Three pesticides commonly used on farms and orchards throughout the West are jeopardizing the survival of Pacific salmon, the federal agency in charge of saving the fish from extinction has found.

Under the settlement of a lawsuit brought by anti-pesticide groups and salmon fishermen, NOAA Fisheries has issued a draft biological opinion that found the way chlorpyrifos, diazinon and malathion get into salmon streams at levels high enough to kill salmon protected by the Endangered Species Act.

The chemicals interfere with salmon's sense of smell, making it harder for them to avoid predators, find food, and even find their native spawning streams.

Banned from many household uses, tens of millions of pounds of the chemicals are still used throughout the range of Pacific salmon on a wide range of fruits, vegetables, forage crops, cotton, fence posts and livestock to control mosquitoes, flies, termites, boll weevils and other pests, according to NOAA Fisheries.

Jim Lecky, head of the office of protected resources for NOAA Fisheries Service, said his team has until a court-imposed deadline of Oct. 31 to work with the U.S. Environmental Protection Agency to find new ways to safely use the chemicals.

Lecky would not speculate whether the pesticides might ultimately be banned, but acknowledged that scientists have found that even with careful use under current guidelines, the chemicals are finding their way into streams at levels harmful to salmon.

The chemicals are the first of 37 that NOAA Fisheries and EPA must evaluate by 2012 under terms of a settlement reached last week in a lawsuit brought by Northwest Coalition Against Pesticides and the Pacific Coast Federation of Fishermen's Associations, which represents California commercial salmon fishermen.

A total of 28 species of Pacific salmon are classified as threatened or endangered from overfishing, dams, logging, grazing, urban development, pollution, irrigation, misguided hatchery practices and other threats.

Lecky said he could not say where pesticides rank in the threats to salmon, but eliminating the harm from pesticides would boost efforts to save them.