Polar heteroatomic species have been correlated with storage instability problems in both petroleum- and shale-derived middle distillate fuels, Instability is defined as the formation of filterable sediments and gums. Heteroatoms (oxygen, nitrogen, and sulfur) have been found to be greatly enhanced in such sediments. Trace levels of certain organosulfur compounds have been found to significantly influence the deposit formation process. Findings that free-radical inhibitors were ineffective in controlling the stability of shale-derived middle distillate fuels posed the question : is free-radical chemistry the key to distillate fuel instability with respect to deposit formation? The effectiveness of organic amines as additives suggests that acid/base chemistry was also involved in the formation of deposits. This paper reports on a study of organosulfur compounds employed as dopants with naturally occurring peroxide compounds in fuels. The product distribution from the dopant and the change in peroxide concentration was monitored.