MORE than 50,000 Los Angeles county workers have walked out after talks on a new contract broke down, closing libraries and disrupting administrative operations.

The two-day strike began on Monday evening after the failure of negotiations on a new contract to replace the one that expired in March, according to leaders of the Service Employees International Union’s “local” (branch) 721.

The branch, which represents more than 55,000 workers, including in public health, social work, parks and leisure services and clerical functions, says it is first time all of its members have gone on strike. With 10 million residents, Los Angeles is the most populous county in the United States.