Abstract: A method and apparatus for disposal of hazardous waste and other waste materials in salt formations is disclosed herein comprising the steps of: leaching out a cavity in a salt formation; installing a plurality of concentric disposed casings, one inside the other, down into the cavity and securing them in place; receiving the waste material in the form of organic and inorganic solids, semi solids liquids, sludges, hydrocarbons, solvents and waste water, separating the waste constituents and temporarily storing them in their respective storage tanks; transferring the waste material to a solification unit; solidifying the waste material and injecting said solidified materials down into the cavity within the salt formation; filtering the waste water through a series of filters prior to disposing of the waste water.