The machinery safety standards originating from Machinery Directive 98/37/EC, which matched and harmonized European standards on machinery in January 1995, have been recognised at the international level. Having been considered as global standards that would remove impediments to the free circulation of machinery, Member States of the World Trade Organization (WTO) and signatories to the agreement on Technical Barriers to Trade (TBT Agreement) adopted them as national standards, and they have become increasingly established on a global basis. International standards for machinery safety observe the hierarchical structure stipulated in ISO/IEC Guide 51, which classifies machinery and electrical technologies respectively in ISO and IEC standards. Whereas most modern machinery is powered by an electric drive, safety monitoring of the entire machine and hazard avoidance during abnormality can only be carried out by electronic controls, with the exception of the prevention of electric shock or electrical fires as electrical safety. It is obvious that machinery safety cannot be attainable without electrical safety technology. With a clear understanding of the current situation of machinery safety in Japan, this thesis will first look at the benefit of introducing international safety standards into manufacturing industries in Japan and risk assessment techniques as a means to achieve mechanical safety. It will then propose standardization based on the compliance with international electrical standards as one method to achieve the safer machinery the manufacturing industry has sought for, and examine its effectiveness with practical examples.

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Most labor accidents during open cut excavation work are caused by slope failure, and the importance of countermeasures has long been recognized. Standards for the gradient of excavation surfaces were established in 1965 following an amendment by the Ordinance on Industrial Safety and Health, Japan. This paper introduces the regulations and design standards for the gradient of excavation surfaces for each institution. The historical background of enactment is investigated and some numerical analyses are carried out regarding the standard for the gradient of excavation surfaces, which is covered by Articles 356 and 357.

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Objective: Although numerous corporations have mental health management, there is no clear association between those mental health management and the work outcomes of sick-listed employees. The present study investigated the association between implementation of corporate management and work outcomes.
Methods: A questionnaire was sent to 10,000 randomly selected corporations, and 1,361 (13.6%) responses were received. After excluding invalid responses, 171 of these were subjected to analysis. The number of full-time workers, implementation of corporate management, and the number of incidences of each work outcome (sickness absence, employee attrition, relapse, and return to work) were collected and analyzed using logistic regression.
Results: There were six to 12 significant positive associations observed between corporate management and each work outcome, and three to five of these remained after adjusting for company size.
Discussion: Relatively higher proportions of sickness absence, employee attrition, and relapse were observed in corporations which implemented mental health management. This does not necessarily mean, however, that implementation of mental health management leads to the occurrence of mental health problems. Rather, it is appropriate to interpret these associations as reflecting the reality that employees in each work outcome category tend to be identified more readily in corporations which implement mental health management.

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Many studies have measured the salivary cortisol level as a method for assessing psychosocial stress. In this paper, we introduce 3 measures of cortisol (daily output, slope, and awakening response) that were estimated by multiple saliva samplings in daily settings. These measures reflect different patterns of diurnal cortisol secretion and have different associations with exposure to acute, chronic, and severe stressors. Considering the characteristics of each cortisol measure and the availability of these protocols at the workplace, measurements of salivary cortisol should be utilized effectively for the assessment of stress.

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Workers handling and painting with powdery paint have a risk of unintentional exposure to nano-particles during their work. Nano-particles in powdery paint were observed by transmission electron microscopy (TEM) directly without any pretreatment, or with the following pretreatment. An ultra-thin section of epoxy-resin embedded original powdery paint was made using ultra-microtome after a pre-coat of gold was applied to the powdery paint by gold vapor deposition treatment. Nano-particles were observed located not only inside the powder also on the surface. Our results show that the preparation method applied in this research works effectively for TEM observations.

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To monitor the exposure to airborne toxic substances in a small-scale workplace, such as a chemical laboratory, a real-time monitor and a passive gas sampler can be used. The apparatus is set up at the center and other points of the room so that the exposure in the room can be evaluated. Thus, we can determine whether the concentration of the above-mentioned toxic substances is high or low and determine whether or not the workplace is safe. However, when a VOC (Volatile Organic Compound) monitor is used for real-time monitoring, concentration of various toxic substances in a vapor-phase mixture are measured with the help of a passive gas sampler, and appropriate corrections are made to the obtained values. When the measurements are carried out by using a working environment measurement system, the 2nd evaluation value etc. are taken into consideration, and when the measurements are performed by using a real-time monitor, the results of the mean value are taken into consideration. The exposure evaluation can be carried out using the estimated concentrations of the toxic substances. This evaluation will be useful in the autonomous risk assessment.

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In Japan, natural disasters such as typhoons or earthquakes occur every year. This means that disaster relief works need to be carried out every year. There are certain specific risks that apply to relief works, such as the sudden collapse of existing building structures or the urgency of restoration tasks. It is therefore important to prepare all necessary safety measures beforehand. However, there has so far been little analysis of the work accidents that have occurred at past disaster relief works. This study addresses this with a quantitative investigation of construction work accidents that have occurred during past disaster relief works. It was found that falling accidents were the most prevalent type of accident in construction and civil works, and about 90% of fatal accidents at construction works were fall accidents.

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[in Japanese]

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