted OR = 2.11, 95 percent CI 1.98-3.01, and senior officers vs. all others age-race adjusted OR = 3.30, 95 percent CI 2.0-5.46). SES proved to be an important confounder of the brain tumor risk associated with ELF and MWRF exposure. For ELF, the age-race-SES adjusted OR = 1.28, 95 percent CI 0.94-1.74, and for MWRF, the age-race-SES adjusted OR = 1.39, 95 percent CI 1.01-1.90.^ These results indicate that employment in Air Force occupations with potential electromagnetic field exposures is weakly, though not significantly, associated with increased risk for brain tumors. SES appeared to be the most consistent brain tumor risk factor in the USAF cohort. Other investigators have suggested that an association between brain tumor risk and SES may arise from differential access to medical care. However, in the USAF cohort health care is universally available. This study suggests that some factor other than access to medical care must underlie the association between SES and brain tumor risk. ^

Genetic susceptibility, cigarette smoking, and wood dust exposure in lung cancer: Case control analyses

This case control study was conducted to assess the association between lung cancer risk, mutagen sensitivity (a marker of cancer susceptibility), and a putative lung carcinogen, wood dust exposure. There were 165 cases (98 African-Americans, 67 Mexican-Americans) with newly diagnosed, previously untreated lung cancer, and 239 controls, frequency-matched on age, sex, and ethnicity.^ Mutagen sensitivity ($\ge$1 break/cell) was associated with a statistically significant elevated risk for lung cancer (odds ratio (OR) = 4.1, 95% confidence limits (CL) = 2.3,7.2). Wood dust exposure was also a significant predictor of risk (OR = 2.8, 95% CL = 1.2,6.6) after controlling for smoking and mutagen sensitivity. When stratified by ethnicity, wood dust exposure was a significant risk factor for African-Americans (OR = 4.0, 95% CL = 1.4,11.5), but not for Mexican-Americans (OR = 1.5, 95% CL = 0.3,7.1). Stratified analysis suggested a greater than multiplicative interaction between wood dust exposure and both mutagen sensitivity and smoking.^ The cases had significantly more breaks on chromosomes 4 and 5 than the controls did with ORs of 4.9 (95% CL = 2.0, 11.7) and 3.9 (95% CL = 1.6, 9.3), respectively. Breaks at 4p14, 4q27, 4q31, 5q21-22, 5q31, and 5q33 were significantly more common in lung cancer patients than in controls. Lung cancer risk had a dose-response relationship with breaks on chromosomes 4 and 5. Cigarette smoking had a strong interaction with breaks on chromosomes 2, 4, and 5.^ In a molecular cytogenetic study, using chromosome painting and G-banding, we showed that: (1) the proportion of chromosome 5 abnormalities surviving as chromosome-type aberrations remained significantly higher in cells of lung cancer cases (14%) than in controls (5%) (P $<$ 0.001). However, no significant differences were detected in chromosome 4 abnormalities between cases and controls; (2) the proportion of chromosome 5q13-22 abnormalities was 5.3% in the cases and 0.7% in the controls (P $<$ 0.001). 5q13-22 regions represented 40% of all abnormalities on chromosome 5 in the cases and only 14% in the controls.^ This study suggests that mutagen sensitivity, wood dust exposure, and cigarette smoking were independent risk factors for lung cancer, and the susceptibility of particular chromosome loci to mutagenic damage may be a genetic marker for specific types of lung cancer. ^

Occupational injuries among day laborers in Houston

Research has indicated that day laborers engage in higher risk occupations and suffer a high number of occupationally related fatal and non-fatal injuries. Although there have been some studies focusing on immigrant workers and their occupational injuries, none to our knowledge has studied Houston’s day laborers. An exploratory study of Houston’s day laborer population was conducted in 2008 by Dr. Fernández-Esquer from the University of Texas. ^ The aims of the current study are to analyze secondary data from this parent study and describe the prevalence of the self reported occupational injuries among Houston immigrant day laborers seeking work during the months of October through December 2008. The study also aims to determine if the reported injuries varied by age group, education level, length of time living in the U.S. and length of time working as day laborers and describe if injuries were more common by the number of different job types or job conditions reported or the use of personal protective equipment used (PPE). ^ This study analyzed 325 questionnaires that included job-related information from the parent study. One hundred and nine workers (35 %) reported an occupational injury or illness in the year before the interview. The most frequent injuries or illnesses reported were falls (26.7 %), cuts and lacerations (23.3 %) and being struck by an object (18.3 %). Over half of the workers (57 %) reported working 4 to 6 different jobs in the year before the interview, followed by 22.5 % reporting 1 to 3 different jobs. A combined 79 % of day laborers in Houston reported exposure to 7 or more of the job conditions listed and 69 % of those workers also reported an injury or illness. PPE use varied from 44 % of workers reporting using 4 to 6 PPE items to 6.8 % reporting not using any type of PPE. Thirty two percent of workers reporting not using any PPE also reported an injury or illness. ^ Injuries were found not to have varied significantly by age group, time living in the US, time working as a day laborer, numbers of different job types and the number of PPE used. Injuries did vary significantly by education level of the participants and the number of different job conditions reported (education, X2 (4, N = 315) = 12.651, p =0.013; and job conditions, X2 (3, N = 319) = 14.698, p = 0.002). ^ Although this first study of Houston’s day laborers was successful at engaging the population and getting background information regarding the occupational health of these workers, more studies are needed to further characterize the day laborers occupational experiences and injuries along with determining what specific job types and job conditions were present when injuries occurred and what kind of PPE was being used at the time. It is also clear that these workers need better safety training programs regarding working in potentially dangerous jobs and job conditions. They would also benefit from programs that would help empower them to negotiate for safer conditions.^

A multi-site pilot test study to measure safety climate in the university work setting

Next to leisure, sport, and household activities, the most common activity resulting in medically consulted injuries and poisonings in the United States is work, with an estimated 4 million workplace related episodes reported in 2008 (U.S. Department of Health and Human Services, 2009). To address the risks inherent to various occupations, risk management programs are typically put in place that include worker training, engineering controls, and personal protective equipment. Recent studies have shown that such interventions alone are insufficient to adequately manage workplace risks, and that the climate in which the workers and safety program exist (known as the "safety climate") is an equally important consideration. The organizational safety climate is so important that many studies have focused on developing means of measuring it in various work settings. While safety climate studies have been reported for several industrial settings, published studies on assessing safety climate in the university work setting are largely absent. Universities are particularly unique workplaces because of the potential exposure to a diversity of agents representing both acute and chronic risks. Universities are also unique because readily detectable health and safety outcomes are relatively rare. The ability to measure safety climate in a work setting with rarely observed systemic outcome measures could serve as a powerful means of measure for the evaluation of safety risk management programs. ^ The goal of this research study was the development of a survey tool to measure safety climate specifically in the university work setting. The use of a standardized tool also allows for comparisons among universities throughout the United States. A specific study objective was accomplished to quantitatively assess safety climate at five universities across the United States. At five universities, 971 participants completed an online questionnaire to measure the safety climate. The average safety climate score across the five universities was 3.92 on a scale of 1 to 5, with 5 indicating very high perceptions of safety at these universities. The two lowest overall dimensions of university safety climate were "acknowledgement of safety performance" and "department and supervisor's safety commitment". The results underscore how the perception of safety climate is significantly influenced at the local level. A second study objective regarding evaluating the reliability and validity of the safety climate questionnaire was accomplished. A third objective fulfilled was to provide executive summaries resulting from the questionnaire to the participating universities' health & safety professionals and collect feedback on usefulness, relevance and perceived accuracy. Overall, the professionals found the survey and results to be very useful, relevant and accurate. Finally, the safety climate questionnaire will be offered to other universities for benchmarking purposes at the annual meeting of a nationally recognized university health and safety organization. The ultimate goal of the project was accomplished and was the creation of a standardized tool that can be used for measuring safety climate in the university work setting and can facilitate meaningful comparisons amongst institutions.^

A comparative analysis of Texas and Louisiana Oil-field NORM Waste Policy

NORM (Naturally Occurring Radioactive Material) Waste Policies for the nation's oil and gas producing states have been in existence since the 1980's, when Louisiana was the first state to develop a NORM regulatory program in 1989. Since that time, expectations for NORM Waste Policies have evolved, as Health, Safety, Environment, and Social responsibility (HSE & SR) grows increasingly important to the public. Therefore, the oil and gas industry's safety and environmental performance record will face challenges in the future, about its best practices for managing the co-production of NORM wastes. ^ Within the United States, NORM is not federally regulated. The U.S. EPA claims it regulates NORM under CERCLA (superfund) and the Clean Water Act. Though, there are no universally applicable regulations for radium-based NORM waste. Therefore, individual states have taken responsibility for developing NORM regulatory programs, because of the potential radiological risk it can pose to man (bone and lung cancer) and his environment. This has led to inconsistencies in NORM Waste Policies as well as a NORM management gap in both state and federal regulatory structures. ^ Fourteen different NORM regulations and guidelines were compared between Louisiana and Texas, the nation's top two petroleum producing states. Louisiana is the country's top crude oil producer when production from its Federal offshore waters are included, and fourth in crude oil production, behind Texas, Alaska, and California when Federal offshore areas are excluded. Louisiana produces more petroleum products than any state but Texas. For these reasons, a comparative analysis between Louisiana and Texas was undertaken to identify differences in their NORM regulations and guidelines for managing, handling and disposing NORM wastes. Moreover, this analysis was undertaken because Texas is the most explored and drilled worldwide and yet appears to lag behind its neighboring state in terms of its NORM Waste Policy and developing an industry standard for handling, managing and disposing NORM. As a result of this analysis, fourteen recommendations were identified.^

An assessment of the relative influence of a vapor recovery system in reducing occupational exposure to volatile organic compounds in high performance liquid chromatography

Occupational exposures to organic solvents, specifically acetonitrile and methanol, have the potential to cause serious long-term health effects. In the laboratory, these solvents are used extensively in protocols involving the use of high performance liquid chromatography (HPLC). Operators of HPLC equipment may be potentially exposed to these organic solvents when local exhaust ventilation is not employed properly or is not available, which can be the case in many settings. The objective of this research was to characterize the various sites of vapor release in the HPLC process and then to determine the relative influence of a novel vapor recovery system on the overall exposure to laboratory personnel. The effectiveness of steps to reduce environmental solvent vapor concentrations was assessed by measuring exposure levels of acetonitrile and methanol before and after installation of the vapor recovery system. With respect to acetonitrile, the concentration was not statistically significant with p=0.938; moreover, exposure after the intervention was actually higher than prior to intervention. With respect to methanol, the concentration was not statistically significant with p=0.278. This indicates that the exposure to methanol after the intervention was not statistically significantly higher or lower than prior to intervention. Thus, installation of the vapor recovery device did not result in statistically significant reduction in exposures in the settings encountered, and acetonitrile actually increased significantly.^

Pilot study assessment of indoor air quality in two dental settings: Particulate matter and volatile organic compounds

Objective: To assess the indoor environment of two different types of dental practices regarding VOCs, PM2.5, and ultrafine particulate concentrations and examine the relationship between specific dental activities and contaminant levels. Method: The indoor environments of two selected dental settings (private practice and community health center) will were assessed in regards to VOCs, PM 2.5, and ultrafine particulate concentrations, as well as other indoor air quality parameters (CO2, CO, temperature, and relative humidity). The sampling duration was four working days for each dental practice. Continuous monitoring and integrated sampling methods were used and number of occupants, frequency, type, and duration of dental procedures or activities recorded. Measurements were compared to indoor air quality standards and guidelines. Results: The private practice had higher CO2, CO, and most VOC concentrations than the community health center, but the community health center had higher PM2.5 and ultrafine PM concentrations. Concentrations of p-dichlorobenzene and PM2.5 exceeded some guidelines. Outdoor concentrations greatly influenced the indoor concentration. There were no significant differences in contaminant levels between the operatory and general area. Indoor concentrations during the working period were not always consistently higher than during the nonworking period. Peaks in particulate matter concentration occurred during root canal and composite procedures.^

A comparison of worker risk of injury while working on fully automated side loaders and other residential collection trucks at a large solid waste collection company

The study aim was to determine whether using automated side loader (ASL) trucks in higher proportions compared to other types of trucks for residential waste collection results in lower injury rates (from all causes). The primary hypothesis was that the risk of injury to workers was lower for those who work with ASL trucks than for workers who work with other types of trucks used in residential waste collection. To test this hypothesis, data were collected from one of the nation’s largest companies in the solid waste management industry. Different local operating units (i.e. facilities) in the company used different types of trucks to varying degrees, which created a special opportunity to examine refuse collection injuries and illnesses and the risk reduction potential of ASL trucks.^ The study design was ecological and analyzed end-of-year data provided by the company for calendar year 2007. During 2007, there were a total of 345 facilities which provided residential services. Each facility represented one observation.^ The dependent variable – injury and illness rate, was defined as a facility’s total case incidence rate (TCIR) recorded in accordance with federal OSHA requirements for the year 2007. The TCIR is the rate of total recordable injury and illness cases per 100 full-time workers. The independent variable, percent of ASL trucks, was calculated by dividing the number of ASL trucks by the total number of residential trucks at each facility.^ Multiple linear regression models were estimated for the impact of the percent of ASL trucks on TCIR per facility. Adjusted analyses included three covariates: median number of hours worked per week for residential workers; median number of months of work experience for residential workers; and median age of residential workers. All analyses were performed with the statistical software, Stata IC (version 11.0).^ The analyses included three approaches to classifying exposure, percent of ASL trucks. The first approach included two levels of exposure: (1) 0% and (2) >0 - <100%. The second approach included three levels of exposure: (1) 0%, (2) ≥ 1 - < 100%, and (3) 100%. The third approach included six levels of exposure to improve detection of a dose-response relationship: (1) 0%, (2) 1 to <25%, (3) 25 to <50%, (4) 50 to <75%, (5) 75 to <100%, and (6) 100%. None of the relationships between injury and illness rate and percent ASL trucks exposure levels was statistically significant (i.e., p<0.05), even after adjustment for all three covariates.^ In summary, the present study shows that there is some risk reduction impact of ASL trucks but not statistically significant. The covariates demonstrated a varied yet more modest impact on the injury and illness rate but again, none of the relationships between injury and illness rate and the covariates were statistically significant (i.e., p<0.05). However, as an ecological study, the present study also has the limitations inherent in such designs and warrants replication in an individual level cohort design. Any stronger conclusions are not suggested.^

Change in permeation rates of acids and bases through limited use protective fabrics after repeated wash cycles

The primary objective of this study was to determine if there is a change in permeation rates when limited use protective fabrics undergo repeated exposure and wash cycles. The null hypothesis of this study was that no substantial change in permeation takes place after the test material is subjected to repeated contact with a strong acid or base and has undergone repeated wash cycles. ^ The materials tested were DuPont Tychem® CPF 3 and CPF 4 fabrics. The challenge chemicals in this study were ninety-eight percent sulfuric acid and fifty percent sodium hydroxide. Permeation testing was conducted utilizing ASTM designation F739-99a Standard Test Method for Resistance of Protective Clothing Materials to Permeation by Liquids or Gases Under Conditions of Continuous Contact. ^ In this study, no change in permeation rates of either challenge chemical was detected for CPF 3 or CPF 4 limited use protective fabrics after repeated exposure and wash cycles. Certain unexposed areas of the fabric suffered structural degradation unrelated to exposure and which may be due to multiple washings.^