A landfill is a large area of land or an excavated site that is designed and built to receive wastes. There were 3,536 active municipal landfills in the United States in 1995 according to the U.S. Environmental Protection Agency (EPA). Today, about 55 percent of America's trash (more than 220 million tons annually) is disposed of in landfills. Municipal solid-waste landfills (MSWLFs) accept only household, commercial, and nonhazardous industrial waste. Hazardous waste generated by industrial sources must be disposed of in special landfills that have even stricter controls than MSWLFs.

In the past, garbage was collected in open dumps. Most of these small and unsanitary dumps have been replaced by large, modern facilities that are designed, operated, and monitored according to strict federal and state regulations. These facilities may be distant from urban centers, requiring the large-scale transport of waste. About 2,300 municipal solid waste landfills were operating in the United States...