This report represents the quarterly progress in a DOE/LPO sponsored program to identify additives to in situ steam processes which enhance oil production mechanisms or process control. The program is oriented toward site specific applications of additives to heavy oil and tar sand resources. Actual reservoir materials from California and Saskatchewan (heavy oils) and Utah and Alberta (tar sands) were utilized in experimental work. The program plan consists of three successive additive screening phases. The first screening phase, consisting of a literature review, identified additive applications to the specific resource candidates. The categories of selected additives included gases, solvents, surface active solvent, surfactants and reactive chemicals. Chemical and physical evaluations conducted during the second screening phase assessed additive performance at elevated temperatures and interactions with resource matrix, water and oil. Phase two screening has been completed for solvents, surface active solvents, surfactants and reactive chemicals and continues with gases. Additives demonstrating superior performance have been subjected to process simulations in unscaled physical models during the third and final screening phase. Additive enhancement of steam processes is established by comparisons with baseline evaluations without additives. The baseline evaluations with the four heavy oil and tar sand resources have been completed. Process simulations using surfactant and solvent additive have are in progress.