An 81 mm mortar round that misfired in 2006, killing a 27-year-old Schofield Barracks soldier at the Big Island’s Pohakuloa Training Area, was not defective, a jury in a federal civil trial determined yesterday.

The verdict frees the manufacturer from liability.

Staff Sgt. Oscar Rodriguez died March 10, 2006, when a mortar round exploded in the mortar tube. Another soldier, Wilfredo Dayandante, died several years later of injuries suffered in the blast, the lawsuit claimed.

Two other soldiers were injured.

Rodriguez’s wife, Stephanie; Dayandante; and the two injured soldiers, Samuel Oyola-Perez and Julius Riggins, sued General Dynamics Armament and Technical Products Inc., claiming the mortar round exploded prematurely because of a manufacturing defect. General Dynamics owns the company that assembled the mortar round.

Dayandante died May 19, 2009.

General Dynamics said operator error caused the accident.

Company lawyer James Yukevich said that according to trial testimony, the explosion happened after the mortar crew loaded a second round into the tube. The first round exploded, ejecting the second round, he said.

He also said there was evidence that suggests the firing pin at the bottom of the tube was loose. That might explain why the first round did not fire after it was dropped into the tube.

An Army investigator said the mortar crew loaded the first round into the tube, did not notice that it did not launch, went on break, then loaded the second round after the break.

General Dynamics Armament and Technical Products issued a statement yesterday that it had offered $5.1 million to settle all claims and that the plaintiffs sought $29 million in damages.