The sides failed to agree on a contract to replace one that expired Wednesday afternoon. Talks continued in Minneapolis, but union leaders rejected a new proposal and workers walked out late Wednesday.
Round-the-clock picketing began at plants in Washington, Louisiana and Ohio as Kaiser resumed manufacturing operations with replacement workers, salaried employees and retirees.
No new talks were scheduled, though both sides indicated they were open to resuming negotiations that began Sept. 1.
The contract covered union members at five plants. Two are in the Spokane area and the others are in Tacoma, Gramercy, La., and Newark, Ohio.
The union contends Kaiser's wages and benefits are below industry averages because workers agreed to wage and pension concessions to help the company weather rough spots in the 1980s.
Steelworkers spokesman John Duray said the latest company proposal "did not offer anything that addressed the real needs that our people have expressed for quite a long time." Duray also said the company wanted to eliminate 400 jobs.
Kaiser president Ray Milchovich said the company's offer "not only improved the standard of living" for workers but also enabled the company to continue improving productivity.
The union has a $200 million strike fund, Duray said.
Houston-based Maxxam Inc., which is controlled by Texas financier Charles Hurwitz, owns 63 percent of Kaiser, the nation's fifth-largest aluminum company.
Written by Mark Jewell