Montmorillonite is used in the oil drilling industry as a component of drilling mud, making the mud slurry viscous, which helps in keeping the drill bit cool and removing drilled solids. It is also used as a soil additive to hold soil water in drought-prone soils, used in the construction of earthen dams and levees, and to prevent the leakage of fluids. It is also used as a component of foundry sand and as a desiccant to remove moisture from air and gases.