Risk Assessment for Metalworking Fluids and Respiratory Outcomes

BACKGROUND: Metalworking fluids (MWFs) are mixtures with inhalation exposures as mists, dusts, and vapors, and dermal exposure in the dispersed and bulk liquid phase. A quantitative risk assessment was performed for exposure to MWF and respiratory disease.METHODS: Risks associated with MWF were derived from published studies and NIOSH Health Hazard Evaluations, and lifetime risks were calculated. The outcomes analyzed included adult onset asthma, hypersensitivity pneumonitis, pulmonary function impairment, and reported symptoms. Incidence rates were compiled or estimated, and annual proportional loss of respiratory capacity was derived from cross-sectional assessments.RESULTS: A strong healthy worker survivor effect was present. New-onset asthma and hypersensitivity pneumonitis, at 0.1 mg/m3 MWF under continuous outbreak conditions, had a lifetime risk of 45%; if the associated microbiological conditions occur with only 5% prevalence, then the lifetime risk would be about 3%. At 0.1 mg/m3, the estimate of excess lifetime risk of attributable pulmonary impairment was 0.25%, which may have been underestimated by a factor of 5 or more by a strong healthy worker survivor effect. The symptom prevalence associated with respiratory impairment at 0.1 mg/m3 MWF was estimated to be 5% (published studies) and 21% (Health Hazard Evaluations).CONCLUSION: Significant risks of impairment and chronic disease occurred at 0.1 mg/m3 for MWFs in use mostly before 2000. Evolving MWFs contain new ingredients with uncharacterized long-term hazards.

IgG Antibodies Levels in Blood Serum of Workers Exposed to Microbial Contaminants of Metal Working Fluids

@#Introduction: Water-based metalworking fluid (MWF) provides a suitable environment for microbes to grow. This study aimed at identifying the level and species of microbial contamination of MWF in a metal machining factory and to determine the corresponding Immunoglobulin G (IgG) levels in the workers’ blood samples. Methods: Total of 298 workers in the production section of a metal machining factory, the production section using MWF as coolant fluid, were involved in this study. The Analytical Profile Index system was used to identify the species of microbes isolated from MWF bulk and air samples. Tryptone soya agar was used to incubate unknown bacteria, and sabouraud dextrose agar was used for unknown fungi. The level of IgG antibodies in workers’ blood were measured as an indicator of the exposure to the microbes isolated from MWF, corresponded to the microbial species isolated from MWF. Results: The most dominant microbes isolated from the channels were Candida albicans, Klebsiella pneumoniae, E. coli and Pseudomonas aeruginosa. A total of 21 (34.4%) workers were positively exposed to E. coli, 30 (42.2%) to Pseudomonas aeruginosa, and 45(75%) exposed to Candida albicans. Also, the mean level of optic density of IgG to Klebsiella pneumoniae was 0.415 (0.02). Conclusion: Water-based metalworking fluid in this metal machining factory was contaminated with bacteria and fungi. The workers in the production section were exposed to MWF as well as the microbes present in MWF. The level of IgG in blood was the biomarkers for occupational exposure to microbial contaminant MWF.

Vaporization and Conversion of Ethanolamines used in Metalworking Operations

OBJECTIVES: This study examined how ethanolamines (EAs) with the same functional alcohol group (HOCH2CH2), 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/m2.min at 23.5degrees C to 8.04 mg/m2.min at 60degrees 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/m3 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.

Occupational Dermatoses in Metalworking Fluid Exposed Workers . ( II ) Allergic Contact Dermatitis / 대한피부과학회지

BACKGROUND: Skin contact with metalworking fluid(MWF) remains a frequent cause of occupational dermatitis. However, no precise data is available about sensitization in metalworkers exposed to MWF in Korea. OBJECTIVES: The purpose of this study was to evaluate the prevalence of contact sensitivity among metalwokers who handle MWFs and to investigate the suitability of a screening test with MWFs being actually used in metalworkers. METHODS: An epidemiological study was performed using a'questionnaire in 771 workers in 9 derpartments of a motor company. 278 out of 771 workers had actual contact with MWF. Patch tests were performed in 73 metalworkers who had suspected dermatits in relation to exposure of MWF, which was selected via interviews and dermatologic examinations. Patch tests were included with a routine series of common components of MWF(materials obtained from Chemotechnique, Sweden), a solvent series and several dilutions of various crude MWFs(8 species) RESULTS: Contact sensitization was established in 14 metalworkers(5% of 278). Sensitising substances were biocide(6 cases), corrosion inhibitors(2 cases), emulsifiers(2 cases), biostatic substances(1 cses) and others(4 cases). Therefore 10 out of 14 metalworkers had true occupational allergic contact dermatitis. 10 out of 73 screening patch tests showed positive reactions to MWF elements, and 9 people who were positive to MWF elements showed positive reactions to crude MWF, but 1 person did not. CONCLUSION: The prevalence of occupational allergic contact dermatitis(3.5% of 278) was low. The screening patch test by crude MWFs actually used in metalworkers may give false negatives. Therefore for the purpose of diagnosis of allergic contact dermatitis, we need a process of patch tests with MWF elements.

Contact dermatitis among male workers exposed to metalworking fluids / 예방의학회지

In an epidemiological study of metal workers exposed to metalworking fluids(MWF), the prevalence time of evoultion, seasonal occurrence and clinical type of contact dermatitis were investigated. Composinal analyses of MWF with HPLC, dermatological examination and two consecutive questionnaire surveys were conducted. Study population was divided into two groups ; workers contact to cutting oil and workers contact to rust preventive oil. In the analysis of MWF, aliphatic hydrocarbons, having 12-20 carbons, was most common composition(49.04%) of cutting oil otherwise, major contents (90.99%) of the rust preventives oil were aliphatic hydrocarbons composed of 6-9 carbons. The frequency (point prevalence) of contact dermatitis(CD) was 7(12.7 per 100 subjects) in the dermatological examination of 55 workers. As the result of second survey for contact dermatitis, cumulative prevalence of oil working full-time and recent 1 year prevalence in two groups were 28.0, 16.7 and 15.1, 12.5 per 100 subjects. There were no difference in the prevalence of CD by oil, age, oil contact duration. Summer is the most common evolution season in workers exposed to cuttiogs, but not in workers exposed to rust preventive oil. Major clinical type of CD was erythematous papules in both groups. It presents the importance of preventive measures that 51.1% suffer from contact dermatitis had medical care at their own expense, and 47.1% of them felt serious about their contact dermatitis. From the fact that 68.6% think cotton gloves protective apparatus, we emphasize the need for health education.