Teachers at a charter network in Chicago have voted to take the first step toward the country’s first charter-school strike.

Earlier this week, 503 of the Chicago Teachers Union’s 536 members at Acero’s 15 charter schools voted to authorize a strike. (Most unionized members turned out to vote.) They are fighting for pay raises, smaller class sizes, increased special education staffing, and extended parental leave.

Teachers at four more unionized charter schools in the city—part of the Chicago International Charter Schools network—will vote on whether to authorize their own strike tomorrow. (Update, 11/2: Nearly all of the union members at those four schools voted to authorize a strike. They could now strike for pay raises if bargaining fails.)

Source: Is the Nation’s First Charter School Strike Imminent? – Teacher Beat – Education Week