Eight other servicemen were also injured when the powerful 60 mm mortar exploded at the Hawthorne Army Depot Monday.
Officials identified those who were killed as:
- Pfc. Joshua M. Martino, 19, of Clearfield, Pa.
- Lance Cpl. David P. Fenn II, 20, of Polk City, Fla.
- Lance Cpl. Roger W. Muchnick Jr., 23, of Fairfield, Conn.
- Lance Cpl. Joshua C. Taylor, 21, of Marietta, Ohio
- Lance Cpl. Mason J. Vanderwork, 21, of Hickory, N.C.
- Lance Cpl. William T. Wild IV, 21, of Anne Arundel, Md.
- Cpl. Aaron J. Ripperda, 26, of Madison, Ill.
Five of the seven killed joined the Marines in June 2010, with Wild a Marine since October 2010 and Ripperda since September 2008. The 26-year-old was scheduled to come home in May. Martino and Taylor were both engaged to marry their fiancees later this year.
Hundreds of Hawthorne residents turned out to mourn the fallen Marines, all from the 2nd Marine Expeditionary Force in Camp Lejeune, N.C., at a brief memorial service Tuesday.
"The evening of March 18, 2013, will forever be remembered as a moment of profound tragedy in Mineral County," District Attorney Sean Rowe told the memorial service. "You have given meaning to the phrase, 'America's Patriotic Home.'"
The accident has prompted the Pentagon to restruct the use of the mortar shells until an investigation can determine their safety.
ABC News and The Associated Press contributed to this report.