SACRAMENTO -- California violated the Clean Air Act when it decided nine years ago that no regulations were necessary to cut smog-forming compounds in farm and commercial pesticides, a federal judge ruled Wednesday.

U.S. District Judge Lawrence Karlton's decision means that lawyers for environmental groups and the state will meet to discuss possible remedies for the pollution. Lawyers for both groups have been ordered to file briefs in 20 days.

"The bottom line is that the state should have had regulations in place to have a 20 percent reduction of these emissions in five basins by this year," said plaintiffs' attorney Brent Newell of the Center on Race Poverty and the Environment.

Karlton said the California Department of Pesticide Regulation, the Air Resources Board, and the California Environmental Protection Agency violated the Clean Air Act in 1997 when they decided new rules weren't needed to reduce pollutants from pesticides.

The agencies were required by the U.S. Environmental Protection Agency in 1994 to adopt regulations that would cut the emissions from their 1990 levels by 20 percent in five California air basins, including the San Joaquin Valley, Sacramento and Ventura.

Instead, they asked pesticide producers to reformulate some of their products to reduce the ozone-depleting emissions, according to the ruling.

"In the absence of a state commitment to promulgate regulations based upon meaningful data, rather than an option to pass regulations, the statutory requirements (of the Clean Air Act) would not be met," the judge wrote.

In Wednesday's ruling, Karlton rejected a second claim alleging that the state intentionally manipulated baseline levels of pesticide components to avoid adopting the ozone regulations.

Glenn Brank, a spokesman for the Department of Pesticide Regulation, said the decision "rules in favor of DPR on one cause of action and rules in favor of the plaintiffs on another."

"Until our attorneys can analyze the ruling all we can say is that DPR is doing its best to comply with the law and air standards to protect Californians," Brank said.

The plaintiffs included Ventura Coastkeepers and Community and Children's Advocates Against Pesticide Poisoning.