In 2015, several bladder cancer cases were reported in chemical plants in Japan, and aromatic amines including ortho-toluidine (OT) were suspected as the causative agents. The air concentration of OT was far below the occupational exposure limits recommended by Japan Society for Occupational Health but the concentration of this substance in workers’ urine was high, suggesting that the workers might have received dermal exposure to aromatic amines. In order to understand the actual exposure of aromatic amines, it is necessary to use the exposure assessment by biological monitoring. The NIOSH method 8317, a quantitative analysis of OT in urine, is the representative method for the biological monitoring of OT exposure. However, the method has some weak points; it has not been verified whether the method could analyze the urine from workers co-exposed to several kinds of aromatic amines, and the effect of urine constituents (matrix effect) on the analysis.
In this study, we developed a new analytic method in biological motoring for aromatic amines with offset matrix effect using liquid chromatography-tandem mass spectrometry. We examined whether we could analyze six kinds of aromatic amines used in the factories with the occurrence of bladder cancer, including OT, aniline (ANL), 2,4-dimethylaniline (DMA), ortho-anisidine (ANS), ortho-chloroaniline (OCA), para-toluidine (PT) and their metabolites using our new method. The sensitivity of this method is good for the five aromatic amines except OCA, and OT, ANL, DMA and ANS were detected in the urine samples of workers. In conclusions, we developed a new quantitative analysis method of urine samples which is useful for the biological monitoring of co-exposure to several kinds of aromatic amines.
The usage of powered exoskeletons has been reported to benefit gait reconstruction in patients with spinal cord injury (SCI). However, few studies have reported on the aspects of safety. We investigated and observed rehabilitation using exoskeleton, and performed a risk analysis for safer exoskeletons. First, we reviewed reports on adverse events and found a high incidence of skin troubles and device malfunctions but a low incidence of falls. It suggests the usefulness of support from human helpers. Second, gait training using two types of exoskeletons was performed at a rehabilitation center. The falling of a paraplegic patient with an exoskeleton was prevented by the contact assistance and supervision of two physical therapists, thus confirming that safety was dependent on human support. On the other hand, the specific themes of rehabilitation using exoskeletons were also found, such as unstable walking, behaviors suggesting psychological and physical fatigue in physical therapists, and problems of fitting and usability. Finally, the risk assessment results indicated the engineering protective measures to multiple hazards reduced the risk score, but some unavoidable risks, such as falls, remained without the human supports. The development of safer exoskeletons requires comprehensive risk reduction measures through engineering protection and human support which assumed the usage of patients with SCI and their helpers.
This study aimed to examine the actual situation and background factors associated with overwork-related disorders, such as cerebrovascular/cardiovascular disease (CCVD) and mental disorders, among teachers/workers in education/school services. Eighty-two eligible cases involving compensation for CCVD and mental disorders of the teachers/workers in education/school services were included in the study from a database containing all relevant cases reported between January 2010 and March 2015 in Japan. “Long working hours” was a principal characteristic of CCVD. The cases of mental disorder were associated with “Long working hours” and “Interpersonal conflict”. Among teachers, the number of compensated cases by job type was highest among “University teachers” and “High school teachers” for both the CCVD and mental disorders. With respect to job-specific burdens, more cases were attributed to “committee/meeting” and “business trip” in “University teachers”, “club activity advisors”, and “classroom teachers” in “High school teachers”. These findings suggest that reducing job-specific burdens is needed, in addition to overtime legislation to prevent overwork-related CCVD and mental disorders of the teachers/workers in education/school services.
The aim of this research was to identify and analyze examples of occupational accident reduction in retailing, restaurant, and social welfare facilities by surveying companies where the number of occupational accidents has decreased or remained unchanged. According to the results of the survey, overall activities initiated by headquarters appeared to be a key factor in reducing occupational accidents at the facilities. It is especially important that facility managers participate in Health and Safety committee and executive committee meetings, and that the decisions made in these meetings are carried out promptly and actively.
It was also found that, in the case of retailing, proactive efforts were being made to forecast the potential risks associated with day-to-day operations, with the aim of eliminating sources of hazards, including the use of non-slip shoes and floor materials, applying snow-melting agents in parking lots, providing cut-resistant gloves, and eliminating the use of step ladders. At restaurant facilities, where there is a chronic shortage of workers, the optimization of business operations resulting in a reduction in man-hour requirements has contributed to a reduction of risks and an improvement in occupational safety.
In the case of social welfare facilities, while equipment such as robots, sliding boards and sliding sheets has been introduced to prevent occupational lower back pain among care workers, countermeasures designed to prevent falls have not been taken. On the other hand, welfare facilities serving disabled persons have actively implemented hazard protection training and safety education on a regular basis.
In general, the survey revealed that the current level of awareness and commitment to promoting a safety culture and providing safety education is less than satisfactory, and that a continued effort in this regard is needed.
Although occupational injuries in the manufacturing industry have decreased overall, the occurrence of fall-related injuries has remained unchanged. This may be due to a higher number of older workers, and an increased ratio of older workers to total employees. Therefore, it is necessary to develop workflow guidelines to prevent fallrelated accidents involving older employees. Based on the results of our literature review, we developed some key questions (KQ) for older factory workers. Furthermore, we described a draft guideline for each KQ. In our proposal, we combined (1) conventional strategies for mitigating environmental harm, and (2) individual exercise interventions to improve the workers’ fitness. We believe that these tentative recommendations will further aid fall-prevention initiatives. In the future, to investigate the effectiveness of our guidelines, we hope to conduct external surveys of occupational health staff within several manufacturing establishments. These will be followed by an expert panel discussion to formally complete them. Our current guidelines will be helpful for industry workers, and employers who wish to reduce injuries and liabilities in the workplace.
The electromagnetic susceptibility (EMS) is the sensitivity of a device to an incoming electromagnetic interference. It is especially very important for devices related to safety to operate normally under unexpected noise. This paper experimentally investigated the EMS of ten kinds of commercial earth leakage circuit breakers (Equipment under test: EUT). This EMS test was carried out in a 3-meter anechoic chamber with an EMS automation measuring equipment, vertical radiating (or horizontal) antenna, and electric filed probe, and etc. During the test, the EUT was monitored through a video camera to check whether any malfunctions occurred. As for the results, there were no malfunctions for the electric field strength and frequencies mentioned in the JIS standard. However, some of the EUT malfunctioned at several specific values not mentioned in the JIS standard. In addition, a countermeasure to prevent malfunction is also mentioned in this paper.
Electrostatic discharge (ESD) is one of the electromagnetic wave noise sources which affect the function of mechatronics equipment. Spark lengths, discharge currents and electric fields at the occurrence of ESD were measured when a charged object approached a grounded object. It was confirmed that the spark lengths tended to shorten when approach speeds of the charged object increased. It was also confirmed that peak discharge currents tended to increase and rise times of the discharge current tended to shorten when the spark lengths shortened. Time change rates of electric field tended to become faster and amplitude spectra of the electric field tended to increase when the spark lengths shortened. Maximum values of time change rate of the electric field at 138 mm away from the point where ESD occured correlated with the peak discharge current, maximum values of the time change rate of the discharge current, and maximum second order differential values of the discharge current; quasi electric field was dominant among components of the electric field measured in this experiment.
Various storage tanks are employed in wind turbine, solar cell, and bio-mass energy systems to regulate fluctuation caused by weather or process transits. However, this accumulated energy might be released uncontrollably causing fire and explosions. The roof section of a storage tank is separated from the side wall by a preset pressure increase to minimize the explosion effect. In some cases, the separated roof moves beyond the planned limit; thus, damaging the missile. In an oil tank safety study, it was found that a small diameter tank generates a higher pressure increase than a large diameter tank, and that this pressure induces the lift of the bottom section. In this study, a simple model is proposed to estimate the flight velocity, angle, duration, and energy of the roof section of a storage tank.