A survey for rhinitis in an automotive ring manufacturing plant

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.

Occupational rhinitis and asthma: where do we stand, where do we go?

This review provides an overview of current and emerging issues regarding occupational rhinitis (OR) and occupational asthma (OA), focusing on studies discussing concepts and results that are relevant to both diseases. OA and OR are conditions that affect the upper and lower airways, are characterized by reduced airway caliber and hyperresponsiveness and by inflammation, and are caused by agents present in the workplace. To explain disease expression, research is moving from the T-helper type 1/type 2 cells paradigm to consider the contribution of diverse alternative pathways such as neural inflammation, a dysfunctional epithelial barrier, and autoimmune mechanisms, among others. Objective assessment of OR and OA has been improved and tested for research and, currently, clinical application. Further developments in the field of OR are expected to lead to more generalized clinical applications, following the example of what has been achieved for OA.

Respiratory symptoms and exposure-response relations in workers exposed to metalworking fluid aerosols

The aim of the study was to identify specific health risks and exposure-response relationships associated with exposure to metalworking fluid (MWF) aerosols. In a cross-sectional study of machine workers exposed to MWF aerosols in five companies in Sweden, a self-administered questionnaire about health symptoms, work tasks, and exposure situations was sent out to 2294 employees, 1632 exposed and 662 referents. Referents were office workers and metal workers not working with MWFs. In four of the companies, there were recent measurements of personal exposure to MWF aerosols. Log-binomial regression models were used to estimate prevalence ratios with 95% confidence intervals for different health outcomes in relation to different variables of exposure. The response rate after two reminders was 67% resulting in 1048 (923 male, 125 female) workers exposed to MWF aerosols and 451 (374 male, 77 female) referents. The study indicates that metal workers in Sweden currently exposed to a mean value of MWF aerosols of 0.4 mg m(-3) have a significantly higher prevalence of wheeze, chronic bronchitis, chronic rhinitis, and eye irritation compared to the referents. At a mean exposure of 0.4 mg m(-3), a level below the Swedish 8-h exposure limit value of 1 mg m(-3), machine operators showed increased prevalence of symptoms in eyes and airways. Thus, the current exposure limit value does not seem to protect the workers from such symptoms.