While on missions in Iraq last year, 35-year-old Todd Drobnick was attacked by small-arms fire, grenades and makeshift bombs. Yet he continued to go out day after day, until he died in a vehicle crash on his way from one U.S. military base to another. For his loyalty and dedication, he was posthumously awarded a Purple Heart and Bronze Star.

Thousands of Americans in Iraq have received such honors, but Drobnick's case was unusual: He wasn't a soldier. He was a private contractor working with a translation company.

"He died in the service of his country and the gratitude of his comrades is deep and lasting," U.S. Army Col. Gary L. Parrish, assistant chief of staff of intelligence, wrote in a letter to Drobnick's family after his death.

Several other contractors have received battlefield commendations in Iraq, too, but the military says it was a mistake. Only active-duty soldiers are eligible for the awards and those received by civilians are being rescinded.

"This is not to say that what the contractors did wasn't valorous or wasn't important, but legally we aren't supposed to give them these awards," said Shari Lawrence, an Army spokeswoman.

The confusion demonstrates that in many situations soldiers and civilian contractors have become virtually indistinguishable -- and interchangeable -- in postwar Iraq.

The occupation could not function without contractors. Construction giants such as Bechtel Inc., Fluor Corp., Parsons Corp. and Perini Corp., are rebuilding the country's infrastructure. Blackwater Security Consulting and Erinys, staffed with former Special Forces fighters, provide security details for occupation personnel. General Dynamics Corp. and Halliburton Inc. subsidiary KBR supply the military with support personnel who handle such diverse duties as repairing tanks and cooking.

The estimated tens of thousand of contractors in Iraq -- who according to the Brookings Institute amount to more than 10 percent of U.S. personnel there -- have become a flashpoint for the troubles of the U.S.-led occupation.

First, there were accusations that lucrative contracts for the reconstruction of Iraq had been given to allies of the Bush administration. Then, after four security contactors were killed last month while escorting a U.S. military convoy, there were concerns about the lack of rules and regulations governing the private armies. Now, with allegations that contractors may have allowed or instructed soldiers to abuse detainees at the Abu Ghraib prison in Iraq, there are questions about their accountability in a place where laws are still being written.

"What we're seeing is the extreme result for this passion for outsourcing which ignores the fact that there are some things only government should do," said Danielle Brian, executive director of Project on Government Oversight, a watchdog group.

Private contractors have long served alongside soldiers in wars, but their duties used to be relatively mundane: cooking, supporting technology systems, transporting supplies. There has been a significant shift in recent years, however, in the duties the Pentagon has entrusted to contractors. Companies are now taking more responsibility for some of the military's most sensitive jobs -- providing technical trainers, security protection details, linguistics experts, and "intelligence services," a catchall term that includes everything involved in the gathering and analysis of data.

Fairfax's SRA International Inc., for example, provides scientists to help investigate biological and chemical weapons that Saddam Hussein's regime might have developed. Arlington's CACI International Inc. has a one-year contract to provide prison interrogators. San Diego's Titan Corp. -- Drobnick's employer -- supplies interpreters who are inseparable from soldiers who go out into Iraqi communities in their Humvees.

Pentagon officials have said using contractors saves money, allows the military to tap the private sector for skills it lacks and forces it to concentrate on its core mission of protecting the country. But the independence with which contractors operate is heightening concerns that the line between the military and its contractors has become too blurry and whether the military become too dependent on contractors it can't properly control.

Of particular concern to Congress has been where -- or if -- contractors fall in the military chain of command.

In a report summarizing an Army investigation into what happened at Abu Ghraib, Maj. Gen. Antonio M. Taguba concluded that a contractor for CACI International may have allowed or instructed soldiers to abuse prisoners. One translator for Titan Corp. was admonished for providing false statements to investigators and another was named as a suspect and witness. The military employs 27 CACI interrogators and hundreds of Titan translators in Iraq, according to congressional testimony by Lt. Gen. Lance L. Smith, deputy command of Central Command.

Four contract interrogators, six contract screeners -- who decide the level of "intelligence value" detainees might have -- and numerous contract translators were stationed at Abu Ghraib.

Contractors typically have no formal authority to manage military personnel and many consider themselves partners or advisers. In practice, however, soldiers say contractors may exert tremendous influence on the rank and file because of their technical expertise and because they are often brought in to work with high-level military officials. Their presence, some argue, has complicated what used to be a clear chain of command. Military contracts lay out the limits of contractors' duties and responsibilities in clear terms, officials say, but in the field their roles often change depending on their backgrounds and their relationships with soldiers.

During his four-month tour as a CACI interrogator at the Abu Ghraib prison, Torin S. Nelson said, he was mostly on his own. Besides his schedule, there was little oversight of how he did his job questioning Iraqi detainees and he often found himself advising less-experienced military colleagues.

"Civilian interrogators were often free to conduct operations as they best saw fit," Nelson, who is named as a witness in the Army investigation, said in an e-mail response to questions. (Nelson was mistakenly identified as a Titan employee in the report, he said.)

That contradicts testimony this week from Stephen A. Cambone, the Pentagon official responsible for intelligence, that contract interrogators worked "under the supervision of military personnel."

Yet, Cambone also noted, "there may have been circumstances under which this regulation was not followed." He said the issue is under investigation.

Rep. Janice D. Schakowsky (D-Ill.) last week asked President Bush to suspend the prison contracts until investigations are complete. She said she worries that contractors have divided loyalties. "Are they taking orders from their CEOs and shareholders and then telling our soldiers what to do?"

Sen. John McCain (R-Ariz.) said: "I'd like to know who was in charge . . . what agencies or private contractors were in charge of interrogations. Did they have authority over the guards? And what were their instructions to the guards?"

Contractors are not subject to military codes of conduct and not held to the same rules as government workers, including the Geneva Convention that protects human rights, defense analysts say. The Coalition Provisional Authority exempted contractors working for the occupation from Iraqi law; instead they are to follow the laws of their own countries and could be charged and tried at home for violations. Cambone testified that contractors are "subject to suspension from their contracts by the government for cause. Criminal sanctions may be pursued by federal authorities.

CACI chief executive J.P. "Jack" London has declined to discuss his employees' work at the prison but said the company is very selective in hiring interrogators, sending only 3 percent of the 1,600 applications to the military for approval. Most of the applicants had military training in interrogation and all of them had security clearances, London said.

In Iraq, the contract interrogators worked in three-person teams with a translator and an analyst. They answered to CACI managers, London said, and did not participate in the military chain of command.

The bureaucracy of the contracting process also complicates how contractor operations are run because it's unclear who the client is. For example, the request for contract interrogation support originally came from Command Joint Task Force 7, the military group that oversees coalition forces in Iraq. It was then sent to the Interior Department and processed at a federal business center at Fort Huachuca, Ariz. The Defense Department will pay for CACI's interrogation services.

Contract translators also are being investigated for their roles in abuses at Abu Ghraib and other facilities -- including one in which a detainee being questioned by the CIA died. The military is almost entirely dependent on contractors, and specifically on Titan, for Arabic interpreters.

Titan, which has a contract worth up to $657 million, employs 4,200 people worldwide who work with the military. The majority are assigned to Iraq, Kuwait, Qatar and Afghanistan, according to the U.S. Army Intelligence and Security Command.

More than a few of the interpreters are doctors, artists, grocery baggers, recent college graduates and others with no background in translating, according to interpreters and military officers in Iraq. Titan spokesman Wil Williams said interpreters hired in the United States and Iraq must pass oral and written exams demonstrating their fluency in Arabic and English, Williams said. The translators also go through a one-week program at Fort Benning, Ga., on how to work with the military, how to protect themselves and even on the Geneva Convention, he said. The Pentagon conducts a counterintelligence check on Iraqi translators to ensure that they are not former members of the Baath Party or should not be hired for other reasons.

"Titan does not send any linguist into Iraq that is not fully qualified in the language or dialectic the military is searching for," Williams said. "Just because an applicant may be a doctor or a businessman or have some other vocation doesn't mean he is or she isn't qualified to speak fluent English and Arabic and support the military."

The Army intelligence command said in a written response that Titan translators are hired only to do "verbatim" translation. In Iraq, however, many military officials depend on them for advice about the culture and it's not unusual for them to sit in on high-level strategy meetings at the battalion or brigade level, or even to help plan convoy routes and raids, according to interpreters and military officers in Iraq.

The push to expand the role of private companies in the armed forces began in earnest in 1999, the height of the dot-com boom, when it seemed that private industry's fast-paced innovation could move the military to the next level of warfare. Until then, defense contractors played mostly supporting roles. They worked as systems integrators, stitching together the various antiquated computer systems, and providing technical assistance. They also did menial labor at bases.

Retired Maj. Gen. Edward B. Atkeson, who was deputy chief of staff of intelligence for the Army's European operations, was part of a group of two- and three-star generals invited in 1999 to participate in a panel to discuss the future of military contracting. He said many agreed that it made sense to hire civilian contractors to take over training operations such as teaching soldiers how to drive certain vehicles and the writing of manuals. It also seemed equally clear that the power to order someone to pull the trigger and bomb a target should stay with the military.

But, Atkeson said, there was debate and disagreement about nearly every task in between. "I'm not sure there's a line," he said. "It's at the edge of a cloud and we've been fading into it and we're still trying to determine how far we want to go."

Civilian contracting accelerated after the Sept. 11, 2001, attacks on the World Trade Center and the Pentagon, when it became clear that the government lacked the language skills it needed to penetrate terrorist networks, according to congressional testimony. The result has been that in the sea of camouflage that represents the U.S.-led occupation in Iraq, it's often impossible to tell the soldiers from private contractors and to determine who is in charge.

Military police ride shotgun for KBR drivers who deliver supplies to bases. Armed guards from Blackwater shoot from rooftops to protect bases from attackers and also guard L. Paul Bremer, the occupation's civil administrator. Army officers work alongside contractors to rebuild schools and set up local councils.

At first glance, the only sign that differentiates contractors from soldiers is that instead of their last name emblazoned on the left breast pocket of the uniforms they wear, it says "US CONTRACTOR" or "DOD CIVILIAN."

Of course, private industry employees can earn salaries in the $100,000s and take paid leaves every six weeks and have hotel-like accommodations. Soldiers earn much less, work a year or longer without a break and must rest in sleeping bags in common areas that accommodate dozens.

But the work, soldiers and contractors both say, is often interchangeable.

As director of the Baghdad Police Academy, Mel Goudie, an official with the Coalition Provisional Authority that rules Iraq, supervised a training team that included military police and contractors. In Iraq's reconstruction, Goudie said soon after he took his job last fall, "the military role and the civilian-contractor role are exactly the same."

Staff writer Ellen McCarthy and researcher Richard Drezen contributed to this report.

Former hostage Thomas Hamill, center, was a truck driver in Iraq and worked for KBR, a Halliburton subsidiary.Civilian security personnel hired by Blackwater were under attack April 4 in Najaf. Contractors now do many of the jobs once reserved for soldiers.