WASHINGTON, Sept. 11 (UPI) -- Additional restrictions on three pesticides will help protect salmon in four western states, the U.S. Environmental Protection Agency said Friday.

Changes in the use of three organophosphate pesticides -- chlorpyrifos, diazinon and malathion -- should keep water cleaner in California, Idaho, Oregon and Washington, EPA officials said in a release.

The changes, to be noted on product labels, include the addition of pesticide buffer zones and application limits based on wind speed, soil moisture and weather conditions, said Steve Owens, EPA assistant administrator for prevention, pesticides and toxic substances.

Chlorpyrifos, diazinon and malathion are made by Dow Chemical, Cheminova and Makhteshim Agan of North America, respectively.

The new restrictions, developed in consultation between the EPA and the National Marine Fisheries Services, apply to surface waters used by 28 salmon and steelhead species in the four states.

The EPA and the fisheries service are to monitor the effectiveness of the restrictions on fish populations.