Impact of heat stress on health-related symptoms and physiological changes among palm oil mill workers at Mukah, Sarawak

The palm oil industry is one of the most important sectors in the Malaysian economy. However, workers in palm oil mills (PO) are exposed to various health and safety hazards, including heat stress as PO is one of the main workplaces with high heat exposure. Heat stress occurs when a person's body cannot get rid of excess heat. The next stage is frequently fainting and, in extreme cases, death. Heat stress can cause heat stroke, heat rash, heat exhaustion, and heat cramps. It also leads to physiological and psychological changes, which can affect performance. The objective of this study is to determine the level of heat stress with physiological changes and health-related symptoms among workers in PO at Mukah, Sarawak. A total of 31 workers from four workstations were included in this study. Previous studies found that the highest ambient working temperatures in PO were in sterilization, boiler room, oil room, and engine room. The human resources division provided the names of the employees. Simple random sampling was used to choose the respondents from the list. The level of heat stress was measured using WBGT while the health-related symptoms and physiological changes was identified using a set of questionnaire and personal measurement, respectively. Data were then analyzed using SPSS Ver28. Results showed that boiler, engine and sterilizer workstation had high WBGTin, which caused moderate heat conditions. The maximum temperature was found in the sterilizer (28.6°C) and boiler (28.6°C). There was a significant difference found in BCT of boiler for before and after 8 hours shift (p<0.001). However, statistical analysis using Spearman Rho’s test showed that there is no correlation between heat stress level with physiological changes and health-related symptoms among study participants. To conclude, this study showed the heat stress levels in boiler, engine and sterilizer was exceeded the permissible limit of the ACGIH Threshold Limit Value (TLV). Although this study indicates that workers were not exposed to excessive heat, mitigating steps should still be taken to limit future heat exposure.