Exposure Of Miners Research Articles

Applicability of aethalometers for monitoring diesel particulate matter concentrations and exposure in underground mines

Occupational exposure to diesel exhaust is regulated by legislation in Europe owing to its carcinogenic effects on humans. In underground mines, exposure to diesel exhaust requires regular monitoring. In this work, we investigate the usage of aethalometer AE33 and portable micro-aethalometer MA200 to assess occupational exposure to diesel exhaust in two underground mines. These instruments provide continuous data on wavelength-dependent particle light absorption, and based on this, equivalent black carbon (eBC) particle concentrations and potential sources. Both aethalometers correlated well with the thermal-optical elemental carbon analysis. Time-resolved aethalometer data revealed work-activity-dependent eBC concentration patterns that can be beneficial for identifying work phases that are significant for occupational exposure. In particular, high eBC peak exposures were observed for workers near load haul dumping areas. The diesel soot mass absorption cross-sections determined were similar for both mines. The absorption Ångström exponent determined from the aethalometer data was suitable for detecting and assessing the contributions of other potential sources to eBC concentrations, such as tobacco smoke, which is often prevalent in work environments. Overall, the portable micro-aethalometers proved to be suitable for monitoring occupational diesel exhaust exposure and can be useful for designing targeted exposure prevention measures in mining environments.

Risk assessment for conventional diesel exhaust (before 1990) and lung cancer in a cohort of miners.

Diesel exhaust in the latter half of the 20th century has been found to be a lung carcinogen. Conventional diesel emissions continue in the transportation, mining, construction, and farming industries. From the Diesel Exhaust in Miners Study, a public-use dataset was used to calculate the excess lifetime risk of lung cancer associated with diesel exposure (1947-1997). Excess rates of lung cancer mortality associated with respirable elemental carbon (REC) and possible other mining exposures (e.g., oil mists, explosives emissions) were investigated using Poisson regression methods. Lung cancer mortality declined with increasing employment duration while increasing with cumulative REC and non-diesel exposures, suggesting a strong worker survivor effect. Attenuation of the REC effect was observed with increasing cumulative exposure. After adjustment for employment duration, the excess rate ratio for lung cancer mortality was 0.67 (95% CI=0.35-0.99) for a 10-year lagged exposure to 200μg/m3 REC, a typical below-ground exposure in the study mines. At exposures of 200, 10, and 1μg/m3 REC, the estimated excess lifetime risks, respectively, were 119, 43, and 8.7 per thousand. Analysis of an inception cohort hired after dieselization commenced produced smaller and less certain estimates of lifetime risk. From exposures to conventional diesel engine exhaust common in occupational groups in the past, the excess lifetime risk of lung cancer was more than 5%. Ambient REC exposures in the general population were estimated to confer lifetime risks of 0.14 to 14 per thousand, depending on assumptions made.

A current affair: worker perceptions of noise exposure and occupational hearing loss in Australian coal mines.

The objective of the online survey was to determine worker attitudes towards, perceptions on hearing loss, and management of workplace noise; and to identify barriers within current strategies that prevent effective management of hearing health in Australian mines. This cross-sectional study utilized a modified survey design, initially designed for use by Safe Work Australia for a broader study published in 2010. The survey questionnaire was made available online to volunteer participants, recruited with the assistance of State and National Health and Safety, and mining organizations. Volunteer participants were required to be proficient in English, be employed by an Australian underground or open cut mine, including coal processing plants; or work as a contractor on one of the specified mine sites. All mining employees, regardless of occupation, job title, and occupational hearing loss classification or status, were invited to complete the questionnaire. Almost 60% of respondents indicated that they had high noise exposure for than 10 yr or more, and have some trouble hearing, mostly associated with infrequent tinnitus. Nearly 71% of these workers believe that the noise control strategies in their workplaces are effective, but this mostly refers to the use of hearing protection devices. The results indicate that general knowledge on the cause and effect of noise exposure in the workplace is well understood. However, due to the long latency associated with the development of noise-induced hearing loss (NIHL), there is an issue urgency in terms of risk management. It is surprising that most of the respondents recommended more inspections and administrative controls, especially since most respondents were health, safety, and environment (HSE) professionals. HSE professionals should be advocating for higher order, more permanent solutions, and not purely administrative controls and personal protective equipment. These findings raise the question of whether there is a multifaceted working-culture issue that needs to be addressed, in combination with higher order control implementation.

Occupational health risk assessment of silicosis caused by silica dust exposure in non-ferrous metal mines in 7 provinces from 2019 to 2020

To explore the occupational health risk level of silicosis caused by silica dust exposure in non-ferrous metal mining enterprises. Using typical sampling method, 44 non-ferrous metal mining enterprises were selected in seven provinces.37 non-ferrous metal mining enterprises were included, and most of them were underground enterprises(97.30%). Enterprises basic information and silica dust exposure data of key positions were collected by using on-site hygiene investigation and detecting method. Finally, the International Council on Mining and Metals'(ICMM) risk rating table method and occupational hazard risk index method(INDEX) were used to analyze the occupational health risk level of silicosis caused by silica dust exposure in non-ferrous metal mines from total and respirable dust views, respectively. Meanwhile, the square weighted Kappa test was performed to analyze the consistency between two risk assessment method. Medium enterprises(64.69%(40.38%, 73.41%)), silver mining enterprises(84.69%(63.38%, 86.06%)) and antimony mining enterprises(72.22%) had relatively higher silica dust exposure rates. On-site hygiene detecting result showed that:(1) M(P25, P75) of free silica content was 21.18%(17.03%, 30.47%). (2) 1.60(0.86, 2.46)mg/m~3 for total dust concentration, 64.47% total dust concentration samples exceeding Chinese permissible concentration-time weighted average(PC-TWA), 0.68(0.30, 1.18) mg/m~3 for respiratory dust concentration, 50.00% respirable dust concentration samples exceeding Chinese PC-TWA. (3) Medium-sized enterprises, as well as rock drillers and crushers, had higher levels of silica dust exposure. Occupational health risk assessment result showed that:(1) The overall occupational health risk level of silicosis caused by silica dust exposure in non-ferrous metal mining enterprises was medium:(1) In term of total dust, ICMM risk rating table method and INDEX method indicated high and medium risks, respectively(S_(weighted) were 3.52 and 2.79). (2) In term of respirable dust, both ICMM risk rating table and INDEX method indicated medium risks(S_(weighted) were 2.78 and 2.35). (2) Medium-sized enterprises risk level was higher than other two production scales enterprises. ICMM risk rating table method and the INDEX method consistency analyses showed that these two risk assessment method had strong consistencies in terms of total dust or respirable dust(both Kappa values ≥ 0.600). The overall occupational health risk level of silicosis caused by silica dust exposure in non-ferrous metal mining enterprises was medium, and the risk levels of medium production-scale mining enterprises, rock driller and crusher were higher.

Radon in Finnish underground mines 2011–2019

Radon measurements in Finnish underground mines were started in 1972. Since 1992, regular radon inspections by the competent authority have been carried out in all underground mines. During these inspections, several grab samples are taken from the air, which are later measured in the laboratory. This is a follow-up survey of radon concentrations in the air of the underground mines. The average radon concentrations in the mines between the years 2011 and 2019 varied from 90 to 1100 Bq m−3. Overall, the occupational radon exposure in the Finnish underground mines has remained at a low level from the 1990s onwards. In recent years, high radon concentrations have been observed only in those mines where active mining has ceased. Compared to other recent studies in mines in other countries, radon concentrations in Finnish mines are approximately at the same level. Uncertainties relating to infrequent grab sampling have been recognised and the authority is now testing personal radon detectors that may be used for the exposure assessment in the future.

RADON IN MINES OF KRYVYI RIH IRON ORE BASIN IN UKRAINE.

The first studies of radiation exposure in old mines of Kryvyi Rih Iron Ore Basin (Kryvbas) began relatively recently, about 20years ago. The results of these studies have shown that the problem of radon is present in the major part of the Basin mines. In 6 of 8 mines tested, an excess of radiation safety standards for the equilibrium equivalent decay products concentration (EEC) of Radon-222 was observed. According to the sum of the main measured parameters of radiation situation, a preliminary assessment of doses to underground workers was made and a classification of the Basin mines according to radiation danger was developed. Results of the recent radiation surveys of these mines are shown in this article. Data on the incidence of lung cancer among the miners are presented and classified into age groups. Measures to improve the radiation situation in the mines of Kryvbas are considered.

Occupational exposure in lead and zinc mines induces oxidative stress in miners lymphocytes: Role of mitochondrial/lysosomal damage

Abstract The purpose of this research was to determine mitochondrial and lysosomal damage and oxidative stress status in blood lymphocytes of lead-zinc miners. This research was performed in 10 mine workers who have been in contact with lead and zinc in comparison to a control group containing 10 healthy volunteers. Lymphocytes were isolated from peripheral blood using the Ficoll standard method and then mitochondrial and lysosomal damage and oxidative stress were evaluated. The level of reactive oxygen species (ROS), collapse in the mitochondrial membrane potential (MMP) collapse, and glutathione disulfide (GSSG) content, and lysosomal damage in miners were higher than the control group. Also, viability and glutathione (GSH) content were decreased. The lymphocytes of workers of a lead-zinc mine are more susceptible to oxidative stress, mitochondrial and lysosomal damage. The proper use of safety equipment can reduce the risk of toxic agents and their subsequent hazards for mine workers.

Analysis of Historical Worker Exposures to Respirable Dust from Talc Mining and Milling Operations in Vermont.

Talc is mined and milled throughout the world for use in a variety of industrial and consumer products. Although prior studies have evaluated workplace exposures or health effects from talc operations, the primary emphasis of these investigations has been on certain mineral contaminants (e.g. crystalline silica and asbestos) rather than talc itself. The purpose of this analysis is to evaluate historical worker exposures to respirable dust (as a measure of talc exposures) in the Vermont talc mines and mills, which involved a relatively pure form of talc (i.e. no asbestos and <0.25% or <1% crystalline silica). Respirable dust sampling data collected for workers in the Vermont mines and mills, which have not been previously published, were obtained from both mining company records and Mine Safety and Health Administration (MSHA) inspections. Because of differences in sampling design, the company and MSHA data were analyzed and reported separately. Overall, nearly 700 respirable dust samples collected for 44 job categories at 7 site locations over an approximate 30-year period were analyzed. Average respirable dust concentrations were found to exceed occupational exposure limits (OELs) in the United States and other countries for several job categories and site locations. Regardless of data source, the highest observed exposures were for mining jobs involving the operation of heavy equipment to break up, move, or load raw ore from the mines and milling or shipping jobs involving the crushing of raw ore, cleaning and drying of processed talc, and bagging and packaging of the final talc product. When analyzing the company data, the arithmetic mean respirable dust concentration was 2.73 mg m-3 for Muckerman at Hammondsville Mine, 3.18 mg m-3 for dosco operator at Ludlow mines, 1.35 mg m-3 for crusher operator at Gassetts Mill, 2.4 mg m-3 for palletizer at West Windsor Mill, and 2.68 mg m-3 for bagging operator at Columbia Shipping Center. When analyzing the MSHA data, the arithmetic mean respirable dust concentration was 3.5 mg m-3 for kiln/dryer operator at Hammondsville Mine, 1.27 mg m-3 for driller at Ludlow mines, 3.69 mg m-3 for ball mill operator at Columbia mill, 3.02 mg m-3 for flotation operator at West Windsor Mill, and 3.24 mg m-3 for bagging operator at Columbia Shipping Center. Worker exposures were found to decline over time for many, but not all, jobs. Our findings highlight potential high-risk jobs that might benefit from additional exposure control strategies at current or future talc manufacturing sites. The respirable dust measurements summarized here may also be used to reconstruct historical worker exposures at the Vermont sites or aid in subsequent epidemiology studies of this cohort focused on malignant or non-malignant respiratory disease.

Enviromental Health Risk Assessment of Diesel Particulate Matter (DPM) in Underground Mining

Workers underground mines are at risk of Diesel Particulate Matter (DPM) exposure. Exposure from DPM is one of the problems that can be found in underground mines. DPM has both carcinogenic effects and non-carcinogenic effects on humans. Due to the effects of DPM exposure, especially non-carcinogenic impacts, it is necessary to assess the risk of DPM exposure in underground mines. The Environmental Health Risk Analysis is an assessment of the health risks that can occur at any time in a population at risk. EHRA will generate quantitative risk characteristics, risk management options and communication strategies that will be applied to minimize the risk from DPM exposure. This study was conducted by looking at DPM measurement data in 4 underground mine, then calculated quantitatively by using default. Results from DPM measurements in 4 underground mines showed that DPM levels in all underground mines exceeded the threshold value of 160 μg/m3, while the mean of all DPM measurements in the underground mine is 0.374 μg/m3. To determine whether there are non-carcinogenic effects in DPM exposure, it can be seen by calculating RQ (Risk Quotient). The conclusion of this study indicate that in all underground mines having RQ&gt; 1 then there is a need for risk management. In the implementation of risk management there are several ways, reduce the concentration of exposure (Csafe) and reduce exposure time. Risk communication by performing the role of each relevant part from stakeholders to workers exposed to DPM.

Empirical engineering models for airborne respirable dust capture from water sprays and wet scrubbers.

Airborne respirable coal dust capture by water sprays or wet scrubbers has been studied and developed over many decades as an engineering control to reduce dust exposure in coal mines and combat coal worker pneumoconiosis. Empirical relationships and deterministic models for particular dust capture experiments have previously been devised to show the key parameters involved in airborne coal dust capture. Many of the results from these models show that the significant parameters related to airborne dust capture are water spray pressure, water quantity, water droplet size, relative water droplet-to-dust particle velocity, and total operating air pressure of the scrubber. However, many airborne dust capture efficiency relationships and models developed for particular experiments cannot be readily applied to forecast the dust collection efficiency of different spray and scrubber design configurations, which rely on several key dimensional engineering measures. This study examines engineering measures from previous water spray and wet scrubber experiments conducted by the U.S. National Institute for Occupational Safety and Health (NIOSH) and the U.S. Bureau of Mines (USBM) to develop empirical models for wet collection of airborne dusts. A dimensionless empirical model developed for predicting airborne dust capture efficiency of water sprays and wet scrubbers is presented.

Diesel engine exhaust exposure in underground mines: Comparison between different surrogates of particulate exposure

ABSTRACTExposure to diesel particulate matter (DPM) is frequently assessed by measuring indicators of carbon speciation, but these measurements may be affected by organic carbon (OC) interference. Furthermore, there are still questions regarding the reliability of direct-reading instruments (DRI) for measuring DPM, since these instruments are not specific and may be interfered by other aerosol sources. This study aimed to assess DPM exposure in 2 underground mines by filter-based methods and DRI and to assess the relationship between the measures of elemental carbon (EC) and the DRI to verify the association of these instruments to DPM. Filter-based methods of respirable combustible dust (RCD), EC, and total carbon (TC) were used to measure levels of personal and ambient DPM. For ambient measurements, DRI were used to monitor particle number concentration (PNC; PTrak), particle mass concentration (DustTrak DRX and DustTrak 8520), and the submicron fraction of EC (EC1;Airtec). The association between ambient EC and the DRI was assessed by Spearman correlation. Geometric mean concentrations of RCD, respirable TC (TCR) and respirable elemental EC (ECR) were 170 µg/m3, 148 µg/m3, and 83 µg/m3 for personal samples, and 197 µg/m3, 151 µg/m3, and 100 µg/m3 for ambient samples. Personal measurements had higher TCR:ECR ratios compared to ambient samples (1.8 vs. 1.50) and weaker association between ECR and TCR. Among the DRI, the measures of EC1 by the Airtec (ρ = 0.86; P < 0.001) and the respirable particles by the DustTrak 8520 (ρ = 0.74; P < 0.001) showed the strongest association with EC, while PNC showed a weak and non-significant association with EC. In conclusion, this study provided important information about the concentrations of DPM in underground mines by measuring several indicators using filter-based methods and DRI. Among the DRI, the Airtec proved to be a good tool for estimating EC concentrations and, although the DustTrak showed good association with EC, interferences from other aerosol sources should be considered when using this instrument to assess DPM.

Transmission of ultrafine particles through separating systems of dust samplers

Abstract In underground mines there is a radiation hazard associated with natural radioactive nuclides. The main sources of radiation exposure in Polish mines are short-lived radon decay products, radioactive mine water containing radium and the sediments precipitated from these waters. For miners, the most common hazard is usually the short-lived radon decay products. Aspirators, equipped with separation systems, are mostly used in order to control this hazard. Inside these aspirators there are meters which measure the radiation emitted by radioactive aerosols collected on the filter. The purpose of these systems is to remove particles from the air stream that do not form the respirable fraction. At the same time, however, a deposition of small-size aerosols takes place in them because of the high values of their corresponding diffusion coefficients. This excludes the possibility of their proper detection by radiation meters. In this paper, the transmission of particles up to 100 nm in size by the separating systems is evaluated. The evaluated transmission ranged from about 60% for sizes of 7 nm, reaching up to 95% at the boundary values of the tested range. The influence of the particle distribution of the aerosols on the radiation calibration coefficients was also investigated in a radon chamber, through their exposure to conditions where the air contained low aerosol concentrations of about 4.0 × 108 particles/m3 and also when it was nearly 100-times higher. In the first case, the measured sensitivity of the meters was about 20–30% lower, which was probably due to a higher number of small aerosols and, as a result, particle transmission decreased. However, at higher aerosol concentrations, the sensitivity of the meters remained practically the same, regardless of whether the air reached the filters by the separation systems or if they were omitted.

Silica exposure in a mining exploration operation

ABSTRACTBackground: Though there is extensive research on occupational exposure in production mines, there is limited information on exposure during the exploration phase of mining.Methods: Air samples were collected in a core processing facility in Northern Ontario, Canada. All samples were analyzed for respirable dust (NIOSH 0600) and respirable crystalline silica (NIOSH 7602). Mean exposure levels were estimated and differences in exposure between work areas were investigated.Results: Sixteen personal and nine area air samples were collected. Respirable dust exposure ranged from < LOD to 2.24mg-m−3; respirable silica exposure ranged from < LOD to 0.055mg-m−3. Silica concentrations were higher among workers in the core cutting and core sorting (pulp and reject) areas, as compared to those in the core logging area.Conclusions: Workers employed in core processing facilities as part of mining exploration activities are exposed to respirable silica; exposure controls may be needed.

Radon concentration and gamma exposure in some Kosovo underground mines

Background : In this study are submied the radon concentraon m easurement results of four underground mines: Stanterg, Artana, Hajvali and Badovc, which are owned by Trepca Enterprise, Kosovo. The mines have the same geological formaon and from these mines are extracted ores rich with lead, zinc, silver, and gold. The radiaon exposures caused by radon and radon daughters was determined and gamma dose measurements were also performed in the sameme. Materials and Methods : The measurement of radon concentraons in the environment of mines is carried out by CRM 510, a portable device which connuously made measurement for four consecuve days. The gamma exposure was determined using fully portable handheld instrument GR-130 Exploranium. The detector consisted of a 65 cm 3 sodium iodide NaI(Tl) and a GM tube. The system was calibrated against a 137 Cs standard and checked for stability using a low-acvity 9 kBq radioacve source. Results: The radon gas concentraon for underground mines under study varied from minimal values 60 Bqm-3 to maximal recorded value 748 Bqm-3. The average radon concentraon for mines Stanterg, Artana, Hajvali and Badovc are 301.6, 191.4, 463.2 and 527.2 Bqm-3, respecvely. Conclusion: The average of total annual effecve doses from radon concentraon and radon decay products for miners under the study is 2.67 mSv and just from gamma ray exposure is 0.26 mSv. The average values for radon concentraon and radon decay products to mines under the study are lower than acon level 1000 Bq m-3 given by IAEA.

Noise and vibration: Mine workers’ exposure in Quebec underground mines

Noise and vibration: Mine workers’ exposure in Quebec underground mines

Comprehensive investigation of radon exposure in Austrian tourist mines and caves.

According to Austrian Law, dose assessments in workplaces with potentially enhanced radon exposures are mandatory since 2008, including tourist mines and caves. A pilot study was carried out to evaluate the situation to test the measurement methods and to specify the main parameters controlling the radon concentration in tourist mines and caves. Radon was measured in six mines and three caves for 1 y, along with determining thoron and equilibrium factors and taking into account climatic, geological and site-related effects. The radon concentrations have a seasonal dependence with maximum in summer and minimum in winter, related to natural ventilation. Radon concentrations in the karst caves were quite low, as it was in the salt mine, whereas radon concentrations in copper and silver mines were high. The dose assessment of the employees yielded doses above 6 mSv a(-1) only in the copper mine.

National radon programmes and policies: the RADPAR recommendations

Results from epidemiological studies on lung cancer and radon exposure in dwellings and mines led to a significant revision of recommendations and regulations of international organisations, such as WHO, IAEA, Nordic Countries, European Commission. Within the European project RADPAR, scientists from 18 institutions of 14 European countries worked together for 3 y (2009-12). Among other reports, a comprehensive booklet of recommendations was produced with the aim that they should be useful both for countries with a well-developed radon programme and for countries with little experience on radon issues. In this paper, the main RADPAR recommendations on radon programmes and policies are described and discussed. These recommendations should be very useful in preparing a national action plan, required by the recent Council Directive 2013/59/Euratom.

Assessment of occupational radiation exposure in underground artisanal gold mines in Tongo, Upper East Region of Ghana

Assessments of radon and gamma radiation levels were carried out in underground artisanal gold mines in Tongo. This is one of the numerous artisanal gold mining communities in Ghana. Solid State Nuclear Track Detectors (SSNTDs) were used to estimate the mean 222Rn concentration and dose rates during the Harmattan season (November 2010 to February 2011). The values for the 222Rn concentration at each monitoring site ranged from 14 ± 4 Bq m−3 to 270 ± 9 Bq m−3, with a mean value of 98 Bq m−3. These measurements are well below the lower action level of 500 Bq m−3 recommended by ICRP for workplaces. The activity concentrations of 40K, 232Th and 238U were determined using gamma-ray spectroscopy method. The effective dose estimates of 0.11 ± 0.02 mSv y−1 to 0.68 ± 0.04 mSv y−1 were below the allowable limit of 20 mSv per annum for occupational exposure control recommended by the ICRP. The total annual effective dose varied from 0.22 ± 0.04 mSv y−1 to 1.92 ± 0.08 mSv y−1.

INFLUENCE OF OBESITY ON SPIROMETRIC PARAMETERS IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE

Harmful air particles emissions (heavy industry, thermal and nuclear power plants, vehicles that burn fissile fuel, professional exposure in factories and mines, consumption of cigarettes), greatly disturb the function of the respiratory system. Obesity is associated with chronic low-grade inflammation and increased numbers of activated macrophages in adipose tissue. Adipose tissue provides an abundance of inflammatory mediators, suggesting a possible link between obesity and immunological developments in COPD. The aim of the paper was to determine whether obesity has a significant effect on spirometric parameters in patients with COPD, and to determine whether weight loss caused by reduction of adipose tissue has a positive effect on improvement of spirometric parameters in patients with COPD. The study included 190 examinees aged 35 to 65 years, of both sexes, divided into four groups: the first group recruited 40 examinees with different degrees of obesity and without verified COPD, 20 persons (group 1a) with obesity from I (BMI 30-35) to III (BMI>40) and 20 subjects (group 1b) with pre-obesity (BMI 25-30); the second group included 50 examinees who had normal nutritional status and COPD with different duration; the third group consisted of 50 examinees, who had I degree obesity (BMI 3035) and COPD; the fourth group consisted of 50 examinees, who had II degree obesity (BMI of 35-40) and COPD with different duration. The research lasted three years, covering the period from 2007 to 2010. The subjects were being examineed for 180 days, and all the changes related to spirometry parameters and body mass index (BMI) were followed up. Comparing the average measures and standard deviations in FEV1/ FVC between groups 4 (66,71±4,53), 2 (69,1±5,98) and 3 (70,69±5,81), there were no significant statistical differences. The values of spirometric parameters between two groups of patients with COPD were compared. The first group of patients involved subjects who in the period of 180 days had weight loss greater than 10% and second (2) group in which subjects had no significant weight loss. It was found that respondents from the first group had a statistically significant increase in the observed values of all spirometric parameters compared to another group. FVC: 4.33(1) 0.99(2); p<0, 01. FEV1: 7.38(1) 2.67(2); p<0.01. FEV1/FVC: 4,27(1) 2,14(2); p<0,05. Obesity has no significant effect on spirometric parameters in patients with COPD. Losing weight in favor of adipose tissue reducing has a significant effect on improving the spirometric parameters in patients with COPD. Acta Medica Medianae 2011; 50(4): 11-16.

The Influence of Dust Standards on the Prevalence and Severity of Coal Worker's Pneumoconiosis at Autopsy in the United States of America

Coal worker's pneumoconiosis is a major occupational lung disease in the United States. The disease is primarily controlled through reducing dust exposure in coal mines using technological improvements and through the establishment of dust standards by regulatory means. To determine if dust standards established in the US Federal Coal Mine Health and Safety Act of 1969 have reduced the prevalence and severity of coal worker's pneumoconiosis. The study population included materials from 6103 deceased coal miners submitted to the National Coal Workers' Autopsy Study from 1971 through 1996. Type and severity of coal worker's pneumoconiosis were classified using standardized diagnostic criteria. Among miners who worked exclusively prior to the 1969 dust standard, 82.6% had coal macules, 46.3% coal nodules, 28.2% silicotic nodules, and 10.3% progressive massive fibrosis. Lower prevalences were noted among miners exposed exclusively to post-1970 dust levels: 58.8% had coal macules, 15.0% coal nodules, 8.0% silicotic nodules, and 1.2% progressive massive fibrosis. The differences in prevalence were highly significant (P < .001) for all types of pneumoconiosis, including progressive massive fibrosis, after adjustment for age, years of mining, and smoking status. The study confirms a beneficial impact of the first 25 years of the dust standard established by the 1969 act on the prevalence and severity of coal worker's pneumoconiosis in US coal miners. However, pneumoconiosis continues to occur among miners who have worked entirely within the contemporary standard, suggesting a need for further reductions in exposure to respirable coal mine dust.