Under this system, some service members finally received recognition and treatment for their injuries that for years they had been denied. As of April of this year, medical records for more than 7,900 service members had been reviewed and 324 of them had undergone screening at Walter Reed National Military Medical Center. Of these 324 people, the Army has identified 153 with “confirmed or likely symptomatic exposure,” according to John Resta, director of the Army Public Health Center. Some have been awarded Purple Hearts from their respective services. But after submitting medical records, offering written statements about the incident and undergoing medical exams, Nellis and her three colleagues have yet to receive an acknowledgment of their exposure from the Air Force. The veterans have become victims two times over: once as a result of exposure that left them with chronic injuries and again as casualties of a bureaucratic system that seems to have unraveled as quickly as it was built.

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After returning to the operating base, Nellis saw pinhead-size blisters forming on her face and chest. Within six hours, those blisters had each grown to half the size of a dime. But she and another airman, Brian Ornstein, did not seek medical care immediately, despite their symptoms. According to both of them, they were told not to discuss what happened, although neither remember by whom. Ronnie Walker, the machine-gunner who called in the Code Four, was evaluated and treated by an Air Force doctor for minor eye, nose and throat irritation. Steven May, the pararescueman who collapsed, was briefly hospitalized for observation and decontamination; he said that he remembers almost nothing from the incident or the three days afterward.

For the rest of that deployment, Nellis had trouble breathing and felt that her lungs and nasal passages were obstructed. Her blisters turned into scars. By 2008, more than two years after the incident, she had developed chronic insomnia; she continues to wake up in the middle of the night unable to breathe, despite having surgery to repair her deviated septum. Memory problems soon followed. Today Nellis also experiences constant pain from unhealed sores in her left nasal passage, which leads her to clench her jaw involuntarily. Her jaw is misaligned as a result. She has spent thousands of dollars to hide the scars she now has on her face and chest, and minimal exposure to sunlight causes any exposed skin to burn easily.

Nellis isn’t the only one suffering from chronic health issues. Walker has problems with his central nervous system, which at one point left him bedridden for close to a year. Less than a year after the mission, Brian Ornstein, who was healthy and athletic before Taji, started to experience muscle weakness in his feet. Then doctors found an unexplained blind spot in his left eye. By October 2010, he says, he was suffering from headaches that lasted almost all day, every day, many of them migraines. Doctors warned him that his body was shutting down, but then they also accused him of being a malingerer. At one point he was bedridden for two years. It was only when the four airmen reconnected in 2015 that they came across The Times’s report that documented multiple incidents of chemical-weapons exposure in Iraq. They realized that they, too, may have been affected. “We put two and two together and realized we were all on the same mission where we got exposed,” Walker said.