Exposure Risk Assessment of Harmful Chemicals upon Tank Cleaning Worker of Phenol-formaldehyde Resins Reactor

[[abstract]]酚醛樹脂(PFR)為廣泛應用於印刷電路基板、黏著劑、電木粉及塗料等製造，由於其優異電氣絕緣性、耐磨耗性、耐高溫性能，業已成為工業上不可或缺的材料之一；由全國合成樹酯年產量統計資料顯示，PFR年產量名列所有合成樹脂之前五位，且有逐年攀升之趨勢，因此對於PFR聚合製造與生產中相關槽體清洗作業人員之職業暴露危害評估，實值得重視與研究。 本研究以國內某一知名酚醛樹酯生產大廠為研究對象，試圖以工業安全與職業衛生的角度，進行合成樹脂業批次生產之清槽作業危害評估與暴露研究之探討，包括反應器清洗作業有害氣體量測方式、通風換氣方式之適宜性與理想通風換氣時間之探討、反應槽內真實暴露濃度變化情形及健康風險評估等，供相關清槽作業程序及管理改善之依據。 本研究採樣分析結果顯示，倘祇測定單側氣體濃度，應可視為另一側之有害性氣體濃度，另為符合作業場所法定容許濃度標準及使人員免於低濃度健康危害暴露，建議清槽作業場所應全程施予通風換氣，如礙於經費或空間等限制，則應超過26小時為宜且不得低於15小時，其中應儘可能隨時監測甲醛濃度，避免尖峰濃度過高威脅人員作業。 吸入暴露之健康風險評估結果顯示，工作30年甲醛之致癌風險，遠超過一般人可接受的風險值，而綜合危害指數（HI）皆小於1，屬於可接受範圍。 酚醛樹脂反應釜清槽作業逸散之化學物質中，甲醛偵測之濃度除高於法令容許濃度外，部分亦超過行動濃度0.5PEL，故清槽作業健康暴露風險應以甲醛為主要危害物質，惟甲醛目前尚未列入「勞工作業環境測定實施辦法」中定期實施作業環境測定項目，建議應考慮將甲醛列入作業環境測定項目中實行，並期望本研究可供政府做為加強職業病預防之重要資訊。[[abstract]]Phenol-formaldehyde resins (PFR) is a kind of resin material which be used in the industrial fields as manufacturing printed circuit board, adhesive, bakelite powder ,and dope etc.. Because PFR has good electrical insulation, wear resistance and can keep properties under high temperature, which holds quite important position in the chemical industry in our country. According to the statistic information , PFR came out to 5th in all compounded resins and indicates increasing current year after year. Therefore it is worthy of paying attention on and research about the professional exposure harmful risk assessment upon the similar tank cleaning workers when polymerize, manufacture PFR. This research was made combined theory and practice, taking a big famous PFR manufacture factory as its objective, tying to discuss a series harm estimate and exposition research upon batch production of tank cleaning works in compounded resin industry under the aspects of industry safety and professional hygiene and to estimate the suitability of measuring harmful gas and ventilation methods and suggested ideal ventilation time when clean the reactor, as well as indicate the relationship between the true exposure concentration, measuring methods for gas concentration and health risk assessment etc. in the similar reactor tank cleaning for providing the foundation to revise the interrelated cleaning procedures and improve operation management. This study indicated results of sampling analysis, the concentrations measured under different height of both left and right sides all were different from the statistics, therefore the concentration of harmful gas could be measured. According to the results of experimental design in this research, Therefore in order to accord with the concentration standard permitted under the laws for the working place for avoiding the workers from exposure harm to health under low concentration, we suggest similar reactor tank cleaning should take ventilation in the whole course as soon as possible, and it should be better exceeding for 26 hours and not less 15 hours if for the limitation of funds or space, in which should monitor the concentration of formaldehyde at any moment as soon as possible to avoid the exorbitant concentration menacing the workers from working. The health risk assessment based on the assessment on inhalation , result show that among work 30 years, the cancerous risk of formaldehyde is furthermore than common people acceptable risk .and mix heat index are all less than 1,belongs to acceptable range. The chemical materials of PFR reaction were vaporized during the reactor tank cleaning, in which the concentration of formaldehyde sensed except exceeded the concentration permitted under the laws, some also exceeded 0.5 PEL than working concentration, so as to which was the main harmful material of health exposure risk when reactor tank cleaning. Because only above mentioned materials except toluene were not listed on [Regulation of Measurement for Labor Working Environment] as the items measured regularly, and we suggest to list formaldehyde as the items of measurement of working environment and expect this research could be as the important information to strengthen professional disease prevention for our government