Effective pollution prevention is greatly facilitated by identifying and quantifying adverse effects to the environment during the product's life cycle, including raw material extraction and processing, manufacturing, use, recycling, and ultimate disposal. Life Cycle Inventory (LCI) analysis is a thorough procedure accounting for the environmental loads during the product life cycle. Through the detailed information gathered in LCI's one can identify the aspects of their plant/process that create the most significant environmental loads, and act to either substitute raw materials or modify process steps to reduce the generated environmental loads. In this paper, an LCI methodology which is generalized to account for environmental loads generated in all periods of operation (e.g., production, startup, shutdown, maintenance), as well as risk related events (e.g., accidents, off-spec. production, disposal of perishable materials) is presented. This methodology utilizes the eco-vector approach for tracking environmental loads. Recognizing that the scope and coverage of an LCI can vary substantially depending on goals and financial resources, our general LCI framework provides guidance for focusing on these aspects which are expected ro contribute the most significant environmental loads. The approach is demonstrated through a simplified example.