Relative Risk Assessment of Irritating Effects in Occupational Exposure to Metalworking Fluids Mists in Selected Lathes in Tehran

Occupational exposure to metalworking fluid mist causes respiratory irritation. This study aimed to assess the relative risk of irritating effects in occupational exposure to metalworking fluids of lathe process.

Sixty-five subjects exposed to oil mist as exposed group and 65 administrative staff of the same industry as control group were selected. Health and Safety Executive/Health and Safety Laboratory (HSE/HSL) questionnaire was used for irritating effects. The US National Institutes of Health and Safety (NIOSH) method 5026 was used to monitoring respiratory exposure to oil mist. We also calculated the relative risk of irritating symptoms using MedCalc software. The study was approved by the ethics committee and conducted with the consent of participants.

The mean time-weighted exposure to mineral oil mist in lathe workers was 7.10±3.49 mg/m3. The amount of throat irritation in machinists was significantly higher than the control group (p-value = 0.044).The relative risk of irritating effects in the eyes, nose, mouth and throat in machinists is slightly higher than control subjects (p-value = 0.05).

In this study, the occupational exposure in 67% of lathe workers is higher than recommended exposure limit in Iran. Subjects by oil mists exposure represented a risk of irritating effects in the respiratory tract, especially the throat. For this reason, continuous assessment and control of exposure is are needed to reduce the risk of chronic diseases.