It is well known that excessive intake of metals can affect human health. Metals, such as chromium and nickel, have different toxic properties depending on their chemical form and water solubility. The solubility and toxicity mechanisms of particles containing these metals are unknown when they are inhaled into the body. In this study, we investigated the experimental conditions of water dialysis using a polycarbonate membrane filter to collect particles and a scanning electron microscope (SEM) for observation. Water dialysis is a method for determining the composition and mixture state of water-soluble and -insoluble components of individual particles in the atmospheric environment field. The following experimental procedures were suggested as the most suitable for water dialysis: 1) applying a carbon coating to the polycarbonate membrane filter (thickness of approximately 5 nm before collecting particles and approximately 2 nm after collecting particles); 2) after observation with a SEM, a hydrophilic treatment was applied to the specimen stub fixed with a piece of the filter. The stub was soaked in ultrapure water for approximately two hours; 3) subsequently, the stub was dried in a desiccator for more than 24 hours. Following these treatments, the same areas on the filter that were analyzed before the dialysis were observed with the SEM again.

Inattentiveness is a human trait that cannot be entirely avoided. However, even minor lapses can result in significant accidents. This study aimed to elucidate the characteristics of occupational accidents stemming from inattention. A total of 31,496 cases of occupational accidents occurring in 2017 were analyzed. Individual cases suspected to be caused by inattention were classified based on industry, accident type, age, context, type of inattention, and targets that should have been attended to. Consequently, we found that, first, fall accidents were largely attributed to inattention. Second, accidents caused by inattention tended to increase with age. Third, inattention on occupational accidents was caused mainly by the limitation of attentional capacity rather than that of sustained attention. Fourth, the context and target regarding occupational accidents caused by inattention were industry-specific. Accordingly, we emphasize the importance of understanding the characteristics of inattention in the workplace and propose safety measures based on the results.

To assess the risk of spontaneous ignition in the utilization of fine powdered coal within a plant, we conducted an examination of exothermic onset temperature and calorific value using High Pressure Differential Scanning Calorimetry (HP-DSC). Additionally, the induction time of the fine powdered coal was investigated using the Spontaneous Ignition Tester (SIT), and the Time to Maximum Rate at adiabatic condition (TMRad) was determined using Accelerating Rate Calorimetry (ARC). Based on the SIT and ARC results, it was observed that if there are hot spots within the fine powdered coal under adiabatic conditions, thermal runaway could occur within a few minutes due to the exothermic oxidation reaction, indicating a high risk of fire during abnormal conditions.

As a new approach to estimating the Self-Ignition Temperature (Tsi), simulations were conducted using ARC data for the oxidation temperature rising rate. The results indicated that the Tsi is estimated to be 314 K at a drum scale of about 200 L, suggesting the potential for spontaneous ignition, particularly during the summer season. We believe that the estimation of Tsi by this method can be applied to other substances prone to spontaneous ignition as well.

In this paper, the incendivity of abnormal discharges occurring from an electrostatic powder coating gun was experimentally examined using two methods (i.e., transferred charge amount measurement test and explosion test). In the whole experiments, the discharge gap (the distance between the nozzle tip and the grounded electrode) was kept constant at 10 mm, and a methane-air mixture gas (12.0%) was used as the test gas in the explosion test. As for the results, under all experimental conditions, abnormal discharge did not occur when the Over Current Limit (OCL), which is the safety device of the electrostatic spray gun, was enabled. When the OCL was released, the absolute value of the transferred charge amount was 70 nC or less when the setting value of the current control device was -80 μA and -110 μA. There were no ignitions under these conditions. On the other hand, when the set value was -120 μA, -130 μA and -140 μA , the absolute value of the transferred charge amount was 1,500 nC or more. There were ignitions because the transferred charge amount greatly exceeded the ignition risk threshold value of 200 nC (absolute value) mentioned in EN50050-2. As described above, since a clear correlation was confirmed between the transferred charge amount measurement test and the explosion test, the ignition risk can be evaluated by grasping the transferred charge amount in advance.

The present study was conducted to survey the effects of the COVID-19 pandemic on medical services provided by mental health institutions to workers in Osaka. A self-administered questionnaire was sent to 615 mental health institutions in Osaka, and 173 responded (response rate: 28.1%). The results revealed that 9.8% of institutions offered telemedicine services. Among the respondents, 53.8% reported an increase in medical treatment services, while 39.9% reported either no increase or a reduction. A total of 68.8% of institutions provided mental health services for patients with COVID-19. Mental health institutions that expanded their medical treatment services offered a range of services, including counselling and rework assistance. Notably, institutions allowing workplace staff to accompany a sick worker during a doctor visit (odds ratio [OR] = 5.77, 95% confidence interval [CI] = 1.57–21.25) and those providing treatment for patients with COVID-19 (OR = 6.56, 95% CI = 1.51–28.43) were more likely to increase medical treatment services. The availability of rework assistance services was positively associated with the availability of telemedicine services (OR = 4.59, 95% CI = 1.33–15.88). Additionally, the presence of psychological staff was associated with the provision of rework assistance services (OR = 2.79, 95% CI = 1.11–11.52). It has been shown that having physicians with qualifications as industrial physicians can lead to the provision of services related to workplace mental health measures, such as consultations on workplace mental health, responding to ‘information provision documents related to workplace reintegration support,’ contracting for the implementation of stress checks, and addressing high-stress individuals after stress checks. These results suggest that physical facilities, financial stability, and human resources were crucial factors enabling mental health institutions to offer diverse medical services during the COVID-19 pandemic.

The research aimed to assess an AI-based cognitive function decline screening tool, “ONSEI^Ⓡ”, in detecting for impaired cognitive abilities due to psychological and physical factors. A total of 153 workers were recruited who performed the ONSEI^Ⓡ assessment, which determined possibility of cognitive impairment in the case of positive reaction, and answered the questionnaires using their smartphones. Participants received daily reminder emails for 60 days, prompting them to perform the ONSEI^Ⓡ assessment and answer a questionnaire containing items pertaining to their everyday life. On the last day, we conducted a survey on the changes in awareness regarding health after participating in this study. Daily surveys showed that subjective mood decline or anxiety was significantly associated with positive results on the ONSEI^Ⓡ. However, subjective physical discomfort on the day of assessment, and sleep disturbance, and excessive alcohol consumption on the previous day were not. The post-study questionnaire revealed changes in the perception of mental health, and efforts toward appropriate sleep and hydration. The ONSEI^Ⓡ lacked sufficient detection sensitivity for impaired cognitive abilities due to psychological and physical factors. However, repetition of the ONSEI^Ⓡ assessment and asking about everyday life might promote awareness of, and behavioral changes in, psychological and physical health.

This study examined the understanding and intentions regarding the disclosure of occupational safety and health conditions among managers of small- and medium-sized enterprises (SMEs) recognized as excellent in health management. Results showed that while managers quantified information on occupational accidents, they did not grasp information related to turnover intention and perceived organizational support. Additionally, while intentions to understand employee stress and work engagement were high, intentions to understand employees’ exercise habits were low. This indicates that although managers consider the mental health and work motivation of employees important, they may not emphasize information leading to lifestyle improvements. Reasons for insufficient grasp or low intentions include lack of mandatory requirements, expertise in occupational safety and health, and privacy concerns. Regarding disclosure, there was a high intention to disclose information on occupational accidents and frequency rates, indicating recognition of the importance of proactively disclosing such information to enhance transparency. It is necessary for managers to evaluate the importance and impact of items when deciding whether to disclose them. Therefore, managers should seek advice from occupational health staff or external experts on evaluation and improvement methods for indicators.

The safety and health of persons with disabilities at work must be tailored to their individual disabilities. To study occupational accidents and evaluate their characteristics and work methods/environments, we conducted interviews about accidents and safety/health management, including disability considerations, and observed work methods/environments in six private-sector establishments where people with disabilities work and four workplaces that provide welfare services.

There were no disability-related work accidents. Consideration was given to creating a quiet environment to ensure the peace of mind for workers with intellectual, developmental and mental disabilities. Medication management and seizure response for individuals with epilepsy or psychiatric disorders and the medical characteristics of the developmentally and mentally disabled were not well understood by the managers. The physical environment for the physically disabled was appropriate for their physical functions. There were many accidents due to falls and collisions in the welfare-to-work center, and the workload reduction measures usually taken in general companies were insufficient. For the safety and health of persons with disabilities at work, a consultation and guidance system of experts and intervention mechanisms was necessary, with a comprehensive perspective of medical care and occupational health, welfare for the disabled in the work system, and management of small enterprises.