# Occupational Inhalation Health Risk Assessment of TCE Exposure in the Korean Manufacturing Industry
## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Factor**} & \multirow{2}{*}{**Efficiency**} & \multicolumn{4}{c}{**Non-Carcinogenic Risks**} & \multicolumn{4}{c}{**Carcinogenic Risks**} \\ \cline{3-8}  & & **HQ for** & **HQ for** & **Ratio of** & **HQ for** & **HQ for** & **Ratio of** \\  & & **50\%\%\%** & **95\%\%** & **HQ \textgreater{1} \({}^{*}\)** & **50\%\%** & **95\%** & **HQ \textgreater{1} \({}^{*}\)** \\ \hline Air-purifying respirators (active carbon & & & & & & & \\ filter cartridge & 83\% & \(3.3\times 10^{-1}\) & 3.4 & 1.56 & 16.5 & 147.8 & 1.03 \\ Half face masks (active carbon filters) & 26\% & \(5.4\times 10^{-1}\) & 3.9 & 1.12 & 27.2 & 192.9 & 1.00 \\ Half mask respirator (twice-a-day & & & & & & & \\ cartridge exchange) & & & & & & & \\ Half mask respirator (once-a-month & & & & & & \\ cartridge exchange) & & & & & & & \\ \hline \hline \end{tabular}  
* Ratio of HQ \textgreater{1} (%) in the fabricated metal products industry and HQ \textgreater{1} (%) in the fabricated metal products industry with reduced TCE concentration.  
\end{table} 
Table 6: Scenario of risk reduction. cinogenesis in the degreasing group was 55%, while in the cleaning group, it was 50% [31]. A European study found that the average concentration of TCE in a metal degreasing workshop exceeded the MAK value, indicating an unacceptable risk with a hazard index of 1.68 [33]. In addition, a health risk assessment was conducted on 25 workers exposed to TCE in a computer cleaning department in Thailand. The HQ for non-carcinogenic effects among workers in the cleaning parts was 845, indicating an unacceptable risk [32]. The excess lifetime cancer risk for carcinogenicity is 0.162, indicating an unacceptable risk [32]. Regarding epidemiologic studies, 24 studies were included, such as a European study on the incidence of cancer in iron and metal industry degreasers using TCE and a US study on mortality in electrical, aerospace, and aircraft maintenance workers using TCE [65]. The incidences of kidney cancer, liver cancer, and non-Hodgkin's lymphoma among workers exposed to TCE were 1.27 times higher, 1.29 times higher, and 1.23 times higher, respectively [65]. According to [PERSON] et al., the risk of kidney cancer increases with TCE use for more than 13.5 years [30]. TCE was first recognized as an occupational cause of renal cell carcinoma in Korea in 2013, with cases of occupational death due to TCE in the workplace [66]. This study indicated that workers in the fabricated metal products industry are likely to be exposed to higher levels of TCE than workers in other industries. However, for workers exposed to TCE, the process is also a major factor in assessing risk. This aspect was not covered in this study, indicating the need for further research. Additionally, the literature review found that non-carcinogenic and cancer risk values from exposure to TCE in several countries exceeded acceptable levels, emphasizing the need for further action. However, the RfC standard values used to calculate risk in each country vary, which may lead to underestimation or overestimation of risk results. In this study, the exposure level in the manufacturing of fabricated metal products, the industry with the highest risk, was compared with the OEL in 2014, the measurement year of the WEMP, and the current OEL in Korea. Liver damage, accompanied by systemic skin diseases caused by TCE, has an immunological mechanism that can occur even at low concentrations. Internationally, cases of Stevens-Johnson syndrome due to exposure to TCE have been reported to occur at exposure levels below 50 ppm or, in a small number of workers, at exposure levels of less than 25 ppm [35; 67]. Measurements of three small cleaning workshops in Korea where Stevens-Johnson syndrome occurred revealed levels of 32.3 ppm and 21.97 ppm in Workplace 1, 30.08 ppm in Workplace 2, and 107.2 ppm in Workplace 3 [15]. TCE has been found to cause occupational diseases even at exposure levels lower than 50 ppm, Korea's permissible standard in 2014 [15].