COLUMBUS, Ohio — Columbus Education Association members will see an 8% increase in health insurance premiums after the union’s joint insurance committee approved plan changes last week, as the union presses the school board to account for a roughly $40 million health-care cost overrun. More than 100 people attended Tuesday’s Columbus City Schools board meeting to raise concerns. The CEA, which represents thousands of district teachers and staff, has said the district is facing a financial crisis and criticized the board’s leadership, transparency and governance. The union’s legislative assembly voted no confidence in the school board last week. CEA spokesperson Regina Fuentes said the union wants board members to acknowledge their responsibility and explain the $40 million difference between projected and actual costs. “We would like the board of education to openly be transparent about their role in this $40 million loss,” Fuentes said, adding that the district should establish safeguards to prevent a similar situation. Board President Antoinette Miranda disputed the characterization of the money as lost. She said the costs covered employees’ medical benefits, including doctor and hospital visits, and pointed to rising health-care expenses as a factor in the higher-than-expected spending. The union’s concerns include what it describes as the board’s failure to act to recover allegedly misspent funds, as well as a demand that the board publicly recognize its role in the health-care crisis. The available information does not establish that funds were misspent; Miranda said the money paid for employee care. Fuentes said teachers understand insurance costs are rising nationally but object to employees bearing the added expense. Miranda said premiums and costs are increasing and credited the district’s consultant, AON, with helping avoid even larger premium hikes and additional plan changes. District employees’ open enrollment began Monday, putting the plan changes and premium increase directly before staff as the union’s dispute with the board continues.