Shigeko Sasamori, who was severely burned at age 13 when a nuclear bomb exploded over Japan and later, in the United States, championed peace and found comfort in helping others as a nurse’s aide, died Dec. 15 at her home in Marina del Rey.

She was 92.

Her son, Norman Cousins Sasamori, confirmed her death.

Sasamori spoke gently, but resolutely, against nuclear war to audiences who included students, United Nations interns and guides, and members of the U.S. Senate. Her message carried no rancor toward the United States.

“I have a mission to tell people that this should not happen again,” she told a Senate subcommittee investigating the effects of nuclear war on human health in 1980. “I tell people how horrible it was and how horribly we suffered even though we were children. The next generation of children has come into the world, and I fear for them.”

Her death came two months after the Nobel Peace Prize was awarded to Nihon Hidankyo, a grassroots Japanese organization of atomic bomb survivors, for its efforts to rid the world of nuclear weapons.

On the morning of Aug. 6, 1945, Sasamori was one of the students assigned to clear the streets of Hiroshima of debris to make the city easier to evacuate if necessary. She heard a buzzing sound from the sky and told a classmate, “Look at the white thing falling from that airplane.”

Then, she recalled, she heard a “boom,” and she was knocked out by the bomb’s blast wave.

She had no idea how long she remained unconscious. But when she opened her eyes, darkness from the dust and smoke enveloped her.

Desperate and fearful, Sasamori followed other bloodied survivors — some naked, some with their skin peeled away — to a makeshift shelter at an elementary school.

Once there, she cried for water and called out her name and address, hoping someone would locate her parents. One-third of her body — her face, back, neck, chest, shoulders, arms and hands — was burned.

“I didn’t feel any pain — numb, just numb,” she said.

Her parents found her after several days and brought her home.

Her head was badly swollen and disfigured. Her fingers were stuck together. Her mother treated her by soaking pieces of cloth in cooking oil and wiping pus from her body.

“Eyebrows, lashes and hair were gone,” Time magazine reported in 1955. “Worst of all, her chin had all but disappeared, and the lower half of her face looked as though it had been melted into her throat.”

Some 200,000 people in Hiroshima are believed to have died within five years as a result of the blast and its long-term effects, according to the U.S. Department of Energy.

Sasamori recovered slowly, but she needed more treatment than reconstructive surgery in Japan could offer. In 1955, she was one of 25 young women disfigured by the bomb who were chosen to receive surgery at Mount Sinai Hospital in New York City as part of a mission arranged by Norman Cousins, editor of Saturday Review magazine. His visit two years earlier to Japan, where he met Sasamori, had prompted him to help the bomb’s victims.

Most of the Hiroshima Maidens, as the women were called, stayed with Quaker families during their postsurgical recoveries. But Sasamori lived mostly with Cousins’ family in Connecticut, said Candis Cousins, one of Cousins’ four daughters.

“She established a special relationship with my father,” Cousins said. “I’m grateful that he brought Shigeko into our lives; part of my education was living with someone who had been through nuclear war and had her face severely burned.”

Sasamori’s multiple surgeries, which took place over more than a year, restored her face and chin and improved the use of her fingers, although her scars were still visible.

In November 1956, while in San Francisco on her way home to Japan, she told The Times-Gazette of San Mateo that she was eager to return home but that she would miss the United States.

“The people have been so kind,” she said. “I am so happy about what has happened to me. I can use my hands now.”

She paused and then added, “Oh, but there mustn’t be any more war.”

Shigeko Niimoto was born June 16, 1932, in Hiroshima, not far from the epicenter of the nuclear bomb.

The blast delivered her into a hell on Earth, where “everything is not human,” she once told Meyer Berger, a columnist for The New York Times.

“No faces, no eyes, and red and burned all things, like woman hair awful looking, dusty and smoking with burning.”

Soon after her reconstructive surgeries, she returned to the United States.

In 1958, on the 13th anniversary of the Hiroshima bombing, hundreds of people marched from Bryant Park in midtown Manhattan to United Nations Plaza, where they presented her with flowers.

Wearing white gloves to cover her misshapen hands, she told the marchers that she wanted to become a “citizen of the world.”