ABSTRACT Multicomponent composition and corresponding physical properties data of crude oils and petroleum products are needed as input to environmental fate simulations. Complete sets of such data, however, are not available in the literature due to the complexity and expense of making the measurements. Environment Canada has previously developed a database of various physical and chemical properties of crude oils and petroleum products. In this cooperative project, ten “typical” crude oils and refined products in common use or transport were identified for subsequent characterization. Measured oil physical properties include API gravity, density, sulphur content, water content, flash point, pour point, viscosity, surface and interfacial tension, adhesion, the equation for predicting evaporation, emulsion formation, and simulated boiling point distribution. The chemical composition of the oils are quantified for hydrocarbon groups, volatile organic compounds, n-alkane distribution, distribution of alkyla...