The nature of environmental risk is often determined by the location patterns of industrial firms in a locale. We develop a methodology for analyzing the capacity of toxics-generating industries to leave toxic residuals on the landscape, in the context of long-term master planning. To understand an area's risk profile, we first characterize the location pattern of risk-generating firms and develop ways to represent the risk potentials of these shapes. To this end, we develop a geometric approach for characterizing the spatial patterns of these clusters of dirty industries, using new measures for analyzing spatial densities and compactness. We then introduce context (i.e. actual zoning patterns, transportation corridors) and explain how this relates to the spatial patterns found. We illustrate this analytical method with application to Orange County, California, USA and point out how it affords a deeper understanding of the connections between industry and environmental risk. We end the article with a discussion of how these analytical methods might be used for land use planning.