HONOLULU (AP) - The Army says a Makua Valley explosion that injured two contractors in April was caused by an anti-tank weapon round.
U.S. Army Hawaii Public Affairs said in a story posted in an official Army publication on Friday that investigators determined the round was fired from a weapon used at Makua until the 1980s.
The Hawaii Army Weekly story says investigators weren't able to determine when the round was fired. They don't know what unit or organization fired it.
The ordnance was a 66 mm High-Explosive Anti-Tank round. It was fired from a M72 Series Light Anti-Tank Weapon.
The contractors were cutting grass and maintaining the grounds of the Oahu training range when the explosion occurred.
The Army plans to reopen Makua after implementing mitigation measures to prevent a similar incident.