F. Boelter, C. Simmons, Boelter & Yates, Inc., Park Ridge, IL; L. Berman, University of Illinois, Chicago, IL.
Ten years of fiber release studies involving a variety of asbestos-containing fluid sealing devices (aka gaskets and packing) were compiled in a database and assessed. Studies were performed in actual field conditions or in an isolation chamber, both under “worst case” exposure scenarios of minimal to no ventilation using dry removal practices and a variety of typical and aggressive techniques. One hundred full-shift personal and 313 full-shift area time-weighted average (TWA) sample results were included in the database, along with 309 short-term (30-minute) sample results. The averaged personal TWA samples ranged from 0.004 to 0.084 total f/cc, with a mean of 0.026 total f/cc by phase contrast microscopy (PCM) and ranged from 0.003 to 0.024 asbestos f/cc, with a mean of 0.009 asbestos f/cc by transmission electron microscopy (TEM). The averaged area TWA samples ranged from 0.002 to 0.079 total f/cc, with a mean of 0.024 total f/cc by PCM and ranged from 0.003 to 0.028 asbestos f/cc, with a mean of 0.009 asbestos f/cc by TEM. The personal EL samples ranged from 0.041 to 0.94 total f/cc, with a mean of 0.086 total f/cc by PCM and ranged from 0.041 to 0.940 asbestos f/cc, with a mean of 0.058 asbestos f/cc by TEM. In addition, regardless of the level of the aggressive technique used to remove gaskets and packing, perceived increased energy for removal did not correspond with higher airborne asbestos fiber concentrations. As a whole, the data were significantly below the 8-hour Occupational Safety and Health Administration (OSHA) permissible exposure limit of 0.1 f/cc and the 30-minute excursion limit of 1 f/cc.
P. Sheehan, Exponent, Oakland, CA; F. Mowat, R. Wiedling, Exponent, Menlo Park, CA.
Asphalt-based roofing products containing chrysotile asbestos fibers were historically widely used in the United States to coat and seal roofs. An exposure simulation was conducted to evaluate the release of asbestos fibers associated with the manipulation of fiber coating and plastic roof cement products. During the simulated hand scraping and sanding of the product from roof substrates (likely rare activities) and scraping from representative clothing and representative tools, samples of airborne fibers were collected in a clean-room environment and analyzed for fibers with both phase contrast microscopy (PCM) and transmission electron microscopy (TEM). For both products, a total of 24 samples each were collected and analyzed for fibers. Asbestos concentrations (all fibers, including nonasbestos) measured by PCM ranged from below the limit of detection (<0.005 f/cc) to 0.017 f/cc. For all activities and replicates evaluated, no airborne asbestos fibers were found by TEM analyses in 14 of the 24 samples, one to six asbestos fibers were found in eight of the samples, and two samples contained 12 and 13 asbestos fibers, respectively. The estimated eight-hour TWAs ranged from 0.0003 to 0.001 f/cc based on one-half hour of activity in an eight-hour workday for the four activities evaluated in this exposure simulation. For the fibered coating product, airborne fiber concentrations (all fibers, including nonasbestos) measured by PCM ranged from below the limit of detection (<0.006 f/cc) to 0.019 f/cc. For all activities and replicates evaluated, no airborne asbestos fibers were found in 14 of the 24 samples, one to two asbestos fibers were found in five samples, and two samples contained five and 10 asbestos fibers, respectively. The estimated 8-hour TWAs for the fibered coating ranged from 0.0003 to 0.001 f/cc based on one-half hour of activity in an eight-hour workday for the four activities evaluated in this exposure simulation.
T. Anderson, CH2M HILL Hanford Group, Richland, WA.
The Hanford Site in eastern Washington produced plutonium for the United States’ nuclear weapons program from the 1940s to the 1980s. Nuclear and chemical waste from plutonium production was initially transferred to 149 single-shell underground storage tanks, each holding up to one million gallons of waste. In later years, waste was transferred to 28 newer double-shell tanks. The double-shell tanks were constructed by the U.S. Department of Energy in the 1970s and 1980s to provide more secure interim storage until the waste could be treated for stable long-term disposal. Tank farm contractors are in the process of retrieving all remaining waste from the older single-shell tanks and transferring it into the newer double-shell tanks. During the waste retrieval process, tank farms workers are potentially exposed to fugitive chemical vapors that can escape from tank headspaces. Preliminary investigations have shown that the tanks hold more than 1,800 different species of chemicals, in addition to radionuclides. Exposure assessments were undertaken to fully characterize the hazards from chemical vapors. This paper describes the extensive work that was done to characterize tank wastes, tank headspace vapors, and workplace vapor concentrations. Key elements of the evaluation are discussed, including 1.) Occupational exposure limit estimation and analytical method development for more than 1,400 of the chemicals which do not have established legal exposure limits and are not commonly measured in the field, 2.) Field sampling to evaluate the exposure potential, and 3.) Selection of controls for worker protection from the complex chemical mixtures. Sampling methods and results are discussed in detail.
S. Paik, R. Prodans, Abbott Laboratories, Abbott Park, IL.
The goal of this study was to evaluate the effectiveness of a flexible enclosure system designed to minimize exposure of workers to potent pharmaceutical compounds during a raking operation inside a filter dryer. To aid this evaluation, a video exposure monitoring technique was developed utilizing video editing software, video conversion hardware and software, a digital camcorder, and a real-time aerosol monitor. The video exposure monitoring tool was used to identify when the greatest exposures occurred during the operation, which helped identify which part of the enclosure system needed improvements. Before the enclosure was installed, a peak relative mass concentration of 14884 µg/m3 was observed near the filter dryer door during raking. To reduce these concentrations, an enclosure was installed between the filter dryer door and chamber. The enclosure system included a rake attached through the enclosure which allowed the operator to perform the activity. With the enclosure system in place, measurements indicated a peak concentration of 1630 µg/m3 during the raking activity. A review of the data and concurrent video showed that these peaks mainly occurred when the operator was aggressively scraping the inside of the filter dryer. Inspection of the enclosure showed that holes indeed had formed near the area of the enclosure where the rake was attached. To minimize the potential for tearing the bag, the rake attachment was covered with foam insulation and a stool was placed on the floor to improve posture and visibility. With these additional improvements in place, measurements indicated a peak concentration of 68.7 µg/m3. This was significantly lower than any previous results and suggests that the modified rake and stool significantly improved containment of the operation. This study demonstrates the many benefits of using video exposure monitoring to control hazardous processes and thus minimize potential exposure to potent compounds.
D. Regelbrugge, W. Williams, F. Holcomb, G. Crawford, B. Caddick, Boelter & Yates, Park Ridge, IL.
Mercury has historically been used in valves, switches, gauges, thermometers, barometers, science projects, etc. Due to malfunction, misuse or general carelessness mercury spills occur. Spills can occur in elementary schools, hospitals, universities, and in private residences. The chronic health affects of mercury exposure are well documented. When spills occur it is imperative that the extent of the spills be identified and remediated. The industrial hygienist is usually tasked with the role of identifying mercury spills and developing a remediation protocol. Several direct reading devices are available to identify where spills have occurred and remediation procedures for mercury are well documented however; criteria for determining if an area has been successfully remediated are not well established. The Agency for Toxic Substances and Disease Registry (ATSDR) has established a residential cleanup clearance concentration of 1 microgram per cubic meter of air (µg/m3) and a relocation action level of 10 µg/m3 as well as a workplace or commercial setting re-occupancy concentration of 3.0 µg/m3. This presentation will provide an overview of how the ATSDR guidelines were applied to determine if mercury remediation areas were successfully remediated. The presentation will describe the industrial hygienist’s role in at least two mercury remediation projects from spill identification, remediation planning and final testing. Successes, such as identifying mercury contamination underneath floor tile and pitfalls such as deciding which ATSDR guideline to apply will be discussed.
M. Sheehan, West Chester University, West Chester, PA; J. Galloway, Cephalon, West Chester, PA; J. Zanini, Becton, Dickinson and Company, Juiz de Fora, Brazil; N. Orr, G. Barbi, Becton, Dickinson and Company, Franklin Lakes, NJ.
Mercury vapor samples were collected over several years at a thermometer manufacturing plant in Brazil. As the plant capacity increased there were many challenges to address in order to protect workers in this facility. The purposes of this study were to use the air sampling data to determine patterns and factors that influence exposure, and to help elucidate some of the problems, solutions, variability, and limitations industrial hygienists can face when managing and interpreting these types of data. Air samples were taken by plant personnel several times daily in 27 areas using a Jerome 411 mercury vapor meter. The resulting dataset for 1988–1991 (N= 62,083) was evaluated for its distribution and descriptive statistics. The relationships among the individual air values, area of the plant, temperature, time of day, and month were investigated by regression and correlation and were graphically interpreted. More than 98% of the individual readings were below the NIOSH REL (TWA), 99.98% were below the OSHA PEL (TWA) and NIOSH REL (Ceiling) and 82.86%were less than the current TLV (TWA). Regression and correlation analysis of the natural log transformed data indicated that all of the independent variables were significant (r2 of 0.23; p < 0.001 level). Temperature had the least contribution to the total variance. Differences in concentration by area were associated with breakage and with contamination due to clothing and shoes. Diurnal variations in concentration were associated with cleaning and may have been due to HVAC cycling. Monthly levels were associated with breakage and not usually with high production months. Our study indicates that production problems and their solutions can be very important factors influencing mercury vapor concentrations. Temporal data indicate that the dataset is not stationary and as a result may complicate further industrial hygiene analysis such as comparisons with biological monitoring data.
B. Pathak, CCOHS, Hamilton, ON, Canada; G. Rajhans, GSR Associates, Mississauga, ON, Canada.
The paper presents the issues related to the assessment of past occupational exposures. Industrial hygienists are often expected to retrospectively assess the exposure based on employment history of workers. Such data is of particular importance in determining work relatedness of occupational exposures to occupational illnesses and in preparation for expert testimony. Occupational hygienists may have to estimate past exposures occurring in a number of employment situations and in some cases, exposures occurring in different countries. We will present a review of the significant issues in estimating such exposures and what types of data may occupational hygienists rely upon to formulate professional opinion. We will specifically address the following questions:
L. Snyder, J. Kolcun, GE Transportation, Albuquerque, NM; R. Edgar, Weston Solutions, Inc., Albuquerque, NM.
Heavy metals, such as hexavalent chromium [Cr(VI)] have been recognized as potential or confirmed human carcinogens when inhaled in very small concentrations. An ANSI standard was developed and in place in 1946 which recommended the control of airborne Cr(VI) at 100 micrograms per cubic meter (µg/m3). OSHA has now passed a new standard that impacts general industry, construction, and shipyards requiring those areas where airborne Cr(VI) is at or above 1 µg/m3 to be controlled as a regulated area. The problem facing employers with processes using hexavalent chromium is that some corrosion control products using hexavalent chromium have, as yet, no known substitute and are used for preventing catastrophic safety problems resulting from corrosion of aircraft parts, the airborne concentrations of hexavalent chromium paints used in these processes can not be adequately controlled by engineering controls to maintain concentrations below the proposed action level(s), and processes with their associated regulated areas were defined using practical applied methods which will provide worker protection in compliance with the proposed standard. This presentation is a description of how General Electric used its “3P” program to minimize and eliminate the use of hexavalent chromium (including strontium chromate and zinc chromate) in its facilities to the extent possible, the historical and baseline air sampling and analytical methods that were used to define the regulated activities and hence areas, a comparison of the various analytical methods available for determining the airborne levels of Cr(VI) and the benefits and drawback of each, the sampling plan and results of analytical data collected and used in defining the regulated areas, and how the areas where Cr(VI) is used were changed or reorganized to minimize the potential for chromium exposure (the number or size of regulated areas) and maintaining worker protection in compliance with the proposed Cr(VI) standard, OSHA 1910.1026.
S. Erdal, University of Illinois at Chicago, Chicago, IL; L. Berman, University of Illinois, Chicago, Chicago, IL.
Limited number of studies have demonstrated that the occupational environment of metal sculptors/artist welders is poorly understood. A segment of the artist welder community can potentially be classified as a high-risk population due to their work practices, work environment, and lack of regulatory oversight. In order to support such hypothesis, we undertook a survey-based study, in which knowledge related to the work environment, exposure/risk parameters (e.g., exposure time, frequency, and duration), exposure behavior, health awareness, and exposure control practices of this unique subpopulation was ascertained. We administered the questionnaire to two separate sample populations. The first nonrandom sample population (Group 1) came from a database of sculptors whose sculptures are exhibited in public spaces across the United States. The second sample population (Group 2) originated from attendees of a two-day workshop in the tri-state area of North Carolina, South Carolina, and Virginia. The response rates of Group 1 and Group 2 were 81.6% (i.e., 93 of the 114 artists) and 79.5% (i.e., 35 of the 44 artists), respectively. About 41% of Group 1 and 37% of Group 2 artists reported welding more than eight hours/day when working at full capacity during a regular workweek. About 60% of Group 1 reported wearing respiratory protection while cutting, grinding, painting, applying coatings, sand-blasting, and welding only certain materials (bronze, galvanized Zn). In addition, while 47% of Group 1 artists indicated that artists were educated about controlling their exposure, an equal percentage (47%) disagreed. Our data indicate that a segment of this artist community may potentially be a high-risk population due to longer work hours and a lack of proper ventilation and exposure control measures. It is essential to reach the artist welder community with occupational health and safety training programs specifically tailored to their needs, in order to increase health hazard awareness related to their work practices.
Posted May 30, 2006