Work-Related Hazards and Perceived Confined-Space Health Risk : Understanding the Correlation with Mental Workload Among Farmers in Northern Thailand’s Shallow Wells

Abstract

ABSTRACT Objectives This study examined factors related to perceived health risks in confined spaces (PCSHR) and their correlation with the mental workload among farmers managing agricultural wells in northern Thailand. Methods A cross-sectional, multi-stage sample of 356 farmers was selected from four rural districts’ agricultural areas. Data were collected through interviews conducted from August to December 2022, using a self-administered structured questionnaire. The five-part questionnaire gathered demographic data, information on experiences and operations in agricultural wells, knowledge of confined spaces, PCSHR, and the six-dimension NASA Task Load Index (TLX) mental workload. Linear regression and multi-variable analyses were used to investigate factors associated with PCSHR, while Pearson correlations tested the association between PCSHR and mental workload variables. Results Most farmers were male (92.4%), worked in wells to install pumping systems (81.7%) and maintain equipment (73.3%), averaging 3.80 times per year, with an average duration of 25.81 minutes. Physical symptoms reported included difficulty breathing (72.8%), feeling swelteringly hot (55.9%), and sweating excessively (27.8%), as well as accidents such as being struck by falling soil or objects (20.2%), and falling into the well while climbing down (14.9%). Farmers’ perceived risk scores were high when working while physically exhausted or unprepared and when assisting an unconscious worker without knowing the gas concentration. In addition, the maximal mental workload scores were mental demand and effort subscale. Factors significantly associated with PCSHR (adj.R 2  = 60.6%, p < .05) encompassed education higher than lower secondary level, current alcohol consumption, smaller well width, assisted operations, number of physical symptoms experienced, absence of environmental accidents, and confined space knowledge, while increased PCSHR was positively associated with mental workload (Overall r = 0.711, p < .01). Conclusion Comprehensive education about potential hazards can improve farmers’ risk perception, potentially reducing mental workload and preventing fatal accidents. Field studies are recommended to develop community-specific work protocols and accurate measuring instruments suitable for rural settings are needed.