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.

OBJECTIVE:The objective of this study was to characterize workplace toluene diisocyanate (TDI) exposures using standardized industrial hygiene exposure assessment procedures for use in a prospective epidemiologic study of occupational asthma.METHODS:Over 2300 representative routine full shift time-weighted average (TWA) and short-term high potential exposure tasks (HPETs) air samples in groups across three TDI plants were collected over a nearly 7-year period.RESULTS:Data-derived similar exposure groups (SuperSEGs) were developed across the plants based on TWA sampling using cluster analysis. Individual cumulative exposure estimates were developed on the basis of the SuperSEGs.CONCLUSION:Workplace TWA exposures to TDI were adequately characterized quantitatively, but HPET exposures were adequately characterized only by qualitative measures. The mean TWA exposure was 0.65 parts per billion for 1594 routine samples. These TWA and HPET exposures can be used to support exposure-response analyses.

Objective: The objective of this study was to characterize workplace toluene diisocyanate (TDI) exposures using standardized industrial hygiene exposure assessment procedures for use in a prospective epidemiologic study of occupational asthma. Methods: Over 2300 representative routine full shift time-weighted average (TWA) and short-term high potential exposure tasks (HPETs) air samples in groups across three TDI plants were collected over a nearly 7-year period. Results: Data-derived similar exposure groups (SuperSEGs) were developed across the plants based on TWA sampling using cluster analysis. Individual cumulative exposure estimates were developed on the basis of the SuperSEGs. Conclusion: Workplace TWA exposures to TDI were adequately characterized quantitatively, but HPET exposures were adequately characterized only by qualitative measures. The mean TWA exposure was 0.65 parts per billion for 1594 routine samples. These TWA and HPET exposures can be used to support exposure–response analyses.

Controlling beryllium inhalation exposures to comply with regulatory levels (2 micro g m(-3) of air) does not appear to prevent beryllium sensitization and chronic beryllium disease (CBD). Additionally, it has proven difficult to establish a clear inhalation exposure-response relationship for beryllium sensitization and CBD. Thus, skin may be an important route of exposure that leads to beryllium sensitization. A 2000 survey had identified prevalence of sensitization (7%) and CBD (4%) in a beryllium alloy facility. An improved particulate migration control program, including dermal protection in production areas, was completed in 2002 at the facility. The purpose of this study was to evaluate levels of beryllium in workplace air, on work surfaces, on cotton gloves worn by employees over nitrile gloves, and on necks and faces of employees subsequent to implementation of the program. Over a 6 day period, we collected general area air samples (n = 10), wipes from routinely handled work surfaces (n = 252), thin cotton glove samples (n = 113) worn by employees, and neck wipes (n = 109) and face wipes (n = 109) from the same employees. In production, production support and office areas geometric mean (GM) levels of beryllium were 0.95, 0.59 and 0.05 micro g per 100 cm(2) on work surfaces; 42.8, 73.8 and 0.07 micro g per sample on cotton gloves; 0.07, 0.09 and 0.003 micro g on necks; and 0.07, 0.12 and 0.003 micro g on faces, respectively. Correlations were strong between beryllium in air and on work surfaces (r = 0.79), and between beryllium on cotton gloves and on work surfaces (0.86), necks (0.87) and faces (0.86). This study demonstrates that, even with the implementation of control measures to reduce skin contact with beryllium as part of a comprehensive workplace protection program, measurable levels of beryllium continue to reach the skin of workers in production and production support areas. Based on our current understanding of the multiple exposure pathways that may lead to sensitization, we support prudent control practices such as use of protective gloves to minimize skin exposure to beryllium salts and fine particles.

BACKGROUND Following employee respiratory concerns, we investigated the health effects of rayon flock exposure at a card manufacturing plant. METHODS We conducted a cross-sectional survey including environmental evaluation, standardized questionnaires, spirometry, carbon monoxide diffusing capacity testing, and methacholine challenge testing. RESULTS From a total of 239 participants, 146 (61%) reported working at least 1 hr per week in areas where flock-coated cards are processed (flock workers) and 47 (20%) reported cleaning equipment with compressed air. These workers had generally higher prevalences of respiratory symptoms. Flock workers and employees with longer tenure at areas where flock-coated cards are processed were more likely to have restrictive impairment of lung function. Although dust and fiber samples were largely below the detection limits, peak exposures to airborne particulate occurred during cleaning with compressed air. CONCLUSIONS Working with rayon flock and cleaning with compressed air were associated with health effects in workers at this plant.

W e read with great interest the Letter to the Editor by Newman and colleagues(1) in response to our article entitled “Industries in the United States with Airborne Beryllium Exposure and Estimates of the Number of Current Workers Potentially Exposed.”(2) We commend the authors of the letter for raising a number of issues that, while clearly beyond the scope of our article, are relevant to the health of beryllium workers. At this time, we want to clarify some issues regarding our goals and methods. In the hierarchy of prevention (i.e., primary, secondary, and tertiary), primary prevention is usually considered the most desirable since it is concerned with protecting susceptible individuals from disease onset. The goal of our article was to further the cause of primary prevention of beryllium sensitization and chronic beryllium disease (CBD). Specifically, we used measurements of airborne beryllium collected by the Occupational Safety and Health Administration (OSHA) to identify industries where beryllium is present and to estimate the number of employees in the United States who are currently potentially exposed to beryllium. Our article alerts workers and company officials to the potential for beryllium exposure and the associated risks for beryllium sensitization and CBD. The authors of the Letter to the Editor offered the criticism that the “paper underestimates the number of former workers who have been exposed to beryllium.” Primary prevention is pertinent to currently exposed workers. Starting with the title of our article and throughout it, we clearly stated that we would estimate the number of current workers rather than the number of former workers. Personnel at the Department of Energy (DOE) had provided us estimates of the number of former workers who had enrolled in medical surveillance, and we reported those estimates. Also, a month before the publication of our article, other researchers published an estimate of the number of construction workers who had ever been employed at DOE sites and had potentially been exposed to beryllium.(3) A comprehensive estimate of the number of workers from both the public and private sectors who had formerly been exposed to beryllium would complement our article, with its focus on primary prevention, by serving secondary and tertiary prevention. Newman and colleagues pointed out that the OSHA data we used were based on surveys conducted in a fraction of the companies in the United States. To address this limitation, our algorithm for estimating the number of exposed workers extended beyond just the companies where beryllium was measured to include an estimate of exposed workers in similar companies where samples were not taken. Newman and colleagues also expressed concern that OSHA did not conduct air measurements for beryllium in companies where it was not suspected. In fact, the exposure data from OSHA did include measurements of beryllium in worksites where it was not suspected. This occurred because samples sent by OSHA inspectors for metal analyses were subjected to laboratory tests for a variety of metals, even if only a single metal was the focus of attention. We used the OSHA samples to identify many users, “downstream” of the primary beryllium producer, who were very likely unaware of the potential for exposure. We do not know of another industrial hygiene data base in the United States that has measurements of beryllium in worksites where it was not suspected. We and other researchers have identified beryllium sensitization and disease associated with airborne levels below 0.1 μg/m3 beryllium.(4,5) The authors of the Letter to the Editor criticized the absence of exposure measurements below 0.1 μg/m3. However, given the field and laboratory methods used by OSHA during the relevant period of sample collection (i.e., 1979–1996), 0.1 μg/m3 was probably the minimal concentration that could be measured reliably from a personal 8-hour sample. Moreover, 0.1 μg/m3 might have been recorded in the OSHA database in some instances as a default level when the laboratory reported that no beryllium was detected. Consistent with our awareness of the risk associated with low exposures, we recommended that OSHA and others should have the capability to measure air concentrations below 0.1 μg/m3 when monitoring beryllium currently and in the future. We would like to offer a final recommendation to further the prevention of beryllium sensitization and CBD. OSHA is collecting data on beryllium exposures and associated health risks in preparation for proposing a new standard. In the past, OSHA standards have impacted workers both in the United States and in other countries that look to OSHA for guidance. We have provided OSHA access to beryllium data at NIOSH and understand that OSHA has requested relevant data from others. We urge all researchers and users of beryllium to cooperate with OSHA in order to ensure the development of a standard that will adequately protect current and future workers exposed to beryllium.