Accidents, spills, leaks, and past improper disposal and handling of hazardous materials and wastes have resulted in tens of thousands of sites across our country that have contaminated our land, water (groundwater and surface water), and air (indoor and outdoor). EPA and its state and territorial partners have developed a variety of cleanup programs to assess and, where necessary, clean up these contaminated sites. Cleanups may be done by EPA, other federal agencies, states or municipalities, or the company or party responsible for the contamination.