HOUSTON — Like thousands of other Americans who have served in Iraq since the U.S. intervention began four years ago, Walter Zbryski came home in a coffin. Only his coffin was not draped in an American flag or accompanied by a military honor guard.

Instead, the mangled body of the 56-year-old retired firefighter from New York City was shipped back to his family in June 2004 in the bloodied clothes in which he died, with half of his head blown away, according to Zbryski's brother Richard.

"I viewed the body," Richard Zbryski said. "What really upset me was that he was laying there floating in at least 6 inches of his own body fluids. They didn't even clean him up for us."

Zbryski's death was not counted among the official tally of more than 3,200 American military personnel who have been killed in Iraq, nor was it noted by the Defense Department in a news release. That's because Zbryski was not a soldier — he was a truck driver working in the private army of hundreds of thousands of contractors hired by the Pentagon to support the logistical side of the massive American war effort in Iraq.

More than 770 civilian contractors working for American companies have died in Iraq since the U.S.-led invasion began on March 20, 2003, according to an obscure office inside the U.S. Department of Labor, which loosely tracks the figures. If those deaths — of truck drivers and cooks, laundry workers and security guards — are added to the military toll, the human cost of the U.S. war effort in Iraq is nearly 25 percent higher.

Now the family members of some of those American workers killed and injured in Iraq are raising their voices, complaining that the contributions of their loved ones have been forgotten by the U.S. public. Some allege that the workers were put in harm's way without adequate protection. Others charge that their own financial and psychological hardships have been ignored by the contracting companies that promised to help them.

"I think these deaths are glossed over and swept under the carpet," said Hollie Hulett, whose husband, Stephen, 48, was killed in an ambush in Iraq on April 9, 2004, while driving a truck for KBR, formerly Kellogg, Brown & Root, a subsidiary of oil services giant Halliburton. "I don't think anybody, including the Pentagon and the companies that hire these contractors, want it to be known that it is that dangerous over there and they are sending them out into a mess."

Critics of the war, and some members of Congress, have begun pressing the Bush administration to disclose more details about the Pentagon's reliance on private contractors to pursue the wars in Iraq and Afghanistan.

"We want to know how many contractors and subcontractors there are, the total cost of the contracts, the number of dead and wounded contractors," said Rep. Jan Schakowsky, D-Ill., who has introduced a bill to require the Bush administration to collect and publicize such information. "This is basic information. ... When you don't even count (the contractor deaths), you mask the cost in life of this war."

The most common estimate of the number of contractors working for U.S. firms in Iraq is 100,000, according to military analysts, but that figure includes unknown proportions of Americans, Iraqis and citizens of other countries.

The most recent statistic for deaths among those contractors is 770 as of the end of 2006, according to the Longshore and Harbor Workers' Compensation Division of the U.S. Labor Department.

But those figures, which also count 7,761 contract workers wounded in Iraq, appear to understate the casualties because they do not include killings of off-duty workers. Nor do they specify the nationalities of the victims.

The war zone jobs come with health and other benefits and are high-paying — contract workers in Iraq can earn $80,000 or more, most of it tax-free — and KBR has more than 500,000 applications from interested workers. But company officials insist that they provide repeated and explicit warnings about the dangers in Iraq to every job applicant during an extensive orientation program in Houston.

When employees are injured or killed in Iraq, officials at Halliburton headquarters say they are committed to helping the workers and their families.

But former KBR workers and their families say they got little help.

"It was like pulling teeth trying to find out from KBR what happened to Steve," said Hulett, whose husband was among six KBR employees killed when their convoy was ambushed along a route where fighting between Iraqi insurgents and U.S. forces had been raging for several days. "Later on, I asked KBR to continue paying my health insurance — I couldn't afford the COBRA for it, almost $800 per month. They refused. They wouldn't help."