Wal-Mart Stores Inc.'s trash is now the federal government's treasure.

Yesterday, the world's largest retailer agreed to pay $81.63 million to the government after it pleaded guilty to criminal charges related to the illegal dumping of hazardous materials. Prosecutors say the retailer improperly disposed of pollutants such as bleach, fertilizer and pesticides at its stores from at least 2002 to 2006.

According to the Justice Department, Wal-Mart has pleaded guilty to Clean Water Act violations in California and Federal Insecticide, Fungicide and Rodenticide Act violations in Kansas City, Mo.