WASHINGTON - The 130,000 American troops serving in Iraq are more likely to die in accidents, from natural causes, or in other "nonhostile" incidents than at the hands of insurgents, according to Defense Department statistics for the past eight months ending in April.

A US soldier of Bravo Company, 1-18 Infantry Battalion stands guard during a patrol at a market in Mosul, 390 km (242 miles) north of Baghdad, in this February 2, 2009 file photo. (REUTERS/Erik de Castro) The statistics highlight the dramatic reduction of violence in Iraq over the past year, but also underscore a challenge that has bedeviled US troops in Iraq and Afghanistan since hostilities began: A steady stream of soldiers and Marines are losing their lives in circumstances that are often preventable.

Between September 2008 and April 2009, 72 troops died in Iraq from accidents, illness, or suicide, compared with 67 who died in action, according to the Pentagon - the first extended period in the six-year conflict where insurgents did not pose the greatest threat.

In response to the growing number of deaths and injuries occurring outside combat - most of which are attributed to accidents - the Defense Department recently approved plans to hire hundreds of additional safety specialists to deploy with Army and Marine Corps units, according to top safety officials. The military has also initiated a series of new training drills such as a simulation exercise that teaches troops how to escape if their Humvee rolls over.

"We are taking them very seriously," Lieutenant Colonel Michael Miller, the top ground safety officer at Marine Corps headquarters, said of the nonhostile casualties. "Whether a Marine or soldier is injured or, God forbid, killed in some kind of accident, at the end of the day we have lost that person."

Miller and others said the deaths and injuries go "beyond the human aspect" and degrade the overall readiness of the force.

"As stressed as the Army force is, rotating soldiers in and out of a combat zone, the last thing we need" are casualties that can be prevented, said Sergeant Major Tod Glidewell, the senior noncommissioned officer at the Army Combat Readiness Center at Fort Rucker, Ala.

Some specialists, meanwhile, also expressed concern that an increase in accidental gunshot wounds and suicides may be new evidence of pressure on troops who have served multiple tours.

"That is a sign of wear on the force," said Paul Reickhoff, an Iraq veteran who is now president of Iraq and Afghanistan Veterans of America, a leading advocacy group. "It has become cumulative."

Officials say they have made strides in controlling some types of accidents, such as vehicle rollovers. But those declines have been offset by the increase in weapons accidents and suicides, meaning that the rate of deaths by nonhostile causes has remained fairly steady throughout the Iraq war - between 100 and 175 per year.

Compared with past conflicts, the percentage of nonhostile deaths is at a historic high. A full 20 percent - or 1 out of every 5 - of all US troop deaths in Iraq have been the result of nonhostile wounds. In Afghanistan - where far fewer US troops have been engaged in combat - the share of nonhostile deaths is nearly half of the total, although, with violence increasing, hostile deaths are on the increase.

While officials stressed that the casualty information is far more accurate and detailed today than it was in the past, in both cases those percentages are higher than in the Vietnam and Korean wars, according to historical Defense Department data.

Military officials began taking notice last summer that, even as overall violence in Iraq declined, nonhostile incidents continued unabated - and in some categories increased.

"Unfortunately, according to casualty and medical reports, noncombat injuries and illnesses are now the number one hazard in Iraq," an internal report by the Marine Corps Center for Lessons Learned concluded.

The biggest cause of nonhostile deaths remains accidents. Since the start of the war in March 2003 more than 500 troops have died from vehicle or aircraft crashes and other accidents such as falls, according to the data. Dozens more have drowned, while at least 26 troops were slain by fellow soldiers.

Another major cause of accidents are so-called negligent discharges - or accidental gunshots - which the Marine Corps report said increased every year between 2004 and 2008, including those involving "more senior, highly trained personnel." More than 180 troops have died from accidental gunshot wounds since the invasion, most recently two Marines in Anbar Province who died within the past two weeks, according to the Pentagon.

Miller said many of the accidental-discharge deaths involved units that had recently arrived in the combat zone, suggesting that lack of training played a role.

"Now you are armed to the teeth 24-7 and you are walking around essentially with a loaded weapon all the time," he said. "Even when you go to the shower you bring your personal weapon with you. There is a learning curve."

Other gunshot accidents have been traced to complacency or fatigue, he said. "If it's 3 o'clock in the morning and you've been on a combat patrol for the last eight hours you can sometimes miss some things," Miller said.

Now, the Marines are preparing an aggressive effort to get safety specialists into every major fighting unit overseas, recently approving plans to more than triple the number of so-called tactical safety specialists over the next 18 months from 78 to 245.

"Every infantry battalion, every combat logistics battalion, is going to have a full-time safety specialist to work with the commander to identify and abate the hazards and risks associated in theater," Miller said.

The Army is taking similar steps, according to retired Colonel James Yonts, a spokesman for the Army Safety Center at Fort Rucker.

"We are lacking in qualified safety officers who are out there with the commanders," he said.