Federal investigators’ preliminary report on the August 2nd explosion at Minnehaha Academy finds a school maintenance worker heard and smelled the natural gas release, went to the basement meter room that workers had evacuated because of a leak, then made an announcement over his hand-held radio to evacuate the building and searched for occupants. Less than a minute later, the building exploded. The National Transportation Safety Board report does not say whether the radio transmission contributed to the blast. Workers were in process of moving gas meters from the basement to the outside. Two people died in the explosion.