OKLAHOMA CITY — After a huge tornado ripped through the Oklahoma City suburbs this spring and demolished two elementary schools, killing seven children, a longtime legislator thought the time was ripe for the state to act on a well-known problem.

Although Oklahoma averages more than 50 tornadoes a year, and sometimes gets more than 100, about 60 percent of public schools have no shelters. Cash-strapped districts in the state can’t afford to build them.