Assessment of the Respiratory Health of Working US Coal Miners Since 2014-Radiography, Spirometry, and Symptom Assessments.

OBJECTIVE: The aim of the study is to summarize Coal Workers' Health Surveillance Program findings since 2014, focusing on prevalence of radiographic pneumoconiosis and abnormal spirometry by region. METHODS: Analysis included the most recent Coal Workers' Health Surveillance Program encounter for working miners during October 1, 2014-June 30, 2022. Central Appalachia consists of Kentucky, Virginia, and West Virginia. RESULTS: Pneumoconiosis prevalence was highest among underground miners, with 318 (6.2%) having radiographic evidence of disease. Central Appalachian miners were more likely to have evidence of pneumoconiosis (relative risk = 4.1 [3.4-5.0]) and abnormal spirometry (relative risk = 1.4 [1.2-1.6]) compared with all others. CONCLUSIONS: Central Appalachia is a hotspot for pneumoconiosis, as well as for other indicators of respiratory impairment in coal miners. Outreach for occupational respiratory health surveillance should focus on those areas most heavily affected, ensuring that miners are not hindered by perceived or actual barriers to this secondary intervention.

Submission of mandatory respiratory health examinations among US coal miners participating in the Coal Workers' Health Surveillance Program.

BACKGROUND: Mandatory examination requirements for US coal miners newly entering the workforce have been in place since the 1969 Coal Act mandated chest radiographs and were updated to include spirometry with promulgation of the 2014 Mine Safety and Health Administration Dust Rule. Compliance with the mandatory respiratory screening series is described using data from the National Institute for Occupational Safety and Health Coal Workers' Health Surveillance Program (CWHSP). METHODS: Among all radiographic and spirometry submissions to the CWHSP during 30 June 1971-15 March 2022, new underground coal miners who began work in the industry after 30 June 1971, and new underground, surface miners and contractors who began work after new regulations were implemented 1 August 2014, were identified and included in analysis. RESULTS: Of the 115 093 unique miners who participated in the CWHSP and whose estimated entry into mining occurred during 30 June 1971-15 March 2019, 50 487 (43.9%) received their initial mandatory radiograph, and 15 452 (13.4%) submitted their initial and 3-year mandatory radiographs. Since new regulations were implemented, compliance with initial radiographs appeared to improve (80%) but compliance with 3-year radiographs remained low (11.6%). Compliance with spirometry testing was also low for initial (17.1%) and follow-up screenings (2.7%). CONCLUSIONS: The majority of new coal miners eligible for health surveillance did not receive a baseline radiograph or spirometry test through the CWHSP even though coal mine operators are required by law to provide these. Ensuring coal miners' regular participation in health surveillance from early in their careers is an important way to monitor and protect their respiratory health.

Paid Sick Leave Among U.S. Healthcare Personnel, April 2022.

INTRODUCTION: Healthcare personnel are at risk for acquiring and transmitting respiratory infections in the workplace. Paid sick leave benefits allow workers to stay home and visit a healthcare provider when ill. The objectives of this study were to quantify the percentage of healthcare personnel reporting paid sick leave, identify differences across occupations and settings, and determine the factors associated with having paid sick leave. METHODS: In a national nonprobability Internet panel survey of healthcare personnel in April 2022, respondents were asked, Does your employer offer paid sick leave? Responses were weighted to the U.S. healthcare personnel population by age, sex, race/ethnicity, work setting, and census region. The weighted percentage of healthcare personnel who reported paid sick leave was calculated by occupation, work setting, and type of employment. Using multivariable logistic regression, the factors associated with having paid sick leave were identified. RESULTS: In April 2022, 73.2% of 2,555 responding healthcare personnel reported having paid sick leave, similar to 2020 and 2021 estimates. The percentage of healthcare personnel reporting paid sick leave varied by occupation, ranging from 63.9% (assistants/aides) to 81.2% (nonclinical personnel). Female healthcare personnel and those working as licensed independent practitioners, in the Midwest, and in the South were less likely to report paid sick leave. CONCLUSIONS: Most healthcare personnel from all occupational groups and healthcare settings reported having paid sick leave. However, differences by sex, occupation, type of work arrangement, and Census region exist and highlight disparities. Increasing healthcare personnel's access to paid sick leave may decrease presenteeism and subsequent transmission of infectious diseases in healthcare settings.

Influenza and COVID-19 Vaccination Coverage Among Health Care Personnel - United States, 2021-22.

The Advisory Committee on Immunization Practices (ACIP) and CDC recommend that all health care personnel (HCP) receive annual influenza vaccination to reduce influenza-related morbidity and mortality among these personnel and their patients (1). ACIP also recommends that all persons aged ≥6 months, including HCP, be vaccinated with COVID-19 vaccines and remain up to date (2,3). During March 29-April 19, 2022, CDC conducted an opt-in Internet panel survey of 3,618 U.S. HCP to estimate influenza vaccination coverage during the 2021-22 influenza season as well as receipt of the primary COVID-19 vaccination series and a booster dose. Influenza vaccination coverage was 79.9% during the 2021-22 season, and 87.3% of HCP reported having completed the primary COVID-19 vaccination series; among these HCP, 67.1% reported receiving a COVID-19 booster dose. Among HCP, influenza, COVID-19 primary series, and COVID-19 booster dose vaccination coverage were lowest among assistants and aides, those working in long-term care (LTC) or home health care settings, and those whose employer neither required nor recommended the vaccines. Overall, employer requirements for influenza and COVID-19 primary series vaccines were reported by 43.9% and 59.9% of HCP, respectively; among HCP who completed the primary series of COVID-19 vaccines, 23.5% reported employer requirements for COVID-19 booster vaccines. Vaccination coverage for all three vaccine measures was higher among HCP who reported employer vaccination requirements and ranged from 95.8% to 97.3% for influenza, 90.2% to 95.1% for COVID-19 primary series, and 76.4% to 87.8% for COVID-19 booster vaccinations among HCP who completed the primary series of COVID-19 vaccines, by work setting. Implementing workplace strategies demonstrated to improve vaccination coverage among HCP, including vaccination requirements or active promotion of vaccination, can increase influenza and COVID-19 vaccination coverage among HCP and reduce influenza and COVID-19-related morbidity and mortality among HCP and their patients (4).

Postexposure progression of pneumoconiosis among former Appalachian coal miners.

BACKGROUND: The prevalence of pneumoconiosis among working United States underground coal miners has been increasing for the past two decades, with the highest rates of disease observed among miners in the central Appalachian states of Kentucky, Virginia, and West Virginia. Surveillance for this disease in the United States focuses on working coal miners, who continue to be occupationally exposed to dust. This study examines the radiographic evidence for postexposure progression of pneumoconiosis in a population of former coal miners no longer occupationally exposed to coal mine dust who were seen at a community radiology clinic in eastern Kentucky. METHODS: Data were obtained and analyzed from clinical records of former coal miners who had a clinic encounter during January 1, 2017-August 1, 2019, a recorded final year of employment, and ≥2 postemployment digital chest radiographs. Radiographs were classified according to the International Labour Office guidelines by at least two B Readers. A final summary pneumoconiosis severity score (range, 0-13), accounting for both small and large opacities, was assigned to each chest radiograph. Progression was defined as an increase in severity score between a miner's radiographs over time. RESULTS: Data for 130 former coal miners were analyzed. All miners were male and most (n = 114, 88%) had worked primarily in Kentucky. Information on race/ethnicity was not available. The most common job types were roof bolters (n = 51, 39%) and continuous miner operators (n = 46, 35%). Forty-one (31.5%) miners had evidence of radiographic disease progression after leaving the workforce, with a median of 3.6 years between first and latest postretirement radiograph. A total of 80 (62%) miners had evidence of pneumoconiosis on their latest radiograph, and two-thirds (n = 53) of these were classified as progressive massive fibrosis (PMF), the most severe form of the disease. CONCLUSIONS: Postexposure progression can occur in former coal miners, emphasizing the potential benefits of continued radiographic follow-up postemployment. In addition to participating in disease screening throughout their careers to detect pneumoconiosis early and facilitate intervention, radiographic follow-up of former coal miners can identify new or progressive radiographic findings even after workplace exposure to respirable coal mine dust ends. Identification of progressive pneumoconiosis in former miners has potential implications for clinical management and eligibility for disability compensation.

COVID-19 Vaccination and Intent Among Healthcare Personnel, U.S.

INTRODUCTION: Healthcare personnel are at increased risk for COVID-19 from workplace exposure. National estimates on COVID-19 vaccination coverage among healthcare personnel are limited. METHODS: Data from an opt-in Internet panel survey of 2,434 healthcare personnel, conducted on March 30, 2021-April 15, 2021, were analyzed to assess the receipt of ≥1 dose of a COVID-19 vaccine and vaccination intent. Multivariable logistic regression was used to assess the factors associated with COVID-19 vaccination and intent for vaccination. RESULTS: Overall, 68.2% of healthcare personnel reported a receipt of ≥1 dose of a COVID-19 vaccine, 9.8% would probably/definitely get vaccinated, 7.1% were unsure, and 14.9% would probably/definitely not get vaccinated. COVID-19 vaccination coverage was highest among physicians (89.0%), healthcare personnel working in hospitals (75.0%), and healthcare personnel of non-Hispanic White or other race (75.7%-77.4%). Healthcare personnel who received influenza vaccine in 2020-2021 (adjusted prevalence ratio=1.92) and those aged ≥60 years (adjusted prevalence ratio=1.37) were more likely to report a receipt of ≥1 dose of a COVID-19 vaccine. Non-Hispanic Black healthcare personnel (adjusted prevalence ratio=0.74), nurse practitioners/physician assistants (adjusted prevalence ratio=0.55), assistants/aides (adjusted prevalence ratio=0.73), and nonclinical healthcare personnel (adjusted prevalence ratio=0.79) were less likely to have received a COVID-19 vaccine. The common reasons for vaccination included protecting self (88.1%), family and friends (86.3%), and patients (69.2%) from COVID-19. The most common reason for nonvaccination was concern about side effects and safety of COVID-19 vaccine (59.7%). CONCLUSIONS: Understanding vaccination status and intent among healthcare personnel is important for addressing barriers to vaccination. Addressing concerns on side effects, safety, and effectiveness of COVID-19 vaccines as well as their fast development and approval may help improve vaccination coverage among healthcare personnel.

Characterization of Cleaning and Disinfection Product Use, Glove Use, and Skin Disorders by Healthcare Occupations in a Midwestern Healthcare Facility.

Healthcare facility staff use a wide variety of cleaning and disinfecting products during their daily operations, many of which are associated with respiratory or skin irritation or sensitization with repeated exposure. The objective of this study was to characterize the prevalence of cleaning and disinfection product use, glove use during cleaning and disinfection, and skin/allergy symptoms by occupation and identify the factors influencing glove use among the healthcare facility staff. A questionnaire was administered to the current employees at a midwestern Veterans Affairs healthcare facility that elicited information on cleaning and disinfection product use, glove use during cleaning and disinfection, skin/allergy symptoms, and other demographic characteristics, which were summarized by occupation. The central supply/environmental service workers (2% of the total survey population), nurses (26%,), nurse assistants (3%), and laboratory technicians (5%) had the highest prevalence of using cleaning or disinfecting products, specifically quaternary ammonium compounds, bleach, and alcohol. Glove use while using products was common in both patient care and non-patient care occupations. The factors associated with glove use included using bleach or quaternary ammonium compounds and using cleaning products 2-3 or 4-5 days per week. A high frequency of glove use (≥75%) was reported by workers in most occupations when using quaternary ammonium compounds or bleach. The use of alcohol, bleach, and quaternary ammonium compounds was associated with skin disorders (p < 0.05). These research findings indicate that although the workers from most occupations report a high frequency of glove use when using cleaning and disinfection products, there is room for improvement, especially among administrative, maintenance, and nursing workers. These groups may represent populations which could benefit from the implementation of workplace interventions and further training regarding the use of personal protective equipment and the potential health hazards of exposure to cleaning and disinfecting chemicals.

Outbreak of SARS-CoV-2 Infections, Including COVID-19 Vaccine Breakthrough Infections, Associated with Large Public Gatherings - Barnstable County, Massachusetts, July 2021.

During July 2021, 469 cases of COVID-19 associated with multiple summer events and large public gatherings in a town in Barnstable County, Massachusetts, were identified among Massachusetts residents; vaccination coverage among eligible Massachusetts residents was 69%. Approximately three quarters (346; 74%) of cases occurred in fully vaccinated persons (those who had completed a 2-dose course of mRNA vaccine [Pfizer-BioNTech or Moderna] or had received a single dose of Janssen [Johnson & Johnson] vaccine ≥14 days before exposure). Genomic sequencing of specimens from 133 patients identified the B.1.617.2 (Delta) variant of SARS-CoV-2, the virus that causes COVID-19, in 119 (89%) and the Delta AY.3 sublineage in one (1%). Overall, 274 (79%) vaccinated patients with breakthrough infection were symptomatic. Among five COVID-19 patients who were hospitalized, four were fully vaccinated; no deaths were reported. Real-time reverse transcription-polymerase chain reaction (RT-PCR) cycle threshold (Ct) values in specimens from 127 vaccinated persons with breakthrough cases were similar to those from 84 persons who were unvaccinated, not fully vaccinated, or whose vaccination status was unknown (median = 22.77 and 21.54, respectively). The Delta variant of SARS-CoV-2 is highly transmissible (1); vaccination is the most important strategy to prevent severe illness and death. On July 27, CDC recommended that all persons, including those who are fully vaccinated, should wear masks in indoor public settings in areas where COVID-19 transmission is high or substantial.* Findings from this investigation suggest that even jurisdictions without substantial or high COVID-19 transmission might consider expanding prevention strategies, including masking in indoor public settings regardless of vaccination status, given the potential risk of infection during attendance at large public gatherings that include travelers from many areas with differing levels of transmission.

Causes of death among Federal Black Lung Benefits Program beneficiaries enrolled in Medicare, 1999-2016.

BACKGROUND: Coal miners with totally disabling pneumoconiosis are eligible for benefits through the Federal Black Lung Benefits Program (FBLP). We identify the causes of death among Medicare beneficiaries with a claim for which the FBLP was the primary payer and compare these causes of death to all deceased Medicare beneficiaries to better understand elevated death and disease among miners with occupational respiratory exposures. METHODS: From 1999 to 2016 Medicare data, we extracted beneficiary and National Death Index data for 28,003 beneficiaries with an FBLP primary payer claim. We summarized the International Classification of Diseases, Clinical Modification 10th revision-coded underlying causes of death and entity-axis multiple causes of death for 22,242 deceased Medicare beneficiaries with an FBLP primary payer Medicare claim and compared their causes of death to the deceased Medicare beneficiary population. RESULTS: Among deceased FBLP beneficiaries, the three leading underlying causes of death were chronic obstructive pulmonary disease, unspecified (J44.9, 10.1%), atherosclerotic heart disease (I25.1, 9.3%), and coal workers' pneumoconiosis (CWP) (J60, 9.2%). All diseases of the respiratory system combined (J00-J99) were the underlying cause of death for 29.1% of all beneficiaries, with pneumoconioses (J60-J64) as the underlying cause for 11.0% of all beneficiaries. CONCLUSIONS: Coal miners enrolled in Medicare with an FBLP primary payer claim were more likely to have specific respiratory and cardiovascular diseases listed as a cause of death than deceased Medicare beneficiaries overall, and were also more likely to die from CWP or any pneumoconioses.

Assessment of pneumoconiosis in surface coal miners after implementation of a national radiographic surveillance program, United States, 2014-2019.

BACKGROUND: Pneumoconiosis can occur in surface coal miners. The Coal Workers' Health Surveillance Program (CWHSP) has only included surface coal miners as part of its regular disease surveillance since 2014. This analysis identifies the prevalence of pneumoconiosis among working surface coal miners participating in the CWHSP since their initial inclusion, through 2019. METHODS: Working surface coal miners who had chest radiographs through the CWHSP from January 1, 2014 through December 31, 2019 were included in this analysis. Demographic information, mining tenure and occupation, and radiographic classifications according to the International Labour Office system were included from each miner's most recent encounter with the CWHSP. Prevalence ratios were calculated comparing the prevalence of the disease by region and occupation by log-binomial regression. RESULTS: Pneumoconiosis was present in 109 (1.6%) surface coal miners, including 12 miners with progressive massive fibrosis, the most severe form of the disease. After taking surface mining tenure into account, surface miners in Central Appalachia (prevalence ratio [PR], 3.2; 95% confidence interval [CI], 2.2-4.7) and surface miners who worked as a driller or blaster (PR, 2.1; 95% CI, 1.3-3.5) were at increased risk of pneumoconiosis. CONCLUSION: The occurrence of pneumoconiosis in surface coal miners supports including them within a systematic respiratory health surveillance program. The current surveillance findings are consistent with past findings of pneumoconiosis, particularly silicosis, in surface mining occupations such as drilling and blasting.

Transplantation for work-related lung disease in the USA.

OBJECTIVES: Work-related lung diseases (WRLDs) are entirely preventable. To assess the impact of WRLDs on the US transplant system, we identified adult lung transplant recipients with a WRLD diagnosis specified at the time of transplant to describe demographic, payer and clinical characteristics of these patients and to assess post-transplant survival. METHODS: Using US registry data from 1991 to 2018, we identified lung transplant recipients with WRLDs including coal workers' pneumoconiosis, silicosis, asbestosis, metal pneumoconiosis and berylliosis. RESULTS: The frequency of WRLD-associated transplants has increased over time. Among 230 lung transplants for WRLD, a majority were performed since 2009; 79 were for coal workers' pneumoconiosis and 78 were for silicosis. Patients with coal workers' pneumoconiosis were predominantly from West Virginia (n=31), Kentucky (n=23) or Virginia (n=10). States with the highest number of patients with silicosis transplant were Pennsylvania (n=12) and West Virginia (n=8). Patients with metal pneumoconiosis and asbestosis had the lowest and highest mean age at transplant (48.8 and 62.1 years). Median post-transplant survival was 8.2 years for patients with asbestosis, 6.6 years for coal workers' pneumoconiosis and 7.8 years for silicosis. Risk of death among patients with silicosis, coal workers' pneumoconiosis and asbestosis did not differ when compared with patients with idiopathic pulmonary fibrosis. CONCLUSIONS: Lung transplants for WRLDs are increasingly common, indicating a need for primary prevention and surveillance in high-risk occupations. Collection of patient occupational history by the registry could enhance case identification and inform prevention strategies.

Pneumoconiosis progression patterns in US coal miner participants of a job transfer programme designed to prevent progression of disease.

OBJECTIVES: Pneumoconiosis prevalence and severity among US coal miners has been increasing for the past 20 years. An examination of the current approaches to primary and secondary prevention efforts is warranted. One method of secondary prevention is the Mine Safety and Health Administration-administered part 90 option programme where US coal miners with radiographic evidence of pneumoconiosis can exercise their right to be placed in a less dusty area of the mine. This study focuses on characterising the progression of disease among US coal miners who participated in the National Institute for Occupational Safety and Health-administered Coal Workers' Health Surveillance Programme (CWHSP) and exercised their part 90 job transfer option. METHODS: Chest radiograph classifications of working underground coal miners who exercised their part 90 job transfer option during 1 January 1986 to 21 November 2016 and participated in the CWHSP during 1 January 1981 to 19 March 2019 were analysed. RESULTS: 513 miners exercised their part 90 option and participated in the CWHSP at least once during this time period. Of the 149 miners with ≥2 radiographs available, 48 (32%) showed progression after exercising part 90 and had more severe disease prior to exercising, compared with miners who did not progress (severity score of 2.8 vs 1.7, p=0.0002). CONCLUSION: The part 90 job transfer option programme is not routinely used as intended to prevent progression of pneumoconiosis among US coal miners. The one-third of miners who participated in part 90 and continued to progress, exercised their part 90 option at a later stage of disease compared with non-progressors.

Patterns of progressive massive fibrosis on modern coal miner chest radiographs.

Clinical teaching generally asserts that large opacities of progressive massive fibrosis (PMF) on chest radiographs present primarily bilaterally in the upper lung zones, and with an elevated background profusion of small opacities. However, the contemporary basis for these descriptions is limited.Radiographs taken for the Coal Workers' Health Surveillance Program during 2000-2015 and previously determined to have large opacities ("PMF radiographs", n = 204), and a random sample previously deemed free of large opacities (n =22), were independently reevaluated by three National Institute for Occupational Safety and Health (NIOSH) B Readers. Large opacities were noted primarily in the upper right (41%) or upper left (28%) lung zone, but 31% were in middle or lower zones. Unilateral involvement was observed in 34% of readings, with right lung predominance (82%). The median small opacity profusion category for the radiographs with PMF was 2/1. The number of large opacities was not correlated with small opacity profusion category. The "classic" descriptions of PMF as bilateral, associated with elevated background profusions of small pneumoconiotic opacities, were each absent in a third of miners.

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.

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.

Current Review of Pneumoconiosis Among US Coal Miners.

PURPOSE OF REVIEW: This review summarizes recent research on pneumoconiosis in coal workers following the identification of the resurgence of this disease among US coal miners in the early 2000s. We describe the impact of this research and how this has led to increased public attention, benefitting affected miners. RECENT FINDINGS: The latest research shows that the prevalence of pneumoconiosis, including progressive massive fibrosis, continues to increase, especially in central Appalachia. Contributing factors may include mining of thin coal seams or cutting rock to access coal, which may expose miners to coal mine dust with a higher content of silica and silicates than in the past. The impact of recently implemented changes, such as the reduced occupational exposure limit for respirable coal mine dust and the introduction of continuous personal dust monitors, will likely take years to appropriately evaluate.

Continued increase in prevalence of r-type opacities among underground coal miners in the USA.

INTRODUCTION: Respirable crystalline silica exposure has been implicated in the resurgence of coal workers' pneumoconiosis (CWP) in the USA. A 2010 report found an increasing prevalence of r-type opacities, which are associated with silicosis lung pathology, on the radiographs of working underground coal miners in central Appalachia. This analysis updates that report by assessing the prevalence of r-type opacities during 2010-2018 compared with earlier decades. METHODS: Data from the Coal Workers' Health Surveillance Program were used to calculate the prevalence of r-type opacities on radiographs of working underground coal miners. The data were restricted to radiographs taken during 1 January 1980 to 15 September 2018. The presence of r-type opacities was defined as an r-type classification for either the primary or secondary shape/size of small opacities. Prevalence ratios for r-type opacities were calculated using log binomial regression. RESULTS: Radiograph classifications for 106 506 miners were included in analysis. For the USA overall, the prevalence of r-type opacities among miners with radiographs taken during 2010-2018 compared with 1980-1989 has increased (PR 2.4; 95% CI 1.9 to 3.0). For central Appalachia, the proportion of r-type opacities observed increased when comparing 1980-1989 to 2010-2018 (PR 6.0; 95% CI 4.6 to 7.9). CONCLUSIONS: The prevalence of r-type opacities on the radiographs of Appalachian underground coal miners continues to increase, implicating exposure to crystalline silica in respirable coal mine dust. The current findings underscore the importance of monitoring and controlling exposure to silica in coal mines.

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.