ERG worked with the National Energy Technology Lab and the University of Calgary to develop an expanded, open-source model that assesses air and water emissions from U.S. petroleum refineries. The Petroleum Refinery Life Cycle Inventory Model (PRELIM) enables users to evaluate how releases from refinery products and processes impact the environment over time. To support the expansion, ERG compiled emission and production estimates from U.S. Environmental Protection Agency and U.S. Energy Information Administration data sets. We also developed emission factors for refinery subprocesses that were then integrated into the model. Our results were recently published in a peer-reviewed article in Environmental Science & Technology.