HILO, Hawai'i — The family of a soldier who was killed in 2006 when a mortar round exploded prematurely in a mortar tube at Pohakuloa Training Area has sued the manufacturer of the weapon.

Staff Sgt. Oscar Rodriguez, 27, was killed on March 10, 2006, while supervising a training detail that was firing two 81mm mortars at a PTA artillery range when the shell exploded in the tube.

The blast launched shrapnel that killed Rodriguez, who was stationed at PTA. Also injured in the blast were Sgt. Samuel Oyola-Perez, Pvt. Julius Riggins and another soldier Wilfredo Dayandant, according to the lawsuit.

The lawsuit was filed Friday in Hilo Circuit Court by Rodriguez's wife Stephanie Rodriguez, a Missouri resident. Stephanie is also mother of Rodriguez's son, Jacob, who was 5 months old at the time his father was killed.

Joining in the suit are Hawaii residents Oyola-Perez and Dayandant, and California resident Riggins.

The suit alleges the shell manufactured by Martin Marietta Aluminum Sales Inc. was defective and "unreasonably dangerous" because it failed to meet industry and company standards, and was not properly inspected .

The case was filed against Commonwealth Aluminum Sales Corporation, formerly known as Martin Marietta.

Also named in the suit are Lockheed Martin Corp. of Maryland and Alexis International Inc. of Ohio, which the suit alleged have acquired the liabilities of Martin Marietta through merger and acquisition.

Oscar Rodriguez's mother Janie Edwards said after the accident that U.S. Army officials told her the mortar round explosion before the projectile was launched was a "one-in-a-million" weapon malfunction.

Rodriguez, an Iraq war veteran, was knocked down by the blast, and apparently did not realize he had been hit until it was too late. He died of blood loss and a collapsed lung.

Edwards said at the time that Army representatives told her another soldier suffered severe arm injuries in the blast, and a third soldier lost an eye. Two other soldiers suffered other injuries, she said.

Rodriguez, Beeville, Texas, native, was assigned to the 25th Infantry Division's 1st Battalion, 14th Infantry "Golden Dragons," and died a day before his 28th birthday.

He joined the Army in 1996, and served in Iraq for 13 months before being assigned to Hawai'i. He wanted to be a drill sergeant and planned to make a career out of the Army, his mother said at the time.

Reach Kevin Dayton at kdayton@honoluluadvertiser.com.