Three government investigations are focusing new attention on combat body armor more than a year after a Pentagon study concluded the extra armor, available since 2003, could have spared the lives of up to 80 percent of Marines who died of upper-body wounds in Iraq.

One investigation, most of which remains classified, has been completed and two more are due in the second half of the year. All of them seek to answer persistent questions from members of Congress about the quality and quantity of equipment available to Marines, soldiers and other service members in Iraq.

Meanwhile, the Marine Corps is touting the arrival in February of an updated version of its body armor vest.

Capt. Jeffrey Landis, a spokesman for Marine Corps Systems Command in Quantico, Va., said the full order of 60,000 new vests is expected to reach Iraq by September. The vests are being manufactured by a Florida company under a $38 million contract.

The vests, which weigh about the same as the earlier version, are intended as a stopgap until lighter, better-fitting, more protective gear under development is perfected in the next three to five years, Landis said.

Improvements in the vest reaching Marines this year will make it more comfortable and able to carry such items as water, grenades and ammunition magazines into combat, according to an announcement in November from systems command, the Marines' main agency for buying and maintaining military equipment.

The earlier vest is not designed to carry such items on combat missions. The announcement also cited changes designed to make the vest easier to remove in emergencies, such as vehicle rollovers or emergencies involving deep water.

One of the vest's major changes is a single-unit design in which a protective plate is now incorporated into the vest. The older design requires wearers to hang the plate on the outside of the vest. The old design sometimes interfered with arm movement, Landis said.

The improvements were made in response to comments solicited from Iraq war veterans at Camp Pendleton and elsewhere in December 2005, according to systems command.

"If a Marine is more comfortable wearing the gear than what he is wearing now, he is more combat-effective," Landis said.

The vest redistributes weight from the back to the front of the torso, a change that earned praise from 1st Lt. Mauro Mujica, a weapons platoon commander with the 3rd Battalion, 7th Marines at Twentynine Palms.

"It is common for a Marine to wear a loaded vest for many hours in a harsh environment. The cummerbund design really makes the vest feel lighter and more comfortable because the weight is better distributed throughout the body," Mujica said in a statement provided by systems command. "This added comfort will help us be faster and more agile during combat situations while affording us a maximum amount of protection from various enemy threats."

The new armor is arriving as the Pentagon's inspector general is investigating body armor contracts, an investigation being done at the request of Rep. Louise Slaughter, D-N.Y.

John Santore, a spokesman for Slaughter, said she made the request in response to a New York Times story disclosing a secret Pentagon report that said more extensive shielding could have saved up to 80 percent of Marines who died of upper body wounds during the first two years of the Iraq conflict.

The inspector general's investigation is scheduled to be completed in October, according to a letter from the inspector general's office posted Thursday on Slaughter's Web site. The letter, dated Jan. 30, states that Slaughter was especially interested in whether the Defense Department "followed proper procedures for the procurement of the equipment."

At Slaughter's request, the inspector general has launched a similar investigation into procurement practices for armored vehicles. That report is due to be completed in July.

Slaughter and other congressional Democrats have seized on doubts about the effectiveness and availability of body armor as an example of the failure of Republicans to investigate how well defense contractors were fulfilling their obligations.

"I think it's deeply troubling to Rep. Slaughter and members of the Democratic leadership that Republicans failed to carry out their oversight duty and failed to examine which contracts were going to which companies," Santore said.

Josh Holly, a spokesman for Rep. Duncan Hunter, R-El Cajon, the ranking Republican on the House Armed Services Committee, said Hunter has pushed Army and Marine officials to quickly deploy advanced body and vehicular armor for soldiers and Marines. He has also constantly asked military leaders about what they need to protect troops in combat, Holly said.

Another report from the Defense Department's inspector general, completed in January, said some troops in Iraq "were not always equipped to effectively complete their missions."

Most of the report, except for a three-page executive summary, remains classified.

Maj. Raymond Kimball, a military historian at the Army's West Point academy and a member of Iraq and Afghanistan Veterans of America -- an advocacy group for combat service members -- said Thursday that he was amazed at what the executive summary revealed.

"It's hard to believe that the same country that 60 years ago was the arsenal of democracy is still struggling to get mission-essential equipment to soldiers in a timely manner," Kimball said.

Santore said that body armor was a not a major part of the January report, but called it a valuable first step in what he said will be a series of audits and House oversight investigations into body armor and other equipment-related problems.

"It's just setting the stage and giving a broad overview," he said.

Marine officials have insisted in published reports that they have done all they can with existing body armor to prevent death and serious injury to those combat.

Landis said the design and use of body armor required military leaders to strike a balance between protecting the wearers and providing Marines with enough mobility, agility and comfort to perform their missions.

"The only thing I can say is that this is the best protection available to our forces. It has been proven to save lives," Landis said.

He said the earlier version of the vest had saved "countless lives" in battle, and that three weeks of field tests involving forced marches, maneuvers through urbanized terrain and emergency exit drills, showed the new version will be even more effective.

- William Finn Bennett contributed to this story. Contact staff writer Joe Beck at (760) 740-3516 or jbeck@nctimes.com.