Striking workers shut down the largest terminal at the Port of Los Angeles for a second day Wednesday, and the job action later widened to close three terminals at the Port of Long Beach, threatening to paralyze the nation's busiest port complex.

About 70 clerical workers struck the APM Terminals operations on Pier 400 at Port of Los Angeles on Tuesday, raising the ante in a 2½-year-old contract battle over union claims that management has been outsourcing well-paid jobs out of state and overseas.