The Richmond, Indiana explosion was a double explosion which occurred at 1:47 PM EST on Saturday, April 6, 1968 in downtown Richmond, Indiana. The explosions killed 41 people and injured more than 150. The primary explosion was due to natural gas leaking from one or more faulty transmission lines under the Marting Arms sporting goods store, located at the intersection of 6th and Main streets. A secondary explosion was caused by gunpowder stored inside the building.
Twenty buildings in and adjacent to the site of the explosion were condemned as a direct result of the explosions. Ultimately, the main street through downtown Richmond was permanently closed to traffic and the Downtown Promenade was built in 1972 (later expanded in 1978). This five-block pedestrian mall was converted to allow the street to be reopened to traffic 29 years after the explosion, in 1997, as part of an urban revitalization effort.
A simple curved brick memorial honoring those lost in the tragedy was erected in the downtown, with metal lettering: In memory of the forty-one persons who lost their lives in the tragic downtown explosion April 6, 1968 and with everlasting gratitude to those who helped give rebirth to this city.