Adequately preparing for and responding to terrestrial (land-based) chemical spills are critical to the protection of human health and the environment. To facilitate analysis and support decision-making for such events, the authors have developed an environmental risk management system that characterizes the ability of a spilled chemical to immediately impact human health, groundwater, surface water, and soil resources, and incorporates these four risk areas into an overall measure of terrestrial chemical risk. This system incorporates a risk index model, leverages geographic information systems (GIS) technology, and contains a comprehensive chemical and environmental database to assess and delineate the immediate threat posed by a terrestrial chemical spill. It is designed to serve a variety of stakeholders, including managers and policy-makers, who would benefit from generating screening-level environmental risk assessments without requiring a technical background or collection of detailed environmental and chemical data. Areas of potential application include transportation routing, industrial zoning, environmental regulatory compliance and enforcement, spill response, and security planning. (c) 2006 Elsevier B.V. All rights reserved.