The California attorney general and Los Angeles city attorney filed a lawsuit yesterday against Mattel Inc., Toys "R" Us Inc. and 18 other companies, accusing them of making or selling products that contain "unlawful quantities of lead."

The move follows major recalls of toys, lunch boxes, children's jewelry and other goods during the last year by the U.S. Consumer Product Safety Commission in Washington.

The suit, filed in state court in Oakland under California's Proposition 65 law, would force manufacturers and retailers to adopt procedures for inspecting products to make sure they are safe. Barring that, they would be required to warn consumers that the items contained chemicals known to cause cancer or birth defects.

Mattel, the lead defendant in the lawsuit, said it welcomed the attorney general's involvement and added that it would be helpful for the entire toy industry. Shares of Mattel, based in El Segundo, Calif., fell 21 cents to $19.65 at 1:51 p.m. in New York Stock Exchange composite trading.

"Mattel expected this development and believes that the attorney general's assumption of this case will be beneficial to all parties," a spokeswoman for the El Segundo company said in a statement. "The company has been in continuous communication with the California attorney general's office since the initiation of the recalls this summer and has cooperated fully."

Proposition 65, a successful ballot initiative known as the Safe Drinking Water Enforcement Act of 1986, allows the state to collect civil penalties of as much as $2,500 for each of the millions of contaminated items.

"Obviously, they do not want to put warnings. They are going to eliminate the lead or eliminate the product," said Attorney General Jerry Brown. "But, going forward, we want to prevent these kind of things from happening."

Brown said he expected the companies to settle the lawsuit by agreeing to "conditions such as testing or putting independent monitors in foreign countries." Those measures would ensure that products contain no lead or other harmful chemicals when they are shipped from factories, he said.

Brown noted that Proposition 65 is proving to be a valuable tool to protect California and U.S. consumers from "the new world order where the global supply chain goes from Beverly Hills to the hinterlands of China" and where "some companies have closed their eyes" to the threat of contamination.

Lead has been listed by the state since 1987 as a toxic material that damages the nervous system and other organs. Lead paint has been banned in the United States since 1978 because of lead's link to brain and neurological problems, particularly in children. Toys are recalled every year for containing lead levels that exceed the legal standard of 600 parts per million. But this year's recalls hit consumers particularly hard, in part because they involved a series of well-known toys.

In June, toy maker RC2 Corp., one of the defendants in Brown's lawsuit, recalled 1.5 million of its wildly popular Thomas & Friends Wooden Railway sets. Mattel followed in August with a series of recalls of more than 2 million toy cars, trains, shape-sorters and Barbie doll accessories. Its Fisher-Price unit also pulled Sesame Street-themed products from a line of infant and preschool toys.

Brown's lawsuit, which has been joined by Los Angeles City Attorney Rocky Delgadillo, followed a series of legal notices sent to the state by private attorneys and environmental groups as authorized by Proposition 65. The law allows them to take action, if the government doesn't file its own complaint.

Environmental activists, who initiated legal action against manufacturers after sounding early warnings about lead-laced toys, said they were glad to see Brown and Delgadillo join the fray.

"We have the same goals for the toy companies to clean up their acts," said Charles Margulis, a spokesman for the Center for Environmental Health in Oakland. Consumers would be better protected by having more government oversight "as opposed to the voluntary testing," he said.

Last summer, many retailers announced a series of procedures to reassure the public about the safety of their products.

Mattel, the country's biggest toy company, announced its most stringent testing ever, including batch-testing every toy. Wal-Mart Stores Inc., Target Corp., Toys "R" Us and Walt Disney Co. announced expanded oversight, including independent third-party product safety reviews.