Some 12,000 9-1-1 dispatchers, social workers, health and hospital workers, nurses, park workers, janitors, clerks and roads and maintenance workers — among others — represented by Service Employees International Union Local 521 plan to go on strike Friday unless the Santa Clara Board of Supervisors intervenes, the union said in a statement Sunday.

“The county is proposing eliminating the wage increase for June 2020 that they included in their ‘last, best and final’ offer of 2019,” said Janet Diaz, a patient services clerk at Valley Medical Center, in Sunday’s statement. “This is not only illegal, but a deliberate attack on the livelihoods of