Last data update: Jan 27, 2025. (Total: 48650 publications since 2009)
Records 1-30 (of 71 Records) |
Query Trace: Virji MA[original query] |
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Respiratory quaternary ammonium and volatile organic compound exposures experienced by home care aides during residential bathroom cleaning using conventional and green products
Quinn MM , Lindberg JE , Gore RJ , Sama SR , Galligan CJ , Kriebel D , Markkanen PK , LeBouf RF , Virji MA . Ann Work Expo Health 2024 INTRODUCTION: US home care (HC) aide visits to clients' homes typically involve cleaning and disinfecting (C&D) environmental surfaces, particularly in bathrooms. Some ingredients in C&D products are associated with respiratory illness: sodium hypochlorite (bleach), quaternary ammonium compounds (QACs), and volatile organic compounds (VOCs). This study assessed and compared aides' respiratory exposures to specific VOCs and QACs while using 2 conventional and 1 "green" household C&D spray products during bathroom cleaning. Measured exposures were compared to ingredients listed on publicly available sources. METHODS: Three C&D products were selected with principal active disinfecting ingredients: 1% to 5% sodium hypochlorite by weight ("bleach-based"); 0.1% to 1% QACs ("QACs-based"); and 0.05% thymol ("green"). Twenty-two aides were recruited to perform C&D tasks in a simulated residential bathroom constructed in an environmental monitoring laboratory. A balanced experimental study design involved each aide visiting the lab 4 times to perform typical cleaning tasks with the 3 products and distilled water (as a control), randomly assigned across the 4 visits. Aides wore air sampling equipment for breathing zone samples: canisters to collect whole air for VOC analyses and filter cassettes for QACs analyses. RESULTS: Aides performed 84 cleaning visits contributing approximately 20 air samples each for VOCs and QACs, for each of the 3 products and distilled water. In total, 38 unique VOCs were identified in the canister whole air samples: 20 in the QACs-based product samples, 15 in the bleach-based, and 10 in the green. Most VOCs were not listed in publicly available sources of cleaning product ingredients. Toxicity information was limited. Few VOCs had occupational exposure limits. The QACs-based product generated QACs aerosol: benzalkonium chloride (BAC)12 (geometric mean (GM) = 6.98 µg/m3), BAC14 (GM=2.97 µg/m3), BAC16 (GM=0.78 µg/m3); and the 3 QACs summed (GM=10.86 µg/m3). DISCUSSION: The use of C&D spray products for residential cleaning can generate respiratory exposures to complex mixtures of volatile and nonvolatile compounds. Notably, we measured aerosols containing QACs during the use of the QACs-based product. Dermal is usually considered the main route of exposure because QACs are nonvolatile salts. This study provides evidence that QACs inhalation exposure should be recognized and minimized in addition to the well-accepted dermal exposure routes. The green product generated the fewest VOCs. However, more toxicity information is needed on the health impacts of green C&D products. Spraying of C&D products, conventional and green, should be avoided. CONCLUSIONS: Aides' respiratory health should be protected from chemical exposures while performing C&D in home care. |
Eye and airway symptoms in hospital staff exposed to a product containing hydrogen peroxide, peracetic acid, and acetic acid
Blackley BH , Nett RJ , Cox-Ganser JM , Harvey RR , Virji MA . Am J Ind Med 2023 66 (8) 655-669 BACKGROUND: Sporicidal products containing hydrogen peroxide (HP), peracetic acid (PAA), and acetic acid (AA) are used widely in multiple industries, including healthcare. Despite widespread use in healthcare, few studies have assessed associations between exposures to HP, PAA, and AA, and work-related symptoms in these settings. METHODS: In 2018, we performed a health and exposure assessment at a hospital where a sporicidal product consisting of HP, PAA, and AA, was used as the primary cleaner on hospital surfaces. We collected 56 personal and mobile air samples for HP, PAA, and AA on participants while they performed their regular cleaning duties; collected area samples for HP (n = 28), PAA (n = 28), and AA (n = 70) in multiple hospital locations where cleaning was performed; and administered a postshift survey to assess eye, skin, and upper and lower airway symptoms that occurred cross-shift or in the previous 4 weeks. RESULTS: Full-shift exposure levels for HP (range: <3-559 ppb), PAA (range: <0.2-8 ppb), and AA (range: <5-915 ppb) were all below US occupational exposure limits. We observed positive associations (p < 0.05) between shift, departmental average, and departmental 95th percentile exposures to HP, PAA, and AA vapors, and work-related acute (cross-shift) and chronic (previous 4 weeks) eye, upper airway, and lower airway symptoms after adjusting for age, gender, smoking status, use of other cleaning products containing sensitizers and irritants, allergic status, and stress. CONCLUSIONS: Our observations of work-related upper and lower airway symptoms among hospital workers exposed to vapors from a sporicidal product containing HP, PAA, and AA indicate a need for a combination of engineering, administrative, and PPE controls to reduce exposure. Additionally, alternative nonchemical disinfection technologies should be further investigated as a means to simultaneously reduce healthcare workers' exposure to disinfectants while also minimizing costly healthcare-acquired infections. |
Use of 3-Dimensional Printers in Educational Settings: The Need for Awareness of the Effects of Printer Temperature and Filament Type on Contaminant Releases
Stefaniak AB , Bowers LN , Cottrell G , Erdem E , Knepp AK , Martin S , Pretty J , Duling MG , Arnold ED , Wilson Z , Krider B , LeBouf RF , Virji MA , Sirinterlikci A . J Chem Health Saf 2021 28 (6) 444-456 Material extrusion-type fused filament fabrication (FFF) 3-D printing is a valuable tool for education. During FFF 3-D printing, thermal degradation of the polymer releases small particles and chemicals, many of which are hazardous to human health. In this study, particle and chemical emissions from 10 different filaments made from virgin (never printed) and recycled polymers were used to print the same object at the polymer manufacturer's recommended nozzle temperature ("normal") and at a temperature higher than recommended ("hot") to simulate the real-world scenarios of a person intentionally or unknowingly printing on a machine with a changed setting. Emissions were evaluated in a college teaching laboratory using standard sampling and analytical methods. From mobility sizer measurements, particle number-based emission rates were 81 times higher; the proportion of ultrafine particles (diameter <100 nm) were 4% higher, and median particle sizes were a factor of 2 smaller for hot-temperature prints compared with normal-temperature prints (all p-values <0.05). There was no difference in emission characteristics between recycled and virgin acrylonitrile butadiene styrene and polylactic acid polymer filaments. Reducing contaminant release from FFF 3-D printers in educational settings can be achieved using the hierarchy of controls: (1) elimination/substitution (e.g., training students on principles of prevention-through-design, limiting the use of higher emitting polymer when possible); (2) engineering controls (e.g., using local exhaust ventilation to directly remove contaminants at the printer or isolating the printer from students); (3) administrative controls such as password protecting printer settings and establishing and enforcing adherence to a standard operating procedure based on a proper risk assessment for the setup and use (e.g., limiting the use of temperatures higher than those specified for the filaments used); and (4) maintenance of printers. |
Large-Format Additive Manufacturing and Machining Using High-Melt-Temperature Polymers. Part I: Real-Time Particulate and Gas-Phase Emissions
Stefaniak AB , Bowers LN , Martin SB Jr , Hammond DR , Ham JE , Wells JR , Fortner AR , Knepp AK , du Preez S , Pretty JR , Roberts JL , du Plessis JL , Schmidt A , Duling MG , Bader A , Virji MA . J Chem Health Saf 2021 28 (3) 190-200 The literature on emissions during material extrusion additive manufacturing with 3-D printers is expanding; however, there is a paucity of data for large-format additive manufacturing (LFAM) machines that can extrude high-melt-temperature polymers. Emissions from two LFAM machines were monitored during extrusion of six polymers: acrylonitrile butadiene styrene (ABS), polycarbonate (PC), high-melt-temperature polysulfone (PSU), poly(ether sulfone) (PESU), polyphenylene sulfide (PPS), and Ultem (poly(ether imide)). Particle number, total volatile organic compound (TVOC), carbon monoxide (CO), and carbon dioxide (CO(2)) concentrations were monitored in real-time. Particle emission rate values (no./min) were as follows: ABS (1.7 × 10(11) to 7.7 × 10(13)), PC (5.2 × 10(11) to 3.6 × 10(13)), Ultem (5.7 × 10(12) to 3.1 × 10(13)), PPS (4.6 × 10(11) to 6.2 × 10(12)), PSU (1.5 × 10(12) to 3.4 × 10(13)), and PESU (2.0 to 5.0 × 10(13)). For print jobs where the mass of extruded polymer was known, particle yield values (g(-1) extruded) were as follows: ABS (4.5 × 10(8) to 2.9 × 10(11)), PC (1.0 × 10(9) to 1.7 × 10(11)), PSU (5.1 × 10(9) to 1.2 × 10(11)), and PESU (0.8 × 10(11) to 1.7 × 10(11)). TVOC emission yields ranged from 0.005 mg/g extruded (PESU) to 0.7 mg/g extruded (ABS). The use of wall-mounted exhaust ventilation fans was insufficient to completely remove airborne particulate and TVOC from the print room. Real-time CO monitoring was not a useful marker of particulate and TVOC emission profiles for Ultem, PPS, or PSU. Average CO(2) and particle concentrations were moderately correlated (r (s) = 0.76) for PC polymer. Extrusion of ABS, PC, and four high-melt-temperature polymers by LFAM machines released particulate and TVOC at levels that could warrant consideration of engineering controls. LFAM particle emission yields for some polymers were similar to those of common desktop-scale 3-D printers. |
Large-Format Additive Manufacturing and Machining Using High-Melt-Temperature Polymers. Part II: Characterization of Particles and Gases
Stefaniak AB , Bowers LN , Martin SB Jr , Hammond DR , Ham JE , Wells JR , Fortner AR , Knepp AK , du Preez S , Pretty JR , Roberts JL , du Plessis JL , Schmidt A , Duling MG , Bader A , Virji MA . J Chem Health Saf 2021 28 (4) 268-278 Extrusion of high-melt-temperature polymers on large-format additive manufacturing (LFAM) machines releases particles and gases, though there is no data describing their physical and chemical characteristics. Emissions from two LFAM machines were monitored during extrusion of acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) polymers as well as high-melt-temperature Ultem (poly(ether imide)), polysulfone (PSU), poly(ether sulfone) (PESU), and polyphenylene sulfide (PPS) polymers. Filter samples of particles were collected for quantification of elements and bisphenol A and S (BPA, BPS) and visualization of morphology. Individual gases were quantified on substance-specific media. Aerosol sampling demonstrated that concentrations of elements were generally low for all polymers, with a maximum of 1.6 mg/m(3) for iron during extrusion of Ultem. BPA, an endocrine disruptor, was released into air during extrusion of PC (range: 0.4 ± 0.1 to 21.3 ± 5.3 μg/m(3)). BPA and BPS (also an endocrine disruptor) were released into air during extrusion of PESU (BPA, 2.0-8.7 μg/m(3); BPS, 0.03-0.07 μg/m(3)). Work surfaces and printed parts were contaminated with BPA (<8-587 ng/100 cm(2)) and BPS (<0.22-2.5 ng/100 cm(2)). Gas-phase sampling quantified low levels of respiratory irritants (phenol, SO(2), toluene, xylenes), possible or known asthmagens (caprolactam, methyl methacrylate, 4-oxopentanal, styrene), and possible occupational carcinogens (benzene, formaldehyde, acetaldehyde) in air. Characteristics of particles and gases released by high-melt-temperature polymers during LFAM varied, which indicated the need for polymer-specific exposure and risk assessments. The presence of BPA and BPS on surfaces revealed a previously unrecognized source of dermal exposure for additive manufacturing workers using PC and PESU polymers. |
Characterization of cleaning and disinfection product use, glove use, and skin disorders by healthcare occupations in a Midwestern healthcare facility
Kobos L , Anderson K , Kurth L , Liang X , Groth CP , England L , Laney AS , Virji MA . Buildings 2022 12 (12) 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 23 or 45 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. 2022 by the authors. |
Editorial: Investigating exposures and respiratory health in coffee workers
Virji MA , Cummings KJ , Cox-Ganser JM . Front Public Health 2022 10 1026430 Workers in the coffee industry face a variety of inhalational hazards. These range from predominantly organic dust, endotoxin, and green and castor bean allergen exposures in the primary processing factories to dusts, gases, and vapors including α-diketones in coffee production facilities (1–5). Previously documented respiratory health effects include symptoms such as wheeze, cough, and dyspnea, bronchial hyperresponsiveness, reduced spirometric parameters, and chronic lung diseases including asthma and obliterative bronchiolitis (OB) (3, 5–10). Some of these studies are decades old, while some are notable for small size and limited exposure assessments. In this special issue of Frontiers in Public Health on “Investigating exposures and respiratory health in coffee workers”, a series of articles explores in detail the exposures, emissions, engineering controls, and health consequences across the contemporary coffee industry by describing studies of primary processing in 16 factories in two African countries and coffee production in 17 facilities in the United States. |
Potential for exposure to particles and gases throughout vat photopolymerization additive manufacturing processes
Bowers LN , Stefaniak AB , Knepp AK , LeBouf RF , Martin SBJr , Ranpara AC , Burns DA , Virji MA . Buildings (Basel) 2022 12 (8) Vat photopolymerization (VP), a type of additive manufacturing process that cures resin to build objects, can emit potentially hazardous particles and gases. We evaluated two VP technologies, stereolithography (SLA) and digital light processing (DLP), in three separate environmental chambers to understand task-based impacts on indoor air quality. Airborne particles, total volatile organic compounds (TVOCs), and/or specific volatile organic compounds (VOCs) were monitored during each task to evaluate their exposure potential. Regardless of duration, all tasks released particles and organic gases, though concentrations varied between SLA and DLP processes and among tasks. Maximum particle concentrations reached 1200 #/cm3 and some aerosols contained potentially hazardous elements such as barium, chromium, and manganese. TVOC concentrations were highest for the isopropyl alcohol (IPA) rinsing, soaking, and drying post-processing tasks (up to 36.8 mg/m3), lowest for the resin pouring pre-printing, printing, and resin recovery post-printing tasks (up to 0.1 mg/m3), and intermediate for the curing post-processing task (up to 3 mg/m3). Individual VOCs included, among others, the potential occupational carcinogen acetaldehyde and the immune sensitizer 2-hydroxypropyl methacrylate (pouring, printing, recovery, and curing tasks). Careful consideration of all tasks is important for the development of strategies to minimize indoor air pollution and exposure potential from VP processes. © 2022 by the authors. |
Decrements in lung function and respiratory abnormalities associated with exposure to diacetyl and 2,3-pentanedione in coffee production workers
Virji MA , Fechter-Leggett ED , Groth CP , Liang X , Blackley BH , Stanton ML , LeBouf RF , Harvey RR , Bailey RL , Cummings KJ , Cox-Ganser JM . Front Public Health 2022 10 966374 Coffee production workers are exposed to complex mixtures of gases, dust, and vapors, including the known respiratory toxins, diacetyl, and 2,3-pentanedione, which occur naturally during coffee roasting and are also present in flavorings used to flavor coffee. This study evaluated the associations of these two -diketones with lung function measures in coffee production workers. Workers completed questionnaires, and their lung function was assessed by spirometry and impulse oscillometry (IOS). Personal exposures to diacetyl, 2,3-pentanedione, and their sum (Sum(DA+PD)) were assigned to participants, and metrics of the highest 95th percentile (P95), cumulative, and average exposure were calculated. Linear and logistic regression models for continuous and binary/polytomous outcomes, respectively, were used to explore exposure-response relationships adjusting for age, body mass index, tenure, height, sex, smoking status, race, or allergic status. Decrements in percent predicted forced expiratory volume in 1 second (ppFEV(1)) and forced vital capacity (ppFVC) were associated with the highest-P95 exposures to 2,3-pentanedione and Sum(DA+PD). Among flavoring workers, larger decrements in ppFEV(1) and ppFVC were associated with highest-P95 exposures to diacetyl, 2,3-pentanedione, and Sum(DA+PD). Abnormal FEV(1), FVC, and restrictive spirometric patterns were associated with the highest-P95, cumulative, and average exposures for all -diketone metrics; some of these associations were also present among flavoring and non-flavoring workers. The combined category of small and peripheral airways plus small and large airways abnormalities on IOS had elevated odds for highest-P95 exposure to -diketones. These results may be affected by the small sample size, few cases of abnormal spirometry, and the healthy worker effect. Associations between lung function abnormalities and exposure to -diketones suggest it may be prudent to consider exposure controls in both flavoring and non-flavoring settings. |
Determinants of task-based exposures to alpha-diketones in coffee roasting and packaging facilities using a Bayesian model averaging approach
Blackley BH , Groth CP , Cox-Ganser JM , Fortner AR , LeBouf RF , Liang X , Virji MA . Front Public Health 2022 10 878907 ![]() Coffee production workers can be exposed to inhalational hazards including alpha-diketones such as diacetyl and 2,3-pentanedione. Exposure to diacetyl is associated with the development of occupational lung disease, including obliterative bronchiolitis, a rare and irreversible lung disease. We aimed to identify determinants contributing to task-based exposures to diacetyl and 2,3-pentanedione at 17 U.S. coffee production facilities. We collected 606 personal short-term task-based samples including roasting (n = 189), grinding (n = 74), packaging (n = 203), quality control (QC, n = 44), flavoring (n = 15), and miscellaneous production/caf tasks (n = 81), and analyzed for diacetyl and 2,3-pentanedione in accordance with the modified OSHA Method 1013/1016. We also collected instantaneous activity-based (n = 296) and source (n = 312) samples using evacuated canisters. Information on sample-level and process-level determinants relating to production scale, sources of alpha-diketones, and engineering controls was collected. Bayesian mixed-effect regression models accounting for censored data were fit for overall data (all tasks) and specific tasks. Notable determinants identified in univariate analyses were used to fit all plausible models in multiple regression analysis which were summarized using a Bayesian model averaging method. Grinding, flavoring, packaging, and production tasks with ground coffee were associated with the highest short-term and instantaneous-activity exposures for both analytes. Highest instantaneous-sources of diacetyl and 2,3-pentanedione included ground coffee, flavored coffee, liquid flavorings, and off-gassing coffee bins or packages. Determinants contributing to higher exposures to both analytes in all task models included sum of all open storage sources and average percent of coffee production as ground coffee. Additionally, flavoring ground coffee and flavoring during survey contributed to notably higher exposures for both analytes in most, but not all task groups. Alternatively, general exhaust ventilation contributed to lower exposures in all but two models. Additionally, among facilities that flavored, local exhaust ventilation during flavoring processes contributed to lower 2,3-pentanedione exposures during grinding and packaging tasks. Coffee production facilities can consider implementing additional exposure controls for processes, sources, and task-based determinants associated with higher exposures to diacetyl and 2,3-pentanedione, such as isolating, enclosing, and directly exhausting grinders, flavoring mixers, and open storage of off-gassing whole bean and ground coffee, to reduce exposures and minimize risks for lung disease among workers. |
Comparison of product safety data sheet ingredient lists with skin irritants and sensitizers present in a convenience sample of light-curing resins used in additive manufacturing
Bowers LN , Ranpara AC , Roach KA , Knepp AK , Arnold ED , Stefaniak AB , Virji MA . Regul Toxicol Pharmacol 2022 133 105198 Material jetting and vat photopolymerization additive manufacturing (AM) processes use liquid resins to build objects. These resins can contain skin irritants and/or sensitizers but product safety data sheets (SDSs) might not declare all ingredients. We characterized elemental and organic skin irritants and sensitizers present in 39 commercial products; evaluated the influence of resin manufacturer, system, color, and AM process type on the presence of irritants and sensitizers; and compared product SDSs to results. Among all products, analyses identified 23 irritant elements, 54 irritant organic substances, 22 sensitizing elements, and 23 sensitizing organic substances; SDSs listed 3, 9, 4, and 6 of these ingredients, respectively. Per product, the number and total mass (an indicator of potential dermal loading) of ingredients varied: five to 17 irritant elements (8.32-4756.65mg/kg), one to 17 irritant organics (3273 to 356,000mg/kg), four to 17 sensitizing elements (8.27-4755.63mg/kg), and one to seven sensitizing organics (15-382,170mg/kg). Median numbers and concentrations of irritants and sensitizers were significantly influenced by resin system and AM process type. The presence of undeclared irritants and sensitizers in these resins supports the need for more complete information on product SDSs for comprehensive dermal risk assessments. |
Efficacy of dental evacuation systems for aerosol exposure mitigation in dental clinic settings.
Blackley BH , Anderson KR , Panagakos F , Chipps T , Virji MA . J Occup Environ Hyg 2022 19 (5) 1-14 Dental personnel are ranked among the highest risk occupations for exposure to SARS-CoV-2 due to their close proximity to the patient's mouth and many aerosol generating procedures encountered in dental practice. One method to reduce aerosols in dental settings is the use of intraoral evacuation systems. Intraoral evacuation systems are placed directly into a patient's mouth and maintain a dry field during procedures by capturing liquid and aerosols. Although multiple intraoral dental evacuation systems are commercially available, the efficacy of these systems is not well understood. The objectives of this study were to evaluate the efficacy of four dental evacuation systems at mitigating aerosol exposures during simulated ultrasonic scaling and crown preparation procedures. We conducted real-time respirable (PM(4)) and thoracic (PM(10)) aerosol sampling during ultrasonic scaling and crown preparation procedures while using four commercially available evacuation systems: a high-volume evacuator (HVE) and three alternative intraoral systems (A, B, C). Four trials were conducted for each system. Respirable and thoracic mass concentrations were measured during procedures at three locations including (1) near the breathing zone (BZ) of the dentist, (2) edge of the dental operatory room approximately 0.9 m away from the mannequin mouth, and (3) hallway supply cabinet located approximately 1.5 m away from the mannequin mouth. Respirable and thoracic mass concentrations measured during each procedure were compared with background concentrations measured in each respective location. Use of System A or HVE reduced thoracic (System A) and respirable (HVE) mass concentrations near the dentist's BZ to median background concentrations most often during the ultrasonic scaling procedure. During the crown preparation, use of System B or HVE reduced thoracic (System B) and respirable (HVE or System B) near the dentist's BZ to median background concentrations most often. Although some differences in efficacy were noted during each procedure and aerosol size fraction, the difference in median mass concentrations among evacuation systems was minimal, ranging from 0.01 to 1.48 µg/m(3) across both procedures and aerosol size fractions. |
Two-year follow-up of exposure, engineering controls, respiratory protection and respiratory health among workers at an indium-tin oxide (ITO) production and reclamation facility
Harvey RR , Virji MA , Blackley BH , Stanton ML , Trapnell BC , Carey B , Healey T , Cummings KJ . Occup Environ Med 2022 79 (8) 550-556 OBJECTIVES: To determine whether engineering controls and respiratory protection had measurable short-term impact on indium exposure and respiratory health among current indium-tin oxide production and reclamation facility workers. METHODS: We documented engineering controls implemented following our 2012 evaluation and recorded respirator use in 2012 and 2014. We measured respirable indium (In(resp)) and plasma indium (In(P)) in 2012 and 2014, and calculated change in In(resp) (∆In(resp)) and In(P) (∆In(P)) by the 13 departments. We assessed symptoms, lung function, serum biomarkers of interstitial lung disease (Krebs von den Lungen (KL)-6 and surfactant protein (SP)-D) and chest high-resolution CT at both time points and evaluated workers who participated in both 2012 and 2014 for changes in health outcomes (new, worsened or improved). RESULTS: Engineering controls included installation of local exhaust ventilation in both grinding departments (Rotary and Planar) and isolation of the Reclaim department. Respiratory protection increased in most (77%) departments. ∆In(P) and ∆In(resp) often changed in parallel by department. Among 62 workers participating in both 2012 and 2014, 18 (29%) had new or worsening chest symptoms and 2 (3%) had functional decline in lung function or radiographic progression, but average KL-6 and SP-D concentrations decreased, and no cases of clinical indium lung disease were recognised. CONCLUSIONS: Increased engineering controls and respiratory protection can lead to decreased In(resp), In(P) and biomarkers of interstitial lung disease among workers in 2 years. Ongoing medical monitoring of indium-exposed workers to confirm the longer-term effectiveness of preventive measures is warranted. |
Influence of E-Liquid Humectants, Nicotine, and Flavorings on Aerosol Particle Size Distribution and Implications for Modeling Respiratory Deposition.
Stefaniak AB , Ranpara AC , Virji MA , LeBouf RF . Front Public Health 2022 10 782068 Electronic cigarette, or vaping, products are used to heat an e-liquid to form an aerosol (liquid droplets suspended in gas) that the user inhales; a portion of this aerosol deposits in their respiratory tract and the remainder is exhaled, thereby potentially creating opportunity for secondhand exposure to bystanders (e.g., in homes, automobiles, and workplaces). Particle size, a critical factor in respiratory deposition (and therefore potential for secondhand exposure), could be influenced by e-liquid composition. Hence, the purposes of this study were to (1) test the influence of laboratory-prepared e-liquid composition [ratio of propylene glycol (PG) to vegetable glycerin (VG) humectants, nicotine, and flavorings] on particle size distribution and (2) model respiratory dosimetry. All e-liquids were aerosolized using a second-generation reference e-cigarette. We measured particle size distribution based on mass using a low-flow cascade impactor (LFCI) and size distribution based on number using real-time mobility sizers. Mass median aerodynamic diameters (MMADs) of aerosol from e-liquids that contained only humectants were significantly larger compared with e-liquids that contained flavorings or nicotine (p = 0.005). Humectant ratio significantly influenced MMADs; all aerosols from e-liquids prepared with 70:30 PG:VG were significantly larger compared with e-liquids prepared with 30:70 PG:VG (p = 0.017). In contrast to the LFCI approach, the high dilution and sampling flow rate of a fast mobility particle sizer strongly influenced particle size measurements (i.e., all calculated MMAD values were < 75 nm). Dosimetry modeling using LFCI data indicated that a portion of inhaled particles will deposit throughout the respiratory tract, though statistical differences in aerosol MMADs among e-liquid formulations did not translate into large differences in deposition estimates. A portion of inhaled aerosol will be exhaled and could be a source for secondhand exposure. Use of laboratory-prepared e-liquids and a reference e-cigarette to standardize aerosol generation and a LFCI to measure particle size distribution without dilution represents an improved method to characterize physical properties of volatile aerosol particles and permitted determination of MMAD values more representative of e-cigarette aerosol in situ, which in turn, can help to improve dose modeling for users and bystanders. |
A Strategy for Field Evaluations of Exposures and Respiratory Health of Workers at Small- to Medium-Sized Coffee Facilities
Virji MA , Cummings KJ , Cox-Ganser JM . Front Public Health 2021 9 705225 Coffee production is a global industry with roasteries throughout the world. Workers in this industry are exposed to complex mixtures of gases, dusts, and vapors including carbon monoxide, carbon dioxide, coffee dust, allergens, alpha-diketones, and other volatile organic compounds (VOCs). Adverse respiratory health outcomes such as respiratory symptoms, reduced pulmonary function, asthma, and obliterative bronchiolitis can occur among exposed workers. In response to health hazard evaluations requests received from 17 small- to medium-sized coffee facilities across the United States, the National Institute for Occupational Safety and Health conducted investigations during 2016-2017 to understand the burden of respiratory abnormalities, exposure characteristics, relationships between exposures and respiratory effects, and opportunities for exposure mitigation. Full-shift, task-based, and instantaneous personal and area air samples for diacetyl, 2,3-pentanedione and other VOCs were collected, and engineering controls were evaluated. Medical evaluations included questionnaire, spirometry, impulse oscillometry, and fractional exhaled nitric oxide. Exposure and health assessments were conducted using standardized tools and approaches, which enabled pooling data for aggregate analysis. The pooled data provided a larger population to better address the requestors' concern of the effect of exposure to alpha-diketones on the respiratory heath of coffee workers. This paper describes the rationale for the exposure and health assessment strategy, the approach used to achieve the study objectives, and its advantages and limitations. |
Towards sustainable additive manufacturing: The need for awareness of particle and vapor releases during polymer recycling, making filament, and fused filament fabrication 3-D printing
Stefaniak AB , Bowers LN , Cottrell G , Erdem E , Knepp AK , Martin SB Jr , Pretty J , Duling MG , Arnold ED , Wilson Z , Krider B , Fortner AR , LeBouf RF , Virji MA , Sirinterlikci A . Resour Conserv Recycl 2022 176 Fused filament fabrication three-dimensional (FFF 3-D) printing is thought to be environmentally sustainable; however, significant amounts of waste can be generated from this technology. One way to improve its sustainability is via distributed recycling of plastics in homes, schools, and libraries to create feedstock filament for printing. Risks from exposures incurred during recycling and reuse of plastics has not been incorporated into life cycle assessments. This study characterized contaminant releases from virgin (unextruded) and recycled plastics from filament production through FFF 3-D printing. Waste polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) plastics were recycled to create filament; virgin PLA, ABS, high and low density polyethylenes, high impact polystyrene, and polypropylene pellets were also extruded into filament. The release of particles and chemicals into school classrooms was evaluated using standard industrial hygiene methodologies. All tasks released particles that contained hazardous metals (e.g., manganese) and with size capable of depositing in the gas exchange region of the lung, i.e., granulation of waste PLA and ABS (667 to 714 nm) and filament making (608 to 711 nm) and FFF 3-D printing (616 to 731 nm) with waste and virgin plastics. All tasks released vapors, including respiratory irritants and potential carcinogens (benzene and formaldehyde), mucus membrane irritants (acetone, xylenes, ethylbenzene, and methyl methacrylate), and asthmagens (styrene, multiple carbonyl compounds). These data are useful for incorporating risks of exposure to hazardous contaminants in future life cycle evaluations to demonstrate the sustainability and circular economy potential of FFF 3-D printing in distributed spaces. © 2021 |
HLA-DPB1 E69 genotype and exposure in beryllium sensitisation and disease
Crooks J , Mroz MM , VanDyke M , McGrath A , Schuler C , McCanlies EC , Virji MA , Rosenman KD , Rossman M , Rice C , Monos D , Fingerlin TE , Maier LA . Occup Environ Med 2021 79 (2) 120-126 OBJECTIVES: Human leukocyte antigen-DP beta 1 (HLA-DPB1) with a glutamic acid at the 69th position of the ß chain (E69) genotype and inhalational beryllium exposure individually contribute to risk of chronic beryllium disease (CBD) and beryllium sensitisation (BeS) in exposed individuals. This retrospective nested case-control study assessed the contribution of genetics and exposure in the development of BeS and CBD. METHODS: Workers with BeS (n=444), CBD (n=449) and beryllium-exposed controls (n=890) were enrolled from studies conducted at nuclear weapons and primary beryllium manufacturing facilities. Lifetime-average beryllium exposure estimates were based on workers' job questionnaires and historical and industrial hygienist exposure estimates, blinded to genotype and case status. Genotyping was performed using sequence-specific primer-PCR. Logistic regression models were developed allowing for over-dispersion, adjusting for workforce, race, sex and ethnicity. RESULTS: Having no E69 alleles was associated with lower odds of both CBD and BeS; every additional E69 allele increased odds for CBD and BeS. Increasing exposure was associated with lower odds of BeS. CBD was not associated with exposure as compared to controls, yet the per cent of individuals with CBD versus BeS increased with increasing exposure. No evidence of a gene-by-exposure interaction was found for CBD or BeS. CONCLUSIONS: Risk of CBD increases with E69 allele frequency and increasing exposure, although no gene by environment interaction was found. A decreased risk of BeS with increasing exposure and lack of exposure response in CBD cases may be due to the limitations of reconstructed exposure estimates. Although reducing exposure may not prevent BeS, it may reduce CBD and the associated health effects, especially in those carrying E69 alleles. |
Assessment of home care aides' respiratory exposure to total volatile organic compounds and chlorine during simulated bathroom cleaning: An experimental design with conventional and "green" products
Lindberg JE , Quinn MM , Gore RJ , Galligan CJ , Sama SR , Sheikh NN , Markkanen PK , Parker-Vega A , Karlsson ND , LeBouf RF , Virji MA . J Occup Environ Hyg 2021 18 (6) 1-12 Home care (HC) aide visits to clients' homes often involve cleaning and disinfecting (C&D) bathrooms. Some ingredients in C&D household products are associated with respiratory illness, including sodium hypochlorite (bleach) and quaternary ammonium compounds (quats). "Green" products may be safer for the environment, however there are limited quantitative evaluations of their respiratory risks. This study assessed airborne concentrations and time profiles of total volatile organic compounds (TVOC) and chlorine generated during typical bathroom cleaning performed by aides using conventional and green products. Aides performed cleaning tasks in a simulated residential bathroom constructed in an environmental air sampling laboratory. A balanced experimental design involved each aide coming to the lab for four visits during which she performed two 20-min cleaning sessions using one of three C&D products (bleach-based, 1-5% sodium hypochlorite by weight; quats-based, 0.1-1% by weight quaternary ammonium compounds; and "green," 0.05% by weight thymol, a component of botanical thyme oil) or distilled water as a control. TVOC and chlorine direct reading instruments were attached to aides with sample inlets located in the breathing zone. Ten-second averages of TVOC and chlorine gas concentrations and instantaneous peak concentrations were recorded for the sessions' duration. TVOC concentrations by methods of C&D application (spraying, streaming, wiping) also were evaluated. The study completed 169 air sampling sessions with 22 aides. The quats-based product generated more than twice the average TVOC concentrations (mean = 1,210 ppb) than the bleach-based (mean = 593 ppb) or green (mean = 498 ppb) products. Each product generated TVOC concentrations that rose rapidly within the first few minutes of application. Spraying produced the highest TVOC exposures, wiping the lowest. Thirteen aides (65%) experienced peak chlorine exposures above the OSHA PEL ceiling limit (1 ppm) when using the bleach-based product. HC aides may experience respiratory hazards from use of conventional or green C&D products formulated with bleach or other respiratory irritants and sprayed in small, poorly ventilated spaces typical of bathrooms. Spraying should be avoided. |
Particle transfer and adherence to human skin compared with cotton glove and pre-moistened polyvinyl alcohol exposure sampling substrates
Stefaniak AB , Wade EE , Lawrence RB , Arnold ED , Virji MA . J Environ Sci Health A Tox Hazard Subst Environ Eng 2021 56 (5) 1-12 Measurement of skin exposure to particles using interception (e.g., cotton gloves) and removal (e.g., wiping) sampling techniques could be inaccurate because these substrates do not have the same topography and adhesion characteristics as skin. The objective of this study was to compare particle transfer and adherence to cotton gloves, cotton gloves with artificial sebum, and a pre-moistened polyvinyl alcohol (PVA) material with bare human skin (fingertip, palm). Experiments were performed with aluminum oxide powder under standardized conditions for three types of surfaces touched, applied loads, contact times, and powder mass levels. In the final mixed model, the fixed effects of substrate, surface type, applied load, and powder mass and their significant two-way interaction terms explained 71% (transfer) and 74% (adherence) of the observed total variance in measurements. For particle mass transfer, compared with bare skin, bias was -77% (cotton glove with sebum) to +197% (PVA material) and for adherence bias ranged from -40% (cotton glove) to +428% (PVA material), which indicated under- and over-sampling by these substrates, respectively. Dermal exposure assessment would benefit from sampling substrates that better reflect human skin characteristics and more accurately estimate exposures. Mischaracterization of dermal exposure has important implications for exposure and risk assessment. |
Peak inhalation exposure metrics used in occupational epidemiologic and exposure studies
Virji MA , Kurth L . Front Public Health 2021 8 611693 Peak exposures are of concern because they can potentially overwhelm normal defense mechanisms and induce adverse health effects. Metrics of peak exposure have been used in epidemiologic and exposure studies, but consensus is lacking on its definition. The relevant characteristics of peak exposure are dependent upon exposure patterns, biokinetics of exposure, and disease mechanisms. The objective of this review was to summarize the use of peak metrics in epidemiologic and exposure studies. A comprehensive search of Medline, Embase, Web of Science, and NIOSHTIC-2 databases was conducted using keywords related to peak exposures. The retrieved references were reviewed and selected for indexing if they included a peak metric and met additional criteria. Information on health outcomes and peak exposure metrics was extracted from each reference. A total of 1,215 epidemiologic or exposure references were identified, of which 182 were indexed and summarized. For the 72 epidemiologic studies, the health outcomes most frequently evaluated were: chronic respiratory effects, cancer and acute respiratory symptoms. Exposures were frequently assessed using task-based and full-shift time-integrated methods, qualitative methods, and real-time instruments. Peak exposure summary metrics included the presence or absence of a peak event, highest exposure intensity and frequency greater than a target. Peak metrics in the 110 exposure studies most frequently included highest exposure intensity, average short-duration intensity, and graphical presentation of the real-time data (plots). This review provides a framework for considering biologically relevant peak exposure metrics for epidemiologic and exposure studies to help inform risk assessment and exposure mitigation. |
Exposures and emissions in coffee roasting facilities and cafes: diacetyl, 2,3-pentanedione, and other volatile organic compounds
LeBouf RF , Blackley BH , Fortner AR , Stanton M , Martin SB , Groth CP , McClelland TL , Duling MG , Burns DA , Ranpara A , Edwards N , Fedan KB , Bailey RL , Cummings KJ , Nett RJ , Cox-Ganser JM , Virji MA . Front Public Health 2020 8 561740 Roasted coffee and many coffee flavorings emit volatile organic compounds (VOCs) including diacetyl and 2,3-pentanedione. Exposures to VOCs during roasting, packaging, grinding, and flavoring coffee can negatively impact the respiratory health of workers. Inhalational exposures to diacetyl and 2,3-pentanedione can cause obliterative bronchiolitis. This study summarizes exposures to and emissions of VOCs in 17 coffee roasting and packaging facilities that included 10 cafés. We collected 415 personal and 760 area full-shift, and 606 personal task-based air samples for diacetyl, 2,3-pentanedione, 2,3-hexanedione, and acetoin using silica gel tubes. We also collected 296 instantaneous activity and 312 instantaneous source air measurements for 18 VOCs using evacuated canisters. The highest personal full-shift exposure in part per billion (ppb) to diacetyl [geometric mean (GM) 21 ppb; 95th percentile (P95) 79 ppb] and 2,3-pentanedione (GM 15 ppb; P95 52 ppb) were measured for production workers in flavored coffee production areas. These workers also had the highest percentage of measurements above the NIOSH Recommended Exposure Limit (REL) for diacetyl (95%) and 2,3-pentanedione (77%). Personal exposures to diacetyl (GM 0.9 ppb; P95 6.0 ppb) and 2,3-pentanedione (GM 0.7 ppb; P95 4.4 ppb) were the lowest for non-production workers of facilities that did not flavor coffee. Job groups with the highest personal full-shift exposures to diacetyl and 2,3-pentanedione were flavoring workers (GM 34 and 38 ppb), packaging workers (GM 27 and 19 ppb) and grinder operator (GM 26 and 22 ppb), respectively, in flavored coffee facilities, and packaging workers (GM 8.0 and 4.4 ppb) and production workers (GM 6.3 and 4.6 ppb) in non-flavored coffee facilities. Baristas in cafés had mean full-shift exposures below the RELs (GM 4.1 ppb diacetyl; GM 4.6 ppb 2,3-pentanedione). The tasks, activities, and sources associated with flavoring in flavored coffee facilities and grinding in non-flavored coffee facilities, had some of the highest GM and P95 estimates for both diacetyl and 2,3-pentanedione. Controlling emissions at grinding machines and flavoring areas and isolating higher exposure areas (e.g., flavoring, grinding, and packaging areas) from the main production space and from administrative or non-production spaces is essential for maintaining exposure control. |
Evidence for environmental-human microbiota transfer at a manufacturing facility with novel work-related respiratory disease
Wu BG , Kapoor B , Cummings KJ , Stanton ML , Nett RJ , Kreiss K , Abraham JL , Colby TV , Franko AD , Green FHY , Sanyal S , Clemente JC , Gao Z , Coffre M , Meyn P , Heguy A , Li Y , Sulaiman I , Borbet TC , Koralov SB , Tallaksen RJ , Wendland D , Bachelder VD , Boylstein RJ , Park JH , Cox-Ganser JM , Virji MA , Crawford JA , Edwards NT , Veillette M , Duchaine C , Warren K , Lundeen S , Blaser MJ , Segal LN . Am J Respir Crit Care Med 2020 202 (12) 1678-1688 INTRODUCTION: Workers' exposure to metalworking fluid (MWF) has been associated with respiratory disease. As part of a public health investigation of a manufacturing facility, we performed paired environmental and human sampling to evaluate cross-pollination of microbes between environment and host and possible effects on lung pathology present among workers. METHODS: Workplace environmental microbiota was evaluated in air and MWF samples. Human microbiota was evaluated in lung tissue samples from workers with respiratory symptoms found to have lymphocytic bronchiolitis and alveolar ductitis with B-cell follicles and emphysema, lung tissue controls, and in skin, nasal and oral samples from 302 workers from different areas of the facility. In vitro effects of MWF exposure on murine B-cells were assessed. RESULTS: Increased similarity of microbial composition was found between MWF samples and lung tissue samples of case workers compared to controls. Among workers in different locations within the facility, those that worked in machine shop area had skin, nasal and oral microbiota more closely related to the microbiota present in MWF samples. Lung samples from four index cases, and skin and nasal samples from workers in machine shop area were enriched with Pseudomonas, the dominant taxa in MWF. Exposure to used MWF stimulated murine B-cell proliferation in vitro, a hallmark cell subtype found in pathology of index cases. CONCLUSIONS: Evaluation of a manufacturing facility with a cluster of workers with respiratory disease supports cross-pollination of microbes from MWF to humans and suggests the potential for exposure to these microbes to be a health hazard. |
Workplace indoor environmental quality and asthma-related outcomes in healthcare workers
Rollins SM , Su FC , Liang X , Humann MJ , Stefaniak AB , LeBouf RF , Stanton ML , Virji MA , Henneberger PK . Am J Ind Med 2020 63 (5) 417-428 BACKGROUND: Asthma-related health outcomes are known to be associated with indoor moisture and renovations. The objective of this study was to estimate the frequency of these indoor environmental quality (IEQ) factors in healthcare facilities and their association with asthma-related outcomes among workers. METHODS: New York City healthcare workers (n = 2030) were surveyed regarding asthma-related symptoms, and moisture and renovation factors at work and at home during the last 12 months. Questions for workplace moisture addressed water damage (WD), mold growth (MG), and mold odor (MO), while for renovations they addressed painting (P), floor renovations (FR), and wall renovations (WR). Regression models were fit to examine associations between work and home IEQ factors and multiple asthma-related outcomes. RESULTS: Reports of any moisture (n = 728, 36%) and renovations (n = 1412, 70%) at work were common. Workplace risk factors for asthma-related outcomes included the moisture categories of WD by itself, WD with MO (without MG), and WD with MG and MO, and the renovation category with the three factors P, FR, and WR. Reports of home IEQ factors were less frequent and less likely to be associated with health outcomes. Data analyses suggested that MG and/or MO at work and at home had a synergistic effect on the additive scale with a symptom-based algorithm for bronchial hyperresponsiveness. CONCLUSIONS: The current study determined that moisture and renovation factors are common in healthcare facilities, potentially putting workers at risk for asthma-related outcomes. More research is needed to confirm these results, especially prospective studies. |
Work-related adverse respiratory health outcomes at a machine manufacturing facility with a cluster of bronchiolitis, alveolar ductitis and emphysema (BADE)
Cummings KJ , Stanton ML , Kreiss K , Boylstein RJ , Park JH , Cox-Ganser JM , Virji MA , Edwards NT , Segal LN , Blaser MJ , Weissman DN , Nett RJ . Occup Environ Med 2020 77 (6) 386-392 OBJECTIVES: Four machine manufacturing facility workers had a novel occupational lung disease of uncertain aetiology characterised by lymphocytic bronchiolitis, alveolar ductitis and emphysema (BADE). We aimed to evaluate current workers' respiratory health in relation to job category and relative exposure to endotoxin, which is aerosolised from in-use metalworking fluid. METHODS: We offered a questionnaire and spirometry at baseline and 3.5 year follow-up. Endotoxin exposures were quantified for 16 production and non-production job groups. Forced expiratory volume in one second (FEV1) decline >/=10% was considered excessive. We examined SMRs compared with US adults, adjusted prevalence ratios (aPRs) for health outcomes by endotoxin exposure tertiles and predictors of excessive FEV1 decline. RESULTS: Among 388 (89%) baseline participants, SMRs were elevated for wheeze (2.5 (95% CI 2.1 to 3.0)), but not obstruction (0.5 (95% CI 0.3 to 1.1)). Mean endotoxin exposures (range: 0.09-28.4 EU/m(3)) were highest for machine shop jobs. Higher exposure was associated with exertional dyspnea (aPR=2.8 (95% CI 1.4 to 5.7)), but not lung function. Of 250 (64%) follow-up participants, 11 (4%) had excessive FEV1 decline (range: 403-2074 mL); 10 worked in production. Wheeze (aPR=3.6 (95% CI 1.1 to 12.1)) and medium (1.3-7.5 EU/m(3)) endotoxin exposure (aPR=10.5 (95% CI 1.3 to 83.1)) at baseline were associated with excessive decline. One production worker with excessive decline had BADE on subsequent lung biopsy. CONCLUSIONS: Lung function loss and BADE were associated with production work. Relationships with relative endotoxin exposure indicate work-related adverse respiratory health outcomes beyond the sentinel disease cluster, including an incident BADE case. Until causative factors and effective preventive strategies for BADE are determined, exposure minimisation and medical surveillance of affected workforces are recommended. |
The burden of respiratory abnormalities among workers at coffee roasting and packaging facilities
Harvey RR , Fechter-Leggett ED , Bailey RL , Edwards NT , Fedan KB , Virji MA , Nett RJ , Cox-Ganser JM , Cummings KJ . Front Public Health 2020 8 5 Introduction: Respiratory hazards in the coffee roasting and packaging industry can include asthmagens such as green coffee bean and other dust and alpha-diketones such as diacetyl and 2,3-pentanedione that can occur naturally from roasting coffee or artificially from addition of flavoring to coffee. We sought to describe the burden of respiratory abnormalities among workers at 17 coffee roasting and packaging facilities. Methods: We completed medical surveys at 17 coffee roasting and packaging facilities that included interviewer-administered questionnaires and pulmonary function testing. We summarized work-related symptoms, diagnoses, and spirometry testing results among all participants. We compared health outcomes between participants who worked near flavoring and who did not. Results: Participants most commonly reported nose and eye symptoms, and wheeze, with a work-related pattern for some. Symptoms and pulmonary function tests were consistent with work-related asthma in some participants. About 5% of workers had abnormal spirometry and most improved after bronchodilator. Health outcomes were similar between employees who worked near flavoring and who did not, except employees who worked near flavoring reported more chronic bronchitis and ever receiving a diagnosis of asthma than those who did not work near flavoring. Conclusion: The symptoms and patterns likely represent overlapping health effects of different respiratory hazards, including green coffee bean and other dust that can contribute to work-related asthma, and diacetyl and 2,3-pentanedione that can contribute to obliterative bronchiolitis. Healthcare providers and occupational health and safety practitioners should be aware that workers at coffee roasting and packaging facilities are potentially at risk for occupational lung diseases. |
Particle and organic vapor emissions from children's 3-D pen and 3-D printer toys
Yi J , Duling MG , Bowers LN , Knepp AK , LeBouf RF , Nurkiewicz TR , Ranpara A , Luxton T , Martin SB Jr , Burns DA , Peloquin DM , Baumann EJ , Virji MA , Stefaniak AB . Inhal Toxicol 2019 31 1-14 Objective: Fused filament fabrication "3-dimensional (3-D)" printing has expanded beyond the workplace to 3-D printers and pens for use by children as toys to create objects.Materials and methods: Emissions from two brands of toy 3-D pens and one brand of toy 3-D printer were characterized in a 0.6 m(3) chamber (particle number, size, elemental composition; concentrations of individual and total volatile organic compounds (TVOC)). The effects of print parameters on these emission metrics were evaluated using mixed-effects models. Emissions data were used to model particle lung deposition and TVOC exposure potential.Results: Geometric mean particle yields (10(6)-10(10) particles/g printed) and sizes (30-300 nm) and TVOC yields (<detectable to 590 microg TVOC/g printed) for the toys were similar to those from 3-D printers used in workplaces. Metal emissions included manganese (1.6-92.3 ng/g printed) and lead (0.13-1.2 ng/g printed). Among toys, extruder nozzle conditions (diameter, temperature) and filament (type, color, and extrusion speed) significantly influenced particle and TVOC emissions. Dose modeling indicated that emitted particles would deposit in the lung alveoli of children. Exposure modeling indicated that TVOC concentration from use of a single toy would be 1-31 microg/m(3) in a classroom and 3-154 microg/m(3) in a residential living room.Discussion: Potential exists for inhalation of organic vapors and metal-containing particles during use of these toys.Conclusions: If deemed appropriate, e.g. where multiple toys are used in a poorly ventilated area or a toy is positioned near a child's breathing zone, control technologies should be implemented to reduce emissions and exposure risk. |
Work tasks as determinants of respirable and inhalable indium exposure among workers at an indium-tin oxide production and reclamation facility
Hawley Blackley B , Cummings KJ , Stanton M , Stefaniak AB , Gibbs JL , Park JY , Harvey RR , Virji MA . Ann Work Expo Health 2019 64 (2) 175-184 Increased global demand for touch screens, photovoltaics, and optoelectronics has resulted in an increase in the production of indium-tin oxide (ITO). Occupational exposure to indium compounds is associated with the development of indium lung disease. Although many previous epidemiologic investigations highlight an excess of lung abnormalities in workplaces where ITO is produced, few assessments of occupational exposure to respirable and inhalable indium are reported to date. The objective of this study was to identify the determinants of respirable and inhalable indium at an ITO production facility to target exposure interventions. In 2012 and 2014, we conducted exposure assessments at an ITO production facility and collected full-shift personal respirable (n = 159) and inhalable (n = 57) indium samples. We also observed workers and recorded information on task duration and location, materials used, and use of personal protective equipment (PPE). Tasks (n = 121) recorded in task diaries were categorized into 40 similar task groups using the Advanced REACH Tool and process-related information. Mixed-effects models were fit separately for log-transformed respirable and inhalable indium, with random effect of subject and fixed effects of task groups. Overall, respirable and inhalable indium measurements ranged from 0.1 to 796.6 microg m-3 and 1.6 to 10 585.7 microg m-3, respectively, and were highly correlated with Spearman correlation coefficient of 0.90. The final model for respirable indium explained 36.3% of total variance and identified sanding, powder transfer tasks in reclaim, powder transfer tasks in refinery, handling indium materials, and liquid transfer tasks in ITO production as tasks associated with increased respirable indium exposure. The final model for inhalable indium explained 24.6% of total variance and included powder transfer tasks in ITO production, cleaning cylinder or tile, and handling indium material tasks. Tasks identified as strong predictors of full-shift exposure to respirable and inhalable indium can guide the use of engineering, administrative, and PPE controls designed to mitigate occupational exposure to indium. Moreover, since the tasks were aligned with REACH activities, results from this study can also be used to inform REACH activity scenarios. |
Associations of metrics of peak inhalation exposure and skin exposure indices with beryllium sensitization at a beryllium manufacturing facility
Virji MA , Schuler CR , Cox-Ganser J , Stanton ML , Kent MS , Kreiss K , Stefaniak AB . Ann Work Expo Health 2019 63 (8) 856-869 OBJECTIVES: Peak beryllium inhalation exposures and exposure to the skin may be relevant for developing beryllium sensitization (BeS). The objective of this study was to identify risk factors associated with BeS to inform the prevention of sensitization, and the development of chronic beryllium disease (CBD). METHODS: In a survey of short-term workers employed at a primary beryllium manufacturing facility between the years 1994-1999, 264 participants completed a questionnaire and were tested for BeS. A range of qualitative and quantitative peak inhalation metrics and skin exposure indices were created using: personal full-shift beryllium exposure measurements, 15 min to 24 h process-specific task and area exposure measurements, glove measurements as indicator of skin exposure, process-upset information gleaned from historical reports, and self-reported information on exposure events. Hierarchical clustering was conducted to systematically group participants based on similarity of patterns of 16 exposure variables. The associations of the exposure metrics with BeS and self-reported skin symptoms (in work areas processing beryllium salts as well as in other work areas) were evaluated using correlation analysis, log-binomial and logistic regression models with splines. RESULTS: Metrics of peak inhalation exposure, indices of skin exposure, and using material containing beryllium salts were significantly associated with skin symptoms and BeS; skin symptoms were a strong predictor of BeS. However, in this cohort, we could not tease apart the independent effects of skin exposure from inhalation exposure, as these exposures occurred simultaneously and were highly correlated. Hierarchical clustering identified groups of participants with unique patterns of exposure characteristics resulting in different prevalence of BeS and skin symptoms. A cluster with high skin exposure index and use of material containing beryllium salts had the highest prevalence of BeS and self-reported skin symptoms, followed by a cluster with high inhalation and skin exposure index and a very small fraction of jobs in which beryllium salts were used. A cluster with low inhalation and skin exposure and no workers using beryllium salts had no cases of BeS. CONCLUSION: Multiple pathways and types of exposure were associated with BeS and may be important for informing BeS prevention. Prevention efforts should focus on controlling airborne beryllium exposures with attention to peaks, use of process characteristics (e.g. the likelihood of upset conditions to design interventions) minimize skin exposure to beryllium particles, and in particular, eliminate skin contact with beryllium salts to interrupt potential exposure pathways for BeS risk. |
Severe lung disease characterized by lymphocytic bronchiolitis, alveolar ductitis, and emphysema (BADE) in industrial machine-manufacturing workers
Cummings KJ , Stanton ML , Nett RJ , Segal LN , Kreiss K , Abraham JL , Colby TV , Franko AD , Green FHY , Sanyal S , Tallaksen RJ , Wendland D , Bachelder VD , Boylstein RJ , Park JH , Cox-Ganser JM , Virji MA , Crawford JA , Green BJ , LeBouf RF , Blaser MJ , Weissman DN . Am J Ind Med 2019 62 (11) 927-937 BACKGROUND: A cluster of severe lung disease occurred at a manufacturing facility making industrial machines. We aimed to describe disease features and workplace exposures. METHODS: Clinical, functional, radiologic, and histopathologic features were characterized. Airborne concentrations of thoracic aerosol, metalworking fluid, endotoxin, metals, and volatile organic compounds were measured. Facility airflow was assessed using tracer gas. Process fluids were examined using culture, polymerase chain reaction, and 16S ribosomal RNA sequencing. RESULTS: Five previously healthy male never-smokers, ages 27 to 50, developed chest symptoms from 1995 to 2012 while working in the facility's production areas. Patients had an insidious onset of cough, wheeze, and exertional dyspnea; airflow obstruction (mean FEV1 = 44% predicted) and reduced diffusing capacity (mean = 53% predicted); and radiologic centrilobular emphysema. Lung tissue demonstrated a unique pattern of bronchiolitis and alveolar ductitis with B-cell follicles lacking germinal centers, and significant emphysema for never-smokers. All had chronic dyspnea, three had a progressive functional decline, and one underwent lung transplantation. Patients reported no unusual nonoccupational exposures. No cases were identified among nonproduction workers or in the community. Endotoxin concentrations were elevated in two air samples; otherwise, exposures were below occupational limits. Air flowed from areas where machining occurred to other production areas. Metalworking fluid primarily grew Pseudomonas pseudoalcaligenes and lacked mycobacterial DNA, but 16S analysis revealed more complex bacterial communities. CONCLUSION: This cluster indicates a previously unrecognized occupational lung disease of yet uncertain etiology that should be considered in manufacturing workers (particularly never-smokers) with airflow obstruction and centrilobular emphysema. Investigation of additional cases in other settings could clarify the cause and guide prevention. |
Peaks, Means, and Determinants of Real-Time TVOC Exposures Associated with Cleaning and Disinfecting Tasks in Healthcare Settings.
Virji MA , Liang X , Su FC , LeBouf RF , Stefaniak AB , Stanton ML , Henneberger PK , Houseman EA . Ann Work Expo Health 2019 63 (7) 759-772 ![]() ![]() Cleaning and disinfecting tasks and product use are associated with elevated prevalence of asthma and respiratory symptoms among healthcare workers; however, the levels of exposure that pose a health risk remain unclear. The objective of this study was to estimate the peak, average, and determinants of real-time total volatile organic compound (TVOC) exposure associated with cleaning tasks and product-use. TVOC exposures were measured using monitors equipped with a photoionization detector (PID). A simple correction factor was applied to the real-time measurements, calculated as a ratio of the full-shift average TVOC concentrations from a time-integrated canister and the PID sample, for each sample pair. During sampling, auxiliary information, e.g. tasks, products used, engineering controls, was recorded on standardized data collection forms at 5-min intervals. Five-minute averaged air measurements (n = 10 276) from 129 time-series comprising 92 workers and four hospitals were used to model the determinants of exposures. The statistical model simultaneously accounted for censored data and non-stationary autocorrelation and was fit using Markov-Chain Monte Carlo within a Bayesian context. Log-transformed corrected concentrations (cTVOC) were modeled, with the fixed-effects of tasks and covariates, that were systematically gathered during sampling, and random effect of person-day. The model-predicted geometric mean (GM) cTVOC concentrations ranged from 387 parts per billion (ppb) for the task of using a product containing formaldehyde in laboratories to 2091 ppb for the task of using skin wipes containing quaternary ammonium compounds, with a GM of 925 ppb when no products were used. Peak exposures quantified as the 95th percentile of 15-min averages for these tasks ranged from 3172 to 17 360 ppb. Peak and GM task exposures varied by occupation and hospital unit. In the multiple regression model, use of sprays was associated with increasing exposures, while presence of local exhaust ventilation, large room volume, and automatic sterilizer use were associated with decreasing exposures. A detailed understanding of factors affecting TVOC exposure can inform targeted interventions to reduce exposures and can be used in epidemiologic studies as metrics of short-duration peak exposures. |
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