An intervention of Safety chemical program to reduce occupational exposure and improve health among BMA Vector Control Operators

Abstract

Objective: 1) To assess the current occupational chemicals exposure and the relationship of the between workers' health condition and their exposure from spraying chemicals among Vector Control Operators (VCOs) in Bangkok, Thailand: 2) to determine the effectiveness of a chemical safety intervention program designed to increase chemical behavior safety score, reduce occupational chemical exposure, health symptoms prevalence, and spirometric lung function impairment. Methods: A quasi-experimental study was conducted in six Bangkok areas among 96 male operators with two follow-ups time by measured every six months. The operators were divided into two groups: the intervention group received intervention, and the control did not. General information of participants including personal behavior, environmental working condition and health symptoms were collected through face to face by using valid questionnaires. Exposure to cypermethrin, benzene and toluene were collected by using personal solid sorbent sampling during the time of chemical spraying by NIOSH method. Urine samples were collected to evaluate biological exposure as pollutant metabolite levels. The data were analyzed by using descriptive statistics and multiple logistic regressions for test association. Overall intervention effects were assessed by repeated-measure analysis of variance (ANOVA). Linear mixed models (continuous outcomes), and generalized linear models with generalized estimating equations (GEE) (dichotomous outcomes) were used to measure and assess intervention effects at specific follow-up times (follow-up 1 and follow-up 2). Results: Average participant age was 41.76±10.21 years (mean ± SD). The exposure level of benzene was 0.120±0.86 mg/m3 or 0.37±0.26 ppm, a figure greater than National Institute for Occupational Safety and Health (NIOSH) recommendations (NIOSH REL) Ca TWA 0.1 ppm. The results demonstrated that facial irritation, blurred vision, fatigue, and nausea were significantly associated with airborne, biomarkers. Irregular use of personal protective equipment (PPE), especially when spraying indoors (OR 1.46, CI 0.52-4.67, p<0.05), and poor use of PPE among operators may increase health risks (OR 6.08, CI 1.61 22.9, p<0.05). At the baseline measure, both groups had similar sociodemographic characteristics, personal habits, and environmental working conditions. After the intervention program, the intervention group had effectively reduced difference means occupational exposure for 3-phenoxybenzoic acid (3-PBA), trans, trans-muconic acid (tt-MA) and o-cresol. For effectiveness of intervention to reduce symptoms prevalence and chemical safety score, there were also high statistically significant differences between the groups at follow-ups 1 and 2, particularly had reduced eye and facial symptoms (facial burning, paresthesia, blurred vision), skin symptoms (rash/itchy skin) at during working and after working. However, this intervention was not associated with a beneficial effect on lung function. Conclusion: The findings suggest that the introduction and implementation of chemical safety programs could reduce biological exposure, symptoms prevalence and improve chemical safety behavior among VCOs that lead to prevent health symptoms due to chemical exposure. Further research is required to explain the findings regarding lung function.