異氰酸鹽作業勞工呼吸健康初步調查研究

A Preliminary Survey on Respiratory Health of Workers Exposed to Isocynates

異氧酸鹽類的工業用途甚多，主要被用來作為 PU 樹脂之製造、塗料、黏著劑之 原料、發泡劑、合成纖維之塑質改善劑及生產塑膠製品及軟片等。有關國內目前之異 氧酸鹽使用狀況、暴露人數及危害情形等資料，迄今仍所知有限，因此本研究乃首先 針對全國異氧酸鹽類使用工廠，藉問卷方式調查 TDI 及 MDI 之使用狀況；並藉立意 取樣方式，選取七家臺灣南部地區工廠中之 243 位員工，進行工作前後的肺功能檢查、 肺部及皮膚理學檢查、填寫勞工健康問卷，並就現場做環境評估，以暸解暴露情形及 危害狀況。結果顯示國內目前約有至少 800 名的勞工暴露於異氧酸鹽類，而 TDI 及 MDI 之 年使用量各約為 4 814 及 33 096 公噸。另就調查之 243 位員工資料，發現暴露組（73 名）較非暴露組（170 名）有稍高的咳疾及喘鳴聲之比率；但在工作前肺功能測試而言， 暴露組與非暴露組則無顯著差異；然而若比較工作前與工作後之肺功能，則發現在 68 位工作前、後均完成測試者中，暴露組（58 名）之 FEV1，比非暴露組（10 名）差，而其 中更有 2 位（佔 2.45%）暴露組勞工，其 FEV1 各下降約 27%與 26%，符合職業性氣喘 之診斷原則。唯若考量可能的健康工人效應及可能會有延遲性氣道狹窄之反應，可推 估我國職業性氣喘罹患比例，應與國外之報告比例（5%～10%）為相近。本研究另檢測 73 位暴露組之勞工及 28 位對照組之勞工，有關淋巴球 eotaxin 反 應，結果發現暴露組有 3 位勞工呈現陽性反應，而非暴露組則皆呈陰性反應，唯此三 位均自訴在經過週日或假日休息後，回去上班時初始會有胸悶或呼吸困難等現象，然 均未出現喘鳴的表現，因此發現顯示 eotaxin 或可做為二異氧酸甲茉之暴露指標，然 其能否做為早期偵測，或預估勞工是否會引發氣喘症，則仍須進一步調查方能決定。 另本研究另亦嘗試利用暴露評估危害模式來評估勞工之暴露潛勢，然受限於樣本大小及實測暴露量之缺乏，僅 FEV1/FVC 及 FEV25-75%%發現與暴露潛勢及暴露年資有關。

Isocyanates are widely used in Polyurethane(PU) resin, paint, foam, and plastic manufacturing industries. However, the exposure and health-hazard data of workers exposed to isocyanate are rather limited in Taiwan. In this study, questionnaires were sent to 217 plants, which use TDI or MDI as raw materials. The result shows that annual the consumption rates of TDI and MDI are 4,814 and 33,096 metric tons respectively, and about 800 of workers are currently exposed to isocyanates. To evaluate the exposure and prevalence rate of occupational asthma caused by isocyanates, a filed study, combining questionnaire, lung function examination, and exposure assessment was conducted on 243 workers (including 73 of exposed group, and 170 of non-exposed group from 7 isocyanate-using industries). The result shows that the exposed group only has higher prevalence rates in terms of coughing and whining at the pre-shift of workdays. However, by comparing the differences of lung functions between the pre-shift and post-shift, the exposed group do have lower FEVl, and among them 2 workers have been found as occupational asthma cases. The test of T-cell responses to TDI-albumin conJugate also conducted in this study, which shows 3 out of 80 workers with positive reactions in eotaxin but normal in pulmonary function. This indicates eotaxin can serve as a exposure index for workers exposed to TDI. However, whether eotaxin can be used as an early indicator for asthma needs to be further studied. This study also discusses the use of exposure hazard assessment predictive model for developing the quantitative relationship between exposures and health-outcomes. Because of the limitation of sample size, only FEVl/FVC and FEV25-75%% have been found related to exposure hazard intensities and exposure duration.