None of South Dakota's school districts has trained sentinels 10 months after a law allowing for it took effect.
State legislators passed the law in March 2013, a few months after the deadly Sandy Hook Elementary School shooting.
At least 33 states presented bill to authorize arming teachers or administrators, the National Conference of State Legislatures says. South Dakota is one of nine states that passed such a law.
Rep. Betty Olson co-sponsored the measure and says districts haven't used the policy because there hasn't been a school shooting recently. School administrators say they have not established a sentinel program because they don't see the need for a contentious policy.