IH General Practice I

IH General Practice I

Tuesday, June 2, 2015, 1:30 PM - 5:30 PM

SR-118-01 A Simulation Algorithm for Converting Historical Particle Count Data to Respirable Dust Mass

R. Rando, Tulane University SPH&TM, New Orleans, LA

Objective: Historically, inhalation exposures in dusty industries were measured with impinger collection/microscopic analysis to quantitate particle count concentration. In order to use such historical data for retrospective exposure assessment of ​​​industrial sand workers, a simulation algorithm to convert particle count data into modern measures of respirable dust mass was developed.

Methods: The simulation entails using an archival dust size distribution along with simulation software to randomly generate 100,000 virtual dust particles of varying diameters taken from a log-normal distribution having the same CMD and GSD as the archival sample. For each virtual particle, the equivalent respirable mass and particle count, based on its diameter, density, and its measurement efficiencies, were calculated. The mass and counts of the virtual particles were then totaled and ratioed to derive the conversion factor. Respirable dust measurement efficiency was calculated from a cumulative lognormal function with median aerodynamic diameter of 3.5 μm and GSD of 1.5 and truncated for particles > 10 µm. Impinger/microscopy measurement efficiency was set to zero for particles < 0.75 μm or > 5 μm based on microscopic limit of resolution and historical counting rules, whereas for particles between 0.75 and 5 µm, measurement efficiency was calculated from published impinger collection efficiencies for silica. The algorithm was evaluated in comparison to published experimental data from side-by-side sampling/analysis for respirable dust, particle counts, and size distributions for 5 types of mineral dust, and then applied to archival particle size data for industrial sand processing.

Results: The mean ratio of conversion factors determined from the algorithm and from direct sampling for the various mineral dusts was 1.09 (SD = 0.40) and there was no statistical difference (paired t-test; p = 0.79). For 14 archival samples from industrial sand plants, conversion factors ranged from 97–263 μg/m3 per mppcf and there was no statistical difference across process areas (drying, screening, vibrating, binning, bulk loading, bagging), ANOVA: p = 0.31. The overall mean conversion factor was 157 (SD = 42).

Conclusions: The simulation algorithm performed favorably in comparison to directly determined conversion factors. When applied to archival industrial sand data, the results were similar to that previously reported for siliceous dusts in granite sheds (~100 μg/m3 per mppcf).

CS-118-02 Comparison of Quantitative Exposure Assessment Results for Crystalline Silica (Respirable Fraction) with Current and Proposed Occupational Safety and Health Administration (OSHA) Standards

G. Desai, International Safety Systems, Inc., Houston, TX

Situation/Problem: OSHA’s current permissible exposure limits (PELs) for crystalline silica (respirable fraction) were adopted in 1971. Studies show that they do not adequately protect worker health. In the proposed OSHA limit, workers’ exposures would be limited to a new PEL of 50 micrograms of crystalline silica (respirable fraction) per cubic meter of air (μg/m3), averaged over an 8-hour day. Exposure to airborne silica dust was monitored in operations involving casting cleaning, shakeout and molding in a foundry.

Resolution: Full shift (eight-hour/ ten-hour) Time Weighted Average (TWA) personal breathing zone employee exposure monitoring for respirable crystalline silica was carried out using modified National Institute of Occupation Safety and Health (NIOSH) 7500/ OSHA ID-42 method. The results were compared with the current and proposed OSHA standards.

Results: Two of the four TWA results to Crystalline silica (respirable fraction) during casting cleaning operations exceeded the current calculated OSHA PEL. All four TWA results exceeded the proposed OSHA limit of 0.050 mg/m3. The three TWA results to crystalline silica (respirable fraction) during the shakeout operation were less than the current calculated OSHA PEL. Two of three TWA results for the shakeout operation exceeded the proposed OSHA limit of 0.050 mg/m3. One of the five TWA results to crystalline silica (respirable fraction) during molding operations exceeded the current calculated OSHA PEL. Three of the five TWA results for crystalline silica (respirable fraction) exceeded 50% of the proposed OSHA limit.

Lessons Learned: Most companies follow ACGIH TLV for comparing the crystalline silica (respirable fraction) results. These results support OSHA’s estimates that the proposed rule will save lives and prevent new cases of silicosis once the full effects of the rule are realized.

SR-118-03 Potential Exposure to Naturally Occurring Diacetyl, 2,3-Pentanedione and Respirable Dust from Roasting and Grinding Coffee Beans in an Industrial Setting

S. Gaffney,A. Abelmann, J. Pierce, M. Glynn, L. McCarthy, J. Lotter, M. Liong, J. Henshaw, B. Finley, Cardno ChemRisk, San Francisco, CA

Objective: Concerns have been raised about potential health effects associated with occupational exposure to diacetyl (DA), and more recently, its substitute, 2,3-pentanedione (2,3-P) in food and flavorings manufacturing workers. Both DA and 2,3-P are also natural components of various foods and beverages, including roasted coffee. We sought to characterize exposures to naturally occurring DA, 2,3-P and respirable dust (RD) at a facility that roasts and grinds coffee beans with no added flavoring agents.

Methods: A total of 59 stationary breathing zone samples were collected over the course of 3 roasting and grinding batches (lightly roasted soft beans, lightly roasted hard beans and dark roasted hard beans) in a facility with one roaster and grinder at varying distances from the roaster and grinder, respectively.

Results: Grinding and roasting processes lasted 8–11 and 37-41 min, respectively. DA, 2,3-P, and RD concentrations ranged from undetectable (ND) to 3.9 ppb, ND-18 ppb, and ND- 0.31 mg/m3 during roasting and 18–390 ppb, 8.9–210 ppb, and ND-1.7 mg/m3 during grinding operations, respectively. For any given bean/roast combination and sample location, DA and 2,3-P concentrations during grinding were higher than those measured during roasting and decreased with increased distance from the source. We found that DA and 2,3-P concentrations were significantly higher at the location nearest the emission source during grinding of the soft beans than during grinding of hard beans regardless of roast type. Overall, concentrations of respirable dust were well below occupational exposure limits (OELs), but all mean DA and 2,3-P concentrations measured closest to the grinder during grinding exceeded each of the current and proposed short-term OELs.

Conclusions: These results indicate that coffee-processing workers are potentially exposed to naturally occurring DA and 2,3-P in excess of the current and proposed OELs for these compounds. Based upon our review of the literature, coffee workers are not known to experience the chronic respiratory health effects that have been associated with exposures to diketones. Therefore, our findings raise questions about these suggested associations, as well as the appropriateness of the current and proposed corresponding OELs. Further research into these topics is, therefore, warranted.

SR-118-04 Systematic Review and Evaluation of Health Risks Associated with Sepiolite Exposure

M. Le, A. Monnot, M. Grespin, R. Ward, Cardno ChemRisk, San Francisco, CA

Objective: Sepiolite is a phyllosilicate and a member of the palygorskite-sepiolite group of clay minerals. Due to its physical and chemical properties it has been used in absorbents and environmental deodorants, asphalt coatings, agricultural applications, cosmetics, cigarette filters, and in drilling fluids. Based on its refractive index, fibrous sepiolite can be misidentified as chrysotile asbestos using some standard analytical techniques. Unlike chrysotile asbestos, the human health risk associated with exposure to fibrous sepiolite may not be well understood. Given sepiolite’s worldwide commercial and industrial use, this systematic literature review sought to evaluate the potential health risks associated with sepiolite exposure.

Methods: A systematic review, following PRISMA guidelines, of literature identified from PubMed, Embase, and Scopus was conducted with “sepiolite” and each of the following search terms: “health”, “cancer”, “exposure”, “health hazard”, and “toxicity”. Industry white papers, MSDSs, and government reports were also considered. Specific eligibility criteria were applied to all relevant documents identified.

Results: In total 471 documents were identified, with 18 included in this analysis. Human, animal, and in vitro studies assessing the exposure, toxicity, or health risk of sepiolite were identified. No specific health outcomes were identified from these studies; however, the results suggest that sepiolite’s potential relative toxicity is dependent upon grade and fiber size.

Conclusions: There is no indication that sepiolite is overtly hazardous and no conclusions regarding specific health endpoints can be taken from available studies as a whole. However, the toxicological literature suggests that its potency is dependent upon fiber grade and fiber size. Given the increasing use of sepiolite worldwide, as well as the potential for misidentification of sepiolite as other fibrous minerals, it is important that future studies are conducted to assess the exposures generated from occupational work with this mineral, as well as associated human health risks.

CS-118-05 Industrial Hygiene Exposure Monitoring Programs and Mine Sites: Gap Analysis

L. Clements, P. Bergholz, C. Doyle, AMEC, Burnaby, BC, Canada

Situation/Problem: Workers at mines sites are potentially exposed to a wide variety of health hazards. Exposures levels often exceed exposure standards requiring the implementation of exposure mitigation measures. A comprehensive industrial hygiene exposure monitoring program is essential to ensuring that the hazards to which workers are exposed are properly identified and assessed both qualitatively and quantitatively to determine where exposure issues exist, and determine appropriate short and long term mitigation measures. A comprehensive monitoring program is also necessary to meet occupational health and safety (OHS) regulatory requirements. Occupational exposure monitoring programs at mine sites vary in terms of their comprehensiveness and opportunities for improvement exist to meet both regulatory requirements as well as best practice.

Resolution: This presentation will review the typical chemical and physical hazards present at above ground and underground metal mines, highlight some of the exposure levels to which mine workers are exposed based on the presenter’s experience with the industry as a consultant and a review of recent literature on the subject, and overview the current state of some industrial hygiene programs at metal mine sites.

Results: The objective of this presentation is to identify some of the gaps that have been identified in some mine site industrial hygiene exposure monitoring programs and to discuss where opportunities for improvement exist.

Lessons Learned: One cannot expect operations staff / environmental / safety personnel who don’t have a strong background in IH to develop and implement an OHS Program without support. OHS Programs require careful thought, senior management commitment, and ongoing support to be successful. All stakeholders in the process have to be educated about industrial hygiene to be able to understand the objectives / goals of the program, and what is involved and necessary to make the program a success.

CS-118-06 Enhanced Confined Space Monitoring

W. Jones, Total Safety U.S., Inc., Chino Hills, CA

Situation/Problem: Addressed is the potential complexity of monitoring multiple confined space environments in refinery turnarounds. Precautionary measures must be well designed and understood by work crews. Real-time observations and data interpretation of multiple operations can be hard to keep up with for supervision and on site observers. Where an operation simultaneously has multiple confined space entries, coordination and oversight requirements are complex.

Resolution: A centralized monitoring location was developed, utilizing an integrated system that includes simultaneous data inputs from wireless closed circuit television cameras, badge/identification readers, wireless fixed gas monitoring instruments, audible and visual alarms and push-to-talk communications. The central location is staffed by technicians, trained in industrial hygiene gas detection, who can interpret monitor readings in multiple locations at once, improving risk assessment and communications with observers, entrants, supervisors and operations management during complicated and high hazard operations. These trained technicians, monitoring and interpreting simultaneously potentially hazardous situations enhance what on-site observers or “hole watches” see by providing immediate feedback from the centralized monitoring location.

Results: Use of this integrated approach on multiple refinery turnarounds has provided better real-time data interpretation and immediate observations of confined space entrants working in potentially high hazard environments. The central location for observations during multiple confined space entries has resulted in better coordination and better data interpretation. In other high hazard operations, this integrated system has provided more immediate feedback to plant operators in the process of clearing and breaking lines containing a chemical fluid. As an example, in a recent refinery turnaround where work crews were getting a Permit to Work in a Coker unit, continuous monitors located in the area allowed the plant operator to issue work permits in one fourth the time normally required.

Lessons Learned: From our experience, an integrated approach to multiple confined space entries simplifies communications and data flow to participants, enhances observations and improves risk control during this high hazard and historically deadly work.

CS-118-07 Mining in Northern Ontario, Canada: Challenges Facing Safety and Health

R. Korczynski, AMEC, Thunder Bay, ON, Canada


SR-118-08 Assessing the Health Effects of Rotating Shift Work among Refinery Workers

K. McNamara, UCLA, Santa Monica, CA; W. Robbins, UCLA, Santa Monica, CA

Objective: Refinery workers in operator and maintenance positions typically work extended, rotating shifts. This study aimed to characterize work schedules and prevalence of chronic diseases in the study population, and explore associations between work hours, fatigue, and 
health & quality of life outcomes.

Methods: We assessed the health impacts of extended shifts, shift rotation, and overtime among refinery workers using a self-reported health questionnaire administered to members of the United Steelworkers (N=17,333). Reported work schedules, annual estimates of overtime worked, typical sleep schedules and an evaluation of sleep quality were used to estimate fatigue exposure. Self-reported diagnoses of heart disease, hypertension, diabetes, and gastro-intestinal illness were used to calculate disease prevalence within the workforce. Calculated disease prevalence rates were compared to day shift workers from the surveyed population, rotating shift workers in other industries, and the general public. Job stress and quality of life indicators were measured, and a depression assessment was performed.

Results: A shift work exposure index will be calculated based on the exposure to alternate and rotating shift assignments (self-reported work schedules, annual overtime estimates, and work histories). Then an overall fatigue index will be calculated based on associations between hours worked, hours slept and sleep quality scores. These two exposure indices will be tested against individual health outcomes. Disease prevalence will be calculated based on self-reported assessment of current health symptoms and biometrics, and known medical diagnoses. Responses will be coded according to NHANES codebooks for CVD, diabetes, and blood pressure. Likert scales will be used to assess severity of job stress, depression, and quality of life factors, then scored to yield a positive or negative overall result.

Conclusions: The mechanisms of chronic diseases associated with fatigue are poorly understood. The direct effect of shift work on blood pressure, BMI, CVD and metabolic disease is debated. Recent research indicates that metabolic disease could be the primary causal mechanism for hypertension, CVD, and diabetes among shift workers. Our study has accessed a large workforce with a significant exposure to work related fatigue. Our detailed assessment of their past and current exposure, recovery periods, and health and mental status will generate valuable insights.

SR-118-09 New Results from the Comprehensive Lead Education and Reduction by Window Replacement (CLEAR-WIN) Program in Illinois

D. Jacobs, M. Tobin, P. Pratap, S. Cali, University of Illinois at Chicago, Chicago, ILD. Clarkson, Peoria Health Department, Peoria, IL; S. Dixon, National Center for Healthy Housing, Washington, D.C.; J. Breysse, National Center for Healthy Housing, Washington, D.C.

Objective: Childhood lead poisoning remains a widespread problem, with over half a million children having blood lead levels above the CDC reference value of 5 µg/dL. Windows are known to have the highest levels of both lead paint and lead dust compared to other building components, but large-scale window replacement programs have not been forthcoming and financed. This study was conducted to measure lead and other health outcomes associated with large scale replacement of old windows contaminated with lead.

Methods: Dust lead on floors, interior window sills and exterior window troughs, as well as resident health interviews was conducted in 50 housing units in Chicago (urban) and another 50 units in Peoria (rural). Dust lead was collected using the standard HUD wipe method and analyzed in an accredited laboratory. Health interviews were conducted using questions drawn from the CDC National Health Interview Survey.

Results: Preliminary results show geometric mean (GM) interior window sill dust lead loadings declined from 287 µg/ft2 to 32 µg/ft2 (89% reduction); exterior window troughs declined from 5,022 µg/ft2 to 120 µg/ft2 (98% reduction); and interior floors declined from 11.4 µg/ft2 to 9.7 µg/ft2 (15% reduction). Health interviews suggest there are also important health improvements associated with asthma and mental health. The data also show significant improvements in energy use and property value.

Conclusions: The findings suggest that replacement of lead painted windows can substantially reduce children’s exposure and illustrate the importance of establishing large-scale window replacement with state, federal and local financing mechanisms.

SR-118-10 Drying Water-Damaged Materials Based on Water Activity

E. Light, R. Gay, Building Dynamics, LLC, Ashton, MD; B. Carter, Decagon, Pullman, WA

Objective: Water damage restoration currently tracks drying by moisture content measured with moisture meters. Water activity is more specifically tied to potential for mold growth, but field measurement of construction materials for this parameter has not been feasible. This study monitored the drying of wet construction materials to compare moisture content with water activity.

Methods: Prototype instrumentation was used to track drying of wood by water activity side-by-side with a moisture meter

Results: It took approximately three times longer to dry wood to a water activity level considered sufficient to prevent fungal growth when compared to drying time needed to meet acceptable moisture content. Water activity remained at a level potentially supporting fungal growth after drying criteria in current use were met. Similar results have recently been published by another investigator using the same method to track the drying of gypsum board. .

Conclusions: Preliminary data suggest a potential for mold growth after re-installation of construction materials on surfaces meeting drying objectives based on moisture content. Research is needed to determine if reconstruction of sites with elevated water activity actually promotes mold growth.

SR-118-11 Distribution and Influence Factors for Knee and Hip Injuries among Retired Workers of Automotive Manufacturing

W. Chen, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China

Objective: Few researches reported the prevalence of injuries for knee and hip joint among workers in automotive manufacturing. The objective of this study was to describe distribution of knee and hip injuries among retired workers and to evaluate the possible factors which related to this damage.

Methods: The total of 9418 workers were involved in this study. Trained investigators collected information for all participants through one questionnaire. The data included personal information, work history and net years in work, self-reported injuries of the knee and hip. All participants took physical health examination including joint examination after the survey. Univariate and multivariate logistic analysis were conducted using SAS9.2.

Results: The average age of 9418 workers (4350 males, 46.2%) was 61.6±7.4 years old. The prevalence of the self-reported knee damage, clinical positive knee injuries and knee osteoarthritis were 40.9%, 3.7% and 7.5%. The prevalence of the self-reported hip damage, clinical positive hip injuries and hip osteoarthritis were 11.2%, 9.5% and 0.8%. High body mass index (BMI), job title and shift work were risk factors for knee injuries. BMI, job title and age were thought to be related with hip injuries. Loss years of service for workers with knee injuries and hip injuries were 8.8±5.5 years and 8.2 ±5.6 years, separately. Both were statistically significantly longer than those of workers without knee or hip injuries (6.5±6.0 years).

Conclusions: High prevalence of knee or hip injuries were observed among retired workers of automotive manufacturing. BMI number, special job title and age were possible risk factors for knee and hip injuries.

SR-118-12 Absent vs. Present but Not Quantified: Can a Job-Exposure Matrix Be Used to Predict Samples Where Lead Exposure is Likely Absent in U.S. OSHA Inspection Measurements?

J. Hwang, NIH, Bethesda, MD; J. Lavoué, University of Montreal, QC, Canada; S. Locke, D. Russ, C. Johnson, M. Friesen, NIH, Bethesda, MD