The effects of four common organic species (methanol, phenoxide, acetone, and methane) on the partitioning of iodine were studied over a range of concentrations, pHs, and radiation dose rates at ∼20°C. The primary goal of the study was to identify conditions leading to the production of significant quantities of volatile organic iodides. For all of the conditions studied, only the case of irradiated methane-iodine-air-water systems yielded sufficient volatile organic iodides to bring about decreases in the iodine partition coefficient.