• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.8 no.1
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• pp.67-75
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• 1998

The objectives of this study were both to evaluate the level and correlations of hazardous agents and to suggest measures to control industrial hygiene problems caused by using water-soluble metalworking f1uids(MWF). Geometric mean of formaldehyde(0.039 ppm) was higher than criteria of NIOSH(0.016ppm). Formaldehyde, originally existed in the biocide, is released and used to kill microbes in soluble MWF. Microbe concentrations were above $10^4No./mL$ in 14 MWF tanks among 20 tanks surveyed. Nitrosamines that is formed by reaction of nitrosating group and amines was detected to $18.4-47.1{\mu}g/m^3$. Formaldehyde concentration was low when microbes were abundant(r=-0.67, p=0.011), and high when open tank area was wide(r=0.75. p=0.012). The significant relationship between pH and microbes(r=-0.76. p=0.003) was also observed. The predominant bacteria species in MWF were Pseudomonas spp., Bacillus spp., Comamonas testosteroni, Acinetobacter haemolyticus, Bordertella bronchiseptica in order. Therefore, hazardous agents emitted by using water-soluble MWF seems to be correlated microbial growth. In order to minimize worker's exposure to several hazardous agents by an water-soluble MWF and to increase productivity, microbial growth must be controlled to the lowest level as possible. Administrative control as well as engineering control must comprehensively be applied to control microbe's growth in water-soluble MWF.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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• pp.326-329
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• 2005

A worker who grinded the inner parts of camshafts for automobile engines using water-soluble metalworking fluid (MWF) for 14 years was diagnosed with sinusitis. We postulated that the outbreak of sinusitis could be associated with exposure to microbes contaminated in water-soluble MWF during the grinding operation. To suggest responsible agents for this outbreak, quantitative exposure assessment for chemical and biological agents and prevalence of work-related respiratory symptoms by questionnaire were studied. The exposure ranges of MWF mist (0.59 $mg/m^3$to 2.12 $mg/m^3$) measured during grinding exceeded 0.5 $mg/m^3$ of the recommended exposure limit (REL). Grinder's exposures to bacteria, fungi and endotoxins were also generally higher than not only the proposed standards, but also those reported by several studies to identify the cause of respiratory effects. Statistical test indicated that the prevalence rate of reported symptoms related to nasal cavities showed no significant differences among the operations. Evaluation on grinding operation characteristics and quantitative exposure assessment indicated that repeated exposure to MWF mist including microbes contaminated from the use of water-soluble MWF may cause respiratory diseases like sinusitis or at least increase susceptibility to the development of sinusitis

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.1
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• pp.1-12
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• 2007

We have reviewed all cases and epidemiological studies that have reported the association between worker's exposure to metalworking fluids(MWF) and non-malignant respiratory diseases. The followings are main conclusions we critically reviewed. Exposure to MWF was believed to be significantly related to the risk of cough and phlegm. Relative risk caused by straight MWF was found to be higher in exposure to straight MWF than water-soluble MWF. We also found that exposure to water-soluble MWF significantly caused hypersensitivity pneumonitis (HP) and occupational asthma. The main culprits that cause the development of HP and asthma are believed to be microbes contaminated in MWF, ethanolamine and biocides. HP and asthma could be developed at even exposure to lower than $0.5mg/m^3$, exposure level recommended by NIOSH. Most epidemiological studies have reported that relationship between chronic bronchitis and exposure to MWF was significant. Although there were several studies that suggested the significant association between exposure to MWF and the development of rhinitis and sinusitis, we could not conclude the causal relationship because of lack of evidences.

• Safety and Health at Work
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• v.3 no.1
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• pp.1-10
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• 2012

The aim of this review was to assess current knowledge related to the occupational exposure limit (OEL) for fluid aerosols including either mineral or chemical oil that are generated in metalworking operations, and to discuss whether their OEL can be appropriately used to prevent several health risks that may vary among metalworking fluid (MWF) types. The OEL (time-weighted average; 5 mg/$m^3$, short-term exposure limit ; 15 mg/$m^3$) has been applied to MWF aerosols without consideration of different fluid aerosol-size fractions. The OEL, is also based on the assumption that there are no significant differences in risk among fluid types, which may be contentious. Particularly, the health risks from exposure to water-soluble fluids may not have been sufficiently considered. Although adoption of The National Institute for Occupational Safety and Health's recommended exposure limit for MWF aerosol (0.5 mg/$m^3$ ) would be an effective step towards minimizing and evaluating the upper respiratory irritation that may be caused by neat or diluted MWF, this would fail to address the hazards (e.g., asthma and hypersensitivity pneumonitis) caused by microbial contaminants generated only by the use of water-soluble fluids. The absence of an OEL for the water-soluble fluids used in approximately 80-90 % of all applicants may result in limitations of the protection from health risks caused by exposure to those fluids.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.2
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• pp.131-138
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• 2010

This technical report was developed to suggest the guideline to assess the safe use and handling metalworking fluids (MWFs) in machining operation. The basis of this method developed in this study was based on self assessment procedure recommended by Organization Resources Counselors (ORC) of the United States (US). In addition, various MWF management elements obtained from the review on various articles, reports and author's experience regarding MWF were newly added to the evaluation guideline. A total of four areas were finally selected in order to control exposure to MWF used in machining operations. They are all related to the presence and efficiency of the control measures, exposure assessment, management on tank and sump, and safe treatment of chips and metal fines generated during machining operations. Each area is consisted of several related elements. Several evaluation areas and elements used in this study could be revised, replaced, added and deleted according to the process environment, evaluation objectives and evaluator's (manager) criteria etc. This evaluation guide manual could be used for safe management of MWF in metalworking operation. In addition, industrial hygienists can use this evaluation method for auditing and evaluating the management status on MWF.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.1
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• pp.52-60
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• 2005

This study was carried to assess the accuracy of material safety data sheets (MSDS) for some water-soluble metalworking fluid (MWF) with respect to mono- ethanolamine(MEA), di-ethanolamine(DEA) and tri-ethanolamine (TEA). 39 fresh and 52 used MWFs for this study were taken from the workplace. The quantification and qualification of MEA, DEA and TEA were done using ion-chromatography. Three main findings of this study were 1) EA that was not addressed in material safety & data sheets (MSDS) was found to be enough higher than 1%, 2) 33.3% of 39 fresh MWF showed ingredient and concentration of MEA, DEA and TEA in MSDS and 3) the concentrations of MEA(20.5%), DEA(41.3%) and TEA(15.4%) were much higher than those indicated in MSDS. Consequently, we concluded that the accuracy on ingredients and concentrations of MEA, DEA and TEA provided in MWF was very low. Our study recommends that the limit concentration of chemical except for carcinogen that employer has to indicate in MSDS should be lowered from 1% to 0.1% .

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.3
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• pp.169-176
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• 2013

Objectives: The aim of this study is to critically review the health effects of not only direct exposure to biocide, but also indirect exposure to by-product hazardous agents generated through the use of biocide in metalworking operations. Methods: An extensive literature review was conducted of studies reporting on respiratory disease cases, particularly hypersensitivity pneumonitis (HP), in environments using water-soluble metalworking fluids (MWFs). Keyword search terms included 'metalworking fluids', 'machining fluids', 'metalworking operation' 'machining operation' and 'biocide', which were also used in combination. Additional articles were identified in references cited in the articles reviewed. Results: Several of the field, epidemiological and experimental studies reviewed assumed that the symptoms and signs typical of HP developed in machinists who handled water-soluble MWF could be caused by inhalation exposure to nontuberculous mycobacteria (NTM). Most NTM are known to be not only resistant to both biocide and disinfectant, but also to have acid-fast cell walls that are highly antigenic. The presence or persistence of the Mycobacterium species, referred to as NTM, in metalworking fluid-using operations may be caused by NTM contamination in either the natural water or tap water that is used to dilute the base oil and additives for water-soluble MWFs. This hypothesis that NTM contamination in water-soluble MWFs is a causative agent of HP has high biologic plausibility, such as antigenic property, hydrophobicity and small diameter (< 5 um). Conclusions: Aerosolized mycobacteria colonized from MWF are likely to be causing the HP. Inhalation exposure to mycobacteria should be considered as a possible cause for the development of HP.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.4
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• pp.284-292
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• 2012

Objectives: The objective of this study was to investigate the relations between the bacterial concentration and the environmental factors in the water soluble metal working fluids at factories. Methods: The bacterial concentrations for airborne and fluid samples of 7 factories were quantified during the summer season. And we statistically analysed the relations between the bacterial concentrations and the factors such as temperature, relative humidity, usage quantity, mixing ratio and exchange interval. Results: The geometric mean levels of the airborne bacterial concentrations were 79.1(range : N.D.~686) $CFU/m^{3}$ and 68.1(range: N.D.~919) $CFU/m^{3}$ in the process and outdoor. The airborne bacterial concentrations showed no statistical difference by process, usage quantity, mixing ratio and exchange interval. The airborne bacterial concentrations had negatively weak correlations with air temperature and relative air humidity(p<0.05). The bacterial concentrations and pH showed significantly negative correlations in the fluids(p<0.05). And the airborne bacterial concentrations in factories and those in metal working fluids showed no statistical relationship. Conclusions: In the water soluble metal working fluids using factories, the airborne bacterial concentrations of the process were related to those of the outdoor and environmental factors, rather than the onsite contaminated metal working fluids.

• Safety and Health at Work
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• v.1 no.2
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• pp.175-182
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• 2010

Objectives: This study examined how ethanolamines (EAs) with the same functional alcohol group ($HOCH_2CH_2$), such as mono-EA (MEA), di-EA (DEA), and tri-EA (TEA), in water-based metalworking fluids (wbMWFs) are vaporized, condensed, and transformed by heat generated during metalworking. Methods: Two types of experimental apparatus were manufactured to achieve these objectives. Results: Vaporization tests using a water bath showed that the vaporization rate increased markedly from $0.19\;mg/m^2{\cdot}min$ at $23.5^{\circ}C$ to $8.04\;mg/m^2{\cdot}min$ at $60^{\circ}C$. Chamber tests with a heat bulb revealed that "spiked" MEA was fully recovered, while only 13.32% of DEA and no TEA were recovered. Interestingly, non-spiked types of EAs were detected, indicating that heat could convert EAs with more alcohol groups (TEA or DEA) into other EAs with fewer group(s) (DEA or MEA). The EA composition in fresh fluid was 4% DEA, 66% TEA, and 30% MEA, and in used fluids (n = 5) was 12.4% DEA, 68% TEA, and 23% MEA. Conversion from TEA into DEA may therefore contribute to the DEA increment. Airborne TEA was not detected in 13 samples taken from the central coolant system and near a conveyor belt where no machining work was performed. The DEA concentration was $0.45\;mg/m^3$ in the only two samples from those locations. In contrast, airborne MEA was found in all samples (n = 53) regardless of the operation type. Conclusion: MEAs easily evaporated even when MWFs were applied, cleaned, refilled, and when they were in fluid storage tanks without any metalworking being performed. The conversion of TEA to DEA and MEA was found in the machining operations.