National Institute Of Occupational Safety And Health Research Articles

Exposures and Health Effects of Diacetyl and 2,3-Pentanedione in a Coffee Processing Facility

Diacetyl and 2,3-pentanedione are alpha-diketones that are generated during the coffee roasting process and have been shown to be related to respiratory symptoms, abnormal lung function, and in rare cases, an irreversible disease called obliterative bronchiolitis. This study measured personal exposures in a coffee roastery in New Zealand using thermal desorption tubes and explored the prevalence of respiratory symptoms with a health questionnaire. Exposures from task samples were highest for grinding (Geometric Mean (GM): 22.5 ppb diacetyl; GM: 19.3 ppb 2,3-pentanedione), followed by packaging (GM: 10.8 ppb diacetyl; GM: 9.3 ppb 2,3-pentanedione) and then roasting (GM: 4.7 ppb diacetyl; GM: 4.1 ppb diacetyl). 8-h time-weighted average (TWA) diacetyl exposures exceeded the National Institute of Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL) of 5 ppb for Roaster/Packager (GM: 6.6 ppb) and Grinder (GM: 5.3 ppb). 8-h TWA concentrations were below the NIOSH REL of 9.3 ppb for 2,3-pentanedione (Roaster/Packager, GM: 5.7 ppb; Grinder, GM: 4.6 ppb). Workers reported nose, eye symptoms and systemic symptoms (flu-like illness or achy joints, fever or chills, or unusual tiredness or fatigue). The results indicated that exposure was highest for tasks involving ground coffee beans and that coffee processing workers can be exposed to alpha-diketones above the NIOSH RELs. Further research into alpha-diketone exposure and health effects, and control measures to minimise exposure are recommended.

Effects of dust controls on respirable coal mine dust composition and particle sizes: case studies on auxiliary scrubbers and canopy air curtain

Control of dust in underground coal mines is critical for mitigating both safety and health hazards. For decades, the National Institute of Occupational Safety and Health (NIOSH) has led research to evaluate the effectiveness of various dust control technologies in coal mines. Recent studies have included the evaluation of auxiliary scrubbers to reduce respirable dust downstream of active mining and the use of canopy air curtains (CACs) to reduce respirable dust in key operator positions. While detailed dust characterization was not a focus of such studies, this is a growing area of interest. Using preserved filter samples from three previous NIOSH studies, the current work aims to explore the effect of two different scrubbers (one wet and one dry) and a roof bolter CAC on respirable dust composition and particle size distribution. For this, the preserved filter samples were analyzed by thermogravimetric analysis and/or scanning electron microscopy with energy dispersive X-ray. Results indicate that dust composition was not appreciably affected by either scrubber or the CAC. However, the wet scrubber and CAC appeared to decrease the overall particle size distribution. Such an effect of the dry scrubber was not consistently observed, but this is probably related to the particular sampling location downstream of the scrubber which allowed for significant mixing of the scrubber exhaust and other return air. Aside from the insights gained with respect to the three specific dust control case studies revisited here, this work demonstrates the value of preserved dust samples for follow-up investigation more broadly.

Bibliometric Analysis of Publications on “Hazards and Health Effects Associated with Welding” From 2010 – 2023

An overview of the hazards and health effects associated with exposure to welding fumes is provided in this paper through adaptations from various sources. The growing concerns around welding and its attendant health effects are valid as welding fumes are inherently hazardous and are composed of particulate matter from condensed metals and obnoxious gases such as Ozone which have been implicated in the aetiology and pathophysiology of many diseases including cancer. Information currently available from various published study works is described in the review. In accordance with the bibliometric analysis, "The United States" ranks as the most prolific contributor, with a large collection of works from active organizations such as the National Institute of Occupational Safety and Health (NIOSH). Additionally, author cooperation has increased recently and is more common in groups. Three hot themes in welding-related hazards and health effects—"human," "age," and "occupational exposure"—were identified across all keyword analyses. Furthermore, oxidative stress, occupational diseases, risk management, cohort studies, and air pollutants in welding were identified as new themes by the keywords analysis. To the extent that we are aware, this study is the first explicit bibliometric approach to visualize the research field of health and hazard impacts related to welding. It is helpful for locating hotspots in active research now and for speculating on prospective future research areas.

Contribution Analysis of a Complex System During Disruptions

The U.S. National Institute of Occupational Safety and Health (NIOSH) supports 11 regional centers to conduct research and outreach in agriculture, fishing, and forestry. The Southwest Center for Agricultural Health, Injury Prevention, and Education serves Arkansas, Louisiana, New Mexico, Oklahoma, and Texas. The 2016–2022 evaluation used contribution analysis since it is effective in evaluating complex systems with diverse stakeholders and multiple projects, with partners working toward the same outcome over time. The evaluation responded to the disruptions in program implementation caused by the COVID-19 pandemic and to NIOSH modifications to key elements of contribution analysis procedures.

Improving the Safety Culture and Climate of Smaller Construction Firms: A Necessary Addition to the OSH Intervention Model

The unsatisfactory safety performance of smaller construction firms has been identified as a challenge that requires further investigation and intervention. There are few studies, if any, that investigate the safety culture and climate of smaller construction firms. This study represents a much needed attempt to clarify the obstacles that prevent smaller construction firms from creating a satisfactory level of safety culture and climate. The study aims to propose a framework that is better suited for smaller construction firms based on literature. To validate the proposed framework, a questionnaire was designed and administered. The findings support the proposed framework and deliver an objective defining criterion that classifies smaller construction firms into small firms and micro firms. Among other factors, the findings suggest that smaller construction firms often lack systematic safety operations due to the absence of safety personnel. Accordingly, a revised occupational safety and health (OSH) model for smaller construction firms has been developed based on the model previously developed by the National Institute of Occupational Safety and Health (NIOSH). It is expected that this study will improve safety intervention programs for smaller construction firms and the safety performance of the construction industry.

Occupational health risk assessment of airborne formaldehyde in medical laboratories.

The professional use of formaldehyde is a major occupational health concern in medical laboratory operations. Quantification of various risks associated with chronic exposure to formaldehyde may help in understanding the related hazards. This study designed to assess the health risks associated with inhalation exposure to formaldehyde involving biological, cancer, and non-cancer risks in medical laboratories. This study was performed in the hospital laboratories at Semnan Medical Sciences University. Risk assessment was performed in pathology, bacteriology, hematology, biochemistry, and serology laboratories with 30 employees, using formaldehyde in their daily routine operations. We determined area and personal exposures to airborne contaminant, applied standard air sampling, and analytical method recommended by National Institute of Occupational Safety and Health (NIOSH). We addressed formaldehyde-specific hazard by estimating peak blood level, life cancer risk, and the hazard quotient of non-cancer risks, adapted from Environmental Protection Agency (EPA) assessment method. The airborne formaldehyde concentrations in the laboratory personal samples ranged 0.0156-0.5940ppm (mean = 0.195ppm, SD = 0.048) and area exposure ranged 0.0285-1.0810ppm (mean = 0.462ppm, SD = 0.087). Based on workplace exposure, peak blood levels of formaldehyde were estimated at minimum 0.0026mg/l to maximum 0.152mg/l (mean = 0.015mg/l, SD = 0.016). The mean cancer risk levels in terms of area and personal exposures were estimated respectively at 3.93 E - 8μg/m3 and 1.84 E - 4μg/m3, and for the non-cancer risk levels of the same exposures measured respectively at 0.03μg/m3 and 0.07μg/m3. Formaldehyde levels were significantly higher among laboratory employees, especially bacteriology workers. Exposure and risk could be minimized by strengthening control measures including the use of management controls, engineering controls, and respiratory protection equipment to reduce exposure levels of all workers to less than the allowed exposure limits and improve indoor air quality in the workplace.

Relationship Between Musculoskeletal Load and Weight of Manual Fish Handling Via 2D Simulation

Fisherman experienced work-related musculoskeletal disorders (WMSDs) due to manual handling. Especially, manual handling for heavy fish makes physical load for fisherman. To prevent these WMSDs, fisherman should know the limit of weight in manual fish handling. Thus, the objective of this study was to find the relationship between the musculoskeletal load and weight of manual fish handling. This investigation was performed by the 2D musculoskeletal simulation. Posture of fishermen during manual fish handling on the commercial fishing boat was obtained from the Fishnet Open Images Database. Compression force of L5-S1 and joint torque of elbow, shoulder, knee, and ankle as musculoskeletal load were calculated by BlessPro2 software. The weight values of bigeye tuna, yellowfin tuna, and albacore tuna were used for this simulation. The results showed that compression force of L5-S1 and joint torque were increased with fish weight. In addition, the compression forces of L5-S1 during manual handling for bigeye tuna and yellowfin tuna were much larger than 3400 N as injury threshold of the National Institute of Occupational Safety and Health (NIOSH). These results indicate that fishermen should avoid heavy fish such as bigeye tuna and yellowfin tuna in manual fish handling for preventing WMSDs.

A Logistic Regression Model for Biomechanical Risk Classification in Lifting Tasks.

Lifting is one of the most potentially harmful activities for work-related musculoskeletal disorders (WMSDs), due to exposure to biomechanical risk. Risk assessment for work activities that involve lifting loads can be performed through the NIOSH (National Institute of Occupational Safety and Health) method, and specifically the Revised NIOSH Lifting Equation (RNLE). Aim of this work is to explore the feasibility of a logistic regression model fed with time and frequency domains features extracted from signals acquired through one inertial measurement unit (IMU) to classify risk classes associated with lifting activities according to the RNLE. Furthermore, an attempt was made to evaluate which are the most discriminating features relating to the risk classes, and to understand which inertial signals and which axis were the most representative. In a simplified scenario, where only two RNLE variables were altered during lifting tasks performed by 14 healthy adults, inertial signals (linear acceleration and angular velocity) acquired using one IMU placed on the subject's sternum during repeated rhythmic lifting tasks were automatically segmented to extract several features in the time and frequency domains. The logistic regression model fed with significant features showed good results to discriminate "risk" and "no risk" NIOSH classes with an accuracy, sensitivity and specificity equal to 82.8%, 84.8% and 80.9%, respectively. This preliminary work indicated that a logistic regression model-fed with specific inertial features extracted by signals acquired using a single IMU sensor placed on the sternum-is able to discriminate risk classes according to the RNLE in a simplified context, and therefore could be a valid tool to assess the biomechanical risk in an automatic way also in more complex conditions (e.g., real working scenarios).

Analisis Beban Kerja menggunakan Metode Recommended Weight Limit dan Lifting Index

The purpose of this study is to determine the factors that affect movement, correct body posture in doing work so that injuries do not occur at work and the maximum load that can be lifted by workers. The case study was conducted in a rubber processing industry The calculation of the Recommended Weight Limit (RWL) for each worker in the lifting of rubber raw materials and lifting to weighing has a weight range of 30-50 kg in each lift. Documentation results obtained from horizontal distance (H), vertical distance (V), asymmetric angle (A), load starting point (D), number of loads lifted per minute (F), moment of force (C). In the results of the RWL calculation, the recommended weight of the load is between 11.06 kg and 21.24 kg. The recommended weight of the load for workers in the lifting of rubber raw materials and lifting to weighing is based on the calculation of the Recommended Weight Limit (RWL), the level of risk based on the provisions of the National Institute of Occupational Safety and Health (NIOSH) Lifting Index is that the effect of back injury is still identified when viewed from the calculation results of the Lifting Index (LI) value. The LI value for workers is more than 1 (one) so it needs immediate repair. Workload solutions that can be applied to the lifting of rubber raw materials and lifting to weighing are reducing the weight of the load and improving work methods.

Carcinogenic and health risk assessment of respiratory exposure to acrylonitrile, 1,3-butadiene and styrene in the petrochemical industry using the US Environmental Protection Agency method

Objectives. This study aimed to assess carcinogenic and health risks of respiratory exposure to acrylonitrile, 1,3-butadiene and styrene (ABS) in the petrochemical industry. Methods. This cross-sectional study was conducted in a petrochemical plant producing ABS copolymers. Respiratory exposure to each of acrylonitrile, 1,3-butadiene and styrene was measured using methods No. 1604, No. 1024 and No. 1501 of the National Institute of Occupational Safety and Health (NIOSH), respectively. The US Environmental Protection Agency (USEPA) method was used to assess carcinogenic and health risks. Results. The average occupational exposure to ABS was 560.82 µg m–3 for 1,3-butadiene, 122.8 µg m–3 for acrylonitrile and 1.92 µg m–3 for styrene. The average lifetime cancer risk in the present study was 2.71 × 10−3 for 1,3-butadiene, 2.1 × 10−3 for acrylonitrile and 6.6 × 10−3 for styrene. Also, the mean non-cancer risk (hazard quotient) among all participants for each of 1,3-butadiene, acrylonitrile and styrene was 4.04 ± 6.93, 10.82 ± 14.76 and 0.19 ± 0.11, respectively. Conclusion. The values of carcinogenic and health risks in the majority of the subjects were within the unacceptable risk levels due to exposure to ABS vapors. Hence, corrective actions are required to protect the workers from non-cancer and cancer risks.

PENGEMBANGAN METODE ANALISIS BENZENA, TOLUENA, DAN XYLENA DALAM UDARA LINGKUNGAN KERJA MENGGUNAKAN IN HOUSE METODE DI PT UNILAB PERDANA

Benzene, Toluene and Xylene (BTX) compounds are compounds that have colorless and flammable characteristics, have a sweet odor with a low toxicity level, and are not soluble in water. This compound is often used as a solvent, extractor and as a chemical intermediary. The testing of BTX parameters in the working environment refers to the National Institute of Occupational Safety and Health (NIOSH) method number 1501. The method must be modified or developed in terms of equipment and instruments, due to looking at the condition of the materials and equipment in PT UP, i.e. using different columns, capillary columns, fused silica, 30m x 0.32-mm ID; 1-μm film 100% PEG becomes a Rtx-5MS column, and measurements using a FID detector become a Mass Spectrometer detector. And the solvent used is Carbon Disulfiida (CS2) to Methanol for gas chromatography. CS2 solvents are carcinogenic in the body so that they are harmful to human health. Besides being harmful to health, the waste produced by CS2 causes damage to the ozone layer on the earth's surface so that it can trigger global warming which will make the earth feel hot. In addition, CS2 solvents in Indonesia have begun to be reduced in production and will be illegal inthe future. Therefore, this method needs to be validated before doing a routine analysis so that the data obtained is valid.

VALIDASI METODE UJI SENYAWA CYCLOHEXANE DI UDARA LINGKUNGAN KERJA DENGAN BERBAGAI MODIFIKASI METODE SECARA GAS CHROMATOGRAPHY MASS SPECTROMETRY

Determination of the cyclohexane compound used refers to the National Institute of Occupational Safety and Health (NIOSH) method number 1500. Validation of the determination of cyclohexane in air samples of the work environment needs to be done due to modifications between them in different columns, glass columns 3.0 mx 2-mm , 20% SP-2100 on 80/100 mesh Supelcoport becomes Rtx-5MS column, the injector temperature difference, column temperature, detector temperature, and the test material used is cyclohexane pa to cyclohexane for gas chromatography, differences in measurements using FID detectors to spectrometer detectors mass. This experiment aims to ensure the performance of the cyclohexane determination method in the air sample of PT UP's work environment by gas chromatography mass spectrometry (GCMS) in accordance with the accepted method requirements set by PT. Unilab Prime. If all parameters meet the acceptance requirements, then this method can be used for routine analysis. Validation parameters carried out include linearity test, instrument detection limit (LDI), quantitation limit (LK), precision,accuracy, and strength of the method (robustness) using gas spectrometer mass chromatography. Based on the experimental results obtained by the value of the correlation coefficient linearity test (r) of 0.9998,% SBR for the precision test of 1.64%,% recovery obtained range of 89.26% - 105.35%. The instrument detection limit value is 0,0003mg / mL, the quantization limit is 0.0010mg / mL. Testing the strength parameters of the method (Robustness) produces cyclohexane concentrations in accordance with the accepted requirements of the working range of cyclohexane 0.5000mg / mL. Based on the test results obtained the performance of the cyclohexane determination method that has undergone modification in a sample of working air environment by gas chromatography mass spectrometry (GCMS) in accordance with the requirements set by thecompany so that it can be used for routine analysis in the PT Unilab Perdana environmental laboratory.

A PRELIMINARY SURVEY ON SAFETY PRACTICES AT CONSTRUCTION SITE: TOWARDS SAFE ENVIRONMENT FOR PUBLIC

The construction industry is globally known as one of the most hazardous workplaces. Companies in the construction sector are undeniably often focused on completing projects on time, which results in tight work schedules and increases the risks of regular construction site activities, especially for the public who lives in the area. Inadequate rules and regulations in public safety and construction sites not practicing the safety practices to protect the public from harm are potential to cause public accidents to happen. Additionally, little improvement in safety practices at the construction sites and lack of awareness in implementing proper safety practices at a construction site could cause the increasing the rate of public accidents too. This study merely aims to explore the safety practices to be implemented at a construction site in a way to prevent public accidents from occurring. In order to achieve the aim, this study has two (2) objectives; 1: to determine the experience in handling accident cases involving the public at a construction site, and, objective 2: to explore the safety practices to be implemented at the construction site. For this preliminary survey, the qualitative research design was selected and the total number of five (5) professional individuals specialized in safety and health in construction sites were chosen as interviewees based on their experiences in handling public safety issues in construction sites. The results show the most recommended safety practices that need to be implemented which is barricade all entrances and exits of the construction site to prevent access from the public. This study provides good insights to the Department of Occupational Safety and Health (DOSH), National Institute of Occupational Safety and Health (NIOSH), and Construction Industry Development Board (CIDB) in identifying the need for safety practices to prevent public accidents at the construction site in congested urban areas.

Ergonomic Hazards Associated with Brick Making in a Tropical Wetland: The Case of Sironga Wetland, Kenya

Brick production processes involve a lot of manual handling which may lead to several ergonomic hazards. This is due to the nature of the work forcing them to bend or carry loads including frequency, time and weight of the load carried at a time. This study was done with the aim of identifying the ergonomic hazards in the brick making industry and the results compared with the local and international standards on load carrying. Different roles were played in brick production by both men and women. Females were mostly involved in carrying bricks on the head while males were involved in mixing and moulding of clay. However, both male and female workers required exerting force. Results revealed that workers were carrying loads more than 25kg against NOISH (National Institute of Occupational Safety and Health) and (International Labour Organization) ILO which stipulates the maximum weight to be lifted, carried on head or shoulders, pulled or pushed is 25 kg for men and 20 kg for women. Heavy load carrying exposes them to several ergonomic hazards such as musculoskeletal discomfort (MSD) and disability. The study recommends ergonomic intervention

Control measures for airborne ammonia and respirable dust exposure in swine barns

ABSTRACT Extended exposure to airborne contaminants such as ammonia (NH3) and respirable dust in swine facilities has been associated with various health problems among swine barn workers. The overall goal of this study was to assess the impact of selected control measures, namely, canola oil sprinkling, low crude protein diet, high level of cleaning, and manure pH manipulation, on NH3 and respirable dust concentrations in swine production rooms through area sampling and on worker exposure to these contaminants in accordance with National Institute of Occupational Safety and Health (NIOSH) methods for occupational exposure monitoring. Results from five trials showed that low crude protein diet can be used for reducing worker exposure to NH3 while oil sprinkling can be used for controlling respirable dust levels in swine rooms. Reduction in airborne levels did not translate to reduction in occupational exposure. Commercial NH3 monitors showed higher readings than the standard NIOSH 6015 method.

Characterization of Naturally Occurring Alpha-Diketone Emissions and Exposures at a Coffee Roasting Facility and Associated Retail Café.

Alpha-diketones such as diacetyl and 2,3-pentanedione have been used as artificial flavorings in a variety of industries and are produced naturally when food products such as coffee beans are roasted. Exposure to these compounds has been associated with bronchiolitis obliterans, a rare and severe respiratory disease. In the current paper, we (i) evaluate which steps in the coffee production process are associated with the highest alpha-diketone emissions at a small craft coffee roaster and associated café, (ii) determine the extent to which direct-reading measurements of CO, CO2, and total volatile organic compounds (VOCs) can serve as lower-cost surrogate indicators for diacetyl concentrations, and (iii) conduct a limited emissions study to quantify the effect that the process variable of roast type has on diacetyl emissions from grinding beans. Exposure and area concentration data for diacetyl and 2,3-pentanedione were collected over 4 days of sampling at a single coffee roaster and associated café. Additional measurements of café patrons' exposure to diacetyl were collected in seven other craft roastery/cafes in Seattle, WA. For the emissions experiments, integrated area air samples for diacetyl were collected using sorbent tubes over 30-min intervals for each roast type with the sorbent tubes positioned next to a grinder placed in an exposure chamber. Sorbent tubes were analyzed for alpha-diketones using gas chromatography-mass spectrometry. A photoionization detector (PID) was also used to measure continuous total VOC concentrations at the coffee roastery, and during each grinding experiment. Diacetyl concentrations in five of the seven personal samples from the craft roastery were above the United States National Institute of Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL) of 5 ppb as an 8-h time-weighted average (TWA)-and one of the seven personal samples exceeded the NIOSH REL for 2,3-pentanedione-9.3 ppb as an 8-h TWA. Median diacetyl and 2,3-pentanedione emissions were highest at the bagging machine followed by the grinder, roaster, barista, and background areas. The arithmetic mean diacetyl concentrations from the seven personal samples collected from café patrons was 3.96 ppb, suggesting that diacetyl exposure poses a negligible health risk to café patrons. Correlations between diacetyl and total VOCs, CO, and CO2 showed that diacetyl was well correlated with total VOCs, but poorly correlated with CO and CO2. Based on our limited emissions study, French roast was associated with the highest mass emission factor of diacetyl. Results from the exposure assessment study indicated that coffee production workers at this facility had elevated exposures to diacetyl and 2,3-pentanedione compared to recommended guidelines, whereas baristas and café patrons received lower exposures. Area sampling showed that the areas with the highest alpha-diketone emissions were the grinder and the bagging machine, which are both areas associated with tasks involving ground roasted coffee. Future research could focus on designing and evaluating effective engineering controls, in the form of local exhaust ventilation, with the goal of reducing alpha diketone exposures, as well as conducting similar studies at other small-scale craft coffee roasters and cafés to better understand the variability in these emissions and exposures within these types of facilities.

Liver function alterations among workers in the shoe industry due to combined low-level exposure to organic solvents

This study aimed to investigate the potential hepatotoxicity, nephrotoxic, and hematotoxic effects of simultaneous occupational low-level exposure of shoe workers to a mixture of organic solvents. The study included 16 male and 55 female workers and non-exposed subjects (n = 60) in the control group. Along with a standard sets of hematological, liver enzymes (aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma-glutamyl transpeptidase (GGT), bilirubin total, bilirubin direct, blood glucose, urea, and creatinine were analyzed in all participants. Indoor air quality was monitored using a Gasmet Dx − 4000 multi-component analyzer. Despite the concentration levels of individual chemicals in shoe production units were below the permissible limits, the equivalent exposure (Em) values calculated based on the American Conference of Governmental Industrial Hygienists (ACGIH) and National Institute of Occupational Safety and Health (NIOSH) occupational exposure limits were higher than 1. Statistically significant increase of biochemical parameters (aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), total bilirubin, and direct bilirubin) was obtained in exposed workers of both genders compared with controls (p < 0.001). Calculated liver damage risk scores were significantly higher in both females and males compared with controls (p < 0.001). The multivariate logistic regression analysis showed that direct bilirubin was the most important predictor of organic solvent mixture exposure in the studied group of workers. These results suggest that combined exposure to organic solvents even at low concentrations may lead to hepatotoxicity.

Translating nanoparticle dosimetry from conventional in vitro systems to occupational inhalation exposures

As encouraged by Toxicity Testing in the 21st Century, researchers increasingly apply high-throughput in vitro approaches to identify and characterize nanoparticle hazards, including conventional aqueous cell culture systems to assess respiratory hazards. Translating nanoparticle dose from conventional toxicity testing systems to relevant human exposures remains a major challenge for assessing occupational risk of nanoparticle exposures. Here, we explored existing computational tools and data available to translate nanoparticle dose metrics from cellular test systems to inhalation exposures of silver nanoparticles in humans. We used the Multiple-Path Particle Dosimetry (MPPD) Model to predict nanoparticle deposition of humans exposed to 20 and 110 nm silver nanoparticles at 0.9 μg/m3 over an 8 h period, the proposed National Institute of Occupational Safety and Health (NIOSH) recommended exposure limit (REL). MPPD predicts 8.1 and 3.7 μg of silver deposited in an 8 h period for 20 and 110 nm nanoparticles, respectively, with 20 nm particles displaying nearly 11-fold higher total surface area deposited. Peak deposited nanoparticle concentrations occurred more proximal in the pulmonary tract compared to mass deposition patterns (generation 4 vs. generations 20–21, respectively) due to regional differences in lung lining fluid volumes. Assuming 0.4% nanoparticle dissolution by mass measured in previous studies predicted peak concentrations of silver ions in cells of 1.06 and 0.89 μg/mL for 20 and 110 nm particles, respectively. Both predicted concentrations are below the measured toxic threshold of 1.7 μg/mL of silver ions in cells from in vitro assessments. Assuming 4% dissolution by mass predicted 10-fold higher silver concentrations in tissues, peaking at 10.6 and 8.9 μg/mL, for 20 and 110 nm nanoparticles respectively, exceeding the observed in vitro toxic threshold and highlighting the importance and sensitivity of dissolution rates. Overall, this approach offers a framework for extrapolating nanotoxicity results from in vitro cell culture systems to human exposures. Aligning appropriate dose metrics from in vitro and in vivo hazard characterizations and human pulmonary doses from occupational exposures are critical components for successful nanoparticle risk assessment and worker protection providing guidance for designing future in vitro studies aimed at relevant human exposures.

1426. Increased Visits to Respiratory Protection Webpages during COVID-19

BackgroundCOVID-19 transmission is thought to occur mainly via respiratory droplets produced when an infected person coughs or sneezes. Respiratory protection devices, when properly fitted and used, can prevent this type of illness transmission.MethodsThe Centers for Disease Control and Prevention’s National Personal Protective Technology Laboratory (NPPTL) within the National Institute of Occupational Safety and Health (NIOSH) is responsible for the certification and approval of respirators for use in occupational settings. NPPTL maintains webpages with information on respiratory protection devices. We monitored the number of webpage views for several NPPTL webpages from January 1, 2020 to May 8, 2020. The number of webpage visits was then compared to significant events during the COVID-19 outbreak as well as the previous year’s webpage visits.ResultsThe landing page for NIOSH-approved N95 respirators received the most visits. This page received a total of 1,637,250 webpage visits with a peak of 63,715 on February 26, 2020, a 38,989% increase from the average daily page visits for that same month in 2019. This occurred on the same day as the White House gave its first televised briefing on COVID-19. The page providing general information on filtering facepiece respirators, including N95 respirators received 834,186 webpage visits with a peak of 20,520 on April 3, 2020, a 13,659% increase from the average daily webpage visits for that same month in 2019. This occurred on the same date as new CDC recommendations were provided for using cloth face masks in public places. The counterfeit respirator page maintained a steady, but small number of webpage visits, but increased from 4,261 on March 27, 2020 to 68,145 on March 29, 2020. This occurred as the first reports of fraudulent respirators were being published in the media. It then fell to 18,562 on March 30, 2020 and 13,093 on March 31, 2020. While most webpage visits were from the United States, visits from China, and Canada were higher than previous years.ConclusionDuring COVID-19 there was a large increase in the number of webpage visits for respiratory protection information which coincided with major events and media reports. Accurate, accessible respiratory protection information is an important resource during public health emergencies.Disclosures All Authors: No reported disclosures

A Bayesian Approach for Determining the Relationship Between Various Elongate Mineral Particles (EMPs) Definitions.

A variety of dimensions (lengths and widths) of elongate mineral particles (EMPs) have been proposed as being related to health effects. In this paper, we develop a mathematical approach for deriving numerical conversion factors (CFs) between these EMP exposure metrics and applied it to the Minnesota Taconite Health Worker study which contains 196 different job exposure groups (28 similar exposure groups times 7 taconite mines). This approach comprises four steps: for each group (i) obtain EMP dimension information using ISO-TEM 10312/13794 analysis; (ii) use bivariate lognormal distribution to characterize overall EMP size distribution; (iii) use a Bayesian approach to facilitate the formation of the bivariate lognormal distribution; (iv) derive conversion factors between any pair of EMP definitions. The final CFs allow the creation of job exposure matrices (JEMs) for alternative EMP metrics using existing EMP exposures already characterized according to the National Institute of Occupational Safety and Health (NIOSH)-defined EMP exposure metric (length >5 µm with an aspect ratio ≥3.0). The relationships between the NIOSH EMP and other EMP definitions provide the basis of classification of workers into JEMs based on alternate definitions of EMP for epidemiological studies of mesothelioma, lung cancer, and non-malignant respiratory disease.