Some 175 educators launched a strike Tuesday at four campuses of the Chicago International Charter School — the second charter network to strike in the city this school year.

Teachers hit the picket line at 6 a.m. Tuesday outside CICS’ ChicagoQuest, Northtown, Wrightwood and Ralph Ellison schools.

The workers want better pay, smaller class sizes and additional social workers and school counselors to be hired.

“They are pocketing increased taxpayer funding and insulting our teachers and low-wage paraprofessionals with threats to cut counselors, social workers and critical frontline programs for our overwhelmingly low-income students” CTU Vice President Stacy Davis Gates said.

Civitas Education Partners, which manages the schools, lamented a compromise couldn’t be reached after 30 bargaining sessions over nine months. They said teachers were offered 28 percent raises over four years, more paid time off and other concessions.

“CICS is deeply disappointed that the Chicago Teachers Union has chosen to strike at four CICS campuses,” the school said in a statement. “This strike will place a significant burden on the families of the four schools, reduce 2,200 students’ access to learning and it will cause long-term harm to the school community at our four campuses.”

The union slammed the charter operator for vowing to stay open, accusing them of lining up “scabs” from a for-profit substitute teacher company to cross picket lines.

Civitas officials say they’d keep “enough adults in the building to ensure that students are safe,” with principals and non-union staff still on the job and students participating in “online learning, recreational and arts activities.”

“Our first responsibility is the safety and well-being of each of the 2,200 students who attend our four schools,” Civitas CEO Leeandra Khan said in a statement.

CTU officials accuse the charter operator of hoarding $36 million in public funds, a nest egg that management says is a necessary emergency fund equivalent to three months of operating expenses.

“We know that CICS has the money and the ability to do better by our students and schools,” Jen Conant, a CICS Northtown math teacher who chairs the teachers’ bargaining team, said last month when the union announced a strike date.

The starting salary for a CICS teacher is about $44,000, about $8,000 less than starting Chicago Public Schools teachers make.

The CICS teacher walkout is Chicago’s second-ever charter teacher strike, following Acero network educators who hit the picket line for four days in December to win 2 percent yearly cost-of-living pay increases, along with provisions to reduce class sizes and prevent the network from sharing information on undocumented students with immigration authorities.