SSG Roy Phillips and SP4 Daniel E. Helton were killed on 12 March 1973. SSG Phillips and SP4 Helton were assigned to the 58th Ordnance Detachment (Eplosive Ordnance Disposal). They were setting up a demolition shot on the demolition range at Fort Irwin, California. The demolition shot prematurely exploded killing SSG Phillips and SP4 Helton, and injuring a civilian observer. The unit had been experiencing problems with sniper fire on the range and it is suspected that sniper fire initiated the explosion.