In the late morning of March 16, 1988, an Iraqi Air Force helicopter appeared over the city of Halabja, which is about fifteen miles from the border with Iran. The Iran-Iraq War was then in its eighth year, and Halabja was near the front lines. At the time, the city was home to roughly eighty thousand Kurds, who were well accustomed to the proximity of violence to ordinary life. Like most of Iraqi Kurdistan, Halabja was in perpetual revolt against the regime of Saddam Hussein, and its inhabitants were supporters of the peshmerga, the Kurdish fighters whose name means “those who face death.”

A young woman named Nasreen Abdel Qadir Muhammad was outside her family’s house, preparing food, when she saw the helicopter. The Iranians and the peshmerga had just attacked Iraqi military outposts around Halabja, forcing Saddam’s soldiers to retreat. Iranian Revolutionary Guards then infiltrated the city, and the residents assumed that an Iraqi counterattack was imminent. Nasreen and her family expected to spend yet another day in their cellar, which was crude and dark but solid enough to withstand artillery shelling, and even napalm.

”At about ten o’clock, maybe closer to ten-thirty, I saw the helicopter,” Nasreen told me. “It was not attacking, though. There were men inside it, taking pictures. One had a regular camera, and the other held what looked like a video camera. They were coming very close. Then they went away.”

Nasreen thought that the sight was strange, but she was preoccupied with lunch; she and her sister Rangeen were preparing rice, bread, and beans for the thirty or forty relatives who were taking shelter in the cellar. Rangeen was fifteen at the time. Nasreen was just sixteen, but her father had married her off several months earlier, to a cousin, a thirty-year-old physician’s assistant named Bakhtiar Abdul Aziz. Halabja is a conservative place, and many more women wear the veil than in the more cosmopolitan Kurdish cities to the northwest and the Arab cities to the south.

The bombardment began shortly before eleven. The Iraqi Army, positioned on the main road from the nearby town of Sayid Sadiq, fired artillery shells into Halabja, and the Air Force began dropping what is thought to have been napalm on the town, especially the northern area. Nasreen and Rangeen rushed to the cellar. Nasreen prayed that Bakhtiar, who was then outside the city, would find shelter.

The attack had ebbed by about two o’clock, and Nasreen made her way carefully upstairs to the kitchen, to get the food for the family. “At the end of the bombing, the sound changed,” she said. “It wasn’t so loud. It was like pieces of metal just dropping without exploding. We didn’t know why it was so quiet.”

A short distance away, in a neighborhood still called the Julakan, or Jewish quarter, even though Halabja’s Jews left for Israel in the nineteen-fifties, a middle-aged man named Muhammad came up from his own cellar and saw an unusual sight: “A helicopter had come back to the town, and the soldiers were throwing white pieces of paper out the side.” In retrospect, he understood that they were measuring wind speed and direction. Nearby, a man named Awat Omer, who was twenty at the time, was overwhelmed by a smell of garlic and apples.

Nasreen gathered the food quickly, but she, too, noticed a series of odd smells carried into the house by the wind. “At first, it smelled bad, like garbage,” she said. “And then it was a good smell, like sweet apples. Then like eggs.” Before she went downstairs, she happened to check on a caged partridge that her father kept in the house. “The bird was dying,” she said. “It was on its side.” She looked out the window. “It was very quiet, but the animals were dying. The sheep and goats were dying.” Nasreen ran to the cellar. “I told everybody there was something wrong. There was something wrong with the air.”

The people in the cellar were panicked. They had fled downstairs to escape the bombardment, and it was difficult to abandon their shelter. Only splinters of light penetrated the basement, but the dark provided a strange comfort. “We wanted to stay in hiding, even though we were getting sick,” Nasreen said. She felt a sharp pain in her eyes, like stabbing needles. “My sister came close to my face and said, ‘Your eyes are very red.’ Then the children started throwing up. They kept throwing up. They were in so much pain, and crying so much. They were crying all the time. My mother was crying. Then the old people started throwing up.”

Chemical weapons had been dropped on Halabja by the Iraqi Air Force, which understood that any underground shelter would become a gas chamber. “My uncle said we should go outside,” Nasreen said. “We knew there were chemicals in the air. We were getting red eyes, and some of us had liquid coming out of them. We decided to run.” Nasreen and her relatives stepped outside gingerly. “Our cow was lying on its side,” she recalled. “It was breathing very fast, as if it had been running. The leaves were falling off the trees, even though it was spring. The partridge was dead. There were smoke clouds around, clinging to the ground. The gas was heavier than the air, and it was finding the wells and going down the wells.”

The family judged the direction of the wind, and decided to run the opposite way. Running proved difficult. “The children couldn’t walk, they were so sick,” Nasreen said. “They were exhausted from throwing up. We carried them in our arms.”

Across the city, other families were making similar decisions. Nouri Hama Ali, who lived in the northern part of town, decided to lead his family in the direction of Anab, a collective settlement on the outskirts of Halabja that housed Kurds displaced when the Iraqi Army destroyed their villages. “On the road to Anab, many of the women and children began to die,” Nouri told me. “The chemical clouds were on the ground. They were heavy. We could see them.” People were dying all around, he said. When a child could not go on, the parents, becoming hysterical with fear, abandoned him. “Many children were left on the ground, by the side of the road. Old people as well. They were running, then they would stop breathing and die.”

Nasreen’s family did not move quickly. “We wanted to wash ourselves off and find water to drink,” she said. “We wanted to wash the faces of the children who were vomiting. The children were crying for water. There was powder on the ground, white. We couldn’t decide whether to drink the water or not, but some people drank the water from the well they were so thirsty.”

They ran in a panic through the city, Nasreen recalled, in the direction of Anab. The bombardment continued intermittently, Air Force planes circling overhead. “People were showing different symptoms. One person touched some of the powder, and her skin started bubbling.”

A truck came by, driven by a neighbor. People threw themselves aboard. “We saw people lying frozen on the ground,” Nasreen told me. “There was a small baby on the ground, away from her mother. I thought they were both sleeping. But she had dropped the baby and then died. And I think the baby tried to crawl away, but it died, too. It looked like everyone was sleeping.”