Acute occupational inhalation injuries-United States, 2011-2022.

BACKGROUND: Inhalation injuries due to acute occupational exposures to chemicals are preventable. National surveillance of acute inhalation exposures is limited. This study identified the most common acute inhalation exposure-related incidents by industry sector among US workers. METHODS: To characterize inhalation-related injuries and their exposures during April 2011-March 2022, state and federal records from the Occupational Safety and Health Administration (OSHA) Occupational Safety and Health Information System (OIS) accident database were analyzed. Industry-specific injury, hospitalization, and fatality rates were calculated. RESULTS: The most frequent acute inhalation incidents investigated by OSHA were caused by inorganic gases (52.9%) such as carbon monoxide (CO) or acids, bases, and oxidizing chemical agents (12.9%) such as anhydrous ammonia. The largest number of fatal and nonfatal injuries were reported in the manufacturing (28.6%) and construction (17.2%) sectors. CONCLUSIONS: Workers were affected by acute inhalation exposures in most industries. Using this surveillance, employers can recognize frequently-occurring preventable acute inhalation exposures by industry, such as inorganic gases in the manufacturing sector, and implement prevention measures. Training of workers on exposure characteristics and limits, adverse health effects, and use of protective equipment by exposure agent can prevent inhalation injuries.

Estimation of the number of workers exposed to respirable crystalline silica by industry: Analysis of OSHA compliance data (1979-2015).

BACKGROUND: Respirable crystalline silica (RCS) can potentially cause silicosis, lung cancer, and renal failure. The current study estimates the percentages of workers potentially overexposed to concentrations of RCS dust and silicosis proportional mortality rates (PMRs) by industry. METHODS: Occupational Safety and Health Administration compliance inspection sampling data for RCS collected during 1979 to 2015 were used to estimate percentages of workers exposed. The results were used in combination with US Census Bureau estimates to produce industry specific worker population estimates for 2014. Estimates of the numbers and percentages of workers exposed to RCS concentrations at least 1, 2, 5, and 10 times the National Institute for Occupational Safety and Health recommended exposure limit (REL) were calculated by industry using the 2002 North American Industry Classification System. Silicosis PMRs by industry were estimated using National Center for Health Statistics multiple cause of death data. RESULTS: RCS concentrations/workers exposed were highest in the poured concrete foundation and structure contractors; commercial and institutional building construction; and masonry contractors. Approximately 100 000 workers were exposed above the RCS REL, and most (79%) worked in the construction industry. Tile and terrazzo contractors (12%); brick, stone, and related construction merchant wholesalers (10%); masonry contractors (6%) and poured concrete foundation and structure contractors (6%) were the highest percentages of workers potentially overexposed. PMRs were highest for the structural clay product manufacturing and the foundries industries. CONCLUSION: Percentages of workers exposed to RCS varied by industry and in some industries workers are exposed over 10 times the REL. Exposures can be reduced below the REL by implementing the hierarchy of controls.

Respirable coal mine dust at surface mines, United States, 1982-2017.

BACKGROUND: Exposure to respirable coal mine dust can cause pneumoconiosis, an irreversible lung disease that can be debilitating. The mass concentration and quartz mass percent of respirable coal mine dust samples (annually, by occupation, by geographic region) from surface coal mines and surface facilities at U.S. underground mines during 1982-2017 were summarized. METHODS: Mine Safety and Health Administration (MSHA) collected and analyzed data for respirable dust and a subset of the samples were analyzed for quartz content. We calculated the respirable dust and quartz concentration geometric mean, arithmetic mean, and percent of samples exceeding the respirable dust permissible exposure limit (PEL) of 2.0 mg/m3, and the average percent of quartz content in samples. RESULTS: The geometric mean for 288 705 respirable dust samples was 0.17 mg/m3 with 1.6% of the samples exceeding the 2.0 mg/m3 PEL. Occupation-specific geometric means for respirable dust in active mining areas were highest among drillers. The geometric mean for respirable dust was higher in central Appalachia compared to the rest of the U.S. The geometric mean for respirable quartz including 54 040 samples was 0.02 mg/m3 with 15.3% of these samples exceeding the applicable standard (PEL or reduced PEL). Occupation-specific geometric means for respirable quartz were highest among drillers. CONCLUSION: Higher concentrations of respirable dust or quartz in specific coal mining occupations, notably drilling occupations, and in certain U.S. regions, underscores the need for continued surveillance to identify workers at higher risk for pneumoconiosis.

Respirable coal mine dust in underground mines, United States, 1982-2017.

BACKGROUND: This study summarized the mass concentration and quartz mass percent of respirable coal mine dust samples (annually, by district, and by occupation) from underground coal mines during 1982-2017. METHODS: Respirable dust and quartz data collected and analyzed by Mine Safety and Health Administration (MSHA) were summarized by year, coal mining occupation, and geographical area. The older (before August 2016) 2.0 mg/m 3 respirable dust MSHA permissible exposure limit (PEL) was used across all years for comparative purposes. For respirable dust and quartz, geometric mean and percent of samples exceeding the respirable dust PEL (2.0 mg/m 3 or a reduced standard for samples with >5% quartz content) were calculated. For quartz samples, the average percent quartz content was also calculated. RESULTS: The overall geometric mean concentration for 681 497 respirable dust samples was 0.55 mg/m 3 and 5.5% of the samples exceeded the 2.0 mg/m 3 PEL. The overall respirable quartz geometric mean concentration for 210 944 samples was 0.038 mg/m 3 and 18.7% of these samples exceeded the applicable standard. There was a decline over time in the percent of respirable dust samples exceeding 2.0 mg/m 3 . The respirable dust geometric mean concentration was lower in central Appalachia compared to the rest of the United States. However, the respirable quartz geometric mean concentration and the mean percent quartz content were higher in central Appalachia. CONCLUSION: This study summarizes respirable dust and quartz concentrations from coal mine inspector samples and may provide an insight into differences in the prevalence of pneumoconiosis by region and occupation.

Potential determinants of coal workers' pneumoconiosis, advanced pneumoconiosis, and progressive massive fibrosis among underground coal miners in the United States, 2005-2009.

OBJECTIVES: We better defined the distribution and determinants of coal workers' pneumoconiosis (CWP) among US underground coal miners. METHODS: We obtained chest radiographs from the mobile unit of an enhanced surveillance program begun in 2005 by the National Institute for Occupational Safety and Health for underground coal miners. B Readers classified them for presence of pneumoconiosis. RESULTS: Miners from 15 states participated (n = 6658). The prevalence of CWP was higher in 3 states (Kentucky, 9.0%; Virginia, 8.0%; West Virginia, 4.8%) than in 12 other states (age-adjusted risk ratio [RR] = 4.5; 95% confidence interval [CI] = 3.3, 6.1). Miners in these 3 states were younger and had less mining tenure, but advanced CWP (category ≥ 2/1; RR = 8.1; 95% CI = 3.9, 16.9) and progressive massive fibrosis (RR = 10.5; 95% CI = 3.8, 29.1) was more prevalent among them. Advanced CWP and progressive massive fibrosis were more prevalent among workers at mines with fewer than 155 miners, irrespective of mining region, than among workers at larger mines. CONCLUSIONS: Enhanced surveillance results confirmed the persistence of severe CWP among US coal miners and documented the health consequences of inadequate dust control for miners in parts of Appalachia and at smaller mines.

Coal workers' pneumoconiosis in the United States: regional differences 40 years after implementation of the 1969 Federal Coal Mine Health and Safety Act.

OBJECTIVE: To assess whether the recent increases in the prevalence of coal workers' pneumoconiosis (CWP) in the USA reflect increased measured exposures over recent decades, and to identify other potential causative factors. METHODS: The observed CWP prevalence was calculated for 12,408 underground coal miner participants in the Coal Workers' Health Surveillance Program for the period 2005-2009, stratified by the Mine Safety and Health Administration (MSHA) geographical districts. The predicted prevalence was estimated using a published exposure-response model from a large epidemiological study among U.S. coal miners using dust exposure, tenure, miner's age and coal rank as predictors. χ2 Testing was performed to compare the observed versus predicted CWP prevalence. RESULTS: Observed prevalence was significantly higher than predicted prevalence in MSHA districts 4-7 (central Appalachian region) (10.1% vs. 4.2%; prevalence ratio (PR) 2.4; p<0.001) and significantly lower than predicted in other regions (1.6% vs. 3.6%; PR 0.4; p<0.001). The central Appalachian region had a significantly older workforce with greater mining tenure, a lower proportion of mines with 200 or more employees, and lower seam heights. Significant lower average compliance dust concentrations were reported for this region. CONCLUSION: The observed CWP prevalence substantially exceeded predicted levels in central Appalachia. However, the increased prevalence was not explained by the measured levels of dust exposures. Likely contributing factors include mine size and low seam mining, which may be associated with higher exposure to silica. Further study is needed to characterise the responsible factors for the elevated CWP rates in central Appalachia.

The National Institute for Occupational Safety and Health B Reader Certification Program-An Update Report (1987 to 2018) and Future Directions.

OBJECTIVE: The National Institute for Occupational Safety and Health (NIOSH) B Reader Program provides the opportunity for physicians to demonstrate proficiency in the International Labour Office (ILO) system for classifying radiographs of pneumoconioses. We summarize trends in participation and examinee attributes and performance during 1987 to 2018. METHODS: Since 1987, NIOSH has maintained details of examinees and examinations. Attributes of examinees and their examination performance were summarized. Simple linear regression was used in trend analysis of passing rates over time. RESULTS: The mean passing rate for certification and recertification for the study period was 40.4% and 82.6%, respectively. Since the mid-1990s, the number of B Readers has declined and the mean age and years certified have increased. CONCLUSIONS: To address the declining B Reader population, NIOSH is currently taking steps to modernize the program and offer more opportunities for training and testing.

Radiographic features of importance in the National Institute for Occupational Safety and Health-administered Coal Workers' Health Surveillance Program: characterising the use of the 'other symbols'.

OBJECTIVE: The National Institute for Occupation Safety and Health-administered Coal Workers' Health Surveillance Program (CWHSP) provides radiographic pneumoconiosis screening for US coal miners. Radiographs are classified by readers according to International Labour Office criteria. In addition to pneumoconiotic parenchymal and pleural lung abnormalities, readers document radiographic features of importance (other symbols). Other symbols are not meant to imply a diagnosis or interpretation but are relevant as they provide information beyond a pneumoconiosis classification for features related to dust exposure and other aetiologies. Our objective was to summarise other symbol data from 48 years of CWHSP participants. METHODS: Chest radiograph classifications obtained from CWHSP participants between July 1968 and July 2016 were analysed. Any 'other symbol' indication from any of the readings were counted. Frequencies were tabulated by individual reader and those identified by any reader. RESULTS: Of the 469 922 radiographs included in this study, nearly 15% had at least one reader identify a radiographic feature of importance. The most commonly identified other symbol was cancer (excluding mesothelioma) (6.83%), followed by emphysema (1.68%). Some features were rarely identified over the 48 years of data collection such as rheumatoid pneumoconiosis (n=46), pneumothorax (n=32), mesothelioma (n=12) and rounded atelectasis (n=4). CONCLUSIONS: This is the largest study to date describing radiographic features of importance as part of routine chest radiographic surveillance. While these symbols are not diagnostic they can be used to describe features associated with dust exposure. One of the most commonly identified radiographic features in our population is emphysema which is associated with respirable dust exposure. These results can be compared with other dust exposed populations.