在經濟發展的過程中，環境污染往往是其代價。石化產業在台灣經濟發展過程中扮演著火車頭的角色，帶動相關產業的勃興，但也帶來日益增加的環境污染與其社會爭議，成為政府部門必須面對的課題。在傳統的環境管制政策當中，科學評估被視為中立、理性客觀之分析技術，能夠有效處理環境問題的方法，其強調專業中立的形象，也與官僚理性所強調的中立性相似。因此這不僅是環境行政程序設計之核心，也是行政正當性的重要來源。但因著環境議題的複雜化、科學不確定性的增加，在行政程序當中，僅著重專家角色的行政程序，相信專家能夠帶來各樣問題的解答，不僅在程序上限制了多元知識類型的進入，既無法共同建構問題、也無法形成決策基礎的一部分；同時行政機關也此程序將決策責任移轉給專家；然而因著科學不確定性，使得專家必須在未知的情況下進行決策，因而使得決策內容會更加保守，讓環境爭議窄化成「如何收集更多資訊」等技術問題。行政機關原欲以專家作為決策正當性的來源，但狹隘的科學想像框架不僅使程序無法有效地處理環境爭議、無法回應來自多元參與者的提問，反而使得決策正當性更加受到嚴重的挑戰。 本研究以國光石化開發案的健康風險議題與六輕工安大火事件兩個案的環評過程為分析案例。在國光石化環評過程，健康風險議題是主要爭議焦點。當時有學者研究指出國光石化營運之後，將對台灣民眾的健康風險帶來重要影響，並指認環評書中所低估或錯估的部分。面對不同的科學研究爭議，環保署依其狹隘的科學框架，欲創制一套評判程序以解決爭議，卻適得其反。與此同時，六輕也在 2010年7 月傳出工安大火事件，地方陸續傳出有吳郭魚、文蛤、雛鴨等大量死亡的農業損失情事，使六輕營運後所造成的環境影響與健康風險問題，受到社會高度矚目。環保署因而要求台塑提出「環境影響調查報告書」進行審查。但環評專案小組因著科學不確定性而難以依科學論證作為基礎做出決策。最終則是以法院判決來作為決策的正當性來源。 本文透過多重資料來源的蒐集，包括田野訪談、環評專案小組會議、專家會議等相關之會議紀錄、相關事件的剪報資料，以及相關會議的參與觀察紀錄等。藉由兩個案的分析，探討行政程序建立在狹隘的科學框架之上時，為何產生行政決策的僵局，探討結構上的侷限與受到的正當性挑戰。並以論述應邁向具社會強健性的知識建構為基礎的開放行政程序，以強化決策正當性的根基。 / The scientific assessment in the traditional environment regulation policy is generally regarded as a rational technique. The common impression of scientific assessment is neutral and specialized, which is similar to the major principle of Bureaucracy, organization by functional specialty, defined by Max Weber. Therefore, the scientific assessment has been not only a foundation of environmental administration procedure, but also a resource of legitimacy. On the contrary, while the government just focuses on the scientific evidence in administrative procedure, there will be the political debates unable to resolve effectively. Because administrative procedure is unable to include multi-knowledge from different stakeholders, administration deal with environmental problems only limits to the sufficiency of scientific evidences. Consequently, administration transfers the responsibility about decision making to the experts committee. But experts committee could not make decision definitely, and the decision would be conservative, because of scientific uncertainty. As a result, the interpretation of environmental problems is narrowed to the proof of causal relationship between pollutants and environmental impacts. Since unknown causal relationships always exist, there will be ongoing arguments and disputes of environmental problems. Taking two examples of the environment impact assessment of a fire accident in the sixth naphtha cracking project in July, 2010, and the KuoKuang Petrochemical Project, 2011, the research analyze the hidden science framework and limitation behind the administrative procedure. The finding is that the technicalization of administration leads to government role shrinking and erodes the legitimacy of decision. In order to strengthen the foundation of legitimacy, administration should rebuild an open administrative procedure to foster socially robust knowledge.