Health and Safety Education for Painting Workers in Small Companies to Make Them Aware That Paint Is "Dangerous and Harmful".

Workers in painting companies may be unaware that the paints they handle have adverse health effects. The present study explored the factors associated with workers' perception of paints as "dangerous and harmful". A questionnaire survey and interviews were conducted with workers engaged in painting operations in small-sized painting companies (fewer than 50 employees) in northern Kyushu and Yamaguchi prefectures. Safety and health education methods making workers perceive paint as "dangerous and harmful" were clarified. Fisher's exact test and logistic regression analysis were used for the survey and hierarchical cluster analysis for the interviews. The factor "Hazard prediction activity (KY Activity)", gender, and job position were identified as factors that make workers perceive paint as "dangerous and harmful". Based on the interview results, "KY Activity" was a keyword and a standardized safety and health activity. Before work, workers gather in a small group to discuss the dangers and hazards of paint, share information, establish action goals, and confirm safety measures. The questionnaire identified "KY Activity" as a factor influencing the workers' perception of paint as "dangerous and harmful". "KY Activity," also extracted from the interviews, is an effective health and safety education method for teaching workers in small-sized painting companies that paint is "dangerous and harmful".

[Support Needed for the Transition From Legal System Management to Self-Controlled Management of Chemical Substances].

An open-ended questionnaire was administered to the participants of a six-part lecture series on self-controlled management of chemical substances regarding the support those participants would need when transitioning to that system, and the required elements of support were examined using a text-mining tool (KH Coder Ver. 3). The subjects were 59 persons who attended the lectures on an overview of self-controlled management of chemical substances and answered a questionnaire after the course. The lectures were organized by the Graduate School of Occupational Health, University of Occupational and Environmental Health from January-February 2022. The participants themselves indicated that they needed knowledge and up-to-date information on the revised law, as well as education about chemical substances. As for the support needed for individuals, the following were considered necessary: to provide support for education; management; information; the latest information; and education about the toxicity and dangers of chemical substances, which are necessary for education and chemical substance management in accordance with the revised law. As for the support needed for organizations, it was considered necessary to support the understanding of top management and the securing of necessary human resources.

[Causes of Countermeasures Against Serious Accidents Caused by Health Hazards of Chemical Substances, Based on Cases of Occupational Accidents in Japan].

The purpose of this study was to summarize the typical and specific causes and risk reduction measures of serious accidents in Japan caused by chemical substances in terms of the 10 types of human health hazards in the UN GHS (Globally Harmonized System of Classification and Labelling of Chemicals) classification. The list of "Cases of Major Accidents Caused by Chemical Substances" published on the "Safety in the Workplace Website" of the Ministry of Health, Labor and Welfare (MHLW) was linked to the "Results of GHS Classification by the Government" of the National Institute of Technology and Evaluation (NITE). Analysis was conducted by health hazards in order to obtain reference examples of measures taken against health hazards in response to the revision of the law on autonomous chemical substance management in 2022. Using the text mining tool KH Coder ver. Three using cluster analysis, we grouped causes and measures among serious disasters by health hazard, illustrated co-occurrence networks, and extracted typical examples of each in a co-occurrence network. Representative causes of and measures against occupational accidents caused by health hazardous properties were summarized from the extracted typical cases. Although few occupational accidents were caused by the health hazards of chemicals, when all health hazards were classified into acute toxicity, acute health hazard, and chronic health hazard, contact was a clear cause for many of the acute toxicity and acute health hazards, such as corrosiveness and sensitization. However, many occupational accidents were caused by the physical hazardous aspects of the chemical substances or by the safety aspects of the workplace. Causes of occupational accidents due to health hazards included unsafe behavior and unsafe conditions, or lack of understanding of the physicochemical properties of a substance and specific reactions such as mixing or hydrolysis of the substance. Typical risk reduction measures for health hazards included equipment to prevent human contact with health hazardous substances, systems to control unsafe behavior, promoting understanding of chemical reactions, and providing information about chemicals to all persons involved in testing, research, and subcontract work. The data of occupational accident cases of "death or more than 4 days lost from work" were used. Most of the cases were related to acute health hazards, but relatively few to chronic health hazards, and few occupational accidents were caused by health hazards. Most of the occupational accidents were caused by health hazards due to the physical hazards of chemical substances and inadequate workplace safety. In light of the above, it is necessary in autonomous chemical substance management to first take risk reduction measures for workplace safety and chemical physical hazards, then to prevent contact with acute toxicity and acute health hazards such as corrosiveness and sensitization, and, lastly, to take risk reduction measures for chronic health hazards, using allowable concentrations and controlled concentrations as indices.

[Survey on Preparedness, Concerns, and Support Demands for Autonomous Management of Chemical Substances].

The management of workplace chemicals shifted from a regulatory-based to a self-managed approach as of April 2023. To assess readiness, concerns, and necessary support for this change, a free-response questionnaire survey was conducted for the participants of the "Promoting self-management of chemicals in enterprises" seminar held by the Department of Occupational Health, Graduate School of Medicine, University of Occupational and Environmental Health, Japan, in January-February 2023. Text-mining using KH Coder (Ver.3) was conducted to investigate relationships between words that appeared in sentences using a co-occurrence network and hierarchical cluster analysis. From the questionnaire's description text, combinations of the terms "information" and "collection," "small and medium-sized" and "enterprise," and "chemical" and "substance" were extracted. Results suggest a need for "information gathering" and "support for small and medium-sized enterprises."

Capability of Relative Odor Level Monitors to Measure the Odor of Thirdhand Smoke.

We investigated the probability of measuring the odor of thirdhand smoke using four odor-measuring monitors and three gas detector tubes. We measured the changes in tobacco odor on paper towels and cloth products over time. The results of the measurements were plotted against time to obtain an exponential approximation curve. The coefficient of x and the R2 values were calculated from this curve. The odor indicated by four types of odor-measuring monitors and three types of gas detector tubes decreased exponentially over time. The curves obtained from all measuring devices had coefficients of ex between -0.001 and -0.021, and R2 values of >0.8. The reproducibility of measuring relative odor levels through all measuring devices was high, suggesting a good capability of measuring thirdhand smoke odor. Two different odor-level standard gases can be used for the calibration of the regression curve for each monitor.

Characteristics of Adsorption of Organic Solvent Vapors by a New Porous Carbon Material Made of Rice Husk as Measured by Breakthrough Curves.

We investigated the adsorbed amount of organic solvent vapors and adsorption rate of a new porous carbon material made from rice husk (rice husk activated carbon) in comparison with those of coconut shell activated carbon by the breakthrough curve. The adsorbed amount on the rice husk activated carbon and that on the coconut shell activated carbon were 81.3 ±â€¯3.3 mg/g and 71.7 ±â€¯5.0 mg/g for acetone, 8.0 ±â€¯1.7 mg/g and 6.3 ±â€¯0.2 mg/g for methanol, 196.8 ±â€¯8.8 mg/g and 262.8 ±â€¯10.4 mg/g for ethyl acetate, 234.8 ±â€¯11.9 mg/g, and 364.6 ±â€¯43.8 mg/g for toluene, respectively. These results suggest that the amount of organic solvent vapors adsorbed per unit weight of rice husk activated carbon is slightly larger for high polar compounds and is smaller for low polar compounds than that of coconut shell activated carbon. We compared the adsorption rate of the two materials by using the slope of the breakthrough curves. Even though there are some limitations to the characteristics of the new porous carbon material, it may be possible to use rice husk activated carbon as an alternative to coconut shell activated carbon in occupational and environmental measures.

[Characteristics that Occupational Safety and Health Engineers Should Know Before Conducting Health and Safety Education for Workers with Developmental Disorders].

As a result of the amendment to the act on promotion of employment of persons with disabilities the statutory employment rate for handicapped people was raised from 2.0% to 2.2% in April 2018. By 2021, it will be raised again by 0.1% to 2.3%. The number of jobs for handicapped people has also been increasing recently, and it is predicted that the number of jobs for people with developmental disorders will also increase. From this perspective, it is predicted that occupational safety and health engineers, such as health officers, will have more opportunities to give safety and health education to workers with developmental disorders. People with developmental disorders have various characteristics that are different from those with an ordinary type of development, and occupational health and safety engineers need to understand their characteristics when providing education for them. This report summarizes the characteristics of people with developmental disorders that occupational safety and health engineers should know when educating them.

[Adsorption Characteristics of Volatile Organic Compounds on Used Coffee Grounds Based on the Breakthrough Curves].

We investigated the adsorption characteristics of volatile organic compounds (VOCs) on the surface of coffee beans after extraction (coffee grounds). Temperature-controllable adsorption equipment of VOC vapor was manufactured, and nitrogen gas containing about 100 ppm of VOC vapor was introduced into a coffee extraction residue. The air in the downstream was analyzed with a gas chromatograph equipped with a flame ionization detector over a period of time. A breakthrough curve was obtained from the analysis of values and time, and the adsorbed amount of each volatile organic compound on the coffee grounds was calculated from a graphical integration of the breakthrough curve. Fourteen VOCs were tested, and the adsorbed amount tended to increase with increases in the boiling point of the VOCs. It was also found that the adsorbed amount of methanol and toluene was affected by the water content in the coffee grounds used in the experiment.

Examination of a New Desorption Method for Solid Adsorption Method of Working Environment Measurement －Attempt to Improve Desorption Efficiency of Organic Solvents from a Coconut-Shell-Activated Carbon Using Surfactant Solutions－.

For a new desorption method development for working environment measurement, desorption efficiency of organic solvent vapors from an activated carbon was examined using desorption solutions that consisted of anionic and nonionic surfactants. Ten µl of an aqueous solution of isopropyl alcohol or methyl ethyl ketone diluted with distilled water was spiked into a 10 ml vial with a coconut-shell-activated carbon (100 mg). The vial was left for 24 h, and 5 ml a desorption solution was added. Afterwards, the vial was put into an incubator at 60°C and left for 24 h, then the desorption efficiency was determined by analyzing the headspace gas in the vial with a gas chromatograph equipped with flame ionization detector. By adding one or four kinds of nonionic surfactants to the aqueous solution containing two kinds of anionic surfactants, the effect adding nonionic surfactant to the desorption efficiency was investigated, but improvement of desorption efficiency was not observed. On the other hand, desorption efficiency varied depending on the production lot of the coconut-shell-activated carbon tube used as the adsorbent.

Decomposition Characteristics of Toluene Vapor Using Titanium Dioxide Photocatalyst and Zeolite Thermally Sprayed on an Aluminum Fiber Filter.

Decomposition characteristics of toluene vapor by titanium dioxide photocatalyst and zeolite that are prepared by thermal spraying on an aluminum fiber filter (photocatalyst filter) were investigated. Toluene vapor was injected into a small chamber made of stainless steel, and an air cleaner equipped with the photocatalyst filter was operated. The vapor concentration in the chamber decreased exponentially. The decreasing rate of toluene vapor in the chamber depended on the initial toluene concentration, and the higher the initial vapor concentration was, the lower the decreasing rate was obtained. The decreasing rate was constant during each decomposition experiment, although the concentration decreased with time. To investigate the effect of zeolite on the reduction of the vapor concentration, we compared the decreasing rates of toluene vapor by photocatalyst filters with and without zeolite.The decreasing rate of toluene concentration using the filter without zeolite was larger than that with zeolite. The reason for this would be that photocatalyst decomposed toluene not only in air but also adsorbed in zeolite.

[Trial of a rapid measurement method by absorption photometer for the determination of the number of bacteria in the air].

A quick method to measure the number and the concentration of airborne bacteria was examined by combining bacteria staining with a crystal violet solution and absorptiometry. The suspension of the bacteria isolated from the environment was adjusted to 3.0 × 10(8) colony forming units (CFU) / ml in E. coli equivalent, and a 10-fold dilution series was created. After centrifugation of each bacterial suspension, the supernatant was removed and the bacteria were stained by adding a crystal violet solution. The sample was centrifuged again, and the supernatant was collected and named the unabsorbed sample. The residual bacteria were washed two times, and ethanol was added to the stained cells. The recovered solution collected by centrifugation of the cells was named the recovered sample.The chemicals in the samples were examined by high performance liquid chromatography, but no peak could be observed without the staining material. Absorption spectrophotometry showed that the determination limit of bacteria in the unabsorbed samples was 3.0 × 10(7) CFU / ml in E. coli equivalent and that in the recovered samples was 3.0 × 10(8) CFU / ml, indicating that the unabsorbed sample had a lower determination limit.

Characteristics of a real time monitor using the interference enhanced reflection method for organic vapors.

Performance and sensor characteristics of a monitor for volatile organic compounds (VOC monitor) using the interference enhanced reflection (IER) method were investigated for 52 organic solvent vapors that are designated as class 1 and class 2 organic solvents by the Ordinance of Organic Solvent Poisoning Prevention in Japan. Test vapors were prepared by injecting 1 to 3 µl of liquid solvent into a 20 l Tedlar(®) bag and perfectly vaporizing them. The vapor concentration was simultaneously measured with the monitor and a gas chromatograph (GC) equipped with flame ionization detector, and both values were compared. The monitor could detect all the solvent vapors that we used. Linear response was obtained between the concentration measured by the monitor and those by the GC. The monitor could detect 1/10 of the administrative control level for 37 of 52 solvent vapors, including toluene and xylenes. For 15 vapors, on the other hand, the monitor could not be used for the working environment measurement because the sensor response was low or the regression lines did not pass through the origin.

Identifying factors that inhibit or facilitate on-site implementation of chemical risk assessment at small and medium-sized companies.

The introduction and implementation of chemical risk assessment is difficult, especially at small and medium-sized manufacturing and construction companies. This study aimed to identify the factors that inhibit or facilitate such assessment. Twelve individuals in charge of risk assessment at one medium-sized client company and eight small and medium-sized contract companies and responsible for innovation in the manufacturing and construction industries were interviewed. The interview transcripts were analyzed via text mining using KH Corder ver. 3 and a co-occurrence network was used to identify the keywords' connections and each factor in consideration of the interviews. Six factors inhibited or facilitated risk assessment: (1) education on hazardous work in the workplace, (2) improvement suggestions and reduction measures from client and staff, (3) cooperation between employees and contractors in the workplace, (4) thoroughly explanation of SDS content for better understanding, (5) risk awareness based on accident examples, and (6) difficulties imagining the hazards of chemical substances. Factors (1), (2), (3), and (5) were positive, facilitating factors; (4) and (6) were negative, inhibiting factors. This study highlights that it is necessary to educate workers about chemical substance risks using safety data sheets and accident examples in chemical risk assessment.

[Sensing characteristics of a real-time monitor using a photoionization detector on organic solvent vapors].

Measurements of organic solvents in the work environment are carried out by either direct sampling using plastic bags/gas chromatography, solid sorbent adsorption using charcoal tubes/gas chromatography, or by a direct reading method using detector tubes. However, these methods cannot always measure the work environment accurately because the concentration of hazardous materials changes from time to time, and from space to space. In this study, the sensor characteristics of a real time monitor using a photoionization detector that can monitor vapor concentration continuously were investigated for 52 organic solvent vapors that are required to be measured in the work environment by the Ordinance of Organic Solvent Poisoning Prevention in Japan. The sensitivity of the monitor was high for the solvents with low ionization potential. However, the sensitivity for the solvents with high ionization potential was low, and the sensor could not detected 7 solvents. Calibration of the sensor using a standard gas was desirable before being used for measurement because the sensitivity of the sensor was variable.

[Changes of the storage stability of ketones collected on activated coconut carbon in environmental ketone measurement].

The storage stability for six ketones was studied on four activated coconut carbons commonly used for air sampling in Japan. As the ratios of the enol form of cyclohexanone and methyl ethyl ketone are high, the ketones showed drastic losses during storage (storage stability), which could be attributed to catalytic oxidation and chemisorption. Moreover, adsorbed water caused a further decrease in recoveries of the ketones from the carbons. Because keto-enol tautomerism and hydration are catalyzed by acid or base, the relationships between the recoveries of the ketones from the carbons and pH in the aqueous solution of the carbons and the ignition residue of the carbons were investigated. As a result, the intensity of acidity or basicity of the carbons correlated with the loss of the ketones during storage, but the ignition residue of the carbons did not. Therefore, these results lead us to the conclusion that a more neutral coconut carbon is more suitable for the collection of aliphatic ketones, and activated coconut carbons are not suitable for cyclohexanone.

Cerebral excitability in pup rats prenatally exposed to 1-bromopropane is suppressed by bromide accumulated in the brain.

Previously, we reported that prenatal exposure to 1-bromopropane (1-BP) causes the accumulation of bromide (Br-) in the brain of rat pups. Here, we aimed to investigate the effects of Br- accumulation in rat pups prenatally exposed to 1-BP vapor. Dam rats were exposed to 1-BP (400 or 700 ppm; 1-BP group) by inhalation, or to NaBr (20 mM; Br- group) in drinking water during gestation days 1-20. We also analyzed pentylenetetrazole (PTZ, 60 mg/kg, ip)-induced behavioral changes in pups prenatally exposed to 1-BP or Br- on postnatal day (PND) 14. PTZ-induced epileptic convulsions were inhibited in both 1-BP (700 ppm) and Br- groups. The inhibition of neuronal excitability induced by Br- was evaluated electrophysiologically using the hippocampal slices obtained from PND14-16 pups. PTZ (2 mM) failed to induce epileptiform discharge in the presence of 1.2 mM Br- in the slices obtained from the control group. However, it induced epileptiform discharge following the removal of Br-, by perfusing artificial cerebrospinal fluid into the slices obtained from the Br- group. Our results indicate that Br- accumulates in the brain of neonatal rat pups prenatally exposed to 1-BP vapor suppressed neuronal excitability.

A new desorption method for removing organic solvents from activated carbon using surfactant.

OBJECTIVES: A new desorption method was investigated, which does not require toxic organic solvents. Efficient desorption of organic solvents from activated carbon was achieved with an ananionic surfactant solution, focusing on its washing and emulsion action. METHODS: Isopropyl alcohol (IPA) and methyl ethyl ketone (MEK) were used as test solvents. Lauryl benzene sulfonic acid sodium salt (LAS) and sodium dodecyl sulfate (SDS) were used as the surfactant. Activated carbon (100 mg) was placed in a vial and a predetermined amount of organic solvent was added. After leaving for about 24 h, a predetermined amount of the surfactant solution was added. After leaving for another 72 h, the vial was heated in an incubator at 60°C for a predetermined time. The organic vapor concentration was then determined with a frame ionization detector (FID)-gas chromatograph and the desorption efficiency was calculated. RESULTS: A high desorption efficiency was obtained with a 10% surfactant solution (LAS 8%, SDS 2%), 5 ml desorption solution, 60°C desorption temperature, and desorption time of over 24 h, and the desorption efficiency was 72% for IPA and 9% for MEK. Under identical conditions, the desorption efficiencies for another five organic solvents were investigated, which were 36%, 3%, 32%, 2%, and 3% for acetone, ethyl acetate, dichloromethane, toluene, and m-xylene, respectively. CONCLUSIONS: A combination of two anionic surfactants exhibited a relatively high desorption efficiency for IPA. For toluene, the desorption efficiency was low due to poor detergency and emulsification power.

Comparison of sensor characteristics of three real-time monitors for organic vapors.

OBJECTIVE: Sensor characteristics and performance of three real-time monitors for volatile organic compounds (VOC monitor) equipped with a photo ionization detector (PID), a sensor using the interference enhanced reflection (IER) method and a semiconductor gas sensor were investigated for 52 organic solvent vapors designated as class 1 and class 2 of organic solvents by the Ordinance of Organic Solvent Poisoning Prevention in Japan. METHODS: Test vapors were prepared by injecting each liquid solvent into a 50 l Tedlar® bag and perfectly vaporizing it. The vapor concentration was from one-tenth to twice the administrative control level for all solvents. The vapor concentration was measured with the monitors and a gas chromatograph equipped with a flame ionization detector simultaneously, and the values were compared. RESULTS: The monitor with the PID sensor could measure many organic vapors, but it could not detect some vapors with high ionization potential. The IER sensor could also detect many vapors, but a linear response was not obtained for some vapors. A semiconductor sensor could detect methanol that could not be detected by PID and IER sensors. CONCLUSIONS: Working environment measurement of organic vapors by real-time monitors may be possible, but sensor characteristics and their limitations should be known.

An effective method for extracting DNA from contaminated soil due to industrial waste.

Recently, labor accidents caused by toxic gas production such as H2S and CH4 have happened at some waste disposal sites and illegal dumping sites in Japan. The gas production has been known to be end products of bacterial respiration. In order to investigate a microbial flora in industrial waste contaminated soil by a DNA-based detection method, we developed a simple DNA extraction method. The method is based on lysis with sodium dodecyl sulfate (SDS) and a high concentration (4.0 mg/ml) of lysozyme at room temperature. DNA yields increased according to the concentration of lysozyme (0-2 mg/ml), although the cell lysis occurred at comparable efficiency independent of the lysozyme concentration. Interestingly, bovine serum albumin and insulin (4 mg/ml) also contributed high DNA yields. This suggests proteins play an important role at high concentration on a DNA extraction process, presumably by suppressing DNA degradation or adsorption. DNA yields from three contaminated soil samples at 0.3, 1.5 and 3 m in depth by using our method were significantly higher than those extracted by using a widely-used conventional method which did not contain lysozyme. A novel and simple DNA extraction method using high concentration of protein was established for a DNA-based detection method of microbial flora in soil.