South Africa has rich coal deposits concentrated in the northeast of the country, and as a result, most of the country's coal mining is located in this region. Two of the principal coalfields exploited are the Witbank and Highveld coalfields, located in the Mpumalanga province. Coal contains trace quantities of the naturally occurring radionuclides whose mass concentration can be enhanced by anthropogenic activity. The radioactive fallout from these activities could lead to elevated radon concentrations indoors. Two towns, Secunda and eMalahleni, were identified due to their proximity to coal-based industries. A previous study investigated whether these industries caused elevated radon levels in Secunda homes but found a lower-than-expected average concentration of 76.4 ± 7.6 Bq m-3. This was attributed to either the prevailing wind depositing the radioactive fallout to neighboring towns, such as eMalahleni, or the type of industrial activity. This paper builds on this study by investigating whether elevated radon levels are found in homes in eMalahleni. Measurements were performed in 22 homes during December 2019, and the average indoor radon concentration was calculated as 122.1 ± 8.5 Bq m-3. The cause of these elevated levels was then investigated, and it was found that even though the coal industry contributes to elevated radon levels, the town's underlying geology seems to be the primary contributor.
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