Asbestos Exposure Surveillance 

Compiled by Joe Ladou




The Agency for Toxic Substances & Disease Registry provides general information and links to more specific guides. Significant exposure to any type of asbestos will increase the risk of lung cancer, mesothelioma and nonmalignant lung and pleural disorders, including asbestosis, pleural plaques, pleural thickening, and pleural effusions. This conclusion is based on observations of these diseases in groups of workers with cumulative exposures ranging from about 5 to 1,200 fiber-year/mL. Such exposures would result from 40 years of occupational exposure to air concentrations of 0.125 to 30 fiber/mL. See Detecting Asbestos, for typical levels of concentration. The conclusion is supported by results from animal and mechanistic studies.

The American Industrial Hygiene Association does not endorse or recommend any specific NIOSH 582 equivalency course. However, since the National Institute for Occupational Safety and Health (NIOSH) discontinued its offering of the NIOSH 582 course for Sampling and Evaluating Airborne Asbestos Dust, it has become increasingly difficult to find the equivalency course that is necessary for PCM analysts to comply with OSHA regulations.

The Asbestos Analyst Registry (AAR) program, offered by the American Industrial Hygiene Association's (AIHA) Laboratory Quality Assurance Programs (LQAP), was designed to recognize the analysts of organizations involved in asbestos fiber counting on air samples outside of established laboratory locations, primarily on the job site or in the field.All registered analyst must be associated with an AAR-Approved organization that oversees the Quality Assurance and Quality Control program that monitors the analyst.The program requires documented NIOSH 582 training, adherence to the quality assurance and quality control requirements set forth by  OSHA in 29 CFR 1910.1001 Appendix A and the most current version of the NIOSH 7400 Method, and ongoing proficient performance in the Asbestos Analytical Testing (AAT) program by all registered analysts.


Park D, Choi S, Ryu K, Park J, Paik N. Trends in occupational asbestos exposure and asbestos consumption over recent decades in Korea. Int J Occup Environ Health. 2008 Jan-Mar;14(1):18-24. Department of Environmental Health, Korea National Open University, Seoul, Korea.

In Korea, national statistics for asbestos exposure levels covering various asbestos industries and associated with specific years have never been published. The authors analyzed 2,089 asbestos exposure data sets compiled from 1995 through 2006. Exposure levels were characterized according to type of asbestos industry and year. Asbestos exposure levels have decreased over time, dropping sharply from 0.92 fibers/cc (f/cc) in 1996 to 0.60 f/cc in 1997, to 0.19 f/cc in 1998, and to 0.06 f/cc in 1999, possibly in part because of enforcement of 1997 legislation banning the use of amosite and crocidolite. In particular, a substantial reduction in asbestos exposure levels was most evident among primary industries handling raw asbestos directly. A similar relationship was found between a significant decline in asbestos consumption volume and the timing of regulation enforcement.

Chapman A, Mulrennan S, Ladd B, Muers MF. Population-based epidemiology and prognosis of mesothelioma in Leeds, United Kingdom. Thorax. 2008 Jan 17. Northalleton Hospital, United Kingdom.

INTRODUCTION: Malignant mesothelioma is a fatal neoplasm, which is rapidly increasing in incidence throughout Western Europe. To date there have been no studies reporting upon the natural history and interventional practices on a comprehensive unselected population, as opposed to reports from referral institutions or compensation claimants. We present a population based study capturing data on all patients with mesothelioma presenting within a defined geographical area over a 4 year period in the UK. Method: Data of all cases occurring in Leeds with a population of 750,000 were collected retrospectively from 2002 to 2003 and prospectively from 2004 through 2005. All patients' hospital records and the trust histology database were reviewed, as well as coroner's reports on all patients with a post mortem diagnosis of mesothelioma. RESULTS: Over the 4 year study period there was a total of 146 cases in Leeds. 77% were male. Median age was 74 (range 36-93). Median survival from diagnosis was 8.9 months. 92% and 8% had a histological or a cytological confirmation respectively. 85% had documented evidence of definite or probable exposure to asbestos. 110/146 (75%) had symptomatic pleural effusions at presentation. Twice the number of patients (42 vs 17) were managed with surgical rather than bedside pleurodesis and these had a lower recurrence rate (14% vs 47%) p=0.02. 122 patients had VATS/cutting CT biopsies or chest drains. 73/122 (60%) had prophylactic radiotherapy to these sites. There were 7 cases (5%) of tract invasion by tumour and 6 of these had received prophylactic radiotherapy. Median time to seeding was 174 days. 92/146 (63%) had a performance status of 2 or better at diagnosis but only 54/146 were considered fit for chemotherapy. Of these 28 (52%) declined chemotherapy; the overall uptake of chemotherapy or entry into a trial was 18%. No patient had radical surgery. CONCLUSION: This comprehensive population based audit has shown that the median age at presentation of malignant mesothelioma is increasing and baseline performance status and survival is worse than in selected series. 37% of patients were considered suitable for palliative chemotherapy but less than 20% accepted this offer. Thorascopic pleurodesis appears to be associated with fewer recurrences. The role of prophylactic radiotherapy to chest drain and biopsy sites needs re-appraisal.

Pierce JS, McKinley MA, Paustenbach DJ, Finley BL. An evaluation of reported no-effect chrysotile asbestos exposures for lung cancer and mesothelioma. Crit Rev Toxicol. 2008;38(3):191-214. ChemRisk, Inc., San Francisco, California, USA.

Numerous investigators have suggested that there is likely to be a cumulative chrysotile exposure below which there is negligible risk of asbestos-related diseases. However, to date, little research has been conducted to identify an actual "no-effect" exposure level for chrysotile-related lung cancer and mesothelioma. The purpose of this analysis is to summarize and present all of the cumulative exposure-response data reported for predominantly chrysotile-exposed cohorts in the published literature. Criteria for consideration in this analysis included stratification of relative risk or mortality ratio estimates by cumulative chrysotile exposure. Over 350 studies were initially evaluated and subsequently excluded from the analysis due primarily to lack of cumulative exposure information, lack of information on fiber type, and/or evidence of significant exposures to amphiboles. Fourteen studies meeting the inclusion criteria were found where lung cancer risk was stratified by cumulative chrysotile exposure; four such studies were found for mesothelioma. All of the studies involved cohorts exposed to high levels of chrysotile in mining or manufacturing settings. The preponderance of the cumulative "no-effects" exposure levels for lung cancer and mesothelioma fall in a range of approximately 25-1000 fibers per cubic centimeter per year (f/cc-yr) and 15-500 f/cc-yr, respectively, and a majority of the studies did not report an increased risk at the highest estimated exposure. Sources of uncertainty in these values include errors in the cumulative exposure estimates, conversion of dust counts to fiber data, and use of national age-adjusted mortality rates. Numerous potential biases also exist. For example, smoking was rarely controlled for and amphibole exposure did in fact occur in a majority of the studies, which would bias many of the reported "no-effect" exposure levels towards lower values. However, many of the studies likely lack sufficient power (e.g., due to small cohort size) to assess whether there could have been a significant increase in risk at the reported no-observed-adverse-effects level (NOAEL); additional statistical analyses are required to address this source of bias and the attendant influence on these values. The chrysotile NOAELs appear to be consistent with exposure-response information for certain cohorts with well-established industrial hygiene and epidemiology data. Specifically, the range of chrysotile NOAELs were found to be consistently higher than upper-bound cumulative chrysotile exposure estimates that have been published for pre-1980s automobile mechanics (e.g., 95th percentile of 2.0 f/ cc-yr), an occupation that historically worked with chrysotile-containing friction products yet has been shown to have no increased risk of asbestos-related diseases. While the debate regarding chrysotile as a risk factor for mesothelioma will likely continue for some time, future research into nonlinear, threshold cancer risk models for chrysotile-related respiratory diseases appears to be warranted.

Welch LS. Asbestos exposure causes mesothelioma, but not this asbestos exposure: an amicus brief to the Michigan Supreme Court. Int J Occup Environ Health. 2007 Jul-Sep;13(3):318-27. Center to Protect Workers Rights, 8484 Georgia Avenue, Silver Spring, MD 20910, USA.

Manufacturers of asbestos brakes, supported by many manufacturing and insurance industry amicus curie, requested the Michigan Supreme Court to dismiss testimony of an expert regarding the ability of asbestos dust from brakes to cause mesothelioma as "junk science". Scientists are concerned with the sweeping and unequivocal claims that any conclusion that asbestos from brakes caused a signature asbestos-related disease in a particular person must be "junk science". The manufacturers' sweeping pronouncements are what veer from accepted, reliable mainstream scientific methods and conclusions. This article outlines the evidence supporting the conclusion that asbestos from brakes can and does cause mesothelioma, and describes the defendants' attempts to fabricate doubt about this conclusion.

Williams PR, Phelka AD, Paustenbach DJ. A review of historical exposures to asbestos among skilled craftsmen (1940-2006). J Toxicol Environ Health B Crit Rev. 2007 Sep-Oct;10(5):319-77. ChemRisk, Boulder, Colorado 80301, USA.

This article provides a review and synthesis of the published and selected unpublished literature on historical asbestos exposures among skilled craftsmen in various nonshipyard and shipyard settings. The specific crafts evaluated were insulators, pipefitters, boilermakers, masons, welders, sheet-metal workers, millwrights, electricians, carpenters, painters, laborers, maintenance workers, and abatement workers. Over 50 documents were identified and summarized. Sufficient information was available to quantitatively characterize historical asbestos exposures for the most highly exposed workers (insulators), even though data were lacking for some job tasks or time periods. Average airborne fiber concentrations collected for the duration of the task and/or the entire work shift were found to range from about 2 to 10 fibers per cubic centimeter (cm3 or cc) during activities performed by insulators in various nonshipyard settings from the late 1960s and early 1970s. Higher exposure levels were observed for this craft during the 1940s to 1950s, when dust counts were converted from millions of particles per cubic foot (mppcf) to units of fibers per cubic centimeter (fibers/cc) using a 1:6 conversion factor. Similar tasks performed in U.S. shipyards yielded average fiber concentrations about two-fold greater, likely due to inadequate ventilation and confined work environments; however, excessively high exposure levels were reported in some British Naval shipyards due to the spraying of asbestos. Improved industrial hygiene practices initiated in the early to mid-1970s were found to reduce average fiber concentrations for insulator tasks approximately two- to five-fold. For most other crafts, average fiber concentrations were found to typically range from <0.01 to 1 fibers/cc (depending on the task or time period), with higher concentrations observed during the use of powered tools, the mixing or sanding of drywall cement, and the cleanup of asbestos insulation or lagging materials. The available evidence suggests that although many historical measurements exceeded the current OSHA 8-h time-weighted average (TWA) permissible exposure limit (PEL) of 0.1 fibers/cc, average fiber concentrations generally did not exceed historical occupational exposure limits in place at the time, except perhaps during ripout activities or the spraying of asbestos in enclosed spaces or onboard ships. Additionally, reported fiber concentrations may not have represented daily or actual human exposures to asbestos, since few samples were collected beyond specific short-term tasks and workers sometimes wore respiratory protective equipment. The available data were not sufficient to determine whether the airborne fiber concentrations represented serpentine or amphibole asbestos fibers, which would have a pronounced impact on the potential health hazards posed by the asbestos. Despite a number of limitations associated with the available air sampling data, the information should provide guidance for reconstructing asbestos exposures for different crafts in specific occupational settings where asbestos was present during the 1940 to 2006 time period.

Larson T, Melnikova N, Davis SI, Jamison P. Incidence and descriptive epidemiology of mesothelioma in the United States, 1999-2002. Int J Occup Environ Health. 2007 Oct-Dec;13(4):398-403. Division of Health Studies, Agency for Toxic Substances and Disease Registry, Atlanta, GA 30333, USA.

To estimate the recent incidence of mesothelioma in the United States and characterize its descriptive epidemiology, incidence data were obtained from the National Program of Cancer Registries (NPCR) and the Surveillance, Epidemiology and End Results (SEER) Program. Age-adjusted incidence rates and 95% confidence intervals were calculated. The U.S. incidence was 1.11 cases per 100,000 persons. Most cases occurred among older, white males. However, 173 cases (< 2%) occurred in persons younger than 40. The proportion of women with peritoneal mesothelioma was triple that of men (14.8% vs 5.4%). Of 40 reporting states, 11 had incidence rates significantly higher than the national rate.

Pelclov\'e1 D, Fenclov\'e1 Z, Urban P. Asbestos exposure, legislation and diseases in the Czech Republic. Cent Eur J Public Health. 2007 Sep;15(3):99-102. Department of Occupational Medicine, Charles University, Prague.

Asbestos manufacturing has been banned in the Czech Republic; however, about 280 workers in the 2nd-4th work category have been exposed during the remediation of asbestos, and the health consequences of the former use of asbestos will be apparent for many years. The incidence of mesothelioma in the Czech Republic is about 0.5/100,000 inhabitants, which places it among the lowest incidences of mesothelioma in Europe, and ranks the Czech Republic among the countries with the lowest rates in the world. The proportion of occupational mesotheliomas is only about one-tenth of these malignancies. These data show an underreporting of occupational cancers, most probably due to low awareness of the association of exposures more than 40 years ago with this disease. Physicians should focus more on the occupational history of these patients and refer them to the Departments of occupational diseases. Benefits are available for all patients with mesothelioma, in whom industrial hygienists confirm former exposure to asbestos, corresponding to the latency period.

Fasola G, Belvedere O, Aita M, Zanin T, Follador A, Cassetti P, Meduri S, De Pangher V, Pignata G, Rosolen V, Barbone F, Grossi F. Low-dose computed tomography screening for lung cancer and pleural mesothelioma in an asbestos-exposed population: baseline results of a prospective, nonrandomized feasibility trial--an Alpe-adria Thoracic Oncology Multidisciplinary Group Study (ATOM 002). Oncologist. 2007 Oct;12(10):1215-24. Department of Medical Oncology, University Hospital of Udine, P.le S. M. Misericordia 15, 33100 Udine, Italy.

OBJECTIVE: To evaluate the feasibility of using low-dose computed tomography (LDCT) for the early diagnosis of lung cancer and malignant pleural mesothelioma in an asbestos-exposed population. METHODS: Between February 2002 and October 2003, 1,045 volunteers already enrolled in a surveillance program for asbestos-exposed workers and former workers were recruited. The main eligibility criteria were: written informed consent, definite exposure to asbestos, age 40-75, no prior cancer or severe concomitant conditions, no chest CT scan in the past 2 years. A smoking history was not required. After a structured interview, chest X-ray (CXR) and LDCT were performed. Participants with negative examinations were assigned to annual LDCT. Participants with positive findings received high-resolution CT and additional diagnostic workup as appropriate. RESULTS: Baseline characteristics of the screened population were: median asbestos exposure time, 30 years; median age, 58; median pack-years in smokers/former smokers, 18.5. Thirty-four percent had never smoked. On LDCT, 834 noncalcified nodules were identified in 44% of participants, versus 43 nodules in 4% on CXR. Pleural abnormalities were observed in 44% and 70% of participants by CXR and LDCT, respectively. Overall, LDCT identified nine cases of non-small cell lung cancer-eight stage I, one stage IIA-and one thymic carcinoid, corresponding to 1% of the enrolled population. All cases were radically treated. None had been detected by CXR. No pleural mesothelioma was diagnosed. There were 11 false-positive results. CONCLUSIONS: Our findings first suggest that LDCT may be at least as useful in asbestos workers as in heavy smokers for the early diagnosis of lung cancer; this benefit is evident even in a poor-risk population, with low rates of smoking prevalence and a previous history of radiological surveillance. The role of spiral tomography in screening for pleural mesothelioma remains uncertain.

Barbieri PG, Somigliana A, Caironi M, Migliori M. The epidemiologic surveillance of malignant mesothelioma in the Lower Iseo Lake area [Article in Italian]. Epidemiol Prev. 2007 Jul-Aug;31(4 Suppl 1):16-22. Unità operativa Medicina del lavoro, Servizio prevenzione e sicurezza ambienti di lavoro, ASL Brescia.

Starting from an hospital observation of the mesotheliomas cluster in women living in a lakeside area (Iseo lake, Northern Italy), an epidemiological surveillance of this tumour was performed by the local occupational health service. This cluster wasn't notified, in spite of the relevant number of factories producing asbestos textile materials in this area. From 1977 to august 2006, 45 cases of mesothelioma were detected among the workers of 3 textile industries located in 3 little villages: 14 cases occurred working crocidolite and chrysotile rope and gasket; 20 cases in a textile factory producing cotton garments, that was adjacent to and polluted by the farmer and were asbestos insulation and blankets used for fireproofing are present; 11 cases occurred among women working in silk factories. The mesothelioma cases occurred in the same period in this area, which constituted the recruitment area of the people working in the 3 textile plants (11 villages, about 43,000 inhabitants), are 55.93% of which had been occupationally exposed to asbestos. Out of the dockyard and the asbestos-cement industries, this frequency of occupational exposed workers is the highest never observed in Italy. The majority of the cases (66%) occurred among women working in the textile factories. In a women, producing asbestos textile materials and suffered form peritoneal mesothelioma and pleural plaques, the analysis (by SEM) of asbestos fibre lung burden show 286 million fibres x gr. of dry tissue. Between the 42 mesothelioma cases occurring in the population of the 3 villages where the textile plants was located, we observed only one case with possible environmental exposure to asbestos: a gardener of the village where the manufacturing asbestos ropes and gasket plant is present. In the silk factories, asbestos exposure was probable because of the presence of asbestos insulated pipes. The female pleural mesothelioma standard incidence observed in this area (6.8 x 100,000, 1977-2005) is the highest never estimate in Italy. The epidemiological surveillance of the mesothelioma appear essential to identify cases unreported and allow the collection of information useful to understand clearly the asbestos exposure effects on health's workers and to estimate the tumour incidence in the population.

Marinaccio A, Binazzi A, Cauzillo G, Chellini E, De Zotti R, Gennaro V, Menegozzo M, Mensi C, Merler E, Mirabelli D, Musti M, Pannelli F, Romanelli A, Scarselli A, Tosi S, Tumino R, Nesti M; Gruppo di lavoro ReNaM. Epidemiological surveillance of malignant mesothelioma cases in Italy: incidence and asbestos exposure figures by the Italian mesothelioma registry (ReNaM) [Article in Italian]. Epidemiol Prev. 2007 Jul-Aug;31(4 Suppl 1):23-6. ISPESL, Dipartimento di medicina del lavoro, Laboratorio di epidemiologia, Roma.

The Study describes the epidemiological surveillance of mesothelioma cases carried out by the Italian mesothelioma register (ReNaM). A Regional Operating Centre (COR) is present in nearly all Italian regions (17 out of 20) and it collects malignant mesothelioma cases and investigate the modalities of asbestos exposure by using a structured questionnaire. The register produces malignant mesothelioma incidence measures and analyses of the modalities of the asbestos exposure. The standardized incidence rate of malignant mesothelioma in 2001 was 2.98 (in 100,000 inhabitants) among men and 0.98 among women; a professional (certain, probable, possible) exposure has been detected in 67.4% of defined cases. In addition to the conventional sectors (shipbuilding, railways repair and demolition, asbestos-cement production), also textile, building, transport, chemical and glass industries, petroleum and sugar refineries, electricity production and distribution plants are getting involved. Despite the absence of some regions completing the national coverage and the non homogeneity in collecting and coding data, the epidemiological surveillance of malignant mesothelioma carried out by ReNaM is an important tool for the scientific knowledge and the prevention of asbestos-related diseases.

Bridda A, Padoan I, Mencarelli R, Frego M. Peritoneal mesothelioma: a review. MedGenMed. 2007 May 10;9(2):32. Clinica Chirurgica I, Department of Surgical and Gastroenterological Sciences, University of Padua, School of Medicine, Via Giustiniani 2, Policlinico III Piano, 35128 Padova, Italy.

BACKGROUND: Malignant peritoneal mesothelioma (MPM) is a rare aggressive tumor of the peritoneum, regarded as a universally fatal disease. It is poorly described and the knowledge of its natural history is very limited. Occupational and environmental asbestos exposure still remains a public health problem around the world. The incidence has increased in the past 2 decades. Only 20% to 33% of all mesotheliomas arise from the peritoneum itself; the pleura is the most common site of origin.

Mensi C, Macchione M, Termine L, Canti Z, Rivolta G, Riboldi L, Chiappino G. Asbestos exposure in the non-asbestos textile industry: the experience of the Lombardy Mesothelioma Registry [Article in Italian]. Epidemiol Prev. 2007 Jul-Aug;31(4 Suppl 1):27-30. Dipartimento di medicina preventiva, ambientale e del lavoro, Fondazione IRCCS-Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena.

The Lombardy Mesothelioma Registry, activated in 2000, receives more than 300 cases per year of suspected malignant mesothelioma; the standardized (age and gender) incidence rate of pleural mesothelioma is 2.4/100,000 inhabitants (CI 95% 2.0-2.7). The finding of an increasing number of cases among workers of the non-asbestos-textile industry, classified as "unknown exposure to asbestos", upheld the suspect of presence of asbestos in this compartment. Specific information about a possible asbestos exposure were collected by technicians, maintenance personnel and other experts; industrial machinery utilized in the past was thoroughly examined; direct inspections were carried out in several workplaces that had not yet undergone significant changes with respect to the past. A large amount of asbestos had been regularly used on the ceilings and also to the walls of factories in order to avoid both condensation of steam and reflection of noise. In addition, asbestos had also been widely used to insulate water and steam pipes. The braking systems of most of machines also had asbestos gaskets, and on several looms some brakes operated continuously. The population in study was composed of 119 subjects, 27 males and 92 females, median age of 72 years. Asbestos exposure was ascribed to work in 106 cases (89%). The system devised by the Lombardy Registry had brought to light an occupational hazard in a professional area previously never believed as a source of asbestos exposure. In consideration of the described experience, both environmental and clinical, it seems reasonable to consider the non-asbestos-textile as a new department at risk for asbestos exposure.

Wilson R, McConnell EE, Ross M, Axten CW, Nolan RP. Risk assessment due to environmental exposures to fibrous particulates associated with taconite ore. Regul Toxicol Pharmacol. 2007 Nov 28. Department of Physics and the Center for Risk Assessment, 9 Oxford Street Rear, Harvard University, Cambridge, MA 02138, USA.

In the early 1970s, it became a concern that exposure to the mineral fibers associated taconite ore processed in Silver Bay, Minnesota would cause asbestos-related disease including gastrointestinal cancer. At that time data gaps existed which have now been significantly reduced by further research. To further our understanding of the types of airborne fibers in Silver Bay we undertook a geological survey of their source the Peter Mitchell Pit, and found that there are no primary asbestos minerals at a detectable level. However we identified two non-asbestos types of fibrous minerals in very limited geological locales. Air sampling useful for risk assessment was done to determine the type, concentrations and size distribution of the population of airborne fibers around Silver Bay. Approximately 80% of the airborne fibers have elemental compositions consistent with cummingtonite-grunerite and the remaining 20% have elemental compositions in the tremolite-actinolite series. The mean airborne concentration of both fiber types is less than 0.00014 fibers per milliliter that is within the background level reported by the World Health Organization. We calculate the risk of asbestos-related mesothelioma and lung cancer using a variety of different pessimistic assumptions. (i) that all the non-asbestos fibers are as potent as asbestos fibers used in the EPA-IRIS listing for asbestos; with a calculated risk of asbestos-related cancer for environmental exposure at Silver Bay of 1 excess cancer in 28,500 lifetimes (or 35 excess cancers per 1,000,000 lifetimes) and secondly that taconite associated fibers are as potent as chrysotile the least potent form of asbestos. The calculated risk is less than 0.77 excess cancer case in 1,000,000 lifetimes. Finally, we briefly review the epidemiology studies of grunerite asbestos (amosite) focusing on the exposure conditions associated with increased risk of human mesothelioma.

Porret E, Madelaine J, Galateau-Sall\'e9 F, Bergot E, Zalcman G. Epidemiology, molecular biology, diagnostic and therapeutic strategy of malignant pleural mesothelioma in 2007 - an update [Article in French]. Rev Mal Respir. 2007 Oct;24(8 Pt 2):6S157-64. Service de Pneumologie, Ple Coeur-Poumons-Vaisseaux, Université Basse-Normandie, CHU de Caen, France.

Malignant pleural mesothelioma (MPM) is a rare tumour due to occupational asbestos exposure. The incidence of MPM will continue to increase until 2020-2030. The incidence reaches 100 cases/million/year in occupationally exposed populations as opposed to 1 case/million/year in the general population, leading to 800 to 1,000 cases per year in France. The molecular carcinogenesis of MPM is incompletely understood but alterations to genes NF2, c-met, WT1 RASSF and p16 have been described. These genes are involved in cell invasion and motility, cell division and apoptosis control. Histological diagnosis remains difficult and depends on immunohistochemical analysis as described by the French Mesopath group. Clinical diagnosis relies on thoracoscopy and large pleural biopsies, with increasing use of CT-PET for the evaluation of disease extent. Therapeutic strategy includes prophylactic irradiation following drainage or thoracoscopy to prevent tumour nodule development along drainage channels and puncture sites. In selected patients, extensive extra-pleural pneumonectomy can be performed with curative intent. First line chemotherapy is based on a combination of pemetrexed and cisplatin that has demonstrated an improvement in overall survival and quality of life in phase 3 trials. Antiangiogenic agents such as bevacizumab (Avastatin) may be of interest but need to be tested in phase 3 trials. The Mesothelioma Avastatin Pemetrexed Study (MAPS) is ongoing, coordinated by the French Thoracic Cancer Intergroup (IFCT).

Williams P, Paustenbach D, Balzer JL, Mangold C. Retrospective exposure assessment of airborne asbestos related to skilled craftsmen at a petroleum refinery in Beaumont, Texas (1940-2006). J Toxicol Environ Health A. 2007 Jul;70(13):1076-107. ChemRisk Boulder, Colorado 80301, USA.

Despite efforts over the past 50 or more years to estimate airborne dust or fiber concentrations for specific job tasks within different industries, there have been no known attempts to reconstruct historical asbestos exposures for the many types of trades employed in various nonmanufacturing settings. In this paper, 8-h time-weighted average (TWA) asbestos exposures were estimated for 12 different crafts from the 1940s to the present day at a large petroleum refinery in Beaumont, TX. The crafts evaluated were insulators, pipefitters, boilermakers, masons, welders, sheet-metal workers, millwrights, electricians, carpenters, painters, laborers, and maintenance workers. This analysis quantitatively accounts for (1) the historical use of asbestos-containing materials at the refinery, (2) the typical workday of the different crafts and specific opportunities for exposure to asbestos, (3) industrial hygiene asbestos air monitoring data collected at this refinery and similar facilities since the early 1970s, (4) published and unpublished data sets on task-specific dust or fiber concentrations encountered in various industrial settings since the late 1930s, and (5) the evolution of respirator use and other workplace practices that occurred as the hazards of asbestos became better understood over time. Due to limited air monitoring data for most crafts, 8-h TWA fiber concentrations were calculated only for insulators, while all other crafts were estimated to have experienced 8-h TWA fiber concentrations at some fraction of that experienced by insulators. A probabilistic (Monte Carlo) model was used to account for potential variability in the various data sets and the uncertainty in our knowledge of selected input parameters used to estimate exposure. Significant reliance was also placed on our collective professional experiences working in the fields of industrial hygiene, exposure assessment, and process engineering over the last 40 yr. Insulators at this refinery were estimated to have experienced 50th (and 95th) percentile 8-h TWA asbestos exposures (which incorporated 8-h TWA fiber concentrations, respirator use and effectiveness, and time spent working with asbestos-containing materials) of 9 (16) fibers/cc (cubic centimeter) from 1940 to 1950, 8 (13) fibers/cc from 1951 to 1965, 2 (5) fibers/cc from 1966 to 1971, 0.3 (0.5) fibers/cc from 1972 to 1975, and 0.005 (0.02) fibers/cc from 1976 to 1985 (estimated exposures were <0.001 fibers/cc after 1985). Estimated 8-h TWA exposures for all other crafts were at least 50- to 100-fold less than that of insulators, with the exception of laborers, whose estimated 8-h TWA exposures were approximately one-fifth to one-tenth of those of insulators. In spite of the data gaps, the available evidence indicates that our estimates of 8-h TWA asbestos exposures reasonably characterize the typical range of values for these categories of workers over time

Mowat F, Weidling R, Sheehan P. Simulation tests to assess occupational exposure to airborne asbestos from asphalt-based roofing products. Ann Occup Hyg. 2007 Jul;51(5):451-62. Health Sciences, Exponent, Inc., 149 Commonwealth Drive, Menlo Park, CA 94025, USA.

This study sought to evaluate exposure from specific products to evaluate potential risk from roof repair activities. Five asbestos-containing fibered roof coatings and plastic cements, representing a broad range of these types of products, were tested in exposure simulations. These products were applied to representative roof substrates. Release of asbestos fibers during application and sanding of the product shortly thereafter (wet sanding) were tested initially. Other roof substrates were cured to simulate a product that had been on a rooftop for several months and then were tested to evaluate release of fibers during hand sanding and hand scraping activities. Additional tests were also conducted to evaluate asbestos release during product removal from tools and clothing. Two personal (n = 84) and background/clearance (n = 49) samples were collected during each 30-min test and analyzed for total fiber concentration [phase-contrast microscopy (PCM)] and for asbestos fiber count [transmission electron microscopy (TEM)]. PCM concentrations ranged from <0.005 to 0.032 fibers per cubic centimeter (f cc(-1)). Chrysotile fibers were detected in 28 of 84 personal samples collected. TEM concentrations ranged from <0.0021 to 0.056 f cc(-1). Calculated 8-h time-weighted averages (TWAs) ranged from 0.0003 to 0.002 f cc(-1) and were comparable to the background TWA concentration of 0.0002 f cc(-1) measured in this study. Based on these results, it is unlikely that roofers were exposed to airborne asbestos concentrations above the current or historical occupational guidelines during scraping and sanding of these products during roof repair.

Bang KM, Pinheiro GA, Wood JM, Syamlal G. Malignant mesothelioma mortality in the United States, 1999-2001. Int J Occup Environ Health. 2006 Jan-Mar;12(1):9-15. Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA.

Malignant mesothelioma is strongly associated with asbestos exposure. This paper describes demographic, geographic, and occupational distributions of mesothelioma mortality in the United States, 1999-2001. The data (n = 7,524) were obtained from the National Center for Health Statistics multiple-cause-of-death records. Mortality rates (per million per year) were age-adjusted to the 2000 U.S. standard population, and proportionate mortality ratios (PMRs) were calculated by occupation and industry, and adjusted for age, sex, and race. The overall age-adjusted mortality rate was 11.52, with males (22.34) showing a sixfold higher rate than females (3.94). Geographic distribution of mesothelioma mortality is predominantly coastal. Occupations with significantly elevated PMRs included plumbers/pipefitters and mechanical engineers. Industries with significantly elevated PMRs included ship and boat building and repairing, and industrial and miscellaneous chemicals. These surveillance findings can be useful in generating hypotheses and developing strategies to prevent mesothelioma.

Putzu MG, Bruno C, Zona A, Massiccio M, Pasetto R, Piolatto PG, Comba P. Fluoro-edenitic fibres in the sputum of subjects from Biancavilla (Sicily): a pilot study. Environ Health. 2006 Jun 16;5:20. Department of Traumatology, Orthopaedics and Occupational Medicine - University of Turin, Via Zuretti 29 - I-10126 Turin, Italy.

BACKGROUND: An excess of mortality for malignant neoplasms of the pleura in Biancavilla, promoted an investigation for pleural mesothelioma, disclosing 17 cases. As the absence of known sources of asbestos exposure, a local stone quarry, located near the inhabited area, used for the extraction of building materials, was investigated. Amphibolic fibres were found in the quarry and identified as fluoro-edenite "new end-member of the edenite / fluoro-edenite series" and recognized as the fluoro-edenite holotype by International Mineralogical Association--Commission on New Minerals and Mineral Names. A pilot study was performed to verify the feasibility of using spontaneous sputum as an exposure indicator for these fibres, in a context in which the use of aerosol-induced sputum technique would not be easily accepted. METHODS: Hypothesizing a behaviour of the new fibre analogous to that of asbestos, the determination of the free fibres and the ferruginous bodies in spontaneous sputum was carried out. Phase Contrast Optical Microscope and an Environmental Scanning Electron Microscope fitted with X-ray energy dispersive analysis system (micro-analysis) were used to examine the samples. The criteria for inclusion in the study were: 1) subjects hospitalized for exacerbation of chronic obstructive pulmonary disease symptoms, 2) age > or = 45 years, 3) residence in Biancavilla for at least 30 years. RESULTS: The preliminary findings are related to 12 subjects (7 females and 5 males). Uncoated fibres (with length > 5 microm, diameter < 3 microm, aspect ratio 3.1) and ferruginous bodies were searched. Six out of twelve subjects (4 females, 2 males) had at least one of the three samples positive for the presence of fluoro-edenite, confirmed by micro-analysis. The fibre concentration found in the sputum ranged from 0.04 to 10 fibres/g; the length from 20 to 40 microm, the diameter was < 0.5 microm. No ferruginous bodies were found in any of the samples. The four women with a positive sample were housewives. Of the two men with a positive sample, one was a farmer and the other a mason. Therefore, it may be assumed that the exposure to fluoro-edenitic fibres was mainly environmental. CONCLUSION: The occurrence of the pleural mesothelioma cases and the presence of fluoro-edenitic fibres in spontaneous sputum, evidence the need to study the biological activity of fluoro-edenitic fibres and the implementation of epidemiological monitoring systems.

Paustenbach DJ, Madl AK, Donovan E, Clark K, Fehling K, Lee TC. Chrysotile asbestos exposure associated with removal of automobile exhaust systems (ca. 1945-1975) by mechanics: results of a simulation study. J Expo Sci Environ Epidemiol. 2006 Mar;16(2):156-71. ChemRisk, Inc., San Francisco, CA 94105, USA.

For decades, asbestos-containing gaskets were used in virtually every system that involved the transport of fluids or gases. Prior to the mid-1970s, some automobile exhaust systems contained asbestos gaskets either at flanges along the exhaust pipes or at the exhaust manifolds of the engine. A limited number of automobile mufflers were lined with asbestos paper. This paper describes a simulation study that characterized personal and bystander exposures to asbestos during the removal of automobile exhaust systems (ca. 1945-1975) containing asbestos gaskets. A total of 16 pre-1974 vehicles with old or original exhaust systems were studied. Of the 16 vehicles, 12 contained asbestos gaskets in the exhaust system and two vehicles had asbestos lining inside the muffler. A total of 82 samples (23 personal, 38 bystander, and 21 indoor background) were analyzed by Phase Contrast Microscopy (PCM) and 88 samples (25 personal, 41 bystander, and 22 indoor background) by Transmission Electron Microscopy (TEM). Only seven of 25 worker samples analyzed by TEM detected asbestos fibers and 18 were below the analytical sensitivity limit (mean 0.013 f/cc, range 0.001-0.074 f/cc). Applying the ratio of asbestos fibers:total fibers (including non-asbestos) as determined by TEM to the PCM results showed an average (1 h) adjusted PCM worker exposure of 0.018 f/cc (0.002-0.04 f/cc). The average (1 h) adjusted PCM airborne concentration for bystanders was 0.008 f/cc (range 0.0008-0.015 f/cc). Assuming a mechanic can replace four automobile single exhaust systems in 1 workday, the estimated 8-h time-weighted average (TWA) for a mechanic performing this work was 0.01 f/cc. Under a scenario where a mechanic might repeatedly conduct exhaust work, these results suggest that exposures to asbestos from work with automobile exhaust systems during the 1950s through the 1970s containing asbestos gaskets were substantially below 0.1 f/cc, the current PEL for chrysotile asbestos, and quite often were not detectable.

Mowat F, Bono M, Lee RJ, Tamburello S, Paustenbach D. Occupational exposure to airborne asbestos from phenolic molding material (Bakelite) during sanding, drilling, and related activities. J Occup Environ Hyg. 2005 Oct;2(10):497-507. Exponent, Menlo Park, California 94025, USA.

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.

Paustenbach DJ, Sage A, Bono M, Mowat F. Occupational exposure to airborne asbestos from coatings, mastics, and adhesives. J Expo Anal Environ Epidemiol. 2004 May;14(3):234-44. Exponent, Menlo Park, California, USA.

Over the past few years, a question has arisen about the degree of exposure to airborne asbestos associated with the application, cleanup, and tear-out of glues and mastics used between 1940 and the present. These liquid products were used either to adhere insulation to pipes and boilers or to cover the insulation so as to protect it. In this study, four asbestos-containing products, a coating, two mastics, and an adhesive, which were representative of the various classes of products that have been used historically, were tested to determine the airborne concentration of asbestos fibers released during five different activities (application, spill cleanup, sanding, removal, and sweep cleaning). Each activity was performed for 30 min (often in triplicate). Personal (n=172) and area (n=280) air samples were collected during the tests, and each was analyzed for total fiber concentrations using phase contrast microscopy (PCM), and for asbestos fiber count using transmission electron microscopy (TEM). A measurable concentration of asbestos fibers was detected in six of the 452 samples collected (0.0017-0.0184 fibers/ml). The observed asbestos fibers counts for each product were similar to background. Only one asbestos fiber was detected in an indoor background sample; no asbestos fibers were identified in any of the outdoor background samples. The (raw) PCM-total fiber concentrations were adjusted based on TEM analyses that reported fraction of asbestos fibers (to derive a PCM-asbestos concentration) and by the fraction of the 8-h workday that a worker spends performing the activity (to derive a calculated TWA). For the coatings, mastics, and adhesives evaluated in the present study, the calculated TWAs using hypothetical work scenarios were well below the current Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) of 0.1 fibers/ml. The calculated TWAs ranged from 0.03 to 0.009 fibers/ml. The actual concentration of airborne asbestos due to these products is almost certainly much less than the TWAs, and may be so low as to not be measurable. These results support the historical view that these products, over the past 50 years, did not pose an occupational health hazard under foreseeable uses.

Strickler HD, Goedert JJ, Devesa SS, Lahey J, Fraumeni JF Jr, Rosenberg PSTrends in U.S. pleural mesothelioma incidence rates following simian virus 40 contamination of early poliovirus vaccines. J Natl Cancer Inst. 2003 Jan 1;95(1):38-45. Department of Epidemiology and Social Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA.

BACKGROUND: Poliovirus vaccines that were used during the late 1950s and early 1960s were contaminated with simian virus 40 (SV40), a monkey virus that is tumorigenic in rodents. SV40 DNA sequences have been detected in some human cancers, especially pleural mesotheliomas, although results are conflicting. We examined the relationship between SV40-contaminated poliovirus vaccine exposure and subsequent rates of pleural mesothelioma in the United States. METHODS: We used data from the Surveillance, Epidemiology, and End Results Program to estimate age- and sex-specific pleural mesothelioma incidence rates per 10(5) person-years (py) from 1975 through 1997 and the Poisson distribution to determine 95% confidence intervals (CIs) for each rate. The prevalence, by birth cohort, of poliovirus vaccine exposure during the period of widespread SV40 contamination was determined from published survey data. Trends in mesothelioma incidence rates were assessed by examining age- and sex-specific rates over calendar periods and with the use of the age-period-cohort model. Trends in mesothelioma incidence were then compared with trends in prevalence of exposure. All statistical tests were two-sided. RESULTS: The age-standardized pleural mesothelioma incidence rate for 1975 through 1997 was 1.29/10(5) py (95% CI = 1.24/10(5) to 1.34/10(5) py) in males and 0.21/10(5) py (95% CI = 0.20/10(5) to 0.23/10(5) py) in females. The rate in males increased from 0.79/10(5) py (95% CI = 0.62/10(5) to 1.0/10(5) py) in 1975 to a peak of 1.69/10(5) py (95% CI = 1.46/10(5) to 1.95/10(5) py) in 1992. Incidence rates increased the most among males who were 75 years of age or older, the age group least likely to have been immunized against poliovirus. Incidence rates among males in the age groups most heavily exposed to SV40-contaminated poliovirus vaccine remained stable or decreased from 1975 through 1997. Similar age-specific trends were observed among females. The age-period-cohort models for men and women also indicated that the trends in pleural mesothelioma incidence were not related to trends in exposure to SV40-contaminated poliovirus vaccine. CONCLUSIONS: Age-specific trends in U.S. pleural mesothelioma incidence rates are not consistent with an effect of exposure to SV40-contaminated poliovirus vaccine. Nonetheless, given reports of the detection of SV40 genomic DNA sequences in human mesotheliomas, monitoring of vaccine-exposed cohorts should continue.

Price B, Ware A. Mesothelioma trends in the United States: an update based on Surveillance, Epidemiology, and End Results Program data for 1973 through 2003. Am J Epidemiol. 2004 Jan 15;159(2):107-12. Price Associates, Inc., White Plains, NY 10601, USA.

Using 1973-2000 mesothelioma incidence data released by the Surveillance, Epidemiology, and End Results Program in April 2003, the authors estimated the parameters of a birth-cohort and age model to determine whether previously reported patterns of mesothelioma in the United States have changed. Compared with analyses based on data through 1992, a slower decline was found in male cases immediately after a peak in 2000-2004, but no other notable changes in the time pattern were detected. Analysis confirmed that the annual number of male mesothelioma cases, which increased steeply from the 1970s through the mid-1990s, has leveled off in terms of both the age-adjusted rate and the absolute numbers of cases. After a peak of approximately 2,000 cases, a return to background levels is expected by 2055. The total projected number of male mesothelioma cases in 2003-2054 is approximately 71,000. The maximum lifetime risk for males, which occurs for the 1925-1929 birth cohort, is 1.8 x 10(-3). The age-adjusted rate for females is constant, as are the female lifetime mesothelioma risk across birth cohorts (3.6 x 10(-4)) and the annual risk (3.9 x 10(-6)). The time pattern of cases for females supports the existence of a threshold exposure for mesothelioma and a quantifiable background rate.

Jemal A, Grauman D, Devesa S. Recent geographic patterns of lung cancer and mesothelioma mortality rates in 49 shipyard counties in the United States, 1970-94. Am J Ind Med. 2000 May;37(5):512-21. Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, Maryland 20892-7244, USA.

BACKGROUND: Lung cancer mortality rates among white males in the United States were observed to be elevated during 1950-69 in counties with shipbuilding industries during World War II; risk was found to be associated with asbestos exposure. We evaluated the geographic patterns in more recent years, 1970-94, for whites and compared them with the 1950-69 patterns. METHODS: We calculated age-adjusted rates and estimated rate ratios between comparison groups. RESULTS: Rates generally were higher in shipyard counties than in all nonshipyard counties and in coastal nonshipyard counties for both sexes and time periods. Rates increased markedly from 1950-69 to 1970-94 in all groups, with the changes more pronounced in females than males. Pleural mesothelioma mortality rates were also significantly higher in shipyard counties than coastal nonshipyard counties in all regions among males but not among females. CONCLUSIONS: The more pronounced changes in lung cancer mortality rates among females in shipyard counties may be attributed to the combined effects of low asbestos exposures and changes in smoking behavior.

Desoubeaux N, Bouvier V, Gervais R, Galateau-Salle F, Thibon P, Leplumey T, Herbert C, Lecherbonnier Y, Daviet JP, Letourneux M. Malignant mesothelioma in Basse-Normandie, a French population study. Descriptive analysis, prognostic factors and survival [Article in French]. Rev Epidemiol Sante Publique. 2001 Dec;49(6):523-9. Fédération des Registres de Basse-Normandie, Avenue Cte de Nacre, CHU Caen, 14032 Caen Cedex, France.

BACKGROUND: Malignant mesothelioma is a pleural and/or peritoneal tumor closely related to asbestos exposure, and its incidence should continue to increase during the first two decades of the 21(rst)century. The main prognostic factors described for this tumor are older age, sex, tumor stage and histological type. The aim of this study was to assess the incidence of pleural and peritoneal malignant mesothelioma in the County of Basse-Normandie (France), as well as their epidemiological characteristics, and the prognostic factors related to survival duration. METHODS: Cases were identified through repeated inquiries among all chest physicians and pathologists of the County of Basse-Normandie. A special care was taken in the validation of the diagnosis of each case. Incidence of mesothelioma was determined according to sex and age (5 years categories). Qualitative and quantitative variables were compared with the use of chi-square or Student's t tests respectively. Survival rate was calculated by Kaplan-Meier method, and prognostic factors were studied by means of Cox model. RESULTS: Study population consisted in all 80 malignant mesothelioma cases diagnosed in Basse-Normandie between the 1(rst) of September 1995 and the 31(rst) of August 1999. Annual incidence rates of pleural mesothelioma were 1.1/100 000 in men and 0.23/100 000 in women; annual incidence rates for peritoneal mesothelioma were 0.21/100 000 in men and 0.13/100 000 in women. Asbestos exposure was present in 63 cases (78.8%). The study of geographic distribution of mesothelioma cases revealed the influence of the main asbestos industrial settings, as well as the numerous scattered cases related to other occupational exposure. Mean survival duration was 9 months for pleural mesothelioma and 5 months for peritoneal mesothelioma. After adjustment on age, death risk was higher in asbestos-exposed than in non asbestos-exposed cases. CONCLUSION: This study confirms that malignant mesothelioma is closely related to asbestos exposure, but not only in main asbestos industrial settings. It suggests that asbestos exposure may take place among prognostic factors of this tumor.

Tossavainen A, Kovalevsky E, Vanhala E, Tuomi T. Pulmonary mineral fibers after occupational and environmental exposure to asbestos in the Russian chrysotile industry. Am J Ind Med. 2000 Apr;37(4):327-33. Finnish Institute of Occupational Health, Helsinki, Finland.

BACKGROUND: As an indicator of occupational, domestic, and environmental exposure, the level and type of asbestos fibers were determined from lung tissue samples of workers and residents who resided in the area of the world's largest asbestos mine at Asbest, Russia. METHODS: Electron microscopy was used to analyze and measure the concentration of asbestos fibers in a series of 47 autopsies at the Asbest Town Hospital. Work histories were obtained from pathology reports and employment records. RESULTS: In 24 chrysotile miners, millers, and product manufacturers, the pulmonary concentrations of retained fibers (over 1 microm in length) were 0. 8-50.6 million f/g for chrysotile, and < 0.1-1.9 million f/g for amphiboles (tremolite and anthophyllite). The concentrations were lower in 23 persons without any known occupational contact with asbestos; 0.1-14.6 million f/g for chrysotile, and < 0.1-0.7 million f/g for amphiboles. On average, 90% of all inorganic fibers were chrysotile, and 5% tremolite/anthophyllite. No amosite or crocidolite fibers were detected in any of the samples. CONCLUSIONS: The mean and range of pulmonary chrysotile concentrations were about the same as reported previously from the Canadian mining and milling industry. In the Russian samples, the mean concentration of tremolite fibers were less by at least one order of magnitude. Occupational contact was the most important source of asbestos exposure.

Mlynarek S, Corn M, Blake C. Asbestos exposure of building maintenance personnel. Regul Toxicol Pharmacol. 1996 Jun;23(3):213-24. Department of Environmental Health Sciences, School of Hygiene and Public Health, Johns Hopkins University, 615 N. Wolfe Street, Baltimore, Maryland, 21205, USA.

The exposures of building maintenance personnel and occupants to airborne asbestos fibers, and the effects of operations and maintenance programs on those exposures, continue to be an important public health issue. The subject of this investigation was a large metropolitan county with numerous public buildings which routinely conducted air sampling for asbestos. A total of 302 personal air samples in nine task categories collected during maintenance worker activities in proximity to asbestos-containing materials were analyzed; 102 environmental air samples in four task categories were also analyzed. The arithmetic means of the 8-hr time weighted average exposures for personal sampling for each task category were all below the Occupational Safety and Health Administration permissible exposure level of 0.1 fibers (f)/cc > 5 microm. The highest mean 8-hr time weighted average exposure was 0.030 f/cc > 5 microm for ceiling tile replacement. The maximum asbestos concentration during sample collection for environmental samples was 0.027 f/cc > 5 microm. All asbestos-related maintenance work was done within the framework of an Operations and Maintenance Program (OMP) which utilized both personal protective equipment and controls against fiber release/dispersion. Results are presented in association with specific OMP procedures or controls. These results support the effectiveness of using Operations and Maintenance Programs to manage asbestos in buildings without incurring unacceptable risk to maintenance workers performing maintenance tasks.

Corn M. Airborne concentrations of asbestos in non-occupational environments. Ann Occup Hyg. 1994 Aug;38(4):495-502.

Concentrations of asbestos in air were determined from analysis of samples collected in over 300 buildings involved in litigation. Samples were collected by certified industrial hygienists and analysed in certified laboratories by transmission electron microscopy. Building group mean concentrations of asbestos in building air inhaled by occupants were generally less than 0.0005 f ml-5 > 5 microns (90th percentile). At these concentrations the risk from asbestos exposure would be very low for building occupants. Another data set was obtained from the maintenance logs kept by owners of buildings containing asbestos fireproofing and subject to Operations and Maintenance Programmes to evaluate asbestos inhalation risk to maintenance workers. The logs were kept to document protective measures and maintenance personnel exposures during 1991-1992. Data are presented for one commercial building, which is typical of data for three additional commercial buildings and a medical centre. All samples were evaluated by the NIOSH 1400 protocol for sampling and analysis by phase contrast microscopy. Operations and maintenance precautions to reduce dust emission were modest; they included spraying of ceiling tiles with amended water, HEPA vacuuming tile edges before entry and after tile replacement, respirator usage and careful work. Negative pressure containment was not used. In this building personal exposures in electrical/plumbing work ranged from 0.000 to 0.035 f ml-1 > 5 microns in length (average work time of one job was 118 min); the 8-h TWA was 0.0149 f ml-1 > 5 microns.(ABSTRACT TRUNCATED AT 250 WORDS)

Price B, Crump KS, Baird EC 3rd. Airborne asbestos levels in buildings: maintenance worker and occupant exposures. J Expo Anal Environ Epidemiol. 1992 Jul-Sep;2(3):357-74. Price Associates, Inc., Washington, DC 20006.

A substantial number of air samples have been collected during the past few years to measure airborne asbestos levels in buildings with asbestos-containing materials (ACM). These samples fall into two categories: (i) samples collected to measure the exposure of workers while they were engaged in routine maintenance and repair activities; and (ii) samples collected during normal building activity to measure prevalent levels in buildings. The measurements derived from these samples have been compiled and summarized to provide estimates of the airborne asbestos exposure of workers engaged in routine maintenance and repair work and by other building occupants. These data indicate that maintenance and repair workers in buildings with ACM, after accounting for the frequency and duration of these types of activities, have annual exposure levels ranging from a median value of 0.002 fibers per cubic centimeter (f/cc) per year to 0.02 f/cc per year at the 90th percentile. Building occupants not involved in maintenance and repair work experience average exposure levels ranging from 0.00003 f/cc to 0.0005 f/cc.



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