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Sgt. Dan Thornhill was on patrol in a Humvee in Afghanistan on May 31, 2008, when his vehicle was hit by a car bomber carrying an improvised explosive device, or IED. The explosion ruptured the fuel tanks on the Humvee, fire engulfed the vehicle and two of his colleagues died. Sgt Thornhill suffered severe burns and lost both legs.

Fox News met Sgt. Thornhill at the U.S. Army's Burn Center at Brooke Army Medical Center in San Antonio Texas. He was airlifted there three days after the attack and, apart from a short time at another military hospital, has been there ever since. He has little memory of the attack itself.

"A lot of it is hindsight to me because a lot of it I don't remember," Sgt Thornhill said. "Your body has a way of shutting down. From what I was told a car bomb struck my truck. My left arm and my left shoulder suffered severe second-degree, third-degree burns."

On Aug, 3, 2008, a Fox News crew led by Fox News military analyst Colonel Oliver North was in a convoy that was hit by an IED. The Humvee containing cameraman Chris Jackson was rocked by the explosion, the fuel tanks again ruptured and fire again engulfed the Humvee. Chris Jackson was later honored by the Army for returning to the burning vehicle to save one of the injured soldiers who had been unable to get out.

IED attacks and the fires that often result from them are a nightmare scenario that many soldiers and marines have experienced. And it continues to happen as insurgents in Iraq and Afghanistan attack American patrols, their IEDs frequently targeting and breaching the fuel tank, causing devastating fires. Insurgents are now reportedly adding accelerants to the top of IEDs to increase the chances of fire.

Soldiers who have served in those wars said again and again that the Humvee, despite all the extra armoring added by the Pentagon, remains the most vulnerable vehicle they use. One soldier said the fuel tank is the weakest link of that vehicle and that the enemy is very well aware of that.

"Our greatest fear is getting burned alive," another soldier said.

The Pentagon has added fire suppression technology to the Humvee's crew compartment and to the engine compartment, but it has not added fire suppression technology for the fuel tanks, the most combustible part of any vehicle.

And yet, the technology is available to protect the fuel tanks on the roughly 13,000 Humvees currently being used for patrols in Iraq and Afghanistan. Two companies in the U.S. make plastic panels, weighing less than 30 pounds in total, that can be attached to the Humvee fuel tank in less than an hour. Those panels are filled with a fire suppressing powder that is released when the panels are shattered by a blast and instantly extinguishes any fire.

Fox News has seen video from an Army test of the fire panels in which an unprotected fuel tank bursts into flames when struck by a rocket propelled grenade. The same test on a fuel tank with the fire panels attached results in no fire.

The Army has also tested the technology on a Humvee itself, although that video is classified. The test happened on Feb. 1, 2006, and Fox News has learned that two days later an Army test engineer wrote in an e-mail to a Marine colleague who had inquired about the test, "Fuel tank and powder panel were penetrated several times and there was no resulting fire."

But nearly three years later, those panels, which cost roughly $2,000 per vehicle, have not been fitted to a single Humvee in either Iraq or Afghanistan. That's despite a formal request in the form of what the Pentagon calls an operational needs statement from then Lt Gen. Ray Odierno in Iraq in August 2007 calling for all vehicles to be fully equipped with fire suppression technology for all areas, including fuel tanks.

Pentagon officials say the plastic fire panels have cracking problems underneath the low-slung Humvee, a problem one of the manufacturers acknowledges but claims was fixed in 2007. The Army admits that there is always a trade-off in choosing how best to protect a vehicle given the weight and power constraints, but officials say the improvements they have made to Humvees offer the best solutions.

"The fuel tanks on the Humvee are not exposed," Gen. Ross Thompson said. "They're underneath the vehicle. They're behind armor protection, and so the most comprehensive thing we can do is protect the crew compartment and to provide the armor protection on the sides to keep the fuel tank from being hit."

Fox News Military Analyst Major Gen. Bob Scales agrees with what the Army has done.

"It's a judgment call and I think the Army made the right call," he said.

North is less convinced.

"If the Army thinks the up-armored Humvees are the answer, they've got the wrong question," he said.

Republican Rep. Joe Wilson also wants more answers. He first wrote to the secretary of the Army in December 2008 about fire suppression technologies.

"There appears to be a lack of significant urgency in providing soldiers a solution that will save lives," Wilson wrote. His concerns, he says, remain. "We can save lives, we can avoid maiming people for life. It's just so easy to do. It can be added to vehicles in a matter of hours, the cost is 2-3 thousand dollars. Minimal costs."

Burn injuries cost lives and millions of dollars. More than 800 U.S. troops have suffered severe burn injuries in Iraq and Afghanistan since 2003, and an independent study by burns specialist Dr.Ruth Rimmer at the renowned Arizona Burn Center estimates that lifetime care for every one of those burn victims easily runs into millions of dollars.

"Anywhere from hundreds of thousands to millions of dollars worth of care which is required for the rest of their life," Rimmer said.

Rimmer's estimate is backed by Col. Evan Renz of the Burn Center at Brooke Army Medical Center in San Antonio, where every severely burned American serviceman or woman is sent first. And Col. Renz also pointed out the added cost of getting the soldier out of the war zone.

"You add the (evacuation) costs and you add the long term costs -- it's a huge figure," Renz said.

Sgt Thornhill, in the meantime, has many hours of surgery ahead of him and probably a lifetime of pain. Might those fuel tank fire panels have lessened his injuries? He'll never know.