Journal of Occupational and Environmental Hygiene

Our medical research library holds 51 studies published in Journal of Occupational and Environmental Hygiene (2004–2026). Each entry links to the study's record on PubMed and, where there is one, to the publisher's page and a free full text. 43 have an abstract, the authors' own summary as PubMed records it: open "Abstract" to read it. For 1 study PubMed has no abstract for, we give the abstract printed in the article or, where there is none, a summary we wrote from it, each labeled as such.

About the journal

• Publisher: Informa Healthcare
• Published: 2004 to the present, England
• Language: English
• ISSN: 1545-9624 (print), 1545-9632 (electronic)
• Merged from: AIHA Journal
• Merged from: Applied Occupational and Environmental Hygiene
• Its record in the NLM Catalog

2020s

• Evaluating the interference potential of minerals in infrared absorbance-based quantification of respirable crystalline silica in mine dusts. D.A. Parks, S.A. Finley, P.M. Tjandra, et al. 2026;23(3):142-154. PubMed · Publisher · Free full text

  Abstract

  Miners face a variety of respiratory hazards on the job, including exposure to respirable crystalline silica (RCS), which can lead to adverse health outcomes such as silicosis and lung cancer-both potentially fatal lung diseases. Infrared spectrometry offers the possibility of portable end-of-shift quantification of RCS at mine sites. However, some mine dusts contain minerals that may interfere with this quantification method, as their infrared absorbance bands overlap with those of silica. To evaluate the impact of such interferences, potential mineral interferants were identified in the geologies of 27 metal mines using the United States Geological Survey and Mindat.org databases. These mines were selected based on historically high RCS levels, as evidenced in the Mine Safety and Health Administration (MSHA) field-sampling database, and on the number of employees potentially exposed. The significance of 44 potential interferants was evaluated using Fourier Transform Infrared spectroscopy (FT-IR), by measuring their absorbance per unit mass in the α-quartz doublet region of the spectrum (816-767 cm-1). The extent to which each mineral interfered with this region was quantified as its integrated absorbance relative to RCS. This quantification of interference provides data critical for the timely and portable quantification of RCS in mine dusts. Of the 44 specimens analyzed, three (goethite, azurite and actinolite), which are not mentioned in the standard infrared methods for quantification of RCS, were found to interfere with a magnitude of 10% or more. Despite being commonly mentioned as interferants in the literature, the feldspars Albite and Anorthite did not interfere with a magnitude of 10% or more.

• An alternative to the HSE/NPL Mark II Phase Contrast Test Slide for airborne asbestos fiber analysis laboratories. G. Pickford, J. Szymanska. 2025;22(5):425-436. PubMed · Publisher

  Abstract

  More than 55 years ago, an analytical method employing phase contrast optical microscopy was developed for the quantitative estimation of airborne asbestos fiber concentration, and it was found that the detection limit of these microscopes was dependent upon microscope design, microscope set-up, and observer performance. In the early 1980s, the HSE/NPL Mark II Phase Contrast Test Slide was developed which facilitated standardizing detection limits of microscopes and observers in laboratories around the world. This paper describes the development and testing of an alternative test slide, known as the Pickford Phase Contrast Test Slide, which employs state-of-the-art nano-fabrication technology. Each Pickford Test Slide is certified by the Environmental Analysis Laboratory of the Southern Cross University stating that it is equivalent in performance to that of the HSE/NPL Mark II test slide, which aligns with the United Kingdom Health and Safety Executive HSG248 Asbestos: The Analysts' Guide (2021) requirement. Users report that the Pickford Test Slide is much easier to use than the HSE/NPL Slide. Since the early 1980s, the certification of phase contrast microscope test slides has been based on subjective visibility testing, which is less than ideal because of variations between certifiers, reference standards, and microscopes. Hence, a unique objective visibility test was developed with the aim of replacing subjective testing, and also of conducting routine testing of the test slide phase objects following nano-fabrication. Routine testing has been useful because each Pickford Test Slide is tested and documented so that intricate nano-fabrication chip processes can be controlled over years of production. However, thousands of comparisons of both forms of testing have shown that it is very unlikely that objective visibility testing will ever replace subjective testing because valid and relevant objective testing depends upon standardizing several dozen microscope camera set-up parameters that vary from one camera to another. Further, because the ultimate use of a test slide has always been based on human visibility, validation may not be achievable.

• A review of occupational exposures to carcinogens among wildland firefighters. M. West, S. Brown, E. Noth, et al. 2024;21(10):741-764. Review PubMed · Publisher

  Abstract

  Wildfires can negatively impact the health and well-being of wildland firefighters through a variety of exposure pathways. Many studies have measured acute health effects from occupational exposure to pollutants in wildfire smoke; however, research specifically examining cancer risks from exposure to carcinogens is limited. This review aimed to better understand cancer risk in this occupation by assessing the existing evidence of exposures and summarizing measured concentrations of carcinogens among wildland firefighters. A systematic search was conducted to identify scientific papers using the following databases: Medline(OVID), Embase(OVID), PsycINFO(OVID), Cochrane Library, CINAHL(EBSCOHost), EconLit(EBSCOHost), Scopus, Agricultural and Environmental Science Collect(ProQuest), and NIOSHTIC-2. Forty-nine papers were identified that met eligibility criteria. Across the papers, 31 carcinogens were identified and quantified using a variety of assessment methods. Papers measured particulate matter (N = 26), polycyclic aromatic hydrocarbons (N = 12), volatile organic compounds (N = 14), crystalline silica (N = 5), black carbon (N = 4), asbestos (N = 3), radionuclides (N = 7), and metals (N = 2). Most papers measured inhalation exposures through traditional air sampling methods, but a subset of exposures to polycyclic aromatic hydrocarbons (N = 8), as well as heavy metals (N = 1), were measured through urinary biomarkers and naphthalene was measured using dermal wipe samples (N = 2). Although the heterogeneity of exposure assessment methods made direct comparison of concentrations difficult, the papers provide consistent evidence that wildland firefighters are regularly exposed to carcinogens. All wildland fire personnel should continue to implement recommended mitigation strategies and support new mitigations to reduce exposure to carcinogens on the job.

• Occupational exposures to asbestos in the steel industry: An analysis of the AISI sampling campaign (1989-1997). M.E. Stevens, D.W. Brew, D.J. Paustenbach. 2024;21(6):439-449. Review PubMed · Publisher

  Abstract

  The American Iron and Steel Institute (AISI) gathered data between 1989 and 1997 to build an "objective database" to further understand the occupational exposures generated by the few asbestos-containing materials remaining at various steelmaking companies at this time. This paper analyzed the 520 samples from this campaign which occurred at five different steel manufacturers: Georgetown Steel Company, Inland Steel Company, Ling-Temco-Vought (LTV) Corporation, United States Steel Corporation, and Weirton Steel Corporation. This database is believed to have never previously been systematically organized. Samples were grouped based on sampling times to determine whether they should most appropriately be compared to the OSHA short-term excursion limit (EL) or the 8-hr time-weighted average (TWA) permissible exposure limit (PEL). Sampling times of 30 min or less were considered short-term samples, and samples of 180 min or greater were considered representative workday samples. Samples that did not fit into either category, with sampling times between 31 and 179 min, were considered task samples. Overall, the data indicated that the airborne concentrations were quite low in 1989 and they continued to be low through the study period which ended in 1997. Only seven out of 286 (approximately 2.5%) short-term or representative workday samples were in exceedance of the current OSHA OELs that were implemented in 1994 (short-term samples being compared to the 1 f/cc EL and representative workday samples being compared to the 0.1 f/cc 8-hr TWA PEL). Consistent with prior data, analysis of this dataset supports the view that materials containing asbestos were not used in many applications in the steel industry, and measured airborne concentrations of asbestos were almost always below the occupational exposure limits (OELs) in the post-OSHA era (1972-2000).

• Asbestos exposure and small cell lung cancer: Systematic review and meta-analysis. T. Curiel-García, J. Rey-Brandariz, L. Varela-Lema, et al. 2023;20(10):427-438. Meta-analysis · Systematic review PubMed · Publisher

  Abstract

  Asbestos is a mineral that is carcinogenic to humans. Its use has been banned in many occidental countries yet it is still produced in the United States, and materials that contain asbestos remain in many occupational settings and indoor environments. Even though asbestos carcinogenicity is well known, there is scant literature on its specific effects regarding small cell lung cancer (SCLC). We therefore conducted a systematic review and meta-analysis to determine SCLC risk among workers exposed to asbestos. A systematic search of the literature was conducted to identify studies which reported occupational exposure to asbestos and SCLC-related deaths and/or incidence. We identified seven case-control studies that included 3,231 SCLC cases; four studies reported smoking-adjusted risks. A significantly increased risk of SCLC (pooled OR 1.89; 95% CI, 1.25-2.86) was observed on pooling studies on men (six studies) that displayed moderate heterogeneity (I2 = 46.0%). Overall, our synthesis suggests that occupational exposure to asbestos significantly increases the risk of SCLC on men.

• Asbestos fiber length and width comparison between manual and semi-automated measurements. T. Lee, T. Barone, E. Rubinstein, et al. 2022;19(6):370-380. PubMed · Publisher

  Abstract

  The objective of the present study is to find a fast and accurate procedure to measure the length and width of asbestos fibers using images acquired by a scanning electron microscope (SEM), a phase-contrast microscope (PCM), and a polarized light microscope (PLM). The accuracy of the procedure was evaluated by comparing fiber length and width measurements to manual measurements. Four different types of images were used in the evaluation: (1) backscattered electron SEM images of fibrous tremolite, (2) secondary electron SEM images of fibrous grunerite, (3) PCM images of fibrous grunerite, and (4) PLM images of fibrous grunerite. Fiber length and width were measured with ImageJ (manual measurement) and Image-Pro software and were compared on an individual fiber basis and over the number-length and number-width distribution of each sample. The results of the comparison showed that the individual length and width measurements with ImageJ and Image-Pro software had a nearly 1:1 relationship except for the width measurement in PLM images (8% of the variance in ImageJ width measurements was not explained by Image-Pro width measurements). Similarly, the number-length distributions were not significantly different (p > 0.05) between ImageJ and Image-Pro, but the number-width distributions were significantly different (p < 0.05) for PLM and secondary electron SEM images. Although the image analysis procedure for measuring fiber length and width with Image-Pro is not a fully automated procedure and still requires some manual intervention, it can be a more efficient and equally accurate alternative to time-consuming manual fiber length and width measurements for well dispersed fibers with high aspect ratios.

• Mobilization of asbestos fibers by weathering of a corrugated asbestos cement roof. T. Ervik, S. Eriksen Hammer, P. Graff. 2021;18(3):110-117. PubMed · Publisher

  Abstract

  Mobilization of asbestos fibers from a 60-year-old corrugated asbestos cement roof was studied in material samples collected from a domestic house in Southern-Norway. Samples included pieces of the roof itself, rainfall simulated run off-water and moss growing on the roof surface. Weathered roof debris below the rain water system was investigated for asbestos fibers leached from the roof, and air samples were collected for asbestos concentrations in ambient air. Micrographs obtained by scanning electron microscopy show that weathering exposed asbestos fibers on the deteriorated roof surface. A high number of fibers found in the run off-water as well as in the weathered roof debris sample illustrates that exposed fibers are prone to mobilization. Investigation of weathering-induced magnesium depletion by scanning electron microscopy energy dispersive X-ray spectroscopy of asbestos fibers collected from the moss, roof underside and surface revealed that fibers had MgO weight % comparable to reference material. The major element chemistry of the fibers is therefore unaltered. Our findings demonstrate that care must be taken when working on and handling old corrugated asbestos cement roof as asbestos fibers might be released. In order to limit exposure to mobile fibers, moss covering asbestos cement roof should not be removed.

2010s

• Accuracy of a mobile app to identify suspect asbestos-containing material in Australian residential settings. M.H. Govorko, L. Fritschi, A. Reid. 2018;15(8):598-606. PubMed · Publisher

  Abstract

  In situ asbestos in the built environment is a remaining source of exposure in countries that have prohibited the manufacture and use of asbestos. However, it is difficult to identify in situ asbestos-containing material in residential settings. The objective of this study was to evaluate the accuracy of the mobile phone application ("app"), ACM Check, in identifying in situ asbestos located inside and outside of homes compared with onsite inspections conducted by an experienced environmental consultant. A cross-sectional study was undertaken that involved participants completing ACM Check on their homes built pre-1990 and located throughout metropolitan Perth, Western Australia, and an onsite inspection conducted at each home by an environmental consultant. Cohen's kappa statistic was calculated to evaluate the strength of agreement between the two methods. The 40 houses sampled were built between 1898 and 1988 with a median year of 1966. Thirty-eight (95%) homes had at least one type of material categorized as positive for asbestos by both ACM Check and the environmental consultant (κ = 1.00). Agreement between the two methods differed when categorizing specific materials as positive or negative for asbestos with substantial agreement for fencing (κ = 0.918), outbuilding walls (κ = 0.844), backing board to electrical meter box (κ = 0.826), exterior wall cladding (κ = 0.771), and interior walls (κ = 0.754), and fair agreement for outbuilding roofs (κ = 0.375) and interior flooring (κ = 0.304). ACM Check is a tool that can be used by tradespeople, home renovators, and householders to screen residential settings for the presence of in situ asbestos-containing material. Mobile phone apps have the potential to be developed or modified for use in other countries to help users identify asbestos and reduce their risk of asbestos exposure.

• Assessing occupational erionite and respirable crystalline silica exposure among outdoor workers in Wyoming, South Dakota, and Montana. C. Beaucham, B. King, K. Feldmann, et al. 2018;15(6):455-465. PubMed · Publisher

  Abstract

  Erionite is a naturally occurring fibrous mineral found in many parts of the world, including the western United States. Inhalational exposure to erionite fibers in some localities is associated with health effects similar to those caused by asbestos exposure, including malignant mesothelioma. Therefore, there is concern regarding occupational exposures in the western United States. Currently, there are no standard sampling and analytical methods for airborne erionite fibers, as well as no established occupational exposure limits. Due to the potential adverse health effects, characterizing and minimizing exposures is prudent. Crystalline silica also occurs naturally in areas where erionite is found, principally as the mineral quartz. Work activities involving rocks containing quartz and soils derived from those rocks can lead to exposure to respirable crystalline silica (RCS). The typically dry and dusty environment of the western United States can increase the likelihood of exposures to aerosolized rocks and soils, but inhalation exposure is also possible in more humid conditions. In this case study, we describe several outdoor occupational environments with potential exposures to erionite and RCS. We describe our method for evaluating those exposures and demonstrate: (1) the occurrence of occupational exposures to airborne erionite and RCS, (2) that the chemical make-up of the erionite mineral can be determined, and (3) that effective dust control practices are needed to reduce employee exposures to these minerals.

• Assessment of occupational exposure to asbestos fibers: Contribution of analytical transmission electron microscopy analysis and comparison with phase-contrast microscopy. C. Eypert-Blaison, A. Romero-Hariot, F. Clerc, et al. 2018;15(3):263-274. PubMed · Publisher

  Abstract

  From November 2009 to October 2010, the French general directorate for labor organized a large field-study using analytical transmission electron microscopy (ATEM) to characterize occupational exposure to asbestos fibers during work on asbestos containing materials (ACM). The primary objective of this study was to establish a method and to validate the feasibility of using ATEM for the analysis of airborne asbestos of individual filters sampled in various occupational environments. For each sampling event, ATEM data were compared to those obtained by phase-contrast optical microscopy (PCOM), the WHO-recommended reference technique. A total of 265 results were obtained from 29 construction sites where workers were in contact with ACM. Data were sorted depending on the combination of the ACM type and the removal technique. For each "ACM-removal technique" combination, ATEM data were used to compute statistical indicators on short, fine and WHO asbestos fibers. Moreover, exposure was assessed taking into account the use of respiratory protective devices (RPD). As in previous studies, no simple relationship was found between results by PCOM and ATEM counting methods. Some ACM, such as asbestos-containing plasters, generated very high dust levels, and some techniques generated considerable levels of dust whatever the ACM treated. On the basis of these observations, recommendations were made to measure and control the occupational exposure limit. General prevention measures to be taken during work with ACM are also suggested. Finally, it is necessary to continue acquiring knowledge, in particular regarding RPD and the dust levels measured by ATEM for the activities not evaluated during this study.

• Capture efficiency of portable high-efficiency air filtration devices used during building construction activities. D.A. Newcomer, P. LaPuma, R. Brandys, et al. 2018;15(4):285-292. PubMed · Publisher

  Abstract

  The portable high-efficiency air filtration (PHEAF) device is used to control particulate matter (PM) generated from construction-type activities occurring within the built environment. Examples of activities where PHEAF devices are mobilized include building renovation, asbestos abatement, remediation of microbial contamination, and lead-based paint projects. Designed for use on short-term, temporary projects the PHEAF device captures airborne PM using a high-efficiency particulate air (HEPA) filter. This study sought to evaluate the capture efficiency of the PHEAF device in a field setting. An aerosol generator and photometer were used to measure particle penetration through 85 PHEAF devices. Average overall capture efficiency ranged from 41.78% to ≥99.97% with more than 88% of the tests failing to achieve 99.97% capture efficiency. Approximately 73% of the PHEAF device sample population failed to demonstrate HEPA performance criteria during any test round. A higher occurrence of PM concentrations measured around the perimeter of the filter suggested the presence of bypass leakage. While PHEAF devices were effective in capturing a significant quantity of aerosol test agent, these findings suggest that routine testing of the PHEAF device should be conducted to validate performance.

• Releasability of asbestos fibers from weathered roof cement. A.F. Oberta, L. Poye, S.P. Compton. 2018;15(6):466-473. PubMed · Publisher

  Abstract

  Chrysotile asbestos fibers were added to roofing products, including roof cement, for several decades. The fibers were described as "encapsulated" and therefore incapable of being released, an assertion that is disproved by the study reported herein. Three test panels of roof cement from the original container were exposed to ambient weathering in 2015 and 2016. Two panels were then sampled using the ASTM D5755 microvacuum method. Sampling revealed a light brown sub-layer under the dark brown surface layer, both of which crumbled and became friable during sampling. Analysis of the microvacuum samples with transmission electron microscopy showed that the material on the 2 panels contained 4,432,000 and 3,320,000 asbestos structures per cm² with nearly all of the structures consisting of fibers less than 5 µm long. Energy dispersive spectrometry determined that none of the fibers reported were coated with asphalt. The presence of free fibers was confirmed by direct examination of the surfaces of the panels and of dust released from handling the panels via scanning electron microscopy. This study confirmed the releasability of uncoated asbestos fibers from dried roof cement that was indicated in 2 previous studies published in 2007 and 2010. These results suggest that the finding of the Fifth Circuit Court in 1997 that uncoated airborne asbestos fibers cannot be released from roof cement, and therefore do not present a potential exposure by inhalation, was erroneous in retrospect. The exemption of roof cement from regulation under the Occupational Safety and Health Administration Construction Industry Standard for asbestos by the Court should not be relied on by employers of workers who remove weathered asbestos-containing roof cement, and precautions should be taken against exposure to airborne asbestos fibers during this work.

• An examination of MCE filter morphology and implications on preparation and analysis of air samples for asbestos. M. Getman, J. Webber, S. Bowser. 2017;14(9):140-144. PubMed · Publisher

  Abstract

  Morphological imperfections of mixed-cellulose ester filters and their possible influence on sample preparation and analysis of asbestos were examined. Filters were identified with large regions of non-porous "dead zones" which could negatively affect fiber deposition and, therefore, fiber recovery and analysis by Transmission Electron Microscopy (TEM). As these imperfections are effectively erased during the preparation of the sample, they may not be readily observed by TEM. Un-collapsed filters as well as those collapsed using dimethylformamide (DMF) and two acetone techniques were examined. In order to minimize negative sampling and analytical bias, it is suggested that MCE samples be collapsed utilizing a 35% DMF solution, etched with a correctly calibrated low-temperature etcher, carbon coated using a rotating and tilted stage, and analyzed with a strong analyst-independent grid square opening randomization scheme.

• Retracted. Airborne asbestos exposures associated with the installation and removal of roofing products. J.T. Lotter, B. Roberts, J.L. Henshaw, et al. 2016;13(8):D121-31. PubMed · Publisher

  Abstract

  Asbestos-containing roofing products were widely used throughout the 20th century, and certain products are still used in limited quantities today. Roofing products are generally considered non-friable and are not expected to release appreciable amounts of airborne asbestos fibers; however, despite the variety of roofing products that have contained asbestos over time, there are no comprehensive analyses of the exposure data associated with these products in the published literature. The objective of this study was to analyze the available data and characterize asbestos exposures associated with the installation, removal, and replacement of built-up roofing (BUR), felts, flashings, shingles, coatings, cements, and mastics under a variety of work practices. Published and unpublished literature that contained the following information was included in the analysis: (1) airborne fiber concentrations determined by PCM; (2) a description of the product(s) used; and (3) a description of the task(s) performed. More than 800 personal air samples from 12 studies performed between 1982 and 2010 were identified which fit the inclusion criteria. The findings indicate that short-term and full-shift exposures from the use of asbestos-containing roofing products were typically well below applicable occupational exposure limits. Additionally, the cumulative exposures associated with roofing work would be well below published chrysotile no-observed-adverse-effect-levels (NOAELs) for asbestos-related diseases.

• On the threshold conditions for electron beam damage of asbestos amosite fibers in the transmission electron microscope (TEM). J. Martin, M. Beauparlant, S. Sauvé, et al. 2016;13(12):924-935. PubMed · Publisher

  Abstract

  Asbestos amosite fibers were investigated to evaluate the damage caused by a transmission electron microscope (TEM) electron beam. Since elemental x-ray intensity ratios obtained by energy dispersive x-ray spectroscopy (EDS) are commonly used for asbestos identification, the impact of beam damage on these ratios was evaluated. It was determined that the magnesium/silicon ratio best represented the damage caused to the fiber. Various tests showed that most fibers have a current density threshold above which the chemical composition of the fiber is modified. The value of this threshold current density varied depending on the fiber, regardless of fiber diameter, and in some cases could not be determined. The existence of a threshold electron dose was also demonstrated. This value was dependent on the current density used and can be increased by providing a recovery period between exposures to the electron beam. This study also established that the electron beam current is directly related to the damage rate above a current density of 165 A/cm2. The large number of different results obtained suggest, that in order to ensure that the amosite fibers are not damaged, analysis should be conducted below a current density of 100 A/cm2.

• Retrospective Exposure Assessment for Occupational Disease of an Individual Worker Using an Exposure Database and Trend Analysis. D.A. Chung, R.R. Yang, D.K. Verma, et al. 2015;12(12):855-65. Historical article PubMed · Publisher

  Abstract

  This article outlines a hierarchy of data required for retrospective exposure assessment for occupational disease of an individual worker. It then outlines in a step-wise manner how trend analysis using a relatively large exposure database can be used to estimate such exposure. The process of how a large database containing exposure measurements can be prepared for estimating historic occupational exposures of individual workers in relation to their illnesses is described. The asbestos subset from a large government collected air monitoring database called Medical Surveillance (MESU) was selected to illustrate the cleaning and analysis processes. After unidentifiable values were removed, the cleaned dataset was examined for possible sources of variability such as changes to sampling protocol. Limit of detection (LOD) values were substituted for all non-detectable values prior to the calculation of descriptive statistic using left censored analysis methods (i.e., maximum likelihood estimation (MLE), Kaplan Meier (KM), and simple substitution). The JoinPoint Regression Program was used to perform trend analysis and calculate an annual percentage change (APC) value for the available sampling period. An asbestos case study is presented to illustrate how the APC can then be combined with more recent job and/or process specific exposure data to estimate historic levels. The MESU asbestos dataset contained 1,610 samples from 1984-1995. An average of 17% of this data was left censored. The asbestos air sampling methods in Ontario changed around 1990. LOD values of 0.06 f/cc and 0.02 f/cc were substituted for LOD values pre- and post-1990, respectively. The annual mean fiber levels for the MLE method were an average of 44% lower than KM and substitution methods. The corresponding APC for MLE method was -6.5% and -7.7% for KM and simple substitution. The findings of this paper illustrate how the temporal trend of an exposure databases can be used to efficiently estimate historic contaminant levels in the presence of limited historical information.

• Where occupation and environment overlap: US Forest Service worker exposure to Libby Amphibole fibers. M. Harper, C. Butler, D. Berry, et al. 2015;12(5):D47-53. PubMed · Publisher · Free full text

  Abstract

  The National Institute for Occupational Safety and Health (NIOSH) conducted an evaluation of exposures to asbestiform amphibole, known as Libby Amphibole (LA), to personnel from the US Department of Agriculture-Forest Service (USFS) working in the Kootenai National Forest near a former vermiculite mine close to Libby, Montana. LA is associated with vermiculite that was obtained from this mine; mining and processing over many years have resulted in the spread of LA into the surrounding Kootenai Forest where it has been found in tree bark, soil, and forest floor litter. As a result of this and other contamination, Libby and surrounding areas have been designated a "Superfund" site by the US Environmental Protection Agency (EPA). This article describes the application of EPA methods for assessing cancer risks to NIOSH sampling results. Phase-contrast microscopy for airborne asbestos fiber evaluation was found to be less useful than transmission electron microscopy in the presence of interfering organic (plant) fibers. NIOSH Method 7402 was extended by examination of larger areas of the filter, but fiber counts remained low. There are differences between counting rules in NIOSH 7402 and the ISO method used by EPA but these are minor in the context of the uncertainty in concentration estimates from the low counts. Estimates for cancer risk are generally compatible with those previously estimated by the EPA. However, there are limitations to extrapolating these findings of low risk throughout the entire area and to tasks that were not evaluated.

• The relationship between various exposure metrics for elongate mineral particles (EMP) in the taconite mining and processing industry. J. Hwang, G. Ramachandran, P.C. Raynor, et al. 2014;11(9):613-24. PubMed · Publisher

  Abstract

  Different dimensions of elongate mineral particles (EMP) have been proposed as being relevant to respiratory health end-points such as mesothelioma and lung cancer. In this article, a methodology for converting personal EMP exposures measured using the National Institute for Occupational Safety and Health (NIOSH) 7400/7402 methods to exposures based on other size-based definitions has been proposed and illustrated. Area monitoring for EMP in the taconite mines in Minnesota's Mesabi Iron Range was conducted using a Micro Orifice Uniform Deposit Impactor (MOUDI) size-fractionating sampler. EMP on stages of the MOUDI were counted and sized according to each EMP definition using an indirect-transfer transmission electron microscopy (ISO Method 13794). EMP were identified using energy-dispersive x-ray and electron diffraction analysis. Conversion factors between the EMP counts based on different definitions were estimated using (1) a linear regression model across all locations and (2) a location-specific ratio of the count based on each EMP definition to the NIOSH 7400/7402 count. The highest fractions of EMP concentrations were found for EMP that were 1-3 μm in length and 0.2-0.5 μm in width. Therefore, the current standard NIOSH Method 7400, which only counts EMP >5 μm in length and ≥ 3 in aspect ratio, may underestimate amphibole EMP exposures. At the same time, there was a high degree of correlation between the exposures estimated according to the different size-based metrics. Therefore, the various dimensional definitions probably do not result in different dose-response relationships in epidemiological analyses. Given the high degree of correlation between the various metrics, a result consistent with prior research, a more reasonable metric might be the measurement of all EMP irrespective of size. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: figures detailing EMP concentration.].

• Use of direct versus indirect preparation data for assessing risk associated with airborne exposures at asbestos-contaminated sites. M.P. Goldade, W.P. O'Brien. 2014;11(2):67-76. PubMed · Publisher

  Abstract

  At asbestos-contaminated sites, exposure assessment requires measurement of airborne asbestos concentrations; however, the choice of preparation steps employed in the analysis has been debated vigorously among members of the asbestos exposure and risk assessment communities for many years. This study finds that the choice of preparation technique used in estimating airborne amphibole asbestos exposures for risk assessment is generally not a significant source of uncertainty. Conventionally, the indirect preparation method has been less preferred by some because it is purported to result in false elevations in airborne asbestos concentrations, when compared to direct analysis of air filters. However, airborne asbestos sampling in non-occupational settings is challenging because non-asbestos particles can interfere with the asbestos measurements, sometimes necessitating analysis via indirect preparation. To evaluate whether exposure concentrations derived from direct versus indirect preparation techniques differed significantly, paired measurements of airborne Libby-type amphibole, prepared using both techniques, were compared. For the evaluation, 31 paired direct and indirect preparations originating from the same air filters were analyzed for Libby-type amphibole using transmission electron microscopy. On average, the total Libby-type amphibole airborne exposure concentration was 3.3 times higher for indirect preparation analysis than for its paired direct preparation analysis (standard deviation = 4.1), a difference which is not statistically significant (p = 0.12, two-tailed, Wilcoxon signed rank test). The results suggest that the magnitude of the difference may be larger for shorter particles. Overall, neither preparation technique (direct or indirect) preferentially generates more precise and unbiased data for airborne Libby-type amphibole concentration estimates. The indirect preparation method is reasonable for estimating Libby-type amphibole exposure and may be necessary given the challenges of sampling in environmental settings. Relative to the larger context of uncertainties inherent in the risk assessment process, uncertainties associated with the use of airborne Libby-type amphibole exposure measurements derived from indirect preparation analysis are low. Use of exposure measurements generated by either direct or indirect preparation analyses is reasonable to estimate Libby-type Amphibole exposures in a risk assessment.

• Thoracic fraction of inhaled fiber aerosol. Y.S. Cheng, W.C. Su. 2013;10(4):194-202. PubMed · Publisher

  Abstract

  Size-selective sampling is a health-related method to collect airborne particles based on penetration of inhaled particles into different regions of the human respiratory tract; thus, it is the most relevant sampling method to correlate health risks with occupational exposure. The current practice of sampling asbestos and other fibers is not a size-selective method. The thoracic size fraction, defined as the portion of inhaled particles that can penetrate through the larynx, has been suggested as the most relevant size-selective sampling method for fiber aerosol. The thoracic fraction is based on 1-deposition of inhaled spherical particles in the human extrathoracic airways for mouth breathing and corrected for the particle inhalability. There is no comparable information for fiber aerosols; therefore, there is no technical basis to ascertain whether the current thoracic fraction definition is suitable for fiber aerosols. No human data are available from controlled experiments of inhaled fiber aerosols for the obvious reason that most fiber materials are potentially hazardous when inhaled. Our approach was to measure penetration of fiber aerosol in realistic human oropharyngeal airway replicas and to compare that with data from spherical particles. We showed that realistic human oral airway replicas (including the oral cavity, pharynx, and larynx regions) provided useful spherical and fiber particle deposition in the human head airway. These data could be used to test the thoracic fraction curves. The spherical penetration is in agreement with human in vivo data used to establish the thoracic fraction curve. Fiber penetrations through the larynx of two human oral airway replicas were higher than those for spherical particles for the same aerodynamic diameter using the same replicas. The thoracic curve as defined for spherical particles, therefore, may not include some fibers that could penetrate to the thoracic region.

• A novel strategy for retrospective exposure assessment in the Norwegian silicon carbide industry. S. Føreland, M.D. Bugge, B. Bakke, et al. 2012;9(4):230-41. PubMed · Publisher

  Abstract

  The objective was to construct a retrospective job-exposure matrix (JEM) for the Norwegian silicon carbide industry. More than 3300 historical total dust measurements were available (1967-2005); however, there were few measurements of other agents. Total dust measurements were therefore used as the basis for the JEM, and a novel method was developed to estimate exposure to other agents. Multiple linear regression models were developed to describe historical exposure to total dust. Exposure estimates were extrapolated backward to periods without exposure data by adjustments for process and work-hour related changes. An exposure assessment study was performed where total dust was sampled in parallel with fibers or respirable dust. The respirable dust was analyzed for the content of quartz, cristobalite, and silicon carbide. Mixed-effect models were developed to estimate the exposure to these agents from total dust exposure, plant, and job group. Exposure to asbestos and polycyclic aromatic hydrocarbons was assigned qualitatively. Multiple linear regression models of total dust described historical exposure best in the furnace department (R(2) (adj) = 0.49-0.74). Models in the other departments explained less variance (R(2) (adj) = 0.12-0.32). Exposure determinants and total dust explained a substantial proportion of the between- (70-100%) and within-worker (8.0-54%) variance in the mixed-effect models. The relative bias between available historical measurements and the estimated exposure to dust components varied between -39% (fiber) and 40% (quartz). However, corrections were not considered necessary due to limitations in the historical data. The component-specific metrices were sufficiently different from each other (r(Pearson) < 0.7), with the exception of total and respirable dust (r(Pearson) = 0.84) and total dust and cristobalite (r(Pearson) = 0.72), and will enable component-specific epidemiologic analyses in the future. Improved and less correlated estimates of exposure levels for the different components in the dust were obtained with the updated exposure assessment. Due to limitations in the measurement data, assumptions had to be made, especially in the period before 1967. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a file containing tables outlining multiple linear regression models for prediction of total dust exposure in the processing departments of Norwegian SiC producing plants, evaluation of the predictive abilities of the reduced total dust models, and mixed models for pedicting exposure to fibers and respirable quartz, cristobalite, non-fibrous silicon carbide and respirable dust from total dust exposure.].

• Amphibole asbestos in tree bark--a review of findings for this inhalational exposure source in Libby, Montana. T.J. Ward, T.M. Spear, J.F. Hart, et al. 2012;9(6):387-97. Review PubMed · Publisher

  Abstract

  In June 2009, the U.S. Environmental Protection Agency (EPA) designated the town of Libby, Montana, a public health emergency--the first and only time the EPA has made such a determination under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). From about 1920 until 1990, the leading source of vermiculite ore for the United States and the world was from a mine near Libby. This vermiculite ore was contaminated with fibrous and asbestiform amphibole in veins throughout the deposit. Today, areas surrounding the abandoned vermiculite processing/mining facilities and much of the town of Libby are contaminated with these asbestos fibers, contributing to an outbreak of asbestos-related diseases in the Libby population. Trees in Libby and in forested areas surrounding the abandoned mine have accumulated amphibole asbestos fibers on their bark surface, providing for inhalational exposures. Several studies have been conducted to further understand this exposure pathway. To address exposures to the public, Libby amphibole (LA) was measured in personal breathing zone and Tyvek surface wipe samples collected during firewood harvesting simulations, as well as in the ash and emissions of woodstoves when amphibole-contaminated firewood was combusted. Occupational studies simulating wildland firefighting and routine U.S. Department of Agriculture (USDA) Forest Service activities have also been conducted in the forested areas surrounding the abandoned mine, demonstrating the potential for inhalational exposures during common regional workplace activities. We present a review of the findings of this emerging environmental health concern impacting not only the residents of Libby but applicable to other populations living near asbestos-contaminated areas.

• Asbestos fiber burden in lung tissues of occupationally exposed workers. D.K. Verma, N.E. Clark. 2012;9(10):D177-82. PubMed · Publisher

• Exposure data from multi-application, multi-industry maintenance of surfaces and joints sealed with asbestos-containing gaskets and packing. F. Boelter, C. Simmons, P. Hewett. 2011;8(4):194-209. PubMed · Publisher

  Abstract

  Fluid sealing devices (gaskets and packing) containing asbestos are manufactured and blended with binders such that the asbestos fibers are locked in a matrix that limits the potential for fiber release. Occasionally, fluid sealing devices fail and need to be replaced or are removed during preventive maintenance activities. This is the first study known to pool over a decade's worth of exposure assessments involving fluid sealing devices used in a variety of applications. Twenty-one assessments of work activities and air monitoring were performed under conditions with no mechanical ventilation and work scenarios described as "worst-case" conditions. Frequently, the work was conducted using aggressive techniques, along with dry removal practices. Personal and area samples were collected and analyzed in accordance with the National Institute for Occupational Safety and Health Methods 7400 and 7402. A total of 782 samples were analyzed by phase contrast microscopy, and 499 samples were analyzed by transmission electron microscopy. The statistical data analysis focused on the overall data sets which were personal full-shift time-weighted average (TWA) exposures, personal 30-min exposures, and area full-shift TWA values. Each data set contains three estimates of exposure: (1) total fibers; (2) asbestos fibers only but substituting a value of 0.0035 f/cc for censored data; and (3) asbestos fibers only but substituting the limit of quantification value for censored data. Censored data in the various data sets ranged from 7% to just over 95%. Because all the data sets were censored, the geometric mean and geometric standard deviation were estimated using the maximum likelihood estimation method. Nonparametric, Kaplan-Meier, and lognormal statistics were applied and found to be consistent and reinforcing. All three sets of statistics suggest that the mean and median exposures were less than 25% of 0.1 f/cc 8-hr TWA sample or 1.0 f/cc 30-min samples, and that there is at least 95% confidence that the true 95th percentile exposures are less than 0.1 f/cc as an 8-hr TWA.

• Potential artifacts associated with historical preparation of joint compound samples and reported airborne asbestos concentrations. G.P. Brorby, P.J. Sheehan, D.W. Berman, et al. 2011;8(5):271-8. PubMed · Publisher

  Abstract

  Airborne samples collected in the 1970s for drywall workers using asbestos-containing joint compounds were likely prepared and analyzed according to National Institute of Occupational Safety and Health Method P&CAM 239, the historical precursor to current Method 7400. Experimentation with a re-created, chrysotile-containing, carbonate-based joint compound suggested that analysis following sample preparation by the historical vs. current method produces different fiber counts, likely because of an interaction between the different clearing and mounting chemicals used and the carbonate-based joint compound matrix. Differences were also observed during analysis using Method 7402, depending on whether acetic acid/dimethylformamide or acetone was used during preparation to collapse the filter. Specifically, air samples of sanded chrysotile-containing joint compound prepared by the historical method yielded fiber counts significantly greater (average of 1.7-fold, 95% confidence interval: 1.5- to 2.0-fold) than those obtained by the current method. In addition, air samples prepared by Method 7402 using acetic acid/dimethylformamide yielded fiber counts that were greater (2.8-fold, 95% confidence interval: 2.5- to 3.2-fold) than those prepared by this method using acetone. These results indicated (1) there is an interaction between Method P&CAM 239 preparation chemicals and the carbonate-based joint compound matrix that reveals fibers that were previously bound in the matrix, and (2) the same appeared to be true for Method 7402 preparation chemicals acetic acid/dimethylformamide. This difference in fiber counts is the opposite of what has been reported historically for samples of relatively pure chrysotile dusts prepared using the same chemicals. This preparation artifact should be considered when interpreting historical air samples for drywall workers prepared by Method P&CAM 239.

  Copyright © 2011 JOEH, LLC

• Analytical performance issues. Two different methods, three different variations, four different sources: what bulk asbestos PLM method is your laboratory using? Part 2. D.B. McGrath, D.R. Van Orden, R.M. Howard, et al. 2010;7(9):D65-8. PubMed · Publisher

• Asbestos is still with us: repeat call. Collegium Ramazzini. 2010;7(8):D57-61. PubMed · Publisher

• Two different methods, three different variations, four different sources: what bulk asbestos PLM method is your laboratory using? Part 1. D.B. McGrath, D.R. Van Orden, R.M. Howard, et al. 2010;7(8):D53-6. PubMed · Publisher

2000s

• A review of changes in composition of hot mix asphalt in the United States. D.J. Mundt, K.M. Marano, A.P. Nunes, et al. 2009;6(11):714-25. Historical article PubMed · Publisher

  Abstract

  This review researched the materials, methods, and practices in the hot mix asphalt industry that might impact future exposure assessments and epidemiologic research on road paving workers. Since World War II, the U.S. interstate highway system, increased traffic volume, transportation speeds, and vehicle axle loads have necessitated an increase in demand for hot mix asphalt for road construction and maintenance, while requiring a consistent road paving product that meets state-specific physical performance specifications. We reviewed typical practices in hot mix asphalt paving in the United States to understand the extent to which materials are and have been added to hot mix asphalt to meet specifications and how changes in practices and technology could affect evaluation of worker exposures for future research. Historical documents were reviewed, and industry experts from 16 states were interviewed to obtain relevant information on industry practices. Participants from all states reported additive use, with most being less than 2% by weight. Crumb rubber and recycled asphalt pavement were added in concentrations approximately 10% per unit weight of the mix. The most frequently added materials included polymers and anti-stripping agents. Crumb rubber, sulfur, asbestos, roofing shingles, slag, or fly ash have been used in limited amounts for short periods of time or in limited geographic areas. No state reported using coal tar as an additive to hot mix asphalt or as a binder alternative in hot mix pavements for high-volume road construction. Coal tar may be present in recycled asphalt pavement from historical use, which would need to be considered in future exposure assessments of pavers. Changes in hot mix asphalt production and laydown emission control equipment have been universally implemented over time as the technology has become available to reduce potential worker exposures. This work is a companion review to a study undertaken in the petroleum refining sector that investigated current and historical use of additives in producing petroleum-derived asphalt cements.

• Changes in collection efficiency in nylon net filter media through magnetic alignment of elongated aerosol particles. C.O. Lam, W.H. Finlay. 2009;6(10):648-57. PubMed · Publisher

  Abstract

  Fiber aerosols tend to align parallel to surrounding fluid streamlines in shear flows, making their filtration more difficult. However, previous research indicates that composite particles made from cromoglycic acid fibers coated with small nanoscaled magnetite particles can align with an applied magnetic field. The present research explored the effect of magnetically aligning these fibers to increase their filtration. Nylon net filters were challenged with the aerosol fibers, and efficiency tests were performed with and without a magnetic field applied perpendicular to the flow direction. We investigated the effects of varying face velocities, the amount of magnetite material on the aerosol particles, and magnetic field strengths. Findings from the experiments, matched by supporting single-fiber theories, showed significant efficiency increases at the low face velocity of 1.5 cm s(-1) at all magnetite compositions, with efficiencies more than doubling due to magnetic field alignment in certain cases. At a higher face velocity of 5.12 cm s(-1), filtration efficiencies were less affected by the magnetic field alignment being, at most, 43% higher for magnetite weight compositions up to 30%, while at a face velocity of 10.23 cm s(-1) alignment effects were insignificant. In most cases, efficiencies became independent of magnetic field strength above 50 mT, suggesting full alignment of the fibers. The present data suggest that fiber alignment in a magnetic field may warrant applications in the filtration and detection of fibers, such as asbestos.

• Efficiency of sampling and analysis of asbestos fibers on filter media: implications for exposure assessment. D.A. Vallero, J.R. Kominsky, M.E. Beard, et al. 2009;6(1):62-72. PubMed · Publisher

  Abstract

  To measure airborne asbestos and other fibers, an air sample must represent the actual number and size of fibers. Typically, mixed cellulose ester (MCE, 0.45 or 0.8 microm pore size) and, to a much lesser extent, capillary-pore polycarbonate (PC, 0.4 microm pore size) membrane filters are used to collect airborne asbestos for count measurement and fiber size analysis. In this research study, chrysotile asbestos (fibers both shorter and longer than 5 microm) were generated in an aerosol chamber and sampled by 25 mm diameter MCE filter media to compare the fiber retention efficiency of 0.45 microm pore size filters vs. 0.8 microm pore size filter media. In addition, the effect of plasma etching times on fiber densities was evaluated. This study demonstrated a significant difference in fiber retention efficiency between 0.45 microm and 0.8 microm pore size MCE filters for asbestos aerosols (structures longer than or equal to 0.5 microm length). The fiber retention efficiency of a 0.45 microm pore size MCE filter is statistically significantly higher than that of the 0.8 microm pore size MCE filter. However, for asbestos structures longer than 5 microm, there is no statistically significant difference between the fiber retention efficiencies of the 0.45 microm and 0.8 microm pore size MCE filters. The mean density of asbestos fibers (longer than or equal to 0.5 microm) increased with etching time. Doubling the etching time increased the asbestos filter loading in this study by an average of 13%. The amount of plasma etching time had no effect on the filter loading for fibers longer than 5 microm. Many asbestos exposure risk models attribute health effects to fibers longer than 5 microm. In these models, both the 0.45 microm and 0.8 microm pore size MCE filter can produce suitable estimates of the airborne asbestos concentrations. However, some models suggest a more significant role for asbestos fibers shorter than 5 microm. Exposure monitoring for these models should consider only the 0.45 microm pore size MCE filters as recommended by the U.S. Environmental Protection Agency Asbestos Hazard Emergency Response Act (AHERA) protocol and other methods.

• Summary of retrospective asbestos and welding fume exposure estimates for a nuclear naval shipyard and their correlation with radiation exposure estimates. D.D. Zaebst, E.A. Seel, J.H. Yiin, et al. 2009;6(7):404-14. Historical article PubMed · Publisher

  Abstract

  In support of a nested case-control study at a U.S. naval shipyard, the results of the reconstruction of historical exposures were summarized, and an analysis was undertaken to determine the impact of historical exposures to potential chemical confounders. The nested case-control study (N = 4388) primarily assessed the relationship between lung cancer and external ionizing radiation. Chemical confounders considered important were asbestos and welding fume (as iron oxide fume), and the chromium and nickel content of welding fume. Exposures to the potential confounders were estimated by an expert panel based on a set of quantitatively defined categories of exposure. Distributions of the estimated exposures and trends in exposures over time were examined for the study population. Scatter plots and Spearman rank correlation coefficients were used to assess the degree of association between the estimates of exposure to asbestos, welding fume, and ionizing radiation. Correlation coefficients were calculated separately for 0-, 15-, 20-, and 25-year time-lagged cumulative exposures, total radiation dose (which included medical X-ray dose) and occupational radiation dose. Exposed workers' estimated cumulative exposures to asbestos ranged from 0.01 fiber-days/cm(3) to just under 20,000 fiber-days/cm(3), with a median of 29.0 fiber-days/cm(3). Estimated cumulative exposures to welding fume ranged from 0.16 mg-days/m(3) to just over 30,000 mg-days/m(3), with a median of 603 mg-days/m(3). Spearman correlation coefficients between cumulative radiation dose and cumulative asbestos exposures ranged from 0.09 (occupational dose) to 0.47 (total radiation dose), and those between radiation and welding fume from 0.14 to 0.47. The estimates of relative risk for ionizing radiation and lung cancer were unchanged when lowest and highest estimates of asbestos and welding fume were considered. These results suggest a fairly large proportion of study population workers were exposed to asbestos and welding fume, that the absolute level of confounding exposure did not affect the risk estimates, and that weak relationships existed between monitored lifetime cumulative occupational radiation dose and asbestos or welding fume.

• Analysis of the analytical performance of laboratories participating in two major U.S. bulk asbestos proficiency testing programs. B.W. Harvey, W.G. Winstead. 2008;5(7):455-62. PubMed · Publisher

  Abstract

  Quality assurance and proficiency testing programs have been available for 27 years for U.S. laboratories using polarized light microscopy to analyze bulk building materials for asbestos. Total enrollment in the two principal bulk asbestos proficiency testing programs conducted by RTI International peaked at nearly 900 laboratories in the mid-1990s. Enrollment has stabilized in the last 5 years at approximately 475 laboratories, and rates of return of analysis results currently exceed 95%. More than 115,000 test samples have been sent worldwide by RTI to laboratories in these two programs. A review of more than 109,000 analysis results was undertaken to determine the frequencies of various qualitative error types, the types of bulk building materials most responsible for those errors, and the accuracy of precision of semiquantitative results. This assessment revealed that a small number of bulk building materials cause the majority of difficulties in each program, although error frequencies vary between the two programs. Overall laboratory performance has improved since the programs first began in the late 1980s, with a significant decline in qualitative errors and a much less dramatic decrease in errors associated with semiquantitative estimation of the amount of asbestos present.

• Asbestos exposures of mechanics performing clutch service on motor vehicles. H.J. Cohen, D.R. Van Orden. 2008;5(3):148-56. PubMed · Publisher

  Abstract

  A study was conducted to assess historical asbestos exposures of mechanics performing clutch service on motor vehicles. For most of the 20th century, friction components used in brakes and manual transmission clutches contained approximately 25-60% chrysotile asbestos. Since the late 1960s, asbestos exposure assessment studies conducted on mechanics performing brake service have frequently reported levels below the current OSHA permissible exposure limit (PEL) of 0.1 fiber/cc (flcc). Although there is a robust asbestos exposure data set for mechanics performing brake service, there are almost no data for mechanics removing and replacing clutches in manual transmission vehicles. Personal and area airborne asbestos samples were collected during the removal of asbestos-containing clutches from 15 manual transmissions obtained from salvage facilities by an experienced mechanic. Clutch plates and debris were analyzed for asbestos using EPA and ISO published analytical methods. More than 100 personal and area air samples were collected and analyzed for asbestos fibers using NIOSH methods 7400 and 7402. A separate study involved a telephone survey of 16 automotive mechanics who began work prior to 1975. The mechanics were asked about the duration, frequency, and methods used to perform clutch service. Wear debris in the bell housing surrounding clutches had an average of 0.1% chrysotile asbestos by weight, a value consistent with similar reports of brake debris. Asbestos air sampling data collected averaged 0.047 flcc. Mechanics participating in the telephone survey indicated that clutch service was performed infrequently, the entire clutch assembly was normally replaced, and there was no need to otherwise handle the asbestos-containing clutch plates. These mechanics also confirmed that wet methods were most frequently used to clean debris from the bell housing. Combining the asbestos exposure that occurred when mechanics performed clutch service, along with the duration and frequency of this task, the incremental contribution of this task to mechanics' 8-hr time-weighted average (TWA) asbestos exposures was 0.0016 flcc. Using the range of data inputs that were obtained, the authors calculated a range of TWA exposures of 3.75 x 10(-5) flcc to 0.03 flcc. The mean value of 0.0016 flcc is below background levels of asbestos that have been reported in garages during this time and below the current OSHA PEL of 0.1 flcc.

• Asbestos, pleural mesothelioma,and mortality in Italy. R.G. Carbone, B. Terracini, A. Marinaccio, et al. 2008;5(4):D55-6. Letter PubMed · Publisher

• Differentiating non-asbestiform amphibole and amphibole asbestos by size characteristics. M. Harper, E.G. Lee, S.S. Doorn, et al. 2008;5(12):761-70. PubMed · Publisher

  Abstract

  Mining or processing asbestos minerals can liberate isolated fibers or fiber bundles regulated as airborne asbestos fibers. Coarsely crystalline amphibole minerals are more common than asbestos in many geologic environments, and disturbance can result in the release of prismatic or acicular single crystals or cleavage fragments resembling asbestos fibers or fiber bundles but that are not currently regulated as asbestos. Bulk samples of six coarsely crystalline amphiboles and their five asbestos analogs were processed to maximize the number of particles meeting the criterion for counting under the current U.S. National Institute for Occupational Safety and Health Method 7400 "A" counting rules (> 5 microm long with an aspect ratio >or= 3:1) and also within the respirable width range, i.e. < 3 microm width. The length distributions of the particles produced showed substantial overlap between cleavage fragments and asbestos fibers. Available data sets generally confirmed the relevance of the size distributions of particles generated from reference materials to airborne particles. The length criterion in the current ASTM International standard D7200-06 causes a large proportion (e.g., 40% grunerite and 39% tremolite) of the non-asbestiform particles to be considered potential asbestos. An alternative procedure may be to use a distinction based on width alone as some, but not the majority of, cleavage fragments were thinner than 1 microm (e.g., 9% of actinolite and 20% of grunerite particles), and not many amphibole asbestos particles were wider (e.g., 5% of crocidolite and 18% of amosite particles). This proposal would need further testing. This research should not be considered as addressing any controversy with regard to the toxicity of non-asbestiform amphibole particles of similar dimensions to asbestos particles.

• Evaluation of public and worker exposure due to naturally occurring asbestos in gravel discovered during a road construction project. R.A. Perkins, J. Hargesheimer, L. Vaara. 2008;5(9):609-16. PubMed · Publisher

  Abstract

  During a repair and reconstruction project of an unpaved highway in a remote region of Alaska, workers discovered, after construction had commenced, that the materials used from a local material site contained asbestos (variously described as tremolite or actinolite). The regional geology indicated the presence of ultramafic rock, which often contains asbestos. Evaluation of asbestos exposure to workers, their equipment, and living quarters was required, as was the possible future exposure of workers and the general public to asbestos already used in the roadway construction. In addition, a decision was needed on whether to use materials from the contaminated site in the future. Of the almost 700 breathing zone air monitoring samples taken of the workers, 3% of the samples indicated exposures at or near 0.1 f/cc by the National Institute for Occupational Safety and Health (NIOSH) 7400 phase contrast microscopy (PCM) procedure. Thirty-six of the PCM samples underwent transmission electron microscopy (TEM) analysis by the NIOSH 7402 procedure, which indicated that about 40% of the fibers were asbestos. After classifying samples by tasks performed by workers, analysis indicated that workers, such as road grader operators who ground or spread materials, had the highest exposures. Also, monitoring results indicated motorist exposure to be much less than 0.1 f/cc. The design phase of any proposed construction project in regions that contain ultramafic rock must consider the possibility of amphibole contamination of roadway materials, and budget for exploration and asbestos analysis of likely materials sites.

• A new parameter to evaluate the quality of fiber count data of slides with relocatable fields. T. Pang. 2007;4(2):129-44. PubMed · Publisher

  Abstract

  Asbestos reference slides with relocatable fields are effective in determining the fiber counting errors and evaluating intercounter precision and accuracy. The process is time consuming and expensive as it requires (a) the analysts to record the number and the positions of the fibers and (b) an experienced microscopist to determine the errors. A new parameter based on the discrepancies between the reported fibers and the verified fibers is being investigated for monitoring the quality of fiber counts. The discrepancies are related to the fiber counting errors. The new process requires the analysts to report only the fibers in each field examined.

• Asbestos exposure during an abatement project. D.E. Welsh. 2007;4(2):D7-9. PubMed · Publisher

• Asbestos release from whole-building demolition of buildings with asbestos-containing material. R.A. Perkins, J. Hargesheimer, W. Fourie. 2007;4(12):889-94. PubMed · Publisher

  Abstract

  The whole-building demolition method, which entails one-or two-story buildings pushed down by heavy equipment, loaded into trucks, and hauled away, is generally the most cost-effective means to remove small buildings. For taller buildings, a crane and wrecking ball may be used initially to reduce the height of the building. Demolitions might release asbestos fibers from friable asbestos-containing material (ACM). Fibers also might be released from nominally nonfriable ACM (Categories I and II nonfriable ACM) if it becomes friable after rough handling throughout the whole-building demolition process. This paper reports on asbestos air monitoring from two demolition projects involving ACM. In one building, Category II nonfriable ACM was present because it could not be removed safely prior to demolition. Both projects had large quantities of gypsum wallboard with ACM joint compound and ACM flooring. One building had large quantities of ACM spray-on ceiling material. During the demolitions personal air monitoring of the workers and area air monitoring downwind and around the sites were conducted. The monitoring found the concentrations of fibers detected by phase contrast microscopy were generally well below the permissible exposure limits (PEL) of workers. Electron microcopy analysis of samples at or near the PEL indicated most of the fibers were not asbestos, and the actual asbestos exposure was often below the detection limit of the procedure. The buildings were kept wet with fire hoses during the demolition and that required large quantities of water, 20,000-60,000 gal/day (75-225 m(3)/day). Earlier studies found little asbestos release from buildings containing only nonfriable ACM demolished by this method. This project found a negligible release of asbestos fibers, despite the presence of nonfriable materials that might become friable, such as ACM joint compound and spray-on ACM ceiling coating.

• Heavy equipment maintenance exposure assessment: using a time-activity model to estimate surrogate values for replacement of missing data. F.W. Boelter, J.W. Spencer, C.E. Simmons. 2007;4(7):525-37. PubMed · Publisher

  Abstract

  This study on four pieces of heavy construction equipment was conducted to determine the concentration of airborne asbestos fibers during in-frame maintenance and repair activities, which included aggressive techniques that resulted in visible dust from work involving friction products and gaskets. Despite execution of a carefully planned sampling strategy, approximately 10% (47) of the samples collected could not be analyzed due to overloading or filter damage. To include the overloaded samples in the data analysis, surrogate values were estimated following a time-activity model. Twelve long-term personal samples, 2 short-term, 30-min personal samples, and 31 long-term area samples were modeled. Personal and area time-weighted average (TWA) data were analyzed both with and without the estimated surrogate values and compared. A total of 444 samples were collected over 9 days. Four experienced heavy equipment mechanics removed and replaced friction products and gaskets. Samples were analyzed using NIOSH Method 7400 Phase Contrast Microscopy followed by NIOSH Method 7402 Transmission Electron Microscopy. Sample data information including the surrogate values for the full-shift, TWA personal sample results ranged from 0.002 to 0.064 asbestos f/cc. Personal, short-term, 30-min sample results, including the two surrogate values, ranged from 0.038 to 0.561 asbestos f/cc. Full-shift TWA area samples, including the 31 surrogate values, ranged from 0.005 to 0.039 asbestos f/cc. Area air sample results at the end of the project were similar to levels measured before the start of the project. No fiber concentration buildup within the work area was indicated over the 9-day study. All full-shift personal and area TWA sample results were below 0.1 f/cc, and short-term 30-min personal samples were below 1.0 f/cc. Statistical results of the sample data with and without the surrogate values were consistent. Use of the time-activity model reduced the uncertainty associated with this data analysis and provided a consistent logical process for estimating surrogate values to replace missing data.

• Performance of membrane filters used for TEM analysis of asbestos. J.S. Webber, A.G. Czuhanich, L.J. Carhart. 2007;4(10):780-9. PubMed · Publisher

  Abstract

  This article presents findings related to characteristics of membrane filters that can affect the recovery of asbestos and the quality of preparations for transmission electron microscopy (TEM) analysis. Certain applications and preparation steps can lead to unacceptable performance of membrane filters used in analysis of asbestos by TEM. Unless substantial care is used in the collapsing of mixed-cellulose ester (MCE) filters with an acetone hot block, grid preparations can suffer and fiber recoveries can be compromised. Calibration of the etching depth of MCE filters, especially at differing locations in an asher's chamber, is critical for reliable fiber recovery. Excessive etching of MCE filters with aerosol-deposited asbestos can lead to loss of short fibers, while insufficient etching of MCE filters with aqueous-deposited asbestos can, paradoxically, also lead to loss of short fibers. Interlaboratory precision on MCE filters is improved by aerosol-deposited asbestos, as opposed to aqueous deposition. In comparison, straightforward preparation, improved solvents, and reduced contamination make PC filters an increasingly acceptable alternative. Variations in the geometric configuration during application of carbon films can lead to fiber loss and unacceptable grid quality for either type of filter.

• The effect of a proposed change to fiber-counting rules in ASTM International Standard D7200-06. M. Harper, E.G. Lee, B. Harvey, et al. 2007;4(5):D42-5. PubMed · Publisher

  Summary

  The authors examined how a proposed change to the fiber-classification rules in ASTM International Standard D7200-06 would affect the counting of amphibole cleavage fragments as potentially asbestiform fibers. Under the current standard, particles meeting the NIOSH 7400 "A" fiber definition (>5 μm long, aspect ratio ≥3:1) are assigned to Class 1 if curved or bundle-like, to Class 2 if >10 μm long or <1 μm wide, and otherwise to Class 3. The proposed alternative defines Class 2 as >10 μm long and <1 μm wide. The authors analyzed 77 air samples from a taconite mine ore-processing mill. Using the current criteria, 28% of fibers were Class 1 and 18.6% were Class 2. They also examined about 300 particles each from crushed nonasbestiform actinolite and tremolite, both identified by X-ray diffraction. Almost no particles were Class 1. Under the current and proposed Class 2 definitions, fibers in Class 2 were 25.1% and 0.6% for actinolite and 46.8% and 1.6% for tremolite. In the mine samples, Class 2 fell to about 0.8% under the proposed definition. A 3 μm width cut-off reduced Class 2 less in the mine samples, from 18.6% to 15.2%. The authors concluded that the current rules classify many cleavage fragments as potentially asbestiform, while the proposed change would place them almost entirely in Class 3. They noted that whether the change would also misclassify true asbestiform fibers had not been addressed. The data were described as provisional and not peer reviewed.

  PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

• A PC-based quality control (QC) program for an industrial hygiene laboratory. D.K. Verma, K. Ferguson, S.A. McCollin, et al. 2006;3(7):D56-66. PubMed · Publisher

• An exposure study of bystanders and workers during the installation and removal of asbestos gaskets and packing. C. Mangold, K. Clark, A. Madl, et al. 2006;3(2):87-98. PubMed · Publisher

  Abstract

  From 1982 until 1991, a series of studies was performed to evaluate the airborne concentration of chrysotile asbestos associated with replacing gaskets and packing materials. These studies were conducted by the senior author in response to concerns raised by a report from the Navy in 1978 on asbestos exposures associated with gasket work. A series of studies was conducted because results of those who worked with gaskets within the Navy study did not address the background concentrations of asbestos in the work areas, which may have been significant due to the presence of asbestos insulation in the ships and shipyards. The intent of the studies performed from 1982 through 1991 was to re-create the Navy's work practices in a contaminant-free environment during an 8-hour workday (so the data could be compared with the OSHA permissible exposure limit [PEL]). Samples were collected to characterize personal and area airborne asbestos concentrations associated with the formation, removal, and storage of gaskets, as well as the scraping of flanges and the replacement of valve packing. The results indicate that the 8-hour time-weighted average (TWA) exposures of pipefitters and other tradesmen who performed these activities were below the current PEL and all previous PELs. Specifically, the highest average 8-hour TWA concentration measured for workers manipulating asbestos gaskets during this study was 0.030 f/cc (during gasket removal and flange face scraping onboard a naval ship). Likewise, the 8-hour TWA breathing zone concentrations of a worker removing and replacing asbestos valve packing did not exceed 0.016 f/cc. In most cases, the concentrations were not distinguishable from ambient levels of asbestos in the ships or the general environment. These results are not surprising given that asbestos fibers in gasket materials are encapsulated within a binder.

• Evaluation of respirator filters for asbestos fibers. Y.S. Cheng, T.D. Holmes, B. Fan. 2006;3(1):26-35. PubMed · Publisher

  Abstract

  Fiber aerosols are known to have different aerodynamic behaviors than spherical particles and usually carry higher electrostatic charges. We investigated the effects of flow rate and charge status of filter cartridges on the penetration of spherical and fiber aerosols. Four types of test respirator filters were selected: two for passive respirators, one for a powered respirator, and one disposable respirator. Surface charges on respirator filters were determined using a noncontact field electrostatic field meter. Penetration tests were performed for filter cartridges before and after charge neutralization. The surface charge measurements on the respirator filters showed that some filters, including those used in disposable face masks, are charged to enhance the collection efficiency. Only high-efficiency particulate air filters performed consistently for both spherical test aerosols and the three types of asbestos fibers. The surface charge potential of filter cartridges and flow rate did not appear to affect the performance of these filters. In contrast to the high-efficiency filters, the aerosol penetration performance of low-efficiency filters and face masks deteriorated when the charge potential on the filter was removed. Our data also showed that the surface charges decreased in a high-temperature, high-humidity environment and disappeared after 1 week. Deposition of spherical particles and fibers in the charged disposable facemask filter was enhanced. For charged-neutralized, low-efficiency filter cartridges, asbestos fibers may penetrate more than spherical particles with a mean particle size of 0.3 microm diameter.

• Asbestos exposures to truck drivers during World Trade Center cleanup operations. P.N. Breysse, D.L. Williams, J.B. Herbstman, et al. 2005;2(8):400-5. PubMed · Publisher

  Abstract

  This article presents results of asbestos air sampling conducted to assess the exposure to truck drivers working at the World Trade Center site. Sampling consisted of a combination of area and personal monitoring of 49 truck drivers and included optical and electron microscopic analyses. Three sampling periods were conducted: October 1-7, 2001, October 17-26, 2001, and April 13-23, 2002. Area sample locations were selected to estimate airborne concentrations around the perimeter of the site, on top of the pile, and in the pit. Air samples were collected using a 50-mm conductive cowl and a 25-mm mixed cellulose ester filter at flow rates ranging from 0.5-2 L/min. Samples were analyzed using a combination of phase contrast microscopy (PCM) NIOSH method 7400, transmission electron microscopy (TEM) NIOSH method 7402, and the direct method specified under the Asbestos Hazardous Emergency Response Act. Sample times and flow rates were adjusted to prevent overloading while maximizing sample volume. Personal sampling results suggest that asbestos fiber exposures to truck drivers at the site were low. Exposures based on TEM results generally ranged from less than detectable to 0.1 structures per cubic centimeter (s/cm(3)). TEM-based results further indicate that the majority of asbestos fibers were chrysotile and less than 5 microm in length. PCM-based estimates were generally higher than the TEM results. This is likely due to the counting of nonasbestos fibers. This conclusion is supported by the NIOSH 7402 TEM results, which did not detect asbestos fibers longer than 5 micro m. Area sample results were generally less than the personal results (except for the sample collected on top of the rubble pile) and decreased over the course of the cleanup. Our results show low airborne asbestos concentrations and a predominance of short fibers. Given these low concentrations, evidence of short fibers, and the short duration of the exposure (less than 10 months to complete the cleanup), it is likely that truck drivers working at the site are not at an increased risk for asbestos-related disease.

• Assessing truck driver exposure at the World Trade Center disaster site: personal and area monitoring for particulate matter and volatile organic compounds during October 2001 and April 2002. A.S. Geyh, S. Chillrud, D.L. Williams, et al. 2005;2(3):179-93. PubMed · Publisher

  Abstract

  The destruction of the World Trade Center (WTC) in New York City on September 11, 2001, created a 16-acre debris field composed of pulverized and burning material significantly impacting air quality. Site cleanup began almost immediately. Cleanup workers were potentially exposed to airborne contaminants, including particulate matter, volatile organic compounds, and asbestos, at elevated concentrations. This article presents the results of the exposure assessment of one important group of WTC workers, truck drivers, as well as area monitoring that was conducted directly on site during October 2001 and April 2002. In cooperation with a local labor union, 54 drivers (October) and 15 drivers (April) were recruited on site to wear two monitors during their 12-hour work shifts. In addition, drivers were administered a questionnaire asking for information ranging from "first day at the site" to respirator use. Area monitoring was conducted at four perimeter locations during October and three perimeter locations during April. During both months, monitoring was also conducted at one location in the middle of the rubble. Contaminants monitored for included total dust (TD), PM10, PM2.5, and volatile organic compounds. Particle samples were analyzed for mass, as well as elemental and organic carbon content. During October, the median personal exposure to TD was 346 microg/m3. The maximum area concentration, 1742 microg/m3, was found in middle of the debris. The maximum TD concentration found at the perimeter was 392 microg/m3 implying a strong concentration gradient from the middle of debris outward. PM2.5/PM10 ratios ranged from 23% to 100% suggesting significant fire activity during some of the sampled shifts. During April, the median personal exposure to TD was 144 microg/m3, and the highest area concentration, 195 microg/m3, was found at the perimeter. During both months, volatile organic compounds concentrations were low.

• Occupational exposure to airborne asbestos from phenolic molding material (Bakelite) during sanding, drilling, and related activities. F. Mowat, M. Bono, R.J. Lee, et al. 2005;2(10):497-507. PubMed · Publisher

  Abstract

  In this study, a historical phenolic (Bakelite) molding material, BMMA-5353, was tested to determine the airborne concentrations of asbestos fibers released during four different activities (sawing, sanding, drilling, and cleanup of dust generated from these activities). Each activity was performed for 30 min, often in triplicate. The primary objective for testing BMMA-5353 was to quantitatively determine the airborne concentration of asbestos fibers, if any, in the breathing zone of workers. Uses of this product typically did not include sawing or sanding, but it may have been drilled occasionally. For this reason, only small quantities were sawed, sanded, and drilled in this simulation study. Personal (n = 40), area (n = 80), and background/clearance (n = 88) air samples were collected during each activity and analyzed for total fiber concentrations using phase contrast microscopy (PCM) and, for asbestos fiber counts, transmission electron microscopy (TEM). The raw PCM-total fiber concentrations were adjusted based on TEM analyses that reported the fraction of asbestos fibers, to derive a PCM-asbestos concentration that would enable calculation of an 8-hour time-weighted average (TWA). The estimated 8-hour TWAs ranged from 0.006 to 0.08 fibers per cubic centimeter using a variety of worker exposure scenarios. Therefore, assuming an exposure scenario in which a worker uses power tools to cut and sand products molded from BMMA-5353 and similar products in the manner evaluated in this study, airborne asbestos concentrations should not exceed current or historical occupational exposure limits.

• Airborne asbestos levels in school buildings in Italy. A. Campopiano, S. Casciardi, F. Fioravanti, et al. 2004;1(4):256-61. PubMed · Publisher

  Abstract

  This article provides a summary of environmental investigations carried out from 1992 to 2002 by the National Institute for Occupational Prevention and Safety on airborne asbestos fiber concentrations in Italian schools. The monitoring was performed to evaluate the risk from asbestos exposure to students and school staff. Fifty-nine schools located in several Italian regions were studied. A detailed visual examination assisted with locating asbestos-containing materials in different school areas. Asbestos was mainly present in the vinyl floor coverings and in the asbestos-cement products (roofs, facades, and heating ducts). After the identification of the potential sources of exposure, several bulk and air samplings were performed in the areas where the contamination was suspected. All air samplings were collected on membrane filters and analyzed by phase contrast optical microscopy and scanning electron microscopy. During the course of the samplings, the schools were in operation and normal student activities took place. Most of the results provided no significant evidence of airborne asbestos fibers, although some dispersion was found in a few school buildings where, during the past years, monitoring and safety programs had not been implemented.

• Occupational exposures during routine activities in coal-fueled power plants. M.J. Bird, D.L. MacIntosh, P.L. Williams. 2004;1(6):403-13. PubMed · Publisher

  Abstract

  Limited information is available on occupational exposures during routine, nonoutage work activities in coal-fueled power plants. This study evaluated occupational exposures to the principal contaminants in the facilities, including respirable dust (coal dust), arsenic, noise, asbestos, and heat stress. The data were collected over a 3-month period, during the summer of 2001, in 5 facilities that were chosen to be representative of the coal-fueled power plants of a large southeastern power-generating company. Each of the facilities was divided into 5 similar exposure groups based on previous exposure assessments and job tasks performed. From 4 of the 5 facilities, 392 air samples and 302 noise samples were collected with approximately 50 respirable coal dust, 32 arsenic, 15 asbestos, and 70 noise samples from each of the 4 plants. One of the previously surveyed facilities was also evaluated for heat stress, and 1 additional coal-fueled power plant was surveyed for a total of 20 personal heat stress samples. Personal monitors and area WBGT monitors were used. Of the nearly 400 air samples collected, only 1 exceeded the allowable occupational exposure value. For the noise samples, 55 (approximately 18%) were equal to or greater than the Occupational Safety and Health Administration (OSHA) 8-hour hearing conservation program level of 85 dBA, and 12 (approximately 4%) were equal to or greater than the OSHA 8-hour permissible exposure level of 90 dBA. Heat stress monitoring at the facilities indicates that 26% of the 1-hour TWAs were exceeded for one or all of the recommended heat stress limits. The data also concluded that some work sites were above the heat stress ceiling values recommended by the National Institute for Occupational Safety and Health (NIOSH). Four of the 20 employees personally monitored exceeded the recommended limits for heart rate or body core temperature. This suggests there is a potential for heat strain if signs and symptoms are ignored. Recommendations are made to better control the heat stress exposure.

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