Fracturing creates or enlarges openings in rock or dense soil, such as clay, to help soil and groundwater cleanup methods work better. The openings, called “fractures,” become pathways through which contaminants in soil and groundwater can be treated “in situ” (in place) by injection or pumped aboveground for treatment. Although fractures can occur naturally in soil and rock, they are not always wide or long enough to easily reach underground contamination using cleanup methods. Fracturing can enlarge the cracks and create new ones to improve the speed and effectiveness of the cleanup. Fracturing is commonly used with several in situ cleanup methods.