My invention provides an oxidizing solution and process for the in situ oxidation of contaminants, including hydrocarbon, organic, bacterial, phosphonic acid, and other contaminants, the contaminants being found in various surfaces and media, including soil, sludge, and water. In a preferred embodiment, the solution includes a peroxygen compound, such as hydrogen peroxide, in solution with a pre-mixed solution of a carboxylic acid and a halogen salt, such as glycolic acid and sodium bromide, respectively.