• Safety and Health at Work
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• 제3권1호
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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.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2004년도 International Conference Global Environmental Problems and their Health Consequences
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• pp.217-222
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• 2004

This study was conducted to estimate if the level of several chemical ingredients including alkanolamines or ethanolamines (EA) examined in the specific synthetic metalworking fluid (MWF) ‘A’ can cause anti-microbial activity and health effect. Three water-based MWF products (‘A’, ‘B’, and ‘C’) were studied every week for two months. Chemical ingredients such as formaldehyde, boron, EA, and copper were examined. In the sump where MWF ‘A’ was used, not only the total level of EA, monoethanolamine(MEA), diethanolamine(DEA) and triethanolamine(TEA), but also boron level were significantly higher than those of the other MWFs. ANOVA statistical tests indicated that levels of pH, alkalinity, boron, MEA, DEA and TEA in MWF ‘A’ were significantly higher than those in other MWF types. Correlation tests also found that levels of pH, alkalinity, boron, MEA, DEA and TEA in MWF ‘A’ are significantly correlated. We suggested the assumptions that excessive concentrations of EA, and borate at a high pH level, may cause anti-microbial resistance synergically. To demonstrate this assumption, additional study is needed to examine the relationship between the levels of microbes and excessive concentrations of EA, and borate at a high pH level.

• KSTLE International Journal
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• 제4권2호
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• pp.52-55
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• 2003

This study was conducted to estimate if the level of several chemical ingredients including alkanolamines or ethanolamines (EA) examined in the specific synthetic metalworking fluid (MWF) "A" can cause anti-microbial activity and health effect. Three water-based MWF products ("A", "B", and "C") were studied every week for two months (from June 1, 2002 to July 30, 2002). Chemical ingredients such as formaldehyde, boron, EA, and copper were examined. In the sump where MWF "A" was used, not only the total level of EA, monoethanolamine(MEA), diethanolamine(DEA) and triethanolamine(TEA), but also boron level were significantly higher than those of the other MWFs. ANOVA statistical tests indicated that levels of pH, alkalinity, boron, MEA, DEA and TEA in MWF "A" were significantly higher than those in other MWF types. Correlation tests also found that levels of pH, alkalinity, boron, MEA, DEA and TEA in MWF "A" are significantly correlated. We suggested the assumptions that excessive concentrations of EA, and borate at a high pH level, may cause anti-microbial resistance synergically. To demonstrate this assumption, additional study is needed to examine the relationship between the levels of microbes and excessive concentrations of EA, and borate at a high pH level.

• 한국산업보건학회지
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• 제15권3호
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• pp.270-276
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• 2005

This study was conducted to examine whether a specific synthetic metalworking fluid (MWF), "A", in use for 10 months without replacement, displayed microbial resistance and to identify the additives associated with the control of microbial growth. Three synthetic MWF products ("A", "B", and "C") were studied every week for two months. Microbial deterioration of the fluids was assessed through evaluation by endotoxin, bacteria and fungi levels in the MWFs. In addition, formaldehyde, boron, ethanolamine, and copper levels were also studied to determine whether they influence microbial growth in water-based MWFs. Throughout the entire study in the sump where MWF "A" was used, bacteria counts were lower than 103 CFU/mL, and endotoxins never exceeded 103 EU/mL. These levels were significantly lower than levels observed in sumps badly deteriorated with microbes. Boron levels in MWF "A" ranged from 91.7 to 129.6 ppm, which was significantly higher than boron levels found in other MWF products. The total level of ethanolamine (EA) in MWF "A" ranged from 35,595 to 57,857 ppm (average 40,903 ppm), which was over ten times higher than that found in other MWFs. Monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA) concentrations in MWF "A" were also significantly higher than seen in other MWFs. However, although EA and boron might improve anti-microbial performance, their abuse can pose a serious risk to workers who handle MWFs. From an industrial hygiene perspective, our study results stress that the positive synergistic effect of boron and EA in reducing microbial activity in MWF must be balanced with the potentially negative health effects of such additives. Our study also addresses the disadvantage of failing to comprehensively report MWF additives on Material Safety Data Sheets (MSDS). Future research in MWF formulation is needed to find the best level of EA and boron for achieving optimal synergistic anti-microbial effects while minimizing employee health hazards.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2003년도 Challenges and Achievements in Environmental Health
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• pp.213-216
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• 2003

This study was conducted to estimate if the level of several chemical ingredients including alkanolamines or ethanolamines (EA) examined in the specific synthetic metalworking fluid (MWF) “A” can cause anti-microbial activity and health effect. Three water-based MWF products (“A”, “B”, and “C”) were studied every week for two months (from June 1, 2002 to July 30, 2002). Chemical ingredients such as formaldehyde, boron, EA, and copper were examined. In the sump where MWF “A” was used, not only the total level of EA, monoethanolamine(MEA), diethanolamine(DEA) and triethanolamine(TEA), but also boron level were significantly higher than those of the other MWFs. ANOVA statistical tests indicated that levels of pH, alkalinity, boron, MEA, DEA and TEA in MWF A were significantly higher than those in other MWF types. Correlation tests also found that levels of pH, alkalinity, boron, MEA, DEA and TEA in MWF “A” are significantly correlated. We suggested the assumptions that excessive concentrations of EA, and borate at a high pH level, may cause anti-microbial resistance synergically, To demonstrate this assumption, additional study is needed to examine the relationship between the levels of microbes and excessive concentrations of EA, and borate at a high pH level.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2005년도 국제학술대회
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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

• 한국산업보건학회지
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• 제15권1호
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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% .

• 한국산업보건학회지
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• 제23권3호
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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.

• Safety and Health at Work
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• 제1권2호
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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.

• 한국산업보건학회지
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• 제17권4호
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• pp.282-288
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• 2007

그 동안 많은 역학연구를 통해서 금속가공유(metalworking fluid, MWFs) 노출과 여러 조직에서 암 발생 위험과의 관계를 밝혔지만, 금속가공유 종류(비수용성, 수용성, 합성, 준합성)별로 구분된 위험은 아직 완전하게 규명되지 않았다. 역학조사에서 금속가공유 노출을 대체할 수 있는 인자(surrogate)로서 정성적(qualitative), 명목적(ordinal) 혹은 준정량적인(semi-quantitative) 변수들(금속가공유에 대한 노출 유무, 노출 정도: 높음, 낮음 등, 직업 유무, 근무기간 등)을 이용하여 금속가공유 노출을 평가하였다. 이러한 노출평가방법은 기본적으로 금속가공유 노출 강도(intensity)가 고려되지 않을 뿐만 아니라 노출 분류 오류(misclassification)도 항상 존재할 수 있어 금속가공유 노출은 물론이고 종류별 위험을 밝히기 어렵다. 일부 역학연구에서 금속가공유 종류별 누적 노출양(cumulative exposure level)과 암위험과의 관계를 밝혔다. 이러한 연구결과들은 모두 금속가공유 종류별로 과거노출을 추정할 수 있는 자료(정량적인 노출평가자료, 과거직업력, 취급했던 금속가공유 종류 등)가 잘 기록되어 있는 1개의 대규모 자동차공장에서 나온 것들이다. 따라서 금속가공유에 대한 노출자료가 부족하고 사용특성에 대한 기록이 없거나 부족한 일반 인구나 산업을 대상으로 한 역학연구에서는 금속가공유의 종류별 위험을 밝히는것은 불가능하다. 금속가공유 종류별로 과거 노출에 대한 확률(probability)을 추정하는데 일반적으로 활용할 수 있는 노출확률 메트릭스를 개발하는 것이 필요하다.