## 4 Conclusions  
Five different types of mantle were investigated in this study. The content of thorium in mantle M5 was found to be 50%, a value exceeding the highest levels reported in the existing literature. Mantle M5 recorded the highest thorium activity at 1.25 \(\times\) 10\({}^{4}\) Bq, exceeding the exemption limit for thorium of 1 \(\times\) 10\({}^{4}\) Bq adopted by the IAEA (2014). Further estimate has shown the dose equivalent on the surface of a single M5 mantle to be 0.68 \(\mu\)Sv/h, while on the surface of a package of six mantles it can increase to 1.9 \(\mu\)Sv/h. Two scenarios have been described, both showing that close contact with a package of M5 mantles can infer annual doses in excess of the dose constraint of 0.3 mSv/y from a single source, the second example inferring levels exceeding the permissible limit of 1 mSv/y for members of the public. Currently radioactive mantles are available for purchase without information concerning their radioactivity. Additionally, there is no impediment to the purchase of these in Malaysia, the country of present study. There is need to set criteria for the approving of thorium based lantern mantle products before their release for purchase and use by members of the public.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Time Exposure**} & \multicolumn{6}{c}{**Source Distance (cm) from Survey Meter**} \\ \cline{2-7}  & & **Surface** & **10** & **20** & **50** & **100** \\ \hline \multirow{4}{*}{1 mantle} & 1 h & 0.68 & 0.25 & 0.2 & 0.17 & BL * \\  & 4 h & 2.72 & 1 & 0.8 & 0.68 & BL \\  & 168 h & 114.2 & 42 & 33.6 & 28.6 & BL \\  & 720 h & 490 & 180 & 144 & 122.4 & BL \\ \hline \multirow{4}{*}{1 pack} & 1 h & 1.9 & 0.35 & 0.234 & 0.19 & BL \\  & 4 h & 7.6 & 1.4 & 0.936 & 0.76 & BL \\  & 168 h & 319.2 & 58.8 & 39.3 & 31.9 & BL \\  & 720 h & 1368 & 189 & 187.2 & 136.8 & BL \\ \hline \hline \end{tabular} BL.*: Background Level (0.1 \(\mu\)Sv/h).  
\end{table}
Table 6: Dose equivalent (\(\mu\)Sv per time exposure) measured with a survey meter (IdentiFinder 2) for mantle M5.  
**Author Contributions:** Conceptualization, Methodology, Investigation, Formal analysis, Writing--original draft, H.J.H.; Supervision, Funding, Conceptualization, Investigation, Writing--original draft, Formal analysis, S.H.; Investigation, M.S.M.S.; Writing--review and editing, D.A.B. and R.G.T.; Funding, Conceptualization, A.A., N.F.B., and R.M.T. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was supported by the Ministry of Science, Technology and Innovation (MOSTI) of Malaysia using Kumpulan Wang Amanah (KWA) Majlis Sains dan Penyelidikan Kebangsaan (MSPK). The authors gratefully acknowledge the Ministry of Higher Education Malaysia and Universiti Teknologi Malaysia through UTM High Impact Research Grant (No. 09G08). This study was also partially funded by contract research grant from Intelligent Science Sdn. Bhd. (RJ130000.7617.4C347). We acknowledge the cooperation with the project partners i.e., International Atomic Energy Agency and Atomic Energy Licensing Board, Malaysia for expert mission and procurement support through IAEA TC programme (MAL9018: Strengthening the Regulatory Infrastructure for Radiation and Nuclear Safety). [PERSON] acknowledges Taif University for financial assistance through Project number (TURSP-2020/163).  
**Conflicts of Interest:** There is no conflict of interest.