Missouri's first conservation law, enacted in 1874, provided for a closed hunting season on deer and certain game birds. In 1936, the state established a Conservation Commission to protect the state's wildlife and forest resources. Today, Missouri's principal environmental protection agencies are the Department of Conservation, which manages the state forests and fish hatcheries and maintains wildlife refuges, the Department of Natural Resources, responsible for state parks, energy conservation, and environmental quality programs, including air pollution control, water purification, land reclamation, soil and water conservation, and solid and hazardous waste management. The State Environmental Improvement and Energy Resources Authority, within the Department of Natural Resources, is empowered to offer financial aid to any individual, business, institution, or governmental unit seeking to meet pollution control responsibilities.
An important environmental problem is soil erosion; the state loses 71 million tons of topsoil each year. Residents approved a 0.1% sales tax in 1984 and 1988 to create a fund to address this problem. As of 1982, 42 sites in Missouri were found to have unsafe concentrations of dioxin, a highly toxic by-product of hexachlorophene, manufactured in a Verona chemical plant; in that year, an evacuation was begun (completed in 1985) of the 2,000 residents of Times Beach, a community 30 mi (48 km) west of St. Louis that was declared a federal disaster area. St. Louis ranks high among US cities for the quantities of lead and suspended particles found in the atmosphere, but conditions improved between the mid-1970s and early 1980s.
In 2003, Missouri had 503 hazardous waste sites listed in the Environmental Protection Agency's database, 23 of which were on the National Priorities List. In 1996, it had 643,000 acres (260,000 hectares) of wetlands, or about 1.4% of the state's lands. In 2001, Missouri received $101,560,000 in federal grants from the Environmental Protection Agency; EPA expenditures for procurement contracts in Missouri that year amounted to $2,137,000.