The history of conservation efforts in Illinois falls into three stages. From 1850 to the 1930s, city and state parks were established and the beauty of Chicago's lakefront was successfully preserved. During the next stage, in the 1930s, federal intervention through the Civilian Conservation Corps and other agencies focused on upgrading park facilities and, most important, on reversing the severe erosion of soils, particularly in the hilly southern areas. Soil conservation laws took effect in 1937, and within a year the first soil conservation district was formed. By 1970, 98 districts, covering 44% of the state's farmland, promoted conservation cropping systems, contour plowing, and drainage.
The third stage of environmentalism began in the late 1960s, when Attorney General William J. Scott assumed the leadership of an antipollution campaign; he won suits against steel mills, sanitary districts, and utility companies, and secured passage of clean air and water legislation. The Illinois Environmental Protection Act of 1970 created the Pollution Control Board to set standards and conduct enforcement proceedings, and the Environmental Protection Agency (EPA) to establish a comprehensive program for protecting environmental quality. In 1980, the Department of Nuclear Safety was established. The federal EPA has also helped upgrade water and air quality in Illinois.
The years since the enactment of specific environmental laws and regulations have seen a noticeable improvement in environmental quality. Dirty air has become less prevalent. The Illinois EPA maintains more than 200 air-monitoring stations to measure different types of pollutants. Many of these stations are in the Chicago area. The agency also conducts about 2,500 facility inspections each year to verify compliance with air regulations. Since Illinois formerly produced about 6 million tons of hazardous wastes annually, the state agency tried to pinpoint and clean up abandoned hazardous waste sites. In 1984, Illinois began a three-year, $20 million program to eliminate the 22 worst sites and to evaluate nearly 1,000 other potential hazardous waste sites. Thanks to that program, over 60 sites were cleaned up by the mid-1990s. Progress has been made toward the voluntary cleanup of contaminated sites. In 1997, the Illinois General Assembly enacted a law developing a state underground storage tank program, and by May of that year over 14,800 releases from underground storage tanks have been reported, 5,800 of which have completed remediation under the new initiative. In 2003, the Environmental Protection Agency's database listed 455 hazardous waste sites, 39 of which were on the National Priorities List, in Illinois. In 2001, Illinois received $173,495,000 in federal grants from the EPA; EPA expenditures for procurement contracts in Illinois that year amounted to $17,833,000.