Developing a Health Risk Assessment Process of Workers Exposed to Chemicals in the Taiwanese Optoelectronic Semiconductor Industry

• Main Authors: Shao Zu Huang, 黃紹祖
• Other Authors: Kuen-Yuh Wu
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/80573639473785022096

碩士 === 國立臺灣大學 === 公共衛生碩士學位學程 === 103 === The objective of this study was to develop and demonstrate a health risk assessment process for use in the optoelectronic semiconductor industry to assess the potential health risks of chronic exposure to chemicals used in photolithography. Chemical control banding tool was first used to screen out high risk chemicals to be assessed. Human health risk assessment was conducted using the United States Environmental Protection Agency (U.S. EPA) risk assessment process. For exposure assessment, exposure modeling tool Stoffenmanager was used to predict an estimate of worker’s exposure given an exposure scenario. If the factory has collected personal sampling data, the information was used, along with the exposure model estimation as the prior distribution, to set up a Bayesian statistical update using Markov Chain Monte Carlo method. The updated distribution of the estimated exposure was then used to determine the hazard index (HI) of each compound. A photoresist had the greatest risk according to control banding. Its composition and by-products were determined by existing literatures and patents descriptions. Its main composition include Propylene glyco methyl ether acetate (also known as 1-Methoxy-2-propanyl acetate, or PGMEA), novolac resin, and photoactive compound (DNQ). Potential by-products of the photoresist include Phenol, Cresol, Benzene, Toluene, and Xylene. The dose response of each compound was re-assessed and updated when possible. Their reference concentrations and hazard indexes were determined. The resulting HIs and their 95th percentiles for each compound was 2.098 (95%: 6.59) for phenol, 11.08 (95%: 34.75) for benzene, 0.2868 (95%: 0.9025) for cresol, 0.13 (95%: 0.2628) for PGMEA, 0.02764 (95%: 0.087) for xylene, and 0.01021 (95%: 0.0.032) for toluene. Because PGMEA was the only compound that had sampling data, the HI of the other compounds were only ranked to determine compounds that should take precedence validation. Phenol and benzene in particular had the highest scores of HI and cancer risk, suggesting call for further validations.