A study was conducted of available techniques for the biological treatment of oil and associated hydrocarbon contamination in soil and groundwater. The study involved a detailed literature search and review, as well as discussions with the users and developers of a number of the bioremediation techniques assessed. The result is a compendium of selected state-of-the-art bioremediation technologies which can serve to guide the selection process for treatment technology for a particular site subject to remediation. Background is provided on the various classes of sites on which petroleum-related contamination could occur, and the nature of contaminants typical of such sites. The mechanisms of hydrocarbon biodegradation are outlined along with various approaches to bioremediation such as in-situ, on-site, bioreactors, landfarming, composting, and physical/chemical treatments. Field trials required to characterize the site and provide an indication of the suitability of bioremediation and the most appropriate bioremediation approach are described. Commercially available bioremediation technologies are briefly discussed. A number of the bioremedial techniques reviewed are compared to more conventional treatment processes in terms of such criteria as operating cost, effectiveness, advantages, risks, applicability, equipment and manpower requirements, and considerations regarding usage in Canadian conditions. 15 figs., 17 tabs.