More Than 600 Reported Chemical Exposure in Iraq, Pentagon Acknowledges More than 600 American service members since 2003 have reported to military medical staff members that they believe they were exposed to chemical warfare agents in Iraq, but the Pentagon failed to recognize the scope of the reported cases or offer adequate tracking and treatment to those who may have been injured, defense officials say. The Pentagon's disclosure abruptly changed the scale and potential costs of the United States" encounters with abandoned chemical weapons during the occupation of Iraq, episodes the military had for more than a decade kept from view. This previously untold chapter of the occupation became public after an investigation by The New York Times revealed last month that although troops did not find an active weapons of mass destruction program, they did encounter degraded chemical weapons from the 1980s that had been hidden in caches or used in makeshift bombs. The Times initially disclosed 17 cases of American service members who were injured by sarin or a sulfur mustard agent. And since the report was published last month, more service members have come forward, pushing the number who were exposed to chemical agents to more than 25. But an internal review of Pentagon records ordered by Defense Secretary Chuck Hagel has now uncovered that hundreds of troops told the military they believe they were exposed, officials said. The Secret Casualties of Iraq's Abandoned Chemical Weapons The Pentagon kept silent as munitions left over from Saddam Hussein's war with Iran found new targets from 2004 to 2011: American and Iraqi troops. The new and larger tally of potential cases suggests that there were more encounters with chemical weapons than the United States had acknowledged and that other people - including foreign soldiers, private contractors and Iraqi troops and civilians - may also have been at risk. Having not acted for years on that data, the Pentagon says it will now expand outreach to veterans. One first step, officials said, includes a toll-free national telephone hotline for service members and veterans to report potential exposures and seek medical evaluation or care. Phillip Carter, who leads veterans programs at the Center for a New American Security, called the Pentagon's failure to organize and follow up on the information "a stunning oversight." Paul Rieckhoff, founder and executive director of Iraq and Afghanistan Veterans of America, said the military must restore trust by sharing information. "We need total transparency and absolute candor," Mr. Rieckhoff said, and noted the military's poor record in releasing information about its use in Vietnam of Agent Orange, a chemical defoliant linked to an array of health problems, and in sharing data about troops" presumed chemical exposures and other medical and environmental risks during and soon after the 1991 Persian Gulf war. Military officers said the previously unacknowledged data was discovered when, at Mr. Hagel's prodding, the Army's Public Health Command examined its collection of standardized medical-history surveys, known as post-deployment health assessments, which troops filled out as they completed combat tours. Photo Some of the chemical projectiles discovered in December 2006 in Iraq, awaiting disposal. Credit The New York Times The assessments included the following question: "Do you think you were exposed to any chemical, biological and radiological warfare agents during this deployment?" For those who answered "yes," the forms provided a block for a brief narrative explanation. Col. Jerome Buller, a spokesman for the Army surgeon general, said Thursday that the review showed that 629 people answered "yes" to that question and also filled in the block with information indicating chemical agent exposure. Those who answered the questionnaire would have received medical consultations at the end of their combat tours, Colonel Buller said. Why the military did not take further steps - including compiling the data as it accumulated over more than a decade, tracking veterans with related medical complaints, or circulating warnings about risks to soldiers and to the Department of Veterans Affairs - remained unclear. Before post-deployment assessments were reviewed, Colonel Buller said, the Public Health Command had already expanded its search for potential victims and intended to examine the medical records of all troops assigned to units that the Army has belatedly acknowledged handled chemical weapons or were attacked with them. Chemical Secrets of the Iraq War The United States went to war in Iraq expecting to destroy an active weapons of mass destruction program. Instead, it found only remnants of chemical arms built in close collaboration with the West. Video by Mac William Bishop and C.J. Chivers on Publish Date October 14, 2014. Photo by Roberto Schmidt/Agence France-Presse - Getty Images. These include three Army explosive ordnance disposal companies and B Company, First Battalion, 14th Infantry, he said. Veterans said this unit list was incomplete and would inevitably grow as the military accounted for other high-risk troops, including those on route-clearance duties in areas where chemical roadside bombs were repeatedly found, or chemical warfare troops who served in so-called technical escort units, which were assigned to collect and analyze the old chemical weapons. Nonetheless, the new data has prompted the Public Health Command to take further steps, Colonel Buller said. These will include identifying all veterans who reported a possible chemical exposure, gathering their medical records, contacting them for a structured interview and perhaps inviting them for a medical exam. He said the Department of Defense had also revived a telephone line, 1-800-497-6261, for veterans to notify the Pentagon that they may have been exposed. The phone line, he said, had previously been used for veterans reporting Gulf War-related illnesses. OPEN Document Document: In Army Health Surveys, Troops Report Chemical Weapons Exposure in Iraq Immediate reactions among exposed service members and veterans" advocates mixed cautious appreciation with skepticism. "It's too little, too late," said Jordan Zoeller, a former Army sergeant who served in a platoon that was exposed to a sulfur mustard agent as soldiers destroyed buried chemical artillery shells near Taji in 2008. Mr. Zoeller was medically retired after developing a series of health problems, including asthma and psoriasis. He said his breathing trouble began within weeks of the chemical episode, though he is not sure its onset was related to a mustard agent because the Army denied that he had been exposed and did not examine his claims. "No one ever believed me," he said. "They were like, "Oh, that never happened." " He said at one point after he returned to the States and coughed up blood and lost consciousness, a regimental surgeon agreed to look into the episode. Nothing came of it, he said. Document: Exchange Between Hagel and Congress on Chemical Weapons Exposure in Iraq Another veteran, a Navy explosive-ordnance disposal technician who remains on active duty, said he was burned on the left forearm in December 2006 when handling 114 American-designed M110 mustard shells at a bomb makers" weapons cache near Samarra. He said that after the mustard agent splashed on his arm, he quickly rinsed it away by squirting it repeatedly with solution from IV bags. The mustard agent still caused a long patch of redness that took weeks to heal and left scarring, he said. The sailor, who asked that his name be withheld, said when he sought treatment at Forward Operating Base Brassfield-Mora, the Army doctor was not interested. An officer in the unit to which he was assigned - a battalion from the 505th Parachute Infantry Regiment, he said - issued what he called "a gag order" that forbade him to discuss that he had found chemical shells. The sailor's post-deployment health survey, which he provided to The Times, shows he reported the exposure again as he left Iraq in late 2007. Document: Medical Records of U.S. Casualties of Iraq's Chemical Weapons The attending caregiver did not recommend further care, but noted the previous order prohibiting mention of the episode. The patient, he wrote, "was instructed not to discuss due to mission classification." Cmdr. Ryan Perry, a Navy spokesman, said that the sailor had discussed the exposure with the Navy in recent days and that any previous order of silence was unacceptable. "We in no way condone the silencing of any of our service members," he said, "and are greatly encouraged that this sailor took the step of reaching out to the Navy so we can get him the medical attention he needs." While exposure to nerve or blister agents can carry long-term health risks, veterans, medical officers and exposure victims said that it was impossible to analyze the new data immediately and predict how many troops who reported exposure would have suffered medical problems. They said it could also be difficult to establish how closely medical complaints might be linked to exposure. They noted that many of the troops" encounters with chemical agents could have been brief and minimal, as that of a turret gunner in a vehicle passing briefly through an area where a chemical shell had been used in a makeshift bomb. Moreover, not all chemical agents were alike. The nerve agents found in Iraq after the United States invaded in 2003 were less potent than when manufactured decades ago, according to people involved in many of the chemical arms recoveries in Iraq. Iraqi mustard agents tended to be of higher quality and more stable, they said. Nonetheless, Mr. Carter and Mr. Rieckhoff said that the latest number was probably understated, and that the military should not rely on people who reported chemical weapons exposures to determine the scope of the problem. It should look deeper, Mr. Carter said, at symptoms, such as troops who reported rashes, breathing difficulties or tremors.