On April 14 1955 a fully-armed, supersonic Nike-guided missile was accidentally fired over the Washington DC area.
Battery C of the 36th antiaircraft battalion, stationed at Fort Meade, Maryland (about 14 miles from the White House) was raising the rocket launcher at midday as a routine training exercise. The launcher was not fully upright when the booster rocket fired, sending the missile into the sky. The cause of the launch was a short circuit caused by rain getting into an electrical junction box.
The booster separated and fell on a nearby trailer park and fuel tank fragments spilled onto a nearby parkway. The missile's nose section was found 500 yards from the launcher with the guidance assembly still attached.
A military historian wrote that “Because no launch was intended, the pin of the launcher's forward yoke support had not been removed. As the pin had not been removed, the yoke remained in place when the Ajax took off, tearing out the No. 3 Tunnel or fairing strip covering essential wiring on the missile's side. This damage rendered the missile warheads inoperative and prevented an explosion.”
The Army, which originally said the Nike Ajax missile exploded in the air, let several days pass before clarifying that the warhead did not detonate.