Fixation/stabilization is a chemical process that uses a re-agent to transform soil contaminated with soluble heavy metals into insoluble non-hazardous material. The reduction in solubility minimizes the migration and leaching of contaminants from the soil.

Fixation is also effective in the solidification of heavy hydrocarbons, PCBs, tars, and sludge materials. The process is traditionally completed in a pug mill, where precise quantities of soil and reagents are mixed with water to initiate the chemical reaction. The material is then stockpiles in a curing area where the reaction continues over several days.

Once curing is complete, the material is tested to confirm the treatment's effectiveness. Under the right conditions, chemical fixation can be a cost effective treatment method that often provides the following advantages: high throughput, short processing periods, regulatory acceptance (variable by state), reduction in volume of end-product, and reduced long-term liability.