Choir practice normally started at 7:20 p.m. at the West Side Baptist Church in Beatrice, Neb. But on March 1, 1950, all 15 members were late.

One pair of sisters had car trouble; they called for a ride from a third member, who was delayed by homework. A mother and daughter were detained at a relative’s house. The choir director was late because her daughter, the pianist, had fallen asleep. Other members needed to finish a letter or hear the end of a radio program. One was “just plain lazy.”

So no one was there at 7:25 when the building exploded. The blast shattered local windows and forced a nearby radio station off the air.

The church furnace, it seems, had ignited a gas leak.