Abstract: A method of immobilizing a hazardous waste is provided. The method comprises providing a dry cementitious composition capable of hardening and in the form of finely divided particles of at least one cement binder, placing an amount of the dry cementitious composition into the hazardous waste with or without an additional added volume of water, without any type of physical mixing of the cementitious composition and water other than the mixing which occurs merely by applying the cementitious composition into the water. The major portion of the particles of the cementitious composition have approximately the same drop rate through the volume of water. The water contacts the dry cementitious composition when poured into the volume of water to hydrate the particles of the dry cementitious composition, the particles of cementitious composition dropping through the water to displace excess water and form the hydrated cementitious composition particles in a substantially non-segregated mass.