California schools are on the hook for $24 billion in future health care costs for their retirees, a mountain of debt that’s forcing some districts to curb benefits or spend less on teacher salaries and classroom equipment, according to a new state report. Los Angeles Unified School District boasts a whopping 56 percent share — or $13.5 billion — of the unfunded liability, although it educates nine percent of California’s public school population. It’s historically provided some of the most generous retiree health benefits, including lifetime coverage for retirees and their spouses. Teachers’ union representatives argued good health care is an essential tool for recruiting and retaining teachers. But the looming debt means newer teachers are offered skimpier benefits and less money is available to spend in classrooms.