By Khari Johnson | CalMattersAbout 4,000 California Department of Public Health employees have been told they must use a federal verification system to prove they’re U.S. citizens. The department is also making the move to address incomplete employment eligibility records identified in a recent audit, according to the Service Employees Union International Local 1000, which represents roughly 3,000 department employees. As at other U.S. employers, all new California health department employees complete a federal I-9 form to prove their citizenship. Walls told CalMatters the health agency is currently the only California state department the union is aware of that has asked their employees to recertify their citizenship status. The union represents about 100,000 state employees at 140 state agencies, boards, commissions and departments.