This retrospective cohort epidemiological study investigated the relative risks of hearing loss associated with ototoxicants in combination with noise exposure. Utilizing United States Department of Defense (DoD) industrial hygiene and hearing conservation data, this research expanded on a 2020 study conducted on Tinker Air Force Base (AFB), Oklahoma, applying a similar methodology to Hill AFB, Utah, adding 893 evaluated individuals. Grouped into twelve exposure combinations with a minimum of 3 years of exposure duration, the study assessed various hearing loss indicators, including DoD Significant Threshold Shift (STS) and National Institute for Occupational Safety and Health (NIOSH) STS. Ototoxic substances consistently elevated relative risk (RR) compared to noise-only exposure groups, but none reached significance at the 95% confidence level. Incorporating Hill AFB to findings from Tinker AFB ( = 2,372) revealed exposure groups with a RR greater than one for developing a NIOSH STS were significant at the 95% confidence level, with the greatest RR coming from the metal, solvent, continuous noise exposure group in the left ear at 2,000 Hz (RR = 2.25; 1.96-2.57). Logistic regression modeling identified age and audiogram duration between first and last audiogram (as a surrogate for duration of exposure) as significant independent variables for hearing loss indicator development prediction.

Miners face a variety of respiratory hazards on the job, including exposure to respirable crystalline silica (RCS), which can lead to adverse health outcomes such as silicosis and lung cancer-both potentially fatal lung diseases. Infrared spectrometry offers the possibility of portable end-of-shift quantification of RCS at mine sites. However, some mine dusts contain minerals that may interfere with this quantification method, as their infrared absorbance bands overlap with those of silica. To evaluate the impact of such interferences, potential mineral interferants were identified in the geologies of 27 metal mines using the United States Geological Survey and Mindat.org databases. These mines were selected based on historically high RCS levels, as evidenced in the Mine Safety and Health Administration (MSHA) field-sampling database, and on the number of employees potentially exposed. The significance of 44 potential interferants was evaluated using Fourier Transform Infrared spectroscopy (FT-IR), by measuring their absorbance per unit mass in the α-quartz doublet region of the spectrum (816-767 cm). The extent to which each mineral interfered with this region was quantified as its integrated absorbance relative to RCS. This quantification of interference provides data critical for the timely and portable quantification of RCS in mine dusts. Of the 44 specimens analyzed, three (goethite, azurite and actinolite), which are not mentioned in the standard infrared methods for quantification of RCS, were found to interfere with a magnitude of 10% or more. Despite being commonly mentioned as interferants in the literature, the feldspars Albite and Anorthite did not interfere with a magnitude of 10% or more.

Silver-based biocides applied in fabric-based mouth- and nose-covering face masks require characterization due to the potential toxic effects of silver to which users may be exposed. In the absence of reliable silver release data in realistic usage conditions, current safety assessment of face masks relies on a safe-by-design principle. To contribute to the refinement of specifications of safe face masks, types of particulate silver biocides actively applied in face masks on the market were identified and characterized. Ultramicrotomy followed by scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy (STEM-EDX) analysis showed that a wide variety of silver-based biocides were applied. This includes metallic silver nanoparticles (NPs), silver salts in NP form, silver ion exchangers, and notably, various silver nanocomposites with other particulate materials such as synthetic amorphous silica (SAS), TiO, and ZnO. These composites are added to face masks to combine different modes of biocidal action or to facilitate gradual silver release, thereby extending biocidal activity. In five out of seven silver-containing masks, silver-containing NPs were identified on the surface of fibers. Additionally, significant numbers of other NPs (SAS, TiO) were found coating the fiber surfaces. Sizes of silver-containing NPs ranged from 3 to 200 nm across all masks, with the large majority of particles below 50 nm. These findings imply that for safety assessment, no-adverse effect levels of all incorporated compounds should be taken into account and that the effects of co-exposure to multiple compounds should be considered. The completion of particle release studies, exposure assessments, and regulatory oversight of face masks is recommended.

Workers frequently struggle to acquire, maintain, and use personal protective equipment (PPE) during infectious disease outbreaks. Strategic PPE distribution, guidance, and interventions can help address these challenges, but the effectiveness of these measures depends on timely characterization of how these challenges manifest across the U.S. workforce-data which no U.S. public health surveillance system currently provides. This article describes a mechanism of generating such data by using a machine learning model to detect various PPE concerns in workplace safety complaints submitted to the U.S. Occupational Safety and Health Administration (OSHA). A publicly available dataset of 78,770 OSHA complaints received during the COVID-19 pandemic was used to assess the feasibility of this approach. Results demonstrate that these OSHA complaints contained a substantial variety and number of PPE concerns, and that a machine learning model trained on these data was capable of detecting three types of PPE concerns with at least 90% precision and 90% recall: unavailable or inaccessible PPE, lack of PPE use among workers, and inadequate enforcement of PPE use. Furthermore, analyses of ML-facilitated detections were shown to elucidate national and industry-specific trends in worker PPE concerns. Although further development is needed to accurately detect a broader set of PPE concerns, the results of this study suggest that machine learning can help efficiently repurpose OSHA complaints to generate insightful real-time data on worker PPE concerns during future outbreaks.

This study assessed whether self-rated physical and mental work demands were associated with cognition among older working adults and whether their effects were dependent. The cross-sectional sample consisted of 6,377 working older adults using the Health and Retirement Study in 2004. Self-rated work demands were summarized from four questions about the frequency of mental or physical demands in the respondent's current job. Cognition was assessed using a subset of the Telephone Interview for Cognitive Status. Multivariable linear regression assessed the associations and additive interaction between physical and mental work demands and cognition, adjusted for age, sex, race, education, and practice effect. Independently, higher physical work demands were associated with poorer cognition (change per one unit increase: 0.50, 95% CI: 0.36, 0.65), and higher mental work demands were associated with better cognition (change per one unit increase: -0.31, 95% CI: -0.44, -0.19). The effect of one work demand measure became more negative as the level of the other increased (Beta for interaction = -0.23, 95% CI: -0.43, -0.03). A one-point increase in mental work demands was associated with 0.79 (95% CI: 0.51, 1.08) points higher cognition score when physical work demands were lowest, but was not associated with cognition when physical work demands were highest (0.11, 95% CI: -0.26, 0.48). The highest predicted cognition score was for the highest mental and lowest physical work demands. Results were robust to additional adjustment for health and behavior covariates. The associations of self-rated mental and physical work demands on cognition are dependent. Future studies should strongly consider examining interactions to capture the range of work demand effects.

Farming is a noisy occupation, resulting in a high prevalence of hearing loss among agricultural workers. The aim of this study was to improve the accuracy of an automatic algorithm designed to cluster individual sound events into tasks. This work is part of the HearSafe Study, which aimed to increase agricultural workers' use of hearing protection devices by providing personalized information on hazardous noise to workers. Participants in the study interacted with the HearSafe System: a small sound level meter, a website, and an algorithm to associate noise with tasks. They wore the sound level meter that recorded loud (≥ 80 dBA) sound "events," their location, and audio clips. They interacted with the website to view where and when participants were exposed to hazardous noises during the day. To simplify interpretation, an algorithm clustered individual sound events into tasks based on their proximity in time and location. The system's effectiveness hinges on the accuracy of this clustering algorithm. In Phase I, the accuracy was determined using parameters for time between events (2, 5, and 10 min) and distances between tasks (5, 9, and 18 m). In Phase II, the algorithm was refined to account for pauses in work and riding on equipment. Researchers manually clustered events into tasks by listening to the audio clips. Algorithm accuracy was measured as the percentage of events matching the manual clustering. The automating accuracy was improved from 57% with the base algorithm to 87% with the most accurate algorithm ( = 0.02; 10 min between events, 9 m average distance between tasks, and added the condition to combining consecutive tasks that were within 9 m of each other). Increased accuracy in identifying noisy tasks will improve the efficacy of the HearSafe System to communicate when and where use of hearing protection devices are needed among agricultural workers.

There is a growing interest in the health benefits of sun exposure, yet evidence linking sun exposure to cardiovascular disease (CVD) risk is limited. This study aimed to investigate the associations between sun exposure and CVD. This study utilized data from the National Health and Nutrition Examination Survey (NHANES), assessing sun exposure through behaviors such as staying in the shade, wearing long-sleeved shirts, using sunscreen, and time spent outdoors on weekdays and non-workdays. CVD was defined by self-reported physician-diagnosed heart disease (including congestive heart failure, coronary heart disease, angina, heart attack, and stroke). Multivariate logistic regression was applied. A bidirectional two-sample Mendelian randomization (MR) was also conducted to assess the causal relationship. Effect sizes were expressed as odds ratios (ORs) with a 95% confidence interval (CI). The study showed that staying less in shade decreased the risk of CVD (never in model 3: OR = 0.72, 95% CI= 0.54-0.96,  = 0.03). Additionally, CVD was influenced by using sunscreen (always in model 3: OR = 0.69, 95% CI= 0.50-0.94,  = 0.02) and spending time outdoors (model 3: OR = 0.96, 95% CI= 0.93-0.99,  = 0.01). Wearing long-sleeved shirts did not affect on the occurrence of CVD. However, no evidence of a causal relationship between sun exposure and CVD using MR analysis was observed. While the NHANES data suggested sun exposure was associated with a reduced risk of CVD, the MR analysis did not establish a causal link, suggesting further research is needed to understand this relationship.

Oncology nurses are routinely exposed to antineoplastic agents through skin absorption or inhalation of airborne agents when administering drugs intravenously. Although safe infusion devices aimed at preventing the hazardous disconnection of empty bags were developed, none of them are completely closed systems per National Institute for Occupational Safety and Health (NIOSH) guidelines. The authors evaluated a closed system administration device developed to prevent exposure of healthcare professionals to cytotoxic drugs during their administration. System components were assembled in various scenarios mimicking intravenous drug administration and then tested in a sealed chamber connected to a gas analyzer. The concentration of 70% isopropanol vapors (as a drug surrogate) was measured continuously in the chamber. The analysis showed no detectable increase in isopropanol vapor concentration in the sealed chamber compared to baseline levels over the course of the tasks, indicating that no leaks of 70% isopropanol occurred when the closed system administration devices were used. Furthermore, the results remained the same regardless of the number of connection cycles the products had undergone, or whether they were newly manufactured or at the simulated end of their shelf-life. This study showed that the use of a closed administration system can minimize the risk of exposure of healthcare professionals to hazardous drugs and potentially reduce environmental contamination.

During most of the COVID-19 pandemic, N95 respirators were in short supply, creating a need for alternative solutions to protect healthcare workers and others from infection. The current pilot study was conducted to determine whether using a KN95 respirator with a custom respirator frame would be an effective alternative to an N95 respirator. Using the Bellus3D Dental Pro application on an iPhone, a 3D face scan was obtained for six adult volunteers (three women, three men), and a custom mask frame was 3D printed in gray resin. Next, a PortaCount Fit Tester was used to test the fit of a KN95 respirator, a KN95 respirator with the custom mask frame, and an N95 respirator. The three respirator configurations were compared for overall fit and fit during four day-to-day movements (bending over, talking, and moving the head side to side or up and down). Fit factor values could range from 1-200, and a value of 100 was considered the minimum to meet established safety specifications. The mean (SD) overall fit factor was 12.1 (1.8) for the KN95 respirator, 195.4 (11.2) for the KN95 respirator with the custom mask frame, and 170.0 (38.3) for the N95 respirator. Differences were found between the three configurations for all outcomes (all < .004). Post hoc comparisons indicated differences between the KN95 respirator and KN95 respirator with the custom mask frame for all outcomes (all < .02) and between the KN95 respirator with the custom mask frame and N95 respirator for moving the head side to side ( = .04). Results of the pilot current study suggested using a KN95 respirator with a custom mask frame significantly improved the fit factor to meet existing safety specifications. In the future, healthcare workers and organizations should consider this configuration as an effective alternative to N95 respirators.

This article describes how Hermann J. Muller attempted to persuade the editor of the journal to obtain a review of his book on eugenics entitled: Muller sent the editor of , James McKeen Cattell, a letter soliciting a review of his forthcoming eugenics book. Muller's letter is of historical significance for several reasons. It highlights how Muller characterized his own standing on the issue with respect to his geneticist colleagues, especially those in the United States. Of even greater importance is the striking lack of transparency that Muller employed in attempting to persuade the editor, not only to publish a review of his book, but also to select the reviewer(s) from a list of suggested geneticists/biologists he provided. The Muller letter is significant since it shows that Muller was deceptive in his communication with the editor. He failed to disclose his personal and professional relationships with each of the six proposed reviewers and their long histories of support and advocacy for eugenics-based societal policies. The present example of Muller's ethical improbity adds to a substantial listing of similar actions that are linked both to his propensity for inappropriate self-promotion and ideological advocacy as seen in activities dealing with eugenics, chemical and radiological risk assessment, hereditary and cancer risk assessment, health physics practices, and the development of secondary school biological curriculum. The current paper gives a rare glimpse into ethics and bias in the scientific community and raises a series of new challenges to the culture of science and its dependence on honesty and transparency. While Muller may be appreciated as a scientist of great talent and achievement, he also displayed personal failings that undercut the integrity of scientific research.

Firefighters are exposed to various carcinogenic substances during firefighting tasks, but also in the maintenance of firefighting personal protective equipment (PPE). Due to multiple exposures to chemical agents via different exposure routes, the International Agency for Research on Cancer (IARC) categorized the firefighting occupation as Group 1 - carcinogenic to humans. Decontamination methods have been found to play an important role in reducing firefighter chemical exposures. Unfortunately, decontamination techniques are insufficient in removing carcinogenic substances from PPE. This study aimed to evaluate decontamination methods for firefighter turnout gear. Using various techniques, the cleaning efficiency of 18 polycyclic aromatic hydrocarbons (PAHs) from turnout gear coats contaminated during firefighting exercises was measured. For turnout gear coats ( = 40), decontamination methods used were conventional aqueous laundering (AL) and its combination with advanced hydrogen peroxide treatment (HO) or ozone treatment in a chamber (O). In addition, the cleaning efficiencies of advanced liquid carbon dioxide (LCO) and the ozone laundry system (LO) were measured. Results show that when the conventional AL water wash temperature increased from 40 to 60 °C, cleaning efficiencies did not significantly increase. Cleaning efficiencies in outer layers of coats were 63% and 60%, respectively. The results in outer layers of AL combined with O and HO techniques showed cleaning efficiencies 84% and 42%, respectively. Cleaning efficiency with LO and with the fully advanced LCO technique demonstrated cleaning efficiency 71% and 74%, respectively. LCO was the most advanced, especially in the middle layers, yielding a cleaning efficiency of 84% while other techniques in the middle layers reached a maximum efficiency 24%. The cleaning efficiency of all methods indicated approximately 20-30% lower cleaning efficiency for high molecular weight (HMW) PAHs than for low molecular weight (LMW) PAHs. The results of this study emphasized the importance of improving conventional AL and the advantage of the LCO method in enhancing cleaning efficiency.

Asbestos was used in certain packing products for much of the twentieth century. The objective of this study was to characterize exposure from working with and around chrysotile-containing packing during valve repair and overhaul to better understand the exposure potential of career pipefitters and other tradesmen, as well as bystanders and household contacts. Airborne fiber and chrysotile concentrations during packing (20.91-62.77% chrysotile) replacement were measured during standard and nonstandard work tasks involving valve repair and overhaul, cleanup, and clothes handling. Packing replacement was performed on 21 valves by a career engineer at a facility with no mechanical ventilation. Out of 126 air samples, 56 had airborne fiber concentrations above the limit of detection using phase contrast microscopy (PCM) analysis and were subsequently analyzed by transmission electron microscopy (TEM); chrysotile was detected in 21 of the 56 samples. Packing replacement in 16 valves in succession without additional manipulation (such as sanding or compressed air blowout) resulted in a task-based personal average concentration of 0.0378 f/cc, PCM-equivalent asbestos-specific fibers or PCME, while one valve replacement event with compressed air use resulted in an average concentration of 0 f/cc, PCME, and compressed air and sanding combined resulted in an average concentration of 0.0018 f/cc, PCME. Task-based personal sampling during cleanup resulted in concentrations averaging 0.0047 to 0.0162 f/cc, PCME; no chrysotile was detected in task-based close bystander area samples, nor in any samples collected during clothes handling and post-handling cleanup. Regression analysis showed no correlation between PCM concentrations and measured size-fractionated and total airborne particulate matter concentrations. The results indicated that for packing replacement, including work on 16 valves in succession, lack of mechanical ventilation, and nonstandard work practices, all partial-shift and task-based average personal and area airborne fiber concentrations were below the OSHA 8-hr Time-Weighted Average (TWA) Permissible Exposure Limit (PEL) of 0.1 f/cc and 30-min TWA Excursion Limit (EL) for asbestos of 1 f/cc, consistent with previous literature.

The present assessment was undertaken to develop an understanding of the occurrence and status of peer review with biological science-oriented journals in the first few decades of the 20th century. This research was centered around whether peer review would have been a realistic expectation/demand for that era for experimentally oriented biologists. The analysis indicates that the peer review process in 17 major biologically oriented journals from the United States was created principally in the early decades of the 20th century. These journals included those relating to both botanical (e.g., plant physiology, plant pathology) and zoological (e.g., biochemistry, physiology, immunology, genetics) research domains. These findings represent the first integrative evaluation of experimentally oriented biological journals concerning their historical peer-review activities. The information is based on summarized articles in the journals concerning their peer-review process, similar assessments provided by related professional societies that published the journals, as well as the preserved papers of some journal editors, which included actual peer-review documents of that era. This assessment indicates that formal peer review was commonly practiced amongst many of the leading biologically oriented US-based journals during that era. These are useful in evaluating the publication strategy of Hermann J. Muller as it relates to the avoidance of peer review regarding his novel claim to have induced gene mutations via exposure to X-rays.

A pilot-scale simulation study of tea tree oil (TTO) airborne dispersion in a household setting was conducted to evaluate emissions of volatile organic compounds (VOCs), including terpenes ("TerVOCs"), and various particle size classes while using an ultrasonic diffuser ("Survey 1") and a heat diffuser ("Survey 2"). Of the VOCs evaluated, isopropyl alcohol and p-dichlorobenzene were detected in one or more surveys, and their measured concentrations were below relevant exposure limits. Total VOC levels were measured above background (approximately 200 to 300 ppb) by one to two orders of magnitude during Surveys 1 and 2, respectively. TerVOC levels collected during Survey 1 were below applicable exposure limits. Air concentrations of α-pinene, α-terpinene, α-terpinolene, γ-terpinene, and p-isopropyltoluene for samples collected during Survey 2, however, exceeded long-term derived no-effect levels (DNELs) for worker and/or general populations, and α-pinene measurements exceeded the long-term exposure limit established by the European Commission through the INDEX project. TerVOC concentrations detected during Survey 2 were generally an order of magnitude higher than samples collected during Survey 1. This study is the first peer-reviewed publication known to the authors to report data collected during essential oil diffuser operations in a residential setting in the United States.

Understanding the health concerns linked to long-term low-dose ionizing radiation exposure is essential to creating safety protocols and protective gear for healthcare workers. Despite reports on the biological effects of low-dose chronic or protracted exposure to ionizing radiation, its association with long-term health effects remains unclear. To examine this, the authors obtained and tested peripheral blood samples from control participants (Healthcare workers not involved in radiation-based work ( = 21) and healthcare professionals ( = 25) receiving low-dose radiation over time as part of their occupation. Change in case with alignment to control, for early and delayed DNA damage was measured using the formation of gamma H2AX (γ-H2AX), micronucleus (MN), and () expression changes. These biomarkers were compared to cumulative registered doses, as determined by the individuals' personal dosimetry records using thermoluminescent dosimeters (TLDs). The mean γ-H2AX foci frequency estimated in blood lymphocytes among the control group was 0.05 ± 0.01, and in healthcare workers was 0.04 ± 0.01 ( > 0.05). The mean of MN aberration frequency standard error (SE) in control was 0.001 ± 0.001 and in healthcare workers was 0.005 ± 0.002 ( < 0.0001). Similarly, expression in healthcare workers increased by 7% when compared to the control group. The cumulative registered dose in the healthcare workers' monitoring device varied between 0 and 21 mSv with an average of 3.65 mSv. A weak correlation was observed between the registered TLD dose and biomarker- γ-H2AX (R=0.0123), MN (R= 0.0011), and expression (R= 0.0006). The study results suggest a lack of dose-dependent increase in DNA damage as evaluated by γ-H2AX, MN formation, and expression change among healthcare workers exposed to chronic low-dose radiation. Moreover, the observed range of these biomarkers was not significantly different from the baseline data established from apparently healthy non-radiation workers of the same population. Assay sensitivity and healthcare worker adherence to safety procedures to decrease exposures are two probable factors for the lack of correlation between the registered dose and that of DNA damage.

South Africa's commercially planted timber is mainly from the non-native genera (acacia), (eucalyptus), and (pine). These trees are popular because they are fast-growing, stress-tolerant, and commercially profitable. During timber processing, woodworkers can be exposed to wood dust through inhalation or dermal contact. Occupational exposure limits (OELs) have been developed to help protect workers against adverse health effects from overexposure to wood dust. In South Africa, the Regulations for Hazardous Chemical Agents of 2021 (RHCA 2021) list an inhalable OEL-maximum limit (ML) for wood dust from oak, beech, birch, mahogany, teak, and walnut (2 mg/m), and OEL-restricted limit (RL) for all other species (5 mg/m), but do not refer to acacia, eucalyptus, or pine. Due to their popularity as commercial plantation timber, these tree types may pose occupational health risks to South African woodworkers. This systematic review investigates the health effects associated with occupational exposure to acacia, eucalyptus, and pine wood dust and discusses the implications for South African OELs. A systematic literature search was conducted using EBSCO Academic Search Complete, PubMed Central, ScienceDirect, Scopus, and Web of Science. Overall, 67 articles were included in the study. The prevalence of skin and respiratory sensitization in exposed workers was <10%. Adverse dermal effects included non-allergic skin sensitivity, allergic contact dermatitis, palpable erythema, and pigmentation loss. Respiratory effects included allergic alveolitis, vocal cord dysfunction, airway inflammatory reactions, higher prevalence of respiratory symptoms, and occupational asthma. Carcinogenicity was not reported. Exposure concentrations exceeded current South African (5 mg/m, all species) and international inhalable wood dust OELs. Based on case reports, epidemiological and toxicological data, exposure studies, and current regulations, the authors propose an inhalable 8-hr time-weighted average-OEL-ML of 2 mg/m with dermal and respiratory sensitization notations for acacia, eucalyptus, and pine wood dust. To date, only has been investigated as an occupational health hazard. To create representative OELs for occupational wood dust exposure, occupational epidemiological and toxicological studies for other common timbers should be undertaken.