環境風險評估即為環境評估的風險化，可視為環境評估工作的核心，這些評估工作可以包含環境影響評估、環境考量面鑑別、生命週期衝擊評估等。本研究根據英國環境食品農業事務部定義之環境風險評估，進而提出一個具有七個步驟的模糊風險評估系統之理論：(1) 問題描述：可以援引生命週期衝擊評估之概念來協助釐清危害來源、受體與效應之因果關係；(2) 危害嚴重性評估：以模糊邏輯 (fuzzy logic) 來模擬之；(3) 評估危害之發生機率：以模糊機率處理之；(4) 評估受體曝露於危害效應之機率：以模糊機率處理之；(5) 評估受體因為曝露危害造成損害發生之機率：以模糊機率處理之；(6) 評估損害之風險：利用模糊之四則運算之頂點法 (vertex method) 將上述之各項評估直整合計算成一風險值；(7) 評估風險之顯著性：風險之顯著性以多準則多關聯綜合評估法 (multi-criteria and multi-connection comprehensive assessment, MMCA) 來輔助決策。最後將以二個案例探討此理架構的適用性：案例一為某塑膠工廠擴廠之環境影響評估，而案例二為一土石方回收再利用處理廠，為了取得 ISO14001環境管理系統之認證，以該理論進行環境考量面鑑別。

The methods developed for evaluating risk provide a solid basis for environmental assessments, including environmental impact assessment, identification of environmental features, life cycle impact assessment and so on. In accordance with the steps of risk analysis developed by the Department of the Environment, Food and Rural Affairs of UK, this study proposes a seven-step fuzzy risk analysis method: (1) Hazard identification including sources of risk, receptors, effects and damage, with a life cycle impact assessment to help identify causal relationships; (2) Estimation of the severity of hazards, in which fuzzy logic is utilized to mimic the reasoning of assessors; (3) Estimation of the probability of hazards, in which fuzzy probability is used in situations for which no solid statistics are available; (4) Estimation of the probability of receptors being exposed to hazards. Considering the influence and the paths simultaneously exporting to receptors, probability is fuzzified in situations for which no solid statistics are available; (5) Estimation of the probability of harm resulting from exposure to hazards, in which probability is fuzzified in situations for which no solid statistics are available; (6) Estimation of the risk of harm. Vertex method was employed to aggregate the severity and fuzzy probability as a fuzzy risk score; (7) Evaluating the significance of risk. The significance of risk is assessed through multi-criteria and multi-connection comprehensive assessment (MMCA). In this paper, two case studies were used to demonstrate the practicality of this approach. The first case was an environmental impact assessment of a plastic manufacturing plant and the other was the identification of the environmental considerations associated with a recycling plant preparing for ISO14001 certification.