Levels Of Asbestos Research Articles

Libby: the long legacy of a public health disaster

Libby: the long legacy of a public health disaster

우리나라 석면함유제품 취급 사업장의 공기 중 석면 농도의 시간적 변화

Objectives: The purpose of this study was to evaluate trends in asbestos exposure among asbestos-handling industries from 2000 to 2005. Methods: The data included the number of industries and workers exposed, concentrations of asbestos and the amount exceeded, and the type and size of industry by year. These data were collected by 46 regional employment and labor offices in Korea using work environment monitoring reports. A total of 1,481 samples from 284 industries were extracted from the reports and were analyzed with no data modification. Results: The means of asbestos concentration decreased from <TEX>$0.84f/cm^3$</TEX> to <TEX>$0.03f/cm^3$</TEX> during the period 2000-2005. Among the total of 1,481 samples, 11 samples(0.7%) exceeded the KOEL, and 178 samples(12.0%) were ACGIH TLV. The insulating paper product manufacturing industry was found to have the highest level of asbestos, followed by the fireproofing manufacturing industry, brake lining products manufacturing industry, commutator products manufacturing industries, and construction materials manufacturing industry. The number of asbestos handling industries decreased from 48 industries with 1,155 employees to 37 industries during the period of 2000 to 2005, but the number of asbestos workers expanded to the point that 1,182 employees could be found in 2005. Conclusion: Based on these results, the strengthening of the KOEL and new regulations turned out to help reduce asbestos exposure levels. This study recommends that retrospective exposure to asbestos based on various industry types should be assessed.

Evaluation of thermally treated asbestos based on fiber number concentration determined by transmission electron microscopy

Appropriate treatment of asbestos waste is a significant problem. In Japan, inertization of asbestos-containing waste by novel techniques approved by the Ministry of the Environment is now promoted. A quantitative method of testing with high sensitivity to the asbestos levels present in the inertization products is required for the approval process, but many testing methods are only qualitative. Thus, we have developed an evaluation method for asbestos in inertized products, consisting of the extraction of fibers from inertized products and determination of fiber number concentration by transmission electron microscopy. We adopted this testing method to evaluate thermally treated asbestos. It was found that fiber number concentrations of thermally treated asbestos decreased with increased treatment temperature, and were below the environmental level (102 Mf/g) at more than 1000 °C for chrysotile and crocidolite and more than 1400 °C for amosite and other amphibole forms of asbestos.

Measurement of airborne asbestos levels in high traffic areas of Shiraz, Iran, in winter 2014

Aims: Levels of asbestos fibers in ambient air of dense areas of Shiraz, Iran, were monitored in winter 2014. Materials and Methods: Sampling was carried out by directing air flow to a mixed cellulose ester membrane filter mounted on an open-faced filter holder using a low flow sampling pump. Fiber counting on the filters was conducted using both phase contrast microscopy (PCM) method to determine total fibers and scanning electron microscopy (SEM) method to identify nonasbestos from asbestos fibers. Results: The average concentration of asbestos fibers in the ambient air of the study in different areas of Shiraz were 1.18 ± 0.28 PCM f/L and 13.64 ± 2.87 SEM f/L, in which a maximum level was measured in Valiasr square (1.89 ± 0.54 PCM f/L [20.37 ± 5.55 SEM f/L]), and that of in Moallem square was in minimum (1.05 ± 0.47 PCM f/L [12.24 ± 3.04 SEM f/L]). Conclusions: The averages of asbestos fibers in all sampling points were higher than the WHO suggested standards for ambient air (0.05 PCM f/L, 2.2 SEM f/L). This may be attributed to the frequent occurrence of heavy traffic, the existence of relevant industries in and around the city, and the topographic characteristics of the city. Therefore, immediate courses of action such as product substitution, traffic smoothing, and industrial sites relocating should be taken to eliminate asbestos fibers emission.

Factors influencing the retrofitting of existing office buildings using Adelaide, South Australia as a case study

Purpose– The purpose of this paper is to explore the barriers preventing investment in the re-use of low-grade multi-storey building stock in order to identify attributes that determine whether an existing building is suitable for retrofitting.Design/methodology/approach– Semi-structured interviews were undertaken with key industry practitioners to investigate existing practices and barriers facing low-grade building retrofits and what “ideal” multi-storey building features represent a successful investment opportunity.Findings– The findings showed that tenant commitment is necessary before any project goes ahead and that there exist many barriers influencing the investment decision. These include: high levels of asbestos found in existing buildings; changes in the National Construction Code necessitating enhanced fire safety and disability access; heritage listing; lack of awareness; overestimation of costs involved on simple and effective energy efficiency upgrades and change in tenant demands towards modern and efficient open plan offices. Many low-grade structures are privately owned inherited assets where the owners lack the expertise and capital to undertake retrofitting effectively.Research limitations/implications– The study is focused on the Adelaide CBD in South Australia but the findings are relevant to other Australian cities.Practical implications– There is room in the market for more positive and influential schemes such as the Green Building Fund that encourage more energy efficiency upgrading of these buildings.Social implications– The greater occurrence of retrofitting and re-use of older buildings, rather than demolition and rebuilding, has advantages with regard to reducing the impact of buildings on the environment and promoting sustainability.Originality/value– The research has indicated certain features of older buildings which render them as suitable candidates for retrofitting and refurbishment.

Esophagus cancer and occupational exposure to asbestos: results from a meta-analysis of epidemiology studies.

The relationship between occupational asbestos exposure and esophagus cancer (EC) is not fully understood. We performed a meta-analysis to quantitatively assess the association. We systematically searched databases of PubMed, EMBASE, and Web of Science for studies with quantitative estimates of asbestos exposure and EC mortality. Pooled standardized mortality ratios (SMRs) and their corresponding 95% confidence intervals (CIs) were calculated. Twenty cohort studies on EC and asbestos exposure were included in this meta-analysis. Overall, occupational exposure to asbestos was associated with an excess risk of EC (SMR = 1.24, 95% CI: 1.13-1.38, P < 0.001), with little evidence of heterogeneity among studies (I(2) = 0.0%, P = 0.682). Being male, exposure to chrysotile or mixed asbestos, working at textile industry, long study follow-up (≥20 years), Asia, Europe and America cohorts with larger cohort size (>500), and high-exposure group all contribute to significantly higher SMR. Publication bias was not detected (Egger's test P-value = 0.374). This meta-analysis suggested that occupational asbestos exposure might be associated with an increased risk of EC in male. High-exposure level of asbestos could contribute to significantly higher risk of EC mortality.

Red-Alarm against Fibers Concentration of Asbestos in Atmospheric Urban Area of Tehran Capital of Iran

Asbestos is the natural silicate minerals with attractive physical properties such as; resistant to fire, electrical and chemical solvents. It composes of six types of materials include; Serpentine group; Chrysotile, Amphibole groups; amosite (Brown), Crocidolite (Blue) and other materials. It is popular for low cost favorable properties. All the six types have asbestiform fiber crystal, and can induce carcinogen in human. It was generally used during the boom of the industrial revolution since 1866, and the first publish of the unhealthy effect of asbestos reported nearly 30 years after industrial usage since 1899. The most common usage types of asbestos consist of chrysotile and the crocidolite. All the current types widely use in the building structures, brake pads (1) and clutch disc (2). Daily inhalation of asbestos occurs in the ambient air of cities which associated with poor air quality control. This event leads to generation of asbestosis disease (3), cancer development and mortality (4) and morbidity among at-risk population, such as asbestos –exposed workers (5), non-occupational subjects, people who living in the asbestos fibers exposed environment (6). Corresponding author: Agin Kh, MD. Associated Professor of the Respiratory Medicine. Logman Hakeem General Teaching Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran E-mail: khosrow.agin@yahoo.com & Agin@sbmu.ac.ir Long time exposure with asbestos leads to the development of chronic lung disease. It can be developed as occupational and non-occupational conditions (7, 8). Mesothelioma and lung cancer are the known causes of the asbestos exposure (9). In addition, it produces risk development of esophageal gastric, colorectal cancer (10) and head and neck squamous cell carcinoma (11). Children also are at risk of cancer by asbestos inhalation (12). The accepted threshold for asbestos is 100 fiber/liter that measured by phase-contrast optical microscopy (PCM) (13). There is a direct relationship between high level of asbestos in air and lung cancer (14). The first use of asbestos in Iran returns to World War II during the foundation of railroad and beginning product of cement manufacture in 1958 (15). Meanwhile, asbestos is producing up to 55000 tones cement in Iran annually, and near the 94% of produced cement that used in our country. The current output predominantly detected in the manufacture of building material (16), as pipe in the water delivery network (5000 Kilometer), brake pads (17) and pad shoes (15, 18). The most common types of asbestos observed in the ambient urban area of Tehran, including; Chrysotil (60%), tremolite (10%), antophylline (10%) (19). The rate of asbestos in air of Tehran- Iran was 68 times higher in the USA in 2009 (19). Our ministry of health in 2013 reported that the asbestos levels in the Tehran was 50-100 times more than the standard definition of the world (20). It seems that the deadline of depreciating has been finalized to the issue of asbestos fibers in our atmospheric cities. It requires a national decision, though the creating practice planes in reducing the level of usage and replacement that with safe materials.

Anguishing Reports of Ambient Air Pollution in Tehran Capital of Iran

Benzene is the aromatic hydrocarbon, organic and petrochemicals. It has high octane number and used as ethybenzene. It composed a few percent of gasoline mass less than 1%. Benzene was used before 1950 but after that year replaced with tetraethyl lead. The recent material was associated with environmental pollution so came back again benzene in the petrol cycle production. Human is exposed withbenzeneby several ruts; gasoline fumes, motor vehicle exhaust, and smoking. Inhalation is the main route of toxicity in urban area. Standard threshold of benzene concentration is 1.56 part per billion (PPB) in accepted air quality. The current study displayed that benzene concentrationin Tehran (capital of Iran) was between 2-20 times higher than the standard (1). This is the first official report published aboutambient air pollution in 2013. However,IranMinistry of Health announced that Asbestos and benzene levels had 50-100, respectively. It means that there were 10 times more than standard levels in the Tehran urban area(2). These materials, specially benzeneBenzene has potential ability as cancer risk factor to inducing acute and chronic bloods leukemia (3). In addition, there arerelations between benzene exposure and lung cancer (4). Benzene can induce aryl hydrocarbon receptor which leads to tumorigenesis (5). The vision of information dictates assumption of planning in two aspects. The arrangement may be suggestedthat the sources of pollutants will be reduced in the environment thought activation of dependable organizations and investigation of at-risk population based on the prioritizes.

Occupational asbestos exposure and risk of esophageal, gastric and colorectal cancer in the prospective Netherlands Cohort Study

The evidence for an association between occupational asbestos exposure and esophageal, gastric and colorectal cancer is limited. We studied this association specifically addressing risk differences between relatively low and high exposure, risk associated with cancer subtypes, the influence of potential confounders and the interaction between asbestos and smoking in relation to cancer risk. Using the Netherlands Cohort Study (n = 58,279 men, aged 55-69 years at baseline), asbestos exposure was estimated by linkage to a job-exposure matrix. After 17.3 years of follow-up, 187 esophageal, 486 gastric and 1,724 colorectal cancer cases were available for analysis. The models adjusted for age and family history of cancer showed that mainly (prolonged) exposure to high levels of asbestos was statistically significantly associated with risk of esophageal adenocarcinoma (EAC), total and distal colon cancer and rectal cancer. For overall gastric cancer and gastric non-cardia adenocarcinoma (GNCA), also exposure to lower levels of asbestos was associated. Additional adjustment for lifestyle confounders, especially smoking status, yielded non-significant associations with overall gastric cancer and GNCA in the multivariable-adjusted model, except for the prolonged highly exposed subjects (tertile 3 vs. never: HR 2.67, 95% CI: 1.11-6.44 and HR 3.35, 95% CI: 1.33-8.44, respectively). No statistically significant additive or multiplicative interaction between asbestos and smoking was observed for any of the studied cancers. This prospective population-based study showed that (prolonged) high asbestos exposure was associated with overall gastric cancer, EAC, GNCA, total and distal colon cancer and rectal cancer.

Quantitative analysis of trace level asbestos in pharmaceutical talc by powder X-ray diffraction

As a traditional Chinese medicine and excipient, talc is widely used in medical and pharmaceutical fields. It may be contaminated with asbestos (including tremolite and chrysotile). Asbestos is known to be a carcinogen and it can cause lung cancer. Therefore, it is important to determine the concentration of asbestos in talc. This paper reports the use of powder X-ray diffraction (PXRD) technology to establish a trace level concentration detection of asbestos in traditional medicinal talc at 0.3 to 0.8%. The results show that the method is reliable, sensitive and suitable for its intended use of detecting trace levels of asbestos in the talc. Among the fifty-four talc samples, nine of them were found to contain asbestos and were disqualified. The passing rate of the test is 83.3%, which means it is necessary to establish an effective method to determine trace level asbestos in talc.

Domestic asbestos exposure: a review of epidemiologic and exposure data.

Inhalation of asbestos resulting from living with and handling the clothing of workers directly exposed to asbestos has been established as a possible contributor to disease. This review evaluates epidemiologic studies of asbestos-related disease or conditions (mesothelioma, lung cancer, and pleural and interstitial abnormalities) among domestically exposed individuals and exposure studies that provide either direct exposure measurements or surrogate measures of asbestos exposure. A meta-analysis of studies providing relative risk estimates (n = 12) of mesothelioma was performed, resulting in a summary relative risk estimate (SRRE) of 5.02 (95% confidence interval [CI]: 2.48–10.13). This SRRE pertains to persons domestically exposed via workers involved in occupations with a traditionally high risk of disease from exposure to asbestos (i.e., asbestos product manufacturing workers, insulators, shipyard workers, and asbestos miners). The epidemiologic studies also show an elevated risk of interstitial, but more likely pleural, abnormalities (n = 6), though only half accounted for confounding exposures. The studies are limited with regard to lung cancer (n = 2). Several exposure-related studies describe results from airborne samples collected within the home (n = 3), during laundering of contaminated clothing (n = 1) or in controlled exposure simulations (n = 5) of domestic exposures, the latter of which were generally associated with low-level chrysotile-exposed workers. Lung burden studies (n = 6) were also evaluated as a surrogate of exposure. In general, available results for domestic exposures are lower than the workers’ exposures. Recent simulations of low-level chrysotile-exposed workers indicate asbestos levels commensurate with background concentrations in those exposed domestically.

Ambient monitoring of airborne asbestos in non-occupational environments in Tehran, Iran

Airborne asbestos fiber concentrations were monitored in the urban areas of Tehran, Iran during the period of 23 August to 21 September 2012. The airborne fiber concentrations of 110 air samples collected from 15 different sites in five regions of Tehran. The monitoring sites were located 2.5 m above ground nearby the main street and heavy traffic jam. The ambient air samples were analyzed using scanning electron microscopy (SEM), with energy-dispersive X-ray analysis and phase-contrast optical microscopy (PCM). The geometric means of the airborne asbestos fiber concentrations in the outdoor living areas was 1.6 × 10−2 SEM f ml−1 (1.18 × 10−3 PCM f ml−1). This criteria is considerably higher than those reported for the levels of asbestos in outdoor living areas in the Europe and the non-occupational environment of the Korea. No clear correlation was found between asbestos fiber concentration and the relative humidity and temperature. The SEM and PLM analysis revealed that all samples examined contained only chrysotile asbestos. It can be concluded that several factor such as heavy traffic, cement sheet and pipe consumption of asbestos, and geographical conditions play an important role for the high airborne asbestos levels in the non-occupational environments.

Lung cancer and mesothelioma risk assessment for a population environmentally exposed to asbestos

Asbestos-related cancer risk is usually a concern restricted to occupational settings. However, recent published data on asbestos environmental concentrations in Thetford Mines, a mining city in Quebec, Canada, provided an opportunity to undertake a prospective cancer risk assessment in the general population exposed to these concentrations. Using an updated Berman and Crump dose-response model for asbestos exposure, we selected population-specific potency factors for lung cancer and mesothelioma. These factors were evaluated on the basis of population-specific cancer data attributed to the studied area's past environmental levels of asbestos. We also used more recent population-specific mortality data along with the validated potency factors to generate corresponding inhalation unit risks. These unit risks were then combined with recent environmental measurements made in the mining town to calculate estimated lifetime risk of asbestos-induced lung cancer and mesothelioma. Depending on the chosen potency factors, the lifetime mortality risks varied between 0.7 and 2.6 per 100,000 for lung cancer and between 0.7 and 2.3 per 100,000 for mesothelioma. In conclusion, the estimated lifetime cancer risk for both cancers combined is close to Health Canada's threshold for "negligible" lifetime cancer risks. However, the risks estimated are subject to several uncertainties and should be confirmed by future mortality rates attributed to present day asbestos exposure.

Asbestos and Its Toxicological Concern

phagocytosis. Further longer fibers are cleared only after fragmentation, splitting or dissolution and retained in the lungs for a long time. Due to the differences in structure and length, chrysotile has high affinity to be deposited in the upper airways of the respiratory tract and also cleared efficiently from the lungs compared with amphibole fibers [3]. Shorter fibers retained in the lungs for prolonged periods and further they penetrate the epithelial cells into the lymphatic system or the blood and simultaneously reach kidney and gets excreted. Asbestos enter into a person by breathing and deposited in lung tissues and accumulates over time and causes irritation, scarring and inflammation and eventually produces severe health implications [49]. Therefore, asbestos has been classified as human carcinogens. A history of asbestos exposure at occupational exposure is reported in about 70% to 80% of all cases of mesothelioma (a rare type of cancer of the mesothelium-the membrane that covers and protects most of the internal organs of the body). The main symptoms of mesothelioma of the lungs are shortness of breath, chest pain and abdominal mesothelioma include weight loss, swelling and pain in the abdomen, blood clotting abnormalities, bowel obstruction, anemia and fever. Continued exposure to high levels of asbestos in the occupational exposure scenario can also cause asbestosis (e.g., disease that can lead to disability and death and it scars the lungs and can cause the heart to enlarge). The primary symptoms of asbestosis are shortness of breath, persistent cough that produces mucus, chest tightness, chest pain, loss of appetite, dry, crackling sound in the lungs while inhaling followed by lung cancer with the symptoms of cough (including coughing up blood), wheezing, unexplained weight loss, difficulty breathing or shortness of breath, hoarseness and anemia. Clinical signs and symptoms of asbestosis include basal crackles on auscultation, dyspnea, cough and abnormal gas exchange, which may ultimately lead to death. The prolonged asbestos fiber particle exposure is associated with severe health illnesses including pulmonary fibrosis, bronchogenic carcinoma, diffuse malignant, parenchymal asbestosis (prolonged inflammatory response stimulated by the presence of fibres in the lung, leading to fibrosis of the lung parenchyma and permanent damage to the lung system), mesothelioma of the pleura and peritoneum, pleural abnormalities such as effusions (excessive fluid collections in lung tissues and chest cavity), pleural plaques/thickening (changes in lung membrane and visceral pleura and discrete fibrous or calcified thickened areas that arise from the surface of the parietal pleura which is observed in 20 to 60 percent of the occupationally exposed

Trades of dangers: A study of asbestos industry transfer cases in Asia

In a study of asbestos industry transfers in Asia, we examined the transfer of health and safety measures at the time of industry transfer and resulting health outcomes thereafter. Field surveys were conducted in Japan, Germany, Indonesia, and South Korea over a 5 year period beginning in 2007. The surveys involved interviews and field assessments of health and safety conditions. Even when there were transfers of entire engineering plant processes, we observed that the health and safety measures that should have accompanied the transfer, including technical capacities of risk assessment and management, regulatory protection, and cultural practices, were not actually transferred. According to work environment assessment records, there were differences in airborne asbestos levels of approximately 5-6 fibers/cc between the exporting and importing sides of the transfer. This amounted to a 10 years of time delay in comparable health and safety conditions. These differences resulted in repeated adverse health consequences at each factory operation site. Dangerous transfers of asbestos industry technology have occurred repeatedly over the years with the result that Asia has become the largest consumer of asbestos in the world. No effective internationally accepted safety measures have been introduced in the region. The study results support the need for both improved public awareness and international cooperation, such as sharing of substitute material technologies by the exporting countries, and provide the rationale for the creation of an Asian fund for asbestos victims.

Demonstration study of high temperature melting for asbestos-containing waste (ACW)

The service life of many buildings and houses built using asbestos-containing materials is coming to an end and their demolition will lead to a great deal of asbestos-containing waste (ACW). Conventionally, the disposal of such waste is conducted by isolation under controlled landfill procedures; however problems with this method exist, such as the risk at the time of re-utilization of landfill sites and the depletion of lands to be reclaimed. Melting treatment is a promising technology that could be used to solve these problems; a thermal process involving temperatures exceeding the melting points of asbestos, it transforms them into non-hazardous minerals. This technology may be applicable not only for friable ACW but also for nonfriable ACW. We performed a demonstration test of melting treatment of nonfriable ACW using a gasification and melting furnace of the shaft furnace type, which is a typical method for high temperature melting. Detailed observation using transmission electron microscopy as well as general analyses verified that the same level of asbestos remained in the slag obtained by high temperature melting as that of the background soil. In addition, the asbestos concentration in the exhaust gas and the dust from the facility were at sufficiently low levels, and it was thus verified that the asbestos concentration in the atmosphere in the vicinity of the facility during the melting treatment was comparable to that of Japan’s background level reported by the Ministry of the Environment in 2007.

Contenido pulmonar de amianto en trabajadores de los astilleros de Ferrol

Background and objectiveIn the last years, a study is being conducted about exposure to asbestos among shipyards workers in order to know the diagnosis of the diseases associated with the exposure. Our goal was to know the asbestos pulmonary contents in this population. Material and methodsWe obtained autopsy pulmonary samples from individuals who had worked in Ferrol shipyards. We analyzed samples from both lungs in most cases. After removing the lung organic matter with sodium hypochlorite, the inorganic residue was analyzed with optic microscopy. Results were expressed as asbestos bodies (AB) per gram of dry tissue. We considered as disease causative levels those above 1,000 AB/g. ResultsWe studied 30 males, with a mean age of 67 years (r: 56-89 years). Twenty-six were smokers or former smokers, and 4 had never smoked. All had a lung, pleural or peritoneal disease related to asbestos exposure (16 lung cancer, 6 mesothelioma, 25 benign pleural disease). Only in 6 out of the 16 lung cancer cases there was coexisting asbestosis. The median (interval) of AB was 6,171 (249-4,660,059) AB/g. Ninety-seven per cent of individuals had levels above 1,000 AB/g. There was a correlation between AB and age (r=.5676; P=.0011). ConclusionsWorkers from Ferrol shipyards who were analyzed had increased pulmonary levels of asbestos. It is essential to raise clinical suspicion of asbestos as a factor that can potentially cause lung disease in this group.

Cancer mortality of chrysotile asbestos worker cohort in China

ObjectivesThe association between lung cancer and chrysotile exposure remains an interesting and debated topic. This study is to analyse cancer mortality and to evaluate its association with asbestos exposure.MethodsA total...

Evaluation of Asbestos in Dust on Surfaces by Micro-Vacuum and Wipe Sampling

Abstract Micro-vacuum and wipe sampling methods are routinely used to measure surface dust contamination in both occupational and environmental settings. Both methods are subject to variability in their efficiency of dust collection resulting primarily from textural surface characteristics and dust loading. As part of a study to determine contamination levels of asbestos and other World Trade Center related contaminants in the wall cavity of a high-rise office building, paired samples were collected from 15 locations. The surface type of 14 locations was concrete-masonry block; the remaining surface type was a polyvinyl chloride coating. Micro-vacuum wipe pairs were obtained from the same wall component at contiguous locations. A template was used to ensure that equal 100-cm2 areas were consistently sampled. Micro-vacuum and wipe samples were collected and analyzed for asbestos using ASTM Methods D5756 and D6480, respectively. The average surface concentration reported by the micro-vacuum samples was numerically higher than the wipe samples, but the difference was not statistically significant (P=0.195). Both methods yielded an equal number of samples below the analytical sensitivity; the false-negative rates were the same for each method. Micro-vacuum and wipe sample concentrations were not correlated (R2=0.207). The length and width of asbestos structures collected by wipe samples was significantly larger than by micro-vacuum samples (P=&amp;lt;0.001). Micro-vacuum sampling for asbestos in dust on rough surfaces yields numerically higher concentrations of asbestos. Despite variations in the relative efficiency of particle collection by these methods, the data pairs demonstrate that micro-vacuum and wipe samples produced statistically equivalent results, with micro-vacuum samples being more efficient on the rough surface tested.

Global Magnitude of Reported and Unreported Mesothelioma

BackgroundLittle is known about the global magnitude of mesothelioma. In particular, many developing countries, including some with extensive historical use of asbestos, do not report mesothelioma.ObjectivesWe estimated the global magnitude of mesothelioma accounting for reported and unreported cases.MethodsFor all countries with available data on mesothelioma frequency and asbestos use (n = 56), we calculated the 15-year cumulative number of mesotheliomas during 1994–2008 from data available for fewer years and assessed its relationship with levels of cumulative asbestos use during 1920–1970. We used this relationship to predict the number of unreported mesotheliomas in countries for which no information on mesothelioma is available but which have recorded asbestos use (n = 33).ResultsWithin the group of 56 countries with data on mesothelioma occurrence and asbestos use, the 15-year cumulative number of mesothelioma was approximately 174,300. There was a statistically significant positive linear relation between the log-transformed national cumulative mesothelioma numbers and the log-transformed cumulative asbestos use (adjusted R2 = 0.83, p < 0.0001). Extrapolated to the group of 33 countries without reported mesothelioma, a total of approximately 38,900 (95% confidence interval, 36,700–41,100) mesothelioma cases were estimated to have occurred in the 15-year period (1994–2008).ConclusionsWe estimate conservatively that, globally, one mesothelioma case has been overlooked for every four to five reported cases. Because our estimation is based on asbestos use until 1970, the many countries that increased asbestos use since then should anticipate a higher disease burden in the immediate decades ahead.