Early conservation efforts in Ohio were aimed at controlling the ravages of spring floods and preventing soil erosion. After the Miami River floods of March 1913, which took 361 lives and resulted in property losses of more than $100 million in Dayton alone, the Miami Conservancy District was formed; five earth dams and 60 mi (97 km) of river levees were completed by 1922, at a cost of $40 million, to hold back cresting water. In the Muskingum Conservancy District in eastern Ohio, construction of flood-control dams has prevented spring flooding and the washing away of valuable topsoil into the Ohio River.
In recent years, the state's major environmental concerns have been to reverse the pollution of Lake Erie, control the air pollution attributable to industries and automobiles, clean up dumps for solid and hazardous wastes, improve water quality, and prevent pollution. Of recent concern is the problem with socalled "brownfields"—polluted industrial sites whose cleanup costs present barriers to development. In November 2000, voters approved the Clean Ohio Fund; it will provide $200 million to help revitalize abandoned commercial and industrial sites, promoting reuse of existing infrastructure, and helping to reduce sprawl. The Clean Ohio Revitalization Fund awarded nearly $40 million to 17 projects in its first round of funding.
The state's regulatory agency for environmental matters is the Ohio Environmental Protection Agency (EPA), established in 1972. The agency has long-range programs to deal with pollution of air, water, and land resources. Ohio EPA also coordinates state, local, and federal funding of environmental programs. In 2001, Ohio received $73,963,000 in federal grants from the EPA; EPA expenditures for procurement contracts in Ohio that year amounted to $59,880,000.
Since 1972, antipollution efforts in Lake Erie have focused on reducing the discharge of phosphorus into the lake from sewage and agricultural wastes; sewage treatment facilities have been upgraded with the aid of more than $750 million in federal grants, and efforts have been made to promote reduced-tillage farming to control runoff. By the early 1980s, numerous beaches had been reopened, and sport fishing was once again on the increase. Since 1972, Ohio industries spent billions of dollars on efforts to control air pollution. Peak ozone levels have dropped by 25% overall and by up to 50% in some urban areas. Lead levels in the outdoor air have dropped 98% since 1978 and particulate levels have dropped 80%. From 1967 to 1983, through the efforts of local health departments and with the eventual help of the EPA, over 1,300 open garbage dumps were closed down and more than 200 sanitary landfills constructed to replace them.
In 1980, Ohio passed its first legislation aimed at controlling hazardous wastes, and by the mid-1980s, with the aid of more than $11 million in federal Superfund grants, cleanup had been completed or begun at 16 major sites. In 2003, Ohio had 318 hazardous waste sites listed in the Environmental Protection Agency's database, 28 of which were on the National Priorities List.
Another agency, the Ohio Department of Natural Resources, is responsible for the development and use of the state's natural resources. The state's parks and recreational areas totaled 208,000 acres (84,000 hectares). The department also assists in soil conservation, issues permits for dams, promotes conservation of oil and gas, and allocates strip-mining licenses.