Cause of Fish Kill	Number of US States Reporting It
Agriculture	24
Spills	17
Municipal Facilities	16
Industry	13
Land Disposal	6
Urban Runoff	4

Source: National Water Quality Inventory, 1988, Report to Congress, U.S. Environmental Protection Agency (EPA).

The table above shows the number of fish kills caused by several sources.  It then ranks the sources by the number of U.S. states in which they caused a fish kill.

Agriculture is easily the largest problem, followed by spills.  Spills of chemicals can wipe out large fish populations.

Other major sources include local governments and industries.  Sometimes industries will act in a manner that is not fully safe and protective of the environment in order to save money.